Some thoughts after 10 years of me driving and living with EVs. They do pretty much everything we need them to do (save for fully support pull through towing). We still need better infrastructure, but that's coming. Purchase cost is still an issue. But I think there is really just one major issue that hasn't been dealt with or that doesn't have a clear solution yet.
The primary issues with EVs I think is concerns over how long the expensive batteries will last. If you think you will have to replace a $20K battery every 5 to 10 years, or if you really do, that's a huge problem for the long term prospects of EVs.
What do we know about the batteries at this point?
There is battery degradation, but it's reasonable. As long as you get a battery that is maybe 20%-30% more than you need, it will be sufficient long term.
Occasionally, a battery pack can fail, requiring a battery replacement. This is where the real problem is. Not degradation. But what are the frequency of failures, and how does that frequency change over time? Are the failures typically one cell that goes bad, or are all of the cells going bad just at different rates? These things we don't quite know (do we?).
What are acceptable long term maintenance costs?
We are off to a good start in that most EVs today come with 8 yr warranties on the battery systems. This gets us past paying off loans, after which we should be capable of affording expensive service if needed (or you can switch cars before the 8 yrs is up).
But I don't think it's good enough. It's still a major sore spot for EV value and adoption.
In general, I would think you would probably want a vehicle battery pack to last a confident 20 years. But thinking about this more deeply, we can come up with a metric. If a $20K pack should last 20 years, you could instead say long term maintenance costs on the battery systems should be less than or equal to maybe $1K per year. Is that reasonable? Or is that still too high? Should it be $500 per year? Coming up with this type of metric can help us figure out what solutions are acceptable for future EVs.
Achieving an acceptable service profile for EV batteries I think can go any number of ways.
1) Battery packs that are reliably lasting long enough to meet the service cost criteria.
2) Battery packs that are more modular and serviceable in way where battery costs will typically be smaller service or module replacements that cost a lot less than entire battery replacements. If a battery has a bad cell and is serviceable, you get that one cell or module replaced and get the vehicle back on the road, replacing only the parts that have actually failed. A lot of the cells in a bad pack are probably still fine.
3) Battery packs that are treated as separate products from the actual vehicle. This would open up options like being able to buy the car but lease the battery, or longer term service contracts for batteries (instead of a Tesla 8 yr 100K mile battery warranty, it could be a 20 yr unlimited mile service contract)
Furthermore, it would be a good idea to build battery architecture in a way where DIYers are generally sufficiently safe and capable of doing their own battery service. With some diagnostics assistance from software or readers, a DIYer should be able to determine what cell or module is bad, order a new one, disengage the contactors for the battery and the bad module, and replace that module themselves. This would put it on par with gas car repairs, and would probably make service visits cheaper too when having someone else do it.
I feel like we are headed more towards an option 1, but I would probably prefer option 2 or 3, as option 1 still comes with the bad luck lottery where some folks will have batteries that fail early.
Where do you think we need to be?
The primary issues with EVs I think is concerns over how long the expensive batteries will last. If you think you will have to replace a $20K battery every 5 to 10 years, or if you really do, that's a huge problem for the long term prospects of EVs.
What do we know about the batteries at this point?
There is battery degradation, but it's reasonable. As long as you get a battery that is maybe 20%-30% more than you need, it will be sufficient long term.
Occasionally, a battery pack can fail, requiring a battery replacement. This is where the real problem is. Not degradation. But what are the frequency of failures, and how does that frequency change over time? Are the failures typically one cell that goes bad, or are all of the cells going bad just at different rates? These things we don't quite know (do we?).
What are acceptable long term maintenance costs?
We are off to a good start in that most EVs today come with 8 yr warranties on the battery systems. This gets us past paying off loans, after which we should be capable of affording expensive service if needed (or you can switch cars before the 8 yrs is up).
But I don't think it's good enough. It's still a major sore spot for EV value and adoption.
In general, I would think you would probably want a vehicle battery pack to last a confident 20 years. But thinking about this more deeply, we can come up with a metric. If a $20K pack should last 20 years, you could instead say long term maintenance costs on the battery systems should be less than or equal to maybe $1K per year. Is that reasonable? Or is that still too high? Should it be $500 per year? Coming up with this type of metric can help us figure out what solutions are acceptable for future EVs.
Achieving an acceptable service profile for EV batteries I think can go any number of ways.
1) Battery packs that are reliably lasting long enough to meet the service cost criteria.
2) Battery packs that are more modular and serviceable in way where battery costs will typically be smaller service or module replacements that cost a lot less than entire battery replacements. If a battery has a bad cell and is serviceable, you get that one cell or module replaced and get the vehicle back on the road, replacing only the parts that have actually failed. A lot of the cells in a bad pack are probably still fine.
3) Battery packs that are treated as separate products from the actual vehicle. This would open up options like being able to buy the car but lease the battery, or longer term service contracts for batteries (instead of a Tesla 8 yr 100K mile battery warranty, it could be a 20 yr unlimited mile service contract)
Furthermore, it would be a good idea to build battery architecture in a way where DIYers are generally sufficiently safe and capable of doing their own battery service. With some diagnostics assistance from software or readers, a DIYer should be able to determine what cell or module is bad, order a new one, disengage the contactors for the battery and the bad module, and replace that module themselves. This would put it on par with gas car repairs, and would probably make service visits cheaper too when having someone else do it.
I feel like we are headed more towards an option 1, but I would probably prefer option 2 or 3, as option 1 still comes with the bad luck lottery where some folks will have batteries that fail early.
Where do you think we need to be?
