Automotive

Tiny computers could keep EV batteries from crapping out when one cell dies

Tiny computers could keep EV b...
One of the microcontrollers, which allows individual battery cells to communicate with one another
One of the microcontrollers, which allows individual battery cells to communicate with one another
View 1 Image
One of the microcontrollers, which allows individual battery cells to communicate with one another
1/1
One of the microcontrollers, which allows individual battery cells to communicate with one another

Perhaps along with the fact that they don't allow for thousands of miles of travel on a single charge, electric vehicle batteries do have a shortcoming – they're only as good as their weakest cell. That's because all their 100-plus cells are connected in series, meaning that if one of them dies, then the whole battery pack stops working. That could be about to change, however, thanks to research being carried out at Germany's Fraunhofer Institute for Manufacturing Engineering and Automation.

In a prototype system developed by Fraunhofer, each cell within a battery has its own microcontroller that monitors parameters such as temperature and charge level. All of these processors communicate both with one another, and with the vehicle's central onboard computer.

In this way, if an individual cell loses power while the others are still well-charged, it's simply shut off and "uncoupled" so that the current bypasses it. This means that the vehicle can keep going, using the electricity stored in the other cells – ordinarily, this wouldn't be possible.

Drivers are still made aware of the faulty cell, however, so they can have it (and only it) replaced at their convenience. By contrast, if it were a conventional battery pack, the whole thing would have to be replaced.

Not only should the technology make EV batteries more dependable and longer lasting, but it could also lower their price. This is because cells of slightly varying capacities could be used, with no one cell throwing off the capacity of the battery pack as a whole. Ordinarily, cells of exactly the same capacity must be selected, which drives up production costs.

The company is currently working at miniaturizing the technology.

Source: Fraunhofer

5 comments
swaan
Teslas have around 8000 cells and they are not all wired in series. Further more, a single failed cell results in performance degradation, not total failure. Looking at the PCB - it looks quite expensive and batteries are already expensive = I don't see it happening in mass-produced vehicles for general use.
Tom Lee Mullins
I think this would make battery powered vehicles more appealing since one replaces only the defective battery instead of all of them.
dhz
On cell monitoring of every cell has been on the ZEV Electric motorcycle and scooter battery since 2009. http://www.zelectricvehicle.com/resources/LRCBatInChasWeb.jpg If a cell should go bad, the BMS system can tell you which cell to pluck out and replace. The reality of the current state of the art, at least as far as the ZEV Electric motorcycle experience has been, is that the best battery from the quality producers are so good, that not one cell has failed in any lithium motorcycle since 2010. Considering that motorcycles allow the battery to be pulled down quite low where cars hold back 30-40% of the battery capacity to get longer life, the reliability of the current generation of cells is extremely good. Zero failure is hard to beat.
pmshah
I am guessing one would you need 1 such circuit per cell. Could turn out to be a pretty expensive proposition.
Gizzyfuel
It might be en extra hundred buck at best since if I am wrong it will have just a basic cell electric (insert what ever name is use) tester and if it fails to pass to charge it it will flip a switch to allowing it to bypass. And I do hope they just dumb down the circuit so that it wont draw too much electric charge from the cell but rather just be a simple infinite test loop pass.