They use the same 18650 cells that power laptops, yet laptop batteries degrade badly over time. My 1 year old XPS13 reports a battery "wear level" of 29%.
I wonder if Tesla's battery technology could be used in laptops and phones?
Similarly, if you put things like batteries or capacitors in series, you typically want circuitry to balance their voltages, because a pair of 2.7V elements charged to 5.3V could really be at say, 2.75V and 2.55V, which would be unhealthy for the former cell. I think those imbalances are also caused by small differences in the individual elements' properties (capacitors are typically less precisely-tuned than resistors) which will drift further over time with wear and temperature changes and overvoltage conditions and whatnot. So that 2.75V cell would degrade very rapidly compared to the 2.55V one, probably causing even larger imbalances until it eventually fails.
Most lithium cells have basic protection circuits built-in against over/under voltage and overcurrent (e.g. shorts,) because they tend to explode if you leave those things out, but they definitely last longer if you pay attention to them as individual cells rather than a system.
Sure, if you want a laptop which you can only recharge once per week.
Laptops and phones go through charge cycles much faster than cars; I'm sure Tesla has tuned their designs to maximize performance in that usage environment.
What is also an advantage: Teslas can cool (and I believe also heat) the batteries so they don't enter temperature ranges where degradation is accelerated. In a laptop and certainly a phone there is neither space nor weight available for a thermal management.
Laptop and phone batteries are physically close to heat sources + are used frequently to substantial degrees of discharge + frequency of charge cycles after substantial discharge.