China 'vs' Japan, South Korea Lithium Cells

[Ron Adamowicz]

I will show the difference between Chinese "knock-off" cells compared to true cells built in vacuum chambers in Japan and South Korea. First, almost all cells in China are assembled by hand or small hand operated machines, all cells in Japan and South Korea are assembled via automation in vacuum chambers. Let me clarify one point, there are some Japanese, and South Korean companies building cells in China, these new plants use vacuum chambers with automation, but mostly all Chinese owned companies assemble their cells by hand with tons of contamination.

Note: For now, I am leaving out European cells like Saft, etc. They are very expensive.

 

[Ron Adamowicz]

Good article:

"test results did reveal that cells from China that were tested had the performance that decreased most rapidly. Cells from Japan and Germany did the best, while ones from South Korea and the US were in the middle of the performance range."

http://cleantechnica.com/2015/03/27/battery-storage-test-shows-lithium-ion-cells-last-5x-longer/

 

[Ron Adamowicz]

Another example:

I built two of the world's fastest EV drag cars, Warp Factor II & Warp Factor III, I was sponsored by a Chinese company that produced all types of lithium cells. I sent my Chinese sponsor the specifications I needed to build a 425 volt pack that dished out 5000 amps. The cells I requested were lithium polymer because they produced the highest C-Rating. After receiving my cells, I had to QC test every cell, the fail rate was above 4%, not good. My BMS had to work overtime to keep the cells regulated. I had to rebuild the pack 4 times over a two year span to replace dead cells.

 

[George S.]

The downward price pressure on lithium cells has been pretty tremendous. If you look on the Luna site, they offer Korean cells for around $4 each. Even a 'big' battery pack is generally 50 cells, so do the math. It's not a huge deal and a cost of $2 a cell doesn't save much.

The LiPos end up in quad-copters where they serve the need for high amps, obviously. Hobby King sells a lot of LiPos and I haven't read of too many problems, but there are some. For ebikes, lithium cells are winning out. Not sure how the Chinese LiFePo batteries stack up. They are cheap, and many people have used the packs in ebikes. But now the weight is killing them, and the cost advantage has shrunk.

Great info.

 

[dugal]

Is it true that Lithium batteries develop a "memory" and the first thing you should do after fully charging the batteries is completely discharge the battery and then fully charge it again? As I understand it this conditions the battery "memory" to allow it to be re-charged at 100% of capacity. If not done this way, the battery never reaches a full 100%.