Tab connecting structure

Abstract

The utility model relates to the technical field of battery cell manufacturing, and particularly provides a tab connecting structure. The lithium ion battery comprises a plurality of tabs electrically connected with an electrode plate, each tab is fixedly connected with at least one composite structure, and the composite structures on every two adjacent tabs are at least partially fused to form a polymer; according to the multi-layer electrode plate disclosed by the utility model, at least part of the composite structure is fused to form the polymer, so that the thickness of the polymer is reduced, and meanwhile, the electrode plate is easier to bend (compared with a polymer formed by bonding an existing tab adhesive and a corresponding tab); the distance between the polymer formed by adopting the composite structure and one end part of the battery cell is smaller than the distance between the polymer formed by adopting the existing tab glue and one end part of the battery cell, so that the area occupied by the tab connecting structure on the head part of the battery cell is reduced, and the length of an electrode plate can be conveniently extended in the design process of the battery cell; and the mass energy density of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery core manufacturing, and more specifically to a pole ear connection structure. Background Art

[0002] In the process of soft pack battery, combined with Figure 1 Before packaging, the stacked bare cells 2' need to be pre-welded, cut and welded. When cutting the tabs 22', due to the limitation of the tab glue 21', transfer welding needs to be applied to the tabs 22' with multiple layers and the tabs 22' covered with the tab glue 21'. In addition, the tab 22' welding position 20' needs to be bent twice to Figure 1 The position shown in Figure 1 The first fold and the second fold of the battery cell are required before the tabs 22', tab glue 21' and aluminum-plastic film can be sealed during packaging (specifically top sealing). However, the aforementioned method will not only cause the tabs 22' to occupy a large space at the head of the battery cell, but also cause pitting. And when the length of the battery cell is determined after packaging, due to the aforementioned reasons, the pole piece cannot be extended during the battery cell design process, which also loses the energy density of the battery cell.

[0003] In order to solve the aforementioned technical problems, technicians in this field have proposed a solution to omit the welding process and reduce the number of times the pole tab is bent to reduce the head space of the battery cell occupied by the pole tab. However, this solution has a new problem, namely, how to make the pole tab easy to bend to reduce the head space of the battery cell occupied by the pole tab.

[0004] Based on this, it is urgent to invent a tab connection structure to solve the above-mentioned technical problems. Utility Model Content

[0005] The technical problem to be solved by the utility model is how to make the pole ear easy to bend so as to reduce the head space of the battery cell occupied by the pole ear. In view of the above problem, a pole ear connection structure is provided.

[0006] The utility model provides a technical solution to solve the above technical problems by providing a tab connection structure, the tab connection structure comprising:

[0007] A plurality of pole tabs electrically connected to the electrode sheet, each of the pole tabs being fixedly connected with at least one composite structure, and the composite structures on each two adjacent pole tabs being at least partially fused to form an aggregate.

[0008] Specifically, each of the composite structures includes at least one fusion layer, and the fusion layer is fixed to the lower surface of the pole ear stacked in the uppermost layer among the multiple pole ears; the fusion layer is fixed to the upper surface of the pole ear stacked in the lowermost layer among the multiple pole ears; the fusion layer is fixed to the upper surface and / or lower surface of each of the pole ears located in the middle.

[0009] More specifically, each of the composite structures further includes a support layer and a fusion layer.

[0010] More specifically, each of the composite structures further includes a support layer and at least two fusion layers.

[0011] Furthermore, the upper and lower surfaces of the support layer are respectively in contact with the tab and the fusion layer.

[0012] Furthermore, the upper and lower surfaces of the fusion layer are respectively in contact with the tab and the support layer.

[0013] Preferably, the number of the fusion layers is two, and the support layer is located between the two fusion layers.

[0014] More preferably, the melting point of the fusion layer is lower than the melting point of the support layer, and the ratio of the thickness of the support layer to the thickness of the fusion layer is 1:3.

[0015] Furthermore, the melting point of the fusion layer is between 100°C and 120°C.

[0016] Furthermore, the melting point of the support layer is between 100°C and 160°C.

[0017] The beneficial effect of the utility model is that the multilayer electrode sheet in the utility model is at least partially fused to form a polymer through the composite structure, so that the thickness of the polymer is reduced, and the electrode sheet is easier to bend (compared with the polymer and the corresponding tab formed by the existing tab glue bonding). In other words, the distance between the polymer formed by the aforementioned composite structure and one end of the battery cell is smaller than the distance between the polymer formed by the existing tab glue and one end of the battery cell, so as to reduce the area occupied by the tab connection structure at the head of the battery cell, thereby facilitating the extension of the length of the electrode sheet during the battery cell design process, thereby improving the mass energy density of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the existing tab welding process;

[0019] Reference numerals:

[0020] 2'-bare cell; 20'-welding position; 21'-ear glue; 22'-ear.

[0021] Figure 2 It is a structural schematic diagram of the cutting process of the tab in the battery cell of the utility model;

[0022] Figure 3 This utility model Figure 2 Schematic diagram of the structure of the middle electrode sheet, the tab and the composite structure;

[0023] Figure 4 This utility model Figure 3 A magnified image of the composite structure on the middle ear partially fused to form an aggregate;

[0024] Figure 5 It is a schematic structural diagram of the electrode sheet, the electrode tab and the composite structure in the first embodiment of the present invention;

[0025] Figure 6 It is a schematic structural diagram of the electrode sheet, the electrode tab and the composite structure in Embodiment 2 of the present utility model;

[0026] Figure 7 It is a schematic structural diagram of the electrode sheet, the electrode tab and the composite structure in the third embodiment of the present utility model;

[0027] Figure 8 It is a schematic structural diagram of the electrode sheet, the electrode tab and the composite structure in the fourth embodiment of the present utility model;

[0028] Fig. 9 This utility model Figure 8 Enlarged view of middle part B;

[0029] Fig.10 It is a schematic structural diagram of the electrode sheet, the electrode tab and the composite structure in Embodiment 5 of the present utility model;

[0030] Fig.11 This utility model Fig.10 Enlarged view of the middle C part;

[0031] Fig.12 It is a schematic structural diagram of the electrode sheet, the electrode tab and the composite structure in Embodiment 6 of the present utility model;

[0032] Fig.13 This utility model Fig.12 Enlarged view of part D in the middle.

[0033] Reference numerals:

[0034] 1-ear connection structure; 10-electrode sheet; 11-ear; 12-composite structure; 120-fusion layer; 1200-first fusion layer; 1201-second fusion layer; 121-support layer; 13-polymer; A-increased length of the electrode sheet. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and implementation methods. It should be understood that the specific implementation methods described here are only used to explain the utility model and are not used to limit the utility model.

[0036] The utility model provides a battery cell, which is used in equipment with weight requirements and compact space, such as drones, unmanned vehicles, intelligent robots and portable devices. It should be noted that the battery cell can be manufactured, used, sold and licensed separately.

[0037] refer to Figure 2 A battery cell includes a plurality of electrode sheets 10, which are stacked to form a battery cell. In connection with the technical problem solved by the utility model, how to make the tab 11 easy to bend, thereby shortening the distance between the polymer 13 and the end of the battery cell, and thus making the electrode sheet 10 longer in the battery cell design process (compared to the length of the electrode sheet 10 when the area occupied by the tab 11 of the existing battery cell head is large), please refer to Figure 2 At A in the middle. Obviously, the battery cell also includes a tab 11 attached to the edge of each layer of electrode sheet 10, and the tab 11 extends from the edge of the electrode sheet 10 to an end protruding from the battery cell, so that the electrode sheet 10 is connected to the external circuit of the battery. Obviously, the length direction of the electrode sheet 10 is parallel to the length direction of the tab 11, and the number of tabs 11 is adapted to the number of electrode sheets 10. For example, when the number of electrode sheets 10 is N (N is a positive integer, and N is not less than 2), the number of tabs 11 is (N-1).

[0038] In order to facilitate the bending of the pole tab 11, the battery cell further includes a composite structure 12, at least one composite structure 12 is fixed on each pole tab 11, and the composite structures 12 on each of the two adjacent pole tabs 11 are at least partially heated and fused to form a polymer 13 to reduce the thickness of the polymer 13. It can be understood that the technical solution of the utility model is to make the pole tab 11 easy to bend by reducing the thickness of the polymer 13. In addition, there is no need to implement a welding process in the aforementioned process, and the large pole tab 11 is also omitted.

[0039] Specifically, combined Figure 3 and Figure 4 Each composite structure 12 includes at least one fusion layer 120. Obviously, the fusion layer 120 is fixed to the lower surface of the uppermost tab 11 stacked among the multiple tabs 11, the fusion layer 120 is fixed to the upper surface of the uppermost tab 11 stacked among the multiple tabs 11, and the fusion layer 120 is fixed to the upper surface and / or lower surface of each tab 11 located in the middle.

[0040] In one embodiment, in order to prevent the polymer 13 from deforming and further reduce the thickness of the polymer 13 , each composite structure 12 further includes a support layer 121 and a single fusion layer 120 .

[0041] In one embodiment, in order to prevent the polymer 13 from deforming and ensure the firmness of the polymer 13 formed by hot melting, each composite structure 12 also includes a support layer 121 and at least two fusion layers 120. For the convenience of subsequent description and understanding, the two fusion layers 120 are named as the first fusion layer 1200 and the second fusion layer 1201 respectively. It can be understood that the material of the fusion layer 120 is a material suitable for the two fusion layers 120 to fuse with each other after heating; and / or, the material of the fusion layer 120 is a material suitable for the fusion layer 120 to fuse with other layers after heating. For example, the material of the fusion layer 120 can be PE material. The material of the support layer 121 can be PP material. In other specific embodiments, the material of the support layer 121 is not limited. Obviously, the number of composite structures 12 is compatible with the number of tabs 11, that is, at least one composite structure 12 can be attached to the upper surface or lower surface of the tab 11; or, at least two composite structures 12 can be attached to the upper and lower surfaces of the tab 11 respectively (see below for details).

[0042] In order to prevent the multiple composite structures 12 from deforming when they fuse together under heat (or the multiple composite structures 12 deforming under heat after forming the aggregate 13), the thickness of each composite structure 12 is between 2 μm and 10 μm. Of course, in other specific embodiments, the thickness of the composite structure 12 can also be other values.

[0043] In one specific embodiment, the length direction of the tab 11 is perpendicular to the length direction of the composite structure 12 .

[0044] In one specific embodiment, preferably, in order to ensure that the melting point of the material of the support layer 121 is higher than the melting point of the material of the fusion layer 120, the melting point of the material of the fusion layer 120 may be between 100° C. and 120° C., and the melting point of the material of the support layer 121 may be between 100° C. and 160° C. At the same time, it is also necessary to ensure that the thickness ratio of the support layer to the thickness of the fusion layer 120 is 1:3.

[0045] In one specific embodiment, in order to further reduce the area occupied by the cell head tab 11, the center line of the polymer 13 in the width direction coincides with the center line of the cell thickness direction. At this time, the area occupied by the tab 11 at the cell head is the minimum value that can be achieved.

[0046] Several implementations formed by combining different numbers of composite structures 12 on each tab 11 and different numbers of fusion layers 120 in each composite structure 12 are described in detail below:

[0047] Implementation Method 1

[0048] Combination Figure 5 A composite structure 12 is fixedly connected to each pole lug 11 in the pole lug connection structure 1, and each composite structure 12 includes a support layer 121 and a single fusion layer 120, and each support layer 121 is attached to the corresponding pole lug 11. The support layer 121 is located between the corresponding pole lug 11 and the fusion layer 120. After the pole lug connection structure 1 is heated to the melting point of the fusion layer 120 by hot melting, it is fused to the adjacent pole lug 11 through the fusion layer 120. After further heating to the melting point of the support layer 121, each pole lug 11 is fused to the adjacent pole lug 11 fused with the fusion layer 120 of the same composite structure 12 through the support layer 121 attached to each pole lug 11 to form an aggregate 13.

[0049] It should be noted that the fusion of each two adjacent tabs 11 is achieved by using a multi-layer composite structure 12 (different layers of the multi-layer composite structure 12 correspond to different melting points), so that the structure (here, the polymer 13 is not easy to deform) and chemical properties of the fused polymer 13 are more stable. By fixing a composite structure 12 on each tab 11 and including a fusion layer 120 on each tab 11, the thickness of the fused polymer is smaller (compared to fixing multiple composite structures 12 on each tab 11 and including multiple fusion layers 120 on each tab 11).

[0050] Implementation Method 2

[0051] Combination Figure 6 The difference between this embodiment and embodiment 1 is that the fusion layer 120 is located between the corresponding pole lug 11 and the support layer 121 in the same composite structure 12. After the pole lug connection structure 1 is heated to the melting point of the fusion layer 120 in a hot melt manner, the fusion layer 120 is fused to the corresponding pole lug 11. After further heating to the melting point of the support layer 121, each pole lug 11 fused with the fusion layer 120 in the same composite structure 12 is fused with the adjacent pole lug 11 through the support layer 121 to form an aggregate 13. Obviously, this combination makes the thickness of the fused aggregate 13 smaller (compared to the case where multiple composite structures 12 are fixed to each pole lug 11 and each pole lug 11 includes multiple fusion layers 120).

[0052] Implementation 3

[0053] Combination Figure 7, the difference between this embodiment and embodiment 1 is that each composite structure 12 includes a support layer 121 and two fusion layers 120. Among them, the support layer 121 is located between the two fusion layers 120 (refer to the above). After the pole ear connection structure 1 is heated to the melting point of the fusion layer in a hot melt manner, the first fusion layer 1200 and the second fusion layer 1201 are respectively fused to the corresponding pole ear 11 and the adjacent pole ear 11, and after continuing to heat to the melting point of the support layer 121, the corresponding pole ear 11 fused with the first fusion layer 1200 and the adjacent pole ear 11 fused with the second fusion layer 1201 are fused through the support layer 121 to form a polymer 13. Obviously. This combination method makes the structure of the fused polymer 13 more stable (compared with the polymer 13 formed by the scheme of embodiment 1). It should be noted that the positions of the first fusion layer 1200 and the second fusion layer 1201 are not limited.

[0054] Implementation 4

[0055] Combination Figure 8 and Fig. 9 , the difference between this embodiment and embodiment 1 is that among the multiple pole tabs 11 in the pole tab connection structure 1, a composite structure 12 is fixedly connected to the pole tab 11 stacked on the top layer, a composite structure 12 is fixedly connected to the pole tab 11 stacked on the bottom layer, and two composite structures 12 are fixedly connected to the pole tab 11 stacked between the top layer and the bottom layer. After the pole tab connection structure 1 is heated to the melting point of the fusion layer 120 in a hot melt manner, the corresponding two fusion layers 120 on the two adjacent pole tabs 11 fuse to achieve the corresponding two support layers 121 in the same composite structure 12 to fit together, and after further heating to the melting point of the support layer 121, the two adjacent pole tabs 11 are fused through the aforementioned two support layers 121 to form a polymer 13. Obviously. This combination makes the structure of the polymer 13 formed by fusion more stable (compared to the polymer 13 formed by the scheme of embodiment 1).

[0056] Implementation method 5

[0057] Combination Fig.10 and Fig.11, the difference between this embodiment and embodiment 4 is that the fusion layer 120 is located between the corresponding pole ear 11 and the support layer 121 in the same composite structure 12. After the pole ear connection structure 1 is heated to the melting point of the fusion layer 120 in a hot melt manner, the two fusion layers 120 in the two adjacent composite structures 12 are respectively fused to the corresponding two pole ears 11, and after further heating to the melting point of the support layer 121, the two support layers 121 in the two adjacent composite structures 12 are fused to achieve the fusion of the two adjacent pole ears 11 with the corresponding two fusion layers 120 to form a polymer 13. Obviously. This combination makes the structure of the polymer 13 formed by fusion more stable (compared to the polymer 13 formed by the scheme of embodiment 1).

[0058] Implementation 6

[0059] Combination Fig.12 and Fig.13 , the difference between this embodiment and embodiment 5 is that the composite structure 12 includes a support layer 121 and two fusion layers 120. Among them, the support layer 121 is located between the two fusion layers 120 (refer to the above). After the pole ear connection structure 1 is heated to the melting point of the fusion layer 120 in a hot melt manner, the two first fusion layers 1200 in the two adjacent composite structures 12 are respectively fused to the corresponding two pole ears 11, and the two second fusion layers 1201 are fused to achieve the two support layers 121 in the same composite structure 12 to fit each other. After continuing to heat to the melting point of the support layer 121, the two support layers 121 in the two adjacent composite structures 12 are fused to achieve the fusion of the two adjacent pole ears 11 with the corresponding two fusion layers 120 to form a polymer 13. Obviously. This combination method makes the structure of the polymer 13 formed by fusion more stable (compared with the polymer 13 formed by the scheme of embodiment 1). It should be noted that the positions of the first fusion layer 1200 and the second fusion layer 1201 are not limited.

[0060] The above is only a preferred specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A tab connection structure, Features: It includes a plurality of pole ears electrically connected to the electrode sheets, each of the pole ears is fixedly connected to at least one composite structure, the composite structure includes a support layer and at least one fusion layer, the melting point of the fusion layer is lower than the melting point of the support layer, the fusion layers of the composite structure on each two adjacent pole ears are hot-melt connected to form an aggregate, and the pole ears are fixedly connected to the fusion layer.

2. The tab connection structure according to claim 1, Features: Each of the composite structures comprises at least one fusion layer, and the fusion layer is fixedly connected to the lower surface of the uppermost tab among the plurality of tabs; the fusion layer is fixedly connected to the upper surface of the lowermost tab among the plurality of tabs; The fusion layer is fixedly connected to the upper surface and / or the lower surface of each of the tabs located in the middle.

3. The tab connection structure according to claim 1, Features: The upper and lower surfaces of the support layer are respectively in contact with the tab and the fusion layer.

4. The tab connection structure according to claim 1, Features: The upper and lower surfaces of the fusion layer are respectively in contact with the tab and the support layer.

5. The tab connection structure according to claim 4, Features: The number of the fusion layers is two, and the support layer is located between the two fusion layers.

6. The tab connection structure according to claim 1, Features: The ratio of the thickness of the support layer to the thickness of the fusion layer is 1:

3.

7. The tab connection structure according to claim 2, Features: The melting point of the fusion layer is between 100°C and 120°C.

8. The tab connection structure according to claim 1, Features: The melting point of the support layer is between 100°C and 160°C.

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