EV Battery Tech : Charging vs Swapping

Currently neither charging station nor swapping stations are in enough numbers to see greater EV adoption.

BHPian Sarath_ recently shared this with other enthusiasts.

We look at electric cars today like we look at babies. We see their potential and know they are the future.

Currently neither charging station nor swapping stations are in enough numbers to see greater EV adoption. More EV adoption will see more EV stations leading to a chicken and egg situation.

However which particular model is better in your opinion?

A charging station in basement, office and accessible local fast chargers or a battery swapping station?

Indian government has released some standard for charging stations or EVSE as they are mentioned and also plans for standards for battery swapping (easier for bikes than cars).

Electric vehicle supply equipment (EVSE) is the basic unit of EV charging infrastructure. The EVSE accesses power from the local electricity supply and utilizes a control system and wired connection to safely charge EVs.

INDIAN STANDARDS FOR BATTERY SWAPPING

Separate projects have been initiated for battery swapping standards for LEVs and buses. They will be two series of standards documents, covering the form factor of the battery pack, inter-operable connection systems, communication between the battery management system (BMS) and the EV and charging station, and network management. Any EV may utilize a battery pack conforming to these standards. The removable battery packs can be charged using AC or DC charging systems. The BIS is yet to develop Indian standards for EV roaming and grid-related management functions.

CHARGING

Pros

• You own the battery pack and will not have to deal with uncertainties of receiving a faulty one failing on your journey
• Charging at your own pace in your basement / garage / office parking is convenient and does’t require you to add another task to your daily inventory
• Most of us do not need a full charge for our daily needs, slow charging and partial battery capacity increase longevity of the battery
• The battery is designed along with the chassis thus making it an integral part of the overall car, thus also adding to the safety, efficacy and rigidity of the car

Cons

• Expensive – The battery is a huge portion of the overall cost of the EV and in our markets the cost cutting starts in there thus giving us small range
• Heavy – The battery is a heavy and adds a huge load to the car, increasing the dry weight. Improper to use the term dry weight but even at the end of your charge you are still carrying the exact weight of a newly charged car.
• Updates – Battery technology is progressing very fast. You could end up with a battery that is outperformed by a newer commercial battery in 3-5 years and you can do nothing but wait for your car to reach the end of its service life for an upgrade
• Degradation – Batteries degrade and you would end up with a car that depreciates not only in value but also in function making it seem like it is actually organically aging with you
• End of life usage - What do you do when your car is perfectly fine, the motors, transmission, electronic etc but only the battery is dead. An expensive retrofit with a new battery or junk the entire car adding to e-waste

BATTERY SWAPPING

Pros

• Affordability - You buy a car without a battery and that reduces the overall cost of ownership. Faster adoption and making EVs more accessible.
• Risk aversion – A faulty battery recall will not affect you as you never owned one in the first place, You will always get a battery that you can use but don’t have to worry about after the next swap.
• Upgrades – Any new battery technology is immediately accessible since all batteries are standardised according to Indian guidelines (in the future). You would have access to the latest and greatest, a lighter battery or maybe one with more range, a cheaper option for your reduced usage perhaps.
• Charging infrastructure –You do not have to worry about the charging infrastructure in your own basement or office and petition for EV charging spaces. And if there already are you can use it to top up your battery.
• Weight – There could be options for smaller batteries with dead spaces in between them if you do not want the full 500km range thus saving on weight and energy (I have not seen any real world application of this idea – just my thought)

Cons

• Quality – The battery quality will always be in limbo. You might never be able to trust the incoming battery regards to safety and efficacy
• Range – The incoming battery might not have the same range as your previous one. It will always be different for each battery, adding a tinge of uncertainty for any planned trips
• Extra components – Your car will require extra components for the battery swapping mechanism to work thus adding to more components that can fail. Any step that adds complexity will lead to more problems.
• Safety issue – Any problems that arise will be a nightmare to solve. Did you battery pack catch fire? Was it the car manufacturer whose motors are not working properly? Was it the battery pack provider who supplied you with a faulty one?
• Expensive – You are in effect renting a car equivalent when it comes to cost of the battery packs. It will not be cheap to rent. The infrastructure will be very expensive and hence sparse leading you to drive long distances in a hunt for a short battery swap.
• Incompatibility – A 3 wheeler has no use for a large battery. Similarly a MUV will not have use for a battery pack that goes into a small hatch. Any size that you fix upon will have trade-offs and compromises for different parties. Making different sized swappable battery packs will only increase cost and complexity.

I do have to mention that even Tesla gave up on the battery swapping technology for reasons unknown but could be related to complexity and economics.

Some startups are trying their hand on the technology.

Here's what GTO had to say on the matter:

Charging any which day! And I feel this will be the case for most personal EV owners, worldwide. Reasons:

- Charge your car like you charge your phone. While parking overnight! That's the best time to charge.

- I take care of my cars & would prefer owning my well-maintained battery over running an abused, public battery in my car.

- 500, 700 & even 800 km EVs will come soon to India (Tesla already has a ~650 km long-range EV). I don't need anymore range than that.

- For the times that I go on long road-trips, I will charge while me & family get a meal. 30 - 60 minutes is a good top-up at fast-charging stations.

Battery swapping is messy & complicated. With battery tech fast progressing, it'll become an irrelevant solution, except for those who need to keep their vehicles running 24x7 (e.g. commercial vehicles).

Here's what BHPian raghupro had to say on the matter:

I would prefer charging at home, which would be the case on 99% of the days as I barely travel once per quarter or so on highways.

What I would rather prefer is an option to store my vehicle's battery in a swapping station, upgrade to a higher capacity battery for a long trip, come back and re-swap the battery with my own battery. More so like a battery bank where I can store my vehicle's battery and get it back again. Would be cool to have such a facility in the future.

Here's what BHPian StarrySky had to say on the matter:

I wouldn't necessarily rule out swapping as an option.

If the battery is basically on lease, it can bring down the cost of buying an EV. Thereafter, swapping or not is up to me. Nobody is forcing me to swap during daily use or during long trip - unless manufacturers force my hand somehow, either by providing dead slow DC charging, or having specific clauses demanding that batteries should be swapped at least once in X months or so on.

After 5 or 6 years, if I start seeing some serious degradation on the battery, I can then start swapping when needed. But then an interesting question is, how the degradation is handled? Do I, as the user of the battery, have to make sure that when I return the battery it has atleast, let's say, 95% of the capacity it had when I started my lease? That would force me to swap often.

Read BHPian comments for more insights and information.