Electric Vehicles, Part 3

I asked on Instagram about what questions you have on electric vehicles. Here are my answers

“Is an EV I buy now going to be as good as one I buy in 10 years?”

I assume this question is mostly aimed at the battery. Electric vehicles are in some ways much simpler than conventional cars because they are a battery and a drive-train. They usually have less maintenance costs, but the upfront cost of the battery is what makes them so (prohibitively) expensive [1].

Near future (within the decade): Lithium ion batteries are likely to dominate the market for at least the rest of the decade; the costs of a lithium ion battery have already come down significantly [1]. Really there are several metrics that get optimized in the design of an EV battery: they could make cheaper batteries, but at the reduction in lifespan, range on a single charge, or weather resilience. Likewise, they could make a car that goes further and has a longer battery life, but it would cost more or weigh more. Assuming drivers require a good range (300 miles), a good lifetime (10-15 years), and good weather resilience (among other reliability and safety standards), how much could the cost still come down?

Sakti 2015 [2] shows that the costs come primarily from materials and the material costs come primarily from electrode active materials. Labor is less than 5% of the costs overall, so batteries reach economies of scale really quickly and have already benefited from learning curves as the manufacturing processes developed. EV batteries need to reach 100-125 $/kWh to be cost competitive with gas cars [1] [3]; getting at least close to this goal is potentially realistic (depending on how you count the costs), but the current technology can’t get significantly cheaper than that.

Image Source: Sakti 2015 [2], Breakdown of the cost of a battery inside a plug-in hybrid electric vehicle.

Other battery technologies show potential for a major battery breakthrough that launches us into a more energy-dense era for batteries; however, a breakthrough like this will almost definitely not impact the car industry within the decade. After that, who knows? I’m sure there is a yet-undiscovered technology that will really change the game. I just don’t think lithium ion batteries will get there through marginal improvements in production, efficiency, or chemistry. I think that there will eventually be strides in battery technology, but I don’t think it will impact the car market any time soon in terms of dramatic price reductions or range expansions.

“How do people without access to a garage charge their car? This seems like an equity issue…” (Question from my Grandma!)

Great question. I think this is a huge issue that hopefully state and federal governments will tackle, because if you require people to have zero emission vehicles, you also need to provide a way to charge them. Right now most people I’ve talked to express range anxiety about long road trips, but I think the more pressing issue is the lack of charging right outside their apartment! I couldn’t get an EV right now because I rely on street parking and have no close access. Traut et al 2013 really highlights this by showing that only about 47% of car owners also own their parking spot (as opposed to renting) and only 22% of vehicle owners have their parking spot within reach of an outlet [4].

“Possibilities on what to do with the battery?” (I assume this question means second-life)

This is a really interesting question too!

You can re-use, directly recycle materials, or basically melt down the components (either by heat or chemically) to extract raw materials to make new batteries.

Re-using a battery would be taking the EV battery and using it for a different application, like storing energy from your solar panels. Batteries don’t just go from good to bad, they slowly lose range. A battery could provide half its original range and not be sufficient to meet driving needs, but work very well for a different application (Harper et. al [5]).

Even if batteries get a second or third use, eventually it will hit its end of life.

Harper 2019 explains that EV battery recycling can basically be split into two larger groups that I’m calling direct recycling and metals reclamation. In direct recycling, the components are taken apart and the cathode is re-used (and probably replenished). This method in some ways is most energy efficient, but the problem is that electric vehicle batteries aren’t standardized in their shapes or chemistries, which makes this option not very viable right now. It also has limited returns as the battery gets really old and degraded. If the battery is just melted down and separated into its raw metals through chemistry or high heat, the battery doesn’t need to be taken apart to the same degree; this method can use a lot of energy and labor. Currently the raw materials are cheap enough that recycling isn’t worth the cost to do it compared to just extracting more [5].

It would be nice if battery shapes and chemistries were a little more standardized for the purpose of recycling. I also think as more electric vehicles hit the road, more will eventually hit end of life and recycling will become more necessary.

“How does the cost of charging compare?”

EV’s are a lot cheaper to charge. Electricity is cheaper than gasoline and also less sensitive to global factors like oil cartels, pandemics, and recessions. The difference varies, but my back-of-the-envelope math puts it at about a third of the cost if electricity is 10 cents/kWh and gasoline is about 2.90 $/gallon. Will you make up the cost difference over the life of the car by saving on gas? I think it depends on a lot of factors and isn’t super predictable. For example, the pandemic caused me to stay at home all day and also caused the price of gasoline to drop. I spent way less on gasoline than I would have anticipated in a projection.

Additional cost point, EVs are much simpler than combustion cars; they’re basically a battery and a drive train. The reason they are expensive is the battery. Combustion engine cars can have costly maintenance fixes over its lifetime surrounding the engine, etc. Some of those costs are avoided with an electric vehicle too. Batteries can’t be fixed as easily as combustion engines. If there is a serious problem with the battery and it’s out of warranty, a new battery is a substantial portion of the cost of the car.

References:

[1] Ciez, R.E., Whitacre, J.F., 2017. Comparison between cylindrical and prismatic lithium-ion cell costs using a process based cost model. J. Power Sources. https://doi.org/10.1016/j.jpowsour.2016.11.054

[2] Sakti, A., Michalek, J.J., Fuchs, E.R.H., Whitacre, J.F., 2015. A techno-economic analysis and optimization of Li-ion batteries for light-duty passenger vehicle electrification. J. Power Sources 273. https://doi.org/10.1016/j.jpowsour.2014.09.078

[3] Schmuch, R., Wagner, R., Hörpel, G., Placke, T., Winter, M., 2018. Performance and cost of materials for lithium-based rechargeable automotive batteries. Nat. Energy. https://doi.org/10.1038/s41560-018-0107-2

[4] Traut, E.J., Cherng, T.W.C., Hendrickson, C., Michalek, J.J., 2013. US residential charging potential for electric vehicles. Transp. Res. Part D Transp. Environ. 25. https://doi.org/10.1016/j.trd.2013.10.001

[5] Harper, G., Sommerville, R., Kendrick, E., Driscoll, L., Slater, P., Stolkin, R., Walton, A., Christensen, P., Heidrich, O., Lambert, S., Abbott, A., Ryder, K., Gaines, L., Anderson, P., 2019. Recycling lithium-ion batteries from electric vehicles. Nature. https://doi.org/10.1038/s41586-019-1682-5