Battery cell cover plate and battery cell

Abstract

The present invention relates to the technical field of batteries, and provides a battery cell cover plate and a battery cell, the battery cell cover plate comprises: a cover plate body provided with a vent hole; the anti-explosion valve is mounted on the cover plate body and is opposite to the exhaust hole; the insulating part comprises a fixing plate and a turnover plate, the fixing plate is located on one side of the cover plate body and provided with two supporting parts which protrude towards the side away from the cover plate body and are arranged in the length direction of the cover plate body in a spaced mode, one end of the turnover plate is connected to one supporting part in a turnover mode, and the turnover plate can be buckled or opened relative to the fixing plate; the pole penetrates through the cover plate body and the fixing plate in the thickness direction of the cover plate body, and the pole and the anti-explosion valve are located between the two supporting parts; when the turnover plate is buckled on the fixing plate, the turnover plate covers the pole column, the other end of the turnover plate is connected with the other supporting part, the exhaust hole, the first exhaust structure of the fixing plate and the second exhaust structure of the turnover plate are communicated, and the supporting part and the turnover plate are both suitable for abutting against the pole group. According to the battery cell cover plate, the fixing effect of the insulating part on the pole group is improved, and the pole group is prevented from moving.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a cell cover and a cell. Background Technology

[0002] Lithium-ion batteries are widely used in various fields such as transportation power supply, power storage, new energy storage power supply, aerospace and military industry due to their advantages such as large capacity, high operating voltage, strong charge retention capability and long cycle life.

[0003] The battery cell is the smallest unit of a lithium battery pack. In existing technologies, a battery cell structure generally consists of an electrolyte, electrode assembly, bare cell insulating film, cell cover, and cell casing. The cell cover is an assembly comprising a cover body, an insulating component, and terminals. The cover body is welded to the cell casing, forming a closed space to accommodate the electrode assembly. The insulating component is located inside the cover body and serves as insulation between the cover body and the electrode assembly. The terminals are welded to the electrode assembly's tabs. The insulating component is typically thickened to press down on the electrode assembly while allowing space between the cell cover and the electrode assembly to accommodate the electrode tabs. However, the small contact area between the insulating component and the electrode assembly results in poor electrode assembly fixation. When the cell is subjected to external impact, the electrode assembly is prone to shifting, leading to damage to the electrode assembly by the terminal base and tearing of the tabs, thus affecting the cell's safety. Summary of the Invention

[0004] This invention provides a cell cover plate and a cell to solve the problem in the prior art where the cell cover plate has a poor fixing effect on the electrode assembly and the electrode assembly is prone to shifting.

[0005] This invention provides a battery cell cover plate, comprising: The cover plate body is equipped with vent holes; An explosion-proof valve is installed on the cover plate body and is opposite to the vent hole; An insulating component includes a fixed plate and a folding plate. The fixed plate is located on one side of the cover plate body and has two support portions protruding away from the cover plate body. The two support portions are spaced apart along the length of the cover plate body. One end of the folding plate is folded and connected to one of the support portions, so that the folding plate can be fastened or opened relative to the fixed plate. The fixed plate is provided with a first venting structure, and the folding plate is provided with a second venting structure. The pole is inserted through the cover plate body and the fixing plate along the thickness direction of the cover plate body, and the pole and the explosion-proof valve are located between the two support parts in the length direction; When the folding plate is fastened to the fixing plate, the vent hole, the first vent structure and the second vent structure are connected, the folding plate covers the pole post and its other end is connected to another support part, and both the support part and the folding plate are adapted to abut against the pole group of the battery cell.

[0006] According to a battery cell cover plate provided by the present invention, in the thickness direction, the projection of the vent hole is located within the projection distribution range of the first vent structure, and the projection of the first vent structure is located within the projection distribution range of the second vent structure.

[0007] According to a battery cell cover plate provided by the present invention, the first venting structure includes a plurality of first through holes spaced apart from each other, the second venting structure includes a plurality of second through holes spaced apart from each other, the area of ​​the venting holes is S1, and the area of ​​the venting holes, the plurality of first through holes and the plurality of second through holes overlapping in the thickness direction is S4, and S4 / S1≥0.8.

[0008] According to the present invention, in the length direction of the cover plate body, the size of the vent hole is A1, the size of the distribution area of ​​the first vent structure on the fixed plate is A2, the size of the distribution area of ​​the second vent structure on the folding plate is A3, 1.05≤A2 / A1≤1.2, 1.05≤A3 / A2≤1.2; And / or, in the width direction of the cover plate body, the size of the vent hole is B1, the size of the distribution area of ​​the first vent structure on the fixed plate is B2, the size of the distribution area of ​​the second vent structure on the folding plate is B3, 1.05≤B2 / B1≤1.2, 1.05≤B3 / B2≤1.2; And / or, the area of ​​the exhaust hole is S1, the area of ​​the distribution area of ​​the first exhaust structure on the fixed plate is S2, the area of ​​the distribution area of ​​the second exhaust structure on the folding plate is S3, 1.2≤S3 / S2≤1.5, 1.2≤S2 / S1≤1.5.

[0009] According to a battery cell cover plate provided by the present invention, the cover plate body is provided with a boss protruding away from the insulating member, and the electrode post is spaced apart from the boss in the length direction.

[0010] According to a battery cell cover plate provided by the present invention, the boss includes a plurality of protrusions stacked sequentially along the thickness direction of the cover plate body, and the vent hole is disposed in the topmost protrusion.

[0011] According to the present invention, a battery cell cover plate is provided, the cover plate body includes a base plate portion and a bending portion, the two ends of the bending portion are respectively connected to the base plate portion in the length direction, the bending portion is bent relative to the base plate portion to form the boss, and the two pole posts are correspondingly inserted into the two base plate portions.

[0012] According to a battery cell cover plate provided by the present invention, a recess is formed on the side of the cover plate body near the insulating member corresponding to the position of the boss, the fixing plate cooperates with the recess, and a groove is formed on the side of the fixing plate away from the cover plate body corresponding to the position of the recess; when the folding plate is fastened to the fixing plate, a recess is formed on the side of the folding plate away from the fixing plate corresponding to the position of the groove.

[0013] A cell cover plate provided by the present invention further includes: A connecting piece is located between the fixed plate and the folding plate. The connecting piece includes a connected base portion and an extension portion. The base portion is connected to the pole post, and the extension portion is located in the groove for welding to the pole lug of the pole assembly. When the folding plate is fastened to the fixed plate, the folding plate covers the base portion and the extension portion.

[0014] The present invention also provides a battery cell, comprising: The battery cell casing has an opening; The cell cover plate as described in any one of claims 1 to 7, wherein the cell cover plate is disposed at the opening and surrounds the cell housing to form a receiving cavity; An electrode assembly is disposed within the receiving cavity, and the welding portion of the electrode lug of the electrode assembly is located between the fixing plate and the folding plate and is welded to the electrode post.

[0015] The present invention provides a cell cover and a cell, which, by incorporating an insulating component with a fixed plate and a folding plate, includes a support portion on the fixed plate for contact with the electrode assembly. The folding plate is folded and connected to the support portion, allowing the folding plate to be engaged or disengaged relative to the fixed plate. When the folding plate is engaged with the fixed plate, both the folding plate and the support portion can simultaneously contact the electrode assembly of the cell, increasing the contact area between the insulating component and the electrode assembly, improving the fixing effect of the insulating component on the electrode assembly, thereby preventing electrode movement, preventing the base of the electrode post from damaging the electrode assembly, and preventing the electrode tabs from being pulled, thus improving the safety performance of the cell. Furthermore, when the folding plate is engaged with the fixed plate, it can simultaneously fill the height difference between the two support portions and the contact portion, which is beneficial for improving assembly efficiency. The second venting structure on the folding plate facilitates the venting of the explosion-proof valve. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the battery cell cover plate provided by the present invention.

[0018] Figure 2 yes Figure 1 A schematic diagram of the battery cell cover from another perspective.

[0019] Figure 3 This is a schematic diagram of the structure of the cover plate body in the battery cell cover plate provided by the present invention.

[0020] Figure 4 yes Figure 2 A schematic diagram showing the folding plate of the battery cell cover in the open state.

[0021] Figure 5 This is a schematic diagram of the structure of the insulating component in the battery cell cover provided by the present invention.

[0022] Figure 6 This is a side view of the battery cell cover plate provided by the present invention.

[0023] Figure 7 This is a partial structural schematic diagram of the battery cell cover plate provided by the present invention.

[0024] Figure 8 This is a schematic diagram of the assembly process of the battery cell cover plate and electrode assembly provided by the present invention.

[0025] Figure 9 This is a schematic diagram of the assembly structure of the battery cell cover plate and electrode assembly provided by the present invention.

[0026] Figure 10 This is a schematic diagram of the electrode assembly of the battery cell provided by the present invention.

[0027] Figure 11 yes Figure 10 A schematic diagram of the pole group from another perspective.

[0028] Figure label: 1. Cover plate body; 11. Boss; 111. First protrusion; 112. Second protrusion; 113. Reinforcing rib; 12. Base plate; 121. Reference surface; 21. Pole post; 22. Connecting piece; 221. Base; 222. Extension; 3. Explosion-proof valve; 4. Insulating component; 40. Recess; 401. First groove; 402. Second groove; 41. Fixing plate; 410. Groove; 411. Fitting part; 4111. First fitting plate; 4112. Second fitting plate; 4113. Third fitting plate; 41131. First Exhaust structure; 4114, First connecting plate; 4115, Second connecting plate; 412, Support part; 4121, Slot; 42, Folding plate; 421, First plate body; 422, Second plate body; 423, Third plate body; 4231, Second exhaust structure; 424, Third connecting plate; 425, Limiting plate; 426, Fourth connecting plate; 43, Notch; 5, Electrode assembly; 50, Connecting end face; 51, Electrode lug; 52, Protrusion; 521, First groove; 522, Second groove; 5201, Top surface; 5202, Side surface. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "first"..."fourth" are numbering for the purpose of clearly identifying product components and do not represent any substantial difference. The terms "installed," "connected," and "linked" 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 direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances. Furthermore, "multiple" means two or more. In the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0031] The following is combined with Figures 1-11 The present invention describes the cell cover plate and the cell.

[0032] like Figure 1 , Figure 2 and Figure 4As shown, the battery cell cover provided in this embodiment of the invention includes a cover body 1, an explosion-proof valve 3, an insulating component 4, and a terminal post 21. The cover body 1 is provided with a vent hole. The explosion-proof valve 3 is installed on the cover body 1 and is opposite to the vent hole. The insulating component 4 includes a fixing plate 41 and a folding plate 42. The fixing plate 41 is located on one side of the cover body 1 and has two support portions 412 protruding away from the cover body 1. The two support portions 412 are spaced apart along the length direction of the cover body 1, and one end of the folding plate 42 is folded and connected to one of the support portions 412, so that the folding plate 42 can be fastened or opened relative to the fixing plate 41. The fixing plate 41 is provided with a first venting structure 41131, and the folding plate 42 is provided with a second venting structure 4231. The terminal post 21 passes through the cover body 1 and the fixing plate 41 along the thickness direction of the cover body 1. In the length direction of the cover body 1, the terminal post 21 and the explosion-proof valve 3 are located between the two support portions 412. When the folding plate 42 is fastened to the fixing plate 41, the exhaust hole, the first exhaust structure 41131 and the second exhaust structure 4231 are connected. The folding plate 42 covers the pole post 21 and its other end is connected to another support part 412. Both the support part 412 and the folding plate 42 are adapted to abut against the pole group 5 of the battery cell.

[0033] The cell cover is applied to the cell, which includes a cell housing, electrode assembly 5, and the cell cover. The cell housing has an opening, and the cell cover is positioned at the opening and surrounds the cell housing to form a receiving cavity. The electrode assembly 5 is disposed within the receiving cavity. The cell housing and the cover body 1 are welded together to form the outer shell of the cell, providing protection for the internal components and withstanding certain external impacts. A terminal post 21 protrudes from the outer surface of the cover body 1 to form a terminal terminal, used for connection to a busbar, allowing multiple cells to be connected via the busbar to form a battery module. The other end of the terminal post 21 is located within the receiving cavity and connected to the tab 51 of the terminal post 21. The battery module is assembled into a housing to form a battery pack.

[0034] For the length and width directions of the cover plate body 1, please refer to [reference needed]. Figure 1 The thickness direction of the cover plate body 1 is perpendicular to the length and width directions. Specifically, the cover plate body 1 has a first side and a second side opposite to each other in its thickness direction. The first side faces the outside of the cell, and the pole post 21 protrudes from the first side to form a pole post terminal. The second side faces the pole group 5 inside the receiving cavity.

[0035] An insulating element 4 is disposed on the second side of the cover plate body 1 for insulating and isolating the cover plate body 1 and the pole group 5. Specifically, the fixing plate 41 has a fitting portion 411 and a support portion 412 protruding from the fitting portion 411. The fitting portion 411 is fitted to the cover plate body 1, and the support portion 412 protrudes from the side of the fitting portion 411 away from the cover plate body 1, that is, the support portion 412 is a locally thickened portion on the fixing plate 41. The folding plate 42 and the support portion 412 are arranged along the length direction of the cover plate body 1, and one end of the folding plate 42 in the length direction is folded and connected to the support portion 412.

[0036] It is understandable that there is a height difference between the fitting part 411 and the support part 412 in the thickness direction of the cover plate body 1. When the folding plate 42 is fastened to the fixing plate 41, at least a portion of the side of the folding plate 42 away from the fixing plate 41 is flush with the support part 412, so that the support part 412 and the folding plate 42 can simultaneously abut against the pole group 5.

[0037] Optionally, the folding plate 42 has a folded connecting end and a free end opposite to each other in the length direction of the cover plate body 1. The folded connecting end is folded and connected to one support part 412, and the free end overlaps with another support part 412, which helps to ensure that the free end of the folding plate 42 is flush with the other support part 412. Specifically, the other support part 412 is provided with a slot 4121. When the folding plate 42 is fastened to the fixing plate 41, the free end is located in the slot 4121. Optionally, the support part 412 and the free end are upper limit-fitted in the width direction of the cover plate body 1 to ensure accurate positioning of the fastening position of the folding plate 42.

[0038] The cover plate body 1 is provided with an exhaust hole, and the explosion-proof valve 3 is installed on the cover plate body 1 and opposite to the exhaust hole. The first exhaust structure 41131 on the fixing plate 41 is connected to the exhaust hole. When the cell cover plate and the electrode group 5 are assembled, the folding plate 42 is fastened to the fixing plate 41, and the second exhaust structure 4231 on the folding plate 42 is connected to the first exhaust structure 41131 and the exhaust hole. When the cell experiences thermal runaway, the gas inside the cell can flow sequentially through the second exhaust structure 4231, the first exhaust structure 41131 and the exhaust hole to the explosion-proof valve 3, and then be discharged through the explosion-proof valve 3.

[0039] The battery cell cover provided in this embodiment of the invention features an insulating member 4 with a fixed plate 41 and a folding plate 42. The fixed plate 41 has a support portion 412 for contacting the electrode group 5. The folding plate 42 is folded and connected to the support portion 412, allowing the folding plate 42 to be fastened or opened relative to the fixed plate 41. When the folding plate 42 is fastened to the fixed plate 41, both the folding plate 42 and the support portion 412 can simultaneously contact the electrode group 5 of the battery cell, increasing the contact area between the insulating member 4 and the electrode group 5. This improves the fixing effect of the insulating member 4 on the electrode group 5, preventing the electrode group 5 from shifting, preventing the base of the pole post 21 from damaging the electrode group 5, and preventing the pole tab 51 from being pulled, thus improving the safety performance of the battery cell. Furthermore, when the folding plate 42 is fastened to the fixed plate 41, it can simultaneously fill the height difference between the two support portions 412 and the fitting portion 411, which is beneficial for improving assembly efficiency. The second venting structure 4231 on the folding plate 42 facilitates the venting of the explosion-proof valve 3.

[0040] In some embodiments of the present invention, in the thickness direction of the cover plate body 1, the projection of the exhaust hole is located within the projection distribution range of the first exhaust structure 41131, and the projection of the first exhaust structure 41131 is located within the projection distribution range of the second exhaust structure 4231.

[0041] It is understood that the second exhaust structure 4231, the first exhaust structure 41131, and the exhaust port are opposite each other in the thickness direction of the cover plate body 1. The area enclosed by the outer periphery of the first exhaust structure 41131 covers the area of ​​the exhaust port. The area enclosed by the outer periphery of the second exhaust structure 4231 covers the area of ​​the first exhaust structure 41131. In this way, the portion of the fixing plate 41 located outside the first exhaust structure 41131 can be avoided from obstructing the exhaust port, and the portion of the folding plate 42 located outside the second exhaust structure 4231 can be avoided from obstructing the first exhaust structure 41131, which is conducive to the smooth exhaust of the explosion-proof valve 3. Specifically, the first exhaust structure 41131 is disposed on the third bonding plate 4113 of the fixing plate 41, and the second exhaust structure 4231 is disposed on the third plate body 423 of the folding plate 42.

[0042] Optionally, multiple longitudinally and transversely arranged ribs can be provided inside the vent hole. These ribs can support the explosion-proof valve 3 and prevent deformation of the explosion-proof valve 3 during welding.

[0043] In this embodiment of the invention, both the first exhaust structure 41131 and the second exhaust structure 4231 can be a single through hole with a relatively large opening. Alternatively, both the first exhaust structure 41131 and the second exhaust structure 4231 can include multiple through holes with smaller openings, which can ensure the structural strength of the fixing plate 41 and the folding plate 42.

[0044] Specifically, the first exhaust structure 41131 includes a plurality of first through holes spaced apart from each other, and the second exhaust structure 4231 includes a plurality of second through holes spaced apart from each other. The area of ​​each exhaust hole is S1, and the area of ​​the exhaust hole, the plurality of first through holes, and the plurality of second through holes overlapping in the thickness direction of the cover plate body 1 is S4. Optionally, S4 / S1 ≥ 0.8. This overlapping area is the actual ventilation area; by setting S4 / S1 ≥ 0.8, it can be ensured that the explosion-proof valve 3 can exhaust smoothly.

[0045] like Figures 2-4 As shown, in some optional embodiments, the size of the vent hole is A1 along the length of the cover plate body 1, the size of the distribution area of ​​the first vent structure 41131 on the fixed plate 41 is A2, and the size of the distribution area of ​​the second vent structure 4231 on the folding plate 42 is A3, where 1.05 ≤ A2 / A1 ≤ 1.2 and 1.05 ≤ A3 / A2 ≤ 1.2. This is to prevent the portion of the fixed plate 41 outside the first vent structure 41131 along the length of the cover plate body 1 from obstructing the vent hole, and to prevent the portion of the folding plate 42 outside the second vent structure 4231 along the length of the cover plate body 1 from obstructing the first vent structure 41131; simultaneously, it avoids the distribution range of the first vent structure 41131 and the second vent structure 4231 along the length of the cover plate body 1 from being too large, thus affecting the structural strength of the fixed plate 41 and the folding plate 42.

[0046] In some optional embodiments, the size of the vent hole is B1 in the width direction of the cover plate body 1, the size of the distribution area of ​​the first vent structure 41131 on the fixed plate 41 is B2, and the size of the distribution area of ​​the second vent structure 4231 on the folding plate 42 is B3, where 1.05 ≤ B2 / B1 ≤ 1.2 and 1.05 ≤ B3 / B2 ≤ 1.2. This is to prevent the portion of the fixed plate 41 outside the first vent structure 41131 in the width direction of the cover plate body 1 from obstructing the vent hole, and to prevent the portion of the folding plate 42 outside the second vent structure 4231 in the width direction of the cover plate body 1 from obstructing the first vent structure 41131; it also prevents the distribution range of the first vent structure 41131 and the second vent structure 4231 in the width direction of the cover plate body 1 from being too large, thus affecting the structural strength of the fixed plate 41 and the folding plate 42.

[0047] In some optional embodiments, the area of ​​the exhaust port is S1, the distribution area of ​​the first exhaust structure 41131 on the fixed plate 41 is S2, and the distribution area of ​​the second exhaust structure 4231 on the folding plate 42 is S3, where 1.2 ≤ S3 / S2 ≤ 1.5 and 1.2 ≤ S2 / S1 ≤ 1.5. This ensures that the first exhaust structure 41131 and the second exhaust structure 4231 have sufficient flow area, while avoiding excessively large distribution areas that could affect the structural strength of the fixed plate 41 and the folding plate 42.

[0048] Where S1 is the area of ​​the region enclosed by the outer edge of the exhaust port, S2 is the area of ​​the region enclosed by the outer edge of the first exhaust structure 41131, and S3 is the area of ​​the region enclosed by the outer edge of the second exhaust structure 4231. For example, if the first exhaust structure 41131 includes a plurality of first through holes arranged in a matrix along the length and width directions of the cover plate body 1, then S2 = A2 × B2. If the second exhaust structure 4231 includes a plurality of second through holes arranged in a matrix along the length and width directions of the cover plate body 1, then S3 = A3 × B3.

[0049] like Figure 1 As shown, in this embodiment of the invention, the cover plate body 1 is provided with a boss 11 protruding away from the insulating member 4. The pole post 21 is spaced apart from the boss 11 along the length of the cover plate body 1. Optionally, along the length of the cover plate body 1, the pole post 21 is located between the support portion 412 and the boss 11.

[0050] The boss 11 is adapted to be connected to the battery pack housing for supporting the impact force transmitted from the housing. The part of the housing that is supported and connected to the boss 11 can be the housing shell; or, the housing includes a shell and a cold plate, with the cold plate located between the shell and the battery cells, and the boss 11 is supported and connected to the cold plate.

[0051] The boss 11 can be integrally formed on the cover plate body 1; or, the boss 11 can be welded and fixed to a substrate as an independent structural component to form the cover plate body 1. The boss 11 can be a solid structure; or, the boss 11 can be a hollow structure, that is, the side of the boss 11 facing the cavity forms a recess, which can reduce the weight of the battery cell.

[0052] When the boss 11 has an internally hollow structure, optionally, a through hole is provided on the substrate corresponding to the position of the boss 11, so that the side of the cover plate body 1 away from the boss 11 forms a recess that can accommodate the tab 51, which is beneficial to increasing the space utilization rate inside the cell housing, thereby increasing the capacity of the cell. Of course, if it is not necessary to accommodate the tab 51, the through hole on the substrate corresponding to the position of the boss 11 may not be provided, which is beneficial to improving the structural strength of the substrate at the position of the boss 11.

[0053] Optionally, the boss 11 is formed by stamping from a sheet metal. For example, the boss 11 is formed by stamping from a separate sheet metal and then welded to the substrate. Alternatively, the boss 11 is formed by stamping from the cover plate body 1 as a single piece, which allows the cover plate body 1 to form a recess to accommodate the tab 51 and simplifies the manufacturing process of the cover plate body 1.

[0054] In traditional battery pack structures, the battery pack relies solely on the casing to withstand external impacts. However, the casing plate opposite the terminal post 21 has a large area, and if its rigidity is insufficient, it is prone to deformation. To prevent casing deformation from causing compression damage to the busbar and terminal post 21, a large space needs to be reserved between the busbar and the casing in the structural design, and supporting foam needs to be installed between them. Some designs also incorporate concave and convex structures on the casing plate to enhance its rigidity and prevent deformation. However, these measures result in a large gap between the cell and the casing, wasting space. Increasing the casing thickness to increase rigidity would increase the weight of the battery pack, hindering lightweight design. Furthermore, the heat from the cell cover is dissipated only through conduction between the terminal post 21 and the busbar, and through its own thermal radiation, resulting in low heat dissipation efficiency and easy heat accumulation.

[0055] This invention, through the provision of a protrusion 11 on the cover plate body 1, utilizes the protrusion 11 for support and connection with the casing, allowing the outer shell of the battery cell itself to also serve as a supporting load-bearing component. This avoids significant deformation of the casing, facilitates a reduction in casing thickness, and enables a lightweight battery pack design. Furthermore, while ensuring the casing does not cause crush damage to the busbars and terminals 21, it reduces the distance between the busbars and the casing, thereby increasing the volume of the battery cell. This fully utilizes the internal space of the casing, improving the cell capacity and the overall energy density of the battery pack. The stepped protrusion 11 design helps to reduce the height of a single stamping while ensuring sufficient height for the protrusion 11, thus ensuring the structural strength of the protrusion 11. Simultaneously, the heat from the battery cell can be transferred to the casing through the protrusion 11, improving the heat dissipation efficiency of the battery cell.

[0056] It should be noted that the battery cell has two terminals 21, namely a positive terminal and a negative terminal. In this embodiment of the invention, the number of terminals 21 on the battery cell cover can be one or two. Figure 1 As shown, the cell cover plate is provided with two pole posts 21. In the length direction of the cell cover plate, the boss 11 is located between the two pole posts 21 to form better support and protection for the pole posts 21 on both sides.

[0057] In some embodiments of the present invention, the boss 11 includes a plurality of protrusions stacked sequentially along the thickness direction of the cover plate body 1.

[0058] It is understandable that, in the protruding direction of the boss 11, the cross-sectional area of ​​multiple protrusions decreases sequentially, forming a stepped boss 11. When the boss 11 is formed by stamping, the boss 11 can be formed by multiple stampings, reducing the height of a single stamping, avoiding sheet metal breakage, and ensuring the structural strength of the boss 11.

[0059] like Figure 1 As shown, taking a boss 11 with two protrusions as an example, the two protrusions are a first protrusion 111 and a second protrusion 112. The second protrusion 112 protrudes from the upper surface of the first protrusion 111, and the upper surface of the first protrusion 111 is connected to the battery pack housing support. The second protrusion 112 is located at the middle of the first protrusion 111 along the length of the cover plate body 1, which facilitates stamping and forming. Furthermore, the first protrusion 111 can be connected to the battery pack housing support through its portions located on both sides of the second protrusion 112, providing more stable support.

[0060] Optionally, both the first protrusion 111 and the second protrusion 112 include a top wall and a side wall connected to the top wall and inclined relative to the top wall. That is, both the first protrusion 111 and the second protrusion 112 are trapezoidal bosses 11, which is beneficial to improve the production yield of the stamping process. At the same time, when the space of the cover plate body 1 along its length direction is limited, the length of the sink 40 can be increased.

[0061] Optionally, the boss 11 is integrally bent from the cover plate body 1 along its length direction, that is, the recess formed on the second side of the cover plate body 1 extends through the opposite sides of the cover plate body 1 along its width direction. This boss 11 can be manufactured by a stamping process, and the bent shape of the boss 11 helps improve its processing stability. Specifically, the cover plate body 1 includes a base plate portion 12 and a bent portion. The bent portion is connected to the base plate portion 12 at both ends along the length direction of the cover plate body 1. The bent portion is bent relative to the base plate portion 12 to form the boss 11, and two pole posts 21 are correspondingly inserted into the two base plate portions 12.

[0062] In some embodiments of the present invention, the boss 11 can be supported and connected to the housing through its topmost protrusion.

[0063] In other embodiments of the invention, an exhaust port is provided in the topmost protrusion. At least one of the other protrusions is adapted to connect with the battery pack housing support.

[0064] It should be noted that the battery pack casing forms an accommodating space and is provided with a clearance hole connecting the inside and outside of the accommodating space. The topmost protrusion of the explosion-proof valve 3 passes through this clearance hole. When the internal pressure of the battery cell exceeds the safety threshold of the explosion-proof valve 3, the explosion-proof valve 3 opens, and the high-temperature and high-pressure gas inside the battery cell is discharged out of the accommodating space through the explosion-proof valve 3. Any one or more protrusions of the boss 11, except for the topmost protrusion, can be connected to the battery pack casing for support and to bear the impact force transmitted from the casing.

[0065] In traditional battery pack structures, when the terminal post 21 and the explosion-proof valve 3 are located at the same end of the battery cell, when the battery cell experiences thermal runaway, the substances discharged from the explosion-proof valve 3 can easily reach the terminal post 21, affecting the thermal insulation effect.

[0066] In this embodiment, the explosion-proof valve 3 is positioned on the topmost protrusion of the boss 11. This topmost protrusion can pass through a clearance hole on the battery pack casing, placing the explosion-proof valve 3 outside the housing space of the battery pack used to house the battery cells. At least one other protrusion is adapted to be connected to the casing support. The heat from the battery cells can be transferred to the casing through at least one protrusion, improving the heat dissipation efficiency of the battery cells. The explosion-proof valve 3 can be located outside the housing space, and the casing isolates the terminal post 21 and the explosion-proof valve 3, improving the thermoelectric isolation effect.

[0067] like Figure 2 and Figure 3 As shown, in this embodiment of the invention, a recess is formed on the side of the cover plate body 1 near the insulating member 4, corresponding to the position of the boss 11, and the fixing plate 41 engages with the recess. A groove 410 is formed on the side of the fixing plate 41 away from the cover plate body 1, corresponding to the position of the recess. When the folding plate 42 is fastened to the fixing plate 41, a recess 40 is formed on the side of the folding plate 42 away from the fixing plate 41, corresponding to the position of the groove 410.

[0068] Specifically, a protrusion is formed on the side of the fixing plate 41 near the cover plate body 1, and the protrusion is located in the recess of the cover plate body 1. A groove 410 is formed on the side of the fixing plate 41 away from the cover plate body 1 corresponding to the position of the protrusion. After the folding plate 42 is fastened to the fixing plate 41, a recess 40 is formed on the side of the insulating member 4 away from the cover plate body 1 corresponding to the position of the groove 410. The shape of the recess 40 can be a stepped groove adapted to the stepped boss 11. The electrode tabs 51 of the electrode group 5 can be retracted into the recess 40, making full use of the space inside the boss 11, so that there is more space inside the cell to set the body of the electrode group 5, improving the space utilization rate inside the cell and increasing the cell capacity.

[0069] Optionally, the shape of the protrusion of the insulating member 4 is adapted to the shape of the recess of the cover plate body 1 to maximize the use of the internal space of the protrusion 11. The folding plate 42 can be configured as a bent plate conformally to the fixing plate 41, so that when the folding plate 42 is fastened to the fixing plate 41, a groove 40 is formed on the side of the insulating member 4 away from the cover plate body 1.

[0070] like Figure 4 As shown, in some embodiments of the present invention, the cell cover further includes a connecting piece 22, which is located between the fixing plate 41 and the folding plate 42. The connecting piece 22 includes a base portion 221 and an extension portion 222. The base portion 221 is connected to the electrode post 21, and the extension portion 222 is located in the groove 410 for welding to the electrode tab 51 of the electrode group 5. When the folding plate 42 is fastened to the fixing plate 41, the folding plate 42 covers the base portion 221 and the extension portion 222.

[0071] Specifically, the connecting piece 22 extends from the pole post 21 into the groove 410 according to the shape of the fixing plate 41. The base portion 221 is located outside the groove 410, and the extension portion 222 is located inside the groove 410. The base portion 221 and the extension portion 222 are connected by an inclined portion.

[0072] When assembling the cell cover and the electrode assembly 5, first open the folding plate 42 and weld the electrode tab 51 of the electrode assembly 5 to the extension 222 located in the groove 410; then fasten the folding plate 42 to cover the entire connecting piece 22, and also cover the welded part of the electrode tab 51; finally, abut the end face of the electrode assembly 5 against the support part 412 of the cell cover and the folding plate 42. The folding plate 42 covers the welded part of the electrode tab 51 and serves to close and fix the electrode tab 51.

[0073] like Figure 4 As shown, the folding plate 42 has a first plate 421 and a second plate 422, with the first plate 421 folded and connected to the support portion 412. When the folding plate 42 is fastened to the fixing plate 41, the first plate 421 covers the base portion 221, and the second plate 422 is located in the groove 410 and covers the extension portion 222.

[0074] It is understandable that when the folding plate 42 is fastened to the fixing plate 41, the side of the first plate 421 away from the fixing plate 41 is flush with the support part 412, so that after the cell cover is assembled with the electrode group 5, the support part 412 and the first plate 421 simultaneously abut against the end face of the electrode group 5.

[0075] Specifically, such as Figure 5As shown, the fixing plate 41 has a first bonding plate 4111, a first connecting plate 4114, a second bonding plate 4112, a second connecting plate 4115, and a third bonding plate 4113 connected in sequence to form a stepped plate. A support portion 412 protrudes from the first bonding plate 4111, and a connecting piece 22 extends from the first bonding plate 4111 to the second bonding plate 4112. The first bonding plate 4111 is bonded to the substrate portion 12, the second bonding plate 4112 is bonded to the top wall of the first protrusion 111, the third bonding plate 4113 is bonded to the top wall of the second protrusion 112, the first connecting plate 4114 is opposite to the side wall of the first protrusion 111, and the second connecting plate 4115 is opposite to the side wall of the second protrusion 112. The two ends of the third bonding plate 4113 are symmetrical to each other and are connected in sequence to the second connecting plate 4115, the second bonding plate 4112, the first connecting plate 4114 and the first bonding plate 4111.

[0076] The folding plate 42 comprises a first plate 421, a third connecting plate 424, a second plate 422, a fourth connecting plate 426, and a third plate 423 connected in sequence to form a stepped plate. The first plate 421 is opposite to the first bonding plate 4111, the third connecting plate 424 is opposite to the first connecting plate 4114, the second plate 422 is opposite to the second bonding plate 4112, the fourth connecting plate 426 is opposite to the second bonding plate 4112, and the third plate 423 is opposite to the third bonding plate 4113. The two ends of the third plate 423 are symmetrically connected to each other and sequentially joined with the fourth connecting plate 426, the second plate 422, the third connecting plate 424, and the first plate 421. One of the first plates 421 is folded and connected to a support portion 412, and the other first plate 421 overlaps with another support portion 412.

[0077] Optionally, the first connecting plate 4114 is inclined relative to the second bonding plate 4112, and the second connecting plate 4115 is inclined relative to the third bonding plate 4113. Correspondingly, the third connecting plate 424 is inclined relative to the second plate body 422, the limiting plate 425 is inclined relative to the second plate body 422, and the fourth connecting plate 426 is inclined relative to the third plate body 423.

[0078] like Figure 6As shown, the angle between the third connecting plate 424 and the second plate 422 is 90°+β2, the angle between the fourth connecting plate 426 and the third plate 423 is 90°+γ2, the angle between the inclined portion of the connecting piece 22 connecting the base portion 221 and the extension portion 222 and the extension portion 222 is 90°+β1, and the angle between the first connecting plate 4114 and the second bonding plate 4112 is 90°+γ1. When the folding plate 42 is fastened to the fixing plate 41, in the length direction of the cover plate body 1, the length of the third bonding plate 4113 is L1, the length of the third plate 423 is L2, the distance between the ends of the extension portions 222 of the two connecting pieces 22 that are far apart from each other is L3, and the distance between the ends of the two second plates 422 located at both ends of the third plate 423 that are far apart from each other is L4.

[0079] To meet assembly requirements, β1=β2, γ1=γ2, 1.5mm≤(L1-L2) / 2≤3mm, and 1.5mm≤(L3-L4) / 2≤3mm. If (L1-L2) / 2 and (L3-L4) / 2 are too small, structural interference may easily occur between the folding plate 42 and the fixing plate 41; if (L1-L2) / 2 and (L3-L4) / 2 are too large, the dimension of the sink 40 in the length direction of the cover plate body 1 will be reduced, thus reducing the space within the sink 40.

[0080] like Figure 2 As shown, in some embodiments of the present invention, the width of the second plate 422 is smaller than the width of the first plate 421 in the width direction of the cover plate body 1. Since the welding part of the electrode lug 51 is pressed between the second plate 422 and the extension 222, the electrode lug 51 needs to be bent and folded within the groove 40. By setting the width of the second plate 422 to be smaller than the width of the first plate 421, space is provided to allow for the bending of the electrode lug 51, thus preventing the electrode lug 51 from being bent and damaged.

[0081] like Figure 4 As shown, in some embodiments of the present invention, the folding plate 42 and the fixing plate 41 are integrally formed, and a notch 43 extending along the folding line is formed between the side of the folding plate 42 near the fixing plate 41 and the support portion 412. Specifically, the notch 43 is formed between the first plate 421 of the folding plate 42 near the fixing plate 41 and the support portion 412.

[0082] Optionally, the folding plate 42 and the fixing plate 41 are integrally molded plastic parts. The notch 43 is formed between the folding connection end of the folding plate 42 and the support part 412, that is, the thickness of the folding plate 42 is reduced at the position corresponding to the notch 43, so as to facilitate the folding of the folding plate 42 and enable it to be well fastened to the fixing plate 41.

[0083] As a specific example, such as Figure 7As shown, when the folding plate 42 is fastened to the fixing plate 41, the width of the notch 43 is w1, the thickness of the portion of the folding plate 42 near the notch 43 is t1, and the thickness of the folding plate 42 corresponding to the position of the notch 43 is t2. t1 ≥ 1 mm, 0.4 ≤ t2 / t1 ≤ 0.6, and 0.2 mm ≤ w1 ≤ 0.5 mm. If the value of t2 / t1 is too small or the value of w1 is too large, the folding strength is insufficient, and the folding plate 42 is prone to breakage; if the value of t2 / t1 is too large or the value of w1 is too small, the folding plate 42 is difficult to fold and is prone to warping.

[0084] like Figure 1 As shown, in some embodiments of the present invention, the boss 11 is provided with reinforcing ribs 113, which extend from one protrusion to another. It is understood that a portion of the reinforcing rib 113 is connected to one protrusion and another portion is connected to another protrusion. The reinforcing rib 113 connects at least two adjacent protrusions to locally reinforce multiple protrusions and improve the overall impact resistance of the boss 11.

[0085] Optionally, the reinforcing rib 113 extends along the length of the cover plate body 1. The principal stress direction of the protrusion is consistent with the stacking direction of the multiple protrusions. The reinforcing rib 113 extends from one protrusion to another and along the length of the cover plate body 1, which helps to increase the structural strength of the protrusion and helps to disperse the stress of the protrusion.

[0086] The reinforcing rib 113 can protrude from the first side of the cover plate body 1, that is, on the same side of the cover plate body 1 as the boss 11, or it can protrude from the second side of the cover plate body 1. When the reinforcing rib 113 protrudes from the first side of the cover plate body 1, the reinforcing rib 113 and the boss 11 can be stamped together, simplifying the process.

[0087] like Figure 1 As shown, in one specific embodiment, the plurality of protrusions include a first protrusion 111 and a second protrusion 112. The second protrusion 112 protrudes from the upper surface of the first protrusion 111, and the upper surface of the first protrusion 111 is adapted to be connected to the housing support of the battery pack. A vent is provided on the second protrusion 112. A reinforcing rib 113 connecting the first protrusion 111 and the second protrusion 112 extends from the upper surface of the second protrusion 112 along the length direction to the upper surface of the first protrusion 111.

[0088] It is understood that the reinforcing rib 113 protrudes in the same direction as the boss 11, and the reinforcing rib 113 extends along the length of the cover plate body 1. The second protrusion 112 protrudes from the upper surface of the first protrusion 111, and a part of the reinforcing rib 113 is connected to the upper surface of the first protrusion 111, and another part is connected to the upper surface of the second protrusion 112.

[0089] Since the boss 11 is a structure that bends along the length of the cover plate body 1, it is prone to bending deformation when subjected to impact. The extension direction of the reinforcing rib 113 is consistent with the bending direction of the boss 11, which can improve the bending stiffness of the boss 11, thereby improving the overall structural strength of the boss 11.

[0090] In some embodiments of the present invention, such as Figure 2 As shown, the second protrusion 112 has a top wall and a first side wall and a second side wall disposed opposite to each other along the length of the cover body 1. Both the first and second side walls connect to the top wall and the first protrusion 111. The boss 11 is provided with a plurality of first reinforcing ribs and a plurality of second reinforcing ribs. The first reinforcing ribs extend along the length of the cover body 1 and sequentially connect the top wall, the first side wall, and the first protrusion. The second reinforcing ribs extend along the length and sequentially connect the top wall, the second side wall, and the first protrusion. The plurality of first reinforcing ribs are spaced apart along the width of the cover body 1, and the plurality of second reinforcing ribs are spaced apart along the width of the cover body 1. The plurality of first reinforcing ribs and the plurality of second reinforcing ribs are disposed opposite each other along the length of the cover body 1.

[0091] Understandably, the upper surface of the second protrusion 112 is formed in the top wall, and the vent hole penetrates the top wall. Multiple first reinforcing ribs and multiple second reinforcing ribs are spaced apart along the length, and the vent hole is located between the multiple first reinforcing ribs and multiple second reinforcing ribs. The first and second sides of the second protrusion 112 are its main stress areas. The first side is structurally reinforced by multiple first reinforcing ribs, and the second side is structurally reinforced by multiple second reinforcing ribs. This prevents the second protrusion 112 from deforming and experiencing increased structural stress when the protrusion 11 is impacted, thus avoiding abnormal cracking of the explosion-proof valve 3.

[0092] The multiple first reinforcing ribs and multiple second reinforcing ribs are arranged opposite each other in the length direction of the cover plate body 1, which can form an exhaust channel extending along the length direction of the cover plate body 1 on the upper surface of the second protrusion 112. The gas discharged by the explosion-proof valve 3 can flow along the exhaust channel, which is beneficial to improving the exhaust efficiency.

[0093] like Figure 1 As shown in the illustration, as a specific example, there are three of each of the first and second reinforcing ribs, forming two venting channels extending along the length of the cover plate body 1 on the second protrusion 112. When multiple battery cells are arranged along the width of the cover plate body 1, venting channels are also formed between the first and second reinforcing ribs of two adjacent battery cells.

[0094] It should be noted that the lengths of the multiple first reinforcing ribs and the multiple second reinforcing ribs can be unequal. The multiple first and multiple second reinforcing ribs can be arranged according to the shape of the vent hole. For example, the distance between each first and each second reinforcing rib and the edge of the vent hole can be equal, so that the first and second reinforcing ribs have relatively long lengths, thereby forming an effective venting channel.

[0095] like Figure 1 As shown, optionally, a plurality of first reinforcing ribs and a plurality of second reinforcing ribs are spaced apart along the length of the cover plate body 1.

[0096] It is understood that, along the length of the cover plate body 1, there is a certain distance between the multiple first reinforcing rib integral structures and the multiple second reinforcing rib integral structures, and the vent is located between them. When multiple battery cells are arranged along the width of the cover plate body 1, the vent channels on the second protrusions 112 of two adjacent battery cells can be interconnected in the width direction, which is beneficial to improving venting efficiency.

[0097] In this embodiment of the invention, the cover plate body 1 has a reference surface 121, which is a plane on the side of the cover plate body 1 where the boss 11 is provided, and can be formed on the base plate portion 12. The boss 11 and the pole post 21 both protrude from the reference surface 121. In the thickness direction of the cover plate body 1, the protrusion height of the pole post 21 relative to the reference surface 121 is less than the protrusion height of the first protrusion 111 relative to the reference surface 121, so that a certain space is reserved between the pole post 21 and the housing for the installation of the busbar.

[0098] Furthermore, in the structure of the battery module, the height of the busbar relative to the reference surface 121 is less than the protrusion height of the first protrusion 111 relative to the reference surface 121, so that there is a certain gap between the busbar and the housing. This gap can be used to maintain a safe distance between the busbar and the housing, and can also be used to install adhesive with thermal conductivity.

[0099] This invention also provides a battery cell, which includes a battery cell housing, an electrode assembly 5, and a battery cell cover plate as provided in any of the above embodiments. The battery cell housing has an opening, and the battery cell cover plate is disposed at the opening and surrounds the battery cell housing to form a receiving cavity. The electrode assembly 5 is disposed within the receiving cavity, and the welded portion of the electrode tab 51 of the electrode assembly 5 is located between the fixing plate 41 and the folding plate 42 and connected to the electrode post 21.

[0100] When assembling the battery cell, the electrode group 5 and the terminal post 21 of the battery cell cover are first welded together, and the battery cell cover is assembled to one end of the electrode group 5. Then, the electrode group 5 is installed into the battery cell housing, and the cover body 1 is welded to the battery cell housing. Before being installed into the housing, the outside of the electrode group 5 is usually wrapped with an insulating film to provide insulation between the electrode group 5 and the battery cell housing.

[0101] Furthermore, such as Figure 7As shown, in the thickness direction of the cover plate body 1, the welded part of the electrode lug 51 is located between the folding plate 42 and the connecting piece 22. The thickness of the welded part of the electrode lug 51 is t, and the distance between the second plate 422 of the folding plate 42 and the extension 222 of the connecting piece 22 is g2, where 0.2mm ≤ g2-t ≤ 0.5mm. If the value of g2-t is too small, the folding plate 42 is prone to damaging the electrode lug 51; if the value of g2-t is too large, the fixing effect of the folding plate 42 on the electrode lug 51 is not good.

[0102] Furthermore, when the folding plate 42 is fastened to the fixing plate 41, the distance between the first plate and the pole post 21 in the thickness direction of the cover plate body 1 is g1, where 0.2mm≤g1≤0.5mm. Where the folding plate 42 has a third plate 423, the distance between the third plate 423 and the fixing plate 41 is g3, where 0.2mm≤g3≤0.5mm.

[0103] like Figure 8 and Figure 9 As shown, in some embodiments of the present invention, the pole group 5 has two pole lugs 51 at the position corresponding to the second plate 422 of the folding plate 42. The two pole lugs 51 are arranged in the width direction of the cover plate body 1 and symmetrically distributed on both sides of the second plate 422. The dimension of the second plate 422 in the width direction of the cover plate body 1 is smaller than the distance between the two pole lugs 51 at their folded positions.

[0104] Specifically, the end of the extension 222 away from the base 221 is provided with two welding parts spaced apart along the width direction of the cover plate body 1. The two welding parts are welded to the two electrode tabs 51 of the electrode assembly 5 to reduce the impact of welding heat on the electrode tabs 51. The two electrode tabs 51 are respectively gathered from both sides of the folding plate 42 between the folding plate 42 and the extension 222, and are welded to the two welding parts of the extension 222 one by one. In order to avoid the folding plate 42 being too wide and interfering with the gathering of the electrode tabs 51, both sides of the folding plate 42 in the length direction are recessed by a certain width relative to the gathering position of the electrode tabs 51.

[0105] Among them, such as Figure 9 As shown, the distance between the folded positions of the two tabs 51 is G, the dimension of the second plate 422 in the width direction of the cover plate body 1 is W2, and the inward width of both sides of the folding plate 42 in the length direction relative to the folded positions of the tabs 51 is (G-W2) / 2. Optionally, 2mm ≤ (G-W2) / 2 ≤ 5mm. If (G-W2) / 2 is too small, the folded tabs 51 will interfere with the second plate 422; if (G-W2) / 2 is too large, the width of the second plate 422 will be too narrow, affecting its fixing effect on the tabs 51.

[0106] Specifically, such as Figure 10As shown, the electrode assembly 5 includes a first component and a second component that are independent of each other, each having an electrode tab 51. The extension 222 of the connecting piece 22 has two welding portions spaced apart in the width direction of the cover plate body 1. The electrode tab 51 of the first component is welded to one of the welding portions, and the electrode tab 51 of the second component is welded to the other welding portion. In this way, the welding heat of one electrode tab 51 and the welding portion can be avoided from affecting the welding of the other electrode tab 51, thereby improving the welding yield of the electrode tab 51.

[0107] like Figure 10 As shown, during welding, the first and second components can be placed on opposite sides of the cover plate body 1 along its length, with the tabs 51 of the first and second components facing each other. After welding the tabs 51 of both components to the pole post 21, the first and second components are flipped to their combined state, so that the ends of both components with tabs 51 are facing the cover plate body 1, thus completing the assembly of the pole group 5 and the cover plate body 1. See [link to documentation]. Figure 11 .

[0108] like Figure 8 As shown, in some embodiments of the present invention, the electrode assembly 5 has a connecting end face 50, on which a protrusion 52 is provided. An electrode tab 51 is connected to the connecting end face 50 and located beside the protrusion 52, which is housed within the recess 40 of the insulating member 4. In this way, the internal space of the battery cell can be fully utilized, increasing the volume of the electrode assembly 5 and thus increasing the battery cell capacity. The boss 11 formed by the bending portion of the cover plate body 1 can increase the internal space of the boss 11, increasing the volume of the protrusion 52, i.e., increasing the battery cell capacity.

[0109] It is understood that the electrode group 5 is formed by stacking multiple electrode sheets in the width direction of the cover plate body 1. Each electrode sheet has a protrusion at one end corresponding to the electrode tab 51, and the protrusions of multiple electrode sheets are stacked to form a protrusion 52.

[0110] Optionally, such as Figure 8 As shown, the surface of the protrusion 52 has a groove structure, which forms an exhaust channel inside the battery cell. The side of the protrusion 52 furthest from the connecting end face 50 is the upper surface of the protrusion 52, which is positioned opposite to the exhaust holes on the cover plate body 1 and the exhaust structure on the insulating component 4, allowing the groove structure on it to communicate with the exhaust holes and exhaust structure. When thermal runaway occurs in the battery cell, the high-temperature gas inside the cell can flow along the exhaust channel to the explosion-proof valve 3, improving the exhaust effect.

[0111] In some embodiments, the trench structure includes at least one first trench 521, which extends along the length of the connecting end face 50 and penetrates both sides of the protrusion 52. This facilitates the entry of gas from the inside of the battery cell, corresponding to the two sides in the width direction of the cover plate body 1, into the first trench 521.

[0112] In some embodiments, the trench structure includes at least one second trench 522, which extends along the width direction of the connecting end face 50 and penetrates the opposite sides of the protrusion 52. This facilitates the entry of gas inside the battery cell corresponding to the two sides of the cover plate body 1 along the length direction into the second trench 522.

[0113] In some embodiments, the trench structure includes at least one first trench 521 and at least one second trench 522. The first trench 521 extends along the length direction of the connecting end face 50 and penetrates the opposite sides of the protrusion 52, and the second trench 522 extends along the width direction of the connecting end face 50 and penetrates the opposite sides of the protrusion 52. This facilitates the entry of gas from the periphery of the battery cell into the trench structure, improving exhaust efficiency.

[0114] like Figure 8 As shown, in some embodiments of the present invention, the convex bulge 52 has a top surface 5201 and a side surface 5202. The two ends of the top surface 5201 in the length direction of the cover plate body 1 are respectively connected to the connecting end surface 50 through a side surface 5202 to form a trapezoidal convex bulge 52. The first groove 521 extends from one end of the side surface 5202 away from the top surface 5201 to the other end of the side surface 5202 away from the top surface 5201.

[0115] It is understood that the side surface 5202 is inclined relative to the connecting end face 50, and the side surface 5202 and the connecting end face 50 are set at an obtuse angle. The first groove 521 extends from one end of the side surface 5202 connected to the connecting end face 50 to the other end of the side surface 5202 connected to the connecting end face 50, so that the airflow flowing along the connecting end face 50 can smoothly enter the first groove 521.

[0116] like Figure 2 As shown, in some embodiments of the present invention, the groove 410 includes a first groove portion 401 and a second groove portion 402. The first groove portion 401 is formed on the side of the insulating member 4 facing the electrode group 5, corresponding to the position of the first protrusion 111. The second groove portion 402 is recessed in the first groove portion 401 and is disposed opposite to the second protrusion 112. The protrusion 52 extends into the second groove portion 402 and is positioned and engaged with the second groove portion 402 in the length direction of the cover plate body 1.

[0117] It is understood that the groove 40 is a stepped groove composed of a first groove 401 and a second groove 402. The deeper second groove 402 is used to limit the engagement with the protrusion 52 of the electrode assembly 5, which can play an assembly and positioning role during the assembly of the cell cover and the electrode assembly 5, and can prevent the electrode assembly 5 from moving and damaging the electrode tab 51 along the length direction of the cover body 1 when the cell is subjected to external force impact. The space formed between the connecting end face 50 of the electrode assembly 5 and the first groove 401 can be used to accommodate the electrode tab 51.

[0118] Define the length dimension L of the cover plate body and the width dimension W of the cover plate body. Based on the parameter value ranges defined in this embodiment of the invention, a Design of Experiments (DOE) is conducted using cover plate bodies with dimensions of 150mm≤L≤300mm and 25mm≤W≤75mm as the subjects.

[0119] Experiment 1: Five battery cells were randomly selected from each case for safety testing. The following observations were made: whether the explosion-proof valve opened normally, whether the explosion-proof valve released gas smoothly, and whether the battery cell casing cracked. The experimental results are shown in Tables 1 and 2. The units for A1, B2, A2, B2, A3, and B3 in the tables are mm, and the units for S1, S2, S3, and S4 are mm. 2 .

[0120] Table 1: Experimental Data 1 Table 2: Experimental Data 2

[0121] Table 2 shows the experimental results. When the cover plate body meets the design requirements of the above embodiments, as shown in Cases 1-9 in Tables 1 and 2, the pass rate of the cell safety test is high, and the cell safety is high. Conversely, as shown in Cases 10-12 in Tables 1 and 2, the cell venting is not smooth, the casing cracks, and the cell is prone to thermal runaway.

[0122] Experiment 2: Folding tests were conducted on the folding plates of multiple cell cover plates to determine whether the strength at the notch met the usage requirements. After assembling the cell cover plates with the electrode assembly, X-ray inspection was used to check the fixing effect of the insulation components on the electrode tabs, whether the folding plates damaged the electrode tabs, the distance between the two sides of the folding plates and the electrode tabs, and the fit clearance between the folding plates and the fixing plates. The experimental results are shown in Tables 3 and 4. The units of t1, t2, w1, g2, G, W2, t, L1, L2, L3, and L4 in the tables are mm.

[0123] Table 3: Experimental Data Table 4: Experimental Data

[0124] Table 4 shows the experimental results. When the cover plate body meets the design requirements of the above embodiments, referring to cases 1-9 in Tables 3 and 4, the strength at the notch of the insulating component is sufficient, the electrode lugs are well fixed and there is no electrode lug damage, and there is no interference problem when assembling the insulating component with the electrode group. Conversely, referring to cases 10-12 in Tables 3 and 4, the strength at the notch of the folding plate is insufficient and it is easy to break; or after assembly with the electrode group, there is a risk of damage to the electrode lugs or interference, reducing safety.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery cell cover plate, characterized in that, include: The cover plate body is equipped with vent holes; An explosion-proof valve is installed on the cover plate body and is opposite to the vent hole; An insulating component includes a fixed plate and a folding plate. The fixed plate is located on one side of the cover plate body and has two support portions protruding away from the cover plate body. The two support portions are spaced apart along the length of the cover plate body. One end of the folding plate is folded and connected to one of the support portions, so that the folding plate can be fastened or opened relative to the fixed plate. The fixed plate is provided with a first venting structure, and the folding plate is provided with a second venting structure. The pole is inserted through the cover plate body and the fixing plate along the thickness direction of the cover plate body, and the pole and the explosion-proof valve are located between the two support parts in the length direction; When the folding plate is fastened to the fixing plate, the vent hole, the first vent structure and the second vent structure are connected, the folding plate covers the pole post and its other end is connected to another support part, and both the support part and the folding plate are adapted to abut against the pole group of the battery cell.

2. The cell cover plate according to claim 1, characterized in that, In the thickness direction, the projection of the exhaust hole is located within the projection distribution range of the first exhaust structure, and the projection of the first exhaust structure is located within the projection distribution range of the second exhaust structure.

3. The cell cover plate according to claim 2, characterized in that, The first exhaust structure includes a plurality of first through holes spaced apart from each other, and the second exhaust structure includes a plurality of second through holes spaced apart from each other. The area of ​​the exhaust holes is S1, and the area of ​​the exhaust holes, the plurality of first through holes and the plurality of second through holes overlapping in the thickness direction is S4, where S4 / S1≥0.

8.

4. The cell cover plate according to claim 2, characterized in that, Along the length of the cover plate body, the size of the vent hole is A1, the size of the distribution area of ​​the first vent structure on the fixed plate is A2, the size of the distribution area of ​​the second vent structure on the folding plate is A3, 1.05≤A2 / A1≤1.2, 1.05≤A3 / A2≤1.2; And / or, in the width direction of the cover plate body, the size of the vent hole is B1, the size of the distribution area of ​​the first vent structure on the fixed plate is B2, the size of the distribution area of ​​the second vent structure on the folding plate is B3, 1.05≤B2 / B1≤1.2, 1.05≤B3 / B2≤1.2; And / or, the area of ​​the exhaust hole is S1, the area of ​​the distribution area of ​​the first exhaust structure on the fixed plate is S2, the area of ​​the distribution area of ​​the second exhaust structure on the folding plate is S3, 1.2≤S3 / S2≤1.5, 1.2≤S2 / S1≤1.

5.

5. The cell cover plate according to claim 1, characterized in that, The cover plate body has a boss protruding to the side away from the insulating member, and the pole post is spaced apart from the boss in the length direction.

6. The cell cover plate according to claim 5, characterized in that, The boss includes a plurality of protrusions stacked sequentially along the thickness direction of the cover plate body, and the vent hole is disposed in the topmost protrusion.

7. The cell cover plate according to claim 5, characterized in that, The cover plate body includes a base plate portion and a bent portion. The two ends of the bent portion are respectively connected to the base plate portion in the length direction. The bent portion is bent relative to the base plate portion to form the boss. The two pole posts are correspondingly inserted into the two base plate portions.

8. The cell cover plate according to claim 5, characterized in that, The cover plate body has a recess on the side near the insulating member corresponding to the protrusion, the fixing plate cooperates with the recess, and the fixing plate has a groove on the side away from the cover plate body corresponding to the recess; when the folding plate is fastened to the fixing plate, the side of the folding plate away from the fixing plate has a recessed groove on the side corresponding to the groove.

9. The cell cover plate according to claim 8, characterized in that, Also includes: A connecting piece is located between the fixed plate and the folding plate. The connecting piece includes a connected base portion and an extension portion. The base portion is connected to the pole post, and the extension portion is located in the groove for welding to the pole lug of the pole assembly. When the folding plate is fastened to the fixed plate, the folding plate covers the base portion and the extension portion.

10. A battery cell, characterized in that, include: The battery cell casing has an opening; The cell cover plate as described in any one of claims 1 to 7, wherein the cell cover plate is disposed at the opening and surrounds the cell housing to form a receiving cavity; An electrode assembly is disposed within the receiving cavity, and the welding portion of the electrode lug of the electrode assembly is located between the fixing plate and the folding plate and is welded to the electrode post.

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