Single cell and battery pack

Abstract

This utility model relates to the field of battery technology and discloses a single battery cell and a battery pack. The single battery cell includes an electrode assembly, which comprises a first electrode, a first separator, and a second electrode, all wound together. The first separator is located between the first and second electrode cells. The electrode assembly has an unfolding direction and a winding start side located in the unfolding direction. The first electrode has a first starting end located in the winding start side. The second electrode has a first extension segment, and the first separator has a second extension segment. In the unfolding direction, both the first and second extension segments extend relative to the first starting end toward the winding start side, and the first and second extension segments are fixedly connected. Fixing the first and second extension segments together ensures that the second electrode cell is tightly connected to the first separator, preventing gaps between the first and second electrode cells caused by deformation of the second electrode cell due to stress, reducing the risk of lithium plating in the single battery cell, and significantly improving battery safety.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a single battery cell and a battery pack. Background Technology

[0002] Lithium-ion power batteries have advantages such as small size, large capacity, high energy density, high charge / discharge rate, excellent low-temperature performance, long service life, and high safety. As the energy density requirements of electric vehicles and high-power electrical appliances increase, the size of traditional single-cell batteries is being forced to become increasingly larger.

[0003] A single cell includes a positive electrode, a negative electrode, and a separator. The negative electrode, separator, and positive electrode are wound along the winding direction. After the negative electrode is cut, it tends to deform inward due to stress deformation, which can easily cause gaps between the positive and negative electrodes, and lithium plating can easily occur during cycling. Utility Model Content

[0004] In view of this, the present invention provides a single cell battery and a battery pack to solve the problem that the negative electrode of a cylindrical cell is prone to inward deformation due to stress deformation after cutting, which can easily cause gaps between the positive and negative electrode plates.

[0005] In a first aspect, the present invention provides a single battery cell, comprising: an electrode assembly, the electrode assembly including a first electrode, a first separator, and a second electrode stacked and wound together, the first separator being located between the first electrode and the second electrode, the electrode assembly having an unfolding direction and a winding start side located in the unfolding direction; the first electrode having a first start end located in the winding start side, the second electrode having a first extension segment, and the first separator having a second extension segment; in the unfolding direction, both the first extension segment and the second extension segment extend toward the winding start side relative to the first start end, and the first extension segment and the second extension segment are fixedly connected.

[0006] Beneficial effects: The first extension of the second electrode extends beyond the first starting end of the first electrode towards the winding start side, and the second extension of the first separator extends beyond the first starting end of the first electrode towards the winding start side. By fixing the first extension and the second extension together, the second electrode and the first separator are tightly connected, effectively preventing the deformation of the second electrode caused by stress from creating gaps between the first and second electrodes. This reduces the risk of lithium plating in a single cell, helps prevent the formation of lithium dendrites, avoids internal short circuits, and significantly improves the safety, cycle stability, and lifespan of the battery.

[0007] In one alternative embodiment, the electrode assembly further has a winding center, with the second electrode located on a side near the winding center relative to the first electrode; the electrode assembly also includes a second diaphragm located on the side of the second electrode near the winding center, and the second diaphragm is stacked and wound around the second electrode, the first diaphragm, and the first electrode; the second diaphragm has a third extension, which extends toward the winding start side relative to the first starting end in the unfolding direction, and at least one of the third extension and the second extension extends beyond the first extension toward the winding start side.

[0008] Beneficial effects: A second separator is provided on the inner side of the second electrode. The third extension of the second separator extends beyond the first extension towards the winding start side. The third extension can restrict the position of the first extension of the second electrode and can also prevent the second electrode from deforming inward to a certain extent. Furthermore, the third extension of the second separator and / or the first extension of the first separator can fill the central hole of the electrode assembly, reducing or eliminating the space provided for the deformation of the second electrode. This helps to prevent local lithium-ion deposition caused by the deformation of the second electrode, reduce the risk of lithium plating, and thus improve the safety performance of the battery.

[0009] In one alternative embodiment, both the third extension and the second extension extend beyond the first extension towards the winding start side; the first extension is also fixed to the third extension.

[0010] Beneficial effects: The second extension of the first diaphragm and the third extension of the second diaphragm can better fill the central hole of the electrode assembly, which can significantly reduce the porosity of the central region of the electrode assembly, thereby effectively limiting the deformation space of the second electrode, improving the adhesion between the first and second electrodes and the diaphragm, and helping to improve the stability of the electrochemical performance of the cell; at the same time, the first extension and the third extension are also fixed, so that the deformation of the second electrode is bound and limited by the first and second diaphragms together.

[0011] In one alternative embodiment, the electrode assembly further includes an adhesive element that connects the first extension and the second extension.

[0012] Beneficial effects: The adhesive can firmly connect the first extension section and the second extension section, and the connection between the second electrode and the first separator is tighter, which significantly reduces the risk of lithium plating during battery cycling and improves safety performance.

[0013] In one optional embodiment, the adhesive includes a base layer, a first adhesive layer, and a second adhesive layer. The base layer has a first surface and a second surface disposed opposite to each other along its thickness direction. The first adhesive layer is disposed on the first surface, and the second adhesive layer is disposed on the second surface. The adhesive is located between a first extension segment and a second extension segment in the thickness direction of the base layer. The first adhesive layer is connected to the first extension segment, and the second adhesive layer is connected to the second extension segment.

[0014] Beneficial effects: By using the base layer as an intermediate support structure, the mechanical connection strength between the first and second extension sections is enhanced, preventing breakage or misalignment during subsequent hot pressing, encapsulation, or transportation. The adhesive layers on both sides bond the second electrode and the first separator, ensuring a uniform and tight bonding interface between them, reducing voids or air bubbles, and improving the interface consistency within the electrode assembly, thereby enhancing the battery's ion transport efficiency and cycle stability.

[0015] In one optional embodiment, the adhesive includes a base layer, a first adhesive layer, and a second adhesive layer. The base layer has a first surface and a second surface disposed opposite to each other along its thickness direction. The first adhesive layer is disposed on the first surface, and the second adhesive layer is disposed on the second surface. The adhesive is arranged in a strip shape and is wound around a first extension section. A portion of the adhesive is located between the first extension section and the second extension section, and another portion of the adhesive is located between the first extension section and the third extension section. The first adhesive layer is connected to the first extension section, and the second adhesive layer is connected to either the second extension section or the third extension section.

[0016] Beneficial effects: By connecting the second electrode to the first and second diaphragms using adhesive, the bonding strength between the second electrode and the first and second diaphragms is improved. Furthermore, the integrated fixing of multiple layers of material in the thickness and circumferential directions is achieved, effectively preventing misalignment, wrinkles, and other defects during winding. In addition, the wrapping bonding of the first extension section with adhesive can suppress the deformation of the second electrode caused by stress release, further improving the structural stability and manufacturing consistency of the electrode assembly.

[0017] In one alternative embodiment, the electrode assembly further has a height direction perpendicular to the unfolding direction, a first extension has a first edge, a second extension has a second edge, the second edge and the first edge are both located on the same side of the electrode assembly in the height direction and are spaced apart; an adhesive is attached to the first extension and connected to the second extension, a portion of the adhesive is located between the first edge and the second edge, and the adhesive is located on the side of the first extension away from the second extension in the thickness direction of the adhesive.

[0018] Beneficial effects: The bonding of the same side surface of the adhesive to the second electrode and the first separator simplifies the bonding structure, reduces the assembly difficulty, and enhances the coplanar bonding effect between the second electrode and the first separator. This not only effectively suppresses the deformation behavior of the second electrode caused by stress release during the winding process, but also improves the interface contact quality and reduces the risk of lithium plating caused by abnormal increase in local current density, thereby improving the structural stability of the electrode assembly and the safety performance of the battery.

[0019] In one alternative implementation, the adhesive is spaced apart from the first starting end in the unfolding direction.

[0020] Beneficial effects: By spacing the adhesive part at a certain distance from the first starting end, the adhesive part is prevented from covering the first starting end of the first electrode sheet, which would affect the natural adhesion between the first electrode sheet and the first diaphragm on the winding starting side, causing wrinkles, bubbles or misalignment. This improves the adhesion consistency between the first electrode sheet and the first diaphragm on the winding starting side, and can also effectively alleviate edge cracking or adhesion failure caused by stress concentration, further enhancing the structural stability and manufacturing reliability of the electrode assembly.

[0021] In one optional embodiment, the single cell is a cylindrical cell; the single cell also includes a housing, an electrode assembly disposed within the housing, a first electrode being a positive electrode, and a second electrode being a negative electrode; the electrode assembly also has a winding end side, the winding end side and the winding start side being located on opposite sides in the unfolding direction; in the unfolding direction, the first separator extends beyond the first electrode and the second electrode towards the winding end side.

[0022] Beneficial effects: By extending beyond both the first and second electrodes on both the winding end and winding start sides, the first separator ensures that the beginning and end of both the positive and negative electrodes are completely covered by the first separator, avoiding internal short circuits caused by electrode misalignment or edge warping, and significantly improving battery safety. The casing provides a stable encapsulation space for the electrode components and electrolyte, effectively preventing damage to the internal structure from external impacts and vibrations, and enhancing the overall mechanical strength and structural integrity of the battery.

[0023] Secondly, this utility model also provides a battery pack, including the aforementioned single battery cell. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a perspective view of a single battery cell according to an embodiment of the present utility model;

[0026] Figure 2 for Figure 1 A top view of the electrode assembly of the single cell shown;

[0027] Figure 3 for Figure 2 The diagram shows the unfolded structure of the electrode assembly.

[0028] Figure 4 for Figure 3An exploded view of the electrode assembly shown.

[0029] Figure 5 This is a schematic diagram of the unfolded structure of the electrode assembly of another single-cell battery according to an embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 100. Electrode assembly; 1001. Winding start side; 1002. Winding end side;

[0032] 110. First electrode; 1101. First starting end;

[0033] 120. First diaphragm; 1201. Second extension section; 1202. Second edge;

[0034] 130. Second pole piece; 1301. First extension section; 1302. First edge; 1303. Second starting end;

[0035] 140. Second diaphragm; 1401. Third extension section;

[0036] 150. Adhesive components;

[0037] 160. Housing; 1601. Housing body; 1602. Housing cover; 1603. Pole post assembly. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0039] The following is combined Figures 1 to 5 The following describes embodiments of the present invention.

[0040] According to an embodiment of the present invention, in one aspect, a single-cell battery is provided, comprising: an electrode assembly 100, the electrode assembly 100 including a first electrode 110, a first separator 120 and a second electrode 130 stacked and wound together, the first separator 120 being located between the first electrode 110 and the second electrode 130, the electrode assembly 100 having an unfolding direction L and a winding start side 1001 located in the unfolding direction L; the first electrode 110 having a first start end 1101 located in the winding start side 1001, the second electrode 130 having a first extension section 1301, and the first separator 120 having a second extension section 1201; in the unfolding direction L, both the first extension section 1301 and the second extension section 1201 extend toward the winding start side 1001 relative to the first start end 1101, and the first extension section 1301 and the second extension section 1201 are fixedly connected.

[0041] In the single-cell battery of this embodiment, the first extension 1301 of the second electrode 130 extends beyond the first starting end 1101 of the first electrode 110 towards the winding start side 1001, and the second extension 1201 of the first separator 120 extends beyond the first starting end 1101 of the first electrode 110 towards the winding start side 1001. The first extension 1301 and the second extension 1201 are fixed together, so that the second electrode 130 and the first separator 120 are tightly connected. This effectively avoids the deformation of the second electrode 130 caused by stress, which would cause a gap between the first electrode 110 and the second electrode 130. This reduces the risk of lithium plating in the single-cell battery, helps prevent the formation of lithium dendrites, avoids internal short circuits, and significantly improves the safety, cycle stability and service life of the battery.

[0042] In one embodiment, such as Figure 2 and Figure 4 As shown, the electrode assembly 100 also has a winding center O, and the second electrode 130 is located on the side near the winding center O relative to the first electrode 110; the electrode assembly 100 also includes a second diaphragm 140, which is located on the side of the second electrode 130 near the winding center O, and the second diaphragm 140 is stacked and wound with the second electrode 130, the first diaphragm 120 and the first electrode 110; the second diaphragm 140 has a third extension 1401, which extends toward the winding start side 1001 relative to the first starting end 1101 in the unfolding direction L, and at least one of the third extension 1401 and the second extension 1201 extends beyond the first extension 1301 toward the winding start side 1001.

[0043] A second separator 140 is provided inside the second electrode 130. The third extension 1401 of the second separator 140 extends beyond the first extension 1301 toward the winding start side 1001. The third extension 1401 and the first extension 1301 of the second electrode 130 can restrict the position of the first extension 1301 of the second electrode 130 and can also prevent the second electrode 130 from deforming inward to a certain extent. Furthermore, the third extension 1401 of the second separator 140 and / or the first extension 1301 of the first separator 120 can fill the central hole of the electrode assembly 100, reducing or eliminating the space provided for the deformation of the second electrode 130. This helps to prevent local lithium-ion deposition caused by the deformation of the second electrode 130, reduce the risk of lithium plating, and thus improve the safety performance of the battery.

[0044] In one embodiment, such as Figure 4 As shown, the third extension segment 1401 and the second extension segment 1201 both extend beyond the first extension segment 1301 toward the winding start side 1001; the first extension segment 1301 is also fixed to the third extension segment 1401.

[0045] The second extension 1201 of the first diaphragm 120 and the third extension 1401 of the second diaphragm 140 can better fill the central hole of the electrode assembly 100, significantly reducing the porosity in the central region of the electrode assembly 100. This effectively limits the deformation space of the second electrode 130, improves the adhesion between the first electrode 110, the second electrode 130, and the diaphragm, and helps to improve the electrochemical performance stability of the battery cell. In addition, the first extension 1301 and the third extension 1401 are also fixed, so that the first diaphragm 120 and the second diaphragm 140 jointly bind and limit the deformation of the second electrode 130.

[0046] In one embodiment, such as Figure 3 and Figure 4 As shown, the electrode assembly 100 also includes an adhesive 150, which connects the first extension 1301 and the second extension 1201.

[0047] The adhesive 150 can firmly connect the first extension 1301 and the second extension 1201, and the connection between the second electrode 130 and the first separator 120 is tighter, which significantly reduces the risk of lithium plating during battery cycling and improves safety performance.

[0048] There are several ways to connect the first extension section 1301 and the second extension section 1201 with the adhesive 150. Three simple examples are given below.

[0049] The first type: The adhesive 150 includes a base layer, a first adhesive layer, and a second adhesive layer. The base layer has a first surface and a second surface disposed opposite to each other along its thickness direction. The first adhesive layer is disposed on the first surface, and the second adhesive layer is disposed on the second surface. The adhesive 150 is located between the first extension segment 1301 and the second extension segment 1201 in the thickness direction of the base layer. The first adhesive layer is connected to the first extension segment 1301, and the second adhesive layer is connected to the second extension segment 1201. By using the base layer as an intermediate support structure, the mechanical connection strength between the first extension segment 1301 and the second extension segment 1201 is enhanced, preventing problems such as breakage and misalignment during subsequent hot pressing, encapsulation, or transportation. By bonding the second electrode 130 and the first separator 120 with the two adhesive layers, a uniform and tight bonding interface can be formed between the second electrode 130 and the first separator 120, reducing the presence of voids or air bubbles. This is beneficial to improving the interface consistency inside the electrode assembly 100, thereby improving the ion transport efficiency and cycle stability of the battery.

[0050] The second type: The adhesive 150 includes a base layer, a first adhesive layer, and a second adhesive layer. The base layer has a first surface and a second surface disposed opposite to each other along its thickness direction. The first adhesive layer is disposed on the first surface, and the second adhesive layer is disposed on the second surface. The adhesive 150 is arranged in a strip shape and is wound around the first extension section 1301. A portion of the adhesive 150 is located between the first extension section 1301 and the second extension section 1201, and another portion of the adhesive 150 is located between the first extension section 1301 and the third extension section 1401. The first adhesive layer and... The first extension segment 1301 is connected, and the second adhesive layer is connected to the second extension segment 1201 or the third extension segment 1401. At this time, the adhesive component 150 is wrapped around the first extension segment 1301, and the second electrode 130 is connected to the first diaphragm 120 and the second diaphragm 140 through the adhesive component 150. This not only improves the bonding strength between the second electrode 130 and the first diaphragm 120 and the second diaphragm 140, but also achieves integrated fixation of multi-layer materials in the thickness direction and circumferential direction, effectively preventing misalignment, wrinkles and other defects during the winding process. In addition, the wrapping bonding of the adhesive component 150 to the first extension segment 1301 can also suppress the deformation behavior of the second electrode 130 caused by stress release, further improving the structural stability and manufacturing consistency of the electrode assembly 100.

[0051] The third type: such as Figure 5As shown, the electrode assembly 100 also has a height direction Z perpendicular to the unfolding direction L. The first extension 1301 has a first edge 1302, and the second extension 1201 has a second edge 1202. The second edge 1202 and the first edge 1302 are both located on the same side of the electrode assembly 100 in the height direction Z and are spaced apart. The adhesive 150 is attached to the first extension 1301 and connected to the second extension 1201. A portion of the adhesive 150 is located between the first edge 1302 and the second edge 1202, and the adhesive 150 is located on the side of the first extension 1301 away from the second extension 1201 in the thickness direction of the adhesive 150. The adhesive component 150 is bonded to the second electrode 130 and the first separator 120 on the same side surface, which simplifies the bonding structure, reduces the assembly difficulty, and enhances the coplanar bonding effect between the second electrode 130 and the first separator 120. This not only effectively suppresses the deformation behavior of the second electrode 130 caused by stress release during the winding process, but also improves the interface contact quality and reduces the risk of lithium plating caused by abnormal increase in local current density, thereby improving the structural stability of the electrode assembly 100 and the safety performance of the battery.

[0052] In one embodiment, such as Figure 3 As shown, in the unfolding direction L, the adhesive 150 is spaced apart from the first starting end 1101. By maintaining a certain distance between the adhesive 150 and the first starting end 1101, the adhesive 150 is prevented from covering the first starting end 1101 of the first electrode 110, which would affect the natural adhesion between the first electrode 110 and the first diaphragm 120 on the winding starting side 1001, causing wrinkles, bubbles, or misalignment. This improves the adhesion consistency between the first electrode 110 and the first diaphragm 120 on the winding starting side 1001, and can also effectively alleviate edge cracking or adhesion failure caused by stress concentration, further enhancing the structural stability and manufacturing reliability of the electrode assembly 100.

[0053] It is understood that, in another embodiment, the adhesive 150 extends to the first starting end 1101 in the unfolding direction L.

[0054] In one embodiment, the second electrode 130 has a second starting end. In the unfolding direction, the distance D1 between the second starting end and the first starting end 1101 is 2mm-30mm. This distance allows the first electrode 110 to avoid the deformed portion of the second electrode 130, eliminating the gap between the first electrode 110 and the second electrode 130, thereby reducing the risk of lithium plating in the single cell, preventing the formation of lithium dendrites, avoiding internal short circuits, and significantly improving the safety, cycle stability and service life of the battery.

[0055] In one embodiment, such as Figure 1 and Figure 2 As shown, the single cell is a cylindrical cell. Figures 1 to 4 As shown, the single cell also includes a housing 160, and an electrode assembly 100 is disposed inside the housing 160. The first electrode 110 is a positive electrode, and the second electrode 130 is a negative electrode. The electrode assembly 100 also has a winding end side 1002, and the winding end side 1002 and the winding start side 1001 are located on opposite sides in the unfolding direction L. In the unfolding direction L, the first separator 120 extends beyond the first electrode 110 and the second electrode 130 toward the winding end side 1002.

[0056] By extending beyond the first electrode 110 and the second electrode 130 at both the winding end 1002 and winding start 1001, the first separator 120 ensures that the start and end ends of both the positive and negative electrodes are completely covered by the first separator 120. This prevents internal short circuits caused by electrode misalignment or edge warping, significantly improving battery safety. The housing 160 provides a stable encapsulation space for the electrode assembly 100 and electrolyte, effectively preventing damage to the internal structure from external impacts and vibrations, and enhancing the overall mechanical strength and structural integrity of the battery.

[0057] Furthermore, such as Figure 1 As shown, the housing 160 includes a housing body 1601 and a housing cover 1602. The housing body 1601 has an open receiving cavity, and the electrode assembly 100 is disposed inside the housing body 1601. The housing cover 1602 is located at the opening. The housing body 1601 and the housing cover 1602 not only facilitate the assembly of the electrode assembly 100, but also provide effective protection for the electrode assembly 100. The housing cover 1602 is provided with a pole post assembly 1603, and the pole post assembly 1603 and the housing 160 are electrically connected to two tabs of different polarities of the electrode assembly 100, respectively.

[0058] According to an embodiment of the present invention, another aspect provides a battery pack comprising the aforementioned single battery cell.

[0059] In one embodiment, the battery pack further includes a housing, a cover, etc. The housing has a receiving cavity, the cover is disposed in the housing and closes the receiving cavity, and the individual battery cells are disposed in the receiving cavity. The battery pack can be applied to electric vehicles, energy storage systems, portable electronic devices, etc.

[0060] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A single-cell battery, characterized in that, include: An electrode assembly (100) includes a first electrode (110), a first diaphragm (120), and a second electrode (130) stacked and wound together, the first diaphragm (120) being located between the first electrode (110) and the second electrode (130), the electrode assembly (100) having an unfolding direction (L) and a winding start side (1001) located in the unfolding direction (L); The first electrode (110) has a first starting end (1101) located on the winding starting side (1001), the second electrode (130) has a first extension section (1301), and the first diaphragm (120) has a second extension section (1201). In the unfolding direction (L), both the first extension section (1301) and the second extension section (1201) extend relative to the first starting end (1101) toward the winding starting side (1001), and the first extension section (1301) and the second extension section (1201) are fixedly connected.

2. The single-cell battery according to claim 1, characterized in that, The electrode assembly (100) further has a winding center (O), and the second electrode (130) is located on the side closer to the winding center (O) relative to the first electrode (110); the electrode assembly (100) further includes a second diaphragm (140), the second diaphragm (140) is located on the side of the second electrode (130) closer to the winding center (O), and the second diaphragm (140) is stacked and wound with the second electrode (130), the first diaphragm (120) and the first electrode (110); The second diaphragm (140) has a third extension (1401) that extends toward the winding start side (1001) relative to the first starting end (1101) in the unfolding direction (L), and at least one of the third extension (1401) and the second extension (1201) extends beyond the first extension (1301) toward the winding start side (1001).

3. The single-cell battery according to claim 2, characterized in that, Both the third extension segment (1401) and the second extension segment (1201) extend beyond the first extension segment (1301) toward the winding start side (1001); the first extension segment (1301) is also fixed to the third extension segment (1401).

4. The single-cell battery according to claim 2, characterized in that, The electrode assembly (100) further includes an adhesive (150) that connects the first extension section (1301) and the second extension section (1201).

5. The single-cell battery according to claim 4, characterized in that, The adhesive (150) includes a base layer, a first adhesive layer and a second adhesive layer. The base layer has a first surface and a second surface disposed opposite to each other along its thickness direction. The first adhesive layer is disposed on the first surface and the second adhesive layer is disposed on the second surface. The adhesive (150) is located between the first extension segment (1301) and the second extension segment (1201) in the thickness direction of the base layer, the first adhesive layer is connected to the first extension segment (1301), and the second adhesive layer is connected to the second extension segment (1201).

6. The single-cell battery according to claim 4, characterized in that, The adhesive (150) includes a base layer, a first adhesive layer and a second adhesive layer. The base layer has a first surface and a second surface disposed opposite to each other along its thickness direction. The first adhesive layer is disposed on the first surface and the second adhesive layer is disposed on the second surface. The adhesive (150) is arranged in a strip shape and is wound around the first extension section (1301). A portion of the adhesive (150) is located between the first extension section (1301) and the second extension section (1201), and another portion of the adhesive (150) is located between the first extension section (1301) and the third extension section (1401). The first adhesive layer is connected to the first extension section (1301), and the second adhesive layer is connected to the second extension section (1201) or the third extension section (1401).

7. The single-cell battery according to claim 4, characterized in that, The electrode assembly (100) also has a height direction (Z) perpendicular to the unfolding direction (L). The first extension segment (1301) has a first edge (1302), and the second extension segment (1201) has a second edge (1202). The second edge (1202) and the first edge (1302) are both located on the same side of the electrode assembly (100) in the height direction (Z) and are spaced apart. The adhesive (150) is attached to the first extension segment (1301) and connected to the second extension segment (1201). A portion of the adhesive (150) is located between the first edge (1302) and the second edge (1202), and the adhesive (150) is located on the side of the first extension segment (1301) away from the second extension segment (1201) in the thickness direction of the adhesive (150).

8. The single-cell battery according to claim 4, characterized in that, In the unfolding direction (L), the adhesive (150) is spaced apart from the first starting end (1101).

9. The single-cell battery according to any one of claims 1-8, characterized in that, The single cell is a cylindrical cell; the single cell also includes a housing (160), the electrode assembly (100) is disposed in the housing (160), the first electrode (110) is a positive electrode, and the second electrode (130) is a negative electrode; The electrode assembly (100) also has a winding end side (1002), the winding end side (1002) and the winding start side (1001) are located on opposite sides in the unfolding direction (L); in the unfolding direction (L), the first diaphragm (120) extends beyond the first electrode (110) and the second electrode (130) toward the winding end side (1002).

10. A battery pack, characterized in that, include: The single-cell battery according to any one of claims 1 to 9.

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