CN116861735A - Method, device, terminal and storage medium for defining expansion parameters of internal structure of battery cell - Google Patents
Method, device, terminal and storage medium for defining expansion parameters of internal structure of battery cell Download PDFInfo
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Abstract
The application relates to a method, a device, a terminal and a storage medium for defining expansion parameters of an internal structure of a battery cell. Comprising the following steps: 1. simplifying definition of the battery cell and defining a local coordinate system of the battery cell; the battery cell comprises a battery cell shell and a battery cell internal structure; 2. testing the expansion deformation of the battery cell in a free state; 3. testing the expansion force of the battery cell under different expansion gaps; 4. calculating the relationship between the expansion deformation and the expansion force of the battery cell; 5. simulating to obtain deformation load relation data of the battery cell shell under the battery cell expansion working condition; 6. calculating to obtain stress-strain relation data of the internal homogenization structure X direction of the battery cell; 7. and determining the internal homogenization structure complete expansion parameter of the cell. The application can truly reflect the change of the internal structural rigidity at each stage of the expansion of the battery cell and provide important support for the improvement of the simulation precision of the expansion of the battery cell.
Description
Technical Field
The application belongs to the technical field of automobiles, and particularly relates to a method, a device, a terminal and a storage medium for defining expansion parameters of an internal structure of a battery cell.
Background
The lithium ion battery is widely applied to new energy automobiles due to the characteristics of high energy density, good power and the like. The lithium ion battery can be accompanied with the problem of expansion in the use process, and the expansion is generated because on one hand, the SEI film is formed in the formation process, gas is generated, the internal air pressure is increased, and the SEI film thickness is increased along with the circulation; on the other hand, during charge and discharge, lithium ions are separated from and intercalated into the layered material to cause the thickness direction change of the pole piece. Battery swelling not only has a significant impact on battery cycle life, but also concerns reliability and safety. In product development, the battery expansion working condition strength performance is obtained by two means: firstly, a physical test is carried out, but the method has long period and high cost, and can be carried out only when a physical test exists; secondly, the method has short period and low cost, and does not need a physical object. At present, the cell expansion simulation method is immature, and the definition of the expansion parameters of the internal structure of the cell becomes a key link for restricting the maturation of the expansion simulation technology.
Disclosure of Invention
In order to solve the problems, the application provides a method, a device, a terminal and a storage medium for defining the internal structural expansion parameters of a new energy battery cell, which can truly reflect the change of the internal structural rigidity at each stage of the expansion of the battery cell and provide important support for improving the simulation precision of the expansion of the battery cell.
The technical scheme of the application is as follows in combination with the accompanying drawings:
in a first aspect, an embodiment of the present application provides a method for defining an expansion parameter of an internal structure of a battery cell, including:
step one, simplifying definition of a battery cell and defining a local coordinate system of the battery cell; the battery cell comprises a battery cell shell and a battery cell internal structure;
step two, testing the expansion deformation of the free state battery cell;
step three, testing the expansion force of the battery cell under different expansion gaps;
calculating the relationship between the expansion deformation and the expansion force of the battery cell;
step five, simulating to obtain deformation load relation data of the battery cell shell under the battery cell expansion working condition;
step six, calculating to obtain stress-strain relation data of the internal homogenization structure X direction of the battery cell;
and step seven, determining the complete expansion parameters of the internal homogenization structure of the battery cell.
Further, the specific method of the first step is as follows:
11 Simplifying the battery cell shell into a hollow cuboid structure, wherein the cuboid size is determined according to the size of the battery cell shell; the internal structure of the battery cell is simplified into a homogenized cuboid structure;
12 Defining a local coordinate system of the battery cell; the center of the battery cell is an origin, the X axis is the thickness direction of the battery cell, the Z axis is vertical upwards, and the Y axis accords with the right-hand spiral rule; defining the X-direction dimension of the battery cell as the thickness of the battery cell, the Y-direction dimension as the width of the battery cell and the Z-direction dimension as the height of the battery cell; defining two vertical surfaces of the battery cell and the X axis as large surfaces of the battery cell, wherein the two vertical surfaces of the battery cell and the Z axis are respectively upper and lower surfaces, and the two vertical surfaces of the battery cell and the Y axis are side surfaces; half of the thickness of the overall structure of the battery cell is recorded as L 1 Half of the thickness of the internal homogenization structure of the battery cell is marked as L 2 The method comprises the steps of carrying out a first treatment on the surface of the Electric coreThe width dimension of the body structure is denoted as w 1 The width dimension of the internal homogenization structure of the battery cell is marked as W 2 The method comprises the steps of carrying out a first treatment on the surface of the The height dimension of the overall structure of the battery cell is recorded as H 1 The height dimension of the internal homogenization structure of the battery cell is marked as H 2 The method comprises the steps of carrying out a first treatment on the surface of the The large area of the overall structure of the battery cell is marked as S 1 The large area of the homogenizing structure in the cell is marked as S 2 。
Further, the specific method of the second step is as follows:
and the battery core is in a free state, and a full life cycle charge-discharge cycle test is carried out on the battery core, so that the relationship data of the expansion deformation and the cycle times of the whole structure of the battery core are obtained.
Further, the specific method of the third step is as follows:
testing to obtain the charge-discharge expansion force data of the battery cell at different gaps according to L 1 Percentages are defined.
Further, the specific method of the fourth step is as follows:
summarizing and drawing each gap and expansion force to obtain the relationship between each expansion gap and expansion force of the battery cell; and obtaining the relation between the deformation amount of the battery cell and the expansion force according to the relation between the equivalent deformation of the battery cell in the X direction and the clearance.
Further, the specific method of the fifth step is as follows:
51 A 1/2 shell is obtained by cutting through an X-axis section passing through the origin of coordinates; simplifying the geometry of the battery cell shell to obtain a simplified structure of the cuboid thin-wall battery cell shell;
52 The geometry of the large surface of the battery cell shell is cut by utilizing the contour of the internal homogenization structure of the battery cell, so that a projection area of the internal homogenization structure on the large surface of the battery cell shell is obtained;
53 Performing finite element meshing;
54 Defining parameters of the cell shell material according to elastic materials, wherein the parameters comprise elastic modulus E and Poisson ratio mu;
55 Constraint and load definition; creating a distributed coupling unit: the independent nodes of the coupling units are unit nodes on the symmetrical cross section of the battery cell shell, and the subordinate nodes are defined as free nodes in the center of the symmetrical cross section; constraining the slave nodes; uniformly distributing load on grids in a projection area of an internal homogenization structure of a large surface of the battery cell;
56 Simulation analysis is carried out on the model; and defining the support reaction force of the shell as the product of the uniformly distributed pressure and the loading area, wherein the deformation of the shell is the deformation of the maximum node of the large-surface deformation of the cell shell, and obtaining the relation between the support reaction force of the cell shell in the X direction and the maximum deformation of the cell shell.
Further, the specific method in the sixth step is as follows:
61 Linear fitting is carried out on the relation between the counter force of the cell shell in the X direction obtained by simulation and the maximum deformation of the cell shell, and a fitting curve R is required 2 ≥0.99；
62 Calculating the relation between the expansion force and the deformation of the internal structure of the battery cell;
the internal expansion force of the battery cell is recorded as f in Integral expansion force f of cell total Reaction force f of cell shell out The relation of (2) is:
f total ＝f in -f out (2)
the cell internal expansion force is calculated by the following formula:
f in ＝f total +f out (3)
thereby obtaining the relationship between the expansion force and the deformation of the internal structure of the battery cell;
63 Acquiring stress-strain relation of the homogenized structure in the cell in the X direction;
assuming uniform deformation of the internal structure in the X direction, the cross-sectional area S of the homogenized structure 2 The X-direction stress σ is calculated by the following formula:
the X-direction strain epsilon is calculated by the following formula:
based on the above, the stress-strain relationship of the internal homogenization structure of the battery cell is obtained.
Further, the specific method of the step seven is as follows:
the homogenized material is defined according to isotropic material, namely, the stress-strain relation in the X direction of the homogenized structure inside the cell is used as the material parameter in all directions.
In a second aspect, an embodiment of the present application further provides a device for defining an expansion parameter of an internal structure of a battery cell, including:
the simplifying module is used for simplifying and defining the battery cell and defining a local coordinate system of the battery cell;
the first testing module is used for testing the expansion deformation of the battery cell in a free state;
the second testing module is used for testing the expansion force of the battery cell in different expansion gaps;
the first calculation module is used for calculating the relationship between the expansion deformation and the expansion force of the battery cell;
the simulation module is used for obtaining deformation load relation data of the battery cell shell under the battery cell expansion working condition in a simulation mode;
the second calculation module is used for calculating and obtaining stress-strain relation data in the X direction of the internal homogenization structure of the battery cell;
and the determining module is used for determining the internal homogenization structure complete expansion parameter of the battery cell.
In a third aspect, a terminal is provided, including:
one or more processors;
a memory for storing the one or more processor-executable instructions;
wherein the one or more processors are configured to:
the method according to the first aspect of the embodiment of the application is performed.
In a fourth aspect, a non-transitory computer readable storage medium is provided, which when executed by a processor of a terminal, enables the terminal to perform the method according to the first aspect of the embodiments of the application.
In a fifth aspect, an application product is provided, which when running at a terminal causes the terminal to perform the method according to the first aspect of the embodiments of the application.
The beneficial effects of the application are as follows:
1) The application develops the expansion deformation of the battery cell in the free state; according to the charge-discharge expansion characteristics of the square shell battery cell, a plurality of expansion gaps are determined, and further the expansion force of the battery cell under different gaps is obtained through testing; the free expansion deformation of the battery core is combined, so that the expansion force of the battery core under the equivalent deformation is obtained;
2) The application establishes a finite element model of the cell shell, and simulates and obtains the relation between the supporting reaction force of the cell shell in the expansion direction of the cell and the deformation;
3) The application combines the deformation-expansion force of the battery cell, the deformation-support reaction of the battery cell shell and the expansion deformation characteristic of the battery cell to obtain the deformation-expansion force relation data of the internal structure of the battery cell, and further combines the size data of the homogenized structure of the internal structure of the battery cell to obtain the stress-strain relation data of the internal structure of the battery cell
4) The application identifies the approximate elastic section and the plastic section according to the stress-strain curve characteristics, further combines the parameter keywords of the elastic plastic material to define the internal structure expansion parameters of the battery cell, and can truly reflect the change of the internal structure rigidity at each stage of the expansion of the battery cell, thereby further providing important support for the improvement of the expansion simulation precision of the battery cell.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for defining expansion parameters of an internal structure of a battery cell according to the present application;
FIG. 2 is a simplified structure of a cell and a schematic diagram of a local coordinate system;
FIG. 3 is a schematic diagram of a single-sided deformation of a cell in a free state;
FIG. 4 is a schematic diagram showing the variation of the cell expansion force with the number of charge and discharge times under a certain gap;
FIG. 5 is a plot of cell expansion test gap rate versus expansion force;
FIG. 6 is a schematic diagram of cell deformation versus expansion force;
FIG. 7 is a schematic diagram of a cell housing grid;
FIG. 8 is a schematic illustration of cell housing constraints and loading;
FIG. 9 is a schematic diagram of the relationship between the deformation and the support reaction of the cell housing obtained by simulation;
FIG. 10 is a schematic diagram of a fitted curve;
FIG. 11 is a schematic diagram showing the relationship between the deformation of the internal structure of the cell and the expansion force;
FIG. 12 is a schematic view of stress-strain curves of the cell internal homogenization structure in the expansion direction;
FIG. 13 is a schematic diagram of an apparatus for defining expansion parameters of an internal structure of a battery cell according to the present application;
fig. 14 is a schematic block diagram of a terminal structure.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance.
Example 1
Fig. 1 is a flowchart of a method for defining an expansion parameter of an internal structure of a battery cell according to an embodiment of the present application, where the method may be performed by an apparatus for defining an expansion parameter of an internal structure of a battery cell according to an embodiment of the present application, and the apparatus may be implemented in software and/or hardware.
The embodiment describes a method for defining the expansion parameters of the internal structure of a battery cell based on a square-shell battery cell with the thickness of 28mm, and specifically comprises the following steps:
step one, simplifying definition of a battery cell and defining a local coordinate system of the battery cell; the battery cell comprises a battery cell shell and a battery cell internal structure;
11 Here, the cell state is a new cell, and soc=0.
When the cell expansion simulation analysis is carried out, the cell shell can be simplified into a hollow cuboid, and the size of the cuboid is determined according to the size of the cell shell; the internal structure may be simplified to a homogenized cuboid structure.
12 Cell local coordinate system definition: the center of the battery cell is the origin, the X axis is the thickness direction of the battery cell, the Z axis is vertical upwards, and the Y axis accords with the right-hand spiral rule. The X-direction dimension of the battery cell is defined as the thickness of the battery cell, the Y-direction dimension is defined as the width of the battery cell, and the Z-direction dimension is defined as the height of the battery cell. Two vertical surfaces of the battery cell and the X axis are defined as large surfaces of the battery cell, two vertical surfaces of the battery cell and the Z axis are respectively upper and lower surfaces, and two vertical surfaces of the battery cell and the Y axis are side surfaces, so that an opinion figure 2 is shown. The thickness of the large surface of the battery cell shell is 0.6mm.
Half of the thickness of the overall structure of the battery cell is recorded as L 1 Half of the thickness of the internal homogenization structure of the battery cell is marked as L 2 The method comprises the steps of carrying out a first treatment on the surface of the The width dimension of the whole structure of the battery cell is recorded as W 1 The width dimension of the internal homogenization structure of the battery cell is marked as W 2 The method comprises the steps of carrying out a first treatment on the surface of the The height dimension of the overall structure of the battery cell is recorded as H 1 The height dimension of the internal homogenization structure of the battery cell is marked as H 2 The method comprises the steps of carrying out a first treatment on the surface of the The large area of the overall structure of the battery cell is marked as S 1 The large area of the homogenizing structure in the cell is marked as S 2 。
Step two, testing the expansion deformation of the free state battery cell;
and the battery core is in a free state, and a full life cycle charge-discharge cycle test is carried out on the battery core, so that the relationship data of the expansion deformation and the cycle times of the whole structure of the battery core are obtained. The free deformation of the single side of the whole structure of the battery cell in the X direction is recorded as delta L 1 Deformation ratio (Δl 1 /L 1 ) Denoted as delta L 1 The number of charge-discharge cycles of the battery core is recorded as N, and the service life of the charge-discharge cycles is recorded as N total . Cell free state charge-discharge unilateral expansion deformation is shown in figure 3, delta L 1 Is 1.8mm.
Step three, testing the expansion force of the battery cell under different expansion gaps;
testing to obtain the charge-discharge expansion force data of the battery cell at different gaps according to L 1 The percentage is defined, and the gap amount is selected to be 0.015L 1 ，0.025*L 1 ，0.035*L 1 ，0.05*L 1 The cell is quite deformed relative to free expansion deformation by: ΔL 1 -0.015*L 1 ，ΔL 1 -0.025*L 1 ，ΔL 1 -0.035*L 1 ，ΔL 1 -0.05*L 1 。
The relationship between the cell expansion force and the charge-discharge cycle number at a certain gap is shown in fig. 4. The expansion force is the counter force of the cell and is marked as f total 。
Calculating the relationship between the expansion deformation and the expansion force of the battery cell;
sum each gap to corresponding N total The expansion forces are summarized and plotted to obtain the relationship between each expansion gap and the expansion force of the battery cell, and the schematic diagram is shown in fig. 5. Further, according to the relation between the equivalent deformation of the cell in the X direction and the clearance, the relation between the cell deformation and the expansion force can be obtained, and the schematic diagram is shown in fig. 6.
Step five, simulating to obtain deformation load relation data of the battery cell shell under the battery cell expansion working condition; and establishing a simulation model of the battery cell shell, and obtaining the relation between the deformation and the support reaction of the battery cell shell through simulation analysis. The method comprises the following steps:
51 A 1/2 shell is obtained by cutting through an X-axis section passing through the origin of coordinates; simplifying the geometry of the battery cell shell to obtain a simplified structure of the cuboid thin-wall battery cell shell;
52 The geometry of the large surface of the battery cell shell is cut by utilizing the contour of the internal homogenization structure of the battery cell, so that a projection area of the internal homogenization structure on the large surface of the battery cell shell is obtained;
53 Performing finite element mesh division to obtain a mesh model shown in fig. 7;
54 Defining parameters of the cell shell material according to elastic materials, wherein the parameters comprise elastic modulus E and Poisson ratio mu;
55 Constraints and load definitions. Creating a distributed coupling unit: the independent node (independent nodes) of the coupling unit is a unit node on the symmetrical section of the battery cell shell, and the subordinate node is defined as a free node in the center of the symmetrical section. Constraining the slave nodes; the uniform load is applied to the grid in the projection area of the internal homogenization structure of the large surface of the cell, and the schematic view is shown in fig. 8.
56 Simulation analysis is carried out on the model. The support reaction force of the shell is defined as the product of the uniformly distributed pressure and the loading area, the deformation of the shell is the deformation of the maximum node of the large-surface deformation of the cell shell, and the relationship between the support reaction force of the cell shell in the X direction and the maximum deformation of the cell shell is obtained, and is schematically shown in fig. 9.
Step six, calculating to obtain stress-strain relation data of the internal homogenization structure X direction of the battery cell;
61 Linear fitting to fig. 9, fitting curves showing opinion fig. 10, the formula can be obtained as follows:
f out ＝1216.2x-32.952 (1)
wherein f out For the counter force of the cell shell, x is the deformation of the cell shell, and the fitting curve R is formed 2 ＝0.9971。
To ensure fitting accuracy, R is required 2 ≥0.99。
62 Calculating the relation between the expansion force and the deformation of the internal structure of the battery cell
The internal expansion force of the battery cell is recorded as f in . Cell overall expansion force f total Reaction force f of cell shell out The relation of (2) is:
f total ＝f in -f out (2)
the cell internal expansion force can be calculated by:
f in ＝f total +f out (3)
further, by combining the data of fig. 6 and the formula (1), the relationship between the expansion force and the deformation amount of the internal structure of the cell can be calculated and obtained, as shown in fig. 11.
63 Acquiring stress-strain relation of the internal homogenization structure X direction of the battery cell;
assuming uniform deformation of the internal structure in the X direction, the cross-sectional area S of the homogenized structure 2 The X-direction stress σ can be calculated by the following formula:
the X-direction strain epsilon can be calculated by the following formula:
for the cell, the cross-sectional area S of the homogenizing structure 2 25000mm 2 ，L 2 The stress strain relationship of the internal homogenization structure of the battery cell can be obtained by combining the data of fig. 10, the formula (4) and the formula (5) with 13.4mm, and the stress strain relationship is schematically shown in fig. 12.
And step seven, determining the complete expansion parameters of the internal homogenization structure of the battery cell.
Because the expansion of the battery core is mainly in the X direction, the expansion influence in the Y, Z direction is small, the homogenized material is defined according to isotropic materials, namely, the stress-strain relationship in the X direction of the homogenizing structure in the battery core can be used as all direction material parameters.
According to fig. 12, the proximal elastic segment and the plastic segment are identified, and the material parameter definition is performed in conjunction with the material definition keyword.
According to fig. 12, the strain is approximately a linear elastic segment at less than 0.08, and the elastic modulus is 2.634MPa.
Poisson's ratio is defined as 0.45.
The core material is defined as follows:
*MATERIAL,NAME＝mat-in
*ELASTIC,TYPE＝ISOTROPIC
2.634,0.45
*PLASTIC
0.2170,0
0.4751,0.01804
0.9405,0.02849
2.3634,0.03894。
in conclusion, through the internal structure expansion parameters of the battery cell defined by the application, the change of the internal structure rigidity at each stage of the expansion of the battery cell is truly reflected, and an important support is further provided for improving the simulation precision of the expansion of the battery cell.
Example two
Referring to fig. 13, an apparatus for defining expansion parameters of an internal structure of a battery cell includes:
the simplifying module is used for simplifying and defining the battery cell and defining a local coordinate system of the battery cell;
the first testing module is used for testing the expansion deformation of the battery cell in a free state;
the second testing module is used for testing the expansion force of the battery cell in different expansion gaps;
the first calculation module is used for calculating the relationship between the expansion deformation and the expansion force of the battery cell;
the simulation module is used for obtaining deformation load relation data of the battery cell shell under the battery cell expansion working condition in a simulation mode;
the second calculation module is used for calculating and obtaining stress-strain relation data in the X direction of the internal homogenization structure of the battery cell;
and the determining module is used for determining the internal homogenization structure complete expansion parameter of the battery cell.
Example III
Fig. 14 is a block diagram of a terminal according to an embodiment of the present application, and the terminal may be a terminal according to the above embodiment. The terminal may be a portable mobile terminal such as: smart phone, tablet computer. Terminals may also be referred to by other names, user equipment, portable terminals, etc.
Generally, the terminal includes: a processor 301 and a memory 302.
Processor 301 may include one or more processing cores, such as a 4-core processor, an 8-core processor, and the like. The processor 301 may be implemented in at least one hardware form of DSP (Digital Signal Processing ), FPGA (Field-Programmable Gate Array, field programmable gate array), PLA (Programmable Logic Array ). The processor 301 may also include a main processor, which is a processor for processing data in an awake state, also called a CPU (Central Processing Unit ), and a coprocessor; a coprocessor is a low-power processor for processing data in a standby state. In some embodiments, the processor 301 may integrate a GPU (Graphics Processing Unit, image processor) for rendering and drawing of content required to be displayed by the display screen. In some embodiments, the processor 301 may also include an AI (Artificial Intelligence ) processor for processing computing operations related to machine learning.
Memory 302 may include one or more computer-readable storage media, which may be tangible and non-transitory. Memory 302 may also include high-speed random access memory, as well as non-volatile memory, such as one or more magnetic disk storage devices, flash memory storage devices. In some embodiments, a non-transitory computer readable storage medium in memory 302 is used to store at least one instruction for execution by processor 301 to implement a cell internal structure expansion parameter definition method provided in the present application.
In some embodiments, the terminal may further optionally include: a peripheral interface 303, and at least one peripheral. Specifically, the peripheral device includes: at least one of radio frequency circuitry 304, touch screen 305, camera 306, audio circuitry 307, positioning component 308, and power supply 309.
The peripheral interface 303 may be used to connect at least one Input/Output (I/O) related peripheral to the processor 301 and the memory 302. In some embodiments, processor 301, memory 302, and peripheral interface 303 are integrated on the same chip or circuit board; in some other embodiments, either or both of the processor 301, the memory 302, and the peripheral interface 303 may be implemented on separate chips or circuit boards, which is not limited in this embodiment.
The Radio Frequency circuit 304 is configured to receive and transmit RF (Radio Frequency) signals, also known as electromagnetic signals. The radio frequency circuitry 304 communicates with a communication network and other communication devices via electromagnetic signals. The radio frequency circuit 304 converts an electrical signal into an electromagnetic signal for transmission, or converts a received electromagnetic signal into an electrical signal. Optionally, the radio frequency circuit 304 includes: antenna systems, RF transceivers, one or more amplifiers, tuners, oscillators, digital signal processors, codec chipsets, subscriber identity module cards, and so forth. The radio frequency circuitry 304 may communicate with other terminals via at least one wireless communication protocol. The wireless communication protocol includes, but is not limited to: the world wide web, metropolitan area networks, intranets, generation mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and/or WiFi (Wireless Fidelity ) networks. In some embodiments, the radio frequency circuitry 304 may also include NFC (Near Field Communication ) related circuitry, which is not limiting of the application.
The touch display screen 305 is used to display a UI (User Interface). The UI may include graphics, text, icons, video, and any combination thereof. The touch screen 305 also has the ability to collect touch signals at or above the surface of the touch screen 305. The touch signal may be input as a control signal to the processor 301 for processing. The touch screen 305 is used to provide virtual buttons and/or virtual keyboards, also known as soft buttons and/or soft keyboards. In some embodiments, the touch display 305 may be one, providing a front panel of the terminal; in other embodiments, the touch display screen 305 may be at least two, respectively disposed on different surfaces of the terminal or in a folded design; in still other embodiments, the touch display 305 may be a flexible display disposed on a curved surface or a folded surface of the terminal. Even more, the touch display screen 305 may be arranged in an irregular pattern that is not rectangular, i.e., a shaped screen. The touch display 305 may be made of LCD (Liquid Crystal Display ), OLED (Organic Light-Emitting Diode) or other materials.
The camera assembly 306 is used to capture images or video. Optionally, the camera assembly 306 includes a front camera and a rear camera. In general, a front camera is used for realizing video call or self-photographing, and a rear camera is used for realizing photographing of pictures or videos. In some embodiments, the number of the rear cameras is at least two, and the rear cameras are any one of a main camera, a depth camera and a wide-angle camera, so as to realize fusion of the main camera and the depth camera to realize a background blurring function, and fusion of the main camera and the wide-angle camera to realize a panoramic shooting function and a Virtual Reality (VR) shooting function. In some embodiments, camera assembly 306 may also include a flash. The flash lamp can be a single-color temperature flash lamp or a double-color temperature flash lamp. The dual-color temperature flash lamp refers to a combination of a warm light flash lamp and a cold light flash lamp, and can be used for light compensation under different color temperatures.
The audio circuit 307 is used to provide an audio interface between the user and the terminal. The audio circuit 307 may include a microphone and a speaker. The microphone is used for collecting sound waves of users and environments, converting the sound waves into electric signals, and inputting the electric signals to the processor 301 for processing, or inputting the electric signals to the radio frequency circuit 304 for voice communication. For the purpose of stereo acquisition or noise reduction, a plurality of microphones can be respectively arranged at different parts of the terminal. The microphone may also be an array microphone or an omni-directional pickup microphone. The speaker is used to convert electrical signals from the processor 301 or the radio frequency circuit 304 into sound waves. The speaker may be a conventional thin film speaker or a piezoelectric ceramic speaker. When the speaker is a piezoelectric ceramic speaker, not only the electric signal can be converted into a sound wave audible to humans, but also the electric signal can be converted into a sound wave inaudible to humans for ranging and other purposes. In some embodiments, the audio circuit 307 may also include a headphone jack.
The location component 308 is used to locate the current geographic location of the terminal to enable navigation or LBS (Location Based Service, location-based services). The positioning component 308 may be a positioning component based on the United states GPS (Global Positioning System ), the Beidou system of China, or the Galileo system of Russia.
The power supply 309 is used to power the various components in the terminal. The power source 309 may be alternating current, direct current, disposable or rechargeable. When the power source 309 comprises a rechargeable battery, the rechargeable battery may be a wired rechargeable battery or a wireless rechargeable battery. The wired rechargeable battery is a battery charged through a wired line, and the wireless rechargeable battery is a battery charged through a wireless coil. The rechargeable battery may also be used to support fast charge technology.
It will be appreciated by those skilled in the art that the structure shown in fig. 14 is not limiting of the terminal and may include more or fewer components than shown, or may combine certain components, or may employ a different arrangement of components.
Example IV
In an exemplary embodiment, a computer readable storage medium is also provided, on which a computer program is stored, which program, when being executed by a processor, implements a method for defining an expansion parameter of an internal structure of a cell as provided by all the inventive embodiments of the present application.
Any combination of one or more computer readable media may be employed. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
The computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, either in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider).
Example five
In an exemplary embodiment, an application program product is also provided, comprising one or more instructions executable by the processor 301 of the above device to perform the above method of defining a cell internal structure expansion parameter.
Although embodiments of the present application have been disclosed above, they are not limited to the use listed in the description and modes of implementation. It can be applied to various fields suitable for the present application. Additional modifications will readily occur to those skilled in the art. Therefore, the application is not to be limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.
Claims (11)
1. The method for defining the expansion parameters of the internal structure of the battery cell is characterized by comprising the following steps of:
step one, simplifying definition of a battery cell and defining a local coordinate system of the battery cell; the battery cell comprises a battery cell shell and a battery cell internal structure;
step two, testing the expansion deformation of the free state battery cell;
step three, testing the expansion force of the battery cell under different expansion gaps;
calculating the relationship between the expansion deformation and the expansion force of the battery cell;
step five, simulating to obtain deformation load relation data of the battery cell shell under the battery cell expansion working condition;
step six, calculating to obtain stress-strain relation data of the internal homogenization structure X direction of the battery cell;
and step seven, determining the complete expansion parameters of the internal homogenization structure of the battery cell.
2. The method for defining the expansion parameters of the internal structure of the battery cell according to claim 1, wherein the specific method of the first step is as follows:
11 Simplifying the battery cell shell into a hollow cuboid structure, wherein the cuboid size is determined according to the size of the battery cell shell; the internal structure of the battery cell is simplified into a homogenized cuboid structure;
12 Defining a local coordinate system of the battery cell; the center of the battery cell is an origin, the X axis is the thickness direction of the battery cell, the Z axis is vertical upwards, and the Y axis accords with the right-hand spiral rule; defining the X-direction dimension of the battery cell as the thickness of the battery cell, the Y-direction dimension as the width of the battery cell and the Z-direction dimension as the height of the battery cell; defining two vertical surfaces of the battery cell and the X axis as large surfaces of the battery cell, wherein the two vertical surfaces of the battery cell and the Z axis are respectively upper and lower surfaces, and the two vertical surfaces of the battery cell and the Y axis are side surfaces; half of the thickness of the overall structure of the battery cell is recorded as L 1 Half of the thickness of the internal homogenization structure of the battery cell is marked as L 2 The method comprises the steps of carrying out a first treatment on the surface of the The width dimension of the whole structure of the battery cell is recorded as W 1 The width dimension of the internal homogenization structure of the battery cell is marked as W 2 The method comprises the steps of carrying out a first treatment on the surface of the The height dimension of the overall structure of the battery cell is recorded as H 1 The height dimension of the internal homogenization structure of the battery cell is marked as H 2 The method comprises the steps of carrying out a first treatment on the surface of the The large area of the overall structure of the battery cell is marked as S 1 The large area of the homogenizing structure in the cell is marked as S 2 。
3. The method for defining the expansion parameters of the internal structure of the battery cell according to claim 1, wherein the specific method of the second step is as follows:
and the battery core is in a free state, and a full life cycle charge-discharge cycle test is carried out on the battery core, so that the relationship data of the expansion deformation and the cycle times of the whole structure of the battery core are obtained.
4. The method for defining the expansion parameters of the internal structure of the battery cell according to claim 2, wherein the specific method in the third step is as follows:
testing to obtain the charge-discharge expansion force data of the battery cell at different gaps according to L 1 Percentages are defined.
5. The method for defining the expansion parameters of the internal structure of the battery cell according to claim 2, wherein the specific method of the fourth step is as follows:
summarizing and drawing each gap and expansion force to obtain the relationship between each expansion gap and expansion force of the battery cell; and obtaining the relation between the deformation amount of the battery cell and the expansion force according to the relation between the equivalent deformation of the battery cell in the X direction and the clearance.
6. The method for defining the expansion parameters of the internal structure of the battery cell according to claim 2, wherein the specific method in the fifth step is as follows:
51 A 1/2 shell is obtained by cutting through an X-axis section passing through the origin of coordinates; simplifying the geometry of the battery cell shell to obtain a simplified structure of the cuboid thin-wall battery cell shell;
52 The geometry of the large surface of the battery cell shell is cut by utilizing the contour of the internal homogenization structure of the battery cell, so that a projection area of the internal homogenization structure on the large surface of the battery cell shell is obtained;
53 Performing finite element meshing;
54 Defining parameters of the cell shell material according to elastic materials, wherein the parameters comprise elastic modulus E and Poisson ratio mu;
55 Constraint and load definition; creating a distributed coupling unit: the independent nodes of the coupling units are unit nodes on the symmetrical cross section of the battery cell shell, and the subordinate nodes are defined as free nodes in the center of the symmetrical cross section; constraining the slave nodes; uniformly distributing load on grids in a projection area of an internal homogenization structure of a large surface of the battery cell;
56 Simulation analysis is carried out on the model; and defining the support reaction force of the shell as the product of the uniformly distributed pressure and the loading area, wherein the deformation of the shell is the deformation of the maximum node of the large-surface deformation of the cell shell, and obtaining the relation between the support reaction force of the cell shell in the X direction and the maximum deformation of the cell shell.
7. The method for defining the expansion parameters of the internal structure of the battery cell according to claim 1, wherein the specific method in the step six is as follows:
61 Linear fitting is carried out on the relation between the counter force of the cell shell in the X direction obtained by simulation and the maximum deformation of the cell shell, and a fitting curve R is required 2 ≥0.99；
62 Calculating the relation between the expansion force and the deformation of the internal structure of the battery cell;
the internal expansion force of the battery cell is recorded as f in Integral expansion of battery cellExpansion force f total Reaction force f of cell shell out The relation of (2) is:
f total ＝f in -f out (2)
the cell internal expansion force is calculated by the following formula:
f in ＝f total +f out (3)
thereby obtaining the relationship between the expansion force and the deformation of the internal structure of the battery cell;
63 Acquiring stress-strain relation of the homogenized structure in the cell in the X direction;
assuming uniform deformation of the internal structure in the X direction, the cross-sectional area S of the homogenized structure 2 The X-direction stress σ is calculated by the following formula:
the X-direction strain epsilon is calculated by the following formula:
based on the above, the stress-strain relationship of the internal homogenization structure of the battery cell is obtained.
8. The method for defining the expansion parameters of the internal structure of the battery cell according to claim 1, wherein the specific method in the step seven is as follows:
the homogenized material is defined according to isotropic material, namely, the stress-strain relation in the X direction of the homogenized structure inside the cell is used as the material parameter in all directions.
9. A cell internal structure expansion parameter defining device, comprising:
the simplifying module is used for simplifying and defining the battery cell and defining a local coordinate system of the battery cell;
the first testing module is used for testing the expansion deformation of the battery cell in a free state;
the second testing module is used for testing the expansion force of the battery cell in different expansion gaps;
the first calculation module is used for calculating the relationship between the expansion deformation and the expansion force of the battery cell;
the simulation module is used for obtaining deformation load relation data of the battery cell shell under the battery cell expansion working condition in a simulation mode;
the second calculation module is used for calculating and obtaining stress-strain relation data in the X direction of the internal homogenization structure of the battery cell;
and the determining module is used for determining the internal homogenization structure complete expansion parameter of the battery cell.
10. A terminal, comprising:
one or more processors;
a memory for storing the one or more processor-executable instructions;
wherein the one or more processors are configured to:
a method of defining the internal structural expansion parameters of a cell according to any one of claims 1 to 8.
11. A non-transitory computer readable storage medium, characterized in that instructions in the storage medium, when executed by a processor of a terminal, enable the terminal to perform a cell internal structure expansion parameter definition method according to any of claims 1 to 8.
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| CN202310788915.2A CN116861735A (en) | 2023-06-30 | 2023-06-30 | Method, device, terminal and storage medium for defining expansion parameters of internal structure of battery cell |
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