Top cover assembly, energy storage device and electric equipment

Abstract

The utility model provides a top cover assembly, an energy storage device and electric equipment. The top cover assembly comprises a top cover, lower plastic, a pole and a collector plate. The top cover comprises a first side and a second side which are opposite in the thickness direction and is provided with a first through hole, and the first through hole penetrates through the first side of the top cover and the second side of the top cover. The lower plastic is arranged on the second side of the top cover, and a second through hole is formed in the lower plastic. The pole comprises a pole body and a pole ring, the pole body penetrates through the first through hole and the second through hole and comprises a first end and a second end which are opposite, the first end protrudes relative to the first side of the top cover and is provided with a first end face away from the second end, the first end face is provided with a groove sunken towards the second end, and the second end extends out of the second through hole in the direction away from the top cover. The pole ring is fixed on the peripheral wall of the second end, and the second end is provided with a second end face opposite to the bottom face of the groove. The collector plate is welded and connected with the second end face of the pole body, the grooves meet the relational expression that P is larger than or equal to 0.14 and smaller than or equal to 0.49, P is equal to h / D, h is the depth of the grooves, and D is the minimum width or the minimum diameter of the grooves in a plane perpendicular to the depth direction of the grooves.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a top cover assembly, an energy storage device, and an electrical device. Background Technology

[0002] Energy storage devices, such as battery cells, are widely used as the main power source for electrical equipment due to their recyclability. In current battery cells, the current collector and terminals in the top cover assembly are usually installed into an aluminum casing first, and then the two are connected together by welding. However, although this method of installing the casing first and then welding does not affect the installation of the top cover assembly into the casing, it is prone to connection defects (welding defects) between the current collector and the terminals, thereby preventing the battery cell from charging and discharging normally. Summary of the Invention

[0003] In view of the above problems, this application provides a top cover assembly, an energy storage device, and an electrical device.

[0004] In a first aspect, this application provides a top cover assembly. The top cover assembly includes a top cover, a lower plastic component, an electrode post, and a collector plate. The top cover includes a first side and a second side opposite to each other in the thickness direction, and is provided with a first through hole, the first through hole penetrating the first side and the second side of the top cover. The lower plastic component is disposed on the second side of the top cover, and the lower plastic component is provided with a through second through hole. The electrode post includes an electrode post body and an electrode post ring, the electrode post body passing through the first through hole and the second through hole, and includes a first end and a second end opposite to each other. The first end protrudes relative to the first side of the top cover and has a first end face away from the second end. The first end face is provided with a groove recessed toward the second end. The second end extends from the second through hole in a direction away from the top cover. The electrode post ring is fixed to the outer peripheral wall of the second end, and the second end has a second end face opposite to the bottom surface of the groove. The collector plate is welded to the second end face of the pole piece. The groove satisfies the following relationship: 0.14≤P≤0.49, P=h / D, where h is the depth of the groove and D is the minimum width or minimum diameter of the groove in the plane perpendicular to the depth direction of the groove.

[0005] In the top cover assembly of the above technical solution, if P is less than 0.14, the groove depth is usually made relatively small, resulting in a thick bottom and making welding prone to instability. Conversely, if P is greater than 0.49, the groove depth is larger than the minimum width or diameter, resulting in a long, narrow groove. The shielding gas used during welding cannot cover the welding area, leading to welding defects such as weld cracks and spalls. Therefore, a ratio P between the groove depth and the minimum width or diameter of the groove that is greater than or equal to 0.14 and less than or equal to 0.49 ensures that there are no connection defects (welding defects) between the terminal post and the current collector, allowing them to be firmly connected and ensuring normal charging and discharging of the battery cells.

[0006] As an optional technical solution in this application, 0.20≤P≤0.40. In the above technical solution, 0.20≤P≤0.40 can better ensure that there are no connection defects between the pole and the collector, and that the two can be firmly connected together.

[0007] As an optional technical solution of this application, the collector plate is a non-bending collector plate, and the bottom of the groove is connected to the collector plate by through welding; or, the bottom surface of the groove has an annular weld mark.

[0008] In the above technical solution, since the bottom of the groove is connected to the current collector by through welding, or a ring-shaped weld mark is formed on the bottom surface of the groove, the current collector does not need to be a bent type; that is, a non-bent type current collector is used. During the installation of the top cover assembly, since there is no need to consider the accuracy of the bending position, it is only necessary to ensure that the top cover and the housing do not scratch or collide, avoiding the generation of metal wires or deformation, ensuring the stability of the housing welding, and the welding stability of the non-bent current collector between the current collector and the terminal post. At the same time, the entire housing assembly method is simplified, reducing the number of processes, improving production efficiency, facilitating high-speed production of individual battery cells, and reducing the cost of individual battery cells. Furthermore, the assembly precision of the assembly equipment used when installing the top cover assembly does not require high precision, further reducing production costs.

[0009] As an optional technical solution of this application, the collector plate has a connection area to be connected to the second end face, and the area of ​​the connection area is greater than or equal to the area of ​​the bottom surface of the groove.

[0010] In the above technical solution, the area to be connected is greater than or equal to the area of ​​the bottom surface of the groove. The center of the collector plate does not need to be precisely aligned with the center of the pole post. This also ensures that the weld mark formed by the penetration weld will not exceed the area to be connected, such as entering the U-shaped area, which would cause the problem of poor welding or affect the welding of the tab and the collector plate.

[0011] As an optional technical solution of this application, the thickness T1 of the bottom of the groove and the thickness T2 of the collector plate satisfy the relationship: 0.50≤T1 / T2≤0.80.

[0012] In the above technical solution, the ratio between the bottom thickness T1 of the groove and the thickness T2 of the collector plate is greater than or equal to 0.50 and less than or equal to 0.80. On the one hand, the bottom thickness of the groove is moderate, and the bottom of the groove can be penetrated without increasing the laser power, thus avoiding the lower collector plate being welded through. On the other hand, the welding strength between the bottom of the groove and the collector plate can be guaranteed, greatly reducing the risk of cracking in the welding area.

[0013] As an optional technical solution of this application, the thickness T1 of the bottom of the groove satisfies the relationship: 0.30mm≤T1≤0.60mm. In this way, the thickness of the bottom of the groove is moderate, and the laser power can penetrate the bottom of the groove without increasing it, thus avoiding the lower collector plate being welded through. On the other hand, the welding strength between the bottom of the groove and the collector plate can be guaranteed, greatly reducing the risk of cracking in the welding area.

[0014] As an optional technical solution of this application, the thickness T2 of the current collector plate satisfies the relationship: 0.15≤T2≤0.48. Thus, the current-carrying capacity and strength of the current collector plate meet the requirements.

[0015] As an optional technical solution of this application, the first end of the pole piece is provided with a protrusion; the top cover assembly further includes an upper plastic and a sealing element. The upper plastic is sleeved on the pole piece and includes a first sub-part and a second sub-part that are in contact. The first sub-part is disposed on the first side of the top cover, and at least a portion of the first sub-part is sandwiched between the top cover and the protrusion in the thickness direction of the top cover. The second sub-part passes through the first through hole and the second through hole, and forms a receiving cavity with the inner wall of the second through hole. The sealing element surrounds the second sub-part and is received in the receiving cavity. In the thickness direction of the top cover, the sealing element is sandwiched between the top cover and the pole piece ring.

[0016] In the above technical solution, the top plastic has good insulation properties, which can prevent internal short circuits in the battery cell and improve the safety of the battery cell. The sealant can provide a good sealing effect, preventing electrolyte leakage from inside the battery cell, and also preventing external moisture and impurities from entering the battery cell.

[0017] As an optional technical solution of this application, the electrode ring is welded to the outer peripheral wall of the second end of the electrode body. Welding the electrode ring to the outer peripheral wall of the second end of the electrode body allows for control of the compression of the seal, ensuring that the compression of the seal is within a suitable range, guaranteeing the sealing effect of the seal, and thus ensuring the safety of the battery cell.

[0018] As an optional technical solution in this application, the material of the electrode ring is the same as the material of the second end of the electrode body. This ensures the overall current transmission capability of the electrode, thereby guaranteeing its overcurrent capacity.

[0019] Secondly, this application provides an energy storage device. The energy storage device includes the top cover assembly described in any of the above embodiments.

[0020] In the energy storage device of the above technical solution, the ratio P between the depth of the groove in the top cover assembly and the minimum width or minimum diameter of the groove is greater than or equal to 0.14 and less than or equal to 0.49, which can ensure that there will be no connection defects between the pole and the current collector, and that the two can be firmly connected together to ensure that the battery cells can be charged and discharged normally.

[0021] Thirdly, this application provides an electrical appliance. The electrical appliance includes the energy storage device described in any of the above embodiments.

[0022] In the electrical equipment of the above technical solution, the ratio P between the depth of the groove in the top cover assembly and the minimum width or minimum diameter of the groove is greater than or equal to 0.14 and less than or equal to 0.49, which can ensure that there will be no connection defects between the terminal post and the current collector, and that the two can be firmly connected together to ensure that the battery cell can be charged and discharged normally.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0025] Figure 1 This is a three-dimensional assembly diagram of the top cover assembly according to some embodiments of this application;

[0026] Figure 2 for Figure 1 An exploded perspective view of the top cover assembly shown.

[0027] Figure 3 for Figure 1 An exploded perspective view of the top cover assembly shown below;

[0028] Figure 4 for Figure 1 A top view of the top cover assembly shown;

[0029] Figure 5 for Figure 4 The diagram shows a cross-sectional view of the top cover assembly along line VV.

[0030] Figure 6 for Figure 5 Enlarged view of point VI in the middle;

[0031] Figure 7 for Figure 6 Schematic diagrams of different implementations of the central groove;

[0032] Figure 8 for Figure 6 A schematic diagram illustrating the principle of connecting the bottom of the central groove to the collector plate via through-welding.

[0033] Figure 9 This is a three-dimensional structural diagram of a battery cell according to some embodiments of this application;

[0034] Figure 10 This is a three-dimensional structural diagram of a battery pack according to some embodiments of this application;

[0035] Figure 11 This is a schematic diagram of the planar structure of an electrical device according to some embodiments of this application.

[0036] The reference numerals in the detailed embodiments are as follows:

[0037] 10,000 electrical devices; 1,000 battery packs; 100 individual battery cells; 2,000 and 3,000 loads; 4,000 conversion devices; 10 top cover assemblies;

[0038] Top cover 11; First through hole 110; First side of top cover 111; Second side of top cover 113; First explosion-proof hole 115;

[0039] Lower plastic 12; second through hole 120; inner wall 1201; first side of lower plastic 121; second side of lower plastic 123; second explosion-proof hole 125;

[0040] 13 pole post; 131 pole post body; 1311 first end; 1312 first end face; 1313 second end; 1314 second end face; 1315 outer peripheral wall; 1310 groove; 1316 bottom surface; 1317 solder mark; 133 pole post ring; 135 protrusion;

[0041] Collector disk 14;

[0042] 15mm plastic top; 155mm perforation; 151mm first sub-section; 153mm second sub-section; 150mm receiving cavity;

[0043] 16. Seal; 17. Explosion-proof valve; 30. Housing; 300. Battery box; 310. Box body; 330. Thickness direction Z. Detailed Implementation

[0044] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0047] In this document, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations. It will be explicitly and implicitly understood by those skilled in the art that the implementations described herein can be combined with other implementations.

[0048] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, the simultaneous existence of mounting protrusions and mounting holes, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0049] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0050] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "level", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0051] In the description of the embodiments of this application, unless otherwise explicitly specified and limited, the technical terms such as "installation", "connection", "linking", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components.

[0052] Please refer to the following: Figure 1 To and Figure 3 This application provides a top cover assembly 10 in a first aspect. The top cover assembly 10 includes a top cover 11, a lower plastic part 12, an electrode post 13, and a collector plate 14. The top cover 11 includes a first side 111 and a second side 113 opposite to each other in the thickness direction Z, and is provided with a first through hole 110, which penetrates the first side 111 and the second side 113 of the top cover. The lower plastic part 12 is disposed on the second side 113 of the top cover, and is provided with a through second through hole 120. The electrode post 13 includes an electrode post body 131 and an electrode post ring 133. The electrode post body 131 passes through the first through hole 110 and the second through hole 120, and includes a first end 1311 and a second end 1313 opposite to each other. The first end 1311 protrudes from the first side 111 of the top cover and has a first end face 1312 away from the second end 1313, and the first end face 1312 is provided with a groove 1310 recessed toward the second end 1313. The second end 1313 extends from the second through hole 120 in a direction away from the top cover 11. The pole ring 133 is fixed to the outer peripheral wall 1315 of the second end 1313, and the second end 1313 has a second end face 1314 opposite to the bottom surface 1316 of the groove 1310. The collector plate 14 is welded to the second end face 1314 of the pole body 131. The groove 1310 satisfies the relationship: 0.14≤P≤0.49, P=h / D, where h is the depth of the groove 1310, and D is the minimum width or minimum diameter of the groove 1310 in the plane perpendicular to the depth direction of the groove 1310.

[0053] Please combine Figure 9The top cover assembly 10 is a component that covers the top opening of the housing 30 of the battery cell 100, providing a sealed space for the electrode assembly and electrolyte located inside the housing 30, and the electrical energy of the electrode assembly can be led out to the outside through the top cover assembly 10.

[0054] Please refer to the following: Figure 2 and Figure 3 The top cover 11 refers to a component that covers the opening of the housing 30 to isolate the internal environment of the battery cell 100 from the external environment. Indiscriminately, the shape of the top cover 11 can be adapted to the shape of the opening of the housing 30 to fit the housing 30. Specifically, the shape of the cross-section of the top cover 11 (the plane intercepted by a plane perpendicular to the thickness direction Z) can be determined according to the shape of the opening of the housing 30; that is, the cross-sectional shape of the top cover 11 can be circular, square, polygonal, or other shapes. For example, if the opening is circular, the corresponding cross-sectional shape of the top cover 11 can be circular; if the opening is rectangular, the corresponding cross-sectional shape of the top cover 11 can be rectangular. In this application, a top cover 11 with a circular cross-sectional shape is used for description, and the diameter direction of the top cover 11 is radial. Optionally, the top cover 11 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the top cover 11 is less prone to deformation under pressure and impact, enabling the battery cell 100 to have higher structural strength and higher safety performance. The first side 111 of the top cover faces the outside of the housing 30, and the second side 113 of the top cover faces the inside of the housing 30. The thickness direction Z of the top cover 11 refers to the direction in which the first side 111 of the top cover points to the second side 113 of the top cover, or vice versa. The thickness direction Z of the top cover 11 is also the height direction of the battery cell 100. The top cover 11 has a first through hole 110 that extends through the first side 111 and the second side 113 of the top cover along the thickness direction Z. In some embodiments, the projection of the first through hole 110 is located within the projection of the top cover 11 in a projection plane perpendicular to the thickness direction Z. Exemplarily, the center of the first through hole 110 coincides with the center of the top cover 11.

[0055] The lower plastic 12 is a component in the top cover assembly 10 that provides insulation. The lower plastic 12 is made of an insulating material, including but not limited to polypropylene, polyethylene, polyvinylidene fluoride, or polycarbonate. The lower plastic 12 is disposed on the second side 113 of the top cover. The lower plastic 12 includes a first side 121 and a second side 123 opposite to each other in the thickness direction Z. The first side 121 of the lower plastic faces the outside of the housing 30, and the second side 123 faces the inside of the housing 30. Therefore, the first side 121 of the lower plastic is opposite to the second side 113 of the top cover, and the second through hole 120 penetrates both the first side 121 and the second side 123 of the lower plastic. The lower plastic 12 has good insulation properties, which can prevent internal short circuits in the battery cell 100 and improve the safety of the battery cell 100.

[0056] The terminal 13 is a functional component used to conduct current from the electrode assembly to the external circuit of the battery cell 100 to output electrical energy from the electrode assembly, and to introduce electrical energy from outside the battery cell 100 into the electrode assembly. The terminal 13 passes through the top cover 11 from inside the battery cell 100 and extends to the outside of the top cover 11. The terminal 13 can be a positive terminal 13 or a negative terminal 13.

[0057] Please combine Figures 4 to 6 In some embodiments, the electrode post 13 includes a connected electrode body 131 and an electrode ring 133. The electrode body 131 passes through a first through hole 110 and a second through hole 120, and includes a first end 1311 and a second end 1313 opposite to each other. The first end 1311 protrudes from a first side 111 opposite to the top cover and has a first end face 1312 away from the second end 1313, the first end face 1312 having a groove 1310 recessed toward the second end 1313. The second end 1313 extends from the second through hole 120 in a direction away from the top cover 11, and has a bottom surface 1316 ( ) of the groove 1310 ( ). Figure 5 The pole ring 133 is fixed to the outer peripheral wall 1315 of the second end face 1314 (as shown).

[0058] It should be noted that the depth of the groove 1310 is the depth along the thickness direction Z of the top cover 11. In the plane perpendicular to the depth direction of the groove 1310, the shape of the groove 1310's outline can be circular, elliptical, square, or other irregular shapes. When the shape of the groove 1310's outline is circular, D is the diameter of the groove 1310; when the shape of the groove 1310's outline is elliptical, square, or other irregular shapes, D is the minimum width of the groove 1310. Furthermore, the opening size of the groove 1310 can be the same everywhere along the thickness direction Z of the top cover 11, such as... Figure 7 As shown in (a), the opening size of the groove 1310 may not be the same everywhere, including but not limited to Figure 7 (b) shows the top larger than the bottom. Figure 7 (c) shows the top smaller and bottom larger, and Figure 7 (d) shows the three implementation methods: first keeping it unchanged, then increasing it, and then decreasing it and then keeping it unchanged. When the opening size of the groove 1310 is not the same everywhere in the thickness direction Z of the top cover 11, D is the minimum value of the width of the groove 1310, or the minimum value of the diameter of the groove 1310. Figure 7 (b) The groove 1310 shown has a value of D2. Figure 7 (c) shows that the groove 1310 has a value of D3. Figure 7 (d) shows that the groove 1310 has a D of D4.

[0059] The groove 1310 satisfies the relationship: 0.14 ≤ P ≤ 0.49, P = h / D, that is, the ratio P between the depth of the groove 1310 and the minimum width or minimum diameter of the groove 1310 is greater than or equal to 0.14 and less than or equal to 0.49. For example, P can be 0.14, 0.15, 0.21, 0.25, 0.35, 0.37, 0.41, 0.43, 0.48, or 0.49, etc. Due to the current requirements of the battery cell 100, the minimum width or diameter of the groove 1310 has certain requirements. If P is less than 0.14, the depth of the groove 1310 will be relatively small compared to its minimum width or diameter, resulting in a thick bottom and making it difficult to securely connect to the current collector 14. Conversely, if P is greater than 0.49, the depth of the groove 1310 will be larger than its minimum width or diameter, resulting in a long and thin groove that cannot be properly covered by the shielding gas used during welding. This can lead to welding defects such as weld cracks and spalls (explained in detail below). Therefore, 0.14 ≤ P ≤ 0.49 ensures that there are no connection defects between the terminal post 13 and the current collector 14, allowing them to be firmly connected. Furthermore, 0.20≤P≤0.40, thus ensuring that there will be no connection defects between the pole post 13 and the collector plate 14, and that the two can be firmly connected together.

[0060] Please see Figure 2 Furthermore, in some embodiments, the pole post 13 may also include a protrusion 135, which is fixed to the outer peripheral wall 1315 of the first end 1311. In this case, both the protrusion 135 and the pole post ring 133 protrude radially outward relative to the pole post 131. In the thickness direction Z, the protrusion 135 protrudes from the first side 111 of the top cover, and the pole post ring 133 protrudes from the second side 113 of the top cover.

[0061] Both the bump 135 and the terminal ring 133 are annular components used for electrical connection. Both the bump 135 and the terminal ring 133 can be circular, square, or other irregularly shaped ring structures. It should be noted that in this application, "irregularly shaped" refers to a shape that is different from traditional regular shapes, such as circles, ellipses, squares (including rectangles and squares), isosceles triangles, equilateral triangles, regular pentagons, or regular hexagons. For example, an "irregularly shaped" shape can be an irregular pentagon, an irregular hexagon, or an irregular heptagon.

[0062] The electrode post 131 and the electrode ring 133 can be two independent single structures, which are then connected together by a specific fixing method. Correspondingly, the electrode post 131 and the protrusion 135 can also be two independent single structures, which are then connected together by a specific fixing method; of course, the electrode post 131 and the protrusion 135 can also be made of the same raw material and formed into two interconnected parts by stamping or cold forging processes. Thus, an electrode post 13 with protruding ends and a concave middle is formed.

[0063] The current collector 14 is a functional component used to electrically connect the electrode assembly and the terminal 13 inside the battery cell 100, so as to conduct the current in the electrode assembly to the outside of the battery cell 100 or to introduce external current into the battery cell 100. Typically, the current collector 14 is made of a conductive material to facilitate current conduction. The current collector 14 can be made of metals such as aluminum or copper, or other conductive materials such as aluminum alloys or copper alloys. The current collector 14 includes a positive current collector 14 and a negative current collector 14. The positive current collector 14 is used to electrically connect the positive terminal 13 and the tab of the electrode assembly, and the negative current collector 14 is used to electrically connect the negative terminal 13 and the tab of the negative electrode assembly.

[0064] The external circuit of the battery cell 100 is typically made of aluminum to reduce cost and weight. Therefore, the connection between the external circuit and the battery cell 100 generally uses aluminum sheets. In one embodiment, inside the battery cell 100, the positive current collector 14 is made of aluminum foil, and the negative current collector 14 is made of copper foil. Therefore, the positive electrode post 13 must be made of aluminum and the negative electrode post 13 of copper to ensure the performance of the battery cell 100. Based on this requirement, the positive electrode post 13 can be made entirely of aluminum. The negative electrode post 13 can be a composite post 13 formed of copper and aluminum, with the copper portion of the negative electrode post 13 closer to the side where the current collector 14 is located to ensure conductivity with the current collector 14, while the aluminum portion of the negative electrode post 13 is closer to the side away from the current collector 14. Aluminum is cheaper than copper, and the copper-aluminum composite negative electrode post 13 has a lower cost.

[0065] In the above technical solution, the ratio P between the depth of the groove 1310 and the minimum width or minimum diameter of the groove 1310 is greater than or equal to 0.14 and less than or equal to 0.49, which can ensure that there will be no connection defects between the pole post 13 and the current collector 14, and that the two can be firmly connected together, ensuring that the battery cell 100 can be charged and discharged normally.

[0066] As mentioned earlier, the collector plate 14 is connected to the second end face 1314 of the electrode post 131 by welding. For details, please refer to... Figure 5 and Figure 6 As an optional technical solution of this application, the collector plate 14 is a non-bending collector plate 14, and the bottom of the groove 1310 is connected to the collector plate 14 by through welding; or, the bottom surface 1316 of the groove 1310 has an annular weld mark 1317.

[0067] The collector plate 14 includes a bent collector plate and a non-bent collector plate. The bent collector plate includes at least one bend, and its extension direction lies across multiple planes, such as an S-shape. The non-bent collector plate does not contain a bend, and its extension direction lies across a single plane, such as... Figure 2 or Figure 3 As shown, the extension direction of the non-bending manifold is located within a circular disk surface. Penetration welding is a welding method that fuses the upper and lower components together by allowing laser energy to penetrate them. In this application, laser energy penetrates the bottom of the upper groove 1310 and the lower manifold 14, welding the bottom of the groove 1310 to the manifold 14. During penetration welding, the laser beam is focused within a very small area, forming a highly concentrated heat source region, melting the welded area and forming a strong weld point and weld seam; that is, an annular weld mark 1317 is formed on the bottom surface 1316 of the groove 1310.

[0068] When the top cover assembly 10 is installed in the housing, the non-bending current collector can be welded to the electrode assembly (core) first. Specifically, the tabs of the electrode assembly are welded to the three U-shaped areas of the current collector 14. Figure 2As shown), the electrode assembly (core) with the welded collector plate 14 is then inserted into the housing 30. Next, the top cover assembly 10 is aligned with the opening of the housing 30 and the second end face 1314 of the collector plate 14 and the top cover assembly 10 are pressed together by tightening the electrode assembly (core). Then, the top cover 11 is welded to the housing 30. Finally, the bottom of the groove 1310 is welded to the non-bent collector plate 14 by using a through welding process, thus completing the process of inserting the top cover assembly 10 into the housing. At this time, the current is transmitted from the inside of the battery cell 100 to the outside in the following order: the current of the electrode assembly is transmitted to the current collector 14 through the tab, the current collector 14 is transmitted to the terminal 13 from the second end face 1314, and the terminal 13 (terminal body 131 and terminal ring 133 mentioned below) is transmitted to the external circuit through the bump 135 or the first end 1311 of the terminal body 131 to realize the discharge of the battery cell 100 to the outside; the current is transmitted from the outside of the battery cell 100 to the inside in the following order: the current of the external circuit is transmitted to the second end 1313 of the terminal body 131 through the bump 135 or the first end 1311 of the terminal body 131, and the current of the second end 1313 of the terminal body 131 and / or the terminal ring 133 mentioned below is transmitted to the tab through the current collector 14, thereby reaching the electrode assembly to realize the charging of the battery cell 100.

[0069] When the top cover assembly uses a bent manifold, the manifold must be bent at least once (e.g., twice) before the top cover assembly can be inserted into the housing for cover welding. The positions of the first and second bends are relatively fixed to ensure the coaxiality of the top cover and the manifold after bending. If the positions of the first and second bends of the manifold are inaccurate, it will cause the top cover to be difficult to insert into the housing or the edge steps of the top cover to rub severely against the housing, producing metal wires or deforming the housing, affecting the cover welding.

[0070] In the above technical solution, since the bottom of the groove 1310 is connected to the current collector 14 by through welding, or the bottom surface 1316 of the groove 1310 has an annular weld mark 1317, the current collector 14 does not need to be a bent current collector; that is, the current collector 14 is a non-bent current collector. During the installation of the top cover assembly 10 into the casing, since there is no need to consider the accuracy of the bending position, it is only necessary to ensure that the top cover 11 and the casing 30 do not scratch or collide, avoiding the generation of metal wires or deformation, ensuring the stability of the casing welding, and the welding stability of the non-bent current collector 14 with the terminal post 13. At the same time, the entire casing assembly method is simplified, reducing the number of processes, improving production efficiency, facilitating high-speed production of the battery cell 100, and reducing the cost of the battery cell 100; furthermore, the assembly precision of the assembly equipment used when installing the top cover assembly 10 into the casing does not require high precision, reducing production costs.

[0071] On the other hand, the non-bending current collector 14 and the top cover assembly 10 are welded together, so the current collector 14 will not be pulled or compressed when the electrode assembly vibrates. Since the current collector 14 is attached to the second end face 1314 of the pole post 13 of the top cover assembly 10, and the core is interference-fitted along the axial direction (thickness direction Z), when the battery cell 100 with the non-bending current collector 14 vibrates, the current collector 14 will not vibrate with the electrode assembly (like a spring repeatedly compressed and released) as the battery cell 100 with the bending current collector 14 does. Therefore, the current collector 14 is not easy to break, ensuring that the battery cell 100 can always charge and discharge normally.

[0072] On the other hand, the bottom of the groove 1310 is connected to the manifold 14 by through-welding; that is, the groove 1310 is designed to facilitate the through-welding process. Therefore, it is necessary to consider how to design the specific structure of the groove 1310 to ensure that there are no welding defects (including but not limited to weld cracks or spalls) after the bottom of the groove 1310 is welded to the manifold 14. For details, please refer to [link to relevant documentation]. Figure 8 When performing a penetration welding process, a shielding gas (usually an inert gas) needs to be blown into the welding position. However, due to the presence of the groove 1310, the shielding gas may not be able to completely cover the welding area at the bottom of the groove 1310 (the area where the weld mark 1317 will be formed at the bottom of the groove 1310, which is usually annular). Therefore, the depth and width / diameter of the groove 1310 directly affect the welding effect. Figure 7 (a) where h represents the depth of groove 1310, D represents the minimum width / minimum diameter of groove 1310, x represents the outer diameter of the welding area, σ represents the outer diameter fluctuation tolerance of the welding area, L represents the gap between the welding area and the edge of groove 1310, and α represents the laser incident angle. The verification results of gradient samples of different specifications were calculated according to the following formula (as shown in Table 1):

[0073] The ratio of groove depth h to groove minimum width / diameter D: P = h / D (1)

[0074] D=x+σ+2L (2)

[0075] L=h / tan(90°-α) (3)

[0076]

[0077] The laser incident angle is determined by the assembly equipment. The outer diameter x of the welding area is determined by the current requirement of the battery cell 100 (current = cross-sectional area of ​​solder 1317 × copper / aluminum current coefficient). The fluctuation tolerance of the outer diameter of the solder area is generally ±0.5mm. After determining the design depth h of the groove 1310, the minimum width or minimum diameter of the groove 1310 can be determined. Thus, the following table 1 can be obtained. When performing the gradient sample verification in Table 1, the depth h of the groove 1310 is the gradient value set by the experimenter. L is calculated by formula (3), D is calculated by formula (2), and finally P is calculated by formula (1) or (4). At this time, the value of P can correspond to the experimental results, and the reasonable range of P values ​​can be determined. After determining the range of P values, when designing the product, the value of P can be determined first, h can be determined by formula (5), L can be determined by formula (3), and D can be determined by formula (2). In this way, the main dimensions of the groove 1310 can be determined.

[0078] Table 1

[0079]

[0080]

[0081] As shown in Table 1 above, when 0.14 ≤ P ≤ 0.49, no welding defects such as cracks or spalling occurred in the welded area. However, when the P value was above 0.55, problems such as cracking and spalling of the weld mark 1317 were observed. Therefore, when designing the depth of groove 1310 and the minimum diameter or minimum width of groove 1310, the ratio between the two can be controlled between 0.2 and 0.4 to reduce the risk of welding abnormalities. Figure 8 As shown, the flat groove 1310 is more conducive to the protective gas covering the entire welding area than the elongated groove 1310, thus reducing welding defects.

[0082] Please see Figure 6 As an optional technical solution of this application, the collector plate 14 has a connection area to be connected to the second end face 1314, and the area of ​​the connection area is greater than or equal to the area of ​​the bottom surface 1316 of the groove 1310.

[0083] Please combine Figure 2 The "area to be connected" refers to the area on the surface of the collector plate 14 facing the top cover 11, excluding the area to be welded to the electrode tab (U-shaped area). The area of ​​the area to be connected is greater than or equal to the area of ​​the bottom surface 1316 of the groove 1310. The center of the collector plate 14 does not need to be precisely aligned with the center of the electrode post 13. This ensures that the weld mark 1317 formed by the penetration weld will not exceed the area to be connected, such as entering the U-shaped area, which could lead to a problem of incomplete welding or affect the welding between the electrode tab and the collector plate 14.

[0084] Please see Figure 6 As an optional technical solution of this application, the thickness T1 of the bottom of the groove 1310 and the thickness T2 of the collector plate 14 satisfy the relationship: 0.50≤T1 / T2≤0.80. That is, the ratio between the thickness T1 of the bottom of the groove 1310 and the thickness T2 of the collector plate 14 is greater than or equal to 0.50 and less than or equal to 0.80. Specifically, the ratio between the thickness T1 of the bottom of the groove 1310 and the thickness T2 of the collector plate 14 can be 0.50, 0.51, 0.57, 0.61, 0.68, 0.70, 0.71, 0.73, 0.79, or 0.80. During penetration welding, the thickness of the upper component (bottom of groove 1310) should be less than the thickness of the lower component (collector plate 14). If the ratio between the thickness T1 of the bottom of groove 1310 and the thickness T2 of collector plate 14 is greater than 0.80, the upper component is too thick, requiring increased laser power to penetrate it during welding, which may cause the lower component to be welded through. If the ratio between the thickness T1 of the bottom of groove 1310 and the thickness T2 of collector plate 14 is less than 0.50, the upper component is too thin, which will reduce the welding strength and increase the risk of cracking in the welding area. Therefore, the ratio between the bottom thickness T1 of the groove 1310 and the thickness T2 of the collector plate 14 is greater than or equal to 0.50 and less than or equal to 0.80. On the one hand, the bottom thickness of the groove 1310 is moderate, and the laser power can penetrate the bottom of the groove 1310 without increasing it, thus preventing the lower collector plate 14 from being welded through. On the other hand, the welding strength between the bottom of the groove 1310 and the collector plate 14 can be guaranteed, greatly reducing the risk of cracking in the welding area.

[0085] Specifically, in some embodiments, the thickness T1 of the bottom of the groove 1310 satisfies the relationship: 0.30mm ≤ T1 ≤ 0.60mm. For example, the thickness T1 of the bottom of the groove 1310 is 0.30mm, 0.33mm, 0.38mm, 0.41mm, 0.45mm, 0.47mm, 0.50mm, 0.51mm, 0.57mm, or 0.60mm. In this way, the thickness of the bottom of the groove 1310 is moderate, and the laser power can penetrate the bottom of the groove 1310 without increasing it, thus preventing the lower collector plate 14 from being welded through. On the other hand, the welding strength between the bottom of the groove 1310 and the collector plate 14 can be guaranteed, greatly reducing the risk of cracking in the welding area.

[0086] Furthermore, in some embodiments, the thickness T2 of the manifold 14 satisfies the relationship: 0.15 ≤ T2 ≤ 0.48. For example, the thickness T2 of the manifold 14 is 0.15 mm, 0.18 mm, 0.20 mm, 0.24 mm, 0.29 mm, 0.30 mm, 0.33 mm, 0.38 mm, 0.41 mm, 0.45 mm, 0.47 mm, or 0.48 mm. In this way, the current carrying capacity and strength of the manifold 14 can meet the requirements.

[0087] Of course, in other embodiments, the thickness T1 of the bottom of the groove 1310 satisfies the relationship: 0.30mm≤T1≤0.60mm, and the thickness T2 of the collector plate 14 satisfies the relationship: 0.15≤T2≤0.48. Therefore, on the one hand, the thickness of the bottom of the groove 1310 is moderate, and the laser power can penetrate the bottom of the groove 1310 without increasing it, thus preventing the lower collector plate 14 from being welded through; on the other hand, the welding strength between the bottom of the groove 1310 and the collector plate 14 can be guaranteed, greatly reducing the risk of cracking in the welding area; furthermore, the current carrying capacity and strength of the collector plate 14 meet the requirements.

[0088] Please see Figure 6 As an optional technical solution of this application, the first end 1311 of the pole piece 131 is provided with a protrusion 135; the top cover assembly 10 also includes an upper plastic 15 and a sealing member 16. The upper plastic 15 is sleeved on the pole piece 131 and includes a first sub-part 151 and a second sub-part 153 that are in contact. The first sub-part 151 is disposed on the first side 111 of the top cover, and at least a portion of the first sub-part 151 is sandwiched between the top cover 11 and the protrusion 135 in the thickness direction Z of the top cover 11. The second sub-part 153 passes through the first through hole 110 and the second through hole 120, and forms a receiving cavity 150 between itself and the inner wall 1201 of the second through hole 120. The sealing member 16 surrounds the second sub-part 153 and is received in the receiving cavity 150. In the thickness direction Z of the top cover 11, the sealing member 16 is sandwiched between the top cover 11 and the pole piece ring 133.

[0089] The upper plastic 15 is a component in the top cover assembly 10 that provides insulation. The upper plastic 15 is made of an insulating material, including but not limited to polypropylene, polyethylene, polyvinylidene fluoride, or polycarbonate. The upper plastic 15 has good insulation properties, preventing internal short circuits in the battery cell 100 and improving the safety of the battery cell 100. Furthermore, the upper plastic 15 and the lower plastic 12 are both components in the top cover assembly 10 that provide insulation, but they can be made of the same insulating material or different insulating materials. The upper plastic 15 is disposed on the first side 111 of the top cover and sandwiched between the top cover 11 and the protrusion 135. That is, the upper plastic 15 is used to support the protrusion 135. In some embodiments, the upper plastic 15 includes two contiguous parts, a first sub-part 151 and a second sub-part 153, with the first sub-part 151 disposed on the first side 111 of the top cover. In addition, the upper plastic 15 has a through hole 155 that passes through the first sub-part 151 and the second sub-part 153, and the pole post 13 also passes through the through hole 155.

[0090] To prevent electrolyte leakage inside the battery cell 100, the top cover assembly 10 is also provided with a seal 16, which surrounds the second sub-part 153 and is housed in the receiving cavity 150. In the thickness direction Z of the top cover 11, the seal 16 is sandwiched between the top cover 11 and the terminal ring 133. Therefore, the seal 16 provides a good sealing effect, preventing electrolyte leakage inside the battery cell 100, and also preventing external moisture and impurities from entering the battery cell 100.

[0091] Please see Figure 6 The terminal ring 133 is welded to the outer peripheral wall 1315 of the second end 1313 of the terminal body 131, thus forming a complete weld mark at the mating position of the terminal ring 133 and the terminal body 131. Welding the terminal ring 133 to the outer peripheral wall 1315 of the second end 1313 of the terminal body 131 allows for control of the compression of the seal 16, ensuring that the compression of the seal 16 is within a suitable range, guaranteeing the sealing effect of the seal 16, and thus ensuring the safety of the battery cell 100 in use.

[0092] Furthermore, in some embodiments, the material of the terminal ring 133 is the same as the material of the second end 1313 of the terminal body 131. When the terminal 13 is a positive terminal 13, the material of the second end 1313 of the terminal body 131 is aluminum, and therefore the material of the terminal ring 133 is aluminum. When the terminal 13 is a negative terminal 13, the material of the second end 1313 of the terminal body 131 is copper-aluminum, and therefore the material of the terminal ring 133 is copper. The fact that the material of the terminal ring 133 is the same as the material of the second end 1313 of the terminal body 131 ensures the overall current carrying capacity of the terminal 13, thereby ensuring the overcurrent capacity of the terminal 13.

[0093] Furthermore, the top cover 11 is also provided with a first explosion-proof hole 115, which is a through hole penetrating the first side 111 and the second side 113 of the top cover, and is spaced apart from the first through hole 110. The lower plastic 12 is also provided with a second explosion-proof hole 125, which is a through hole penetrating the first side 121 and the second side 123 of the lower plastic, and is spaced apart from the second through hole 120, and corresponds to and communicates with the first explosion-proof hole 115. Furthermore, the top cover assembly 10 also includes an explosion-proof valve 16, which is installed in the first explosion-proof hole 115. When the internal chemical system of the battery cell 100 reacts abnormally and the internal environment begins to accumulate reaction gas, the explosion-proof valve 16 will burst open to release internal pressure when the gas pressure accumulates to the threshold of the explosion-proof valve 16, thereby ensuring the safety of battery use.

[0094] Please see Figure 9 and Figure 10 The second aspect of this application provides an energy storage device. The energy storage device includes the top cover assembly 10 of any of the above embodiments.

[0095] Specifically, the energy storage device can be a single battery cell 100 or a battery pack 1000 composed of one or more battery cells 100. The functions of the energy storage device include, but are not limited to, energy storage, energy dispatch, and energy storage power stations. Specifically, in some applications, the energy storage device can convert electrical energy into chemical energy for storage to meet electricity demand during peak periods, thus fulfilling the function of energy storage. In other applications, the energy storage device can flexibly adjust the supply and demand of electrical energy to achieve energy balance and dispatch, improving energy utilization efficiency, thus fulfilling the function of energy dispatch. In still other applications, energy storage devices can form energy storage power stations to store and dispatch energy on a large scale, providing a reliable energy supply, thus fulfilling the function of energy storage power stations.

[0096] Please see Figure 10When the energy storage device is a battery pack 1000 composed of multiple battery cells 100, the battery pack 1000 includes battery cells 100 and a battery box 300. A battery cell 100 is the smallest unit for storing and releasing electrical energy. The battery pack 1000 can store and release energy by connecting and controlling the battery cells 100. Multiple battery cells 100 can be connected in series, parallel, or in a hybrid configuration; a hybrid configuration means that multiple battery cells 100 are connected in both series and parallel. Multiple battery cells 100 can be directly connected in series, parallel, or in a hybrid configuration, and then the entire assembly of the multiple battery cells 100 is housed within a carrier (e.g., the battery box 300). The battery pack 1000 may also include other structures; for example, the battery pack 1000 may also include a busbar (not shown) for electrical connection between multiple battery cells 100. It is understood that the number of battery cells 100 in the battery pack 1000 can be adaptively adjusted according to the application scenario and capacity.

[0097] Please see Figure 2 , Figure 3 , Figure 6 and Figure 9 The battery cell 100 includes a top cover assembly 10, a housing 30, and a battery cell (not shown, but including at least an electrode assembly). The housing 30 has an opening, and the top cover assembly 10 is mounted on the housing 30 and closes the opening. The battery cell is housed within the housing 30. The housing 30 is a structure for mounting the battery cell. The cross-section of the housing 30 (the plane intercepted by a plane perpendicular to the thickness direction Z) may, but is not limited to, be circular, elliptical, square, or other polygonal. The material of the housing 30 includes, but is not limited to, metal or non-metal, wherein metals include aluminum, iron, steel, aluminum alloys, or iron alloys, and non-metals include, but are not limited to, plastics. In this application, the cross-section of the housing 30 is circular, which facilitates integration into a cylindrical battery cell 100. The material of the housing 30 is aluminum alloy, which, while ensuring rigidity, also makes the battery cell 100 lighter and easier to transport.

[0098] A battery cell is the core structure of a single battery cell 100 that converts electrical energy into chemical energy through a chemical reaction for charging and discharging. A battery cell is generally made by winding electrode components onto a core rod. The electrode components mainly include a negative electrode, a positive electrode, and a separator. In one possible design, the negative electrode, separator, and positive electrode are sequentially stacked and attached to the core rod by adhesive or thermal fusion, and then wound to form the battery cell. After formation, the battery cell has gaps through which electrolyte can enter. The electrolyte is used to wet the battery cell, ensuring that ions can move freely during charging and discharging. The electrolyte includes, but is not limited to, lithium salts, organic solvents, and additives. The negative electrode includes a negative current collector 14 (e.g., copper foil) and a layer of negative active material (e.g., carbon or silicon) coated on the surface of the negative current collector 14. The positive electrode includes a positive current collector 14 (e.g., aluminum foil) and a positive active material layer (e.g., ternary material, lithium iron phosphate, or lithium cobalt oxide) coated on the surface of the positive current collector 14. A separator is located between adjacent negative and positive electrodes to separate them.

[0099] The battery box 300 is a structure for holding individual battery cells 100. The cross-section of the battery box 300 (the plane intercepted by a plane perpendicular to the thickness direction Z) may, but is not limited to, be circular, elliptical, square, or other polygonal. The material of the battery box 300 includes, but is not limited to, metal or non-metal, wherein metals include aluminum, iron, steel, aluminum alloys, or iron alloys, and non-metals include, but are not limited to, plastics. In this application, the cross-section of the battery box 300 is rectangular. The material of the battery box 300 is aluminum alloy, thus, while ensuring strength, it also makes the battery pack 1000 lighter and easier to transport.

[0100] The battery box 300 includes a box body 310 and a cover 330. The box body 310 and the cover 330 are combined to form a receiving cavity, in which a battery cell 100 is received. The box body 310 is the component in the battery box 300 that loads and supports the battery cell 100. One end of the box body 310 is closed, and the other end has an opening for the battery cell 100 to be inserted into the receiving cavity. The cover 330 is the component in the battery box 300 that covers the opening. The connection between the box body 310 and the cover 330 can be detachable or non-detachable. Detachable connections include, but are not limited to, screw connections, snap-fit ​​connections, or a combination of screw connections and snap-fit ​​connections. Non-detachable connections include, but are not limited to, adhesive connections, welding, or a combination of adhesive connections and welding connections. In this application, the box body 310 and the cover 330 are detachably connected.

[0101] Furthermore, when the battery box 300 includes a body 310 and a cover 330, the battery box 300 may not be made of a single material. For example, the body 310 and the cover 330 may be made of the same material, aluminum alloy. The battery box 300 may also have different components made of different materials. For example, the body 310 may be made of metal, while the cover 330 may be made of plastic. Of course, the materials of the body 310 and the cover 330 can also be combined in other ways, which will not be listed here.

[0102] In the energy storage device of the above technical solution, the ratio P between the depth of the groove 1310 in the top cover assembly 10 and the minimum width or minimum diameter of the groove 1310 is greater than or equal to 0.14 and less than or equal to 0.49, which can ensure that there will be no connection defects between the pole post 13 and the current collector 14, and that the two can be firmly connected together, ensuring that the battery cell 100 can be charged and discharged normally.

[0103] Please see Figure 2 , Figure 3 , Figure 6 and Figure 11 This application provides an electrical appliance 10000. The electrical appliance 10000 includes an energy storage device.

[0104] Furthermore, this application also provides an electrical appliance 10000 that uses an energy storage device as its power source. The electrical appliance 10000 may include, but is not limited to, power tools, mobile phones, ships, spacecraft, or residential energy storage systems. Spacecraft may include drones, rockets, space shuttles, etc. This application only uses a residential energy storage system as an example for illustration.

[0105] The residential energy storage system includes an energy storage device (taking a battery pack 1000 as an example), a conversion device 4000 (photovoltaic panel), one type of user load 2000 (streetlight), and another type of user load 3000 (household appliance). The energy storage device can be wall-mounted on an outdoor wall. Specifically, the conversion device 4000 can be a photovoltaic conversion device installed on the roof to convert solar energy into electrical energy. The energy storage device is used to store this electrical energy and supply it to streetlights and household appliances during peak electricity prices, or to supply power during grid outages, or to supply power to the grid after grid connection. It should be noted that the energy storage device in this application is not limited to residential energy storage scenarios.

[0106] In the electrical equipment 10000 of the above technical solution, the ratio P between the depth of the groove 1310 in the top cover assembly 10 and the minimum width or minimum diameter of the groove 1310 is greater than or equal to 0.14 and less than or equal to 0.49, which can ensure that there will be no connection defects between the pole post 13 and the current collector 14, and that the two can be firmly connected together, ensuring that the battery cell 100 can be charged and discharged normally.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A top cover assembly, characterized in that, include: The top cover includes a first side and a second side opposite to each other in the thickness direction, and is provided with a first through hole that penetrates the first side and the second side of the top cover; A lower plastic insert is disposed on the second side of the top cover, and the lower plastic insert has a through-hole; and An electrode post includes an electrode post body and an electrode post ring. The electrode post body passes through a first through hole and a second through hole, and includes a first end and a second end opposite to each other. The first end protrudes from a first side opposite to the top cover and has a first end face away from the second end. The first end face has a groove recessed towards the second end. The second end extends from the second through hole in a direction away from the top cover. The electrode post ring is fixed to the outer peripheral wall of the second end, and the second end has a second end face opposite to the bottom surface of the groove. The collector plate is welded to the second end face of the pole piece. The groove satisfies the following relationship: 0.14≤P≤0.49, P=h / D, where h is the depth of the groove and D is the minimum width or minimum diameter of the groove in the plane perpendicular to the depth direction of the groove.

2. The top cover assembly according to claim 1, characterized in that, 0.20≤P≤0.40。 3. The top cover assembly according to claim 1, characterized in that, The collector plate is a non-bending type collector plate, and the bottom of the groove is connected to the collector plate by through welding; or, the bottom surface of the groove has an annular weld mark.

4. The top cover assembly according to claim 3, characterized in that, The collector plate has a connection area that is connected to the second end face, and the area of ​​the connection area is greater than or equal to the area of ​​the bottom surface of the groove.

5. The top cover assembly according to claim 1, characterized in that, The thickness T1 at the bottom of the groove and the thickness T2 of the collector plate satisfy the following relationship: 0.50≤T1 / T2≤0.

80.

6. The top cover assembly according to claim 1, characterized in that, The thickness T1 at the bottom of the groove satisfies the following relationship: 0.30mm ≤ T1 ≤ 0.60mm; and / or, The thickness T2 of the collector plate satisfies the following relationship: 0.15mm≤T2≤0.48mm.

7. The top cover assembly according to any one of claims 1-6, characterized in that, The first end of the pole piece is provided with a protrusion; the top cover assembly further includes: A plastic sleeve is fitted onto the electrode body and includes a first sub-part and a second sub-part that are in contact with each other. The first sub-part is disposed on a first side of the top cover, and at least a portion of the first sub-part is sandwiched between the top cover and the protrusion in the thickness direction of the top cover. The second sub-part passes through the first through hole and the second through hole, and forms an accommodating cavity with the inner wall of the second through hole; and A sealing element surrounds the second sub-part and is housed within the receiving cavity, and in the thickness direction of the top cover, the sealing element is sandwiched between the top cover and the pole ring.

8. The top cover assembly according to claim 7, characterized in that, The electrode ring is welded to the outer peripheral wall of the second end of the electrode body; and / or, the material of the electrode ring is the same as the material of the second end of the electrode body.

9. An energy storage device, characterized in that, The energy storage device includes the top cover assembly as described in any one of claims 1-8.

10. An electrical appliance, characterized in that, The electrical equipment includes the energy storage device as described in claim 9.

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