3 ms·
No, it's incorrect, physics does not mandate that battery should heat up as you expend energy. Ideally all the energy would go into kinetic energy and be dissip
by ajnin 9y ago
No, it's incorrect, physics does not mandate that battery should heat up as you expend energy. Ideally all the energy would go into kinetic energy and be dissipated by friction losses due to air or contact between the road and the tires. The battery heats up only because the process of tranferring the chemical energy from the batteries to the car motion is imperfect, and there are internal losses do to the internal resistance of the battery.
I'm not saying that Tesla has invented a sufficiently efficient battery, but to vaguely claim "physics" makes it impossible is wrong.
- 0xbear 9y agoIt does. It will heat up. To quote a physics textbook: “Power transfer between a voltage source and an external load is at its most efficient when the resistance of the load matches the internal resistance of the voltage source.” IOW in the configuration where the power transfer is at its most efficient, battery has to dissipate as much thermal energy as motor(s) are consuming. Too much internal resistance and most of the thermal energy ends up in the battery. Too little, and your motors aren’t going to do their best. But in either case even with the load that’s not 100% matched, you do end up with a ton of heat dissipation in the battery when a heavy car like this is driven hard.
- carry_bit 9y agoThat sentence from the textbook is poorly worded, see https://en.wikipedia.org/wiki/Maximum_power_transfer_theorem#Maximizing_power_transfer_versus_power_efficiency https://en.wikipedia.org/wiki/Maximum_power_transfer_theorem... Yes, power is lower when efficiency is greater all other things equal, but you work around that by not making all other things equal.