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In order of importance: 1: Tesla cells are hard limited to a lower voltage, reportedly 4.1 V rather than the 4.2-4.4 V maximum. Phone batteries run much close
by hwillis 9y ago
In order of importance:
1: Tesla cells are hard limited to a lower voltage, reportedly 4.1 V rather than the 4.2-4.4 V maximum. Phone batteries run much closer to their maximum voltage
2: Tesla cells stay at much lower temperatures and have active cooling. Phone batteries are used to sink heat from the processors and wifi.
3: Teslas have a much lower normal depth of discharge. In addition to the derated voltage, the average American's daily driving distance is ~30 miles or 10-15% of the battery capacity. Phones are often almost totally discharged every day. Tesla's are also typically only charged to 80%, although you can turn that off.
4: Teslas have a low average power use: 300-600 horsepower on tap but cruising on the highway uses very little. In technical terms their current rate is ~.2-.3 C, while phones can have much higher C rates.
5: Phones use an LCO chemistry, Teslas use NCA which is more stable over the long term. Tesla also has custom additive and cathode/anode materials that improve lifespan a great deal.
Phone and laptop batteries almost all come from china, Tesla batteries are korean. They're pretty premium as far as 18650s go so they're used in power tools and really good laptops. However Tesla has their own proprietary chemistry so nobody else gets to use their blend.
- digikata 9y agoA lot of these could be mitigated if phone makers were willing to put in a slightly larger capacity battery and apply more conservative max-min limits in their battery management system. But I guess companies are happy to keep sales up via planned obsolescence.
- photojosh 9y agoMy phone rarely gets below 50%, and I'd say it only gets below 20% a handful of days a year. But yes, I've often thought it would be nice to have a toggle to say "Prolong battery life (as in years)... I only want a 90% charge since I'm not going to be using much tomorrow." I've wondered too whether I should only use a slow (1A) charger for the overnight charge rather than the full 2.4A. But then again, I only keep my phone for 2 years before passing on it, so I've not had to care that much.
- kalleboo 9y agoIt looks like Sony's Android phones have this option https://www.phonearena.com/news/Sony-Xperia-Marshmallow-update-beta-includes-soft-charging-allowing-the-battery-to-live-longer_id82551 https://www.phonearena.com/news/Sony-Xperia-Marshmallow-upda...
- lorenzhs 9y agoI know ThinkPad laptops have this (mine is set to charge up to 90% and only start charging if it's below 80%), and I think I've seen it in some custom kernels for Android ROMs a few years ago, but I'm not aware of any popular devices supporting something like this.
- gambiting 9y agoSony phones have that, I have an Xperia Z5 and you can select an option to "prelong battery life", where the phone only charges it up to 80% and stops(the scale shifts, so 80% shows as 100%, but internally the battery is never at 100%).
- jandrese 9y agoI have a Lenovo laptop with this feature. It only charges the battery up to about 60%, which is fine since that laptop is plugged in a lot. When I am planning to take it out I'll turn off battery safer mode and let it fully charge.
- acchow 9y agoTradeoff between weight, battery life, and battery lifetime. I'm glad phone manufacturers heavily optimize for the first 2 and not the latter.
- ZeroGravitas 9y agoI'm sure that one of the Tesla founders stated that one of the reasons that device batteries failed after a couple of years is because longer life wasn't prioritized by the companies buying them and so not much effort was put into that dimension. You can spin this in a bad way ("planned obsolescence") or a good way (they were optimising for other things that customers valued), but the point remains the same, if car manufacturers (or grid storage units) require longer lifetimes, then it's not a hard physical limit at the current lifetimes that's been hit yet.
- perryh2 9y agoTesla uses batteries from Panasonic (Japanese) [0]. [0] https://electrek.co/2016/11/02/tesla-panasonic-2170-battery-cell-highest-energy-density-cell-world-cheapest-elon-musk/ https://electrek.co/2016/11/02/tesla-panasonic-2170-battery-...
- onetwotree 9y agoThermal regulation is the most important difference, followed by low depth of discharge. There are also some (rather weak) reports that if you take the individual 18650 cells out of a tesla battery they last significantly longer than the NCA 18650s you can actually buy from Panasonic, which indicates that they might made to better manufacturing tolerances or something, but it's really all about Tesla's treating the batteries much better during use.
- evandijk70 9y agoI think this is a good list, but I think reason 3. should be higher up. Rule 3. worded differently: 3. Rule of thumb is that a battery lasts around ~1000 cycles. Phone batteries are discharged fully about once a day, so that leaves a lifetime of almost 3 years. Tesla range is ~ 300 miles, so using this rule of thumb it should last around 300,000 miles. This + reasons 1,2,4 and 5 are why the battery barely degrades over the lifetime of the car.