Battery monomer and preparation method thereof, battery device, energy storage device and power utilization device

Abstract

The invention relates to the technical field of energy storage, and discloses a battery monomer and a preparation method thereof, a battery device, an energy storage device and a power utilization device, which can be beneficial to improving the working performance of the battery monomer. The battery monomer comprises a shell, a battery cell assembly and a top cover assembly, the shell is provided with an opening. The battery core assembly is arranged in the shell; the top cover assembly comprises a cover body connected with the shell and used for sealing the opening, a positive pole column and a negative pole column which are connected with the cover body, a first connecting piece connected with the positive pole column, and a second connecting piece connected with the negative pole column. The positive pole comprises a first main body part, a first connecting part protruding and extending from the edge of the first main body part, and a first extending part extending from the edge of the first main body part to the interior of the shell, the first extending part comprises a first transition part and a first butt joint part which are connected, and the first butt joint part is connected with the first connecting piece; and the connecting part of the first butt joint part and the first connecting sheet is flush with one side close to the battery cell assembly.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a battery cell and its preparation method, a battery device, an energy storage device, and an electrical device. Background Technology

[0002] With the continuous development of new energy technologies, the demand for energy storage systems is also increasing. Energy storage systems can effectively store electrical energy and output it when needed. Energy storage systems use individual battery cells as energy storage units. These battery cells have good charge-discharge cycle characteristics, enabling the formation of electrochemical energy storage systems with a wide range of applications.

[0003] As a crucial component of energy storage systems, individual battery cells significantly impact the overall performance of the system. In particular, as the energy storage units, the performance of individual battery cells determines the amount of electrical energy the system can store and its charge / discharge efficiency. Therefore, designing the structure of individual battery cells to improve their performance is a critical issue. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell and its preparation method, battery device, energy storage device, and power consumption device, which can help improve the working performance of the battery cell.

[0005] To address the aforementioned technical problems, embodiments of this application provide a battery cell. The battery cell includes a housing, a cell assembly, and a top cover assembly. The housing has an opening. The cell assembly is disposed within the housing. The top cover assembly includes a cover connected to the housing and closing the opening, a positive terminal and a negative terminal connected to the cover, a first connecting piece connected to the positive terminal, and a second connecting piece connected to the negative terminal. The positive electrode post includes a first main body, a first connecting portion protruding from the edge of the first main body, and a first extension portion extending from the edge of the first main body toward the inside of the housing. The first extension portion includes a first transition portion and a first mating portion connected together. The first mating portion is connected to a first connecting piece, and the connection between the first mating portion and the first connecting piece is flush with the side near the cell assembly. The negative electrode post includes a second main body, a second connecting portion protruding from the edge of the second main body, and a second extension portion extending from the edge of the second main body toward the inside of the housing. The second extension portion includes a second transition portion and a second mating portion connected together. The second mating portion is connected to a second connecting piece, and the connection between the second mating portion and the second connecting piece is flush with the side near the cell assembly.

[0006] The embodiments of this application also provide a method for preparing a battery cell, the method comprising: Provide a housing with an opening; Place the battery cell assembly into the housing; A positive electrode post and a negative electrode post are provided. The positive electrode post includes a first main body, a first connecting part protruding from the edge of the first main body, and a first extension part extending from the edge of the first main body along a third direction. The first extension part includes a first transition part and a first mating part connected together. The negative electrode post includes a second main body, a second connecting part protruding from the edge of the second main body, and a second extension part extending from the edge of the second main body along a fourth direction. The second extension part includes a second transition part and a second mating part connected together. The first mating part of the positive electrode post is passed through the cover, and the first connecting piece is butt-welded to the first mating part, and the mating point of the first connecting piece and the first mating part is flush with the side away from the cover. The second mating part of the negative electrode post is passed through the cover, and the second connecting piece and the second mating part are butt-welded, and the mating point of the second connecting piece and the second mating part is flush with the side away from the cover. The cover is welded to the shell and the opening is sealed.

[0007] The embodiments of this application also provide a battery device, which includes the battery cell described above, or a battery cell manufactured by the method described above for preparing the battery cell.

[0008] The embodiments of this application also provide an energy storage device, which includes the battery device described above, and the battery device is used to store electrical energy.

[0009] The embodiments of this application also provide an electrical device, which includes the battery device described above, and the battery device is used to provide electrical energy.

[0010] The battery cell and its preparation method, battery device, energy storage device, and power consumption device provided in the embodiments of this application, when the terminal post and the connecting piece are connected, make the connection point of the terminal post and the connecting piece flush with the side close to the cell assembly, thereby making the connecting piece and the terminal post fit in a close position, reducing the occupation of the internal space of the casing, thereby increasing the storage space of the cell assembly, which is beneficial to improving the battery capacity and improving the working performance of the battery cell.

[0011] In some embodiments, the first extension is arranged in a ring shape, the first connecting piece is arranged around the first mating portion, and / or, the second extension is arranged in a ring shape, the second connecting piece is arranged around the second mating portion.

[0012] In some embodiments, a first cavity is formed on the inner side of the first extension away from the first connecting piece, and a second cavity is formed on the inner side of the second extension away from the second connecting piece.

[0013] In some embodiments, in the first direction, the size of the first transition portion is larger than the size of the first mating portion, and the size of the second transition portion is larger than the size of the second mating portion.

[0014] In some embodiments, the second main body and the second transition portion include a first metal layer and a second metal layer, the first metal layer and the second metal layer are made of different materials, and the second mating portion and the second connecting portion are made of different materials.

[0015] In some embodiments, a first chamfer is provided on the inner side of the first mating portion away from the first connecting piece, and a second chamfer is provided on the inner side of the second mating portion away from the second connecting piece.

[0016] In some embodiments, the first main body and / or the second main body are provided with an explosion-proof valve or a liquid injection port.

[0017] In some embodiments, the minimum size of the first main body portion and / or the second main body portion in the second direction is 0.3 mm to 1 mm.

[0018] In some embodiments, the first connecting piece is provided with a first protrusion that extends toward the second connecting piece, and the second connecting piece is provided with a second protrusion that extends toward the first connecting piece.

[0019] In some embodiments, in the second direction, the dimensions of the first mating portion and / or the second mating portion are 0.3 mm to 3 mm.

[0020] In some embodiments, the dimensions of the first main body portion and / or the second main body portion are 1 mm to 5 mm in the second direction.

[0021] In some implementations, the surface area of ​​the positive and / or negative terminal on the side furthest from the cell assembly is 50 mm². 2 ~1000mm 2 .

[0022] In some embodiments, the projection outline of the positive electrode post and / or negative electrode post on the cover along the second direction is circular, square, rectangular or elliptical. Attached Figure Description

[0023] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0024] Figure 1 This is a three-dimensional structural diagram of a battery cell provided in an embodiment of this application; Figure 2 This is a schematic diagram of the exploded structure of a single battery cell provided in an embodiment of this application; Figure 3This is a schematic diagram of the structure of a battery cell with an insulating film provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the cell assembly in the battery cell provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of a single bare cell in a battery cell provided in the embodiments of this application; Figure 6 This is an exploded structural diagram of the top cover assembly in a battery cell provided in an embodiment of this application; Figure 7 This is a schematic diagram of the cooperation structure between the top cover assembly, the cell assembly, and the battery cell in the battery cell provided in the embodiments of this application; Figure 8 This is a schematic diagram of the mating structure between the top cover assembly and the battery cell provided in the embodiments of this application; Figure 9 This is a top view of the battery cell top cover assembly and the battery plate provided in the embodiments of this application. Figure 10 It is along Figure 9 Schematic diagram of the cross-sectional structure along the AA direction; Figure 11 yes Figure 10 Enlarged structural diagram at point B; Figure 12 yes Figure 10 Enlarged structural diagram at point C; Figure 13 This is a schematic diagram of the front view structure of the positive electrode post in a battery cell provided in the embodiments of this application; Figure 14 This is a cross-sectional view of the positive electrode post in a battery cell provided in an embodiment of this application; Figure 15 This is a schematic diagram of the front view of the negative electrode post in a battery cell provided in the embodiments of this application; Figure 16 This is a cross-sectional view of the negative electrode post in a battery cell provided in an embodiment of this application; Figure 17 This is a partially enlarged structural diagram of a battery cell with an explosion-proof valve installed in the positive electrode post provided in the embodiments of this application; Figure 18 This is a partially enlarged structural diagram of a battery cell with an injection hole provided in an embodiment of this application. Figure 19 This is a flowchart of the method for preparing a single battery cell provided in the embodiments of this application; Figure 20 This is a schematic diagram of the structure of the first basic component formed when the positive electrode post is manufactured according to an embodiment of this application; Figure 21 This is a schematic diagram of the structure of the first intermediate component formed during the fabrication of the positive electrode post in an embodiment of this application; Figure 22 This is a schematic cross-sectional view of the first intermediate component formed during the fabrication of the positive electrode post in an embodiment of this application. Figure 23 This is a schematic diagram of the structure of the first intermediate component after edge shearing during the fabrication of the positive electrode post in an embodiment of this application; Figure 24 This is a schematic cross-sectional view of the first intermediate component after edge shearing during the fabrication of the positive electrode post in an embodiment of this application. Figure 25 This is a schematic diagram of the structure of the positive electrode post formed according to the embodiments of this application; Figure 26 This is a schematic diagram of the cross-sectional structure of the positive electrode post formed according to an embodiment of this application; Figure 27 This is a schematic diagram of the structure of the second basic component formed when the negative electrode post is manufactured according to an embodiment of this application; Figure 28 This is a schematic diagram of the structure of the second intermediate component formed during the fabrication of the negative electrode post in an embodiment of this application; Figure 29 This is a schematic diagram of the cross-sectional structure of the second intermediate component formed during the fabrication of the negative electrode post in an embodiment of this application; Figure 30 This is a schematic diagram of the structure of the second intermediate component after edge shearing during the fabrication of the negative electrode post in this application embodiment; Figure 31 This is a schematic diagram of the cross-sectional structure of the second intermediate component after edge shearing during the fabrication of the negative electrode post in an embodiment of this application; Figure 32 This is a schematic diagram of the structure of the negative electrode post formed according to the embodiments of this application; Figure 33 This is a schematic diagram of the cross-sectional structure of the negative electrode post formed according to an embodiment of this application; Figure 34 This is a schematic diagram of the battery pack structure provided in the embodiments of this application; Figure 35 This is an exploded structural diagram of the battery pack provided in an embodiment of this application; Figure 36 This is a schematic diagram of the energy storage cabinet provided in the embodiments of this application; Figure 37 This is a structural schematic diagram of the energy storage container provided in the embodiments of this application.

[0025] Reference numerals: 10, battery cell; 11, casing; 111, opening; 12, cell assembly; 121, positive electrode tab; 122, negative electrode tab; 13, top cover assembly; 131, cover; 1311, first terminal hole; 1312, second terminal hole; 1313, explosion-proof valve structure; 1314, explosion-proof valve patch; 132, positive terminal; 1321, first main body; 1322, first connecting part; 1323 1324. First extension; 1325. First transition section; 1326. First docking section; 1327. First cavity; 1328. Explosion-proof valve; 1329. Injection hole; 1330. Negative electrode post; 1331. Second main body; 1332. Second connecting section; 1333. Second extension; 1334. Second transition section; 1335. Second docking section; 1336. Second cavity; 134. First connecting piece; 1341. 1342. First through hole; 135. Second connecting piece; 1351. Second protrusion; 1352. Second through hole; 136. First upper plastic; 137. Second upper plastic; 138. Lower plastic; 1381. First through hole; 1382. Second through hole; 1383. First sealing ring; 1384. Second sealing ring; 14. Insulating film; 21. First tab; 22. Second tab; 101. First base Components; 102, First intermediate component; 103, First protrusion; 104, Second base component; 1041, First metal layer; 1042, Second metal layer; 105, Second intermediate component; 106, Second protrusion; 100, Battery pack; 110, Box body; 120, Battery module; 130, Bottom frame; 140, Box cover; 200, Energy storage cabinet; 210, Cabinet body; 300, Energy storage container; 310, Container. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this application to enable readers to better understand this application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in this application can be implemented. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0027] 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.

[0028] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0029] As energy sources become increasingly diverse, the importance of energy storage is also rising. Battery devices formed from individual battery cells are a widely used energy storage system; for example, lithium-ion battery devices are ubiquitous in industrial production and daily life. Lithium-ion batteries are widely used due to their high energy density, long cycle life per cell, high efficiency, and clean, pollution-free operation. Prismatic lithium-ion batteries, in particular, offer both high structural strength and high energy density. Furthermore, their relatively simple structure and ease of capacity expansion make them a crucial option for increasing energy density by improving the capacity of individual battery cells. A battery cell is a single battery cell or a single lithium-ion battery.

[0030] Currently, battery cells generally use a square encapsulation structure with a bottom shell and a top cover, with the top cover encapsulating the top of the cell assembly. Simultaneously, the positive and negative tabs of the cell assembly are folded onto the top of the bare cell and welded to the positive and negative connecting pieces, which are then welded to the top cover. The top cover houses the positive and negative terminals, explosion-proof valves, and other structures. The positive and negative terminals correspond to the positive and negative tabs of the cell assembly, allowing electrical energy to be introduced and output through the terminals. A cell assembly can consist of one or more bare cells, which are formed by winding or stacking positive and negative electrode sheets and a separator.

[0031] Currently, electrode post structures are classified into injection-molded, riveted, and welded types, mainly distinguished by their manufacturing processes. Injection-molded electrode post structures use injection molding to fit the plastic to the electrode post for fixation. Riveted electrode post structures use a riveted top cover to press the electrode post into a riveted aluminum block or upper plastic sheet with an interference fit; welding may or may not be used to fix the electrode post. Welded electrode post structures can be further divided into those where the electrode post is directly welded to the aluminum block, eliminating the riveting process, or those where the electrode post and welding ring are injection-molded together and then fixed to the plain aluminum sheet by welding the welding ring.

[0032] Each battery cell formed using these methods has its own characteristics: When a battery cell uses an injection-molded terminal structure, the injection-molded plastic has a larger bonding area with the terminal, ensuring a tight connection. At the same time, injection-molded plastic is less expensive, which helps save on material costs. When a riveted electrode structure is used in a battery cell, the resulting riveted structure has a high bonding force, which can ensure the connection strength of the electrode. When a welded terminal structure is used in a battery cell, the terminals can be assembled by welding, which is convenient. Furthermore, the terminals can form a stable connection interface after welding, ensuring the assembly effect of the terminals.

[0033] To ensure strong terminal connection while saving space in the terminal structure, freeing up internal space in the casing, increasing battery capacity, and thus improving the performance of the battery cell, some embodiments of this application provide a battery cell structure. The terminals and tabs in the battery cell are joined at the bottom, without sacrificing the weldable area at the top of the terminals. Simultaneously, aligning the bottoms of the terminals and tabs reduces the space occupied within the battery cell's encapsulation casing, allowing for more space to be used for cell assembly, thereby improving battery capacity.

[0034] The following is combined Figures 1 to 18 This application describes the structure of a battery cell provided in some embodiments.

[0035] like Figures 1 to 6 As shown, some embodiments of this application provide a battery cell 10 including a housing 11, a cell assembly 12, and a top cover assembly 13. The housing 11 has an opening 111. The cell assembly 12 is disposed inside the housing 11. The top cover assembly 13 includes a cover 131 connected to the housing 11 and closing the opening 111, a positive terminal 132 and a negative terminal 133 connected to the cover 131, a first connecting piece 134 connected to the positive terminal 132, and a second connecting piece 135 connected to the negative terminal 133.

[0036] The positive electrode post 132 includes a first main body 1321, a first connecting part 1322 protruding from the edge of the first main body 1321, and a first extension part 1323 extending from the edge of the first main body 1321 toward the inside of the housing 11. The first extension part 1323 includes a first transition part 1324 and a first mating part 1325 connected together. The first mating part 1325 is connected to a first connecting piece 134. The connection between the first mating part 1325 and the first connecting piece 134 is flush with the side near the cell assembly 12.

[0037] The negative terminal post 133 includes a second main body portion 1331, a second connecting portion 1332 protruding from the edge of the second main body portion 1331, and a second extension portion 1333 extending from the edge of the second main body portion 1331 toward the inside of the housing 11. The second extension portion 1333 includes a connected second transition portion 1334 and a second mating portion 1335. The second mating portion 1335 is connected to a second connecting piece 135. The connection between the second mating portion 1335 and the second connecting piece 135 is flush with the side near the cell assembly 12.

[0038] It should be noted that the parts in the positive terminal 132 and the parts in the negative terminal 133 are artificially divided for ease of explanation. In reality, there are no clear dividing lines between the parts, nor are they assembled from the parts during the manufacturing process.

[0039] The housing 11 is the part of the battery cell 10 that houses the battery cell assembly 12, and the housing 11 is hollow inside. The housing 11 and the cover 131 cooperate to form the encapsulation part of the battery cell 10. The housing 11 has high mechanical strength, providing protection for the internally installed components and preventing the battery cell assembly 12 from being affected by the external environment. The housing 11 and the cover 131 are connected to form the square outer shell of the battery cell 10. Figure 1 and Figure 2 The casing 11 is formed by four side walls enclosing the bottom wall to create an internal space with an opening 111 on one side. In practice, the casing 11 may have fewer than four or more side walls, forming a roughly square outer shell. The casing 11 and the cover 131 can be made of relatively lightweight aluminum. Additionally, the outer side of the battery cell 10 can be made of... Figure 3 The insulating film 14 shown is used to wrap the area and provides protection. The insulating film 14 can be a blue film.

[0040] The battery cell assembly 12 is disposed within the housing 11. The battery cell assembly 12 includes a positive electrode, a negative electrode, and a separator separating the positive and negative electrode. The positive electrode has a positive tab 121, and the negative electrode has a negative tab 122. The positive tab 121 and the positive terminal 132 are connected in the same current path, and the negative tab 122 and the negative terminal 133 are connected in the same current path. Figure 4The structure of the battery cell assembly 12 housed within the housing 11 in this embodiment is shown. Figure 5 A single bare battery cell is illustrated. This embodiment illustrates an example where the housing 11 contains two bare battery cells, i.e., the housing 11 contains a battery cell assembly 12 formed by two bare battery cells. In practice, the housing 11 may contain one or more bare battery cells.

[0041] The cell assembly 12 is the part of the battery cell 10 that works with the electrolyte to achieve electrochemical energy storage. During charging and discharging, lithium ions can move between the positive and negative electrode plates in the battery cell 10. The cell assembly 12 uses positive and negative electrode plates and a separator to form a bare cell through a winding process, or through a stacking process. In the bare cell, the top surface is the surface from which different tabs are led out; the positive electrode plate leads out the positive tab 121, and the negative electrode plate leads out the negative tab 122. Figure 4 and Figure 5 As shown, the positive electrode tab 121 and negative electrode tab 122, extending from the top surface of the bare battery cell, are separately located in two areas. The positive electrode tab 121 and negative electrode tab 122 are connected to different connecting pieces, which act as transitions to connect the positive electrode tab 121 to the positive terminal 132 and the negative electrode tab 122 to the negative terminal 133. In practice, the positive electrode tab 121 may have a gap between it and the top surface of the bare battery cell, or it may be attached to the top surface. Similarly, the negative electrode tab 122 may have a gap between it and the top surface of the bare battery cell, or it may be attached to the top surface.

[0042] The electrode structure is located at the top of the housing 11. To reduce the space occupied inside the housing 11, the electrode is usually folded. The top of the housing 11 refers to the part on the side where the opening 111 is located. The top of the housing 11 also has a top cover assembly 13, the structure of which is shown in Figure 6. The cover 131 in the top cover assembly 13 forms the base for connecting other components. Simultaneously, the cover 131 can be equipped with an explosion-proof valve structure 1313 and an explosion-proof valve patch 1314 to provide protection. Figure 7 As shown, the bottom side of the top cover assembly 13 is connected to the cell assembly 12, and the top side of the top cover assembly 13 is connected to the first plate 21 and the second plate 22. The protruding parts of the first plate 21 and the second plate 22 can be connected to the top cover assembly 13 of another battery cell 10. Figures 8 to 10 The mating structure between the top cover assembly 13 and the plate in this embodiment is illustrated. Figure 11 The mating structure formed at the positive electrode post 132 is shown. Figure 12 The mating structure formed at the negative electrode post 133 is shown. Figure 13 and Figure 14 The structure of the positive electrode post 132 is illustrated. Figure 15 and Figure 16The structure of the negative electrode post 133 is illustrated. From Figure 11 As can be seen, the bottom of the positive electrode post 132 is welded to the first connecting piece 134, forming a first weld M at the junction. The connection point between the first mating portion 1325 of the positive electrode post 132 and the first connecting piece 134 is flush with the side away from the cover 131. Figure 12 As can be seen, the bottom of the negative electrode post 133 is welded to the second connecting piece 135, forming a second weld N at the junction. The connection between the second mating part 1335 of the negative electrode post 133 and the second connecting piece 135 is flush with the side away from the cover 131. From Figure 11 It can also be seen that the top surface of the positive electrode post 132 is connected to the first electrode plate 21 by welding, forming a third weld P at the welding point. From Figure 12 It can also be seen that the top surface of the negative electrode post 133 is connected to the second electrode plate 22 by welding, forming a fourth weld Q at the welding point. Additionally, Figure 13 The boundary line between the first main body portion 1321 and the first connecting portion 1322 at the top of the positive electrode post 132 is shown by a vertical dotted line, and the boundary line between the first main body portion 1321 and the first extension portion 1323 is shown by a horizontal dotted line. Figure 15 The boundary line between the second main body 1331 and the second connecting part 1332 at the top of the negative electrode post 133 is shown by a vertical dotted line, and the boundary line between the second main body 1331 and the second extension 1333 is shown by a horizontal dotted line.

[0043] The first main body portion 1321 is the base portion of the positive electrode post 132, forming the main conductive portion of the positive electrode post 132. One side of the first main body portion 1321 is disposed inside the housing 11, which is connected to the positive electrode tab 121, and the other side of the first main body portion 1321 corresponds to the connection position of the first tab 21, which can realize the series or parallel connection of battery cells 10. The first connecting portion 1322 protrudes from the edge of the first main body portion 1321, and at least one side surface is flush with the surface of the first main body portion 1321. The first connecting portion 1322 is used to limit the mating position of the positive electrode post 132 on the cover 131, ensuring that the positive electrode post 132 can be partially located on one side of the cover 131, that is, the first connecting portion 1322 can be assembled to one side of the top surface of the cover 131 by the first upper plastic 136. The first connecting portion 1322 can be arranged in a manner that surrounds the first main body portion 1321, or it can be arranged in an arc shape on the outer surface of the first main body portion 1321. Alternatively, there can be multiple first main body portions 1321, which are distributed at different positions on the outer surface of the first main body portion 1321. The first extension portion 1323 is located on the back side of the first main body portion 1321 facing the housing 11. The first extension portion 1323 can cooperate with the first electrode post hole 1311 opened on the cover 131, so that the bottom of the positive electrode post 132 can enter the housing 11 and connect with the first connecting piece 134, and form a connection with the positive electrode tab 121 through the first connecting piece 134.

[0044] The first extension 1323 can be formed by an extrusion process. By applying pressure to deform the material, the material thickness is reduced, and the deformed part is used to form a protrusion, thereby saving material, reducing costs, and simplifying the pole manufacturing process. The first extension 1323 forms a protruding structure on one side of the first main body 1321, which can enter the first pole hole 1311 on the cover 131, and connect with the first connecting piece 134 in the area away from the bottom of the first main body 1321, thereby forming a stable connection with the cover 131.

[0045] The first transition portion 1324 is a portion of the first extension portion 1323 provided corresponding to the mating depth between the positive electrode post 132 and the cover 131. The first transition portion 1324 can form conductivity between the first main body portion 1321 and the bottom portion of the first extension portion 1323, i.e., the first mating portion 1325, so that current is transmitted on both sides of the positive electrode post 132. The first mating portion 1325 is the portion where the first extension portion 1323 mates with the first connecting piece 134. The first mating portion 1325 can pass through the cover 131 and reach the side of the cover 131 near the interior of the housing 11. The first connecting piece 134 is constrained by the lower plastic 138 on the side of the cover 131 near the interior of the housing 11. The first connecting piece 134 can mate with the side of the first mating portion 1325 passing through the first through hole 1381 of the lower plastic 138 and be fixed with the first mating portion 1325, thereby forming a connection with the positive electrode post 132. The first mating part 1325 and the first connecting piece 134 connected together are in a flat state on the side near the cell assembly 12. That is, on the side near the cell assembly 12, the connection between the first connecting piece 134 and the first mating part 1325 does not form an uneven or misaligned shape, and is basically in a state on the same plane, or in an aligned state where the difference does not exceed a certain threshold, such as a difference of no more than 0.5mm.

[0046] The second main body 1331 is the base part of the negative electrode post 133, forming the main conductive part of the negative electrode post 133. One side of the second main body 1331 is disposed inside the housing 11 corresponding to the negative electrode tab 122, and the other side of the second main body 1331 corresponds to the connection position of the second tab 22, which can realize the series or parallel connection of battery cells 10. The second connecting part 1332 protrudes from the edge of the second main body 1331, and at least one side surface is flush with the surface of the second main body 1331. The second connecting part 1332 is used to limit the mating position of the negative electrode post 133 on the cover 131, ensuring that the negative electrode post 133 can be in a state where a part is located on one side of the cover 131, that is, the second connecting part 1332 can be assembled to one side of the top surface of the cover 131 by the second upper plastic 137. The second connecting portion 1332 can be arranged in a manner that surrounds the second main body portion 1331, or it can be arranged in an arc shape on the outer surface of the second main body portion 1331. Alternatively, there can be multiple second main body portions 1331, which are distributed at different positions on the outer surface of the second main body portion 1331. The second extension portion 1333 is located on the back side of the second main body portion 1331 facing the housing 11. The second extension portion 1333 can cooperate with the second pole hole 1312 opened on the cover 131, so that the bottom of the negative pole 133 can enter the housing 11 and connect with the second connecting piece 135, and form a connection with the negative pole tab 122 through the second connecting piece 135.

[0047] The second extension 1333 can be formed by an extrusion process. By applying pressure to deform the material, the material thickness is reduced, and the deformed material is used to form a protrusion, thereby saving material, reducing costs, and simplifying the pole manufacturing process. The second extension 1333 forms a protruding structure on one side of the second main body 1331, which can enter the second pole hole 1312 on the cover 131, and connect with the second connecting piece 135 in the area away from the bottom of the second main body 1331, thereby forming a stable connection with the cover 131.

[0048] The second transition portion 1334 is a portion of the second extension portion 1333 provided corresponding to the mating depth between the negative electrode post 133 and the cover 131. The second transition portion 1334 can form conductivity between the second main body portion 1331 and the bottom portion of the second extension portion 1333, i.e., the second mating portion 1335, so that current can be transmitted on both sides of the negative electrode post 133. The second mating portion 1335 is the portion where the second extension portion 1333 mates with the second connecting piece 135. The second mating portion 1335 can pass through the cover 131 and reach the side of the cover 131 near the interior of the housing 11. The second connecting piece 135 is restricted to the side of the cover 131 near the interior of the housing 11 by the lower plastic 138. The second connecting piece 135 can mate with the side of the second mating portion 1335 passing through the second through hole 1382 of the lower plastic 138 and be fixed with the second mating portion 1335, thereby forming a connection with the negative electrode post 133. The second mating part 1335 and the second connecting piece 135 connected together are in a flush state on the side near the cell assembly 12. That is, on the side near the cell assembly 12, the connection between the second connecting piece 135 and the second mating part 1335 does not form an uneven or misaligned shape, and is basically in a state on the same plane, or in an aligned state where the difference does not exceed a certain threshold, such as a difference of no more than 0.5mm.

[0049] The battery cell 10 provided in some embodiments of this application employs a positive electrode post 132 and a negative electrode post 133 with protruding structures at the bottom. The protruding portion of the positive electrode post 132, i.e., the first mating portion 1325, can enter the interior of the housing 11 and mate with the first connecting piece 134. The protruding portion of the negative electrode post 133, i.e., the second mating portion 1335, can enter the interior of the housing 11 and mate with the second connecting piece 135. When different electrodes are connected to corresponding connecting pieces, the connection points between the electrodes and the connecting pieces can be flush with the side closest to the cell assembly 12, thereby aligning the connecting piece and the electrode post in a close position. By adopting the bottom mating form between the electrode post and the tab connecting piece, the solderable area at the top of the electrode post is not lost. At the same time, aligning the bottom of the electrode post and the tab connecting piece reduces the space occupied inside the battery cell 10's encapsulation shell, thereby utilizing more space for the arrangement of the cell assembly 12, which is beneficial for increasing battery capacity and improving the working performance of the battery cell 10.

[0050] In some embodiments, the first extension 1323 may be arranged in a ring shape, the first connecting piece 134 may be arranged around the first mating portion 1325, and / or the second extension 1333 may be arranged in a ring shape, the second connecting piece 135 may be arranged around the second mating portion 1335.

[0051] In other words, the first extension 1323 is arranged around the central axis of the positive electrode post 132. When the positive electrode post 132 has a regular shape, the direction of the central axis is the direction of the axis of symmetry of the positive electrode post 132. When the positive electrode post 132 has an irregular shape, the direction of the central axis is parallel to... Figure 8 The direction indicated by the middle arrow J. The first connecting piece 134 is connected to the periphery of the first mating part 1325. The first connecting piece 134 has a first through hole 1342, and the first mating part 1325 mates with the wall of the first through hole 1342.

[0052] By arranging the first extension 1323 in a ring shape, it is ensured that it forms a mating portion with the first connecting piece 134 throughout the entire circumferential direction, thereby ensuring the connection effect between the first mating portion 1325 and the first connecting piece 134. At the same time, it ensures the structural strength of the protruding portion of the positive electrode post 132.

[0053] The second extension 1333 of the negative electrode post 133 can also be arranged in a ring shape, that is, the second extension 1333 is arranged around the central axis of the negative electrode post 133. The second connecting piece 135 is connected to the periphery of the second mating part 1335, and the second connecting piece 135 has a second through hole 1352, and the second mating part 1335 mates with the hole wall of the second through hole 1352.

[0054] By arranging the second extension 1333 in a ring shape, it is ensured that it forms a mating portion with the second connecting piece 135 throughout the entire circumferential direction, thereby ensuring the connection effect between the second mating portion 1335 and the second connecting piece 135. At the same time, it ensures the structural strength of the protruding portion of the negative electrode post 133.

[0055] like Figure 14 As shown, a first cavity 1326 is formed on the inner side of the first extension 1323 away from the first connecting piece 134.

[0056] The first cavity 1326 is located inside the first extension 1323, meaning the inner side of the first extension 1323 is hollow, and the first extension 1323 has a certain wall thickness. The first cavity 1326 is the area where the cavity is formed at the bottom of the positive electrode post 132, which can reduce the material used in the positive electrode post 132 and reduce the manufacturing cost of the electrode post structure.

[0057] like Figure 16As shown, a second cavity 1336 is formed on the inner side of the second extension 1333 away from the second connecting piece 135.

[0058] The second cavity 1336 is located inside the second extension 1333, that is, the inner side of the second extension 1333 is hollow. The second extension 1333 has a certain wall thickness. The second cavity 1336 is the area where the cavity is formed at the bottom of the negative electrode post 133, which can reduce the material used in the negative electrode post 133 and reduce the manufacturing cost of the post structure.

[0059] In addition, the empty portion formed by the first cavity 1326 and the second cavity 1336 can also form a reserved space to provide a space for the electrolyte filled in the shell 11 and the generated gas, thereby reducing the pressure on the shell 11.

[0060] In some embodiments, in the first direction ( Figure 8 In the direction indicated by the middle arrow I, the size of the first transition portion 1324 can be larger than the size of the first mating portion 1325, and the size of the second transition portion 1334 can be larger than the size of the second mating portion 1335.

[0061] The first direction is the direction that intersects with the thickness direction of the cover 131, and the thickness direction of the cover 131 is parallel to the second direction. Figure 8 (The direction indicated by the middle arrow J). That is to say, the first direction can be perpendicular to the second direction, or the first direction can form an acute or obtuse angle with the second direction. For example, the angle between the first and second directions can be 70°, 80°, 90°, or 100°.

[0062] The dimension of the first transition portion 1324 in the first direction can measure the cross-sectional size of the first transition portion 1324, and the dimension of the first mating portion 1325 in the first direction can measure the cross-sectional size of the first mating portion 1325. By making the dimension of the first transition portion 1324 in the first direction larger than the dimension of the first mating portion 1325 in the first direction, a stepped structure can be formed on the first extension portion 1323 to facilitate the assembly of the first sealing ring 1383 and the positioning of the first connecting piece 134.

[0063] like Figure 13 and Figure 14 As shown, the junction of the first transition portion 1324 and the first mating portion 1325 has a tapered side surface. This tapered side surface facilitates the assembly of the first sealing ring 1383. Simultaneously, the side of the first connecting piece 134 closest to the cover 131 can abut against the tapered side surface. This utilizes the dimensional difference between the first transition portion 1324 and the first mating portion 1325 to position the first connecting piece 134, facilitating the connection and assembly between the first connecting piece 134 and the first mating portion 1325.

[0064] The dimension of the second transition portion 1334 in the first direction can measure the cross-sectional size of the second transition portion 1334, and the dimension of the second mating portion 1335 in the first direction can measure the cross-sectional size of the second mating portion 1335. By making the dimension of the second transition portion 1334 in the first direction larger than the dimension of the second mating portion 1335 in the first direction, a stepped structure can be formed on the second extension portion 1333 to facilitate the assembly of the second sealing ring 1384 and the positioning of the second connecting piece 135.

[0065] like Figure 15 and Figure 16 As shown, the junction of the second transition portion 1334 and the second mating portion 1335 has a tapered side surface. This tapered side surface facilitates the assembly of the second sealing ring 1384. Simultaneously, the side of the second connecting piece 135 closest to the cover 131 can abut against the tapered side surface. This utilizes the dimensional difference between the second transition portion 1334 and the second mating portion 1335 to position the first connecting piece 134, facilitating the connection and assembly between the second connecting piece 135 and the second mating portion 1335.

[0066] In some embodiments, the second main body portion 1331 and the second transition portion 1334 may include a first metal layer 1041 and a second metal layer 1042, wherein the first metal layer 1041 and the second metal layer 1042 are made of different materials, and the second mating portion 1335 and the second connecting portion 1332 are made of different materials.

[0067] In other words, the negative electrode post 133 is made of at least two materials. The first metal layer 1041 corresponds to the upper structure of the negative electrode post 133, and the second metal layer 1042 corresponds to the lower structure of the negative electrode post 133. The bottom of the negative electrode post 133 is used to connect with the second connecting piece 135, and the top of the negative electrode post 133 is used to connect with the second current collector 22 for the battery cell 10. In practice, since the negative current collector of the bare cell inside the battery cell 10 is made of copper foil, using copper for the negative electrode post 133 can ensure the performance of the bare cell inside the battery cell. However, pure copper has the disadvantages of being heavy and costly. Therefore, the negative electrode post 133 is designed as a copper-aluminum composite post, and aluminum is used to connect the external current collector to solve the problems of heavy weight and high cost of the negative electrode post structure made of pure copper.

[0068] like Figure 14 As shown, a first chamfer E may be provided on the inner side of the first mating part 1325 away from the first connecting piece 134.

[0069] The inner side of the first mating portion 1325 corresponds to the first cavity 1326. By providing a first chamfer E on the inner side of the first mating portion 1325, the first chamfer E ensures that the inner edge of the first mating portion 1325 has no sharp shape, which is beneficial for a smooth transition during processing and reduces phenomena such as microcracks. At the same time, it also helps to reduce the material used in the positive electrode post 132 and reduce the manufacturing cost of the positive electrode post 132.

[0070] like Figure 16 As shown, a second chamfer F may be provided on the inner side of the second docking portion 1335 away from the second connecting piece 135.

[0071] The inner side of the second mating portion 1335 corresponds to the second cavity 1336. By providing a second chamfer F on the inner side of the second mating portion 1335, the inner edge of the second mating portion 1335 is free of sharp shapes, which is beneficial for a smooth transition during processing and reduces phenomena such as microcracks. At the same time, it also helps to reduce the material used in the negative electrode post 133 and reduce the manufacturing cost of the negative electrode post 133.

[0072] In some embodiments, the first main body portion 1321 and / or the second main body portion 1331 may be provided with an explosion-proof valve 1327 or a liquid injection hole 1328.

[0073] In other words, an explosion-proof valve 1327 or a liquid injection hole 1328 can be installed in the first main body portion 1321 of the positive electrode post 132 or the second main body portion 1331 of the negative electrode post 133 to achieve structural integration and improve the safety of the battery cell 10. The explosion-proof valve 1327 can promptly release pressure when thermal runaway occurs in the battery cell 10, allowing the high-pressure gas inside the casing 11 to be discharged to the outside, thereby preventing the battery cell 10 from exploding. The explosion-proof valve 1327 can be a pressure relief valve or an explosion-proof plate. For example, a separate pressure relief valve can be installed on the first main body portion 1321 of the positive electrode post 132, or the first main body portion 1321 of the positive electrode post 132 can be made into a plate with grooves or notches. To avoid affecting the first extension portion 1323, the explosion-proof valve can be located in the middle region of the first main body portion 1321.

[0074] Figure 17 Taking the positive terminal 132 as an example, an explosion-proof valve 1327 is shown on the positive terminal 132. Figure 18 Taking the positive electrode post 132 as an example, the illustration shows the liquid injection hole 1328 provided on the positive electrode post 132. In actual situations, an explosion-proof valve 1327 or a liquid injection hole 1328 can also be provided on the negative electrode post 133.

[0075] In addition, in the second direction, the minimum size of the first main body portion 1321 and / or the second main body portion 1331 can be 0.3mm to 1mm.

[0076] To facilitate the installation of structures such as injection holes on the first main body portion 1321 of the positive electrode post 132 or the second main body portion 1331 of the negative electrode post 133, the first main body portion 1321 or the second main body portion 1331 can be thinned. Specifically, the minimum thickness H1 of the first main body portion 1321 or the second main body portion 1331 in the second direction can be controlled within the range of 0.3mm to 1mm, for example, 0.3mm, 0.5mm, 0.7mm, 0.9mm, or 1mm. This avoids insufficient structural strength due to excessive thickness of the first main body portion 1321 or the second main body portion 1331, which would affect the normal use of the electrode post structure. It also avoids difficulties in installing structures such as injection holes due to excessive thickness of the first main body portion 1321 or the second main body portion 1331, allowing for the integration of structures such as the explosion-proof valve 1327 and the injection hole 1328 onto the electrode post structure.

[0077] In some embodiments, the first connecting piece 134 may be provided with a first protrusion 1341, the first protrusion 1341 extending toward the second connecting piece 135, and the second connecting piece 135 is provided with a second protrusion 1351, the second protrusion 1351 extending toward the first connecting piece 134.

[0078] The first protrusion 1341 is a lug structure formed on the first connecting piece 134. The first protrusion 1341 can serve as a part of the first connecting piece 134 that connects to the positive electrode tab 121, facilitating the connection between the first connecting piece 134 and the positive electrode tab 121. Two first protrusions 1341 can be provided so that they can respectively cooperate with the positive electrode tabs 121 of the two battery cell assemblies 12.

[0079] The second protrusion 1351 is a lug structure formed on the second connecting piece 135. The second protrusion 1351 can serve as a part on the second connecting piece 135 that connects to the negative electrode tab 122, facilitating the connection between the second connecting piece 135 and the negative electrode tab 122. Two second protrusions 1351 can be provided so that they can respectively cooperate with the negative electrode tabs 122 of the two battery cell assemblies 12.

[0080] In some embodiments, in the second direction, the dimensions of the first mating portion 1325 and / or the second mating portion 1335 can be 0.3mm to 3mm.

[0081] The dimension of the first mating portion 1325 in the second direction corresponds to the extension dimension L1 of the first mating portion 1325, and the dimension of the second mating portion 1335 in the second direction corresponds to the extension dimension L2 of the second mating portion 1335. By controlling the extension dimension L1 of the first mating portion 1325 or the extension dimension L2 of the second mating portion 1335, it is possible to avoid the mating portion of the terminal post extending too long, which would increase the space occupied and affect the battery capacity. It is also possible to avoid the mating portion of the terminal post extending too short, which would result in a small mating area with the connecting piece and affect the connection strength between the mating portion of the terminal post and the connecting piece.

[0082] In practice, in the second direction, the extension dimensions of the first mating portion 1325 and / or the second mating portion 1335 can be 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm or 3mm.

[0083] Furthermore, the extension dimension L3 of the first extension 1323 and the extension dimension L4 of the second extension 1333 can be 1.5mm to 8mm, for example, 1.5mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, or 8mm. The wall thickness of the first extension 1323 and the second extension 1333 can be 2mm to 8mm, for example, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, or 8mm. The maximum distance between two points on the outer surface of the first extension 1323 can be less than the maximum distance between two points on the outer surface of the first main body 1321 (4mm to 12mm), and the maximum distance between two points on the outer surface of the second extension 1333 can be less than the maximum distance between two points on the outer surface of the second main body 1331 (4mm to 12mm). That is, the size difference between the top and bottom of the positive electrode post 132 and the size difference between the top and bottom of the negative electrode post 133 can be controlled within the range of 4mm to 12mm.

[0084] In some embodiments, in the second direction, the dimensions of the first main body portion 1321 and / or the second main body portion 1331 can be 1mm to 5mm.

[0085] The dimension of the first main body portion 1321 in the second direction corresponds to the thickness dimension H2 of the first main body portion 1321, and the dimension of the second main body portion 1331 in the second direction corresponds to the thickness dimension H3 of the second main body portion 1331. By controlling the dimensions of the first main body portion 1321 and / or the second main body portion 1331, material waste and increased costs due to excessive thickness of the main body portion of the pole post can be avoided, as can low overall structural strength of the pole post due to insufficient thickness of the main body portion of the pole post, thus avoiding affecting the normal use of the pole post structure.

[0086] In practice, in the second direction, the thickness of the first main body portion 1321 and / or the second main body portion 1331 can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm.

[0087] In some embodiments, the surface area of ​​the positive electrode post 132 and / or the negative electrode post 133 on the side away from the cell assembly 12 is 50 mm². 2 ~1000mm 2 .

[0088] The surfaces of the positive electrode post 132 and the negative electrode post 133 on the side away from the cell assembly 12 are the connection surfaces of the external electrode pads. By controlling the surface area of ​​the positive electrode post 132 and / or the negative electrode post 133 on the side away from the cell assembly 12, the connection strength between the external electrode pads and the electrode post structure in the battery cell 10 can be ensured. This can avoid affecting the welding process of the electrode pads due to the small connection surface area of ​​the electrode post structure, thus avoiding affecting the connection effect of the electrode pads. It can also avoid material waste and increased electrode post costs due to the large connection surface area of ​​the electrode post structure.

[0089] In practice, the surface area S1 of the positive terminal 132 away from the cell assembly 12 and / or the surface area S2 of the negative terminal 133 away from the cell assembly 12 can be 50 mm². 2 100mm 2 200mm 2 300mm 2 400mm 2 500mm 2 600mm 2 700mm 2 Or 800mm 2 900mm 2 Or 1000mm 2 .

[0090] In some embodiments, the projected outline shape of the positive electrode post 132 and / or the negative electrode post 133 along the second direction on the cover 131 is circular, square, rectangular or elliptical.

[0091] In other words, the outer contour shape of the positive electrode post 132 and / or the negative electrode post 133 can be a regular circle, square, rectangle or ellipse, or it can be a polygonal shape such as a pentagon or octagon, or a racetrack shape. Regular shapes can simplify the electrode post structure, reduce the manufacturing difficulty of the electrode post structure, and ensure the overall strength of the electrode post structure.

[0092] In this embodiment, the outline shape of the first connecting part 1322 at the top of the positive electrode post 132 is consistent with the outline shape of the first extension part 1323 at the bottom, both being racetrack-shaped. Setting it as a racetrack shape can make full use of the arrangement space on the cover 131, ensuring that the electrode post can form a tight connection with the connecting piece and the bar piece.

[0093] In practice, the external contour shape of the positive electrode post 132 and / or the negative electrode post 133 can also be an irregular shape.

[0094] Some embodiments of this application also provide a method for preparing a single battery cell, such as... Figure 19 As shown, the preparation method of a single battery cell includes the following steps: Step S110: Provide a housing with an opening.

[0095] The casing is the foundation for housing the battery cell assembly and forms the main part of the battery cell's encapsulation. An opening at the top of the casing allows the battery cell assembly to be installed. This opening is located on the opposite side of the bottom wall of the casing. The area of ​​the bottom wall can be larger or smaller than the area of ​​the side wall, meaning the battery cell assembly can be installed horizontally or vertically along the opening. The casing can be made of lightweight and structurally strong aluminum.

[0096] Step S120: Place the battery cell assembly into the housing.

[0097] A battery cell assembly includes a positive electrode, a negative electrode, and a separator. Different electrodes and separators are formed into a whole using a winding or stacking process. After the battery cell's cover is assembled, electrolyte is injected into the casing to allow the electrolyte to integrate with the battery cell assembly and undergo a formation process to form a battery cell with charge and discharge capabilities.

[0098] Step S130: Provide a positive electrode post and a negative electrode post. The positive electrode post includes a first main body portion, a first connecting portion protruding from the edge of the first main body portion, and a third connecting portion extending from the edge of the first main body portion in a third direction. Figure 25 and Figure 26 The first extension portion extends in the direction indicated by the middle arrow K. The first extension portion includes a connected first transition portion and a first mating portion. The negative electrode post includes a second main body portion, a second connecting portion protruding from the edge of the second main body portion, and a portion extending from the edge of the second main body portion along a fourth direction (…). Figure 32 and Figure 33 The second extension (in the direction indicated by the middle arrow L) extends in the direction of the second extension, which includes a connected second transition portion and a second mating portion.

[0099] The positive and negative terminals are crucial components that connect the battery cell assembly and enable current transfer. The positive terminal can be made of the same material as the positive electrode structure and the electrode plate structure of the battery cell assembly, while the bottom of the negative terminal can be made of the same material as the negative electrode structure of the battery cell assembly, and the top can be made of the same material as the electrode plate structure.

[0100] Aluminum or aluminum alloys, which are insoluble in non-aqueous electrolytes at the positive electrode potential, are suitable materials for manufacturing the positive electrode post. Conductive materials such as copper, which do not alloy with the negative electrode active material, are more commonly used for manufacturing the negative electrode post. When battery cells are interconnected to form a battery pack, a current collector (or ferrule) is welded to either the positive or negative electrode post. Since the ferrule is usually made of a single material, and aluminum has a lower melting point and higher specific heat capacity than copper, it is not easy to weld copper and aluminum together using ultrasonic welding, laser welding, or similar methods. Therefore, the welding surfaces of the positive and negative electrode posts are made of the same material as the ferrule. Typically, the ferrule is made of lower-cost aluminum, and the positive electrode post is also made of aluminum. The negative electrode post can be made of a copper-aluminum composite material, with the bottom of the negative electrode post welded to the connecting piece being made of copper, and the top of the negative electrode post welded to the ferrule being made of aluminum.

[0101] Step S140: Pass the first mating part of the positive electrode post through the cover, weld the first connecting piece to the first mating part, and make the mating point of the first connecting piece and the first mating part flush with the side away from the cover; and pass the second mating part of the negative electrode post through the cover, weld the second connecting piece to the second mating part, and make the mating point of the second connecting piece and the second mating part flush with the side away from the cover.

[0102] The cover and casing work together to form the encapsulation shell of the battery cell. Different terminals work with the cover to form a top cover assembly, which includes a terminal structure, an explosion-proof structure, and a liquid filling structure. The first mating part of the positive terminal passes through the first terminal hole in the cover and connects to the first connecting piece. After the first connecting piece is basically flush with the first mating part, the junction can be butt-welded to fix the first connecting piece and the first mating part. Similarly, the negative terminal is fixed to the second connecting piece by butt welding.

[0103] In addition, upper plastic is provided between the first connecting part of the positive terminal and the cover, and between the second connecting part of the negative terminal and the cover, to insulate the terminal structure from the cover and prevent short circuits caused by using a metal cover. Lower plastic can be provided between the first connecting piece and the cover, and between the second connecting piece and the cover, for insulation. A sealing ring can also be provided within the lower plastic inner ring to ensure a tight seal.

[0104] The first connecting piece is used to connect with the positive electrode tab of the battery cell assembly, and the second connecting piece is used to connect with the negative electrode tab of the battery cell assembly.

[0105] Step S150: Weld the cover to the shell and seal the opening.

[0106] After the cover and casing are welded together, the assembly of the various parts of the battery cell is complete. The cover can be sealed to the opening of the casing to ensure the airtightness of the casing. Then, electrolyte can be injected into the casing, and a formation process can be performed to form a battery cell that can function normally.

[0107] In some embodiments, providing the positive electrode post in step S130 may include the following steps: Step S1311: Stamping to form the first basic component.

[0108] The first basic component is formed by stamping the supplied material. For the positive electrode post, aluminum material with lower cost can be used for manufacturing. Figure 20 The first base component formed by stamping is illustrated. The first base component 101 formed by stamping is similar in outline to the positive electrode post to be manufactured, so that the positive electrode post can be formed in the subsequent extrusion and shearing processes.

[0109] Step S1312: Press the periphery of the first base component and squeeze the central area of ​​the first base component to form a first intermediate component with a first protrusion on one side.

[0110] The first basic component is extruded using cold heading, which forces some of the material to undergo plastic deformation, forming protruding parts. Figure 21 and Figure 22 The diagram illustrates the first intermediate part formed by extrusion. The first protrusion 103 of the first intermediate part 102 can form a portion that mates with the first connecting piece. By using a cold heading process, the thickness can be reduced while forming the protrusion, thereby saving material and avoiding the increased cost of pole manufacturing caused by cutting.

[0111] Step S1313: Cut the edges of the first intermediate part and remove the outer part of the first protrusion along the first preset position to form a positive electrode post including a first main body, a first connecting part and a first extension.

[0112] After the first intermediate part is formed, some material can be removed to form the final positive electrode post, so that the protruding part can enter the first electrode post hole opened on the cover and ensure that the unremoved part can be restricted to one side of the cover.

[0113] Figure 23 and Figure 24 The first intermediate part after edge trimming is illustrated, wherein, Figure 24The first preset position is illustrated. After the first intermediate part 102 is edge-cut, material can be removed along the first preset position X, ultimately forming... Figure 25 and Figure 26 The positive electrode post 132 is shown. The positive electrode post 132 includes a first main body portion 1321 and a first connecting portion 1322 located at the top, with the first connecting portion 1322 surrounding the periphery of the first main body portion 1321. The positive electrode post 132 also includes a first extension portion 1323 located at the bottom. The portion of the first extension portion 1323 connected to the first main body portion 1321 forms a first transition portion 1324, while the portion of the first extension portion 1323 away from the first main body portion 1321 forms a first mating portion 1325, which can be butt-welded to the first connecting piece.

[0114] In some embodiments, providing the negative electrode post in step S130 may include the following steps: Step S1321: Stamping to form the second base component.

[0115] The second basic component is formed by stamping of incoming materials. For the negative electrode post, copper-aluminum composite material can be used for manufacturing. Figure 27 The second base component formed by stamping is illustrated. The outline of the stamped second base component 104 is similar to that of the fabricated negative electrode post, so that the negative electrode post can be formed subsequently through extrusion and shearing processes. The second base component 104 includes a first metal layer 1041 formed of aluminum material on the upper layer and a second metal layer 1042 formed of copper material on the lower layer. That is, a sheet metal material of a certain shape and size is stamped from copper-aluminum composite sheet metal material as the initial material for the negative electrode post.

[0116] Step S1322: Press the periphery of the second base component and squeeze the central area of ​​the second base component to form a second intermediate component with a second protrusion on one side.

[0117] The second basic component is extruded by cold heading, which presses the surrounding plates and squeezes the middle area, forcing some of the material to undergo plastic deformation and form a protruding part. Figure 28 and Figure 29 The second intermediate part formed by extrusion is illustrated. The second protrusion 106 of the second intermediate part 105 can form a part that mates with the second connecting piece. By using a cold heading process, the thickness can be reduced while forming the protrusion, thereby saving material and avoiding the increase in pole manufacturing cost caused by cutting.

[0118] Step S1323: Cut the edges of the second intermediate part and remove the outer part of the second protrusion along the second preset position to form a negative electrode post including the second main body, the second connecting part and the second extension part.

[0119] After the second intermediate part is formed, some material can be removed to form the final negative electrode post, so that the protruding part can enter the second electrode post hole opened on the cover and ensure that the unremoved part can be restricted to one side of the cover.

[0120] Figure 30 and Figure 31 The second intermediate part after edge trimming is illustrated, wherein, Figure 31 The second preset position is illustrated. After edge shearing of the second intermediate part 105, material can be removed along the second preset position Y, ultimately forming... Figure 32 and Figure 33 The negative electrode post is shown. The negative electrode post 133 includes a second main body portion 1331 and a second connecting portion 1332 located at the top, with the second connecting portion 1332 surrounding the periphery of the second main body portion 1331. The negative electrode post 133 also includes a second extension portion 1333 located at the bottom, with the portion of the second extension portion 1333 connecting to the second main body portion 1331 forming a second transition portion 1334, and the portion of the second extension portion 1333 away from the second main body portion 1331 forming a second mating portion 1335, which can be butt-welded to the second connecting piece.

[0121] After processing, the terminal post structure can be combined with other components to form a complete top cover assembly. The terminal post is sequentially passed through the upper plastic, the aluminum sheet terminal post hole, the sealing ring, and the lower plastic. Then, the connecting piece is pressed against the sealing ring and welded to the terminal post, effectively freeing up space inside the housing cavity. Direct welding of the connecting piece to the terminal post eliminates the need for a base plate in the height direction of the battery cell, and also saves the base plate component. Welding between the terminal post and the connecting piece can be achieved through ultrasonic welding or laser welding.

[0122] Top cover assemblies with terminals and connecting pieces are suitable for large-capacity battery cells, such as long-term energy storage devices with low overcurrent requirements. Of course, in practical applications, they are not limited to long-term energy storage devices.

[0123] Because the top surface of the electrode post, i.e. the welding surface of the electrode between two adjacent battery cells, has no metal welding or riveting joint surface, the weldable area can account for more than 75%. The weldable area is larger than the welding area of ​​the electrode post on a traditional top cover. Because traditional top covers have a large proportion of plastic or welding on the outer surface, the weldable area of ​​the electrode is small, accounting for no more than 50%.

[0124] The positive electrode post can also be made into an explosion-proof valve or welded explosion-proof valve to achieve integrated protective structure. An explosion-proof valve can be installed in the first main body of the positive electrode post to improve the safety of the battery cell. The explosion-proof valve can promptly relieve pressure in the event of thermal runaway in the battery cell, allowing high-pressure gas inside the casing to escape to the outside, thus preventing the battery cell from exploding. The explosion-proof valve can be a pressure relief valve or an explosion-proof plate. For example, a separate pressure relief valve can be installed on the first main body of the positive electrode post, or the first main body of the positive electrode post can be made into a plate with grooves or notches. To avoid affecting the first extension, the explosion-proof valve can be located in the middle area of ​​the first main body. Figure 17 A diagram illustrating the installation of an explosion-proof valve on the positive terminal is provided.

[0125] The positive electrode post can also have an injection port to achieve integrated electrolyte filling structure. The injection port can be made in the first main body of the positive electrode post to inject electrolyte into the casing of the battery cell through the positive electrode post. Figure 18 A schematic diagram of the injection hole on the positive electrode post is provided.

[0126] In practice, an explosion-proof valve or a liquid injection port can also be installed on the negative terminal.

[0127] The battery cells provided in this application can be widely used in battery fields requiring high energy density and long cycle life, including high-end electric vehicle battery systems, portable electronic devices, and large-scale energy storage power stations. The battery cells provided in this application can achieve large-capacity energy storage, comprehensively improving energy density, cycle life, and safety performance. They can meet the needs of long-term energy storage, achieving 4 hours or more of long-term energy storage, for example, in energy storage scenarios of 5 hours, 6 hours, and 8 hours. Long-term energy storage refers to the ability to continuously discharge at rated power for 4 hours or even longer, or to achieve large-scale, low-cost energy storage for several days or months.

[0128] Some embodiments of this application also provide a battery device, which includes the battery cell described above, or a battery cell manufactured by the method described above for preparing the battery cell.

[0129] Battery devices include one or more of the following: battery modules, battery packs, and energy storage batteries.

[0130] like Figure 34 and Figure 35As shown, the battery pack 100 includes a housing 110 and multiple battery modules 120 located within the housing 110. Each battery module 120 includes multiple individual battery cells 10. The housing 110 includes a bottom frame 130 and a cover 140. The bottom frame 130 defines the position of the battery modules 120, and the cover 140 accommodates the battery modules 120. In practice, the number of battery modules 120 within the housing 110 can be one or more, and the housing 110 can also be formed with the battery modules housed at the bottom.

[0131] Some embodiments of this application also provide an energy storage device, which includes the battery device described above, and the battery device is used to store electrical energy.

[0132] Energy storage devices include, but are not limited to, residential energy storage cabinets, commercial energy storage cabinets, energy storage containers, energy storage racks, energy storage power stations, energy storage battery packs, or portable energy storage systems. Energy storage devices may also include energy management systems (EMS), battery management systems (BMS), and power conversion systems (PCS).

[0133] Figure 36 The diagram illustrates the energy storage cabinet 200, which uses a cabinet 210 to house the battery device. Figure 37 The diagram illustrates the energy storage container, with container 300 using container 310 to house the battery device.

[0134] Some embodiments of this application also provide an electrical device, which includes the battery device described above, and the battery device is used to provide electrical energy.

[0135] Electrical devices include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0136] Those skilled in the art will understand that the above embodiments are specific implementations of this application, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of this application.

Claims

1. A battery cell, characterized in that, include: The casing has an opening; The battery cell assembly is disposed within the housing; The top cover assembly includes a cover body connected to the housing and closing the opening, a positive terminal and a negative terminal connected to the cover body, a first connecting piece connected to the positive terminal, and a second connecting piece connected to the negative terminal. The positive electrode post includes a first main body, a first connecting part protruding from the edge of the first main body, and a first extension part extending from the edge of the first main body toward the inside of the housing. The first extension part includes a first transition part and a first mating part connected together. The first mating part is connected to the first connecting piece, and the connection between the first mating part and the first connecting piece is flush with the side close to the cell assembly. The negative electrode post includes a second main body, a second connecting part protruding from the edge of the second main body, and a second extension part extending from the edge of the second main body toward the inside of the housing. The second extension part includes a connected second transition part and a second mating part. The second mating part is connected to the second connecting piece, and the connection between the second mating part and the second connecting piece is flush with the side near the cell assembly.

2. The battery cell according to claim 1, characterized in that, The first extension is arranged in a ring shape, the first connecting piece is arranged around the first mating portion, and / or the second extension is arranged in a ring shape, the second connecting piece is arranged around the second mating portion.

3. The battery cell according to claim 1 or 2, characterized in that, The first extension has a first cavity formed on the inner side away from the first connecting piece, and the second extension has a second cavity formed on the inner side away from the second connecting piece.

4. The battery cell according to claim 1, characterized in that, In a first direction, the size of the first transition portion is larger than the size of the first mating portion, and the size of the second transition portion is larger than the size of the second mating portion.

5. The battery cell according to claim 1, characterized in that, The second main body and the second transition portion include a first metal layer and a second metal layer, the first metal layer and the second metal layer are made of different materials, and the second mating portion and the second connecting portion are made of different materials.

6. The battery cell according to claim 1, characterized in that, The first mating portion has a first chamfer on its inner side away from the first connecting piece, and the second mating portion has a second chamfer on its inner side away from the second connecting piece.

7. The battery cell according to claim 1, characterized in that, The first main body and / or the second main body are provided with an explosion-proof valve or a liquid injection hole.

8. The battery cell according to claim 7, characterized in that, In the second direction, the minimum size of the first main body portion and / or the second main body portion is 0.3mm to 1mm.

9. The battery cell according to claim 1, characterized in that, The first connecting piece is provided with a first protrusion, which extends toward the second connecting piece. The second connecting piece is provided with a second protrusion, which extends toward the first connecting piece.

10. The battery cell according to claim 1, characterized in that, In the second direction, the dimensions of the first mating portion and / or the second mating portion are 0.3mm to 3mm.

11. The battery cell according to claim 1, characterized in that, In the second direction, the dimensions of the first main body portion and / or the second main body portion are 1mm to 5mm.

12. The battery cell according to claim 1, characterized in that, The surface area of ​​the positive electrode post and / or the negative electrode post on the side away from the cell assembly is 50 mm². 2 ~1000mm 2 .

13. The battery cell according to claim 1, characterized in that, The projection outline of the positive electrode post and / or the negative electrode post on the cover along the second direction is circular, square, rectangular or elliptical.

14. A method for preparing a single battery cell, characterized in that, include: A housing is provided, the housing having an opening; Place the battery cell assembly into the housing; A positive electrode post and a negative electrode post are provided. The positive electrode post includes a first main body, a first connecting part protruding from the edge of the first main body, and a first extension part extending from the edge of the first main body along a third direction. The first extension part includes a first transition part and a first mating part connected together. The negative electrode post includes a second main body, a second connecting part protruding from the edge of the second main body, and a second extension part extending from the edge of the second main body along a fourth direction. The second extension part includes a second transition part and a second mating part connected together. The first mating portion of the positive electrode post is passed through the cover, and the first connecting piece is butt-welded to the first mating portion, so that the mating point of the first connecting piece and the first mating portion is flush with the side away from the cover. The second mating portion of the negative electrode post is passed through the cover, and the second connecting piece is butt-welded to the second mating portion, so that the mating point of the second connecting piece and the second mating portion is flush with the side away from the cover. The cover is welded to the housing and the opening is sealed.

15. The method for preparing a battery cell according to claim 14, characterized in that, The positive terminal includes: Stamping forms the first basic component; Press the periphery of the first base component and squeeze the central area of ​​the first base component to form a first intermediate component with a first protrusion on one side; The first intermediate component is edge-cut, and the outer portion of the first protrusion is removed along the first preset position to form a positive electrode post including a first main body, a first connecting portion, and a first extension portion.

16. The method for preparing a single battery cell according to claim 14, characterized in that, The negative terminal includes: Stamping forms the second basic component; Press the periphery of the second base component and squeeze the central area of ​​the second base component to form a second intermediate component with a second protrusion on one side; The second intermediate part is edge-cut, and the outer part of the second protrusion is removed along the second preset position to form a negative electrode post including a second main body, a second connecting part and a second extension part.

17. A battery device, characterized in that, Includes the battery cell according to any one of claims 1 to 13, or the battery cell made by the method of preparing the battery cell according to any one of claims 14 to 16.

18. An energy storage device, characterized in that, Includes the battery device of claim 17, the battery device being used for storing electrical energy.

19. An electrical appliance, characterized in that, Includes the battery device of claim 17, the battery device being used to provide electrical energy.

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