BATTERY SYSTEM AND METHOD OF ESTIMATING POLARIZATION VOLTAGE OF SECONDARY BATTERY

• Main Author: SUGO, Yuki
• Format: Patent
• Language: English
• Published: 29.09.2022
• Subjects: BASIC ELECTRIC ELEMENTS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRIC EQUIPMENT OR PROPULSION OF ELECTRICALLY-PROPELLEDVEHICLES; ELECTRICITY; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES, IN GENERAL; GENERATION; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PERFORMING OPERATIONS; PHYSICS; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; SYSTEMS FOR STORING ELECTRIC ENERGY; TESTING; TRANSPORTING; VEHICLES IN GENERAL

A battery pack comprises a battery, a voltage sensor that detects a voltage of the battery, a power converter that transmits and receives electric power to and from the battery, an SMR and a charging relay electrically connected between the battery and the power converter, and a processor that estimates a polarization voltage Vp of the battery according to the following formula: Vp=a×{1−exp(-√t/b)}. The processor determines coefficients a and b based on first and second voltages. The first voltage is detected by the voltage sensor within a first period of time after the SMR is opened and the second voltage is detected by the voltage sensor within a second period of time before the charging relay is closed.