System, method, and program for predicting state of battery

A computer readable storage medium tangibly embodying a computer readable program code having computer readable instructions which, when implemented, cause a computer to carry out the steps of a method comprising:

• preparing a table of variables for use in recording an aging degradation ratio at each of different SOCs and each of different temperatures;
• preparing a table of variables for use in recording a current-carrying degradation ratio at each of different SOCs and each of different temperatures;
• receiving data that contains a length of stay of the battery at each of different SOCs and each of different temperatures in a predetermined period, a current-carrying amount in the battery at each of different SOCs and each of different temperatures in the predetermined period, an initial capacity retention ratio in the predetermined period, and a last capacity retention ratio in the predetermined period;
• calculating a degradation speed coefficient by applying a computational expression of a given model for the battery to data on the initial capacity retention ratio in the predetermined period and on the last capacity retention ratio in the predetermined period;
• and
• determining a linear sum model expression of a linear sum, a value of the aging degradation ratio, and a value of the current-carrying degradation ratio and storing the data in the tables, the linear sum being a sum of a value in which a product of each of the variables for use in recording the aging degradation ratio and each of the lengths of stay of the battery is added together at each of different SOCs and each of different temperatures and a value in which a product of each of the variables for use in recording the current-carrying degradation ratio and each of the current-carrying amounts in the battery is added together at each of different SOCs and each of different temperatures, the value of the aging degradation ratio and the value of the current-carrying degradation ratio being determined at each SOC and each temperature so as to reduce a difference between the degradation speed coefficients, wherein an arrangement of the aging degradation ratios and an arrangement of the current-carrying degradation ratios are usable in later prediction of the degradation of the battery.

A computer implemented system for predicting degradation of a battery, the system comprising:

• a storage unit;
• a table of variables for use in recording an aging degradation ratio at each of different SOCs and each of different temperatures and a table of variables for use in recording a current-carrying degradation ratio at each of different SOCs and each of different temperatures, the tables being prepared in the storage unit;
• a unit configured to store data that contains a length of stay of the battery at each of different SOCs and each of different temperatures in a predetermined period, a current-carrying amount in the battery at each of different SOCs and each of different temperatures in the predetermined period, an initial capacity retention ratio in the predetermined period, and a last capacity retention ratio in the predetermined period;
• a unit configured to calculate a degradation speed coefficient by applying a computational expression of a given model for the battery to data on the initial capacity retention ratio in the predetermined period and the last capacity retention ratio in the predetermined period;
• and
• a unit configured to determine a linear sum model expression of a linear sum, a value of the aging degradation ratio, and a value of the current-carrying degradation ratio and configured to store the data in the tables, the linear sum being a sum of a value in which a product of each of the variables for use in recording the aging degradation ratio and each of the lengths of stay of the battery is added together at each of different SOCs and each of different temperatures and a value in which a product of each of the variables for use in recording the current-carrying degradation ratio and each of the current-carrying amounts in the battery is added together at each of different SOCs and each of different temperatures, the value of the aging degradation ratio and the value of the current-carrying degradation ratio being determined at each SOC and each temperature so as to reduce a difference between the degradation speed coefficients, wherein an arrangement of the aging degradation ratios and an arrangement of the current-carrying degradation ratios are usable in later prediction of the degradation of the battery.