Cell Hot Pressing Fixture and Hot Pressing Method

Abstract

Embodiments of the present application disclose a cell hot pressing fixture and a hot pressing method. By providing a first adaptive layer on the first pressing plate of the hot press and a second adaptive layer on the second pressing plate, during the hot pressing process, the first adaptive layer undergoes elastic deformation under the combined action of the first pressing plate and the cell body to be hot pressed, and closely adheres to the side of the cell body facing the first pressing plate. The second adaptive layer undergoes elastic deformation under the combined action of the second pressing plate and the cell body to be hot pressed, and closely adheres to the side of the cell body facing the second pressing plate, so that both the body area and the thinned area of the cell body to be hot pressed are subjected to sufficient pressure to ensure the consistency of the hot pressing interface, enabling a complete and effective hot pressing action to be generated in the thinned area, causing the separator on the surface of the thinned area to be subjected to a comprehensive hot pressing force, realizing the complete pressing of the hot pressing interfaces of the body area, the thinned area, and the separator, and overcoming the problem of lithium plating caused by insufficient adhesion between the thinned area and the separator of the stacked cell to be hot pressed under ultra-fast charging conditions.

Description

Technical Field

[0001] This application relates to the technical field of cell hot pressing, and particularly relates to a cell hot pressing jig and a hot pressing method. Background Art

[0002] Cell hot pressing is a conventional process technology. Currently, this process is relatively mature and widely used. In this technology, the upper hot pressing plate and the lower hot pressing plate adopt a rigid body structure, and an aramid insulating paper is usually added between the upper hot pressing plate and the lower hot pressing plate to prevent the surface diaphragm of the cell from adhering to the surfaces of the upper and lower hot pressing rigid bodies.

[0003] The main body of the cell includes a body area and a thinning area. The thickness of the thinning area is less than that of the body area, so that the surface of the cell body is not a plane. Moreover, the size and position of the thinning area are determined by processes such as coating, rolling, slicing, and laminating. The specific position and size of the thinning area have a certain floating range, resulting in the upper hot pressing plate and the lower hot pressing plate being unable to accurately and effectively press the thinning area through a fixed flat plate or a gradient structure, causing a "hot pressing blank area" or local overpressure in the thinning area, and further causing lithium plating problems due to insufficient fitting between the thinning area and the diaphragm. Summary of the Invention

[0004] The embodiments of this application provide a cell hot pressing jig and a hot pressing method, which can solve the lithium plating problem caused by the inability of the hot pressing plate in the existing hot pressing jig to press the thinning area.

[0005] The embodiments of this application provide a cell hot pressing jig for being assembled on a hot press. The hot press includes a first pressing plate and a second pressing plate which are oppositely arranged. The cell hot pressing jig includes: a first adaptive layer disposed on the first pressing plate. The first adaptive layer is configured to be elastically deformed under an external force. The first adaptive layer is used to press against one surface of the cell to be hot pressed under the action of the first pressing plate. The first adaptive layer is elastically deformed and closely adheres to the cell to be hot pressed; and a second adaptive layer disposed on the second pressing plate. The second adaptive layer is configured to be elastically deformed under an external force. The second adaptive layer is used to press against the other surface of the cell to be hot pressed under the action of the second pressing plate. The second adaptive layer is elastically deformed and closely adheres to the cell to be hot pressed.

[0006] Meanwhile, the embodiments of this application also provide a cell hot pressing method, including the following steps:

[0007] Stack the first adaptive layer and the first transfer layer on the first pressing plate of the hot press, and stack the second adaptive layer and the second transfer layer on the second pressing plate of the hot press;

[0008] Place the cell to be hot pressed on the second transfer layer;

[0009] The first adaptive layer and the first transfer layer move towards the to-be-thermocompressed battery cell under the drive of the first pressing plate. The first adaptive layer undergoes elastic deformation under the action of the first pressing plate and the to-be-thermocompressed battery cell. The first transfer layer undergoes bending deformation under the action of the elastic deformation of the first adaptive layer and closely adheres to one surface of the to-be-thermocompressed battery cell. The second adaptive layer undergoes elastic deformation under the action of the second pressing plate and the to-be-thermocompressed battery cell. The second transfer layer undergoes bending deformation under the action of the elastic deformation of the second adaptive layer and closely adheres to the other surface of the to-be-thermocompressed battery cell.

[0010] The beneficial effect of the present application is to provide a battery cell thermocompression jig and a thermocompression method. By providing a first adaptive layer on the first pressing plate of the hot press and a second adaptive layer on the second pressing plate, the first adaptive layer is configured to be elastically deformable under the action of an external force, and the second adaptive layer is configured to be elastically deformable under the action of an external force. Thus, during the thermocompression process, the first adaptive layer can undergo elastic deformation under the combined action of the first pressing plate and the to-be-thermocompressed battery cell, and its deformation amount can adapt to the change in the main body thickness and closely adhere to one side of the to-be-thermocompressed battery cell main body facing the first pressing plate. The second adaptive layer can undergo elastic deformation under the combined action of the second pressing plate and the to-be-thermocompressed battery cell main body, and its deformation amount can adapt to the change in the main body thickness and closely adhere to the other side of the to-be-thermocompressed battery cell main body facing the second pressing plate. Thereby, both the body area and the thinned area of the to-be-thermocompressed battery cell main body are subjected to sufficient pressure to ensure the consistency of the thermocompression interface, enabling a complete and effective thermocompression effect to be generated in the thinned area, enabling the separator on the surface of the thinned area to be subjected to a comprehensive thermocompression force, realizing the complete pressing of the thermocompression interfaces of the body area, the thinned area, and the separator, and overcoming the problem of lithium plating caused by insufficient adhesion between the thinned area and the separator of the stacked to-be-thermocompressed battery cell under ultra-fast charging conditions. Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0012] Figure 1 It is a combined structural schematic diagram of the battery cell thermocompression jig and the to-be-thermocompressed battery cell provided by an embodiment of the present application;

[0013] Figure 1a It is a thermocompression effect diagram of the surface of the battery cell main body after thermocompression of the battery cell by the existing thermocompression jig;

[0014] Figure 1b It is a thermocompression effect diagram of the surface of the battery cell main body after thermocompression of the battery cell by the battery cell thermocompression jig provided by an embodiment of the present application;

[0015] Figure 2 It is a schematic structural diagram of the first angle of the battery cell hot pressing fixture provided by another embodiment of the present application;

[0016] Figure 3 It is a schematic structural diagram of the second angle of the battery cell hot pressing fixture provided by another embodiment of the present application;

[0017] Figure 4 It is a schematic structural diagram of the first angle of the first limiting member in the battery cell hot pressing fixture provided by another embodiment of the present application;

[0018] Figure 5 It is a schematic structural diagram of the second angle of the first limiting member in the battery cell hot pressing fixture provided by another embodiment of the present application;

[0019] Figure 6 It is a schematic structural diagram of the first angle of the second limiting member in the battery cell hot pressing fixture provided by another embodiment of the present application;

[0020] Figure 7 It is a schematic structural diagram of the second angle of the second limiting member in the battery cell hot pressing fixture provided by another embodiment of the present application;

[0021] Figure 8 It is a schematic combined structural diagram of the first angle of the battery cell hot pressing fixture provided by another embodiment of the present application and the battery cell to be hot pressed;

[0022] Figure 9 It is a schematic combined structural diagram of the second angle of the battery cell hot pressing fixture provided by another embodiment of the present application and the battery cell to be hot pressed;

[0023] Figure 10 It is an exploded view of the combination of the battery cell hot pressing fixture provided by another embodiment of the present application and the battery cell to be hot pressed;

[0024] Figure 11 It is a schematic structural diagram of the battery cell hot pressing fixture provided by another embodiment of the present application;

[0025] Figure 12 It is an exploded view of the combination of the battery cell hot pressing fixture provided by another embodiment of the present application and the battery cell to be hot pressed;

[0026] Figure 13 It is a schematic structural diagram of the first angle of the first electromagnet, the first magnetic member and the first magnetic force member in the battery cell hot pressing fixture provided by another embodiment of the present application;

[0027] Figure 14 It is a schematic structural diagram of the second angle of the first electromagnet, the first magnetic member and the first magnetic force member in the battery cell hot pressing fixture provided by another embodiment of the present application;

[0028] Figure 15 It is a schematic structural diagram of a first angle of a second electromagnet, a second magnetic member, and a second magnetic force member in a battery cell hot pressing fixture provided by another embodiment of the present application;

[0029] Figure 16 It is a schematic structural diagram of a second angle of a second electromagnet, a second magnetic member, and a second magnetic force member in a battery cell hot pressing fixture provided by another embodiment of the present application;

[0030] Figure 17 It is a schematic structural diagram of a battery cell;

[0031] Figure 18 is Figure 17 side view of

[0032] Explanation of reference numerals:

[0033] 100, 100’, 100”, battery cell hot pressing fixture, 110a, first adaptive layer, 110b, second adaptive layer, 120a, first transfer layer, 121a, first boundary, 120b, second transfer layer, 121b, second boundary, 130a, first combination layer, 130b, second combination layer, 140a, first limiting member, 140b, second limiting member, 141a, first body, 141b, second body, 142a, first protrusion, 142b, second protrusion, 1421, protrusion unit, 143a, first bending portion, 143b, second bending portion, 144a, first accommodation cavity, 144b, second accommodation cavity, 145a, first mounting hole, 145b, second mounting hole, 146, covering portion, 150a, first lubricating layer, 150b, second lubricating layer, 160a, first electromagnet, 160b, second electromagnet, 170a, first magnetic member, 171a, first groove, 170b, second magnetic member, 171b, second groove, 180a, first magnetic force member, 181a, first card slot, 180b, second magnetic force member, 181b, second card slot;

[0034] 200, battery cell, 210, main body, 210a, first surface, 210b, second surface, 211, body area, 212, thinning area, 213a, first side, 213b, second side, 213c, third side, 213d, fourth side, 214, separator bonding layer, 220, tab;

[0035] 310, first pressing plate, 320, second pressing plate. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; and "inner" and "outer" refer to the outline of the device. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features.

[0037] The cell hot pressing jig and hot pressing method provided by the embodiments of the present application are configured such that a first adaptive layer is provided on the first pressing plate of the hot press, and a second adaptive layer is provided on the second pressing plate. The first adaptive layer is configured to be elastically deformable under an external force, and the second adaptive layer is configured to be elastically deformable under an external force. Thus, during the hot pressing process, the first adaptive layer can be elastically deformed under the combined action of the first pressing plate and the cell to be hot pressed, and its deformation amount can adapt to the change in the thickness of the main body, and closely fit the surface of the cell to be hot pressed facing the first pressing plate. The second adaptive layer can be elastically deformed under the combined action of the second pressing plate and the cell to be hot pressed, and its deformation amount can adapt to the change in the thickness of the main body, and closely fit the surface of the cell to be hot pressed facing the second pressing plate. Thus, both the body area and the thinned area of the cell to be hot pressed are subjected to sufficient pressure to ensure the consistency of the hot pressing interface, so that a complete and effective hot pressing action is generated in the thinned area, and the separator on the surface of the thinned area is subjected to a comprehensive hot pressing force, realizing the complete pressing of the hot pressing interface between the body area, the thinned area and the separator, and overcoming the problem of lithium plating caused by insufficient fitting between the thinned area and the separator of the stacked cell to be hot pressed under ultra-fast charging conditions. As a typical application, the cell hot pressing jig can be used for the hot pressing process of the cell body. In addition, the cell hot pressing jig can also be used for the hot pressing of products with a thickness difference on the surface.

[0038] The structure of the cell hot pressed using the cell hot pressing jig provided by the present application is as shown in Figure 17 and Figure 18As shown, the battery cell 200 includes a main body 210 and an electrode tab 220 disposed at one end of the main body 210. The main body 210 has a first surface 210a and a second surface 210b which are oppositely arranged. At the same time, the main body 210 has a body region 211 and a thinned region 212. The thickness of the thinned region 212 is less than that of the body region 211, forming a thickness difference. The electrode tab 220 is disposed on the end face of the thinned region 212 away from the body region 211. At the same time, the four side edges of the main body 210 are a first side edge 213a, a second side edge 213b, a third side edge 213c, and a fourth side edge 213d. The electrode tab 220 is disposed on the first side edge 213a of the main body 210. The battery cell 200 is a bare battery cell (JR).

[0039] In an embodiment of the present application, referring to Figure 1 , the battery cell hot pressing jig 100 includes: a first adaptive layer 110a and a second adaptive layer 110b. The first adaptive layer 110a and the second adaptive layer 110b are oppositely arranged, and a hot pressing space for hot pressing the battery cell 200 to be hot pressed is defined between the first adaptive layer 110a and the second adaptive layer 110b. Among them, the first adaptive layer 110a is configured to be elastically deformed under the action of an external force, and the second adaptive layer 110b is configured to be elastically deformed under the action of an external force.

[0040] In use, the first adaptive layer 110a is disposed on the side of the first pressing plate (not shown in the figure) of the hot press (not shown in the figure) facing the second pressing plate (not shown in the figure), and the second adaptive layer 110b is disposed on the side of the second pressing plate facing the first pressing plate. The first pressing plate is on the upper side, forming the upper hot pressing plate of the hot press, and the second pressing plate is on the lower side, forming the lower hot pressing plate of the hot press.

[0041] During the hot pressing process, the first pressing plate and the second pressing plate of the hot press move towards each other to hot press the main body 210 of the battery cell 200. Since the thickness of the thinned region 212 of the main body 210 is less than that of the body region 211, there is a gap between the thinned region 212 and the first pressing plate and they cannot be closely attached, resulting in a hot pressing blank area. However, the first adaptive layer 110a undergoes elastic deformation under the combined action of the first pressing plate and the main body 210 of the battery cell 200 (under the action of a high-pressure extrusion force), so that the elastic deformation of the first adaptive layer 110a is non-uniform elastic deformation. The deformation amount of the first adaptive layer 110a can adapt to the thickness change of the main body 210, so that the first adaptive layer 110a is closely attached to the first surface 210a of the main body 210 (that is, the side of the main body 210 facing the first adaptive layer 110a), thereby ensuring that each point of the first surface 210a of the main body 210 receives sufficient hot pressing pressure, ensuring the consistency of the hot pressing interface, and eliminating the hot pressing blank area between the first pressing plate and the thinned region 212.

[0042] Similarly, under the combined action of the second pressing plate and the main body 210 of the battery cell 200 (under the action of high-pressure extrusion force), the second adaptive layer 110b undergoes elastic deformation, such that the elastic deformation of the second adaptive layer 110b is non-uniform elastic deformation. The deformation amount of the second adaptive layer 110b can adapt to the thickness change of the main body 210, enabling the second adaptive layer 110b to closely fit the second surface 210b of the main body 210 (i.e., the side of the main body 210 facing the second adaptive layer 110b). As a result, sufficient hot pressing pressure is applied to each point of the second surface 210b of the main body 210, ensuring the consistency of the hot pressing interface and eliminating the hot pressing blank area between the second pressing plate and the thinned area 212.

[0043] Specifically, the deformation amount of the first adaptive layer 110a in contact with the thinned area 212 is smaller than the deformation amount of the first adaptive layer 110a in contact with the main body area 211, and the deformation amount of the second adaptive layer 110b in contact with the thinned area 212 is smaller than the deformation amount of the second adaptive layer 110b in contact with the main body area 211.

[0044] In addition, referring to Figure 1 , the battery cell hot pressing fixture 100 provided in this embodiment further includes a first transfer layer 120a and a second transfer layer 120b. The first transfer layer 120a is disposed on the side of the first adaptive layer 110a facing the second adaptive layer 110b, and the second transfer layer 120b is disposed on the side of the second adaptive layer 110b facing the first adaptive layer 110a. The first transfer layer 120a is configured to undergo bending deformation under the action of the elastic deformation of the first adaptive layer 110a, and the second transfer layer 120b is configured to undergo bending deformation under the action of the elastic deformation of the second adaptive layer 110b.

[0045] The method of hot pressing the battery cell 200 to be hot pressed using the battery cell hot pressing fixture 100 includes the following steps:

[0046] S100. Stack the first adaptive layer 110a and the first transfer layer 120a on the first pressing plate of the hot press, and stack the second adaptive layer 110b and the second transfer layer 120b on the second pressing plate of the hot press;

[0047] S101. Place the battery cell 200 to be hot pressed on the second transfer layer 120b;

[0048] S103. The first adaptive layer 110a and the first transfer layer 120a move towards the battery cell to be hot-pressed under the drive of the first pressing plate. The first adaptive layer 110a undergoes elastic deformation under the action of the first pressing plate and the battery cell 200 to be hot-pressed. The first transfer layer 120a undergoes bending deformation under the action of the elastic deformation of the first adaptive layer 110a and closely adheres to one surface of the battery cell 200 to be hot-pressed. The second adaptive layer 110b undergoes elastic deformation under the action of the second pressing plate and the battery cell 200 to be hot-pressed. The second transfer layer 120b undergoes bending deformation under the action of the elastic deformation of the second adaptive layer 110b and closely adheres to the other surface of the battery cell 200 to be hot-pressed, thereby hot-pressing the battery cell 200.

[0049] Specifically, during the hot-pressing process, the first transfer layer 120a corresponding to the thinning area 212 undergoes bending deformation under the action of the first adaptive layer 110a to closely adhere to the side of the thinning area 212 facing the first transfer layer 120a. The second transfer layer 120b corresponding to the thinning area 212 undergoes bending deformation under the action of the second adaptive layer 110b to closely adhere to the side of the thinning area 212 facing the second transfer layer 120b. The principle is as follows: The deformation amount of the first adaptive layer 110a in contact with the thinning area 212 is smaller than that of the first adaptive layer 110a in contact with the body area 211. The deformation resistance generated by the elastic deformation of the first adaptive layer 110a can cause the first transfer layer 120a to undergo bending deformation, and the bending deformation of the first transfer layer 120a can match the thickness change of the thinning area 212 of the main body 210. Similarly, the deformation amount of the second adaptive layer 110b in contact with the thinning area 212 is smaller than that of the second adaptive layer 110b in contact with the body area 211. The deformation resistance generated by the elastic deformation of the second adaptive layer 110b can cause the second transfer layer 120b to undergo bending deformation, and the bending deformation of the second transfer layer 120b can match the thickness change of the thinning area 212 of the main body 210.

[0050] The first transfer layer 120a and the second transfer layer 120b have the same functions: First, they adjust the stress condition of the thinning area 212, so that the compensation pressure generated by the first adaptive layer 110a and the second adaptive layer 110b on the thinning area 212 can be evenly and smoothly applied to the thinning area 212. Second, they restrict the first adaptive layer 110a and the second adaptive layer 110b so that their deformation will not affect the boundary of the main body 210 and prevent stress concentration at the corner parts of the main body 210.

[0051] In addition, the first transfer layer 120a is arranged to extend beyond the boundary of the main body 210 of the battery cell 200 on one side of the thinned area 212 of the main body 210. That is, the first transfer layer 120a has a plurality of first boundaries 121a, and the first boundary 121a corresponding to one end of the tab 220 provided on the main body 210 extends beyond the boundary of the first side 213a of the main body 210 where the tab 220 is provided. The extended distance is determined according to the performance of the first transfer layer 120a. The basic principle is that under the hot pressing pressure condition, the first transfer layer 120a undergoes elastic deformation and bends on one side of the thinned area 212 to form a smooth arc-shaped profile in the area of the thinned area 212, and the size specification of this profile coincides with the theoretically calculated size specification of the thinned area 212.

[0052] In addition, the other first boundaries 121a of the first transfer layer 120a may extend beyond the boundaries of the adjacent second side 213b, third side 213c, and fourth side 213d on the main body 210, or be flush with the boundaries of the adjacent second side 213b, third side 213c, and fourth side 213d. However, when extending beyond the boundaries of the second side 213b, third side 213c, and fourth side 213d, it is necessary to ensure that the extended part of the first boundary 121a does not undergo bending deformation. If bending deformation occurs, the extended amount beyond the boundaries of the second side 213b, third side 213c, and fourth side 213d needs to be reduced.

[0053] In this embodiment, referring to Figure 1 , the first boundaries 121a of the first transfer layer 120a all extend beyond the adjacent sides of the main body 210. The boundary of the first adaptive layer 110a is flush with the boundary of the first transfer layer 120a. In other implementation manners, the boundary of the first adaptive layer 110a is located inside the boundary of the first transfer layer 120a, but the boundary of the first adaptive layer 110a should be flush with or extend beyond the adjacent sides of the main body 210. However, the boundary of the first adaptive layer 110a corresponding to the first side 213a of the main body 210 where the tab 220 is provided needs to extend beyond the first side 213a.

[0054] The second transfer layer 120b is arranged to extend beyond the boundary of the main body 210 of the battery cell 200 on one side of the thinned area 212 of the main body 210. That is, the second transfer layer 120b has a plurality of second boundaries 121b, and the second boundary 121b corresponding to one end of the tab 220 provided on the main body 210 extends beyond the boundary of the first side 213a of the main body 210 where the tab 220 is provided. The extended distance is determined according to the performance of the second transfer layer 120b. The basic principle is that under the hot pressing pressure condition, the second transfer layer 120b undergoes elastic deformation and bends on one side of the thinned area 212 to form a smooth arc-shaped profile in the area of the thinned area 212, and the size specification of this profile coincides with the theoretically calculated size specification of the thinned area 212.

[0055] The second boundary 121b of the second transfer layer 120b can extend beyond the boundaries of the adjacent second side 213b, third side 213c, and fourth side 213d on the main body 210, or be flush with the boundaries of the adjacent second side 213b, third side 213c, and fourth side 213d. However, when extending beyond the boundaries of the second side 213b, third side 213c, and fourth side 213d, it is necessary to ensure that the extended part of the second boundary 121b does not bend and deform. If bending and deformation occur, the amount of extension beyond the boundaries of the second side 213b, third side 213c, and fourth side 213d needs to be reduced.

[0056] In this embodiment, referring to Figure 1 , the second boundary 121b of the second transfer layer 120b extends beyond the adjacent sides of the main body 210. The boundary of the second adaptive layer 110b is flush with the boundary of the second transfer layer 120b. In other implementation manners, the boundary of the second adaptive layer 110b is located inside the boundary of the second transfer layer 120b, but the boundary of the second adaptive layer 110b should be flush with or extend beyond the adjacent sides of the main body 210. However, the boundary of the second adaptive layer 110b corresponding to the first side 213a where the main body 210 is provided with the tab 220 needs to extend beyond the first side 213a.

[0057] Among them, the first adaptive layer 110a and the second adaptive layer 110b are made of the same material, which is a material with high voltage resistance, high voltage elasticity, heat resistance (200 °C), and good heat transfer performance. In this embodiment, the first adaptive layer 110a and the second adaptive layer 110b can respectively adopt heat-conducting silica gel. In other implementation manners, they can be replaced with other specifications of heat-conducting silica gel with a high elastic modulus, or other structural materials that can generate a large elastic deformation resistance, or a combination of structural materials with the same elastic function.

[0058] The first transfer layer 120a and the second transfer layer 120b are made of the same material, which is a material with good bendability, fatigue resistance, heat resistance, high voltage resistance, and does not deform under long-term multiple hot pressing and local cyclic bending conditions. In this embodiment, the first transfer layer 120a and the second transfer layer 120b respectively adopt spring steel sheets. In other implementation manners, spring steel materials with different performances can be selected according to the service life requirements, or other materials with this function.

[0059] The purpose of hot pressing the surface of the main body 210 of the battery cell 200 using the battery cell hot pressing fixture 100 provided in this embodiment is to make the separator adhesive (PVDF) on the surface of the main body 210 evenly distributed to form a separator bonding layer 214, so that the surface of the main body 210 is joined to the electrode sheet (not shown in the figure). The bonding effect of the hot pressing interface in the thinning area 212 is made to be consistent with that of the body area 211. The separator bonding layer 214 can be evenly bonded to the edge of the thinning area 212 (the junction of the ceramic coating and the material area), eliminating the "hot pressing blank area" of the main body 210. In addition, according to needs, the battery cell hot pressing fixture 100 can form slight indentations in the top area of the negative electrode sheet (the area where the thinning area 212 is located) by adjusting the specifications of the first adaptive layer 110a, the second adaptive layer 110b, the first transfer layer 120a, and the second transfer layer 120b. These indentations are consistent with the indentations on the side and bottom overhang areas of the battery cell body area 211.

[0060] Among them, in existing battery cells, whether they are wound battery cells or laminated battery cells, there are thinning areas. From the perspective of the finished battery cell, for battery cells manufactured under conventional hot pressing conditions, due to the thickness difference between the thinning area and the body area, the hot pressing is incomplete, resulting in a relatively fluffy structural state in the thinning area. The appearance contour of the thinning area is in an approximately parallel state with the body area, and the body area and the thinning area are in a stepped shape, with no obvious distinction. This can be regarded as a form of the product characteristics of a battery cell with a thinning area. However, in fact, this structure and characteristics are not what the designer wants, but a compromise due to the limitations of the existing hot pressing process.

[0061] Specifically, referring to Figure 1a , Figure 1a is the hot pressing effect diagram of the surface of the main body 210 of the battery cell 200 after hot pressing with an existing hot pressing fixture. The appearance contour of the thinning area 212 of the main body 210 of this existing battery cell 200 is in an approximately parallel state with 211, with no obvious distinction. This structure results in a certain range of "hot pressing blank area" in the top thinning area 212 region. In this area, the distribution of the separator bonding layer 214 (appearing as visible white spots to the naked eye) is significantly less than that in the body area 211, showing an uneven serrated distribution and being unable to effectively bond the electrode sheet.

[0062] While referring to Figure 1b , using the battery cell hot pressing fixture 100 provided in this embodiment to hot press the surface of the main body 210 of the battery cell 200 as shown in Figure 17 and Figure 18 , as shown in Figure 18As shown, the overall contour feature of the thinning area 212 within the main body 210 is an arc-shaped structure that smoothly extends from the main body area 211. Specifically, in this embodiment, the thinning area 212 extends from the main body area 211 to form an arc surface. After hot pressing the main body 210, the "hot pressing blank area" is eliminated, and the diaphragm adhesive layer 214 is evenly distributed on the entire surface of the main body 210. In the area of the top thinning area 212, the diaphragm adhesive layer 214 can effectively bond the electrode sheet and forms a neat boundary with the electrode sheet Overhang as the boundary. Just looking at the structural performance of the battery cell product, using the structure of the main body 210 as shown in Figure 18 In the structure of such a main body 210, the thinning area 212 and the diaphragm adhesive layer 214 are in close contact.

[0063] In another embodiment of the present application, referring to Figures 2 to 10 , the battery cell hot pressing jig 100' includes: a first combined layer 130a, a second combined layer 130b, a first limiting member 140a, and a second limiting member 140b. Among them, the first combined layer 130a is formed by laminating a first adaptive layer 110a and a first transfer layer 120a, and the second combined layer 130b is formed by laminating a second adaptive layer 110b and a second transfer layer 120b. The first combined layer 130a is closely attached to the first pressing plate of the hot press through the first limiting member 140a, and the second combined layer 130b is closely attached to the second pressing plate of the hot press through the second limiting member 140b.

[0064] Referring to Figures 2 to 5 and Figures 8 to 10, the first limiting member 140a includes a first body 141a, a first protruding portion 142a, and a first bending portion 143a. The first body 141a has a first accommodation cavity 144a for accommodating the first combined layer 130a (i.e., the first adaptive layer 110a and the first transfer layer 120a). One side of the first body 141a is provided with a first opening (not shown in the figure) communicating with the inner side of the first accommodation cavity 144a, so that the first body 141a forms a concave frame structure. The orientation of the first opening corresponds to one end of the tab 220 provided on the main body 210, and the first combined layer 130a extends into the inner side of the first accommodation cavity 144a through the first opening. The first protruding portion 142a protrudes from the surface of the first body 141a facing the second limiting member 140b. The first protruding portion 142a is arranged along the circumference of the first accommodation cavity 144a and surrounds the first accommodation cavity 144a. The side of the first protruding portion 142a away from the first body 141a is bent inward to form a first bending portion 143a. The first bending portion 143a is used to support the first adaptive layer 110a and the first transfer layer 120a. The first bending portion 143a is parallel to the plane where the first body 141a is located, and the first bending portion 143a is perpendicular to the connected first protruding portion 142a, forming an L-shaped cross-sectional structure. The first protruding portion 142a and the first bending portion 143a cooperate to form a support for the first adaptive layer 110a and the first transfer layer 120a in the first accommodation cavity 144a. In this embodiment, the depth of the first accommodation cavity 144a is the same as the thickness of the first combined layer 130a. The depth of the first accommodation cavity 144a = the thickness of the first limiting member 140a + the width of the first protruding portion 142a. Among them, the first protruding portion 142a is a rib.

[0065] In addition, referring to Figure 8 and Figure 9 , the boundary of the first combined layer 130a extends beyond the adjacent side edges of the main body 210. Among them, for the boundaries of the first combined layer 130a extending beyond the second side edge 213b, the third side edge 213c, and the fourth side edge 213d of the main body 210, the width of the extended part is the same as the width of the first bending portion 143a. During the hot pressing process, the end of the first bending portion 143a away from the first protruding portion 142a contacts the side wall of the main body 210, realizing the positioning and limiting of the main body 210 and ensuring the stability of the battery cell 200 during the hot pressing process.

[0066] Furthermore, referring to Figures 2 to 5, the first body 141a is U-shaped, and a plurality of first mounting holes 145a are spaced apart on the first body 141a to achieve the detachable assembly of the first limiting member 140a and the first pressing plate. Specifically, the first limiting member 140a can be assembled on the first pressing plate by means of screw fastening to achieve the close fit of the first composite layer 130a and the first pressing plate, ensuring the heat transfer efficiency. The plurality of first mounting holes 145a are arranged at intervals along the circumferential direction of the first limiting member 140a for corner strengthening. Among them, a first mounting hole 145a is arranged at each corner of the first limiting member 140a to prevent the first composite layer 130a from exerting a large force on the first limiting member 140a during long-term use, resulting in corner loosening or opening.

[0067] Referring to Figures 2 to 3 and Figures 6 to 10 , the second limiting member 140b includes a second body 141b, a second protruding portion 142b, and a second bending portion 143b. The second body 141b has a second accommodating cavity 144b for accommodating the second composite layer 130b (i.e., the second adaptive layer 110b and the second transfer layer 120b). A second opening (not shown in the figure) communicating with the inner side of the second accommodating cavity 144b is provided on one side of the second body 141b, so that the second body 141b forms a concave frame structure. The orientation of the second opening corresponds to one end of the tab 220 provided on the main body 210. The second composite layer 130b extends into the inner side of the second limiting member 140b through the second opening. Specifically, the second protruding portion 142b protrudes from the surface of the second body 141b facing the first limiting member 140a. The second protruding portion 142b is arranged along the circumference of the second accommodating cavity 144b and surrounds the second accommodating cavity 144b. The second protruding portion 142b includes a plurality of protruding units 1421 connected in sequence. In this embodiment, the second protruding portion 142b includes three protruding units 1421 connected in sequence. The three protruding units 1421 are connected in sequence to form a concave shape. The ends of two adjacent protruding units 1421 among the three protruding units 1421 are bent inward to form the second bending portion 143b, and the other protruding unit 1421 is not bent. The second bending portion 143b is parallel to the plane where the second body 141b is located, and the second bending portion 143b is perpendicular to the connected protruding unit 1421, forming an L-shaped cross-sectional structure. The protruding unit 1421 and the second bending portion 143b cooperate to form a restriction and limit on the second adaptive layer 110b and the second transfer layer 120b in the second accommodating cavity 144b. In this embodiment, the depth of the second accommodating cavity 144b is the same as the thickness of the second composite layer 130b, and the depth of the second accommodating cavity 144b = the thickness of the second body 141b + the width of the second protruding portion 142b. Among them, the protruding unit 1421 is a rib.

[0068] In addition, referring to Figure 8 andFigure 9 , the boundary of the second combined layer 130b extends beyond the adjacent side edges of the main body 210. Among them, the boundaries of the second combined layer 130b that extend beyond the second side edge 213b, the third side edge 213c, and the fourth side edge 213d of the main body 210 have the same width as the width of the second bending portion 143b. During the hot pressing process, the end of the second bending portion 143b away from the second protruding portion 142b contacts the side wall of the main body 210, realizing the positioning and limiting of the main body 210 and ensuring the stability of the battery cell 200 during the hot pressing process.

[0069] In addition, referring to Figures 6 to 10 , the second main body 141b is U-shaped, and a plurality of second mounting holes 145b are spaced apart on the second main body 141b of the second limiting member 140b to realize the detachable assembly of the second limiting member 140b and the second pressing plate. Specifically, the second limiting member 140b can be assembled on the second pressing plate by means of screw fastening to realize the close fitting of the second combined layer 130b and the second pressing plate, ensuring the heat transfer efficiency. The plurality of second mounting holes 145b are arranged at intervals along the circumferential direction of the second limiting member 140b to strengthen the corner positions. Among them, one second mounting hole 145b is arranged at each corner of the second limiting member 140b to prevent the second combined layer 130b from causing a large acting force on the second limiting member 140b during long-term use and resulting in corner loosening or opening.

[0070] In addition, a covering portion 146 is provided at one end of the second bending portion 143b away from the protruding unit 1421 it is connected to. The covering portion 146 is arranged along the circumferential direction of the second main body 141b to form an L-shaped cross-section and surrounds part of the second accommodating cavity 144b; during the hot pressing process, the covering portion 146 fits with the side edge of the main body 210. Specifically, referring to Figure 8 and Figure 9 , the covering portion 146 fits with the third side edge 213c and the fourth side edge 213d of the main body 210. The second limiting member 140b is designed in this way for three purposes: one of the three protruding units 1421 that form the second protruding portion 142b is not bent, which is convenient for the placement and positioning of the battery cell 200 during the hot pressing process and reduces the risk of collision; the second is to provide second bending portions 143b on the other two connected protruding units 1421 and a covering portion 146 on the second bending portion 143b for limiting the main body 210 of the battery cell 200, serving the purpose of preventing misplacement; the third is to refer to Figure 7 , a second bending portion 143b is provided at the intersection of the protruding units 1421 connected to the protruding unit 1421 without a bending portion, and triaxial limiting of the second combined layer 130b is realized at this position to prevent its position movement during the hot pressing process.

[0071] Among them, the widths of the first limiting member 140a and the second limiting member 140b are designed to match the width of the battery cell 200. The design principle is that the open ends of the first limiting member 140a and the second limiting member 140b will not exceed the boundary of the first side 213a where the tab 220 is provided on the main body 210 on the premise of ensuring the limiting and fixing functions. The design purpose is to selectively limit the first combined layer 130a and the second combined layer 130b, so that the first combined layer 130a and the second combined layer 130b corresponding to the thinning area 212 at the top of the battery cell can flexibly generate compensatory deformation.

[0072] In addition, the corners of the inner peripheral walls of the first limiting member 140a and the second limiting member 140b in contact with the first combined layer 130a, the second combined layer 130b and the side of the main body 210 of the battery cell 200 are provided with rounded corners to prevent damage to the first combined layer 130a, the second combined layer 130b and the main body 210. The first limiting member 140a and the second limiting member 140b can be made of steel materials by sheet metal or casting processing methods, and some chamfers in the corner areas can be appropriately adjusted according to different processing methods.

[0073] Since the first combined layer 130a in this embodiment is formed by laminating the first adaptive layer 110a and the first transfer layer 120a in the foregoing embodiment, and the second combined layer 130b is formed by laminating the second adaptive layer 110b and the second transfer layer 120b in the foregoing embodiment, the effect of the battery cell hot pressing jig 100' on the main body 210 of the battery cell 200 after hot pressing can be referred to Figure 1b .

[0074] In another embodiment of the present application, referring to Figures 11 to 16 , the battery cell hot pressing jig 100” includes: a first adaptive layer 110a, a second adaptive layer 110b, a first lubricating layer 150a, a second lubricating layer 150b, a first electromagnet 160a, a second electromagnet 160b, a first magnetic member 170a, a second magnetic member 170b, a first magnetic force member 180a and a second magnetic force member 180b.

[0075] Referring to Figures 11 to 12, the first adaptive layer 110a and the second adaptive layer 110b are arranged opposite to each other. The first lubricating layer 150a is stacked on one side of the first adaptive layer 110a facing the second adaptive layer 110b, and the second lubricating layer 150b is stacked on one side of the second adaptive layer 110b facing the first adaptive layer 110a, so as to define a hot-pressing space between the first lubricating layer 150a and the second lubricating layer 150b for hot-pressing the battery cell 200 to be hot-pressed. The first lubricating layer 150a is configured to closely fit with the first surface 210a of the main body 210 of the battery cell 200 to be hot-pressed (i.e., the surface of the main body 210 facing the first adaptive layer 110a) under the action of the elastic deformation of the first adaptive layer 110a during the hot-pressing process. The second lubricating layer 150b is configured to closely fit with the second surface 210b of the main body 210 of the battery cell 200 to be hot-pressed (i.e., the surface of the main body 210 facing the second adaptive layer 110b) under the action of the elastic deformation of the second adaptive layer 110b during the hot-pressing process.

[0076] The main functions of the first lubricating layer 150a and the second lubricating layer 150b are to physically isolate the first adaptive layer 110a and the second adaptive layer 110b from the battery cell 200, eliminate the stretching and extrusion effects of the frictional force of the elastic deformation of the first adaptive layer 110a and the second adaptive layer 110b on the diaphragm bonding layer on the surface of the main body 210 of the battery cell 200, and do not affect the acting force of the first adaptive layer 110a and the second adaptive layer 110b on the main body 210 of the battery cell 200, so as to achieve effective pressing with the surface of the thinning area 212 and not damage the diaphragm bonding layer and the pole piece on the surface of the main body 210 of the battery cell 200. The first lubricating layer 150a and the second lubricating layer 150b can keep the contact part with the surface of the main body 210 of the battery cell 200 flat and intact during the elastic deformation process of the first adaptive layer 110a and the second adaptive layer 110b, without deformation or displacement in position.

[0077] In addition, referring to Figures 11 to 14 , a first electromagnet 160a is inserted on the first pressure plate 310 of the hot press. A first magnetic member 170a that penetrates the first adaptive layer 110a and matches the first electromagnet 160a is arranged on the first adaptive layer 110a. A first magnetic force member 180a that penetrates the first lubricating layer 150a and matches the first electromagnet 160a is arranged on the first lubricating layer 150a. A second electromagnet 160b is inserted on the second pressure plate 320 of the hot press. A second magnetic member 170b that penetrates the second adaptive layer 110b and matches the second electromagnet 160b is arranged on the second adaptive layer 110b. A second magnetic force member 180b that penetrates the second lubricating layer 150b and matches the second electromagnet 160b is arranged on the second lubricating layer 150b.

[0078] The functions of the first electromagnet 160a, the first magnetic member 170a, and the first magnetic force member 180a are to connect the first adaptive layer 110a to the first pressing plate 310, and can adjust or change the degree of connection between the two according to the progress of the hot pressing process, so as to cooperate with the adaptive hot pressing. The functions of the second electromagnet 160b, the second magnetic member 170b, and the second magnetic force member 180b are to connect the second adaptive layer 110b to the second pressing plate 320, and can adjust or change the degree of connection between the two according to the progress of the hot pressing process, so as to cooperate with the adaptive hot pressing.

[0079] Specifically, the method for hot pressing the battery cell 200 by the battery cell hot pressing jig 100” provided in this embodiment is as follows:

[0080] Before hot pressing (including before the start and after the end of hot pressing), the first electromagnet 160a is energized, and the first electromagnet 160a generates a magnetic force to attract the first magnetic member 170a and the first magnetic force member 180a, so that the first electromagnet 160a, the first magnetic member 170a, and the first magnetic force member 180a are connected in sequence, thereby making the first adaptive layer 110a, the first lubricating layer 150a closely fit with the first pressing plate 310. The second electromagnet 160b is energized, and the second electromagnet 160b generates a magnetic force to attract the second magnetic member 170b and the second magnetic force member 180b, so that the second electromagnet 160b, the second magnetic member 170b, and the second magnetic force member 180b are connected in sequence, thereby making the second adaptive layer 110b, the second lubricating layer 150b closely fit with the second pressing plate 320.

[0081] When the hot pressing starts and during the hot pressing process, the first electromagnet 160a is de-energized, and the first electromagnet 160a loses its magnetic force, releasing the attraction on the first magnetic member 170a and the first magnetic force member 180a, so that the first adaptive layer 110a and the first lubricating layer 150a are released from the first pressing plate 310, and under the action of the first pressing plate 310, the first surface 210a of the main body 210 of the battery cell 200 is hot pressed. At the same time, the second electromagnet 160b is de-energized, and the second electromagnet 160b loses its magnetic force, releasing the attraction on the second magnetic member 170b and the second magnetic force member 180b, so that the second adaptive layer 110b and the second lubricating layer 150b are released from the second pressing plate 320, and under the action of the second pressing plate 320, the second surface 210b of the main body 210 of the battery cell 200 is hot pressed.

[0082] Specifically, it includes the following steps:

[0083] S101a. Before hot pressing starts, energize the first electromagnet 160a. The first electromagnet 160a magnetically attracts the first magnetic member 170a and the first magnetic force member 180a, and magnetically adsorbs the first adaptive layer 110a and the first lubricating layer 150a to the first pressing plate 310. Energize the second electromagnet 160b. The second electromagnet 120b magnetically attracts the second magnetic member 170b and the second magnetic force member 180b, and magnetically adsorbs the second adaptive layer 110b and the second lubricating layer 150b to the second pressing plate 320.

[0084] S101b. Place the battery cell 200 to be hot pressed on the second lubricating layer 150b.

[0085] S101c. When hot pressing starts, cut off the power supply of the first electromagnet 160a to release the magnetic adsorption of the first adaptive layer 110a and the first lubricating layer 150a. Cut off the power supply of the second electromagnet 160b to release the magnetic adsorption of the second adaptive layer 110b and the second lubricating layer 150b.

[0086] S101d. Driven by the first pressing plate 310, the first adaptive layer 110a and the first lubricating layer 150a move towards the battery cell 200 to be hot pressed. The first adaptive layer 110a undergoes elastic deformation under the action of the first pressing plate 310 and the battery cell 200 to be hot pressed. The first lubricating layer 150a is in close contact with one surface of the battery cell 200 to be hot pressed under the action of the elastic deformation of the first adaptive layer 110a. The second adaptive layer 110b undergoes elastic deformation under the action of the second pressing plate 320 and the battery cell 200 to be hot pressed. The second lubricating layer 150b is in close contact with the other surface of the battery cell 200 to be hot pressed under the action of the elastic deformation of the second adaptive layer 110b.

[0087] S101e. When hot pressing ends, energize the first electromagnet 160a. The first electromagnet 160a magnetically attracts the first magnetic member 170a and the first magnetic force member 180a, and magnetically adsorbs the first adaptive layer 110a and the first lubricating layer 150a to the first pressing plate 310. Energize the second electromagnet 160b. The second electromagnet 160b magnetically attracts the second magnetic member 170b and the second magnetic force member 180b, and adsorbs the second adaptive layer 110b and the second lubricating layer 150b to the second pressing plate 320.

[0088] In other implementation manners, the cooperation mode of an air pipe and a suction cup can also be adopted, that is, replace the electromagnet with an air pipe, set the suction cup on the adaptive layer and the lubricating layer, the air pipe evacuates air to form negative pressure, attracts the suction cup to drive the adaptive layer and the lubricating layer to fit with the pressing plate, and the air pipe ventilates, and the pressing plate releases the adaptive layer and the lubricating layer.

[0089] Among them, the first lubricating layer 150a can be separately disposed on the side of the first adaptive layer 110a facing the second adaptive layer 110b, or can be used as a lubricating surface or lubricating layer, and exist in a physical or chemical manner on the side of the first adaptive layer 110a facing the second adaptive layer 110b, so as to keep the diaphragm adhesive layer (PVDF) formed on the first surface 210a of the main body 210 of the battery cell 200 flat and not damage the diaphragm adhesive layer on the first surface 210a of the main body 210.

[0090] In addition, referring to Figure 11 and Figure 12 , the boundary of the first adaptive layer 110a extends beyond the adjacent sides of the main body 210 of the battery cell 200 to be hot-pressed, and the boundary of the first adaptive layer 110a is located inside the adjacent boundary of the first pressing plate 310. The first magnetic member 170a is disposed on the first adaptive layer 110a extending beyond the adjacent sides of the main body 210. The boundary of the first lubricating layer 150a extends beyond the adjacent sides of the main body 210 of the battery cell 200 to be hot-pressed, and the first magnetic force member 180a is disposed on the first lubricating layer 150a extending beyond the adjacent sides of the main body 210, so that the first lubricating layer 150a and the first adaptive layer 110a are closely and seamlessly attached to the first pressing plate 310.

[0091] The boundary of the second adaptive layer 110b extends beyond the adjacent sides of the main body 210 of the battery cell 200 to be hot-pressed, and the boundary of the second adaptive layer 110b is located inside the adjacent boundary of the second pressing plate 320. The second magnetic member 170b is disposed on the second adaptive layer 110b extending beyond the adjacent sides of the main body 210. The boundary of the second lubricating layer 150b extends beyond the adjacent sides of the main body 210 of the battery cell 200 to be hot-pressed, and the second magnetic force member 180b is disposed on the second lubricating layer 150b extending beyond the adjacent sides of the main body 210, so that the second lubricating layer 150b and the second adaptive layer 110b are closely and seamlessly attached to the second pressing plate 320.

[0092] In addition, referring to Figure 11 and Figure 12 , the number of the first electromagnets 160a is four, which are distributed at the four corners of the first pressing plate 310. Correspondingly, the number of the first magnetic members 170a is four, which are distributed at the four corners of the first adaptive layer 110a, and the number of the first magnetic force members 180a is four, which are distributed at the four corners of the first lubricating layer 150a. Similarly, the number of the second electromagnets 160b is four, which are distributed at the four corners of the second pressing plate 320. Correspondingly, the number of the second magnetic members 170b is four, which are distributed at the four corners of the second adaptive layer 110b, and the number of the second magnetic force members 180b is four, which are distributed at the four corners of the second lubricating layer 150b.

[0093] In addition, referring toFigures 13 to 14 The first electromagnet 160a and the first magnetic member 170a are nested and connected. The first magnetic member 170a and the first magnetic force member 180a are nested and connected. A groove matching the first electromagnet 160a is provided at one end of the first magnetic member 170a facing the first electromagnet 160a. A protrusion is provided at one end of the first magnetic member 170a facing the first magnetic force member 180a. A groove matching the protrusion of the first magnetic member 170a is formed at one end of the first magnetic force member 180a facing the first magnetic member 170a, so as to realize the sequential nested connection among the first electromagnet 160a, the first magnetic member 170a, and the first magnetic force member 180a.

[0094] A first groove 171a is formed on the outer wall of the first magnetic member 170a along the circumferential direction of the first magnetic member 170a. The first magnetic member 170a is clamped with the first adaptive layer 110a through the first groove 171a to drive the first adaptive layer 110a to move. A first card slot 181a is formed on the outer wall of the first magnetic force member 180a along the circumferential direction of the first magnetic force member 180a. The first magnetic force member 180a is clamped with the first lubricating layer 150a through the first card slot 181a to drive the first lubricating layer 150a to move.

[0095] Refer to Figures 15 to 16 The second electromagnet 160b and the second magnetic member 170b are nested and connected. The second magnetic member 170b and the second magnetic force member 180b are nested and connected. The second magnetic member 170b and the second magnetic force member 180b are nested and connected. A groove matching the second electromagnet 160b is provided at one end of the second magnetic member 170b facing the second electromagnet 160b. A protrusion is provided at one end of the second magnetic member 170b facing the second magnetic force member 180b. A groove matching the protrusion of the second magnetic member 170b is formed at one end of the second magnetic force member 180b facing the second magnetic member 170b, so as to realize the sequential nested connection among the second electromagnet 160b, the second magnetic member 170b, and the second magnetic force member 180b.

[0096] Among them, the nesting method can be trapezoidal nesting or conical nesting. It can play a positioning role to ensure that after each hot pressing is completed, the first adaptive layer 110a and the second adaptive layer 110b return to their original positions, and the first lubricating layer 150a and the second lubricating layer 150b are also flattened.

[0097] On the outer wall of the second magnetic member 170b, a second groove 171b is formed along the circumferential direction of the second magnetic member 170b. The second magnetic member 170b is clamped with the second adaptive layer 110b through the second groove 171b to drive the second adaptive layer 110b to move. On the outer wall of the second magnetic force member 180b, a second clamping groove 181b is formed along the circumferential direction of the second magnetic force member 180b. The second magnetic force member 180b is clamped with the second lubricating layer 150b through the second clamping groove 181b to drive the second lubricating layer 150b to move.

[0098] In this embodiment, the first electromagnet 160a and the second electromagnet 160b are respectively electromagnets. The first magnetic member 170a, the second magnetic member 170b, the first magnetic force member 180a, and the second magnetic force member 180b are respectively I-shaped steel pads.

[0099] In addition, in this embodiment, the thickness difference between the body area 211 and the thinned area 212 of the main body 210 of the battery cell 200 to be hot-pressed is less than one-half of the deformation amount of the first adaptive layer 110a in contact with the body area 211, so as to ensure that the force on the thinnest area of the thinned area 212 is not less than one-half of the body area 211. Similarly, the thickness difference between the body area 211 and the thinned area 212 of the main body 210 of the battery cell 200 to be hot-pressed is less than one-half of the deformation amount of the second adaptive layer 110b in contact with the body area 211, so as to ensure that the force on the thinnest area of the thinned area 212 is not less than one-half of the body area 211.

[0100] Since the structural dimensions of the thinned areas of different stacked battery cells are not exactly the same, the mechanical properties and structural dimensions (mainly the thickness) of the first adaptive layer 110a and the second adaptive layer 110b can be designed according to the structural dimensions of the thinned areas, so as to enable the thinned area to obtain an appropriate hot-pressing pressure. Therefore, in other implementation manners, the thickness difference between the body area 211 and the thinned area 212 of the main body 210 of the battery cell 200 to be hot-pressed is less than one-fourth of the deformation amount of the first adaptive layer 110a in contact with the body area 211, or the thickness difference between the body area 211 and the thinned area 212 of the main body 210 of the battery cell 200 to be hot-pressed is less than one-third of the deformation amount of the first adaptive layer 110a in contact with the body area 211.

[0101] The thickness difference between the body area 211 and the thinned area 212 of the main body 210 of the battery cell 200 to be hot-pressed is less than one-fourth of the deformation amount of the second adaptive layer 110b in contact with the body area 211, or the thickness difference between the body area 211 and the thinned area 212 of the main body 210 of the battery cell 200 to be hot-pressed is less than one-third of the deformation amount of the second adaptive layer 110b in contact with the body area 211.

[0102] The materials of the first adaptive layer 110a and the second adaptive layer 110b in this embodiment are the same, which are materials with high voltage resistance, high voltage elasticity, heat resistance (200 °C), and good heat transfer performance. In this embodiment, the first adaptive layer 110a and the second adaptive layer 110b can respectively adopt thermal conductive silica gel. In other implementation manners, they can be replaced with thermal conductive silica gel of other specifications with a high elastic modulus, or a combination of no less than two springs with a high elastic coefficient and a flexible steel plate.

[0103] The second adaptive layer 110b can be replaced with thermal conductive silica gel with a high elastic modulus, or a combination of no less than two springs with a high elastic coefficient and a flexible steel plate. The first lubricating layer 150a and the second lubricating layer 150b can use PTFE polytetrafluoroethylene, aramid insulating paper, or PET polyester film.

[0104] Compared with the current hot pressing process, the first lubricating layer 150a and the second lubricating layer 150b in this embodiment can protect the surface diaphragm bonding layer of the main body 210 of the stacked battery cell 200, so that it does not displace or deform during the extension and contraction of the elastic deformation of the first adaptive layer 110a and the second adaptive layer 110b, and keep the surface of the main body 210 of the battery cell 200 flat and intact. The first adaptive layer 110a and the second adaptive layer 110b have a complete and effective hot pressing effect on the thinned area of the stacked battery cell, so that the electrodes and the diaphragm in the thinned area are subjected to a comprehensive hot pressing force, realizing the complete pressing of the hot pressing interface between the stacked battery cell body and the electrodes and the diaphragm in the thinned area, and overcoming the lithium plating problem caused by the insufficient adhesion between the electrodes and the diaphragm in the thinned area of the stacked battery cell under the condition of ultra-fast charging. Designing the first lubricating layer 150a and the second lubricating layer 150b to protect the surface diaphragm and electrodes of the battery cell improves the consistency of the hot pressing effect between the thinned area and the body area of the stacked battery cell, solves the problems of cyclic lithium plating and dark spots caused by poor consistency of the hot pressing effect of the stacked battery cell under the condition of ultra-fast charging, and improves the fast charging safety of the battery.

[0105] The above has introduced in detail a battery cell hot pressing jig provided by an embodiment of the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A core hot pressing fixture for being assembled on a hot press, the hot press comprising a first pressing plate and a second pressing plate which are oppositely arranged, characterized in that, The cell hot pressing fixture includes: A first adaptive layer disposed on the first pressing plate. The first adaptive layer is configured to be elastically deformed under an external force. The first adaptive layer is used to press against one surface of the cell to be hot pressed under the action of the first pressing plate. The first adaptive layer is elastically deformed and closely adheres to the cell to be hot pressed; and A second adaptive layer disposed on the second pressing plate. The second adaptive layer is configured to be elastically deformed under an external force. The second adaptive layer is used to press against the other surface of the cell to be hot pressed under the action of the second pressing plate. The second adaptive layer is elastically deformed and closely adheres to the cell to be hot pressed; It further includes a first transfer layer and a second transfer layer disposed opposite to each other; The first transfer layer is stacked on the side of the first adaptive layer facing the second adaptive layer. The first transfer layer is configured to be bent under the action of the elastic deformation of the first adaptive layer. The first transfer layer is used to press against one surface of the cell to be hot pressed under the action of the first pressing plate and the first adaptive layer. The first transfer layer is bent and closely adheres to the cell to be hot pressed; The first transfer layer is arranged to extend beyond the boundary of the main body on one side of the thinned area of the main body of the cell. The first transfer layer can be elastically deformed and bent on one side of the thinned area; The second transfer layer is stacked on the side of the second adaptive layer facing the first adaptive layer. The second transfer layer is configured to be bent under the action of the elastic deformation of the second adaptive layer. The second transfer layer is used to press against the other surface of the cell to be hot pressed under the action of the second pressing plate and the second adaptive layer. The second transfer layer is bent and closely adheres to the cell to be hot pressed; The second transfer layer is arranged to extend beyond the boundary of the main body on one side of the thinned area of the main body of the cell. The second transfer layer can be elastically deformed and bent on one side of the thinned area.

2. The cell hot pressing fixture according to claim 1, characterized in that, The materials of the first adaptive layer and the second adaptive layer are respectively heat-conducting silica gel; The first transfer layer and the second transfer layer are respectively spring steel sheets.

3. The cell hot pressing fixture according to claim 1, wherein, It further includes a first limiting member. The first limiting member includes a first body, a first protruding portion and a first bending portion; The first body is disposed on the first pressing plate. The first body has a first accommodating cavity for accommodating the first adaptive layer and the first transfer layer. A first opening communicating with the first accommodating cavity is formed on one side of the first body. The first protruding portion protrudes from the side of the first body facing the second transfer layer. The first protruding portion surrounds the first accommodating cavity. One end of the first protruding portion away from the first body is bent inward to form the first bending portion.

4. The cell hot pressing fixture according to claim 3, wherein The first body is U-shaped. A plurality of first mounting holes are spaced apart on the first body. The plurality of first mounting holes are arranged at intervals along the circumference of the first body. Among them, one of the first mounting holes is arranged at each corner of the first body.

5. The cell hot pressing fixture according to claim 3, characterized in that, It further includes a second limiting member. The second limiting member includes a second body, a second protruding portion and a second bending portion; The second body is disposed on the second pressing plate. The second body has a second accommodation cavity for accommodating the second adaptive layer and the second transfer layer. A second opening communicating with the second accommodation cavity is formed on one side of the second body. The second protruding portion protrudes from a surface of the second body facing the first transfer layer, and the second protruding portion surrounds the second accommodation cavity. Wherein, the second protruding portion includes a plurality of protruding units connected in sequence, and at least two adjacent protruding units are bent inward at an end away from the second body to form the second bending portion.

6. The cell hot pressing fixture according to claim 5, wherein, The second limiting member further includes a covering portion perpendicular to the plane where the second body is located. One end in the width direction of the covering portion is connected to the second bending portion, and the other end in the width direction of the covering portion faces the first limiting member.

7. The cell hot pressing jig according to claim 6, characterized in that, The covering portion is arranged along the circumferential direction of the second body to form an L-shaped cross section, and the covering portion surrounds a part of the second accommodation cavity.

8. The cell hot pressing fixture according to claim 7, characterized in that, The second protruding portion includes three protruding units connected in sequence, and the three protruding units are connected in sequence. Two adjacent protruding units among the three protruding units are bent inward at an end away from the second body to form the second bending portion, and the other protruding unit is not bent. The covering portion is disposed on the second bending portion.

9. The cell hot pressing fixture according to claim 1, characterized in that The deformation amount of the elastic deformation of the first adaptive layer in contact with the body region of the main body of the piezoelectric element to be heated is greater than the thickness difference between the body region and the thinned region of the main body of the piezoelectric element to be heated. The deformation amount of the elastic deformation of the second adaptive layer in contact with the body region of the main body of the piezoelectric element to be heated is greater than the thickness difference between the body region and the thinned region of the main body of the piezoelectric element to be heated.

10. A method for hot pressing an electric core of a hot pressing fixture for an electric core according to any one of claims 1 to 9, characterized in that, Comprising the following steps: Stack the first adaptive layer and the first transfer layer on the first pressing plate of the hot press, and stack the second adaptive layer and the second transfer layer on the second pressing plate of the hot press. Place the piezoelectric element to be heated on the second transfer layer. The first adaptive layer and the first transfer layer move towards the piezoelectric element to be heated under the drive of the first pressing plate. The first adaptive layer undergoes elastic deformation under the action of the first pressing plate and the piezoelectric element to be heated. The first transfer layer undergoes bending deformation under the action of the elastic deformation of the first adaptive layer and is closely attached to a surface of the piezoelectric element to be heated. The second adaptive layer undergoes elastic deformation under the action of the second pressing plate and the piezoelectric element to be heated. The second transfer layer undergoes bending deformation under the action of the elastic deformation of the second adaptive layer and is closely attached to the other surface of the piezoelectric element to be heated.

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