US 12,140,639 B2
Measurement device, measurement method, and storage medium
Tadashi Kaga, Wako (JP); Yuki Tominaga, Wako (JP); and Mao Hori, Tokyo (JP)
Assigned to HONDA MOTOR CO., LTD., Tokyo (JP)
Filed by HONDA MOTOR CO., LTD., Tokyo (JP)
Filed on Feb. 22, 2023, as Appl. No. 18/112,529.
Claims priority of application No. 2022-038080 (JP), filed on Mar. 11, 2022.
Prior Publication US 2023/0288486 A1, Sep. 14, 2023
Int. Cl. G01R 31/3842 (2019.01); H01M 10/42 (2006.01); H02J 7/00 (2006.01)
CPC G01R 31/3842 (2019.01) [H01M 10/4285 (2013.01); H02J 7/0047 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A measurement device configured to measure a negative electrode SEI formation amount of a lithium ion battery, comprising:
a charge/discharge controller configured to perform charge/discharge control of the lithium ion battery;
a voltage measurement part configured to measure a discharge voltage of the lithium ion battery;
a current measurement part configured to measure a discharge current of the lithium ion battery;
a discharge time measurement part configured to measure a discharge time of the lithium ion battery;
a storage configured to store measurement results of the voltage measurement part, the current measurement part and the discharge time measurement part; and
a calculation part configured to calculate a negative electrode SEI formation amount of the lithium ion battery,
wherein the calculation part causes a computer to:
acquire an initial positive electrode Ah-OCP curve and an initial negative electrode Ah-OCP curve by using a dV/dQ curve and charge/discharge curve fitting on the basis of results of the voltage measurement part, the current measurement part, and the discharge time measurement part that are read from the storage,
calculate a shrinkage factor (%) from an initial value for each of the positive electrode and the negative electrode,
calculate a positive electrode Ah-OCP curve and a negative electrode Ah-OCP curve to which only a shrinkage factor is applied in which the positive electrode Ah-OCP curve and the negative electrode Ah-OCP curve being calculated by multiplying the shrinkage factor (%) with respect to the initial positive electrode Ah-OCP curve and the initial negative electrode Ah-OCP curve while having a fixed point (electric potential) derived from the initial positive electrode Ah-OCP curve and the initial negative electrode Ah-OCP curve under a durability condition set as a reference,
calculate a deviation Z of Ah between a fixed point of the positive electrode Ah-OCP curve to which only the shrinkage factor is applied and a fixed point of a post-deterioration positive electrode Ah-OCP curve calculated by a dV/dQ curve and charge/discharge curve fitting,
calculate a deviation A of Ah between a fixed point of the negative electrode Ah-OCP curve to which only the shrinkage factor is applied and a fixed point of a post-deterioration negative electrode Ah-OCP curve calculated by a dV/dQ curve and charge/discharge curve fitting, and
calculate a negative electrode SEI formation amount as A−Z (A minus Z).