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My company have thousands of new Li Ion battery that is stored in ambient temperature for 3 years. Middle management then decided to manufacture products with these batteries.

I had already tested them, their current capacity drop to 85% rated. Then the management guys blurt out batteries can be recondition again and can be use as new batteries.

We have one of our product catches fire and the contract manufacture blame the batteries that we put in are too old. Which is why the management guys want to "recondition" them. Is there such thing as reconditioning batteries or is just a myth?

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    \$\begingroup\$ You recondition them with a new sticker that represents the current capacity ratings. \$\endgroup\$ – Jeroen3 Aug 19 '17 at 10:55
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    \$\begingroup\$ Possible duplicate of Li-ion Battery Rejuvenation \$\endgroup\$ – Overmind Dec 8 '17 at 13:55
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    \$\begingroup\$ You'll probably want to do some extensive research or hire a battery consultant than ask here. \$\endgroup\$ – Voltage Spike Dec 10 '17 at 1:51
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Some Lead Acid batteries and Nickel-Cadmium cells can be reconditioned.

I have never seen such claims for Lithium based batteries.

Lithium based batteries age even when they're not used (as you found out). Some batteries suffer more from this than others ! Their chemical structure changes in a way that cannot be restored. So in my opinion the marketing guys talked nonsense.

To be absolutely sure ask the battery manufacturer about the shelf life of their batteries. They have an interest in selling you new batteries of course so they might be inclined to say you need new ones. So I'd ask them how long their batteries last in storage and how they need to be stored.

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  • \$\begingroup\$ Is it a chemical change? Not dendrite growth on the lithium? Well, maybe not dendrites, but some physical that makes the lithium less reactive? \$\endgroup\$ – uhours Aug 18 '17 at 15:49
  • \$\begingroup\$ Is it a chemical change? That's what I remember reading/hearing somewhere. It could be a physical effect as well or a combination of the two. I'm no expert on this. \$\endgroup\$ – Bimpelrekkie Aug 18 '17 at 17:35
  • \$\begingroup\$ I believe it has something to do with the lithium ions being "absorbed" into the electrodes from the electrolyte, reducing the ability of the electrolyte to carry the electrons. Although I am not a chemist, so I may be totally off base. I am kinda curious now though and may ask one of our chemical engineers.... \$\endgroup\$ – Redja Aug 18 '17 at 20:10
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This is a myth. NiMH batteries I believe can be reconditioned but Li-ion cannot. We store our cells in a controlled environment at a specific state of charge after they are manufactured before being installed in batteries. I would guess that the reason for the capacity being lowered isn't due to the fact that they were stored for 3 years, but most likely because they weren't properly monitored.

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  • \$\begingroup\$ What do you mean "properly monitored"? If you store something, this means "not monitored", by definition. \$\endgroup\$ – Ale..chenski Aug 18 '17 at 22:48
  • \$\begingroup\$ Li-ion cells have some leakage to them, and if they were just thrown in a warehouse, they would deteriorate over time, especially if it was hot. Li-ion cells should be stored at 20-25C and kept around 40% SOC. A lot of damage can occur in there years, especially since most consumer cells have a relatively high leak rate in most cases. TL;DR: You can't throw li-ion cells in the "garage" for 3 years and expect them to work just as good as the day you put them there. \$\endgroup\$ – Redja Aug 20 '17 at 3:21
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Your management guy has got a bad case of pointy hair syndrome. Li ion batteries, as currently produced by quality manufactures (many fewer than you might imagine) are often specifically not warranted by the original manufacture for longer than 6 months after shipment. These cells use changing varieties of "electrolyte" (a sort of witch's brew of largely organic solvents + helpful contaminants), and without specific knowledge of the detailed nature (and generally microsturcture) of the electrodes AND the precise nature of the electrolyte brew, it is not possible to say anything whatsoever about risks of long term storage or reuse. In the case of Li ion battery cells storage below certain voltages (dependent on the contents of the cell) or above certain voltages will permanently damage electrode microstructures, and this damage will permanently reduce performance and safety margin. A reasonable test (but not guaranteed useful in all cases) might be to determine the internal resistance when discharged and when charged. This may be a useful hint. Or not. The point of the manufacture's data sheet with regard to charging and use, is to avoid these damaging conditions and to extend working life. Not all battery management circuits do this (as specified in the data sheet for the cell) and some are simply fraudulent. Even a proper battery management circuit will not be acceptable for use with this kind of Li ion cell, but not with this other. If this is not properly done, even a brand new cell might be dangerous or suffer performance deterioration.

These are much more capable (size, energy density, ...) than any other sort of commonly available battery, that they are very tempting. They are not as simple as flooded lead acid batteries, like the ones in vehicles for the last 100 years.

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