Tesla Files A New Patent, Which Aims To Make Batteries Safer



When it comes to the risk of fire, all indications are that electric vehicles are safer than fossil burners. However, batteries can and do catch fire (as Motor Authority once quipped, there’s no way to store large amounts of energy without a risk of fire and explosion, except perhaps “distilled unicorn tears”), and when they do, the media makes sure that video of spectacular fireballs are quickly broadcast around the world.

*This article comes to us courtesy of EVANNEX (which also makes aftermarket Tesla accessories). Authored by Charles Morris. The opinions expressed in these articles are not necessarily our own at InsideEVs.

Source: Tesla

Making batteries safer is an important priority, and Tesla recently filed a patent on a new technology aimed at doing just that. The system is designed to isolate damage caused by failed battery cells, and prevent them from affecting intact cells in the pack.

Source: Charged

When battery cells fail, they typically release hot gases that can spread the damage to nearby cells. Tesla’s patent describes the use of two interconnects that would be positioned over multiple battery cells, as well as a top plate with weak areas designed to rupture when failed battery cells release heat and create pressure.

Source: Charged

“The system may include features or material to thermally insulate the battery cells from the heat generated by other cells…such as a polymer-based insulating material or another type of insulating material,” reads the patent in part. “The system may also include features, such as a cold plate or heat pipes, to remove heat generated by the battery cells…The features or material to perform this electrical insulation may include the interstitial material or a sleeve…In alternate embodiments, an air gap may provide the necessary electrical isolation. The energy storage system may [also] include features or material for directing the hot-gas discharge during failure of a battery cell.”


Written by: Charles Morris; This article was originally published in Charged. Source: Teslarati

*Editor’s Note: EVANNEX, which also sells aftermarket gear for Teslas, has kindly allowed us to share some of its content with our readers, free of charge. Our thanks go out to EVANNEX. Check out the site here.

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6 Comments on "Tesla Files A New Patent, Which Aims To Make Batteries Safer"

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The patent is quite interesting. It describes some variants that seem to be exactly what is used in the Model 3 battery, as well as some other variants. (Possibly used in Powerpack 2 / Powerwall 2? Or maybe some future products?)

Among other things, it explains the purpose of the much-discussed “blue goo” in the Model 3 battery: it’s for electrical isolation; thermal isolation; and for directing the flow of hot gasses (aka flames) when individual cells catch on fire, to prevent it from spreading to other cells. (Instead directing it to weak areas in the top cover.)

So it’s a safety feature, as I suspected, and probably what enables the much larger modules in the Model 3 battery pack compared to Model S/X. If this mechanism works well, it might in fact be safer than the previous smaller modules without it — which would be one more reason for Tesla to switch the older models to the newer architecture too as soon as possible…

“…and for directing the flow of hot gasses (aka flames) when individual cells catch on fire, to prevent it from spreading to other cells.”

Interesting, thanks!

I remember reading comments indicating one of the functions of the “goo” was to prevent hot electrolyte from an exploding cell from splashing onto nearby cells, retarding or preventing a thermal runaway cascade event. So this patent says it’s to direct the flow of hot gasses, instead.

Maybe those previous comments were just speculation? Or maybe the goo serves other functions not described in the patent. It certainly seems reasonable to suggest the goo would form a barrier (perhaps just a partial barrier) preventing hot electrolyte from coming into contact with other, undamaged cells… whether that was the intent of Tesla engineers or not.

As long as the electrolyte is not hot enough to decompose and turn into hot gases, it’s not hot enough to ignite other cells… So the idea that “splashing electrolyte” is a problem seems strange to me.

Forced Volt->Bolt Conversion

A few months ago I happened to run into a bunch of papers on this topic, at history.nasa.gov. A bunch of research has been done on cell isolation using 18650 cells as a sort of standard model. Some of the methods mentioned in the application seem familiar from that collection but undoubtedly Tesla is familiar with this work.

Every application must contain mention of prior art.

I say, why would someone not want to patent safety feauture, never the less people should pay first…