Battery, battery module and battery pack

Abstract

A battery (100), a battery module (1000) and a battery pack. The battery (100) comprises a case (101), a current collecting disc (106), and a plurality of first welding portions (109); the case (101) is provided with a top and a bottom (103), and a cavity (102) is formed in the case (101); the current collecting disc (106) is arranged in the cavity (102); the plurality of first welding portions (109) are formed on the side of the current collecting disc (106) close to the bottom (103); the current collecting disc (106) is welded to the bottom (103) by means of the plurality of first welding portions (109); the plurality of first welding portions (109) are arranged around a circle center of the current collecting disc (106); and the distance between each first welding portion (109) and the circle center of the current collecting disc (106) is greater than the distance between the first welding portion (109) and an edge of the current collecting disc (106).

Description

Battery, battery module and battery pack

[0001] This application claims priority to Chinese patent applications filed with the China Patent Office on December 18, 2023, with application numbers 202323459079.8 and 202311750665.X. The entire contents of the above applications are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery, a battery module and a battery pack. Background Art

[0003] In the battery lead-out structure in which the battery casing serves as one pole of the battery, a current collecting plate is usually used as a conductive medium to lead the current from one pole of the battery cell to the battery casing, so that the casing is charged and serves as one pole of the battery. The specific method is to weld one side of the current collecting plate to the battery cell and the other side to the bottom of the casing. In the related art, the casing and the current collecting plate are welded in such a way that the welding part between the current collecting plate and the bottom of the casing is set in the middle position of the current collecting plate. SUMMARY OF THE INVENTION

[0004] However, this welding method has the problem that the welded body formed by welding the battery cell and the current collecting plate and the bottom of the shell have insufficient torsional resistance. During subsequent assembly, the welded body and the steel shell are easily twisted due to external forces, thereby causing the weld point between the current collecting plate and the shell to break, resulting in poor welding.

[0005] In a first aspect, the present application provides a battery. The battery comprises:

[0006] a shell having a top and a bottom, with a cavity formed in the shell;

[0007] a collecting plate disposed in the cavity; and

[0008] Multiple first welding portions are formed on one side of the collecting plate close to the bottom. The collecting plate is welded to the bottom through the multiple first welding portions. The multiple first welding portions are arranged around the center of the collecting plate. The distance from each first welding portion to the center of the collecting plate is greater than the distance from the first welding portion to the edge of the collecting plate.

[0009] In a second aspect, the present application further provides a battery module. The battery module includes:

[0010] Multiple batteries, each battery including a shell, a current collecting tray, and multiple first welding portions, wherein the shell has a cavity formed therein; the current collecting tray is disposed in the cavity; the multiple first welding portions are formed on a side of the current collecting tray near the bottom of the shell, the current collecting tray is welded to the bottom of the shell via the multiple first welding portions, the multiple first welding portions are arranged around the center of the current collecting tray, and the distance from each first welding portion to the center of the current collecting tray is greater than the distance from the first welding portion to the edge of the current collecting tray; and,

[0011] The connecting piece is formed with a plurality of connecting parts, and each connecting part is connected to a corresponding battery.

[0012] In a third aspect, the present application further provides a battery pack. The battery pack includes:

[0013] cabinet; and

[0014] The battery module is arranged in the box. Beneficial effects

[0015] In the technical solution of the present application, the collecting plate is welded to the shell through multiple first welding parts. By being connected through multiple first welding parts, the welding contact area between the collecting plate and the shell is increased, so that the connection stability between the collecting plate and the shell is enhanced, and it can withstand larger torque. At the same time, the larger welding area can also meet the fast charging overcurrent requirements of the battery and improve the performance of the battery. It is known from the relationship between distance and torque that when the first welding part is set close to the edge of the collecting plate, the welding force applied to the first welding part will be reduced. By limiting the distance from the first welding part to the center of the collecting plate to be greater than the distance from the first welding part to the edge of the collecting plate, the welding force applied to the first welding part is reduced, the welding difficulty is reduced, the welding strength is improved, and at the same time, the torque resistance of the collecting plate and the bottom of the shell is improved, the collecting plate is prevented from being separated from the shell, and the safety factor of the battery is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic structural diagram of a battery provided by some implementations of the present application;

[0017] FIG2 is a partial cross-sectional view of the battery in FIG1 ;

[0018] FIG3 is a schematic structural diagram of the current collecting disk of FIG1 from a first perspective;

[0019] FIG4 is an enlarged schematic diagram of A in FIG2 ;

[0020] FIG5 is a bottom perspective view of the battery in FIG1 ;

[0021] FIG6 is a cross-sectional view of the current collecting plate in FIG1 ;

[0022] FIG7 is a schematic diagram of the structure of a battery module provided by some implementations of the present application.

[0023] Description of reference numerals:

[0024] 100. Battery; 101. Shell; 102. Cavity; 103. Bottom; 104. First side; 105. Second side; 106. Collecting plate; 107. Third side; 108. Fourth side; 109. First welding portion; 110. First side edge; 111. Second side edge; 112. Shell; 113. Extension portion; 114. Core material; 115. Outer layer; 116. Second welding portion; 117. First connecting section; 118. Annular boss; 119. Second connecting section; 1000. Battery module; 200. Connecting piece; 201. Connecting portion; 120. Third welding portion; 122. Winding core; 123. Welding accommodating portion. Modes for Carrying Out the Invention

[0025] In the related art, the shell and the current collecting plate are welded in a manner that the welding portion between the current collecting plate and the bottom of the shell is set in the middle of the current collecting plate. This welding method has the problem that the welded body formed by the welding of the battery cell and the current collecting plate and the bottom of the shell have insufficient torsional resistance. In subsequent assembly, the welded body and the steel shell may be easily twisted due to external forces, thereby causing the weld point between the current collecting plate and the shell to break, resulting in poor welding.

[0026] In view of this, the present application proposes a battery. Figures 1 to 6 are structural schematic diagrams of an embodiment of the battery provided by the present application. The battery provided by the present application has a stable structure, strong torque resistance, and a high safety factor. The battery will be described in detail below in conjunction with the main drawings.

[0027] Referring to Figures 1, 2 and 3, the battery 100 includes a shell 101, a current collecting tray 106 and a plurality of first welding portions 109. A cavity 102 is formed in the shell 101; the current collecting tray 106 is disposed in the cavity 102; a plurality of first welding portions 109 are formed on a side of the current collecting tray 106 close to the bottom 103 of the shell 101, and the current collecting tray 106 is welded to the bottom 103 of the shell 101 through the plurality of first welding portions 109. The plurality of first welding portions 109 are arranged around the center of the current collecting tray 106, and the distance from each first welding portion 109 to the center of the current collecting tray 106 is greater than the distance from the first welding portion 109 to the edge of the current collecting tray 106.

[0028] In the technical solution of the present application, the current collecting disc 106 is welded to the shell 101 through multiple first welding portions 109. By connecting the multiple first welding portions 109, the welding contact area between the current collecting disc 106 and the shell 101 is increased, so that the connection stability of the current collecting disc 106 and the shell 101 is enhanced, and it can withstand larger torque. At the same time, the larger welding area can also meet the fast charging overcurrent requirements of the battery 100, thereby improving the performance of the battery 100. According to the relationship between distance and torque, when the first welding portion 109 is set close to the edge of the current collecting disc 106, the welding force applied to the first welding portion 109 will be reduced. By limiting the distance from the first welding portion 109 to the center of the current collecting disc 106 to be greater than the distance from the first welding portion 109 to the edge of the current collecting disc 106, the welding force applied to the first welding portion 109 is reduced, the welding difficulty is reduced, the welding strength is improved, and the torque resistance of the current collecting disc 106 and the bottom 103 of the shell 101 is improved, thereby preventing the current collecting disc 106 from separating from the shell 101 and improving the safety factor of the battery 100.

[0029] Specifically, in this embodiment, referring to Figure 4, the bottom 103 of the shell 101 has two side surfaces that are opposite to each other. Taking the length direction of the battery 100 as an example, the two side surfaces of the bottom 103 of the shell 101 are respectively a first side surface 104 and a second side surface 105. The first side surface 104 is a side surface located inside the cavity 102, and the second side surface 105 is opposite to the first side surface 104. The second side surface 105 is a side surface located outside the cavity 102. Similarly, the collecting plate 106 has two side surfaces that are opposite to each other, namely a third side surface 107 and a fourth side surface 108. The third side surface 107 is a side surface facing the bottom 103 of the shell 101, and the fourth side surface 108 is a side surface facing away from the bottom 103 of the shell 101. Specifically, a plurality of first welding portions 109 are formed on the third side surface 107.

[0030] It should be noted that during the use of the battery 100, displacement may occur, such as rotation, shaking, etc. During the rotation and shaking of the battery 100, the current collector plate 106 and the housing 101 may move in opposite directions. The winding core 122 inside the battery 100 forms a couple due to inertia, resulting in the welding between the current collector plate 106 and the bottom 103 of the housing 101 being broken. Through testing, it is found that the distance (here the distance refers to the distance between the first welding part 109 and the center of the current collector plate 106) is inversely proportional to the anti-torque force. Therefore, when the first welding part 109 is closer to the center of the current collector plate 106, the force received by the current collector plate 106 is greater. To avoid the situation where the current collector plate 106 is detached from the bottom 103 of the housing 101, specifically, in this embodiment, each first welding part 109 has a first side 110 close to the center of the current collector plate 106 and a second side 111 far from the center of the current collector plate 106. Define the radius of the current collector plate 106 as D1, the shortest distance between the first side 110 and the center of the current collector plate 106 as D2, the inertial force received by the current collector plate 106 as F1, the welding force received by the first welding part 109 as F2, and the number of the first welding parts 109 as n. Among them, F1D1 < nF2D2. With such a limitation, during the rotation and shaking of the battery 100, it can prevent the winding core 122 from rotating together with the current collector plate 106, avoid the welding break between the current collector plate 106 and the bottom 103 of the housing 101, and improve the connection strength between the current collector plate 106 and the bottom 103 of the housing 101.

[0031] It should be noted that when the first welding part 109 is arc-shaped, the shortest distance from the first side 110 to the center of the current collector plate 106 is the radius of the arc; when the first welding part 109 is linear, the shortest distance from the first side 110 to the center of the current collector plate 106 is the distance from the center point of the first side to the center of the current collector plate 106.

[0032] Specifically, in actual application, it is necessary to first determine the shortest distance (i.e., D2) from the first side 110 to the center of the collecting plate 106. The position of the first welding portion 109 can be determined by D2, and then the position of the second side 111 is determined according to the width of the first welding portion 109. In this way, the position of the first welding portion 109 can be confirmed. Specifically, in this embodiment, the distance between the first side 110 and the center of the collecting plate 106 is D2, where 7.0 mm ≤ D2 ≤ 9.4 mm. More specifically, the first side 1 The distance from 10 to the center of the collecting plate 106 can be 7.0mm, 7.2mm, 7.4mm, 7.6mm, 7.8mm, 8.0mm, 8.1mm, 8.2mm, 8.3mm, 8.4mm, 8.5mm, 8.61mm, 8.62mm, 8.64mm, 8.65mm, 8.68mm, 8.69mm, 8.7mm, 8.8mm, 8.85mm, 8.9mm, 9.0mm, 9.1mm, 9.2mm, 9.3mm, and 9.4mm. In some embodiments, the distance between the first side 110 and the second side 111 is D3, wherein 0.1mm≤D3≤0.3mm. More specifically, the distance between the first side 110 and the second side 111 can be 0.1mm, 0.12mm, 0.14mm, 0.15mm, 0.16mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, or 0.30mm. In one embodiment, the distance between the first side 110 and the center of the collecting plate 106 is 8.7mm, and the distance between the first side 110 and the second side 111 is 0.3mm.

[0033] Please refer to Figures 2 and 3. In order to ensure the uniformity of force on the collecting plate 106 and the bottom 103 of the shell 101, the distance between each two adjacent first welding parts 109 is the same; that is, the multiple first welding parts 109 are equidistantly distributed. The purpose of such arrangement is to ensure the stability of the connection between the collecting plate 106 and the bottom 103 of the shell 101, to evenly distribute the torque, and to avoid concentrating the torque in a certain place, resulting in excessive force there and causing breakage.

[0034] It should be noted that the specific shape of the first welding portion 109 is not limited. Specifically, in this embodiment, the shape of the first welding portion 109 can be an arc, a ring, a C-shape, or a spiral.

[0035] Please refer to Figure 1. The battery 100 also includes a winding core 122 and multiple second welding portions 116. In this embodiment, a pole tab is provided on the winding core 122, and the current collecting plate 106 is welded to the pole tab through multiple second welding portions 116. Specifically, the multiple second welding portions 116 are formed on the side of the current collecting plate 106 away from the bottom 103 (the current collecting plate 106 has a third side 107 and a fourth side 108, the fourth side 108 is the side of the current collecting plate 106 away from the bottom, and the third side 107 is the side of the current collecting plate 106 facing the bottom. It should be noted that multiple first welding portions 109 are formed on the third side 107, and multiple second welding portions 116 are formed on the fourth side 108). The current collecting plate 106 is welded to the pole tab through multiple second welding portions 116. The pole tab is provided on the winding core 122, that is, the welding plate is welded to the winding core 122 through multiple second welding portions 116. Specifically, considering the stability of the connection, multiple second welding portions 116 are arranged around the center of the current collecting plate 106, and the distance between each two adjacent second welding portions 116 is the same. The multiple second welding portions 116 are equidistantly distributed, which evenly distributes the welding force between the current collecting plate 106 and the pole tab, thereby improving the stability of the connection between the current collecting plate 106 and the pole tab; more specifically, each second welding portion 116 is staggered with each first welding portion 109. The staggered arrangement means that the orthographic projections of the first welding portion 109 and the second welding portion 116 on the current collecting plate 106 do not overlap. By staggering the first welding portion 109 and the second welding portion 116, mutual interference can be avoided, the stability of welding is improved, and the safety factor of the battery 100 is effectively improved.

[0036] It should be noted that there is no limitation on the manner in which the first welding portion 109 and the second welding portion 116 are staggered, as long as there is no interference between them. Specifically, in this embodiment, please refer to Figures 2 and 4. The collecting plate 106 includes a first connecting segment 117 and a second connecting segment 119 arranged around the first connecting segment 117. The second connecting segment 119 is recessed toward the bottom 103 of the shell 101 to form an annular boss 118. It should be noted that the first connecting segment 117 and the second connecting segment 119 are integrally formed. During the actual processing, the collecting plate is placed on a stamping machine, and part of the second connecting segment 119 is stamped to form the annular boss 118. In some embodiments, the annular boss 118 has a side close to the bottom 103 of the shell 101, and multiple first welding portions 109 are formed under the annular boss 118 (the bottom here refers to the side of the annular boss 118 close to the bottom 103 of the shell 101), the first connecting section 117 has a side close to the winding core 122, and multiple second welding portions 116 are formed on the first connecting section 117 (the top here refers to the side of the first connecting section 117 close to the winding core 122). Specifically, in this embodiment, the collecting plate 106 itself is divided into different parts (i.e., the annular boss 118 area and the second connecting section 119 area) by providing an annular boss 118, the first welding portion 109 is provided on the annular boss 118, and the second welding portion 116 is provided on the second connecting section 119. By dividing the collecting plate 106 into different areas, the first welding portion 109 and the second welding portion 116 are provided in different areas, thereby staggering the first welding portion 109 and the second welding portion 116. Specifically, the height of the second welding portion 116 protruding from the collecting plate 106 is less than the height of the annular boss 118, thereby ensuring that the annular boss 118 can be in good contact with the inner side surface of the shell 101, thereby improving the stability of the connection between the bottom 103 of the shell 101 and the collecting plate 106.

[0037] Specifically, in this embodiment, the bottom 103 of the shell 101 is used as an electrode, so the shell 101 is charged. Considering the safety of the battery 100, the battery 100 further includes a shell 112, which is sleeved on the shell 101. The shell 112 is wrapped with an insulating film. The purpose of providing the insulating film is: on the one hand, the shell 112 is wrapped around the outside of the shell 101 to isolate the shell 101 from the outside and prevent the shell 101 from being oxidized and corroded. At the same time, the insulating film can also protect the shell 112 and prevent the shell 112 from being corroded. On the other hand, it can prevent the current on the shell 101 from being transferred. To the outside world, the safety of the battery 100 is improved. Specifically, in this embodiment, referring to Figures 1 and 5, one end of the outer shell 112, which is adjacent to the bottom 103 of the housing 101, is folded toward the bottom 103 of the housing 101 to form an extension 113. The extension 113 is located below the bottom 103 of the housing 101 (the "below" here refers to the second side surface 105, i.e., the extension 113 covers the second side surface 105), and the orthographic projection of the extension 113 on the bottom 103 of the housing 101 covers the orthographic projections of the multiple first welds 109 on the bottom 103 of the housing 101. This configuration ensures that the extension 113 can wrap around the first welds 109, protecting them from oxidation and corrosion, which could lead to disconnection of the current collecting plate 106 from the bottom 103 of the housing 101. In one embodiment, the first welds 109 are located in the middle of the extension 113.

[0038] It should be noted that the length of the extension portion 113 is related to the size and position of the first welding portion 109. It is necessary to consider both being able to fully cover the first welding portion 109 to avoid exposure of the welds on the first welding portion 109, and to avoid the extension portion 113 being too long, which would affect the current transmission at the bottom 103 of the shell 101. Specifically, in this embodiment, the length of the extension portion 113 is D4, where 2mm≤D4≤3mm; more specifically, the length of the extension portion 113 can be 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, or 3.0mm.

[0039] In another embodiment, the battery 100 further includes a protective layer disposed below the bottom 103 of the housing 101 (the "bottom" herein refers to the second side 105, i.e., the protective layer covers the second side 105), and the orthographic projection of the protective layer on the bottom 103 of the housing 101 covers the orthographic projections of the plurality of first welds 109 on the bottom 103 of the housing 101. Specifically, the protective layer covers the plurality of first welds 109, isolating the plurality of first welds 109 from the outside world and protecting the first welds 109 from oxidation and corrosion.

[0040] 6 , the collecting plate 106 includes a core material 114 and an outer layer 115 located outside the core material 114 . The core material 114 is welded to the bottom 103 of the shell 101 through the outer layer 115 . The core material 114 includes copper, and the outer layer 115 includes nickel. It should be noted that in order to ensure the strength of the battery 100, the material of the shell 101 is generally steel, and the shell 101 and the current collecting plate 106 are connected by welding. In order to achieve the purpose of reducing resistance, the material of the current collecting plate 106 is selected as copper, but copper has poor reflectivity to laser welding, and the welding process is complicated and difficult. Therefore, the material of the core material 114 is selected as copper, and the material of the outer layer 115 is selected as nickel. The outer layer 115 is wrapped around the outside of the core material 114. On the one hand, the outer material is nickel, and nickel can reduce the reflection of laser welding. Plating a layer of nickel on the outside of copper can improve the machinability of copper, making the current collecting plate 106 easier to weld with the shell 101. At the same time, the outer layer 115 is wrapped around the outer layer 115 of the core material 114, which can protect the core material 114, prevent the core material 114 from being exposed to the air and being oxidized and corroded, and improve the service life of the current collecting plate 106.

[0041] It should be noted that in the actual process, not only the resistance of the collecting disc 106 needs to be considered, but also the strength of the collecting disc 106 itself and the size of the space occupied. If the collecting disc 106 is thin, the connection strength will be weak and the collecting disc 106 will be easy to break. If the collecting disc 106 is thicker, the space occupied by the collecting disc 106 will increase, resulting in an increase in the size of the entire battery 100. The thickness of the core material 114 is D5, and the thickness of the outer layer 115 is D6, where D5 ≥ 0.15 mm and 0.3 μm ≤ D6 ≤ 3.5 μm. Specifically, the thickness of the core material 114 can be 0.15, 0.18, 0.2, 0.25, 0.3, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm; the thickness of the outer layer 115 can be 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0 .8μm, 0.9μm, 1.0μm, 1.2μm, 1.4μm, 1.6μm, 1.8μm, 1.5μm, 2.0μm, 2.2μm, 2.4μm, 2.5μm, 2.6μm, 2.8μm, 2.9μm, 3.0μm, 3.1μm, 3.2μm, 3.3μm, 3.4μm, 3.5μm, select according to actual situation.

[0042] The embodiment of the present application further proposes a battery module 1000 , as shown in FIG7 . The battery module 1000 includes a plurality of batteries 100 and a connecting piece 200 . The connecting piece 200 is formed with a plurality of connecting portions 201 , and each connecting portion 201 is connected to a corresponding battery 100 .

[0043] Referring to Figures 5 and 7 , each battery cell 100 further includes a third welding portion 120 formed on the side of the bottom 103 of the housing 101 facing away from the current collecting plate 106 (i.e., multiple third welding portions 120 are formed on the second side 105 ). The battery cell 100 is welded to the connecting piece 200 via the third welding portion 120. It should be noted that the orthographic projection of the third welding portion 120 on the bottom 103 of the housing 101 does not overlap with the orthographic projection of the first welding portion 109 on the bottom 103 of the housing 101. This arrangement is intended to prevent interference between the first welding portion 109 and the third welding portion 120, which could result in welding difficulties. In one embodiment, the third welding portion 120 is located at the center of the bottom 103 of the housing 101.

[0044] More specifically, within the same battery 100, multiple first welding portions 109, multiple second welding portions 116 and third welding portions 120 are staggered in their orthographic projections on the collecting plate 106. There is no interference between the first welding portions 109, the second welding portions 116 and the third welding portions 120, making welding easier and the welding connection strength more stable.

[0045] It should be noted that an annular boss 118 is formed on the collecting plate 106 to prevent the shell 101 from interfering with the annular boss 118. The bottom 103 of the shell 101 is recessed away from the collecting plate 106 to form a weld accommodating portion 123. The weld accommodating portion 123 is used to avoid the annular boss 118 so that the weld accommodating portion 123 can accommodate multiple first welding portions 109.

[0046] An embodiment of the present application further provides a battery pack, including a box and a battery module 1000 , wherein the battery module 1000 is disposed in the box.

Claims

1. A battery comprising: A housing (101) having a top and a bottom (103), wherein a cavity (102) is formed in the housing (101); a collecting plate (106) disposed in the cavity (102); and A plurality of first welding portions (109) are formed on a side of the current collecting plate (106) close to the bottom (103); the current collecting plate (106) is welded to the bottom (103) via the plurality of first welding portions (109); the plurality of first welding portions (109) are arranged around the center of the current collecting plate (106); and the distance from each first welding portion (109) to the center of the current collecting plate (106) is greater than the distance from the first welding portion (109) to the edge of the current collecting plate (106).

2. The battery according to claim 1, wherein Each of the first welding portions (109) has a first side (110) close to the center of the current collecting plate (106) and a second side (111) away from the center of the current collecting plate (106); the radius of the current collecting plate (106) is D1; ​​the shortest distance between the first side (110) and the center of the current collecting plate (106) is D2; the inertial force applied to the current collecting plate (106) is F1; the welding force applied to the first welding portion (109) is F2; ​​the number of the first welding portions (109) is n, wherein F1 = D1 <nF2D2。 3. The battery according to claim 2, wherein The distance between the first side edge (110) and the second side edge (111) is D3, wherein 7.0 mm ≤ D2 ≤ 9.4 mm, and 0.1 mm ≤ D3 ≤ 0.3 mm.

4. The battery according to claim 1, wherein The distance between each two adjacent first welding portions (109) is the same; and / or, The first welding portion (109) is in the shape of an arc, a circular ring, a C-shape or a spiral.

5. The battery according to any one of claims 1 to 4, further comprising a shell (112), wherein the shell (112) is sleeved on the shell (101), and one end of the shell (112) close to the bottom (103) is folded inward to form an extension portion (113), wherein the extension portion (113) covers a portion of the bottom (103), and the orthographic projection of the extension portion (113) on the bottom (103) covers the orthographic projections of the plurality of first welding portions (109) on the bottom (103) of the shell (101). The battery according to claim 5 , further comprising an insulating film, wherein the insulating film is sleeved on the outer shell.

7. The battery according to claim 5, wherein The length of the extension portion (113) is D4, wherein 2.55 mm≤D4≤3.4 mm.

8. The battery according to any one of claims 1 to 4, further comprising a protective layer, wherein the protective layer is disposed below the bottom (103) of the shell (101), and the orthographic projection of the protective layer on the bottom (103) of the shell (101) covers the orthographic projections of the plurality of first welding portions (109) on the bottom (103) of the shell (101).

9. The battery according to any one of claims 1 to 4, wherein: The collecting plate (106) comprises a core material (114) and an outer layer (115) located outside the core material (114); the core material (114) is welded to the bottom (103) of the shell (101) through the outer layer (115); the material of the core material (114) comprises copper, and the material of the outer layer (115) comprises nickel.

10. The battery according to claim 9, wherein The thickness of the core material (114) is D5, and the thickness of the outer layer (115) is D6, wherein D5≥0.15 mm, and 0.3 μm≤D6≤3.5 μm.

11. The battery according to any one of claims 1 to 4, further comprising a winding core (122) and a plurality of second welding portions (116), wherein the plurality of second welding portions (116) are formed on a side of the current collecting plate (106) away from the bottom (103) of the shell (101), and the current collecting plate (106) is welded to the winding core (122) through the plurality of second welding portions (116), and the plurality of second welding portions (116) are arranged around the center of the current collecting plate (106), and each second welding portion (116) is arranged alternately with each first welding portion (109).

12. The battery according to claim 11, wherein The distance between any two adjacent second welding portions (116) is the same.

13. The battery according to claim 11, wherein The collecting plate (106) comprises a first connecting section (117) and a second connecting section (119) arranged around the first connecting section (117); the second connecting section (119) is recessed in a direction toward the bottom (103) of the shell (101) to form an annular boss (118); a plurality of the first welding portions (109) are formed under the annular boss (118); and a plurality of the second welding portions (116) are formed on the first connecting section (117).

14. The battery according to any one of claims 1 to 4, wherein: The bottom (103) of the shell (101) is recessed in a direction away from the collecting plate (106) to form a weld accommodating portion (123), and the weld accommodating portion (123) is used to accommodate a plurality of the first weld portions (109).

15. A battery module, comprising: A plurality of batteries, each of which is a battery as claimed in any one of claims 1 to 10; as well as, The connecting sheet (200) is formed with a plurality of connecting portions (201), and each connecting portion (201) is connected to a corresponding battery.

16. The battery module according to claim 15, wherein: Each of the batteries further comprises a third welding portion (120), wherein the third welding portion (120) is formed on a side of the bottom (103) away from the current collecting plate (106), and the battery is welded to the connecting sheet (200) via the third welding portion (120).

17. The battery module according to claim 16, wherein: The battery also includes a plurality of second welding portions (116); In the same battery, the orthographic projections of a plurality of the first welding portions (109), a plurality of the second welding portions (116), and the third welding portion (120) on the current collecting plate (106) are staggered.

18. A battery pack comprising: Box; as well as, The battery module (1000) according to any one of claims 15 to 17, wherein the battery module (1000) is arranged in the box.

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