Method for determining state of charge of battery, battery management system, and electric apparatus

A method for charging a battery, comprising:

• performing charging of the battery;
• measuring a flow direction of a charging current;
• determining that the battery is in a charging state on a basis of the measured flow direction of the charging current by a battery management system;
• measuring a state of charge of the battery at a sampling time point tn;
• determining that the state of charge of the battery at the sampling time point tn is greater than or equal to a preset state of charge threshold;
• measuring a voltage Vn, a temperature Tn, and a charging rate Cn of the battery at the sampling time point tn, and a voltage Vi of the battery at a sampling time point ti, and acquiring a voltage difference Vn−Vi between the voltage Vn and the voltage Vi, wherein the sampling time point ti is a time point at which a state of charge of the battery is acquired within a preset time period before the sampling time point tn;
• determining that the voltage difference Vn−Vi is greater than or equal to a preset voltage threshold, and acquiring a voltage change rate based on the voltage difference Vn−Vi and a time difference tn−ti between the sampling time point tn and the sampling time point ti;
• and
• acquiring a voltage change rate threshold-state of charge query table which includes correspondences between corrected states of charge, and temperatures, and charging rates of the battery;
• determining that the voltage change rate is greater than or equal to a preset voltage change rate threshold, and acquiring a corrected state of charge of the battery as an actual state of charge of the battery based on the correspondences between corrected states of charge, and the preset voltage change rate threshold, temperatures, and charging rates of the battery based on the temperature Tn and the charging rate Cn of the battery at the sampling time point tn;
• and
• stopping the charging of the battery and determining that the battery is not in the charging state when the corrected state of charge of the battery is greater than a preset charging threshold.