Battery Testing

Last night I received a batch of A123 cells and I am starting testing. For those that don't know these are very good batteries that can put out over 20C and have shown very good life cycle in the labs at more reasonable discharge rates.

http://www.a123systems.com/products-cells-prismatic-pouch-cell.htm

The problem is they don't sell to individuals, only OEMs. So the only way to buy them is on the gray market. There is a lot of speculation about how they get on the gray market; some are rejects that don't meet specs (usually slight low capacities) and many have had the tabs cut to make them difficult to use. The other theory is they are not selling as may as they planned so there South Korean factory is selling them out the back door without corporate knowing about it. Finally some are just outright fakes. But all of them have to be bought from China (since people will sell ANYTHING in china without fear of lawsuits). I bought 8 of them from my supplier to make sure they were good before going off and blowing $5k on the ~220 cells for a full pack. If these check out then I will use them to make up my 12V battery.

I am pretty confident these are real A123s that came out the back door given the serial numbers were sharpied out and some of the other markings.

Romulus Anode?

The first check with a DMM and not a good sign on three. The 3 cells with an extra sticker that says "Romulus Anode" have just over 2V. :( I am doing a 2 cycle charge/discharge on one of the cells right now so we will see how it comes out.

FYI, Romulus doesn't refer to StarTrek rather it's Romulus, MI where A123 makes they anodes as opposed to the Chinese supplier they used before. I have been doing more research on the fabrication of these cells and it seems a bit odd. They are all labelled made in the USA but common knowledge holds that they are actually made in South Korea. I find it odd that A123 would fabricate components in the USA then ship to Korea for assembly and them ship them back to USA to assemble into packs. I would think they would manage their supply change better then that.

Test Cell

Here is my test station. A CellPro PowerLab 6 hooked to a PC. It's a bit ad-hoc right now as I can't find my other set of test leads and I have to do some more digging to figure out how to get the PL6 to go to 40amps instead of the 10amps I am limited to now. Even though I have selected a battery power source with 40amp max, the highest it will let me select is 10amps. Speaking of the power source it is a couple of left over 24V batteries from the leadwing project with a trickle charger. I am also using a book plus a battery to provide some compression on the sides of the cell during cycles. This evening I will make some improvements to the set-up.