BATTERY DEGRADATION EVALUATION SYSTEM, BATTERY DEGRADATION EVALUATION METHOD, AND NON-TRANSITORY STORAGE MEDIUM STORING BATTERY DEGRADATION EVALUATION PROGRAM

A battery degradation evaluation system includes a memory and a processor. The processor is configured to acquire state quantities of a battery mounted at a vehicle, derive probabilities, and evaluate degradation of the battery based on the derivation results. The probabilities are a short-term degradation probability of the battery degrading in a pre-specified short period, a medium-term degradation probability of the battery degrading in a period that is longer than the short period, and a long-term degradation probability of the battery degrading in a period that is longer than the medium period. When a number of the state quantities is smaller, the processor sets a higher weighting for a combined degradation probability for the short period and medium period, which is calculated from the long-term degradation probability. When the number of state quantities is larger, the processor sets a higher weighting for the short-term degradation probability.