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ReHab for Li-Ion Batteries?? Answered

Is it possible to get more life out of Lithium Ion batteries that no longer hold a charge? These things are great when new, but for the cost, they seem to crap out in a yr or 2.

Specifically, 18v Ryobi cordless tool batts.


For old power tool batteries you can open the case. The Ryobi battery I have has Torex screws with a center pin (Torex security screws). You would need a driver with a center hole to remove them.

Once you open the case you will probably find 5 to 6 battery cells wired in series (I have not taken mine apart). some of the cells may still be good. measure the voltages to identify the bad cell. Measure the size of the battery and then loolk at electronics supply company or battery catalogs to find batteries that match the size and voltage of a fully charged battery (there are multiple types of lithium batteries with slightly different output voltages. Buy the batteries you need and replace the failed cells with new ones.

As to rehabbing individual lithium cells it is not possible. In lithium batteries the electrolyte gradually breaks down into solid material that eventually prevents lithium from moving between the anode and cathode of the battery. The only way to correct that is to recycle it. for older NiCd batteries dendrite crystal formation was the big problem. Dendrites can be removed or reduced in NiCd with short high current pulses. These high pulses would melt the dendrites and could restore some capacity to the battery without overheating it.

Are the cells in these like the cells in Ni-cads? I've had nicad packs apart, and the cells resemble c-cells. I know the li-ion cells cant be as big, since the pack isn't. just wondering if the cells are similar in robustness, and such.

yes most battery packs are made from individual cells that often round cylinders. however sometimes you will see squar cells.

LI-Ion stands for LITHIUM Ion exchange.

As the name suggests the active material is metallic Lithium.

In the battery is an endless cycle of charge and discharge - and like anodizing the lithium changes the metallic properties during those cycles (in very simple words).

If you open a lithium battery you will expose the metal to air, which in turn wil oxidize it within seconds, let it get into contact with water or sweating fingers and you start a fire....

Don't mess with them, it is not worth the hassle.

There is no way to recondition the batteries yourself. But be sure to recycle the battery so the lithium can be reclaimed and used in a new battery.

sigh. yeah. that's what I thought. well, maybe i can sell the li-ion charger.