Information processing method and information processing device

The invention provides an information processing method and an information processing device capable of improving the utilization value of a battery. The information processing method includes: acquiring battery-related information related to a vehicle-mounted battery; diagnosing the degree of deterioration of the battery using the acquired battery-related information and a plurality of diagnosis methods for diagnosing the degree of deterioration of the battery; and outputting at least one of the diagnosed degradation degree and the transaction price of the battery corresponding to the degradation degree. 本发明提供一种能够提高电池的利用价值的信息处理方法和信息处理装置。信息处理方法包括：取得与车载用的电池有关的电池相关信息；使用所取得的电池相关信息和诊断电池的劣化程度的多个诊断方式，诊断电池的劣化程度；将诊断出的劣化程度和与所述劣化程度相应的所述电池的交易价格中的至少一者输出。