Assembly structure of pole group and cover plate and battery cell

Abstract

The invention relates to the technical field of batteries, and particularly discloses an assembly structure of a pole group and a cover plate and a battery cell, the assembly structure of the pole group and the cover plate comprises the battery cell cover plate and the pole group, a first plastic part of the battery cell cover plate is arranged on one side of a cover plate body along a first direction, and the first plastic part is arranged towards the pole group. Supporting parts are arranged at the two ends of the first plastic part in the second direction. Two first convex parts are arranged on one side, facing the battery cell cover plate, of the pole group, each first convex part extends along the first direction and is partially accommodated in the first accommodating space of the corresponding supporting part, and the first bottom wall of the supporting part is propped against the end surface, facing the battery cell cover plate, of the first convex part. Therefore, good positioning between the first plastic part and the pole group is realized, the assembly precision is high, the direction and the position of the pole group entering the shell are not easy to deviate, and meanwhile, the volume of the pole group is increased, so that the capacity of the battery cell is improved. The invention also provides a battery cell which comprises the assembling structure of the pole group and the cover plate.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an assembly structure of electrode assembly and cover plate, and a battery cell. Background Technology

[0002] The cover plates are all flat, and the rivet blocks protrude from the aluminum plate. During module assembly, this occupies external space, affecting the assembly rate of the PCAK. Furthermore, the rivet blocks and the protruding plastic on the cover plate (as shown in the diagram) provide poor protection, often resulting in bumps and scratches during transportation and assembly, leading to performance, safety, and appearance defects in the cells and batteries. The corresponding electrode group space utilization is low, which is detrimental to increasing the cell capacity.

[0003] Currently, the end face of the electrode assembly facing the cell cover in a battery cell is generally a planar structure. This means the space between the electrode assembly and the cell cover cannot be effectively utilized, negatively impacting cell capacity and assembly ratio. Furthermore, the side of the cell cover facing the electrode assembly has a lower plastic component to support it. If the electrode assembly does not properly match the shape of this lower plastic component, the positioning accuracy of the electrode assembly will be insufficient, leading to movement, deformation or tearing of the electrode tabs. Moreover, the lower plastic component lacks a support position in the middle of the electrode assembly, resulting in an imbalance between the support surfaces of the electrode assembly and the cell cover on the lower plastic component. This imbalance can easily cause damage to the electrode sheets and excessive movement when pushing the electrode assembly into the casing and fixing it in place. Summary of the Invention

[0004] The purpose of this invention is to provide an assembly structure for the electrode assembly and cover plate, as well as a battery cell, which can make reasonable use of the space between the electrode assembly and the battery cell cover plate, increase the volume of the electrode assembly, and help improve the battery cell capacity and assembly ratio. At the same time, a support position is provided in the middle of the electrode assembly, so that the pressure on the electrode assembly is more balanced when it is inserted into the shell and after it is fixed in the shell, and it is less likely to cause electrode damage or excessive movement.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides an assembly structure for an electrode assembly and a cover plate, comprising:

[0007] A battery cell cover plate, the battery cell cover plate including a cover plate body and a first plastic part, the first plastic part being disposed on one side of the cover plate body along a first direction, and the first plastic part having support portions at both ends along a second direction, the support portions being hollow to form a first accommodating space;

[0008] The electrode assembly has two first protrusions on one side facing the cell cover plate. Each first protrusion extends along a first direction and is partially accommodated in the first accommodating space of a support portion. The support portion includes a first bottom wall that abuts against the end face of the first protrusion facing the cell cover plate.

[0009] Optionally, the cell cover includes a first electrode post and an insulating protective cover. The post portion of the first electrode post passes through the first plastic part and the cover body in sequence. The plate portion of the first electrode post is located on the side of the first plastic part away from the cover body. The insulating protective cover is adhered to the end face of the plate portion facing the electrode group and abuts against the end of the electrode group facing the cell cover.

[0010] Optionally, the electrode group is further provided with a second protrusion at one end facing the cell cover plate. The second protrusion is located at the middle position of the electrode group along the second direction. The interior of the insulating protective cover is hollow to form a second accommodating space. The second protrusion extends along the first direction and is partially accommodated in the second accommodating space. The insulating protective cover includes a second bottom wall, which abuts against the end face of the second protrusion facing the cell cover plate.

[0011] In this context, along two directions, the width of the first protrusion facing one end of the battery cell cover is W1, and the width of the second protrusion facing one end of the battery cell cover is W2.

[0012] The relationship between W1 and W2 satisfies: 22mm≤2W1+W2≤138mm;

[0013] The value range of W1 is: 8.5mm≤W1≤54mm;

[0014] The value range of W2 is: 5mm≤W2≤30mm.

[0015] Optionally, the first protrusion is provided with a first step in the circumferential direction, the support part includes a first side wall adjacent to the first bottom wall, the inner wall surface of the first side wall is in clearance fit with the first step surface of the first step, the end face of the first side wall facing the pole group is a first support surface, and the first support surface is in clearance fit with the second step surface of the first step.

[0016] And / or, the second protrusion is provided with a second step in the circumferential direction, the insulating protective cover includes a second side wall adjacent to the second bottom wall, the inner wall surface of the second side wall is in clearance fit with the third step surface of the second step, the end face of the second side wall facing the pole group is a second support surface, and the second support surface is in clearance fit with the fourth step surface of the second step.

[0017] Optionally, the distance between two first step surfaces that are opposite each other in the third direction in the first protrusion is L1, and the thickness of the pole group in the third direction is L2;

[0018] The relationship between L1 and L2 satisfies: 1.25mm≤(L2-L1) / 2≤3mm;

[0019] The value range of L1 is: 12mm≤L1≤16mm;

[0020] The value range of L2 is: 16mm≤L2≤20mm.

[0021] Optionally, the electrode group has two tabs at one end facing the cell cover plate, the two tabs are arranged opposite each other on both sides of the second protrusion along the second direction, and both tabs are eccentrically arranged along the third direction;

[0022] Wherein, along the third direction, the distance between the end face of the electrode tab near the center of the electrode group in the thickness direction and the end face of the electrode group away from the electrode tab is L3;

[0023] The relationship between L2 and L3 satisfies: 0.58 ≤ L3 / L2 ≤ 0.75;

[0024] The value range of L3 is: 10mm≤L3≤14mm.

[0025] Optionally, the cell cover includes two conductive connecting pieces, which are respectively disposed on both sides of the insulating protective cover, and the two ends of each conductive connecting piece are electrically connected to the plate body and an electrode tab, respectively.

[0026] Optionally, the conductive connecting piece includes a first connecting plate and a second connecting plate, the first connecting plate and the second connecting plate are perpendicular to each other, the first connecting plate is connected to the plate body, and the second connecting plate is connected to the electrode tab.

[0027] Optionally, the cell cover includes a second plastic part and a connecting block. The second plastic part is disposed on the side of the cover body opposite to the first plastic part, and the connecting block is disposed on the side of the second plastic part away from the cover body. The column portion passes through the first plastic part, the cover body, the second plastic part and the connecting block in sequence and is riveted to the connecting block. The cover body has a groove on the side facing the second plastic part, and the second plastic part and the connecting block are recessed in the groove.

[0028] On the other hand, the present invention provides a battery cell including an electrode assembly, a battery cell cover plate and a housing, wherein the electrode assembly is disposed within the housing, and the battery cell cover plate is encapsulated at the opening of the housing, and the electrode assembly and the battery cell cover plate are connected by an assembly structure of electrode assembly and cover plate as described in any of the above-mentioned schemes.

[0029] The beneficial effects of this invention are as follows:

[0030] This invention provides an assembly structure for an electrode assembly and a cover plate, including a cell cover plate and an electrode assembly. A first plastic part of the cell cover plate is disposed on one side of the cover plate body along a first direction, and the first plastic part faces the electrode assembly. Support portions are provided at both ends of the first plastic part along a second direction, and the interior of each support portion is hollow, forming a first accommodating space. Two first protrusions are provided on the side of the electrode assembly facing the cell cover plate. Each first protrusion extends along the first direction and is partially accommodated within the first accommodating space of a corresponding support portion. The first bottom wall of the support portion abuts against the end face of the first protrusion facing the cell cover plate. This achieves good positioning between the first plastic part and the electrode assembly, resulting in high assembly accuracy. The insertion direction and position of the electrode assembly are less prone to shifting, and the increased volume of the electrode assembly helps to improve the cell capacity.

[0031] This invention also provides a battery cell, including an electrode assembly, a cell cover, and a housing. The electrode assembly is disposed within the housing, and the cell cover is encapsulated at the opening of the housing. The electrode assembly and the cell cover are connected using the aforementioned electrode assembly and cover assembly structure. By employing this electrode assembly and cover assembly structure, the internal space utilization of the battery cell can be improved. The increased volume of the electrode assembly facilitates increased battery capacity. Furthermore, the electrode assembly is adapted to the cell cover, which provides excellent protection for the integrated connecting block, second plastic component, and first terminal post, preventing damage during transportation, assembly, and other manufacturing processes. This ensures good safety performance of the battery cell. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the pole group provided in an embodiment of the present invention;

[0034] Figure 2 This is a top view of the pole group provided in an embodiment of the present invention;

[0035] Figure 3 for Figure 2 Cross-sectional view of section I-I;

[0036] Figure 4 This is a right view of the pole group provided in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the structure of the battery cell cover plate provided in an embodiment of the present invention;

[0038] Figure 6This is a schematic diagram of the battery cell cover plate provided in an embodiment of the present invention from another perspective;

[0039] Figure 7 This is a schematic diagram of the battery cell structure provided in an embodiment of the present invention;

[0040] Figure 8 This is a cross-sectional view of the battery cell provided in an embodiment of the present invention;

[0041] Figure 9 for Figure 8 Enlarged view of a section at point II;

[0042] Figure 10 yes Figure 8 A magnified view of section III in the middle.

[0043] In the picture:

[0044] 100. Cell cover plate; 110. Cover plate body; 111. First panel; 112. Transition plate; 113. Second panel; 1131. Groove; 1132. Reinforcing rib; 120. Second plastic part; 121. Receiving groove; 130. Connecting block; 140. First plastic part; 141. Plastic part body; 1411. Limiting groove; 142. Support part; 1421. First receiving space; 1422. First bottom wall; 1423. First side wall; 1424. First support surface; 150. First pole post; 151. Plate part; 152. Post part; 160. Insulating protective cover; 161. Second receiving space; 162. Second bottom wall; 163. Second side wall; 1631. Second support surface; 170. Conductive connecting piece; 171. First connecting plate; 172. Second connecting plate; 180. Sealing element;

[0045] 200, electrode group; 210, first protrusion; 211, first step; 2111, first step surface; 2112, second step surface; 220, second protrusion; 230, electrode tab; 230a, negative electrode tab; 230b, positive electrode tab; 240, insulating film;

[0046] 300, casing; 400, positive electrode cover; 410, second electrode post; 500, end plate. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0049] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0050] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0051] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0053] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0054] like Figures 1-6 As shown, this embodiment provides an assembly structure for an electrode assembly and a cover plate. This assembly structure improves the space utilization of the electrode assembly 200, increases its volume, and facilitates increased cell capacity. It also adapts to the cell cover plate 100, which provides good protection for the integrated connecting block 130, second plastic part 120, and first electrode post 150, preventing damage during transportation and assembly processes and avoiding performance, safety, or appearance defects in the cell. Furthermore, the cell cover plate 100 reduces space occupation, facilitates cell assembly, and achieves a high PCAK assembly rate.

[0055] Specifically, the assembly structure of the electrode assembly and cover plate includes a cell cover plate 100 and an electrode assembly 200. The cell cover plate 100 includes a cover plate body 110 and a first plastic part 140. The first plastic part 140 is disposed on one side of the cover plate body 110 along a first direction and faces the electrode assembly 200. Support portions 142 are provided at both ends of the first plastic part 140 along a second direction, and the interior of each support portion 142 is hollow, forming a first accommodating space 1421. The electrode assembly 200 has two first protrusions 210 on the side facing the cell cover plate 100. Each first protrusion 210 extends along the first direction and is partially accommodated within the first accommodating space 1421 of its corresponding support portion 142. The support portion 142 includes a first bottom wall 1422, which abuts against the end face of the first protrusion 210 facing the cell cover plate 100. Therefore, through the cooperation of the support portion 142 and the first protrusion 210, good positioning between the first plastic part 140 and the electrode assembly 200 can be achieved, resulting in high assembly accuracy. The insertion direction and position of the electrode assembly 200 are less prone to shifting. Simultaneously, the increased volume of the electrode assembly 200 helps to improve the cell capacity. Furthermore, when the cell cover plate 100 presses the electrode assembly 200 into the casing, the first bottom walls 1422 of the two support portions 142 can provide balanced pressure on both ends of the electrode assembly 200 along the second direction, which helps protect the electrode assembly 200 from damage and results in a high assembly yield. The aforementioned first direction is... Figure 1 The Z-axis direction shown is the second direction. Figure 1 The X-axis direction is shown in the figure.

[0056] The cell cover 100 includes a first terminal post 150 and an insulating protective cover 160. The post portion 152 of the first terminal post 150 passes through the first plastic part 140 and the cover body 110 in sequence. The plate portion 151 of the first terminal post 150 is located on the side of the first plastic part 140 facing away from the cover body 110. The insulating protective cover 160 is bonded to the end face of the plate portion 151 facing the electrode assembly 200, and the insulating protective cover 160 abuts against the end of the electrode assembly 200 facing the cell cover 100 (see...). Figure 10 The insulating protective cover 160 insulates the electrode assembly 200 from the cover plate body 110, preventing the risk of short circuits. It is important to note that the insulating protective cover 160 is made of a material with excellent insulation properties and resistance to electrolyte corrosion, thus ensuring a long service life. For example, the insulating protective cover 160 can be made of MPP (microporous foamed polypropylene).

[0057] Furthermore, a second protrusion 220 is provided at one end of the electrode assembly 200 facing the cell cover plate 100. The second protrusion 220 is located at the middle position of the electrode assembly 200 along the second direction. The interior of the insulating protective cover 160 is hollow to form a second accommodating space 161. The second protrusion 220 extends along the first direction and is partially accommodated in the second accommodating space 161. The insulating protective cover 160 includes a second bottom wall 162, which abuts against the end face of the second protrusion 220 facing the cell cover plate 100. Through the cooperation of the insulating protective cover 160 and the second protrusion 220, on the one hand, good positioning between the insulating protective cover 160 and the electrode group 200 can be achieved, with high assembly accuracy. The insertion direction and position of the electrode group 200 are not easily shifted. While fixing the electrode group 200 more firmly, the volume of the electrode group 200 is increased, which is conducive to improving the energy density of the battery cell and storing more energy. On the other hand, when the battery cell cover plate 100 presses the electrode group 200 into the casing, the second bottom wall 162 of the insulating protective cover 160 can provide support for the middle position of the electrode group 200 in the width direction (i.e., the second direction), improving its resistance to deformation. Furthermore, the force on the electrode group 200 at various positions along the second direction is more balanced, resulting in a good fixing effect. The electrode group 200 is not easy to move around, which is suitable for some electrode groups 200 with larger width dimensions.

[0058] See also Figure 2Along the second direction, the width of the first protrusion 210 facing the end of the cell cover 100 is W1, and the width of the second protrusion 220 facing the end of the cell cover 100 is W2. The relationship between W1 and W2 satisfies: 22mm ≤ 2W1 + W2 ≤ 138mm. For example, the value of 2W1 + W2 can be 22mm, 40mm, 60mm, 80mm, 100mm, or 138mm, etc. By limiting the value of 2W1 + W2 to meet the above size limit, it is ensured that the contact area between the first plastic part 140 and the insulating protective cover 160 and the electrode group 200 is large, and the pressure on the first protrusion 210 and the second protrusion 220 of the electrode group 200 is small, making it less likely to be damaged by pressure or break.

[0059] Optionally, the value range of W1 is: 8.5mm≤W1≤54mm. The value range of W2 is: 5mm≤W2≤30mm. It should be noted that the values ​​of W1 and W2 should not be too small, otherwise the width of the first protrusion 210 and the second protrusion 220 along the second direction will be small, the connection strength between the first protrusion 210 and the second protrusion 220 and the main body of the electrode group 200 will be low, and it will be easy to break under stress, resulting in damage to the electrode group 200 and a decrease in assembly yield. The values ​​of W1 and W2 should also not be too large, otherwise the width of the first protrusion 210 and the second protrusion 220 along the second direction will be too large, which will occupy a lot of space and affect the arrangement of other structural components on the cell cover plate 100 (e.g., conductive connecting piece 170, etc.).

[0060] Along the first direction, the first protrusion 210 extends toward the cell cover 100 at a height of H1, and the second protrusion 220 extends toward the cell cover 100 at a height lower than that of the first protrusion 210. The value of H1 is in the range of 5mm ≤ H1 ≤ 7mm. For example, the value of H1 can be 5mm, 6mm, or 7mm, etc. By limiting the value of H1 to meet the above size restrictions, it is ensured that the first protrusion 210 and the second protrusion 220 can effectively increase the volume of the electrode group 200, make reasonable use of the internal space of the cell, and at the same time play a good positioning role for the electrode group 200, preventing the electrode group 200 from shifting.

[0061] See also Figure 3 , Figure 4 ,as well as Figures 8-10In this embodiment, the first protrusion 210 of the pole assembly 200 has a first step 211 circumferentially provided. The support portion 142 includes a first sidewall 1423 adjacent to the first bottom wall 1422. The inner wall surface of the first sidewall 1423 is in clearance fit with the first step surface 2111 of the first step 211. The end face of the first sidewall 1423 facing the pole assembly 200 is a first support surface 1424, which is in clearance fit with the second step surface 2112 of the first step 211. This allows the first protrusion 210 to be smoothly assembled with the support portion 142, reducing the likelihood of interference or scratches to the first protrusion 210. Furthermore, the engagement between the support portion 142 and the first step 211 of the first protrusion 210 improves the positioning accuracy between them, resulting in higher assembly precision and reducing the likelihood of displacement of the pole assembly 200. The insulating protective cover 160 includes a second side wall 163 adjacent to the second bottom wall 162, and the inner wall surface of the second side wall 163 is clearance-fitted with the circumferential side wall of the second protrusion 220. This allows the second protrusion 220 to be smoothly assembled with the insulating protective cover 160, minimizing the risk of interference or scratches to the second protrusion 220.

[0062] Of course, in some embodiments, the second protrusion 220 may have a second step (not shown in the figure) circumferentially. The inner wall surface of the second sidewall 163 of the insulating protective cover 160 is in clearance fit with the third step surface of the second step. The end face of the second sidewall 163 facing the electrode assembly 200 is the second support surface 1631, and the second support surface 1631 is in clearance fit with the fourth step surface of the second step. This allows the second protrusion 220 and the insulating protective cover 160 to be smoothly assembled, and the engagement between the insulating protective cover 160 and the second step of the second protrusion 220 improves the positioning accuracy between them, resulting in higher assembly accuracy and preventing the electrode assembly 200 from shifting.

[0063] See also Figure 4 In this embodiment, the first protrusion 210 along the third direction ( Figure 1 The distance between the two opposing first step surfaces 2111 (in the Y-axis direction shown) is L1, and the thickness of the pole group 200 along the third direction is L2. The relationship between L1 and L2 satisfies: 1.25mm ≤ (L2-L1) / 2 ≤ 3mm. That is, along the third direction, the width of the second step surface 2112 is (L2-L1) / 2. For example, the value of (L2-L1) / 2 can be 1.25mm, 1.5mm, 2.0mm, 2.5mm, or 3mm, etc. By limiting the value of (L2-L1) / 2 to the above range, the width of the second step surface 2112 is ensured to be appropriate. On the one hand, this facilitates the processing of the first step 211 and makes it easy to form; on the other hand, it avoids the distance between the two opposing first step surfaces 2111 of the first protrusion 210 along the third direction being too close, and the side of the first protrusion 210 facing the support 142 being too sharp, which would easily be damaged under pressure.

[0064] Optionally, the value range of L1 is 12mm ≤ L1 ≤ 16mm, and the value range of L2 is 16mm ≤ L2 ≤ 20mm. For example, when the value of L1 is 12mm, the value of L2 can be 16mm, 17mm, or 18mm, etc. When the value of L1 is 16mm, the value of L2 can be 18.5mm, 19mm, or 20mm, etc.

[0065] Further, see Figure 4 and Figure 6 The electrode assembly 200 has two tabs 230 at one end facing the cell cover plate 100. The two tabs 230 are arranged opposite each other on both sides of the second protrusion 220 along the second direction, and both tabs 230 are eccentrically arranged along the third direction. By eccentrically arranging the tabs 230, it is easier to weld the tabs 230 to the conductive connecting piece 170 on the cell cover plate 100, and the length of the tabs 230 extending out of the electrode assembly 200 can be relatively shortened, thereby protecting the tabs 230 from tearing.

[0066] Optionally, along a third direction, the distance between the end face of the tab 230 near the center of the electrode assembly 200 in the thickness direction and the end face of the electrode assembly 200 away from the tab 230 is L3, and the relationship between L2 and L3 satisfies: 0.58 ≤ L3 / L2 ≤ 0.75. For example, the value of L3 / L2 can be 0.58, 0.60, 0.70, or 0.75, etc. By limiting the value of L3 / L2 within the above range, the appropriate arrangement position of the tab 230 is ensured. Otherwise, when the value of L3 / L2 is too small, the tab 230 needs to be bent when welding the tab 230 to the conductive connecting piece 170. The shape of the tab 230 is not easy to guarantee, and the tab 230 needs to be set too long, which is prone to tearing, reducing the reliability of the cell. When the value of L3 / L2 is too large, the tab 230 is too close to the edge of the electrode group 200 along the third direction, which is not conducive to processing. In addition, the arrangement space of the conductive connecting piece 170 is limited, and interference may occur when the cell cover plate 100 and the housing 300 are pressed together, reducing the assembly yield.

[0067] For example, the value range of L3 is: 10mm ≤ L3 ≤ 14mm. For instance, when the value of L2 is 16mm, the value of L3 can be 10mm, 11mm, or 12mm, etc. When the value of L1 is 20mm, the value of L3 can be 12mm, 13.5mm, or 14mm, etc.

[0068] Furthermore, the cell cover 100 includes two conductive connecting pieces 170, which are respectively disposed on both sides of the insulating protective cover 160 along the second direction. Each conductive connecting piece 170 has its two ends electrically connected to the plate body 151 of the first electrode post 150 and an electrode tab 230, respectively. The insulating protective cover 160 provides good insulation protection for the electrode tabs 230 and conductive connecting pieces 170 on both sides, avoiding the risk of overlap between the two electrode tabs 230 or the two conductive connecting pieces 170, ensuring stable current output, and excellent charging and discharging performance of the cell. Optionally, the conductive connecting pieces 170 can be made of copper. The conductive connecting pieces 170 include a first connecting plate 171 and a second connecting plate 172 connected to each other. The first connecting plate 171 and the second connecting plate 172 are perpendicular and form an L-shaped structure. The first connecting plate 171 is connected to the plate body 151, and the second connecting plate 172 is stacked and connected to the electrode tab 230 along the third direction. This achieves conductive connection between the electrode group 200 and the first electrode post 150.

[0069] See also Figure 5 , Figure 6 and Figure 10 The cell cover 100 includes a second plastic part 120 and a connecting block 130. The second plastic part 120 is disposed on the side of the cover body 110 opposite to the first plastic part 140. The connecting block 130 is disposed on the side of the second plastic part 120 away from the cover body 110. The column portion 152 of the first electrode post 150 passes through the plastic part body 141 of the first plastic part 140, the cover body 110, the second plastic part 120, and the connecting block 130 in sequence, and is then riveted to the connecting block 130. The cover body 110 has a groove 1131 on the side facing the second plastic part 120, and the second plastic part 120 and the connecting block 130 are recessed in the groove 1131. The arrangement of the first plastic part 140 and the second plastic part 120 ensures good insulation between the electrode group 200, the first electrode post 150, and the cover body 110. Optionally, the first plastic part 140 and the second plastic part 120 can be made of PP material.

[0070] As an optional embodiment, the cover body 110 includes two first panels 111, two transition plates 112, and one second panel 113. The two transition plates 112 are located on opposite sides of the second panel 113 along its length (i.e., the second direction), and each transition plate 112 connects to one first panel 111. Along the first direction, there is a height difference between the first panels 111 and the second panel 113, thereby forming the aforementioned groove 1131. The bottom wall of the groove 1131 is the end face of the second panel 113 facing away from the first plastic part 140. The second plastic part 120 is fitted to the end face of the second panel 113 facing away from the first plastic part 140, and the connecting block 130 is at least partially accommodated within the receiving groove 121 of the second plastic part 120, achieving precise positioning between the connecting block 130 and the second plastic part 120. Furthermore, after the connecting block 130 and the second plastic part 120 are placed in the groove 1131 of the cover plate body 110, the end face of the connecting block 130 facing away from the first plastic part 140 is lower than the end face of the first panel 111 facing away from the first plastic part 140, thereby effectively protecting the connecting block 130 and the first terminal post 150 from damage during the manufacturing process of the cell cover plate 100. Simultaneously, during cell assembly, the end face of the connecting block 130 facing away from the first plastic part 140 is lower than the end face of the first panel 111 facing away from the first plastic part 140, allowing the conductive busbar connecting two adjacent cells to also be accommodated in the groove 1131. The end face of the conductive busbar facing away from the first plastic part 140 is lower than the end face of the first panel 111 facing away from the first plastic part 140, saving assembly space and improving the assembly rate of the battery module. It should be noted that the battery module is formed by connecting multiple cells in series and parallel via conductive busbars. For example, the height difference between the first panel 111 and the second panel 113 can be formed by mechanical bending. In order to make the transition between the first panel 111 and the second panel 113 smoother and more gradual, the transition plate 112 can be arranged at an angle relative to the second panel 113.

[0071] Furthermore, a reinforcing rib 1132 is provided on the end face of the second panel 113 facing the second plastic part 120. The reinforcing rib 1132 extends along the second direction, and a transition plate 112 is connected to each end of the reinforcing rib 1132. The arrangement of the reinforcing rib 1132 improves the mechanical strength and structural strength of the cover plate body 110, making the structure of the cover plate body 110 more stable and less prone to deformation.

[0072] The cell cover 100 also includes a sealing element 180, which is sleeved on the outer side of the cylindrical portion 152 of the first electrode post 150, sealing the gap between the cylindrical portion 152 of the first electrode post 150 and the cover body 110. The sealing element 180 ensures excellent sealing and insulation performance of the cell cover 100, resulting in high safety and preventing electrolyte leakage.

[0073] Optionally, in some embodiments, the plastic body 141 of the first plastic part 140 is further provided with a limiting groove 1411. The limiting groove 1411 is located on the end face of the plastic body 141 facing the electrode group 200, and the plate portion 151 of the first electrode post 150 is embedded in the limiting groove 1411. Through the cooperation between the plate portion 151 and the limiting groove 1411, precise positioning between the first plastic part 140 and the first electrode post 150 is achieved, resulting in high assembly accuracy. At the same time, the setting of the limiting groove 1411 also reduces the thickness of the cell cover 100 along the first direction, which is conducive to the thinner and lighter design of the cell cover 100 and saves space.

[0074] This embodiment also provides a battery cell, see [link to example]. Figures 7-10 The battery cell includes a cell cover plate 100, an electrode assembly 200, and a housing 300. The electrode assembly 200 is disposed within the housing 300, and the cell cover plate 100 is encapsulated at the opening of the housing 300. The electrode assembly 200 and the cell cover plate 100 are connected using the aforementioned electrode assembly and cover plate assembly structure. This battery cell has a large capacity and is easy to group with other battery cells, facilitating arrangement, saving assembly space, and achieving a high module grouping rate.

[0075] Optionally, the battery cell in this embodiment can be a blade battery cell, including an electrode assembly 200, a housing 300, a negative electrode cover plate, and a positive electrode cover plate 400. The housing 300 has openings at both ends along a first direction, and the negative electrode cover plate and the positive electrode cover plate 400 are respectively disposed at one opening of the housing 300. The electrode assembly 200 is installed inside the housing 300, and positive electrode tabs 230b and negative electrode tabs 230a are respectively led out from both ends of the electrode assembly 200 along the first direction. The negative electrode cover plate is the aforementioned battery cell cover plate 100. The electrode assembly 200 has two negative electrode tabs 230a and one positive electrode tab 230b. The two negative electrode tabs 230a are respectively connected to two conductive connecting pieces 170 on the battery cell cover plate 100. The positive electrode tab 230b is conductively connected to the second terminal post 410 on the positive electrode cover plate 400. Furthermore, the blade battery cell also includes an end plate 500, which is sandwiched between the positive electrode cover plate 400 and the electrode assembly 200 for fixing the electrode assembly 200. An insulating film 240 is provided on the outside of the electrode assembly 200 to insulate the electrode assembly 200 from the housing 300.

[0076] In other embodiments, the battery cell may also be a prismatic cell, including an electrode assembly 200, a housing 300, and the aforementioned cell cover plate 100. The housing 300 has an opening at one end along a first direction, and the cell cover plate 100 is disposed at the opening of the housing 300. The electrode assembly 200 is installed inside the housing 300, and a positive electrode tab 230b and a negative electrode tab 230a are led out from the same end of the electrode assembly 200 along the first direction. Two first electrode posts 150 are integrated on the cell cover plate 100, and the plate portion 151 of each first electrode post 150 is individually connected to a conductive connecting piece 170. The positive electrode tab 230b and the negative electrode tab 230a are each connected to a conductive connecting piece 170.

[0077] The following specific implementation examples verify the relevant dimensional design of the electrode group 200 of the above-mentioned battery cell. See Table 1 for details.

[0078] Table 1

[0079]

[0080] As can be seen from the above results, the value ranges of parameters L1, L2, L3, (L2-L1) / 2, L3 / L2, H1, and 2W1+W2 in Examples 1 to 6 meet their corresponding size constraints. When the cell cover plate 100 presses the electrode group 200 into the casing, it can apply pressure evenly to the electrode group 200. After the cell is assembled, the electrode group 200 and the tab 230 are undamaged, and the tab 230 does not experience any short circuit. The cell assembly yield is high, and the product is good.

[0081] In Example 7, the value of parameter (L2-L1) / 2 is less than the minimum value of 1.25mm≤(L2-L1) / 2≤3mm. The width of the second step surface 2112 on the first protrusion 210 in the pole group 200 is too small, and it cannot form an effective positioning with the first support surface 1424 of the support part 142. Moreover, the processing error is large, the assembly yield of the battery cell decreases, and the product is defective.

[0082] In Example 8, the value of parameter (L2-L1) / 2 is greater than the maximum value of 1.25mm≤(L2-L1) / 2≤3mm. The width of the second step surface 2112 on the first protrusion 210 in the electrode group 200 is too large. The volume of the first protrusion 210 in the electrode group 200 is small, which does not have an obvious effect on increasing the cell capacity and is not conducive to increasing the cell capacity. In addition, the mechanical strength of the first protrusion 210 decreases, making it easy to break and separate from the body of the electrode group 200, resulting in product defects.

[0083] In Example 9, the value of parameter 2W1+W2 is less than the minimum value of 22mm≤2W1+W2≤138mm. At this time, the dimensions of the first protrusion 210 and the second protrusion 220 along the second direction are too small. When the electrode assembly 200 is inserted into the casing by the cell cover plate 100, the electrode assembly 200 is easily squeezed and deformed, increasing the risk of damage to the electrode assembly 200, resulting in a low assembly yield of the cell and defective products.

[0084] In Example 10, the value of parameter 2W1+W2 is greater than the maximum value of 22mm≤2W1+W2≤138mm. At this time, the dimensions of the first protrusion 210 and the second protrusion 220 along the second direction are too large, occupying a large space. The arrangement space of the tab 230 and the conductive connecting piece 170 is small, and the size of the tab 230 needs to be reduced. This cannot meet the overcurrent requirements of some high-current cells, resulting in product defects.

[0085] In Example 11, the value of parameter L3 / L2 is less than the minimum value of 0.58 ≤ L3 / L2 ≤ 0.75. At this time, the tab 230 is not sufficiently eccentric along the third direction, the length of tab 230 required for welding tab 230 to conductive connecting piece 170 is too long, the shape of tab 230 inside the cell is not good, and defects such as deformation and tearing of tab 230 are prone to occur, resulting in a low assembly yield of the cell and defective products.

[0086] In Example 12, the value of parameter L3 / L2 is greater than the maximum value of 0.58 ≤ L3 / L2 ≤ 0.75. At this time, the tab 230 is excessively eccentric along the third direction, and problems such as tearing and large dimensional fluctuations are likely to occur when the tab 230 is closed, resulting in product defects.

[0087] Taking all factors into consideration, when the dimensions of the cell cover plate 100 meet the above-mentioned dimensional requirements, it can be ensured that the cell cover plate 100 applies pressure evenly to the electrode group 200, and the electrode group 200 and the tab 230 are not damaged during the pressing process, resulting in a high assembly yield of the cell. At the same time, it also meets the space requirements for the arrangement of the tab 230 and the conductive connecting piece 170, meets the overcurrent requirements of the high-current cell, and the volume of the electrode group 200 can be effectively increased, thus improving the capacity of the cell.

[0088] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An assembly structure for an electrode assembly and a cover plate, characterized in that, include: A battery cell cover plate, the battery cell cover plate including a cover plate body and a first plastic part, the first plastic part being disposed on one side of the cover plate body along a first direction, and the first plastic part having support portions at both ends along a second direction, the support portions being hollow to form a first accommodating space; The electrode assembly has two first protrusions on one side facing the cell cover plate. Each first protrusion extends along a first direction and is partially accommodated in the first accommodating space of a support portion. The support portion includes a first bottom wall that abuts against the end face of the first protrusion facing the cell cover plate.

2. The assembly structure of the electrode assembly and cover plate according to claim 1, characterized in that, The cell cover includes a first electrode post and an insulating protective cover. The post portion of the first electrode post passes through the first plastic part and the cover body in sequence. The plate portion of the first electrode post is located on the side of the first plastic part away from the cover body. The insulating protective cover is adhered to the end face of the plate portion facing the electrode group and abuts against the end of the electrode group facing the cell cover.

3. The assembly structure of the electrode assembly and cover plate according to claim 2, characterized in that, The electrode assembly is further provided with a second protrusion at one end facing the cell cover plate. The second protrusion is located at the middle position of the electrode assembly along the second direction. The interior of the insulating protective cover is hollow to form a second accommodating space. The second protrusion extends along the first direction and is partially accommodated in the second accommodating space. The insulating protective cover includes a second bottom wall, which abuts against the end face of the second protrusion facing the cell cover plate. In this context, along two directions, the width of the first protrusion facing one end of the battery cell cover is W1, and the width of the second protrusion facing one end of the battery cell cover is W2. The relationship between W1 and W2 satisfies: 22mm≤2W1+W2≤138mm; The value range of W1 is: 8.5mm≤W1≤54mm; The value range of W2 is: 5mm≤W2≤30mm.

4. The assembly structure of the electrode assembly and cover plate according to claim 3, characterized in that, The first protrusion is provided with a first step in the circumferential direction. The support part includes a first side wall adjacent to the first bottom wall. The inner wall surface of the first side wall is in clearance fit with the first step surface of the first step. The end face of the first side wall facing the pole group is a first support surface. The first support surface is in clearance fit with the second step surface of the first step. And / or, the second protrusion is provided with a second step in the circumferential direction, the insulating protective cover includes a second side wall adjacent to the second bottom wall, the inner wall surface of the second side wall is in clearance fit with the third step surface of the second step, the end face of the second side wall facing the pole group is a second support surface, and the second support surface is in clearance fit with the fourth step surface of the second step.

5. The assembly structure of the electrode assembly and cover plate according to claim 4, characterized in that, The distance between the two first step surfaces that are opposite each other in the third direction in the first protrusion is L1, and the thickness of the pole group in the third direction is L2; The relationship between L1 and L2 satisfies: 1.25mm≤(L2-L1) / 2≤3mm; The value range of L1 is: 12mm≤L1≤16mm; The value range of L2 is: 16mm≤L2≤20mm.

6. The assembly structure of the electrode assembly and cover plate according to claim 5, characterized in that, The electrode group has two tabs at one end facing the cell cover plate. The two tabs are arranged opposite each other on both sides of the second protrusion along the second direction, and both tabs are eccentrically arranged along the third direction. Wherein, along the third direction, the distance between the end face of the electrode tab near the center of the electrode group in the thickness direction and the end face of the electrode group away from the electrode tab is L3; The relationship between L2 and L3 satisfies: 0.58 ≤ L3 / L2 ≤ 0.75; The value range of L3 is: 10mm≤L3≤14mm.

7. The assembly structure of the electrode assembly and cover plate according to claim 6, characterized in that, The cell cover plate includes two conductive connecting pieces, which are respectively disposed on both sides of the insulating protective cover. The two ends of each conductive connecting piece are electrically connected to the plate body and an electrode tab, respectively.

8. The assembly structure of the electrode assembly and cover plate according to claim 7, characterized in that, The conductive connecting piece includes a first connecting plate and a second connecting plate, the first connecting plate and the second connecting plate are perpendicular to each other, the first connecting plate is connected to the plate body, and the second connecting plate is connected to the electrode tab.

9. The assembly structure of the electrode assembly and cover plate according to claim 2, characterized in that, The cell cover plate includes a second plastic part and a connecting block. The second plastic part is disposed on the side of the cover plate body opposite to the first plastic part. The connecting block is disposed on the side of the second plastic part away from the cover plate body. The column portion passes through the first plastic part, the cover plate body, the second plastic part and the connecting block in sequence and is riveted to the connecting block. The cover plate body has a groove on the side facing the second plastic part, and the second plastic part and the connecting block are recessed in the groove.

10. A battery cell, characterized in that, The device includes an electrode assembly, a cell cover, and a housing. The electrode assembly is disposed within the housing, and the cell cover is encapsulated at the opening of the housing. The electrode assembly and the cell cover are connected using the electrode assembly and cover assembly structure described in any one of claims 1-9.

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