Battery

Abstract

The invention relates to the technical field of battery manufacturing, and discloses a battery which comprises a roll core and tabs. At least one end of the roll core is arranged as a tab connecting end, the tab connecting end is formed by winding a head empty foil area of the pole piece, and the central part of the tab connecting end is arranged as a hollow structure. The tab comprises a connecting part and a leading-out part, the connecting part is of an arc-shaped structure, the connecting part is connected with the side wall of the hollow structure of the connecting end of the tab, and the connecting part is connected with the leading-out part. On the premise of reducing the manufacturing cost of the battery, the internal stress of the battery pole piece is ensured to be more uniform, and the piece breaking risk is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery manufacturing, and in particular to a battery. BACKGROUND

[0002] Lithium ion batteries, especially the type pursuing high energy density, are increasingly using silicon-based materials as negative active materials. However, silicon materials will undergo severe volume expansion and contraction during the charging and discharging process of the battery.

[0003] Therefore, in the prior art, cylindrical lithium ion batteries usually use different tab designs to connect the pole pieces inside the winding core to the external terminals. Common designs include tabs directly welded on the end face of the winding core (i.e. middle tabs) or full tab structures covering the entire end face.

[0004] When using a silicon negative electrode, its repeated expansion stress will be directly transmitted to these connection structures. For middle tab designs, stress is easily concentrated at the welding points and their surrounding areas, and under the action of silicon negative electrode expansion and contraction cycles, especially in soft package cylindrical batteries, these stress concentrations or complex structures can cause the negative electrode pieces to break, thereby causing rapid capacity decay or even failure of the battery. For full tab structures, although the stress distribution is more extensive in theory, the manufacturing process is usually more complex and expensive. SUMMARY

[0005] Therefore, the present application provides a tab and a battery to solve the problem of ensuring more uniform stress inside the battery pole piece and reducing the risk of piece breakage under the premise of reducing manufacturing costs.

[0006] The present application provides a battery, comprising:

[0007] A winding core, at least one end of which is provided as a tab connection end, the tab connection end being formed by winding a head empty foil area of a pole piece, and a central part of the tab connection end being provided as a hollow structure;

[0008] A tab, comprising a connection part and a lead-out part, the connection part being provided as an arc-shaped structure, and the connection part being connected to a side wall of the hollow structure of the tab connection end, and the connection part being connected to the lead-out part.

[0009] Beneficial effects: by designing the connection part of the tab as an arc-shaped structure and directly connecting it to the side wall of the hollow structure of the tab connection end, this structure effectively disperses the huge expansion stress generated during the charging and discharging process of the silicon negative electrode. Compared with the traditional middle tab welding method on the end face of the winding core, the side wall connection of the arc-shaped structure makes the stress evenly distributed along the circumferential direction, significantly reducing the risk of pole piece breakage.

[0010] In an alternative embodiment, the lead-out portion comprises a first segment and a second segment, the first segment is connected with the connecting portion, the second segment is connected with the first segment, the first segment and the second segment are arranged at an angle, and the first segment is located in the inner surrounding area of the connecting portion.

[0011] Beneficial effects: The lead-out portion adopts a two-segment design arranged at an angle, specifically, the first segment is connected with the connecting portion, and the second segment carries the tab glue. By limiting the first segment and the second segment in the inner surrounding area of the connecting portion, the compact layout of the tab system is realized. The L-shaped bending structure formed by the first segment and the second segment makes the current transmission path shorter, which can reduce the internal resistance. At the same time, it can also ensure that the whole tab is completely embedded in the core projection space, further optimize the axial size, avoid interference with the shell or other components, improve the space utilization and assembly reliability.

[0012] In an alternative embodiment, the connecting point of the first segment and the second segment is located at the center position of the inner surrounding area of the connecting portion, and the first segment is perpendicular to the second segment.

[0013] Beneficial effects: By limiting the first segment and the second segment in the inner surrounding area of the connecting portion, and the first segment and the second segment, the compact layout of the tab system can be further realized.

[0014] In an alternative embodiment, the lead-out portion and the connecting portion are configured as an integrated structure.

[0015] Beneficial effects: The integrated lead-out portion and connecting portion eliminate the interface weak area of the traditional split-welded tab. Under the extreme working condition of repeated expansion and contraction of the silicon negative electrode, the integrated structure avoids fatigue cracking of the welding point, ensures the continuity of current transmission and the mechanical connection strength, and greatly improves the reliability of the tab in long-period use and the cycle life of the battery.

[0016] In an alternative embodiment, the core further comprises:

[0017] The positive sheet and the negative sheet are provided with the head empty foil area at opposite ends, and the tab is provided with a pair of tabs, and the pair of tabs are respectively connected with the head empty foil area of the positive sheet and the negative sheet.

[0018] Beneficial effects: The positive sheet and the negative sheet are respectively configured with arc-shaped tabs, so that the stress uniform distribution ability is obtained for both poles of the battery. The arc-shaped connection on the positive side can match the expansion characteristics of the silicon negative electrode, and cooperate to maintain the stability of the core structure; the synchronous optimization of the two poles further balances the internal stress field, comprehensively suppresses the risk of sheet fracture, and guarantees the overall reliability of the high-energy-density battery.

[0019] In an alternative embodiment, the positive electrode sheet and the negative electrode sheet each comprise a current collector and a coating layer compounded to the current collector, and a head empty foil area is arranged at one end along the width direction of the current collector, and the head empty foil area extends along the length direction of the current collector.

[0020] In an alternative embodiment, the positive electrode sheet and the negative electrode sheet each have a starting end and a terminal end along the length direction thereof, and the positive electrode sheet and the negative electrode sheet are wound around each other in the direction from the starting end to the terminal end to form the core.

[0021] Beneficial effects: The head empty foil area extending along the width direction of the current collector provides a suitable welding base for the arc-shaped tab connection. Through the precise winding from the starting end to the terminal end, the empty foil area naturally forms a hollow connection structure at the end of the core, ensuring the seamless combination of the arc-shaped tab and the current collector. This design realizes the structural coordination of the electrode sheet, the core and the tab, and lays a foundation for uniform stress conduction.

[0022] In an alternative embodiment, the head empty foil area is provided with a first notch at the end close to the starting end, so that after the winding of the head empty foil area, a hollow structure of the tab connection end is formed, and the connection part is connected to the inner side wall of the hollow structure of the tab connection end.

[0023] Beneficial effects: The layout of the head empty foil area at both ends of the core accurately corresponds to the positions of the double tabs, and the first notch design causes the empty foil area to automatically form a concave tab connection end face after winding. This structure creates an interface for the side wall welding of the arc-shaped tab, avoids the complex shaping process required by the traditional flat end face, significantly improves the production yield and structural consistency, and at the same time strengthens the anti-expansion deformation ability of the end of the core.

[0024] In an alternative embodiment, the head empty foil area is provided with a second notch at the end close to the terminal end, so that after the winding of the head empty foil area, an arc-shaped notch is formed on the outer side wall of the hollow structure of the tab connection end, the connection part is connected to the outer side wall of the hollow structure of the tab connection end, and the connection part is located in the arc-shaped notch.

[0025] Beneficial effects: The second notch design causes the empty foil area to automatically form a tab connection end with an arc-shaped notch outside after winding. The arc-shaped notch creates an interface for the side wall welding of the arc-shaped tab, avoids the complex shaping process required by the traditional flat end face, significantly improves the production yield and structural consistency, and at the same time strengthens the anti-expansion deformation ability of the end of the core.

[0026] In an alternative embodiment, a third gap is arranged on the head empty foil area, and the third gap is located between the first gap and the second gap, so that a connecting gap is formed on the hollow structure of the tab connecting end after the head empty foil area is completely wound, and the first section passes through the connecting gap.

[0027] Beneficial effect: the third gap design makes the empty foil area automatically form a tab connecting end with a connecting gap after winding, and the first section passes through the connecting gap, so that the second section is located in the hollow structure of the tab connecting end.

[0028] In an alternative embodiment, the connecting part of the arc-shaped structure corresponds to a central angle A, wherein 90°≤A<360°, and the connecting part is arranged as an open ring structure with an opening, and the opening is used for injecting electrolyte into the winding core.

[0029] Beneficial effect: the opening of the open ring connecting part forms an electrolyte injection channel, which breaks through the limitation of the injection process of the closed ring-shaped tab. This design takes into account the mechanical advantages of the ring-shaped structure and the injection requirements, without the need for additional openings or complex injection systems, which guarantees battery performance and simplifies the manufacturing process, reducing production costs. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed in the description of the specific embodiments or prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0031] Figure 1 A structural schematic diagram of a battery according to an embodiment of the present application;

[0032] Figure 2 A structural schematic diagram of a winding core according to an embodiment of the present application;

[0033] Figure 3 A structural schematic diagram of a tab according to an embodiment of the present application;

[0034] Figure 4 A structural schematic diagram of a metal strip structure according to an embodiment of the present application;

[0035] Figure 5 A structural schematic diagram of a positive electrode sheet according to an embodiment of the present application;

[0036] Figure 6 A structural schematic diagram of a negative electrode sheet according to an embodiment of the present application;

[0037] Figure 7The structural schematic diagram of the base and the welding head in the embodiment of the present application.

[0038] Explanation of reference signs:

[0039] 1, core; 101, tab connecting end; 102, positive electrode sheet; 103, negative electrode sheet; 104, current collector; 1041, coating layer; 1042, head empty foil area; 1043, first notch; 1044, second notch; 1045, third notch; 2, tab; 201, connecting part; 202, leading-out part; 2021, first section; 2022, second section; 203, tab adhesive; 204, opening; 3, metal strip structure; 301, first side; 302, second side; 4, base; 401, through slot; 5, welding head; 501, arc-shaped groove. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0041] The embodiments of the present application will be described below with reference to the drawings. Figures 1 to 7

[0042] According to the embodiments of the present application, a battery is provided, which comprises a core 1 and a tab 2. At least one end of the core 1 is arranged as a tab connecting end 101, which is formed by winding the head empty foil area 1042 of the electrode sheet, and the central part of the tab connecting end 101 is arranged as a hollow structure. The tab 2 comprises a connecting part 201 and a leading-out part 202. The connecting part 201 is arranged as an arc-shaped structure, and the connecting part 201 is connected to the side wall of the hollow structure of the tab connecting end 101. The connecting part 201 is connected to the leading-out part 202.

[0043] It should be noted that, as shown in Figure 1 and Figure 2 , the tab connecting end 101 of the core 1 and the connecting part 201 of the tab 2 can both be arranged as an arc-shaped structure, so that the stress is uniformly distributed along the circumferential direction. The leading-out part 202 can extend in the axial direction of the connecting part 201 of the arc-shaped structure, away from the core 1, so that the part of the leading-out part 202 used for connecting to an external device is away from the core 1, facilitating the operation of connecting to the external device.

[0044] ​In the embodiment, the connecting part 201 of the tab 2 is designed as an arc structure and directly connected with the side wall of the hollow structure of the tab connecting end 101 of the winding core 1, which effectively disperses the huge expansion stress generated in the charging and discharging process of the silicon negative electrode. Compared with the traditional mode of centrally welding the tab on the end surface of the winding core 1, the arc structure side wall connection makes the stress uniformly distributed along the circumferential direction, significantly reducing the risk of tab fracture. At the same time, the arc segment connection fully utilizes the axial space of the winding core 1, avoids the additional occupation of the battery height by the traditional tab welding area, and helps to improve the energy density of the battery and simplify the internal structure.

[0045] In one embodiment, as shown in Figure 3 The lead-out part 202 includes a first segment 2021 and a second segment 2022, wherein the first segment 2021 includes opposite first and second ends, the first end of the first segment 2021 is connected with the connecting part 201, the second segment 2022 is connected with the second end of the first segment 2021, and the first segment 2021 and the second segment 2022 are arranged at an included angle, and the first segment 2021 is located in the inner region of the connecting part 201.

[0046] It should be noted that the extension direction of the first segment 2021 of the lead-out part 202 is parallel to the radial direction of the arc structure connecting part 201, and specifically, the first and second ends of the first segment 2021 are oppositely arranged along the extension direction thereof, the first end of the first segment 2021 is connected with the connecting part 201, and the second end of the first segment 2021 is arranged along the radial direction of the connecting part 201 to point to the center of the connecting part 201, so that the second segment 2022 of the lead-out part 202 can be located in the inner region of the connecting part 201.

[0047] It should be noted that the extension direction of the first segment 2021 of the lead-out part 202 is parallel to the radial direction of the arc structure connecting part 201, and specifically, the first and second ends of the first segment 2021 are oppositely arranged along the extension direction thereof, the first end of the first segment 2021 is connected with the connecting part 201, and the second end of the first segment 2021 is arranged along the radial direction of the connecting part 201 to point to the center of the connecting part 201, so that the second segment 2022 of the lead-out part 202 can be located in the inner region of the connecting part 201.

[0048] Optionally, the included angle between the first segment 2021 and the second segment 2022 of the lead-out part 202 can be 90°.

[0049] Optionally, the included angle between the first segment 2021 and the second segment 2022 of the lead-out part 202 can be 60° to 120°.

[0050] In the embodiment, the lead-out portion 202 adopts a two-segment design arranged at an angle, specifically, a first segment 2021 is connected with the connecting portion 201, and a second segment 2022 bears the tab adhesive 203. By limiting the first segment 2021 and the second segment 2022 in the inner region of the connecting portion 201, the compact layout of the tab system is realized. The L-shaped bending structure formed by the first segment 2021 and the second segment 2022 makes the current transmission path shorter, which can reduce the internal resistance. At the same time, it can also ensure that the tab 2 is completely embedded in the projection space of the winding core 1, further optimize the axial size, avoid interference with the shell or other components, improve the space utilization and assembly reliability.

[0051] In one embodiment, as shown in Figure 3 the second segment 2022 is provided with the tab adhesive 203.

[0052] It should be noted that the tab adhesive 203 is arranged at the middle of the second segment 2022 or the end portion away from the first segment 2021.

[0053] In the embodiment, the tab adhesive 203 can block the path of electrolyte leakage outward through the gap between the metal and the shell, and prevent external moisture from entering the battery interior, thereby ensuring the stability of the chemical environment in the battery interior. By arranging the tab adhesive 203 on the second segment 2022 of the lead-out portion 202, the tab adhesive 203 can be away from the high-temperature welding area, thereby avoiding the risk of thermal damage.

[0054] In one embodiment, the connection point of the first segment 2021 and the second segment 2022 is located at the center position of the inner region of the connecting portion 201, and the first segment 2021 is perpendicular to the second segment 2022.

[0055] In the embodiment, the first segment 2021 and the second segment 2022 are limited in the inner region of the connecting portion 201, and the first segment 2021 and the second segment 2022 can further realize the compact layout of the tab system.

[0056] In one embodiment, as shown in Figure 4 the lead-out portion 202 and the connecting portion 201 are configured as an integrated structure.

[0057] It should be noted that the tab 2 can be provided as an L-shaped metal strip structure 3 including a first edge 301 and a second edge 302 connected to each other, and the first edge 301 and the second edge 302 are arranged at an angle. The tab 2 is formed by bending the L-shaped metal strip structure 3. Specifically, the part of the first edge 301 of the L-shaped metal strip structure 3 away from the second edge 302 is bent to form an arc-shaped structure, and the bent part is the connecting part 201. The part of the first edge 301 of the L-shaped metal strip structure 3 close to the second edge 302 and not bent is the first section 2021. The second edge 302 of the L-shaped metal strip structure 3 is the second section 2022.

[0058] In this embodiment, the integrally formed lead-out part 202 and the connecting part 201 eliminate the interface weak area of the conventional split-welding tab 2. Under the extreme working condition of repeated expansion and contraction of the silicon negative electrode, the integral structure avoids fatigue cracking of the welding point, ensures the continuity of current transmission and the mechanical connection strength, and greatly improves the reliability of the tab 2 in long-period use and the cycle life of the battery.

[0059] In one embodiment, as shown in Figure 1 the winding core 1 further includes a positive electrode sheet 102 and a negative electrode sheet 103, and the positive electrode sheet 102 and the negative electrode sheet 103 are provided with a head empty foil area 1042 at opposite ends. A pair of tabs 2 are provided, and the pair of tabs 2 are respectively connected to the head empty foil area 1042 of the positive electrode sheet 102 and the negative electrode sheet 103.

[0060] It can be understood that the pair of tabs 2 are respectively provided as a positive tab and a negative tab, wherein the positive tab is connected to the positive electrode sheet 102, and the negative tab is connected to the negative electrode sheet 103.

[0061] In this embodiment, the positive electrode sheet 102 and the negative electrode sheet 103 are respectively provided with arc-shaped tabs 2, so that the stress uniform distribution capability is obtained for both positive and negative electrodes of the battery. The arc-shaped connection on the positive electrode side can match the expansion characteristics of the silicon negative electrode, and cooperatively maintain the structural stability of the winding core 1. The synchronous optimization of both electrodes further balances the internal stress field, comprehensively suppresses the risk of electrode sheet fracture, and guarantees the overall reliability of the high-energy-density battery.

[0062] In one embodiment, as shown in Figure 5 and Figure 6 the positive electrode sheet 102 and the negative electrode sheet 103 each include a current collector 104 and a coating layer 1041 applied to the current collector 104, and are provided with a head empty foil area 1042 at one end in the width direction of the current collector 104, and the head empty foil area 1042 extends in the length direction of the current collector 104.

[0063] It should be noted that the current collector 104 serves as the conductive framework of the electrode and undertakes the core role of current collection and transmission. The positive electrode current collector 104 is usually made of aluminum foil, which can form a dense oxide film in a high-voltage environment, is resistant to electrolyte corrosion and has a conductive property meeting the requirements. The negative electrode current collector 104 is usually made of copper foil, which has a lower resistivity, avoids forming an alloy with lithium, and has a ductility suitable for the expansion of the silicon negative electrode. The coating 1041 can provide an electrochemical reaction site. The head empty foil area 1042 is located at one end of the current collector 104 in the width direction and extends along the length direction. The metal foil bare area without coating 1041 can serve as the base body for welding the tab 2 at the end of the wound core 1 after winding. When the silicon negative electrode expands, the stress of the electrode piece is uniformly transmitted to the arc-shaped tab 2 through the empty foil area, avoiding the direct stress fracture of the coating 1041 area, and the extension direction of the head empty foil area 1042 is consistent with the winding direction, ensuring that the multiple layers of the empty foil are precisely stacked to form an arc-shaped welding surface after winding.

[0064] In one embodiment, as shown in FIGS. 1 and 2, the positive electrode piece 102 and the negative electrode piece 103 each have a starting end and a terminal end along the length direction thereof, and the positive electrode piece 102 and the negative electrode piece 103 are wound around each other along the direction from the starting end to the terminal end to form a wound core 1. Figure 5 and Figure 6 In one embodiment, as shown in FIGS. 1 and 2, the positive electrode piece 102 and the negative electrode piece 103 each have a starting end and a terminal end along the length direction thereof, and the positive electrode piece 102 and the negative electrode piece 103 are wound around each other along the direction from the starting end to the terminal end to form a wound core 1.

[0065] It should be noted that the empty foil area is also provided at the terminal end of the positive electrode piece 102 and extends along the width direction of the positive electrode piece 102. This is a commonly used empty foil area design scheme in the prior art, which can be used together with the head empty foil area 1042 or can be abandoned and only the head empty foil area 1042 is used.

[0066] In this embodiment, the head empty foil area 1042 extending along the width direction of the current collector 104 provides a suitable welding base body for connecting the arc-shaped tab 2. Through precise winding from the starting end to the terminal end, the empty foil area naturally forms a hollow connection structure at the end of the wound core 1, ensuring the seamless combination of the arc-shaped tab 2 and the current collector 104. This design realizes the structural cooperation of the electrode piece, the wound core 1 and the tab 2 and lays a foundation for uniform stress conduction.

[0067] In one embodiment, the head empty foil area 1042 is provided with a first notch 1043 near the end of the starting end, so that after the winding of the head empty foil area 1042, a hollow structure of the tab connecting end 101 is formed, and the connecting part 201 is connected to the inner side wall of the hollow structure of the tab connecting end 101.

[0068] In the embodiment, the head empty foil area 1042 is arranged at both ends of the winding core 1 and corresponds to the position of the bipolar lug 2. The first notch 1043 is designed to automatically form the connecting end surface of the concave bipolar lug 2 after winding. The structure creates an interface for the side wall welding of the arc-shaped bipolar lug 2, avoids the complex shaping process required by the traditional flat end surface, significantly improves the production yield and structural consistency, and strengthens the anti-expansion deformation ability of the end of the winding core 1.

[0069] In one embodiment, the second notch 1044 is arranged at the end of the head empty foil area 1042 close to the terminal, so that the head empty foil area 1042 forms an arc-shaped notch on the outer side wall of the hollow structure of the bipolar lug connecting end 101 after winding. The connecting part 201 is connected to the outer side wall of the hollow structure of the bipolar lug connecting end 101, and the connecting part 201 is located in the arc-shaped notch.

[0070] In the embodiment, the second notch 1044 is designed to automatically form the bipolar lug connecting end 101 with an arc-shaped notch outside after winding. The arc-shaped notch creates an interface for the side wall welding of the arc-shaped bipolar lug 2, avoids the complex shaping process required by the traditional flat end surface, significantly improves the production yield and structural consistency, and strengthens the anti-expansion deformation ability of the end of the winding core.

[0071] In one embodiment, the third notch 1045 is arranged on the head empty foil area 1042, and the third notch 1045 is located between the first notch 1043 and the second notch 1044. After the winding of the head empty foil area 1042 is completed, a connecting notch is formed on the hollow structure of the bipolar lug connecting end 101, and the first section 2021 passes through the connecting notch.

[0072] Optionally, a plurality of third notches 1045 can be arranged on the head empty foil area 1042.

[0073] In the embodiment, the third notch 1045 is designed to automatically form the bipolar lug connecting end 101 with a connecting notch outside after winding, which can be used for the first section 2021 to pass through, so that the second section 2022 is located in the hollow structure of the bipolar lug connecting end 101.

[0074] The first notch 1043, the second notch 1044 and the third notch 1045 can be formed by cutting the current collector 104.

[0075] In one embodiment, the central angle of the arc-shaped connecting part 201 is A, wherein 90°≤A<360°, the connecting part 201 is arranged as an open loop structure with an opening 204, and the opening 204 is used for injecting electrolyte into the winding core 1.

[0076] Optionally, the central angle of the arc-shaped connecting part 201 is 90°.

[0077] Optionally, the connection part 201 of the arc structure corresponds to a central angle of 180°.

[0078] Optionally, the connection part 201 of the arc structure corresponds to a central angle of 358°, which is the preferred central angle of the connection part 201, making it closest to a complete annular structure.

[0079] It can be understood that the opening 204 of the connection part 201 includes two opposite end faces, one of which can be connected to the first section 2021.

[0080] It should be noted that the opening 204 of the connection part 201 is the end face of the first edge 301 of the L-shaped metal strip structure 3 away from the second edge 302, and after bending, the gap between the first edge 301 side face.

[0081] In this embodiment, the opening 204 of the open-loop connection part 201 forms an electrolyte injection channel, breaking the limitation of the injection process of the closed annular tab 2. This design takes into account the mechanical advantages of the annular structure and the injection requirements, without the need for additional openings or complex injection systems, ensuring battery performance and simplifying the manufacturing process, reducing production costs.

[0082] In one embodiment, as shown in Figure 7 The base 4 is provided in a disc-shaped structure, and a through groove 401 is formed in the middle part. The through groove 401 is provided in a strip-shaped structure, and one end of the through groove 401 extends along the radial direction of the base 4 and penetrates through the peripheral surface of the base 4. The through groove 401 is used to accommodate the first section 2021 of the lead-out part 202, and the outer peripheral surface of the base is matched with the inner side wall of the connection part 201. The welding head 5 is provided in a pair, and the arc-shaped groove 501 is provided on the welding head 5. The arc-shaped grooves 501 on the pair of welding heads 5 can cooperate with each other to form a circular structure, and can be sleeved on the outside of the tab connecting end 101 of the core 1, thereby limiting the tab connecting end 101 of the core 1.

[0083] After the base 4 and the welding head 5 limit the tab 2 and the tab connecting end 101 of the core 1 respectively, the tab 2 and the tab connecting end 101 of the core 1 are welded, which can ensure the welding precision and stability.

[0084] Although the embodiments of the present application have been described in conjunction with the accompanying drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A battery, characterized in that, include: The core (1) has at least one end configured as a tab connection end (101), the tab connection end (101) is formed by winding the head empty foil area (1042) of the electrode sheet, and the center part of the tab connection end (101) is configured as a hollow structure. The tab (2) includes a connecting part (201) and a lead-out part (202). The connecting part (201) is configured as an arc-shaped structure and is connected to the side wall of the hollow structure of the tab connecting end (101). The connecting part (201) is connected to the lead-out part (202).

2. The battery according to claim 1, characterized in that, The lead-out portion (202) includes a first segment (2021) and a second segment (2022). The first segment (2021) is connected to the connecting portion (201), and the second segment (2022) is connected to the first segment (2021). The first segment (2021) and the second segment (2022) are arranged at an angle, and the first segment (2021) is located within the inner perimeter area of ​​the connecting portion (201).

3. The battery according to claim 2, characterized in that, The connection point between the first segment (2021) and the second segment (2022) is located at the center of the inner perimeter area of ​​the connecting part (201), and the first segment (2021) and the second segment (2022) are perpendicular to each other.

4. The battery according to claim 2, characterized in that, The core (1) includes: A positive electrode (102) and a negative electrode (103) are provided, with the head empty foil area (1042) provided at opposite ends of the positive electrode (102) and the negative electrode (103). A pair of tabs (2) are provided, and the pair of tabs (2) are respectively connected to the head empty foil area (1042) of the positive electrode (102) and the negative electrode (103).

5. The battery according to claim 4, characterized in that, Both the positive electrode (102) and the negative electrode (103) include a current collector (104) and a coating (1041) composited on the current collector (104). A head empty foil area (1042) is provided at one end along the width direction of the current collector (104), and the head empty foil area (1042) extends along the length direction of the current collector (104).

6. The battery according to claim 5, characterized in that, The positive electrode (102) and the negative electrode (103) each have a starting end and a terminal end along their length direction. The positive electrode (102) and the negative electrode (103) are wound around each other along the direction from the starting end to the terminal end to form the core (1).

7. The battery according to claim 6, characterized in that, The head empty foil area (1042) is provided with a first notch (1043) at the end near the starting end, so that after the head empty foil area (1042) is wound, it forms the hollow structure of the tab connection end (101), and the connection part (201) is connected to the inner wall of the hollow structure of the tab connection end (101).

8. The battery according to claim 7, characterized in that, The head empty foil area (1042) is provided with a second notch (1044) near the end of the terminal, so that after the head empty foil area (1042) is wound, an arc-shaped notch is formed on the outer wall of the hollow structure of the electrode connecting end (101). The connecting part (201) is connected to the outer wall of the hollow structure of the electrode connecting end (101), and the connecting part (201) is located in the arc-shaped notch.

9. The battery according to claim 8, characterized in that, A third notch (1045) is provided on the head empty foil area (1042). The third notch (1045) is located between the first notch (1043) and the second notch (1044), so that after the head empty foil area (1042) is wound, a connection notch is formed on the hollow structure of the electrode connection end (101), and the first segment (2021) passes through the connection notch.

10. The battery according to claim 1, characterized in that, The connecting part (201) of the arc structure has a center angle of A, where 90°≤A<360°. The connecting part (201) is configured as an open-loop structure with an opening (204), and the opening (204) is used to inject electrolyte into the core (1).

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