Li-ion cell dead

billr

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Does anybody here know what happens to a cell when it is fully discharged; what prevents it from taking any new charge? Any way to stuff electrons back in and revive it enough to start charging?

I am not talking about a cell or charger where discharge/charge is limited by a management system. I am talking about a single cell that has had a resistive load across the terminal long enough that the voltage is zero. I am playing with individual small 18650 cells, so don't worry too much about me burning the house down with any weird things you might suggest
 

paulo57509

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Back when I was into electric R/C car racing, I often heard about cell reversal (reversed polarity). IIRC, this would happen when the discharge load was continued to be applied after the battery past its cut-off voltage (allowing the voltage to approach zero). This was cited as a cause for a battery that no longer would take a charge.

I recall reading about giving a un-chargable battery a high voltage/high current jolt but I don't remember the details.

It's been +30 years so the memory has faded a bit.

It was standard practice to charge/discharge batteries; some used a discharge load of several 1157 bulbs in parallel; others used dedicated battery cyclers to avoid the reversal threshold. I've used both devices.
 

billr

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I am hoping there is some scheme to hit a cell with higher voltage, or maybe high dV/dT pulses, or AC to get it to start taking a charge. I have hit some individual cells with up to 60VDC, but no still no current will flow. I am reluctant to raise the DCV way up higher. I am wondering what the mechanical/chemical changes are when a cell goes to zero that prevent the chemical reactions needed for charging to take place.
 

paulo57509

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I went and looked through my filing cabinet, hard drive and binders and couldn't find any of my rechargeable battery references. If I come across them, I'll attach them.
 

nickb2

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ok late to game, but I wanted to make sure I covered the question which I think is this.

2.1 anode section may have your answer, quite a long read, but for was worth it, had never read this before.

I found this link to be very precis to what I have learned.

 

nickb2

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Back when I was into electric R/C car racing, I often heard about cell reversal (reversed polarity). IIRC, this would happen when the discharge load was continued to be applied after the battery past its cut-off voltage (allowing the voltage to approach zero). This was cited as a cause for a battery that no longer would take a charge.

I recall reading about giving a un-chargable battery a high voltage/high current jolt but I don't remember the details.
Wow is all I can say to this one, cause that is exactly what we did at montreal ev course before shutdown covid bs thing.

used rc li on chargers to revive cells .

. but now at my work, still trying to find a use for the autel ev kit we bought, it claims it can selectivly balance.

The BMS system has this option, still havent used it yet.

We have recycled a ton of old prius cells with the rc charger, some time you need to parralel them to spike, Chevy volt, not much success, as the battery is water cooled and any attempt to revive a cell lead to coolant leaks, cuz the three section unit is all pressed fit together, hoping the autel kit will help when time arises.

Fact, last year, had a volt in shop, dead.

but at this point, I must stop, cuz giving details on how to proceed, may lead to death.

highly suggest weber EV university. https://www.google.com/search?chann...ate=ive&vld=cid:58022057,vid:8-MNFgashpQ,st:0
 
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