Secondary battery, battery pack, vehicle, and stationary power supply
摘要
說明書
In the secondary battery according to the first embodiment, water contained in the solvent of the aqueous electrolyte can be electrolyzed inside the negative electrode and near the negative electrode in the initial charge. This is because, during the initial charge, lithium ions are inserted in the negative electrode active material, and the potential of the negative electrode thus lowers. If this negative electrode potential becomes lower than the hydrogen generation potential, some water is decomposed into hydrogen (H2) and hydroxide ions (OH?) inside the negative electrode and near the negative electrode. Accordingly, pH of the aqueous electrolyte existing inside the negative electrode and near the negative electrode rises.
The hydrogen generation potential of the negative electrode depends on the pH of the aqueous electrolyte. That is, when the pH of the aqueous electrolyte which is in contact with the negative electrode becomes high, the hydrogen generation potential of the negative electrode lowers. Hence, after the initial charge, decomposition of water in the negative electrode becomes hard to occur.
