Single battery and preparation process

Abstract

The invention discloses a single battery and a preparation process, and belongs to the technical field of batteries. Each single battery comprises a cover plate assembly and an electrode assembly, the electrode assembly is arranged on one side of the cover plate assembly in the thickness direction, and the electrode assembly comprises a tab; the cover plate assembly comprises a cover plate body, a pole, a limiting block and a connecting sheet; an assembly hole is formed in the cover plate body; the pole is arranged in the assembly hole in a penetrating manner; the limiting block is arranged in the assembly hole in a penetrating manner and is electrically connected with the pole; the connecting piece is arranged on the side, facing the electrode assembly, of the cover plate body and comprises a first connecting part, a second connecting part and a bent part, the first connecting part is connected with the limiting block, the second connecting part is connected with the tab, and the width size of the bent part is smaller than the width size of the first connecting part and the width size of the second connecting part in the length direction of the cover plate assembly. The characteristic that the bending part of the connecting sheet is easy to bend is utilized, and the state of the assembled connecting sheet is changed, so that the space occupied by the bending of the connecting sheet and the tab is reduced, the number of procedures is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This application belongs to the technical field of batteries, and particularly relates to a single cell battery and a preparation process thereof. Background Art

[0002] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in the field of electric vehicles.

[0003] However, the pole column and the pole ear in the battery cover plate assembly are usually connected by a connecting piece. The bending of the connecting piece and the pole ear occupies a relatively large amount of space inside the battery, and the bending and assembly processes are complex, with low yield and high cost, resulting in insufficient product competitiveness. Summary of the Invention

[0004] Object of the Invention: The embodiments of this application provide a single cell battery, aiming to overcome the technical problems that the assembly process of the current pole column and pole ear is complex, and the connecting piece and the pole ear occupy a relatively large amount of space inside the battery; another object of the embodiments of this application is to provide a preparation process of a single cell battery.

[0005] Technical Solution: The embodiments of this application provide a single cell battery, including: a cover plate assembly and an electrode assembly. The electrode assembly is disposed on one side in the thickness direction of the cover plate assembly, and the electrode assembly includes a pole ear.

[0006] The cover plate assembly includes:

[0007] A cover plate body, which is provided with an assembly hole along the thickness direction;

[0008] A pole column, which is inserted into the assembly hole;

[0009] A limiting block, which is inserted into the assembly hole and is electrically connected to the pole column;

[0010] A connecting piece, which is disposed on the side of the cover plate body facing the electrode assembly. The connecting piece includes a first connecting portion, a second connecting portion and a bending portion. In a plane perpendicular to the thickness direction, the bending portion is located between the first connecting portion and the second connecting portion and connects the first connecting portion and the second connecting portion respectively. The first connecting portion is connected to the limiting block, the second connecting portion is connected to the pole ear, and along the length direction of the cover plate assembly, the bending portion has a width dimension of a mm, and the first connecting portion and the second connecting portion have a width dimension of b mm, satisfying a < b.

[0011] In some embodiments, the bending portion includes a plurality of bending segments, and the plurality of bending segments are arranged at intervals along the length direction of the cover plate assembly.

[0012] In some embodiments, along the thickness direction, the second connecting portion has a thickness dimension t mm, satisfying 0.2≤t≤1.8.

[0013] In some embodiments, the pole includes a main body and a first protrusion arranged along the thickness direction, the main body is arranged on a side of the pole away from the limit block, and is partially located on a side of the cover body away from the electrode assembly, and the first protrusion is penetrated into the assembly hole;

[0014] The limiting block is provided with a through hole along the thickness direction, and the first protrusion is passed through the through hole and connected to the limiting block to seal the through hole;

[0015] The limit block portion is located on a side of the cover plate body facing the electrode assembly, and the limit block and the pole jointly clamp the two sides of the cover plate body along the thickness direction.

[0016] In some embodiments, the limit block is in a step shape, including a first step, a second step and a third step arranged along the thickness direction, the first step is inserted into the assembly hole, the third step is connected to the side of the cover body facing the electrode assembly, and the second step is respectively connected to the first step and the third step;

[0017] The through hole passes through the first step, the second step and the third step;

[0018] The main body and the third step jointly clamp two sides of the cover body along the thickness direction.

[0019] In some embodiments, the limiting block and the connecting piece are an integrated structure.

[0020] In some embodiments, along the thickness direction, the first step has a thickness dimension T mm, satisfying 1.2≤T≤2.5.

[0021] In some embodiments, the single cell battery also includes a seal, which includes a first sealing segment, a second sealing segment and a third sealing segment, the first sealing segment surrounds the first step and is clamped between the second step and the pole, the third sealing segment surrounds the second step and is clamped between the third step and the cover body, and the second sealing segment passes through the assembly hole and connects the first sealing segment and the third sealing segment respectively.

[0022] In some embodiments, the electrode assembly includes an electrode body. The tab includes a first section and a second section. The first section is connected to one side of the cover plate body facing the cover plate body, and the second section is connected to the electrode body. One end away from the electrode body is bent and then connected to the first section; a gap is provided between the second section and the second connecting portion.

[0023] The embodiment of the present application also discloses a preparation process for a single cell, including:

[0024] Assemble the cover plate assembly, and the second connecting portion extends away from the cover plate body relative to the first connecting portion;

[0025] Connect the second connecting portion to the tab;

[0026] Drive the bent portion to deform, and drive the second connecting portion to rotate in the direction of the cover plate body until the tab is bent, and part of the tab extends along the thickness direction of the cover plate body, and part of the tab is connected to one side of the second connecting portion facing the cover plate body.

[0027] Beneficial effects: In the single cell of the embodiment of the present application, by setting the width dimension of the bent portion to be smaller than the width dimensions of the first connecting portion and the second connecting portion, the connecting piece is easily bent at the position of the bent portion; during the assembly process, by bending the connecting piece, the tab and the second connecting portion of the connecting piece are in a position more conducive to welding, facilitating the welding operation and ensuring the welding quality and efficiency. After the welding is completed, by utilizing the easy-bending characteristic of the bent portion again, an external force is applied to the second connecting portion to drive the tab to bend. At the same time, the connecting piece is restored to the unbent state, and both the first connecting portion and the second connecting portion are on the same horizontal plane perpendicular to the thickness direction, reducing the space occupied by the bending of the connecting piece and the tab, and cleverly combining the originally required separate tab bending process and the connecting piece assembly process, reducing the number of processes and improving the production efficiency. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0029] Figure 1 It is a three-dimensional structural schematic diagram of the single cell of the embodiment of the present application;

[0030] Figure 2 It is a top view structural schematic diagram of the single cell of the embodiment of the present application;

[0031] Figure 3 is Figure 2 a schematic cross-sectional structure diagram in the A-A direction in

[0032] Figure 4 is Figure 3 a partially enlarged schematic diagram at position B in

[0033] Figure 5 a schematic assembly structure diagram of the cover plate body, the limiting block and the connecting piece in the embodiment of the present application;

[0034] Figure 6 a schematic connection structure diagram of the connecting piece and the limiting block in the embodiment of the present application;

[0035] Figure 7 a half-sectional schematic diagram of the integral structure of the connecting piece and the limiting block in the embodiment of the present application;

[0036] Figure 8 a schematic structure diagram of the connection between the tab and the connecting piece during the assembly of the single cell in the embodiment of the present application;

[0037] Figure 9 is Figure 8 a schematic cross-sectional structure diagram in the C-C direction in

[0038] Figure 10 is Figure 9 a partially enlarged schematic diagram at position D in

[0039] Figure 11 a schematic assembly relationship diagram of the connecting piece, the limiting block and the cover plate body in the single cell of the embodiment of the present application, in which the connecting piece is in a bent form in the figure;

[0040] Figure 12 a three-dimensional structure diagram of the connection between the connecting piece and the limiting block in the single cell of the embodiment of the present application;

[0041] Reference numerals: 1. Cover plate assembly; 2. Electrode assembly; X. Thickness direction; 21. Tab; 11. Cover plate body; 110. Assembly hole; 12. Terminal; 13. Limiting block; 14. Connecting piece; 141. First connecting portion; 142. Second connecting portion; 143. Bent portion; Y. Length direction; 1431. Bent section; 121. Main body portion; 122. First convex portion; 130. Through hole; 131. First step; 132. Second step; 133. Third step; 15. Sealing member; 151. First sealing section; 152. Second sealing section; 153. Third sealing section; 22. Electrode main body; 211. First section; 212. Second section. Detailed implementation manners

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present application.

[0043] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application. In the description of the present application, "a plurality of" means two or more, and "at least one" may mean one, two or more, unless otherwise specifically defined. The terms "first", "second", "third", etc. are only used for naming the components or embodiments with numbers for the convenience of description, and do not imply an important order among the components or embodiments.

[0044] It should also be noted that in the accompanying drawings of the specification of the present application, the arrow marked with X indicates the thickness direction, and the arrow marked with Y indicates the length direction. In the description of the present application, the introduction of the thickness direction and the length direction is to more clearly define the structure and relative positional relationship of the components in the single cell.

[0045] As the preamble of the embodiments of the present application, with the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in the field of electric vehicles. However, the pole column and the pole ear in the battery cover assembly are usually connected by a connecting piece, and the bending of the connecting piece and the pole ear will occupy more space inside the battery, and the bending and assembly processes are complex, with a low yield and high cost, resulting in insufficient product competitiveness. At the same time, the pole ear and the pole column usually need to be connected by a connecting piece, resulting in an increase in the number of components and a complex assembly process. Moreover, the existing pole column cannot be formed in one processing, and the processing cost is relatively high.

[0046] In view of this, the embodiments of the present application provide a single cell, aiming to solve at least one of the above technical problems.

[0047] Please refer to Figures 1 to 12As shown in the figure, the single cell in the embodiment of the present application includes: a cover plate assembly 1 and an electrode assembly 2. The electrode assembly 2 is disposed on one side of the cover plate assembly 1 in the thickness direction X. The electrode assembly 2 includes a tab 21. The cover plate assembly 1 includes a cover plate body 11, a pole column 12, a limiting block 13, and a connecting piece 14. The cover plate body 11 is provided with an assembly hole 110 in the thickness direction X. The pole column 12 is inserted into the assembly hole 110. The limiting block 13 is inserted into the assembly hole 110 and is electrically connected to the pole column 12. The connecting piece 14 is disposed on the side of the cover plate body 11 facing the electrode assembly 2. The connecting piece 14 includes a first connecting portion 141, a second connecting portion 142, and a bending portion 143. In a plane perpendicular to the thickness direction X, the bending portion 143 is located between the first connecting portion 141 and the second connecting portion 142 and connects the first connecting portion 141 and the second connecting portion 142 respectively. The first connecting portion 141 is connected to the limiting block 13, and the second connecting portion 142 is connected to the tab 21. And along the length direction Y of the cover plate assembly 1, the bending portion 143 has a width dimension of a mm, and the first connecting portion 141 and the second connecting portion 142 have a width dimension of b mm, satisfying a < b (such as Figure 5 and Figure 6 shown).

[0048] It should be understood that by setting the width dimension of the bending portion 143 to be smaller than the width dimensions of the first connecting portion 141 and the second connecting portion 142, the connecting piece 14 is likely to be bent at the position of the bending portion 143. During the assembly process, by bending the connecting piece 14, the tab 21 and the second connecting portion 142 are in a position more conducive to welding, facilitating the operation of the welding tool and ensuring the welding quality and efficiency. After the welding is completed, by utilizing the easy-bending characteristic of the bending portion 143 again, by applying an external force to the second connecting portion 142, the tab 21 is driven to bend. At the same time, the connecting piece 14 is restored to the unbent state, reducing the space occupied by the bending of the connecting piece 14 and the tab 21. The bending process of the tab 21 and the assembly process of the connecting piece 14, which originally needed to be carried out separately, are skillfully combined, reducing the number of processes and improving the production efficiency. The traditional bending methods of the connecting piece 14 and the tab 21 often require a large space to complete the bending action and accommodate the bent components. In the present application, by driving the tab 21 to bend through the bending portion 143, the bending path and position of the tab 21 can be more accurately controlled, reducing unnecessary space occupation, helping to improve the overall space utilization rate of the single cell, and thus enhancing the energy density of the battery.

[0049] Please refer to Figure 5 and Figure 6As shown, in some embodiments, the bending portion 143 includes a plurality of bending segments 1431, and the plurality of bending segments 1431 are arranged at intervals along the length direction Y of the cover plate assembly 1. It should be understood that the plurality of bending segments 1431 are arranged at intervals along the length direction Y of the cover plate assembly 1, so that the stress during bending of the connecting member is dispersed in each bending segment 1431, avoiding stress concentration at a certain place and causing structural damage, effectively enhancing the stability of the entire connection structure during long-term use. Especially when the battery undergoes working conditions such as repeated charging and discharging and temperature changes, it can better maintain the electrical connection between the tab 21 and the terminal 12, ensuring the reliability of the battery performance.

[0050] Please refer to Figure 4 As shown, in some embodiments, along the thickness direction X, the second connecting portion 142 has a thickness dimension t mm, satisfying 0.2 ≤ t ≤ 1.8. It should be understood that by setting the thickness dimension of the second connecting portion 142 within the range of 0.2 mm to 1.8 mm, it is ensured that the second connecting portion 142 has good electrical conductivity, thereby effectively conducting current and ensuring that the battery can work stably at different charge and discharge rates. At the same time, the appropriate thickness can ensure that the second connecting portion 142 has sufficient mechanical strength to support the tab 21 and can withstand various external forces, preventing the second connecting portion 142 from breaking under the action of external forces, resulting in the separation of the tab 21 from the connecting piece 14 and thus causing the battery to fail.

[0051] Specifically, t can be any value among 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm or a range value between two values. Within the above range, when t is larger, the structural strength of the second connecting portion 142 is higher, and the connection reliability between the second connecting portion 142 and the tab 21 is higher. When t is smaller, the space occupied by the connecting piece 14 inside the battery is smaller, improving the space utilization rate. Moreover, the thinner the second connecting portion 142, the higher the welding efficiency with the tab 21, and it is also beneficial to realize the miniaturization and light weight of the battery.

[0052] In some embodiments, a second connecting portion 142 with a gradually changing thickness (not shown in the figure) is adopted. From the end connected to the tab 21 to the end connected to the bending portion 143, the thickness gradually decreases from 1 mm to 0.5 mm. The thicker part connected to the tab 21 can ensure the electrical performance and mechanical strength during high-current discharge, while the thinner part near the bending portion 143 can better adapt to the bending action of the bending portion 143 on the premise of ensuring a certain strength, reducing stress concentration and improving the reliability of the entire connecting member.

[0053] Please refer to Figure 4 WithFigure 10 As shown, in some embodiments, the terminal post 12 includes a main body portion 121 and a first convex portion 122 arranged along the thickness direction X. The main body portion 121 is disposed on the side of the terminal post 12 away from the limiting block 13 and partially located on the side of the cover plate body 11 facing away from the electrode assembly 2. The first convex portion 122 passes through the assembly hole 110. The limiting block 13 is provided with a through hole 130 along the thickness direction X. The first convex portion 122 passes through the through hole 130 and is connected to the limiting block 13 to seal the through hole 130. A part of the limiting block 13 is located on the side of the cover plate body 11 facing the electrode assembly 2. The limiting block 13 and the terminal post 12 jointly clamp both sides of the cover plate body 11 along the thickness direction X. It should be understood that by arranging the first convex portion 122 to pass through the through hole 130 and be connected to the limiting block 13, not only the sealing between the terminal post 12 and the limiting block 13 is achieved, but also a reliable electrical connection is established between the terminal post 12 and the limiting block 13. This connection method reduces the resistance of the electrical connection, ensures that the current can smoothly flow from the terminal post 12 to the limiting block 13, and then is transmitted to the tab 21 through the connecting piece 14, improving the charge and discharge efficiency of the battery.

[0054] At the same time, the stable electrical connection also helps to improve the consistency of the battery and extend the service life of the battery. Furthermore, the limiting block 13 and the terminal post 12 jointly clamp both sides of the cover plate body 11 along the thickness direction X, making full use of the space of the cover plate assembly 1, making the structure of the single cell more compact, the connection between the components of the cover plate assembly 1 closer, forming a stable overall structure, and being able to better maintain the relative positions of the components in the case of external force impact, vibration, etc. of the battery, preventing the components from loosening or falling off. It is also beneficial to the miniaturization design of the battery and improves the energy density of the battery.

[0055] The cover plate assembly 1 of the present application has high mechanical strength. The large surface of the main body portion 121 faces the cover plate body 11 for support, and the large surface of the limiting block 13 faces the cover plate body 11 for support. When the battery is subjected to external forces, it can better disperse the stress, prevent the cover plate body 11 from deforming or being damaged, thereby improving the mechanical stability and service life of the single cell.

[0056] It should also be understood that when assembling the cover plate assembly 1 of the present application, only need to insert the limiting block 13 into the assembly hole 110, and then insert the first convex portion 122 of the terminal post 12 into the through hole 130 of the limiting block 13 and perform fixed connection (such as welding, etc.), then the assembly among the terminal post 12, the limiting block 13 and the cover plate body 11 can be completed, improving the production efficiency and reducing the assembly cost.

[0057] In some embodiments, the main body portion 121 and the first convex portion 122 of the terminal post 12 are of an integral structure.

[0058] In some embodiments, the connection method between the first convex portion 122 passing through the through hole 130 and the limiting block 13 can be welding connection. At the same time, the first convex portion 122 and the limiting block 13 can also be riveted. Specifically, a rivet structure is provided at the end of the first convex portion 122 of the terminal post 12. After the first convex portion 122 passes through the through hole 130, the rivet structure at the end of the first convex portion 122 is deformed by a riveting tool so that it is tightly connected to the limiting block 13. This riveting method has the advantages of fast connection speed, high connection strength and not being prone to false soldering, etc.

[0059] Specifically, after the first convex portion 122 of the terminal post 12 passes through the through hole 130, a riveting hole (not shown in the figure) can be formed by extrusion at the end of the first convex portion 122, so that the end of the first convex portion 122 and the limiting block 13 form an interference fit, initially realizing the positioning and assembly of the first convex portion 122 and the limiting block 13, strengthening the positioning stability and enhancing the connection. At the same time, to a certain extent, the connection sealing performance is improved. The frictional force generated by the interference fit can effectively prevent the relative displacement between the terminal post 12 and the limiting block 13 due to factors such as vibration and temperature change during the operation of the battery, ensuring that the terminal post 12 and the limiting block 13 always maintain an accurate relative position, thereby ensuring the stability of the overall structure of the battery and the reliability of the electrical connection. Realizing the preliminary positioning and assembly by extruding to form a riveting hole simplifies the entire assembly process. Without additional complex positioning tooling or cumbersome adjustment steps, the operator only needs to perform a simple extrusion operation after the first convex portion 122 passes through, and can quickly achieve preliminary positioning, greatly improving the assembly efficiency, reducing the labor cost, and also being beneficial to large-scale automated production.

[0060] Specifically, the shapes of the first convex portion 122 and the through hole 130 can be optimized according to actual needs. For example, the first convex portion 122 is designed as a polygon (such as a hexagon), and the through hole 130 is also a hexagon correspondingly, which can increase the frictional force between the two and prevent relative rotation during use. Or the first convex portion 122 is designed in a shape with grooves, and protrusions matching the grooves are provided in the through hole 130. Through this concave-convex matching method, the stability and reliability of the connection are further enhanced. Or, the first convex portion 122 can be designed as a cone, which can better fit with the limiting block 13 when passing through the through hole 130, increasing the tightness of the connection. In addition, anti-slip textures can be provided on the outer surface of the terminal post 12 to facilitate the operation of installing and disassembling the terminal post 12.

[0061] Please refer to Figure 4 、 Figure 7 、 Figure 10 and Figure 12As shown, in some embodiments, the limiting block 13 is stepped, including a first step 131, a second step 132, and a third step 133 arranged along the thickness direction X. The first step 131 is inserted into the assembly hole 110, the third step 133 is connected to the side of the cover plate body 11 facing the electrode assembly 2, and the second step 132 connects the first step 131 and the third step 133 respectively; the through hole 130 penetrates through the first step 131, the second step 132, and the third step 133; the main body portion 121 and the third step 133 jointly clamp both sides of the cover plate body 11 along the thickness direction X. It should be understood that by designing the limiting block 13 with a multi-step structure, the contact area between the limiting block 13 and the cover plate body 11 is significantly increased. The first step 131 is inserted into the assembly hole 110 and forms a positioning fit with the first convex portion 122 of the pole column 12, which can accurately position the installation position of the limiting block 13 and prevent it from shaking or shifting in the assembly hole 110; the second step 132 surrounds and connects the first step 131 and the third step 133, increasing the overall structural strength of the limiting block 13; the third step 133 surrounds the assembly hole 110 and is located on the side of the cover plate body 11 facing the electrode assembly 2, further increasing the contact area with the cover plate body 11, making the connection between the limiting block 13 and the cover plate body 11 more stable. The first convex portion 122 of the pole column 12 penetrates through the through hole 130 opened on the limiting block 13, which can better achieve a tight connection with the limiting block 13, thus ensuring the stability of the entire electrical connection system. At the same time, the design of the limiting block 13 with a multi-step structure can more effectively disperse various stresses suffered by the battery during use. When the battery is subjected to external mechanical forces, different steps can respectively bear and transfer the stresses, avoiding stress concentration at a certain part, thereby reducing the possibility of damage to the cover plate body 11 or the limiting block 13 due to stress concentration.

[0062] It should also be understood that the through-hole 130 penetrates through the first step 131, the second step 132, and the third step 133 along the thickness direction X. On the one hand, it can provide a heat dissipation channel, enabling the heat generated inside the battery to be conducted to the outside through these channels, thereby improving the heat dissipation performance of the battery. On the other hand, during the assembly process of the terminal post 12 and the limiting block 13, the through-hole 130 can provide an observation channel, facilitating the operator to view in real time the position and state of the insertion of the first convex portion 122 of the terminal post 12, ensuring the accuracy of the assembly. Moreover, the fixed connection between the first convex portion 122 of the terminal post 12 and the limiting block 13 needs to be realized through the through-hole 130. When using the welding method, the operator can directly weld the connection part between the first convex portion 122 and the limiting block 13 through the through-hole 130, ensuring that the welding position is accurate and error-free, ensuring the sealing performance of the connection position between the terminal post 12 and the limiting block 13, avoiding problems such as false soldering and leakage welding, and thus ensuring that the current can be stably and efficiently conducted between the terminal post 12 and the limiting block 13, reducing the contact resistance, and improving the overall performance of the battery. When using the riveting process, the through-hole 130 provides an operating space for the riveting tool, enabling the rivet to smoothly pass through the first convex portion 122 and the limiting block 13, and after riveting deformation, firmly fixing the two together. In addition, the through-hole 130 also facilitates subsequent quality inspection. The inspection personnel can use professional tools to perform flaw detection and sealing detection on the connection part between the terminal post 12 and the limiting block 13 through the through-hole 130, ensuring that the connection quality meets the standards and guaranteeing the reliability and safety of the single-cell battery.

[0063] Please refer to Figure 9 and Figure 10 As shown, in some embodiments, the limiting block 13 and the connecting piece 14 are of an integral structure. It should be understood that by combining the limiting block 13 and the connecting piece 14 into one, the internal structure of the battery is greatly simplified, the number of components is reduced, not only the cost is reduced, but also the assembly process is simplified, and the production efficiency is improved. During the assembly process, there is no need to perform multiple connection operations between the connecting piece 14, the limiting block 13, and the tab 21, reducing the probability of assembly errors and further reducing the production cost. The limiting block 13 and the connecting piece 14 being of an integral structure reduces the length of the tab 21, reduces the resistance, and during the charging and discharging process of the battery, it can reduce energy loss, improve the charging and discharging efficiency and energy density of the battery. At the same time, the reduction in the length of the tab 21 eliminates the risk of tearing when the battery is subjected to external forces such as vibration and extrusion, improving the stability and reliability of the battery product and extending the service life of the battery.

[0064] Please refer to Figure 4As shown, in some embodiments, along the thickness direction X, the first step 131 has a thickness dimension of T mm, satisfying 1.2 ≤ T ≤ 2.5. It should be understood that by setting the thickness dimension of the first step 131 between 1.2 mm and 2.5 mm, sufficient mechanical strength of the limiting block 13 can be ensured, avoiding deformation or even damage of the limiting block 13 under external forces during the production, transportation, and use of the battery, and ensuring the stability of the battery structure. Specifically, T can be any value among 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm or a range value between two values. Within the above range, when T is closer to 1.2 mm, the weight of the limiting block 13 is lighter, and the connection strength between the limiting block 13 and the pole 12 decreases, affecting the connection stability; when T is closer to 2.5 mm, the thickness dimension of the limiting block 13 increases, the structural strength is better, but the stability of the stepped structure of the limiting block 13 slightly decreases, and at the same time, it is not conducive to the lightweight design of the battery.

[0065] In some embodiments, the single cell further includes a seal 15, which includes a first sealing section 151, a second sealing section 152, and a third sealing section 153. The first sealing section 151 surrounds the first step 131 and is clamped between the second step 132 and the pole 12. The third sealing section 153 surrounds the second step 132 and is clamped between the third step 133 and the cover body 11. The second sealing section 152 passes through the assembly hole 110 and connects the first sealing section 151 and the third sealing section 153 respectively. It should be understood that the three-section sealing structure design can seal the assembly hole 110 and its surrounding area in all directions. The first sealing section 151 is clamped between the pole 12 and the second step 132, which can effectively prevent liquid or gas from infiltrating into the battery interior from the connection part between the pole 12 and the limiting block 13. The third sealing section 153 is clamped between the third step 133 and the cover body 11, which can prevent external impurities, moisture, etc. from entering through the contact surface between the limiting block 13 and the cover body 11. The second sealing section 152 passes through the assembly hole 110 and connects the first sealing section 151 and the third sealing section 153, forming a continuous sealing path, greatly improving the integrity and reliability of the seal, ensuring the stability of the battery internal environment, preventing the leakage of the electrolyte inside the battery and the intrusion of external substances, thereby extending the service life of the battery and ensuring its stable performance. The seal 15 not only plays a sealing role, but also can enhance the mechanical performance of the battery structure to a certain extent. When the battery is subjected to external vibration or impact, the seal 15 can act as a buffer medium, absorbing part of the impact force, reducing the relative displacement and friction between the pole 12, the connecting piece 14, and the cover body 11, and reducing the risk of component damage. The seal 15 is usually made of insulating material, which can improve the electrical insulation performance inside the battery while realizing the sealing function. Especially at the connection parts between the pole 12 and the limiting block 13, and between the limiting block 13 and the cover body 11, the seal 15 can effectively isolate components with different potentials, prevent the occurrence of electrical short-circuit phenomena, and ensure the electrical safety of the battery.

[0066] It should also be understood that the three-section seal 15 and the multi-step limiting block 13 are relatively convenient to assemble, improving the assembly efficiency and reducing the assembly error.

[0067] Please refer to Figure 4As shown, in some embodiments, the electrode assembly 2 includes an electrode body 22. The tab 21 includes a first section 211 and a second section 212. The first section 211 is connected to the side of the second connecting portion 142 facing the cover plate body 11. The second section 212 is connected to the electrode body 22, and the end far from the electrode body 22 is bent and then connected to the first section 211. There is a spaced arrangement between the second section 212 and the second connecting portion 142. It should be understood that during the assembly process of the single cell, the tab 21 is only bent once, forming the first section 211 connected to the connecting piece 14 and the second section 212 connected to the electrode body 22. The tab 21 requires fewer bending times, reducing the occupation of the internal space of the battery. The bending process is simple, the assembly is convenient, and the required length of the tab 21 can be reduced, eliminating the tearing risk caused by multiple bends of the tab 21 and improving the battery performance. At the same time, the structure of the two-section tab 21 optimizes the current transmission path between the electrode assembly 2 and the cover plate assembly 1, reducing the resistance consumption and improving the charge and discharge efficiency of the battery. The first section 211 of the tab 21 is connected to the side of the second connecting portion 142 facing the cover plate body 11. When the second connecting portion 142 flips towards the cover plate body 11, it drives the tab 21 to bend. On the one hand, the second connecting portion 142 plays a role in connecting and supporting the first section 211, increasing the connection stability and reducing the risk of connection failure caused by vibration or deformation during use. On the other hand, the assembly process can be simplified and the bending efficiency of the tab 21 can be improved. By having a spaced arrangement between the second section 212 and the second connecting portion 142, it helps to reduce the risk of the bending area of the tab 21 being squeezed and damaged by the second connecting portion 142 during the bending process, causing a short circuit, and improving the safety of the battery.

[0068] Please refer to Figures 8 to 12As shown in the figure, the embodiment of the present application further provides a preparation process for a single cell, including: assembling a cover plate assembly 1, with the second connecting portion 142 extending away from the cover plate body 11 relative to the first connecting portion 141; connecting the second connecting portion 142 to the tab 21; driving the bending portion 143 to deform, and driving the second connecting portion 142 to rotate towards the direction where the cover plate body 11 is located until the tab 21 is bent, and a part of the tab 21 extends along the thickness direction X of the cover plate body 11, and a part of the tab 21 is connected to the side of the second connecting portion 142 facing the cover plate body 11. It should be understood that for the above preparation process of the single cell, by first assembling the cover plate assembly 1, then connecting the second connecting portion 142 to the tab 21, and finally driving the bending portion 143 to deform to achieve the bending of the tab 21, the precise positioning and connection of each component can be ensured, and the assembly error can be reduced. The method of driving the bending portion 143 to deform and driving the second connecting portion 142 to rotate realizes the automatic bending and precise positioning of the tab 21, reduces the difficulty and labor intensity of manual operation. It makes the connection of the tab 21 more firm and reliable, effectively reducing the performance degradation and safety hazards caused by poor connection of the tab 21 during the use of the battery. The simplified assembly process makes it easier for operators to get started, reduces the assembly difficulty, reduces the assembly mistakes caused by improper operation, improves the yield rate of the product, and is also conducive to realizing automated assembly, further improving the production efficiency and the stability of product quality.

[0069] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0070] The above has introduced in detail a single cell and its preparation process provided by the embodiments of the present application, and specific examples have been used to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A single cell battery, characterized in that: include: A cover plate assembly and an electrode assembly, wherein the electrode assembly is arranged on one side of the cover plate assembly in a thickness direction, and the electrode assembly includes an electrode tab; The cover plate assembly comprises: The cover body is provided with an assembly hole along the thickness direction; A pole, inserted into the assembly hole; A limit block is inserted into the assembly hole and connected to the pole; A connecting piece is arranged on the side of the cover plate body facing the electrode assembly, and the connecting piece includes a first connecting portion, a second connecting portion and a bending portion. On a plane perpendicular to the thickness direction, the bending portion is located between the first connecting portion and the second connecting portion and respectively connects the first connecting portion and the second connecting portion, the first connecting portion is connected to the limit block, the second connecting portion is connected to the pole ear, and along the length direction of the cover plate assembly, the bending portion has a width dimension a mm, and the first connecting portion and the second connecting portion have a width dimension b mm, satisfying a<b.

2. The single cell according to claim 1, characterized in that: The bending portion includes a plurality of bending segments, and the plurality of bending segments are arranged at intervals along the length direction of the cover plate assembly.

3. The single cell according to claim 1, characterized in that: Along the thickness direction, the second connection portion has a thickness dimension t mm, satisfying 0.2≤t≤1.

8.

4. The single cell according to claim 1, characterized in that: The pole comprises a main body and a first convex portion arranged in a thickness direction, the main body is arranged on a side of the pole away from the limit block, and is partially located on a side of the cover body away from the electrode assembly, and the first convex portion is penetrated in the assembly hole; The limiting block is provided with a through hole along the thickness direction, and the first protrusion is passed through the through hole and connected to the limiting block to seal the through hole; The limit block portion is located on a side of the cover plate body facing the electrode assembly, and the limit block and the pole jointly clamp the two sides of the cover plate body along the thickness direction.

5. The single cell according to claim 4, characterized in that: The limit block is in a step shape, and includes a first step, a second step and a third step arranged along the thickness direction, the first step is inserted into the assembly hole, the third step is connected to the side of the cover plate body facing the electrode assembly, and the second step is respectively connected to the first step and the third step; The through hole passes through the first step, the second step and the third step; The main body and the third step jointly clamp two sides of the cover body along the thickness direction.

6. The single cell according to any one of claims 1 to 5, characterized in that: The limiting block and the connecting piece are an integrated structure.

7. The single cell according to claim 5, characterized in that: Along the thickness direction, the first step has a thickness dimension T mm, satisfying 1.2≤T≤2.

5.

8. The single cell according to claim 5, characterized in that: The single cell battery also includes a seal, which includes a first sealing section, a second sealing section and a third sealing section. The first sealing section surrounds the first step and is clamped between the second step and the pole, the third sealing section surrounds the second step and is clamped between the third step and the cover body, and the second sealing section passes through the assembly hole and connects the first sealing section and the third sealing section respectively.

9. The single cell according to claim 1, characterized in that: The electrode assembly includes an electrode body, and the electrode ear includes a first section and a second section, the first section is connected to the second connecting portion on one side facing the cover plate body (11), the second section is connected to the electrode body, and one end away from the electrode body is bent and connected to the first section; the second section and the second connecting portion are spaced apart.

10. A process for preparing a single cell, characterized in that: include: Assembling the cover plate assembly, the second connecting portion extends relative to the first connecting portion toward a side away from the cover plate body; connecting the second connecting portion and the tab; The driving bending portion is deformed and drives the second connecting portion to rotate toward the direction of the cover body until the pole ear is bent and part of the pole ear extends along the thickness direction of the cover body and part of the pole ear is connected to the side of the second connecting portion facing the cover body.

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