Battery cell tab leading-out structure

Abstract

The utility model provides a battery cell tab lead-out structure, which comprises a roll core, a core rod, a positive electrode adapter plate, a negative electrode adapter plate, a positive electrode confluence plate and a negative electrode confluence plate, the roll core is arranged on the periphery of the core rod, and a positive electrode positioned at one end of the roll core is connected to the positive electrode adapter plate through the positive electrode confluence plate; and the cathode at the other end of the roll core is connected to the cathode adapter sheet through the cathode bus sheet. According to the lead-out structure for the tabs of the battery cell, the positive electrode positioned at one end of the roll core is connected to the positive electrode adapter plate through the positive electrode confluence plate, the negative electrode positioned at the other end of the roll core is connected to the negative electrode adapter plate through the negative electrode confluence plate, and the large tabs are respectively led out from the two ends of the roll core, so that the overcurrent capability of the battery cell is improved; the adaptability of the battery cell in a high-rate use environment is effectively improved, the core rod is arranged, and the cooling channel is formed in the core rod, so that on one hand, the problems of high-rate charging and discharging and long-circulation internal high temperature of the energy storage device are solved, and on the other hand, the structural strength is supported, and the use experience of a user is improved.

Description

Technical Field

[0001] The utility model belongs to the field of new energy batteries, and in particular relates to a battery cell tab lead-out structure. Background Art

[0002] With the development of the new energy industry, the current trend is toward larger products and larger models. Considering existing product designs, heat generation during battery use is a factor that affects product performance. Some products incorporate liquid cooling systems for the cell rods. Space limitations lead to compartmentalized tabs, complicating tab extraction. Another key design consideration is the flow capacity of structural components. Sufficient flow area can effectively reduce heat generation during electron transfer. The increased capacity of lithium-ion batteries in recent years means that input and output currents are increasing at the same rate. Furthermore, supercapacitors, with high power output as their key characteristic, are also seeing an increase in their use of high currents. Within the overall product structure, the tab extraction structure in products with large or full tab structures becomes a key factor in limiting current output.

[0003] In existing technology, cells with positive and negative electrodes leading out from the same side are a major trend in the current battery industry. Externally, they are rectangular in shape, with the positive and negative electrodes and pressure relief valve located at the top. The outer shell is typically stamped. Internally, the tabs on the winding core are located on the same side, with both positive and negative tabs located at the top, on the left and right sides, respectively. The winding core is a flat structure with no filler in the middle, and is directly compacted. A single cell consists of two winding cores connected in parallel.

[0004] The disadvantages of this structure in the prior art are: 1) The heat dissipation capacity of the battery cell is poor, and the temperature inside the battery cell and the external temperature often have a temperature difference of 10-20 degrees, which is not conducive to the high-rate use and cycle life of the battery cell; 2) The tabs are output on the same side, resulting in a small flow area and limited power performance of the energy storage device; 3) During the assembly process, the core and the shell have a certain assembly ratio (mostly the core size is a certain percentage of the internal size of the shell). The core is in an unfixed state inside, which can easily cause the core to shake, and in severe cases, it will cause the connection part to tear.

[0005] Another mainstream structure in existing technology is the cylindrical battery cell. Externally, the cell is cylindrical, with the positive and negative electrodes located on either side. The outer shell is typically stamped or extruded. Internally, the tabs on the core are located on opposite sides, with the positive and negative tabs located at either end. The core is cylindrical, often hollow in the middle. Some products have a support structure in the middle. The tabs are die-cut before winding, and after the core is formed, they are stacked into a dense layer along the guide layer of the current collector for subsequent welding. The cell consists of a single core.

[0006] The disadvantages of this structure in the prior art are: 1) The cross-stacking of the battery cell poles results in inconsistent thickness of the current collector layer, and the uniformity is poor when laser welding is used; 2) The heat dissipation capacity of the battery cell is poor, and the temperature inside the battery cell and the external temperature often have a temperature difference of 10-20 degrees, which is not conducive to the use of the battery cell at a high rate and the cycle life; 3) A few winding cores have a support structure, which mostly supports the winding core. It is not connected to the end plate or the shell. The winding core is fixed close to the busbars on both sides. In a high-intensity environment, it is very easy to cause damage to the welding; 4) The welding of the busbar is not conducive to the expansion of the battery cell. During the expansion process of the battery cell, the current collector will be displaced, and to a certain extent, the welding point will be torn. Summary of the Invention

[0007] In view of this, the present invention aims to provide a battery cell tab lead-out structure to solve at least one of the above-mentioned existing problems.

[0008] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0009] A battery cell tab lead-out structure includes a winding core, a core rod, a positive electrode adapter plate, a negative electrode adapter plate, a positive electrode bus bar and a negative electrode bus bar. The winding core is arranged around the core rod, and the positive electrode at one end of the winding core is connected to the positive electrode adapter plate through the positive electrode bus bar, and the negative electrode at the other end of the winding core is connected to the negative electrode adapter plate through the negative electrode bus bar.

[0010] Furthermore, the winding core is formed by stacking and winding a positive electrode sheet, a negative electrode sheet and a separator, and a positive electrode collector is provided at the end of the positive electrode sheet, and a negative electrode collector is provided at the end of the negative electrode sheet. The positive electrode collector and the negative electrode collector are arranged opposite to each other, the positive electrode collector is connected to the positive electrode bus bar, and the negative electrode collector is connected to the negative electrode bus bar.

[0011] Furthermore, the positive electrode adapter plate and the negative electrode adapter plate respectively include multiple metal plates, and the multiple metal plates are stacked on each other.

[0012] Furthermore, the positive electrode adapter plate and the negative electrode adapter plate have the same structure. The positive electrode adapter plate includes a first compacting plate, and the first compacting plate is connected to the second compacting plate through a soft connection portion. The second compacting plate can be folded relative to the first compacting plate through the soft connection portion, and the first compacting plate and the second compacting plate can be respectively connected to the positive bus bar.

[0013] Furthermore, a shell is provided on the periphery of the winding core, and a positive electrode cover plate assembly and a negative electrode cover plate assembly are respectively provided at both ends of the shell, the positive electrode cover plate assembly is connected to the positive electrode adapter plate, and the negative electrode cover plate assembly is connected to the negative electrode adapter plate.

[0014] Furthermore, a cooling channel is provided on the core rod, and a cooling medium can pass through the cooling channel.

[0015] Furthermore, the core rod is provided with a plurality of cooling channels, and each cooling channel is arranged along the axial direction of the core rod.

[0016] Furthermore, the positive electrode cover plate assembly includes a first plate body and a positive electrode column, wherein the first plate body is connected to the end of the shell, the positive electrode column is connected to the positive electrode adapter, and the outer periphery of the positive electrode column is connected to the first plate body through a first insulating sealing portion;

[0017] Furthermore, the negative electrode cover plate assembly includes a second plate body and a negative electrode column, and the second plate body is connected to the end of the shell, the negative electrode column is connected to the negative electrode adapter plate, and the outer periphery of the negative electrode column is connected to the second plate body through a second insulating sealing portion.

[0018] Furthermore, the first insulating sealing portion and the second insulating sealing portion have the same structure, and the first insulating sealing portion is provided with a rubber pad.

[0019] Furthermore, an explosion-proof valve and a liquid injection port are respectively provided on the first plate body or the second plate body.

[0020] Compared with the prior art, the battery cell tab lead-out structure described in the present invention has the following beneficial effects:

[0021] (1) The utility model discloses a battery cell tab lead-out structure, in which the positive electrode at one end of the winding core is connected to the positive electrode adapter through the positive electrode bus bar, and the negative electrode at the other end of the winding core is connected to the negative electrode adapter through the negative electrode bus bar. The large tabs are led out at both ends of the winding core, which increases the current capacity of the battery cell and effectively improves the adaptability of the battery cell in a high-rate use environment.

[0022] (2) The battery cell tab lead-out structure described in the present invention, by providing a core rod with a cooling channel, can solve the problem of high-rate charging and discharging and high temperature inside the energy storage device during long cycles on the one hand, and can also provide structural strength support to improve the user experience on the other hand.

[0023] (3) The utility model describes a battery cell tab lead-out structure, in which the negative electrode adapter and the positive electrode adapter are respectively provided with soft connection structures. The soft connection design of the adapter effectively improves the assembly difficulty and reduces the processing cost. The stacking number of the positive electrode collector and the negative electrode collector at each position is consistent, which reduces the requirements for welding technology and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 This is a schematic structural diagram of the battery cell according to an embodiment of the present utility model;

[0026] Figure 2 This is a schematic diagram of the explosion structure of the battery cell according to an embodiment of the present utility model;

[0027] Figure 3 This is a cross-sectional schematic diagram of a battery cell according to an embodiment of the present utility model;

[0028] Figure 4 for Figure 3 A partial enlarged view of middle A;

[0029] Figure 5 This is a schematic diagram of a first embodiment of the connection between the first compacting plate, the soft connecting portion and the second compacting plate of the present invention;

[0030] Figure 6 This is a schematic diagram of a second embodiment of the connection between the first compacting plate, the soft connecting portion and the second compacting plate of the present invention;

[0031] Figure 7 This is a schematic diagram of a third embodiment of the connection between the first compacting plate, the soft connecting portion, and the second compacting plate of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of the winding core, core rod and positive electrode adapter according to an embodiment of the present utility model;

[0033] Figure 9 This is a schematic diagram of the structure of the positive electrode sheet, the negative electrode sheet and the separator stacked and wound to form a winding core according to an embodiment of the present invention;

[0034] Figure 10 This is a structural schematic diagram of the positive electrode cover plate assembly and the negative electrode cover plate assembly installed at both ends of the winding core according to an embodiment of the present utility model.

[0035] Description of reference numerals:

[0036] 1-winding core; 11-positive electrode current collector; 12-negative electrode current collector; 2-core rod; 21-cooling channel; 3-positive electrode adapter; 31-first compacting plate; 32-soft connection part; 33-second compacting plate; 4-negative electrode adapter; 5-positive electrode bus bar; 6-negative electrode bus bar; 7-housing; 8-positive electrode cover plate assembly; 81-first plate body; 82-positive electrode column; 9-negative electrode cover plate assembly; 91-second plate body; 92-negative electrode column; 93-explosion-proof valve; 94-liquid injection port. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0039] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0040] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0041] like Figures 1-10 As shown, a battery cell tab lead-out structure includes a winding core 1, a core rod 2, a positive electrode adapter 3, a negative electrode adapter 4, a positive electrode bus 5 and a negative electrode bus 6. The winding core 1 is arranged on the periphery of the core rod 2, and the positive electrode at one end of the winding core 1 is connected to the positive electrode adapter 3 through the positive electrode bus 5, and the negative electrode at the other end of the winding core 1 is connected to the negative electrode adapter 4 through the negative electrode bus 6. The structure of large tabs is led out at both ends of the winding core 1, which increases the current capacity of the battery cell and effectively improves the adaptability of the battery cell in a high-rate usage environment.

[0042] The core 1 is composed of a positive electrode sheet, a negative electrode sheet and a separator stacked and wound, and a positive electrode collector 11 is provided at the end of the positive electrode sheet, and a negative electrode collector 12 is provided at the end of the negative electrode sheet. The positive electrode collector 11 and the negative electrode collector 12 are arranged opposite to each other, the positive electrode collector 11 is connected to the positive electrode bus 5, and the negative electrode collector 12 is connected to the negative electrode bus 6. In this embodiment, the collector ears of the negative electrode collector 12 and the positive electrode collector 11 are exposed in the form of multiple pieces of rectangular foil, and the size information is 2mm≤H2 (exposed length)≤50mm, 10mm≤W1 (exposed width)≤300mm.

[0043] The positive electrode adapter plate 3 and the negative electrode adapter plate 4 each include a plurality of metal sheets, and the plurality of metal sheets are stacked on each other.

[0044] The material of the positive electrode adapter 3 and the negative electrode adapter 4 is a conductive metal material. In this embodiment, the size of the positive electrode adapter 3 and the negative electrode adapter 4 are consistent, and the size information is 100mm≤length≤1000mm; 10mm≤width≤200mm; 0.2mm≤thickness≤5mm. The structural feature is that a single layer of metal sheets is stacked and laminated, and the thickness of the single layer of metal sheets is 0.1mm~1mm. Figure 5-Figure 6 As shown, the positive electrode adapter 3 and the negative electrode adapter 4 have the same structure, including a first compacting plate 31, and the first compacting plate 31 is connected to the second compacting plate 33 through a soft connecting portion 32, and the soft connecting portion 32 can be bent at an angle of 0-180 degrees, so that the second compacting plate 33 can be folded relative to the first compacting plate 31 through the soft connecting portion 32, and the first compacting plate 31 and the second compacting plate 33 can be connected to the positive busbar 5 respectively, and Figure 5 Schematic diagram of a first embodiment of the connection between the first compacting plate 31, the soft connecting portion 32 and the second compacting plate 33; Figure 6 A schematic diagram of a second embodiment of the connection between the first compacting plate 31, the soft connecting portion 32 and the second compacting plate 33; Figure 7 This is a schematic diagram of a third embodiment of the connection between the first compacting plate 31, the soft connecting portion 32 and the second compacting plate 33, so as to meet different product requirements and installation working conditions.

[0045] The outer periphery of the winding core 1 is provided with a shell 7, and the two ends of the shell 7 are provided with a positive cover plate assembly 8 and a negative cover plate assembly 9, the positive cover plate assembly 8 is connected to the positive electrode adapter 3, and the negative cover plate assembly 9 is connected to the negative electrode adapter 4; a cooling channel 21 is provided on the core rod 2, and the cooling medium can pass through the cooling channel 21, and as shown in FIG. Figure 2 As shown, the core rod 2 is provided with multiple cooling channels 21, and each cooling channel 21 is arranged axially along the core rod 2, wherein the core rod 2 is a porous aluminum flat tube structure with dimensions of 2mm≤thickness≤10mm, 10mm≤width≤200mm, and 100mm≤length≤1000mm. The winding core 1 and the shell 7 constitute the battery cell, and the core rod 2 forms a built-in liquid cooling channel for the battery cell. The positive and negative poles are located at both ends, and the outer shape is square with a certain curvature of the R angle. Its dimensions are 100mm≤length≤1000mm, 50mm≤height≤300mm, 10mm≤thickness≤200mm, and 2mm≤R angle curvature≤100mm. The runway design of the battery cell effectively improves the grouping rate.

[0046] like Figure 1 and Figure 2As shown, the positive electrode cover plate assembly 8 includes a first plate 81 and a positive electrode column 82, and the first plate 81 is connected to the end of the housing 7, the positive electrode column 82 is connected to the positive electrode adapter 3, and the outer periphery of the positive electrode column 82 is connected to the first plate 81 via a first insulating seal. The negative electrode cover plate assembly 9 includes a second plate 91 and a negative electrode column 92, and the second plate 91 is connected to the end of the housing 7, the negative electrode column 92 is connected to the negative electrode adapter 4, and the outer periphery of the negative electrode column 92 is connected to the second plate 91 via a second insulating seal. The structures of the first insulating seal and the second insulating seal are the same and both are prior art. In this embodiment, the first insulating seal is a rubber pad, and an explosion-proof valve 93 and a liquid injection port 94 are provided. During implementation, the explosion-proof valve 93 and the liquid injection port 94 can be provided on the first plate 81 or on the second plate 91. In this embodiment, the explosion-proof valve 93 and the liquid injection port 94 are respectively provided on the second plate 91.

[0047] As a preferred embodiment:

[0048] The core 1 includes a positive electrode sheet, a negative electrode sheet and a separator, which are wound on the core rod 2 in a laminated structure of separator-negative electrode sheet-separator-positive electrode sheet. The tabs of the positive electrode sheet and the negative electrode sheet are on opposite sides during the winding process. The structural diagram of the core 1 is shown in FIG. Figure 9 As shown;

[0049] The positive electrode sheet comprises a positive electrode active material coating and a positive electrode current collector 11 layers; the positive electrode current collector 11 layers are aluminum foil, and the aluminum foil tabs are die-cut into a predetermined rectangular size before winding. After winding, each turn is stacked together, located on one side of the winding core 1 and arranged at one end of the core rod 2; the positive electrode active material coating is one or more of lithium iron phosphate, ternary, and nickel-cobalt-manganese lithium;

[0050] The negative electrode sheet comprises a negative electrode active material coating and 12 layers of negative electrode current collectors; the current collector layer is copper foil, and the copper foil tabs are die-cut into a predetermined rectangular size before winding. After winding, each turn is stacked together and located on the other side of the winding core 1 and arranged at one end of the core rod 2; the negative electrode active material coating is graphite, soft carbon, or hard carbon;

[0051] The core rod 2 is a porous flat tube structure with an insulating layer on the surface, which is completely insulated from the positive and negative electrodes. The two ends are led out through the holes of the cover plate for laser welding. During implementation, the core rod 2 is made of aluminum, copper or other high thermal conductivity materials. During installation, the core rod 2 is connected to the positive and negative electrode cover plate substrates, which can provide good strength support.

[0052] The negative busbar 6, the positive busbar 5 and the positive and negative current collectors 12 drawn from the winding core 1 are laser welded respectively. The negative electrode adapter 4, the negative busbar 6 and the negative electrode column are laser welded together. The positive electrode adapter 3, the positive busbar 5 and the positive electrode column are laser welded together. Figure 10As shown; the negative busbar 6 is made of copper and has a rectangular shape; the positive busbar 5 is made of aluminum and has a rectangular shape; the negative electrode adapter 4 is made of copper and has a soft connection structure; the negative electrode adapter 4 is made of aluminum and has a soft connection structure.

[0053] The above-mentioned soft connection is realized by the soft connection part 32, which can be applied to different degrees of bending during the assembly process to meet the assembly connection requirements. The schematic diagram of the adapter bending in different states is shown in FIG. Figure 5-Figure 7 As shown, after the assembly is completed, the tabs of the battery cell are finally led to their respective poles through the current collector, busbar, and adapter, thereby realizing the lead-out of the tabs inside the battery cell and achieving a simple assembly process.

[0054] A battery cell tab lead-out structure achieves the following beneficial effects through structural innovation:

[0055] By providing a core rod 2 with a cooling channel 21 on the core rod 2, on the one hand, the problem of high-rate charging and discharging and high temperature inside the energy storage device during long cycles is solved, and on the other hand, the structural strength is supported to improve the user experience.

[0056] A positive cover assembly 8 and a negative cover assembly 9 are provided at both ends of the outer shell, and the positive cover assembly 8 is connected to the positive current collecting sheet, and the negative cover assembly 9 is connected to the negative current collecting sheet, realizing the structural design of the large pole ear led out from the other end of the winding core 1, increasing the current flow capacity of the battery cell, and effectively improving the adaptability of the battery cell in a high-rate usage environment.

[0057] The negative electrode adapter plate 4 and the positive electrode adapter plate 3 are respectively provided with a soft connection structure. The soft connection design of the adapter plate effectively improves the assembly difficulty and reduces the processing cost. The number of stacking layers of the positive electrode collector and the negative electrode collector at each position is consistent, which reduces the requirements for welding technology and reduces production costs. There is still room for movement after the collector tabs are welded, which is conducive to adapting to the product's liquid absorption expansion and the displacement changes caused by charging and discharging expansion, thereby increasing the product's usage experience.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A battery cell tab lead-out structure, characterized by: The invention comprises a winding core (1), a core rod (2), a positive electrode transfer sheet (3), a negative electrode transfer sheet (4), a positive electrode bus bar (5) and a negative electrode bus bar (6); the winding core (1) is arranged on the periphery of the core rod (2); the positive electrode at one end of the winding core (1) is connected to the positive electrode transfer sheet (3) via the positive electrode bus bar (5); and the negative electrode at the other end of the winding core (1) is connected to the negative electrode transfer sheet (4) via the negative electrode bus bar (6).

2. The battery cell tab lead-out structure according to claim 1, characterized in that: The winding core (1) is formed by stacking and winding a positive electrode sheet, a negative electrode sheet and a separator, and a positive electrode collector (11) is provided at the end of the positive electrode sheet, and a negative electrode collector (12) is provided at the end of the negative electrode sheet. The positive electrode collector (11) and the negative electrode collector (12) are arranged opposite to each other, the positive electrode collector (11) is connected to the positive electrode bus bar (5), and the negative electrode collector (12) is connected to the negative electrode bus bar (6).

3. The battery cell tab lead-out structure according to claim 1, characterized in that: The positive electrode switching plate (3) and the negative electrode switching plate (4) respectively include a plurality of metal sheets, and the plurality of metal sheets are stacked on each other.

4. The battery cell tab lead-out structure according to claim 1, characterized in that: The positive electrode adapter plate (3) and the negative electrode adapter plate (4) have the same structure. The positive electrode adapter plate (3) includes a first compacting plate (31), and the first compacting plate (31) is connected to the second compacting plate (33) via a soft connecting portion (32). The second compacting plate (33) can be folded relative to the first compacting plate (31) via the soft connecting portion (32), and the first compacting plate (31) and the second compacting plate (33) can be respectively connected to the positive electrode busbar (5).

5. The battery cell tab lead-out structure according to claim 1, characterized in that: A shell (7) is sleeved around the outer periphery of the winding core (1), and a positive electrode cover plate assembly (8) and a negative electrode cover plate assembly (9) are respectively provided at both ends of the shell (7), the positive electrode cover plate assembly (8) is connected to the positive electrode adapter plate (3), and the negative electrode cover plate assembly (9) is connected to the negative electrode adapter plate (4).

6. The battery cell tab lead-out structure according to claim 1, characterized in that: A cooling channel (21) is provided on the core rod (2), and a cooling medium can pass through the cooling channel (21).

7. The battery cell tab lead-out structure according to claim 1, characterized in that: A plurality of cooling channels (21) are provided on the core rod (2), and each cooling channel (21) is arranged axially along the core rod (2).

8. The battery cell tab lead-out structure according to claim 1, characterized in that: The positive electrode cover plate assembly (8) includes a first plate body (81) and a positive electrode column (82), wherein the first plate body (81) is connected to the end of the shell (7), the positive electrode column (82) is connected to the positive electrode adapter (3), and the periphery of the positive electrode column (82) is connected to the first plate body (81) through a first insulating sealing portion; The negative electrode cover plate assembly (9) includes a second plate body (91) and a negative electrode column (92), wherein the second plate body (91) is connected to the end of the shell (7), the negative electrode column (92) is connected to the negative electrode adapter (4), and the periphery of the negative electrode column (92) is connected to the second plate body (91) through a second insulating sealing portion.

9. The battery cell tab lead-out structure according to claim 8, characterized in that: The first insulating sealing part and the second insulating sealing part have the same structure, and the first insulating sealing part has a rubber pad.

10. The battery cell tab lead-out structure according to claim 8, characterized in that: An explosion-proof valve (93) and a liquid injection port (94) are respectively provided on the first plate body (81) or the second plate body (91).

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