Adapters, rechargeable batteries, and electronic devices

Abstract

An object of the present invention is to provide an adapter, a secondary battery, and an electronic device that at least improve the utilization efficiency of the space occupied by the adapter.SOLUTION: An embodiment of the present invention provides an adapter used for electrically connecting an electrode assembly and a terminal. The adapter includes a terminal fixing portion, an electrode assembly connecting portion provided to surround the terminal fixing portion, and a first transition portion connecting the terminal fixing portion and the electrode assembly connecting portion. The adapter has an electrode assembly connection side and a terminal connection side that are reversely distributed. Each of the first transition portion and the terminal fixing portion has a first surface and a first end surface located on a terminal connection side, and a second surface and a second end surface located on an electrode assembly connection side. The second surface protrudes in a direction away from the terminal connection side than the second end surface.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an adapter, 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 casing, a cover plate, and the like. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator between the positive electrode sheet and the negative electrode sheet. After these positive electrode sheet, negative electrode sheet, and separator are laminated together, they are wound to form the electrode assembly, and then it is installed in the casing.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In view of the problems in the related art, the present invention provides an adapter, a secondary battery, and an electronic device that can at least improve the utilization efficiency of the space occupied by the adapter.

Means for Solving the Problems

[0004] To achieve the above object, an embodiment of the present invention provides an adapter used for electrically connecting an electrode assembly and a terminal. The adapter includes a terminal fixing portion, an electrode assembly connection portion provided to surround the terminal fixing portion, and a first transition portion connecting between the terminal fixing portion and the electrode assembly connection portion. The adapter has an electrode assembly connection side and a terminal connection side that are distributed in the reverse direction (the reverse distribution means that one side of the adapter is the electrode assembly connection side, and the other side on the opposite side in the thickness direction is the terminal connection side). The first transition portion includes a first surface located on the terminal connection side and a second surface located on the electrode assembly connection side. The terminal fixing portion includes a first end face located on the terminal connection side and a second end face located on the electrode assembly connection side. The second surface protrudes in a direction away from the terminal connection side compared to the second end face.

[0005] In some embodiments, the first surface of the first transition portion protrudes away from the terminal. The adapter is integrally molded.

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

[0007] In some embodiments, the range of the second depth in which the second surface of the first transition portion protrudes away from the second end face toward the terminal connection side is 0.01 mm to 5 mm.

[0008] In some embodiments, the adapter further includes a second transition portion connecting a first transition portion and an electrode assembly connection portion. The second transition portion includes a third surface located on the terminal connection side and a fourth surface located on the electrode assembly connection side. The third surface protrudes away from the electrode assembly connection side and does not extend beyond the first end face.

[0009] In some embodiments, the terminal fixing portion has a frustoconical shape, and in an orthographic projection along the direction from the first end face to the second end face, the terminal fixing portion is two concentric circles, and / or the first transition portion is provided surrounding the terminal fixing portion.

[0010] Embodiments of the present invention further provide a secondary battery. The secondary battery includes an electrode assembly formed by sequentially stacking and winding a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator, and an adapter of any one of the embodiments described above. A terminal fixing portion is electrically connected to the terminals of the secondary battery, and an electrode assembly connection portion is electrically connected to a tab of the electrode assembly.

[0011] In some embodiments, the electrode assembly includes a central hole. At least a portion of the terminal fixing portion and / or the first transition portion is located within the central hole, or at least a portion of the orthogonal projection of the first transition portion is located within the central hole along the direction from the first end face to the second end face.

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

[0013] Embodiments of the present invention further provide an electronic device. The electronic device includes at least one of the adapters of any of the embodiments described above and a secondary battery of any of the embodiments described above. [Effects of the Invention]

[0014] The beneficial technical effects of this invention are as follows:

[0015] Embodiments of the present invention provide a first transition portion that protrudes away from the terminal connection side, thereby shortening the distance between the second end face of the terminal fixing portion of the adapter and the electrode assembly connection portion, reducing the distance between the electrode assembly and the terminal, reducing the height space that the adapter needs to occupy, and improving the utilization efficiency of the space occupied by the adapter.

[0016] In some embodiments of the present invention, lithium-ion batteries generate gas during the cycling and storage processes, causing the battery's volume to expand. After gas generation, internal pressure compresses the terminals. Furthermore, lithium-ion batteries easily cause stress concentration above and below the terminals under vibration conditions. By providing a first transition section, stress between the terminal fixing section and the electrode assembly connection section can be relieved, preventing poor welding between the tab and adapter from affecting battery performance. In addition, the first transition section can mitigate the transmission of terminal stress to the electrode assembly connection section. [Brief explanation of the drawing]

[0017] To more clearly illustrate embodiments of the present invention or technical solutions in the prior art, the accompanying drawings that may be used in the description of embodiments or prior art are briefly introduced below. The drawings described below represent only a few embodiments of the present invention, and it will be apparent to those skilled in the art that other embodiments can be derived from these drawings without expending any creative effort.

[0018] [Figure 1] Shows a schematic diagram when the electronic device according to an embodiment of the present invention is a vehicle. [Figure 2] Represents a perspective view of an embodiment in which a secondary battery according to an embodiment of the present invention is a cylindrical battery. [Figure 3] Represents a cross-sectional view of an embodiment in which a secondary battery according to an embodiment of the present invention is a cylindrical battery. [Figure 4] Represents an electrode assembly of an embodiment in which a secondary battery according to an embodiment of the present invention is a cylindrical battery. [Figure 5] Represents an enlarged view of region A where the adapter in FIG. 3 is located.

Embodiments for Carrying Out the Invention

[0019] For a better understanding of the spirit of the embodiments of the present invention, it will be further described below in combination with preferred embodiments of the present invention. [[ID=​​​​​​​​​In this specification, unless otherwise specified or limited, relative terms such as, for example, "central", "vertical", "horizontal", "front", "rear", "right", "left", "inner", "outer", "low", "high", "level", "vertical", "upper", "lower", "top", "bottom", and terms derived therefrom (e.g., "downward", "upward", etc.) should be construed as referring to the directions described in the description or illustrated in the accompanying drawings. These relative terms are used for convenience of description and do not require the present invention to be constructed or operated in a specific direction.

[0023] For convenience of description, "first", "second", "third", etc. may be used in this specification to distinguish different components in one figure or a series of figures. "First", "second", "third", etc. do not describe the corresponding components.

[0024] The present invention provides an electronic device 1000, which includes a battery pack 1002. The operating part of the electronic device 1000 obtains power support by being electrically connected to the battery pack 1002. As one example, the electronic device 1000 is a vehicle, which may be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be, but is not limited to, a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. The operating part is the vehicle body, and the battery pack 1002 is located at the bottom of the vehicle body and provides power support for the vehicle's operation or the operation of in-vehicle electrical components. However, in some other embodiments, the electronic device 1000 may be a mobile phone, a portable device, a notebook computer, a ship, an airplane, an electric toy, a power tool, etc. Aircraft include airplanes, rockets, space shuttles, spacecraft, etc. The operating part may be a unit member that acquires electrical energy from the battery pack 1002 and performs a corresponding operation, such as a fan blade rotation unit or a vacuum cleaner dust collection unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planes. Embodiments of the present invention are not particularly limited to the electronic devices 1000 described above.

[0025] For the sake of explanation, the following embodiments will be described using the example that the electronic device 1000 is a vehicle. Referring to Figure 1, a battery pack 1002 is provided inside the vehicle. The battery pack 1002 may be provided at the bottom, top, or rear of the vehicle body 1001. The battery pack 1002 may be used to supply power to the vehicle; for example, the battery pack 1002 may serve as the operating power source for the vehicle.

[0026] Figure 2 shows a perspective view of an embodiment of the secondary battery 100 according to an embodiment of the present invention, in which the secondary battery is a cylindrical battery. Figure 3 shows a cross-sectional view of an embodiment of the secondary battery 100 according to an embodiment of the present invention, in which the secondary battery is a cylindrical battery, and only the position of the adapter 150 is shown, and its specific shape is not shown. Figure 4 shows the electrode assembly 120 of an embodiment of the secondary battery 100 according to an embodiment of the present invention, in which the secondary battery is a cylindrical battery. Figure 5 shows an enlarged view of region A where the adapter 150 in Figure 3 is located. The secondary battery 100 includes a housing 110, an electrode assembly 120, terminals 140, terminal sealing nails 50, and a cover plate 130. The outside of the terminals 140 is joined to the adapter 150 by laser welding, and then the upper surface of the terminals 140 is welded and sealed using the terminal sealing nails 50. The housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. The connection between the end wall 111 and the side wall 112 may be achieved by any of several methods, such as integral stamping, integral casting, or segment welding, as long as a stable sealing and electrical connection relationship can be formed. The enclosure by the side wall 112 is not limited and may be cylindrical or prismatic, or it may be any other closed-loop contour that coincides with the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical and surrounds the outer edge of the end wall 111. A circular opening 113 is formed at one end of the side wall 112 opposite to the end wall 111. A housing cavity is formed within the housing 110 enclosed by the end wall 111 and the side wall 112, which is used to house the electrode assembly 120, the electrolyte, and other components necessary for the battery. Specifically, the diameter of the housing 110 may be determined by the specific size of the electrode assembly 120, for example, 18 mm, 21 mm, 46 mm, etc. The material of the housing 110 may be one of several types, such as copper, iron, aluminum, steel, or aluminum alloy. To prevent rust from forming on the housing 110 during long-term use, the surface of the housing 110 may be plated with a layer of rust-preventive material, such as metallic nickel.

[0027] The electrode assembly 120 is housed within the housing 110. The electrode assembly 120 is a component in which electrochemical reactions occur within the secondary battery 100. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 includes a wound structure formed by winding a positive electrode sheet 121, a first separator 131, a negative electrode sheet 123, and a second separator 132. Specifically, it includes a positive electrode sheet 121, a first separator 131, a negative electrode sheet 123, and a second separator 132 wound around the axial direction of the housing 110. The positive electrode sheet 121 includes a positive electrode current collector 1211 and a positive electrode active material layer coated on the positive electrode current collector 1211. On the positive electrode current collector 1211, a first coated region 1212 coated with a positive electrode active material layer and a first uncoated region 1213 not coated with a positive electrode active material layer are formed, and the first coated region 1212 and the first uncoated region 1213 are arranged along the axial direction of the housing 110. One end of the first uncoated region 1213 facing the height direction h of the secondary battery extends outward from the separator 122 and is folded toward the axis of the housing 110 to form a stacked positive electrode tab 125. The negative electrode sheet 123 includes a negative electrode current collector 1231 and a negative electrode active material layer coated on the negative electrode current collector 1231. On the negative electrode current collector 1231, a second coated region 1232 coated with a negative electrode active material layer and a second uncoated region 1233 not coated with a negative electrode active material layer are formed, and the second coated region 1232 and the second uncoated region 1233 are arranged along the axial direction of the housing 110. One end of the second uncoated region 1233 facing the height direction h of the secondary battery extends outward from the separator 122 and is folded toward the axis of the housing 110 to form a stacked negative electrode tab 124. The first separator 131 and the second separator 132 are provided between the positive electrode sheet 121 and the negative electrode sheet 123 to isolate the positive electrode active material layer and the negative electrode active material layer. Taking a lithium-ion cylindrical battery 100 as an example, the material of the positive electrode current collector 1211 may be aluminum, and the positive electrode active material layer contains a positive electrode active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The material of the negative electrode current collector 1231 may be copper, and the negative electrode active material layer contains a negative electrode active material, which may be carbon or silicon.The substrates of the first separator 131 and the second separator 132 may be PP (polypropylene) or PE (polyethylene), etc. To provide the cell with protective and insulating functions, the outside of the cell may be further covered with an insulating film, which may be synthesized from PP, PE, PET, PVC, or other polymer materials.

[0028] Furthermore, in this invention, the positive electrode tab 125 faces the end wall 111 or the opening 113, and 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 terminal 140, thereby positively charging the terminal. The negative electrode tab 124 faces the opening 113, and the housing 110 is electrically connected to the negative electrode tab 124, thereby negatively charging it. However, in other embodiments, the negative electrode tab 124 may be connected to the terminal 140 and the positive electrode tab 125 may be connected to the housing 110.

[0029] The cap plate 130 is installed to seal the opening 113. The outer edge shape of the cap plate 130 corresponds to the shape of the opening 113, and it seals the opening 113 by connecting to the side wall 112. The mounting method of the cap plate 130 may be mechanical sealing or welding sealing, but is not limited to these. In this embodiment, the cap plate 130 employs mechanical sealing to seal and close the opening 113.

[0030] In one example of the secondary battery 100 of the present invention, the electrode assembly 120 is provided sealed within the housing 110. Along the height direction h of the cylindrical battery 100, the electrode assembly 120 is provided between the end wall 111 and the roll groove 114, and the roll groove 114 can restrict the axial movement of the electrode assembly 120 between the end wall 111 and the roll groove 114.

[0031] Embodiments of the present invention improve upon embodiments in which the terminal fixing portion of the adapter and the electrode assembly connection portion have surfaces facing the electrode assembly that are substantially close to being on the same plane. The terminal fixing portion needs to be electrically connected to the terminal by being provided in a frustoconical shape. For this reason, in the above-described embodiment of the substantially close to being on the same plane, the height space occupied from the terminal-facing surface of the terminal fixing portion to the electrode assembly-facing surface of the electrode assembly connection portion is large, resulting in low space utilization efficiency.

[0032] Referring to Figure 5, an embodiment of the present invention provides an adapter 150 used for electrical connection between an electrode assembly 120 and a terminal 140. The adapter 150 includes a terminal fixing portion 10, an electrode assembly connection portion 20 provided surrounding the terminal fixing portion 10, and a first transition portion 22 connecting the terminal fixing portion 10 and the electrode assembly connection portion 20. The adapter 150 has an electrode assembly connection side and a terminal connection side distributed back-to-back. The first transition portion 22 includes a first surface 221 located on the terminal connection side and a second surface 222 located on the electrode assembly connection side. The terminal fixing portion 10 includes a first end face 101 located on the terminal connection side and a second end face 102 located on the electrode assembly connection side. The second surface 222 protrudes in a direction away from the terminal connection side than the second end face 102. Embodiments of the present invention provide a first transition portion 22 that protrudes away from the terminal connection side, thereby shortening the distance between the second end face 102 of the terminal fixing portion 10 of the adapter 150 and the electrode assembly connection portion 20, thereby reducing the distance between the electrode assembly 120 and the terminal 140, reducing the height space that the adapter 150 needs to occupy, and improving the utilization efficiency of the space occupied by the adapter 150. In some embodiments, the above-described shape of the adapter 150 may be formed by stamping, or by welding the adapter 150 in contact with the terminal 140.

[0033] In some embodiments of the present invention, gas is generated during the cycling and storage processes of the lithium-ion secondary battery 100, causing the battery's volume to expand. After gas generation, the internal pressure compresses the terminals 140. Furthermore, the lithium-ion cylindrical battery 100 easily causes stress concentration above and below the terminals 140 under vibration conditions. By providing the first transition section 22, the stress between the terminal fixing section 10 and the electrode assembly connection section 20 can be relieved, preventing poor welding between the tabs 124 / 125 and the adapter 150, which would affect battery performance. In addition, the first transition section 22 can mitigate the transmission of stress from the terminals 140 to the electrode assembly connection section 20.

[0034] In some embodiments, the first surface 221 of the first transition portion 22 protrudes away from the terminal 140. The adapter 150 is integrally molded. In other words, the first transition portion 22 having the aforementioned protrusion and recess is not a protrusion separately welded onto the adapter 150.

[0035] In some embodiments, the material of the adapter 150 is aluminum.

[0036] In some embodiments, the electrode assembly connection portion 20 includes a third end face 203 located on the terminal connection side and a fourth end face 204 also located on the electrode assembly connection side. The second end face 102 protrudes to a first depth in a direction away from the terminal connection side than the fourth end face 204, and the range of the first depth is 0.01 mm to 5 mm. That is, the range of the reduced distance between the first end face 101 and the fourth end face 204 (which reduces the height space) is 0.01 mm to 5 mm.

[0037] In some embodiments, the range of the second depth in which the second surface 222 of the first transition portion 22 protrudes away from the second end face 102 toward the terminal connection side is 0.01 mm to 5 mm. A depth value of 0.01 mm or more ensures that the first transition portion 22 protrudes beyond the electrode assembly connection portion 20. A depth value of 5 mm or less ensures that the protrusion depth is not excessively large, preventing the terminal fixing portion 10 from contacting the terminal 140.

[0038] In some embodiments, the adapter 150 further includes a second transition portion 24 connecting the first transition portion 22 and the electrode assembly connection portion 20. The second transition portion 24 includes a third surface 243 located on the terminal connection side and a fourth surface 244 located 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 similarly protrudes away from the electrode assembly connection side. By providing the second transition portion 24 that protrudes away from the electrode assembly connection side, the flatness of the electrode assembly connection portion is ensured as much as possible, and stress concentration is avoided. 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 terminal fixing portion 10 cannot contact the terminal 140, and a gap exists between the two, making it impossible to ensure welding strength.

[0039] In some embodiments, the terminal fixing portion 10 has a frustoconical shape, and in an orthographic projection from the first end face 101 to the second end face 102, i.e., along the direction toward the electrode assembly 120, the terminal fixing portion 10 is two concentric circles, and / or the first transition portion 22 is provided surrounding the terminal fixing portion 10. That is, the lateral size of the terminal fixing portion 10 decreases along the direction away from the electrode assembly 120. The terminal fixing portion 10 having a frustoconical shape can more accurately electrically connect to the terminal 140. The first transition portion 22 is a perfect circle.

[0040] Embodiments of the present invention further provide a secondary battery 100. The secondary battery 100 includes an electrode assembly 120 formed by sequentially stacking and winding a positive electrode sheet 121, a first separator 131, a negative electrode sheet 123, and a second separator 132, and an adapter 150 of any one of the embodiments described above. The terminal fixing portion 10 is electrically connected to the terminal 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 invention improves the space utilization efficiency of the secondary battery 100 by using an adapter 150 having a first transition portion 22.

[0041] In some embodiments, the electrode assembly 120 includes a central hole 160. The central hole 160 is located in the central region of the positive electrode sheet 121, the first separator 131, the negative electrode sheet 123, and the second separator 132, and at least a portion of the terminal fixing portion 10 and / or the first transition portion 22 is located within the central hole 160, or the orthographic projection of the first transition portion 22 is located at least partially within the central hole 160 along the direction from the first end face 101 to the second end face 102. In situations where the battery vibrates, the central hole 160 provides space to accommodate the first transition portion 22, thereby relieving stress and producing a desirable effect. The depth to which the terminal fixing portion 10 and / or the first transition portion 22 are recessed into the central hole 160 is, for example, 0.01 mm to 5 mm. When the terminal fixing portion 10 sinks into the central hole 160, the maximum depth of the sinking is equal to the depth to which its second end face 102 protrudes beyond the electrode assembly connection portion 20 into the electrode assembly 120. On the other hand, the central part of the electrode assembly 120 / bare cell is the central hole 160. That is, the central part is empty. Also, the innermost circle from the central hole 160 is a separator, and the number of electrode sheet (foil material) layers in the inner circle is less than in the outer circle. Referring to Figure 4, the number of layers of the positive electrode tab 125 and negative electrode tab 124 in the region close to the central hole 160 is small, so at least a part of the terminal fixing portion 10 and the first transition portion 22 is housed inside the electrode assembly 120, the height of the first end face 101 of the terminal fixing portion 10 relative to the electrode assembly 120 is reduced, and the space that the terminal fixing portion 10 needs to occupy in the secondary battery 100 is also reduced, thus increasing the space utilization efficiency of the secondary battery 100. Please understand that the number of layers in the positive electrode sheet 121 and the negative electrode sheet 123 is not limited to the number of layers shown in Figure 4, and the actual number of layers in the product may be, for example, 14 or more.

[0042] In some embodiments, the adapter 150 is a positive electrode adapter.

[0043] In some embodiments, the secondary battery 100 is a cylindrical battery. The ratio of the height (distance from the end wall 111 to the cap plate 130, as shown in Figure 3) to the diameter (outer diameter) of the cylindrical battery is in the range of 1.7 to 3.3. For example, the height is 80 mm and the diameter is 46 mm. In another example, the height is 15 mm and the diameter is 46 mm. In some embodiments, the cylindrical battery is a 4680 cylindrical battery. When the ratio of height to diameter is within the above range, the secondary battery 100 has a certain height, and in some processes, vibrations of the secondary battery 100 are transmitted in the height direction of the cylindrical battery. The adapter 150 relieves the corresponding stress, thereby improving the safety of the battery and avoiding welding defects between the positive electrode tab 125 and the adapter 150.

[0044] Embodiments of the present invention further provide a battery pack 1002 comprising an adapter 150 from any of the embodiments described above and at least one secondary battery 100 from any of the embodiments described above.

[0045] Embodiments of the present invention further provide an electronic device 1000 comprising an adapter 150 from any of the embodiments described above and at least one secondary battery 100 from any of the embodiments described above (and the battery pack 1002 described above).

[0046] The above description represents only preferred embodiments of the present invention and does not limit it. Those skilled in the art can make various modifications and changes to the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are equally covered by the protection of the present invention. [Industrial applicability]

[0047] The present invention, by providing a first transition section, can alleviate stress between the terminal fixing section and the electrode assembly connection section, thereby preventing poor welding between the tab and the adapter from affecting battery performance. Furthermore, the first transition section can reduce the transmission of stress from the terminal to the electrode assembly connection section. [Explanation of Symbols]

[0048] 10: Terminal fixing part 20: Electrode assembly connection part 22: First Transition Section 24: Second Transition Section 50: Terminal seal nails 100: Secondary battery 101: First end surface 102:Second end surface 110: Cabinet 111: End wall 112: Side wall 113:Aperture 114: Roll Groove 120: Electrode assembly 121: Positive electrode sheet 1211: Positive electrode current collector 1212: 1st application area 1213: 1st non-coating area 123: Negative electrode sheet 1231: Negative electrode current collector 1232:Second application area 1233: 2nd non-coating area 124: Tab 125: Tab 130: Cover plate 131: First Separator 132: Second Separator 140: Terminal 150: Adapter 160: Center hole 203: Third end surface 204: 4th end face 221: 1st surface 222: 2nd surface 243:Third surface 244: 4th surface 1000:Electronic equipment 1001: Vehicle body 1002: Battery Pack h: Height direction

Claims

1. An adapter used to electrically connect an electrode assembly and a terminal, Terminal fixing part, An electrode assembly connection portion is provided surrounding the terminal fixing portion, A first transition section connecting the terminal fixing section and the electrode assembly connection section, A second transition section connects the first transition section and the electrode assembly connection section. Includes, It has an electrode assembly connection side and a terminal connection side with electrodes distributed in opposite directions. The first transition portion includes a first surface located on the terminal connection side and a second surface located on the electrode assembly connection side. The terminal fixing portion includes a first end face located on the terminal connection side and a second end face located on the electrode assembly connection side. The second surface protrudes in a direction away from the terminal connection side than the second end face, The first surface of the first transition portion protrudes in a direction away from the terminal, The second transition portion includes a third surface located on the terminal connection side and a fourth surface located on the electrode assembly connection side. The third surface protrudes away from the electrode assembly connection side and does not exceed the first end face. Characterized by, adapter.

2. The adapter is integrally molded. Characterized by, The adapter according to claim 1.

3. The electrode assembly connection portion includes a third end face located on the terminal connection side and a fourth end face located on the electrode assembly connection side. The second end face protrudes to a first depth in a direction away from the terminal connection side than the fourth end face, and the range of the first depth is 0.01 mm to 5 mm. Characterized by, The adapter according to claim 1.

4. The range of the second depth in which the second surface of the first transition portion protrudes in a direction away from the terminal connection side than the second end face is 0.01 mm to 5 mm. Characterized by, The adapter according to claim 1.

5. The terminal fixing portion has a frustoconical shape, and in an orthographic projection along the direction from the first end face to the second end face, the terminal fixing portion is two concentric circles and / or, The first transition section is provided surrounding the terminal fixing section, and / or The material of the adapter is aluminum. Characterized by, The adapter according to claim 1.

6. An electrode assembly formed by sequentially stacking a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator, and then winding them together, The adapter according to any one of claims 1 to 5 and A secondary battery that includes, The terminal fixing portion is electrically connected to the terminals of the secondary battery, and the electrode assembly connecting portion is electrically connected to the tabs of the electrode assembly. Characterized by, Secondary battery.

7. The electrode assembly includes a central hole, At least a portion of the terminal fixing portion and / or the first transition portion is located within the central hole, Along the direction from the first end face to the second end face, at least a portion of the orthogonal projection of the first transition portion is located within the central hole. Characterized by, The secondary battery according to claim 6.

8. It is a cylindrical battery, The ratio of height to diameter is in the range of 1.7 to 3.

3. Characterized by, The secondary battery according to claim 6.

9. Includes the secondary battery described in claim 6 Characterized by, electronic equipment.

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