Roll core structure and battery core

Abstract

The invention provides a roll core structure and a battery cell, and belongs to the field of battery cells, and the roll core structure comprises a first roll core, one end face of the second roll core is a second step; a pole assembly; the first step and the second step are two end surfaces, facing the same direction, of the first roll core and the second roll core; the end face, back to the first step, of the first roll core is flush with the end face, back to the second step, of the second roll core, and a height difference exists between the first step and the second step. And the pole assembly is arranged on the lower step. The step structure with the height difference is formed at the tops of the two roll cores, so that the pole assembly is arranged at the low step position at the top under the condition that the bottoms of the two roll cores are kept flush, the pole assembly does not occupy the height of the roll cores, the height of one roll core can be maximized, the amount of the wound active material is reduced, and the production efficiency is improved. And finally, the cell energy density is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery cells, in particular to a winding core structure and a battery cell. BACKGROUND

[0002] At present, with the expansion of the market scale of battery cells, the competition among manufacturers is increasingly fierce. In order to stand out in the fierce market competition, product quality and price are the main factors. On the one hand, the conventional riveting, injection molding, and spin riveting have complex structures and high costs, making it difficult to further reduce the cost of battery cells. On the other hand, the conventional riveting and injection molding top cover occupy a lot of height space of the battery cell itself, limiting the height of the winding core of the battery cell, i.e. limiting the energy density of the battery cell.

[0003] Chinese patent CN219226449U discloses a square shell battery cell. The pole post of the top of this type of battery cell will protrude and be higher than the top cover of the battery cell. Therefore, during the PACK assembly or stacking and storage process of the battery cell, the protruding part of the pole post will occupy a certain space. Therefore, in order to improve the competitiveness of the product, a battery cell with a simple structure, low cost, and higher space utilization needs to be designed. SUMMARY

[0004] Therefore, the present application provides a winding core structure and a battery cell to solve the problem of low space utilization of the battery cell.

[0005] The technical solution of the present application is as follows: The present application provides a winding core structure, which comprises a first winding core, one end face of which is a first step; a second winding core, one end face of which is a second step; and a pole post assembly; wherein the first step and the second step are two end faces of the first winding core and the second winding core facing the same direction; the end face of the first winding core facing away from the first step is flush with the end face of the second winding core facing away from the second step, and there is a height difference between the first step and the second step; and the pole post assembly is arranged on the step with lower height.

[0006] On the basis of the above technical solution, preferably, the first winding core and the second winding core are respectively provided with a first tab and a second tab, the first tab and the second tab are respectively located on the first step and the second step, and the ends of the first tab and the second tab are arranged in overlap and connected with the pole post assembly.

[0007] Further preferably, when the first step is higher than the second step, the first tab is bent away from the second step, the second tab is bent away from the second step, the bent shape of the second tab matches the step structure formed by the first step and the second step, and the ends of the first tab and the second tab overlap on the first step.

[0008] Further preferably, the connecting piece is connected to the end of the first and second tabs, and the other end of the connecting piece extends to the second step and is connected to the pole assembly.

[0009] Further preferably, the pole assembly comprises a positive pole and a negative pole, and the positive pole and the negative pole are arranged on the second step.

[0010] On the basis of the above technical scheme, preferably, the first step and the second step have the same area.

[0011] On the basis of the above technical scheme, preferably, the first winding core and the second winding core have the same width and thickness.

[0012] On the basis of the above technical scheme, preferably, the first winding core and the second winding core have the same width and thickness.

[0013] On the basis of the above technical scheme, preferably, the first winding core and the second winding core have the same width and thickness.

[0014] On the basis of the above technical scheme, preferably, the first winding core and the second winding core have the same width and thickness.

[0015] The winding core structure and the battery cell of the present application have the following advantages over the prior art: (1) The present application adopts two winding cores to form a step structure with a height difference at the top, so that the two winding cores can be kept flush at the bottom, and the pole assembly is arranged at the low step position at the top, so that the pole assembly does not occupy the height of the winding core, and one of the winding cores can be maximized in height, so as to maximize the amount of active material wound, and finally improve the energy density of the battery cell.

[0016] (2) In the present application, both tabs are bent to overlap the high step surface and then connected to the connecting piece, so that the conductive path of the tab is reduced, and the tab is directly connected to the pole assembly in the shortest path, and the number and complexity of the welding points are reduced, which is beneficial to improve the stability and consistency of the winding core; the tab bending structure fits the shape of the step, so that the tab arrangement is more compact and the current flow is more uniform, and the heat is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0018] Figure 1 It is a perspective view of the battery cell of the present application. Figure 2 It is a perspective view of the winding core structure of the present application. Figure 3 It is an exploded perspective view of the winding core structure of the present application. Figure 4 It is an enlarged view of the step structure of the winding core structure of the present application.

[0019] In the figure: 1, first winding core; 11, first tab; 101, first step; 2, second winding core; 21, second tab; 201, second step; 3, pole assembly; 31, positive pole; 32, negative pole; 4, connecting piece; 5, shell; 6, cover plate; 61, explosion-proof valve; 62, liquid injection hole. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will combine the drawings in the present application to clearly and completely describe the technical solutions in the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0022] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0023] 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 invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0026] like Figure 1 As shown, combined with Figure 2 and Figure 4 The present invention provides a core structure comprising a first core 1, a second core 2, and a pole assembly 3.

[0027] In this embodiment, one end face of the first core 1 is the first step 101; one end face of the second core 2 is the second step 201; the first step 101 and the second step 201 are the two end faces of the first core 1 and the second core 2 facing the same direction; both the first core 1 and the second core 2 are core structures obtained by winding core material, so the difference between this embodiment and the currently common single-core battery cell is the use of a double-core structure; the first core 1 and the second core 2 are tightly attached to each other, and a Mylar film is sandwiched between their surfaces. When the other two end faces of the first core 1 and the second core 2, that is, when the end face of the first core 1 facing away from the first step 101 and the end face of the second core 2 facing away from the second step 201 are flush, there is a height difference between the first step 101 and the second step 201. Specifically, when the bottom surfaces of the two cores are flush, the heights of the two cores will differ, resulting in a step-like structure with a height difference on the top surfaces of the two cores.

[0028] The electrode assembly 3 is positioned on a lower step, utilizing the extra space provided by the lower step to increase the vertical space margin for its installation. This prevents the outer end of the electrode assembly 3 from protruding from the overall structure of the battery cell, allowing the outer contour of the battery cell to form a shape similar to an ideal square column. When assembling or stacking the battery cells of this embodiment, the bottom of the upper cell can be closer to the higher step surface of the lower cell in two adjacent cells, without compressing the electrode assembly 3 located on the lower step and causing crush damage. This significantly improves the utilization rate of the top space of the entire battery cell, making the cell array more compact. Furthermore, compared to a single-core structure of the same height, one of the cores in the dual-core structure of this embodiment can achieve maximum height, thereby increasing the energy density of the battery cell.

[0029] exist Figure 3 In one embodiment shown, a first tab 11 and a second tab 21 are respectively provided on the first core 1 and the second core 2. The first tab 11 and the second tab 21 are independently led-out tab structures from the first core 1 and the second core 2, respectively, and their function is to connect the core and the terminal assembly. The first tab 11 and the second tab 21 are located on the first step 101 and the second step 201, respectively. The ends of the first tab 11 and the second tab 21 overlap and are simultaneously connected to the terminal assembly 3, making the current-carrying path of the two cores shorter and more uniform. This helps to reduce the internal resistance of the core and make the current distribution inside the cell more uniform, thereby improving the safety and lifespan of the cell.

[0030] exist Figure 3In one embodiment shown, when the first step 101 is higher than the second step 201, the height of the first core 1 will be greater than that of the second core 2. The first tab 11 bends away from the second step 201, and the second tab 21 also bends away from the second step 201. The lead-out length of the second tab 21 will be greater than that of the first tab 11. The bending shape of the second tab 21 matches the step structure formed by the first step 101 and the second step 201, forming a Z-shaped structure, so that the ends of the first tab 11 and the second tab 21 can overlap on the first step 101. The height difference between the first step 101 and the second step 201 is 2-6mm, thereby reserving space for other components such as the welding of the electrode plate, maximizing the utilization of the top space of the cell, and the tab, connecting piece 4, electrode post assembly 3, and electrode plate will be basically on the same horizontal plane. This not only achieves high space utilization at the cell level, but also achieves high space utilization at the module PACK level. Theoretically, a longer first tab 11 could be used, with both tabs bent toward the lower second step 201, and the ends of the two tabs overlapping on the second step 201. However, this design would encroach on the vertical space available for installing the pole assembly 3. Therefore, in this embodiment, the optimal solution is to have the two tabs overlap on the higher first step 101.

[0031] exist Figure 3 In one embodiment shown, a connecting piece 4 is also included. The connecting piece 4 serves as a current busbar between the tab and the terminal assembly 3. One end of the connecting piece 4 is connected to the ends of both the first tab 11 and the second tab 21, while the other end extends bent towards the second step 201. The other end of the connecting piece 4 is connected to the terminal of the terminal assembly 3 by seam welding or through welding. The bending shape of the connecting piece 4 matches the stepped structure formed by the first step 101 and the second step 201, roughly forming a Z-shape. The bending path of the connecting piece 4, in accordance with the stepped structure, maintains the compactness of the overall cell structure.

[0032] exist Figure 1 In one embodiment shown, the electrode assembly 3 includes a positive electrode 31 and a negative electrode 32, which are spaced apart on the second step 201; the first tab 11, the second tab 21 and the connecting piece 4 are all in two sets and are respectively connected to the positive electrode 31 and the negative electrode 32, so that the battery cell forms a standard bipolar output structure.

[0033] exist Figure 2 In one embodiment shown, the first step 101 and the second step 201 have the same area, which helps to ensure structural alignment when the cover plate 6 and the housing 5 are matched, improves the consistency of cell manufacturing, and facilitates the automation of the cell assembly line.

[0034] exist Figure 2In one embodiment shown, the width and thickness of the first core 1 and the second core 2 are the same, ensuring the overall shape of the double core structure is symmetrical, which is conducive to the uniform arrangement of the internal structure of the battery cell and improves the stability and mechanical strength of the battery cell.

[0035] like Figure 1 As shown, combined with Figure 2 The present invention provides a battery cell that adopts the winding core structure of any of the above embodiments and further includes a housing 5 and a cover plate 6.

[0036] The housing 5 is made of aluminum and has an open top end. The two cores are first covered with Mylar film and then inserted into the housing 5. The housing 5 contains a first core 1 and a second core 2. The shape of the top of the housing 5 and the cover plate 6 matches the stepped structure formed by the first step 101 and the second step 201.

[0037] The cover plate 6 is placed on the open end face of the housing 5. The cover plate 6 is also a plate structure similar to a Z-shape. The cover plate 6 also has two stepped surfaces with different heights. The pole post assembly 3 is set on the cover plate 6. Generally, two through holes are opened on the lower step surface of the cover plate 6, and the two pole post assemblies 3 are respectively inserted into the two through holes.

[0038] exist Figure 1 In one embodiment shown, the cover plate 6 is provided with an explosion-proof valve 61 and a liquid injection hole 62. The explosion-proof valve 61 and the liquid injection hole 62 are located on a higher step to avoid affecting the installation of the electrode assembly 3. The positions of the explosion-proof valve 61 and the liquid injection hole 62 can also be set on a lower step according to the actual situation. In this case, they are generally located between the positive electrode 31 and the negative electrode 32.

[0039] exist Figure 1 In one embodiment shown, the end face of the electrode assembly 3 away from the cover plate 6 is flush with the end face of the cover plate 6 with a higher height, making the top surface of the entire cell structure relatively flat, which is conducive to more compact pack stacking.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A core structure, characterized in that, include: The first core (1) has one end face as the first step (101); The second core (2) has one end face as the second step (201); pole assembly (3); Wherein, the first step (101) and the second step (201) are two end faces of the first core (1) and the second core (2) facing the same direction; the end face of the first core (1) facing away from the first step (101) and the end face of the second core (2) facing away from the second step (201) are flush, and there is a height difference between the first step (101) and the second step (201); the pole assembly (3) is set on the step with the lower height.

2. The core structure according to claim 1, characterized in that: The first core (1) and the second core (2) are respectively provided with a first pole tab (11) and a second pole tab (21). The first pole tab (11) and the second pole tab (21) are respectively located on the first step (101) and the second step (201). The ends of the first pole tab (11) and the second pole tab (21) overlap and are simultaneously connected to the pole post assembly (3).

3. The core structure according to claim 2, characterized in that: When the first step (101) is higher than the second step (201), the first tab (11) bends away from the second step (201), and the second tab (21) bends away from the second step (201). The bending shape of the second tab (21) matches the step structure formed by the first step (101) and the second step (201), and the ends of the first tab (11) and the second tab (21) overlap on the first step (101).

4. The core structure according to claim 3, characterized in that: It also includes a connecting piece (4), one end of which is connected to the ends of the first electrode (11) and the second electrode (21), and the other end of which extends to the second step (201) and is connected to the pole assembly (3). The bending shape of the connecting piece (4) matches the step structure formed by the first step (101) and the second step (201).

5. A core structure according to claim 4, characterized in that: The electrode assembly (3) includes a positive electrode (31) and a negative electrode (32). The positive terminal (31) and the negative terminal (32) are spaced apart on the second step (201); The first electrode (11), the second electrode (21) and the connecting piece (4) each have two sets and are respectively connected to the positive electrode post (31) and the negative electrode post (32).

6. The core structure according to claim 1, characterized in that: The first step (101) has the same area as the second step (201).

7. The core structure according to claim 1, characterized in that: The width and thickness of the first core (1) and the second core (2) are the same.

8. A battery cell, characterized in that: The core structure described in any one of claims 1 to 7 further includes, The shell (5) has an open top end face; A cover plate (6) is provided on the open end face of the housing (5); The housing (5) contains the first core (1) and the second core (2), and the top of the housing (5) and the cover plate (6) are shaped to match the step structure formed by the first step (101) and the second step (201); the cover plate (6) is provided with the pole post assembly (3).

9. A battery cell according to claim 8, characterized in that: The cover plate (6) is provided with an explosion-proof valve (61) and an injection hole (62), and the explosion-proof valve (61) and the injection hole (62) are located on a higher step.

10. A battery cell according to claim 8, characterized in that: The end face of the pole assembly (3) away from the cover plate (6) is flush with the end face of the cover plate (6) that is higher.

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