Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery. The battery cell and the battery relate to the technical field of new energy. The utility model discloses a battery cell and a battery. The battery cell comprises a plurality of first pole pieces and two second pole pieces, wherein the first pole pieces are laminated along the thickness direction of the battery cell; in the thickness direction of the battery cell, the two second pole pieces are located on the outer sides of the first pole pieces respectively, each second pole piece comprises a coating part and a first empty foil part, and the two first empty foil parts are located on the two sides of the coating part in the first direction respectively; and on the same side of the battery cell along the first direction, the first empty foil parts of the two second pole pieces are oppositely bent and connected to form a limiting structure surrounding each first pole piece. According to the battery cell, the use of gummed paper is avoided, and the size of the battery cell can be further reduced in the stacking direction, so that the battery cell has higher energy density.

Description

Technical Field

[0001] This utility model relates to the field of new energy technology, and in particular to a battery cell and battery. Background Technology

[0002] With the development of new energy technologies, further improving battery energy density has become a key focus for more and more battery manufacturers. The core component of a battery is the cell, which can be divided into wound cells and stacked cells based on different manufacturing processes and cell structures. Stacked cells are often formed by alternating layers of positive and negative electrode plates. To prevent relative displacement between adjacent positive and negative electrode plates during battery assembly and use, adhesive tape is often used to fix the stacked electrode plates around the outer periphery of the cell.

[0003] When applying the adhesive tape, its two ends are bonded to the outer peripheral surfaces of the top and bottom electrodes, respectively. However, after being applied to the outer peripheral surfaces of the electrodes, the adhesive tape protrudes from them, thus occupying space along the stacking direction of the cell and affecting the battery's energy density. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a battery cell that avoids the use of adhesive tape, can further reduce the size of the battery cell in the stacking direction, and thus has a higher energy density.

[0005] This utility model also proposes a battery having the above-mentioned battery cell.

[0006] The battery cell according to a first aspect embodiment of the present invention includes:

[0007] Multiple first electrode sheets are stacked along the thickness direction of the battery cell;

[0008] Two second electrode plates are located on the outside of the first electrode plate along the thickness direction of the battery cell. The second electrode plate includes a coated portion and a first empty foil portion. The two first empty foil portions are located on both sides of the coated portion along the first direction.

[0009] In this configuration, on the same side of the battery cell along the first direction, the first empty foil portions of the two second electrode sheets are bent toward each other and connected to form a restrictive structure that surrounds each of the first electrode sheets.

[0010] The battery cell according to the embodiments of this utility model has at least the following beneficial effects:

[0011] On the same side of the battery cell along the first direction, the first empty foil portion of the upper second electrode and the first empty foil portion of the lower second electrode are bent towards each other and connected, thereby forming a confining structure that surrounds the first electrode. This confining structure can effectively fix the battery cell and prevent displacement of the first electrode. At the same time, it replaces the use of adhesive tape and can further reduce the size of the battery cell in the thickness direction, thereby enabling the battery cell to have a higher energy density.

[0012] According to some embodiments of the present invention, the battery cell further includes an insulating member located on the side of the first empty foil portion near the first electrode sheet.

[0013] According to some embodiments of the present invention, the two first empty foil portions on the same side of the battery cell are spaced apart and connected by the insulating member.

[0014] According to some embodiments of the present invention, the thickness of the insulating element is 8 μm to 20 μm.

[0015] According to some embodiments of the present invention, the two first empty foil portions on the same side of the battery cell are overlapped and connected.

[0016] According to some embodiments of the present invention, the second electrode further includes an insulating coating, which is applied to the side of the first empty foil portion near the first electrode.

[0017] According to some embodiments of the present invention, the thickness of the insulating coating is 2 μm to 10 μm.

[0018] According to some embodiments of the present invention, the battery cell further has a second direction intersecting the first direction, and the dimensions along the second direction are equal to the dimensions of the first empty foil portion and the coated portion.

[0019] According to some embodiments of the present invention, the second electrode further includes at least one second empty foil portion, which is located on one side of the coating portion along the second direction. On the same side of the battery cell, the second empty foil portions of the two second electrodes are bent toward each other and connected, and the second direction intersects the first direction.

[0020] According to some embodiments of the present invention, the second electrode further includes at least two second empty foil portions, and the coating portion is provided with second empty foil portions on both sides along the second direction. The second electrode further includes electrode tabs, and the electrode tabs and one of the second empty foil portions are provided on the same side of the coating portion. Furthermore, the electrode tabs and the second empty foil portions are spaced apart.

[0021] According to some embodiments of the present invention, along the thickness direction of the battery cell, the size L of the first empty foil portion and the thickness T of the battery cell have the following relationship: 1mm≤L≤T.

[0022] The battery according to a second aspect embodiment of the present invention includes the battery cell mentioned in any of the above embodiments.

[0023] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0025] Figure 1 This is a schematic diagram of the structure of a battery cell in the prior art;

[0026] Figure 2 A top view of a battery cell in the prior art;

[0027] Figure 3 This is a schematic diagram of the structure of the second electrode sheet in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of the battery cell according to an embodiment of the present invention (two first empty foil portions on the same side of the battery cell are spaced apart);

[0029] Figure 5 This is a schematic diagram of the structure of the battery cell according to an embodiment of the present invention (two first empty foil portions on the same side of the battery cell are overlapped);

[0030] Figure 6 This is a schematic diagram of the structure of the battery cell according to an embodiment of the present invention (an insulating coating is provided on the inner side of the first empty foil portion);

[0031] Figure 7 This is a schematic diagram of the structure of the second electrode sheet in an embodiment of the present invention (which also includes a second empty foil portion);

[0032] Figure 8 for Figure 7 The second electrode is applied to the top view of the battery cell.

[0033] Figure label:

[0034] First electrode 100;

[0035] Second electrode 200; First empty foil portion 210; Coating portion 220; Insulating coating 230; Second empty foil portion 240; Electrode tab portion 250;

[0036] Insulating component 300;

[0037] 400g of adhesive tape; Detailed Implementation

[0038] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown 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 are only used to explain this utility model, and should not be construed as limiting this utility model.

[0039] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 utility model.

[0040] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0041] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0042] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] With the development of new energy technologies, further improving battery energy density has become a key focus for many battery manufacturers. The core component of a battery is the cell, which can be divided into wound cells and stacked cells based on different manufacturing processes and cell structures. Stacked cells are typically formed by alternating layers of positive and negative electrode plates. To prevent relative displacement between adjacent positive and negative electrode plates during battery assembly and use, such as… Figure 1 and Figure 2 As shown, after the electrode sheets are stacked, adhesive tape 400 is often used to wrap around the outer periphery of the stacked battery cell for fixation.

[0044] When the adhesive tape 400 is applied, its two ends are respectively adhered to the outer peripheral surfaces of the uppermost electrode and the lowermost electrode. However, after the adhesive tape 400 is applied to the outer peripheral surfaces of the electrodes, it protrudes from the outer peripheral surfaces, thus occupying space along the stacking direction of the cell and affecting the energy density of the battery.

[0045] To address the aforementioned problems, the first aspect of this application proposes a battery cell, such as... Figure 3 and Figure 4 As shown, the battery cell includes multiple first electrode plates 100 and two second electrode plates 200, with each first electrode plate 100 stacked along the thickness direction of the battery cell. Each first electrode plate 100 is coated with an active material layer on both sides; some first electrode plates 100 are positive electrode plates, and the remaining first electrode plates 100 are negative electrode plates. The positive and negative electrode plates are stacked and alternately arranged. Along the thickness direction of the battery cell, one second electrode plate 200 is located on one side of each first electrode plate 100, and the other second electrode plate 200 is located on the other side of each first electrode plate 100, as shown... Figure 4 The first electrode 100 shown is stacked in the vertical direction as an example, with one second electrode 200 located at the top of each first electrode 100 and the other second electrode 200 located at the bottom of each first electrode 100.

[0046] The second electrode 200 is typically a single-sided sheet, meaning that only the side facing the first electrode 100 is coated with an active material layer. In the prior art, the active material layer of the second electrode 200 completely covers the current collector. However, in this embodiment, the second electrode 200 includes a coating portion 220 and a first empty foil portion 210. The coating portion 220 is coated with an active material layer, while the first empty foil portion 210 is not coated with an active material layer. That is, in this embodiment, the active material layer of the second electrode 200 does not completely cover the current collector, but leaves blank areas.

[0047] More specifically, such as Figure 3As shown, the coating portion 220 is located in the middle region of the second electrode 200, and the two first empty foil portions 210 are respectively located on both sides of the coating portion 220 along a first direction. It should be noted that the first direction can be either the length direction or the width direction of the second electrode 200. The dimensions of the two first empty foil portions 210 along the first direction can be the same or different. Figure 4 As shown, the coating portion 220 of the second electrode 200 is stacked correspondingly with the first electrode 100. The first empty foil portion 210 of the second electrode 200 extends out from the stacked portion and is bent toward the first electrode 100. Since the second electrode 200 is provided at both the upper and lower ends of the battery cell, and on the same side of the battery cell along the first direction, the first empty foil portion 210 of the upper second electrode 200 and the first empty foil portion 210 of the lower second electrode 200 are bent toward each other and connected, thereby forming a restrictive structure that surrounds the first electrode 100. This restrictive structure can effectively fix the battery cell and prevent the displacement of the first electrode 100. At the same time, it replaces the use of adhesive tape 400, and can further reduce the size of the battery cell in the thickness direction, thereby making the battery cell have a higher energy density.

[0048] It should be noted that the "connection" in "the first empty foil portion 210 of the upper second electrode 200 and the first empty foil portion 210 of the lower second electrode 200 are bent toward each other and connected" can be as follows: Figure 5 The direct connection shown, or it could also be as follows: Figure 4 The indirect connection shown refers to the two first empty foil portions 210 on the same side being spaced apart and connected as a whole structure by other components such as the insulating member 300.

[0049] The second electrode 200 can be either a positive or negative electrode, depending on the application scenario of the battery cell. Since the second electrode 200 is disposed around the first electrode 100, which includes both a positive and a negative electrode, taking the second electrode 200 as a positive electrode as an example, the first empty foil portion 210 of the second electrode 200 may come into contact with the negative electrode in the first electrode 100, creating a short circuit risk. Therefore, in the embodiments of this application, such as... Figure 4 As shown, the battery cell also includes an insulating member 300, which is disposed on the side of the first empty foil portion 210 near the first electrode 100.

[0050] like Figure 4 As shown, the insulating member 300 can be attached to the inner side of the first empty foil portion 210 or to the outer periphery of each first electrode 100, thereby effectively isolating the first empty foil portion 210 from the first electrode 100. In addition, the coating portion 220 and the adjacent first electrode 100 are separated by a diaphragm, so there is no risk of short circuit between the first electrode 100 and the second electrode 200.

[0051] Furthermore, in addition to its insulating function, the insulating component 300 also serves to connect the first empty foil portion 210. For example... Figure 4 As shown, the upper first empty foil portion 210 and the lower first empty foil portion 210 are spaced apart and not directly connected. That is, the sum of the dimensions of the two first empty foil portions 210 on the same side along the thickness direction of the battery cell is less than the thickness of the battery cell. The insulating member 300 extends vertically and separates the first empty foil portion 210 from the first electrode 100. Furthermore, the upper end of the insulating member 300 is connected to the upper first empty foil portion 210, and the lower end of the insulating member 300 is connected to the lower first empty foil portion 210, thereby forming a complete confinement structure surrounding the outer periphery of the first electrode 100.

[0052] It is understandable that the insulating component 300 can be adhesive tape, with both ends capable of being bonded to the corresponding first empty foil portion 210. Alternatively, the insulating component 300 can be a plastic component, connected and fixed to the corresponding first empty foil portion 210 via heat pressing or snap-fit ​​connection. Alternatively, the insulating component 300 can be a metal component with an inner insulating coating 230, its outer wall surface used for welding to the corresponding first empty foil portion 210. The insulating component 300 can also have other configurations, which are not listed here. If the insulating component 300 is adhesive tape, its inner side can also be bonded to the first electrode 100 or the diaphragm, thereby fixing each first electrode 100 and further enhancing the overall structural stability of the battery cell. Furthermore, the thickness of the insulating component 300 is 8μm to 10μm to obtain better connection strength while reducing the impact on the battery cell size.

[0053] In other embodiments, two first empty foil portions 210 on the same side of the battery cell are overlapped and connected. Specifically, as shown in... Figure 5 As shown, the sum of the dimensions of the two first empty foil portions 210 along the thickness direction of the battery cell is greater than the thickness of the battery cell, so that after the two first empty foil portions 210 are bent towards each other, there is a partial overlap. The overlapping areas of the two first empty foil portions 210 are connected and fixed by welding, bonding or other methods to form a stable confinement structure.

[0054] In the foregoing embodiments, the battery cell includes a separate insulating element 300 to prevent a short circuit between the first empty foil portion 210 and the first electrode 100. In other embodiments, the second electrode 200 further includes an insulating coating 230, such as... Figure 6As shown, an insulating coating 230 is applied to the side of the first empty foil portion 210 near the first electrode 100. The insulating coating 230 can be an insulating material such as alumina or boehmite. Even if the first empty foil portion 210 comes into contact with the first electrode 100 during an impact collision, the insulating coating 230 can effectively prevent short circuits, ensuring cell safety. The thickness and material of the insulating coating 230 can be adjusted according to actual needs to adapt to usage requirements in different environments. Furthermore, the thickness of the insulating coating 230 is between 2 μm and 10 μm, so that the insulating coating 230 can effectively prevent short circuits while minimizing the impact on cell size.

[0055] It should be noted that in the existing technology, adhesive tape 400 is used for fixing. Since the outermost second electrode 200 is only coated on one side, it may warp and deform after being rolled during its production, affecting the contact between the second electrode 200 and the first electrode 100. While the adhesive tape 400 can restrain the deformation of the second electrode 200, there is still a risk of warping in areas where the adhesive tape 400 is not applied, affecting the cell's performance.

[0056] To suppress warping deformation of the second electrode 200, in this embodiment, the dimension of the first empty foil portion 210 along the second direction is equal to the dimension of the coated portion 220. It should be noted that the second direction intersects the first direction; preferably, the second direction is perpendicular to the first direction. In such cases... Figure 3 and Figure 4 In the illustrated embodiment, the first direction is the width direction of the battery cell, and the second direction is the length direction of the battery cell. When one first empty foil portion 210 is connected to another first empty foil portion 210, the deformation of the first electrode 100 is constrained. Since the length of the first empty foil portion 210 is equal to the length of the coating portion 220, the deformation of the entire first electrode 100 is restricted. This improves the flatness of the second electrode 200, enhances the contact between the second electrode 200 and the first electrode 100, improves battery cell performance, and mitigates the lithium plating problem of the second electrode 200 during cycling.

[0057] In some embodiments, such as Figure 7As shown, the second electrode 200 also includes at least one second empty foil portion 240, which is located on one side of the coating portion 220 along the second direction. It should be noted that the phrase "the second empty foil portion 240 is located on one side of the coating portion 220 along the second direction" is only to define the relative positional relationship between the second empty foil portion 240 and the coating portion 220. When there is only one second empty foil portion 240, it is located on one side of the coating portion 220 along the second direction. When there are multiple second empty foil portions 240, they can be located on one or both sides of the coating portion 220 along the second direction. On the same side of the battery cell, the second empty foil portions 240 of the two second electrode portions 200 are bent towards each other and connected.

[0058] For example, such as Figure 7 In the illustrated embodiment, each of the first electrode 100 and the second electrode 200 has a tab 250 at its upper end, and the tabs 250 of the same polarity are connected to achieve concentrated input and output of current. The lower end of the second electrode 200 is also provided with a second empty foil portion 240. The second empty foil portion 240 and the tab 250 can restrict the displacement of the first electrode 100 in the length direction to further improve the stability of the cell structure.

[0059] Furthermore, the second electrode 200 includes at least two second empty foil portions 240. Taking two second empty foil portions 240 as an example, Figure 7 As shown, the coating portion 220 has a second empty foil portion 240 on both sides along the second direction. If there are three second empty foil portions 240, one side of the coating portion 220 can have one second empty foil portion 240, and the other side can have two second empty foil portions 240 spaced apart. That is, the coating portion 220 needs to have at least one second empty foil portion 240 on both sides along the second direction. On the same side of the battery cell, the second empty foil portions 240 of the two second electrode plates 200 are bent towards each other and connected, thereby restricting the displacement of the first electrode plate 100 in the length direction of the battery cell.

[0060] For example Figure 7 and Figure 8 Taking the illustrated embodiment as an example, the first empty foil portion 210 is disposed in the width direction of the second electrode 200, restricting the first electrode 100 from both sides in the width direction. The second empty foil portion 240 is disposed in the length direction of the second electrode 200, restricting the first electrode 100 from both sides in the length direction, so as to make the entire cell structure more stable.

[0061] Furthermore, such as Figure 7As shown, a tab 250 is also provided on one side of the battery cell along its length. The tab 250 is formed by cutting a current collector and can concentrate the current of the current collector for output. The tab 250 and one of the second empty foil portions 240 are provided on the same side of the coating portion 220. During the cutting process of forming the tab 250, the second empty foil portion 240 is also cut and formed. The second empty foil portion 240 and the tab 250 are spaced apart, so that the connection of the second empty foil portions 240 of the two second electrodes 200 and the connection of the tabs 250 of each electrode of the same polarity do not interfere with each other.

[0062] It is understandable that battery cells have positive and negative tabs, such as... Figure 8 As shown, the second empty foil portion 240 can be located between the positive electrode tab and the negative electrode tab, or it can be located outside the positive electrode tab and the negative electrode tab.

[0063] Along the thickness direction of the battery cell, the dimension L of the first empty foil portion 210 has the following relationship with the thickness T of the battery cell: 1mm ≤ L ≤ T. If the dimension of the first empty foil portion 210 is less than 1mm, it cannot be effectively connected by the insulating member 300. If the dimension of the first empty foil portion 210 is greater than T, it will result in the first empty foil portion 210 being too long after bending, which wastes material and increases the volume of the battery cell, affecting the compactness of the overall structure.

[0064] To verify the technical effects of the embodiments of this application, the following comparative experiments were also conducted. The specific experimental parameters are shown in the table below, where ED represents energy density:

[0065] Using existing technology where laminated cells are fixed with 16μm adhesive tape as a comparative example, the cell's designed thickness is 4.5mm. Experimental results show that the scheme of arranging two first empty foil portions 210 at intervals along the cell's thickness direction and connecting them via an insulating component 300 has a significant effect on improving energy density.

[0066]

[0067]

[0068] Furthermore, after the battery cell underwent 500 cycles of 5C, it was disassembled. In Examples 1 to 4, the first electrode 100 (the first electrode is the negative electrode) corresponding to the second electrode 200 (the second electrode 200 is the positive electrode in the examples) did not exhibit lithium plating. In contrast, the negative electrode corresponding to the single-sided sheet in the comparative example exhibited lithium plating around its perimeter. This verifies that the battery cell in the embodiments of this application has good flatness and can effectively reduce the probability of lithium plating.

[0069] The second aspect of this application also proposes a battery comprising the cell described in any of the above embodiments. This battery can be a power battery or a 3C battery, and can be used in large machinery such as automobiles, or in small electronic devices such as mobile phones and laptops. Since this battery incorporates all the technical solutions of any of the above embodiments, it possesses the technical effects of the corresponding embodiments, which will not be repeated here.

[0070] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A battery cell, characterized in that, include: Multiple first electrode sheets are stacked along the thickness direction of the battery cell; Two second electrode plates are located on the outside of the first electrode plate along the thickness direction of the battery cell. The second electrode plate includes a coated portion and a first empty foil portion. The two first empty foil portions are located on both sides of the coated portion along the first direction. In this configuration, on the same side of the battery cell along the first direction, the first empty foil portions of the two second electrode sheets are bent toward each other and connected to form a restrictive structure that surrounds each of the first electrode sheets.

2. The battery cell according to claim 1, characterized in that, The battery cell also includes an insulating component located on the side of the first empty foil portion near the first electrode.

3. The battery cell according to claim 2, characterized in that, The two first empty foil portions on the same side of the battery cell are spaced apart and connected by the insulating member.

4. The battery cell according to claim 2, characterized in that, The thickness of the insulating element is 8 μm to 20 μm.

5. The battery cell according to claim 1, characterized in that, The two first empty foil portions on the same side of the battery cell are overlapped and connected.

6. The battery cell according to claim 5, characterized in that, The second electrode also includes an insulating coating applied to the side of the first empty foil portion near the first electrode.

7. The battery cell according to claim 6, characterized in that, The thickness of the insulating coating is 2 μm to 10 μm.

8. The battery cell according to claim 1, characterized in that, The battery cell also has a second direction intersecting the first direction, and the dimensions along the second direction are equal to the dimensions of the first empty foil portion and the coated portion.

9. The battery cell according to claim 1, characterized in that, The second electrode also includes at least one second empty foil portion, which is located on one side of the coating portion along the second direction. On the same side of the battery cell, the second empty foil portions of the two second electrodes are bent toward each other and connected, and the second direction intersects the first direction.

10. The battery cell according to claim 9, characterized in that, The second electrode also includes at least two second empty foil portions. The coating portion is provided with second empty foil portions on both sides along the second direction. The second electrode also includes electrode tabs. The electrode tabs and one of the second empty foil portions are provided on the same side of the coating portion, and the electrode tabs and the second empty foil portions are spaced apart.

11. The battery cell according to claim 1, characterized in that, Along the thickness direction of the battery cell, the dimension L of the first empty foil portion has the following relationship with the thickness T of the battery cell: 1mm≤L≤T.

12. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 11.

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