CN117034720B - Battery pressure evaluation method, device, system and storage medium - Google Patents
Battery pressure evaluation method, device, system and storage medium Download PDFInfo
- Publication number
- CN117034720B CN117034720B CN202311288785.2A CN202311288785A CN117034720B CN 117034720 B CN117034720 B CN 117034720B CN 202311288785 A CN202311288785 A CN 202311288785A CN 117034720 B CN117034720 B CN 117034720B
- Authority
- CN
- China
- Prior art keywords
- battery
- strain
- matrix
- bearing area
- load
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000011156 evaluation Methods 0.000 title claims abstract description 46
- 238000003860 storage Methods 0.000 title claims abstract description 8
- 239000011159 matrix material Substances 0.000 claims abstract description 157
- 238000013507 mapping Methods 0.000 claims abstract description 96
- 238000004088 simulation Methods 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims description 32
- 238000005259 measurement Methods 0.000 claims description 15
- 238000010276 construction Methods 0.000 claims description 9
- 238000009826 distribution Methods 0.000 description 24
- 238000012360 testing method Methods 0.000 description 12
- 238000004364 calculation method Methods 0.000 description 11
- 230000008569 process Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 10
- 239000000463 material Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 239000007943 implant Substances 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/0028—Force sensors associated with force applying means
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Geometry (AREA)
- Evolutionary Computation (AREA)
- General Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Secondary Cells (AREA)
Abstract
The invention discloses a battery pressure evaluation method, a device, a system and a storage medium, wherein the battery pressure evaluation method comprises the following steps: dividing the battery shell into a preset number of bearing areas according to preset rules, establishing a battery simulation model with virtual bearing areas, and setting strain sensors on the bearing areas; constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix; applying preset pressure to the bearing area in the battery simulation model, and solving a mapping matrix according to a first strain value extracted from the model; and (3) changing the internal pressure of the battery, acquiring a second strain value monitored by the strain sensor, solving a strain matrix according to the second strain value and the mapping matrix, and obtaining a load vector according to the mapping matrix and the strain matrix. The technical scheme provided by the invention can solve the technical problems of high cost and high operation difficulty in the prior art when the pressure of the battery is evaluated.
Description
Technical Field
The present invention relates to the field of battery technologies, and in particular, to a method, an apparatus, a system, and a storage medium for evaluating battery pressure.
Background
With the continuous improvement of the market share of new energy automobiles, the demand of power batteries is also continuously increased. In the process of charging and discharging, the battery cell can expand due to the increase of the thickness of the pole piece, the growth of SEI (Solid Electrolyte Interface ) films, gas production and the like, so that the battery cell shell generates constraint force on the pole group. The restraining force of the surface of the pole group can influence the electrochemical performance of the battery to a certain extent, so that the acquisition of the stress distribution state of the surface of the pole group plays an important role in battery design. At present, the stress distribution of the contact part between the surface of the square battery cell electrode group and the shell mainly has two acquisition modes.
Firstly, by means Of simulation, the existing simulation calculation process is to build a complete square cell model comprising an outer shell, a cover plate and a pole group, and as the pole group is Of a multi-layer structure and the mechanical properties Of each component material can be changed along with the progress Of the Charge and discharge process, the mechanical characteristic parameters Of each component material Of the pole group are required to obtain different SOCs (State Of Charge) and different temperatures for simulation calculation, so that the difficulty Of simulation calculation is high, the pole group model is usually simplified to a certain extent, and is partially or completely simplified to an equivalent homogeneous material when being built, and the inherent errors caused by structural homogenization are difficult to eliminate for the simplification and assumption Of the pole group. The method is to build a complete square cell model, simplify and homogenize the electrode group to give a certain expansion characteristic parameter to the electrode group, and finally extract the stress distribution state of the electrode group surface from the simulation result. Because the structure and the material characteristics of the polar group are complex, all or part of the polar group needs to be converted into an equivalent homogeneous structure in the modeling process, and the simplifying mode of the polar group has inherent error of model simplification; and for the battery pole group expansion model, the expansion characteristic parameters of the pole group or each component material need to be input, and the expansion characteristic parameters are closely related to the SOC state of the battery, so that the expansion characteristic parameters are difficult to accurately acquire.
The second is to implant a film sensor in the battery during the manufacturing process, and connect the film sensor with a data converter and a computer, thereby reading the pressure distribution state of the measurement area. The mode has higher requirements on the film sensor, not only needs to cover the whole pole group surface, but also does not influence the electrochemical performance of the battery, and the operation difficulty of the film sensor implantation process is higher, and the short circuit risk exists in the process.
Disclosure of Invention
The invention provides a battery pressure evaluation method, a device, a system and a storage medium, which aim to effectively solve the technical problems of high cost and high operation difficulty in evaluating the battery pressure in the prior art.
According to an aspect of the present invention, there is provided a battery pressure evaluation method including:
dividing the battery shell into a preset number of bearing areas according to preset rules, and establishing a battery simulation model with virtual bearing areas;
constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix;
applying preset pressure to the virtual bearing area in the battery simulation model, and solving the mapping matrix according to a first strain value corresponding to the virtual bearing area;
and changing the internal pressure of the battery, actually measuring to obtain a second strain value corresponding to the bearing area, and solving the load vector according to the second strain value and the mapping matrix.
Further, setting strain sensors on the bearing areas, wherein dividing the battery case into a preset number of bearing areas according to a preset rule comprises:
determining a preset direction for arranging the strain sensor;
uniformly dividing the battery shell into the preset number of bearing areas in the preset direction;
and the strain sensors are equidistantly arranged on the bearing area along the preset direction.
Further, the constructing the stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix comprises:
constructing the stress matrix according to the following formula:
，
wherein,indicate->Strain coefficient on the individual carrier regions +.>Indicate->The load value on the individual load bearing areas,for the total number of carrying areas, +.>Is the mapping matrix.
Further, applying a preset pressure to the virtual bearing area in the battery simulation model, and solving the mapping matrix according to the first strain value corresponding to the virtual bearing area includes:
applying unit uniform load to each virtual bearing area in the battery simulation model in sequence, and solving a single-column mapping matrix of the virtual bearing area through a first strain value corresponding to the virtual bearing area;
and constructing the mapping matrix according to a plurality of single-column mapping matrices corresponding to the plurality of virtual bearing areas.
Further, the battery pressure evaluation method further includes:
setting a first node and a second node in each bearing area along the preset direction, and enabling the node distance between the first node and the second node to be a preset value.
Further, the solving the single-column mapping matrix of the virtual bearing area through the first strain value corresponding to the virtual bearing area includes:
respectively calculating the distance variation generated in the preset direction by the node distance corresponding to each virtual bearing area;
dividing the distance variation by the node distance to obtain first strain values corresponding to a plurality of virtual bearing areas to serve as the single-column mapping matrix.
Further, the preset number is determined according to the following method:
determining the pressure evaluation accuracy of the battery;
determining the sensor precision, the sensor size and the layout difficulty of the strain sensor;
and determining the preset number according to the pressure evaluation precision, the sensor size and the layout difficulty degree.
Optionally, the method further comprises:
before the battery shell is divided into a preset number of bearing units according to a preset rule, a symmetrical model of the battery shell and the cover plate is built according to the battery shell, and symmetrical constraint is carried out on symmetrical interfaces in the symmetrical model.
According to another aspect of the present invention, there is also provided a battery pressure evaluation apparatus including:
the model building module is used for building a battery simulation model with a virtual bearing area;
the matrix construction module is used for constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix;
the first matrix solving module is used for applying preset pressure to the virtual bearing area in the battery simulation model and solving the mapping matrix according to a first strain value corresponding to the virtual bearing area;
and the second matrix construction module is used for solving the load vector according to the second strain value and the mapping matrix.
According to another aspect of the present invention, there is also provided a battery pressure evaluation system including:
the battery pressure evaluation device as described above;
the battery is provided with a battery shell, wherein the battery shell is divided into a preset number of bearing areas according to a preset rule;
the strain sensor is arranged on the bearing area, and is used for acquiring a second strain value corresponding to the bearing area and sending the second strain value to the battery pressure evaluation device after the internal pressure of the battery changes.
According to another aspect of the present invention, there is also provided a storage medium having stored therein a plurality of instructions adapted to be loaded by a processor to perform any of the battery pressure assessment methods as described above.
Through one or more of the above embodiments of the present invention, at least the following technical effects can be achieved:
in the technical scheme disclosed by the invention, a battery shell is divided into a plurality of bearing areas, and a strain sensor is arranged; constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix; applying preset pressure to the bearing area in the battery simulation model, and solving a mapping matrix according to the corresponding first strain value; and (3) changing the internal pressure of the battery, obtaining a second strain value through a strain sensor, solving a strain matrix according to the second strain value and the mapping matrix, and obtaining a load vector according to the mapping matrix and the strain matrix. According to the scheme, the problem of stress distribution of the outer surface of the battery pole group is converted into stress distribution research of the inner surface of the shell, a mapping relation between stress distribution states of the inner side of the shell and the strain state of the outer surface is established, and the stress distribution situation of the inner surface of the shell is reversely deduced through the test result of the strain state of the outer surface of the shell. The method can eliminate inherent errors brought about by simplification of the battery pole group in the calculation process of the simulation method, and directly arrange the stress sensor on the surface of the battery, so that the test process is simpler and more convenient, the cost is lower, the problems of high cost and high operation difficulty of the existing test means are solved, and the measurement precision can be improved.
Drawings
The technical solution and other advantageous effects of the present invention will be made apparent by the following detailed description of the specific embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 is a flowchart illustrating steps of a method for evaluating battery pressure according to an embodiment of the present invention;
FIG. 2 is a schematic view of a cell housing carrying area division and sensor arrangement;
FIG. 3 is a schematic diagram of a strain sensor measurement system;
FIG. 4 is a schematic diagram of node locations in a bearer area;
fig. 5 is a schematic view of a cell pressure distribution state;
FIG. 6 is a finite element model of a battery enclosure and boundary conditions;
FIG. 7 is a schematic diagram of a bearer area division;
FIG. 8 is a schematic diagram of a cell pressure distribution;
fig. 9 is a schematic structural diagram of a battery pressure evaluation device according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a battery pressure evaluation system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that, unless explicitly specified and defined otherwise, the term "and/or" herein is merely an association relationship describing associated objects, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. The character "/" herein generally indicates that the associated object is an "or" relationship unless otherwise specified.
Fig. 1 is a flowchart illustrating steps of a battery pressure evaluation method according to an embodiment of the present invention, where according to an aspect of the present invention, a battery pressure evaluation method is provided, and the battery pressure evaluation method includes:
step 101: dividing the battery shell into a preset number of bearing areas according to preset rules, and establishing a battery simulation model with virtual bearing areas;
step 102: constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix;
step 103: applying preset pressure to the virtual bearing area in the battery simulation model, and solving the mapping matrix according to a first strain value corresponding to the virtual bearing area;
step 104: and changing the internal pressure of the battery, actually measuring to obtain a second strain value corresponding to the bearing area, and solving the load vector according to the second strain value and the mapping matrix.
Because the stress on the outer surface of the battery pole group and the stress on the inner surface of the battery shell are a pair of interaction forces, the problem of stress distribution on the inner surface of the pole group can be converted into the stress distribution research on the outer surface of the shell. The scheme provides a method for acquiring the stress distribution state of a square battery cell electrode group by combining testing and simulation. And establishing a mapping relation between the stress distribution state of the inner side of the shell and the strain state of the outer surface of the shell based on the battery shell simulation model, and reversely pushing out the stress distribution condition of the inner surface of the shell through the test result of the strain state of the outer surface of the shell. The steps 101 to 104 are specifically described below.
In step 101, dividing a battery shell into a preset number of bearing areas according to preset rules, and establishing a battery simulation model with virtual bearing areas;
illustratively, the battery case has a plurality of faces, and the strain sensor may be provided at one or more of the faces selected to have the largest area. Fig. 2 is a schematic diagram of a dividing manner of a bearing area of a battery case and a sensor arrangement, for example, dividing a maximum surface of the battery case into m bearing areas, setting a strain sensor in a geometric center in each bearing area, wherein a bearing area number 1 corresponds to a sensor number 1, and so on, there are m bearing units in total, and setting m strain sensors. Fig. 3 is a schematic diagram of a strain sensor measurement system, wherein data collected by all strain sensors are uploaded to a data collector and then transmitted to a computer for data processing.
After the corresponding bearing area is determined for the real battery shell, a battery simulation model with virtual bearing areas is established according to the battery shell and the bearing areas, wherein the virtual bearing areas in the battery simulation model correspond to the plurality of bearing areas one by one,
in step 102, constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix;
illustratively, the forces inside and outside the battery are a pair of reaction forces, and a mathematical model of the mapping relationship between the stress on the inner surface of the case and the strain on the outer surface can be expressed in a matrix form. When an external force or an internal force is applied to any one of the positions, a certain force is generated corresponding to all other positions. For example, m bearing areas in fig. 2, if an external force or an internal force is applied to any i-th bearing area, a certain acting force is generated by all the remaining m-1 bearing areas.
Therefore, the stress relation between each bearing area and the rest of the bearing areas can be established, and correspondingly, the stress matrix between the rest of the bearing areas and the rest of the bearing areas can be established. Specifically, the matrix is composed of three parts, namely a load vector, a strain matrix and a mapping matrix, wherein the load value in the load vector can be obtained according to actual measurement of the strain sensor, and then the strain matrix and the mapping matrix are calculated according to data obtained through the test.
In step 103, applying a preset pressure to the virtual bearing area in the battery simulation model, and solving the mapping matrix according to a first strain value corresponding to the virtual bearing area;
for example, in order to calculate the mapping matrix, the preset pressure may be determined in advance, and when performing the pressure test simulation on each virtual bearing area, the same unit uniform load is applied. In the stress matrix, there are three variables of a load vector, a strain matrix and a mapping matrix, and if the load value is fixed as a unit number, the load value is converted into a relation between the two variables of the strain matrix and the mapping matrix. Thus, the mapping matrix may be solved according to the first strain values.
In step 104, the internal pressure of the battery is changed, a second strain value corresponding to the bearing area is obtained through actual measurement, and the load vector is solved according to the second strain value and the mapping matrix.
Illustratively, in the stress matrix, there are three variables, namely a load vector, a strain matrix and a mapping matrix, and when the mapping matrix is determined, the relationship between the two variables of the load vector and the strain matrix is converted.
For a real battery shell, after the internal pressure of the battery changes, a load value can be obtained through actual measurement of a strain sensor on the battery shell, then a strain matrix is solved, and finally a load vector is obtained, namely the stress relation of the battery shell is obtained.
Further, setting strain sensors on the bearing areas, wherein dividing the battery case into a preset number of bearing areas according to a preset rule comprises:
determining a preset direction for arranging the strain sensor;
uniformly dividing the battery shell into the preset number of bearing areas in the preset direction;
and the strain sensors are equidistantly arranged on the bearing area along the preset direction.
Illustratively, because some strain sensors have a particular detection direction, a preset direction needs to be determined in advance. Taking fig. 1 as an example, the preset direction is a horizontal direction, strain sensors are arranged at the geometric center position of each bearing area on the outer surface of the battery along the horizontal direction, and the number of the sensors is consistent with that of the bearing areas. The preset direction may be a vertical direction. If the strain sensor is a multi-directional sensor, other directions may be used, and in a specific application, the preset direction may be determined according to the requirement, which is not limited in the present invention.
Further, the constructing the stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix comprises:
constructing the stress matrix according to the following formula:
，
wherein,indicate->Strain coefficient on the individual carrier regions +.>Indicate->The load value on the individual load bearing areas,for the total number of carrying areas, +.>Is the mapping matrix.
Illustratively, the elements in the mapping matrix reflect the mapping relationship between the load on the load bearing region and the structural response at the measurement point. For example, the number of the cells to be processed,is indicated at +.>The unit uniform load on the bearing area is in the +.>Structural strain created at the measurement points of the individual load bearing regions.
Further, applying a preset pressure to the virtual bearing area in the battery simulation model, and solving the mapping matrix according to the first strain value corresponding to the virtual bearing area includes:
applying unit uniform load to each virtual bearing area in the battery simulation model in sequence, and solving a single-column mapping matrix of the virtual bearing area through a first strain value corresponding to the virtual bearing area;
and constructing the mapping matrix according to a plurality of single-column mapping matrices corresponding to the plurality of virtual bearing areas.
By way of example, unit uniform load is applied to each virtual bearing area in turn, and the first strain value at each measuring point is extracted to obtain a complete mapping matrix.
When a unit uniform load is applied to the 1 st virtual bearing area, the load vector matrix can be expressed by the following formula:
，
by bringing the above matrix into the stress matrix, a relational expression between the strain matrix corresponding to the 1 st virtual bearing area and the single-column mapping matrix can be obtained, and the 1 st column single-column mapping matrix is shown as follows:
，
and obtaining the specific value of the first column in the mapping matrix according to the above formula. And so on, for the ith virtual bearing area, if the unit uniform load is applied and the first strain value at each other measuring point is extracted, the load vector matrix can be represented by the following formula:
，
by bringing the above matrix into the stress matrix, a relational expression between the strain matrix corresponding to the ith virtual bearing area and the single-column mapping matrix can be obtained, and the ith single-column mapping matrix is shown in the following formula:
，
and applying unit uniform load to each virtual bearing area to obtain a single-column mapping matrix of each column in the mapping matrix, and constructing a complete mapping matrix according to a plurality of single-column mapping matrices corresponding to all the virtual bearing areas.
Further, the battery pressure evaluation method further includes:
setting a first node and a second node in each bearing area along the preset direction, and enabling the node distance between the first node and the second node to be a preset value.
Illustratively, fig. 4 is a schematic view of node positions in the bearing areas, dividing the battery case into m bearing areas, taking two nodes in each bearing area, and the positions of the first node and the second node correspond to the measurement interval of the strain sensor. Node1 and node2 shown in fig. 4 are two nodes selected in the first bearer region. The node distance of node1 and node2 along the preset direction is denoted as a.
Further, the solving the single-column mapping matrix of the virtual bearing area through the first strain value corresponding to the virtual bearing area includes:
respectively calculating the distance variation generated in the preset direction by the node distance corresponding to each virtual bearing area;
dividing the distance variation by the node distance to obtain first strain values corresponding to a plurality of virtual bearing areas to serve as the single-column mapping matrix.
By way of example, applying a unit uniform load, for example a uniform force of 1MPa, in a first virtual load-bearing zone, extracting respectively first strain values of two nodes in each virtual load-bearing zone along a preset direction, for example denoted b1, b2 … bn, then，/>，/>. Further, a relation between a specific strain matrix and a single-column mapping matrix is obtained, and the strain coefficient is +.>The following formula is taken in:
，
and applying 1MPa uniform distribution force in each other virtual bearing area according to the same method, and analogizing to finally obtain the complete mapping matrix K.
And changing the internal pressure of the battery, actually measuring to obtain a second strain value corresponding to the bearing area, and solving the load vector according to the second strain value and the mapping matrix.
For example, there are various conditions that may cause changes in the internal pressure of the battery, such as temperature changes, external atmospheric pressure changes, battery charge and discharge, etc. For example, the battery is charged to a specific SOC state at a certain rate, and the strain sensor reading is recorded in the SOC state.
Abbreviated stress matrix asIn the known mapping matrix->And Strain matrix->In the case of (2) the load vector->The mapping matrix can be used for direct inversion calculation: />。
Wherein the load vectorAnd f1 in the first bearing area is uniformly distributed with the pressure of f1 (MPa), and so on, so that the stress distribution state of the large surface of the whole battery cell is obtained. FIG. 5 is a schematic view showing the distribution of cell pressure, wherein the values in each carrying region represent the pressureSize in Mpa.
Further, the preset number is determined according to the following method:
determining the pressure evaluation accuracy of the battery;
determining the sensor precision, the sensor size and the layout difficulty of the strain sensor;
and determining the preset number according to the pressure evaluation precision, the sensor size and the layout difficulty degree.
For example, when strain sensors are arranged in the carrying areas, the number of sensors corresponds to the number of carrying areas. The number of the bearing areas is determined by the surface pressure distribution precision required to be measured and the difficulty degree of pasting the strain sensors, and is determined specifically according to the pressure evaluation precision, the sensor size and the layout difficulty degree. The more the number of the bearer area divisions is, the more accurate the measurement result is, but the larger the data processing amount is, so that the measurement result needs to be determined according to specific application requirements.
Optionally, the method further comprises:
before the battery shell is divided into a preset number of bearing units according to a preset rule, a symmetrical model of the battery shell and the cover plate is built according to the battery shell, and symmetrical constraint is carried out on symmetrical interfaces in the symmetrical model.
Illustratively, the mapping matrixThe calibration of the sensor is obtained by respectively applying unit uniform load in each bearing area and extracting the strain of all sensors under each working condition. Because the loading process of unit uniform load is difficult to realize by a test means, the calibration of the mapping matrix is obtained by a simulation means.
Firstly, a symmetrical model of a battery cell shell and a cover plate is established, and symmetrical constraint is made on a symmetrical interface, wherein the battery cell shell finite element model and boundary conditions are shown in fig. 6, the battery cell cover plate model is only used as an illustration, cover plate parts are omitted during modeling, if higher calculation precision is pursued, a complete cover plate model can be established, and the symmetrical constraint is used for reducing the number of grids and improving the calculation efficiency, and whether the symmetrical constraint is made does not affect the calculation result.
How the cell electrode group surface pressure of the battery is evaluated according to the method in the present embodiment is described below according to example one.
Example 1
Fig. 7 is a schematic diagram of dividing a bearing area, dividing a battery shell into 9 bearing areas in a finite element model, selecting two nodes corresponding to two ends of a strain sensor pasting position in each bearing area, and marking 18 nodes in total, wherein the node distance is 8 mm. And correspondingly establishing a battery simulation model according to the data of the real battery shell.
In the battery simulation model, uniform surface pressure of 1MPa is applied to a first virtual bearing area, distances of two marking nodes in the same virtual bearing area along a preset direction are respectively extracted, a strain coefficient of each measuring point after uniform load is applied to the first virtual bearing area, the distance between two points obtained through simulation is divided by the initial distance between the two points by 8mm, a first strain value at a corresponding strain sensor pasting position is obtained, and simulation results are shown in table 1.
TABLE 1 Strain coefficient at each measurement point after applying unit Uniform load to first virtual load bearing region
And taking the calculated strain coefficient as a first column of the mapping matrix K.
Then, unit uniform load is applied in the residual virtual bearing area in sequence in the same way, the strain value of each measuring point under each uniform load working condition is extracted, the corresponding strain coefficient is calculated, and finally a complete mapping matrix K shown as follows is formed:
，
then, a strain response test is performed, for example, the real battery is charged to 100% soc at 1C rate, and a second strain value is obtained through a strain sensor on the real battery case. A second strain value read by the strain sensor in this SOC state is recorded, for example, the strain readings of each strain sensor are shown in table 2 below:
TABLE 2 actual measured second strain values
Finally, the surface pressure distribution calculation is carried out, fig. 8 is a schematic diagram of the battery pressure distribution, and the load vector is obtained through calculationThe following is shown:
，
through one or more of the above embodiments of the present invention, at least the following technical effects can be achieved:
in the technical scheme disclosed by the invention, a battery shell is divided into a plurality of bearing areas, and a strain sensor is arranged; constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix; applying preset pressure to the bearing area in the battery simulation model, and solving a mapping matrix according to the corresponding first strain value; and (3) changing the internal pressure of the battery, obtaining a second strain value through a strain sensor, solving a strain matrix according to the second strain value and the mapping matrix, and obtaining a load vector according to the mapping matrix and the strain matrix. According to the scheme, the problem of stress distribution of the outer surface of the battery pole group is converted into stress distribution research of the inner surface of the shell, a mapping relation between stress distribution states of the inner side of the shell and the strain state of the outer surface is established, and the stress distribution situation of the inner surface of the shell is reversely deduced through the test result of the strain state of the outer surface of the shell. The method can eliminate inherent errors brought about by simplification of the battery pole group in the calculation process of the simulation method, and directly arrange the stress sensor on the surface of the battery, so that the test process is simpler and more convenient, the cost is lower, the problems of high cost and high operation difficulty of the existing test means are solved, and the measurement precision can be improved.
Based on the same inventive concept as a battery pressure evaluation method according to an embodiment of the present invention, an embodiment of the present invention provides a battery pressure evaluation device, referring to fig. 9, including:
a model building module 201, configured to build a battery simulation model with a virtual bearing area;
the matrix construction module 202 is configured to construct a stress matrix of the stress relationship of the battery case according to the load vector, the strain matrix and the mapping matrix;
a first matrix solving module 203, configured to apply a preset pressure to the virtual bearing area in the battery simulation model, and solve the mapping matrix according to a first strain value corresponding to the virtual bearing area;
a second matrix construction module 204 for solving the load vector based on the second strain values and the mapping matrix.
Further, the matrix construction module 202 is further configured to:
constructing the stress matrix according to the following formula:
，
wherein,indicate->Strain coefficient on the individual carrier regions +.>Indicate->The load value on the individual load bearing areas,for the total number of carrying areas, +.>Is the mapping matrix.
Further, the first matrix solving module 203 is further configured to:
applying unit uniform load to each virtual bearing area in the battery simulation model in sequence, and solving a single-column mapping matrix of the virtual bearing area through a first strain value corresponding to the virtual bearing area;
and constructing the mapping matrix according to a plurality of single-column mapping matrices corresponding to the plurality of virtual bearing areas.
Further, the first matrix solving module 203 is further configured to:
respectively calculating the distance variation generated in the preset direction by the node distance corresponding to each virtual bearing area;
dividing the distance variation by the node distance to obtain first strain values corresponding to a plurality of virtual bearing areas to serve as the single-column mapping matrix.
Other aspects and implementation details of the battery pressure evaluation device are the same as or similar to those of the battery pressure evaluation method described above, and are not described herein.
Based on the same inventive concept as a battery pressure evaluation method according to an embodiment of the present invention, an embodiment of the present invention provides a battery pressure evaluation system, referring to fig. 10, the system includes:
the battery pressure evaluation device 301 as described above;
a battery 302 having a battery case, wherein the battery case is divided into a preset number of carrying areas according to a preset rule;
the strain sensor 303 is disposed on the load-bearing area, and is configured to obtain a second strain value corresponding to the load-bearing area when the internal pressure of the battery changes, and send the second strain value to the battery pressure evaluation device.
Other aspects and implementation details of the battery pressure evaluation system are the same as or similar to those of the battery pressure evaluation method described above, and are not described herein.
According to another aspect of the present invention, there is also provided a storage medium having stored therein a plurality of instructions adapted to be loaded by a processor to perform any of the battery pressure assessment methods as described above.
In summary, although the present invention has been described in terms of the preferred embodiments, the preferred embodiments are not limited to the above embodiments, and various modifications and changes can be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention is defined by the appended claims.
Claims (10)
1. A battery pressure evaluation method, characterized in that the battery pressure evaluation method comprises:
dividing the battery shell into a preset number of bearing areas according to preset rules, and establishing a battery simulation model with virtual bearing areas;
constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix;
applying preset pressure to the virtual bearing area in the battery simulation model, and solving the mapping matrix according to a first strain value corresponding to the virtual bearing area;
the internal pressure of the battery is changed, a second strain value corresponding to the bearing area is obtained through actual measurement, and the load vector is solved according to the second strain value and the mapping matrix;
the construction of the stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix comprises the following steps:
constructing the stress matrix according to the following formula:
，
wherein,indicate->Strain coefficient on the individual carrier regions +.>Indicate->Load value on the individual load areas, +.>For the total number of carrying areas, +.>For the mapping matrix +.>Indicate->The unit uniform load on the bearing area is in the +.>Strain values generated on the individual load bearing areas.
2. The battery pressure evaluation method according to claim 1, wherein a strain sensor is provided on the load-bearing region, and the dividing the battery case into a preset number of load-bearing regions according to a preset rule comprises:
determining a preset direction for arranging the strain sensor;
uniformly dividing the battery shell into the preset number of bearing areas in the preset direction;
and the strain sensors are equidistantly arranged on the bearing area along the preset direction.
3. The method for evaluating the battery pressure according to claim 2, wherein applying a preset pressure to the virtual bearing area in the battery simulation model, and solving the mapping matrix according to the first strain value corresponding to the virtual bearing area comprises:
applying unit uniform load to each virtual bearing area in the battery simulation model in sequence, and solving a single-column mapping matrix of the virtual bearing area through a first strain value corresponding to the virtual bearing area;
and constructing the mapping matrix according to a plurality of single-column mapping matrices corresponding to the plurality of virtual bearing areas.
4. The battery pressure evaluation method according to claim 3, characterized in that the battery pressure evaluation method further comprises:
setting a first node and a second node in each bearing area along the preset direction, and enabling the node distance between the first node and the second node to be a preset value.
5. The battery pressure assessment method according to claim 4, wherein said solving the single-column mapping matrix of the virtual load-bearing area by the first strain value corresponding to the virtual load-bearing area comprises:
respectively calculating the distance variation generated in the preset direction by the node distance corresponding to each virtual bearing area;
dividing the distance variation by the node distance to obtain first strain values corresponding to a plurality of virtual bearing areas to serve as the single-column mapping matrix.
6. The battery pressure evaluation method according to claim 2, wherein the preset number is determined according to the following method:
determining the pressure evaluation accuracy of the battery;
determining the sensor precision, the sensor size and the layout difficulty of the strain sensor;
and determining the preset number according to the pressure evaluation precision, the sensor size and the layout difficulty degree.
7. The battery pressure evaluation method according to claim 6, wherein the method further comprises:
before the battery shell is divided into a preset number of bearing units according to a preset rule, a symmetrical model of the battery shell and the cover plate is built according to the battery shell, and symmetrical constraint is carried out on symmetrical interfaces in the symmetrical model.
8. A battery pressure evaluation apparatus for implementing the battery pressure evaluation method according to any one of claims 1 to 7, characterized in that the apparatus comprises:
the model building module is used for building a battery simulation model with a virtual bearing area;
the matrix construction module is used for constructing a stress matrix of the stress relation of the battery shell according to the load vector, the strain matrix and the mapping matrix;
the first matrix solving module is used for applying preset pressure to the virtual bearing area in the battery simulation model and solving the mapping matrix according to a first strain value corresponding to the virtual bearing area;
the second matrix construction module is used for solving the load vector according to a second strain value and the mapping matrix;
wherein the matrix construction module is further configured to:
constructing the stress matrix according to the following formula:
，
wherein,indicate->Strain coefficient on the individual carrier regions +.>Indicate->Load value on the individual load areas, +.>For the total number of carrying areas, +.>For the mapping matrix +.>Indicate->The unit uniform load on the bearing area is in the +.>Strain values generated on the individual load bearing areas.
9. A battery pressure evaluation system, the system comprising:
the battery pressure evaluation device according to claim 8;
the battery is provided with a battery shell, wherein the battery shell is divided into a preset number of bearing areas according to a preset rule;
the strain sensor is arranged on the bearing area, and is used for acquiring a second strain value corresponding to the bearing area and sending the second strain value to the battery pressure evaluation device after the internal pressure of the battery changes.
10. A storage medium having stored therein a plurality of instructions adapted to be loaded by a processor to perform the battery pressure assessment method of any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311288785.2A CN117034720B (en) | 2023-10-08 | 2023-10-08 | Battery pressure evaluation method, device, system and storage medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311288785.2A CN117034720B (en) | 2023-10-08 | 2023-10-08 | Battery pressure evaluation method, device, system and storage medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117034720A CN117034720A (en) | 2023-11-10 |
| CN117034720B true CN117034720B (en) | 2024-01-23 |
Family
ID=88632154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311288785.2A Active CN117034720B (en) | 2023-10-08 | 2023-10-08 | Battery pressure evaluation method, device, system and storage medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117034720B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108520133A (en) * | 2018-03-30 | 2018-09-11 | 江铃控股有限公司 | Automobile storage battery installing bracket strength analysis method |
| CN115425312A (en) * | 2022-09-23 | 2022-12-02 | 重庆储安科技创新中心有限公司 | Battery module and expansion monitoring method thereof |
| CN116337608A (en) * | 2021-12-23 | 2023-06-27 | 荣盛盟固利新能源科技股份有限公司 | Battery expansion distribution force monitoring system and method |
| CN116454440A (en) * | 2023-04-28 | 2023-07-18 | 蜂巢能源科技(无锡)有限公司 | Battery module expansion force prediction method, device, equipment and storage medium |
-
2023
- 2023-10-08 CN CN202311288785.2A patent/CN117034720B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108520133A (en) * | 2018-03-30 | 2018-09-11 | 江铃控股有限公司 | Automobile storage battery installing bracket strength analysis method |
| CN116337608A (en) * | 2021-12-23 | 2023-06-27 | 荣盛盟固利新能源科技股份有限公司 | Battery expansion distribution force monitoring system and method |
| CN115425312A (en) * | 2022-09-23 | 2022-12-02 | 重庆储安科技创新中心有限公司 | Battery module and expansion monitoring method thereof |
| CN116454440A (en) * | 2023-04-28 | 2023-07-18 | 蜂巢能源科技(无锡)有限公司 | Battery module expansion force prediction method, device, equipment and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117034720A (en) | 2023-11-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113420471B (en) | Power lithium battery thermal model construction and establishment method and system based on electrochemical mechanism | |
| Yang et al. | An improved semi-empirical model for thermal analysis of lithium-ion batteries | |
| CN108627766B (en) | Real-time measurement method for internal temperature of battery core in battery module and battery pack | |
| Panchal et al. | Measurement of temperature gradient (dT/dy) and temperature response (dT/dt) of a prismatic lithium-ion pouch cell with LiFePO 4 cathode material | |
| CN109884527A (en) | A kind of lithium ion battery thermal runaway quantity of heat production calculation method | |
| Jiang et al. | A stack pressure based equivalent mechanical model of lithium-ion pouch batteries | |
| Liu et al. | Review of thermal coupled battery models and parameter identification for lithium-ion battery heat generation in EV battery thermal management system | |
| CN112034368A (en) | Battery capacity calibration method and device | |
| CN114924193A (en) | Battery safety assessment method | |
| CN115158076A (en) | Metering error evaluation method, device and computer readable storage medium | |
| Xu et al. | An electrochemical-thermal coupling model for prismatic lithium-ion batteries over wide temperature range | |
| Zhong et al. | In-situ characterizations and mechanism analysis of mechanical inhomogeneity in a prismatic battery module | |
| Chen et al. | Mechanism of inhomogeneous deformation and equal-stiffness design of large-format prismatic lithium-ion batteries | |
| CN117034720B (en) | Battery pressure evaluation method, device, system and storage medium | |
| CN113139304A (en) | Method and device for calculating expansion force of battery module and control equipment | |
| Wang et al. | State of health estimation of lithium-ion battery in wide temperature range via temperature-aging coupling mechanism analysis | |
| Hong et al. | An improved thermal single particle model and parameter estimation for high-capacity battery cell | |
| Kumar et al. | Lithium-ion ferrous phosphate prismatic cell aging analysis and assessment for the development of battery management systems | |
| CN113835031B (en) | Information processing method, apparatus, electronic device and storage medium | |
| CN116699445A (en) | Capacity prediction method and system for battery energy storage system | |
| Zhou et al. | Battery state of health monitoring by estimation of side reaction current density via retrospective-cost subsystem identification | |
| Yang et al. | Temperature field evolution of cylindrical battery: In-situ visualizing experiments and high fidelity internal morphology simulations | |
| CN110826206A (en) | Nondestructive soft measurement method and system for three-dimensional temperature inside battery | |
| CN109633475A (en) | A kind of LiFePO4 energy-type cells life prediction method | |
| CN115856670A (en) | Method and device for calculating calorific value of battery, battery and vehicle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |