Single cell and battery pack

Abstract

The application discloses a single battery and a battery pack, and relates to the technical field of batteries.The single battery comprises a first winding core and a second winding core, the first winding core comprises a first pole piece assembly and a first diaphragm, the first pole piece assembly comprises a first positive pole piece and a first negative pole piece, the first diaphragm comprises a first isolation section located between the first positive pole piece and the first negative pole piece and a first tail section wound around the outer periphery of the first pole piece assembly, the second winding core is stacked along a third direction with the first winding core, the second winding core comprises a second pole piece assembly and a second diaphragm, the second pole piece assembly comprises a second positive pole piece and a second negative pole piece, the second diaphragm comprises a second isolation section located between the second positive pole piece and the second negative pole piece and a second tail section wound around the outer periphery of the second pole piece assembly, and the first tail section and the second tail section are connected.The single battery can enhance the binding force of the diaphragm on the two winding cores by connecting the diaphragm tail sections of the two winding cores.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a single cell battery and a battery pack. Background Technology

[0002] During the first charge of a lithium-ion battery, the entire core undergoes significant expansion and deformation due to factors such as lithium-ion migration and gas generation from interfacial side reactions, with the deformation concentrated in the corner areas. This process continuously stretches the separator and electrode structure, causing the negative electrode to slip due to lack of fixation. After the battery discharges, insufficient stress and limited separator binding force in the corner areas prevent the slipped electrode from fully returning to its original position, ultimately leading to an abnormally large gap between the positive and negative electrodes at the corners of the outer ring of the core. Excessive corner gaps lengthen the lithium-ion migration path, increase the impedance in the corner area, and cause problems such as corner purple spots and localized lithium plating during long-term cycling, severely impacting long-term cycle life and safety performance. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a single-cell battery that, by connecting the end sections of the separators of two winding cores, enhances the binding force of the separators on the two winding cores, suppresses electrode slippage in the corner area, and improves the cycle life and safety performance of the battery.

[0004] The present invention also proposes a battery pack having the above-mentioned single cell.

[0005] A single-cell battery according to a first aspect of the present invention has a third aspect, comprising: The first core includes a first electrode assembly and a first separator that are stacked and wound together. The first electrode assembly includes a first positive electrode and a first negative electrode. The first separator includes a first isolation section located between the first positive electrode and the first negative electrode, and a first closing section wound around the outer periphery of the first electrode assembly. The first isolation section and the first closing section are connected along the winding direction of the first core. The second core is stacked with the first core along a third direction. The second core includes a second electrode assembly and a second diaphragm stacked and wound together. The second electrode assembly includes a second positive electrode and a second negative electrode. The second diaphragm includes a second isolation section located between the second positive electrode and the second negative electrode, and a second tailing section wound around the outer periphery of the second electrode assembly. The second isolation section and the second tailing section are connected along the winding direction of the second core. The first and second ending segments are connected.

[0006] The single-cell battery according to embodiments of the present invention has at least the following beneficial effects: This application connects the first end segment of the first core to the second end segment of the second core, forming a unified confinement structure for the separator systems of the two cores. During charge-discharge cycles, when expansion deformation occurs in the corner area of ​​the core, the connected end segments work synergistically to exert a stronger confinement force on the electrodes in the first and second electrode assemblies, suppressing electrode slippage on the separator surface. After discharge, due to the enhanced confinement force of the overall separator, the slipped electrodes can be better reset, thus maintaining the gap between the positive and negative electrodes at the corner of the outer ring of the core within a reasonable range. This prevents abnormal elongation of the lithium-ion migration path, reduces the impedance in the corner area, and effectively prevents the formation of corner purple spots and localized lithium plating, significantly improving the cycle life and safety performance of the battery.

[0007] According to some embodiments of the present invention, a first electrode assembly and a second electrode assembly are spaced apart along a third direction to define a first gap, and a first terminal section and a second terminal section are connected to form a connecting portion, which is located in the first gap.

[0008] According to some embodiments of the present invention, the single cell further has a first direction perpendicular to a third direction; the first core has a first straight area, a first corner area, and a second corner area, the first corner area and the second corner area being located on both sides of the first straight area along the first direction; the first ending section includes a first sub-segment located in the first straight area and a second sub-segment located in the first corner area, the first sub-segment and the second sub-segment being connected; the second core has a second straight area, a third corner area, and a fourth corner area, the third corner area and the fourth corner area being located on both sides of the second straight area along the first direction; the second ending section includes a third sub-segment located in the second straight area and a fourth sub-segment located in the fourth corner area, the third sub-segment and the fourth sub-segment being connected; wherein, the first sub-segment and the third sub-segment are connected along the first direction, and the first corner area is disposed opposite to the third corner area along a third direction, and the second corner area is disposed opposite to the fourth corner area along a third direction.

[0009] According to some embodiments of the present invention, a first electrode assembly includes a first starting end and a first ending end sequentially disposed along the winding direction of a first core, and a second electrode assembly includes a second starting end and a second ending end sequentially disposed along the winding direction of a second core, wherein the first ending end and the second ending end satisfy one of the following conditions: 1. The first end is located in the first flat region and is located on the side away from the second electrode assembly along the third direction; the second end is located in the second flat region and is located on the side away from the first electrode assembly along the third direction. 2. The first end is located in the first flat region and is located on the side closer to the second electrode assembly along the third direction; the second end is located in the second flat region and is located on the side closer to the first electrode assembly along the third direction. III. The first end is located in the first corner area, and the second end is located in the fourth corner area; IV. The first end is located in the second corner area, and the second end is located in the third corner area.

[0010] According to some embodiments of the present invention, a first electrode assembly includes a first starting end and a first ending end sequentially disposed along the winding direction of a first core, and a second electrode assembly includes a second starting end and a second ending end sequentially disposed along the winding direction of a second core, wherein the first ending end and the second ending end satisfy one of the following conditions: 1. The first end is located in the first flat region and is on the side closer to the second electrode assembly along the third direction; the second end is located in the second flat region and is on the side away from the first electrode assembly along the third direction. 2. The first end is located in the first flat region and is on the side away from the second electrode assembly in the third direction, and the second end is located in the second flat region and is on the side closer to the first electrode assembly in the third direction. III. The first end is located in the first corner area, and the second end is located in the third corner area; IV. The first end is located in the second corner area, and the second end is located in the fourth corner area.

[0011] According to some embodiments of the present invention, the first and second tail sections are heat-fused or glued together.

[0012] According to some embodiments of the present invention, the single cell also has a first direction perpendicular to a third direction, and the first terminal segment and the second terminal segment are connected to the same end of the first electrode assembly and the second electrode assembly along the first direction.

[0013] According to some embodiments of the present invention, a first core has a first straight area, a first corner area, and a second corner area, the first corner area and the second corner area being located on both sides of the first straight area along a first direction, and a first finishing section including a first sub-segment located in the first straight area and a second sub-segment located in the first corner area, the first sub-segment and the second sub-segment being connected; a second core has a second straight area, a third corner area, and a fourth corner area, the third corner area and the fourth corner area being located on both sides of the second straight area along a first direction, and a second finishing section including a third sub-segment located in the second straight area and a fourth sub-segment located in the third corner area, the third sub-segment and the fourth sub-segment being connected; wherein, the second sub-segment and the fourth sub-segment are connected along a third direction, and the first corner area is disposed opposite to the third corner area along a third direction, and the second corner area is disposed opposite to the fourth corner area along a third direction.

[0014] According to some embodiments of the present invention, a first core has a first straight area, a first corner area, and a second corner area, the first corner area and the second corner area being located on both sides of the first straight area along a first direction, and a first finishing section including a first sub-segment located in the first straight area and a second sub-segment located in the second corner area, the first sub-segment and the second sub-segment being connected; a second core has a second straight area, a third corner area, and a fourth corner area, the third corner area and the fourth corner area being located on both sides of the second straight area along a first direction, and a second finishing section including a third sub-segment located in the second straight area and a fourth sub-segment located in the fourth corner area, the third sub-segment and the fourth sub-segment being connected; wherein, the second sub-segment and the fourth sub-segment are connected along a third direction, and the first corner area is disposed opposite to the third corner area along a third direction, and the second corner area is disposed opposite to the fourth corner area along a third direction.

[0015] The battery pack according to a second aspect of the present invention includes the single battery cells mentioned in any of the above embodiments.

[0016] Additional aspects and advantages of the 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

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the dual-core structure of a single cell according to an embodiment of the present invention (the end section is connected between the first core and the second core). Figure 2 for Figure 1 Exploded view of the double-core structure; Figure 3 This is a schematic diagram of a dual-core structure of a single cell according to another embodiment of the present invention (the end section is connected between the first core and the second core, and the first core and the second core are arranged in the same orientation). Figure 4 This is a schematic diagram of the dual-core structure of a single cell according to an embodiment of the present invention (the end section is connected to the same end of the first core and the second core). Figure 5 for Figure 4 An exploded view of the double-core structure.

[0018] Figure label: First direction X; Second direction Y; Third direction Z; First core 100; First straight region 101; First corner region 102; Second corner region 103; First electrode assembly 110; First starting end 1101; First ending end 1102; First positive electrode 111; First negative electrode 112; First separator 120; First isolation section 121; First closing section 122; First sub-segment 1221; Second sub-segment 1222; Second core 200; Second straight region 201; Third corner region 202; Fourth corner region 203; Second electrode assembly 210; Second starting end 2101; Second ending end 2102; Second positive electrode 211; Second negative electrode 212; Second separator 220; Second isolation section 221; Second closing section 222; Third sub-segment 2221; Fourth sub-segment 2222; First gap 300; connecting part 310. Detailed Implementation

[0019] Embodiments of the present invention 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 the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] In the description of this invention, "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.

[0022] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0023] In the description of this invention, 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 the invention. 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.

[0024] During the first charge of a lithium-ion battery, the entire core undergoes significant expansion and deformation due to factors such as lithium-ion migration and gas generation from interfacial side reactions, with the deformation concentrated in the corner areas. This process continuously stretches the separator and electrode structure, causing the negative electrode to slip due to lack of fixation. After the battery discharges, insufficient stress and limited separator binding force in the corner areas prevent the slipped electrode from fully returning to its original position, ultimately leading to an abnormally large gap between the positive and negative electrodes at the corners of the outer ring of the core. Excessive corner gaps lengthen the lithium-ion migration path, increase the impedance in the corner area, and cause problems such as corner purple spots and localized lithium plating during long-term cycling, severely impacting long-term cycle life and safety performance.

[0025] To address the aforementioned issues, this application proposes a single-cell battery. For ease of description, this single-cell battery is defined as having a first direction X, a second direction Y, and a third direction Z that are mutually perpendicular. It should be noted that the single-cell battery in this embodiment has a dual-core structure; that is, the single-cell battery contains two independent core structures. For ease of description, these two core structures are respectively named the first core 100 and the second core 200. The second core 200 and the first core 100 are stacked together along the third direction Z.

[0026] like Figure 1 As shown, the first core 100 includes a first electrode assembly 110 and a first separator 120 stacked and wound together. The first electrode assembly 110 includes a first positive electrode 111 and a first negative electrode 112. In the unfolded state, the first negative electrode 112, the first separator 120, the first positive electrode 111, and the first separator 120 are stacked together. In the core structure formed after winding, the first negative electrode 112, the first separator 120, the first positive electrode 111, and the first separator 120 are stacked sequentially in a radial direction from the inside to the outside.

[0027] The first diaphragm 120 includes a first isolation section 121 located between the first positive electrode 111 and the first negative electrode 112. The first isolation section 121 is used to isolate the positive and negative electrodes to prevent short circuits. The first diaphragm 120 also includes a first termination section 122 wound around the outer periphery of the first electrode assembly 110. The first termination section 122 is used to fix the outermost ring of the first electrode assembly 110, prevent the electrode from radially displacing or loosening during charging and discharging, and can also serve to insulate it from the housing, thereby preventing short circuits caused by contact between the core and the housing. The first isolation section 121 and the first termination section 122 are connected along the winding direction of the first core 100, together forming a complete diaphragm structure.

[0028] Similarly, the second core 200 includes a second electrode assembly 210 and a second diaphragm 220 stacked and wound together. The second electrode assembly 210 includes a second positive electrode 211 and a second negative electrode 212. The second diaphragm 220 includes a second isolation section 221 located between the second positive electrode 211 and the second negative electrode 212, and a second termination section 222 wound around the outer periphery of the second electrode assembly 210. The second isolation section 221 and the second termination section 222 are connected along the winding direction of the second core 200. During the winding process, the second isolation section 221 isolates the second positive electrode 211 and the second negative electrode 212 from each other. The second termination section 222 is wound around the outermost periphery of the second electrode assembly 210, forming a circumferential covering of the second electrode assembly 210.

[0029] It should be noted that in the dual-core structure of this application, the first end section 122 of the first diaphragm 120 and the second end section 222 of the second diaphragm 220 are connected. It is understood that there can be multiple ways to connect the first end section 122 and the second end section 222. For example, the first end section 122 and the second end section 222 can be joined by heat fusion, that is, the ends of the two end sections are heated to a molten state and then pressed together, and after cooling, an integral fused structure is formed. In other examples, the first end section 122 and the second end section 222 can also be joined by adhesive bonding, that is, adhesive is applied to at least one of the two end sections, and then the two end sections are stacked, so that the two end sections are bonded and fixed after the adhesive cures. In other embodiments, the first end section 122 and the second end section 222 can also be connected by ultrasonic welding or mechanical fastening, as long as the fixation of the two end sections can be achieved.

[0030] Based on the above, this application connects the first termination section 122 and the second termination section 222, so that the diaphragm system of the first core 100 and the second core 200 forms an integral binding structure. During charge and discharge cycles, when the corner areas of the first core 100 and the second core 200 expand and deform, the first termination section 122 and the second termination section 222 stretch each other. Since the first isolation section 121 and the second isolation section 221 are wound and fixed inside their respective electrode assemblies, the first termination section 122 and the second termination section 222 will not slip or detach relative to each other, thereby maintaining a continuous fastening effect on the electrode assembly.

[0031] In addition, the first end section 122 and the second end section 222 can absorb part of the expansion stress through their own elastic deformation, buffering the volume change of the electrode assembly during the charging and discharging process. After the charging and discharging is completed, the elastic restoring force causes the electrode assembly to return to its initial shape, so that the electrode gap generated during the expansion process can be quickly restored, ensuring the relative position between the positive and negative electrodes is stable. This keeps the gap between the positive and negative electrodes at the corner of the first core 100 and the second core 200 within a reasonable range, avoiding abnormal elongation of the lithium ion migration path, reducing the impedance in the corner area, and thus effectively preventing the generation of corner purple spots and local lithium plating, improving the cycle life and safety performance of the single battery.

[0032] In some embodiments, such as Figure 1 and Figure 2 As shown, the first electrode assembly 110 and the second electrode assembly 210 are spaced apart along a third direction Z, thereby defining a first gap 300 between the first core 100 and the second core 200. The first termination section 122 and the second termination section 222 are connected to form a connecting portion 310, which is located within the first gap 300. It can be understood that, in the case of… Figure 1 and Figure 2 In the embodiment shown, the first tail section 122 and the second tail section 222 extend in opposite directions and connect to form a connecting part 310 after extending in opposite directions. This structural design of extending in opposite directions and connecting makes the expansion force on the first tail section 122 and the second tail section 222 act in opposite directions when the core expands. As a result, the first tail section 122 and the second tail section 222 have a mutual restraining effect.

[0033] In addition, since the connecting part 310 is located in the first gap 300, when the first core 100 and the second core 200 are stacked, the space of the first gap 300 will be compressed so that the connecting part 310 is clamped, thereby providing additional constraint force to further limit the displacement of the diaphragm end section when the core expands, and ensure that the diaphragm remains in a stable position during long-term cycling.

[0034] In some embodiments, such as Figure 1 and Figure 2As shown, the first core 100 has a first straight region 101, a first corner region 102, and a second corner region 103. The first corner region 102 and the second corner region 103 are located on both sides of the first straight region 101 along the first direction X. As shown, the first positive electrode 111 and the first negative electrode 112 in the first straight region 101 are both straight, while the first positive electrode 111 and the first negative electrode 112 in the first corner region 102 and the second corner region 103 are curved.

[0035] The first finishing section 122 includes a first sub-segment 1221 and a second sub-segment 1222, which are connected along the winding direction of the first core 100. As shown in the figure, the first sub-segment 1221 is located in the first straight section 101 and is located on the outermost side of the first straight section 101 along the third direction Z. The second sub-segment 1222 is located in the first corner section 102 and is located on the outermost side of the first corner section 102 along the first direction X.

[0036] Similarly, the second core 200 has a second straight section 201, a third corner section 202, and a fourth corner section 203, with the third corner section 202 and the fourth corner section 203 located on both sides of the second straight section 201 along the first direction X. The second finishing section 222 includes a third sub-segment 2221 located in the second straight section 201 and a fourth sub-segment 2222 located in the fourth corner section 203, with the third sub-segment 2221 and the fourth sub-segment 2222 connected.

[0037] Specifically, the first sub-segment 1221 and the third sub-segment 2221 are connected along the first direction X, thus connecting the straight-section finishing sections of the two cores into one unit along the first direction X. Furthermore, the first corner area 102 is positioned opposite to the third corner area 202 along the third direction Z, and the second corner area 103 is positioned opposite to the fourth corner area 203 along the third direction Z; that is, the extending directions of the finishing sections of the two cores are opposite. Figure 2 In the illustrated embodiment, the second sub-segment 1222 is located in the second corner area 103 on the right side. Therefore, the first sub-segment 1221 extends from right to left as shown in the figure, and the left end of the first sub-segment 1221 is the end of the first closing segment 122. The fourth sub-segment 2222 is located in the fourth corner area 203 on the left side. Therefore, the third sub-segment 2221 extends from left to right as shown in the figure, and the right end of the third sub-segment 2221 is the end of the second closing segment 222.

[0038] The first segment 1221 and the third segment 2221 are connected to form an integral structure. When the two cores expand, the expansion forces on the first segment 1221 and the third segment 2221 are in opposite directions, thus offsetting some of the expansion stress and effectively suppressing the overall dimensional change of the core along the first direction X, thereby improving the stability of the double core structure.

[0039] Furthermore, the structures of the first core 100 and the second core 200 can be the same or different, and their placement can be the same or different. For example, in... Figure 1 In the illustrated embodiment, the first core 100 and the second core 200 have the same structure but different orientations. The second core 200 is rotated 180° relative to the first core 100 along its own winding center axis before being stacked with the first core 100. Figure 3 In the embodiment shown, the first core 100 and the second core 200 are placed in the same orientation, but their structures differ. Specifically, the first electrode assembly 110 and the second electrode assembly 210 are structurally identical and placed in the same orientation, but the number of winding layers of the first diaphragm 120 and the second diaphragm 220 differs.

[0040] The first electrode assembly 110 includes a first starting end 1101 and a first ending end 1102 sequentially arranged along the winding direction of the first core 100, and the second electrode assembly 210 includes a second starting end 2101 and a second ending end 2102 sequentially arranged along the winding direction of the second core 200. (Reference) Figure 1 The positional relationship between the first end 1102 and the second end 2102 in the double-core structure shown in the flipped arrangement can be any of the following: Scenario 1: The first end 1102 is located in the first flat region 101 and is located on the side away from the second electrode assembly 210 along the third direction Z; the second end 2102 is located in the second flat region 201 and is located on the side away from the first electrode assembly 110 along the third direction Z.

[0041] Scenario 2: The first end 1102 is located in the first flat region 101 and is located on the side closer to the second electrode assembly 210 along the third direction Z; the second end 2102 is located in the second flat region 201 and is located on the side closer to the first electrode assembly 110 along the third direction Z.

[0042] Scenario 3: Reference Figure 1 and Figure 2 As shown, the first end 1102 is located in the first corner area 102, and the second end 2102 is located in the fourth corner area 203.

[0043] Scenario 4: The first end 1102 is located in the second corner area 103, and the second end 2102 is located in the third corner area 202.

[0044] Based on the different end positions mentioned above, this application can flexibly arrange the structure and orientation of the first electrode assembly 110 and the second electrode assembly 210 according to the electrode lead-out position, winding process, etc.

[0045] Different from Figure 1The illustrated embodiment, in Figure 3 In the illustrated embodiment, the first core 100 and the second core 200 of the dual-core structure are positioned in the same orientation. Therefore, the positions of the first end 1102 and the second end 2102 can also be arranged in any of the following ways: Scenario 1: The first end 1102 is located in the first flat region 101 and is on the side closer to the second electrode assembly 210 along the third direction Z; the second end 2102 is located in the second flat region 201 and is on the side away from the first electrode assembly 110 along the third direction Z.

[0046] Scenario 2: The first end 1102 is located in the first flat region 101 and is on the side away from the second electrode assembly 210 along the third direction Z; the second end 2102 is located in the second flat region 201 and is on the side closer to the first electrode assembly 110 along the third direction Z.

[0047] Scenario 3: The first end 1102 is located in the first corner area 102, and the second end 2102 is located in the third corner area 202.

[0048] Scenario 4: The first end 1102 is located in the second corner area 103, and the second end 2102 is located in the fourth corner area 203.

[0049] Understandably, in Figure 1 In the illustrated embodiment, the first core 100 and the second core 200 have identical structures, allowing them to share the same tooling and process parameters during production. This helps reduce manufacturing costs, and the separator thickness is relatively uniform, occupying less internal space, which is beneficial for improving the battery's energy density. Figure 3 In the embodiment shown, the first core 100 and the second core 200 are positioned in the same way, so that the second core 200 does not need to be flipped during the assembly process, which simplifies the assembly process and helps to improve production efficiency.

[0050] In some embodiments, the first termination segment 122 and the second termination segment 222 are joined by heat fusion. Specifically, the ends of the first termination segment 122 and the second termination segment 222 are heated to a molten state, and then the two molten ends are pressed together under pressure. After cooling, a fused integral connection structure is formed. Heat fusion is suitable for scenarios where the first diaphragm 120 and the second diaphragm 220 are made of the same material (such as polyethylene, polypropylene, etc.). After connection, the interface between the two termination segments disappears, forming a continuous integral diaphragm structure with high connection strength and without introducing additional dissimilar materials, ensuring the purity of the diaphragm system.

[0051] In other embodiments, the first termination segment 122 and the second termination segment 222 are connected by adhesive. Specifically, adhesive is applied between the ends of the first termination segment 122 and the second termination segment 222, and the two termination segments are bonded and fixed together after the adhesive cures. Adhesive connection is simple to operate, has stronger compatibility with diaphragm materials, and is suitable for connecting diaphragms of different materials.

[0052] Unlike the embodiment where the connecting portion 310 is located in the first gap 300, the connecting position of the diaphragm termination section can also be located at the same end of the first electrode assembly 110 and the second electrode assembly 210 along the first direction X. Specifically, refer to... Figure 4 and Figure 5 As shown, the first termination segment 122 and the second termination segment 222 are connected to the same end of the first electrode assembly 110 and the second electrode assembly 210 along the first direction X. It can be understood that the termination segments of the two cores are connected at the same end along the first direction X. At this position, there is no obstruction from the main structure of the core, and the space is relatively open, which facilitates the connection operation of the first termination segment 122 and the second termination segment 222.

[0053] For example, such as Figure 4 As shown, the first terminal segment 122 and the second terminal segment 222 can be connected to the right end of the first electrode assembly 110 and the second electrode assembly 210 in the figure, that is, the first sub-segment 1221 and the third sub-segment 2221 are connected at the positive end of the first direction X. In other examples (not shown in the figure), the first terminal segment 122 and the second terminal segment 222 can also be connected to the left end of the first electrode assembly 110 and the second electrode assembly 210 in the figure, that is, the first sub-segment 1221 and the third sub-segment 2221 are connected at the negative end of the first direction X.

[0054] In some embodiments (reference) Figure 4 and Figure 5 As shown, the first core 100 has a first straight section 101, a first corner section 102, and a second corner section 103, with the first corner section 102 and the second corner section 103 located on both sides of the first straight section 101 along a first direction X. The first finishing section 122 includes a first sub-segment 1221 located in the first straight section 101 and a second sub-segment 1222 located in the first corner section 102, with the first sub-segment 1221 and the second sub-segment 1222 connected. The second core 200 has a second straight section 201, a third corner section 202, and a fourth corner section 203, with the third corner section 202 and the fourth corner section 203 located on both sides of the second straight section 201 along a first direction X. The second finishing section 222 includes a third sub-segment 2221 located in the second straight section 201 and a fourth sub-segment 2222 located in the third corner section 202, with the third sub-segment 2221 and the fourth sub-segment 2222 connected.

[0055] The second sub-segment 1222 and the fourth sub-segment 2222 are connected along the third direction Z. Furthermore, the first corner area 102 is positioned opposite to the third corner area 202 along the third direction Z, and the second corner area 103 is positioned opposite to the fourth corner area 203 along the third direction Z. That is, the second sub-segment 1222 and the fourth sub-segment 2222 are positioned opposite to each other along the third direction Z.

[0056] In other embodiments, the first core 100 has a first straight section 101, a first corner section 102, and a second corner section 103, with the first corner section 102 and the second corner section 103 located on opposite sides of the first straight section 101 along a first direction X. The first finishing section 122 includes a first sub-segment 1221 located in the first straight section 101 and a second sub-segment 1222 located in the second corner section 103, the first sub-segment 1221 and the second sub-segment 1222 being connected. The second core 200 has a second straight section 201, a third corner section 202, and a fourth corner section 203, with the third corner section 202 and the fourth corner section 203 located on opposite sides of the second straight section 201 along a first direction X. The second finishing section 222 includes a third sub-segment 2221 located in the second straight section 201 and a fourth sub-segment 2222 located in the fourth corner section 203, the third sub-segment 2221 and the fourth sub-segment 2222 being connected.

[0057] The second sub-segment 1222 and the fourth sub-segment 2222 are connected along the third direction Z, and the first corner area 102 is positioned opposite to the third corner area 202 along the third direction Z, and the second corner area 103 is positioned opposite to the fourth corner area 203 along the third direction Z.

[0058] It is understood that the difference between this embodiment and the previous embodiment is that the second sub-segment 1222 is located in the second corner area 103, and the fourth sub-segment 2222 is located in the fourth corner area 203, so that the finishing segments of the other set of diagonal corner areas of the two cores are connected along the third direction Z.

[0059] Based on the above, this application directly connects the tail sections of the two winding cores along the third direction Z in the corner region, so that the connection directly acts on the corner region where expansion deformation is most severe, resulting in a more direct suppression effect on electrode slippage. Whether the arrangement of the second sub-segment 1222 located in the first corner region 102 and the fourth sub-segment 2222 located in the third corner region 202, or the arrangement of the second sub-segment 1222 located in the second corner region 103 and the fourth sub-segment 2222 located in the fourth corner region 203, can be flexibly selected according to the electrode tab position, winding direction, and process layout, to suppress corner electrode slippage while optimizing the internal structural layout and manufacturing process of the single cell. Additionally, refer to... Figure 4As shown, since the connection position formed by the second sub-segment 1222 and the fourth sub-segment 2222 is located at the junction of the corner area of ​​the first core 100 and the second core 200, an approximately triangular recessed space is formed at the ends of the first core 100 and the second core 200 along the first direction X. This recessed space is conducive to realizing the connection operation of the second sub-segment 1222 and the fourth sub-segment 2222.

[0060] The second aspect of this application proposes a battery pack, which includes a housing and the individual batteries mentioned in any of the preceding embodiments. It should be noted that the individual batteries can be integrated into modules before being installed in the housing, or they can be directly installed in the housing; the specific integration method can be flexibly selected according to the actual application scenario. The housing is used to house and protect the individual batteries. Multiple individual batteries can be arranged within the housing, and these batteries can be arranged along a first direction X, a second direction Y, or a third direction Z, and connected in series and / or parallel to form a battery module or battery pack. Since the battery pack of this application uses the individual batteries from the aforementioned embodiments, the connection of the two winding end sections enhances the binding force of the separator on the electrode sheets, suppressing electrode slippage and abnormal gap increase in the corner area, thereby improving the cycle life and safety performance of the individual batteries. Therefore, the overall cycle life, reliability, and safety of the battery pack are significantly improved.

[0061] It is understood that since the battery pack of this application includes all the technical solutions in the previous embodiment, it should have the beneficial effects corresponding to that embodiment, and will not be repeated here.

[0062] 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, and various changes can be made within the scope of knowledge possessed by those skilled in the art 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 single-cell battery having a third orientation (Z), characterized in that, include: A first core (100) includes a first electrode assembly (110) and a first diaphragm (120) stacked and wound together. The first electrode assembly (110) includes a first positive electrode (111) and a first negative electrode (112). The first diaphragm (120) includes a first isolation section (121) located between the first positive electrode (111) and the first negative electrode (112), and a first closing section (122) wound around the outer periphery of the first electrode assembly (110). The first isolation section (121) and the first closing section (122) are connected along the winding direction of the first core (100). The second core (200) is stacked with the first core (100) along the third direction (Z). The second core (200) includes a second electrode assembly (210) and a second diaphragm (220) stacked and wound together. The second electrode assembly (210) includes a second positive electrode (211) and a second negative electrode (212). The second diaphragm (220) includes a second isolation section (221) located between the second positive electrode (211) and the second negative electrode (212), and a second tail section (222) wound around the outer periphery of the second electrode assembly (210). The second isolation section (221) and the second tail section (222) are connected along the winding direction of the second core (200). The first closing segment (122) and the second closing segment (222) are connected.

2. The single-cell battery according to claim 1, characterized in that, The first electrode assembly (110) and the second electrode assembly (210) are spaced apart along the third direction (Z) to define a first gap (300), and the first terminal segment (122) and the second terminal segment (222) are connected to form a connecting portion (310), which is located in the first gap (300).

3. The single-cell battery according to claim 2, characterized in that, The single cell also includes a first direction (X) perpendicular to the third direction (Z). The first core (100) has a first straight area (101), a first corner area (102), and a second corner area (103). The first corner area (102) and the second corner area (103) are respectively located on both sides of the first straight area (101) along the first direction (X). The first tail section (122) includes a first sub-segment (1221) located in the first straight area (101) and a second sub-segment (1222) located in the first corner area (102). The first sub-segment (1221) and the second sub-segment (1222) are connected. The second core (200) has a second straight section (201), a third corner section (202) and a fourth corner section (203), the third corner section (202) and the fourth corner section (203) are respectively located on both sides of the second straight section (201) along the first direction (X), and the second tail section (222) includes a third sub-segment (2221) located in the second straight section (201) and a fourth sub-segment (2222) located in the fourth corner section (203), the third sub-segment (2221) and the fourth sub-segment (2222) are connected; The first sub-segment (1221) and the third sub-segment (2221) are connected along the first direction (X), and the first corner area (102) is disposed opposite to the third corner area (202) along the third direction (Z), and the second corner area (103) is disposed opposite to the fourth corner area (203) along the third direction (Z).

4. The single-cell battery according to claim 3, characterized in that, The first electrode assembly (110) includes a first starting end (1101) and a first ending end (1102) arranged sequentially along the winding direction of the first core (100), and the second electrode assembly (210) includes a second starting end (2101) and a second ending end (2102) arranged sequentially along the winding direction of the second core (200). The first ending end (1102) and the second ending end (2102) satisfy one of the following conditions:

1. The first end (1102) is located in the first flat region (101) and is located on the side away from the second electrode assembly (210) along the third direction (Z), and the second end (2102) is located in the second flat region (201) and is located on the side away from the first electrode assembly (110) along the third direction (Z); 2. The first end (1102) is located in the first flat area (101) and is located on the side of the third direction (Z) close to the second electrode assembly (210), and the second end (2102) is located in the second flat area (201) and is located on the side of the third direction (Z) close to the first electrode assembly (110); Third, the first end (1102) is located in the first corner area (102), and the second end (2102) is located in the fourth corner area (203); Fourth, the first end (1102) is located in the second corner area (103), and the second end (2102) is located in the third corner area (202).

5. The single-cell battery according to claim 3, characterized in that, The first electrode assembly (110) includes a first starting end (1101) and a first ending end (1102) arranged sequentially along the winding direction of the first core (100), and the second electrode assembly (210) includes a second starting end (2101) and a second ending end (2102) arranged sequentially along the winding direction of the second core (200). The first ending end (1102) and the second ending end (2102) satisfy one of the following conditions:

1. The first end (1102) is located in the first flat region (101) and is on the side closer to the second electrode assembly (210) along the third direction (Z), and the second end (2102) is located in the second flat region (201) and is on the side away from the first electrode assembly (110) along the third direction (Z); 2. The first end (1102) is located in the first flat region (101) and is on the side away from the second electrode assembly (210) along the third direction (Z), and the second end (2102) is located in the second flat region (201) and is on the side close to the first electrode assembly (110) along the third direction (Z); Third, the first end (1102) is located in the first corner area (102), and the second end (2102) is located in the third corner area (202); Fourth, the first end (1102) is located in the second corner area (103), and the second end (2102) is located in the fourth corner area (203).

6. The single-cell battery according to claim 1, characterized in that, The first tail section (122) and the second tail section (222) are heat-fused or glued together.

7. The single-cell battery according to claim 1, characterized in that, The single cell also has a first direction (X) perpendicular to the third direction (Z), and the first terminal segment (122) and the second terminal segment (222) are connected to the same end of the first electrode assembly (110) and the second electrode assembly (210) along the first direction (X).

8. The single-cell battery according to claim 7, characterized in that, The first core (100) has a first straight area (101), a first corner area (102) and a second corner area (103). The first corner area (102) and the second corner area (103) are located on both sides of the first straight area (101) along the first direction (X). The first tail section (122) includes a first sub-segment (1221) located in the first straight area (101) and a second sub-segment (1222) located in the first corner area (102). The first sub-segment (1221) and the second sub-segment (1222) are connected. The second core (200) has a second straight section (201), a third corner section (202) and a fourth corner section (203), the third corner section (202) and the fourth corner section (203) being located on both sides of the second straight section (201) along the first direction (X), and the second tail section (222) including a third sub-segment (2221) located in the second straight section (201) and a fourth sub-segment (2222) located in the third corner section (202), the third sub-segment (2221) and the fourth sub-segment (2222) being connected; The second sub-segment (1222) and the fourth sub-segment (2222) are connected along the third direction (Z), and the first corner area (102) is disposed opposite to the third corner area (202) along the third direction (Z), and the second corner area (103) is disposed opposite to the fourth corner area (203) along the third direction (Z).

9. The single-cell battery according to claim 7, characterized in that, The first core (100) has a first straight area (101), a first corner area (102) and a second corner area (103). The first corner area (102) and the second corner area (103) are located on both sides of the first straight area (101) along the first direction (X). The first tail section (122) includes a first sub-segment (1221) located in the first straight area (101) and a second sub-segment (1222) located in the second corner area (103). The first sub-segment (1221) and the second sub-segment (1222) are connected. The second core (200) has a second straight section (201), a third corner section (202) and a fourth corner section (203), the third corner section (202) and the fourth corner section (203) are respectively located on both sides of the second straight section (201) along the first direction (X), and the second tail section (222) includes a third sub-segment (2221) located in the second straight section (201) and a fourth sub-segment (2222) located in the fourth corner section (203), the third sub-segment (2221) and the fourth sub-segment (2222) are connected; The second sub-segment (1222) and the fourth sub-segment (2222) are connected along the third direction (Z), and the first corner area (102) is disposed opposite to the third corner area (202) along the third direction (Z), and the second corner area (103) is disposed opposite to the fourth corner area (203) along the third direction (Z).

10. A battery pack, characterized in that, The battery pack includes the individual cells as described in any one of claims 1 to 9.

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