A First Look At Toyota’s Improved Solid State Battery Patent

Toyota solid state battery patent



It’s no secret that Toyota is working on a number of advanced, solid-state battery technologies for future electric vehicles. The company has been talking about in public for years, in fact. Once, it was maybe supposed to come out in 2020 (that was the target a long, long time ago), and that still might be the cast. Whatever happens, there’s paperwork to file before we get there.

Which brings us to U.S. patent application #20170179545. The filing drawing (above) might look like a simple, boring sandwich, but as you might guess, it relates to Toyota’s work on a solid state battery. The advance that is under application describes how Toyota has improved the battery’s thermal stability through the addition of a “specific phosphate ester” that did not degrade performance. This is obviously a good thing for solid state technology, especially as it compares to today’s li-ion cells. This is how Toyota describes the benefit:

With regard to the lithium batteries that are currently available in the market, since liquid electrolytes including flammable organic solvents are used, installation of safety devices that suppress temperature increase at the time of short circuits, and structures for preventing short circuits are needed. Meanwhile, since lithium batteries that have been produced into all solid state batteries by converting the liquid electrolyte to a solid electrolyte layer do not use flammable organic solvents in the batteries, it is contemplated that simplification of safety devices can be promoted, and the lithium batteries are excellent in view of the production cost and productivity.

A number of different chemistry options are described in the application (34, in fact), but I leave it to people with science degrees to tell us what it all might mean. Beyond solid state batteries, Toyota is also working on lithium-air batteries, so anyone who thinks that this whole EV game is just about played out should take a look at some patent filings now and again.

Source: USPTO

Categories: Battery Tech, Toyota

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19 Comments on "A First Look At Toyota’s Improved Solid State Battery Patent"

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Tesla battery guru claims his group’s advanced battery testing has led to discovery of a “secret sauce” that now doubles the life of the cells in their cars (from 10 to 20 years).

I expect (sometime soon) OEM competitors might ‘reveal’ that much better batteries are just around the corner in the hopes of slowing down Tesla sales and loss of market share.

As good as battery lab testing may be, it is not a complete substitute for real world conditions and real time.

Lou Grinzo

How the Other Car Companies (OCC) respond to Tesla, and in particular the likely success of the M3, is as fascinating as it is important. In the short run I’m sure we’ll see exactly what you suggest, with the OCC playing PR games to try to slow the Tesla juggernaut.

But for me the really interesting detail will be: If the M3 sells anywhere near as well as we’re hoping, then we’ll find out pretty soon which of the OCC have been doing a lot of BEV development behind the scenes. For example, if late this year Honda announces a 200+ mile version of the Clarity that will ship in the US by end of 1Q2018, we can safely assume that they’ve been working on it for some time.

Maybe I’m hopelessly optimistic, but I simply can’t believe that nearly all of the OCC are being as stupid as they appear regarding BEVs. If they have even the slightest awareness of technological and market trends (a stretch for some of the OCC, I admit), they’re working furiously on products they can launch relatively quickly once batteries are cheap enough and consumer psychology shifts enough.


Bill Ford’s a little nervous ….


It would have been nice if Ford had even mentioned EVs when the discussion briefly turned to Tesla. Instead, Ford pivoted to autonomous driving, never once addressing the large, electric elephant.


All the autonomous ride share will (or will soon) be pure EV’s.

— that’s been my opinion for a while, and I recently saw GM’s vp of propulsion predict the same.


I agree… The OCC have reasons to be silent about anything they’re doing internally. Tesla has to beat their chest to get noticed. Even at 500k vehicles Tesla would still be 1/20th of GM’s annual sales. The fact we didn’t know the Bolt existed until it was announced you have to imagine it isn’t the only EV they’re working on.

There is nothing special about EV’s and the technology is well known. It really comes down to the availability of batteries in whatever form.


Maintaining momentum is a favorite thing for entrenched companies. Speak with Blockbuster, Kodak, and others who labeled technology as not applicable to them.

philip d

I believe the longer lasting cells were for their stationary storage cells which uses NMC chemistry in their cells. The cells for their cars use NCA chemistry.

They said they were working on implementing this new breakthrough with the NCA chemistry though but haven’t solved it yet.


I stand corrected. I should not have said *in their cars*. Although he (Dahn) does say there’s no reason why both the cars and the batteries couldn’t last 20 years..

Too bad the video has been made private.



Honestly, people need to stop blowing Tesla out of proportion. It’s not a Juggernaut, it’s more of a minow. For all the vaunted 400,000 Model 3 preorders, Honda sells 300,000 plus Civics each and every year and that’s just ONE of their cars.

The other car companies are not concerned with Tesla at all. Best case scenario, Tesla gains a solid foothold and joins the pack. They’re never going to claim all the sales of the car industry, or even half.

The bigger risk for automotive companies is if they fall behind on R&D and bungle the electric drive transition. Not because they’ll lose sales to Tesla but because they’ll lose sales across the board to all manufacturers that have their act together.


That is a more realistic assessment. Tesla has done a great job buying an old Toyota factory and making an aluminum electric car. They should be congratulated, but if they take too many risks it could stall.


VW have been working on SS batteries for quite some time and seem pretty confident that they will be ready around 2020, no doubt sitting on them until their hand is forced wouldn’t exactly be a surprise either.


I’m working on an air-air battery. Just haven’t gotten to the storage phase, but it looks promising. Very low mass. Should have VW beat, in 2021.


I’ve owned Toyotas over 30 years and they are great ICE cars (I still have an early Prius). So I’m hoping Toyota really does have a viable BEV waiting in the wings around 2022 when I retire that Prius. If not I’ll just have to go to an M3 ?


Patents are nearly meaningless. We allow patents on useless, obvious and vague technologies. For all the outcry it just keeps on getting worse.

Solid state batteries may or may not be successful, but it is a waste of time to plow though patents for evidence.


Gee, whiz, genius…you’ve got the whole world outsmarted, eh? Do tell about the worthlessness of the patent system!


There are many experts who believe patents are detrimental to innovation.


It would appear to be a double sided battery? Two cathodes (?) on the outside and a single anode (?) in the center? Or vice versa.


After a quick diagonal read I understand the following.

The Phosphate ester is said to be there to act as an organic radical liberator to react with free oxygen radicals in the case of a temperature rise. The oxygen reaction with the organic radical is giving less heat than if the oxygen reacts with sulfur like it otherwise would. The lower energy release tends to prevent thermal runaway.