I recently pulled nine apparently healthy Samsung 26C cells out of a Dell laptop battery. While testing these cells I noticed that about half of them make a metallic clicking noise while being shaken vertically. Has anyone else noticed such behavior in any 18650 and does anyone have insight regarding the source? My first thought is that metal moving inside a cell is a bad thing and I should scrap the whole lot. Unfortunate because these cells appear to be in nearly new condition.
Interesting. A friend brought back a Sanyo ur18650fm cell to me once that stopped working when it fell (there was a dent at the negative end). It had a low voltage measurement (under 2V) and had something shaking inside. I heard the knocking particularly at the negative end. It would ‘start charging’ on the nitecore charger but would stop after a few minutes and register as ‘full’. Upon opening the cell,(tearing it apart with a pliars,) I saw a thin central tube not connected to anything which was causing the noise. I assumed this broke away from something and is what killed the cell.
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Do your shaking cells still work and charge properly?
Yup, I've had several, all pink Samsung cells from Dell packs, some of which randomly rattle. It sounds like a ball bearing loose inside. They all work fine though, but I'm phasing out these older cells in favor of some newer Sanyo pulls anyway.