EV Fundamentals: What Damages a Battery?
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What Damages a Battery?
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| 00:00 | There's a lot of misinformation out there about how long lithium batteries will last, and to be fair, that's not really all that surprising. |
| 00:07 | You only have to look at the rapid decline of your typical smartphone battery over a couple years of use to jump to conclusions about electric vehicle longevity. |
| 00:15 | But critically, unlike your cell phone that has very little battery thermal management or focus on battery longevity, EVs are designed to take care of their batteries as a first priority. |
| 00:24 | Modern EVs wake themselves up to condition the battery if exceptionally hot or cold, and manufacturers recommend against leaving a battery fully charged for an extended period of time, and that's for good reason. |
| 00:34 | Studies into lithium battery damage have demonstrated that the main factors that wear out the batteries are related to excessive time at high temperatures while at a high state of charge, as well as aggressive charging and discharging when the battery is cold. |
| 00:46 | Total charge cycles from 100% to 0% will wear the battery much faster than cycling it between 90% to 10%, so most EVs include a hidden buffer to keep within those limits. |
| 00:57 | Although some manufacturers will allow the customer to have nearly full access to the energy of the battery, and instead use education and notifications in the car to guide users towards not using the full range of the battery unless absolutely necessary. |
| 01:10 | Currently, the common consensus for the least amount of battery degradation for NMC cells is achieved by keeping them under around 3.9V per cell, and for storage, keeping the cells around 3.6-3.7V, as the internal stresses are insignificant at that voltage level. |
| 01:26 | The good news is that it appears that most battery wear seems to take out around 15-20% of the battery's capacity, and after that, the capacity degradation slows incredibly, and the life of the battery will stay fairly constant for many years to come. |
| 01:39 | With that said, aggressively thrashing a battery and discharging it at the limit of its ability will of course wear it out faster, as will repeatedly charging the battery at multi-C rates. |
| 01:48 | Crucially, one of the worst things we can do to damage a battery is to keep it at a high state of charge while in storage, especially at an elevated temperature. |
| 01:55 | Either is bad, but in combination it's a real killer. |
| 01:59 | So, keeping within the battery's happy temperature and not leaving it at a high state of charge for extended periods of time will pay dividends in the long run. |
| 02:06 | The final big killer is overcharging a battery above its rated maximum. |
| 02:10 | This will very quickly damage the battery, and not just reduce its capacity, but also present a serious safety hazard. |
| 02:16 | So, to reiterate, modern EVs do a great job of protecting their batteries, and that's why they last so many times longer than the consumer electronics batteries you're used to dying after only a couple of years. |
| 02:27 | The biggest killers of battery health are excessive time at high temperatures while at a high state of charge, and aggressive charging and discharging when the battery is cold. |
