Secondary battery, manufacturing method for electrode assembly, and electronic device

Abstract

The present application discloses a secondary battery, a manufacturing method for an electrode assembly, and an electronic device. The secondary battery comprises an electrode assembly and a first tab. The electrode assembly comprises a first electrode sheet, a second electrode sheet, and a separator provided between the first electrode sheet and the second electrode sheet. The first electrode sheet, the second electrode sheet, and the separator are stacked and wound to form a wound structure. In the winding direction of the electrode assembly, the outermost electrode sheet in the electrode assembly is the first electrode sheet, the outermost section of the first electrode sheet is partially stacked in a first direction to form an overlapping structure, and the first direction is the stacking direction of both the second electrode sheet and the separator which are adjacent to the overlapping structure. The first tab is connected to the outermost section of the first electrode sheet, and in the winding direction of the electrode assembly, the overlapping structure is located on the side of the first tab close to the winding center of the electrode assembly. The present application facilitates the reduction of the risk of damage to the first electrode sheet.

Description

[Amended to Rule 26 on May 29, 2026] Manufacturing methods for secondary batteries, electrode assemblies, and electronic devices [Amended according to Rule 26, dated May 2026] Technical Field

[0001] [Amended according to Rule 26 29.05.2026] This application relates to the field of energy storage technology, and in particular to a secondary battery, a method for manufacturing an electrode assembly, and an electronic device. [Amended according to Rule 26, May 29, 2026] Background Technology

[0002] [Amended according to Rule 26, dated May 2026, 2029] In related technologies, secondary batteries include electrode assemblies and tabs. Electrode assemblies include stacked electrode sheets and a separator. The electrode sheets are connected to the tabs, and the tabs are connected to an external structure. Electrode assemblies are typically classified into wound structures and stacked structures. In wound electrode assemblies, the electrode assembly expands during charge-discharge cycles. This expansion causes stress on the electrode sheets, posing a risk of damage to weaker parts of the electrode sheets. [Amended according to Rule 26, May 29, 2026] Summary of the Invention

[0003] [Amended according to Rule 26 29.05.2026] The inventors found in related research that after the electrode is connected to the tab (e.g., by welding), the structural strength of the connection position of the electrode decreases. Furthermore, the closer the connection position of the tab and the electrode is to the outermost ring, the greater the tensile force that the connection position of the tab and the electrode experiences when the electrode assembly expands, which makes the electrode connected to the tab more susceptible to damage.

[0004] [Amended according to Rule 26 29.05.2026] In view of this, this application provides a secondary battery that helps reduce the risk of damage at the connection between the outermost electrode and the tab.

[0005] [Amended according to Rule 26, 29.05.2026] In a first aspect, this application provides a secondary battery, which includes an electrode assembly and a first tab. The electrode assembly includes a first electrode, a second electrode, and a separator disposed between the first and second electrodes. The first electrode, the second electrode, and the separator are stacked and wound to form a wound structure. Along the winding direction of the electrode assembly, the outermost electrode of the electrode assembly is the first electrode, and the outermost ring of the first electrode is partially stacked along a first direction to form an overlapping structure. The first direction is the stacking direction of the second electrode and the separator adjacent to the overlapping structure. Along the thickness direction of the first tab, the projections of the electrodes of the overlapping structure at least partially overlap. The first tab is connected to the outermost ring of the first electrode, and along the winding direction of the electrode assembly, the overlapping structure is located on the side of the first tab near the winding center of the electrode assembly.

[0006] [Amended according to Rule 26, 29.05.2026] In the above embodiment, the outermost ring of the first electrode sheet is provided with an overlapping structure. Along the winding direction of the electrode assembly, the overlapping structure is located on the side of the first tab near the winding center of the electrode assembly. This allows the overlapping structure to be stretched first when the electrode assembly expands, gradually unfolding, which helps reduce the stress at the connection between the first electrode sheet and the first tab, thus providing a margin for the expansion of the electrode assembly and reducing the risk of damage to the outermost ring of the first electrode sheet. Furthermore, the overlapping structure acts as a buffer at the connection between the first electrode sheet and the first tab in the event of a drop of the secondary battery, further reducing the risk of damage to the outermost ring of the first electrode sheet.

[0007] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the first electrode includes a first current collector and a first active material layer stacked together. Along the winding direction of the electrode assembly, the first current collector includes a first coated area with the first active material layer and a first empty foil area without the first active material layer. The first electrode tab is connected to the first empty foil area, and a portion of the first empty foil area is folded to form an overlapping structure.

[0008] [Amended according to Rule 26, 29.05.2026] In the above embodiments, the overlapping structure is disposed in the first empty foil area, which reduces the interference of the active material layer on the formation of the overlapping structure. Furthermore, compared with disposing of the overlapping structure in the part where the active material layer is provided, disposing of the overlapping structure in the first empty foil area is also beneficial to reducing the risk of the active material layer peeling off.

[0009] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the overlapping structure includes a first folded portion. The first folded portion includes a first segment, a second segment, and a third segment connected in sequence, wherein the second segment is bent relative to the first segment, the third segment is bent relative to the second segment, and the first segment, the second segment, and the third segment are stacked in sequence along a first direction. Along the first direction, the projections of the first segment, the second segment, and the third segment overlap.

[0010] [Amended according to Rule 26, 29.05.2026] In the above embodiment, when the electrode assembly expands, the first electrode sheet between the bend of the second segment relative to the first segment and the bend of the third segment relative to the second segment is first stretched, causing the first fold to gradually unfold. This helps to reduce the force at the connection between the first electrode sheet and the first tab, thereby providing a margin for the expansion of the electrode assembly and helping to reduce the risk of damage to the outermost ring of the first electrode sheet.

[0011] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the overlapping structure further includes a second fold portion, located between the first fold portion and the first electrode tab along the winding direction of the electrode assembly. The second fold portion includes a fourth segment, a fifth segment, and a sixth segment connected in sequence, with the fifth segment bent relative to the fourth segment and the sixth segment bent relative to the fifth segment. The fourth, fifth, and sixth segments are stacked sequentially along the thickness direction of the first electrode tab. Along the first direction, the projections of the fourth segment, the fifth segment, and the sixth segment overlap.

[0012] [Amended according to Rule 26, 29.05.2026] In the above embodiments, when the electrode assembly expands, the first electrode sheet between the bend of the fifth segment relative to the fourth segment and the bend of the sixth segment relative to the fifth segment is first stretched, causing the second fold to gradually unfold. This helps reduce the stress at the connection between the first electrode sheet and the first tab, thereby providing a margin for the expansion of the electrode assembly and reducing the risk of damage to the outermost ring of the first electrode sheet. In embodiments with a first fold and a second fold, only at least one of the first fold and the second fold needs to be fully extended or partially opened to reduce the risk of damage to the outermost ring of the first electrode sheet and improve the reliability of the overlapping structure.

[0013] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the stacking direction of the first, second and third segments is the same as the stacking direction of the fourth, fifth and sixth segments, and the sixth segment is connected to the third segment.

[0014] [Revised according to Rule 26, 29.05.2026] In the above embodiment, the sixth segment is connected to the third segment so that the folding directions of the first fold and the second fold are opposite. The first fold and the second fold with this shape can be formed by pressing out the first electrode sheet and then flattening the protrusion, which is beneficial to the forming of the first fold and the second fold.

[0015] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, along the winding direction of the electrode assembly, the distance between the bend of the second segment relative to the first segment and the bend of the third segment relative to the second segment is L1, and the distance between the bend of the fifth segment relative to the fourth segment and the bend of the fifth segment relative to the sixth segment is L2, satisfying L2 > L1.

[0016] [Revised according to Rule 26, 29.05.2026] In the above embodiment, the distance between the second fold and the first tab is closer than the distance between the first fold and the first tab. In the event of a secondary battery drop, the electrode assembly is subjected to instantaneous impact. When the condition L2 > L1 is met, the opened second fold is more conducive to dispersing the stress at the connection between the first electrode and the first tab.

[0017] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the maximum outer diameter that the electrode assembly can expand to is D1, the minimum outer diameter of the electrode assembly is D2, and along the winding direction of the electrode assembly, the distance between the bend of the second segment relative to the first segment and the bend of the third segment relative to the second segment is L1, and the distance between the bend of the fifth segment relative to the fourth segment and the bend of the fifth segment relative to the sixth segment is L2, satisfying 2(L1+L2)≥π(D1-D2).

[0018] [Revised according to Rule 26, 29.05.2026] In the above embodiments, when L1+L2 satisfies the condition L≥π(D1-D2) / 2, it is beneficial to increase the expansion margin of the electrode assembly, and to further reduce the force on the outermost first electrode connection position when the electrode assembly expands, thereby further reducing the risk of damage to the first electrode.

[0019] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, along the winding direction of the electrode assembly, the distance between the bend of the second segment relative to the first segment and the bend of the third segment relative to the second segment is L1, which satisfies 0.1mm≤L1. This is beneficial to reduce the stress on the outermost first electrode connection position when the electrode assembly expands, thereby reducing the risk of damage to the first electrode.

[0020] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the distance between the bend of the fifth segment relative to the fourth segment and the bend of the fifth segment relative to the sixth segment is L2, which satisfies 0.1mm≤L2. This is beneficial to reduce the stress on the outermost first electrode connection position when the electrode assembly expands, thereby reducing the risk of damage to the first electrode.

[0021] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, along the winding direction of the electrode assembly, the distance between the bend of the second segment relative to the first segment and the bend of the third segment relative to the second segment is L1, and the distance between the bend of the fifth segment relative to the fourth segment and the bend of the fifth segment relative to the sixth segment is L2, satisfying 0.2mm≤L1+L2. This is beneficial to reducing the stress on the outermost first electrode connection position when the electrode assembly expands, thereby reducing the risk of damage to the first electrode.

[0022] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, L1+L2≤3mm is satisfied, which will prevent the portion reserved for the first electrode sheet to be stretched when the electrode assembly expands from being too long. This is beneficial to reducing the space occupied by the overlapping structure and also beneficial to the processing and forming of the overlapping structure.

[0023] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the secondary battery further includes a second tab. The second electrode includes a second current collector and a second active material layer stacked together. Along the winding direction of the electrode assembly, the second current collector includes a second coated area with the second active material layer and a second empty foil area without the second active material layer. Along the winding direction of the electrode assembly, the electrode of the second outermost ring of the electrode assembly includes a second electrode, and the outermost ring of the second electrode includes a second empty foil area. The second tab is connected to the second empty foil area of ​​the outermost ring of the second electrode. Along the winding direction of the electrode assembly, the projection of the overlapping structure is located between the projection of the first tab and the projection of the second tab. The projection direction of the overlapping structure, the projection direction of the first tab, and the projection direction of the second tab are the thickness direction of the first tab.

[0024] [Amended according to Rule 26, 29.05.2026] In the above embodiments, in the winding structure of the electrode assembly, the diameters of the first and second tabs are relatively large. During the expansion of the electrode assembly, the first and second tabs first contact and abut against the casing of the secondary battery, resulting in greater compressive force between the layers at the first and second tabs. When the projection of the overlapping structure is located between the projections of the first and second tabs, it is beneficial to increase the area of ​​initial contact between the electrode assembly and the casing, which helps to reduce the risk of internal collapse of the electrode assembly due to local stress concentration between the electrode assembly and the casing, thereby improving the interface performance of the electrode assembly and reducing the risk of cycle degradation of the secondary battery. In one or more embodiments of this application, along the winding direction of the electrode assembly, the length of the overlapping structure is L, and the minimum distance between the first and second tabs is T, satisfying 0.04T≤L≤T.

[0025] [Revised according to Rule 26, 29.05.2026] In the above embodiments, in the winding structure of the electrode assembly, the diameters at the first and second tabs are relatively large. During the expansion of the electrode assembly, the extrusion pressure between the layers at the first and second tabs is relatively large. When 0.04T≤L≤T is satisfied, on the one hand, the overall length of the overlapping structure is not too small, which helps to increase the area of ​​the electrode assembly in initial contact with the shell, reducing the risk of internal collapse of the electrode assembly due to local stress concentration between the electrode assembly and the shell, thereby improving the interface performance of the electrode assembly and reducing the risk of cycle degradation of the secondary battery. On the other hand, the overall length of the overlapping structure is not too large, which helps to reduce the risk of overlap between the overlapping structure and the second tab along the stacking direction of the first electrode, the separator, and the second electrode, thereby reducing the risk of the overlapping structure being squeezed and difficult to disperse or unfold. It also helps to reduce the influence of the interface between the first and second electrodes and electrolyte wetting, reducing the possibility of deterioration of the cycle performance of the secondary battery.

[0026] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the minimum distance between the fourth segment and the first tab along the winding direction of the electrode assembly is between 1 and 10 mm.

[0027] [Revised according to Rule 26, 29.05.2026] In the above embodiment, the distance between the connection point of the first electrode and the first tab and the fourth segment is not too far, which helps to reduce the stress at the connection point of the first electrode and the first tab, thereby further reducing the risk of damage to the outermost ring of the first electrode; it also ensures that the distance between the connection point of the first electrode and the first tab and the fourth segment is not too close, which helps to provide space for the formation of the overlapping structure and helps to reduce the risk of interference between the overlapping structure and the tab.

[0028] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the first electrode further includes a seventh segment and an eighth segment. Along the winding direction of the electrode assembly, the seventh segment is connected to the first segment, and the eighth segment is connected to the fourth segment. The secondary battery further includes a first adhesive member, which is bonded to both the seventh and eighth segments, and is also bonded to the overlapping structure.

[0029] [Amended according to Rule 26, 29.05.2026] In the above embodiments, the first adhesive component plays a role in fixing the morphology of the overlapping structure, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling during the winding process. Furthermore, in the event of an accident such as an impact on the electrode assembly, the overlapping structure may be subjected to compression or impact. The first adhesive component helps to maintain the morphology of the overlapping structure, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling before the electrode assembly expands.

[0030] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the first adhesive member is also bonded to the first tab.

[0031] [Amended according to Rule 26, 29.05.2026] In the above embodiments, the first adhesive component serves to fix the first electrode tab, which helps to reduce the risk of the first electrode tab detaching from or partially detaching from the first electrode sheet, reduces the risk of damage to the first electrode sheet, and also reduces the possibility of the first electrode tab piercing the diaphragm and coming into contact with an electrode sheet of different polarity. Furthermore, bonding the first adhesive component together with the first electrode tab and the overlapping structure helps to save on adhesive application processes.

[0032] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, along the width direction of the first electrode sheet, the first electrode tab is connected to the first electrode sheet and extends beyond the first electrode sheet. Along the direction in which the first electrode tab extends, the first adhesive member extends beyond the first electrode sheet.

[0033] [According to Rule 26, amended 29.05.2026] In the above embodiments, along the direction in which the first tab extends, the first adhesive extends beyond the first electrode sheet, which helps to reduce the possibility of the separator being punctured and short-circuited at the overlapping structure, and helps to improve the safety of the secondary battery.

[0034] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the secondary battery further includes a housing, an electrode assembly disposed within the housing, and an electrolyte disposed within the housing. The peel strength between the first adhesive and the seventh segment is F1, satisfying 0 N / mm ≤ F1 ≤ 0.08 N / mm.

[0035] [Revised according to Rule 26, 29.05.2026] In the above embodiments, when F1 = 0, the peel strength between the first adhesive and the seventh segment before immersion in the electrolyte is greater than 0, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling during the winding process. When F1 satisfies the condition 0 N / mm < F1 ≤ 0.08 N / mm, on the one hand, the peel strength F1 between the first adhesive and the seventh segment is not too large, which helps to allow the first adhesive to peel smoothly from the seventh segment when the electrode assembly expands, reducing the risk that the first adhesive will affect the effect of the overlapping structure when the electrode assembly expands; on the other hand, the peel strength F1 between the first adhesive and the seventh segment is not too small, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling under impact or other conditions, and helps to improve the reliability of the overlapping structure.

[0036] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the secondary battery further includes a housing, an electrode assembly disposed within the housing, and an electrolyte disposed within the housing. The peel strength between the first adhesive and the overlapping structure is F2, satisfying 0 N / mm ≤ F2 ≤ 0.08 N / mm.

[0037] [Revised according to Rule 26, 29.05.2026] In the above embodiments, when F2 = 0, the peel strength between the second adhesive and the overlapping structure before immersion in the electrolyte is greater than 0, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling during the winding process. When F2 satisfies the condition 0 N / mm < F2 ≤ 0.08 N / mm, on the one hand, the peel strength F2 between the second adhesive and the overlapping structure is not too large, which helps to allow the second adhesive to peel smoothly from the overlapping structure when the electrode assembly expands, reducing the risk that the second adhesive will affect the effect of the overlapping structure when the electrode assembly expands; on the other hand, the peel strength F2 between the second adhesive and the overlapping structure is not too small, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling under impact or other conditions on the electrode assembly, and helps to improve the reliability of the overlapping structure.

[0038] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the secondary battery further includes a housing, an electrode assembly disposed within the housing, and an electrolyte disposed within the housing. The peel strength between the first adhesive and the eighth segment is F3, satisfying 0 N / mm ≤ F3 ≤ 0.08 N / mm.

[0039] [Revised according to Rule 26, 29.05.2026] In the above embodiments, when F3 = 0, the peel strength between the first adhesive and the eighth segment before immersion in electrolyte is greater than 0, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling during the winding process. When F3 satisfies the condition 0 N / mm < F2 ≤ 0.08 N / mm, on the one hand, the peel strength F3 between the first adhesive and the eighth segment is not too large, which helps to allow the first adhesive to peel smoothly from the eighth segment when the electrode assembly expands, reducing the risk that the first adhesive will affect the effect of the overlapping structure when the electrode assembly expands; on the other hand, the peel strength F3 between the first adhesive and the eighth segment is not too small, which helps to reduce the risk of the overlapping structure unraveling or partially unraveling under impact or other conditions, and helps to improve the reliability of the overlapping structure.

[0040] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the length of the first adhesive member along the winding direction of the electrode assembly is S1, which satisfies 2mm≤S1≤20mm.

[0041] [Revised according to Rule 26, 29.05.2026] In the above embodiments, when the length S1 of the first adhesive component satisfies the condition 2mm≤S1≤20mm, on the one hand, the area of ​​the first adhesive component is not too small, which is conducive to improving the bonding strength between the first adhesive component and the seventh segment, the overlapping structure and the eighth segment, reducing the risk of the overlapping structure coming apart during the winding process or when subjected to impact, and is conducive to improving the reliability of the overlapping structure; on the other hand, the area of ​​the first adhesive component is not too large, which is conducive to the smooth separation of the first adhesive component from the seventh segment, the overlapping structure and the eighth segment when the electrode assembly expands, reducing the risk that the first adhesive component will affect the effect of the overlapping structure when the electrode assembly expands.

[0042] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, 6mm≤S1≤13mm is satisfied.

[0043] [According to Rule 26, amended 29.05.2026] In the above embodiments, on the one hand, the area of ​​the first adhesive is not too small, which is conducive to improving the bonding strength between the first adhesive and the seventh segment, the overlapping structure and the eighth segment, and further reducing the risk of the overlapping structure coming apart during the winding process or when subjected to impact, and improving the reliability of the overlapping structure; on the other hand, the area of ​​the first adhesive is not too large, which is conducive to the smooth separation of the first adhesive from the seventh segment, the overlapping structure and the eighth segment when the electrode assembly expands, and further reducing the risk that the first adhesive will affect the effect of the overlapping structure when the electrode assembly expands.

[0044] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the material of the first adhesive includes at least one of acrylic resin, polypropylene, or rubber.

[0045] [Amended according to Rule 26 29.05.2026] In one or more embodiments of this application, the first electrode tab is welded to the first electrode plate.

[0046] [Amended according to Rule 26, 29.05.2026] In one or more embodiments of this application, the secondary battery further includes a housing, an electrode assembly disposed within the housing, and a portion of the first electrode tab extending out of the housing. The electrode assembly has a cylindrical structure, and the housing is a metal housing.

[0047] [Amended according to Rule 26, 29.05.2026] In the above embodiments, the cylindrical electrode assembly may rotate relative to the first tab when it expands. The folded portion is beneficial to suppress the stress on the first electrode and the first tab when the electrode assembly rotates, and to reduce the risk of damage to the outermost first electrode.

[0048] [Amended according to Rule 26, May 2026] In a second aspect, this application provides a method for manufacturing an electrode assembly of a secondary battery according to any of the above embodiments, comprising the following steps: stamping a first electrode sheet in an unfolded state using a round bar to form an arc-shaped protrusion; flattening the arc-shaped protrusion on the first electrode sheet to form an overlapping structure; and attaching and fixing the overlapping structure with adhesive. Then, stacking and winding the first electrode sheet, the second electrode sheet, and the separator in the unfolded state to form a winding structure, with the overlapping structure located at the outermost ring of the first electrode sheet.

[0049] [Amended according to Rule 26, 29.05.2026] In the above embodiments, when the electrode assembly expands, the overlapping structure is first stretched, causing it to gradually unfold. This helps reduce the stress at the connection between the first electrode and the first tab, thus providing a margin for the expansion of the electrode assembly and reducing the risk of damage to the outermost ring of the first electrode. Furthermore, adhesive bonding to fix the overlapping structure helps reduce the risk of it scattering or partially scattering during winding or when the electrode assembly is subjected to impact, thereby improving the reliability of the overlapping structure.

[0050] [Amended according to Rule 26 29.05.2026] In a third aspect, this application provides an electronic device comprising a secondary battery as described in any of the above embodiments.

[0051] [Amended according to Rule 26, 29.05.2026] In the above embodiments, the risk of damage to the outermost ring of the first electrode of the secondary battery is reduced, which is beneficial to improving the reliability of the secondary battery, and thus beneficial to improving the reliability of the electronic device.

[0052] [Amended according to Rule 26, May 2026] The secondary battery of this application includes an electrode assembly and a first tab. The outermost electrode of the electrode assembly is the first electrode, and the outermost edge of the first electrode is partially stacked to form an overlapping structure. The first tab is connected to the outermost edge of the first electrode. Along the winding direction of the electrode assembly, the overlapping structure is located on the side of the first tab closer to the winding center of the electrode assembly, so that when the electrode assembly expands, the overlapping structure is first stretched, and the overlapping structure gradually unfolds. This helps to reduce the stress at the connection between the first electrode and the first tab, thereby providing a margin for expansion of the electrode assembly and reducing the risk of damage to the outermost edge of the first electrode. [Revised according to Rule 26, May 29, 2026] Attachment Description

[0053] [Amended according to Rule 26, 29.05.2026] Figure 1 is a schematic diagram of the structure of a secondary battery provided in an embodiment of this application.

[0054] [Revised according to Rule 26, 29.05.2026] Figure 2 is an exploded view of the secondary battery in Figure 1.

[0055] [Amended according to Rule 26, 29.05.2026] Figure 3 is a schematic diagram of the structure of a secondary battery provided in another embodiment of this application.

[0056] [Amended according to Rule 26, 29.05.2026] Figure 4 is a schematic diagram of the wound electrode assembly and the first and second tabs in one embodiment of this application.

[0057] [Amended according to Rule 26, 29.05.2026] Figure 5 is a schematic diagram of the wound electrode assembly and the first and second tabs in another embodiment of this application.

[0058] [Amended according to Rule 26, 29.05.2026] Figure 6 is a side view of a portion of the first electrode and the first electrode tab provided in an embodiment of this application.

[0059] [Amended according to Rule 26, 29.05.2026] Figure 7 is a schematic diagram of the wound electrode assembly and the first and second tabs in another embodiment of this application.

[0060] [Amended according to Rule 26, 29.05.2026] Figure 8 is a partial side view of the first electrode and the first electrode tab provided in another embodiment of this application.

[0061] [Amended according to Rule 26, 29.05.2026] Figure 9 is a top view of a portion of the first electrode and the first electrode tab provided in an embodiment of this application.

[0062] [Amended according to Rule 26 29.05.2026] Figure 10 is a top view of a portion of the first electrode and the first electrode tab provided in another embodiment of this application.

[0063] [Amended according to Rule 26, 29.05.2026] Figure 11 is a bottom view of a portion of the first electrode and the first electrode tab provided in another embodiment of this application.

[0064] [Amended according to Rule 26, 29.05.2026] Figure 12 is a bottom view of a portion of the first electrode and the first electrode tab provided in another embodiment of this application.

[0065] [Amended according to Rule 26 29.05.2026] Figure 13 is a side view of the first adhesive member after unfolding according to an embodiment of this application.

[0066] [Amended according to Rule 26 29.05.2026] Figure 14 is a side view of the second adhesive member after unfolding according to an embodiment of this application.

[0067] [Amended according to Rule 26 29.05.2026] Figure 15 is a schematic diagram of an electronic device provided in an embodiment of this application.

[0068] [Revised according to Rule 26, May 29, 2026] Explanation of main component symbols: Secondary battery 100 Electrode assembly 10 First electrode 11 First current collector 111 First coating area 111a First empty foil area 111b First active material layer 112 Overlapping structure 113 First fold 1131 First segment 113a Second segment 113b Third segment 113c Second fold 1132 Fourth segment 113d Fifth segment 113e Sixth segment 113f Seventh segment 114 Eighth segment 116 Second electrode 12 Second current collector 121 Second coating area 121a Second empty foil area 121b Second active material layer 122 Separator 13 First tab 20 Second tab 30 Housing 40 First adhesive 50 Second adhesive 60 Winding direction of electrode assembly X First direction Y Width direction of first electrodeZ device main body 200 electronic devices 1000 [Revised according to Rule 26, May 2026] Detailed Implementation Method

[0069] [Revised according to Rule 26, 29.05.2026] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0070] [Amended according to Rule 26, May 29, 2026] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intervening component present. When a component is considered to be "located" to another component, it can be directly mounted on the other component or there may be an intervening component present.

[0071] [Amended 29.05.2026 in accordance with Rule 26] Unless otherwise stated, the term “multiple” as used herein means two or more.

[0072] [Amended according to Rule 26 on May 29, 2026] The terms “first”, “second”, etc. are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implying the number, specific order or primary and secondary relationship of the indicated technical features.

[0073] [Amended according to Rule 26, May 29, 2026] The term "perpendicular" is used to describe an ideal state between two components. In actual production or use, two components may be approximately perpendicular. For example, in numerical terms, perpendicular can refer to an angle between two straight lines within the range of 90° ± 10°, a dihedral angle between two planes within the range of 90° ± 10°, or an angle between a straight line and a plane within the range of 90° ± 10°.

[0074] [Amended according to Rule 26, May 29, 2026] The term "parallel" is used to describe an ideal state between two components. In actual production or use, two components may exist in a state that is approximately parallel. For example, in numerical terms, parallel can refer to the angle between two straight lines within the range of 180° ± 10°, parallel can also refer to the dihedral angle between two planes within the range of 180° ± 10°, and parallel can also refer to the angle between a straight line and a plane within the range of 180° ± 10°.

[0075] [Revised according to Rule 26, 29.05.2026] It should be noted that when a parameter is greater than, equal to or less than a certain endpoint value, it should be understood that the endpoint value is allowed to have a tolerance of ±5%.

[0076] [Amended according to Rule 26, May 2026] It should be understood that the dimensions of the structures shown in the accompanying drawings are provided for better understanding and convenience of description, and this application is not limited to the dimensions shown in the drawings. For clarity of the invention, elements irrelevant to the description have been omitted from the details of this specification.

[0077] [Amended according to Rule 26, 29.05.2026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0078] [Amended according to Rule 26, May 2026] In related technologies, when a secondary battery undergoes charge-discharge cycles, the electrode assembly expands. This expansion causes stress on the electrode, making the weakest parts of the electrode susceptible to damage. The inventors discovered in their research that after the electrode is connected to the tab (e.g., by welding), the structural strength at the connection point decreases. Furthermore, the closer the tab is to the outermost ring, the greater the tensile force experienced at the connection point during electrode assembly expansion, making the electrode connected to the tab more prone to damage.

[0079] [Amended according to Rule 26, dated May 2026] This application discloses a secondary battery, which includes an electrode assembly and a first tab. The electrode assembly includes a first electrode, a second electrode, and a separator disposed between the first and second electrodes. The first electrode, the second electrode, and the separator are stacked and wound to form a wound structure. Along the winding direction of the electrode assembly, the outermost electrode of the electrode assembly is the first electrode. The outermost ring of the first electrode is partially stacked along a first direction to form an overlapping structure. The first direction is the stacking direction of the second electrode and the separator adjacent to the overlapping structure. The first tab is connected to the outermost ring of the first electrode. Along the winding direction of the electrode assembly, the overlapping structure is located on the side of the first tab near the winding center of the electrode assembly.

[0080] [Amended according to Rule 26, dated May 2026] The outermost ring of the first electrode sheet is provided with an overlapping structure. Along the winding direction of the electrode assembly, the overlapping structure is located on the side of the first tab closest to the winding center of the electrode assembly. This allows the overlapping structure to be stretched first when the electrode assembly expands, gradually unfolding and reducing the stress at the connection between the first electrode sheet and the first tab. This provides a margin for expansion of the electrode assembly and helps reduce the risk of damage to the outermost ring of the first electrode sheet. Furthermore, the overlapping structure acts as a buffer at the connection between the first electrode sheet and the first tab in the event of a drop of the secondary battery, further reducing the risk of damage to the outermost ring of the first electrode sheet.

[0081] [Amended according to Rule 26, 29.05.2026] Some embodiments of this application will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0082] [Amended according to Rule 26, 29.05.2026] Please refer to Figures 1 and 2. An embodiment of this application provides a secondary battery 100, which includes an electrode assembly 10 and a first tab 20 connected to the electrode assembly 10.

[0083] [Amended according to Rule 26, 29.05.2026] In some embodiments, please refer to Figures 1 to 3. The secondary battery 100 can be a cylindrical battery, a square hard-shell battery, or a pouch battery. No specific limitations are made here.

[0084] [Amended according to Rule 26 29.05.2026] In some embodiments, referring to Figures 1 and 2, the secondary battery 100 further includes a second tab 30 connected to the electrode assembly 10, and the first tab 20 and the second tab 30 have different polarities.

[0085] [Amended according to Rule 26 29.05.2026] In some embodiments, please refer to Figures 1 and 2, the secondary battery 100 also includes a housing 40, and the electrode assembly 10 is disposed within the housing 40.

[0086] [Amended according to Rule 26 29.05.2026] In some embodiments, please refer to Figures 1 and 2, a portion of the first tab 20 extends out of the housing 40 and is used for electrical connection with an external structure, and a portion of the second tab 30 extends out of the housing 40 and is used for electrical connection with an external structure.

[0087] [Amended according to Rule 26, 29.05.2026] In some other embodiments, the first tab 20 is connected to a conductive first adapter (not shown), which extends out of the housing 40 and is used for electrical connection with an external structure. The second tab 30 is connected to a conductive second adapter (not shown), which extends out of the housing 40 and is used for electrical connection with an external structure.

[0088] [Amended according to Rule 26 29.05.2026] In some embodiments, housing 40 is a metal housing, and in other embodiments, housing 40 is a non-metallic housing.

[0089] [Amended according to Rule 26 29.05.2026] In some embodiments, the housing 40 includes at least one of a steel housing, a resin housing, or an aluminum-plastic film. For example, when the secondary battery 100 is a cylindrical battery or a square hard-shell battery, the housing 40 includes a steel housing or a resin housing, and when the secondary battery 100 is a soft-pack battery, the housing 40 includes an aluminum-plastic film.

[0090] [Amended according to Rule 26, 29.05.2026] In some embodiments, the housing 40 contains an electrolyte (not shown), which contains a lithium salt and a solvent. The lithium salt may include at least one of LiPF6, LiBF6, LiClO, LiB(CH3), LiCHSO4, LiCFSO4, LiN(SOCF), LiC(SOCF), or LiBOB. The solvent may be a carbonate compound, a carboxylic acid ester compound, an ether compound, other organic solvents, or a combination thereof.

[0091] [Amended according to Rule 26 29.05.2026] In some embodiments, please refer to Figures 4 and 5. The electrode assembly 10 includes a first electrode 11, a second electrode 12 and a separator 13 disposed between the first electrode 11 and the second electrode 12. The separator 13 is used to isolate the first electrode 11 and the second electrode 12. The first electrode 11, the second electrode 12 and the separator 13 are stacked and wound to form a wound structure.

[0092] [Amended according to Rule 26, 29.05.2026] In some embodiments, please refer to Figures 4 and 5, the electrode assembly 10 may be cylindrical or flat with arc-shaped portions at both ends.

[0093] [Amended according to Rule 26 29.05.2026] In some embodiments, please refer to Figures 4 and 5, the first electrode 11 includes a first current collector 111 and a first active material layer 112 stacked together, and the second electrode 12 includes a second current collector 121 and a second active material layer 122 stacked together.

[0094] [Amended according to Rule 26 29.05.2026] In some embodiments, referring to Figures 4 and 5, along the winding direction X of the electrode assembly 10, the first current collector 111 includes a first coated area 111a provided with a first active material layer 112 and a first empty foil area 111b not provided with the first active material layer 112.

[0095] [Revised according to Rule 26, 29.05.2026] The winding direction X of the electrode assembly 10 can be understood as the direction from the starting section of the winding of the electrode assembly 10 to the ending section of the winding of the electrode assembly 10.

[0096] [Amended according to Rule 26, 29.05.2026] In some embodiments, the first coating area 111a includes a first single-layer coating area (not shown) and a first double-layer coating area (not labeled). The first current collector 111 of the first single-layer coating area has a first active material layer 112 on one side in the thickness direction, and no first active material layer 112 on the other side. The first current collector 111 of the first double-layer coating area has a first active material layer 112 on both opposite sides in the thickness direction.

[0097] [Amended according to Rule 26 29.05.2026] In some embodiments, referring to Figures 4 and 5, along the winding direction X of the electrode assembly 10, the second current collector 121 includes a second coated area 121a provided with a second active material layer 122 and a second empty foil area 121b not provided with the second active material layer 122.

[0098] [Amended according to Rule 26, 29.05.2026] In some embodiments, the second coating area 121a includes a second single-layer coating area (not shown) and a second double-layer coating area (not identified). The second current collector 121 of the second single-layer coating area has a second active material layer 122 on one side in the thickness direction, and no second active material layer 122 on the other side. The second current collector 121 of the second double-layer coating area has a second active material layer 122 on both opposite sides in the thickness direction.

[0099] [Amended according to Rule 26, 29.05.2026] In some embodiments, the first current collector 111 is a cathode current collector, the second current collector 121 is an anode current collector, the first active material layer 112 is a cathode active material layer, and the second active material layer 122 is an anode active material layer.

[0100] [Amended according to Rule 26 29.05.2026] In some other embodiments, the first current collector 111 is an anode current collector, the second current collector 121 is a cathode current collector, the first active material layer 112 is an anode active material layer, and the second active material layer 122 is a cathode active material layer.

[0101] [Amended according to Rule 26, dated May 2026] The cathode current collector may be a metal layer comprising at least one of aluminum, nickel, tantalum, and titanium, such as aluminum foil. The anode current collector may be a metal layer comprising at least one of copper, nickel, tantalum, and titanium, such as copper foil. The cathode active material layer comprises a cathode active material, which may include at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate, or lithium manganese oxide. The anode active material layer comprises an anode active material, which may include at least one of graphite, hard carbon, soft carbon, silicon, silicon-oxygen materials, and silicon-carbon materials.

[0102] [Amended according to Rule 26, 29.05.2026] In some embodiments, the separator 13 is an insulating film material such as a polyethylene film, a polypropylene film, a polyester film, or a polyimide film.

[0103] [Revised according to Rule 26, 29.05.2026] In some embodiments, please refer to Figures 4 and 5, the first tab 20 is connected to the first electrode 11, the second tab 30 is connected to the second electrode 12, the polarity of the first tab 20 is the same as that of the first electrode 11, and the polarity of the second tab 30 is the same as that of the second electrode 12.

[0104] [Amended according to Rule 26, 29.05.2026] In some embodiments, the first tab 20 is welded to the first current collector 111, and the second tab 30 is welded to the second current collector 121.

[0105] [Amended according to Rule 26, 29.05.2026] In some embodiments, the material of the first tab 20 is the same as the material of the first current collector 111, and the material of the second tab 30 is the same as the material of the second current collector 121.

[0106] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to Figures 4 and 5, the outermost electrode of the electrode assembly 10 is a first electrode 11. The outermost edge of the first electrode 11 is partially stacked along a first direction Y to form an overlapping structure 113. The first direction Y is the stacking direction of the second electrode 12 and the separator 13 adjacent to the overlapping structure 113. A first tab 20 is connected to the outermost edge of the first electrode 11. Along the winding direction X of the electrode assembly 10, the overlapping structure 113 is located on the side of the first tab 20 near the winding center of the electrode assembly 10.

[0107] [Amended according to Rule 26, 29.05.2026] The outermost ring of the first electrode 11 is provided with an overlapping structure 113. Along the winding direction X of the electrode assembly 10, the overlapping structure 113 is located on the side of the first tab 20 near the winding center of the electrode assembly 10. This allows the overlapping structure 113 to be stretched first when the electrode assembly 10 expands, gradually unfolding the overlapping structure 113. This helps reduce the force at the connection between the first electrode 11 and the first tab 20, thus providing a margin for the expansion of the electrode assembly 10 and reducing the risk of damage to the outermost ring of the first electrode 11. Furthermore, the overlapping structure 113 acts as a buffer at the connection between the first electrode 11 and the first tab 20 in the event of a drop of the secondary battery 100, further reducing the risk of damage to the outermost ring of the first electrode 11.

[0108] [Revised according to Rule 26, 29.05.2026] In some embodiments, please refer to Figures 4 and 5. The first tab 20 is connected to the first empty foil area 111b. A portion of the first empty foil area 111b is folded to form an overlapping structure 113. The overlapping structure 113 is disposed in the first empty foil area 111b, which reduces the interference of the active material layer on the formation of the overlapping structure 113. Furthermore, compared to disposing of the overlapping structure 113 in the portion where the active material layer is provided, disposing of the overlapping structure 113 in the first empty foil area 111b is also beneficial to reducing the risk of the active material layer peeling off.

[0109] [Revised according to Rule 26, 29.05.2026] In some embodiments, please refer to Figures 4 and 6. The overlapping structure 113 includes a first fold 1131. The first fold 1131 includes a first segment 113a, a second segment 113b, and a third segment 113c connected in sequence. The second segment 113b is bent relative to the first segment 113a, and the third segment 113c is bent relative to the second segment 113b. The first segment 113a, the second segment 113b, and the third segment 113c are stacked in sequence along the first direction Y.

[0110] [Amended according to Rule 26 29.05.2026] When the electrode assembly 10 expands, the first electrode 11 between the bend of the second segment 113b relative to the first segment 113a and the bend of the third segment 113c relative to the second segment 113b is first stretched, causing the first folded portion 1131 to gradually unfold. This helps to reduce the force at the connection between the first electrode 11 and the first electrode tab 20, thereby providing a margin for the expansion of the electrode assembly 10 and helping to reduce the risk of damage to the outermost ring of the first electrode 11.

[0111] [Revised according to Rule 26, 29.05.2026] In some embodiments, referring to Figures 4 and 6, along the first direction Y, the projections of the first segment 113a, the second segment 113b, and the third segment 113c overlap.

[0112] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to Figures 4 and 6, the overlapping structure 113 further includes a second fold 1132 located between the first fold 1131 and the first tab 20 along the winding direction X of the electrode assembly 10. The second fold 1132 includes a fourth segment 113d, a fifth segment 113e, and a sixth segment 113f connected in sequence. The fifth segment 113e is bent relative to the fourth segment 113d, and the sixth segment 113f is bent relative to the fifth segment 113e. The fourth segment 113d, the fifth segment 113e, and the sixth segment 113f are stacked sequentially along the first direction Y.

[0113] [Amended according to Rule 26 29.05.2026] When the electrode assembly 10 expands, the first electrode 11 between the bend of the fifth segment 113e relative to the fourth segment 113d and the bend of the sixth segment 113f relative to the fifth segment 113e is first stretched, causing the second folded portion 1132 to gradually unfold. This helps to reduce the force at the connection between the first electrode 11 and the first electrode tab 20, thereby providing a margin for the expansion of the electrode assembly 10 and helping to reduce the risk of damage to the outermost ring of the first electrode 11.

[0114] [Amended according to Rule 26, 29.05.2026] Furthermore, when the electrode assembly 10 expands, the overlapping structure 113 is subjected to lamination pressure along the stacking direction of the first electrode 11, the separator 13, and the second electrode 12, which may inhibit the extension of the overlapping structure 113, posing a risk that the overlapping structure 113 may be difficult to open or fully extend. In the embodiment described above with the first fold 1131 and the second fold 1132, only at least one of the first fold 1131 and the second fold 1132 needs to be fully extended or partially opened, which helps to reduce the risk of damage to the outermost ring of the first electrode 11 and improves the reliability of the overlapping structure 113.

[0115] [Amended according to Rule 26 29.05.2026] In some embodiments, referring to Figures 4 and 6, along the first direction Y, the projections of the fourth segment 113d, the fifth segment 113e, and the sixth segment 113f overlap.

[0116] [Amended according to Rule 26 29.05.2026] In some embodiments, referring to Figures 4 and 6, along the first direction Y, the distance between the first segment 113a and the winding center of the electrode assembly 10 is greater than the distance between the third segment 113c and the winding center of the electrode assembly 10.

[0117] [Revised according to Rule 26, 29.05.2026] In other embodiments, please refer to FIG7, along the first direction Y, the distance between the first segment 113a and the winding center of the electrode assembly 10 is less than the distance between the third segment 113c and the winding center of the electrode assembly 10.

[0118] [Amended according to Rule 26 29.05.2026] In some embodiments, referring to Figures 4 and 6, along the first direction Y, the distance between the fourth segment 113d and the winding center of the electrode assembly 10 is greater than the distance between the sixth segment 113f and the winding center of the electrode assembly 10.

[0119] [Revised according to Rule 26, 29.05.2026] In other embodiments, please refer to FIG7, along the first direction Y, the distance between the fourth segment 113d and the winding center of the electrode assembly 10 is less than the distance between the sixth segment 113f and the winding center of the electrode assembly 10.

[0120] [Revised according to Rule 26, 29.05.2026] In some embodiments, please refer to Figures 4 to 7. The stacking direction of the first segment 113a, the second segment 113b and the third segment 113c is the same as the stacking direction of the fourth segment 113d, the fifth segment 113e and the sixth segment 113f. The sixth segment 113f is connected to the third segment 113c, so that the folding directions of the first folded portion 1131 and the second folded portion 1132 are opposite. The first folded portion 1131 and the second folded portion 1132 with this shape can be formed by pressing out the protrusion of the first electrode 11 and then flattening the protrusion, which is beneficial to the forming of the first folded portion 1131 and the second folded portion 1132.

[0121] [Revised according to Rule 26, 29.05.2026] In some embodiments, referring to FIG6, along the winding direction X of the electrode assembly 10, the distance between the bend of the second segment 113b relative to the first segment 113a and the bend of the third segment 113c relative to the second segment 113b is L1, and the distance between the bend of the fifth segment 113e relative to the fourth segment 113d and the bend of the fifth segment 113e relative to the sixth segment 113f is L2, satisfying L2 > L1.

[0122] [Revised according to Rule 26, 29.05.2026] The distance between the second fold 1132 and the first tab 20 is closer than the distance between the first fold 1131 and the first tab 20. In the event of a drop of the secondary battery 100, the electrode assembly 10 is subjected to instantaneous impact. When the condition L2 > L1 is met, the opened second fold 1132 is more conducive to dispersing the stress at the connection between the first electrode 11 and the first tab 20.

[0123] [Amended according to Rule 26, 29.05.2026] As an example, L2 can be any one of 1.1L, 1.15L, 1.2L, 1.25L1, 1.3L1, 1.35L1, 1.4L1, 1.45L1, 1.5L1, 1.55L1, 1.6L1, 1.65L1, 1.7L1, 1.75L1, 1.8L1, 1.85L1, 1.9L1, 1.95L1, 2L1, or any value between the two.

[0124] [Amended according to Rule 26 29.05.2026] In some embodiments, the maximum outer diameter that the electrode assembly 10 can expand to is D1, the minimum outer diameter of the electrode assembly 10 is D2, and along the winding direction X of the electrode assembly 10, the distance between the bend of the second segment 113b relative to the first segment 113a and the bend of the third segment 113c relative to the second segment 113b is L1, and the distance between the bend of the fifth segment 113e relative to the fourth segment 113d and the bend of the fifth segment 113e relative to the sixth segment 113f is L2, satisfying 2(L1+L2)≥π(D1-D2).

[0125] [Revised according to Rule 26 to 29.05.2026] When L1+L2 satisfies the condition L≥π(D1-D2) / 2, it is beneficial to increase the expansion margin of the electrode assembly 10, and to further reduce the force on the connection position of the outermost first electrode 11 when the electrode assembly 10 expands, thereby further reducing the risk of damage to the first electrode 11.

[0126] [Revised according to Rule 26, May 2026] The following uses a cylindrical hard-shell secondary battery 100 as an example to illustrate the measurement method of the maximum outer diameter D1 and the minimum outer diameter D2:

[0127] [Amended according to Rule 26 29.05.2026] Maximum outer diameter D1: When the secondary battery 100 is fully discharged, that is, when the terminal device is disassembled at 0% SOC (State of Charge, the usable state of the remaining charge in the battery), the electrode assembly 10 is obtained and the housing 40 is obtained. The inner diameter of the housing 40 is measured with an optical microscope at an ambient temperature of 25°C. This is the maximum outer diameter D1 that the electrode assembly 10 can expand to.

[0128] [Amended according to Rule 26, 29.05.2026] Minimum outer diameter D2: The minimum outer diameter D2 is obtained by measuring the outer diameter of the wound electrode assembly 10 with an optical microscope at an ambient temperature of 25°C.

[0129] [Revised according to Rule 26, 29.05.2026] When the electrode assembly 10 of the secondary battery 100 is of other shapes, the detection method for the electrode assembly 10 described above can be used for detection, and will not be repeated here.

[0130] [Amended according to Rule 26, 29.05.2026] In some embodiments, the overlapping structure 113 includes a first fold 1131 and a second fold 1132, satisfying 0.1mm≤L1.

[0131] [According to Rule 26, amended 29.05.2026] When L1 satisfies the condition 0.1mm≤L1, it is beneficial to reduce the stress on the connection position of the outermost first electrode 11 when the electrode assembly 10 expands, thereby reducing the risk of damage to the first electrode 11.

[0132] [Amended according to Rule 26, 29.05.2026] As an example, L1 can be one of 0.1mm, 0.2mm, 0.3mm, 0.41mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2mm, or any value between the two.

[0133] [Amended according to Rule 26, 29.05.2026] In some embodiments, the overlapping structure 113 includes a first fold 1131 and a second fold 1132, satisfying 0.1mm≤L2.

[0134] [According to Rule 26, amended 29.05.2026] When L2 satisfies the condition 0.1mm≤L2, it is beneficial to reduce the stress on the connection position of the outermost first electrode 11 when the electrode assembly 10 expands, thereby reducing the risk of damage to the first electrode 11.

[0135] [Amended according to Rule 26, 29.05.2026] As an example, L2 can be one of 0.1mm, 0.2mm, 0.3mm, 0.41mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2mm, or any value between the two.

[0136] [Amended according to Rule 26, 29.05.2026] In some embodiments, 0.2mm≤L1+L2 is satisfied. When L1+L2 satisfies the condition 0.2mm≤L1+L2, it is beneficial to reduce the stress on the connection position of the outermost first electrode 11 when the electrode assembly 10 expands, thereby reducing the risk of damage to the first electrode 11.

[0137] [According to Rule 26, amended 29.05.2026] In some embodiments, L1+L2≤3mm is satisfied, so that the portion reserved by the first electrode 11 for the electrode assembly 10 to be stretched during expansion is not too long, which is beneficial to reducing the space occupied by the overlapping structure 113 and also beneficial to the processing and forming of the overlapping structure 113.

[0138] [Amended according to Rule 26, 29.05.2026] In some embodiments, when there is only a first fold 1131 and no other folds, the length of the first fold 1131 is between 0.2mm and 3mm. Or when there is only a second fold 1132 and no other folds, the length of the second fold 1132 is between 0.2mm and 3mm. This helps to reduce the stress on the connection position of the outermost first electrode 11 when the electrode assembly 10 expands, thereby reducing the risk of damage to the first electrode 11. Furthermore, it prevents the portion of the first electrode 11 reserved for stretching during the expansion of the electrode assembly 10 from becoming too long, which helps to reduce the space occupied by the overlapping structure 113 and also facilitates the processing and forming of the overlapping structure 113.

[0139] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to Figures 4 and 5, along the winding direction X of the electrode assembly 10, the outermost ring of the electrode assembly 10 includes a second electrode 12, the outermost ring of the second electrode 12 includes a second empty foil region 121b, and the second tab 30 is connected to the second empty foil region 121b of the outermost ring of the second electrode 12. Along the winding direction X of the electrode assembly 10, the projection of the overlapping structure 113 is located between the projection of the first tab 20 and the projection of the second tab 30, and the projection direction of the overlapping structure 113, the projection direction of the first tab 20 and the projection direction of the second tab 30 are the stacking directions of the first electrode 11, the separator 13 and the second electrode 12.

[0140] [Amended according to Rule 26, 29.05.2026] In the winding structure of the electrode assembly 10, the diameters of the first tab 20 and the second tab 30 are relatively large. During the expansion of the electrode assembly 10, the first tab 20 and the second tab 30 first abut against the housing 40, resulting in a large interlayer compressive force at the first tab 20 and the second tab 30. When the projection of the overlapping structure 113 is located between the projections of the first tab 20 and the second tab 30, it is beneficial to increase the initial contact area between the electrode assembly 10 and the housing 40, reducing the risk of internal collapse of the winding structure of the electrode assembly 10 due to local stress concentration between the electrode assembly 10 and the housing 40. This is beneficial to improving the interface performance of the electrode assembly 10 and reducing the risk of cycle degradation of the secondary battery 100. In some embodiments, referring to FIG5, along the winding direction of the electrode assembly 10, the length of the overlapping structure 113 is L, and the minimum distance between the first tab 20 and the second tab 30 is T, satisfying 0.04T≤L≤T.

[0141] [Amended according to Rule 26, 29.05.2026] In the winding structure of the electrode assembly 10, the diameters of the first tab 20 and the second tab 30 are relatively large. During the expansion of the electrode assembly 10, the first tab 20 and the second tab 30 first come into contact with the shell 40, resulting in a large interlayer compressive force at the first tab 20 and the second tab 30. When 0.04T≤L≤T is satisfied, on the one hand, the overall length of the overlapping structure 113 is not too small, which helps to increase the contact area between the electrode assembly 10 and the shell 40, reducing the risk of internal collapse of the winding structure of the electrode assembly 10 due to local stress concentration between the electrode assembly 10 and the shell 40. This helps to improve the interface performance of the electrode assembly 10 and reduce the risk of cycle degradation of the secondary battery 100. On the other hand, ensuring that the overall length of the overlapping structure 113 is not too large helps to reduce the risk of overlap between the overlapping structure 113 and the second tab 30 along the stacking direction of the first electrode 11, the separator 13 and the second electrode 12. This helps to reduce the risk that the overlapping structure 113 will be squeezed and difficult to spread out or unfold. At the same time, it also helps to reduce the influence of the interface between the first electrode 11 and the second electrode 12 and electrolyte wetting, and reduce the possibility of deterioration of the cycle performance of the secondary battery 100.

[0142] [Amended according to Rule 26, May 2026] It should be noted that, along the winding direction of the electrode assembly 10, the length L of the overlapping structure 113 is ≥ L1 + L2. When the third segment 113c and the sixth segment 113f are directly connected, L = L1 + L2. When the third segment 113c and the sixth segment 113f are indirectly connected, L > L1 + L2. For example, a connecting segment is provided between the third segment 113c and the sixth segment 113f, connecting the third segment 113c and the sixth segment 113f.

[0143] [Amended according to Rule 26, 29.05.2026] As an example, L can be one of 0.05T, 0.1T, 0.15T, 0.2T, 0.25T, 0.3, 0.35T, 0.4T, 0.45T, 0.5T, 0.55T, 0.6T, 0.65T, 0.7T, 0.75T, 0.8T, 0.85T, 0.9T, 0.95T or T, or any value between the two.

[0144] [Amended according to Rule 26, 29.05.2026] In some embodiments, along the winding direction X of the electrode assembly 10, the minimum distance between the fourth segment 113d and the first tab 20 is between 1 and 10 mm, so that the distance between the connection point of the first electrode 11 and the first tab 20 and the fourth segment 113d is not too far, which helps to reduce the stress at the connection point of the first electrode 11 and the first tab 20, thereby further reducing the risk of damage to the outermost ring of the first electrode 11; it also ensures that the distance between the connection point of the first electrode 11 and the first tab 20 and the fourth segment 113d is not too close, which helps to provide space for the formation of the overlapping structure 113, and helps to reduce the risk of interference between the overlapping structure 113 and the tab.

[0145] [Amended according to Rule 26 29.05.2026] As an example, the minimum distance between the fourth segment 113d and the first tab 20 can be one of 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, or any value between the two.

[0146] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to FIG8, the first electrode 11 further includes a seventh segment 114 and an eighth segment 116, which are sequentially connected along the winding direction X of the electrode assembly 10. The secondary battery 100 also includes a first adhesive 50, which is bonded to both the seventh segment 114 and the eighth segment 116, and is also bonded to the overlapping structure 113.

[0147] [Amended according to Rule 26, May 2026] The first adhesive 50 is bonded to the seventh segment 114, the eighth segment 116, and the overlapping structure 113, which helps maintain the morphology of the overlapping structure 113. When manufacturing the secondary battery 100, the first electrode 11 can be folded first to form the overlapping structure 113, and then the first electrode 11, the separator 13, and the second electrode 12 can be wound to form a wound structure. The first adhesive 50 plays a role in fixing the morphology of the overlapping structure 113, which helps reduce the risk of the overlapping structure 113 spreading out or partially spreading out during the winding process. In addition, in the event of an accident such as an impact on the electrode assembly 10, the overlapping structure 113 may be squeezed or impacted. The first adhesive 50 helps maintain the morphology of the overlapping structure 113, which helps reduce the risk of the overlapping structure 113 spreading out or partially spreading out before the electrode assembly 10 expands.

[0148] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to Figures 4 and 8, the secondary battery 100 further includes a second adhesive 60, with the first adhesive 50 bonded to one side of the first electrode 11 along the thickness direction of the first electrode 11, and the second adhesive 60 bonded to the other side of the first electrode 11. The second adhesive 60 is bonded to both the seventh segment 114 and the eighth segment 116, and also to the overlapping structure 113. The second adhesive helps maintain the morphology of the overlapping structure 113, reduces the risk of the overlapping structure 113 unraveling or partially unraveling during winding, and also reduces the risk of the overlapping structure 113 unraveling or partially unraveling before the electrode assembly 10 expands.

[0149] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to Figures 4 and 8, the first adhesive member 50 is also bonded to the first tab 20. The first adhesive member 50 serves to fix the first tab 20, which helps to reduce the risk of the first tab 20 detaching from or partially detaching from the first electrode 11, reduces the risk of damage to the first electrode 11, and also reduces the possibility of the first tab 20 piercing the diaphragm and coming into contact with an electrode of different polarity. In addition, bonding the first adhesive member 50 together with the first tab 20 and the overlapping structure 113 helps to save on adhesive processes.

[0150] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to Figures 4 and 8, the second adhesive 60 is also bonded to the first tab 20. The second adhesive 60 serves to fix the first tab 20, which helps to reduce the risk of the first tab 20 detaching from or partially detaching from the first electrode 11, reduces the risk of damage to the first electrode 11, and also reduces the possibility of the first tab 20 piercing the diaphragm and coming into contact with an electrode of different polarity. In addition, bonding the first adhesive 50 together with the first tab 20 and the overlapping structure 113 helps to save on adhesive processes.

[0151] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to FIG9, along the width direction Z of the first electrode 11, the first tab 20 is connected to the first electrode 11 and extends beyond the first electrode 11. Along the direction in which the first tab 20 extends, the first adhesive member 50 extends beyond the first electrode 11.

[0152] [Amended according to Rule 26, 29.05.2026] In extreme cases, the overlapping structure 113 may crack or break. Sharp cracks and burrs at the cracks can easily puncture the separator, causing contact between electrodes of different polarities and resulting in a short circuit. Along the direction in which the first tab 20 extends, the first adhesive 50 extends beyond the first electrode 11, which helps reduce the possibility of the separator being punctured at the overlapping structure 113 and causing a short circuit, thus improving the safety of the secondary battery 100.

[0153] [Amended according to Rule 26 29.05.2026] In an embodiment where the first adhesive 50 is also bonded to the first tab 20, the first adhesive 50 extends beyond the first electrode 11 along the direction in which the first tab 20 extends. This helps to reduce the possibility of short circuits caused by burrs on the first tab 20 puncturing the separator, thereby improving the safety of the secondary battery 100.

[0154] [Revised according to Rule 26, 29.05.2026] In some embodiments, please refer to FIG10, the first adhesive 50 extends beyond the first electrode 11 in the direction opposite to the direction in which the first tab 20 extends, which helps to reduce the possibility of the separator at the overlapping structure 113 being punctured and short-circuited, and helps to improve the safety of the secondary battery 100.

[0155] [Amended according to Rule 26, 29.05.2026] In some embodiments, referring to FIG11, along the width direction Z of the first electrode 11, the first tab 20 is connected to the first electrode 11 and extends beyond the first electrode 11. Along the direction in which the first tab 20 extends, the second adhesive 60 extends beyond the first electrode 11, which helps to reduce the possibility of the separator corresponding to the overlapping structure 113 being punctured and short-circuited, and helps to improve the safety of the secondary battery 100.

[0156] [According to Rule 26, amended 29.05.2026] In an embodiment where the second adhesive 60 is also bonded to the first tab 20, the second adhesive 60 extends beyond the first electrode 11 along the direction in which the first tab 20 extends. This helps to reduce the possibility of short circuits caused by burrs on the first tab 20 puncturing the separator, thereby improving the safety of the secondary battery 100.

[0157] [Revised according to Rule 26, 29.05.2026] In some embodiments, please refer to FIG12, the second adhesive 60 extends beyond the first electrode 11 in the direction opposite to the direction in which the first tab 20 extends. This helps to reduce the possibility of the separator corresponding to the overlapping structure 113 being punctured and short-circuited, and helps to improve the safety of the secondary battery 100.

[0158] [Amended according to Rule 26, 29.05.2026] In some embodiments, the peel strength between the first adhesive 50 and the seventh segment 114 is F1, which satisfies 0 N / mm ≤ F1 ≤ 0.08 N / mm.

[0159] [Amended according to Rule 26, 29.05.2026] It should be noted that the first adhesive 50 will experience a decrease in peel strength between the first adhesive 50 and the seventh segment 114 after contact with the electrolyte. Here, F1 refers to the presence of electrolyte within the housing 40, and the peel strength between the first adhesive 50 and the seventh segment 114 after immersion in the electrolyte.

[0160] [Revised according to Rule 26, 29.05.2026] When F1 = 0, the peel strength between the first adhesive 50 and the seventh segment 114 before immersion in electrolyte is greater than 0, which helps to reduce the risk of the overlapping structure 113 unraveling or partially unraveling during the winding process.

[0161] [Revised according to Rule 26, 29.05.2026] When F1 satisfies the condition 0 N / mm < F1 ≤ 0.08 N / mm, on the one hand, the peel strength F1 between the first adhesive 50 and the seventh segment 114 is not too large, which is conducive to the smooth peeling of the first adhesive 50 and the seventh segment 114 when the electrode assembly 10 expands, reducing the risk that the first adhesive 50 will affect the effect of the overlapping structure 113 when the electrode assembly 10 expands; on the other hand, the peel strength F1 between the first adhesive 50 and the seventh segment 114 is not too small, which is conducive to reducing the risk that the overlapping structure 113 will fall apart or partially fall apart when the electrode assembly 10 is subjected to impact, etc., which is conducive to improving the reliability of the overlapping structure 113.

[0162] [Amended according to Rule 26 29.05.2026] As an example, F1 can be any one of 0 N / mm, 0.01 N / mm, 0.02 N / mm, 0.03 N / mm, 0.04 N / mm, 0.05 N / mm, 0.06 N / mm, 0.07 N / mm or 0.08 N / mm.

[0163] [Amended according to Rule 26, dated May 2026] This application uses a high-speed rail tensile testing machine to test the peel strength between the first bond 50 and the seventh bond 114, according to GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tapes". The test procedure is as follows:

[0164] [Amended according to Rule 26, dated May 2026] Discharge the secondary battery 100 to 3.0V, then disassemble the secondary battery 100. Remove the first electrode 11 and the first adhesive component 50 bonded to it as a whole, and wipe the electrolyte off the surface with lint-free paper. Then cut the first adhesive component 50 and the seventh segment 114 into strip-shaped samples. Along the length of the sample, adhere the side of the sample with the first electrode 11 to the steel plate using double-sided adhesive (Nitto 5000NS), with an adhesion length of not less than 10mm. The steel plate is fixed in the corresponding position of the high-speed rail tensile testing machine. One end of the seventh segment 114 on the other side of the sample is pulled up and the sample is placed in the clamp and clamped. The angle between the pulled-up sample and the steel plate in space is 180°. The clamp pulls the sample at a speed of 5±0.2mm / s. The average tensile force in the stable area is finally measured and recorded as the peel strength between the first adhesive 50 and the seventh segment 114, denoted as F1, with the unit being N / m.

[0165] [Amended according to Rule 26, 29.05.2026] In some embodiments, an electrolyte is also provided inside the housing 40. The peel strength between the first adhesive 50 and the overlapping structure 113 is F2, which satisfies 0 N / mm ≤ F2 ≤ 0.08 N / mm.

[0166] [Amended according to Rule 26 29.05.2026] Wherein, F2 is the peel strength between the second adhesive 60 and the overlapping structure 113 after being soaked in electrolyte.

[0167] [According to Rule 26, amended 29.05.2026] When F2 = 0, the peel strength between the second adhesive 60 and the overlapping structure 113 before being soaked in the electrolyte is greater than 0, which helps to reduce the risk of the overlapping structure 113 unraveling or partially unraveling during the winding process.

[0168] [Revised according to Rule 26, 29.05.2026] When F2 satisfies the condition 0 N / mm < F2 ≤ 0.08 N / mm, on the one hand, the peel strength F2 between the second adhesive 60 and the overlapping structure 113 is not too large, which is conducive to the smooth peeling of the second adhesive 60 and the overlapping structure 113 when the electrode assembly 10 expands, reducing the risk that the second adhesive 60 will affect the effect of the overlapping structure 113 when the electrode assembly 10 expands; on the other hand, the peel strength F2 between the second adhesive 60 and the overlapping structure 113 is not too small, which is conducive to reducing the risk that the overlapping structure 113 will fall apart or partially fall apart when the electrode assembly 10 is subjected to impact, etc., which is conducive to improving the reliability of the overlapping structure 113.

[0169] [Amended according to Rule 26 29.05.2026] As an example, F2 can be any one of 0 N / mm, 0.01 N / mm, 0.02 N / mm, 0.03 N / mm, 0.04 N / mm, 0.05 N / mm, 0.06 N / mm, 0.07 N / mm or 0.08 N / mm.

[0170] [Amended according to Rule 26 29.05.2026] The test for F2 can refer to the peel strength F1 between the first adhesive 50 and the seventh segment 114 after being soaked in electrolyte, and will not be repeated here.

[0171] [Amended according to Rule 26, 29.05.2026] In some embodiments, an electrolyte is also provided inside the housing 40. The peel strength between the first adhesive 50 and the eighth segment 116 is F3.

[0172] [Amended according to Rule 26 29.05.2026] Wherein, F3 is the peel strength between the first adhesive 50 and the eighth segment 116 after being soaked in electrolyte.

[0173] [Revised according to Rule 26, 29.05.2026] When F3 = 0, the peel strength between the first adhesive 50 and the eighth segment 116 before immersion in electrolyte is greater than 0, which helps to reduce the risk of the overlapping structure 113 unraveling or partially unraveling during the winding process.

[0174] [Revised according to Rule 26, 29.05.2026] When F3 satisfies the condition 0 N / mm < F2 ≤ 0.08 N / mm, on the one hand, the peel strength F3 between the first adhesive 50 and the eighth segment 116 is not too large, which is conducive to the smooth peeling of the first adhesive 50 and the eighth segment 116 when the electrode assembly 10 expands, reducing the risk that the first adhesive 50 will affect the effect of the overlapping structure 113 when the electrode assembly 10 expands; on the other hand, the peel strength F3 between the first adhesive 50 and the eighth segment 116 is not too small, which is conducive to reducing the risk that the overlapping structure 113 will fall apart or partially fall apart when the electrode assembly 10 is subjected to impact, etc., which is conducive to improving the reliability of the overlapping structure 113.

[0175] [Amended according to Rule 26 29.05.2026] As an example, F3 can be any one of 0 N / mm, 0.01 N / mm, 0.02 N / mm, 0.03 N / mm, 0.04 N / mm, 0.05 N / mm, 0.06 N / mm, 0.07 N / mm or 0.08 N / mm.

[0176] [Amended according to Rule 26, 29.05.2026] The test for F3 can refer to the peel strength F1 between the first adhesive 50 and the seventh segment 114 after being soaked in electrolyte, and will not be repeated here.

[0177] [Amended according to Rule 26, 29.05.2026] In some embodiments, the first adhesive 50 includes a substrate layer (not shown) and an adhesive (not shown) disposed on the substrate layer. The substrate layer may be selected from polyethylene terephthalate, co-extruded polypropylene, oriented polystyrene, thermoplastic polyurethane, polylactic acid, and polyolefin. The adhesive is selected from one or a combination of acrylic resin, polypropylene, or rubber. By selecting different types and / or qualities of materials to adjust the adhesive strength, the peel strength between the first adhesive 50 and the seventh segment 114, the peel strength between the first adhesive 50 and the overlapping structure 113, and the peel strength between the first adhesive 50 and the eighth segment 116 can be adjusted.

[0178] [Amended according to Rule 26, May 2026] It should be noted that the peel strength between the first adhesive component 50 and the seventh segment 114 before immersion in the electrolyte affects the peel strength F1 between the first adhesive component 50 and the seventh segment 114 after immersion in the electrolyte. Therefore, by selecting different types and / or qualities of materials to adjust the adhesive strength, F1 can be adjusted. The principles and methods for adjusting F2 and F3, as well as the principles and methods for adjusting the peel strength between the second adhesive component 60 and the seventh segment 114, the overlapping structure 113, and the eighth segment 116 after immersion in the electrolyte, can refer to the adjustment of F1, and will not be repeated here.

[0179] [Revised according to Rule 26, 29.05.2026] In some embodiments, please refer to FIG13, along the winding direction X of the electrode assembly 10, the length of the first adhesive 50 is S1, which satisfies 2mm≤S1≤20mm.

[0180] [Revised according to Rule 26, 29.05.2026] When the length S1 of the first adhesive 50 satisfies the condition 2mm≤S1≤20mm, on the one hand, the area of ​​the first adhesive 50 is not too small, which is conducive to improving the bonding strength between the first adhesive 50 and the seventh segment 114, the overlapping structure 113 and the eighth segment 116, reducing the risk of the overlapping structure 113 coming apart during the winding process or when it is impacted, which is conducive to improving the reliability of the overlapping structure 113; on the other hand, the area of ​​the first adhesive 50 is not too large, which is conducive to the smooth peeling of the first adhesive 50 from the seventh segment 114, the overlapping structure 113 and the eighth segment 116 when the electrode assembly 10 expands, reducing the risk that the first adhesive 50 will affect the effect of the overlapping structure 113 when the electrode assembly 10 expands.

[0181] [Amended according to Rule 26 29.05.2026] As an example, S1 can be one of 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm or 20mm, or any value between the two.

[0182] [Modified according to Rule 26, 29.05.2026] In some embodiments, please refer to FIG14. Along the winding direction X of the electrode assembly 10, the length of the second adhesive 60 is S2, which satisfies 2mm≤S2≤20mm. On the one hand, this prevents the area of ​​the second adhesive 60 from being too small, which is beneficial to improving the bonding strength between the second adhesive 60 and the seventh segment 114, the eighth segment 116 and the overlapping structure 113, reducing the risk of the overlapping structure 113 coming apart during the winding process or when subjected to impact, and thus improving the reliability of the overlapping structure 113. On the other hand, this prevents the area of ​​the second adhesive 60 from being too large, which is beneficial to allowing the second adhesive 60 to peel off smoothly from the seventh segment 114, the eighth segment 116 and the overlapping structure 113 when the electrode assembly 10 expands, reducing the risk that the second adhesive 60 will affect the effect of the overlapping structure 113 when the electrode assembly 10 expands.

[0183] [Amended according to Rule 26 29.05.2026] As an example, S2 can be one of 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm or 20mm, or any value between the two.

[0184] [Revised according to Rule 26, 29.05.2026] In some embodiments, 6mm≤S1≤13mm is satisfied. On the one hand, this prevents the area of ​​the first adhesive 50 from being too small, which is beneficial to improving the bonding strength between the first adhesive 50 and the seventh segment 114, the overlapping structure 113 and the eighth segment 116, and further reduces the risk of the overlapping structure 113 coming apart during the winding process or when subjected to impact, thus improving the reliability of the overlapping structure 113. On the other hand, this prevents the area of ​​the first adhesive 50 from being too large, which is beneficial to allowing the first adhesive 50 to peel off smoothly from the seventh segment 114, the overlapping structure 113 and the eighth segment 116 when the electrode assembly 10 expands, and further reduces the risk that the first adhesive 50 will affect the effect of the overlapping structure 113 when the electrode assembly 10 expands.

[0185] [Amended according to Rule 26, 29.05.2026] In some embodiments, 6mm≤S2≤13mm is satisfied. On the one hand, this prevents the area of ​​the second adhesive 60 from being too small, which is beneficial to improving the bonding strength between the second adhesive 60 and the seventh segment 114, the eighth segment 116 and the overlapping structure 113, and further reduces the risk of the overlapping structure 113 coming apart during the winding process or when subjected to impact, thus improving the reliability of the overlapping structure 113. On the other hand, this prevents the area of ​​the second adhesive 60 from being too large, which is beneficial to allowing the second adhesive 60 to peel off smoothly from the seventh segment 114, the eighth segment 116 and the overlapping structure 113 when the electrode assembly 10 expands, and further reduces the risk that the second adhesive 60 will affect the effect of the overlapping structure 113 when the electrode assembly 10 expands.

[0186] [Amended according to Rule 26 29.05.2026] In some embodiments, the material of the first adhesive 50 includes at least one of acrylic resin, polypropylene, or rubber.

[0187] [Amended according to Rule 26 29.05.2026] In some embodiments, the material of the second adhesive 60 includes at least one of acrylic resin, polypropylene, or rubber.

[0188] [Amended according to Rule 26, May 2026] To verify the impact of the overlapping structure 113 and the first adhesive 50 on whether the first electrode 11 is damaged, the following test was conducted:

[0189] [Amended to 29.05.2026 according to Rule 26] Conduct a battery cycle test on the secondary battery 100: Place the secondary battery 100 in a 55°C environment and let it stand for 30 minutes, then charge and discharge it according to the following steps: Charge at a constant current of 2.5C to 4.2V, then charge at a constant voltage to 0.5C; then charge at a constant current of 0.5C to 4.45V, then charge at a constant voltage to 0.02C; let it stand for 5 minutes, then discharge at a constant current of 1C to 3V, and let it stand for 5 minutes. This is one cycle. Repeat the above cycle steps 300 times, then disassemble the secondary battery 100 and observe whether the connection between the first electrode 11 and the first tab 20 is damaged.

[0190] [Amended to Rule 26, dated May 2026] Battery drop test: The secondary battery 100 was pretreated at 25°C and left to stand at room temperature for 60 minutes. The voltage of the secondary battery 100 before the drop test was then tested. The secondary battery 100 was placed in a fixture and dropped freely from a position 2m above the ground using a drop device in the following order: head-tail-right corner of head-right corner of tail-left corner of head-left corner of tail (angle: 45±15°), repeated 10 times. After the drop test, the secondary battery 100 was disassembled, and the connection between the first electrode plate 11 and the first tab 20 was observed to see if it was damaged.

[0191] [Amended according to Rule 26, 29.05.2026] In the two tests described above, 100 secondary batteries 100 were tested for each embodiment or comparative example. Each secondary battery 100 had a diameter of 10.1 mm and a height of 5.25 mm. Along the winding direction of the electrode assembly 10, the minimum distance between the first tab 20 and the second tab 30 was T = 8 mm. If the connection between the first electrode 11 and the first tab 20 was damaged, the test failed; if the connection between the first electrode 11 and the first tab 20 was undamaged, the test passed. Pass rate = (number of passes / 100) × 100%.

[0192] [Amended according to Rule 26, 29.05.2026] The specific implementation of the secondary battery 100 in the embodiments and comparative examples will be described below.

[0193] [Amended according to Rule 26, May 2026] Example 1:

[0194] [Amended according to Rule 26, dated May 2026] A secondary battery 100 is assembled as follows:

[0195] [Amended according to Rule 26, 29.05.2026] (1) Preparation of anode electrode: The anode active materials artificial graphite, conductive carbon black (Super P), and styrene-butadiene rubber (SBR) are mixed in a weight ratio of 96:1.5:2.5, and deionized water is added as a solvent to prepare a slurry with a weight percentage of 70wt%, and stirred evenly. The slurry is uniformly coated on one surface of a copper foil with a thickness of 10μm for the anode current collector, leaving a blank foil area at the edge of the copper foil. It is dried at 110°C to obtain an anode electrode with a coating thickness of 150μm on one side partially coated with an anode active material layer. The above steps are repeated on the other surface of the anode electrode to obtain an anode electrode with a coated area and a blank foil area. An anode tab is welded to the blank foil area at one end of the anode electrode.

[0196] [Amended according to Rule 26, 29.05.2026] (2) Preparation of cathode electrode: Lithium cobalt oxide (LiCoO2), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 97.5:1.0:1.5. N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75wt%, and the mixture is stirred evenly. The slurry is uniformly coated on one surface of a cathode current collector aluminum foil with a thickness of 12μm, leaving a blank foil area in the aluminum foil. Then it is dried at 90°C to obtain a cathode electrode with a cathode active material layer thickness of 100μm. The above coating steps are repeated on the other surface of the aluminum foil to obtain a cathode electrode. Cathode tabs are welded to the blank foil area of ​​the cathode electrode.

[0197] [Amended according to Rule 26 29.05.2026] (3) Preparation of electrolyte: In a dry argon atmosphere, ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) are first mixed in a mass ratio of EC:EMC:DEC = 30:50:20 to form a basic organic solvent. Then, lithium salt lithium hexafluorophosphate (LiPF6) is added to the basic organic solvent to dissolve and mix evenly to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0198] [Amended according to Rule 26 29.05.2026] (4) Preparation of the separator 13: The separator 13 adopts a three-layer structure, which includes a first adhesive layer, a first substrate layer and a first adhesive layer stacked together. The first substrate layer is made of polyethylene (PE), the first adhesive layer contains a first adhesive, and the first adhesive layer also contains boehmite.

[0199] [Amended according to Rule 26 29.05.2026] (5) Manufacturing the overlapping structure 113: A round bar is used to press the anode electrode sheet in the unfolded state to form an arc-shaped protrusion. Along the winding direction X of the electrode assembly 10, the arc-shaped protrusion is located on the side of the anode tab near the winding center. The arc-shaped protrusion on the anode electrode sheet is flattened to form the overlapping structure 113. The first adhesive 50 is used to bond the seventh segment 114, the second region 115 and the eighth segment 116 of the first electrode sheet 11. The second adhesive 60 is used to bond the seventh segment 114, the second region 115 and the eighth segment 116 on the other side of the thickness direction of the first electrode sheet 11. After the electrode assembly 10 is immersed in the electrolyte, the peel strength between the second adhesive 60 and the seventh segment 114 is F4, the peel strength between the second adhesive 60 and the overlapping structure 113 is F5, and the peel strength between the second adhesive 60 and the eighth segment 116 is F6. The substrate layer of the first adhesive 50 and the second adhesive 60 is polyethylene terephthalate with a thickness of 12 μm, and the adhesive is acrylic resin with a thickness of 4 μm.

[0200] [Revised according to Rule 26, 29.05.2026] (6) Preparation of electrode assembly 10: The cathode electrode, the separator 13 and the anode electrode are stacked, the structure obtained after stacking is wound, and the outermost electrode of the wound structure is the anode electrode located on the electrode, and the anode tab is connected to the outermost anode electrode.

[0201] [Amended according to Rule 26, 29.05.2026] (7) Assembly of electrode assembly 10: Place the punched aluminum-plastic film in the assembly fixture with the punched surface facing up, place the electrode assembly 10 in the punch, and apply external force to press it. Then cover the electrode assembly 10 with another punched aluminum-plastic film with the punched surface facing down, and heat seal the two aluminum-plastic films around their perimeter by hot pressing to obtain the assembled electrode assembly 10.

[0202] [Revised according to Rule 26, 29.05.2026] (8) Electrolyte injection and encapsulation: Electrolyte is injected into the cylindrical shell through the injection hole. After encapsulation, settling, formation and other processes, a secondary battery 100 is obtained. The secondary battery 100 has a diameter of 10.1 mm and a height of 5.25 mm. Along the winding direction of the electrode assembly 10, the minimum distance between the first tab 20 and the second tab 30 is T = 8 mm.

[0203] [Revised according to Rule 26, 29.05.2026] Comparative Example 1: The difference from the Example is that Comparative Example 1 does not perform step (5) of Example 1, and the remaining steps are the same as those of Example 1.

[0204] [Revised according to Rule 26, 29.05.2026] Comparative Example 2: The difference from Example 7 is that, in Comparative Example 2, along the winding direction X of the electrode assembly 10, the overlapping structure 113 is located on the side of the first tab 20 away from the winding center of the electrode assembly 10, and the remaining steps are the same as in Example 7.

[0205] [Revised according to Rule 26, 29.05.2026] Examples 2-25: The only difference from Example 1 is the parameters shown in Table 1; all other parameters remain the same.

[0206] [Revised according to Rule 26, 29.05.2026] Example 26: The difference from Example 7 is that in step (5) of Example 26, the first adhesive 50 and the second adhesive 60 are not provided.

[0207] [Amended to Article 26 of Detailed Rules 29.05.2026] The main parameter controls and test results of each embodiment and comparative example are shown in Tables 1 and 2:

[0208] [Revised according to Detailed Rules 26, May 29, 2026] Table 1

[0209] [Corrected according to Rule 26, 29.05.2026] As shown in Table 1 above, compared to Comparative Examples 1-2, Embodiments 1-25 have an overlapping structure 113. Along the winding direction X of the electrode assembly 10, the overlapping structure 113 is located on the side of the first tab 20 near the winding center of the electrode assembly 10. This helps reduce the stress at the connection between the first electrode 11 and the first tab 20, thus providing a margin for expansion of the electrode assembly 10 and reducing the risk of damage to the outermost ring of the first electrode 11. Furthermore, the overlapping structure 113 also acts as a buffer at the connection between the first electrode 11 and the first tab 20 in the event of a drop of the secondary battery 100, further reducing the risk of damage to the outermost ring of the first electrode 11.

[0210] [Revised according to Rule 26, 29.05.2026] As can be seen from Table 1 above, compared with Example 1, Examples 2-8 satisfy 0.2mm≤L1+L2, which is beneficial to reduce the force on the connection position of the outermost first electrode 11 when the electrode assembly 10 expands, thereby reducing the risk of damage to the first electrode 11.

[0211] [Corrected according to Rule 26, 29.05.2026] As shown in Table 1 above, compared with Example 18, the peel strength between the first adhesive 50 and the seventh segment 114 after being soaked in the electrolyte in Examples 7 and 10-17 satisfies 0 N / mm ≤ F1 ≤ 0.08 N / mm, the peel strength between the first adhesive 50 and the overlapping structure 113 after being soaked in the electrolyte satisfies 0 N / mm ≤ F2 ≤ 0.08 N / mm, and the peel strength between the first adhesive 50 and the eighth segment 116 after being soaked in the electrolyte satisfies 0 N / mm ≤ F3 ≤ 0.08 N / mm. Furthermore, F4, F5, and F6 are all between 0 N / mm and 0.08 N / mm, which is beneficial for the first adhesive 50 to peel off smoothly when the electrode assembly 10 expands, reducing the risk that the first adhesive 50 will affect the effect of the folded part when the electrode assembly 10 expands, thereby reducing the risk of damage to the outermost first electrode sheet 11.

[0212] [Revised according to Rule 26, 29.05.2026] As can be seen from Table 1 above, compared with Examples 2-8, L2 > L1 in Examples 19-25, which is beneficial to opening the second fold 1132 in the event of a drop of the secondary battery 100, so as to disperse the stress at the connection between the first electrode 11 and the first tab 20, thereby reducing the risk of damage to the first electrode 11 in the event of a drop.

[0213] [Corrected according to Rule 26, 29.05.2026] As can be seen from Table 1 above, compared with Embodiment 26, Embodiment 7 is provided with a first adhesive 50 and a second adhesive 60. The first adhesive 50 and the second adhesive 60 play a role in fixing the morphology of the overlapping structure 113, which helps to reduce the risk of the overlapping structure 113 spreading out or partially spreading out during the winding process, thereby helping to reduce the risk of the first electrode 11 being damaged when the electrode assembly 10 expands.

[0214] [Revised according to Rule 26, 29.05.2026] Examples 27-31: The only difference from Example 1 is the parameters shown in Table 2; all other parameters remain the same.

[0215] [Revised according to Detailed Rules 26, May 2026] Table 2

[0216] [Corrected according to Rule 26, 29.05.2026] As can be seen from Table 1 above, compared with Examples 1 and 31, L1 / T in Examples 27-30 satisfies 0.04-1, that is, 0.04T≤L1≤T. On the one hand, it is beneficial to reduce the risk of internal collapse of the electrode assembly 10, thereby improving the interface performance of the electrode assembly 10 and reducing the risk of cycle degradation of the secondary battery 100. On the other hand, it is beneficial to reduce the risk of the overlapping structure 113 being squeezed and difficult to disperse or unfold, thereby facilitating the unfolding of the overlapping structure 113 in the event of a drop of the secondary battery 100, so as to disperse the stress at the connection between the first electrode 11 and the first tab 20, thereby reducing the risk of damage to the first electrode 11 in the event of a drop.

[0217] [Amended according to Rule 26, 29.05.2026] This application also provides a method for manufacturing the electrode assembly 10 in any of the above embodiments, comprising the following steps:

[0218] [Revised according to Rule 26, 29.05.2026] S1: The first pole piece 11 in the unfolded state is stamped with a round bar to form an arc-shaped protrusion;

[0219] [Revised according to Rule 26, 29.05.2026] S2: Flatten the arc-shaped protrusion on the first electrode 11 to form an overlapping structure 113;

[0220] [Revised according to Rule 26, May 2026] S3: Use adhesive to fix the overlapping structure 113;

[0221] [Revised according to Rule 26, 29.05.2026] S4: The first electrode 11, the second electrode 12 and the separator 13 in the unfolded state are stacked and wound to form a winding structure, and the overlapping structure 113 is located at the outermost ring of the first electrode 11.

[0222] [Amended according to Rule 26, 29.05.2026] In the above-described manufacturing method of electrode assembly 10, when electrode assembly 10 expands, the overlapping structure 113 is first stretched, causing the overlapping structure 113 to gradually unfold. This helps reduce the stress at the connection between the first electrode 11 and the first electrode tab 20, thereby providing a margin for the expansion of electrode assembly 10 and reducing the risk of damage to the outermost ring of the first electrode 11. Furthermore, adhesive fixing of the overlapping structure 113 helps reduce the risk of the overlapping structure 113 scattering or partially scattering during winding or when the electrode assembly 10 is subjected to impact, thus improving the reliability of the overlapping structure 113.

[0223] [Amended according to Rule 26 29.05.2026] In some embodiments, in the step of flattening the arcuate protrusion on the first electrode 11 to form an overlapping structure 113, the overlapping structure 113 is pressed into a structure having a first fold 1131 and a second fold 1132.

[0224] [Amended according to Rule 26, 29.05.2026] Referring to Figure 15, the embodiments of this application also provide an electronic device 1000, which includes the secondary battery 100 in any of the above embodiments. Since the electronic device 1000 adopts the technical solution of the secondary battery 100 in any of the above embodiments, it at least has the beneficial effects brought by the technical solution of the secondary battery 100 in any of the above embodiments, which will not be described in detail here.

[0225] [Amended according to Rule 26, 29.05.2026] In some embodiments, please refer to FIG15, the electronic device 1000 further includes a device body 200, and a secondary battery 100 is mounted on the device body 200.

[0226] [Amended according to Rule 26, 29.05.2026] In some embodiments, the electronic device 1000 may be a mobile phone, tablet computer, e-reader, AR glasses or VR glasses, etc., which will not be listed here.

[0227] [Amended according to Rule 26, 29.05.2026] Furthermore, those skilled in the art should recognize that the above embodiments are merely illustrative of this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the substantive scope of this application fall within the scope of this application.

Claims

1. A secondary battery, characterized in that, include: An electrode assembly, comprising a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, wherein the first electrode, the second electrode, and the separator are stacked and wound to form a wound structure; Along the winding direction of the electrode assembly, the outermost electrode of the electrode assembly is the first electrode, and the outermost part of the first electrode is partially stacked along a first direction to form an overlapping structure. The first direction is the stacking direction of the second electrode and the separator adjacent to the overlapping structure. The first tab is connected to the outermost ring of the first electrode sheet along the winding direction of the electrode assembly, and the overlapping structure is located on the side of the first tab near the winding center of the electrode assembly.

2. The secondary battery according to claim 1, characterized in that, The first electrode includes a first current collector and a first active material layer stacked together. Along the winding direction of the electrode assembly, the first current collector includes a first coated area with the first active material layer and a first empty foil area without the first active material layer. The first tab is connected to the first empty foil area, and a portion of the first empty foil area is folded to form the overlapping structure.

3. The secondary battery according to claim 1 or 2, characterized in that, The overlapping structure includes a first fold; The first folded portion includes a first segment, a second segment, and a third segment connected in sequence. The second segment is bent relative to the first segment, and the third segment is bent relative to the second segment. The first segment, the second segment, and the third segment are stacked in sequence along the first direction. Along the first direction, the projections of the first segment, the second segment, and the third segment overlap.

4. The secondary battery according to claim 3, characterized in that, The overlapping structure further includes a second fold, which is located between the first fold and the first tab along the winding direction of the electrode assembly. The second fold includes a fourth segment, a fifth segment, and a sixth segment connected in sequence. The fifth segment is bent relative to the fourth segment, and the sixth segment is bent relative to the fifth segment. The fourth segment, the fifth segment, and the sixth segment are stacked in sequence along the first direction. Along the first direction, the projections of the fourth segment, the fifth segment, and the sixth segment overlap.

5. The secondary battery according to claim 4, characterized in that, The stacking direction of the first segment, the second segment, and the third segment is the same as that of the fourth segment, the fifth segment, and the sixth segment; the sixth segment is connected to the third segment.

6. [Amended according to Rule 26, 29.05.2026] The secondary battery according to claim 5 is characterized in that, Along the winding direction of the electrode assembly, the distance between the bend of the second segment relative to the first segment and the bend of the third segment relative to the second segment is L1, and the distance between the bend of the fifth segment relative to the fourth segment and the bend of the fifth segment relative to the sixth segment is L2, satisfying L2 > L1.

7. [Amended according to Rule 26, 29.05.2026] The secondary battery according to claim 5 is characterized in that, The minimum distance between the bend of the second segment relative to the first segment and the bend of the third segment relative to the second segment is L1, and the minimum distance between the bend of the fifth segment relative to the fourth segment and the bend of the fifth segment relative to the sixth segment is L2, satisfying 0.2mm≤L1+L2.

8. [Amended according to Rule 26, 29.05.2026] The secondary battery according to claim 7 is characterized in that, The condition L1+L2≤3mm must be met.

9. [Amended according to Rule 26, 29.05.2026] The secondary battery according to claim 7 is characterized in that, It satisfies 0.1mm≤L1 and / or 0.1mm≤L2.

10. The secondary battery according to any one of claims 1 to 9, characterized in that, The secondary battery also includes a second electrode tab, the second electrode tab including a second current collector and a second active material layer stacked together. Along the winding direction of the electrode assembly, the second current collector includes a second coated area with the second active material layer and a second empty foil area without the second active material layer. Along the winding direction of the electrode assembly, the electrode sheet of the second outermost ring of the electrode assembly includes the second electrode sheet, the outermost ring of the second electrode sheet includes the second empty foil area, and the second electrode tab is connected to the second empty foil area of ​​the outermost ring of the second electrode sheet; Along the winding direction of the electrode assembly, the projection of the overlapping structure is located between the projection of the first electrode tab and the projection of the second electrode tab, and the projection direction of the overlapping structure, the projection direction of the first electrode tab, and the projection direction of the second electrode tab are the thickness direction of the first electrode tab.

11. The secondary battery according to claim 10, characterized in that, Along the winding direction of the electrode assembly, the length of the overlapping structure is L, and the minimum distance between the first electrode tab and the second electrode tab is T, satisfying 0.04T≤L≤T.

12. The secondary battery according to claim 5, characterized in that, Along the winding direction of the electrode assembly, the minimum distance between the fourth segment and the first tab is between 1 and 10 mm.

13. The secondary battery according to claim 5, characterized in that, The first electrode further includes a seventh segment and an eighth segment, along the winding direction of the electrode assembly, wherein the seventh segment is connected to the first segment and the eighth segment is connected to the fourth segment; The secondary battery also includes a first adhesive component, which is bonded to both the seventh segment and the eighth segment, and is also bonded to the overlapping structure.

14. The secondary battery according to claim 13, characterized in that, The first adhesive element is also bonded to the first electrode tab.

15. The secondary battery according to claim 13 or 14, characterized in that, Along the width direction of the first electrode, the first electrode tab is connected to the first electrode and extends out of the first electrode; Along the direction in which the first electrode tab extends, the first adhesive member extends beyond the first electrode sheet.

16. [Amended according to Rule 26, 29.05.2026] The secondary battery according to claim 13 is characterized in that, The secondary battery also includes a housing, the electrode assembly is disposed inside the housing, and an electrolyte is also disposed inside the housing; The peel strength between the first adhesive and the seventh segment is F1, the peel strength between the first adhesive and the overlapping structure is F2, and the peel strength between the first adhesive and the eighth segment is F3, satisfying at least one of the following conditions: (1) 0 N / mm ≤ F1 ≤ 0.08 N / mm; (2) 0 N / mm ≤ F2 ≤ 0.08 N / mm; (3) 0 N / mm ≤ F3 ≤ 0.08 N / mm.

17. The secondary battery according to any one of claims 13 to 16, characterized in that, Along the winding direction of the electrode assembly, the length of the first adhesive is S1, which satisfies 2mm≤S1≤20mm.

18. The secondary battery according to claim 17, characterized in that, The requirement is 6mm≤S1≤13mm.

19. The secondary battery according to any one of claims 13 to 18, characterized in that, The material of the first adhesive includes at least one of acrylic resin, polypropylene, or rubber.

20. The secondary battery according to any one of claims 1 to 18, characterized in that, The first electrode tab is welded to the first electrode plate.

21. The secondary battery according to any one of claims 1 to 20, characterized in that, The secondary battery also includes a housing, and the electrode assembly is disposed within the housing. The electrode assembly has a cylindrical structure, and the housing is a metal housing.

22. A method for manufacturing an electrode assembly of a secondary battery as described in any one of claims 1 to 21, characterized in that, Includes the following steps: The first electrode sheet in its unfolded state is stamped with a round bar to form an arc-shaped protrusion; The arc-shaped protrusions on the first electrode are flattened to form the overlapping structure; The overlapping structure is glued and fixed in place; The first electrode, the second electrode, and the separator in their unfolded state are stacked and then wound to form a wound structure, with the overlapping structure located at the outermost ring of the first electrode.

23. An electronic device, characterized in that, Includes the secondary battery as described in any one of claims 1 to 21.

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