Pole piece, battery cell and battery cell physical quantity detection system

Abstract

The invention provides a pole piece, a battery cell and a battery cell physical quantity detection system.The pole piece comprises a pole piece body, the pole piece body is divided into at least one pole piece area, and the pole piece body is connected with a power end through a connecting end; and the test terminal on the pole piece body sends a regional electric signal of the pole piece region to the electric signal detection component. In practical application, one battery cell can comprise a plurality of pole pieces. According to the scheme of the invention, the battery cell can be provided with a plurality of test terminals. And the electric signal of the pole piece area of each pole piece of the battery cell can be transmitted to the electric signal detection component through the test terminal, so that the physical quantity distribution of the battery cell can be calculated. Compared with the prior art in which the overall electrical signal of the battery cell is directly used as the basis of physical quantity distribution detection, the scheme of the invention at least provides the regional electrical signals of the plurality of pole pieces as the basis of physical quantity distribution detection, and can improve the accuracy of the physical property acquisition result in the battery cell.

Description

Technical Field

[0001] The present application relates to the technical field of power batteries, and in particular to a pole piece, a battery cell, and a battery cell physical quantity detection system. Background Art

[0002] Lithium-ion batteries have the advantages of high voltage platform, high energy density, long cycle life, etc., and are widely used in the field of pure electric vehicles and hybrid electric vehicles. With the increasing performance requirements for lithium-ion batteries, high energy density, high rate charge and discharge, low heat generation, high safety and other performance requirements have become the necessary indicators of high-end lithium-ion batteries at this stage. Because lithium-ion batteries store and release energy through the directional lithium deintercalation behavior of positive and negative active materials, the amount of lithium deintercalation determines the state of charge of the battery. When lithium batteries are in use, there are multiple physical fields such as thermal field, electric field, and chemical field inside the lithium battery. Under the coupling of various physical fields, the temperature and charge state of different positions inside the battery cell are uneven. Some positions will be over-embedded or the temperature is too high, causing the growth of lithium dendrites, capacity decay, and even touching the safety bottom line. This phenomenon is more obvious during high rate charge and discharge. In order to achieve the higher performance index requirements of lithium batteries, it is necessary to determine the distribution of physical quantities inside the battery cell. To this end, an analysis model is established in the prior art for the internal physical quantity distribution of the battery cell. When the analysis model is used, the overall external electrical characteristics of the battery cell are detected after applying a test voltage to the battery cell as the input parameters of the analysis model, and the analysis model can calculate the physical quantity distribution inside the battery cell. However, when the physical quantity distribution inside the battery cell is complex and has poor uniformity, the results of analyzing the physical quantity distribution inside the battery cell using only the overall external electrical characteristics of the battery cell are low in accuracy. Summary of the invention

[0003] The technical problem to be solved by the present application is that the accuracy of obtaining the physical properties inside the battery cell in the prior art is low, which makes it difficult for the performance of lithium batteries to further develop towards high performance. To this end, the present application provides a pole piece, a battery cell and a battery cell physical quantity detection system.

[0004] In a first aspect, the technical solution of the present application provides a pole piece, comprising:

[0005] A pole piece body, comprising at least one pole piece region;

[0006] A connection end, formed on an edge of the pole piece body, and used to connect to a power supply end;

[0007] A test terminal is formed on the other edge of the pole piece body, and each of the test terminals corresponds to one of the pole piece regions;

[0008] The test terminal is used to be electrically connected to the electric signal detection component, and after the connection end is connected to the test electric signal, the regional electric signal corresponding to the electrode area is sent to the electric signal detection component.

[0009] In some embodiments, the pole piece body comprises an aluminum foil body and an insulating layer wrapped around the aluminum foil body;

[0010] The test terminal includes an aluminum foil connecting portion extending outward from the aluminum foil main body at the electrode area.

[0011] In some embodiments of the electrode sheet, the width of the test terminal is greater than a set width threshold, and the set width threshold is a width value that ensures that the test terminal can be used normally under test pressure.

[0012] In some embodiments, the number of the pole piece area and the number of the test terminals is: K = A × (L / H);

[0013] Among them, K is the number of the test terminals, A is the setting coefficient, L is the length of the pole piece body, and H is the width of the pole piece body.

[0014] In some embodiments of the pole piece, the test terminals are evenly distributed along the edge extension direction of the pole piece body.

[0015] In some embodiments of the pole piece, the number of the test terminal is one, which is arranged at the center line of the pole piece body.

[0016] In some embodiments of the electrode, the width B of the test terminal is H / J; the height G of the test terminal is H / I;

[0017] Wherein, B is the width of the test terminal, G is the height of the test terminal, and I and J are setting coefficients.

[0018] In a second aspect, the technical solution of the present application provides a battery cell, comprising an even number of pairs of pole pieces provided by the technical solution of the first solution, wherein the pole pieces are stacked.

[0019] In some solutions of the battery cell, all electrode areas corresponding to the same position are stacked to obtain the battery cell area, and the same position refers to the same position on the long side of the battery cell or the same position on the short side.

[0020] In a third aspect, the technical solution of the present application provides a battery cell physical quantity detection system, wherein the detected battery cell is the battery cell described in the second aspect; the system comprises:

[0021] A test power supply, whose power supply end is connected to the connection end of each pole piece in the tested battery cell, and the test power supply is used to input a test electrical signal to each pole piece;

[0022] An electrical signal detection component, the electrical signal detection component is electrically connected to each test terminal of the detected battery cell; after the electrode receives the test electrical signal, the regional electrical signal of the corresponding electrode area output by each test terminal is detected;

[0023] The regional physical quantity acquisition unit receives the regional electrical signal of each of the pole piece regions sent by the electrical signal detection component; the regional physical quantity acquisition unit determines the physical quantity distribution value of each of the pole piece regions through a pre-stored physical quantity analysis model.

[0024] In some schemes of the battery cell physical quantity detection system, in the battery cell, the regional physical quantity acquisition unit combines the physical quantity distribution values ​​of each electrode area in each battery cell area of ​​the detected battery cell to obtain the physical quantity distribution value of each battery cell area.

[0025] In some schemes of the battery cell physical quantity detection system, the regional physical quantity acquisition unit arranges the physical quantity distribution values ​​of each electrode area in the battery cell area in sequence to obtain the physical quantity distribution result of the battery cell area in the thickness direction.

[0026] The above technical solution has the following beneficial effects:

[0027] The present application provides a pole piece, a battery cell, and a battery cell physical quantity detection system, wherein the pole piece includes a pole piece body, the pole piece body is divided into at least one pole piece area, the pole piece body can be connected to the power supply end through a connection end, and when the power supply end inputs a test electrical signal, the test terminal on the pole piece body can send the regional electrical signal of the pole piece area to the electrical signal detection component. In actual application, the pole piece is the smallest conductive unit in the battery cell, and a battery cell may include multiple pole pieces, which are stacked. Through the scheme of the present application, the battery cell can have multiple test terminals. Through the test terminal, the pole piece area electrical signal of each pole piece of the battery cell can be transmitted to the electrical signal detection component for calculating the physical quantity distribution of the battery cell. Compared with the prior art that directly uses the overall electrical signal of the battery cell as the basis for physical quantity distribution detection, the scheme of the present application at least provides the regional electrical signals of multiple pole piece areas as the basis for physical quantity distribution detection, which can improve the accuracy of the results of obtaining the physical characteristics inside the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the division result of the pole piece area according to an embodiment of the present application;

[0029] Figure 2 This is a schematic diagram of the structure of a pair of pole pieces placed relatively to each other according to an embodiment of the present application;

[0030] Figure 3This is a schematic diagram of the structure after multiple pole pieces are stacked according to an embodiment of the present application;

[0031] Figure 4 A schematic diagram of the distribution of physical quantities in the thickness direction of a battery cell according to an embodiment of the present application;

[0032] Figure 5 This is a schematic diagram of the regional electrical signal detection structure of the electrode area described in one embodiment of the present application. DETAILED DESCRIPTION

[0033] The specific implementation of the present application is further described below with reference to the accompanying drawings.

[0034] It is easy to understand that according to the technical solution of the present application, without changing the essential spirit of the present application, a variety of structural modes and implementation modes that can be replaced by those skilled in the art can be replaced with each other. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present application, and should not be regarded as the entirety of the present application or as a limitation or restriction on the technical solution of the application.

[0035] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to different positions and different usage conditions. Therefore, these or other directional terms should not be interpreted as restrictive terms.

[0036] This embodiment provides a pole piece, such as Figure 1 and Figure 2 As shown, the pole piece includes a pole piece body 10, and at least one pole piece area 101 is obtained by partitioning on the pole piece body 10. A connection terminal is formed on the pole piece body 10, and the connection terminal is formed on an edge of the pole piece body 10, and the connection terminal is used to connect to the power supply terminal; Figure 2 As shown, the connection terminal connected to the positive electrode is the positive electrode connection terminal 11, and the connection terminal connected to the negative electrode is the negative electrode connection terminal 12. Figure 2 As shown, at least one test terminal 13 is formed on the electrode body 10, and the test terminal 13 is formed on another edge of the electrode body 10, that is, on an edge different from the connection end. Each of the test terminals 13 corresponds to one of the electrode areas 101; the test terminal 13 is used to be electrically connected to the electrical signal detection component, and after the test electrical signal is input to the power supply end, the regional electrical signal corresponding to the electrode area 101 is sent to the electrical signal detection component.

[0037] In the above scheme, the pole piece body 10 includes multiple pole piece areas 101. In actual application, the pole piece body 10 as a whole can also be regarded as an area. In this case, a test terminal 13 can be set on the edge of the pole piece body 10. The setting position of the test terminal 13 can be in the middle or other selected position.

[0038] Since the pole piece is composed of a copper-aluminum current collector and an active material coating, when the connection end receives the current applied by the power supply end, the copper-aluminum current collector in the pole piece has resistivity, which will cause a potential gradient on the pole piece, that is, the potentials on different pole piece regions 101 will be different. This solution allocates a test terminal 13 to each pole piece region 101, and can test the potential of different pole piece regions 101 during the charging and discharging process of the power supply end, and obtain the potential gradient distribution results of different pole piece regions 101 as regional electrical signals. The regional electrical signals replace the overall external electrical signals of the battery cell in the prior art and are input into the existing analysis model, so that the accurate physical quantity distribution value of the pole piece region can be obtained.

[0039] In the solution provided in the above embodiment, the pole piece includes a pole piece body 10, and the pole piece body 10 is divided into at least one pole piece area 101. The pole piece body 10 can be connected to the power supply end through the connection end. When the power supply end inputs the test electrical signal, the test terminal 13 on the pole piece body 10 can send the regional electrical signal of the pole piece area 101 to the electrical signal detection component. In actual application, the pole piece is the smallest conductive unit in the battery cell. A battery cell may include multiple pole pieces, and the multiple pole pieces are stacked. Through the above solution, the battery cell can have multiple test terminals 13, and the pole piece area electrical signal of each pole piece of the battery cell can be transmitted to the electrical signal detection component through the test terminal 13, which is used to calculate the physical quantity distribution of the battery cell. Compared with the prior art that directly uses the overall electrical signal of the battery cell as the basis for physical quantity distribution detection, this solution at least provides the regional electrical signals of multiple pole piece areas as the basis for physical quantity distribution detection, which can improve the accuracy of the results of obtaining the physical characteristics inside the battery cell.

[0040] It should be noted that the physical quantities involved in this application include multiple parameters. The regional electrical signal measured by the scheme in the embodiment of this application is a parameter in the physical quantity. There is an analysis model in the prior art. After the regional electrical signal is input into the analysis model, the analysis model can automatically calculate other physical quantity parameters of the same pole piece area based on the regional electrical signal. In the scheme of this application, a test terminal 13 that can output electrical signals for different pole piece areas 101 can be formed, so that the analysis model can calculate the physical quantity parameters of each pole piece area 101, and then obtain the physical quantity distribution value of each pole piece area 101.

[0041] In some embodiments, the pole piece body 10 of the pole piece includes an aluminum foil body and an insulating layer wrapped around the aluminum foil body; the test terminal 13 includes an aluminum foil connection portion formed by extending the aluminum foil body at the pole piece region 101 to the outside. The pole piece of this embodiment is easy to process, and no other components are required. The test terminal 13 can be obtained by directly processing the aluminum foil connection portion by clamping, stretching, etc. when processing the aluminum foil body.

[0042] In some embodiments, the width of the electrode piece of the test terminal 13 is greater than a set width threshold, and the set width threshold is a width value that ensures the normal use of the test terminal 13 under the test pressure. The test pressure is an empirical value of the environmental pressure when the test terminal 13 is normally used, that is, when the test terminal 13 is normally used, the environmental pressure has no effect on the reliability of the test terminal 13, ensuring that the test terminal 13 will not break accidentally.

[0043] The pole piece described in the above solution, the number of the pole piece area 101 and the test terminals 13 is: K=A×(L / H);

[0044] Among them, K is the number of the test terminals 13, A is the setting coefficient, L is the length of the pole piece body 10, and H is the width of the pole piece body 10. Theoretically, the more the number of pole piece regions 101, the more the number of regional electrical signals finally obtained, and the more accurate the detection results for supporting the distribution of physical quantities in the cell area will be. Taking into account the difficulty of processing and the computing load, the preferred number of embodiments of the present application is K=A×(L / H), and further, the setting coefficient A selects a value between 3-5. As shown in the figure, two pole pieces are included, one of which is used to connect the positive electrode and the other is used to connect the negative electrode, and the test terminals 13 on each pole piece are evenly and evenly distributed on the edge of the pole piece. In this embodiment, the width of the test terminal 13 is preferably B=H / J; the height of the test terminal 13 is G=H / I; wherein B is the width of the test terminal 13, G is the height of the test terminal 13, I and J are setting coefficients, preferably, I is 12-20, and J is between 3-4.

[0045] In another embodiment, if Figure 3 As shown, there is one test terminal 13 , which is arranged at the center line of the pole piece body 10 . Figure 3The result after stacking multiple pole pieces is shown in the figure. It can be seen from the figure that each pole piece has a test terminal 13 on the pole piece body 10. In specific implementation, the pole piece can be selected to have a length of L, a width of H, and a thickness of D. The connection on the pole piece body is used for an external power supply terminal. The test terminal 13 on the pole piece body 10 is used as an output terminal for potential output. The position of the test terminal 13 is set at L / 2, the ear height of the test terminal 13 is between H / I, and the width of the test terminal 13 is H / J.

[0046] In some embodiments of the present application, a battery cell is provided, comprising an even number of pairs of pole pieces provided in the above embodiment scheme, wherein the pole pieces are stacked, and the pole pieces are stacked as follows: Figure 2 and Figure 3 Through the battery cell of this solution, the potential of each electrode area in the battery cell can be sent to the electrical signal detection component to realize accurate calculation of the distribution of physical quantities inside the battery cell.

[0047] Furthermore, in the battery cell, all electrode regions corresponding to the same position are stacked to obtain the battery cell region, and the same position refers to the same position on the long side or the same position on the short side of the battery cell. Figure 1 and Figure 4 As shown, in the battery cell, all the electrode areas 101 corresponding to the same position are stacked to obtain a battery cell area, and the battery cell includes at least one battery cell area, and the same position refers to the same position on the long side of the battery cell or the same position on the short side. Figure 4 For example, the upper and lower directions include four pole pieces Q1, Q2, Q3 and Q4, and the surface can be divided into three pole piece areas, so that the pole piece areas of the four layers of pole pieces constitute the battery cell area, that is, S11, S21, S31 and S41 in the figure correspond to the first battery cell area, S12, S22, S32 and S42 correspond to the second battery cell area, and S13, S23, S33 and S43 correspond to the third battery cell area.

[0048] In some embodiments of the present application, a battery cell physical quantity detection system is provided, wherein the detected battery cell is the battery cell described in the above embodiment; the system comprises a test power supply, whose power supply end is connected to the connection end of each electrode piece in the detected battery cell, and the test power supply is used to input a test electrical signal to each electrode piece; Figure 5As shown, the system also includes an electrical signal detection component 20, and the electrical signal detection component 20 can be a multi-channel voltage acquisition instrument. Each channel of the multi-channel voltage acquisition instrument is electrically connected to the test terminal 13 of each of the pole pieces, and the regional electrical signal of the corresponding pole piece area output by the test terminal 13 is detected after the pole piece receives the test electrical signal. The system also includes a regional physical quantity acquisition unit, which receives the regional electrical signal of each of the pole piece areas sent by the electrical signal detection component; the regional physical quantity acquisition unit determines the physical quantity distribution value of each of the pole piece areas through a pre-stored physical quantity analysis model. The regional physical quantity acquisition unit arranges the physical quantity distribution values ​​of each pole piece area in the battery cell area in sequence to obtain the physical quantity distribution result of the battery cell area in the thickness direction. That is, in the up and down directions, each battery cell area contains four pole pieces, such as Figure 4 The first cell region includes S11, S21, S31 and S41. Arranging the distribution values ​​of the above four physical quantities gives the distribution results in the thickness direction. Figure 4 In the example of cell area division shown, the regional physical quantity acquisition unit combines the physical quantity distribution values ​​of each pole piece area 101 in each cell area to obtain the physical quantity distribution value of each cell area. In specific implementation, the multi-channel voltage acquisition instrument directly collects the physical quantity of each pole piece area. After the physical quantity distribution of each pole piece area is determined, the physical quantity distribution of any cell area can be obtained by superimposing the physical quantity distribution values ​​of each pole piece area in the cell area. After the physical quantity distribution value of each cell area is determined, it is equivalent to obtaining the physical quantity distribution result inside the cell from left to right.

[0049] The above scheme of the present application arranges voltage and current lines on the connection end, and performs charge and discharge tests on the battery cell composed of a single pair of pole pieces or multiple pairs of pole pieces. At the same time, voltage lines are added to each test terminal to realize real-time monitoring of the potential of each pole piece area position of the battery cell during the charge and discharge process. As shown in the figure, when it is specifically implemented, the connection end can also be connected to the electric signal detection component 20, and the detection result of the output potential of each test terminal 13 and the input potential of the connection end can be used as the difference of the electric signal detection result output by the test terminal. For example, the potential difference between the test terminal and the power supply end at different positions of the multi-channel voltage collector can be used. The regional electrical signal of each area is substituted into the existing physical quantity analysis model, and the physical quantity distribution result of each pole piece area can be analyzed. According to actual needs, the physical quantity distribution values ​​of different pole piece areas are combined or arranged in sequence, so that the physical quantity distribution results of the battery cell in different situations in the thickness, width, and height directions can be accurately tested, providing technical support for improving the performance of the battery cell.

[0050] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0051] The above are only the principles and preferred embodiments of the present application. It should be noted that, for ordinary technicians in this field, on the basis of the principles of the present application, several other modifications can be made, which should also be considered as the protection scope of the present application.

Claims

1. A pole piece, characterized in that: include: A pole piece body, comprising at least one pole piece region; A connection end, formed on an edge of the pole piece body, and used to connect to a power supply end; A test terminal is formed on the other edge of the pole piece body, and each of the test terminals corresponds to one of the pole piece regions; The test terminal is used to be electrically connected to the electric signal detection component, and after the connection end is connected to the test electric signal, the regional electric signal corresponding to the electrode area is sent to the electric signal detection component.

2. The pole piece according to claim 1, characterized in that: The pole piece body comprises an aluminum foil body and an insulating layer coated outside the aluminum foil body; The test terminal includes an aluminum foil connecting portion extending outward from the aluminum foil main body at the electrode area.

3. The pole piece according to claim 1, characterized in that: The width of the test terminal is greater than a set width threshold, and the set width threshold is a width value that ensures that the test terminal is used normally under a test pressure.

4. The pole piece according to claim 3, characterized in that: The number of the electrode area and the test terminals is: K=A×(L / H); Among them, K is the number of the test terminals, A is the setting coefficient, L is the length of the pole piece body, and H is the width of the pole piece body.

5. The pole piece according to claim 4, characterized in that: The test terminals are evenly distributed along the extending direction of the edge of the pole piece body.

6. The pole piece according to claim 3, characterized in that: The number of the test terminal is one, and the test terminal is arranged at the center line of the pole piece body.

7. The pole piece according to any one of claims 4 to 6, characterized in that: The width B of the test terminal = H / J; the height G of the test terminal = H / I; Wherein, B is the width of the test terminal, G is the height of the test terminal, and I and J are setting coefficients.

8. A battery cell, characterized in that: The invention comprises an even number of pairs of pole pieces as described in any one of claims 1 to 7, wherein the pole pieces are stacked.

9. The battery cell according to claim 8, characterized in that: The cell region is obtained by stacking all the electrode regions corresponding to the same position, and the same position refers to the same position on the long side or the same position on the short side of the cell.

10. A battery cell physical quantity detection system, characterized in that: The battery cell to be tested is the battery cell according to claim 8 or 9; the system comprises: A test power supply, whose power supply end is connected to the connection end of each pole piece in the tested battery cell, and the test power supply is used to input a test electrical signal to each pole piece; An electrical signal detection component, the electrical signal detection component is electrically connected to each test terminal of the detected battery cell; after the electrode receives the test electrical signal, the regional electrical signal of the corresponding electrode area output by each test terminal is detected; The regional physical quantity acquisition unit receives the regional electrical signal of each of the pole piece regions sent by the electrical signal detection component; the regional physical quantity acquisition unit determines the physical quantity distribution value of each of the pole piece regions through a pre-stored physical quantity analysis model.

11. The battery cell physical quantity detection system according to claim 10, characterized in that: The regional physical quantity acquisition unit combines the physical quantity distribution values ​​of each electrode area in each of the battery cell areas of the detected battery cell to obtain the physical quantity distribution value of each of the battery cell areas.

12. The battery cell physical quantity detection system according to claim 11, characterized in that: The regional physical quantity acquisition unit arranges the physical quantity distribution values ​​of each pole piece region in the battery cell region in sequence to obtain the physical quantity distribution result of the battery cell region in the thickness direction.

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