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.
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.
I'm glad phone manufacturers heavily optimize for the first 2 and not the latter.
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.
[0] https://electrek.co/2016/11/02/tesla-panasonic-2170-battery-...
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.
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.
No, it's not. NiMH have practically no degradation from cycling, which is why Toyota still uses them in the Prius. The tradeoff is in energy density.
Li-Ion batteries are not meant to be held at 100% State of Charge (SoC). There is a non-linear relationship between average SoC over the life of the cell and the rate of degradation. Optimal charge for extended life in a typical 4.2v cell is around 3.9v, or 65% of available stored energy. Keeping an average SoC near 100% can cause up to a 5x loss in battery lifetime. See the link below [0]. Specifically "Table 4: Discharge cycles and capacity as a function of charge voltage limit."
http://batteryuniversity.com/learn/article/how_to_prolong_li... [0]
I mentioned this to a colleague lately who looked at me like a strange animal for having:"worry about cell degradation" even on my list.
Would be cool if there was a similar feature available on phones. Maybe you could rig up something with Tasker or the like on an Android.