Connecting piece and battery cell

Abstract

The invention relates to the technical field of batteries, in particular to a connecting piece and a battery cell. The connecting piece is provided with a first connecting part and a second connecting part which are respectively used for connecting the tab and the pole, a sunken thinning groove is formed between the first connecting part and the second connecting part, the connecting piece is bent to enable the first connecting part and the second connecting part to be close to each other to form a bent part, and the thinning groove is formed in the bent part; 0.2 < = h / t < = 0.8, 1 < = w / t < = 5. According to the invention, the thinning groove is formed to position and guide the bent connecting sheet in the bending process, and the relationship between the size of the thinning groove and the thickness size of the connecting sheet is limited, so that the overall structural strength of the connecting sheet is ensured while the over-current heating requirement is met, the situation that the connecting sheet is deformed or fractured in the working condition is avoided, and the service life of the connecting sheet is prolonged. And the condition of extrusion cracking in the process of bending the connecting sheet caused by too small slotting size is avoided while the reliable positioning and guiding effects of the thinning groove are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a connecting piece and an electric core. Background Art

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the use performance and safety of lithium-ion batteries are increasing day by day. The traditional four-pole group square lithium battery structure includes a cover plate, a housing and a pole group. The cover plate and the housing are welded and sealed to encapsulate the pole group inside. The pole group is connected to the positive and negative connecting pieces through the positive and negative pole tabs, and then the connecting piece is welded to the bottom plate of the cover plate pole column to form the positive and negative poles leading to the outside of the electric core. The connecting piece needs to be bent to be encapsulated in the housing. The existing connecting piece is provided with a through hole at the bent portion to facilitate bending, but it will affect the structural strength and current-carrying heat generation of the connecting piece. In addition, the bent connecting piece occupies a large internal space of the electric core, affecting the capacity of the electric core, and the positioning accuracy is poor, which easily causes the gap between the bent connecting piece and the housing to be too small and trigger a short-circuit risk. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a connecting piece and an electric core to solve the problem that the existing connecting piece is provided with a through hole at the bent portion, which affects the structural strength of the connecting piece and cannot meet the requirements of current-carrying heat generation, and the positioning accuracy of the bent connecting piece is poor, which easily triggers the short-circuit risk of the electric core.

[0004] The first aspect of the present invention provides a connecting piece, wherein the connecting piece has a first connecting portion and a second connecting portion respectively used for connecting the pole tab and the pole column. A concave thinning groove is provided between the first connecting portion and the second connecting portion. The connecting piece is bent so that the first connecting portion and the second connecting portion approach each other to form a bent portion, and the thinning groove is arranged in the bent portion; 0.2≤h / t≤0.8, 1≤w / t≤5; wherein, h is the thickness dimension of the area of the connecting piece where the thinning groove is provided, in mm; w is the width dimension of the thinning groove, in mm; t is the thickness dimension of the first connecting portion or the second connecting portion, in mm.

[0005] Preferably, 0.25mm≤h≤3mm.

[0006] Preferably, 0.3mm≤t≤3mm.

[0007] Preferably, 0.3mm≤w≤10mm.

[0008] Preferably, the bent portion is bent into an arc shape, and the radius of the bent portion is R, 1≤R / t≤3.

[0009] Preferably, 0.25 mm ≤ R ≤ 10 mm.

[0010] Preferably, a positioning hole is formed in the connecting piece, and the distance between the thinning groove and the positioning hole before bending is k, where 0.5 mm ≤ k ≤ 30 mm.

[0011] Preferably, the first connecting portion and the second connecting portion are arranged in parallel, and / or the connecting piece is formed into an L-shaped sheet structure before bending, and / or the thinning groove is formed into a strip structure extending to the edge of the connecting piece.

[0012] Preferably, the bent connecting piece is installed inside the battery cell housing, and in the thickness direction of the battery cell housing, the distance between the connecting piece and the battery cell housing is g, where 0.5 mm ≤ g ≤ 30 mm.

[0013] The second aspect of the present invention provides a battery cell, including the connecting piece according to any one of the above technical solutions.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] The connecting piece of the present invention has a first connecting portion and a second connecting portion respectively for connecting the tab and the terminal post. A concave thinning groove is provided between the first connecting portion and the second connecting portion. The connecting piece is bent so that the first connecting portion and the second connecting portion are close to each other to form a bent portion, and the thinning groove is provided in the bent portion to realize the positioning and guiding of the bent connecting piece during the bending process, ensuring that the connecting piece is bent into the required shape structure; by defining that the relationship between the size of the thinning groove and the thickness size of the connecting piece satisfies 0.2 ≤ h / t ≤ 0.8 and 1 ≤ w / t ≤ 5, while meeting the overcurrent heating requirements, the overall structural strength of the connecting piece is ensured, avoiding deformation or fracture of the connecting piece under working conditions, and while ensuring the reliable positioning and guiding function of the thinning groove, avoiding the situation of material extrusion and cracking during the process of bending the connecting piece due to too small slotting size.

[0016] In order to make the above objects, features, and advantages of the present application more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, makes the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1Schematic diagram of the structure of the connecting piece provided by the embodiment of the present invention;

[0019] Figure 2 Is along Figure 1 Cross-sectional view taken along A-A in;

[0020] Figure 3 Is Figure 2 Enlarged schematic diagram of the structure at F in;

[0021] Figure 4 Schematic diagram of the structure of the connecting piece assembled in the battery cell provided by the embodiment of the present invention;

[0022] Figure 5 Is along Figure 4 Cross-sectional view taken along C-C in;

[0023] Figure 6 Is along Figure 5 Cross-sectional view taken along D-D in;

[0024] Figure 7 Is Figure 6 Enlarged schematic diagram of the structure at E in.

[0025] Icon: 10 - connecting piece; 11 - first connecting part; 12 - second connecting part; 13 - thinning groove; 14 - positioning hole; 101 - bending part; 20 - electrode group; 21 - tab; 30 - battery cell cover plate; 31 - terminal; 32 - positioning pin; 40 - battery cell housing. Detailed implementation manners

[0026] The following detailed implementation manners are provided to assist the reader in obtaining a comprehensive understanding of the methods, devices, and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein. Rather, changes that will be apparent after understanding the disclosure of the present application may be made, except for operations that must occur in a specific order. In addition, descriptions of features known in the art may be omitted for the sake of clarity and conciseness.

[0027] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many possible ways of implementing the methods, devices, and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0028] Throughout the specification, when an element such as a layer, region, or substrate is described as being "on" another element, "connected to" another element, "coupled to" another element, "above" another element, or "covering" another element, it can be directly "on" the other element, "connected to" the other element, "coupled to" the other element, "above" the other element, or "covering" the other element, or there can be one or more other elements intervening therebetween. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly coupled to" another element, "directly above" another element, or "directly covering" another element, there can be no other elements intervening therebetween.

[0029] As used herein, the term "and / or" includes any one of the listed related items and any combination of any two or more of them.

[0030] Although terms such as "first", "second", and "third" may be used herein to describe various components, elements, regions, layers, or sections, these components, elements, regions, layers, or sections are not limited by these terms. Rather, these terms are only used to distinguish one component, element, region, layer, or section from another. Thus, the first component, element, region, layer, or section described in the examples herein may also be referred to as the second component, element, region, layer, or section without departing from the teachings of the examples.

[0031] For ease of description, spatial relationship terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another as shown in the figures. Such spatial relationship terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as "above" or "upper" relative to another element will then be "below" or "lower" relative to the other element. Thus, the term "above" includes both the orientations of "above" and "below" depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relationship terms used herein will be interpreted accordingly.

[0032] The terms used herein are for the purpose of describing various examples only and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. The terms "comprising", "including" and "having" enumerate the stated features, quantities, operations, components, elements and / or combinations thereof that exist, but do not preclude the existence or addition of one or more other features, quantities, operations, components, elements and / or combinations thereof.

[0033] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Accordingly, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing.

[0034] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible, as will be apparent after understanding the disclosure of the present application.

[0035] According to a first aspect of the present invention, a connecting piece is provided.

[0036] Hereinafter, the specific structure of the connecting piece according to the present embodiment will be described.

[0037] In the present embodiment, as Figures 1 to 3As shown in the figure, the connecting piece 10 is formed into a sheet-like structure of metal, and has a first connecting portion 11 and a second connecting portion 12 respectively for connecting the tab 21 on the electrode group 20 and the terminal 31 on the battery cell cover plate 30. A recessed thinning groove 13 is provided between the first connecting portion 11 and the second connecting portion 12 to play a guiding role in bending the connecting piece 10. The connecting piece 10 is bent so that the first connecting portion 11 and the second connecting portion 12 are close to each other to form a bent portion 101 on the connecting piece 10. The thinning groove 13 is provided in the bent portion 101; in this embodiment, 0.2≤h / t≤0.8, 1≤w / t≤5; where h is the thickness dimension of the area of the connecting piece 10 where the thinning groove 13 is provided, in mm; w is the width dimension of the thinning groove 13, in mm; t is the thickness dimension of the first connecting portion 11 or the second connecting portion 12. When the thickness dimensions of the first connecting portion 11 and the second connecting portion 12 are the same, t is the thickness dimension of the remaining positions of the connecting piece 10 except the thinning groove 13, in mm. In this way, it is ensured that the thinning groove 13 has a certain groove depth and groove width, which is convenient for bending the connecting piece 10 while meeting the current-carrying requirement, so that the thinning groove 13 plays an effective positioning and guiding role, ensuring that the connecting piece 10 is bent into the required shape structure, and ensuring that the connecting piece 10 has sufficient strength. It is avoided that the parameter of h / t is too small, resulting in too low strength of the bent portion 101, which is prone to deformation or fracture under working conditions, and it is also avoided that the parameter of w / t is too small, resulting in cracking due to material extrusion in the thinning groove 13 during the bending process of the connecting piece 10, or avoiding that the parameter of w / t is too large, resulting in poor positioning accuracy, and the connecting piece 10 is prone to lap with the battery cell housing 40 after bending, causing a short-circuit risk.

[0038] Preferably, the thickness dimensions of the first connecting portion 11 and the second connecting portion 12 are equal, so that the connecting piece 10 is formed into an integral sheet-like structure, and there is no need to assemble the first connecting portion 11 and the second connecting portion 12 with different thicknesses.

[0039] In this embodiment, the thinning groove 13 is preferably formed into a strip-shaped structure, so that the connecting piece 10 is bent according to the position and extension shape of the thinning groove 13, with high positioning accuracy, effectively avoiding the short-circuit risk of too small clearance between the connecting piece 10 and the battery cell housing 40 after bending. The thinning groove 13 can be a rectangular groove-like structure. Further, both ends of the thinning groove 13 in the length direction extend to the edge of the connecting piece 10, so as to facilitate the bending of the connecting piece 10 and avoid local material extrusion during the bending process.

[0040] Preferably, in this embodiment, as Figure 3 shown, 0.25mm≤h≤3mm, ensuring that opening the thinning groove 13 does not affect the structural strength of the connecting piece 10, and can deform along the shape of the thinning groove 13 during the bending process of the connecting piece 10, improving the reliability of the positioning and guiding function of the thinning groove 13.

[0041] Preferably, in this embodiment, as Figure 3 shown, 0.3 mm ≤ t ≤ 3 mm, so as to ensure that the connecting piece 10 has sufficient mechanical strength and avoid the connecting piece 10 being too thick to be bent easily or occupying too much internal space of the battery core, which affects the energy density of the battery core.

[0042] Preferably, in this embodiment, as Figure 3 shown, 0.3 mm ≤ w ≤ 10 mm, which ensures that the thinning groove 13 has a good positioning and guiding effect, and at the same time avoids the bending part 101 being cracked due to material extrusion caused by too small a size of w.

[0043] Preferably, in this embodiment, the material of the connecting piece 10 is soft aluminum or soft copper in the O state for easy bending.

[0044] Preferably, as Figures 4 to 7 shown, after the connecting piece 10 is bent, the thinning groove 13 is arranged on the inner side of the connecting piece 10, so as to ensure that the outside of the connecting piece 10 is smooth and avoid scratching the pole ear 21 or the insulating film, etc.

[0045] In this embodiment, as Figure 7 shown, the bending part 101 is bent into an arc shape, the radius of the bending part 101 is R, 1 ≤ R / t ≤ 3, so as to avoid the bending part 101 being too sharp and cracked due to too small a size of R / t, and also avoid the size of R / t being too large to occupy the internal space of the battery core and affect the energy seal of the battery core. Preferably, 0.25 mm ≤ R ≤ 10 mm.

[0046] In this embodiment, as Figure 2 shown, the first connecting part 11 and the second connecting part 12 are arranged in parallel, that is, the first connecting part 11 and the second connecting part 12 are not coplanar before the connecting piece 10 is bent, so as to ensure that after the connecting piece 10 is bent, while the bending part 101 has a sufficient bending radius R, the distance between the first connecting part 11 and the second connecting part 12 is smaller, so that the distance between the pole column 31 and the pole ear 21 is smaller, and thus the volume of the electrode group 20 can be appropriately increased to improve the energy density of the battery core.

[0047] In this embodiment, as Figure 7 shown, in the thickness direction of the battery core cover plate 30, the maximum distance between the first connecting part 11 and the second connecting part 12 after bending is P. In this application, P ≈ R - 2×(t - h), while the maximum distance after bending of the traditional connecting piece is the size of R in this application. Therefore, the structure of the connecting piece 10 in this application can effectively save the occupied space in the battery core housing 40, thereby improving the space utilization rate inside the battery core and further improving the battery core capacity.

[0048] In this embodiment, as Figure 1As shown, before bending, the connecting piece 10 is formed into an L-shaped sheet structure, such that the first connecting portion 11 and the second connecting portion 12 are arranged at an angle, which facilitates the connection of the connecting piece 10 with the tab 21 and the terminal post 31, and avoids interference caused by too small an assembly space.

[0049] In this embodiment, as Figure 1 and Figure 7 shown, a positioning hole 14 is formed in the connecting piece 10. The positioning hole 14 is a through-hole structure penetrating the connecting piece 10. An insulating member is arranged on the side of the cell cover plate 30 facing the inside of the cell, and a positioning pin 32 extending into the positioning hole 14 is formed on the insulating member. In this way, the position of the connecting piece 10 relative to the cell cover plate 30 is fixed, so that the position of the connecting piece 10 in the cell housing 40 is fixed after the cell cover plate 30 and the cell housing 40 are assembled. In this embodiment, as Figure 1 shown, the distance between the thinning groove 13 and the positioning hole 14 before bending is k, where 0.5 mm ≤ k ≤ 30 mm. In this way, it is convenient to form the positioning hole 14 by stamping, and it will not affect the connection between the first connecting portion 11 and the second connecting portion 12 and the tab 21 and the pole group 20 respectively, and also avoids affecting the shape or size of the thinning groove 13 during the formation of the positioning hole 14.

[0050] Specifically, in this embodiment, as Figure 1 shown, a plurality of positioning holes 14 are provided. The plurality of positioning holes 14 are arranged at intervals along the length direction of the thinning groove 13, so as to ensure reliable position positioning of the connecting piece 10.

[0051] In this embodiment, as Figure 7 shown, the bent connecting piece 10 is installed inside the cell housing 40. In the thickness direction of the cell housing 40 (i.e., the width direction of the cell cover plate 30), the distance between the connecting piece 10 and the cell housing 40 is g, where 0.5 mm ≤ g ≤ 30 mm, to avoid an increased risk of short circuit caused by too small a size of g resulting in the overlap of the connecting piece 10 and the cell housing 40.

[0052] Next, cells assembled with connecting pieces 10 of different sizes are measured for the parameters of t, h, w, R1, and g to inspect the assembly quality of the cells and the situation after the cells are used for a period of time. The specific test results are shown in the following table:

[0053]

[0054]

[0055] Note: " / " in the table indicates that no failure mode is found, indicating that the assembly quality of the cell is qualified and it has good performance in use.

[0056] Referring to the above table, it can be seen that in Examples 1 to 5, all parameters are within the defined range, the cell assembly quality is qualified and has good performance; while in Example 6, the main reason for the bending deformation of the connecting piece 10 not occurring according to the structure of the thinning groove 13 is that the parameter of h / t is too large; in Example 7, the main reason for the serious deformation of the bending part of the cell after being used for a period of time is that the parameter of h / t is too small; in Example 8, the problem that the connecting piece 10 does not bend and deform according to the structure of the thinning groove 13 and deviates too much, resulting in a short-circuit abnormality of the cell and too small a gap between the connecting piece 10 and the cell housing 40, and the reason for the current arcing is that the parameter of w / t is too large and the parameter of g is too small; in Example 9, the main reason for the cracking of the bending part is that the parameter of w / t is too small; in Example 10, the main reason for the cracking of the bending part is that the parameter of R1 / t is too small.

[0057] A connecting piece provided according to the present invention has a first connecting part and a second connecting part respectively for connecting a tab and a terminal post. A recessed thinning groove is provided between the first connecting part and the second connecting part. The connecting piece is bent so that the first connecting part and the second connecting part are close to each other to form a bending part, and the thinning groove is provided in the bending part to realize the positioning and guiding of the bent connecting piece during the bending process, ensuring that the connecting piece is bent into the required shape structure; by defining that the relationship between the size of the thinning groove and the thickness size of the connecting piece satisfies 0.2 ≤ h / t ≤ 0.8 and 1 ≤ w / t ≤ 5, thus while meeting the overcurrent and heat generation requirements, the overall structural strength of the connecting piece is ensured, avoiding the deformation or fracture of the connecting piece under working conditions, and while ensuring the reliable positioning and guiding function of the thinning groove, avoiding the situation of material extrusion and cracking during the process of bending the connecting piece due to too small a slot size.

[0058] A cell provided according to the present invention includes the connecting piece as described above. The thinning groove can play a role in guiding and positioning the bending of the connecting piece, enabling the connecting piece to be bent into the required shape structure inside the cell, ensuring that there is enough clearance between the connecting piece and the housing, reducing the short-circuit risk, and ensuring the safety performance of the cell.

[0059] Finally, it should be noted that the above-described embodiments are only specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, rather than limiting it. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that any person skilled in the art within the technical scope disclosed by the present application can still modify the technical solutions recorded in the foregoing embodiments or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A connecting sheet, characterized in that: The connecting piece has a first connecting portion and a second connecting portion for connecting the pole lug and the pole respectively, a recessed thinning groove is arranged between the first connecting portion and the second connecting portion, the connecting piece is bent so that the first connecting portion and the second connecting portion are close to each other to form a bending portion, and the thinning groove is arranged at the bending portion; 0.2≤h / t≤0.8, 1≤w / t≤5; wherein h is the thickness dimension of the area on the connecting piece where the thinning groove is arranged, in mm; w is the width dimension of the thinning groove, in mm; t is the thickness dimension of the first connecting portion or the second connecting portion, in mm.

2. The connecting piece according to claim 1, characterized in that: 0.25mm≤h≤3mm.

3. The connecting sheet according to claim 1, characterized in that: 0.3mm≤t≤3mm.

4. The connecting sheet according to claim 1, characterized in that: 0.3mm≤w≤10mm.

5. The connecting sheet according to claim 1, characterized in that: The bending portion is bent into an arc shape, and the radius of the bending portion is R, 1≤R / t≤3.

6. The connecting piece according to claim 5, characterized in that: 0.25mm≤R≤10mm.

7. The connecting sheet according to claim 1, characterized in that: A positioning hole is provided on the connecting piece, and the distance between the thinning groove and the positioning hole before bending is k, 0.5mm≤k≤30mm.

8. The connecting sheet according to claim 1, characterized in that: The first connecting portion and the second connecting portion are arranged in parallel, and / or the connecting sheet is formed into an L-shaped sheet structure before bending, and / or the thinning groove is formed into a strip structure extending to the edge of the connecting sheet.

9. The connecting sheet according to claim 1, characterized in that: The bent connecting piece is installed inside the battery cell shell. In the thickness direction of the battery cell shell, the distance between the connecting piece and the battery cell shell is g, and 0.5 mm≤g≤30 mm.

10. A battery cell, characterized in that: The connecting piece comprises the connecting piece according to any one of claims 1 to 9.

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