Det är väll en ganska stor skillnad mellan 500 cyklar och 5000 cyklar. Hybridbilar som Prius och Volt klarar många cyklar men de använder bara en liten del av batteriets kapacitet vilket gör att livslängden ökar markant, men naturligtvis blir då batteripaketets användbara kapacitet också mycket mindre.
Om många av Teslas bilar skulle få batteriproblem inom garantitiden vet jag inte om bolaget klarar detta. Så helt riskfritt är det nog inte trots 8 års garanti, Mazda ger f.ö. 10 års nybilsgaranti och Mitsubitsi 8 år, så unik lång är inte Teslas garanti.
Risken är väll just som du skriver att de flesta då kanske väljer att inte byta batteriet när det har blivit dåligt efter att garantin gått ut och att bilen skrotas. Det skulle göra elbilar mindre brå ur miljö-, och ekonomisk synpunkt om deras livstid i praktiken blir ca hälften så lång som vanliga bilar. Det borde även påverka värdeminskningen / ägandekostnader om man i princip ska skriva av den helt på 8-10 år, trots att elbilars övriga komponenter borde hålla minst lika bra som vanliga bilar, som nu i snitt skrotas efter 20 år.
Här är en artikel som inne på samma problematik
http://www.energyharvestingjournal.com/ ... 005281.asp som menar att superkondesatorer vore ett bättre alternativ som energilager för elbilar
Citat:
Troublesome life of rechargeable batteries
Electrification of public transport reflects concern about causing local noise and air pollution and seeking a green image. Indeed, these are now very strong drivers of the purchase of hybrid and pure electric aircraft, boats, industrial and commercial vehicles, whether they use lithium-ion batteries or supercapacitors or both. Nonetheless, let us pause a moment on that statement. The supercapacitors last for the life of the vehicle but the lithium-ion batteries do not. The cost of replacing the lithium-ion batteries is so huge, at over $10,000 even in a pure electric car, that it is likely that the vehicle will often be destroyed after the four to eight year life of that battery and a new vehicle will be bought prematurely rather than the old vehicle be fitted with a very expensive new battery. It is the opposite of green. Increasingly, such a situation, triggered by the short life of expensive lithium-ion batteries, will be questioned by industrial and commercial vehicle operators. Indeed, Renault pointed out at the EVVC meeting in Brussels this week that the poor resale value of pure electric cars and lack of any official resale price is inhibiting growth in sales. That is closely related to the lithium-ion battery problem.
Lithium-ion batteries have been replaced by supercapacitors in power tools in space stations and some on earth because the frequent but much faster charging needed is tolerable in the interests of reliability and life. The same happened with the new Toyota Formula One hybrid racing car because of reliability and performance.
So where are we now?
Supercapacitors are taking a tiny market share from lithium-ion ion batteries, partly by being placed across them so less battery is needed and that battery lasts longer as in the Bolloré Bluecar, the Mazda pure electric sports car and many pure electric buses in China. Dismissed as insignificant by lithium-ion battery manufacturers, that trend is accelerating and we actually have a disruptive technology here. The reasons for using large supercapacitors and their variants continue to be mainly reliability, performance and life but nowadays cost-over-life is increasingly cited as the primary source of payback.
What next?
The important sea change in 2013 is designers increasingly noticing that supercapacitors are safer than large lithium-ion batteries with a smaller percentage of fires and toxicity and failures to work in life-threatening situations and the gap is widening. Attention is turning to alternatives. There are many reasons for this. As a US Senate committee put it, a rechargeable battery is like a living thing with very complex, poorly understood chemistry, considerable unpredictability and swelling and shrinking during use can assist in self-destruction. Often it cannot be fully discharged for safety in a vehicle accident or for safe shipment for example and life is relatively unpredictable. By contrast, supercapacitors are electrostatic devices that do not change shape during use. While it is wide of the mark to say they last forever, because anything containing a liquid has a finite life, it is true that supercapacitors are often guaranteed for up to ten years and they typically last for twenty years or more. They can be fully discharged for safety and they are more easily made to consistent quality standards.
Supercapacitors continue to be improved faster than lithium-ion batteries where toxic flammable electrolytes largely remain and are the fuel of the fires. By contrast, IDTechEx Research analysis shows that toxic, flammable acetonitrile was in the past used by almost all supercapacitor manufacturers but now only 51% use it exclusively, a figure dropping every year.Non-flammable aqueous electrolytes are used by most of the new entrants, so we shall soon have most suppliers offering non-flammable supercapacitor electrolyte. Lithium-ion battery proponents can only look on in envy at this.