Electrode assembly and secondary battery

Abstract

The utility model provides an electrode assembly and a secondary battery. The electrode assembly comprises a battery cell group, the battery cell group comprises at least one battery cell, the top surface of the battery cell in a first direction is provided with a positive pole lug and a negative pole lug, all the battery cells are arranged along a second direction, and the electrode assembly further comprises a first binding piece, a second binding piece and a third binding piece which are respectively arranged on the battery cell group, a second binding member; any one of the third binding piece, the first binding piece, the second binding piece and the third binding piece is attached to at least three adjacent surfaces of the battery cell group, and at least part of any one surface of the battery cell group is covered by at least one of the first binding piece, the second binding piece and the third binding piece; and the second binding piece and the third binding piece are respectively overlapped with at least part of the first binding piece. According to the utility model, the problem in the prior art that the battery cell is easy to wrinkle due to poor stress consistency and uneven local stress is solved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to an electrode assembly and a secondary battery. Background Technology

[0002] A secondary battery typically consists of a cell, electrolyte, and casing. The positive and negative electrode materials are homogenized into a slurry and then coated, rolled, and slit to form positive and negative electrode sheets. These sheets, along with a separator, are then wound to form the cell. After cell formation, due to variations in incoming materials and manufacturing processes, the internal stress of the cell is often inconsistent and uneven. The negative electrode sheet is prone to wrinkling due to uneven stress, thus affecting cell performance. Furthermore, after assembling the cell, electrolyte, and casing into a secondary battery, uneven expansion of the negative electrode sheet during use can further cause wrinkling, severely impacting the battery's performance.

[0003] Therefore, existing technologies have the problem that battery cells are prone to wrinkling due to poor stress consistency and uneven local stress. Utility Model Content

[0004] The main purpose of this utility model is to provide an electrode assembly and a secondary battery to solve the problem that the battery cell in the prior art is prone to wrinkling due to poor stress consistency and uneven local stress.

[0005] To achieve the above objectives, according to one aspect of the present invention, an electrode assembly is provided, comprising a battery cell assembly, the battery cell assembly including at least one battery cell, the battery cell having a positive electrode tab and a negative electrode tab on its top surface in a first direction, and all the battery cells arranged along a second direction. The electrode assembly further includes: a first restraining member; a second restraining member; and a third restraining member respectively disposed on the battery cell assembly, any one of the first restraining member, the second restraining member, and the third restraining member being in contact with at least three adjacent surfaces of the battery cell assembly, at least a portion of any surface of the battery cell assembly being covered by at least one of the first restraining member, the second restraining member, and the third restraining member being respectively disposed overlapping at least a portion of the first restraining member.

[0006] Furthermore, the first binding member is wound around the battery cell assembly, and the first binding member is respectively attached to the surfaces of the battery cell assembly at both ends in the first direction and the surfaces of the battery cell assembly at both ends in the second direction; and / or the second binding member is wound around the battery cell assembly, and the second binding member is respectively attached to the surfaces of the battery cell assembly at both ends in the second direction and the surfaces of the battery cell assembly at both ends in the third direction; and / or the third binding member is respectively attached to the surfaces of the battery cell assembly at both ends in the second direction and the bottom surface of the battery cell assembly in the first direction.

[0007] Furthermore, there are multiple first restraint members, which are spaced apart along a third direction.

[0008] Furthermore, at least one first binding member is attached between the positive electrode tab and the negative electrode tab, on the side of the positive electrode tab away from the negative electrode tab, and on the side of the negative electrode tab away from the positive electrode tab, respectively.

[0009] Furthermore, along a third direction, the first restraint member and the central axis of the positive electrode tab have a first distance, the positive electrode tab has multiple positive electrode tabs, half the width of the connection between the positive electrode tab and the battery cell is the first width, and the difference between the first distance and the first width is not less than 5mm; and / or, along a third direction, the first restraint member and the central axis of the negative electrode tab have a second distance, the negative electrode tab has multiple negative electrode tabs, half the width of the connection between the negative electrode tab and the battery cell is the second width, and the difference between the second distance and the second width is not less than 5mm.

[0010] Furthermore, in the first direction, the second restraint member is positioned relative to the bottom surface of the battery cell assembly, close to the top surface of the battery cell assembly.

[0011] Furthermore, the battery cell has a straight section and a curved section, with the curved section disposed at both ends of the straight section along a third direction, and the projection of the third restraining member located within the projection of the straight section of the battery cell along a second direction.

[0012] Furthermore, the portion of the third restraint member that is in contact with the surfaces of the battery cell assembly at both ends in the second direction has a dimension of not less than 10 mm in the first direction.

[0013] Furthermore, the thickness of the second restraint and / or the thickness of the third restraint are greater than the thickness of the first restraint.

[0014] According to another aspect of the present invention, a secondary battery is provided, including the electrode assembly described above.

[0015] Applying the technical solution of this utility model, the electrode assembly in this application includes a cell group, which includes at least one cell. Each cell has a positive electrode tab and a negative electrode tab on its top surface in a first direction, and all the cells are arranged along a second direction. The electrode assembly also includes a first restraining member, a second restraining member, and a third restraining member respectively disposed on the cell group. Any one of the first, second, and third restraining members is in contact with at least three adjacent surfaces of the cell group. At least a portion of any surface of the cell group is covered by at least one of the first, second, and third restraining members, and the second and third restraining members respectively overlap at least a portion of the first restraining member.

[0016] When using the electrode assembly of this application, since it includes a cell assembly, a first restraining member, a second restraining member, and a third restraining member, and any one of the first, second, and third restraining members is in contact with at least three adjacent surfaces of the cell assembly, and at least a portion of any surface of the cell assembly is covered by at least one of the first, second, and third restraining members, all surfaces of the cell assembly can be restrained by the first, second, and third restraining members. This improves the overall stress consistency of the cell, ensures uniform stress on the electrode sheets, and thus prevents wrinkles from forming on the electrode sheets. Simultaneously, since the second and third restraining members overlap at least a portion of the first restraining member, the stability of the contact between each restraining member and the cell assembly can be effectively guaranteed. Therefore, the electrode assembly of this application effectively solves the problem in the prior art where cells are prone to wrinkling due to poor stress consistency and uneven local stress. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0018] Figure 1 A schematic diagram of the structure of an electrode assembly according to a specific embodiment of the present invention is shown;

[0019] Figure 2 It shows Figure 1 A top view of the electrode assembly;

[0020] Figure 3 It shows Figure 1 Side view of the electrode assembly;

[0021] Figure 4 It shows Figure 1 A bottom view of the electrode assembly.

[0022] The above figures include the following reference numerals:

[0023] 10. Battery cell assembly; 11. Battery cell; 111. Positive electrode tab; 112. Negative electrode tab; 20. First restraint component; 30. Second restraint component; 40. Third restraint component. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0027] To address the problem of wrinkles easily forming in existing battery cells due to poor stress consistency and uneven local stress, this application provides an electrode assembly and a secondary battery.

[0028] Furthermore, the secondary battery in this application has the following electrode assembly.

[0029] Meanwhile, in the following embodiments of this application, the first direction is the Z-axis direction, the second direction is the X-axis direction, and the third direction is the Y-axis direction.

[0030] like Figures 1 to 4 As shown, the electrode assembly in this application includes a cell group 10, which includes at least one cell 11. Each cell 11 has a positive electrode tab 111 and a negative electrode tab 112 on its top surface in the Z-axis direction, and all cells 11 are arranged along the X-axis direction. The electrode assembly also includes a first binding member 20, a second binding member 30, and a third binding member 40 respectively disposed on the cell group 10. Any one of the first binding member 20, the second binding member 30, and the third binding member 40 is in contact with at least three adjacent surfaces of the cell group 10. At least a portion of any surface of the cell group 10 is covered by at least one of the first binding member 20, the second binding member 30, and the third binding member 40 overlaps with at least a portion of the first binding member 20. Preferably, the second binding member 30 and the third binding member 40 cover the outer surface of the first binding member 20. Furthermore, as... Figure 1 In the embodiment shown, there are two battery cells 11.

[0031] When using the electrode assembly of this application, since it includes a cell assembly 10, a first binding member 20, a second binding member 30, and a third binding member 40, and any one of the first binding member 20, the second binding member 30, and the third binding member 40 is attached to at least three adjacent surfaces of the cell assembly 10, and any surface of the cell assembly 10 is attached to at least one of the first binding member 20, the second binding member 30, and the third binding member 40, all surfaces of the cell assembly 10 can be bound by the first binding member 20, the second binding member 30, and the third binding member 40, thereby improving the consistency of the overall force on the cell, ensuring uniform force on the electrode sheet, and thus preventing wrinkles from forming on the electrode sheet. Simultaneously, since the second binding member 30 and the third binding member 40 respectively cover at least a portion of the first binding member 20, the stability of the attachment between each binding member and the cell assembly 10 can be effectively guaranteed. Therefore, the electrode assembly of this application effectively solves the problem in the prior art where cells are prone to wrinkling due to poor force consistency and uneven local force.

[0032] Furthermore, in this application, the first restraint member 20, the second restraint member 30, and the third restraint member 40 can be adhesive tape.

[0033] Meanwhile, in this application, since the battery cell assembly 10 is composed of multiple battery cells 11 arranged along the X-axis, each surface of the battery cell assembly 10 at both ends of the Y-axis and Z-axis directions actually contains the surfaces of multiple battery cells 11. However, for ease of description, the surface of the battery cell assembly 10 composed of the surfaces of multiple battery cells 11 is regarded as a single surface in this application. Furthermore, in this application, the two surfaces of the battery cell assembly 10 at both ends of the Z-axis direction are the top surface and the bottom surface, respectively, while the two surfaces of the battery cell assembly 10 at both ends of the X-axis direction are the large surfaces of the battery cells 11 (the surfaces with the largest area of ​​the battery cells 11), and the two surfaces of the battery cell assembly 10 at both ends of the Y-axis direction are the curved surfaces formed by the arcuate surfaces of multiple battery cells 11.

[0034] Specifically, the first binding member 20 is wound around the cell assembly 10, and the first binding member 20 is respectively attached to the surfaces of the cell assembly 10 at both ends in the Z-axis direction and the surfaces of the cell assembly 10 at both ends in the X-axis direction. At the same time, the first binding member 20 is attached to the cell assembly 10 around the Y-axis, and the projection of the first binding member 20 in the XZ plane is annular. That is to say, in this application, the first binding member 20 can be attached to the top surface, bottom surface and two large surfaces of the cell assembly 10 by wrapping and pasting, thereby achieving the effect of binding multiple cells 11, and at the same time preventing the multiple cells 11 from separating.

[0035] Optionally, there may be multiple first restraint members 20, which are spaced apart along the Y-axis. Further optionally, in this application, the number of battery cells 11 is two. Of course, in this application, the number of first restraint members 20, second restraint members 30, third restraint members 40, and battery cells 11 can be adaptively adjusted according to different design requirements.

[0036] Optionally, at least one first binding member 20 is attached between the positive electrode tab 111 and the negative electrode tab 112, on the side of the positive electrode tab 111 away from the negative electrode tab 112, and on the side of the negative electrode tab 112 away from the positive electrode tab 111. In one specific embodiment of this application, there are three first binding members 20, and one first binding member 20 is attached between the positive electrode tab 111 and the negative electrode tab 112, on the side of the positive electrode tab 111 away from the negative electrode tab 112, and on the side of the negative electrode tab 112 away from the positive electrode tab 111. This arrangement can further improve the uniformity of force on the cell assembly 10, and also increase the binding force of the first binding members 20 on the cell assembly 10.

[0037] In the above embodiments, although a first binding member 20 is attached between the positive electrode tab 111 and the negative electrode tab 112, on the side of the positive electrode tab 111 away from the negative electrode tab 112, and on the side of the negative electrode tab 112 away from the positive electrode tab 111, it is still necessary to ensure that the first binding member 20 does not contact the positive electrode tab 111 and the negative electrode tab 112. Therefore, optionally, along a third direction, the first binding member 20 has a first distance from the central axis of the positive electrode tab 111, the positive electrode tab 111 has multiple positive electrode tabs, half the width of the connection between the positive electrode tab and the battery cell 11 is the first width, and the difference between the first distance and the first width is not less than 5mm; optionally, along a third direction, the first binding member 20 has a second distance from the central axis of the negative electrode tab 112, the negative electrode tab 112 has multiple negative electrode tabs, half the width of the connection between the negative electrode tab and the battery cell 11 is the second width, and the difference between the second distance and the second width is not less than 5mm. The purpose of this design is that when the tabs are folded into tabs, due to process errors, it is difficult for the tabs to be perfectly aligned. Therefore, by making the distance between the first restraint member 20 and the central axis of the tab at least 5mm larger than half the width of the tab, it is possible to avoid the first restraint member 20 from sticking to the tab due to process errors, thereby affecting the subsequent bending and other processes of the tab.

[0038] Preferably, the width of the first restraint member 20 that is attached between the positive electrode tab 111 and the negative electrode tab 112 is greater than the width of the other first restraint members 20.

[0039] Specifically, the second restraining member 30 is wound around the cell assembly 10, and the second restraining member 30 is respectively attached to the surfaces of the cell assembly 10 at both ends in the X-axis direction and the surfaces of the cell assembly 10 at both ends in the Y-axis direction. Further optionally, the second restraining member 30 is attached to the cell assembly 10 around the Z-axis, and the projection of the second restraining member 30 in the XY plane is annular. That is to say, in this application, the second restraining member 30 can attach the curved surface and two large surfaces of the cell assembly 10 by wrapping and pasting, thereby ensuring that the multiple cells 11 do not shift in the Y-axis direction, and thus ensuring a more orderly arrangement of the multiple cells 11.

[0040] Optionally, in the Z-axis direction, the second restraint member 30 is positioned closer to the top surface of the battery cell assembly 10 than the bottom surface of the battery cell assembly 10. Of course, in this application, the wrapping and pasting position of the second restraint member 30 in the Z-axis direction can be adaptively adjusted according to actual design requirements.

[0041] Specifically, the third restraint member 40 is in contact with the surfaces at both ends of the battery cell assembly 10 in the X-axis direction and the bottom surface of the battery cell assembly 10 in the Z-axis direction. Furthermore, it should be noted that, regarding the positional relationship between the second restraint member 30 and the third restraint member 40, to ensure more uniform force distribution on the battery cell assembly 10, the second restraint member 30 and the third restraint member 40 are spaced apart in the Z-axis direction, or in other words, they do not contact each other in the Z-axis direction.

[0042] Optionally, the battery cell 11 has a straight section and a curved section. The curved section is disposed at both ends of the straight section along a third direction, and the projection of the third restraining member 40 is located within the projection of the straight section of the battery cell 11 along a second direction. Therefore, when the third restraining member 40 is disposed on the battery cell 11, it is necessary to ensure that the third restraining member 40 avoids the curved section of the battery cell 11 to prevent the third restraining member 40 from contacting the arc-shaped surface. Alternatively, the two ends of the third restraining member 40 in the Y-axis direction are spaced apart from the two ends of the battery cell assembly 10 in the Y-axis direction. Further optionally, the projection of the third restraining member 40 in the XZ plane is U-shaped. In this application, since the curved surface of the battery cell assembly 10 is composed of the arc-shaped surfaces of multiple battery cells 11, it is necessary to avoid the third restraining member 40 from contacting the arc-shaped surface of the battery cell 11 in order to prevent wrinkles from appearing during the pasting process.

[0043] Optionally, the portion of the third restraining member 40 that contacts the surfaces of the battery cell assembly 10 at both ends in the second direction has a dimension in the first direction of not less than 10 mm. The main purpose of limiting this dimension range is to ensure a more stable fit between the third restraining member 40 and the surfaces of the battery cell assembly 10 at both ends in the second direction, thereby guaranteeing the fit effect of the third restraining member 40. Of course, depending on actual usage requirements, the specific value of the dimension in the first direction of the portion of the third restraining member 40 that contacts the surfaces of the battery cell assembly 10 at both ends in the second direction can be adaptively adjusted.

[0044] Furthermore, in this application, the thickness of the second restraining member 30 and the thickness of the third restraining member 40 can both be greater than the thickness of the first restraining member 20, so as to more effectively resist the expansion of the battery cell 11. At the same time, in order to further ensure the uniformity of the force on the battery cell assembly 10, the projection of the first restraining member 20 on the YZ surface is perpendicular to the projection of the second restraining member 30 on the YZ surface and the projection of the third restraining member 40 on the YZ surface, respectively.

[0045] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:

[0046] 1. Effectively solves the problem of wrinkles easily generated in existing battery cells due to poor stress consistency and uneven local stress;

[0047] 2. Simple structure and stable performance.

[0048] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0049] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0050] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0051] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An electrode assembly, characterized in that, The battery assembly includes a battery cell group (10), which includes at least one battery cell (11). The battery cell (11) has a positive electrode tab (111) and a negative electrode tab (112) on its top surface in a first direction, and all the battery cells (11) are arranged along a second direction. The electrode assembly also includes electrodes respectively disposed on the battery cell group (10). First restraint element (20); Second restraint (30); The third restraint member (40) is attached to at least three adjacent surfaces of the battery cell assembly (10), any one of the first restraint member (20), the second restraint member (30), and the third restraint member (40) is covered by at least one of the first restraint member (20), the second restraint member (30), and the third restraint member (40), and the second restraint member (30) and the third restraint member (40) are respectively disposed overlapping at least a portion of the first restraint member (20).

2. The electrode assembly according to claim 1, characterized in that, The first restraint member (20) is wound around the battery cell assembly (10), and the first restraint member (20) is respectively attached to the surfaces of the battery cell assembly (10) at both ends in the first direction and the surfaces of the battery cell assembly (10) at both ends in the second direction; and / or The second restraint member (30) is wound around the battery cell assembly (10), and the second restraint member (30) is respectively attached to the surfaces of the battery cell assembly (10) at both ends in the second direction and the surfaces of the battery cell assembly (10) at both ends in the third direction; and / or The third restraint member (40) is respectively attached to the surfaces of the battery cell assembly (10) at both ends in the second direction and the bottom surface of the battery cell assembly (10) in the first direction.

3. The electrode assembly according to claim 2, characterized in that, There are multiple first restraint members (20), and the multiple first restraint members (20) are spaced apart along a third direction.

4. The electrode assembly according to claim 3, characterized in that, At least one of the first binding members (20) is attached between the positive electrode tab (111) and the negative electrode tab (112), on the side of the positive electrode tab (111) away from the negative electrode tab (112), and on the side of the negative electrode tab (112) away from the positive electrode tab (111).

5. The electrode assembly according to claim 2, characterized in that, Along the third direction, the first restraint member (20) and the central axis of the positive electrode tab (111) have a first distance, the positive electrode tab (111) has a plurality of positive electrode tabs, half the width of the connection between the positive electrode tab and the battery cell (11) is the first width, and the difference between the first distance and the first width is not less than 5 mm; and / or, along the third direction, the first restraint member (20) and the central axis of the negative electrode tab (112) have a second distance, the negative electrode tab (112) has a plurality of negative electrode tabs, half the width of the connection between the negative electrode tab and the battery cell (11) is the second width, and the difference between the second distance and the second width is not less than 5 mm.

6. The electrode assembly according to claim 2, characterized in that, In the first direction, the second restraint member (30) is disposed near the top surface of the battery cell assembly (10) relative to the bottom surface of the battery cell assembly (10).

7. The electrode assembly according to claim 2, characterized in that, The battery cell (11) has a straight section and a curved section. The curved section is disposed at both ends of the straight section along a third direction. Along the second direction, the projection of the third restraint member (40) is located within the projection of the straight section of the battery cell (11).

8. The electrode assembly according to claim 7, characterized in that, The portion of the third restraint member (40) that is in contact with the surfaces of the battery cell assembly (10) at both ends in the second direction has a dimension of not less than 10 mm in the first direction.

9. The electrode assembly according to any one of claims 1 to 8, characterized in that, The thickness of the second restraint member (30) and / or the thickness of the third restraint member (40) is greater than the thickness of the first restraint member (20).

10. A secondary battery, characterized in that, The electrode assembly includes any one of claims 1 to 9.

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