Article ID: TETSU-2024-102
In order to improve both performance and safety of lithium-ion batteries, we investigated the use of steel sheets which have a higher melting point than aluminum currently used for cell cases of lithium-ion batteries, for cell cases. First, a coating metal that can suppress Fe dissolution was selected, because corrosion resistance to battery electrolyte is important for battery cell cases. We found that Ni has high corrosion resistance to battery electrolyte, and that Ni-coated steel sheets can reduce the risk of short circuits due to decrease in Fe dissolution and re-deposition compared to non-coated steel sheets.
Next, the performance of the battery using Ni-coated steel sheet as the cell case was shown, and the discharge capacity after 500 cycles was the same as that of the battery using aluminum as the cell case, confirming that there is no problem with the battery performance.
For battery cell cases, it is also important to have superior high-temperature strength to suppress burnout in the event of thermal runaway. Ni-coated steel sheets have superior high-temperature strength compared to aluminum.
These characteristics of Ni-coated steel sheets are expected to be applied battery cell cases to produce batteries with superior performance and safety.
