The short answer is yes, the medium sized answer is yes in all cases and the long answer well, it’s given below.

Let us take the Nexon EV for reference, it has an ARAI certified range of 312km and a 30.2kWh battery. Let us take the worst-case scenario which is the most polluting scenario and assume all of the electrical power needed to charge the EV comes from thermal power, the amount of fuel that would be burnt to fully charge the battery would be as follows [3,4],

· 3.75kg of bituminous coal i.e., 8.45kg of total CO2 emissions or 0.027kg/km.

· 1.85 litres of petrol i.e., 7.85kg of total CO2 emissions or 0.0025kg/km

Now these values of emissions are in addition to the 1842.2kg to 3020kg of CO2 emissions which are a result of the manufacturing of the battery pack which is only a one-time emission.

Now, let us take the Nexon petrol for reference, this car has an ARAI certified mileage of 17km/l, this results in a carbon footprint of 4.25kg of CO2 per km driven. (For the purpose of consistency, I have taken ARAI certified figures for both vehicles, real life values may differ.)

From the above figures, it is clear that as an EV is driven, its carbon footprint keeps shrinking and the more the EV is driven, the more its carbon footprint shrinks to the point where the carbon footprint of the EV falls below that of an ICE vehicle within the first 2–4 years of driving (even when it is powered by thermal power!), switching over to zero-emissions sources of power such as hydroelectric, nuclear and solar power, the carbon footprint of an EV would shrink faster.

Now, how about the cost of owning an EV? Aren’t EVs more expensive to begin with? Yes, they are because, they’re a relatively new technology and aren’t being produced in large volumes plus, everything that’s new comes with an “early adopter” tax. But still, let us do a little but of mathematics here as well,

The on-road price in Delhi for the base variant of the petrol-driven Nexon is ₹8.19 lakhs, assuming that you’re an average Indian driver like me, you might be driving around 1000km per month which leads to a monthly petrol cost of ₹5800 per month at a minimum. Further, a petrol driven car requires more frequent maintenance than an EV. Services such as oil-changes, brake pads and regular wear and tear of the engine, the costs of this also add up significantly. On the other hand, in the Nexon EV which has an on-road price of ₹14.69 lakhs, costs ₹241.6 to fully charge leading to a minimum monthly bill of ₹724.8. The only maintenance that would be needed in an EV is for consumables like brake pads and tyres, thanks to technologies such as regenerative braking in the Nexon EV, its brake-pads will wear out slower than the ones on its petrol counterpart. The aspect of battery degradation comes after driving the EV for at least 1 lakh kilometres or around 8 years after which you’ll be needing a new battery. But what happens to the old one? Won’t dumping it harm the environment? Maybe this is why EVs should be avoided at all costs! Wrong again! Old EV batteries are perfectly usable for non-automotive applications, you can use these batteries for backup power yourself or your EV manufacturer, would sell the battery pack to those who need batteries for energy storage. These batteries are rated to function for 10 years after they’ve been discarded by an EV driver. Several start-ups such as Nunam are actually working on giving these batteries a second life in smartphones, laptops or even in medium to large scale applications such as power inverters [5]. Further, there’s ongoing research on extracting several useful metals such as Cobalt, Nickel, Magnesium etc. from Lithium-ion batteries.

Now that you know that an EV will save your wallet in addition to saving the environment, why not consider buying an EV especially when petrol prices have skyrocketed?

References

[1] https://powermin.gov.in/en/content/power-sector-glance-all-india

[2] https://www.carbonbrief.org/factcheck-how-electric-vehicles-help-to-tackle-climate-change

[3] https://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html

[4] https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085.html

[5] https://auto.economictimes.indiatimes.com/news/auto-components/evs-battery-waste-and-million-dollar-opportunity/77215015#:~:text=The%20two%20most%20rational%20solutions,of%20less%20than%20ten%20years.

Are EVs Really That Bad? was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

In a recent survey carried out in the American state of California, nearly a fifth of EV owners reported that they regretted purchasing an EV and cited range anxiety and charging infrastructure as the key reasons. I somewhat disagree with this conclusion and feel that it is slightly skewed and biased as it does not take into account the kind of EV that the owner owns, the different types of charging connectors used by EV manufacturers (CCS 2, Chad EMO, Tesla to name a few) and technically, even Hydrogen fuel-cell driven vehicles are EVs!

The concerns expressed by the EV owners are genuine and legitimate and the fact that our country is a developing country with a per capita GDP of US$2190 (exchange rates) or US$7333(PPP adjusted, I’ll go with the PPP figure as it shows the actual purchasing power of the average Indian),[1] the problem of EV infrastructure seems to be even worse in our context because to most of us, if a “first world country” couldn’t solve its problem of EV infrastructure, then how can a “developing country” do so? As counterintuitive my claim might seem, most countries don’t need to solve their problem of EV charging infrastructure, because they already have it! Let me explain,

Most countries, India and the US included have the capacity to supply electricity to more than 95% of their population for an average duration of over 20 hours a day. (97.8%, 20.6 hours in case of India and 100%, 21.33 hours in case of the US) [2]. Yes, the US has a higher installed capacity of 1117GW whereas we have an installed capacity of 383GW [3] but this difference won’t affect my claim that we have most of the infrastructure necessary for EVs. The basic fuel that propels an EV forward is electricity and electricity is everywhere, wherever you are, you’re quite likely to find a wall socket that would be capable of charging your EV to a reasonable level. Most homes/commercial establishments have 15A sockets available that will be capable of topping up a Nexon EV at a steady pace of around 10.3% per hour so, if you were to plan your road trip in 100km sections with a 20–30-minute break in between, you would be able to charge your EV by around 5% if you were to halt at a local dhaba. Plus, if you were to halt at a Tata, Mahindra or MG dealership, you might get access to a DC fast charger as most of their dealerships have them installed. However, the number of DC fast chargers on highways is still too few and they are too far apart. These can fully charge your EV in about an hour.

So, for ultra-long road trips (more than 500km), you’ll have to plan your stopovers in such a way that you get access to a slow charging point (any 15A socket with proper earthing will do) where you may have to spend a couple of hours before continuing on your journey, in case there are no or very few fast chargers en-route to your destination . But still, Murphy’s law dictates that anything that can go wrong will go wrong. So, in case you’re stranded with little to no charge to spare, what do you do? Your best option is to call up road side assistance who will reach you wherever you are and give you a top up of 5kWh which will be good enough for you to travel around 30km. In the rarer case that help doesn’t arrive, there is still something that you can do. Understand that all EVs equipped with regenerative braking can be tow-charged, i.e., if you were to tow your EV, then the battery would get charged via the regenerative braking system and you might gain around 1% charge per km of towing. So, by the time you reach the nearest dhaba, you might gain around 20km of range just by having your EV towed. Do this only in an emergency as a regen system is not designed to supply power continuously for a long period of time and this should be your last option only. Note that your EV must be in D or S mode for the regen system to work and keep a strong tow-cable handy.

But this is all fine, what to do when my landlord/housing society isn’t allowing me to install a charger for my EV at home? This is slightly difficult, in case you live in a rented house or an apartment, there are a few things that you’ll have to do,

· Assure the owner/housing society that the cost of charging your EV will be on your electricity bill and will be borne by you and not the housing society.

· Convince them that petrol is too expensive and this is why you’re planning to purchase an EV (this might convince them also to buy an EV)

· Find out if your neighbours are also interested in purchasing an EV, go together with them and raise this issue during the society meeting(s)

· A radical solution, take one of your neighbours to an EV test drive, they’ll enjoy an EV like the Nexon and might be willing to support you in getting you permission to install a charging station.

· If they still don’t permit, you can request them to allow you to install a 15A outlet in your parking spot and that will be enough for your Nexon EV (both the dedicated wall-box charger and the 15A outlet charge at the same speed)

· In case you live in an apartment where parking spots are not assigned, request your society to allow to pick a particular spot to charge your EV and ensure that no one else uses your spot.

· If you park outside on the road, it is not safe for you to draw a wire from your meter as the charger may get vandalised and it might also be illegal, instead, you can request people at your workplace to allow you to have a charger/outlet installed and your EV would get charged while it is sitting idle in the office parking lot.

But then what should institutions/departments do to improve EV charging infrastructure and increase EV adoption? Our country would be able to save several billions of rupees lost in oil imports if we all were to switch to EVs. Here is a list of a few things that can be done,

· If you hold a position of authority in a housing society, allow your fellow members to have EV charging units installed, the cost will be borne by the EV owner and not the society, so it won’t be a financial burden on the housing society.

· Ministries of Power, Road Transport and Highways and Urban Development must come together and formulate policies and protocols for individuals to setup charging stations at home. Policies such as reduced property tax, reduced cost of electricity etc., for homes/establishments with EV charging stations might help accelerate the EV adoption.

· The government can also make it mandatory for all home owners, housing societies etc. to allow their tenants to have an EV charging station and make it illegal for them to deny permission.

· If you’re an entrepreneur, you can install either fast or slow charging stations in the city or between cities (more on this in my next article), initial revenues might not be much and this must be treated as a long-term investment.

· EV manufacturers must standardise their chargers, this will give the user a greater deal of flexibility and peace of mind knowing that they can use any charger that is available. This will also create economies of scale and reduce the per unit cost of manufacturing and installing EV chargers.

References

[1] https://www.downtoearth.org.in/blog/energy/access-to-electricity-improves-across-states-urban-rural-divide-remains-nfhs-5-74890

[2] https://tradingeconomics.com/united-states/access-to-electricity-percent-of-population-wb-data.html#:~:text=Access%20to%20electricity%20(%25%20of%20population)%20in%20United%20States%20was,compiled%20from%20officially%20recognized%20sources.

[3] https://tradingeconomics.com/india/access-to-electricity-percent-of-population-wb-data.html

ALL IMAGES HAVE BEEN SOURCED FROM GOOGLE.

Bibliography

1. https://www.ceew.in/publications/state-electricity-access-india

2. https://www.eia.gov/energyexplained/electricity/electricity-in-the-us-generation-capacity-and-sales.php#:~:text=At%20the%20end%20of%202020,solar%20photovoltaic%20electricity%20generating%20capacity.

3. https://powermin.gov.in/en/content/power-sector-glance-all-india

4. https://www.youtube.com/watch?v=QhWBqlCTjlM&t=342s

5. https://www.youtube.com/watch?v=vFfba6Y2DzE

6. https://www.youtube.com/watch?v=Hblri2FGKS0

Range Anxiety and Charging Infrastructure was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

Let us first discuss on the kinds of chargers that are generally used for charging up EVs,

· Level-1 or AC slow charging (1.25kW to 3kW)

· Level-2 or AC fast charging (7kW to 22kW)

· Level-3 or DC fast charging (25kW and above)

Level-1 Charging;

In case of Level-1 charging very little work needs to be put in for setting up a charging station as it can be done from any 15A wall socket like the one shown in the figure. Though not mandatory, always prefer installing a socket that comes with an MCB as it provides protection against various electrical faults such as short-circuits, over-voltage, over-current etc.

A Nexon EV would take around 8–10 hours to get fully charged, so setup isn’t viable for people who might be using your charging station for a short period of time. Such a setup would be quite viable if you own any of the following businesses,

· A restaurant where people generally spend about an hour, their EVs could gain around 10% charge, you could charge EV owners lower parking fees and make money by charging them extra for using your charging station, you could either charge on the basis of the overall duration your station was used or on the basis of the number of units consumed by your customer’s EV.

· A movie theatre where customers generally spend upwards of 2 hours, you can follow the same business model given above, you might also offer EV owners discounted tickets or complimentary popcorn as you’ll be covering up the cost from your charging station. This will not only bring you profits but also encourage your customers to buy EVs thereby increasing their adoption, reducing pollution, making the environment cleaner. In a nutshell, a multi-win situation.

· A hotel where your customers generally stay for upwards of 5 hours. Here, you’ll have to make a few adjustments to the above models. Here, there is a probability of you customer’s EV reaching 100% state of charge and under these circumstances, you’ll have to setup a system that immediately disconnects the EV once it is fully charged, else you’ll end up in a situation where your charging station is being used but isn’t making much money. And other customers who might be needing a charge might not be able to get it as an available charging station is connected to a vehicle.

In case your business has space for 2-wheeler parking, you could install 5A sockets, a typical Ather 450X would take around 2.5 hours to get fully charged from such an outlet.

None of the above models require you to do unnecessary steps such as speaking to officials in the electricity department, getting additional power connections etc. as this process simply involves purchasing a few 15A outlets and installing them. Your overall investment in installing such as charging setup should not exceed ₹20,000 even when you’re planning to install dozens of outlets. (Including cost of wiring, installation, materials etc.)

Level-2 Charging;

Most commercial establishments come with a 3-phase power connection, so you’re good to go connection wise. Installation of 3-phase outlets is slightly more complicated than installing an ordinary outlet, speak to a qualified professional before proceeding with such a step. You could use a 3-phase outlet in the above situations, but remember, you’ll have to charge more from your customers as 3-phase charging stations are more expensive and the fixed cost component in your electricity bill may go up in case you decide to install one.

You can offer this as an “express charging” service and have a limited number of charging stations. Remember, a mere 3-phase outlet may not be sufficient as most portable chargers that EVs are equipped with don’t support 3-phase power. Instead, you’ll have to speak to automobile manufacturers who have the skill and technology to install such charging stations at your place.

You’ll have to go through the hassle of producing and reviewing several documents before you can get these installed. Alternatively, you could purchase an EV like the MG ZS EV and have them install a charging station at your business establishment. This will smooth out the process, but obviously, do this only if you’re planning to buy an EV. Since only a limited number of EVs support Level-2 charging, install only a limited number of outlets and consider this only if your business is in or close to an area where people own such EVs.

The cost of such charging stations is upwards of ₹37,500 each, so choose wisely before installing such a charging station in your business.

Level-3 Charging

DC fast charging stations require you to have an industrial 3 phase connection that is capable of delivering more than 25kW of power. Go through your state electricity department’s website before obtaining approval for such a connection.

Such a charging setup is suitable mostly in cases where the customer won’t be parking their EV at your business for more than an hour or so. In case you own a fueling station, you could setup one to ensure that you don’t go out of business once EVs become mainstream. Since you’ll be going for an industrial connection, you’ll be charged more by your electricity company both in terms of fixed cost and per unit cost. So be sure to charge your customers accordingly.

In addition to state government regulations, there are some set by the central government as well, several online portals such as ecogears have most of the necessary information regarding these in a well curated manner.

A DC fast charger (under 50kW) will set you back by at least ₹1.5 lakhs, this does not include the cost of getting an industrial connection, wiring etc.

How about setting up a dedicated EV charging station business?

Installing Level-1 chargers as a dedicated business might not be a very good idea as the revenue flow would be too slim for you to justify any investment. Level-2 and Level-3 chargers cost more but there are a few ways you could make money off of them if you were to think innovatively.

One of the ways that I think can ensure a steady stream of revenue irrespective of whether EVs come up for a charge or not is using grid-connected solar systems. Such a solar system supplies power to the grid during the day and draws power from the grid at night.

You could install a 6kW solar system for your charging station and equip it with a 3-phase inverter, this would supply power to the grid while not in use during the day and when an EV does come up for a charge, it could either use Level-2 charging or Level-3 charging depending upon the equipment that is installed in the charging station

Opting for Level-3 charging would be a better option in the Indian context as the most popular EVs in India such as the Nexon and the Mahindra E2O aren’t equipped with 3-phase chargers but are compatible with DC-fast charging, this will allow you to reach a greater customer base and you’ll continue making money even if the chargers aren’t in use. Additionally, you could use the available space at the station for advertising or you could partner with companies such as Coca-Cola and have them set up vending machines at your station, this will keep a steady flow of revenue into your pocket. Note that a solar system would cost you around ₹3 lakhs for a 6kW unit, so plan your investment and calculate your RoI accordingly.

Note that you could setup charging stations using solar power at parking lots within the city as well.

All in all, it would suffice to say that EV charging stations are a viable business if planned the right way. Do go through the following sources that I had consulted for the purpose of this article as they will help you make a more informed decision in this field.

Bibliography

1. https://sinovoltaics.com/learning-center/electric-vehicles/solar-charging-stations-electric-vehicles-evs/

2. https://tsredco.telangana.gov.in/PDFs/Solar_Energy/Solar_Rooftop_Net_metering_Guidelines.pdf

3. https://www.indiamart.com/proddetail/dc-fast-chargers-for-ev-20695981388.html

4. https://ecogears.in/electric-car-charging-station-installation-cost-in-india/

5. https://www.indiamart.com/proddetail/ac-7-kw-home-charger-22398670462.html

6. https://www.solarexpertsindia.com/systems/6kw-solar-panel-inverter-battery-plant-price/

7. https://www.loomsolar.com/blogs/collections/how-to-apply-for-net-metering-state-wise-procedures

8. http://mohua.gov.in/upload/whatsnew/5c6e472b20d0aGuidelines%20(EVCI).pdf

9. https://www.moneycontrol.com/news/business/want-to-instal-a-public-charging-station-for-evs-heres-what-you-need-to-know-7119051.html

10. https://powermin.gov.in/sites/default/files/uploads/Revised_MoP_Guidelines_01_10_2019.pdf

Public Charging Stations: A few business ideas. was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

Your automobile is the second most expensive asset that you own after your home and most of us view more than just a mere mobility solution. Owning an electric automobile comes with its bells and whistles, it has its share of issues and a vehicle isn’t a pair of jeans that you can return to the seller if you don’t like it and getting rid of a car that you might not like is a real pain in the back end. Transferring registration and ownership documents, insurance and to add insult to injury, all vehicles without exception are depreciating assets, according to the omnicar car depreciation calculator, a vehicle loses about 9% of its original value within the first 1 minute of its purchase [1].

Now with such a rapid drop in value, it’s almost impossible to recover all of the hard-earned money that you have spent on your car. This is exactly why people are advised to be extremely careful and make informed decisions before making their car purchases. EVs actually depreciate much faster than conventional ICE cars because of the rapid advancements in battery, motor and electric drivetrain technologies. A used 2016 Tesla Model S costs around US$39,998 less than 50% of its original price of over US$80,000.[2]

Having said that, we must acknowledge that EVs are the future of both personal and mass transport and to make a wise investment, one must fully understand the positives and the negatives of owning, running and maintaining an EV.

The Good:

In addition to being great for the environment, EVs have the following advantages.

EVs last longer

Most ICE cars are rated to last around 300,000km before the cost of maintenance becomes too high to be justified and unless you own a Toyota or a Honda it’s not very likely that your car will last any longer. According to Tesla, an EV battery would last around 10 years or between 200,000km to 320,000km before the battery pack becomes unusable by then the cost of batteries would be so low that it would be better for you to replace just the battery than to go ahead and purchase a whole new car and once the battery pack is replaced, it will last for an additional decade. [3] Other components such as the power electronic components, the motor etc. won’t degrade by a significant margin even after using them for a decade and typically are guaranteed to last 15 to 20 years. [4]

EVs are low maintenance

Extremely low maintenance. An ICE car has around 4000 components that work independently and any of them can go wrong. A typical EV even when it is fitted with the latest tech has less than 1000 and except for the motor, the tyres and the brakes, there are virtually no moving parts which means very little wear and tear. Thanks to technologies like regenerative braking, the brake pads will last longer and run cooler than those on a typical ICE vehicle. And there are no complicated oil changes, oil filter changes etc. that you’d typically need to do in your ICE car every few thousand kilometres and this results in significantly lower costs associated with the maintenance of your vehicle. Additionally, the lower number of moving parts also reduces the chances of mechanical failure, resulting in a safer driving experience.

Electricity was, is and always will be cheaper

Electricity in India is dirt cheap, costs less than ₹8 per unit in most cities. A typical Nexon EV costs less than ₹1 per km to run and an e-scooter like the Pure EV E-Pluto 7g costs only ₹0.1 per km to run. A conventional ICE car running on petrol would easily set you back by ₹10 per km and an ICE scooter would set you back by at least ₹1.5 per km. Plus, electricity prices have been stable for over a decade in India [5]

At first glance, it might seem from the graph that electricity prices have doubled in over a decade, but once inflation is taken into account, the cost of electricity doesn’t seem to have changed by much. On the other hand, petrol prices have shown themselves to be as volatile as petrol itself and its quite possible that over the next few years, petrol will continue getting more and more expensive and electricity will become more and more accessible and affordable.

EVs are like wine, they get better with age

An EV is primarily software-driven, the overall experience can be improved throughout an EV’s life through software updates. With just a few tweaks in the software, an EV can be made to go faster or be more efficient. Additionally, all components of an EV are electronically controlled, they are much easier to automate.

The bad

Not a lot of things are bad about EVs per se, but still, they do come with their fair share of flaws.

EVs are harder to fix

A typical EV has fewer parts to fix, to begin with, but these parts are quite sophisticated and a higher level of technical skill and knowledge is required to repair them in case something breaks under the hood. Components such as motor diver circuits, battery management systems, DC-DC converters have extremely complex components integrated into them and in several cases, it is cheaper to replace a failed component than to attempt any repairs due to the sheer complexity of electronic modules.

Software and hardware locks

Since an EV is primarily software-driven, it’s much easier for automakers to implement locks on the overall EV thereby blocking an owner from attempting any repairs on their own or depending upon third-party service stations which might be cheaper or better than the ones at the dealership. This might also block the user from making modifications to their vehicles. Additionally, automakers can deliberately disable certain features of an EV and force users to enter into subscription-based services. The legislature and the executive need to take cognizance of such a future in the automotive sector and act accordingly with proper regulatory frameworks that are in the best interests of consumers.

The ugly

There’s one and only one aspect about EVs that can be considered ugly and that is,

Poor resale value

EV technology is growing by leaps and bounds. Every year there is a new algorithm for BMS, an improvement in battery technology and an improvement in charging hardware onboard the vehicle. Plus there’s the aspect of battery degradation. All of this offsets any benefits that are associated with the lower wear and tear of the car’s components and its longer rated life and because of this, you might not be able to recoup a significant proportion of the money that you invest in an EV. But the amount of money that you end up saving in total running costs and maintenance might help you offset the losses associated with depreciation.

All in all EVs sound like a decent deal and by the end of this year, more EVs are expected to it the Indian market from the likes of Tata, Mahindra and Hyundai. Models such as the Altroz EV, the eXUV300, the eKUV100 are worth waiting for.

References

[1] https://www.omnicalculator.com/finance/car-depreciation

[2] https://www.edmunds.com/used-tesla-model-s/

[3] https://www.primecom.tech/blogs/news/electrical-vehicle-motor

[4] https://www.edfenergy.com/electric-cars/batteries#:~:text=Most%20manufacturers%20have%20a%20five,they%20need%20to%20be%20replaced.

[5] https://scripbox.com/plan/inflation-calculator

Bibliography

1. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.carwale.com%2Ftata-cars%2Faltroz-ev%2F&psig=AOvVaw1nB6CUzZIM87rgt5XhMmwR&ust=1625913817465000&source=images&cd=vfe&ved=0CAsQjhxqFwoTCODvtJvn1fECFQAAAAAdAAAAABAD

2. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.autocarindia.com%2Fcars%2Fmahindra%2Fexuv300&psig=AOvVaw0_VB2CT2SiRCrwNkKp_7a4&ust=1625914113506000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCOiQk6To1fECFQAAAAAdAAAAABAD

3. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.carwale.com%2Fmahindra-cars%2Fekuv100%2F&psig=AOvVaw2T1FVOL7T96EGV__zSeQhD&ust=1625914160586000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCMihtb3o1fECFQAAAAAdAAAAABAD

4. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwj13Yby59XxAhUt7HMBHet7CIMQFjAPegQIMBAD&url=https%3A%2F%2Fwww.myev.com%2Fresearch%2Fev-101%2Fhow-long-should-an-electric-cars-battery-last&usg=AOvVaw3ohMl3-59cjjckkwGoXyc5

5. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwj13Yby59XxAhUt7HMBHet7CIMQFjASegQIFRAD&url=https%3A%2F%2Fwww.geotab.com%2Fblog%2Fev-battery-health%2F&usg=AOvVaw0_xlmnwBLVrnSQA96VA0zf

Owning an EV: The good, the bad and the ugly was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

A typical Lithium-Ion battery pack consists of several tiny little batteries also commonly called as cells and they are connected together in series and parallel.

Connecting multiple cells in series increases the overall voltage of the battery pack and connecting them in parallel increases their capacity. To know the number of cells in series and in parallel for a given battery pack look for the “S-P” number for example a “2S-3P” connection means 2 cells in series and 3 cells in parallel. In case either of the alphabets is missing say only “2S” or “2P” is written on the pack, it means that there is no connection in the other combination i.e., 2S means 2 cells in series and 0 in parallel and correspondingly, 2P means 2 in parallel and none in series. There are a few terms associated with battery packs in general.

· State of Charge (SoC): This the amount of energy/electrical charge that is left in a given battery. Take a battery that is rated to have 4Wh of capacity an SoC of 35% would mean that out of the 4Wh of energy, only 1.4Wh remain. In EVs, the SoC is generally calculated as a function of energy whereas in case of smartphones and laptops SoC is calculated as a function of electrical charge. Take the 4Wh battery for example, let us suppose it is rated at 3.6V, this would give the battery a nominal capacity of 1.111Ah or 1111mAh and an SoC of say 30% would mean that out of the total charge that the battery can store, 0.3333Ah remain. The SoC of a battery depends upon several factors such as the voltage across its terminals, the instantaneous current, the temperature of the cells, pressure on the cells etc.

· State of Health (SoH): SoH is typically how much the battery has worn out after a given number of charge-discharge cycles. A battery rated for 4Wh might not be able to retain its capacity throughout its life. This happens because of several factors such as corrosion of the electrodes, development of unwanted precipitates inside the cell, thermal damage, dust, water etc. An SoH of 75% in a 4Wh battery means that the battery which could hold 4Wh of electrical energy at 100% SoC can hold only 3Wh now. Typically, a Lithium-Ion battery is considered useful for EVs until it reaches 80% SoH after which its capacity to hold electrical charge degrades too quickly to be used safely in an EV, such batteries are given a second life as inverter batteries in most cases or are recycled for precious metals such as nickel and cobalt.

Now that you’ve developed a rough idea of how Lithium-Ion batteries behave, let’s take a look at how they have to be managed.

A battery management system is essentially what is says it is, a system designed to effectively manage batteries. But how and more importantly why should batteries be managed. (A BMS is sometimes also referred to as an energy management system or an intelligent energy management system by several auto manufacturers)

Some of the functions of a BMS are,

· SoC, SoH measurement

· Offer protection from electrical faults

· Facilitate charging

· Cell balancing

The first 3 functions are pretty straight forward but what is cell balancing and how is it done?

Cell balancing is essential to ensure optimum life of a lithium-ion battery pack and this is simply because not all cells are created equal despite the best quality control processes set up and this may cause some cells to charge/discharge more than others, this results in more wear and tear on some cells than the rest and it reduces performance and can also cause protection circuits to trip.

Cell balancing is achieved in the following ways,

· Active cell balancing: Here the cell with the highest SoC is disconnected from the supply and the rest are allowed to get charged until they reach the same capacity. The key advantage of such a balancing system is that no energy is lost in the balancing process. The disadvantage is that this can only be implemented while charging.

· Passive cell balancing: Here the cell that has the least SoC is disconnected and other cells are discharged to the SoC of this cell. Alternatively, cells can be brought to an SoC which is in between the highest and lowest SoC depending upon the circuit used. In case of the former, the rest of the cells are discharged across resistors until their SoC reaches the minimum value. In the latter, the cells dump their extra charge into capacitor(s) which in turn charge cells that are at a deficit. This method can be used in both charging and discharging conditions but then a minimum of 50% of energy will be lost even in ideal conditions, so this is also generally preferred during charging only. Passive cell balancing is cheaper to implement than active cell balancing that is why low cost EVs generally use this method.

Now, it must be much easier to understand how Lithium-Ion batteries work and why they require fancy electronics to function properly. Do check out the following sources of information.

My published work on Lithium-Ion batteries.

1. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3808494

2. https://ieeexplore.ieee.org/abstract/document/9386861/

Bibliography

1. https://www.google.com/url?sa=i&url=https%3A%2F%2Fcircuitdigest.com%2Farticle%2Fcell-balancing-techniques-and-how-to-use-them&psig=AOvVaw2tcye7_pJPBqoDQD_Ctb9V&ust=1626021551499000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCKDMtL772PECFQAAAAAdAAAAABAD

2. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.ionenergy.co%2Fresources%2Fblogs%2Fcell-balancing-battery-life%2F&psig=AOvVaw2tcye7_pJPBqoDQD_Ctb9V&ust=1626021551499000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCKDMtL772PECFQAAAAAdAAAAABAJ

3. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.digikey.com%2Fen%2Farticles%2Fbattery-cell-balancing-for-improved-performance-in-evs---part-i-passive-balancing-technologies&psig=AOvVaw2tcye7_pJPBqoDQD_Ctb9V&ust=1626021551499000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCKDMtL772PECFQAAAAAdAAAAABAP

4. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.digikey.jp%2Fja%2Farticles%2Fbattery-cell-balancing-for-improved-performance-in-evs---part-ii-active-balancing-technologies&psig=AOvVaw2tcye7_pJPBqoDQD_Ctb9V&ust=1626021551499000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCKDMtL772PECFQAAAAAdAAAAABAV

Battery Management Systems: Uses, Design and Working was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

Since 2021, countless reports of electric vehicles catching fire have emerged raising concerns regarding their safety and roadworthiness in the present era. In India, at least one death has been reported to be directly caused by an EV catching fire that happened in the summer of this year. One Ather 450X, one Ola S1 pro, one Tata Nexon EV and two entire dealerships of Pure EV have caught fires reportedly caused by the battery packs entering into a state called “Thermal runaway”, a state where the temperature rise of the battery pack cannot be controlled at all. This is an extremely dangerous state that must be avoided at ALL costs as it can and sometimes WILL lead to loss of human life.

To understand how EV fires work, one must first make an attempt to understand how fires work in general. Any fire requires three key components to sustain itself viz., heat, fuel and oxygen. The supply of only one of them needs to be cutoff to kill a fire. Most fire extinguishers cutoff the supply of oxygen or heat or both in most cases. The supply of fuel on the other hand, can only be cutoff in certain situations such as fires that involve fuel pipes. Some fires are special in their own way. They generate their own oxygen and do NOT require an external source of oxygen such as air, these fires can get extremely hot in no time and are nearly impossible to control. Some common examples of substances that burn in such a manner are gunpowder, thermite and the elephant in the room, Lithium-ion batteries.

This is the reason why EV fires are so deadly, they generate their own oxygen to sustain themselves and generate extremely large quantities of heat. Adding insult to injury, battery packs are solids (rather solid blocks containing liquids) and its almost impossible to isolate them from the fire. This is a deadly combination and people’s concerns regarding their safety are quite genuine.

The above information might just fan the flames of hysteria that exists against EVs but one must be assured that an EV is much less likely to catch fire than a conventional IC engine vehicle. Let’s look at the numbers here, out of 20,000 Nexon EVs sold by Tata between 2020 and 2022, just one has caught fire and zero people have reported injuries or death. Out of over 50,000 Ola S1 pros sold between 2021–22, just one caught fire and again, no injuries reported. The biggest reason for this is the fact that not a single component of an EV is likely to operate at a temperature beyond 100 degree Celsius whilst on the other hand, any IC engine can easily hit temperatures above 400 degree Celsius (conservative figures, diesel engines hit above 1000 at idle). This coupled with the fact that highly combustible liquids such as petrol are involved, the likelihood of a vehicle fire increases by several fold. In fact for every 100,000 EVs, 52 fires are reported annually in the US for petrol cars, the number is at 1529. This shows that an EV is nearly 30 times less likely to catch fire than a petrol-driven vehicle.

The danger in EV fires isn’t about the likelihood of fire, it’s about controlling and fighting EV fires which is the hard part. Only in the recent past have companies been able to develop fire extinguishing technology to deal with EV fires. (See Aqueous Vermiculite Dispersion (AVD) technology).

One of the common myths surrounding EV fire prevention and control is that this can be accomplished by the BMS. The BMS of a battery pack is incapable of either preventing or controlling a fire because of the fact that once a battery pack hits thermal runaway, there is no turning back for the battery. It WILL catch fire. A BMS can anticipate thermal runaway to a certain extent and can take some preventive action but even this is not guaranteed to completely prevent a fire from happening. Loss of life on the other hand, can be prevented as there is a time delay between a battery pack hitting thermal runaway and actually catching fire and passengers can be given enough warning to evacuate the vehicle. (One of the key reasons why, very few casualties have been reported).

EVs are by several orders of magnitude safer than IC engine or hybrid vehicles. The advent and further advancement of technologies such as AVD will only make EVs safer to use and will make fighting EV fires much easier. With the advent of sodium-sulphur batteries, EV fires may be eliminated all together thereby giving even more peace of mind to EV owners.

As of now, effective thermal management of battery packs, speedy evacuation procedures have already made EVs safer to drive. The automotive industry has also set standards on the quality and type of electronics and power electronics that can be used in an EV to reduce the chances of overheating, short-circuiting and any other factors that may lead to fire.

References

1. https://www.autocarindia.com/car-news/tata-motors-conducting-detailed-investigation-into-nexon-ev-fire-424888
2. https://wattsguerra.com/practice-areas/automotive-defects/what-makes-a-car-catch-on-fire/
3. https://news.abplive.com/auto/are-evs-more-likely-to-catch-fire-than-petrol-cars-1538863
4. https://www.indiatimes.com/technology/news/petrol-vehicles-vs-electric-cars-559242.html
5. https://www.avdfire.com
6. https://economictimes.indiatimes.com/industry/renewables/amid-incidents-of-e-vehicles-catching-fire-companies-charged-up-about-ev-battery-localisation/articleshow/91574065.cms?from=mdr

The burning issue of EV fires. was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

There are a number of ways to describe battery physics like Physical model, Equivalent circuit model, Fractional order model, Blackbox model, etc. But to choose which model will best fit your battery accumulator is quite critical.

The simplest model to adapt for battery physics is the Equivalent circuit model because its numerical simplicity and understanding are quite simple as compared to other existing models. There are different ways to configure the ECM model using different RC pair configurations. Here we discuss the Thevenin model to describe battery physics which is quite a decent model to study. We can use more RC pairs in the Thevenin model depending on the requirement but to make this article simple we are using the 1RC model here.

Thevenin Model (1-RC Model)

Open circuit model (OCV) of the cell is described by the voltage source component in the above circuit and the battery’s internal resistance and diffusion are described by R_int and Rp & Cp component respectively.

Dynamic voltage can be expressed as: -

where OCV = Open Circuit Voltage

Ut = Terminal voltage

R0= Internal resistance

R1= Diffusion resistance

I= Applied current

For Battery state estimation, it is very critical to find the parameters which described good battery physics. The good point of this model is that we don’t need to dissect the cell to find the parameters, it's a non-destructive method which makes this model universally acceptable. There are different numbers if ways to find these RC parameters like OKID-ERA, State-Space, Subspace, transfer function, etc. but here we are going to discuss how we can estimate those parameters using the transfer function system ID

The transfer function model can be described in many ways depending on the noise and disturbance. For measurement noise in the system we use Output Error model and for process disturbance in the system we use ARMAX model and for both noises, we use Box-Jenkins models, and for the less complex system, we as a Grinntech Motors sometimes use ARX model for real-time parameter estimation which is very much related to output error model to tackle the voltage sensor noise and here we are going to discuss the ARX model which is less numerically complex and quite simple to implement.

ARX model is described as

where w is measurement noise, x is applied current and y is your terminal voltage.

ARX Model

ARX Model equation is expressed as: -

y(k) = G(q)*u(k − n) + w(k),

G(q) = B(q)/ A(q)

A(q) = 1 + a1q−1 + a2q−1 + ··· + akq−n

B(q) = b + b1q−1 + b2q−1 + ··· + bkq−n

The battery equation can be expressed like an ARX model equation to find the regressor vector(G) and output vector(Y) which can be expressed as

Y=G*X

We do the slow rate charge-discharge and dynamic testing like the UDDS cycle, HPPC cycle, at Grinntech Motors facilities to acquire enough data to understand the relationship between SOC-OCV and dynamic behavior of the cell concerning dynamic load current as expressed in the dynamic voltage equation(Eqn-1).

Once you choose the best fit model for your system just like we did here use the ARX model for your system and do the bilinear transformation to find the relationship between the regressor vector, output vector, and parameter vector.

The below equation is expressed for 1RC Transfer function model for your reference

Once we have enough test data we can form a regressor and output matrix similar to the matrix mentioned in the above equation, the above equation varies based on the number of RC pair you want to identify. Once you form the regressor matrix and output matrix we can easily identify the parameters(X) using the least square method. The least-square method which is based on linear algebra projection is one of the most common methods to identify the unknown parameter.

Once we get the parameter vector(X) is just a matter of solving the equation to find the internal resistance and RC parameters. As we know the internal resistance and capacity vary over calendar and cycle life, so it is very important to identify these parameters in real-time for good state estimation and using the transfer function model and adaptive method of the least square i.e. recursive least square method we can tackle that problem and as before it is not that complex as compared to other optimization and identification techniques for your controller to process, that is one of the main reason why we use this model to identify the parameters in real-time and the other method that we will discuss later which is quite useful to find the best first guess parameters for our battery without any non-linear optimization. Note to make this article simple enough for people to understand we have not included the hysteresis model in this very article and I tell you this in advance this very concept is a base for battery health estimation.

Stay tuned for a future article related to this field.

Some Techniques for Battery Parameter Identification was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

Lithium-ion cells and batteries has become an important part of our life. Almost all of our battery powered devices like Mobile, Laptop, Music Players etc. are powered by Li-ion cells. This dependency is only going to increase with mainstream adoption of electric vehicles all of which are powered by Li-ion batteries again.

One of the primary reason for such a high acceptance of Li-ion technology is it’s long life. These batteries can last anything from a year to a decade depending on the application. Although slow, like any other battery these batteries also degrades over time. In this article we will be talking about different mechanisms of cell degradation.

Some of the factors that causes or accelerates degradation are as follows.

1. High temperature operation
2. Uncontrolled fast charging
3. Uncontrolled fast discharging
4. High voltage operation (over charge)
5. Low voltage operation (over discharge)

When we peek inside these degradation mechanism at chemistry level there are two main factors (although there are many more).

1. SEI Layer Formation

2. Lithium plating

SEI Layer Formation

Anode material such as graphite whose potential is below 1.1V tends to react with the electrolyte which is commercially used in Lithium-ion cells, for example, Ethylene carbonate because of its instability of potential below 1.3V. This incompatibility allows the electrolyte to react with a negative electrode and form an irreversible product like lithium carbonate, lithium bicarbonate, (Li2CO3, LiF, Li2O), and consume lithium in the process.

For a better understanding of SEI layer consider SEI layer as corrosion. Once it’s first layer is formed, it won’t easily allow electrolyte to react with a negative electrode and that’s the reason we operate the cell at very low C-rate during its first cycle so that it will consume less lithium to form a thin layer of SEI and the same formed SEI layer act as a barrier between negative electrode and electrolyte. But it won’t stop the SEI layer formation completely because of mainly two reasons

First: Because of porosity in the layer which allows the SEI layer to form but at a slow rate which leads to cell degradation over time.

Second: During the intercalation or De-intercalation of lithium-ion leads to micro cracking in the SEI layer due to contraction and expansion on the surface. Similar to corrosion when there is a crack in the layer it will fill the void with a new SEI film and in that process, it will consume new lithium-ion.

Along with these two causes, there are other causes too which can highly accelerate SEI formation like operating the cell at a high temperature which leads to the dissolution of SEI or fracture due to mechanical stress

Unlike low potential negative electrode, there are other negative electrodes which operate at high potential like LTO, because of this high potential window we can mostly avoid SEI layer formation. This is one of the main reason why LTO have higher life than other cells. But it has its limitation, due to low overall cell voltage it has less energy density.

In 2000s lot of paper were published on the SEI layer formation and cell degradation

The models were developed to track the SEI growth and capacity loss and resistance increase due to SEI.

The Side reaction expressed as

Solvent(EC) + 2Li+ + 2e- = Product (Lithium carbonate, Li2CO3, LiF, Li2O, etc)

The kinetics of this irreversible side reaction can be described by the Tafel equation.

Lithium plating

Now let’s talk about other main reason for cell degradation, Similar to the SEI layer, low potential negative electrode cause rapid lithium plating as compare to the high potential negative electrode.

A high charging rate is one of the main reasons for lithium plating due to lithium limitation on the surface of the negative electrode.

Due to the rapid intercalation of lithium-ion on the surface of the negative electrode, negative electrode gets saturated and the excessive lithium-ion trying to intercalate but no place to go, get plated into lithium metal because of its high kinetic energy. This lithium metal accumulated on the surface and edge of the negative electrode and consume lithium-ion on the process.

Lithium metal accumulated on the negative electrode reacts with electrolyte to form lithium carbonate or other irreversible by-products. This layer act as a barrier between lithium and electrolyte to prevent the formation of new irreversible products. This side reaction can lead to high capacity loss and electrolyte degradation. Operating at low temperatures can also lead to rapid lithium plating.

With the continuous fast charging, more and more lithium metal tends to accumulate on the surface of the plated lithium and form a dendrite structure. This growing dendrite structure of lithium metal penetrates the separator and short the positive electrode and due to its high conductive property, it causes an internal short circuit which either leads to dendrite fuse or thermal runaway due to high heat generation.

Li-ion Cell Degradation Mechanism was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.

Li-ion, is considered to be one of the most sophisticated pieces of technology in energy storage right now. It is also the most commercialized technology for its cost to performance ratio.

Expectedly, for such a versatile and widely used technology, there is a lot of misleading information. These are usually a result of ill researched facts, often undertaken by the marketing department of companies, who are largely or wholly restricted to working with a certain kind of battery chemistry. Subsequently, this results in the sharing of half — truths or sometimes, even outright wrong claims, which instead of providing clarity, creates further fogginess in the minds of the end user!

In this series, we will try to understand the full picture of Lithium-ion battery safety and their co-relation to its chemistry.

Different Chemistries in Lithium-ion Family

What we call Li-ion is actually a family of Chemistries. They differ by Cathode material (mostly) or by Anode material. There are major variations which should be included in Li-ion family or not is debatable, and then there are minor or very custom variations made for very specific purpose and majority of people are not even aware of those.

For the sake of simplicity we will limit our discussion to most common Chemistries which are well known and commercialized by multiple companies. These are

• NMC (Nickel Manganese Cobalt)
• LFP (Lithium Ferro Phosphate or Lithium Iron Phosphate)
• NCA (Nickel Cobalt Aluminium Oxide)
• LMO (Lithium Manganese Oxide)
• LCO (Lithium Cobalt Oxide)
• LTO (Lithium Titanate Oxide)

We will also occasionally talk about Chemistries or technologies outside of this list, mostly for making a point.

How Lithium-ion Cell Works

To understand the Li-ion battery safety concerns, we need to understand how these batteries works at cell level.

Without going in too much of detail, what we need to understand from above image is that when we are discharging the cell, the Lithium ions move from Anode to Cathode through electrolyte while the electrons move in same direction but through the external circuit (the load). While charging, the reverse occurs with Lithium ions and electrons moving back to Anode.

Lithium-ion cell components

Li-ion cell is made of (although not limited to)

• Cathode: NMC, LFP, LMO, NCA, or LCO
• Anode: Carbon (In Graphite form) or LTO
• Separator: Ceramic or similar material
• Electrolyte: Lithium salt (e.g. LiPF6), in organic solvent (e.g. Ethylene Carbonate)
• Current Collectors: Aluminium and Copper

Lithium-ion Safety Concerns

Li-ion cell safety is compromised when any of the above mentioned components gets damaged or becomes unstable.

Any safety breach leads to a sudden release of stored energy raising the cell temperature to extremely high levels, a phenomenon, which is called, “thermal runaway”. This heat energy then reaches nearby cells pushing them into thermal runaway. It creates a chain reaction, jeopardizing the safety of the complete battery pack and ultimately can result in a fire hazard.

We will look at some of the major safety breaches and how they are related to chemistry of the cell.

Cathode Material Disintegration

Common Materials

Common cathode materials are NMC, LFP, LMO, NCA, and LCO. What is notably missing from this list is LTO because that is an Anode material. When we have an LTO battery, the Cathode will still be any of the common ones, although NMC and LFP are most widely used.

Failure mechanism

It is a well-known fact that cathode materials start to become unstable at high temperatures. This is called thermal runaway temperature and the temperature threshold is different for each chemistry, as seen in the table below:

As can be seen, the LCO and NCA are having lowest thermal runaway temperature of 150 degrees centigrade. When a cell starts heating, (either because of thermal runaway of nearby cells or any external heat source or high current draw), these chemistries will be the first to start disintegrating and going into a state of thermal runaway. On the other hand, LFP has the highest thermal runaway temperature of 270 degrees centigrade. This makes it the safest Cathode material. LMO and NMC are midway at 250 degrees and 210 degrees centigrade, respectively.

This is the reason, why LFP is advertised to be the most safe Lithium-ion chemistry but it overlooks a lot of important factors. Let us understand what those are.

Factors overlooked

Safety of LTO Battery: LTO batteries are considered to be the safest of all Li-ion batteries. LTO batteries have NMC for their Cathode material and LTO is the Anode material. Even with NMC in place these batteries are extremely safe. This tells us that most accidents with Li-ion batteries are not related to Cathode material. Instead the stability of the Anode material, plays a much bigger role, and here LTO makes it much safer than Graphite.

Energy density: Energy density plays a big role in the safety of the battery. It is not hard to understand that more energy is released, from these high energy density cells, in the event of a thermal runaway. This high amount of energy increases the probability of a nearby cell reaching their thermal runaway temperature threshold. This can be understood from the fact that any cell chemistry, which fails the “nail penetration test” at full charge condition, passes the same test in a partially charged state. Partially charging a cell, in a way, is making it a low energy density cell. This is the reason why LTO and LFP are so safe, as they have much lower energy density of 70Wh/kg and 120Wh/kg respectively, when compared to 250+Wh/kg for NMC and others.

Conclusion

To conclude, we can say, that for a cell to go into thermal runaway, the deciding factors are:

i) The temperature at which the Cathode material will start disintegrating

ii) The amount of energy the cell is holding, as this will tell us the probability of propagation of thermal runaway in the adjacent cells.

If all other factors are same, LFP is the most stable Cathode material and LCO/NCA, the least stable. But this is only, half of the story. The much bigger factors are the stability of the Anode material and the energy density of the cells. These factors ultimately overshadow the advantage of LFP and dictates the overall safety of the battery.

In part 2 we will talk in detail about the safety risk associated with the Anode materials.

Myth-buster: Lithium-ion Battery Chemistries and Safety — Part 1 was originally published in Grinntech on Medium, where people are continuing the conversation by highlighting and responding to this story.