A battery cell film color detection device and detection method

Abstract

The present application provides a cell film color detection device and a detection method, which belong to the field of solar cell manufacturing. The cell film color detection device includes a trough body and a pressing piece, the trough body has a cavity for accommodating a dielectric solution and a cell; the trough body has a cavity for accommodating a dielectric solution and a cell; the pressing piece is configured to be able to extend into and out of the cavity, and after the pressing piece extends into the cavity to a preset position, the distance between the bottom of the pressing piece and the bottom of the trough body allows at least one cell to be accommodated, and the pressing piece is configured to be able to observe the film color of the cell through the bottom of the pressing piece and the top of the pressing piece will not be immersed in the dielectric solution. The detection device can solve the problem of low film color detection accuracy and detection efficiency to a certain extent, and at the same time, it can also save detection costs. In addition, the present application also provides a cell film color detection method.

Description

Technical Field

[0001] The present application relates to the field of solar cells, and in particular to a device and method for detecting the film color of a solar cell. Background Art

[0002] In the prior art, the film color detection of battery cells is generally carried out through an automatic film color monitoring system or by sampling the battery cells for component lamination. However, the automatic film color monitoring system has problems such as low detection sensitivity and easy detection errors, and the component lamination detection method has problems such as high detection efficiency and detection cost. Summary of the invention

[0003] The purpose of the present application is to provide a battery cell film color detection device and detection method, which can solve the problems of low film color detection accuracy and detection efficiency to a certain extent, and at the same time, can save detection costs.

[0004] The embodiment of the present application is implemented as follows:

[0005] The embodiment of the present application provides a battery cell film color detection device, comprising a tank body and a tablet pressing member. The tank body has a cavity for accommodating a medium solution and a battery cell; the tablet pressing member is configured to be able to extend into and out of the cavity, and after the tablet pressing member extends into the cavity to a preset position, the distance between the bottom of the tablet pressing member and the bottom of the tank body allows at least one battery cell to be accommodated, and the tablet pressing member is configured to be able to observe the film color of the battery cell through the bottom of the tablet pressing member and the top of the tablet pressing member will not be immersed in the medium solution.

[0006] In the above technical scheme, by using the above device, the dielectric solution can be used to simulate the cross-linking material used in the component lamination, and the pressing piece can be used to simulate the glass used in the component lamination process. Through the mutual cooperation of the dielectric solution, the battery cell and the pressing piece, the same effect as the battery cell component lamination can be achieved, thereby realizing the detection of the battery cell film color. Moreover, compared with the real battery cell component lamination detection method, the detection device not only has the advantage of high film color detection accuracy, but also has the huge advantages of high detection efficiency (short assembly and detection time of the detection device) and low detection cost (low material cost of the detection device and can be reused).

[0007] In some optional embodiments, the pressing piece includes a bottom wall and a side wall connected to the bottom wall, and the bottom wall and the side wall together form a groove with an opening direction toward the top of the trough body, so that the top of the pressing piece will not be immersed in the medium solution, and the pressing piece is configured to be able to observe the film color of the battery cell through the bottom wall.

[0008] In the above technical solution, the pressing piece is configured to have a groove in order to better prevent both the upper and lower surfaces of the pressing piece from being immersed in the solution, thereby ensuring the accuracy of the film color detection of the battery cell.

[0009] In some optional embodiments, in the height direction of the trough body, the height of the side wall is greater than or equal to the height of the trough body.

[0010] In the above technical solution, in the height direction of the groove body, the height of the side wall is set to be greater than or equal to the height of the groove body in order to more effectively prevent the dielectric solution from entering the groove, thereby further ensuring the accuracy of the battery cell film color detection.

[0011] In some optional embodiments, the pressing member is configured to meet the following condition: in the height direction of the trough body, the orthographic projection of the battery sheet does not exceed the orthographic projection of the pressing member.

[0012] In the above technical solution, in the height direction of the trough body, the orthographic projection of the battery cell does not exceed the orthographic projection of the pressing piece, so that the film color of the entire battery cell can be observed through the bottom wall of the pressing piece, thereby realizing the film color detection of the entire battery cell and avoiding the problem of missed film color detection.

[0013] In some optional embodiments, the ratio of the surface area of ​​the bottom wall to the surface area of ​​the battery cell is (3-5):1.

[0014] In the above technical solution, the ratio of the surface area of ​​the bottom wall of the pressing piece to the surface area of ​​the battery cell is limited to the range of (3 to 5): 1 in order to make the bottom wall of the pressing piece have an appropriate size, so that the film color detection of multiple battery cells can be achieved in one operation, thereby greatly improving the detection efficiency.

[0015] In some optional embodiments, the bottom wall is made of glass.

[0016] In the above technical solution, the material of the bottom wall of the pressing piece is set to glass because glass is also used in component lamination. The use of glass can make the film color detection device closer to the actual component lamination, so that the film color of the battery cell can be detected more accurately.

[0017] In some optional embodiments, the material of the glass is the same as the material of the glass used for the cell in the assembly lamination process.

[0018] In the above technical solution, the same material as the glass used for the battery cells in the component lamination process is used, which can more realistically simulate the component lamination and thus more realistically reflect the film color of the battery cells.

[0019] In some optional embodiments, the side walls are perpendicular to the bottom wall.

[0020] In the above technical solution, the side wall and the bottom wall of the tablet pressing member are arranged in a vertical form because this arrangement can make the overall structure of the tablet pressing member more regular, thereby facilitating process preparation.

[0021] In a second aspect, an embodiment of the present application provides a method for detecting the film color of a cell, which is performed using the cell film color detection device provided in the embodiment of the first aspect, and includes the following steps:

[0022] A battery cell and a dielectric solution are placed in the cavity, wherein the refractive index of the dielectric solution matches the refractive index of the cross-linked material used in the lamination process of the battery cell;

[0023] Extending the pressing piece into the cavity and reaching a preset position;

[0024] On the side of the pressing piece away from the battery cell, the film color of the battery cell is detected through the pressing piece and the dielectric solution.

[0025] In the above technical scheme, the battery cell film color detection device provided by the first aspect embodiment is adopted, and the film color detection of the battery cell is performed according to the above method, which can achieve the same technical effect as the component lamination, thereby realizing the film color detection of the battery cell. Moreover, compared with the real battery cell component lamination detection method, the detection device not only has the advantage of high film color detection accuracy, but also has the huge advantages of high detection efficiency and low detection cost.

[0026] In some optional embodiments, the medium solution includes one or more of water, alcohol, methanol, isopropanol and sodium chloride solution.

[0027] In the above technical solution, the types of medium solutions are limited to the above range because the refractive index of these solutions is relatively close to the refractive index of the cross-linking material used in the component lamination process. The use of these solutions can more realistically simulate the component lamination. In addition, these solutions also have the advantages of being green, safe and inexpensive.

[0028] In some optional embodiments, the ratio of the surface area of ​​the bottom of the pressing piece to the surface area of ​​the battery cell is (3-5):1; during the detection process, multiple battery cells are distributed at intervals in the cavity, and the pressing piece and the multiple battery cells are set correspondingly.

[0029] In the above technical solution, the multiple battery cells are distributed at intervals, and the pressing pieces are arranged corresponding to the multiple battery cells, which can avoid overlapping of adjacent battery cells, thereby ensuring that there will be no problem of partial missed detection when detecting multiple battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic diagram of the structure of a battery cell film color detection device provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of another battery cell film color detection device provided in an embodiment of the present application;

[0033] Figure 3 A process flow chart of a method for detecting cell film color provided in an embodiment of the present application.

[0034] Icons: 10 - cell film color detection device; 100 - tank body; 110 - cavity; 200 - pressing piece; 210 - side wall; 220 - bottom wall; 230 - groove; 300 - cell; 400 - medium solution. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0036] It should be noted that “and / or” in this application, such as “Feature 1 and / or Feature 2”, refers to the three situations of “Feature 1” alone, “Feature 2” alone, or “Feature 1” plus “Feature 2”.

[0037] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" in "one or more" refers to two or more; the range of "value a ~ value b" includes the two end values ​​"a" and "b", and the "unit" in "value a ~ value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0038] The following is a detailed description of a cell film color detection device and a detection method according to an embodiment of the present application.

[0039] In the prior art, the existing film color detection methods all have their own problems. Among them, the automatic film color monitoring system cannot truly reflect the film color of the battery cell due to its low detection sensitivity, resulting in errors in the film color detection results. Although the component lamination detection method can truly reflect the film color of the battery cell, the lamination equipment is accompanied by a large amount of odor and dust, which can easily cause pollution to the battery cell, thereby affecting the quality of the battery; at the same time, a large amount of adhesive film materials and glass are required in the lamination process, and these materials cannot be reused, resulting in excessively high detection costs; in addition, the component lamination detection method requires time to assemble the battery cells, and only one group of battery cells can be laminated at a time, plus the lamination takes about an hour, resulting in low detection results, and cannot be applied to large-scale battery cell film color detection.

[0040] Therefore, there is an urgent need for a cell film color detection technology with high detection accuracy, high detection efficiency and low detection cost.

[0041] The inventors have discovered that based on the detection principle of component lamination, providing a corresponding substitute for each component in the component lamination can successfully simulate component lamination, thereby achieving the same technical effect as component lamination and further realizing the film color detection of the battery cell.

[0042] More importantly, compared with the actual battery cell 300 assembly lamination detection method, this detection method not only has the advantage of high film color detection accuracy, but also has the huge advantages of high detection efficiency and low detection cost.

[0043] See also Figure 1 The embodiment of the present application provides a battery cell film color detection device 10, comprising a tank body 100 and a pressing piece 200. The tank body 100 has a cavity 110 for accommodating a medium solution 400 and a battery cell 300; the pressing piece 200 is configured to be able to extend into and out of the cavity 110, and after the pressing piece 200 extends into the cavity 110 to reach a preset position, the distance between the bottom of the pressing piece 200 and the bottom of the tank body 100 allows at least one battery cell 300 to be accommodated, and the pressing piece 200 is configured to be able to observe the film color of the battery cell 300 through the bottom of the pressing piece 200 and the top of the pressing piece 200 will not be immersed in the medium solution 400.

[0044] In the present application, by using the above-mentioned device, the dielectric solution 400 can be used to simulate the cross-linking material used in the component lamination, and the pressing piece 200 can be used to simulate the glass used in the component lamination process. Through the mutual cooperation of the dielectric solution 400, the battery cell 300 and the pressing piece 200, the same effect as the battery cell 300 component lamination can be achieved, thereby realizing the detection of the film color of the battery cell 300. In addition, compared with the actual battery cell 300 component lamination detection method, the detection device not only has the advantage of high film color detection accuracy, but also has the huge advantages of high detection efficiency (short assembly and detection time of the detection device) and low detection cost (low material cost of the detection device and can be reused).

[0045] It should be noted that the method of controlling the tablet pressing member 200 to extend into and out of the cavity 110 is not specifically limited, and it can be done manually or by providing a drive mechanism that can be extended up and down above the tablet pressing member 200 .

[0046] It is understandable that the specific form of the driving mechanism is not limited and can be configured in a conventional manner in the art.

[0047] As an example, the driving mechanism is a telescopic cylinder.

[0048] It should be noted that the distance from the bottom of the pressing member 200 to the upper surface of the battery cell 300 is not limited and can be adjusted according to the thickness of the battery cell 300 .

[0049] As an example, in the height direction of the trough body 100, the distance from the bottom of the pressing piece 200 to the upper surface of the battery cell 300 is 0 to 5 mm, for example but not limited to any point value of 0 mm, 1 mm, 2 mm, 3 mm, 4 mm and 5 mm, or a range value between any two of them.

[0050] It should be noted that the surface of the battery cell 300 is not flat but has a velvet structure. Therefore, even if the distance from the bottom of the pressing piece 200 to the upper surface of the battery cell 300 is 0, there will be a dielectric solution 400 between the two, which can also be used to detect the film color of the battery cell 300.

[0051] It should be noted that the “bottom” refers to the pressing piece 200 being an overall regular structure. For example, the pressing piece 200 is a rectangular parallelepiped, and the “bottom” refers to the side of the pressing piece 200 close to the tank body 100 .

[0052] It should be noted that in order to effectively prevent the dielectric solution 400 from interfering with the film color detection of the battery cell 300 , the structure of the pressing member 200 may be optimized.

[0053] See also Figure 2As an example, the pressing piece 200 includes a bottom wall 220 and a side wall 210 connected to the bottom wall 220, and the bottom wall 220 and the side wall 210 together form a groove 230 with an opening direction toward the top of the trough body 100, so that the top of the pressing piece 200 will not be immersed in the medium solution 400, and the pressing piece 200 is configured to be able to observe the film color of the battery cell 300 through the bottom wall 220.

[0054] In this embodiment, the pressing piece 200 is configured to have a groove 230 in order to better prevent both the upper and lower surfaces of the pressing piece 200 from being immersed in the solution, thereby ensuring the accuracy of film color detection of the battery cell 300 .

[0055] It should be noted that the “bottom wall” 220 refers to the form of the tablet pressing member 200 having the groove 230 , and needs to be distinguished from the overall structure of the tablet pressing member 200 which is a relatively regular form.

[0056] It should be noted that the height of the side wall 210 of the tablet pressing member 200 is not specifically limited, as long as the medium solution 400 can be prevented from entering the groove 230 .

[0057] It should be noted that the shapes of the bottom of the trough body 100 and the bottom wall 220 of the tablet pressing member 200 are not specifically limited and may be square, quadrilateral or circular.

[0058] As an example, the bottom of the trough body 100 and the bottom wall 220 of the pressing piece 200 are both square in shape.

[0059] As an example, in the height direction of the tank body 100 , the height of the side wall 210 is greater than or equal to the height of the tank body 100 .

[0060] In this embodiment, in the height direction of the trough body 100, the height of the side wall 210 of the pressing piece 200 is set to be greater than or equal to the height of the trough body 100 in order to more effectively prevent the solution from entering the groove 230, thereby further ensuring the accuracy of the film color detection of the battery cell 300.

[0061] It should be noted that there is no limitation on the size relationship between the surface area of ​​the bottom wall 220 of the pressing member 200 and the surface area of ​​the battery cell 300, that is, the surface area of ​​the bottom wall 220 of the pressing member 200 can be set to the same form as the surface area of ​​the battery cell 300, or it can be set to a different form (including greater or less than two situations).

[0062] As an example, the pressing member 200 is configured to meet the following condition: in the height direction of the tank body 100 , the orthographic projection of the battery cell 300 does not exceed the orthographic projection of the pressing member 200 .

[0063] In this embodiment, in the height direction of the trough body 100, the orthographic projection of the battery cell 300 does not exceed the orthographic projection of the pressing piece 200. This is to enable the film color of the entire battery cell 300 to be observed through the bottom wall 220 of the pressing piece 200, thereby realizing film color detection of the entire battery cell 300 and avoiding the problem of missed film color detection.

[0064] As an example, the ratio of the surface area of ​​the bottom wall 220 to the surface area of ​​the battery cell 300 is (3-5):1, for example but not limited to, the surface area ratio is any point value among 3:1, 4:1 and 5:1 or a range value between any two of them.

[0065] In this embodiment, the ratio of the surface area of ​​the bottom wall 220 of the pressing member 200 to the surface area of ​​the battery cell 300 is limited to the range of (3 to 5): 1 in order to make the bottom wall 220 of the pressing member 200 have an appropriate size, so that the film color detection of multiple battery cells 300 can be achieved in one operation, thereby greatly improving the detection efficiency.

[0066] As an example, the length and width of the battery cell 300 are both 210 mm, and the length and width of the bottom wall 220 are both 500 mm.

[0067] As an example, the bottom wall 220 is made of glass.

[0068] In this embodiment, the material of the bottom wall 220 of the pressing member 200 is set to glass because glass is also used in component lamination. The use of glass can make the film color detection device closer to the actual component lamination, so that the film color of the battery cell 300 can be detected more accurately.

[0069] As an example, the material of the glass is the same as the material of the glass used in the component lamination process of the cell 300 .

[0070] In this embodiment, the same material as the glass used in the component lamination process of the battery cell 300 is used, which can more realistically simulate the component lamination and thus more realistically reflect the film color of the battery cell 300 .

[0071] It should be noted that the angle between the side wall 210 of the tablet pressing member 200 and the bottom wall 220 of the tablet pressing member 200 is not specifically limited, and can be set to a vertical form, an acute angle form, or an obtuse angle form.

[0072] As an example, the side wall 210 is perpendicular to the bottom wall 220 (ie, the angle between the side wall 210 and the bottom wall 220 is 90°).

[0073] In this embodiment, the side wall 210 and the bottom wall 220 of the tablet pressing member 200 are arranged in a vertical form because this arrangement can make the overall structure of the tablet pressing member 200 more regular, thereby facilitating process preparation.

[0074] In a second aspect, an embodiment of the present application provides a method for detecting the film color of a cell, which is performed using the cell film color detection device provided in the embodiment of the first aspect, and includes the following steps:

[0075] A battery cell and a dielectric solution are placed in the cavity, wherein the refractive index of the dielectric solution matches the refractive index of the cross-linked material used in the lamination process of the battery cell;

[0076] Extending the pressing piece into the cavity and reaching a preset position;

[0077] On the side of the pressing piece away from the battery cell, the film color of the battery cell is detected through the pressing piece and the dielectric solution.

[0078] In the present application, the battery cell film color detection device provided in the first aspect embodiment is adopted, and the film color detection of the battery cell is performed according to the above method, which can achieve the same technical effect as the component lamination, thereby realizing the film color detection of the battery cell. Moreover, compared with the actual battery cell component lamination detection method, the detection device not only has the advantage of high film color detection accuracy, but also has the huge advantages of high detection efficiency and low detection cost.

[0079] It should be noted that the order of adding the battery cells and the dielectric solution is not specifically limited, and the battery cells may be added first and then the dielectric solution, or the dielectric solution may be added first and then the battery cells.

[0080] As an example, the cell film color detection method is as follows Figure 3 shown.

[0081] It should be noted that the type of the dielectric solution is not specifically limited and can be selected according to the refractive index of the cross-linking material used in the module lamination process of the cell.

[0082] As an example, the medium solution includes one or more of water, alcohol, methanol, isopropanol and sodium chloride solution.

[0083] In this embodiment, the types of medium solutions are limited to the above range because the refractive index of these solutions is relatively close to the refractive index of the cross-linking material used in the component lamination process. The use of these solutions can more realistically simulate the component lamination. In addition, these solutions also have the advantages of being green, safe and inexpensive.

[0084] It should be noted that the concentration of sodium chloride in the sodium chloride solution is not specifically limited and can be adjusted according to actual needs.

[0085] As an example, the ratio of the surface area of ​​the bottom of the pressing piece to the surface area of ​​the battery cell is (3-5):1; during the detection process, multiple battery cells are distributed in the cavity at intervals, and the pressing piece and the multiple battery cells are set correspondingly.

[0086] In this embodiment, the plurality of battery cells are distributed at intervals, and the pressing pieces are arranged corresponding to the plurality of battery cells, which can avoid overlapping of adjacent battery cells, thereby ensuring that there will be no problem of partial missed detection when detecting the plurality of battery cells.

[0087] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0088] Example 1

[0089] The present application provides a method for detecting the film color of a battery cell, comprising the following steps:

[0090] Place 4 cells evenly spaced apart in the cavity of the tank, then add 1L of water, 24mL of ethanol, 25mL of isopropyl alcohol, and 250mL of pinene alcohol (the refractive index of the medium solution is equivalent to that of EVA) into the tank.

[0091] Then, the pressing piece is extended into the cavity until the distance between the bottom of the pressing piece and the upper surface of the battery cell is 2 mm;

[0092] Then, on the side of the bottom wall of the pressing member away from the battery cell, the film color of the battery cell is detected through the bottom wall of the battery cell and the dielectric solution.

[0093] Example 2

[0094] The embodiment of the present application provides a method for detecting the film color of a battery cell, which differs from the embodiment 1 only in that only one battery cell is placed in the cavity of the tank body.

[0095] Example 3

[0096] The present application provides a method for detecting the film color of a battery cell, comprising the following steps:

[0097] Place 4 cells evenly spaced apart in the cavity of the tank, then add 1L of water, 30mL of ethanol, 50mL of isopropanol, and 200mL of pinene alcohol (the refractive index of the medium solution is equivalent to that of EPE) into the tank.

[0098] Then, the pressing piece is extended into the cavity until the distance between the bottom of the pressing piece and the upper surface of the battery cell is 2 mm;

[0099] Then, on the side of the bottom wall of the pressing member away from the battery cell, the film color of the battery cell is detected through the bottom wall of the battery cell and the dielectric solution.

[0100] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

Claims

1. A cell film color detection device, characterized in that: include: A tank body, the tank body having a cavity for accommodating a dielectric solution and a battery cell; The refractive index of the medium solution matches the refractive index of the cross-linked material used in the lamination process of the cell, and the medium solution is used to simulate the cross-linked material used in the component lamination; The order of adding the battery cell and the dielectric solution is to first add the battery cell and then add the dielectric solution, or to first add the dielectric solution and then add the battery cell; as well as A pressing piece, wherein the pressing piece is configured to be able to extend into and out of the cavity, and after the pressing piece extends into the cavity to reach a preset position, the distance between the bottom of the pressing piece and the bottom of the trough body allows at least one of the battery cells to be accommodated, and the pressing piece is configured to be able to observe the film color of the battery cell through the bottom of the pressing piece and the top of the pressing piece will not be immersed in the medium solution.

2. The cell film color detection device according to claim 1, characterized in that: The pressing piece includes a bottom wall and a side wall connected to the bottom wall, wherein the bottom wall and the side wall together form a groove with an opening direction toward the top of the trough body, so that the top of the pressing piece will not be immersed in the medium solution, and the pressing piece is configured to be able to observe the film color of the battery cell through the bottom wall.

3. The cell film color detection device according to claim 2, characterized in that: In the height direction of the trough body, the height of the side wall is greater than or equal to the height of the trough body.

4. The cell film color detection device according to any one of claims 1 to 3, characterized in that: The pressing member is configured to meet the following condition: in the height direction of the trough body, the orthographic projection of the battery cell does not exceed the orthographic projection of the pressing member.

5. The cell film color detection device according to claim 2 or 3, characterized in that: The ratio of the surface area of ​​the bottom wall to the surface area of ​​the battery cell is (3-5):

1.

6. The cell film color detection device according to claim 2 or 3, characterized in that: The bottom wall is made of glass.

7. The cell film color detection device according to claim 6, characterized in that: The material of the glass is the same as the material of the glass used in the component lamination process of the cell.

8. A method for detecting the film color of a battery cell, characterized in that: The method is carried out using the cell film color detection device according to any one of claims 1 to 7, comprising the following steps: A battery cell and a dielectric solution are placed in the cavity, wherein the refractive index of the dielectric solution matches the refractive index of the cross-linked material used in the lamination process of the battery cell; Extending the pressing piece into the cavity and reaching the preset position; On a side of the pressing piece away from the battery cell, the film color of the battery cell is detected through the pressing piece and the medium solution.

9. The method for detecting the film color of a battery cell according to claim 8, characterized in that: The medium solution includes one or more of water, alcohol, methanol, isopropanol and sodium chloride solution.

10. The method for detecting the film color of a battery cell according to claim 8 or 9, characterized in that: The ratio of the surface area of ​​the bottom of the pressing piece to the surface area of ​​the battery cell is (3-5):1; during the detection process, a plurality of the battery cells are distributed at intervals in the cavity, and the pressing piece and the plurality of the battery cells are arranged correspondingly.

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