There are really two stories of varying importance behind the discussion in recent days of "bricking" Tesla Roadster batteries.
The whole brouhaha was instigated by what appears to be a customer that was understandably angry at having to pay $40,000 to replace a battery after parking his car for 6 weeks. When +Tesla Motors opted to open company-owned retail stores instead of franchised dealers http://aol.it/AeyDnI they were determined to handle customer relationships differently from other automakers.
Unfortunately for Max Drucker, it appears that Tesla still has a great deal to learn about dealing with customers and the media. Leaking emails between a customer and the company was totally the wrong thing to do on so many levels.
The more important part of this story however, is the fact that apparently the Roadster battery pack can be permanently disabled by leaving the car unplugged. When it comes to its battery design Tesla has followed a different path from other manufacturers. Tesla is unique in opting to use the same type of small 18650 type cells with metal oxide chemistry found in most laptop computer batteries. These cells have high energy capacity but they also have less thermal stability then the cell chemistry used by companies including Nissan, Ford, General Motors and Fisker. Only BMW, Daimler and later this year Toyota have released cars with this type of battery and those were mainly for test fleets.
Back in 2007, I was told by co-founder Martin Eberhard and former SVP Darryl Siry that in order to maximize the driving range, Tesla would use the full capacity of the cells. This approach leaves open the possibility of complete discharge. Again other automakers leave a buffer of unused capacity at the high and low range. This prevents complete depletion and also protects against overcharging both of which can damage cells.
Using a buffer cuts the potential range but also allows manufacturers to comfortably offer warranties of 8-10 years and 100,000-150,000 miles.
By all appearances, this is a technical issue that is unique to Tesla and perhaps its customers at Daimler and Toyota. It's not clear if the batteries supplied to Daimler for the Smart ED and to Toyota for the upcoming Rav4 EV use the same approach of utilizing the full capacity. The original MINI Es had batteries supplied by AC Propulsion and are now out of service and are being replaced by the ActiveE which uses a different type of battery supplied by SB LiMotive.
At the very least, Roadster owners (and potential customers of the upcoming Model S) need to be very careful with their batteries because this is a real issue for Tesla.
#teslamotors #teslabrick #electriccars #ev #electricvehicles #lithiumion
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Is Tesla 'Bricking' Story Just An Angry Owner's Warranty Claim?
And now perhaps it all becomes clear. The Tesla battery 'bricking' post that was today's electric-car news story and generated reams of coverage may simply be an attempt by an unhappy owner to get Tes…
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Tesla began monitoring the Roadster batteries after model #500, but I agree that this is an oversight. They need to have some kind of fail-safe because if something as simple as leaving a car sitting for weeks can render it useless, there will be plenty of Model S' that die in the future. Tesla needs to fix this now.
Tesla just responded http://www.teslamotors.com/blog/plug-it
"Even in cases of neglect, the latest Tesla batteries are industry leaders. The earliest Roadsters will take over two months to discharge if parked at a 50 percent charge without being plugged in. From that starting point, Tesla has consistently innovated and improved our battery technology. For example, a Model S battery parked with 50 percent charge would approach full discharge only after about 12 months. Model S batteries also have the ability to protect themselves as they approach very low charge levels by going into a “deep sleep” mode that lowers the loss even further. A Model S will not allow its battery to fall below about 5 percent charge. At that point the car can still sit for many months. Of course you can drive a Model S to 0 percent charge, but even in that circumstance, if you plug it in within 30 days, the battery will recover normally."
+Sean Pereira I saw that. https://plus.google.com/114133424228405038490/posts/7i9ff5ZKFjo