Adapter sheet, secondary battery, and electronic device

Abstract

The embodiment of the utility model provides an adapter plate, which is used for electrically connecting an electrode assembly and a pole, and comprises a pole fixing part and an electrode assembly connecting part arranged around the pole fixing part, the first transition part is connected between the pole fixing part and the electrode assembly connecting part, the switching piece is provided with an electrode assembly connecting side and a pole connecting side which are distributed back to back, and the first transition part and the pole fixing part respectively comprise a first surface and a first end face which are located on the pole connecting side and a second surface and a second end face which are located on the electrode assembly connecting side; the second surface protrudes in the direction away from the pole connecting side relative to the second end face. The utility model aims to provide an adapter piece, a secondary battery and an electronic device, so as to at least improve the utilization rate of the space occupied by the adapter piece.

Description

Technical Field

[0001] The utility model relates to an adapter plate, a secondary battery and an electronic device. Background Art

[0002] In the field of new energy power batteries, a secondary battery generally includes an electrode assembly, a housing, a cover plate, etc. The electrode assembly includes a positive electrode plate, a negative electrode plate and a separator located between the positive electrode plate and the negative electrode plate. These positive electrode plates, negative electrode plates and separators are stacked on top of each other and then wound into an electrode assembly, which is then encapsulated in a housing. Summary of the Utility Model

[0003] Aiming at the problems existing in the related art, the purpose of the utility model is to provide an adapter plate, a secondary battery and an electronic device, so as to at least improve the utilization rate of the space occupied by the adapter plate.

[0004] To achieve the above object, an embodiment of the present application provides an adapter plate for electrically connecting an electrode assembly and a terminal post, including: a terminal post fixing part and an electrode assembly connecting part arranged around the terminal post fixing part; a first transition part connected between the terminal post fixing part and the electrode assembly connecting part. The adapter plate has an electrode assembly connection side and a terminal post connection side distributed back to back (distributed back to back means that one side of the adapter plate is the electrode assembly connection side, and the other side in the opposite thickness direction is the terminal post connection side). The first transition part includes a first surface located on the terminal post connection side and a second surface located on the electrode assembly connection side. The terminal post fixing part includes a first end face and a second end face located on the terminal post connection side, and the second surface protrudes in a direction away from the terminal post connection side compared with the second end face.

[0005] In some embodiments, the first surface of the first transition part protrudes in a direction away from the terminal post; the adapter plate is integrally formed.

[0006] In some embodiments, the electrode assembly connecting part includes a third end face located on the terminal post connection side and a fourth end face located on the electrode assembly connection side. The second end face protrudes a first depth in a direction away from the terminal post connection side compared with the fourth end face, and the value range of the first depth is from 0.01 mm to 5 mm.

[0007] In some embodiments, the value range of the second depth that the second surface of the first transition part protrudes in a direction away from the terminal post connection side compared with the second end face is from 0.01 mm to 5 mm.

[0008] In some embodiments, the adapter plate further includes: a second transition part connected between the first transition part and the electrode assembly connecting part. The second transition part includes a third surface located on the terminal post connection side and a fourth surface located on the electrode assembly connection side. The third surface protrudes in a direction away from the electrode assembly connection side and does not exceed the first end face.

[0009] In some embodiments, the pole fixing portion has a frustum shape. When projected orthogonally in the direction from the first end face to the second end face, the pole fixing portion is two concentric circles, and / or, the first transition portion is disposed around the pole fixing portion.

[0010] An embodiment of the present application further provides a secondary battery, including: an electrode assembly formed by winding a positive electrode tab, a first separator, a negative electrode tab, and a second separator in sequence after being stacked layer by layer; a connection tab as described in any one of the above, where the pole fixing portion is electrically connected to the pole of the secondary battery, and the electrode assembly connection portion is electrically connected to the tab of the electrode assembly.

[0011] In some embodiments, the electrode assembly includes a central hole, and at least a part of the pole fixing portion and / or the first transition portion is located in the central hole, or, when projected orthogonally in the direction from the first end face to the second end face, at least a part of the projection of the first transition portion is located in the central hole.

[0012] In some embodiments, the secondary battery is a cylindrical battery, and the ratio of the height to the diameter of the cylindrical battery ranges from 1.7 to 3.3.

[0013] An embodiment of the present application further provides an electronic device, including at least one of the connection tab as described in any one of the above and the secondary battery as described in any one of the above.

[0014] The beneficial technical effects of the present utility model are as follows:

[0015] By providing the first transition portion protruding away from the pole connection side in the embodiments of the present application, the distance between the second end face of the pole fixing portion of the connection tab and the electrode assembly connection portion is reduced, thereby reducing the distance between the electrode assembly and the pole, reducing the height space occupied by the connection tab, and improving the utilization rate of the space occupied by the connection tab.

[0016] In some embodiments of the present application, during the cycling and storage of lithium-ion batteries, gas is generated, causing the battery volume to expand. After gas generation, the pole is extruded due to the internal pressure. Additionally, in the vibration condition of lithium-ion batteries, stress concentration is extremely likely to occur at the upper and lower parts of the pole. By providing the first transition portion, the stress between the pole fixing portion and the electrode assembly connection portion can be relieved, avoiding the welding failure between the tab and the connection tab, which affects the battery performance, and also relieving the pole stress from being transmitted to the electrode assembly connection portion through the first transition region. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 A schematic diagram showing a case where the electronic device according to an embodiment of the present application is a vehicle.

[0019] Figure 2 A perspective view of an embodiment in which a secondary battery according to an embodiment of the present application is a cylindrical battery is shown.

[0020] Figure 3 A cross-sectional view of an embodiment in which the secondary battery according to the embodiment of the present application is a cylindrical battery is shown.

[0021] Figure 4 The electrode assembly is shown when the secondary battery according to the embodiment of the present application is an embodiment of a cylindrical battery.

[0022] Figure 5 Shows Figure 3 A magnified view of area A where the transfer patch is located. DETAILED DESCRIPTION

[0023] In order to better understand the spirit of the embodiments of the present application, some preferred embodiments of the present application are further described below.

[0024] The embodiments of the present application will be described in detail below. In the full text of the present application specification, the same or similar components and components with the same or similar functions are represented by similar reference numerals. The embodiments of the accompanying drawings described herein are illustrative, graphical, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as limiting the present application.

[0025] As used herein, the terms "substantially," "substantially," "essentially," and "about" are used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred precisely as well as instances where the event or circumstance occurred very approximately.

[0026] In this specification, unless otherwise specified or limited, relative terms such as "central", "longitudinal", "lateral", "front", "rear", "right", "left", "inner", "outer", "lower", "higher", "horizontal", "vertical", "above", "below", "above", "below", "top", "bottom" and their derivative terms (such as "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the directions described in the discussion or depicted in the drawings. These relative terms are only used for convenience of description and do not require that the present application be constructed or operated in a specific direction.

[0027] For ease of description, "first", "second", "third", etc. may be used herein to distinguish different components of a figure or a series of figures. "First", "second", "third", etc. are not intended to describe the corresponding components.

[0028] The present utility model provides an electronic device 1000, and the electronic device 1000 includes a battery pack 10. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain power support. As an example, the electronic device 1000 is a vehicle, and the vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc., but is not limited thereto. The working part is the vehicle body, and the battery pack 1002 is arranged at the bottom of the vehicle body and provides power support for the running of the vehicle or the operation of electrical components in the vehicle. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the working part can obtain the electric energy of the battery pack 1002 and is a unit component that performs corresponding work, such as the fan blade rotation unit of a fan, the dust suction working unit of a vacuum cleaner, etc. The electric toy includes a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, for example, an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator, an electric planer, etc. The embodiments of the present application do not impose special restrictions on the above-mentioned electronic device 1000.

[0029] For the convenience of description in the following embodiments, the electronic device 1000 is taken as an example of a vehicle. Refer to Figure 1 , a battery pack 1002 is arranged inside the vehicle, and the battery pack 1002 can be arranged at the bottom, head, or tail of the vehicle body 1001. The battery pack 1002 can be used for power supply of the vehicle. For example, the battery pack 1002 can be used as the operating power source of the vehicle.

[0030] Figure 2 The perspective view of the embodiment shows that the secondary battery 100 according to the embodiment of the present application is a cylindrical battery. Figure 3 The cross-sectional view of the embodiment shows that the secondary battery 100 according to the embodiment of the present application is a cylindrical battery. Only the position of the connecting piece 150 is shown, and its specific shape is not shown. Figure 4 The electrode assembly 120 of the embodiment shows that the secondary battery 100 according to the embodiment of the present application is a cylindrical battery. Figure 5 The illustration shows Figure 3An enlarged view of the area A where the intermediate connection piece 150 is located. The secondary battery 100 includes a housing 110, an electrode assembly 120, a terminal 140, and a cover plate 130. The housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection relationship can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in various ways. For example, it can be integrally stamped, integrally cast, or separately welded. The surrounding of the side wall 112 is not limited. It can surround in a cylindrical or prismatic shape, or it can surround along any other closed-loop contour that can match the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 surrounds the outer edge of the end wall 111 in a cylindrical shape, and a circular opening 113 is formed at one end of the side wall 112 facing away from the end wall 111. An accommodation cavity is formed inside the housing 110 surrounded by the end wall 111 and the side wall 112, which is used to accommodate the electrode assembly 120, the electrolyte, and other necessary battery components. Specifically, the diameter size of the housing 110 can be determined according to the specific size of the electrode assembly 120, such as 18 mm, 21 mm, 46 mm, etc. The material of the housing 110 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the housing 110 from rusting during long-term use, an anti-rust material such as metal nickel can also be plated on the surface of the housing 110.

[0031] The electrode assembly 120 is accommodated in the housing 110. The electrode assembly 120 is a component in the secondary battery 100 where an electrochemical reaction occurs. One or more electrode assemblies 120 may be included in the housing 110. The electrode assembly 120 includes a positive electrode tab 121, a first separator 131, a negative electrode tab 123, and a second separator 132, which are wound to form a wound structure. Specifically, in this embodiment, the electrode assembly 120 includes a positive electrode tab 121, a first separator 131, a negative electrode tab 123, and a second separator 132 that are wound around the axis of the housing 110. The positive electrode tab 121 includes a positive current collector 1211 and a positive active material layer coated on the positive current collector 1211. A first coated area 1212 coated with the positive active material layer and a first uncoated area 1213 not coated with the positive active material layer are formed on the positive current collector 1211. The first coated area 1212 and the first uncoated area 1213 are arranged along the axis of the housing 110. The first uncoated area 1213 extends to the outside of the separator 122 at one end in the height direction h of the secondary battery 100 and bends towards the axis of the housing 110 to form a stacked positive electrode ear 125. The negative electrode tab 123 includes a negative current collector 1231 and a negative active material layer coated on the negative current collector 1231. A second coated area 1232 coated with the negative active material layer and a second uncoated area 1233 not coated with the negative active material layer are formed on the negative current collector 1231. The second coated area 1232 and the second uncoated area 1233 are arranged along the axis of the housing 110. The second uncoated area 1233 extends to the outside of the separator 122 at the other end in the height direction h of the secondary battery 100 and bends towards the axis of the housing 110 to form a stacked negative electrode ear 124. The first separator 131 and the second separator 132 are disposed between the positive electrode tab 121 and the negative electrode tab 123 to isolate the positive active material layer and the negative active material layer. Taking the lithium-ion cylindrical battery 100 as an example, the material of the positive current collector 1211 may be aluminum, and the positive active material layer includes a positive active material, which may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, etc. The material of the negative current collector 1231 may be copper, and the negative active material layer includes a negative active material, which may be carbon or silicon, etc. The base material of the first separator 131 and the second separator 132 may be PP (polypropylene) or PE (polyethylene), etc. To protect and insulate the battery cell, an insulating film may also be coated on the outside of the battery cell, and the insulating film may be synthesized from PP, PE, PET, PVC, or other polymer materials.

[0032] Further, in the present utility model, if the positive electrode tab 125 faces the end wall 111 or the opening 113, then the negative electrode tab 124 faces the other end of the housing 110. In this embodiment, the positive electrode tab 125 faces the end wall 111 and is electrically connected to the pole column 140 to make the pole column 140 positively charged, and the negative electrode tab 124 faces the opening 113, and the housing 110 is electrically connected to the negative electrode tab 124, thereby being negatively charged. However, in other embodiments, the negative electrode tab 124 can also be connected to the pole column 140, and the positive electrode tab 125 can be connected to the housing 110.

[0033] The cover plate 130 is sealingly installed on the opening 113; the outer edge shape of the cover plate 130 corresponds to the shape of the opening 113 and is connected to the side wall 112 to seal the opening 113. The installation method of the cover plate 130 includes but is not limited to mechanical seal or welding seal. In this embodiment, the cover plate 130 is sealingly plugged on the opening 113 by mechanical seal.

[0034] In an example of the secondary battery 100 of the present utility model, the electrode assembly 120 is sealingly installed in the housing 110. Along the height direction h of the cylindrical battery 100, the electrode assembly 120 is disposed between the end wall 111 and the rolling groove 114, and the rolling groove 114 can limit the axial movement of the electrode assembly 120 between the end wall 111 and the rolling groove 114.

[0035] The embodiment of the present application is improved based on the embodiment in which the surfaces of the pole column fixing part and the electrode assembly connecting part of the adapter plate facing the electrode assembly are approximately flush. The pole column fixing part needs to be set in a frustum shape to be electrically connected to the pole column. Therefore, the height space occupied by the adapter plate in the above-mentioned approximately flush embodiment from the surface of the pole column fixing part facing the pole column to the surface of the electrode assembly connecting part facing the electrode assembly is relatively large, and the space utilization rate is low.

[0036] See Figure 5, embodiments of the present application provide an adapter piece 150 for electrically connecting an electrode assembly 120 and a terminal post 140, including: a terminal post fixing portion 10 and an electrode assembly connecting portion 20 disposed around the terminal post fixing portion 10; a first transition portion 22 connected between the terminal post fixing portion 10 and the electrode assembly connecting portion 20. The adapter piece 150 has a back-to-back distributed electrode assembly connection side and a terminal post connection side. The first transition portion 22 includes a first surface 221 on the terminal post connection side and a second surface 222 on the electrode assembly connection side. The terminal post fixing portion 10 includes a first end face 101 on the terminal post connection side and a second end face 102 on the electrode assembly connection side. The second surface 222 protrudes away from the terminal post connection side compared to the second end face 102. By providing the first transition region 22 that protrudes away from the terminal post connection side, embodiments of the present application reduce the distance between the second end face 102 of the terminal post fixing portion 10 of the adapter piece 150 and the electrode assembly connecting portion 20, thereby reducing the distance between the electrode assembly 120 and the terminal post 140, reducing the height space occupied by the adapter piece 150, and improving the utilization rate of the space occupied by the adapter piece 150. In some embodiments, the above shape of the adapter piece 150 can be formed by stamping, or formed when the adapter piece 150 is abutted against the terminal post 140 for welding.

[0037] In some embodiments of the present application, during the cycling and storage of the lithium-ion secondary battery 100, gas is generated, causing the battery volume to expand. After the gas is generated, the terminal post 140 is extruded due to the internal pressure. In addition, in the vibration condition of the lithium-ion cylindrical battery 100, stress concentration is extremely likely to occur at the upper and lower parts of the terminal post 140. By providing the first transition region 22, the stress between the terminal post fixing region 10 and the electrode assembly connecting portion 20 can be relieved, avoiding the welding failure between the electrode tabs 124 / 125 and the adapter piece 150, which affects the battery performance, and the stress of the terminal post 140 can also be relieved from being transmitted to the electrode assembly connecting portion 20 through the first transition region 22.

[0038] In some embodiments, the first surface 221 of the first transition portion 22 protrudes away from the terminal post 140; the adapter piece 150 is integrally formed, that is, the first transition region 22 with the above protrusions and depressions is not an additional protrusion welded to the adapter piece 150.

[0039] In some embodiments, the electrode assembly connecting portion 20 includes a third end face 203 on the terminal post connection side and a fourth end face 204 on the electrode assembly connection side. The second end face 102 protrudes away from the terminal post connection side compared to the fourth end face 204 by a first depth, and the value range of the first depth is from 0.01 mm to 5 mm. That is, the reduced distance (and thus the reduced height space) between the first end face 101 and the fourth end face 204 ranges from 0.01 mm to 5 mm.

[0040] In some embodiments, the value range of the second depth at which the second surface 222 of the first transition portion 22 protrudes away from the pole connection side compared to the second end face 102 is from 0.01 mm to 5 mm. The value of the depth is greater than or equal to 0.01 mm to ensure that the first transition portion 22 protrudes compared to the electrode assembly connection portion 20, and the value of the depth is less than or equal to 5 mm to ensure that the protruding depth is not too large so that the pole fixing portion 10 cannot contact the pole 140.

[0041] In some embodiments, the adapter piece 150 further includes: a second transition portion 24 connected between the first transition region 22 and the tab welding region 20. The second transition portion 24 includes a third surface 243 on the pole connection side and a fourth surface 244 on the electrode assembly connection side. The third surface 243 protrudes away from the electrode assembly connection side and does not exceed the first end face 101. The fourth surface 244 of the second transition portion 24 also protrudes away from the electrode assembly connection side. The second transition portion 24 that protrudes away from the electrode assembly connection side is provided to ensure the flatness of the electrode assembly connection portion as much as possible and avoid stress concentration. On the other hand, if the third surface 243 of the second transition portion 24 exceeds the first end face 101, the first end face 101 of the pole fixing portion 10 cannot contact the pole 50, and there is a gap between the two, so that the welding strength cannot be guaranteed.

[0042] In some embodiments, the pole fixing portion 10 has a frustum shape. When projected orthogonally in the direction from the first end face 101 to the second end face 102, that is, in the direction toward the electrode assembly 120, the pole fixing portion 10 is two concentric circles, and / or the first transition portion 22 is disposed around the pole fixing portion 10. That is to say, the lateral dimension of the pole fixing portion 10 decreases in the direction away from the electrode assembly 120. The pole fixing portion 10 having a frustum shape can be more accurately electrically connected to the pole 140. The first transition portion 22 is a complete circle.

[0043] An embodiment of the present application further provides a secondary battery 100, including: an electrode assembly 120, which is formed by winding a positive electrode plate 121, a first separator 131, a negative electrode plate 123, and a second separator 132 in sequence; the adapter piece 150 of any one of the above, the pole fixing portion 10 is electrically connected to the pole 140 of the secondary battery 100, and the electrode assembly connection portion 20 is electrically connected to the tab of the electrode assembly 120. The secondary battery 100 of the embodiment of the present application uses the adapter piece 150 having the first transition portion 22 to improve the space utilization rate of the secondary battery 100.

[0044] In some embodiments, the electrode assembly 120 includes a central hole 160, which is a region located at the center of the positive electrode tab 121, the first separator 131, the negative electrode tab 123, and the second separator 132. At least a portion of the pole fixing portion 10 and / or the first transition portion 22 is located within the central hole 130. Alternatively, along the direction from the first end face 101 to the second end face 102, at least a portion of the orthographic projection of the first transition portion 22 is located within the central hole 160. Under working conditions such as battery vibration, the central hole 130 provides a space for accommodating the first transition portion 22, which can relieve stress and has a good effect. The depth of the pole fixing portion 10 and / or the first transition portion 22 indented into the central hole 130 is, for example, from 0.01 mm to 5 mm. When the pole fixing portion 10 is indented into the central hole 130, the maximum depth of indentation is equal to the depth by which its second end face 102 protrudes toward the electrode assembly 120 compared to the electrode assembly connection portion 20. On the one hand, at the center of the electrode assembly / naked battery cell JR 120 is the central hole 125, that is, the center is empty. On the other hand, the innermost circle starting from the central hole 125 is the separator, and the number of layers of the tabs (foils) at the inner circle is lower than that of the outer circle. Refer to Figure 4 , in the region near the central hole 125, the number of layers of the positive electrode tab 125 and the negative electrode tab 124 is small. Therefore, at least a portion of the pole fixing portion 10 and the first transition portion 22 can be accommodated inside the electrode assembly 120, reducing the height of the first end face 101 of the pole fixing portion 10 relative to the electrode assembly 120 and also reducing the space occupied by the pole fixing portion 10 in the secondary battery 100. Thus, the space utilization rate of the secondary battery 100 is improved. It should be understood that the number of layers of the positive electrode tab 121 and the negative electrode tab 123 is not limited to Figure 4 as shown, and the number of layers of the actual product is, for example, more than 14 layers.

[0045] In some embodiments, the adapter plate 150 is a positive adapter plate.

[0046] In some embodiments, the secondary battery 100 is a cylindrical battery, and the ratio of the height (as Figure 3 shown, the distance from the end wall 111 to the cover plate 130) to the diameter (outer diameter) of the cylindrical battery ranges from 1.7 to 3.3. For example, the height is 80 mm and the diameter is 46 mm; or for another example, the height is 15 mm and the diameter is 46 mm. In some embodiments, the cylindrical battery is a 4680 cylindrical battery.

[0047] An embodiment of the present application further provides a battery pack 1002, including at least one of the adapter plate 150 of any one of the above and the secondary battery 100 of any one of the above.

[0048] An embodiment of the present application further provides an electronic device 1000, including at least one of the adapter plate 150 of any one of the above and the secondary battery 100 (and the battery pack 1002) of any one of the above.

[0049] The foregoing is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. For those skilled in the art, the present utility model may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A transition piece for electrically connecting an electrode assembly and a terminal post, characterized in that, Comprising: A pole fixing part and an electrode assembly connecting part disposed around the pole fixing part; A first transition part connected between the pole fixing part and the electrode assembly connecting part. The adapter plate has an electrode assembly connection side and a pole connection side distributed back to back. The first transition part includes a first surface on the pole connection side and a second surface on the electrode assembly connection side. The pole fixing part includes a first end face on the pole connection side and a second end face on the electrode assembly connection side. The second surface protrudes in a direction away from the pole connection side compared to the second end face.

2. The adapter sheet according to claim 1, wherein The first surface of the first transition part protrudes in a direction away from the pole. The adapter plate is integrally formed.

3. The adapter plate according to claim 1, wherein The electrode assembly connecting part includes a third end face on the pole connection side and a fourth end face on the electrode assembly connection side. The second end face protrudes from the fourth end face in a direction away from the pole connection side by a first depth, and the value range of the first depth is 0.01 mm to 5 mm.

4. The adapter sheet according to claim 1, wherein The value range of the second depth by which the second surface of the first transition part protrudes in a direction away from the pole connection side compared to the second end face is 0.01 mm to 5 mm.

5. The adapter sheet according to claim 2, wherein Further comprising: A second transition part connected between the first transition part and the electrode assembly connecting part. The second transition part includes a third surface on the pole connection side and a fourth surface on the electrode assembly connection side. The third surface protrudes in a direction away from the electrode assembly connection side and does not exceed the first end face.

6. The adapter sheet according to claim 1, wherein The pole fixing part has a frustum shape. When projected orthogonally in the direction from the first end face to the second end face, the pole fixing part is two concentric circles, and / or The first transition part is disposed around the pole fixing part.

7. A secondary battery, characterized in that, Comprising: An electrode assembly, which is formed by winding a positive electrode plate, a first separator, a negative electrode plate, and a second separator stacked in sequence; The adapter plate according to any one of claims 1 to 6, wherein the pole fixing part is electrically connected to the pole of the secondary battery, and the electrode assembly connecting part is electrically connected to the tab of the electrode assembly.

8. The secondary battery according to claim 7, wherein The electrode assembly includes a central hole; At least part of the pole fixing part and / or the first transition part is located within the central hole, or When projected orthogonally in the direction from the first end face to the second end face, at least part of the projection of the first transition part is located within the central hole.

9. The secondary battery according to claim 7, characterized in that, The secondary battery is a cylindrical battery, and the value range of the ratio of the height to the diameter of the cylindrical battery is 1.7 - 3.

3.

10. An electronic device, characterized in that, Including the secondary battery according to any one of claims 7 to 9.

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