Method and apparatus for estimating battery state of health

Abstract

Estimating a battery state of health (SOH) is described. The state of heath is estimated by obtaining a partial charge or discharge capacity of a target battery in a state of charge (SOC) interval of each of a plurality of SOCs. First dV/dSOC data is separately calculated for each SOC in an m th preset battery capacity based on the m th preset battery capacity and the partial charge or discharge capacity in the SOC interval of each SOC. A smallest overall dV/dSOC data deviation is determined from all overall dV/dSOC data deviations corresponding to M preset battery capacities. A preset battery capacity is determined corresponding to the smallest overall dV/dSOC data deviation as a retention capacity of an aged target battery. The retention capacity of the aged target battery is divided by a retention capacity of the target battery in a new battery state, to obtain the SOH estimate of the target battery.

What is claimed is: 
     
         1 . A method of estimating a state of health (SOH) of a battery, comprising:
 obtaining a partial charge or discharge capacity of the battery in each of a plurality of state of charge (SOC) ranges;   determining, based on the partial charge or discharge capacity of the battery in each SOC range of the plurality of SOC ranges, an overall dV/dSOC data deviation corresponding to each of M preset battery capacities of the battery to obtain overall dV/dSOC data deviations corresponding to the M preset battery capacities, where M is a positive integer; and   estimating the SOH of the battery based on a preset battery capacity corresponding to a smallest overall dV/dSOC data deviation in the overall dV/dSOC data deviations.   
     
     
         2 . The method according to  claim 1 , wherein the obtaining the partial charge or discharge capacity of the battery in each of the plurality of SOC ranges, comprises:
 obtaining the partial charge or discharge capacity of the battery in a first SOC range based on a coulombic efficiency of the battery, and a random current between a start moment of the first SOC range and an end moment of the first SOC range,   where the first SOC range is one of the plurality of SOC ranges.   
     
     
         3 . The method according to  claim 1 , wherein each of the plurality of SOC ranges starts with an SOC of a plurality of SOCs. 
     
     
         4 . The method according to  claim 1 , wherein the determining an overall dV/dSOC data deviation corresponding to each of M preset battery capacities, comprises:
 obtaining, based on a first preset battery capacity and the partial charge or discharge capacity of the battery in each of the plurality of SOC ranges, a first dV/dSOC data, where the first preset battery capacity is one of the M preset battery capacities;   obtaining, based on a dV/dSOC characteristic function and the first dV/dSOC data, a second dV/dSOC data; and   obtaining the overall dV/dSOC data deviation corresponding to the first preset battery capacity based on the first dV/dSOC data and the second dV/dSOC data.   
     
     
         5 . The method according to  claim 1 , wherein the estimating the SOH of the battery based on a preset battery capacity corresponding to a smallest overall dV/dSOC data deviation in the overall dV/dSOC data deviations corresponding to the M preset battery capacities, comprises:
 determining the preset battery capacity corresponding to the smallest overall dV/dSOC data deviation as a retention capacity of the battery in an aged state; and   determining the SOH of the battery based on the retention capacity of the battery in the aged state and a retention capacity of the battery in a new battery state.   
     
     
         6 . An apparatus, comprising
 a processor; and   a memory configured to store a computer execution instructions,   wherein the processor is configured execute the computer execution instructions to carry out the following:
 obtaining a partial charge or discharge capacity of a battery in each of a plurality of state of charge (SOC) ranges; 
 determining, based on the partial charge or discharge capacity of the battery in each SOC range, an overall dV/dSOC data deviation corresponding to each of M preset battery capacities of the battery to obtain overall dV/dSOC data deviations corresponding to the M preset battery capacities, where M is a positive integer; and 
 estimating the SOH of the battery based on a preset battery capacity corresponding to a smallest overall dV/dSOC data deviation in the overall dV/dSOC data deviations. 
   
     
     
         7 . The apparatus according to  claim 6 , wherein the obtaining the partial charge or discharge capacity of the battery in each of the plurality of SOC ranges, comprises:
 obtaining the partial charge or discharge capacity of the battery in a first SOC range based on a coulombic efficiency of the battery, and a random current between a start moment of the first SOC range and an end moment of the first SOC rang, where the first SOC range is one of the plurality of SOC ranges.   
     
     
         8 . The apparatus according to  claim 6 , wherein each of the plurality of SOC ranges starts with an SOC of a plurality of SOCs. 
     
     
         9 . The apparatus according to  claim 6 , wherein the determining an overall dV/dSOC data deviation corresponding to each of M preset battery capacities, comprises:
 obtaining, based on a first preset battery capacity and the partial charge or discharge capacity of the battery in each of the plurality of SOC ranges, a first dV/dSOC data, where the first preset battery capacity is one of the M preset battery capacities;   obtaining, based on a dV/dSOC characteristic function and the first dV/dSOC data, a second dV/dSOC data; and   obtaining the overall dV/dSOC data deviation corresponding to the first preset battery capacity based on the first dV/dSOC data and the second dV/dSOC data.   
     
     
         10 . The apparatus according to  claim 6 , wherein the estimating the SOH of the battery based on a preset battery capacity corresponding to a smallest overall dV/dSOC data deviation in the overall dV/dSOC data deviations corresponding to the M preset battery capacities, comprises:
 determining the preset battery capacity corresponding to the smallest overall dV/dSOC data deviation as a retention capacity of the battery in an aged state; and   determining the SOH of the battery based on the retention capacity of the battery in the aged state and a retention capacity of the battery in a new battery state.   
     
     
         11 . A non-transitory computer-readable storage medium, comprising a program, wherein the program is configured to be executed by a processor to carry out the following:
 obtaining a partial charge or discharge capacity of a battery in each of a plurality of state of charge (SOC) ranges;   determining, based on the partial charge or discharge capacity of the battery in each SOC range, an overall dV/dSOC data deviation corresponding to each of M preset battery capacities of the battery to obtain overall dV/dSOC data deviations corresponding to the M preset battery capacities, where M is a positive integer; and   estimating the SOH of the battery based on a preset battery capacity corresponding to a smallest overall dV/dSOC data deviation in the overall dV/dSOC data deviations.   
     
     
         12 . The non-transitory computer-readable storage medium according to  claim 11 , wherein the obtaining the partial charge or discharge capacity of the battery in each of the plurality of SOC ranges, comprises:
 obtaining the partial charge or discharge capacity of the battery in a first SOC range based on a coulombic efficiency of the battery, and a random current between a start moment of the first SOC range and an end moment of the first SOC range,   where the first SOC range is one of the plurality of SOC ranges.   
     
     
         13 . The non-transitory computer-readable storage medium according to  claim 11 , wherein each of the plurality of SOC ranges starts with an SOC of a plurality of SOCs. 
     
     
         14 . The non-transitory computer-readable storage medium according to  claim 11 , wherein the determining an overall dV/dSOC data deviation corresponding to each of M preset battery capacities, comprises:
 obtaining, based on a first preset battery capacity and the partial charge or discharge capacity of the battery in each of the plurality of SOC ranges, a first dV/dSOC data, where the first preset battery capacity is one of the M preset battery capacities;   obtaining, based on a dV/dSOC characteristic function and the first dV/dSOC data, a second dV/dSOC data; and   obtaining the overall dV/dSOC data deviation corresponding to the first preset battery capacity based on the first dV/dSOC data and the second dV/dSOC data.   
     
     
         15 . The non-transitory computer-readable storage medium according to  claim 11 , wherein the estimating the SOH of the battery based on a preset battery capacity corresponding to a smallest overall dV/dSOC data deviation in the overall dV/dSOC data deviations corresponding to the M preset battery capacities, comprises:
 determining the preset battery capacity corresponding to the smallest overall dV/dSOC data deviation as a retention capacity of the battery in an aged state; and   determining the SOH of the battery based on the retention capacity of the battery in the aged state and a retention capacity of the battery in a new battery state.