battery technology

[adric22]

This goes for more than just the Tesla, but EVs and hybrids in general. We saw GM build a very viable electric car back in the 1990's using standard lead-acid SLA batteries. Then we saw them improve upon that using Ni-Mh batteries. I know GM tried to blame battery technology as the failure of their EV program, but we all know that wasn't true. And now they try to say the only reason the Volt is viable today is due to the better batteries available.

I still don't buy it. Lithium batteries are very expensive and I certainly believe a cheaper electric car could be built based on traditional, proven, battery technologies.

And I just had an interesting thought. One of the biggest concerns with lead batteries is the fact that they tend to wear out over a few years and need replacement. Well, I started thinking about that and the only thing that wears out is usually the plates inside. So I started thinking how it might be made cheaper to maintain an EV based on lead batteries. What if the manufacturer actually designed their own battery? And the battery could have some kind of removable top which is bolted down and has a rubber seal. When the battery wears out, you could take your car down to the dealer and they could just remove the lead plates, put them in a pile to be recycled, and lower new plates into the battery and bolt it back closed.

[prius2go]

Why not make the bottom of the car from plastic in the shape of a bath, fill it with acid and drop in the replaceable plates from the top.
As theres so much batery in an EV why not make it part of the structure?

[daniel]

The advantage of lithium is its better weight to energy ratio. And even though lithium is more expensive, some EV enthusiasts believe that its longer life translates into lower lifetime costs.

Makers of lead batteries are not resting on their laurels. They are constantly improving on batteries in terms of energy to weight ratio, power delivery, lifetime, etc. At this point, no simple suggestion like removable tops is going to change the situation.

A big dichotomy is between sealed lead batteries, and floodies. Sealed are easier. There's no maintenance. But if they do lose electrolyte they're toast. That's not supposed to happen. But it does. Floodies are more durable because you can add water. The disadvantage is that you have to add water. And they give off hydrogen gas during charging. And they can spill acid. There are many different kinds of sealed batteries; every sort of scheme you can imaging for addressing the issues.

But in the end, I decided that sealed are too fragile and flooded are too hazardous and both are too heavy, and I went to lithium. More expensive, but a lot lighter and more durable and should last longer. I've got lithium-iron-phosphate (LiFePO4) in both the Xebra and the Porsche.

Batteries are definitely the sticking point for EVs.

[Flying White Dutchman]

any video and or pics on your "I've got lithium-iron-phosphate (LiFePO4) in both the Xebra and the Porsche"

[Matt Herring]

Or we could progress to this...

YouTube - yokohama battery switch

YouTube - yokohama battery switch

[daniel]

Originally Posted by Flying White Dutchman

any video and or pics on your "I've got lithium-iron-phosphate (LiFePO4) in both the Xebra and the Porsche"

Here's a picture Paul sent me when he was building the car. It shows the front bank of batteries before he installed the cover over them. To get at the Xebra's batteries I have to remove a cover or lift the back seat, either of which is hard to do.

Originally Posted by Matt Herring

Or we could progress to this...

That video has already been posted, and discussed at length, in the Better Place thread.