CN-122017589-A - Solid-state battery power state estimation method and device based on expansion stress limitation

CN122017589ACN 122017589 ACN122017589 ACN 122017589ACN-122017589-A

Abstract

The invention provides a solid-state battery power state estimation method and device based on expansion stress limitation, which are applied to a solid-state battery and comprise the steps of constructing an expansion and contraction strain model and an expansion and contraction stress model to determine an equivalent stress model according to the expansion and contraction strain model, the expansion and contraction stress model and an ampere-hour integration method; the method comprises the steps of constructing an electromechanical coupling model for outputting current expansion stress, terminal voltage and current SOC based on an equivalent stress model and an equivalent circuit model, determining a first current range based on the current expansion stress, obtaining a second current range based on current SOC limitation, a third current range based on terminal voltage limitation and a working current range, solving intersection of the first current range, the second current range, the third current range and the working current range to obtain a continuous peak current estimated value, and obtaining continuous peak power based on the continuous peak current estimated value, the terminal voltage and the working power range. The scheme fully considers the mechanical effect of the solid-state battery, and improves the accuracy of the power estimation of the solid-state battery, the safety and the reliability of battery management.

Inventors

YANG SHICHUN
ZHANG HAOBO
SUN YEFAN
Liu Xuanzhuo
ZHU XIAOPENG
YAN XIAOYU
CAO YAOGUANG
CHEN FEI
LI YALUN
CAO RUI

Assignees

北京航空航天大学

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. A method for estimating the power state of a solid-state battery based on expansion stress limitation, which is applied to the solid-state battery, comprising: Constructing a swelling strain model and a swelling stress model to determine an equivalent stress model according to the swelling strain model, the swelling stress model and an ampere-hour integration method; the electromechanical coupling model is used for outputting the current expansion stress, terminal voltage and current SOC based on battery operation data; Determining a first current range based on the current expansion stress, and acquiring a second current range based on the current SOC limit, a third current range based on the terminal voltage limit and a working current range; intersection is obtained on the first current range, the second current range, the third current range and the working current range, and a continuous peak current estimated value is obtained; And obtaining continuous peak power based on the continuous peak current estimated value, the terminal voltage and the working power range.
2. The method of claim 1, wherein the constructing a model of the compressive strain and a model of the compressive stress comprises: And constructing a swelling strain model based on the swelling strain, the SOC and the battery temperature of the solid-state battery, wherein the swelling strain model is determined by the following formula: Wherein, the Is said compressive strain; Is the SOC deformation coefficient; Is the temperature coefficient; is the current SOC; is an initial SOC; is the current battery temperature; is the initial battery temperature; And constructing an expansion stress model based on the expansion stress and the expansion shrinkage strain of the solid-state battery, wherein the expansion stress model is determined by the following formula: Wherein, the Is the expansion stress; Is the stress coefficient of the battery; is the expansion and contraction stress coefficient of the battery.
3. The method of claim 1, wherein the equivalent stress model is determined by the formula: where k is the kth sample, Is the sampling interval; 、 expansion stress of the solid-state battery in the k+1th sampling and the k sampling respectively; Is a first coefficient; is a second coefficient; Current at the kth sampling; Is the stress coefficient of the battery; Is the SOC coefficient; the battery capacity at the kth sampling; And/or the number of the groups of groups, In the electromechanical coupling model: substituting the battery operation data and the expansion stress at the previous moment into an equivalent circuit model to obtain the SOC and the terminal voltage at the previous moment; substituting the SOC at the previous moment into the equivalent stress model to obtain the current expansion stress, and feeding back the current expansion stress to the equivalent circuit model to obtain the current SOC.
4. The method of claim 1, wherein the determining a first current range based on the present expansion stress comprises: Acquiring a working stress range of the solid-state battery, wherein the current expansion stress is positioned in the working stress range; when the excitation of the current in a plurality of continuous sampling periods is a constant value, correcting the equivalent stress model to obtain a continuous stress model; calculating to obtain the first current range based on the working stress range, the current expansion stress and the continuous stress model; Preferably, the continuous stress model is determined by the following formula: where k is the kth sample, Is the number of sampling periods; Stress prediction values of the solid-state battery in n continuous sampling periods; expansion stress at the kth sampling; Is a first coefficient; C is a third coefficient; Current at the kth sampling; The first current range is determined by the following formula: Wherein, the 、 Discharging current and charging current in the first current range in the process from the kth sampling to the kth+n sampling respectively; 、 Respectively minimum working stress and maximum working stress in the working stress range.
5. The method of claim 1, wherein the continuous peak current estimate is determined by the formula: Wherein, the 、 Charging current and discharging current of the continuous peak current estimated value in the sampling process from the kth time to the kth+n time; 、 the minimum working current and the maximum working current of the solid-state battery are respectively; 、 discharging current and charging current in the first current range in the process from the kth sampling to the kth+n sampling respectively; 、 charging current and discharging current in the third current range in the process from the kth sampling to the kth+n sampling respectively; 、 and the charging current and the discharging current of the second current range are respectively in the process from the kth sampling to the kth+n sampling.
6. The method according to any one of claims 1 to 5, wherein said deriving continuous peak power based on said continuous peak current estimate, said terminal voltage and an operating power range comprises: multiplying the continuous peak current estimated value with the terminal voltage to obtain a current power range; and obtaining the continuous peak power by solving an intersection of the current power range and the working power range.
7. A solid state battery power state estimation device based on expansion stress limitation, comprising: The construction module is used for constructing a swelling and shrinking strain model and a swelling and shrinking stress model so as to determine an equivalent stress model according to the swelling and shrinking strain model, the swelling and shrinking stress model and an ampere-hour integration method; the coupling module is used for constructing an electromechanical coupling model based on the equivalent stress model and the equivalent circuit model, and the electromechanical coupling model is used for outputting the current expansion stress, the terminal voltage and the current SOC based on the battery operation data; The current estimation module is used for determining a first current range based on the current expansion stress, acquiring a second current range based on the current SOC limit, a third current range based on the terminal voltage limit and a working current range, and acquiring continuous peak current estimation values by intersecting the first current range, the second current range, the third current range and the working current range; and the power estimation module is used for obtaining continuous peak power based on the continuous peak current estimated value, the terminal voltage and the working power range.
8. A computing device comprising a memory and a processor, the memory having stored therein a computer program, the processor implementing the method of any of claims 1-6 when the computer program is executed.
9. A computer readable storage medium having stored thereon a computer program which, when executed in a computer, causes the computer to perform the method of any of claims 1-6.
10. A computer program product comprising computer instructions which, when executed by a processor, implement the steps of the method of any of claims 1-6.

Description

Solid-state battery power state estimation method and device based on expansion stress limitation Technical Field The present invention relates to the field of battery technologies, and in particular, to a method and an apparatus for estimating a power state of a solid-state battery based on expansion stress limitation. Background The power lithium ion battery has the outstanding advantages of high specific energy, high specific power, high cost performance, zero emission and the like, becomes a research focus in the field of new energy, is applied to the fields of automobiles, unmanned aerial vehicles, airplanes and the like, and has wide application prospect. The Battery performance is fully exerted to effectively improve the energy utilization rate and the reliability of the full-electric vehicle, so that how to efficiently utilize the lithium ion Battery and exert the optimal performance of the lithium ion Battery is very important, and the Battery state is monitored and managed in real time through a Battery management system (Battery MANAGEMENT SYSTEM, BMS), so that the endurance mileage of the Battery can be effectively improved, the use cost of the Battery is reduced, and the use safety of the Battery is ensured. The core of the BMS is to estimate the state of the battery, mainly including state of charge (SOC), state of health (SOH), and state of power (SOP), which is of great interest due to the energy supply related to steady-state and dynamic multi-operating conditions of the battery at various stages. SOP is defined as the ratio of the peak power to the rated power of the battery, the peak power of the battery is used for representing the limit charge-discharge capacity of the battery, the steady state and dynamic multi-working-condition energy supply of each stage of the battery is related, and accurate power information is helpful for realizing dynamic matching of each stage of the battery, so that the endurance mileage of the vehicle is prolonged. SOP is similar to engine displacement in conventional fuel-fired vehicles and can be used as an indicator for vehicle and battery power performance. However, unlike the displacement of the traditional fuel oil vehicle in measurement, the power state of the battery is often changed due to various factors such as ambient temperature, operation condition, electric quantity and health state of the battery, so that the battery can not be directly measured and is a hidden state quantity, and therefore, the SOP estimation of the battery still has challenges. The solid-state battery is used as the next-generation battery technology, adopts solid electrolyte to replace the traditional liquid electrolyte, and has the advantages of high energy density, high safety (such as avoiding liquid leakage and thermal runaway), long service life and the like. The existing peak power estimation method is only based on the constraint of voltage and SOC, and aiming at a solid-state battery system, the dynamic mechanical characteristics (the mechanical stress influences ion transmission due to the volume change in the charge and discharge process) of the solid-state battery system are often ignored, so that the safety use of the solid-state battery is difficult to ensure by the existing peak power estimation method. Disclosure of Invention In order to solve the problems, the embodiment of the invention provides a solid-state battery power state estimation method and device based on expansion stress limitation, which fully considers the stress-electrochemical coupling effect of a solid-state battery, improves the accuracy of solid-state battery peak power estimation and ensures the use safety and reliability of the solid-state battery. In a first aspect, an embodiment of the present invention provides a method for estimating a power state of a solid-state battery based on expansion stress limitation, which is applied to the solid-state battery, and includes: Constructing a swelling strain model and a swelling stress model to determine an equivalent stress model according to the swelling strain model, the swelling stress model and an ampere-hour integration method; the electromechanical coupling model is used for outputting the current expansion stress, terminal voltage and current SOC based on battery operation data; Determining a first current range based on the current expansion stress, and acquiring a second current range based on the current SOC limit, a third current range based on the terminal voltage limit and a working current range; intersection is obtained on the first current range, the second current range, the third current range and the working current range, and a continuous peak current estimated value is obtained; And obtaining continuous peak power based on the continuous peak current estimated value, the terminal voltage and the working power range. In a second aspect, an embodiment of the present invention further provides a solid-state battery power sta