h a l f b a k e r yFlaky rehab
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
login
|
|
|
The proposal is for a new way to use and provision electric car batteries. Current usage is a variety of over-provisioning and fiddling with limits. Those can still be done, but this idea will reduce the cost of replacing batteries. Split the car's battery pack into three packs. Always use them in the
same order. So drain number 1 first, then number 2, then number 3. As most usage and charging is for short trips, number 1 will wear out faster and can be replaced separately three or four times before number 2 needs to be replaced, at a third the price of a full-sized pack. At the same time the full capacity is available, and if replacement isn't done, there's no more overall wear than using the traditional one pack. Bonus: you can place pack 1 in the easiest-to-reach location.
|
| |
Wow, that sounds a lot better than taking 3 minutes to change your battery every 4 years. |
|
| |
Given typical capacities and lifetimes, under this scheme number 1 needs to be replaced every third year, number 2 halfway though the life of the vehicle, and number 3 never. |
|
| |
Just kidding, it's actually got promise. |
|
| |
Fast charging/discharging degrades a battery quicker, so it's better to draw/add power across all packs to spread the load, so to speak. |
|
| |
Individual cells degrade differently, and you can have a pack serviced to replace the worst cells to improve the overall pack's maximum charge. So, in your example of having 3 seperate packs, it would help just to shuffle the individual cells between packs based on their performance after a few years. |
|
| |
After further thought, I believe your idea has merit as a selectable mode. You could program the car to draw low power from only 1 pack up to a limit, then involve the second pack to another limit, and the third only for hard acceleration. Gentle regenerative braking could also be routed to only 1 pack. This would also mean slowing the rate of charge when fewer packs are being charged after some are full. |
|
| |