Tesla was recently granted a US patent titled, “Hazard mitigation through gas flow communication between battery packs,” and with the company’s Battery Day event around the corner, anything that may foretell what the revelations will be is seeing some serious consideration. Given that this invention describes a cooling process between a combined metal-air battery pack and non-metal-air battery pack, a first glance suggests that the patent is a Roadrunner-related hint. On this particular patent, though, there’s a bit of background to consider that might not indicate what the application title plus the patent’s publication date implies.
First, U.S. Patent No. 10,763,477 was issued on September 1, 2020, and Tesla’s Battery Day is September 22, 2020; however, the patent’s filing date goes back to January 16, 2017. When it comes to inventions at the US Patent and Trademark Office (USPTO), it’s not uncommon for the legal side of the patent process to take several years to complete, and there are few options available to speed up the process. But even these simple dates don’t tell the whole story on this patent’s timeline.
In addition to being several years in the making, this patent is a continuation of another patent (U.S. Patent No. 9,548,616) which was filed in 2011 with a provisional priority date in 2010. Considering the Model S’s debut took place in June 2012, it would seem that hopes of metal-air batteries getting a Battery Day feature become a bit less bright. Of course, it might be possible that Tesla has been working on the incredible tech that CEO Elon Musk has promised for next week’s event, as he is often full of surprises. Unfortunately, that doesn’t really seem to match either the USPTO’s record of the patent’s history nor the battery-related events that have been reported over the last year for Tesla.
The core of Tesla’s most recently issued patent involves mitigating thermal runaway events that battery packs can be prone to experiencing. By introducing a metal-air battery to the overall lithium-ion vehicle battery system, a cooling method is made possible. As described in the application:
“The present invention provides a system and method for mitigating the effects of a thermal event within a non-metal-air battery pack. In accordance with the invention, the hot gas and material generated during the event is directed through the metal-air cells of a metal-air battery pack, the metal-air cells providing a large thermal mass for absorbing at least a portion of the generated thermal energy before it is released to the ambient environment, thereby lowering the risk to vehicle passengers, bystanders and first responders as well as limiting collateral property damage.”
This same description of the invention’s purpose is also included in its parent patent which has a priority filing date in 2010. While the specific claims (legal descriptions of what’s actually invented) in the recently published patent look to be a bit broader in scope than the older patent, thus indicating Tesla has either continued to develop and improve on the thermal runaway mitigation system or is trying to gain more extensive patent rights, another notable point is in the legal prosecution history at the USPTO.
The patent examiner in the case did not deem the two patents to be unique enough to have different expiration dates, and what’s called a Terminal Disclaimer was required for Tesla to be granted the patent rights. In other words, Tesla’s described battery technology in this particular case hasn’t changed significantly (according to the examiner) since it was first filed back in 2010. It may already be incorporated into the company’s current vehicles in some capacity.
Even without this patent’s promise of metal-ion battery tech as an inclusion in Battery Day revelations, there’s still plenty to look forward to. As some have dubbed the event “Master Plan Part 3,” Tesla is expected to detail its in-house production strategy and give a first look at its company-branded battery cells.
Tesla’s patent could be accessed below.