Battery cell stress-strain relation determination method and device and medium

Abstract

The invention discloses a battery cell stress-strain relation determination method and device and a medium, and the method comprises the steps: obtaining a first corresponding relation between the absolute thickness of a battery cell under zero pressure and the residual electric quantity of the battery cell, and obtaining a plurality of second corresponding relations between the absolute thickness of the battery cell under a plurality of pressures and the residual electric quantity of the battery cell, the pressure is in one-to-one correspondence with the second corresponding relation; acquiring a first absolute thickness corresponding to the target residual electric quantity from the first corresponding relation, and acquiring a second absolute thickness corresponding to the target residual electric quantity from each second corresponding relation; obtaining the strain of the battery cell under each pressure according to the first absolute thickness and the plurality of second absolute thicknesses; and according to the plurality of pressures and the strain under each pressure, obtaining a stress-strain relationship of the battery cell under the target residual electric quantity. According to the embodiment of the invention, the stress-strain relationship of the battery cell under the target residual electric quantity can be obtained, and the stress deformation capability of the battery cell can be analyzed conveniently.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device and medium for determining stress-strain relationship of a battery cell. Background Art

[0002] During the use of the battery cell, expansion force will be generated, and the positive and negative pole pieces will be deformed under the action of the expansion force, which will lead to problems such as reduced porosity and poor liquid phase transmission dynamics. Stress-strain curves are usually used to characterize the stress-deformation capacity of the battery cell. Currently, a method is urgently needed to determine the stress-strain relationship of the battery cell. Summary of the invention

[0003] The present application provides a method, device and medium for determining the stress-strain relationship of a battery cell, which are used to determine the strain of the battery cell under different stresses, thereby facilitating the analysis of the stress-deformation capacity of the battery cell.

[0004] In a first aspect, the present application provides a method for determining a stress-strain relationship of a battery cell, comprising:

[0005] Acquire a first correspondence between an absolute thickness of a battery cell at zero pressure and a remaining amount of power of the battery cell, and acquire multiple second correspondences between the absolute thickness of the battery cell at multiple pressures and the remaining amount of power of the battery cell, wherein the pressures correspond to the second correspondences one by one;

[0006] Acquire a first absolute thickness corresponding to a target remaining power from the first corresponding relationship, and acquire a second absolute thickness corresponding to the target remaining power from each of the second corresponding relationships;

[0007] Obtaining the strain of the battery cell under each of the pressures according to the first absolute thickness and the plurality of the second absolute thicknesses;

[0008] According to the multiple pressures and the strain under each pressure, the stress-strain relationship of the battery cell under the target remaining power is obtained.

[0009] In the embodiment of the present application, the stress-strain relationship of the battery cell under the target remaining power can be obtained. Through this relationship, the strain of the battery cell under different stresses can be obtained. The deformation of the battery cell can be obtained according to the strain, and the stress exerted on the battery cell can also be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress exerted on the battery cell.

[0010] In one embodiment of the present application, obtaining multiple second corresponding relationships between the absolute thickness of the battery cell under multiple pressures and the remaining power of the battery cell includes:

[0011] When a first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell are acquired, each of the data pairs comprising a remaining power of the battery cell and an absolute thickness of the battery cell under the first pressure, the remaining power in each of the data pairs being different, and the first pressure being any one of the plurality of pressures;

[0012] Data fitting is performed on the plurality of data pairs to obtain a second corresponding relationship corresponding to the first pressure.

[0013] In an embodiment of the present application, data fitting can be performed on a limited number of data pairs to obtain a second corresponding relationship corresponding to the first pressure, thereby improving the efficiency of obtaining the second corresponding relationship and facilitating subsequent acquisition of the stress-strain relationship of the battery cell at the target remaining power based on the second corresponding relationship.

[0014] In one embodiment of the present application, when the first pressure is applied to the battery cell, a plurality of data pairs obtained during the charging and discharging process of the battery cell are obtained, including:

[0015] Applying a first pressure to the battery cell and leaving it to stand for a preset time;

[0016] The battery cell is charged and discharged to obtain a plurality of data pairs.

[0017] In the embodiment of the present application, after the first pressure is applied to the battery cell, it is left to stand for a preset time so that the effect of creep on the thickness of the battery cell under the first pressure tends to be stable, thereby making the absolute thickness of the battery cell under the first pressure more accurate.

[0018] In one embodiment of the present application, the battery cell is charged and discharged to obtain a plurality of data pairs, including:

[0019] Performing a first charge and discharge process on the battery cell;

[0020] During the second charge-discharge process of the battery cell, a plurality of absolute thicknesses corresponding to a plurality of different remaining capacities of the battery cell are obtained, wherein the plurality of remaining capacities correspond to the plurality of absolute thicknesses in a one-to-one manner;

[0021] A plurality of data pairs are obtained according to the plurality of remaining capacities and the plurality of absolute thicknesses.

[0022] In the embodiment of the present application, performing the first charge and discharge treatment on the battery cell can stabilize the thickness expansion of the battery cell when performing the second charge and discharge treatment on the battery cell, thereby making the absolute thickness of the battery cell under the first pressure obtained more accurate.

[0023] In one embodiment of the present application, the absolute thickness of the battery cell under the first pressure is the sum of the absolute thickness of the battery cell under zero pressure, the creep thickness and the expansion thickness, wherein the creep thickness is the change in thickness of the battery cell when the first pressure is applied to the battery cell, and the expansion thickness is the expansion of the thickness of the battery cell when the battery cell is charged and discharged.

[0024] In an embodiment of the present application, when determining the absolute thickness of the battery cell under the first pressure, the creep thickness and the expansion thickness are added, and the influence of the battery cell creep on the change of the absolute thickness of the battery cell and the influence of the battery cell charging and discharging on the change of the absolute thickness of the battery cell are taken into consideration, thereby improving the accuracy of the calculation of the absolute thickness of the battery cell under the first pressure.

[0025] In one embodiment of the present application, obtaining the strain of the battery cell under each of the pressures according to the first absolute thickness and the plurality of the second absolute thicknesses includes:

[0026] Obtaining a difference between a second absolute thickness corresponding to a second pressure and the first absolute thickness, wherein the second pressure is any one of the plurality of pressures;

[0027] The strain of the battery cell under the second pressure is calculated according to the difference and the first absolute thickness.

[0028] In the embodiment of the present application, the strain of the battery cell under each of the pressures is obtained through the first absolute thickness and the plurality of the second absolute thicknesses, so as to facilitate the subsequent acquisition of the stress-strain relationship.

[0029] In one embodiment of the present application, the stress-strain relationship of the battery cell at the target remaining power is obtained according to the multiple pressures and the strain under each pressure, including:

[0030] Obtaining stress corresponding to the third pressure according to a third pressure and a stress-bearing area of ​​the battery cell when the third pressure is applied thereto, wherein the third pressure is any one of the plurality of pressures;

[0031] The stress corresponding to each of the third pressures is used as a first coordinate axis, and the strain corresponding to the third pressure is used as a second coordinate axis to obtain a curve for characterizing the stress-strain relationship of the battery cell under the target remaining power.

[0032] In an embodiment of the present application, a curve can be obtained to characterize the stress-strain relationship of a battery cell under a target remaining power. Through the curve, the strain of the battery cell under different stresses can be obtained, and the deformation of the battery cell can be obtained based on the strain. The stress exerted on the battery cell can also be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress exerted on the battery cell.

[0033] In a second aspect, an embodiment of the present application provides a device for determining a stress-strain relationship of a battery cell, comprising:

[0034] A first acquisition module, used to acquire a first corresponding relationship between an absolute thickness of a battery cell under zero pressure and a remaining power of the battery cell;

[0035] A second acquisition module, used for obtaining a plurality of second corresponding relationships between the absolute thickness of the battery cell under a plurality of pressures and the remaining power of the battery cell, wherein the pressures correspond to the second corresponding relationships in a one-to-one manner;

[0036] a third acquisition module, configured to acquire a first absolute thickness corresponding to a target remaining power from the first corresponding relationship, and to acquire a second absolute thickness corresponding to the target remaining power from each of the second corresponding relationships;

[0037] a fourth acquisition module, configured to obtain the strain of the battery cell under each of the pressures according to the first absolute thickness and a plurality of the second absolute thicknesses;

[0038] The fifth acquisition module is used to obtain the stress-strain relationship of the battery cell under the target remaining power according to the multiple pressures and the strain under each pressure.

[0039] In the embodiment of the present application, the stress-strain relationship of the battery cell under the target remaining power can be obtained. Through this relationship, the strain of the battery cell under different stresses can be obtained. The deformation of the battery cell can be obtained according to the strain, and the stress exerted on the battery cell can also be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress exerted on the battery cell.

[0040] In an embodiment of the present application, the second acquisition module includes:

[0041] a first acquisition submodule, configured to acquire, when a first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell, each of the data pairs comprising a remaining power of the battery cell and an absolute thickness of the battery cell under the first pressure, the remaining power in each of the data pairs being different, and the first pressure being any one of the plurality of pressures;

[0042] The fitting submodule is used to perform data fitting on the plurality of data pairs to obtain a second corresponding relationship corresponding to the first pressure.

[0043] In an embodiment of the present application, data fitting can be performed on a limited number of data pairs to obtain a second corresponding relationship corresponding to the first pressure, thereby improving the efficiency of obtaining the second corresponding relationship and facilitating subsequent acquisition of the stress-strain relationship of the battery cell at the target remaining power based on the second corresponding relationship.

[0044] In an embodiment of the present application, the first acquisition submodule includes:

[0045] A first unit, used for applying a first pressure to the battery cell and leaving it to stand for a preset time;

[0046] The second unit is used to charge and discharge the battery cell to obtain a plurality of data pairs.

[0047] In the embodiment of the present application, after the first pressure is applied to the battery cell, it is left to stand for a preset time so that the effect of creep on the thickness of the battery cell under the first pressure tends to be stable, thereby making the absolute thickness of the battery cell under the first pressure more accurate.

[0048] In one embodiment of the present application, the second unit includes:

[0049] A first subunit, used for performing a first charge and discharge process on the battery cell;

[0050] The second subunit is used to obtain a plurality of absolute thicknesses corresponding to a plurality of different remaining capacities of the battery cell during the second charge and discharge process of the battery cell, wherein the plurality of remaining capacities correspond to the plurality of absolute thicknesses in a one-to-one manner;

[0051] The acquisition subunit is used to obtain a plurality of the data pairs according to the plurality of remaining power and the plurality of absolute thicknesses.

[0052] In the embodiment of the present application, performing the first charge and discharge treatment on the battery cell can stabilize the thickness expansion of the battery cell when performing the second charge and discharge treatment on the battery cell, thereby making the absolute thickness of the battery cell under the first pressure obtained more accurate.

[0053] In one embodiment of the present application, the absolute thickness of the battery cell under the first pressure is the sum of the absolute thickness of the battery cell under zero pressure, the creep thickness and the expansion thickness, wherein the creep thickness is the change in thickness of the battery cell when the first pressure is applied to the battery cell, and the expansion thickness is the expansion of the thickness of the battery cell when the battery cell is charged and discharged.

[0054] In an embodiment of the present application, when determining the absolute thickness of the battery cell under the first pressure, the creep thickness and the expansion thickness are added, and the influence of the battery cell creep on the change of the absolute thickness of the battery cell and the influence of the battery cell charging and discharging on the change of the absolute thickness of the battery cell are taken into consideration, thereby improving the accuracy of the calculation of the absolute thickness of the battery cell under the first pressure.

[0055] In an embodiment of the present application, the fourth acquisition module includes:

[0056] A second acquisition submodule, used to acquire a difference between a second absolute thickness corresponding to a second pressure and the first absolute thickness, wherein the second pressure is any one of the multiple pressures;

[0057] The third acquisition submodule is used to calculate the strain of the battery cell under the second pressure according to the difference and the first absolute thickness.

[0058] In the embodiment of the present application, the strain of the battery cell under each of the pressures is obtained through the first absolute thickness and the plurality of the second absolute thicknesses, so as to facilitate the subsequent acquisition of the stress-strain relationship.

[0059] In an embodiment of the present application, the fifth acquisition module includes:

[0060] a fourth acquisition submodule, configured to obtain a stress corresponding to the third pressure according to a third pressure and a stress-bearing area of ​​the battery cell when the third pressure is applied thereto, wherein the third pressure is any one of the plurality of pressures;

[0061] The fifth acquisition submodule is used to obtain a curve characterizing the stress-strain relationship of the battery cell under the target remaining power, using the stress corresponding to each of the third pressures as the first coordinate axis and the strain corresponding to the third pressure as the second coordinate axis.

[0062] In an embodiment of the present application, a curve can be obtained to characterize the stress-strain relationship of a battery cell under a target remaining power. Through the curve, the strain of the battery cell under different stresses can be obtained, and the deformation of the battery cell can be obtained based on the strain. The stress exerted on the battery cell can also be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress exerted on the battery cell.

[0063] In a third aspect, an embodiment of the present application provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the method for determining the stress-strain relationship of a battery cell as described in the first aspect are implemented.

[0064] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0066] Figure 1 A schematic diagram of a process for determining a stress-strain relationship of a battery cell provided in an embodiment of the present application;

[0067] Figure 2 A schematic diagram of an absolute thickness curve of a battery cell under multiple pressures provided in an embodiment of the present application;

[0068] Figure 3 A schematic diagram of a thickness expansion curve of a battery cell during the charge and discharge process provided in an embodiment of the present application;

[0069] Figure 4 A schematic diagram of a stress-strain curve of a battery cell provided in an embodiment of the present application at 50% SOC;

[0070] Figure 5 A schematic diagram of the structure of a device for determining stress-strain relationship of a battery cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0072] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0073] The following will introduce in detail the method, device and medium for determining the stress-strain relationship of a battery cell provided in the embodiments of the present application in conjunction with the accompanying drawings.

[0074] Figure 1 A schematic diagram of a process for determining a stress-strain relationship of a battery cell provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the method includes steps 101 to 104, wherein:

[0075] Step 101, obtaining a first correspondence between the absolute thickness of the battery cell at zero pressure and the remaining power of the battery cell, and multiple second correspondences between the absolute thickness of the battery cell at multiple pressures and the remaining power of the battery cell, wherein the pressures correspond one-to-one to the second correspondences.

[0076] The first correspondence can be determined based on multiple remaining capacities of the battery cells and the absolute thickness of the battery cells corresponding to each remaining capacities at zero pressure. The first correspondence can be represented by a curve. The multiple remaining capacities can be 10% SOC, 20% SOC, 50% SOC, 80% SOC, etc., which are not limited here. It should be noted that the absolute thickness of the battery cells corresponding to each remaining capacities at zero pressure can be obtained by measurement or calculation. Figure 2 As shown, the curve corresponding to 0 MPa in the figure is the first corresponding relationship, which includes all SOCs of the battery cells and the absolute thickness of the battery cells corresponding to each SOC under zero pressure.

[0077] There are multiple second corresponding relationships. A certain pressure is applied to the battery cell to obtain the corresponding relationship between the absolute thickness of the battery cell under the pressure and the remaining power of the battery cell. The corresponding relationship is the second corresponding relationship corresponding to the pressure. For example, for any first pressure among multiple pressures, the second corresponding relationship can also be determined based on multiple remaining powers of the battery cell and the absolute thickness of the battery cell corresponding to each remaining power under the first pressure. The second corresponding relationship can also be represented by a curve.

[0078] like Figure 2 As shown, the figure includes multiple curves, among which the curve shown at 0MPa is the first corresponding relationship, and the curves corresponding to 1MPa, 2MPa and 4MPa are the second corresponding relationships of the battery cell under different pressures. Each second corresponding relationship can include the total SOC of the battery cell and the absolute thickness of the battery cell corresponding to each SOC under a certain pressure.

[0079] Step 102: Acquire a first absolute thickness corresponding to a target remaining power from the first corresponding relationship, and acquire a second absolute thickness corresponding to the target remaining power from each of the second corresponding relationships.

[0080] The target remaining power can be selected according to actual conditions and is not limited here. From the first corresponding relationship, the first absolute thickness of the battery cell corresponding to the target remaining power under zero pressure can be obtained.

[0081] Likewise, the second absolute thickness of the battery cell corresponding to the target remaining power under the first pressure can be obtained from the second corresponding relationship.

[0082] Step 103: Obtain the strain of the battery cell under each of the pressures according to the first absolute thickness and a plurality of the second absolute thicknesses.

[0083] For each pressure, the strain of the battery cell under the pressure can be obtained by calculating based on the first absolute thickness and the second absolute thickness corresponding to the pressure.

[0084] Step 104 , obtaining a stress-strain relationship of the battery cell at the target remaining power according to the multiple pressures and the strain at each pressure.

[0085] For each pressure, the stress under the pressure can be calculated. For example, the stress can be obtained by dividing the pressure by the stress-bearing area of ​​the battery cell. According to multiple stresses and the strain corresponding to each stress, the stress-strain relationship is obtained. For example, curve fitting is performed on multiple stresses and the strain corresponding to each stress to obtain the stress-strain relationship of the battery cell at the target remaining power.

[0086] Through the above steps, the stress-strain relationship of the battery cell under the target remaining power can be obtained. Through this relationship, the strain of the battery cell under different stresses can be obtained. The deformation of the battery cell can be obtained according to the strain, and the stress of the battery cell can be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress of the battery cell.

[0087] In one embodiment of the present application, obtaining multiple second corresponding relationships between the absolute thickness of the battery cell under multiple pressures and the remaining power of the battery cell includes:

[0088] When a first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell are acquired, each of the data pairs comprising a remaining power of the battery cell and an absolute thickness of the battery cell under the first pressure, the remaining power in each of the data pairs being different, and the first pressure being any one of the plurality of pressures;

[0089] Data fitting is performed on the plurality of data pairs to obtain a second corresponding relationship corresponding to the first pressure.

[0090] In the above, the battery cells are subjected to charge and discharge tests at different remaining capacities and pressures, and the data pair between the absolute thickness of the battery cells and the remaining capacities of the battery cells is recorded at each pressure.

[0091] For ease of expression, any one of the multiple pressures is referred to as the first pressure. When the first pressure is applied to the battery cell, multiple data pairs obtained during the charging and discharging process of the battery cell are obtained. Each data pair includes a remaining power of the battery cell and the absolute thickness of the battery cell under the first pressure under the remaining power. The remaining power of the battery cell included in each data pair is different.

[0092] Data fitting is performed on multiple data pairs. For example, the remaining power of the battery cell is used as the horizontal coordinate of the rectangular coordinate system, and the absolute thickness under the first pressure is used as the vertical coordinate of the rectangular coordinate system. The points formed by the multiple data pairs on the rectangular coordinate system are fitted to obtain a fitting curve, which is the second corresponding relationship corresponding to the first pressure.

[0093] The above processing is performed for each pressure to obtain the second corresponding relationship corresponding to each pressure.

[0094] In an embodiment of the present application, data fitting can be performed on a limited number of data pairs to obtain a second corresponding relationship corresponding to the first pressure, thereby improving the efficiency of obtaining the second corresponding relationship and facilitating subsequent acquisition of the stress-strain relationship of the battery cell at the target remaining power based on the second corresponding relationship.

[0095] It should be noted that when obtaining the first corresponding relationship, the method of obtaining the second corresponding relationship can also be adopted. For example, when the battery cell is under zero pressure, multiple data pairs obtained during the battery cell charging and discharging process are obtained. Each data pair here includes a remaining power of the battery cell and the absolute thickness of the battery cell under zero pressure at the remaining power. The remaining power of the battery cell included in each data pair is different.

[0096] In another embodiment of the present application, when the first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell are obtained, including:

[0097] Applying a first pressure to the battery cell and leaving it to stand for a preset time;

[0098] The battery cell is charged and discharged to obtain a plurality of data pairs.

[0099] In the above, the preset duration can be set according to actual conditions, for example, the preset duration can be 1 hour or 2 hours, etc., which is not limited here.

[0100] During the charge and discharge process of the battery cell, multiple absolute thicknesses corresponding to multiple different residual capacities of the battery cell can be obtained, and the multiple residual capacities correspond to the multiple absolute thicknesses one by one; multiple data pairs are obtained according to the multiple residual capacities and the multiple absolute thicknesses. One residual capacities and the absolute thickness corresponding to the residual capacities constitute one data pair.

[0101] In the above, after applying the first pressure to the battery cell, the battery cell is left to stand for a preset time, so that the effect of creep on the thickness of the battery cell under the first pressure tends to be stable, thereby making the absolute thickness of the battery cell under the first pressure more accurate.

[0102] In one embodiment of the present application, the battery cell is charged and discharged to obtain a plurality of data pairs, including:

[0103] Performing a first charge and discharge process on the battery cell;

[0104] During the second charge-discharge process of the battery cell, a plurality of absolute thicknesses corresponding to a plurality of different remaining capacities of the battery cell are obtained, wherein the plurality of remaining capacities correspond to the plurality of absolute thicknesses in a one-to-one manner;

[0105] According to the plurality of remaining power and the plurality of absolute thicknesses, a plurality of data pairs are obtained. A remaining power and the absolute thickness corresponding to the remaining power constitute a data pair.

[0106] In an embodiment, the battery cell is subjected to an additional charge and discharge treatment, for example, the battery cell is subjected to two charge and discharge treatments. By adding one charge and discharge treatment, the thickness expansion of the battery cell during the charge and discharge treatment can be stabilized, thereby making the absolute thickness of the battery cell under the first pressure more accurate. Figure 3 The figure shows the thickness expansion curve of the battery cell during the charge and discharge process. In the figure, the battery cell is charged and discharged twice.

[0107] For example, at the beginning of the test, a first pressure is applied to the surface of the battery cell, and the battery cell is left at rest for 2 hours under this pressure. During this period, the battery cell is not charged or discharged, and the battery cell is always at 0% SOC, i.e., fully discharged. After the rest period, the battery cell is charged and discharged for the first time. The specific process may be: after charging to the upper limit voltage of the battery cell at a constant current rate of 0.33C, constant voltage charging is performed at this voltage, and the cutoff condition is that the charging current is less than 0.05C (the upper limit voltage depends on the battery cell design). After standing for 5 minutes, the battery cell is discharged to the lower limit voltage at a rate of 0.33C (the lower limit voltage depends on the battery cell design).

[0108] In the embodiment of the present application, performing the first charge and discharge treatment on the battery cell can stabilize the thickness expansion of the battery cell when performing the second charge and discharge treatment on the battery cell, thereby making the absolute thickness of the battery cell under the first pressure obtained more accurate.

[0109] In another embodiment of the present application, the absolute thickness of the battery cell under the first pressure is the sum of the absolute thickness of the battery cell under zero pressure, the creep thickness and the expansion thickness, wherein the creep thickness is the change in thickness of the battery cell when the first pressure is applied to the battery cell, and the expansion thickness is the expansion of the thickness of the battery cell when the battery cell is charged and discharged.

[0110] In the above, when determining the absolute thickness of the battery cell under the first pressure, the creep thickness and the expansion thickness are added, and the influence of the battery cell creep on the change of the absolute thickness of the battery cell and the influence of the battery cell charging and discharging on the change of the absolute thickness of the battery cell are taken into consideration, which can improve the accuracy of the calculation of the absolute thickness of the battery cell under the first pressure.

[0111] In one embodiment of the present application, obtaining the strain of the battery cell under each of the pressures according to the first absolute thickness and the plurality of the second absolute thicknesses includes:

[0112] Obtaining a difference between a second absolute thickness corresponding to a second pressure and the first absolute thickness, wherein the second pressure is any one of the plurality of pressures;

[0113] The strain of the battery cell under the second pressure is calculated according to the difference and the first absolute thickness.

[0114] In the above, the difference is the first absolute thickness minus the second absolute thickness corresponding to the second pressure, and the difference is a positive number. The difference is divided by the first absolute thickness to obtain the strain of the battery cell under the second pressure.

[0115] By calculating in the above manner, the strain of the battery cell with the target remaining power under multiple pressures can be obtained.

[0116] In this embodiment, the strain of the battery cell under each of the pressures is obtained through the first absolute thickness and the plurality of the second absolute thicknesses, so as to facilitate the subsequent acquisition of the stress-strain relationship.

[0117] In another embodiment of the present application, according to the plurality of pressures and the strain under each pressure, the stress-strain relationship of the battery cell under the target remaining power is obtained, including:

[0118] Obtaining stress corresponding to the third pressure according to a third pressure and a stress-bearing area of ​​the battery cell when the third pressure is applied thereto, wherein the third pressure is any one of the plurality of pressures;

[0119] The stress corresponding to each of the third pressures is used as a first coordinate axis, and the strain corresponding to the third pressure is used as a second coordinate axis to obtain a curve for characterizing the stress-strain relationship of the battery cell under the target remaining power.

[0120] In the above, the third pressure is divided by the force-bearing area to obtain the stress corresponding to the third pressure. Through this calculation method, the stress corresponding to each pressure can be obtained.

[0121] The stress corresponding to each third pressure is used as the first coordinate axis of the rectangular coordinate system, and the strain corresponding to the third pressure is used as the second coordinate axis of the rectangular coordinate system. The stress corresponding to each pressure and the strain corresponding to the pressure are converted into coordinate points in the rectangular coordinate axis, and these multiple coordinate points are fitted to obtain a fitting curve. The fitting curve is the stress-strain relationship curve of the battery cell under the target remaining power. Figure 4 As shown, the curve in the figure is the stress-strain relationship curve of the battery cell at 50% SOC.

[0122] Through the above steps, a curve for characterizing the stress-strain relationship of the battery cell under the target remaining power can be obtained. Through the curve, the strain of the battery cell under different stresses can be obtained, and the deformation of the battery cell can be obtained according to the strain. The stress of the battery cell can also be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress of the battery cell.

[0123] See also Figure 5 , is a schematic diagram of the structure of the device for determining the stress-strain relationship of a battery cell provided in an embodiment of the present application, such as Figure 5 As shown, the battery cell stress-strain relationship determination device 500 includes:

[0124] A first acquisition module 501 is used to acquire a first corresponding relationship between an absolute thickness of a battery cell under zero pressure and a remaining power of the battery cell;

[0125] A second acquisition module 502, for obtaining a plurality of second corresponding relationships between the absolute thickness of the battery cell under a plurality of pressures and the remaining power of the battery cell, wherein the pressures correspond to the second corresponding relationships in a one-to-one manner;

[0126] A third acquisition module 503, configured to acquire a first absolute thickness corresponding to a target remaining power from the first corresponding relationship, and to acquire a second absolute thickness corresponding to the target remaining power from each of the second corresponding relationships;

[0127] A fourth acquisition module 504 is used to obtain the strain of the battery cell under each of the pressures according to the first absolute thickness and the plurality of the second absolute thicknesses;

[0128] The fifth acquisition module 505 is used to obtain the stress-strain relationship of the battery cell at the target remaining power according to the multiple pressures and the strain under each pressure.

[0129] In the embodiment of the present application, the stress-strain relationship of the battery cell under the target remaining power can be obtained. Through this relationship, the strain of the battery cell under different stresses can be obtained. The deformation of the battery cell can be obtained according to the strain, and the stress exerted on the battery cell can also be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress exerted on the battery cell.

[0130] In an embodiment of the present application, the second acquisition module 502 includes:

[0131] a first acquisition submodule, configured to acquire, when a first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell, each of the data pairs comprising a remaining power of the battery cell and an absolute thickness of the battery cell under the first pressure, the remaining power in each of the data pairs being different, and the first pressure being any one of the plurality of pressures;

[0132] The fitting submodule is used to perform data fitting on the plurality of data pairs to obtain a second corresponding relationship corresponding to the first pressure.

[0133] In an embodiment of the present application, data fitting can be performed on a limited number of data pairs to obtain a second corresponding relationship corresponding to the first pressure, thereby improving the efficiency of obtaining the second corresponding relationship and facilitating subsequent acquisition of the stress-strain relationship of the battery cell at the target remaining power based on the second corresponding relationship.

[0134] In an embodiment of the present application, the first acquisition submodule includes:

[0135] A first unit, used for applying a first pressure to the battery cell and leaving it to stand for a preset time;

[0136] The second unit is used to charge and discharge the battery cell to obtain a plurality of data pairs.

[0137] In the embodiment of the present application, after the first pressure is applied to the battery cell, it is left to stand for a preset time so that the effect of creep on the thickness of the battery cell under the first pressure tends to be stable, thereby making the absolute thickness of the battery cell under the first pressure more accurate.

[0138] In one embodiment of the present application, the second unit includes:

[0139] A first subunit, used for performing a first charge and discharge process on the battery cell;

[0140] The second subunit is used to obtain a plurality of absolute thicknesses corresponding to a plurality of different remaining capacities of the battery cell during the second charge and discharge process of the battery cell, wherein the plurality of remaining capacities correspond to the plurality of absolute thicknesses in a one-to-one manner;

[0141] The acquisition subunit is used to obtain a plurality of the data pairs according to the plurality of remaining power and the plurality of absolute thicknesses.

[0142] In the embodiment of the present application, performing the first charge and discharge treatment on the battery cell can stabilize the thickness expansion of the battery cell when performing the second charge and discharge treatment on the battery cell, thereby making the absolute thickness of the battery cell under the first pressure obtained more accurate.

[0143] In one embodiment of the present application, the absolute thickness of the battery cell under the first pressure is the sum of the absolute thickness of the battery cell under zero pressure, the creep thickness and the expansion thickness, wherein the creep thickness is the change in thickness of the battery cell when the first pressure is applied to the battery cell, and the expansion thickness is the expansion of the thickness of the battery cell when the battery cell is charged and discharged.

[0144] In an embodiment of the present application, when determining the absolute thickness of the battery cell under the first pressure, the creep thickness and the expansion thickness are added, and the influence of the battery cell creep on the change of the absolute thickness of the battery cell and the influence of the battery cell charging and discharging on the change of the absolute thickness of the battery cell are taken into consideration, thereby improving the accuracy of the calculation of the absolute thickness of the battery cell under the first pressure.

[0145] In an embodiment of the present application, the fourth acquisition module 504 includes:

[0146] A second acquisition submodule, used to acquire a difference between a second absolute thickness corresponding to a second pressure and the first absolute thickness, wherein the second pressure is any one of the multiple pressures;

[0147] The third acquisition submodule is used to calculate the strain of the battery cell under the second pressure according to the difference and the first absolute thickness.

[0148] In the embodiment of the present application, the strain of the battery cell under each of the pressures is obtained through the first absolute thickness and the plurality of the second absolute thicknesses, so as to facilitate the subsequent acquisition of the stress-strain relationship.

[0149] In an embodiment of the present application, the fifth acquisition module 505 includes:

[0150] a fourth acquisition submodule, configured to obtain a stress corresponding to the third pressure according to a third pressure and a stress-bearing area of ​​the battery cell when the third pressure is applied thereto, wherein the third pressure is any one of the plurality of pressures;

[0151] The fifth acquisition submodule is used to obtain a curve characterizing the stress-strain relationship of the battery cell under the target remaining power, using the stress corresponding to each of the third pressures as the first coordinate axis and the strain corresponding to the third pressure as the second coordinate axis.

[0152] In an embodiment of the present application, a curve can be obtained to characterize the stress-strain relationship of a battery cell under a target remaining power. Through the curve, the strain of the battery cell under different stresses can be obtained, and the deformation of the battery cell can be obtained based on the strain. The stress exerted on the battery cell can also be inferred based on the deformation of the battery cell, thereby realizing the analysis of the deformation and stress exerted on the battery cell.

[0153] In addition, the embodiments of the present application may be implemented by providing a computer storage medium having computer program instructions stored thereon; when the computer program instructions are executed by a processor, any one of the methods for determining the stress-strain relationship of a battery cell in the above embodiments is implemented.

[0154] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0155] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), appropriate firmware, plug-in, function card, etc. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or communication link by a data signal carried in a carrier. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (Radio Frequency, RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0156] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0157] Aspects of the present disclosure are described above with reference to the flowchart and / or block diagram of the method, device, equipment and computer program product according to the embodiment of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for determining stress-strain relationship of a battery cell, characterized in that: include: Acquire a first correspondence between an absolute thickness of a battery cell at zero pressure and a remaining amount of power of the battery cell, and acquire multiple second correspondences between the absolute thickness of the battery cell at multiple pressures and the remaining amount of power of the battery cell, wherein the pressures correspond to the second correspondences one by one; Acquire a first absolute thickness corresponding to a target remaining power from the first corresponding relationship, and acquire a second absolute thickness corresponding to the target remaining power from each of the second corresponding relationships; Obtaining the strain of the battery cell under each of the pressures according to the first absolute thickness and the plurality of the second absolute thicknesses; According to the multiple pressures and the strain under each pressure, the stress-strain relationship of the battery cell under the target remaining power is obtained.

2. The method for determining the stress-strain relationship of a battery cell according to claim 1, characterized in that: Acquiring multiple second corresponding relationships between the absolute thickness of the battery cell under multiple pressures and the remaining power of the battery cell, including: When a first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell are acquired, each of the data pairs comprising a remaining power of the battery cell and an absolute thickness of the battery cell under the first pressure, the remaining power in each of the data pairs being different, and the first pressure being any one of the plurality of pressures; Data fitting is performed on the plurality of data pairs to obtain a second corresponding relationship corresponding to the first pressure.

3. The method for determining the stress-strain relationship of a battery cell according to claim 2, characterized in that: When the first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell are obtained, including: Applying a first pressure to the battery cell and leaving it to stand for a preset time; The battery cell is charged and discharged to obtain a plurality of data pairs.

4. The method for determining the stress-strain relationship of a battery cell according to claim 3, characterized in that: The battery cell is charged and discharged to obtain a plurality of data pairs, including: Performing a first charge and discharge process on the battery cell; During the second charge-discharge process of the battery cell, a plurality of absolute thicknesses corresponding to a plurality of different remaining capacities of the battery cell are obtained, wherein the plurality of remaining capacities correspond to the plurality of absolute thicknesses in a one-to-one manner; A plurality of data pairs are obtained according to the plurality of remaining capacities and the plurality of absolute thicknesses.

5. The method for determining the stress-strain relationship of a battery cell according to claim 2, characterized in that: The absolute thickness of the battery cell under the first pressure is the sum of the absolute thickness of the battery cell under zero pressure, the creep thickness and the expansion thickness, wherein the creep thickness is the thickness change of the battery cell when the first pressure is applied to the battery cell, and the expansion thickness is the thickness expansion of the battery cell when the battery cell is charged and discharged.

6. The method for determining the stress-strain relationship of a battery cell according to any one of claims 1 to 5, characterized in that: Obtaining the strain of the battery cell under each of the pressures according to the first absolute thickness and the plurality of the second absolute thicknesses, comprising: Obtaining a difference between a second absolute thickness corresponding to a second pressure and the first absolute thickness, wherein the second pressure is any one of the plurality of pressures; The strain of the battery cell under the second pressure is calculated according to the difference and the first absolute thickness.

7. The method for determining the stress-strain relationship of a battery cell according to any one of claims 1 to 5, characterized in that: According to the plurality of pressures and the strain under each pressure, the stress-strain relationship of the battery cell under the target remaining power is obtained, including: Obtaining stress corresponding to the third pressure according to a third pressure and a stress-bearing area of ​​the battery cell when the third pressure is applied thereto, wherein the third pressure is any one of the plurality of pressures; The stress corresponding to each of the third pressures is used as a first coordinate axis, and the strain corresponding to the third pressure is used as a second coordinate axis to obtain a curve for characterizing the stress-strain relationship of the battery cell under the target remaining power.

8. A device for determining stress-strain relationship of a battery cell, characterized in that: include: A first acquisition module, used to acquire a first corresponding relationship between an absolute thickness of a battery cell under zero pressure and a remaining power of the battery cell; A second acquisition module, used for obtaining a plurality of second corresponding relationships between the absolute thickness of the battery cell under a plurality of pressures and the remaining power of the battery cell, wherein the pressures correspond to the second corresponding relationships in a one-to-one manner; a third acquisition module, configured to acquire a first absolute thickness corresponding to a target remaining power from the first corresponding relationship, and to acquire a second absolute thickness corresponding to the target remaining power from each of the second corresponding relationships; a fourth acquisition module, configured to obtain the strain of the battery cell under each of the pressures according to the first absolute thickness and a plurality of the second absolute thicknesses; The fifth acquisition module is used to obtain the stress-strain relationship of the battery cell under the target remaining power according to the multiple pressures and the strain under each pressure.

9. The device for determining stress-strain relationship of a battery cell according to claim 8, characterized in that: The second acquisition module includes: a first acquisition submodule, configured to acquire, when a first pressure is applied to the battery cell, a plurality of data pairs obtained during the charge and discharge process of the battery cell, each of the data pairs comprising a remaining power of the battery cell and an absolute thickness of the battery cell under the first pressure, the remaining power in each of the data pairs being different, and the first pressure being any one of the plurality of pressures; The fitting submodule is used to perform data fitting on the plurality of data pairs to obtain a second corresponding relationship corresponding to the first pressure.

10. A readable storage medium, characterized in that: The readable storage medium stores a program or instruction, and when the program or instruction is executed by the processor, the steps of the method for determining the stress-strain relationship of a battery cell as described in any one of claims 1 to 7 are implemented.

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