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Stability and safety of lithium batteries

Energy Storage

Last Post by batalto 4 years ago

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Mars

(@editor)

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Topic starter 11/07/2021 9:57 am

We recently reviewed a battery-operated ride on mower, and have received a few words of warning about how unstable (and potentially dangerous) lithium batteries can be when they get cold. I always take this feedback with a pinch of salt, but I've always known that batteries don't like cold, and I was wondering what the takeaway is for homeowners with battery storage (and EVs for that matter). Do you see a massive drop off on recharges during cold weather?

I'm really interested to learn more on this.

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Kev M

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11/07/2021 10:25 am

@editor, Lithium batteries perform less well at hot and cold extremes but I think the serious problems occur (i.e. damage) when rapid charging takes place repeatedly at very low temperatures. This isn't likely in a home battery system (because the batteries are normally indoors) or a mower (because grass doesn't grow when it's that cold!). EVs that are used all year round will suffer some range loss when it's cold and their battery management systems should slow down charging to protect the batteries.

This post was modified 4 years ago by Kev M

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Mars

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Topic starter 12/07/2021 10:18 am

Thanks @kev-m. So is the sole issue that they don't recharge fully or only partially, and does this lead to battery damage in the long-term? I've also heard that in some circumstances, when batteries are cold and are recharged they can ignite. I imagine this must be quite rare.

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Kev M

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12/07/2021 8:56 pm

@editor, Mars, I'm at about the limit of my knowledge here but as I understand it, they recharge fully but slower, but a full charge doesn't deliver as much energy when it's cold because the chemistry at work isn't as efficient at lower temps. So to deliver the same regular amount of energy when it's cold you'd need more charging cycles, which theoretically would wear the battery out quicker.

I'm not sure about fires but I also think they must be rare.

This post was modified 4 years ago by Kev M

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batalto

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13/07/2021 2:01 pm

I personally have FePO batteries which are different to the ones you are talking about and are better suited to energy storage. FePO are more stable, but less energy dense and heavier, this is better for home storage but obviously worse for vehicles. FePO are also more stable and have longer cycle lives but much less grunt output, again great for homes bad for cars.

https://blog.epectec.com/lithium-iron-phosphate-vs-lithium-ion-differences-and-advantages

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