Battery cell cover plate, battery cell and battery module

Abstract

The present invention relates to the technical field of batteries, and provides a battery cell cover plate, a battery cell and a battery module, the battery cell cover plate comprises: a cover plate body, the cover plate body comprises a substrate and at least one boss, the substrate is provided with a plurality of through holes spaced from the boss, the boss is connected to the plate surface of the substrate and is convexly arranged on the plate surface along the thickness direction, one side of the boss away from the plate surface is provided with a supporting surface; a groove is formed in the side, away from the boss, of the cover plate body and corresponds to the boss. The pole penetrates through one through hole and is convexly arranged on the plate surface; wherein the projected area of the battery cell cover plate in the thickness direction is S, the total area of the plurality of through holes is S0, and S0 / S is greater than or equal to 0.07 and less than or equal to 0.15. According to the battery cell cover plate, the space utilization rate in the battery pack box body is improved, and the capacity of the whole battery pack and the capacity of single battery cells in the battery pack are increased.

Description

Technical Field

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

[0002] The battery pack includes a casing and battery modules assembled inside the casing. Each battery module consists of multiple cells, with the terminals of these cells electrically connected via busbars. The casing provides physical support for the battery modules, protecting them from external impacts and pressure, while also preventing the intrusion of moisture, dust, and other impurities. As users' demands for longer battery life continue to increase, current battery technology faces a contradiction: battery capacity development lags behind market demand, leading to user range anxiety.

[0003] In traditional battery pack structures, to prevent the busbars and terminals from being squeezed when the casing deforms under external impact, a large space is left between the busbars and the battery pack casing. However, this requires reducing the volume of individual cells, resulting in lower capacity for individual cells and the overall battery pack. Summary of the Invention

[0004] This invention provides a cell cover, a cell, and a battery module to solve the problem of low overall capacity of existing battery packs and their individual cells.

[0005] This invention provides a battery cell cover plate, comprising: The cover plate body includes a base plate and at least one boss. The base plate has a plurality of through holes spaced apart from the boss. The boss is connected to the surface of the base plate and protrudes from the surface of the base plate along the thickness direction. The side of the boss away from the surface of the base plate has a support surface. The side of the cover plate body away from the boss forms a groove corresponding to the position of the boss. The pole post is inserted through one of the through holes and protrudes from the plate surface; Wherein, the projected area of ​​the cell cover plate in the thickness direction is S, the total area of ​​the plurality of through holes is S0, and 0.07≤S0 / S≤0.15.

[0006] According to the present invention, a battery cell cover plate is provided, wherein the boss and the substrate are integrally stamped, the wall thickness of the top wall of the boss is T2, 1.5mm≤T2≤2mm; the area of ​​the supporting surface of a single boss is S5', the yield strength of the substrate is R, and the force on the boss along the thickness direction is F, 1.3F / 2S5'<R; wherein, the unit of S5' is mm. 2 The unit of R is MPa, and the unit of F is N.

[0007] According to the present invention, the boss and the substrate are integrally stamped, the thickness of the substrate is T1, the protrusion height of the boss relative to the board surface is H2, 1.5mm≤T1≤3mm, and H2 / T1≤3.

[0008] According to a battery cell cover plate provided by the present invention, the boss further has a peripheral side surface, the peripheral side surface is connected between the support surface and the substrate, the peripheral side surface is a conical surface, and the cross-section of the conical surface gradually decreases in the direction away from the substrate.

[0009] According to the present invention, the taper of the conical surface is β, where 15°≤β≤25°.

[0010] According to a battery cell cover plate provided by the present invention, the protrusion height of the electrode post relative to the plate surface is H1, and the protrusion height of the boss relative to the plate surface is H2, where 1.5mm≤H2-H1≤3.0mm.

[0011] According to the present invention, a battery cell cover plate is provided, wherein the cover plate body is a manganese-aluminum alloy plate, wherein the aluminum content is ≥98% and the manganese content is ≥1%; The boss and the substrate are integrally stamped. The substrate has a tensile strength of σ, a yield strength of R, an elongation of δ, and an elastic modulus of E; wherein, 145 MPa ≤ σ ≤ 195 MPa, R ≥ 125 MPa, δ ≥ 3%, and 68 GPa ≤ E ≤ 70 GPa.

[0012] A cell cover plate provided by the present invention further includes: An explosion-proof valve is disposed in another through hole. The pole, the explosion-proof valve and the boss are arranged at intervals along the length of the substrate, and the boss is provided between the pole and the explosion-proof valve.

[0013] The present invention also provides a battery cell, comprising: a battery cell housing, an electrode assembly, and any one of the above-mentioned battery cell cover plates; the battery cell housing has an opening, the battery cell cover plate is disposed in the opening and surrounds the battery cell housing to form a receiving cavity, the electrode assembly is disposed in the receiving cavity, and the electrode tabs of the electrode assembly are connected to the electrode posts.

[0014] The present invention also provides a battery module, comprising: a busbar and a plurality of cells as described above, wherein the end of the terminal post away from the terminal group is connected to the busbar; in the thickness direction, the height of the side of the busbar away from the terminal post relative to the plate surface is less than the height of the boss relative to the plate surface.

[0015] The present invention provides a cell cover plate, a cell, and a battery module. By providing protrusions on the outer surface of the cover plate body, the cells, after being assembled into the housing, can be supported and connected to the housing plate using the protrusions. That is, the cell's outer shell acts as a supporting load-bearing component, preventing deformation of the housing plate under impact. This allows for an increase in cell volume while ensuring the housing does not cause crush damage to the busbars and terminals, thus fully utilizing the space within the housing and increasing the capacity of individual cells and the entire battery pack. It also reduces the thickness of the housing plate, facilitating lightweight battery pack design. Simultaneously, by setting 0.07≤S0 / S≤0.15, the structural strength of the substrate is considered, improving the impact resistance of the cell shell. 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 one of the structural schematic diagrams of the battery cell cover plate provided by the present invention.

[0018] Figure 2 This is a top view of the battery cell cover plate provided by the present invention.

[0019] Figure 3 This is a partial side view of the battery cell cover plate provided by the present invention.

[0020] Figure 4 yes Figure 2 Partial sectional view of the cell cover plate at point II.

[0021] Figure 5 This is the second schematic diagram of the structure of the battery cell cover plate provided by the present invention.

[0022] Figure 6 This is one of the structural schematic diagrams of the battery cell provided by the present invention.

[0023] Figure 7 This is a schematic diagram of the assembly structure of the battery cell cover plate and the electrode assembly covered with an insulating film provided by the present invention.

[0024] Figure 8 yes Figure 7 A partial cross-sectional view of the assembled structure.

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

[0026] Figure 10This is a schematic diagram of the structure of the insulating film provided by the present invention.

[0027] Figure 11 This is a schematic diagram of the assembly of the insulating film and the electrode tabs of the electrode assembly provided by the present invention.

[0028] Figure 12 This is one of the schematic diagrams of the insulating film provided by the present invention wrapped around the outside of the electrode assembly.

[0029] Figure 13 This is the second schematic diagram of the insulating film provided by the present invention wrapped around the outside of the electrode assembly.

[0030] Figure 14 This is a schematic diagram of the structure of the protective patch provided by the present invention.

[0031] Figure 15 This is a schematic diagram of the assembly structure of the battery cell cover and busbar provided by the present invention.

[0032] Figure 16 This is a partial structural diagram of a battery cell with a protective patch provided by the present invention.

[0033] Figure 17 This is the second schematic diagram of the battery cell provided by the present invention.

[0034] Figure label: 100. Cell cover plate; 11. Cover plate body; 111. Substrate; 112. Boss; 1121. Support surface; 1122. Peripheral side surface; 1123. Injection hole; 12. Terminal post; 13. Groove; 14. Explosion-proof valve; 15. Insulating component; 151. Protrusion; 152. Sink; 1521. First sink wall; 1522. Second sink wall; 16. Protective patch; 161. Substrate; 1611. Through hole; 1612. Opening; 162. Protective structure; 1621. Enclosure part; 1622. Covering part; 1623. Clearance notch; 16231. First notch; 16232. Second notch; 17. Connecting piece; 171. First contact part; 172. Second contact part; 173. Connecting part; 200. Cell housing; 300. Electrode assembly; 31. First side surface; 32. Second side surface; 33. First end face; 34. Electrode tab; 400. Insulating film; 41. First membrane assembly; 411. First membrane body; 4111. First wrapping part; 4112. Second wrapping part; 412. Second membrane body; 4121. Clearance hole; 4122. Vent hole; 413. Third membrane body; 4131. Third wrapping part; 4132. Fourth wrapping part; 42. Second membrane assembly; 421. First fold body; 422. Second fold body; 423. Third fold body; 500. Busbar; X. Length direction of substrate; Y. Width direction of substrate; Z. Thickness direction of substrate. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] The following is combined Figures 1-17 The present invention describes a cell cover plate, a cell, and a battery module.

[0038] like Figure 1 As shown, the battery cell cover 100 provided in this embodiment of the invention includes a cover body 11 and a terminal post 12. The cover body 11 includes a substrate 111 and at least one boss 112. The substrate 111 has a plurality of through holes spaced apart from the boss 112. The boss 112 is connected to the surface of the substrate 111 and protrudes from the surface along the thickness direction. The side of the boss 112 away from the surface has a support surface 1121. A groove 13 is formed on the side of the cover body 11 away from the boss 112, corresponding to the position of the boss 112. The terminal post 12 passes through a through hole and protrudes from the surface of the substrate 111. The projected area of ​​the battery cell cover 100 in the thickness direction of the substrate 111 is S, and the total area of ​​the plurality of through holes spaced apart from the boss 112 on the substrate 111 is S0, where 0.07 ≤ S0 / S ≤ 0.15. It can be understood that the protrusion direction of the boss 112 and the terminal post 12 is consistent with the thickness direction of the substrate 111.

[0039] The cell cover 100 is applied to the cell, which includes a cell housing 200, an electrode assembly 300, and the cell cover 100. The cell housing 200 has an opening, and the cell cover 100 is disposed at the opening and surrounds the cell housing 200 to form a receiving cavity. The electrode assembly 300 is disposed within the receiving cavity. The cell housing 200 and the cover body 11 constitute the outer shell of the cell, providing protection for the internal components and enabling it to withstand certain external impacts. The electrode post 12 protrudes from the surface of the substrate 111, forming a terminal for connection to the busbar. The other end is located within the receiving cavity and connected to the tab 34 of the electrode assembly 300.

[0040] See the length and width directions of substrate 111. Figure 1 The substrate 111 includes a first plate surface and a second plate surface opposite to each other in its thickness direction. The first plate surface faces the outside of the battery cell, and the second plate surface faces the electrode assembly 300 inside the receiving cavity. A boss 112 protrudes from the first plate surface, and the supporting surface 1121 of the boss 112 is used for supporting connection with the battery pack housing. The portion of the housing that is supported and connected to the boss 112 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 cell, and the boss 112 supported and connected to the cold plate.

[0041] Optionally, the protrusion height of the pole post 12 relative to the first plate surface is less than the protrusion height of the boss 112 relative to the first plate surface, so that a certain space is reserved between the pole post 12 and the housing for the installation of the busbar.

[0042] In traditional battery pack structures, the battery pack relies solely on the casing to withstand external impacts. The casing plate opposite the terminal post 12 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 12, 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 cells and the casing, wasting space. Increasing the casing thickness to increase rigidity would increase the weight of the battery pack, hindering lightweight design.

[0043] To address this, this embodiment provides a boss 112 on the outer surface of the cell cover 100. The boss 112 is used to support and connect with the casing, allowing the outer shell of the cell itself to also serve as a supporting component. Under the support of the outer shell, significant deformation of the casing can be avoided, thereby reducing the thickness of the casing and the weight of the battery pack. Furthermore, while ensuring that the casing does not cause crush damage to the busbars and terminals 12, the distance between the busbars and the casing can be reduced, thereby increasing the volume of the cell. This fully utilizes the internal space of the casing, increasing the cell capacity and the energy density of the entire battery pack.

[0044] It is understandable that the boss 112 has an internal hollow structure, and the side of the boss 112 facing the substrate 111 is set as a recess, so that the side of the cover plate body 11 away from the boss 112 forms a groove 13 corresponding to the position of the boss 112. This not only reduces the weight of the cover plate body 11 to reduce the weight of the cell and battery pack, but the groove 13 can also be used to accommodate the tabs 34 of the electrode assembly 300, which is beneficial to increasing the space utilization rate within the cell housing 200, thereby increasing the capacity of the cell.

[0045] The boss 112 and the substrate 111 can be integrally formed, or the boss 112 can be welded to the substrate 111 as an independent structural component. Optionally, the boss 112 can be formed by stamping from a sheet metal. For example, the boss 112 can be stamped from a separate sheet metal and then welded to the substrate 111. Alternatively, the boss 112 and the substrate 111 can be integrally stamped, which simplifies the manufacturing process of the cover plate body 11.

[0046] It should be noted that the battery cell has two terminals 12, namely a positive terminal 12 and a negative terminal 12. In this embodiment of the invention, the number of terminals 12 on the battery cell cover plate 100 can be one or two. The number of protrusions 112 can be one or more, specifically determined according to the size of the substrate 111 and the volume and load-bearing capacity of the protrusions 112. When there are multiple protrusions 112, the substrate 111 is provided with multiple protrusions 112 arranged along its length direction; and / or, the substrate 111 is provided with multiple protrusions 112 arranged along its width direction. The sizes of the multiple protrusions 112 can be the same or different.

[0047] Optionally, the cell cover 100 further includes an explosion-proof valve 14, which is disposed on the substrate 111 with a through hole spaced apart from the boss 112. Specifically, the substrate 111 has a first through hole and a second through hole spaced apart from the boss 112. The electrode post 12 passes through the first through hole, and the explosion-proof valve 14 is disposed in the second through hole. The number of first through holes is the same as the number of electrode posts 12, and the number of second through holes is one. It should be noted that if the cell cover 100 does not include the explosion-proof valve 14, the second through hole is not provided. The cover body 11 may also be provided with a liquid injection hole 1123, which may be disposed on the boss 112 or disposed on the substrate 111 with a spaced-apartment from the boss 112. If the liquid injection hole 1123 is disposed on the substrate 111, the liquid injection hole 1123 is a third through hole spaced apart from the boss 112.

[0048] The projected area S of the cell cover 100 in the thickness direction of the substrate 111 is equivalent to the projected area of ​​the area enclosed by the outer periphery of the substrate 111 in the thickness direction. The total area of ​​all through holes spaced apart from the bosses 112 on the substrate 111 is S0, where 0.07 ≤ S0 / S ≤ 0.15. If the value of S0 / S is too large, it indicates that the opening area on the substrate 111 is too large, which affects the structural strength of the substrate 111; if the value of S0 / S is too small, it affects the assembly of the substrate 111 with the pole post 12 and the explosion-proof valve 14.

[0049] For example, see Figure 1 The cover plate body 11 has two bosses 112 and two pole posts 12. The area of ​​the first through hole corresponding to each pole post 12 is equal and is S1. The area of ​​the second through hole corresponding to the explosion-proof valve 14 is S2. The area of ​​the injection hole 1123, which is a third through hole spaced apart from the bosses 112, is S3. When the substrate 111 has only two first through holes, the total area of ​​all through holes is S0 = 2S1. When the substrate 111 has only two first through holes and one second through hole, the total area of ​​all through holes is S0 = 2S1 + S2. When the substrate 111 has only two first through holes, one second through hole, and one third through hole, the total area of ​​all through holes is S0 = 2S1 + S2 + S3.

[0050] The cell cover 100 provided in this embodiment of the invention, by providing a protrusion 112 on the outer surface of the cover body 11, allows the cell to be assembled into the housing and supported by the protrusion 112 and the housing plate. That is, the cell's outer shell acts as a supporting load-bearing component, preventing deformation of the housing plate under impact. This increases the cell volume while ensuring the housing does not cause crush damage to the busbars and terminals 12, thus fully utilizing the space within the housing and increasing the capacity of a single cell and the entire battery pack. It also reduces the thickness of the housing plate, facilitating lightweight battery pack design. Simultaneously, by setting 0.07≤S0 / S≤0.15, the structural strength of the substrate 111 is considered, improving the impact resistance of the cell shell.

[0051] like Figure 4 As shown, the wall thickness of the boss 112 is defined as T2, the area of ​​the supporting surface 1121 of a single boss 112 is defined as S5', the yield strength of the substrate 111 is R, and the force exerted on the boss 112 along the thickness direction of the substrate 111 is F. In some embodiments of the present invention, the boss 112 and the substrate 111 are integrally stamped, with 1.5mm ≤ T2 ≤ 2mm and 1.3F / 2S5' < R. Wherein, the unit of S5' is mm. 2R is in MPa and F is in N. When the battery pack is subjected to an impact along the thickness direction of the substrate 111, the force acting on a single boss 112 is defined as F, and the stress on the boss 112 is F / S5'. By setting 1.3F / 2S5' < R, it can be ensured that the single boss 112 meets the structural strength requirements under this impact environment.

[0052] In some embodiments of the present invention, the boss 112 and the substrate 111 are integrally stamped. The thickness of the substrate 111 is T1, and the protrusion height of the boss 112 relative to the substrate 111 is H2, where 1.5mm ≤ T1 ≤ 3mm, and H2 / T1 ≤ 3. If T1 is too small, it will affect the structural strength of the boss 112; if T1 is too large, it will increase the weight and volume of the cell cover 100. If H2 / T1 is too large, the wall thickness of the stamped boss 112 is difficult to guarantee, affecting the structural strength of the boss 112.

[0053] For square batteries, such as blade batteries, the substrate 111 of the cell cover 100 is rectangular, and the corresponding boss 112 can also be set as rectangular. That is, the cross-section of the boss 112 in its protruding direction is rectangular, the long side of the boss 112 extends along the length direction of the substrate 111, and the wide side of the boss 112 extends along the width direction of the substrate 111, which is beneficial to make full use of the space in the length and width directions of the substrate 111. Of course, the shape of the boss 112 is not limited to rectangle; for example, it can also be circular or elliptical.

[0054] like Figure 1 and Figure 3 As shown, in some embodiments of the present invention, the boss 112 is a conical boss 112. Specifically, the boss 112 also has a peripheral side surface 1122, which is connected between the support surface 1121 and the substrate 111. The peripheral side surface 1122 is a conical surface, and the cross-section of the conical surface gradually decreases in the direction away from the substrate 111. The conical surface design of the conical boss 112 can distribute the load along the conical surface, resulting in a more uniform stress distribution. Furthermore, the conical structure can increase the shear and bending resistance of the boss 112, which is beneficial to improving the load-bearing capacity of the boss 112. In addition, when a groove 13 is formed on the side of the cover plate body 11 away from the boss 112, the conical boss 112 can increase the accommodating space of the tab 34.

[0055] Optionally, such as Figure 3 As shown, the taper of the conical surface is β, where 15°≤β≤25°. This taper range is beneficial for ensuring machinability, the structural strength of the boss 112, and the uniformity of stress distribution, thereby improving production yield. If the taper is too small, it is not conducive to the stamping process and can easily cause uneven stress distribution; if the taper is too large, the boss 112 will occupy too much area, which is not conducive to the distribution of the pole post 12, the boss 112, and the explosion-proof valve 14.

[0056] In some embodiments of the present invention, the boss 112 has multiple layers of protrusions 151 stacked in its protruding direction. The multiple layers of protrusions 151 can be formed by multiple stampings, which can reduce the height of a single stamping, avoid plate breakage, and ensure the structural strength of the boss 112.

[0057] like Figure 3 As shown, in some embodiments of the present invention, the protrusion height of the terminal post 12 relative to the surface of the substrate 111 is H1, and the protrusion height of the boss 112 relative to the surface of the substrate 111 is H2, where 1.5mm ≤ H2 - H1 ≤ 3.0mm. That is, the height of the boss 112 relative to the substrate 111 is higher than the height of the terminal post 12 relative to the substrate 111. This ensures that when the boss 112 is connected to the housing, there is still a certain space between the terminal post 12 and the housing for the busbar, and that the protrusion height of the boss 112 relative to the substrate 111 is slightly higher than the height of the busbar relative to the substrate 111. This helps to ensure that the housing does not cause crush damage to the busbar and the terminal post 12. If H2 - H1 is too small, the risk of the housing causing crush damage to the busbar and the electrode assembly 300 increases; if H2 - H1 is too large, the boss 112 will be too high, resulting in wasted space and hindering the improvement of battery capacity.

[0058] In some embodiments of the present invention, the cover plate body 11 is a manganese-aluminum alloy plate, wherein the aluminum content is ≥98% and the manganese content is ≥1%. The boss 112 and the base plate 111 are integrally stamped. The tensile strength of the base plate 111 is σ, the yield strength is R, the elongation is δ, and the elastic modulus is E; wherein, 145≤σ≤195MPa, R≥125MPa, δ≥3%, and 68Gpa≤E≤70Gpa. This manganese-aluminum alloy plate, while meeting the design strength of the boss 112, has good weldability, formability, and corrosion resistance, while also taking into account the dimensional accuracy of the boss 112.

[0059] like Figure 2 As shown, in some embodiments of the present invention, the distance between the boss 112 and the electrode post 12 along the length of the substrate 111 is L1, where 5mm ≤ L1 ≤ 10mm. The substrate 111 and the boss 112 are typically made of a conductive metal material. If L1 is too small, the risk of creepage short circuit increases after the battery cell is energized; if L1 is too large, it will reduce the size of the boss 112 along the length of the substrate 111, which is not conducive to improving the support strength of the boss 112.

[0060] The battery cell cover 100 provided in this embodiment of the invention also includes an explosion-proof valve 14, which is disposed in a through hole on the substrate 111. The electrode post 12, the explosion-proof valve 14 and the boss 112 are arranged at intervals along the length direction of the substrate 111, and the boss 112 is provided between the electrode post 12 and the explosion-proof valve 14.

[0061] As described in the above embodiment, the explosion-proof valve 14 is disposed in the second through hole of the substrate 111. When the internal pressure of the battery cell exceeds the safety threshold of the explosion-proof valve 14, the explosion-proof valve 14 opens, and the high-temperature and high-pressure gas in the containment cavity is discharged through the explosion-proof valve 14, reducing the internal pressure of the battery cell and preventing the battery cell from exploding.

[0062] A boss 112 is provided between the terminal post 12 and the explosion-proof valve 14. The boss 112 can be used to block the high-temperature gas or liquid ejected from the explosion-proof valve 14 from reaching the terminal post 12 and the busbar, thereby achieving thermoelectric isolation and improving the safety performance of the battery pack. The height of the explosion-proof valve 14 relative to the first plate is less than the height of the boss 112 relative to the first plate, so that a certain space is reserved between the explosion-proof valve 14 and the casing for venting.

[0063] like Figure 2 As shown, in some embodiments of the present invention, the distance between the boss 112 and the explosion-proof valve 14 along the length of the substrate 111 is L2, where 8mm ≤ L2 ≤ 12mm. The explosion-proof valve 14 and the substrate 111 are typically connected by welding, with the periphery of the explosion-proof valve 14 welded to the substrate 111. If L2 is too small, it will affect the welding between the explosion-proof valve 14 and the substrate 111; if L2 is too large, it will reduce the size of the boss 112 along the length of the substrate 111, which is not conducive to improving the support strength of the boss 112.

[0064] like Figure 2 As shown, in some embodiments of the present invention, the distance between the boss 112 and the edge of the substrate 111 in the width direction of the substrate 111 is A, 3mm≤A≤10mm, that is, the distance between the two side edges of the substrate 111 extending along its length direction and the boss 112 is between 3mm and 10mm.

[0065] The substrate 111 and the cell housing 200 are typically connected by welding, with the periphery of the substrate 111 welded to the opening of the cell housing 200. If the value of A is too small, it will affect the welding between the substrate 111 and the cell housing 200, and after the outer insulating film 400 is wrapped around the outside of the cell housing 200, the width of the outer insulating film 400 folded onto the substrate 111 is small, which may cause the outer insulating film 400 to warp. If the value of A is too large, it will reduce the size of the boss 112, reduce the support strength of the boss 112, and the material ejected from the explosion-proof valve 14 may easily reach the electrode post 12, affecting the thermoelectric isolation effect.

[0066] In some embodiments of the present invention, the boss 112 is symmetrically arranged about the center line of the substrate 111 along its length direction, and the explosion-proof valve 14 is symmetrically arranged about the center line of the substrate 111 along its length direction. That is, the distance A between the two edges of the substrate 111 extending along its length direction and the boss 112 is equal, and the distance B between the two edges of the substrate 111 extending along its length direction and the explosion-proof valve 14 is equal, which is beneficial to improving the thermoelectric isolation effect.

[0067] The width of the boss 112 in the width direction of the substrate 111 is W1, and the width of the explosion-proof valve 14 in the width direction of the substrate 111 is W2, where 0.5 ≤ W2 / W1 ≤ 0.8. If W2 / W1 is too large when W2 is constant, it indicates that the width of the boss 112 is too small, which will affect the support strength and thermoelectric isolation effect of the boss 112. If W2 / W1 is too small while ensuring the width W1 of the boss 112, it indicates that the width of the explosion-proof valve 14 is too small, which will affect the venting performance of the battery cell.

[0068] In traditional battery pack structures, the heat of the cells is dissipated only through natural heat exchange between the busbars and terminals and the air, resulting in low heat dissipation efficiency and easy heat accumulation.

[0069] In some embodiments of the present invention, the supporting surface 1121 of the boss 112 is adapted to support and thermally connect with the battery pack housing, and the end face of the pole 12 away from the substrate 111 in its protruding direction is adapted to thermally connect with the housing, so that the heat of the battery cell can be transferred to the housing through the boss 112 and the pole 12, thereby improving the heat dissipation efficiency of the battery cell. The total projected area of ​​the battery cell cover plate 100 in the thickness direction of the substrate 111 is S, the total area of ​​the supporting surfaces 1121 of all bosses 112 is S5, and the total area of ​​the end faces of all poles 12 is S6, where 0.3≤(S5+S6) / S≤0.55.

[0070] The projected area S of the cell cover 100 on the thickness direction of the substrate 111 is equivalent to the projected area of ​​the area enclosed by the outer periphery of the substrate 111 on its thickness direction. The total area of ​​the supporting surfaces 1121 of all the bosses 112 is S5, and the total area of ​​the end faces of all the poles 12 is S6. S5 + S6 is the heat conduction area between the cell cover 100 and the housing.

[0071] For example, see Figure 1 The cover plate body 11 is provided with two protrusions 112 and two poles 12. The area of ​​the supporting surface 1121 of each protrusion 112 is equal and is S5'. The area of ​​the end face of each pole 12 is equal and is S6'. Then the total area of ​​the supporting surface 1121 of all protrusions 112 is S5=2S5', and the total area of ​​the end face of all poles 12 is S6=2S6'.

[0072] For cells of the same specifications, S6 is relatively fixed. If the value of (S5+S6) / S is too large, it indicates that the area of ​​the support surface 1121 of the boss 112 is large, which will cause the distance between the boss 112 and the terminal post 12 to be too close, increasing the risk of creepage and arcing, and affecting the electrical performance and safety performance of the cell. If the value of (S5+S6) / S is too small, it indicates that the area of ​​the support surface 1121 of the boss 112 is too small, affecting the heat dissipation efficiency of the cell. By setting 0.3≤(S5+S6) / S≤0.55, the risk of creepage is reduced, balancing the electrical performance, safety performance and heat dissipation efficiency of the cell.

[0073] Furthermore, the value of (S5+S6) / S also satisfies 5.0 A / mm. 2 ≤1.2UC / (100×(S5+S6) / S)≤8.5A / mm 2 Where U is the rated capacity of the battery cell, C is the charge / discharge rate of the battery cell, and their product UC is the maximum overcurrent requirement of the battery cell. The units for S5, S6, and S are mm. 2 U is measured in Ah. C is a dimensionless ratio, implying the physical meaning of the reciprocal of time, reflecting the cell's ability to release its rated capacity per hour. The greater the maximum overcurrent demand, the greater the heat generated by the cell. Poor heat dissipation will lead to an increase in cell temperature, affecting cell performance. This embodiment ensures that the thermal conductivity area of ​​the cell cover 100 and the housing meets the cell's maximum overcurrent demand, further guaranteeing the cell's heat dissipation effect.

[0074] like Figure 1 As shown, the battery cell cover 100 provided in some embodiments of the present invention includes two pole posts 12, and the cover body 11 has two bosses 112. In the length direction of the substrate 111, the two pole posts 12 are respectively disposed on both sides of the explosion-proof valve 14, and the two bosses 112 are respectively disposed on both sides of the explosion-proof valve 14, and a boss 112 is provided between each pole post 12 and the explosion-proof valve 14.

[0075] Optionally, along the length of the substrate 111, the explosion-proof valve 14 is located at the center of the substrate 111, the distance between the two bosses 112 and the explosion-proof valve 14 is equal, and the distance between the two pole posts 12 and the explosion-proof valve 14 is also equal. Along the width of the substrate 111, the explosion-proof valve 14, the bosses 112, and the pole posts 12 are all located at the center of the substrate 111.

[0076] like Figure 3 , Figure 4 and Figure 5As shown, the battery cell cover 100 provided in some embodiments of the present invention further includes an insulating member 15, which is connected to the side of the substrate 111 away from the boss 112. A groove 13 is formed on the side of the cover body 11 away from the boss 112, corresponding to the position of the boss 112. A protrusion 151 is provided on the side of the insulating member 15 near the cover body 11, and the protrusion 151 is located within the groove 13. A recessed groove 152 is formed on the side of the insulating member 15 away from the substrate 111, corresponding to the position of the protrusion 151. The recessed groove 152 is used to accommodate the tabs 34 of the electrode assembly 300. A terminal post 12 passes through the insulating member 15 and the substrate 111 and protrudes from the surface of the plate.

[0077] In this design, a recessed groove 152 is formed on the side of the insulating member 15 away from the substrate 111, corresponding to the position of the protrusion 151. The insulating member 15 is located between the cover plate body 11 and the electrode assembly 300, defining a space for accommodating the tab 34 between the recessed groove 152 and the electrode assembly 300, thereby making full use of the internal space of the hollow protrusion 112. In this way, the groove 13 of the cover plate body 11 can not only reduce the weight of the cover plate body 11 to reduce the weight of the cell and battery pack, but also accommodate the tab 34 of the electrode assembly 300, allowing for a larger space inside the cell to accommodate the body of the electrode assembly 300. This is beneficial for increasing the space utilization rate within the cell casing 200, thereby further increasing the capacity of the cell.

[0078] Furthermore, the protrusion 151 and the groove 13 are contoured. It can be understood that the shape of the groove 13 of the cover body 11 is adapted to the shape of the protrusion 151 of the insulating member 15, so as to make greater use of the internal space of the boss 112.

[0079] like Figure 8 As shown, the battery cell cover plate 100 provided in some embodiments of the present invention further includes a connecting piece 17. The connecting piece 17 includes a first contact portion 171, a connecting portion 173, and a second contact portion 172 connected sequentially along the length direction of the substrate 111. The first contact portion 171 is connected to the electrode post 12, and the second contact portion 172 is located in the recess 152 and is used to connect to the electrode tab 34. The first contact portion 171 and the second contact portion 172 are arranged parallel to each other and are arranged at an angle to the connecting portion 173.

[0080] Specifically, the first contact portion 171 and the second contact portion 172 are arranged parallel to the substrate 111 and spaced apart in the thickness direction of the substrate 111. The two ends of the connecting portion 173 are respectively connected to the first contact portion 171 and the second contact portion 172 to form a "Z"-shaped connecting piece 17 structure. Optionally, the connecting portion 173 extends along the thickness direction of the substrate 111, that is, the connecting portion 173 is perpendicular to the first contact portion 171 and the second contact portion 172.

[0081] In some embodiments of the present invention, the depth of the groove 152 is H3, where 3mm ≤ H3 ≤ 6mm. If the depth of the groove 152 is too small, it will not be able to accommodate the tab 34, which will increase the distance between the substrate 111 and the electrode assembly 300, which is not conducive to improving the cell capacity. If the depth of the groove 152 is too large, the height of the boss 112 will be too high, which will increase the distance between the substrate 111 and the battery pack housing, resulting in wasted internal space of the housing, which is not conducive to improving the battery capacity. Through experimental verification, after adopting this structure, the height of the insulating component 15 in the thickness direction of the substrate 111 is reduced to 3~5mm (the existing structure is 6mm-9mm). Correspondingly, the height of the electrode assembly 300 inside the cell can be increased by 3mm-5mm based on the existing technology, and the single cell capacity is increased by 1.2-1.7%.

[0082] The battery cell cover 100 provided in this embodiment of the invention also includes a protective patch 16, such as... Figure 17 As shown, the protective patch 16 is attached to the first surface of the substrate 111, forming an insulating protection for the cell cover 100 and avoiding the electrolyte injection hole 1123. In a conventional cell cover 100, there is a gap between the protective patch 16 and the terminal post 12. During the electrolyte injection process, the electrolyte can easily come into contact with the terminal post 12 through the gap, causing contamination of the terminal post 12 and affecting the safety performance of the cell.

[0083] To address this, embodiments of the present invention provide a novel protective patch 16. For example... Figure 14 As shown, the protective patch 16 includes a substrate 161 and a protective structure 162. The substrate 161 is adhered to the substrate 111, and the substrate 161 has a through hole 1611 for the protruding structure to pass through. The protective structure 162 includes a retaining portion 1621, which is connected to the substrate 161 and surrounds the through hole 1611. The retaining portion 1621 protrudes from the substrate 161 along the thickness direction of the substrate 161.

[0084] The protective structure 162 and the substrate 161 are integrally formed. The thickness direction of the substrate 161 is consistent with the thickness direction of the substrate 111, the length direction of the substrate 161 is consistent with the length direction of the substrate 111, and the width direction of the substrate 161 is consistent with the width direction of the substrate 111. The protruding structure can be a pole post 12 protruding from the surface of the first plate.

[0085] The substrate 161 is attached to the substrate 111, and the protective structure 162 is correspondingly provided with the raised structure. The raised structure passes through a through-hole 1611 in the substrate 161, and a retaining portion 1621 surrounds the raised structure. The retaining portion 1621 has a certain height relative to the substrate 161 in the thickness direction. When the raised structure is an electrode post 12, during the electrolyte injection process, the electrolyte flowing onto the protective patch 16 can be blocked by the retaining portion 1621, preventing the electrolyte from contacting the electrode post 12.

[0086] like Figure 14 As shown, in some embodiments of the present invention, the protective structure 162 further includes a cover portion 1622, which is connected to the end of the enclosure portion 1621 away from the substrate 161. The cover portion 1622 is disposed circumferentially along the enclosure portion 1621 and extends inwardly towards the enclosure portion 1621 in a direction parallel to the substrate 161, forming an opening opposite to the through hole 1611. The cover portion 1622 is used to cover the periphery of the end of the protruding structure away from the plate surface. In this way, the reliability of the protective structure 162 can be enhanced, the enclosure portion 1621 can be prevented from tearing, and more effective protection can be provided for the protruding structure.

[0087] like Figures 14-16 As shown, in some embodiments of the present invention, the protective structure 162 corresponding to the pole post 12 is a first protective structure. The covering portion 1622 of the first protective structure is provided with a first notch 16231, through which the busbar 500 connected to the pole post 12 can pass. The enclosure portion 1621 of the first protective structure is provided with a second notch 16232 corresponding to the position of the first notch 16231. The first notch 16231 and the second notch 16232 are connected to form an avoidance notch 1623.

[0088] The first notch 16231 and the second notch 16232 have the same dimensions along the length of the substrate 161. When the busbar 500 is connected to the pole post 12, the busbar 500 passes through the clearance notch 1623, and there is a certain distance between the blocking part 1621 and the covering part 1622 and the busbar 500. During the welding of the busbar 500 and the pole post 12, the heat of welding can be avoided from causing the protective patch 16 to melt.

[0089] In some embodiments of the present invention, the protruding structure may also be a boss 112, which is connected to the surface of the substrate 111 to form the cover body 11 of the cell cover 100. The protective structure 162 corresponding to the boss 112 is a second protective structure, and the covering portion 1622 of the second protective structure is annular.

[0090] It is understood that the number of protruding structures is at least two, at least one being a pole post 12 and at least one being a boss 112. The number of first protective structures is the same as the number of pole posts 12, and the number of second protective structures is the same as the number of bosses 112. The cover portion 1622 of the first protective structure covers the edge region of the pole post 12 at the end away from the plate surface. The cover portion 1622 of the second protective structure covers the edge region of the boss 112 at the end away from the plate surface.

[0091] The boss 112 is used for connection with the battery pack housing or for expanding the internal space of the battery cell. The cover body 11 is usually made of metal. When the space on the substrate 111 is limited, the enclosure part 1621 and the covering part 1622 of the second protective structure wrap around the periphery of the boss 112 and the edge of the support surface 1121 on the side away from the substrate 111, thereby separating the pole post 12 and the boss 112, improving the insulation effect of the protective patch 16, and reducing the risk of creepage and arcing of the battery cell.

[0092] The protective patch 16 has its covering portion 1622 attached to the end of the raised structure away from the board surface. This increases the adhesive area of ​​the protective patch 16 and prevents it from peeling off due to insufficient adhesive area.

[0093] Optionally, such as Figure 15 As shown, the overlap width between the cover portion 1622 of the protective patch 16 and the raised structure in the direction towards the inside of the enclosure portion 1621 is W5, where 2mm ≤ W5 ≤ 5mm. If the W5 value is too small, the protective effect will be poor; if the W5 value is too large, it will reduce the opening area and affect the welding effect of the terminal post 12 and the busbar 500 or the bonding area between the boss 112 and the battery pack casing.

[0094] When an explosion-proof valve 14 is provided on the substrate 111, such as Figure 14 As shown, in some embodiments of the present invention, the substrate 161 is further provided with an opening 1612, which is opposite to the explosion-proof valve 14, and the edge of the opening 1612 circumferentially surrounds the outside of the explosion-proof valve 14. It can be understood that the opening 1612 on the substrate 161 provides clearance from the explosion-proof valve 14, preventing the protective patch 16 from obstructing the opening of the explosion-proof valve 14 or affecting the opening pressure of the explosion-proof valve 14.

[0095] Optionally, the thickness of the protective patch 16 is T3, where 0.2mm ≤ T3 ≤ 0.5mm. If the T3 value is too small, the insulation of the protective patch 16 will be poor, resulting in arcing and short circuit problems; if the T3 value is too large, it will waste materials and increase costs.

[0096] like Figure 6 As shown, this embodiment of the invention also provides a battery cell, which includes a battery cell housing 200, an electrode assembly 300, and a battery cell cover plate 100 as described in any of the above embodiments. The battery cell housing 200 has an opening, and the battery cell cover plate 100 is disposed at the opening and surrounds the battery cell housing 200 to form a receiving cavity. The electrode assembly 300 is disposed within the receiving cavity, and the electrode tabs 34 of the electrode assembly 300 are connected to the electrode posts 12.

[0097] Furthermore, such as Figure 8As shown, the tab 34 of the electrode assembly 300 is bent and housed within the recess 152 of the insulating member 15 and connected to the electrode post 12 via a connecting piece 17. The recess 152 has a first groove wall 1521 and a second groove wall 1522 that are opposite each other in the longitudinal direction of the substrate 111. In the longitudinal direction of the substrate 111, the tab 34 is located within the space defined by the connection portion 173 of the second groove wall 1522 and the connecting piece 17, and there are gaps between the second groove wall 1522 and the connecting piece 17 and the tab 34.

[0098] Specifically, the connecting portion 173 of the connecting piece 17 is close to the first groove wall 1521, and the second contact portion 172 is located within the recess 152 and extends along the length direction of the substrate 111. Along the length direction of the substrate 111, the electrode tab 34 is located between the second groove wall 1522 and the connecting portion 173, with one end of the electrode tab 34 close to the connecting portion 173 and the other end close to the second groove wall 1522. By providing gaps between the electrode tab 34 and both the second groove wall 1522 and the connecting portion 173, structural interference between the electrode tab 34 and the recess 152 and the connecting piece 17 during assembly, and to prevent damage to the electrode tab 34, are avoided.

[0099] like Figure 8 As shown, in some embodiments of the present invention, the size of the tab 34 is L3 along the length of the substrate 111, the distance between the second groove wall 1522 and the connecting piece 17 is L4, the spacing between the tab 34 and the second groove wall 1522 is G1, and the spacing between the tab 34 and the connecting piece 17 is G2, wherein 0.85≤L3 / L4≤0.9, 2mm≤G1≤5mm, and 2mm≤G2≤5mm. If G1 and G2 are too small, the tab 34 is prone to interference with the connecting piece 17 and the second groove wall 1522 when the tab 34 is welded to the connecting piece 17; if G1 and G2 are too large, it will waste space and make the boss 112 too long along the length of the substrate 111, which will cause the boss 112 to be too close to the pole 12, increasing the risk of creepage.

[0100] In some embodiments of the present invention, in the thickness direction of the substrate 111, there is a gap between the portion of the connecting piece 17 connected to the pole post 12 and the pole group 300, and the distance between the connecting piece 17 and the pole group 300 is H4, 0.2mm≤H4≤0.5mm.

[0101] Specifically, the electrode assembly 300 includes an electrode assembly 300 body and a tab 34. The tab 34 is connected to the electrode assembly 300 body and welded to the second contact portion 172 of the connecting piece 17. In the thickness direction of the substrate 111, there is a gap between the first contact portion 171 connected to the pole post 12 and the electrode assembly 300 body, and the distance between the two is H4. If H4 is too small, the first contact portion 171 is easy to damage the electrode assembly 300; if H4 is too large, it will cause waste of internal space of the cell.

[0102] like Figure 7 As shown, the battery cell provided in this embodiment of the invention also includes an insulating film 400, which is located between the electrode group 300 and the battery cell housing 200 and wraps around the electrode group 300. The battery cell has a cubic structure, and the insulating film 400 wraps around the outside of the cubic electrode group 300. During battery cell assembly, the insulating film 400 is a pre-cut sheet of insulating film.

[0103] Specifically, such as Figure 9 As shown, the electrode assembly 300 has a first end face 33 and a second end face facing away from each other, and two first side faces 31 and two second side faces 32 connected between the first end face 33 and the second end face. The two first side faces 31 are arranged facing away from each other, and the two second side faces 32 are arranged facing away from each other. The first end face 33 is connected to an electrode tab 34.

[0104] like Figure 10 As shown, the insulating film 400 includes a first film group 41 and a second film group 42. The first film group 41 includes a first film body 411, a second film body 412, and a third film body 413 connected sequentially along a first direction. The second film body 412 has a clearance hole 4121 for the electrode tab 34 to pass through. A second film group 42 is connected to each end of the first film group 41 in a second direction. The second film group 42 includes a first folded body 421, a second folded body 422, and a third folded body 423 distributed along the first direction. The first folded body 421 is connected to the first film body 411, the second folded body 422 is connected to the second film body 412, and the third folded body 423 is connected to the third film body 413. The first direction and the second direction are perpendicular.

[0105] The first membrane 411 and the third membrane 413 can be folded and connected relative to the second membrane 412, respectively. The first folding body 421, the second folding body 422, and the third folding body 423 of each second membrane group 42 can be folded and connected relative to the first membrane group 41, so that the first membrane group 41 and the two second membrane groups 42 form a box structure. The second membrane 412 is wrapped around the first end face 33, and the tab 34 passes through the clearance hole 4121. The first membrane 411 and the third membrane 413 are respectively wrapped around the two first side faces 31 and the second end face, respectively. The two second membrane groups 42 are folded relative to the first membrane group 41 and are wrapped around the two second side faces 32 one by one.

[0106] Two second membrane units 42 are respectively connected to both sides of the first membrane unit 41. A first folding body 421 is connected to both sides of the first membrane 411, a second folding body 422 is connected to both sides of the second membrane 412, and a third folding body 423 is connected to both sides of the third membrane 413.

[0107] See Figure 9 and Figure 12When the insulating film 400 is wrapped around the electrode assembly 300, the second film 412 can be wrapped around the first end face 33, and the electrode tab 34 can be passed through the clearance hole 4121. The first film 411 and the third film 413 are both folded relative to the second film 412, so that the first film 411 is wrapped around at least a part of a first side face 31 and a second end face, and the other second film 412 is wrapped around at least a part of another first side face 31 and a second end face. Then, the first folding body 421 of one of the second membrane groups 42 is folded relative to the first membrane body 411, the second folding body 422 is folded relative to the second membrane body 412, and the third folding body 423 is folded relative to the third membrane body 413. The first folding body 421, the second folding body 422, and the third folding body 423 are stacked on one second side surface 32. Similarly, the first folding body 421, the second folding body 422, and the third folding body 423 of the other second membrane group 42 are stacked on another second side surface 32.

[0108] Understandably, the insulating film 400 wraps around the six sides of the electrode assembly 300, forming a cubic box structure. The first membrane 411 and the third membrane 413 can be fixedly connected by adhesive, as can the first folded body 421, the second folded body 422, and the third folded body 423.

[0109] In conventional technology, the insulating film 400 only covers four sides of the electrode assembly 300. This requires thermally fusing the insulating film 400 to the insulating component 15 on the cell cover 100. If the insulating component 15 is too thin, the yield of the thermal fusion fixation between the insulating film 400 and the insulating component 15 will be reduced, affecting the cell's performance. In this embodiment of the invention, the insulating film 400 can completely cover all six sides of the cubic electrode assembly 300, eliminating the need for thermal fusion fixation between the insulating film 400 and the insulating component 15 on the cell cover 100. This prevents the adverse effects on cell performance caused by a low yield of thermal fusion between the insulating film 400 and the insulating component 15. Furthermore, since the insulating film 400 completely covers the outer surface of the electrode assembly 300, it avoids contact short circuits between the electrode assembly 300 and the casing, improving the insulation of the insulating film 400 inside the cell and reducing the risk of contact short circuits between the electrode assembly 300 and the casing.

[0110] like Figure 10 As shown, in this embodiment of the invention, a crease is provided at the connection between the first membrane 411 and the second membrane 412, and a crease is provided at the connection between the second membrane 412 and the third membrane 413. A crease is provided at the connection between the first folding body 421 and the first membrane 411, a crease is provided at the connection between the second folding body 422 and the second membrane 412, and a crease is provided at the connection between the third folding body 423 and the third membrane 413. The insulating film 400 can be permanently creased using mechanical indentation or thermal indentation methods to facilitate the wrapping of the electrode assembly 300 with the insulating film 400.

[0111] In some embodiments of the present invention, the distance between the creases at both ends of the second membrane 412 in the first direction and the clearance hole 4121 is D1, where D1 ≥ 1 mm. This ensures that the second membrane 412 covers the edge of the second end face. If the value of D1 is too small, when the insulating film 400 wraps the electrode group 300, it is easy to cause a short circuit when the portion of the first side 31 or the second side 32 near the first end face 33 comes into contact with the housing.

[0112] like Figure 10 As shown, in some embodiments of the present invention, the first membrane 411 includes a first wrapping portion 4111 and a second wrapping portion 4112. The first wrapping portion 4111 is connected to the second membrane 412. The third membrane 413 includes a third wrapping portion 4131 and a fourth wrapping portion 4132, with the third wrapping portion 4131 connected to the second membrane 412. The second wrapping portion 4112 is foldable relative to the first wrapping portion 4111, and the fourth wrapping portion 4132 is foldable relative to the third wrapping portion 4131, such that the second wrapping portion 4112 and the fourth wrapping portion 4132 at least partially overlap and are opposite to the second membrane 412.

[0113] The first wrapping portion 4111 and the third wrapping portion 4131 respectively cover the two first side surfaces 31 of the electrode assembly 300. The second wrapping portion 4112 is folded over the first wrapping portion 4111 and covers at least a portion of the second end face. The fourth wrapping portion 4132 is folded over the third wrapping portion 4131 and covers at least a portion of the second end face. The second wrapping portion 4112 and the fourth wrapping portion 4132 overlap and cover the second end face, and the two can be fixedly connected by adhesive.

[0114] Optionally, a crease is provided at the connection between the first wrapping part 4111 and the second wrapping part 4112, and a crease is provided at the connection between the third wrapping part 4131 and the fourth wrapping part 4132. This crease can be formed by mechanical indentation or thermal indentation.

[0115] See Figure 10 and Figure 11 In some embodiments of the present invention, the second membrane 412 is provided with a plurality of vent holes 4122, and the explosion-proof valve 14 is disposed opposite to the plurality of vent holes 4122. The plurality of vent holes 4122 can connect the interior of the electrode assembly 300 and the explosion-proof valve 14, so that the gas generated in the electrode assembly 300 can be discharged from the plurality of vent holes 4122 and then discharged from the housing through the explosion-proof valve 14. Optionally, the plurality of vent holes 4122 are arranged in a matrix, forming a relatively uniform exhaust area on the end face of the electrode assembly 300, which is conducive to the smooth exhaust of the electrode assembly 300.

[0116] Optionally, such as Figure 13As shown, the overlap width of the second wrapping portion 4112 and the fourth wrapping portion 4132 is W3, and the width of the second membrane 412 in the first direction is W4, 2mm≤(W4-W3) / 2≤4mm.

[0117] It is understandable that for the cubic structure of the pole group 300, the first end face 33 and the second end face of the pole group 300 are the same. Accordingly, after the second wrapping portion 4112 and the fourth wrapping portion 4132 overlap, the total width in the first direction is equal to the width W4 of the second membrane 412 in the first direction, and the overlap width W3 of the second wrapping portion 4112 and the fourth wrapping portion 4132 is less than W4.

[0118] In this embodiment, by setting 2mm ≤ (W4-W3) / 2 ≤ 4mm, it is ensured that the second wrapping portion 4112 and the fourth wrapping portion 4132 do not exceed the range of the second end face, and that they have sufficient overlap width. The overlapping portion serves to support the electrode assembly 300, replacing the tray in the existing cell structure, simplifying the cell assembly process, and improving production efficiency. If (W4-W3) / 2 is too small, interference may easily occur when covering the insulating film 400, resulting in a loose insulating film 400 after wrapping, which is not conducive to the insertion of the electrode assembly 300 into the casing. If (W4-W3) / 2 is too large, it will reduce the overlap area of ​​the second wrapping portion 4112 and the fourth wrapping portion 4132, reducing their supporting effect on the electrode assembly 300.

[0119] Optionally, the first folded body 421, the second folded body 422, and the third folded body 423 of the same second membrane assembly 42 are bonded and fixed together. The end of the first membrane body 411 away from the second membrane body 412 and the end of the third membrane body 413 away from the second membrane body 412 are bonded and fixed together. For example, they are bonded and fixed together with tape or glue, so that the folded second membrane assembly 42 forms a whole and wraps around the second side 32, with the second wrapping portion 4112 of the first membrane body 411 and the fourth wrapping portion 4132 of the third membrane body 413 wrapping around the second end face.

[0120] When the first folding body 421, the second folding body 422, and the third folding body 423 are folded to the second side 32, the stacking order of the three is not restricted. For example, see Figure 12 The first folding body 421 and the third folding body 423 can be pressed onto the outside of the third folding body 423.

[0121] like Figure 11As shown, in some embodiments of the present invention, the spacing between the tabs 34 and the second films 412 in the width direction of the tabs 34 is D2, where 2mm ≤ D2 ≤ 5mm. The width direction of the tabs 34 is consistent with the length direction of the substrate 111. The tabs 34 are located within the clearance holes 4121, and a certain spacing D2 exists between each end of the tab 34 and the second film 412 in the width direction. If the value of D2 is too small, the tabs 34 are prone to interference with the insulating film 400 when they are inserted; if the value of D2 is too large, the area of ​​the second film 412 will be reduced, and the second film 412 will be easily deformed.

[0122] This invention also provides a battery module, which includes a busbar 500 and a plurality of battery cells as described in any of the above embodiments. The end of the terminal post 12 away from the electrode assembly 300 is connected to the busbar 500. In the thickness direction of the substrate 111, the height of the side of the busbar 500 away from the terminal post 12 relative to the surface of the substrate 111 is less than the height of the boss 112 relative to the surface of the substrate 111.

[0123] The battery module is suitable for assembly into a housing to form a battery pack. The side of the housing facing the terminal post 12 of the battery module can be set as a flat surface, so that when the housing is supported and connected to the protrusion 112 at the end of each cell on the battery module, there is still a certain distance between the busbar 500 and the housing, which helps to ensure that the housing does not cause squeezing damage to the busbar 500 and the terminal post 12.

[0124] In some embodiments of the present invention, the battery module includes a plurality of battery cells arranged sequentially along the width and / or length direction of the substrate 111. Adjacent battery cells can be connected via a busbar 500.

[0125] In some embodiments of the present invention, the busbar 500 passes through the clearance notch 1623 along the width or length direction of the substrate 161. The distance between the busbar 500 and the cover portion 1622 at the clearance notch 1623 in the length or width direction of the substrate 161 is G3, and the depth of the clearance notch 1623 in the thickness direction of the substrate 161 is G4, where 5mm≤G3≤10mm and 2mm≤G4≤4mm. This ensures a safe distance between the busbar 500 and the protective structure 162, preventing the protective structure 162 from being thermally melted due to heat generated during the welding process of the busbar 500 and the electrode post 12.

[0126] Among them, such as Figure 15 and Figure 16As shown, the clearance notch 1623 is provided facing the width direction of the substrate 161, and the bus passes through the clearance notch 1623 along the width direction of the substrate 161. In this case, the distance between the bus and the cover portion 1622 at the clearance notch 1623 in the length direction of the substrate 161 is G3. Alternatively, the clearance notch 1623 may also be provided facing the length direction of the substrate 161, and the bus passes through the clearance notch 1623 along the length direction of the substrate 161. In this case, the distance between the bus and the cover portion 1622 at the clearance notch 1623 in the width direction of the substrate 161 is G3.

[0127] Optionally, in the width direction of the substrate 111, the bosses 112 of a plurality of battery cells are disposed opposite to each other and arranged to form strip-shaped baffles. When the explosion-proof valve 14 is located between two bosses 112, two strip-shaped baffles are formed on both sides of the explosion-proof valve 14 of the plurality of battery cells arranged in the width direction of the substrate 111. An exhaust channel is defined between the two strip-shaped baffles, and the gas discharged from the explosion-proof valve 14 can be discharged to the outside of the battery pack along the exhaust channel.

[0128] The length dimension L of the substrate 111 is defined as L, and the width dimension W of the substrate 111 is defined as W. Based on the parameter value ranges defined in this embodiment of the invention, different DOE experimental designs were conducted on cover plate bodies 11 with dimensions of 150mm≤L≤300mm and 25mm≤W≤75mm, and corresponding experiments were performed, obtaining the experimental data shown in Tables 1 to 6.

[0129] Experiment 1: The battery pack was simulated and the cells were tested for safety according to national standards. Simulation analysis was used to determine whether the stress at the cell terminals changed significantly when the battery pack was subjected to mechanical impact along the thickness of the substrate. If no significant change was observed, five more cells were randomly selected for safety testing. If no significant fire or explosion was observed, the test was considered passed. The experimental results are shown in Table 1. The units for L, W, L1, L2, W1, W2, H1, H2, and A in Table 1 are mm.

[0130] Table 1: Experimental Data 1

[0131] Table 1 shows the experimental results: when a boss is added to the cell cover plate and the design requirements of the above embodiments are met, no significant deformation occurs at the cell terminals during simulation analysis, and all cell safety tests are passed. When the boss height is insufficient, the terminals show slight deformation after the mechanical impact test. When the boss width does not match the explosion-proof valve width design, and W2 / W1 is too large, the thermoelectric separation effect is not obvious. When the boss is too wide, the boss edge distance is too small, which will affect the yield of the outer insulating film covering the cell.

[0132] Experiment 2: The cell cover plate has two identical bosses and two identical terminals. The substrate has two first through holes corresponding to the two terminals and one second through hole corresponding to the explosion-proof valve. The electrolyte injection hole is located on the boss. Simulation analysis was performed on the battery pack. In the simulation analysis, different mechanical impact forces F along the thickness direction of the substrate were applied to the battery pack to determine whether the stress on the support surface of the boss and the first surface of the substrate increased significantly. The experimental results are shown in Table 2. The units of S, S1, S2, and S3 in Table 2 are mm. 2 The unit of F is N, the unit of R is MPa, P1=(2S1+S2) / S, P2=1.3F / 2S5'.

[0133] Table 2: Experimental Data 2

[0134] Table 2 shows the experimental results. When a boss is added to the cell cover and the above design requirements are met, in the simulation analysis, when the battery pack is subjected to different magnitudes of mechanical impact force F along the thickness direction of the substrate, neither the boss nor the substrate undergoes significant deformation, and the structural strength of the boss and the substrate meets the stress requirements. When the area of ​​the boss's supporting surface is insufficient, resulting in 1.3F / 2S1 > R, the material stress value of the boss increases in the simulation analysis, indicating that the force on the boss exceeds its yield strength and does not meet the stress requirements. When (2S1+S2) / S is too large, the material stress value of the substrate increases in the simulation analysis, indicating that the opening area of ​​the substrate is too large, leading to a decrease in substrate strength and failing to meet the stress requirements.

[0135] Experiment 3: The cell cover has two identical bosses and two identical terminals. Simulation analysis was performed on the battery pack to determine whether the maximum temperature at the cell terminals during charging and discharging meets the design requirements (≤55°C). Experimental results are shown in Table 3. The units for S, S5', and S6' in Table 3 are mm. 2 The unit of U is Ah, P3 = (2S5' + 2S6') / S, P4 = 1.2UC / (100 × (2S5' + 2S6') / S).

[0136] Table 3: Experimental Data

[0137] Table 3 shows the experimental results: when a boss is added to the cell cover and the above design requirements are met, the temperature rise at the cell's terminal position meets the design requirements in the simulation analysis. When (2S5'+2S6') / S is too small, and / or when the cell's overcurrent demand does not match the area ratio (2S5'+2S6') / S, the temperature rise will exceed the upper limit, affecting the cell's service life and safety performance.

[0138] Experiment 4: During cell assembly, the tabs and connecting pieces were welded. During the welding process, interference between the tabs and the sink or connecting piece was observed, and the welding yield of the tabs and connecting pieces was statistically analyzed. The experimental results are shown in Table 4. The units for L3, L4, G1, G2, H3, and H4 in Table 4 are mm.

[0139] Table 4: Experimental Data

[0140] Table 4 shows the experimental results: when a boss is added to the cell cover plate and the above design requirements are met, there are no obvious abnormalities in the cell assembly process, and the single cell capacity is increased by 1.2-1.7%. If the gap between the tab and the connecting piece or the slot is too small, interference may easily occur between the welding head protective cover and the connecting piece or insulating part during tab welding, affecting the production yield. When the H4 value is too small, the electrode assembly is prone to damage during assembly.

[0141] Experiment 5: During the wrapping of the insulating film, observe whether interference occurs when the electrode tabs pass through the insulating film, and whether interference occurs at the end of the insulating film. After wrapping, observe the supporting effect of the overlapping parts of the second and fourth wrapping parts on the electrode assembly, and detect whether there is any damage to the electrode assembly using X-ray. The experimental results are shown in Table 5. The units of D1, D2, W3, and W4 in Table 5 are mm.

[0142] Table 5: Experimental Data

[0143] Table 5 shows the experimental results, indicating that the insulating film provided in this embodiment of the invention solves the problem of low yield when the insulating components and the insulating film are hot-melted and fixed. Simultaneously, the traditional internal support plate for the electrode assembly can be eliminated, simplifying the cell assembly process and improving production efficiency. When the insulating film meets the above design requirements, it provides excellent coverage for the electrode assembly, preventing interference and electrode damage issues.

[0144] Experiment 6: Hi-pot high-voltage testing was performed on the battery cells to determine if there was any arcing or short circuit between the terminals and bosses. During battery module assembly, the protective patch was observed for any lifting issues. During the welding of the busbar and terminals, wrinkles appeared on the protective patch to determine if the welding heat had a thermal impact on it. Experimental results are shown in Table 6. The units for T3, W5, G3, and G4 in Table 6 are mm.

[0145] Table 6: Experimental Data

[0146] Table 6 shows the experimental results, indicating that the protective patch provided in this embodiment of the invention ensures insulation performance, avoids contamination of the terminals during liquid injection, and prevents creepage and arcing of the battery cell when bosses are present. During the assembly of the battery cell and battery module, the protective patch does not warp, and the heat from welding the busbar to the terminals avoids thermal effects on the protective patch. When W5 or T3 is too small, the insulation of the protective patch decreases, leading to arcing and short circuits. When G3 or G4 is too small, the protective patch will be affected by heat during busbar welding.

[0147] 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. An electrode cover plate, characterized by, The application relates to a battery cell cover plate, comprising: a cover plate body, comprising a base plate and at least one boss, the base plate having a plurality of through holes arranged at intervals with the boss, the boss being connected to the plate surface of the base plate and protruding along the thickness direction of the base plate, the side of the boss away from the plate surface having a supporting surface, and the side of the cover plate body away from the boss being provided with a groove corresponding to the position of the boss; a pole column, penetrating one of the through holes and protruding from the plate surface; wherein the projection area of the battery cell cover plate in the thickness direction is S, the total area of the plurality of through holes is S0, and 0.07<=S0 / S<=0.

15.

2. The cell cover plate of claim 1, wherein, The boss and the substrate are integrally formed by stamping, a wall thickness of a top wall of the boss is T2, 1.5mm≤T2≤2mm; an area of the support surface of a single boss is S5', a yield strength of the substrate is R, the boss is subjected to a force in the thickness direction F, 1.3F / 2S5'<R; wherein, the unit of S5' is mm 2 , the unit of R is MPa, and the unit of F is N.

3. The cell cover plate of claim 1, wherein, The boss and the base plate are integrally stamped and formed, the thickness of the base plate is T1, the protruding height of the boss relative to the plate surface is H2, 1.5mm<=T1<=3mm, and H2 / T1<=3.

4. The cell cover plate of claim 1, wherein, The boss further has a peripheral side surface, the peripheral side surface being connected between the supporting surface and the base plate, the peripheral side surface being a tapered surface, and the cross section of the tapered surface gradually decreases in the direction away from the base plate.

5. The cell cover plate of claim 4, wherein, The taper of the tapered surface is beta, and 15<=beta<=25.

6. The cell cover plate of claim 1, wherein, The protruding height of the pole column relative to the plate surface is H1, the protruding height of the boss relative to the plate surface is H2, and 1.5mm<=H2-H1<=3.0mm.

7. The cell cover plate of claim 1, wherein, The cover plate body is a manganese-aluminum alloy plate, wherein the content of aluminum is greater than or equal to 98%, and the content of manganese is greater than or equal to 1%. The boss and the base plate are integrally stamped and formed, the tensile strength of the base plate is sigma, the yield strength is R, the elongation is delta, and the elastic modulus is E; wherein 145Mpa<=sigma<=195Mpa, R>=125Mpa, delta>=3%, and 68Gpa<=E<=70Gpa.

8. The cell cover plate according to any one of claims 1 to 7, characterized in that Further comprising: an explosion-proof valve arranged in another through hole, the pole column, the explosion-proof valve and the boss being arranged at intervals along the length direction of the base plate, and the boss being arranged between the pole column and the explosion-proof valve.

9. An electric cell characterized by, The application relates to a battery cell cover plate, comprising: a battery cell shell, a pole group and the battery cell cover plate as claimed in any one of claims 1 to 8; the battery cell shell is provided with an opening, the battery cell cover plate is arranged in the opening and forms a containing cavity together with the battery cell shell, the pole group is arranged in the containing cavity, and the lug of the pole group is connected with the pole column.

10. A battery module, characterized by The application relates to a battery cell cover plate, comprising: a bus bar and a plurality of battery cells as claimed in claim 9, one end of the pole column away from the pole group being connected with the bus bar; in the thickness direction, the height of the side of the bus bar away from the pole column relative to the plate surface is less than the height of the boss relative to the plate surface.

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