Would love to get a conversation going about discharge rate and learning about C. I tend to believe that discharge rate will play a bigger part in battery longevity than some people realize. However, I am definitely no where near educated enough on electrical engineering to even have an intelligent discussion. So, I hope to sit back and listen and interject questions every now and then. So...my first question is: What is 1 C in a PiP? (and am I even using that terminology correctly? haha)
PiP has 4.4 kWh so 1C is 4.4kW. PiP battery is rated 38kW so, that's 8.64 C. Compare that to regular Prius 1.31 kWh NiMH rated 27kW at 20.6 C.
If the charge finishes in 1 hour, it would be 1C. Since it takes 2.5 to 3 hours, it is about 0.3C. It is not that simple as charge rate differs in the beginning than the end.
Volt: 111kW motor / 16kWh battery = 6.94 C Leaf: 80kW / 24kWh = 3.33 C Model S: 310kW / 60kWh = 5.17 C Model S: 310kW / 85kWh = 3.65 C It really depends how the battery was designed. High power pack can do high C but has little energy. Prius Alpha with lithium has 1kWh pack but provides 27kW at 27 C. The opposite end is high energy packs for BEVs capable of low C. PiP has ICE assistance at extreme conditions to maximize life. BEVs have to do everything alone. Volt uses ICE for assist also but at different thresholds.
Will be interesting long term to see how the Volt and PiP batteries handle high C rates. I read on another thread somewhere that it's really not good to be routinely above about 2 C. Any truth to that?
the harder you drive it, the quicker it will wear out. i'm sure toyota has limited the charge and discharge rate to keep users from doing significant damage.
ALL, IF you don't know PLEASE DO NOT comment with nonsense! Markabelle asked a simple question and got nonsense answers! In battery speak 1C is the current that will fully discharge a fully charged battery in one hour! In a PIP that is about 21.25 amps. The OP also wanted a discussion of the impact of discharge current on life. That is a difficult topic in detail, however greater peak discharge currents definitely cause greater thermal stress and probably shorten life. FWIW It appears that Toyota has set a hard limit on discharge current at about 10 C. I personally have observed 210 amps during hard acceleration with a fully charged pack. In addition to discharge current there are other "wear-out" mechanisms, one is a plating mechanism that apparently has a threshold of about 3.7 volts per cell which appears to be why Toyota forgoes about 20% of theoretical capacity by limiting maximum charging voltage and why you should not store the pack in a fully charged condition.
For laptop batteries, probably. Those are high energy cells to get the most electricity stored as light as possible. High power cells like A123 are capable of doing 30C. They provide the most power as light as possible. The amount of energy they hold are less. For PiP, the cells they used are for PHEV application. They have the balance of power and energy.
