Battery capacity estimation method, and battery module and electronic product using the same

A battery capacity estimation method being applied to a battery module comprising a battery and a control system and detecting a battery level of the battery of the battery module, wherein:

• the control system comprises a detection device connected to the battery, a storage and a processor;
• the detection device comprises a voltage measurement sensor and a temperature measurement sensor;
• the storage stores open circuit voltage (OCV) information and multiple design capacities, and the OCV information comprises an OCV table or a function corresponding to different temperatures, and the multiple design capacities are multiple battery capacities corresponding to different temperatures at a predetermined discharge C-rate;
• and
• the battery capacity estimation method comprises:
• charging the battery to a fully charged state for a predetermined period until the battery has entered a rest state without any charge current and any discharge current;
• measuring, by the voltage measurement device, an OCV and measuring, by the temperature measurement device, a temperature of the battery when the processor detects that the battery has entered the rest state;
• obtaining, by the processor, a state of charge (SOC) of the battery according to the OCV, by using the OCV table or the function corresponding to the temperature of the battery;
• obtaining a design capacity corresponding to the temperature at the predetermined discharge C-rate, according to the multiple design capacities;
• and
• calculating, by the processor, a QT of the battery according to the design capacity corresponding to the temperature and the SOC, wherein the QT represents an inherent capacity at the temperature.