End socket assembly, soft package battery cell side edge packaging technology and soft package battery cell

Abstract

The invention provides an end socket assembly, a soft package battery cell side edge packaging process and a soft package battery cell. The sealing head assembly comprises a barrier plate and two sealing heads; the two sealing heads are oppositely arranged and form a pressing gap capable of accommodating two layers of aluminum plastic films; the press-fit gap comprises a high-temperature press-fit area and a low-temperature press-fit area, in the stacking direction of the two layers of aluminum plastic films, the height size of the high-temperature press-fit area is smaller than that of the low-temperature press-fit area, and the temperature of the high-temperature press-fit area is larger than the melting point of the inner side heat sealing layer in the aluminum plastic film and the temperature of the low-temperature press-fit area; the barrier plate is located on one side of the high-temperature pressing area, and a set distance exists between the barrier plate and the edge of the high-temperature pressing area; and the barrier plate completely covers the cut surfaces of the two layers of aluminum plastic films along the stacking direction. Under the action of the sealing head assembly, the heat sealing layers on the inner sides of the two layers of aluminum plastic films are fused and combined together and partially overflow to the gap between the barrier plate and the sealing head to form an excessive glue protection layer on the cut surface, and the side edge of the soft package battery cell is safe and reliable in quality due to the insulation protection effect of the excessive glue protection layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery cell packaging, and more particularly to a head assembly, a soft package battery cell side edge packaging process and a soft package battery cell. BACKGROUND

[0002] The soft package battery cell includes an aluminum plastic film and a core body packaged in the aluminum plastic film. The aluminum plastic film is generally composed of an outer protective layer (such as a nylon layer), a middle barrier layer (such as an aluminum foil layer), and an inner heat sealing layer (such as a polypropylene-PP layer). In the related art, the side edge of the soft package battery cell is prone to have a leakage voltage due to damage to the inner heat sealing layer of the aluminum plastic film during the packaging manufacturing process. The conventional method is to paste adhesive paper for insulation at the side edge, which increases the use of adhesive paper and the adhesive process at the side edge, thereby increasing the manufacturing cost. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide a head assembly, a soft package battery cell side edge packaging process and a soft package battery cell to solve the technical problem of increased manufacturing cost in the related art.

[0004] In a first aspect, the embodiments of the present application provide a head assembly for packaging of two layers of aluminum plastic films arranged in a stack in a soft package battery cell, comprising: two heads, the two heads being oppositely arranged and forming a pressing gap capable of accommodating the two layers of aluminum plastic films; the pressing gap includes a high-temperature pressing area and a low-temperature pressing area adjacent to the high-temperature pressing area, in the stacking direction of the two layers of aluminum plastic films, the height dimension of the high-temperature pressing area is less than the height dimension of the low-temperature pressing area, the temperature of the high-temperature pressing area is greater than the melting point of the inner heat sealing layer in the aluminum plastic film and the temperature of the low-temperature pressing area; and a blocking plate located on the side of the high-temperature pressing area away from the low-temperature pressing area and having a certain distance from the edge of the high-temperature pressing area; the blocking plate can completely cover the cut surface of the two layers of aluminum plastic films in the stacking direction.

[0005] In one of the embodiments, the high-temperature pressing area includes a high-temperature transition area and a high-temperature overflow area, the high-temperature transition area is connected between the high-temperature overflow area and the low-temperature pressing area; in the stacking direction of the two layers of aluminum plastic films, the height dimension of the high-temperature transition area is greater than the height dimension of the high-temperature overflow area.

[0006] In one of the embodiments, the head includes a first pressing surface, a second pressing surface and a transition pressing surface, between which two first pressing surfaces, the low-temperature pressing area is formed, between which two second pressing surfaces, the high-temperature overflow area is formed, and between which two transition pressing surfaces, the high-temperature transition area is formed; the first pressing surface is a plane, and / or the second pressing surface is a plane, and / or the transition pressing surface is a plane extending obliquely from the first pressing surface to the second pressing surface.

[0007] In one of the embodiments, the direction from the low-temperature pressing area to the high-temperature pressing area is defined as the first direction, and in the first direction, the width dimension of the low-temperature pressing area is 1mm-3mm, the width dimension of the high-temperature transition area is 0.5mm-1.5mm, and the width dimension of the high-temperature overflow area is 0.5mm-2mm.

[0008] In one of the embodiments, the inner heat sealing layer is a PP layer, and the temperature of the high-temperature pressing area is 200℃-220℃; and / or the temperature of the low-temperature pressing area is less than or equal to the melting point of the inner heat sealing layer in the aluminum-plastic film; and / or the head is provided with a chamfer on the side of the low-temperature pressing area away from the high-temperature pressing area, and the chamfer is inclined to the side away from the aluminum-plastic film.

[0009] In one of the embodiments, the predetermined distance is 0.3mm-0.8mm.

[0010] In one of the embodiments, the blocking plate includes a plate body and an anti-sticking layer arranged in a stack with the plate body, and the anti-sticking layer is located on the side of the plate body facing the head.

[0011] In one of the embodiments, the anti-sticking layer is a Teflon coating.

[0012] In the above head assembly, since the temperature of the high-temperature pressing area between the two heads is higher than the melting point of the inner heat sealing layer in the aluminum-plastic film, the inner heat sealing layer will be melted and stably combined together during the pressing and packaging process. At the same time, since the height dimension of the high-temperature pressing area is smaller than the height dimension of the low-temperature pressing area, the two layers of aluminum-plastic film will be subjected to greater extrusion force at the high-temperature pressing area than at the low-temperature pressing area, and thus the melted material of the inner heat sealing layer will be extruded to the side of the high-temperature pressing area away from the low-temperature pressing area and overflow into the gap between the blocking plate and the head, thereby forming a glue overflow protection layer on the cut surface of the aluminum-plastic film, and further ensuring the quality and safety of the soft-pack battery cell due to the insulation protection of the glue overflow protection layer.

[0013] In a second aspect, the embodiments of the present application provide a soft-pack battery cell side edge packaging process, which is performed by using the above head assembly and includes the following steps: Pre-sealing operation: The two sealing heads press and seal the two layers of aluminum-plastic film at the positions corresponding to the sides of the soft-pack battery cell; Cutting operation: Cut the two layers of aluminum-plastic film along the reference edge line corresponding to the side of the soft-pack battery cell to obtain the cut surface; Resealing operation: Align the edge of the high-temperature pressing area between the two sealing heads with the cut surface, and set the baffle plate at a predetermined interval corresponding to the cut surface, so that the two sealing heads press and seal the two layers of aluminum-plastic film until the inner heat-sealing layers of the two aluminum-plastic films are fused together and overflow to the cut surface, covering at least the middle barrier layer of the two aluminum-plastic films.

[0014] In one embodiment, the pressure seal obtained by the pre-sealing operation coincides with the pressure seal obtained by the re-sealing operation. In the pre-sealing operation, the two layers of aluminum-plastic film are pressed and sealed to a first compression ratio of 32% ± 5%. In the re-sealing operation, the two layers of aluminum-plastic film are pressed and sealed to a second compression ratio of 50% ± 7%.

[0015] In one embodiment, when the two sealing heads press and seal the two layers of aluminum-plastic film, the pressing and sealing time is 2s to 8s, and the pressing and sealing pressure is 0.1Mpa to 0.5Mpa.

[0016] In one embodiment, the following steps are included after the resealing operation: Bending operation: Bending the two layers of aluminum-plastic film that are pressed together.

[0017] In the aforementioned side-packing process for pouch cells, during the lamination and encapsulation of the two aluminum-plastic films, the inner heat-sealing layers fuse together and overflow to the cut surface, forming an intermediate barrier layer—an overflow protective layer—covering the two aluminum-plastic films. Therefore, the pouch cells produced by this encapsulation process have reliable quality and safety at the sides due to the insulating protection provided by the overflow protective layer. Furthermore, since the overflow protective layer is formed directly during the lamination and encapsulation process of the two aluminum-plastic films, no additional steps or additional insulating tape are required after the lamination and encapsulation operation to address the side leakage voltage issue, thus reducing manufacturing costs.

[0018] Thirdly, this application provides a soft-pack battery cell manufactured by the above-described packaging process. The soft-pack battery cell is cubic in shape and has a top edge, a bottom edge, and two side edges. The top edge and the bottom edge are arranged opposite to each other, and the two side edges are arranged opposite to each other and connected between the top edge and the bottom edge. The soft-pack battery cell includes a core body and an aluminum-plastic film wrapped around the core body. The tabs of the core body extend beyond the aluminum-plastic film at the top edge. The aluminum-plastic film includes an outer protective layer, an inner heat-sealing layer, and an intermediate barrier layer. The intermediate barrier layer is connected between the outer protective layer and the inner heat-sealing layer. At the side edge, the two layers of aluminum-plastic film are stacked, and their inner heat-sealing layers are pressed together and fused together, overflowing to the cut surface to form an overflow protective layer that at least covers the intermediate barrier layer.

[0019] The beneficial effects of the soft-pack battery cell provided in this application embodiment are as follows: the inner heat-sealing layers of the two aluminum-plastic films are pressed together to form a first level of protection around the core, while the overflow protective layer can completely cover the intermediate barrier layer, thus forming a second level of protection together with the outer protective layer around the intermediate barrier layer. This prevents leakage due to exposure of the intermediate barrier layer. Therefore, even if the inner heat-sealing layer is damaged, causing the first level of protection to fail, the second level of protection can still prevent leakage voltage, making the side quality of the finished soft-pack battery cell reliable. In addition, since the inner heat-sealing layers of the two aluminum-plastic films are pressed together and overflow to form an overflow protective layer, the overflow protective layer and the inner heat-sealing layer are an integral structure. Therefore, it can be stably and reliably bonded to the cut surface with better sealing performance. Compared with the method of applying insulating tape to the side, it can achieve better protection effect, thereby making the side quality of the soft-pack battery cell more reliable. Furthermore, since the adhesive overflow protective layer is formed directly during the pressing and sealing process of the two aluminum-plastic films, no other processes are required after the pressing and sealing operation is completed, and no additional insulating tape is needed to solve the problem of side leakage voltage, thus reducing manufacturing costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a three-dimensional structural diagram of the end cap assembly provided in the embodiments of this application; Figure 2 for Figure 1 The main view of the end cap component shown; Figure 3A schematic diagram of the structure of the soft-pack battery cell provided in the embodiment of this application in the state where the sides are not folded; Figure 4 for Figure 3 The diagram shows a cross-sectional view of the two layers of aluminum-plastic film on the side of the soft-pack battery cell before it is pressed and sealed. Figure 5 for Figure 4 The diagram shows a structure in which an adhesive overflow protective layer is formed on the cut surface after the two layers of aluminum-plastic film are pressed and sealed together. Figure 6 A flowchart illustrating the side-packing process of the pouch cell provided in this application embodiment; The following are the labeling elements in the figure: 10. End cap assembly; 11. Baffle plate; 111. Plate body; 112. Anti-stick layer; 12. End cap; 121. First pressing surface; 122. Second pressing surface; 123. Transition pressing surface; 124. Chamfer; 13. Pressing gap; 131. High temperature pressing zone; 131a. High temperature transition zone; 131b. High temperature overflow zone; 132. Low temperature pressing zone; 80. Soft-pack battery cell; 81. Top edge; 82. Bottom edge; 83. Side edge; 84. Core body; 841. Tab; 85. Aluminum-plastic film; 851. Outer protective layer; 852. Inner heat-sealing layer; 853. Intermediate barrier layer; 854. Cut surface; 86. Excess adhesive protective layer; 87. Accommodation space. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] Combination Figures 1 to 6 As shown, this application protects a head assembly 10, a side packaging process for a soft-pack battery cell, and a soft-pack battery cell 80. The side packaging process for the soft-pack battery cell uses the head assembly 10 to achieve packaging at the side 83 of the soft-pack battery cell 80, thereby ensuring the quality of the side 83 of the finished soft-pack battery cell 80 and reducing manufacturing costs.

[0027] like Figure 3 As shown, the pouch cell 80 is cubic in shape and has a top edge 81, a bottom edge 82, and two side edges 83. The top edge 81 and the bottom edge 82 are arranged opposite each other, and the two side edges 83 are arranged opposite each other and connected between the top edge 81 and the bottom edge 82. Further, the pouch cell 80 includes a core body 84 and an aluminum-plastic film 85 wrapped around the core body 84. The tabs 841 of the core body 84 extend beyond the aluminum-plastic film 85 at the top edge 81.

[0028] It is understandable that after the aluminum-plastic film 85 is encapsulated, it can form a receiving space 87. The structures located within the receiving space 87 are all part of the core 84. The tab 841, as part of the core 84, is not wrapped by the aluminum-plastic film 85 but is exposed outside the aluminum-plastic film 85. For the soft-pack battery cell 80, the top edge 81, bottom edge 82, and side edge 83 are defined with the tab 841 as a reference. The side where the tab 841 is located is the top edge 81, and the side opposite to the top edge 81 is the bottom edge 82. The two side edges 83 are located on both sides of the core 84, and the two side edges 83, together with the top edge 81 and the bottom edge 82, form a rectangular arrangement.

[0029] Combination Figures 3 to 5 As shown, in this application, the aluminum-plastic film 85 includes an outer protective layer 851, an inner heat-sealing layer 852, and an intermediate barrier layer 853, with the intermediate barrier layer 853 connecting the outer protective layer 851 and the inner heat-sealing layer 852. At the side 83 of the soft-pack battery cell 80, the two aluminum-plastic films 85 are stacked, and their inner heat-sealing layers 852 are pressed together and fused together, overflowing to the cut surface 854 to form an overflow protective layer 86 that at least covers the intermediate barrier layer 853. In this application, the outer protective layer 851 is made of nylon, the intermediate barrier layer 853 is made of aluminum foil, and the inner heat-sealing layer 852 is made of polypropylene (PP).

[0030] It is understandable that, for the side 83 of the pouch cell 80, before the encapsulation process, such as... Figure 4 As shown, the two aluminum-plastic films 85 are stacked, with the inner heat-sealing layers 852 close to each other and the two outer protective layers 851 far apart. After the encapsulation operation, as shown... Figure 5 As shown, the inner heat-sealing layers 852 of the two aluminum-plastic films 85 are pressed together and fused into one. During the pressing process, the inner heat-sealing layers 852 are subjected to compression, and some material overflows to the cut surface 854 (the cross-section formed by cutting the two aluminum-plastic films 85) and solidifies on the cut surface 854 to form an overflow protective layer 86. Thus, the overflow protective layer 86 and the two fused inner heat-sealing layers 852 become an integral structure. On the cut surface 854, the entire cut surface 854 can be completely covered by the overflow protective layer 86, or a part of the cut surface 854 can be left uncovered. As long as the intermediate barrier layer 853 of the two aluminum-plastic films 85 is completely covered by the overflow protective layer 86, the problem of leakage voltage due to exposure of the intermediate barrier layer 853 can be avoided.

[0031] Therefore, the inner heat-sealing layers 852 of the two aluminum-plastic films 85 are connected together to form a first level of protection around the core 84. The adhesive overflow protection layer 86 and the outer protection layer 851 together form a second level of protection around the intermediate barrier layer 853. Even if the inner heat-sealing layer 852 is damaged, causing the first level of protection to fail, the second level of protection can still prevent leakage voltage, making the side 83 of the finished soft-pack battery cell 80 reliable. In addition, since the inner heat-sealing layer 852 and the adhesive overflow protection layer 86 of the two aluminum-plastic films 85 are an integral structure, the adhesive overflow protection layer 86 can be stably and reliably bonded to the cut surface 854 with good sealing performance. Compared with the method of applying insulating tape to the cut surface 854, it can achieve better protection effect, thus making the side 83 of the soft-pack battery cell 80 more reliable. Furthermore, since the overflow protective layer 86 is formed directly during the pressing and encapsulation process of the two aluminum-plastic films 85, no other processes are required after the pressing and encapsulation operation is completed, and no additional insulating tape is needed to solve the leakage voltage problem on the side 83, thus reducing manufacturing costs.

[0032] The head assembly 10 of the present application embodiment will be described below.

[0033] Combination Figures 1 to 5As shown, the end cap assembly 10 includes a baffle plate 11 and two end caps 12. The two end caps 12 are arranged opposite each other and form a pressing gap 13 capable of accommodating two layers of aluminum-plastic film 85. The pressing gap 13 includes a high-temperature pressing zone 131 and a low-temperature pressing zone 132 adjacent to the high-temperature pressing zone 131. In the stacking direction of the two layers of aluminum-plastic film 85 (i.e., the direction shown by the Z-axis), the height dimension of the high-temperature pressing zone 131 is smaller than the height dimension of the low-temperature pressing zone 132, and the temperature of the high-temperature pressing zone 131 is greater than the melting point of the inner heat-sealing layer 852 in the aluminum-plastic film 85 and the temperature of the low-temperature pressing zone 132. The baffle plate 11 is located on the side of the high-temperature pressing zone 131 away from the low-temperature pressing zone 132 and has a predetermined distance D4 from the edge of the high-temperature pressing zone 131. The baffle plate 11 can completely cover the cut surface 854 of the two layers of aluminum-plastic film 85 along the stacking direction.

[0034] It is understood that when the end cap assembly 10 is used to press and encapsulate the side 83 of the soft-pack battery cell 80, the two end caps 12 are arranged opposite to each other on both sides of the two aluminum-plastic films 85 in the stacking direction of the two layers of aluminum-plastic films 85. The low-temperature pressing area 132 formed between the two end caps 12 is close to the core 84, while the high-temperature pressing area 131 is far away from the core 84 and closer to the cut surface 854 at the edge of the two layers of aluminum-plastic films 85.

[0035] Furthermore, since the temperature of the high-temperature pressing zone 131 is higher than the melting point of the inner heat-sealing layer 852, during the pressing and sealing process, the inner heat-sealing layer 852 on the two aluminum-plastic films 85 located in the high-temperature pressing zone 131 will melt and bond together. Simultaneously, since the height of the high-temperature pressing zone 131 is smaller than that of the low-temperature pressing zone 132, the two aluminum-plastic films 85 will experience a greater compressive force at the high-temperature pressing zone 131 than at the low-temperature pressing zone 132, resulting in a greater thickness change. Thus, the low-temperature pressing zone 132 can achieve a transition of pressing action in the first direction (from the low-temperature pressing zone 132 to the high-temperature pressing zone 131, i.e., the direction shown by the X-axis). This is more conducive to squeezing the material of the inner heat-sealing layer 852 towards the side of the high-temperature pressing zone 131 away from the low-temperature pressing zone 132 and overflowing it to the cutting surface 854. It also helps maintain a relatively large thickness of the inner heat-sealing layer 852 at the low-temperature pressing zone 132, reducing the possibility of damage and breakage. Meanwhile, since the temperature at the low-temperature pressing zone 132 is lower than that at the high-temperature pressing zone 131, the low-temperature pressing zone 132 can separate the core 84 from the high-temperature pressing zone 131 to avoid the high temperature of the high-temperature pressing zone 131 from having an adverse effect on the core 84.

[0036] Combination Figures 1 to 5As shown, further, the baffle plate 11 is disposed on one side of the two end caps 12 and close to the high-temperature pressing area 131, and has a predetermined distance D4 between it and the edge of the high-temperature pressing area 131. This predetermined distance is also the thickness of the overflow protective layer 86 formed on the cutting surface 854. It should be noted that during the pressing operation, the edge of the high-temperature pressing area 131 needs to be aligned with the cutting surface 854, so the distance between the cutting surface 854 and the baffle plate 11 is also a predetermined distance. The baffle plate 11 needs to be disposed corresponding to the cutting surface 854 of the two layers of aluminum-plastic film 85, and the baffle plate 11 can also completely cover the cutting surface 854.

[0037] Thus, during the process of pressing and sealing the two aluminum-plastic films 85 together by the two end caps 12, the material overflowing from the inner heat-sealing layer 852 can flow into the gap between the baffle plate 11 and the cut surface 854. The baffle plate 11 guides the flow of the overflowing material, thereby obtaining an overflow protective layer 86 on the cut surface 854 with the required thickness that can completely cover the intermediate barrier layer 853. This makes the side 83 of the soft-pack battery cell 80 reliable in quality and reduces manufacturing costs.

[0038] In the embodiments of this application, the high-temperature pressing zone 131 includes a high-temperature transition zone 131a and a high-temperature overflow zone 131b, with the high-temperature transition zone 131a connecting the high-temperature overflow zone 131b and the low-temperature pressing zone 132. In the lamination direction of the two aluminum-plastic films 85, the height of the high-temperature transition zone 131a is greater than the height of the high-temperature overflow zone 131b. It can be understood that the high-temperature transition zone 131a can serve as an intermediate transition between the low-temperature pressing zone 132 and the high-temperature overflow zone 131b under conditions of higher temperature.

[0039] The end cap 12 includes a first pressing surface 121, a second pressing surface 122, and a transition pressing surface 123. For two end caps 12, a low-temperature pressing zone 132 is formed between the two first pressing surfaces 121, a high-temperature overflow zone 131b is formed between the two second pressing surfaces 122, and a high-temperature transition zone 131a is formed between the two transition pressing surfaces 123. The first pressing surface 121 is a plane, the second pressing surface 122 is a plane, and the transition pressing surface 123 is a plane that extends obliquely from the first pressing surface 121 to the second pressing surface 122.

[0040] It can be understood that the height dimension of the low-temperature pressing zone 132 between the two end caps 12 is also the distance H1 between the first pressing surfaces 121 on the two end caps 12, and the height dimension of the high-temperature overflow zone 131b between the two end caps 12 is also the distance H2 between the second pressing surfaces 122 on the two end caps 12, and H2 is less than H1. The height dimension of the high-temperature transition zone 131a between the two end caps 12 is also the distance between the transition pressing surfaces 123 on the two end caps 12, which is between H1 and H2. Therefore, the average height dimension of the high-temperature pressing zone 131 is less than the height dimension of the low-temperature pressing zone 132.

[0041] Therefore, the two first pressing surfaces 121 are relatively far apart, resulting in a relatively small extrusion effect on the two layers of aluminum-plastic film 85, while the two second pressing surfaces 122 are relatively close together, resulting in a relatively large extrusion effect on the two layers of aluminum-plastic film 85. The two transition pressing surfaces 123 are sloped and connected between the first pressing surfaces 121 and the second pressing surfaces 122. Thus, the extrusion effect on the two layers of aluminum-plastic film 85 is between that of the two first pressing surfaces 121 and the two second pressing surfaces 122. In this way, the two layers of aluminum-plastic film 85 after pressing and sealing exhibit a gradually decreasing thickness in the first direction, resulting in superior structural strength. Furthermore, the sloped arrangement of the two transition pressing surfaces 123 between the first pressing surfaces 121 and the second pressing surfaces 122 also helps to promote the flow of the molten material of the inner heat-sealing layer 852 along the first direction towards the high-temperature overflow zone 131b and the cut surface 854.

[0042] It should be noted that, in other embodiments, one or more of the first pressing surface 121, the second pressing surface 122, and the transition pressing surface 123 can be configured as curved surfaces as needed. Furthermore, during the process of pressing and encapsulating the two layers of aluminum-plastic film 85 with the two end caps 12, the two end caps 12 gradually approach each other, and the height dimensions of the low-temperature pressing area 132 and the high-temperature overflow area 131b are dynamically changing. Therefore, the comparison of their sizes is based on the condition that the two end caps 12 are relatively stationary. Furthermore, during the process of pressing and sealing the two aluminum-plastic films 85 with the two end caps 12, the two end caps 12 gradually approach each other. The height dimension of the low-temperature pressing zone 132 will gradually decrease to a minimum value, and the height dimension of the high-temperature overflow zone 131b will also gradually decrease to a minimum value. The minimum values ​​of the two also determine the thickness of the two aluminum-plastic films 85 at the low-temperature pressing zone 132 and the high-temperature overflow zone 131b after pressing and sealing. This is related to the initial total thickness of the two aluminum-plastic films 85 and the final compression ratio to be achieved, and therefore is not limited here.

[0043] Specifically, in this application, in the first direction, the width of the low-temperature pressing zone 132 is 1mm to 3mm, the width of the high-temperature transition zone 131a is 0.5mm to 1.5mm, and the width of the high-temperature overflow zone 131b is 0.5mm to 2mm. For example...Figure 2 As shown, the width dimension of the low temperature pressing zone 132 is D1, the width dimension of the high temperature transition zone 131a is D2, and the width dimension of the high temperature overflow zone 131b is D3.

[0044] The transition pressing surface 123 is set at an angle θ = 45° between the first pressing surface 121 and the second pressing surface 122, so the difference between H1 and H2 is equal to the width dimension D3 of the high-temperature transition zone 131a. In other embodiments, the angle θ of the transition pressing surface 123 can also be changed between 30° and 60°.

[0045] In this application, the end cap 12 has a chamfer 124 on the side of the low-temperature pressing zone 132 away from the high-temperature pressing zone 131, and the chamfer 124 is inclined towards the side away from the aluminum-plastic film 85. Specifically, the inclination angle of the chamfer 124 is 45° and the radius of curvature (R) is 0.3mm to 1.0mm. It can be understood that if the chamfer 124 is not provided, the sharp edge of the first pressing surface 121 will damage the aluminum-plastic film 85 when pressing it. This problem can be avoided by providing the chamfer 124.

[0046] In this application, the inner heat-sealing layer 852 is a PP layer. The temperature of the high-temperature pressing zone 131 is 200℃~220℃, and the temperature of the low-temperature pressing zone 132 is less than or equal to the melting point of the inner heat-sealing layer 852 in the aluminum-plastic film 85. Specifically, for the PP layer, its melting point is 170℃~185℃. By setting the temperature of the high-temperature pressing zone 131 to 200℃~220℃, the PP layer can be melted, and the PP layer material is squeezed outwards to the cut surface 854 as the two end caps 12 approach each other. For the low-temperature pressing zone 132, its designed temperature is 140℃~160℃, which is lower than the melting point of the PP layer. However, under the high-temperature heat conduction of the high-temperature pressing zone 131, the temperature of the low-temperature pressing zone 132 can reach 170℃~185℃, which is approximately close to or equal to the melting point of the PP layer, and thus can also play the role of melting the PP layer.

[0047] In this application, the predetermined spacing D4 is 0.3mm to 0.8mm. It can be understood that the spacing between the baffle plate 11 and the cut surface 854 is also a predetermined spacing, which is also the thickness of the adhesive overflow protective layer 86 formed on the cut surface 854. By setting the predetermined spacing to 0.3mm to 0.8mm, it is possible to avoid the gap between the baffle plate 11 and the cut surface 854 being too small, resulting in the adhesive overflow protective layer 86 being too thin to provide adequate insulation protection. It is also possible to avoid the gap between the baffle plate 11 and the cut surface 854 being too large, preventing the molten material of the inner heat-sealing layer 852 from filling the gap and thus ensuring the adhesive overflow protective layer 86 does not completely cover the intermediate barrier layer 853.

[0048] Specifically, in this application, the baffle plate 11 includes a plate body 111 and an anti-adhesive layer 112 stacked on top of the plate body 111. The anti-adhesive layer 112 is located on the side of the plate body 111 facing the end cap 12. Specifically, the anti-adhesive layer 112 is a Teflon coating. It can be understood that the side of the plate body 111 facing the end cap 12 is also the side of the plate body 111 facing the cut surface 854. By providing the anti-adhesive layer 112 thereon, the anti-adhesive layer 112 can come into contact with the molten material overflowing from the inner heat-sealing layer 852 onto the cut surface 854 without sticking. This ensures that after the molten material solidifies on the cut surface 854 to form an overflow protective layer 86, when the baffle plate 11 is separated from the overflow protective layer 86, the baffle plate 11 will not pull the overflow protective layer 86, thus ensuring that the overflow protective layer 86 adheres well to the cut surface 854 and has a good insulating protection effect.

[0049] Combination Figures 1 to 6 As shown, this application also protects a side-packing process for a pouch cell, which includes the following steps: S410, Pre-sealing operation: The two caps 12 press and seal the two layers of aluminum-plastic film 85 at the positions corresponding to the side 83 of the soft-pack cell 80.

[0050] S420, Cutting operation: Cut the two layers of aluminum-plastic film 85 along the reference edge line corresponding to the side edge 83 of the soft-pack battery cell 80 to obtain the cut surface 854.

[0051] S430, Resealing operation: Align the edge of the high-temperature pressing area 131 between the two end caps 12 with the cut surface 854, and set the baffle plate 11 at a predetermined interval to correspond to the cut surface 854, so that the two end caps 12 press and seal the two layers of aluminum-plastic film 85 until the inner heat-sealing layer 852 of the two layers of aluminum-plastic film 85 fuses into one and overflows to the cut surface 854, covering at least the middle barrier layer 853 of the two layers of aluminum-plastic film 85.

[0052] It is understandable that before the cutting operation, the total width of the two layers of aluminum-plastic film 85 in the first direction will be greater than the actual target width. Therefore, the excess aluminum-plastic film 85 in the first direction can be removed by the cutting operation. For the soft-pack battery cell 80, a reference edge line will be designed on each of its two sides 83. The width of the aluminum-plastic film 85 between the two reference edge lines is the actual target width. The position of the two reference edge lines is the position where the aluminum-plastic film 85 is to be cut. After the two layers of aluminum-plastic film 85 are cut along the reference edge lines, the cross-section of the two layers of aluminum-plastic film 85 is the cutting surface 854.

[0053] It is understandable that, for the pre-sealing operation, the pressed imprint obtained after pressing and sealing the two layers of aluminum-plastic film 85 with two sealing heads 12 is the effective seal. The boundary of the effective seal away from the core 84 can coincide with the reference edge line in the cutting operation, or the effective seal can also be located on the side of the reference edge line closer to the core 84 with a certain distance between the boundary and the reference edge line. Furthermore, for the re-sealing operation, the pressing and sealing operation is mainly to achieve the melting and extrusion of the inner heat-sealing layer 852 and to make the overflowing material cover the cutting surface 854 to form an overflow protective layer 86. Therefore, the edge of the high-temperature pressing area 131 between the two sealing heads 12 away from the low-temperature pressing area 132 needs to be aligned with the cutting surface 854, and the baffle plate 11 needs to correspond to the cutting surface 854 and be set at a predetermined distance from it. Thus, the pressing seal in the re-sealing operation and the pressing seal in the pre-sealing operation can completely coincide, partially overlap, or have a gap.

[0054] In this application, in order to make full and effective use of the aluminum-plastic film 85 on the side 83 of the soft-pack battery cell 80, the pressing seal in the resealing operation is completely overlapped with the pressing seal in the presealing operation. In the presealing operation, the two layers of aluminum-plastic film 85 are pressed and sealed to a first compression ratio of 32% ± 5%. In the resealing operation, the two layers of aluminum-plastic film 85 are pressed and sealed to a second compression ratio of 50% ± 7%. Thus, under the two pressing operations, an overflow protective layer 86 with the required thickness and which can completely cover the intermediate barrier layer 853 can be formed on the cut surface 854.

[0055] In this application, when the two sealing heads 12 press and seal the two layers of aluminum-plastic film 85, the pressing and sealing time is 2s to 8s, and the pressing and sealing pressure is 0.1Mpa to 0.5Mpa. It can be understood that the pressing and sealing time of the two layers of aluminum-plastic film 85 in the resealing operation is longer than that in the presealing operation, and the pressing and sealing pressure of the two layers of aluminum-plastic film 85 in the resealing operation is also greater than that in the presealing operation, so that the two layers of aluminum-plastic film 85 can reach the second compression ratio after the resealing operation, and it is also beneficial to the formation of the overflow adhesive protective layer 86 on the cut surface 854.

[0056] In this application, after the resealing operation, the process further includes: S440, bending operation: bending the pressed seal of the two layers of aluminum-plastic film 85. It can be understood that if the pressed seal in the resealing operation completely overlaps with the pressed seal in the pre-sealing operation, the pressed seal needs to be bent after the resealing operation; that is, the side 83 of the soft-pack battery cell 80 is bent along the edge of the pressed seal near the core 84. However, if the pressed seal in the resealing operation does not completely overlap with the pressed seal in the pre-sealing operation, the side 83 of the soft-pack battery cell 80 needs to be bent along the edge of the pressed seal in the pre-sealing operation near the core 84 after the resealing operation.

[0057] It should be noted that the aluminum-plastic film 85 supplied can be obtained by folding to form the two layers of aluminum-plastic film 85 as required above, and the fold seam will correspond to the bottom edge 82 of the soft-pack battery cell 80 without the need for pressing and encapsulation. The side encapsulation process of the soft-pack battery cell in this embodiment only involves the encapsulation of the two layers of aluminum-plastic film 85 at the side edge 83 of the soft-pack battery cell 80, and does not involve the encapsulation of the top edge 81 of the soft-pack battery cell 80. The encapsulation of the top edge 81 of the soft-pack battery cell 80 can be completed using existing encapsulation operations, which will not be described in detail here.

[0058] Furthermore, the soft-pack battery cell 80 obtained based on the side-packing process of this application, after being immersed in salt water for sealing tests with a conventional soft-pack battery cell 80, exhibits the following comparison:

[0059] It can be seen that the initial voltage difference of the soft-pack battery cell 80 in this application is basically the same as that of the conventional soft-pack battery cell 80, both being in a normal state. However, when immersed in salt water for sealing test, the voltage difference of the soft-pack battery cell 80 in this application is only 30mV after the test, with little change in voltage difference, indicating that its sealing performance is good, it has not been corroded by salt water, and its structure is safe and reliable. In contrast, the voltage difference of the conventional soft-pack battery cell 80 is 4300mV after the test, with a large change in voltage difference and bulging phenomenon, indicating that salt water seepage occurred during the test, causing internal short circuit or electrochemical reaction, resulting in voltage imbalance and potential safety hazards in the structure.

[0060] In summary, the soft-pack battery cell 80 obtained based on the side packaging process of this application has its side 83 covered by an adhesive overflow protection layer 86, where the cut surfaces 854 of the two aluminum-plastic films 85 are covered. Thus, the adhesive overflow protection layer 86 can play a good insulating protection role at the side 83 of the soft-pack battery cell 80, making the side 83 of the soft-pack battery cell 80 safe and reliable.

[0061] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A head assembly for packaging of two layers of aluminum-plastic film in a soft-pack battery cell, characterized in that, The application relates to a sealing head for sealing two layers of aluminum-plastic film. The sealing head comprises two sealing heads which are oppositely arranged and form a pressing gap capable of accommodating the two layers of aluminum-plastic film; the pressing gap comprises a high-temperature pressing area and a low-temperature pressing area adjacent to the high-temperature pressing area; in the stacking direction of the two layers of aluminum-plastic film, the height dimension of the high-temperature pressing area is smaller than that of the low-temperature pressing area, and the temperature of the high-temperature pressing area is higher than the melting point of the inner heat-sealing layer in the aluminum-plastic film and the temperature of the low-temperature pressing area; and a blocking plate is arranged on the side of the high-temperature pressing area away from the low-temperature pressing area and has a certain interval with the edge of the high-temperature pressing area; the blocking plate can completely cover the cutting section of the two layers of aluminum-plastic film in the stacking direction. The high-temperature pressing area comprises a high-temperature transition area and a high-temperature overflow area, and the high-temperature transition area is connected between the high-temperature overflow area and the low-temperature pressing area; in the stacking direction of the two layers of aluminum-plastic film, the height dimension of the high-temperature transition area is larger than that of the high-temperature overflow area.

2. The head assembly of claim 1, wherein The sealing head comprises a first pressing surface, a second pressing surface and a transition pressing surface; for the two sealing heads, the low-temperature pressing area is formed between the two first pressing surfaces, the high-temperature overflow area is formed between the two second pressing surfaces, and the high-temperature transition area is formed between the two transition pressing surfaces; the first pressing surface is a plane, and / or the second pressing surface is a plane, and / or the transition pressing surface is a plane which extends from the first pressing surface to the second pressing surface.

3. The head assembly of claim 2, wherein, The direction from the low-temperature pressing area to the high-temperature pressing area is defined as the first direction; in the first direction, the width dimension of the low-temperature pressing area is 1mm-3mm, the width dimension of the high-temperature transition area is 0.5mm-1.5mm, and the width dimension of the high-temperature overflow area is 0.5mm-2mm.

4. The head assembly of claim 2, wherein The inner heat-sealing layer is a PP layer, the temperature of the high-temperature pressing area is 200 DEG C-220 DEG C, and / or the temperature of the low-temperature pressing area is less than or equal to the melting point of the inner heat-sealing layer in the aluminum-plastic film, and / or the sealing head is provided with a chamfer on the side of the low-temperature pressing area away from the high-temperature pressing area, and the chamfer is inclined to the side away from the aluminum-plastic film.

5. The head assembly of claim 1, wherein The certain interval is 0.3mm-0.8mm.

6. The head assembly of claim 1, wherein The blocking plate comprises a plate body and an anti-sticking layer which is arranged in the stacking direction of the plate body and is located on the side of the plate body facing the sealing head.

7. The head assembly of claim 1, wherein The anti-sticking layer is a Teflon coating.

8. The head assembly of claim 7, wherein, The application further relates to a sealing method for sealing two layers of aluminum-plastic film.

9. A process for side-sealing a pouch cell using the end assembly of any one of claims 1 to 8, wherein, The sealing method comprises the following steps: Pre-sealing operation: the two sealing heads press and seal the positions of the two layers of aluminum-plastic film corresponding to the side edges of the soft package battery cell; Cutting operation: the two layers of aluminum-plastic film are cut along the reference edge line corresponding to the side edges of the soft package battery cell to obtain a cutting section; Supplementary sealing operation: the edges of the high-temperature pressing area between the two sealing heads are arranged in alignment with the cutting section, the blocking plate is arranged in the certain interval corresponding to the cutting section, and the two sealing heads press and seal the two layers of aluminum-plastic film until the inner heat-sealing layers of the two layers of aluminum-plastic film are fused into one and overflow to the cutting section to cover at least the intermediate barrier layer of the two layers of aluminum-plastic film.

10. The soft-pack battery cell side edge encapsulation process of claim 9, wherein, The compression seal obtained by the pre-sealing operation coincides with the compression seal obtained by the post-sealing operation, in the pre-sealing operation, two layers of the aluminum plastic film are compression sealed to a first compression ratio, the first compression ratio is 32%±5%, in the post-sealing operation, two layers of the aluminum plastic film are compression sealed to a second compression ratio, the second compression ratio is 50%±7%.

11. The soft-pack battery cell side edge encapsulation process of claim 9, wherein, When the two sealing heads compression seal the two layers of the aluminum plastic film, the compression sealing time is 2s-8s, and the compression sealing pressure is 0.1Mpa-0.5Mpa.

12. The soft-pack battery cell side-seal process of claim 9, wherein, The post-sealing operation further comprises the following steps: The bending operation: bending the compression seal of the two layers of the aluminum plastic film.

13. A pouch cell made by the packaging process of any one of claims 9 to 12, characterized in that, The soft package battery cell is cuboid-shaped and has a top edge, a bottom edge and two side edges, the top edge and the bottom edge are oppositely arranged, and the two side edges are oppositely arranged and connected between the top edge and the bottom edge; the soft package battery cell comprises a core body and an aluminum plastic film wrapped around the periphery of the core body; the tab of the core body protrudes out of the aluminum plastic film at the top edge; the aluminum plastic film comprises an outer protective layer, an inner heat sealing layer and an intermediate barrier layer, the intermediate barrier layer is connected between the outer protective layer and the inner heat sealing layer; at the side edge, the two layers of the aluminum plastic film are stacked and the inner heat sealing layers thereof are compression sealed and fused into one and overflow to the cutting surface to form an overflow adhesive protective layer covering at least the intermediate barrier layer.

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