Published on June 19th, 2014 | by Christopher DeMorro


Toyota Researching Solid State Batteries As Next Step For EVs

June 19th, 2014 by  


While Toyota might be betting big on hydrogen fuel cell vehicles, they haven’t ceased their research into electric car batteries either. In the long term, Toyota sees lithium-air batteries as the solution to EV range anxiety, but in the interim, solid-state lithium-ion batteries could be a stepping stone towards longer-range batteries.

Charged EVs reports that Toyota has already developed a prototype solid-state battery with an energy density of 400 Wh/L, which is less than half the density of lithium-air batteries, but still better than current lithium-ion batteries. Solid-state batteries also do away with the liquid chemical solution batteries currently rely on, replacing them with a solid electrolyte between the cathode and anode.

The design also allows for battery packs that eliminate the space between individual cells, packing more power into a smaller package. These solid state batteries are also supposed to have a longer lifespan, which means less concern about the longevity of electric drivetrains.

So far though, Toyota has only installed a solid-state lithium-ion battery on an electric scooter, though they say by 2020 these batteries could be ready for the road. Meanwhile, lithium-air batteries are might not be ready until 2030 or later, making this a natural stepping stone between two emergent technologies.

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About the Author

A writer and gearhead who loves all things automotive, from hybrids to HEMIs, can be found wrenching or writing- or else, he's running, because he's one of those crazy people who gets enjoyment from running insane distances.

  • stanson

    Lithium air offers tremendous potential and I applaud Toyota for pursuing that technology.

    On another note, I wish people would stop using the term “range anxiety” since it trivializes a legitimate concern. There are times I need to drive my car long distances and would not be willing to stop for long periods of time to recharge. It’s not “anxiety” and until we can find ways to enable long trips via electric vehicles, the technology will not be embraced by the masses.

    • Bob_Wallace

      What’s a long trip to you?

      Would your life be significantly harmed if you had to stop for 20 minutes 2x on a 600 mile driving day? How long would you otherwise stop for fuel/food/coffee/peeing on those days?

      How much would your life be improved by not having to stop at gas stations during your periods of normal driving? Do you figure you spend more time filling your fuel tank during normal periods of the year than you’d have to give up on long driving days with an EV?

      • stanson

        Stopping for 20 minutes on a 600 mile day would be fine because as you stated it’s not much different than today’s ICE model. However, I don’t see that technology in the marketplace today for a comparable electric vehicle (size and price). Until we do, the masses are going to shy away from electric vehicles.

        • Benjamin Nead

          You make a 600 mile commute to work each day, stanton? Seriously: you’re probably like most folks and drive less than 60 miles per day. If so, you DO have a classic case of range anxiety!

          • stanson

            Had you read my post, Benjamin, you would see where I wrote “there are times I need to drive my car long distances”. How you interpreted that as meaning I have a 600 mile commute to work each day is beyond me.

            The point of my post is that today’s EVs don’t offer people a solution for those times (apart from not taking the trip). So it’s not “anxiety” it’s an unmet need.

            When EVs are available that can handle these kinds of trips at reasonable prices, we’ll see drivers switching en masse and I’ll be in the front of the line.

          • Benjamin Nead

            Well, the reason I phrased it that way is because I’ve talked to numerous people who mention these long distance trips as an impediment for owning an EV and, upon further investigation, find that they only take such long distance trips once or twice a year. Investigating further, many of these same people have work commutes and/or typical daily range requirements of 30 miles or less.

            So, (hypothetically here,) if you move the belongings of your entire house once every 7 years or so, do you buy an 18-wheeler for your daily driving needs, just so you’ll have that extra cargo-carry capacity for the inevitable house move? Probably not. You, more logically, rent a large truck for that specific once-in-seven-years occasion and have a more normally proportioned vehicle for the far more common driving activities of fetching the groceries, doing the work commute or driving the kids to school.

            Likewise, if these 600 mile road trips are a once or twice a year occurrence and you seldom drive more than 30 or 40 miles on any given day, you could probably do well to own an EV and rent a long haul vehicle when needed. The savings you would generate on a daily basis (most EVs can operate at about 2 to 3 cents per mile) would more than pay for the cost of renting a long range vehicle every 6 months or so.

            The key to all of this is taking an honest inventory of your real world driving range requirements. If you really do 100 mile daily work commutes (this seems to be a de rigueur Californian sort of thing that almost nobody else in the rest of the U-S subjects themselves to,) then, yes, you probably would be wise to wait for a longer range EV. Reasonably priced examples of these will be here soon enough.

        • Bob_Wallace

          Two times in 600 miles.

          Tesla says that they will market a 200+ mile EV by 2017 (IIRC) that will sell for around $40k. $40k is not $25k but when one calculates the operating costs of ICEVs and EVs then $40k is competitive with $30k gasmobiles.

          I agree that the masses won’t jump on the EV bandwagon until prices are better but we’re getting there.

          Right now a lot more people should be purchasing limited range EVs like the Leaf. Households with two or more cars could probably use an EV for their longest commutes and an ICEV for the occasional long drive. The Leaf, after rebate, is a $20k car.

    • ThinkOUTsideTheBOX

      Instead of worrying about long range batteries … Currently
      Instead have the dealership have small aerodynamic trailer with highly efficient generator that you rent for ” FREE” with a high credit card deposit ( basically… the cost to replace it… Like part stores do on some tools) make it narrow enough to roll in a motel door at night when you stop at night.
      Individuals are already doing things similar to this on their own .

      • Bob_Wallace

        Seems to me that car companies are expecting long range EVs in the near future. If they weren’t then there would be a lot more PHEVs like the Volt and fewer EVs.

      • Keef Wivaneff

        Right, so you tow a big ENGINE in a trailer behind your electric car?
        Wouldn’t it be simpler to just go and buy a car with an engine?

        • Bob_Wallace


          If you need that trailer fairly often then you would probably be better off with a PHEV.

          If it’s once or twice a year then a range extending trailer might make more sense. And it wouldn’t need be a big engine. Just enough to turn your EV into a hybrid. The batteries are already there to deal with acceleration and braking.

  • Benjamin Nead

    I think the big news here is that Toyota, who with so many hydrogen fuel cell pronouncements as of late and having been so publicly recalcitrant in regards to the future of traction batteries of any type for cars, may be on the cusp of developing one of the better battery compositions.

    There are several companies working on solid state batteries, actually. Moving away from a liquid electrolyte inside the battery cell means a lighter weight, more compact battery that doesn’t require yet another liquid: the cooling fluid surrounding the batteries in thermal management systems found on many EVs that are required to keep the batteries operating within a narrow temperature range.

  • JamesWimberley

    Lithium-air batteries “might not be ready until 2030 or later”? That’s not a plausible rate of innovation in a competitive marketplace: 16 years from now. For comparison, it took 14 years from the first jet aircraft to fly in 1939 to the first supersonic jet fighter in 1953, a greater technical challenge I would have thought.

    • Doug Cutler

      Lithium-air would be a gas tank killer for sure. One big problem is getting the recharge cycles up to anything useful. Researchers believe in time they will find a way but we’re ultimately dealing with the laws of physics here. Just like the limit on the speed of light there will be natural limits for all of these chemical processes. We’re just not sure where they lie until all combinations of matter and chemistry are attempted. There’s no guarantee that lithium-air issues will be solved in a practical way.

      The research on solid-state lithium seems much further along. What I’ve read is 3X range per volume at 1/2 cost per kwh. This is not yet head to head with gas tank capacity but would certainly make EVs considerably more viable.

      • loebner

        Simply remove the battery with a freshly charged one and recharge the removed battery while it’s “off line.”

        Just design the car so that it’s battery can be replaced in about a minute. Surely not a big problem.

        • Doug Cutler

          Telsa has already plans to implement a battery switch-out system. However, it will cost about the same as a gas fill-up compared to their mostly free recharge service. Switch-out can be done with current lithium-ion tech.

          That still doesn’t solve the problem with the current low life cycle recharging of lithium-air. A battery that fails after only 400 recharge cycles is still not practical even if it is in the switch-out loop. Researchers will be trying to get lithium-air up to 1000+ recharge cycles. We wish them every success.

          • loebner

            Of course it solves the problem. Even a one-time use battery would be fine if it cost nothing to manufacture, distribute and recycle/dispose of. One must look at the trade-off in number of recycles vs. cost.

            I replace my one-time AA batteries in my electronics equipment. I do not recommend this, but except for inconvenience, cost, and some angst at environmental costs, it’s not a theoretical problem.

        • Benjamin Nead

          Oh yeah . . . build fancy drive-through robot shacks designed to pop a multi-thousand pound battery in and out of a car in a minute and convince every car company that they all have to design their cars around a specifically-sized battery, just to satisfy the whims of one? What could possibly go wrong with that idea? . . .

          • loebner

            My suggestion was made to overcome a technical problem. There might be a problem of the _will_ with regard to coming up with a standard design. I hate the fact that every time I buy a new digital camera the battery design has changed (even with the same manufacturer (Sony)).

            Congress certainly has the authority under interstate commerce clause to specify a design (best way, authorize NTIS or, say, IEEE to do the design) a battery. Or, the President could have the military require a milspec battery for their EV’s.

            There is nothing particularly difficult in designing an auto with a switch out battery.

          • Benjamin Nead

            Fair enough, loebner. I’m also frustrated by the myriad of battery form factors for my cameras (NB-4L, NB-6L, etc.) But to go as far as insisting upon a cross industry standardization of battery sizes is going to be next to impossible . . . especially as we move beyond older technologies (point-and-shoot pocket cameras, themselves, are rapidly being eclipsed.)

            For instance, just look as tablet computers and smart phones. Each year they become thinner and thinner. We now also see many of those devices sealed so that consumers can’t (unless you want to invest in specialty tools and void warranties) change the batteries on their own.

            Are you going to attempt to get Sanyo and Apple to sit down in the same room and force them to agree on a battery form factor for their portable devices for the next five or ten years? If this is going to be a government-driven edict, then which government do you propose to put in charge to do it? The Chinese? The Americans? By the time you draw up a size specification for, say, tablet batteries, the technology will have already moved on. It’s silly to even worry about this.

            As far as electric cars are concerned, the problems of size standardization is even more daunting. Some traction battery packs are air cooled, some have liquid cooling, Each manufacturer has differing voltage/amperage requirements for associated controllers and motors. The cars themselves come in differing sizes and each manufacturer insists on placing the battery in a different location to accommodate differing passenger and/or cargo hauling requirements, not to mention the size/shape of cells themselves, which are currently being sourced from third party suppliers. We also have yet to see any really standardization on battery chemistry, precisely because that technology is in flux and may never be standardized. Designing a one-size-fits-all box for today’s batteries may be exactly the wrong sort of design 10 years from now with cells we’ll see then.

            Yet, with all that, you are insisting that some paternalistic entity come in to stifle possible innovation for years to come, just so we have one size of EV traction battery with the same bolt-in pattern, plug/connector interface and even the same electrical characteristics? Please step back and take a truly serious look at what you are suggesting and how you are suggesting it be enforced. Sorry, but the idea borders on the ridiculous.

            The very sort of battery technology detailed in the article – solid electrolyte or so-called solid state – will free up engineers to form automotive traction batteries into unusual shapes that will fit between frame members and hug contours of floorpans. We might even find future batteries integrated into body panels and structural members before too long . . .


            So, the prevailing trend in batteries is to move away from a century+ design model of building them into simple boxes and cylinders. This is going to make the implementation of some future EV battery quick swap scenario based on the ill-fated Better Place business model all the more difficult
            . . . especially if you wish to accommodate all competing manufacturers under a single roof and look more than just a couple years into the future.

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