Hi John et al.,,,, I'm still stuck in Las Vegas due to weather, but now without a car and in an airport hotel.... argggg! ... and have a poor internet connection... but wanted to restate some information regarding the so-called 'gen 1,2,3' technologies, as clarified for us at the meeting.
Gen 1 and 2 both use manganese dioxide, and as far as we know, so does the gen 3. It was clearly stated that the phosphate materials are not what is being called 'gen 3'.
It was then loosely stated that gen1 'are the old specs,' and gen 2 and 3 are each roughly 20% better than the previous. This can be corroborated for gen 1 and 2 based on the spec sheets we were given at the meeting, which were a year old (dated 2/99) and identical to what we saw last year. If you simply take the (current x voltage / weight), you can verify the following for yourself:
The specs provided for the two large format cells are both gen 1 specs. These include the original 4"x4" (model 44O) cells, which were the ones sold to Alliant up until now; and the 140x70mm (model 74A) cells. The specs are 121 and 125 wh/kg, respectively.
The specs provided for the two cellphone cells are the gen 2 specs. The standard startac cell (model 65M, the 1000 mAh cell) shows 141 wh/kg, and the model 43E cell (890 mAh cell) shows 144 wh/kg.
Notice the subtle differences in specs even between the two large format cells, or the different cellphone cells (even between cells of the same cross-section but different thickness, such as model 43D vs 43E). This is due to the different amounts of packaging material for the given volume of cell within.
I would recall to you the comment at the meeting that the most efficient package would thus be a square shape, since the relative weight of the packaging 'edging' would be less for that than for a long and thin cell such as used in the globalstar phone (OT: an interesting observation about that shape would be that it seemed the phone may have originally been designed for two larger li-ion cans put end-to-end, and then Qualcomm chose to use li-poly cells instead).
Anyway, Lev stated (as he had in the past) that they would soon no longer make any cells using the gen1 materials. I would expect the large-format cells with the gen2 materials to come out to at least 145 wh/kg, given the more efficient packaging. THIS is your '20 % improvement over gen 1'. (ie, do not directly compare the gen2 cellphone numbers to the gen1 laptop cell numbers.)
OKAY, we also now anticipate a 'gen3' product sometime within the year, which is 20-30% better yet again than the gen2 specs. For the large-format cells, this would result in a laptop cell providing 174 to 185+ wh/kg (let us assume the more conservative 174 wh/kg baseline for now).
As a reference, the best li-ion (liquid electrolyte) cells, packaged in aluminum cannisters, max out at 136 wh/kg, for a prismatic cell over 6.5mm thick. We've got those beat.
Also as a reference, Sanyo posted specs for their 'gel li-ion' cells (not a true lithium-polymer cell) that was 156 wh/kg. However, these cannot be made larger than a postage stamp, and reports are that the recharge characteristics are poor (low number of recharge cycles), the cells behave poorly at low temperatures (there is a NRI research report describing this), and it is known that these cells involve manual manufacture for some critical stages that could lead to very inconsistent yields and performance. So, numbers ain't everything.
All in all, the level of quality control exhibited by the Valence approach to manufacturing lends support to their claim that no one's cells touches theirs, all things considered.
This is going to be a very interesting and fun year, as we watch the products roll out!
Regards, Rich
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