Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery, and relates to the technical field of new energy. The battery cell comprises a pole piece assembly and a diaphragm, the pole piece assembly comprises a positive pole piece and a negative pole piece, the diaphragm is arranged between the positive pole piece and the negative pole piece, the battery cell has a first direction, and the diaphragm extends out relative to the pole piece assembly at the two ends of the battery cell along the first direction. Setting the diaphragm of the extending part as a first extending part and a second extending part respectively; wherein the first extension part and the second extension part are respectively provided with a connecting area, and the diaphragms of the adjacent layers are directly connected through the connecting areas. The battery cell with the structure replaces gummed paper, so that the size of the battery cell in the thickness direction is further reduced, and the energy density of the battery can be further improved.

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. Depending on the manufacturing process and cell structure, cells can be divided into wound cells and stacked cells. After the electrodes are wound or stacked to form the cell, adhesive tape is often used to wrap around the outer periphery of the cell for fixation to prevent the electrodes from loosening or shifting.

[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 can reduce the size of the cell along the thickness direction, thereby further improving the energy density of the battery.

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

[0006] According to a first aspect of the present invention, a battery cell includes an electrode assembly and a separator. The electrode assembly includes a positive electrode and a negative electrode. The separator is disposed between the positive electrode and the negative electrode. The battery cell has a first direction. At both ends of the battery cell along the first direction, the separator extends out of the electrode assembly. The extended portions of the separator are defined as a first extension and a second extension, respectively.

[0007] Both the first extension and the second extension are provided with a connection area, and the diaphragms of adjacent layers are directly connected through the connection area.

[0008] The battery cell according to the embodiments of this utility model has at least the following beneficial effects:

[0009] The entire separator is constrained at both ends by connection areas along the first direction. When the separator is heated, these connection areas stretch the separator, limiting its shrinkage and reducing the risk of short circuits in the cell. This design optimizes the overall cell structure, ensures battery stability at high temperatures, and extends its lifespan. Furthermore, this design replaces the use of adhesive tape, further reducing the cell's thickness and thus increasing the battery's energy density.

[0010] According to some embodiments of the present invention, if the battery cell is a wound battery cell, the side of the electrode assembly with the tab is designated as the first side, and the side opposite to the first side is designated as the second side.

[0011] Wherein, the first direction is provided along the direction from the first side to the second side, the first extension extends out of the first side, and the second extension extends out of the second side.

[0012] According to some embodiments of the present invention, the separator further includes a main body portion located between the positive electrode and the negative electrode, and the second extension portion is bent relative to the main body portion so that the second extension portion fits against the end face of the second side of the electrode assembly.

[0013] According to some embodiments of the present invention, the electrode assembly includes a positive electrode tab and a negative electrode tab arranged at intervals. The positive electrode tab and the negative electrode tab divide the first extension into a first region, a second region, and a third region. The first region and the third region are located on opposite sides of the positive electrode tab and the negative electrode tab, respectively, and the second region is located between the positive electrode tab and the negative electrode tab.

[0014] The first region, the second region, and the third region are each provided with at least one of the connection areas.

[0015] According to some embodiments of the present invention, if the battery cell is a laminated battery cell, the end of the electrode assembly with the tab is designated as the first side, the end opposite to the first side is designated as the second side, and the other two sides are designated as the third side and the fourth side, respectively.

[0016] Wherein, the first direction is arranged along the direction from the first side to the second side, the first extension extends out of the first side, and the second extension extends out of the second side; or, the first direction is arranged along the direction from the third side to the fourth side, the first extension extends out of the third side, and the second extension extends out of the fourth side.

[0017] According to some embodiments of the present invention, if the first direction is arranged along the direction from the first side to the second side, the battery cell further includes a second direction arranged along the direction from the third side to the fourth side, and the separator further includes a third extension extending out of the third side and a fourth extension extending out of the fourth side;

[0018] Both the third extension and the fourth extension are provided with a connection area.

[0019] According to some embodiments of the present invention, the first extension and / or the second extension are provided with a plurality of connection areas, and the plurality of connection areas are spaced apart.

[0020] According to some embodiments of the present invention, the connection area includes a plurality of connection points, adjacent connection points are spaced apart, and at each connection point, the diaphragms of adjacent layers are bonded together.

[0021] And / or, the connection area includes a plurality of connection lines, adjacent connection lines are spaced apart, and at each connection line, the diaphragms of adjacent layers are bonded together;

[0022] And / or, the connection area includes multiple connection surfaces, with adjacent connection surfaces spaced apart, and at each connection surface, the diaphragms of adjacent layers are bonded together.

[0023] According to some embodiments of the present invention, the porosity of the connecting region of the diaphragm is 10% to 50% of that of the remaining region;

[0024] Alternatively, the bonding strength of the connecting area is 35 MPa to 55 MPa.

[0025] The battery according to a second aspect embodiment of the present invention includes the battery cell mentioned in any of the foregoing embodiments.

[0026] 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

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0028] Figure 1 This is a schematic diagram of the structure of the wound battery cell according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the stacked battery cell according to an embodiment of the present invention;

[0030] Figure 3 This is a side view of the wound battery cell according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram illustrating various embodiments of the connection area of ​​this utility model.

[0032] Figure label:

[0033] Electrode assembly 100; First side 101; Second side 102; Third side 103; Fourth side 104; Positive electrode tab 110; Negative electrode tab 120;

[0034] Diaphragm 200; First extension 210; First region 211; Second region 212; Third region 213; Second extension 220; Third extension 230; Fourth extension 240; Connecting area 250; Connecting point 251; Connecting line 252; Detailed Implementation

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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. Depending on the manufacturing process and cell structure, cells can be divided into wound cells and stacked cells. After the electrodes are wound or stacked to form the cell, adhesive tape is often used to wrap around the outer periphery of the cell for fixation to prevent the electrodes from loosening or shifting.

[0041] 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.

[0042] To address the aforementioned problems, a first aspect of this application provides a battery cell comprising an electrode assembly 100 and a separator 200. The electrode assembly 100 includes a positive electrode and a negative electrode, and the separator 200 is disposed between the positive and negative electrode to separate them and prevent direct contact that could lead to a short circuit. The battery cell has a first direction, and at least at both ends of the battery cell along the first direction, the separator 200 extends beyond the electrode assembly 100. The extended portions of the separator 200 are designated as a first extension 210 and a second extension 220. It should be noted that both the first extension 210 and the second extension 220 are provided with a connection region 250, and adjacent separator layers 200 are directly connected through the connection region 250.

[0043] It should be noted that at one end of the battery cell along the first direction, the various first extensions 210 overlap and are connected through the connection area 250. At the other end of the battery cell along the first direction, the various second extensions 220 overlap and are connected through the connection area 250. "Direct connection" means that without the use of other connecting parts, adjacent diaphragms 200 are directly bonded and fixed. Direct connection can be achieved through processes such as hot stamping, resistance welding, or ultrasonic welding. Taking hot stamping as an example, the hot stamping plate is set with a hot stamping pattern. After the various first extensions 210 are sequentially bonded and stacked, the hot stamping plate is aligned with the connection area 250. The diaphragms 200 are melted and bonded by heating the hot stamping plate, thereby firmly connecting the layers of diaphragms 200.

[0044] Thus, the two ends of the entire separator 200 along the first direction are respectively restricted by the connection areas 250 at both ends. When the separator 200 is heated, the connection areas 250 at both ends can pull the separator 200, restricting the separator 200 from shrinking, thereby reducing the risk of cell short circuit. This design optimizes the overall structure of the cell, ensures the stability of the battery in high temperature environment, and extends its service life.

[0045] Furthermore, this design replaces the adhesive tape, further reducing the cell's dimensions along the thickness direction, thereby enabling a further increase in the battery's energy density.

[0046] In some embodiments, when the battery cell is a wound battery cell, such as Figure 1 As shown, the end of the electrode assembly 100 with the tab is designated as the first side 101, and the end opposite to the first side 101 is designated as the second side 102. In the wound cell, the first direction is the direction of the first side 101 and the second side 102. Thus, the first extension 210 extends out of the first side 101 of the electrode assembly 100, and the second extension 220 extends out of the second side 102 of the electrode assembly 100. The diaphragm 200 of the second side 102 is securely connected through the connection area 250 on the extension.

[0047] Furthermore, for ease of description, the separator 200 is divided into a main body portion, a first extension portion 210, and a second extension portion 220, wherein the main body portion (not shown in the figure) refers to the portion of the separator 200 located between the positive electrode plate and the negative electrode plate. Based on the foregoing, as Figure 3 As shown, the second extension 220 refers to the portion of the diaphragm 200 that extends beyond the second side 102 of the electrode assembly 100. To reduce the dimensional impact of the second extension 220 on the cell's length, the second extension 220 is bent relative to the main body and conforms to the end face of the second side 102 of the electrode assembly 100. The bent second extension 220 not only reduces the overall size of the wound cell but also improves space utilization. To ensure the stability of the diaphragm 200 after bending, the second extension 220 can be properly fixed, for example, by using a slot or adhesive to connect it to the end face of the second side 102 of the electrode assembly 100.

[0048] On the other hand, due to the bending arrangement of the second extension 220, the movement of the separator 200 inside the cell can be further restricted based on the frictional force between adjacent separators 200, thereby improving the structural stability of the battery pack.

[0049] Furthermore, it can be understood that the tabs of the battery cell are typically divided into a positive tab 110 and a negative tab 120. The first extension 210 is provided with at least three connection areas 250, which are spaced apart from each other. The positive tab 110 extends from the positive electrode plate, and the negative tab 120 extends from the negative electrode plate and extends to the outside of the battery cell body to achieve concentrated current delivery. The positive tab 110 and the negative tab 120 are spaced apart from each other, thereby dividing the first extension 210 into three regions, as described below. Figure 1As shown, these regions are named First Region 211, Second Region 212, and Third Region 213, respectively. First Region 211 and Third Region 213 are located on opposite sides of the positive tab 110 and negative tab 120, respectively. Specifically, First Region 211 is located on the opposite side of the positive tab 110 away from the negative tab 120, and Third Region 213 is located on the opposite side of the negative tab 120 away from the positive tab 110. Second Region 212 is located between the positive tab 110 and the negative tab 120. Each of First Region 211, Second Region 212, and Third Region 213 has at least one connection area 250, allowing the separator 200 in each of these three regions to be confined and fixed by the connection area 250, ensuring the stability of the battery cell during charging and discharging.

[0050] In some embodiments, such as Figure 2 As shown, if the battery cell is a laminated cell, the end of the electrode assembly 100 with the tab is still designated as the first side 101, and the end opposite to the first side 101 is designated as the second side 102. The other two opposite sides of the electrode assembly 100, excluding the first side 101 and the second side 102, are designated as the third side 103 and the fourth side 104, respectively. For laminated cells, since the four edges of the separator 200 extend out of the electrode assembly 100, the first direction can be taken as the direction from the first side 101 to the second side 102 of the electrode assembly 100, with the first extension 210 extending out of the first side 101 and the second extension 220 extending out of the second side 102. Alternatively, the first direction can be taken as the direction perpendicular to the direction from the first side 101 to the second side 102 of the electrode assembly 100, that is, the direction from the third side 103 to the fourth side 104, with the first extension 210 extending out of the third side 103 and the second extension 220 extending out of the fourth side 104. Connection areas 250 are respectively provided on the first extension 210 and the second extension 220, thereby achieving fixation of the separator 200 on the corresponding side in any direction of the battery cell. This flexible design allows for better fixation and stability of the stacked battery cells in different directions. By selecting a suitable connection method, deformation of the battery cell under different stress conditions can be effectively prevented, thereby extending the overall battery life and improving its reliability in various applications.

[0051] Furthermore, if the first direction is set along the direction from the first side 101 to the second side 102, the battery cell also includes a second direction along the direction from the third side 103 to the fourth side 104. The separator 200 also includes a third extension 230 extending from the third side 103 and a fourth extension 240 extending from the fourth side 104. Both the third extension 230 and the fourth extension 240 are provided with connection areas 250. Thus, all four peripheral sides of the separator 200 are fixed and restricted by the connection areas 250, further improving the overall structural stability of the battery cell. The third extension 230 and the fourth extension 240 can also be referred to... Figure 3The second extension 220 is bent to fit against the side wall of the electrode assembly 100, thereby reducing the impact of the arrangement of the third extension 230 and the fourth extension 240 on the size of the battery in the second direction.

[0052] In some embodiments, a plurality of connection regions 250 are provided on the first extension 210 or the second extension 220, or both the first extension 210 and the second extension 220 are provided with a plurality of connection regions 250, with each connection region 250 spaced apart, so that while connecting adjacent layers of the diaphragm 200, the gaps between the connection regions 250 ensure that the electrolyte can smoothly wet the electrode assembly 100. Similarly, when the diaphragm 200 is also provided with a third extension 230 and a fourth extension 240, a plurality of connection regions 250 may also be provided on the third extension 230 and the fourth extension 240, with each connection region 250 also spaced apart.

[0053] In addition, to further enhance the impact of the connection area 250 on the electrolyte wetting effect, such as... Figure 4 As shown, the connecting area 250 can be configured with various patterns. Taking the hot stamping process to form the connecting area 250 as an example, the hot stamping plate can be configured with multiple spaced raised dot patterns. After the hot stamping plate transfers the pattern onto the connecting area 250, the connecting area 250 forms multiple spaced connecting points 251 (e.g., ...). Figure 4 As shown in Figure a), at each connection point 251, the diaphragms 200 of adjacent layers are bonded together. In the remaining portion of the connection area 250, gaps exist between the diaphragms 200 of adjacent layers to allow electrolyte to pass through. This design optimizes the electrolyte wetting path while ensuring the bonding strength between the diaphragms 200. Similarly, the pattern on the hot stamping plate can also be a spaced-out linear pattern, thus forming multiple connecting lines 252 in the connection area 250, with adjacent connecting lines 252 spaced apart. At each connecting line 252, the diaphragms 200 of adjacent layers are bonded together. The connecting lines 252 can be as follows: Figure 4 b、 Figure 4 c. Figure 4 The lines shown in d can be diagonal, vertical, or horizontal. Alternatively, the pattern on the hot stamping plate can be spaced-apart pattern blocks, thus forming multiple connecting surfaces (not shown in the figure) in the connecting area 250. Adjacent connecting surfaces are spaced apart, and at each connecting surface, the membranes of adjacent layers are bonded together. It is understood that at least two of the following can be formed simultaneously on the connecting area 250: connecting points 251, connecting lines 252, and connecting surfaces, achieving a balance between strength and electrolyte flowability through pattern design.

[0054] Furthermore, the porosity of the connecting region 250 on the diaphragm 200 is 10% to 50% of that of the remaining regions to ensure that the wetting effect of the electrolyte is not significantly affected. The bonding strength of the connecting region 250 is 35 MPa to 55 MPa to ensure the stability of the connection between adjacent diaphragm layers 200. The connecting region 250 can be as follows: Figure 4 The rectangle shown can also be an ellipse, triangle, etc. In addition, the distance between the connection area 250 and the edge of the electrode assembly 100 is 0.2mm to 1.2mm to avoid the diaphragm pressing the electrode due to the setting of the connection area 250.

[0055] The second aspect of this application also proposes a battery that includes the battery cell mentioned in any of the above embodiments. Therefore, the battery includes all the technical effects of any of the above embodiments, which will not be repeated here.

[0056] 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, The battery cell includes an electrode assembly and a separator. The electrode assembly includes a positive electrode and a negative electrode. The separator is disposed between the positive electrode and the negative electrode. The battery cell has a first direction. At both ends of the battery cell along the first direction, the separator extends out relative to the electrode assembly. The extended portions of the separator are defined as a first extension and a second extension, respectively. Both the first extension and the second extension are provided with a connection area, and the diaphragms of adjacent layers are directly connected through the connection area.

2. The battery cell according to claim 1, characterized in that, If the battery cell is a wound battery cell, the side of the electrode assembly with the tabs is designated as the first side, and the side opposite to the first side is designated as the second side. Wherein, the first direction is provided along the direction from the first side to the second side, the first extension extends out of the first side, and the second extension extends out of the second side.

3. The battery cell according to claim 2, characterized in that, The diaphragm also includes a main body portion located between the positive electrode and the negative electrode, wherein the second extension portion is bent relative to the main body portion so that the second extension portion conforms to the end face of the second side of the electrode assembly.

4. The battery cell according to claim 2, characterized in that, The electrode assembly includes a positive electrode tab and a negative electrode tab spaced apart. The positive electrode tab and the negative electrode tab divide the first extension into a first region, a second region, and a third region. The first region and the third region are located on opposite sides of the positive electrode tab and the negative electrode tab, respectively. The second region is located between the positive electrode tab and the negative electrode tab. The first region, the second region, and the third region are each provided with at least one of the connection areas.

5. The battery cell according to claim 1, characterized in that, If the cell is a laminated cell, the end of the electrode assembly with the tab is designated as the first side, the end opposite to the first side is designated as the second side, and the other two sides are designated as the third side and the fourth side, respectively. Wherein, the first direction is arranged along the direction from the first side to the second side, the first extension extends out of the first side, and the second extension extends out of the second side; or, the first direction is arranged along the direction from the third side to the fourth side, the first extension extends out of the third side, and the second extension extends out of the fourth side.

6. The battery cell according to claim 5, characterized in that, If the first direction is arranged along the direction from the first side to the second side, the cell further includes a second direction arranged along the direction from the third side to the fourth side, and the separator further includes a third extension extending out of the third side and a fourth extension extending out of the fourth side; Both the third extension and the fourth extension are provided with a connection area.

7. The battery cell according to claim 1, characterized in that, The first extension and / or the second extension are provided with a plurality of connection areas, which are spaced apart.

8. The battery cell according to claim 1, characterized in that, The connection area includes multiple connection points, with adjacent connection points spaced apart. At each connection point, the membranes of adjacent layers are bonded together. And / or, the connection area includes a plurality of connection lines, with adjacent connection lines spaced apart, and at each connection line, the diaphragms of adjacent layers are bonded together; And / or, the connection area includes multiple connection surfaces, with adjacent connection surfaces spaced apart, and at each connection surface, the diaphragms of adjacent layers are bonded together.

9. The battery cell according to claim 8, characterized in that, The porosity of the connecting region of the diaphragm is 10% to 50% of that of the remaining region; Alternatively, the bonding strength of the connecting area is 35 MPa to 55 MPa.

10. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 9.

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