On 25 Sep 2002 at 22:12, Evan Tuer wrote:
> Hrmmph.. Let's race some datasheets (with a view to the <20K concept
> car)
>
> NiZn MB100-12
> Price $465 in 1001 qty
> Weight 20.5 Kg
> 80Ah * 12V = 960Wh
> energy density 46Wh/Kg or 82Wh/Litre
> Price per kWh: $484
> Cycle life: ???
>
> LiIon TS-LP42V
> Price $1300 in 1001 qty
> Weight 35Kg
> 100Ah * 42V = 4200Wh
> energy density 120Wh/Kg or 154Wh/Litre
> price per kWh: $309
> Cycle life: 500@80%DOD
>
> Someone want to chip in with NiCad, or correct my figures so far?
>
Okay, but you may be surprised:
Saft STM5-100MR
120ah to 1000 cycles, 6v nomimal = 720 Wh
Mass 12.9kg
specific energy 56 Wh/kg
specific power (peak) 500 W/kg
Price $347 each*
Price per kwh = $482
Cycle life
1000 cycles at 120ah
2000 cycles at 100ah
3200 cycles at 80ah
Please correct my math if I've made an error here.
With the price per kWh comparable to NiZn and the cycle life likely to be
much longer, the only advantage I can see for NiZn over NiCd is that it's a
sealed battery. Nicads' durability is apt to be much greater, as Jerry
Dycus has pointed out.
When you factor in cycle life and look at cost per (theoretical) delivered
kWh, nicads come out even better, 21% to 60% lower per kWh:
NiZn MB100-12 (taking cycle life as 800, a guess): $0.61 / kWh
LiIon TS-LP42V (cycle life 500) $0.62 / kWh
Nicad STM5-100MR
(cycle life 1000, 120ah): $0.48 / kWh
(cycle life 2000, 100ah): $0.29 / kWh
(cycle life 3000, 80ah): $0.24 / kWh
While some say that NiZn has an environmental advantage over nicad, IMO
producing them in China (which has an abominable record for environmental
enforcement) negates much of that advantage.
* Saft price is for small quantities, per Lesley Walker -- thanks Lesley.
This price has actually dropped since the last time I checked and is now
lower than it was when I first inquired in 1999. It would undoubtedly be
even lower in 1000-lot quantities, though I don't know how much lower.
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David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea rider 36vdc
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