Secondary battery, energy storage system and electric device

Abstract

The application relates to the technical field of secondary batteries, in particular to a secondary battery, an energy storage system and a power utilization device. A cell assembly is installed in a shell, a top cover covers the shell and is electrically connected with the cell assembly. The top cover comprises a pole, a lower insulating plate, a sealing element, a supporting plate, an upper insulating element and a fixing element, the pole comprises an integrally formed connecting portion and an electrode portion, and the connecting portion is arranged at the outer periphery of the electrode portion. In the thickness direction of the top cover, the electrode portion can be fixedly connected with the lower insulating plate, the sealing element, the supporting plate, the upper insulating element and the fixing element. The connecting portion is in abutment with the sealing element and the lower insulating plate, and the connecting portion is electrically connected with the tab of the cell assembly. A reinforcing portion is arranged at the connecting position of the connecting portion and the tab, and the reinforcing portion is protruded in the direction away from the lower insulating plate. In the application, the pole is an integrally formed structure, and the electrode portion and the connecting portion no longer need to be connected, the resistance of the pole is reduced, and the energy efficiency of the cell assembly is improved. Meanwhile, the reinforcing portion can improve the structural strength of the connecting portion.

Description

Technical Field

[0001] This application relates to the field of secondary battery technology, and in particular to a secondary battery, energy storage system and electrical equipment. Background Technology

[0002] As an important component of energy storage batteries, the top cover assembly plays a role in sealing, integrating the liquid injection port, integrating the explosion-proof valve port, and transmitting and conducting current.

[0003] Currently, most battery cells connect their tabs to terminals by welding them to an adapter plate, which in turn is welded to the terminal post.

[0004] Since the welding of the terminal and the adapter plate is related to current transmission, if the welding of the terminal and the adapter plate is not good, heat may accumulate at the welding position of the terminal and the adapter plate during current transmission, resulting in high temperature inside the cell, which may cause damage to the cell or even an explosion. Utility Model Content

[0005] This application provides a secondary battery, an energy storage system, and an electrical device, aiming to ensure stable current transmission and reduce the risk of secondary battery damage.

[0006] This application provides a secondary battery in a first aspect. The secondary battery includes a top cover, a housing, and a cell assembly. The cell assembly is installed inside the housing, and the top cover covers the housing and is electrically connected to the cell assembly.

[0007] The top cover includes a pole post, a lower insulating plate, a sealing element, a support plate, an upper insulating element, and a fixing element. The pole post includes an integrally formed connecting part and an electrode part. The connecting part is disposed on the outer periphery of the electrode part. Along the thickness direction of the top cover, the electrode part can pass through the lower insulating plate, the sealing element, the support plate, the upper insulating element, and be fixedly connected to the fixing element. The connecting part abuts against the sealing element and the lower insulating plate. The connecting part is electrically connected to the tab of the battery cell assembly. A reinforcing part is provided at the connection between the connecting part and the tab. The reinforcing part protrudes in a direction away from the lower insulating plate.

[0008] In one possible design, a gap exists between the reinforcing portion and the lower insulating plate along the thickness direction of the top cover.

[0009] In one possible design, along the thickness direction of the top cover, the support plate and the upper insulating member both abut against the sealing member;

[0010] The sealing element is provided with a first abutting part, a connecting surface and a second abutting part. Along the thickness direction of the top cover, the second abutting part protrudes towards the upper insulating part compared to the first abutting part. The connecting surface connects the first abutting part and the second abutting part.

[0011] The upper insulating member is provided with an extension that protrudes toward the sealing member;

[0012] Along the thickness direction of the top cover, a portion of the support plate abuts against the first abutting portion, and the extension abuts against the second abutting portion;

[0013] Along the thickness direction perpendicular to the top cover, the inner end face of the support plate abuts against the connecting surface.

[0014] In one possible design, the electrode post includes a positive electrode post and a negative electrode post, wherein the negative electrode post is made of a copper-aluminum composite.

[0015] In one possible design, the electrode portion of the negative electrode post includes a first part and a second part, the first part being made of copper and the second part being made of aluminum. The first part and the connecting part are integrally formed, and the second part is fixedly connected to the fixing member.

[0016] The first part is provided with a riveting part, and the second part is provided with a mating part, wherein the riveting part can be riveted into the mating part.

[0017] In one possible design, there are two riveting parts, each including a first riveting part and a second riveting part connected to each other. The second riveting part is connected to the second part. Along the thickness direction perpendicular to the top cover, the cross-sectional area of ​​the first riveting part is larger than the cross-sectional area of ​​the second riveting part.

[0018] The mating part is a hole structure that penetrates the second part. There are two mating parts. The mating part includes a first mating hole and a second mating hole that are connected. Along the thickness direction perpendicular to the top cover, the diameter of the first mating hole is larger than the diameter of the second mating hole.

[0019] The first riveting part engages with the first mating hole, and the second riveting part engages with the second mating hole.

[0020] In one possible design, the mating part is a groove structure with the second part recessed inward, and the riveting part is a protruding structure with the first part protruding outward.

[0021] In the direction toward the second part, the cross-sectional area of ​​the riveted portion gradually increases along the thickness direction of the top cover;

[0022] In the direction toward the first part, the cross-sectional area of ​​the mating part gradually decreases along the thickness direction of the top cover.

[0023] In one possible design, there are weld marks between the first part and the second part.

[0024] In one possible design, the electrode post includes a positive electrode post and a negative electrode post, wherein the negative electrode post is made of copper.

[0025] Along the thickness direction perpendicular to the top cover, the negative electrode post is provided with a protrusion that protrudes outward, and the fixing member is provided with a recessed connecting groove, and the protrusion and the connecting groove are interference fit.

[0026] There are welding marks between the negative electrode post and the fixing component.

[0027] In one possible design, the support plate is provided with a first limiting part, and the upper insulating member is installed on the first limiting part;

[0028] The upper insulating member is provided with a second limiting part, and the fixing member is installed on the second limiting part.

[0029] In a second aspect, this application also provides an energy storage system, which includes a plurality of the aforementioned secondary batteries.

[0030] In a third aspect, this application also provides an electrical device, which includes the energy storage system described above.

[0031] In this embodiment, the electrode post is a one-piece molded structure, eliminating the need for welding or riveting between the electrode part and the connecting part. This reduces the resistance of the electrode post and helps improve the energy efficiency of the battery cell assembly. Simultaneously, reducing one connection step on the electrode post lowers processing costs and optimizes the assembly process of the top cover.

[0032] In addition, the one-piece molded structure of the terminal post avoids the phenomenon of local heat accumulation, ensuring stable current transmission of the secondary battery and reducing the risk of damage to the secondary battery.

[0033] In addition, a reinforcing part is provided at the connection between the connecting part and the electrode tab. The reinforcing part protrudes in a direction away from the lower insulating plate. This reinforcing part can improve the structural strength of the connecting part, thereby increasing the mechanical strength of the contact surface between the connecting part and the seal, and enhancing the connection strength between the connecting part and the electrode tab.

[0034] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0035] Figure 1An exploded view of the secondary battery provided in this application;

[0036] Figure 2 This is a schematic diagram showing the connection between the battery pack and the battery cell assembly provided in this application;

[0037] Figure 3 This is a structural schematic diagram of the top cover provided in this application;

[0038] Figure 4 for Figure 3 An explosion diagram;

[0039] Figure 5 This is a schematic diagram of the pole provided in this application;

[0040] Figure 6 for Figure 3 A cross-sectional view;

[0041] Figure 7 for Figure 6 Enlarged schematic diagram of the positive electrode section;

[0042] Figure 8 for Figure 6 Enlarged schematic diagram of the negative electrode section;

[0043] Figure 9 This is a structural schematic diagram of the seal provided in this application;

[0044] Figure 10 This is a schematic diagram of the structure of the upper insulating component provided in this application;

[0045] Figure 11 This is a structural schematic diagram of the support plate provided in this application;

[0046] Figure 12 This is a schematic diagram of the structure of the upper insulating component provided in this application;

[0047] Figure 13 This is a cross-sectional schematic diagram of the negative electrode post provided in this application in one embodiment;

[0048] Figure 14 This is a cross-sectional schematic diagram of the negative electrode post provided in this application in another embodiment;

[0049] Figure 15 This is a cross-sectional schematic diagram of the negative electrode post provided in this application in another embodiment;

[0050] Figure 16 This is a cross-sectional schematic diagram of the negative electrode post provided in this application in another embodiment;

[0051] Figure 17 for Figure 16 A cross-sectional view of the connection between the negative terminal and the fixing component.

[0052] Figure label:

[0053] 1-Top cover;

[0054] 11-Pole Post;

[0055] 111-Connecting part;

[0056] 111a - Reinforced section;

[0057] 111b - Gap;

[0058] 112 - Electrode section;

[0059] 112a - Part 1;

[0060] 112a1 - Riveting part;

[0061] 112a11 - First riveting part;

[0062] 112a12 - Second riveting part;

[0063] 112b - Part Two;

[0064] 112b1 - Fitting part;

[0065] 112b11 - First mating hole;

[0066] 112b12 - Second mating hole;

[0067] 112c - Protrusion;

[0068] 11a - Positive terminal;

[0069] 11b - Negative terminal;

[0070] 12-Lower insulation board;

[0071] 13-Seals;

[0072] 131 - First contact point;

[0073] 132 - Second contact section;

[0074] 133 - Connection surface;

[0075] 14-Support plate;

[0076] 141 - First limiting part;

[0077] 15 - Upper insulation component;

[0078] 151-Extension;

[0079] 152 - Second limiting part;

[0080] 16-Factor;

[0081] 161 - Connecting slot;

[0082] 2-Shell;

[0083] 3-Battery cell assembly;

[0084] 31-Ear;

[0085] 4-Beta.

[0086] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0087] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0088] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0089] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0090] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0091] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0092] Typically, the top cover's pole consists of two parts: a connecting tab and an electrode. The connecting tab is electrically connected to the tab of the battery cell assembly, and the electrode is electrically connected to the electrode plate. The connecting tab and the electrode are connected by welding or riveting.

[0093] However, the terminals connected by welding or riveting are thicker and have higher resistance, which affects the energy efficiency of the battery cell assembly. Under high current, the overall heat power of the terminals is higher and the temperature rises quickly, which affects the performance of the secondary battery.

[0094] To address these technical problems, this application provides a secondary battery. The structure of the secondary battery will be described in detail below with reference to the accompanying drawings.

[0095] Figure 1 This is an exploded schematic diagram of a secondary battery. The secondary battery includes a top cover 1, a housing 2, and a cell assembly 3. The housing 2 has a receiving cavity (not shown in the figure), and the cell assembly 3 is installed inside the receiving cavity of the housing 2. The top cover 1 is installed on the housing 2 and seals the receiving cavity, thus sealing the cell assembly 3. The cell assembly 3 has tabs 31 (metal conductors) extending from its interior. The terminals of the top cover 1 (not shown in the figure) are electrically connected to the tabs 31, enabling the charging and discharging current of the cell assembly 3 to flow.

[0096] Figure 2 The diagram shows the connection of the battery cell assembly 3, the top cover 1, and the battery pack 4. The side of the top cover 1 away from the battery cell assembly 3 is electrically connected to the battery pack 4, so that the battery pack 4 can effectively collect the current generated by the secondary battery and transmit it to the external circuit.

[0097] Among them, the battery plate 4 can be made of aluminum. Aluminum has low resistance and good conductivity, which can reduce energy loss and improve the energy conversion efficiency of the secondary battery. Aluminum also has high chemical stability and mechanical strength, ensuring that the battery plate 4 can maintain good performance during operation and has sufficient durability to withstand long-term working environment and cyclic use.

[0098] The possible structure of the top cover will be described in detail below with reference to the accompanying drawings.

[0099] Please refer to the reference for details. Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the top cover 1. Figure 4This is an exploded view of the top cover 1. The top cover 1 includes a pole 11, a lower insulating plate 12, a sealing element 13, a support plate 14, an upper insulating element 15, and a fixing element 16. The pole 11 includes a positive pole 11a and a negative pole 11b. Two sealing elements 13, two upper insulating elements 15, and two fixing elements 16 are provided. The sealing element 13, the upper insulating element 15, and the fixing element 16 are all annular structures. The upper insulating element 15 and the lower insulating plate 12 each have two holes. A portion of the positive pole 11a can pass through the lower insulating plate 12, the sealing element 13, the support plate 14, and the upper insulating element 15 to be fixedly connected to the fixing element 16. A portion of the negative pole 11b can pass through the lower insulating plate 12, the sealing element 13, the support plate 14, and the upper insulating element 15 to be fixedly connected to the fixing element 16.

[0100] Please refer to Figure 5 , Figure 5 The diagram shows the structure of the electrode post 11 (positive electrode post 11a and negative electrode post 11b). The electrode post 11 (positive electrode post 11a and negative electrode post 11b) includes an integrally formed connecting part 111 and an electrode part 112. The electrode plate has a raised structure, and the connecting part 111 has a plate-like structure. The connecting part 111 is disposed on the outer periphery of the electrode part 112. Along the thickness direction Y perpendicular to the top cover 1, the cross-section of the electrode post 11 is approximately "U" shaped.

[0101] The electrode posts 11 (positive electrode post 11a and negative electrode post 11b) can be formed by stamping sheet metal to make the connecting part 111 and the electrode part 112 an integral structure. Specifically, the electrode post 11 can be formed by first stretching the sheet metal to form the electrode part 112, and then cold-forging the stretched portion to form a sharp corner at the top of the formed electrode part 112 for welding, facilitating welding of the electrode part 112 to the fixing member 16. Then, the remaining portion of the sheet metal is stamped to form the connecting part 111.

[0102] It is understandable that the forming process of the pole post 11 may also include other steps, such as trimming, which will not be described in detail in this embodiment.

[0103] Specifically, please refer to the reference. Figures 6 to 8 , Figure 6 This is a cross-sectional view of the top cover 1. Figure 7 for Figure 6 Cross-sectional view of the positive electrode post 11a. Figure 8 for Figure 6A cross-sectional view of the negative electrode post 11b shows that, along the thickness direction Z of the top cover 1, one side of the connection portion 111 (of the positive electrode post 11a and the negative electrode post 11b) abuts against the sealing member 13 and the lower insulating plate 12. The electrode portion 112 (of the positive electrode post 11a and the negative electrode post 11b) can pass through the lower insulating plate 12, the sealing member 13, the support plate 14, the upper insulating member 15, and is fixedly connected to the fixing member 16. Furthermore, the side of the connection portion 111 (of the positive electrode post 11a and the negative electrode post 11b) away from the lower insulating plate 12 can be electrically connected to the tab 31 of the cell assembly 3.

[0104] In this embodiment, the electrode post 11 is a one-piece molded structure, which eliminates the need for welding or riveting between the electrode part 112 and the connecting part 111, reducing the resistance of the electrode post 11 and improving the energy efficiency of the battery cell assembly 3. At the same time, reducing one connection process on the electrode post 11 lowers the processing cost and optimizes the assembly process of the top cover 1.

[0105] In addition, the electrode post 11 is a one-piece molded structure, which also avoids the phenomenon of local heat accumulation in the electrode post 11, ensuring stable current transmission of the secondary battery and reducing the risk of secondary battery damage.

[0106] Please continue to refer to the reference. Figure 7 and Figure 8 A reinforcing part 111a is provided at the connection between the connecting part 111 and the tab 31. The reinforcing part 111a protrudes in a direction away from the lower insulating plate 12. The reinforcing part 111a can improve the structural strength of the connecting part 111, thereby increasing the mechanical strength of the contact surface between the connecting part 111 and the sealing member 13, and enhancing the connection strength between the connecting part 111 and the tab 31.

[0107] Furthermore, along the thickness direction Z of the top cover 1, since the reinforcing part 111a protrudes in a direction away from the lower insulating plate 12, there is a gap 111b between the reinforcing part 111a and the lower insulating plate 12. When the connecting piece and the cell assembly 3 are laser welded, the gap 111b can isolate the lower insulating plate 12 and prevent the lower insulating plate 12 from melting due to the welding heat.

[0108] Please continue to refer to the reference. Figure 7 and Figure 8 Along the thickness direction Z of the top cover 1, the support plate 14 and the upper insulating member 15 both abut against the sealing member 13. That is to say, in this embodiment, a sealing member 13 is provided between the upper insulating member 15 and the connecting part 111, as well as between the support plate 14 and the connecting part 111. This increases the number of parts in the top cover 1 that can contact the sealing member 13, makes full use of the buffering effect of the sealing member 13, reduces the risk of parts being crushed during the assembly of the top cover 1, and improves the production qualification rate of the top cover 1.

[0109] For details, please refer to Figure 9 , Figure 9 The diagram shows the structure of the seal 13. The seal 13 has a first abutment portion 131, a connecting surface 133, and a second abutment portion 132. Along the thickness direction Z of the top cover 1, the second abutment portion 132 protrudes upward toward the insulating member 15 compared to the first abutment portion 131. The connecting surface 133 connects the first abutment portion 131 and the second abutment portion 132. That is, along the thickness direction Y perpendicular to the top cover 1, the cross-section of the seal 13 can be L-shaped.

[0110] It should be noted that the seal 13 is an overall annular structure, and the "L" shape of the cross-section of the seal 13 refers to the fact that the cross-section of one side of the seal 13 is "L" shaped.

[0111] Please refer to Figure 10 , Figure 10 This is a schematic diagram of the structure of the upper insulating member 15, which has an extension 151 protruding toward the sealing member 13.

[0112] Please continue to refer to the reference. Figures 7 to 10 Along the thickness direction Z of the top cover 1, part of the structure of the support plate 14 abuts against the first abutting part 131, and the extension part 151 abuts against the second abutting part 132, thereby realizing that the support plate 14 and the upper insulating member abut against the sealing member 13.

[0113] In this embodiment, the upper insulating member 15 can be made of ceramic material, which has excellent properties such as high temperature resistance, pressure resistance, corrosion resistance, and high mechanical strength, thereby giving the pole post 11 good performance.

[0114] Furthermore, along the thickness direction Y perpendicular to the top cover 1, the inner end face of the support plate 14 abuts against the outer wall of the connecting surface 133 and the extension 151, thereby achieving a tight fit between the support plate 14 and the sealing element 13 and the upper insulating element 15, and the connecting surface 133 and the outer wall of the extension 151 can limit the installation of the support plate 14.

[0115] Please refer to Figure 11 , Figure 11 The diagram shows the structure of the support plate 14. The support plate 14 is provided with a first limiting part 141, which can be a groove structure. The first limiting part 141 is located on the outer periphery of the hole structure on the support plate 14.

[0116] Please refer to Figure 12 , Figure 12 The diagram shows the structure of the upper insulating member 15. The upper insulating member 15 is provided with a second limiting part 152, which can be a groove structure. The second limiting part 152 is located on the outer periphery of the upper hole structure of the upper insulating member 15.

[0117] Please refer to the reference. Figure 7 , Figure 8, Figure 11 and Figure 12 The upper insulating member 15 is installed on the first limiting part 141, and the outer side of the upper insulating member 15 abuts against the inner side of the first limiting part 141, so that the first limiting part 141 can limit the installation of the upper insulating member 15. The fixing member 16 is installed on the second limiting part 152, and the outer side of the fixing member 16 abuts against the inner side of the second limiting part 152, so that the second limiting part 152 can limit the installation of the fixing member 16.

[0118] In some embodiments, the positive electrode post 11a can be made of aluminum plate, and the negative electrode post 11b can be made of copper-aluminum composite plate.

[0119] Please refer to the details. Figure 13 , Figure 13 This is a cross-sectional schematic diagram of the negative electrode post 11b in one embodiment. The electrode portion 112 of the negative electrode post 11b includes a first portion 112a and a second portion 112b. The first portion 112a is made of copper, and the second portion 112b is made of aluminum. The first portion 112a and the connecting portion 111 are integrally formed, and the second portion 112b is fixedly connected to the fixing member 16.

[0120] In this embodiment, the negative electrode post 11b can be formed by stamping a copper-aluminum composite plate, so that the first part 112a and the second part 112b are integrally formed. Specifically, the forming method of the negative electrode post 11b can be as follows: first, the plate is stretched to form the electrode portion 112, i.e., the first part 112a and the second part 112b. The stretched portion is then cold-forged to form a sharp corner on the top of the formed electrode portion 112 (the second part 112b) for welding, facilitating welding of the electrode portion 112 (the second part 112b) to the fixing member 16. Then, the remaining portion of the plate is stamped to form the connecting portion 111. Finally, the negative electrode post 11b is machined so that the second part 112b is made of aluminum, and the first part 112a and the connecting portion 111 are made of copper.

[0121] Alternatively, in other embodiments, during the forming process of the negative electrode post 11b, the aluminum material portion that will exist in the cell assembly 3 can be removed first after the copper-aluminum composite is formed, and then the negative electrode post 11b can be formed.

[0122] In this embodiment, by setting the second part 112b of the negative electrode post 11b to be made of aluminum, the second part 112b and the bar plate 4 are made of the same material, which facilitates the welding connection between the negative electrode post 11b and the bar plate 4 and improves the connection reliability between the negative electrode post 11b and the bar plate 4.

[0123] Alternatively, in some embodiments, the first part 112a and the second part 112b can be separate structures.

[0124] Please refer to the details. Figure 14 , Figure 14 This is a cross-sectional schematic diagram of the negative electrode post 11b in another embodiment. The electrode portion 112 of the negative electrode post 11b includes a first portion 112a and a second portion 112b. The first portion 112a is made of copper, and the second portion 112b is made of aluminum. The first portion 112a is provided with a riveting portion 112a1, and the second portion 112b is provided with a mating portion 112b1. The riveting portion 112a1 can be riveted into the mating portion 112b1.

[0125] In this embodiment, the first part 112a and the second part 112b are connected by riveting, which gives them high connection strength and improves the reliability of their connection.

[0126] For more details, please refer to [link / reference]. Figure 14 Two riveting portions 112a1 are provided, each including a first riveting portion 112a11 and a second riveting portion 112a12 connected to each other. The second riveting portion 112a12 is connected to the second part 112b. Along the thickness direction Y perpendicular to the top cover 1, the cross-sectional area of ​​the first riveting portion 112a11 is larger than that of the second riveting portion 112a12. That is, along the thickness direction Y perpendicular to the top cover 1, the cross-section of the riveting portion 112a1 has a T-shaped structure. The mating portion 112b1 is a hole structure penetrating the second part 112b. Two mating portions 112b1 are provided, each including a first mating hole 112b11 and a second mating hole 112b12 connected to each other. Along the thickness direction Y perpendicular to the top cover 1, the diameter of the first mating hole 112b11 is larger than that of the second mating hole 112b12. In other words, along the thickness direction Y perpendicular to the top cover 1, the cross-section of the mating part 112b1 has an inverted T-shaped structure. After the riveting part 112a1 is riveted into the mating part 112b1, the first riveting part 112a11 mates with the first mating hole 112b11, and the second riveting part 112a12 mates with the second mating hole 112b12.

[0127] In this embodiment, by setting the cross-section of the riveting part 112a1 to a T-shaped structure and the cross-section of the mating part 112b1 to an inverted T-shaped structure, the riveting part 112a1 and the mating part 112b1 are riveted together, thus preventing the riveting part 112a1 from separating from the mating part 112b1, thereby improving the connection strength between the riveting part 112a1 and the mating part 112b1, and thus enhancing the connection strength between the first part 112a and the second part 112b.

[0128] Please continue to refer to this. Figure 14There are weld marks (not shown in the figure) between the first part 112a and the second part 112b. The weld marks refer to the traces or marks left on the material after the first part 112a and the second part 112b are welded together. The shape of the weld marks formed after the first part 112a and the second part 112b are welded can be cylindrical, polygonal, etc.

[0129] In other words, in this embodiment, after the first part 112a and the second part 112b are riveted together, the first part 112a and the second part 112b are also laser welded to enhance the connection strength between the first part 112a and the second part 112b.

[0130] Alternatively, please refer to Figure 15 , Figure 15 This is a schematic diagram of the negative electrode post 11b in another embodiment. The electrode portion 112 of the negative electrode post 11b includes a first portion 112a and a second portion 112b. The first portion 112a is made of copper, and the second portion 112b is made of aluminum. The first portion 112a is provided with a riveting portion 112a1, and the second portion 112b is provided with a mating portion 112b1. The riveting portion 112a1 can be riveted into the mating portion 112b1.

[0131] In this embodiment, the first part 112a and the second part 112b are connected by riveting, which gives them high connection strength and improves the reliability of their connection.

[0132] More specifically, the mating part 112b1 is a groove structure that is recessed inward on the side of the second part 112b near the first part 112a, and the riveting part 112a1 is a protruding structure that is protruding outward on the side of the first part 112a near the second part 112b. In the direction towards the second part 112b, the cross-sectional area of ​​the riveting part 112a1 gradually increases along the thickness direction Z of the top cover 1. That is, in the direction perpendicular to the thickness direction Y of the top cover 1, the cross-section of the riveting part 112a1 has an inverted trapezoidal structure. In the direction towards the first part 112a, the cross-sectional area of ​​the mating part 112b1 gradually decreases along the thickness direction Z of the top cover 1. That is, in the direction perpendicular to the thickness direction Y of the top cover 1, the cross-section of the mating part 112b1 has a trapezoidal structure.

[0133] In this embodiment, by setting the cross-section of the riveting part 112a1 to an inverted trapezoidal structure and the cross-section of the mating part 112b1 to a trapezoidal structure, the riveting part 112a1 and the mating part 112b1 are riveted together, thus preventing the riveting part 112a1 from separating from the mating part 112b1, thereby improving the connection strength between the riveting part 112a1 and the mating part 112b1, and thus enhancing the connection strength between the first part 112a and the second part 112b.

[0134] Please continue to refer to this. Figure 15There are weld marks (not shown in the figure) between the first part 112a and the second part 112b. The weld marks refer to the traces or marks left on the material after the first part 112a and the second part 112b are welded together. The shape of the weld marks formed after the first part 112a and the second part 112b are welded can be cylindrical, polygonal, etc.

[0135] In other words, in this embodiment, after the first part 112a and the second part 112b are riveted together, the first part 112a and the second part 112b are also laser welded to enhance the connection strength between the first part 112a and the second part 112b.

[0136] In some embodiments, the positive electrode post 11a can be made of aluminum plate and the negative electrode post 11b can be made of copper plate.

[0137] Please refer to the details. Figure 16 , Figure 16 This is a cross-sectional view of the negative electrode post 11b in another embodiment. Along the thickness direction Y perpendicular to the top cover 1, the negative electrode post 11b is provided with a protrusion 112c that protrudes outward.

[0138] Please refer to Figure 17 , Figure 17 This is a cross-sectional view showing the connection between the negative terminal 11b and the fixing member 16. The fixing member 16 has a recessed connecting groove 161, and the protrusion 112c is interference-fitted with the connecting groove 161. That is, along the thickness direction Y perpendicular to the top cover 1, the width of the protrusion 112c is greater than the width of the connecting groove 161, so that the protrusion 112c and the mating part 112b1 can be riveted together, thereby realizing the fixed connection between the negative terminal 11b and the fixing member 16.

[0139] In this embodiment, there are weld marks (not shown in the figure) between the negative electrode post 11b and the fixing member 16. Here, weld marks refer to the traces or imprints left on the material after the negative electrode post 11b and the fixing member 16 are welded. The shape of the weld marks formed after the negative electrode post 11b and the fixing member 16 are welded can be cylindrical, polygonal, etc.

[0140] In this embodiment, after the negative electrode post 11b is riveted to the fixing member 16, the negative electrode post 11b and the fixing member 16 are laser welded to enhance the connection strength between the negative electrode post 11b and the fixing member 16.

[0141] This application also provides an energy storage system, which includes multiple secondary batteries as described above.

[0142] This application also provides an electrical device, which includes the energy storage system described above.

[0143] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A secondary battery, characterized in that, The secondary battery includes a top cover, a housing, and a cell assembly. The cell assembly is installed inside the housing, and the top cover covers the housing and is electrically connected to the cell assembly. The top cover includes a pole post, a lower insulating plate, a sealing element, a support plate, an upper insulating element, and a fixing element. The pole post includes an integrally formed connecting part and an electrode part. The connecting part is disposed on the outer periphery of the electrode part. Along the thickness direction of the top cover, the electrode part can pass through the lower insulating plate, the sealing element, the support plate, the upper insulating element, and be fixedly connected to the fixing element. The connecting part abuts against the sealing element and the lower insulating plate. The connecting part is electrically connected to the tab of the battery cell assembly. A reinforcing part is provided at the connection between the connecting part and the tab. The reinforcing part protrudes in a direction away from the lower insulating plate.

2. The secondary battery according to claim 1, characterized in that, Along the thickness direction of the top cover, there is a gap between the reinforcing part and the lower insulating plate.

3. The secondary battery according to claim 1, characterized in that, Along the thickness direction of the top cover, the support plate and the upper insulating member both abut against the sealing member; The sealing element is provided with a first abutting part, a connecting surface and a second abutting part. Along the thickness direction of the top cover, the second abutting part protrudes towards the upper insulating part compared to the first abutting part. The connecting surface connects the first abutting part and the second abutting part. The upper insulating member is provided with an extension that protrudes toward the sealing member; Along the thickness direction of the top cover, a portion of the support plate abuts against the first abutting portion, and the extension abuts against the second abutting portion; Along the thickness direction perpendicular to the top cover, the inner end face of the support plate abuts against the connecting surface.

4. The secondary battery according to any one of claims 1 to 3, characterized in that, The electrode includes a positive electrode and a negative electrode, and the negative electrode is made of a copper-aluminum composite.

5. The secondary battery according to claim 4, characterized in that, The electrode portion of the negative electrode post includes a first part and a second part. The first part is made of copper, and the second part is made of aluminum. The first part and the connecting part are integrally formed, and the second part is fixedly connected to the fixing member. The first part is provided with a riveting part, and the second part is provided with a mating part, wherein the riveting part can be riveted into the mating part.

6. The secondary battery according to claim 5, characterized in that, The riveting part is provided in two parts, and the riveting part includes a first riveting part and a second riveting part connected to each other. The second riveting part is connected to the second part. Along the thickness direction perpendicular to the top cover, the cross-sectional area of ​​the first riveting part is larger than the cross-sectional area of ​​the second riveting part. The mating part is a hole structure that penetrates the second part. There are two mating parts. The mating part includes a first mating hole and a second mating hole that are connected. Along the thickness direction perpendicular to the top cover, the diameter of the first mating hole is larger than the diameter of the second mating hole. The first riveting part engages with the first mating hole, and the second riveting part engages with the second mating hole.

7. The secondary battery according to claim 5, characterized in that, The mating part is a groove structure that is recessed inward in the second part, and the riveting part is a protruding structure that is protruding outward in the first part; In the direction toward the second part, the cross-sectional area of ​​the riveted portion gradually increases along the thickness direction of the top cover; In the direction toward the first part, the cross-sectional area of ​​the mating part gradually decreases along the thickness direction of the top cover.

8. The secondary battery according to claim 5, characterized in that, There are welding marks between the first part and the second part.

9. The secondary battery according to any one of claims 1 to 3, characterized in that, The electrode includes a positive electrode and a negative electrode, and the negative electrode is made of copper. Along the thickness direction perpendicular to the top cover, the negative electrode post is provided with a protrusion that protrudes outward, and the fixing member is provided with a recessed connecting groove, and the protrusion and the connecting groove are interference fit. There are welding marks between the negative electrode post and the fixing component.

10. The secondary battery according to any one of claims 1 to 3, characterized in that, The support plate is provided with a first limiting part, and the upper insulating member is installed on the first limiting part; The upper insulating member is provided with a second limiting part, and the fixing member is installed on the second limiting part.

11. An energy storage system, characterized in that, The energy storage system includes a plurality of secondary batteries as described in any one of claims 1 to 10.

12. An electrical appliance, characterized in that, The electrical equipment includes the energy storage system as described in claim 11.

Images