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Technology Stocks : VALENCE TECHNOLOGY (VLNC) -- Ignore unavailable to you. Want to Upgrade?

To: Dennis V. who wrote (7274)	1/21/1999 11:02:00 AM
From: Pronichev	Respond to of 27311

GVANDER: What do you think of the specs just posted by Dennis V.? (post # 7274) (thanks Dennis for the post) Michael PS LITH has a real nonsense press release out today.

To: Dennis V. who wrote (7274)	1/21/1999 11:23:00 AM
From: P. Ramamoorthy	Read Replies (1) \| Respond to of 27311

Dennis - Re.:"...capacitance of 500 milliamperes and ..." What they mean by "capacitance"? Is it capacity (mAh)? Ram

To: Dennis V. who wrote (7274)	1/21/1999 12:54:00 PM
From: kolo55	Read Replies (2) \| Respond to of 27311

Thanks for the specs on the Matsushita battery. This another small footprint cellphone battery with a capacity of about 1.9 Wh. I find it interesting that all the players who have announced production capability lately are pushing cellphone batteries of 2 Wh or less. We don't seem to be seeing any specs or production announcements for notebook computer batteries in the 30-40 Wh range. I wonder if there are technical problems making the larger size cells. Let me propose a hypothesis: Perhaps the yield falls off dramatically as the cell area increases. In the semiconductor area, they sometimes use a metric called 'defect density'. If the Li-poly yield correlates to defect density, then increasing the cell area increases the chance that a 'killer defect' will occur somewhere on the cell. So for larger area cells, the yield will fall off dramatically. For example, lets say a manufacturer is getting a yield of 50% on cellphone cells sized 3.5 cm by 6.2 cm (Matsushita size). Using a conservative simplifying assumption, that there is only one killer defect on the bad cells, then the defect density is 2.3 defects per 100 sq cm. The 4x4 Valence laptop cell is about 100 sq cm, so this manufacturer would expect to see an average of 2.3 killer defects per Valence sized laptop cell. If the defects are randomly scattered, then the yield would only be about 14% on the laptop cells. On a 8x10 cell size rumored for some notebook suppliers, the yield drops off further yet. We know that Valence had troubles with laminate quality leading to poor yields on laptop cells. We have no reason to believe that other manufacturers haven't encountered the same problem. The fact that no other manufacturer has announced startup of a large cell line is interesting, if my hypothesis holds true. I'm not the best person to comment on the correlation between yield and cell area. Would anyone else care to comment? Paul