Battery management system and a battery management method with a plurality of constant current charging stages for a battery

A battery management system, comprising:

• a sensing unit configured to generate a sensing signal indicating a voltage and a current of a battery;
• a memory unit configured to store a reference charging map for constant-current charging using first to mth reference current rates (C-rates), wherein m is a natural number of 2 or greater;
• and
• a control unit configured to determine a start value indicating a charge factor of the battery at a time point at which a charge command is received based on the sensing signal in response to the charge command being received,
• wherein the control unit is configured to:
• generate first to mth reference charge functions corresponding to the first to mth reference C-rates in a one-to-one relationship from the reference charging map, wherein each reference charge function indicates an adjustable charge factor increase and an adjustable changeover value as a function of the start value, wherein the charge factor increase is an amount of electrical energy stored in the battery that increases while the battery is charged at the corresponding reference C-rate of the reference charge function, and wherein the changeover value is a maximum charge factor at which the battery is charged at the corresponding reference C-rate of the reference charge function,
• and
• when a charge cycle including the constant-current charging starts:
• for each reference charge function, determine the changeover value of the reference charge function based on the start value, and
• control a charge current supplied to the battery using the first to mth reference C-rates in a sequential order based on the sensing signal, and the first to mth reference charge functions.