CN113139304A - Method and device for calculating expansion force of battery module and control equipment - Google Patents
Method and device for calculating expansion force of battery module and control equipment Download PDFInfo
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Abstract
The invention provides a method and a device for calculating the expansion force of a battery module and control equipment, wherein the calculation method comprises the following steps: acquiring the expansion force of a single battery cell in the tested battery module during cyclic charge and discharge at a preset temperature; establishing a mathematical model between the charge-discharge cycle times of the battery cell and the expansion force according to the expansion force; calculating the equivalent thermal expansion coefficient of the battery cell according to the mathematical model and the battery cell parameters of the battery cell; and (3) obtaining the battery module expansion force of the tested battery module through simulation calculation by utilizing the modeling model of the tested battery module according to the electric core parameters and the equivalent thermal expansion coefficient. Above-mentioned scheme only needs to carry out the bulging force data test after the charge-discharge cycle of less number of times to single electric core, alright calculate the bulging force of battery module under N times charge-discharge cycle to can save electric core quantity, test cost and test cycle. This scheme can satisfy the calculation of the battery module bulging force of the battery module of the different series-parallel mode of arranging of homogeneous electric core.
Description
Technical Field
The invention relates to the field of batteries, in particular to a method and a device for calculating expansion force of a battery module and control equipment.
Background
Generally, the cell thickness of the battery varies during the charging and discharging processes. The thickness can be gradually increased along with the increase of the charging and discharging times, and the expansion can not be completely pressed back when the battery is pressed, so that the battery core generates a bulging phenomenon.
If the battery module design is improper, the module end plate can be propped up badly at the bulging force that the battery module produced in long-term use, destroys the module structure, leads to the safety risk. Therefore, the calculation of the expansion force needs to be considered in the design and development of the module, the expansion force test of the traditional battery module is only carried out after the module is processed and is carried out by using test equipment, so that the expansion force test of the battery module usually needs a long period and is high in cost, and the development of a simulation calculation method of the expansion force of the battery module is imperative.
Disclosure of Invention
The embodiment of the invention provides a method and a device for calculating the expansion force of a battery module and control equipment, which are used for solving the problems of long test period and high cost of the expansion force of the battery module in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme:
according to an aspect of the present invention, there is provided a method for calculating an expansion force of a battery module, including:
acquiring the expansion force of a single battery cell in the tested battery module during cyclic charge and discharge at a preset temperature;
establishing a mathematical model between the charge-discharge cycle times of the battery cell and the expansion force according to the expansion force;
calculating the equivalent thermal expansion coefficient of the battery cell according to the mathematical model and the battery cell parameters of the battery cell;
and obtaining the battery module expansion force of the tested battery module through simulation calculation according to the electric core parameters and the equivalent thermal expansion coefficient by utilizing the modeling model of the tested battery module.
Optionally, obtaining an expansion force of a single battery cell in the battery module to be tested during cyclic charge and discharge at a preset temperature includes:
carrying out cyclic charge and discharge on the battery cell at a preset temperature, and carrying out expansion force test on the battery cell by using a battery cell expansion force test device;
the maximum value of the expansion force was recorded for each charge-discharge cycle.
Optionally, establishing a mathematical model between the number of charge and discharge cycles of the battery cell and the expansion force according to the expansion force includes:
drawing a relation curve between the number of charge-discharge cycles and the maximum value of the expansion force corresponding to each charge cycle;
and fitting a mathematical model between the charge-discharge cycle times and the expansion force according to the relation curve.
Optionally, the cell parameters include equivalent elastic modulus, poisson's ratio, and density.
Optionally, the calculation method further includes:
and calculating the mass and the volume of the battery cell to obtain the density.
Optionally, the calculation method further includes:
testing the natural frequency of the battery cell to obtain an experimental frequency value;
and obtaining the equivalent elastic modulus of the battery cell according to the experimental frequency value, the density and a preset Poisson ratio.
Optionally, calculating an equivalent thermal expansion coefficient of the battery cell according to the mathematical model and a battery cell parameter of the battery cell, including:
obtaining a first expansion force corresponding to the preset charging and discharging times through the mathematical model;
and carrying out simulation calculation by utilizing a modeling model of the battery cell expansion force testing device according to the battery cell parameters of the battery cell and the first expansion force to obtain the equivalent thermal expansion coefficient of the battery cell.
According to another aspect of the present invention, there is provided a device for calculating an expansion force of a battery module, including:
the circulation test module is used for acquiring the expansion force of a single battery cell in the tested battery module when the single battery cell is subjected to circulation charging and discharging at a preset temperature;
the model establishing module is used for establishing a mathematical model between the charge-discharge cycle times of the battery cell and the expansion force according to the expansion force;
the first calculation module is used for calculating the equivalent thermal expansion coefficient of the battery cell according to the mathematical model and the battery cell parameters of the battery cell;
and the second calculation module is used for obtaining the battery module expansion force of the tested battery module through simulation calculation according to the electric core parameters and the equivalent thermal expansion coefficient by utilizing the modeling model of the tested battery module.
Optionally, the cycle testing module comprises:
the test unit is used for carrying out cyclic charge and discharge on the battery cell at a preset temperature and carrying out expansion force test on the battery cell by using the battery cell expansion force test device;
and the recording unit is used for recording the maximum value of the expansion force in each charge-discharge cycle.
Optionally, the model building module includes:
the drawing unit is used for drawing a relation curve between the number of charging and discharging cycles and the maximum value of the expansion force corresponding to each charging cycle;
and the fitting unit is used for fitting a mathematical model between the charge and discharge cycle times and the expansion force according to the relation curve.
Optionally, the cell parameters include equivalent elastic modulus, poisson's ratio, and density.
Optionally, the first computing module comprises:
and the density calculation unit is used for calculating the density according to the mass and the volume of the battery core.
Optionally, the first computing module comprises:
the frequency testing unit is used for testing the natural frequency of the battery cell to obtain an experimental frequency value;
and the result calculation unit is used for obtaining the equivalent elastic modulus of the battery cell according to the experimental frequency value, the density and a preset Poisson ratio.
Optionally, the first computing module comprises:
the data acquisition unit is used for acquiring a first expansion force corresponding to the preset charging and discharging times through the mathematical model;
and the simulation calculation unit is used for performing simulation calculation by using a modeling model of the cell expansion force testing device and according to the cell parameters of the cell and the first expansion force to obtain the equivalent thermal expansion coefficient of the cell.
According to another aspect of the present invention, there is provided a control apparatus comprising a memory, a processor, and a program stored on the memory and executable on the processor; the processor, when executing the program, implements the computing method as described above.
The invention has the beneficial effects that:
above-mentioned scheme only needs to carry out the bulging force data test after the charge-discharge cycle of less number of times to single electric core, alright calculate the bulging force of battery module under N times charge-discharge cycle to can save electric core quantity, test cost and test cycle. This scheme can satisfy the calculation of the battery module bulging force of the battery module of the different series-parallel mode of arranging of homogeneous electric core, and maneuverability is better. In addition, the scheme combines the experiment and the simulation, parameters of the experiment test are used for simulation calculation, and the precision of the simulation result is high.
Drawings
Fig. 1 is a schematic diagram illustrating a method for calculating an expansion force of a battery module according to an embodiment of the invention;
fig. 2 is a schematic diagram illustrating a device for calculating an expansion force of a battery module according to an embodiment of the invention;
fig. 3 is a schematic diagram illustrating a result of testing a natural frequency of a cell through a frequency sweep experiment according to an embodiment of the present invention;
fig. 4 shows a cell expansion force testing apparatus provided in an embodiment of the present invention;
fig. 5 shows a relationship curve between the number of battery cell charge-discharge cycles and the expansion force according to an embodiment of the present invention.
Description of reference numerals:
1-electric core; 2-a force sensor; 21-cycle test module; 22-a model building module; 23-a first calculation module; 24-a second calculation module.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
The invention provides a method and a device for calculating the expansion force of a battery module and control equipment, aiming at the problems of long test period and high cost of the expansion force of the battery module in the prior art.
As shown in fig. 1, an embodiment of the invention provides a method for calculating an expansion force of a battery module, including:
s11: the expansion force of a single battery cell 1 in the tested battery module during circulating charge and discharge at the preset temperature is obtained.
Before calculating the expansion force of the battery module, the expansion force condition of a single battery cell 1 in the cyclic charge and discharge process at a certain temperature needs to be obtained.
Optionally, obtain the bulging force of single electric core 1 when carrying out circulation charge-discharge under the temperature of predetermineeing among the battery module of being surveyed, include:
carrying out cyclic charge and discharge on the battery cell 1 at a preset temperature, and carrying out an expansion force test on the battery cell 1 by using a battery cell expansion force test device;
the maximum value of the expansion force was recorded for each charge-discharge cycle.
Specifically, as shown in fig. 4, a schematic diagram of a cell expansion force testing apparatus is shown. The battery core 1 is charged and discharged according to the charging and discharging multiplying power, the stress condition in the battery expansion process can be collected through the force sensor 2, namely the maximum value of the expansion force in the charging and discharging process is counted after each charging and discharging cycle.
S12: establishing a mathematical model between the charge-discharge cycle times of the battery cell 1 and the expansion force according to the expansion force;
optionally, establishing a mathematical model between the number of charge and discharge cycles of the battery cell 1 and the expansion force according to the expansion force includes:
drawing a relation curve between the number of charge-discharge cycles and the maximum value of the expansion force corresponding to each charge cycle;
and fitting a mathematical model between the charge-discharge cycle times and the expansion force according to the relation curve.
Specifically, a relationship curve of the cycle number and the expansion force is drawn, and a mathematical model of the cycle number and the expansion force is fitted according to the relationship curve, as shown in fig. 5. The purpose is to estimate the expansion force of the battery cell 1 after different charging and discharging through less charging and discharging cycle data.
S13: and calculating the equivalent thermal expansion coefficient of the battery cell 1 according to the mathematical model and the battery cell parameters of the battery cell 1.
It should be noted that the expansion force of the battery module in the embodiment of the present invention adopts a finite element simulation calculation principle, and the expansion of the module is simulated and calculated by adopting a principle of expansion with heat and contraction with cold, that is, the actual expansion process of the battery core 1 is simulated by the expansion with heat of the battery core 1 during the finite element analysis. Therefore, the equivalent thermal expansion coefficient of the battery cell 1 needs to be determined before the battery module expansion force simulation is performed.
Optionally, the cell parameters include equivalent elastic modulus, poisson's ratio, and density.
Optionally, the density is calculated by: the density is obtained by calculating the mass and the volume of the battery cell 1. Specifically, the density can be calculated directly by mass/volume.
Optionally, the method for calculating the equivalent elastic modulus includes:
testing the natural frequency of the battery cell 1 to obtain an experimental frequency value;
and obtaining the equivalent elastic modulus of the battery cell 1 according to the experimental frequency value, the density and a preset Poisson ratio.
It should be noted that, since the interior of the battery cell 1 mainly includes the positive electrode material, the negative electrode material, the diaphragm, the electrolyte, and the like, and the structure is complex, the elastic modulus of the battery cell 1 is difficult to directly detect and obtain, and the "equivalent elastic modulus" is required to perform the correlation calculation.
Specifically, the equivalent elastic modulus can be calibrated by a frequency method, and the detailed method is as follows:
according to one embodiment of the present invention, the frequency sweep experiment is performed on the battery cell 1 to test the natural frequency of the battery cell 1, and the frequency sweep experiment result is as shown in fig. 3, where the obtained experimental frequency value includes three peak values respectively representing a first-order frequency 1600hz, a second-order frequency 2176.88hz, and a third-order frequency 2787.13 hz.
Computer Aided Engineering (CAE) modal simulation calculation is carried out on the battery cell 1, the Poisson ratio is set to be 0.4, the battery cell modal simulation calculation result is consistent with the experimental frequency value as much as possible by continuously adjusting the input value of the elastic modulus of the battery cell 1, and the elastic modulus is the equivalent elastic modulus of the battery cell 1 even if the difference value between the battery cell simulation calculation result and the experimental frequency value is smaller than a certain value. If the simulated first-order frequency is 1608hz, and the experimental frequency value is 1600hz, the elastic modulus used for calculation is the equivalent elastic modulus of the battery cell 1.
It should be further noted that, in the embodiment of the present invention, a fixed value of 0.4 is used as the poisson ratio, and generally, a correlation calculation may also be performed by using 0.3 or some other reasonable value according to the situation.
Optionally, calculating an equivalent thermal expansion coefficient of the battery cell 1 according to the mathematical model and the battery cell parameter of the battery cell 1, including:
obtaining a first expansion force corresponding to the preset charging and discharging times through the mathematical model;
and carrying out simulation calculation by utilizing a modeling model of the battery cell expansion force testing device according to the battery cell parameters of the battery cell 1 and the first expansion force to obtain the equivalent thermal expansion coefficient of the battery cell 1.
Specifically, finite element modeling is performed on the battery cell expansion force testing device, a modeling model of the tested battery module is utilized, simulation calculation is performed according to battery cell parameters of the battery cell 1, and by adjusting the thermal expansion coefficient of the battery cell 1, the contact reaction force between the battery cell 1 and a tool in the battery cell expansion force testing device is equal to the first expansion force, and then the first thermal expansion coefficient is the corresponding equivalent thermal expansion coefficient of the battery cell 1 when the battery cell 1 is subjected to the expansion force simulation of charging and discharging for the preset charging and discharging times.
According to one embodiment of the present invention, a method for testing and simulating the equivalent expansion coefficient of the battery cell 1 at a preset temperature is described by calculating the expansion force of the battery module after 800 cycles. The swelling force of 3014N can be deduced from the curve of fig. 5 after 800 cycles of the cell 1. Finite element modeling is carried out on the battery cell expansion force testing device shown in the figure 4, and simulation calculation is carried out by utilizing a modeling model of the battery cell expansion force testing device, wherein the elastic modulus, the Poisson ratio and the density of the battery cell 1 are input by adopting the data obtained above. The thermal expansion coefficient of the battery cell 1 is adjusted to enable the contact reaction force of the battery cell 1 and the tool to reach 3014N, and then the thermal expansion coefficient is the equivalent thermal expansion coefficient when the battery cell 1 is charged and discharged for 800 times of expansion force simulation.
S14: and obtaining the battery module expansion force of the tested battery module through simulation calculation according to the electric core parameters and the equivalent thermal expansion coefficient by utilizing the modeling model of the tested battery module.
It should be noted that, when carrying out finite element modeling to the battery module, thermal-insulated pad, module end plate and the curb plate between electric core, the electric core all need detailed modeling, and the pretightning force that the assembly process module end plate was applyed for electric core 1 also needs to be considered. The elastic modulus, poisson's ratio, density and equivalent thermal expansion coefficient of the battery cell 1 are input by using the data obtained above.
And calculating to obtain the stress conditions of the battery module components to be tested, such as the battery core 1, the module end plate and the like, namely the battery module expansion force of the battery module to be tested. According to the stress condition, whether the structural strength of the battery module meets the requirement after the preset number of charge-discharge cycles can be evaluated, and the evaluation result can be used for structural design and optimization of the battery module.
In the embodiment of the invention, the expansion force of the battery module under N times of charge-discharge cycles can be calculated only by carrying out expansion force data test after a few times of charge-discharge cycles on a single battery cell, so that the number of the battery cells, the test cost and the test period can be saved. This scheme can satisfy the calculation of the battery module bulging force of the battery module of the different series-parallel mode of arranging of homogeneous electric core, and maneuverability is better. In addition, the scheme combines the experiment and the simulation, parameters of the experiment test are used for simulation calculation, and the precision of the simulation result is high.
As shown in fig. 2, an embodiment of the present invention further provides a device for calculating an expansion force of a battery module, including:
and the circulation test module 21 is used for acquiring the expansion force of a single battery cell 1 in the tested battery module during circulation charging and discharging at a preset temperature.
Before calculating the expansion force of the battery module, the expansion force condition of a single battery cell 1 in the cyclic charge and discharge process at a certain temperature needs to be obtained.
Optionally, the cycle testing module 21 includes:
the testing unit is used for performing cyclic charge and discharge on the battery cell 1 at a preset temperature and performing an expansion force test on the battery cell 1 by using a battery cell expansion force testing device;
and the recording unit is used for recording the maximum value of the expansion force in each charge-discharge cycle.
Specifically, as shown in fig. 4, a schematic diagram of a cell expansion force testing apparatus is shown. The battery core 1 is charged and discharged according to the charging and discharging multiplying power, the stress condition in the battery expansion process can be collected through the force sensor 2, namely the maximum value of the expansion force in the charging and discharging process is counted after each charging and discharging cycle.
The model establishing module 22 is configured to establish a mathematical model between the charge and discharge cycle number of the battery cell 1 and the expansion force according to the expansion force;
optionally, the model building module 22 includes:
the drawing unit is used for drawing a relation curve between the number of charging and discharging cycles and the maximum value of the expansion force corresponding to each charging cycle;
and the fitting unit is used for fitting a mathematical model between the charge and discharge cycle times and the expansion force according to the relation curve.
Specifically, a relationship curve of the cycle number and the expansion force is drawn, and a mathematical model of the cycle number and the expansion force is fitted according to the relationship curve, as shown in fig. 5. The purpose is to estimate the expansion force of the battery cell 1 after different charging and discharging through less charging and discharging cycle data.
The first calculating module 23 is configured to calculate an equivalent thermal expansion coefficient of the battery cell 1 according to the mathematical model and the battery cell parameter of the battery cell 1.
It should be noted that the expansion force of the battery module in the embodiment of the present invention adopts a finite element simulation calculation principle, and the expansion of the module is simulated and calculated by adopting a principle of expansion with heat and contraction with cold, that is, the actual expansion process of the battery core 1 is simulated by the expansion with heat of the battery core 1 during the finite element analysis. Therefore, the equivalent thermal expansion coefficient of the battery cell 1 needs to be determined before the battery module expansion force simulation is performed.
Optionally, the cell parameters include equivalent elastic modulus, poisson's ratio, and density.
Optionally, the first calculating module 23 includes:
and the density calculation unit is used for calculating the density according to the mass and the volume of the battery cell 1.
Specifically, the density can be calculated directly by mass/volume.
The frequency testing unit is used for testing the natural frequency of the battery cell 1 to obtain an experimental frequency value;
and the result calculation unit is used for obtaining the equivalent elastic modulus of the battery cell 1 according to the experimental frequency value, the density and a preset Poisson ratio.
It should be noted that, since the interior of the battery cell 1 mainly includes the positive electrode material, the negative electrode material, the diaphragm, the electrolyte, and the like, and the structure is complex, the elastic modulus of the battery cell 1 is difficult to directly detect and obtain, and the "equivalent elastic modulus" is required to perform the correlation calculation.
Specifically, the equivalent elastic modulus can be calibrated by a frequency method, and the detailed method is as follows:
according to one embodiment of the present invention, the frequency sweep experiment is performed on the battery cell 1 to test the natural frequency of the battery cell 1, and the frequency sweep experiment result is as shown in fig. 3, where the obtained experimental frequency value includes three peak values respectively representing a first-order frequency 1600hz, a second-order frequency 2176.88hz, and a third-order frequency 2787.13 hz.
Computer Aided Engineering (CAE) modal simulation calculation is carried out on the battery cell 1, the Poisson ratio is set to be 0.4, the battery cell modal simulation calculation result is consistent with the experimental frequency value as much as possible by continuously adjusting the input value of the elastic modulus of the battery cell 1, and the elastic modulus is the equivalent elastic modulus of the battery cell 1 even if the difference value between the battery cell simulation calculation result and the experimental frequency value is smaller than a certain value. If the simulated first-order frequency is 1608hz, and the experimental frequency value is 1600hz, the elastic modulus used for calculation is the equivalent elastic modulus of the battery cell 1.
It should be further noted that, in the embodiment of the present invention, a fixed value of 0.4 is used as the poisson ratio, and generally, a correlation calculation may also be performed by using 0.3 or some other reasonable value according to the situation.
Optionally, the first calculating module 23 further includes:
the data acquisition unit is used for acquiring a first expansion force corresponding to the preset charging and discharging times through the mathematical model;
and the simulation calculation unit is used for performing simulation calculation by using a modeling model of the cell expansion force testing device and according to the cell parameters of the cell 1 and the first expansion force to obtain the equivalent thermal expansion coefficient of the cell 1.
Specifically, finite element modeling is performed on the battery cell expansion force testing device, a modeling model of the tested battery module is utilized, simulation calculation is performed according to battery cell parameters of the battery cell 1, and by adjusting the thermal expansion coefficient of the battery cell 1, the contact reaction force between the battery cell 1 and a tool in the battery cell expansion force testing device is equal to the first expansion force, and then the first thermal expansion coefficient is the corresponding equivalent thermal expansion coefficient of the battery cell 1 when the battery cell 1 is subjected to the expansion force simulation of charging and discharging for the preset charging and discharging times.
According to one embodiment of the present invention, a method for testing and simulating the equivalent expansion coefficient of the battery cell 1 at a preset temperature is described by calculating the expansion force of the battery module after 800 cycles. The swelling force of 3014N can be deduced from the curve of fig. 5 after 800 cycles of the cell 1. Finite element modeling is carried out on the battery cell expansion force testing device shown in the figure 4, and simulation calculation is carried out by utilizing a modeling model of the battery cell expansion force testing device, wherein the elastic modulus, the Poisson ratio and the density of the battery cell 1 are input by adopting the data obtained above. The thermal expansion coefficient of the battery cell 1 is adjusted to enable the contact reaction force of the battery cell 1 and the tool to reach 3014N, and then the thermal expansion coefficient is the equivalent thermal expansion coefficient when the battery cell 1 is charged and discharged for 800 times of expansion force simulation.
And the second calculation module 24 is configured to obtain a battery module expansion force of the battery module to be tested through simulation calculation according to the electric core parameter and the equivalent thermal expansion coefficient by using the modeling model of the battery module to be tested.
It should be noted that, when carrying out finite element modeling to the battery module, thermal-insulated pad, module end plate and the curb plate between electric core, the electric core all need detailed modeling, and the pretightning force that the assembly process module end plate was applyed for electric core 1 also needs to be considered. The elastic modulus, poisson's ratio, density and equivalent thermal expansion coefficient of the battery cell 1 are input by using the data obtained above.
And calculating to obtain the stress conditions of the battery module components to be tested, such as the battery core 1, the module end plate and the like, namely the battery module expansion force of the battery module to be tested. According to the stress condition, whether the structural strength of the battery module meets the requirement after the preset number of charge-discharge cycles can be evaluated, and the evaluation result can be used for structural design and optimization of the battery module.
In the embodiment of the invention, the expansion force of the battery module under N times of charge-discharge cycles can be calculated only by carrying out expansion force data test after a few times of charge-discharge cycles on a single battery cell, so that the number of the battery cells, the test cost and the test period can be saved. This scheme can satisfy the calculation of the battery module bulging force of the battery module of the different series-parallel mode of arranging of homogeneous electric core, and maneuverability is better. In addition, the scheme combines the experiment and the simulation, parameters of the experiment test are used for simulation calculation, and the precision of the simulation result is high.
The embodiment of the invention also provides control equipment, which comprises a memory, a processor and a program which is stored on the memory and can be operated on the processor; the processor, when executing the program, implements the computing method as described above.
While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
Claims (15)
1. A method for calculating the expansion force of a battery module is characterized by comprising the following steps:
acquiring the expansion force of a single battery cell in the tested battery module during cyclic charge and discharge at a preset temperature;
establishing a mathematical model between the charge-discharge cycle times of the battery cell and the expansion force according to the expansion force;
calculating the equivalent thermal expansion coefficient of the battery cell according to the mathematical model and the battery cell parameters of the battery cell;
and obtaining the battery module expansion force of the tested battery module through simulation calculation according to the electric core parameters and the equivalent thermal expansion coefficient by utilizing the modeling model of the tested battery module.
2. The calculation method of claim 1, wherein obtaining the expansion force of a single battery cell in the battery module to be tested during cyclic charge and discharge at a preset temperature comprises:
carrying out cyclic charge and discharge on the battery cell at a preset temperature, and carrying out expansion force test on the battery cell by using a battery cell expansion force test device;
the maximum value of the expansion force was recorded for each charge-discharge cycle.
3. The calculation method of claim 2, wherein establishing a mathematical model between the number of charge-discharge cycles of the battery cell and the expansion force according to the expansion force comprises:
drawing a relation curve between the number of charge-discharge cycles and the maximum value of the expansion force corresponding to each charge cycle;
and fitting a mathematical model between the charge-discharge cycle times and the expansion force according to the relation curve.
4. The computing method according to claim 1,
the cell parameters include equivalent elastic modulus, poisson's ratio and density.
5. The computing method of claim 4, further comprising:
and calculating the mass and the volume of the battery cell to obtain the density.
6. The computing method of claim 4, further comprising:
testing the natural frequency of the battery cell to obtain an experimental frequency value;
and obtaining the equivalent elastic modulus of the battery cell according to the experimental frequency value, the density and a preset Poisson ratio.
7. The calculation method of claim 3, wherein calculating the equivalent thermal expansion coefficient of the cell according to the mathematical model and the cell parameters of the cell comprises:
obtaining a first expansion force corresponding to the preset charging and discharging times through the mathematical model;
and carrying out simulation calculation by utilizing a modeling model of the battery cell expansion force testing device according to the battery cell parameters of the battery cell and the first expansion force to obtain the equivalent thermal expansion coefficient of the battery cell.
8. A battery module expansive force calculation device is characterized by comprising:
the circulation test module is used for acquiring the expansion force of a single battery cell in the tested battery module when the single battery cell is subjected to circulation charging and discharging at a preset temperature;
the model establishing module is used for establishing a mathematical model between the charge-discharge cycle times of the battery cell and the expansion force according to the expansion force;
the first calculation module is used for calculating the equivalent thermal expansion coefficient of the battery cell according to the mathematical model and the battery cell parameters of the battery cell;
and the second calculation module is used for obtaining the battery module expansion force of the tested battery module through simulation calculation according to the electric core parameters and the equivalent thermal expansion coefficient by utilizing the modeling model of the tested battery module.
9. The computing device of claim 8, wherein the loop test module comprises:
the test unit is used for carrying out cyclic charge and discharge on the battery cell at a preset temperature and carrying out expansion force test on the battery cell by using the battery cell expansion force test device;
and the recording unit is used for recording the maximum value of the expansion force in each charge-discharge cycle.
10. The computing device of claim 9, wherein the model building module comprises:
the drawing unit is used for drawing a relation curve between the number of charging and discharging cycles and the maximum value of the expansion force corresponding to each charging cycle;
and the fitting unit is used for fitting a mathematical model between the charge and discharge cycle times and the expansion force according to the relation curve.
11. The computing device of claim 8,
the cell parameters include equivalent elastic modulus, poisson's ratio and density.
12. The computing device of claim 11, wherein the first computing module comprises:
and the density calculation unit is used for calculating the density according to the mass and the volume of the battery core.
13. The computing device of claim 11, wherein the first computing module comprises:
the frequency testing unit is used for testing the natural frequency of the battery cell to obtain an experimental frequency value;
and the result calculation unit is used for obtaining the equivalent elastic modulus of the battery cell according to the experimental frequency value, the density and a preset Poisson ratio.
14. The computing device of claim 10, wherein the first computing module comprises:
the data acquisition unit is used for acquiring a first expansion force corresponding to the preset charging and discharging times through the mathematical model;
and the simulation calculation unit is used for performing simulation calculation by using a modeling model of the cell expansion force testing device and according to the cell parameters of the cell and the first expansion force to obtain the equivalent thermal expansion coefficient of the cell.
15. A control device comprising a memory, a processor, and a program stored on the memory and executable on the processor; characterized in that the processor implements the calculation method according to any one of claims 1 to 7 when executing the program.
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| CN202010051168.0A Pending CN113139304A (en) | 2020-01-17 | 2020-01-17 | Method and device for calculating expansion force of battery module and control equipment |
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| CN113725505A (en) * | 2021-08-03 | 2021-11-30 | 天津市捷威动力工业有限公司 | Module expansion safety assessment method |
| CN117949836A (en) * | 2024-03-26 | 2024-04-30 | 大秦数字能源技术股份有限公司 | Method, device, terminal and storage medium for identifying hidden danger of thermal runaway of battery |
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