Manufacturing standards watchdog, Lumafield, recently completed a study of 1,000 lithium-ion batteries. The results revealed manufacturing defects in low-cost and counterfeit cells, that could potentially lead to fires and explosions. The message is clear. We should beware substandard lithium-ion chemistry hiding behind cheap prices and deceptive packaging.
Broad Study of Substandard Lithium-Ion Chemistry
Lumafield examined 1,000, size 18650, lithium-ion battery cells sourced from ten suppliers. These sources included three famous brands, three re-branded versions from specialist suppliers, and four low-cost or counterfeit suppliers operating solely on the internet.
Thirty-three of the sample batteries showed signs of deliberate ‘anode overhang’. This strategy provides a margin of error that increases tolerance to inconsistencies and imperfections. All of these lithium-ion batteries came from the rebranded specialists and low cost or counterfeit suppliers.
If we narrow the sample to only include the low cost or counterfeit batteries, then the need to beware substandard lithium-ion battery cells becomes even more pressing. The probability of purchasing a battery with anode overhang jumps to 8%.
The risk that innocent battery users face becomes even more extreme, if we narrow the sample further. Lumafield examined the results it obtained from counterfeit lithium-ion batteries, that claimed impossibly high performance standards. The probability of the defect occurring jumped from 12% to 15%.
More Reasons to Beware Cheap Counterfeit Lithium-ion
Most batteries contain several anode-electrolyte-cathode layers. If the batteries are round, then these layers are typically wound together in a jelly roll arrangement. However, if the batteries are flat, then the cells are likely to be layered, one on top of the other.
The edges of these layers should align precisely, as another indicator of manufacturing quality. Lumafield found evidence of some deviation among the rebranded batteries. But the defect was seven times more likely to occur among the low cost / counterfeit cells.
Those defects are not guarantees that a battery will explode or catch fire. But they do increase the probability that one might. There is sufficient cause to avoid purchasing batteries over the internet from suppliers we have no reason to trust. We should beware substandard lithium-ion batteries at all times.
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Preview Image: Dismantling a Jelly Roll Battery
