How to make batteries last longer
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- Опубликовано: 30 май 2024
- Lithium-ion batteries generally lose their performance over time, however there are a number of steps we can take to make them last longer which we explore in this video and the science behind why each one works.
00:00 Introduction
00:23 Reduce time at high state-of-charge
02:15 Don't let the battery get too hot
03:08 Use slow charging
03:51 Avoid overcharging
05:02 Avoid overdischarge
05:42 Key points for a long lifetime battery
tl;dr
1. Reduce time at high state-of-charge (~85% is about right)
2. Don't let the battery get too hot (~20 °C is ideal)
3. Use slow charging (Fast charging can cause dendrites)
4. Don't overcharge (Battery will expand and bulge)
5. Don't overdischarge (Current collector will dissolve+cause short circuits)
Interested in learning more?
Here are some books which I recommend to learn more about the history of batteries and how they've impacted the world
📚 Volt Rush: The Winners and Losers in the Race to Go Green - Henry Sanderson - amzn.to/4aa81te (Amazon)
📚 The Powerhouse: America, China, and the Great Battery War - Steve LeVine - amzn.to/44O37kR (Amazon)
📚 Climate Capitalism: Winning the Global Race to Zero Emissions - Akshat Rathi - amzn.to/3JWmy0Q (Amazon)
#battery #lifetime #degradation
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🔋 Thanks Billy
One of the common problems I'm seeing is that to save costs manufacturers will use BMS that do not monitor every cell. Instead they will monitor groups of cells in series or parallel or both and I believe this is a common cause of non-mechanical battery failures, especially as cells age. Unfortunately BMS themselves are only as good as their features and design in the overall circuit/system.
Thanks for the comment, and yeah I agree with you that there are different quality BMSs out there with varying levels of reliability and functionality. Certainty, there are ones out there with the minimum level of functionality and reliability
Thank you, a clear and jargon free explanation. 👍🏻
Glad to hear it was useful
Thanks for the great video Doct Wu!
Glad you enjoyed it!
Great presentation, thank you for sharing.
Thanks
Can you give a rough idea of how fast is too fast for fast charging and battery degradation? Would you consider 1C to be too fast and contribute to degradation? Dendrite growth causing a short is not something that happens on modern consumer products, so it seems that charge rates are limited enough to prevent that failure mechanism. In your explanation the dendrites are using up the Li ions, so if we are not seeing shorts with fast charging, does this mean we are not seeing dendrite growth and degradation with 'fast charging', or are we just not getting long enough dendrites to create a short?
Good question. What defines fast will depend on the battery. There are batteries with higher energy density which is achieved by having thicker electrodes and thereby removing inactive material like current collectors. However the drawback to this is that the power capabilities normally drop as the lithium-ions have the travel further. The opposite is also true in that there are high power batteries with thin electrodes, but lower energy density. 1C is probably the right ball park for general fast charging limits, though this depends on the design. Some are targetting a 15 minute charge for extreme fast charging (XFC) which would be 4C. On your other point, whilst lithium plating can cause dendrite formation and short circuiting, sometimes you can get lithium-plating without short-circuiting. i.e. the lithium plates, but then reacts with the electrolyte to reduce the battery lifetime rather than cause catastrophic failure.
Only proves that companies that make products with non user serviceable batteries should have circuitry that prevents long times at full charge. Meaning once 100% charge is reached on the charger the device runs 100% on the charger power. They don’t though to push users to upgrade sooner
Yeah agree. State-of-charge is one of the main parameters we can change to extend lifetime but it a fine balance with available energy.
Thank You
Hope it was helpful
Is there any logic in claims I've seen that batteries "need" to be periodically fully discharged and then charged in order to stay healthy? Your vid leads me to believe otherwise, but I wanted to be 100% sure - thanks!
Not really. The only thing I can think of is overtime batteries will self-discharge which might lead to cell imbalances. Often charging back up will allow the battery management system to rebalance the cells (though depends on the BMS). This is something I've seen suggested in some LFP batteries where the purpose is potentially also to reset the state-of-charge estimation algorithm which can be a bit challenging in LFP cells. However, in general lithium-ion batteries don't need this type of cycling to stay healthy.
Great video, thanks a lot.
We are an NMP solvent focused on lithium batteries, which is one of the upstream raw materials for lithium battery production.
Glad you found it interesting
Is this transferrable to electric vehicle batteries too?
Definitely. Whilst the size and a few design details vary, the physics largely stay the same
I assume this is specific to lithium polymer batteries? It doesn't match my understanding of LFP batteries, for example. Their very flat voltage profile from 10%-90% SoC would make stopping at 80% very difficult, especially in batteries rather than single cells. And is it just that thermal runaway via polymer degradation in LFP is harder to trigger?
The exact numbers are chemistry specific but in general the higher the state-of-charge the more likely the anode (which is nearly always graphite in current commercial cells) will degrade. You're right that the flat profile in LFP makes SOC estimation more difficult, though not impossible. Also you're right that LFP is generally safer, since the material is less exothermic than nickel based cathodes and because it has a lower voltage, there is less change of electrolyte decomposition.
The whole industry should adapt the "85 is the new 100" mantra. Sadly today most consumer chargers and BMS are not smart enough to allow user control over the state of charge.
Agreed. This can significantly extend lifetime and is a shame that not all battery systems offer this flexibility
@@BillyWu trouble is some chemistry ages faster at 85% than at 95%
@@editorglueitcom True! Rules for optimised battery management systems are difficult to generalise and quite chemistry specific.
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