CN-121978543-A - Vehicle battery internal resistance health degree estimation method and device, controller and vehicle

CN121978543ACN 121978543 ACN121978543 ACN 121978543ACN-121978543-A

Abstract

The application provides a method and a device for estimating the health degree of battery internal resistance of a vehicle, a controller and the vehicle. The method comprises the steps of obtaining a plurality of impedance spectrums and a plurality of pulse test data of a battery of a vehicle, obtaining a first internal resistance of the battery at a preset reference temperature and a reference SOC according to the plurality of impedance spectrums, obtaining a second internal resistance of the battery at the reference temperature and the reference SOC according to the plurality of pulse test data, and calculating the internal resistance health of the battery according to the first internal resistance and the second internal resistance. The method is used for accurately estimating the internal resistance of the battery, improving the accuracy of estimating the health degree of the internal resistance of the battery, and further optimizing the effect of various performances of the vehicle.

Inventors

HAN KANG
LIU LIN
CHEN CHEN
WU QINGPING
JIANG YUNQI
WAN DONG
ZHANG DEWANG

Assignees

浙江吉利控股集团有限公司
吉利汽车研究院（宁波）有限公司

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (13)

1. A method of estimating the health of a battery of a vehicle, comprising: The method comprises the steps of acquiring a plurality of impedance spectrums and a plurality of pulse test data of a battery of a vehicle, wherein the plurality of impedance spectrums are obtained by carrying out EIS (electronic impedance spectroscopy) test on the battery for a plurality of times when the battery of the vehicle is in a standing state and under different test conditions; Acquiring a first internal resistance of the battery at a preset reference temperature and a reference SOC according to the plurality of impedance spectrums; acquiring a second internal resistance of the battery at the reference temperature and the reference SOC according to the plurality of pulse test data; and calculating the internal resistance health degree of the battery according to the first internal resistance and the second internal resistance.
2. The method of claim 1, wherein calculating the internal resistance health of the battery based on the first internal resistance and the second internal resistance comprises: Acquiring a first internal resistance health of the battery according to the first internal resistance and an initial first internal resistance, wherein the initial first internal resistance is acquired according to the first internal resistance of the battery at the reference temperature and the reference SOC, which is acquired at an initial stage after the vehicle is put into use; obtaining a second internal resistance health of the battery according to the second internal resistance and an initial second internal resistance, wherein the initial second internal resistance is obtained according to the second internal resistance of the battery at the reference temperature and the reference SOC, which is obtained at an initial stage after the vehicle is put into use; and fusing the first internal resistance health degree and the second internal resistance health degree to obtain the internal resistance health degree of the battery.
3. The method of claim 2, wherein the obtaining the first internal resistance health of the battery based on the first internal resistance and the initial first internal resistance comprises: acquiring a first internal resistance average value obtained by the test according to the first internal resistance and a first internal resistance average value of the battery obtained by the last test, wherein the first internal resistance average value obtained by each test is obtained according to the first internal resistance obtained by the test, the first internal resistance average value obtained by the last test and the number of health tests; comparing the first internal resistance average value with an initial first internal resistance to obtain a first internal resistance health degree of the battery; Correspondingly, the obtaining the second internal resistance health of the battery according to the second internal resistance and the initial second internal resistance includes: Obtaining a new second internal resistance average value according to the second internal resistance and a second internal resistance average value of the battery obtained by the last test, wherein the second internal resistance average value obtained by each test is obtained according to the second internal resistance obtained by the current test, the second internal resistance average value obtained by the last test and the number of health degree tests; and comparing the new second internal resistance average value with the initial second internal resistance to obtain the second internal resistance health of the battery.
4. The method of claim 2, wherein the fusing the first internal resistance health and the second internal resistance health to obtain the internal resistance health of the battery comprises: And based on a Kalman filter, fusing the first internal resistance health degree and the second internal resistance health degree to obtain the internal resistance health degree of the battery.
5. The method of any one of claims 1 to 4, wherein obtaining a plurality of impedance spectra of a battery of a vehicle comprises: Under each test condition, controlling to send each excitation condition to a DCDC controller according to a plurality of preselected excitation conditions, so that the DCDC controller applies alternating current excitation to the battery, wherein the energy required by the DCDC controller when applying the alternating current excitation is alternately provided by the battery and a 12V power supply, and each excitation condition comprises an excitation frequency and the duration of the excitation frequency; Collecting voltage time sequence data and current time sequence data of the battery in the process of applying alternating current excitation to the battery; And performing frequency domain conversion on the voltage time sequence data and the current time sequence data to obtain an impedance spectrum corresponding to the test condition.
6. The method of any one of claims 1 to 4, wherein the obtaining a first internal resistance of the battery at a preset reference temperature and reference SOC from the plurality of impedance spectrums comprises: for each test condition, acquiring a first internal resistance of the battery under the test condition according to an impedance spectrum corresponding to the test condition; For each SOC in the test conditions, adopting first internal resistances obtained by testing at different battery temperatures, and carrying out normalization processing on the temperatures to obtain the first internal resistances of the battery at the SOC and the reference temperature; and normalizing the SOC according to the first internal resistances of the battery at different SOCs and reference temperatures to obtain the first internal resistances of the battery at the reference SOCs and the reference temperatures.
7. The method of any one of claims 1 to 4, wherein each pulse of test data includes a current change and a voltage change; the obtaining, according to the plurality of pulse test data, a second internal resistance of the battery at the reference temperature and the reference SOC, including: Aiming at each test condition, acquiring a second internal resistance of the battery under the test condition according to the current change and the voltage change corresponding to the test condition; For each SOC in the test conditions, adopting second internal resistances obtained by testing at different battery temperatures, and carrying out normalization processing on the temperatures to obtain the second internal resistances of the battery at the SOC and the reference temperature; And normalizing the SOC according to the second internal resistances of the battery at different SOCs and reference temperatures to obtain the second internal resistances of the battery at the reference SOCs and the reference temperatures.
8. The method according to any one of claims 2 to 4, further comprising: calculating a first ratio of a difference value of a first internal resistance obtained by the test and a first internal resistance average value obtained by the last test to the number of health tests; And taking the sum of the first ratio and the first internal resistance average value obtained by the last test as the first internal resistance average value obtained by the current test.
9. The method according to any one of claims 2 to 4, further comprising: calculating a second ratio of a difference value of a second internal resistance obtained by the test and a second internal resistance average value obtained by the last test to the number of health tests; And taking the sum of the second ratio and the second internal resistance average value obtained by the last test as the second internal resistance average value obtained by the current test.
10. The method according to any one of claims 1 to 4, further comprising: and when the duration that the current of the battery is smaller than the preset current value is longer than the preset time, determining that the battery of the vehicle is in a standing state.
11. An estimation device of a battery internal resistance health degree of a vehicle, characterized by comprising: The system comprises a first acquisition module, a first detection module and a second acquisition module, wherein the first acquisition module is used for acquiring a plurality of impedance spectrums and a plurality of pulse test data of a battery of a vehicle, the plurality of impedance spectrums are obtained by carrying out EIS (electronic impedance spectroscopy) test on the battery of the vehicle for a plurality of times under the condition that the battery of the vehicle is in a standing state and under different test conditions, and the plurality of pulse test data are obtained by carrying out discharge pulse test on the battery for a plurality of times under the condition that the battery is in the standing state and under different test conditions, wherein the test conditions comprise battery temperature and SOC; The second acquisition module is used for acquiring a first internal resistance of the battery at a preset reference temperature and a reference SOC according to the plurality of impedance spectrums; A third acquisition module, configured to acquire a second internal resistance of the battery at the reference temperature and the reference SOC according to the plurality of pulse test data; And the calculation module is used for calculating the internal resistance health degree of the battery according to the first internal resistance and the second internal resistance.
12. A controller is characterized by comprising a memory and a processor; the memory stores computer-executable instructions; the processor executing computer-executable instructions stored in the memory, causing the processor to perform the method of any one of claims 1-10.
13. A vehicle comprising a vehicle body and the controller of claim 12.

Description

Vehicle battery internal resistance health degree estimation method and device, controller and vehicle Technical Field The present application relates to the field of batteries and the field of battery internal resistance estimation, and in particular, to a method and an apparatus for estimating the health of a battery internal resistance of a vehicle, a controller, and a vehicle. Background Along with the wide application of lithium ion batteries in electric automobiles, online accurate estimation of the internal resistance of the batteries becomes a key for guaranteeing the performance such as the vehicle power performance, the charging efficiency, the cruising ability and the like. The Battery management system (Battery MANAGEMENT SYSTEM, BMS) needs to dynamically monitor the change of the internal resistance of the Battery, evaluate the health degree of the Battery according to the change of the internal resistance, and optimize the Battery energy management strategy according to the evaluation result of the health degree, thereby prolonging the service life of the Battery and improving the running efficiency of the whole vehicle. At present, a commonly used method for estimating the internal resistance of a battery is to acquire battery cell aging data through an accelerated aging experiment in a laboratory environment in the research and development stage of the battery so as to establish an offline data table. After the vehicle is put into use, the internal resistance value of the current battery pack is estimated by looking up a table according to the collected working condition information of the battery. However, the aging process of the battery pack is affected by different environmental temperatures, vehicle mileage, driving habits and other driving conditions of each vehicle, so that the aging data of the battery cells tested in the research and development stage cannot truly reflect the aging state of each battery in the actual use process. In view of this, how to accurately estimate the internal resistance change of the battery of the vehicle in the use process on line, and further accurately estimate the internal resistance health of the battery, is a technical problem to be solved. Disclosure of Invention The embodiment of the application provides a method and a device for estimating the health degree of internal resistance of a battery, a controller and a vehicle, which are used for accurately estimating the internal resistance of the battery, improving the accuracy of estimating the health degree of the internal resistance of the battery and further optimizing the effects of various performances such as the power performance, the charging efficiency and the endurance of the vehicle. In a first aspect, an embodiment of the present application provides a method for estimating a health of a battery of a vehicle, including: The method comprises the steps of acquiring a plurality of impedance spectrums and a plurality of pulse test data of a battery of a vehicle, wherein the plurality of impedance spectrums are obtained by carrying out EIS (electronic impedance spectroscopy) test on the battery for a plurality of times when the battery of the vehicle is in a standing state and under different test conditions; Acquiring a first internal resistance of the battery at a preset reference temperature and a reference SOC according to the plurality of impedance spectrums; acquiring a second internal resistance of the battery at the reference temperature and the reference SOC according to the plurality of pulse test data; and calculating the internal resistance health degree of the battery according to the first internal resistance and the second internal resistance. In one possible implementation manner, the calculating the internal resistance health of the battery according to the first internal resistance and the second internal resistance includes: Acquiring a first internal resistance health of the battery according to the first internal resistance and an initial first internal resistance, wherein the initial first internal resistance is acquired according to the first internal resistance of the battery at the reference temperature and the reference SOC, which is acquired at an initial stage after the vehicle is put into use; obtaining a second internal resistance health of the battery according to the second internal resistance and an initial second internal resistance, wherein the initial second internal resistance is obtained according to the second internal resistance of the battery at the reference temperature and the reference SOC, which is obtained at an initial stage after the vehicle is put into use; and fusing the first internal resistance health degree and the second internal resistance health degree to obtain the internal resistance health degree of the battery. In one possible implementation manner, the obtaining the first internal resistance health of the battery according to the fir