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, which is provided with a boss, and the boss comprises a plurality of convex parts sequentially stacked along the thickness direction of the cover plate body; the insulating part comprises a fixing plate and a turnover plate, the fixing plate is located on the side, away from the boss, of the cover plate body and provided with a supporting part protruding towards the side, away from the cover plate body, of the cover plate body, and the turnover plate is connected to the supporting part in a turnover mode so that 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 along the thickness direction of the cover plate body; wherein under the condition that the turnover plate is buckled on the fixing plate, the turnover plate covers the pole column, and the supporting part and the turnover plate are suitable for abutting against the pole group of the battery cell. According to the battery cell cover plate, the contact area of the insulating part and the pole group is increased, and the fixing effect of the insulating part on the pole group is improved, so that the pole group is prevented from moving.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery cell cover plate and a battery cell. BACKGROUND

[0002] Lithium ion battery is widely used in various fields such as transportation power supply, power storage power supply, new energy storage power supply, aerospace and military industry due to its advantages of large capacity, high working voltage, strong charge holding ability and long cycle life.

[0003] The battery cell is the smallest unit of the lithium battery pack, and the battery cell structure in the prior art generally comprises electrolyte, pole group, bare battery cell insulation film, battery cell cover plate and battery cell shell. The battery cell cover plate is an assembly comprising a cover plate body, an insulating piece and a pole, the cover plate body is welded and fixed with the battery cell shell to form a closed space for accommodating the pole group, the insulating piece is arranged on the inner side of the cover plate body for insulation between the cover plate body and the pole group, and the pole is welded with the tab of the pole group. The insulating piece is usually provided with a thickened portion, which is used to press the pole group, and at the same time, a space for accommodating the tab of the pole group between the battery cell cover plate and the pole group can be reserved. However, the contact area between the insulating piece and the pole group is small, the effect of fixing the pole group is poor, and when the battery cell is subjected to external force impact, the pole group is prone to shift, which causes the base of the pole to press the pole group and the tab to be pulled, thereby affecting the safety of the battery cell. SUMMARY

[0004] The present application provides a battery cell cover plate and a battery cell to solve the problem of poor fixing effect of the battery cell cover plate on the pole group in the prior art, and the pole group is prone to shift.

[0005] The present application provides a battery cell cover plate, comprising: a cover plate body provided with a boss, the boss comprising a plurality of convex portions stacked in sequence along the thickness direction of the cover plate body; an insulating piece comprising a fixing plate and a folded plate, the fixing plate being located on the side of the cover plate body away from the boss and having a support portion protruding away from the cover plate body, and the folded plate being connected to the support portion by folding, so that the folded plate can be buckled or opened relative to the fixing plate; a pole arranged through the cover plate body and the fixing plate along the thickness direction of the cover plate body; wherein, in the case that the folded plate is buckled on the fixing plate, the folded plate covers the pole, and the support portion and the folded plate are adapted to abut against the pole group of the battery cell.

[0006] According to the battery cell cover plate provided by the present application, further comprising: an explosion-proof valve, the topmost convex portion is provided with an exhaust hole penetrating through the cover plate body, and the explosion-proof valve is installed on the topmost convex portion and opposite to the exhaust hole.

[0007] According to the electric cell cover plate provided by the application, the number of the support parts, the folding plates and the pole columns is two, and the two support parts, the two folding plates and the two pole columns are arranged one by one in correspondence; the boss is located between the two pole columns, and the exhaust hole is located between the two folding plates.

[0008] According to the electric cell cover plate provided by the application, the side of the cover plate body close to the insulating part is formed with a recess in correspondence with the position of the boss, the fixing plate is matched with the recess, and the side of the fixing plate away from the cover plate body is formed with a groove in correspondence with the position of the recess; in the case that the folding plate is buckled on the fixing plate, the side of the insulating part away from the cover plate body is formed with a sink in correspondence with the position of the groove.

[0009] According to the electric cell cover plate provided by the application, the electric cell cover plate further comprises: The connecting sheet is located between the fixing plate and the folding plate, the connecting sheet comprises a base part and an extension part, the base part is connected to the pole column, and the extension part is located in the groove and used for welding with the pole lug of the pole group; in the case that the folding plate is buckled on the fixing plate, the folding plate covers the base part and the extension part.

[0010] According to the electric cell cover plate provided by the application, the folding plate has a first plate body and a second plate body, the first plate body is folded and connected to the support part; in the case that the folding plate is buckled on the fixing plate, the first plate body covers the base part, the second plate body is located in the groove and covers the extension part; in the width direction of the cover plate body, the width of the second plate body is smaller than the width of the first plate body.

[0011] According to the electric cell cover plate provided by the application, the folding plate is integrally formed with the fixing plate, and the side of the folding plate close to the fixing plate and the support part is formed with a gap extending along a folding line.

[0012] According to the electric cell cover plate provided by the application, the cover plate body comprises a base plate part and a bending part, the bending part is connected with the base plate part at both ends in the length direction of the cover plate body, the bending part is bent relative to the base plate part to form the boss, and the two pole columns are arranged one by one in the two base plate parts.

[0013] The application further provides an electric cell comprising: The electric cell shell is provided with an opening. The electric cell cover plate is arranged in the opening and surrounds the electric cell shell to form an accommodating cavity. A pole group is arranged in the accommodating cavity, and a lug of the pole group is connected with the pole column.

[0014] According to the electric cell provided by the application, in the thickness direction, the welding part of the lug is located between the folded plate of the cell cover plate and the connecting piece, the thickness of the welding part is t, the distance between the second plate body of the folded plate and the extension of the connecting piece is g2, and 0.2mm≤g2-t≤0.5mm; And / or, the pole group has two lugs corresponding to the position of the second plate body of the folded plate, the two lugs are arranged in the width direction of the cover plate body and symmetrically distributed on both sides of the second plate body, the distance between the two lugs in the folded position is G, the size of the second plate body in the width direction is W2, and 2mm≤(G-W2) / 2≤5mm.

[0015] The electric cell cover plate and the electric cell provided by the application have the following advantages. The insulating piece with the fixed plate and the folded plate is arranged, the support part for abutting against the pole group is arranged on the fixed plate, the folded plate is folded and connected to the support part, the folded plate can be buckled or opened relative to the fixed plate, and in the case that the folded plate is buckled to the fixed plate, the folded plate and the support part can abut against the pole group of the electric cell at the same time, the contact area of the insulating piece and the pole group is increased, the fixing effect of the insulating piece on the pole group is improved, the pole group is prevented from moving, the base of the pole column is prevented from pressing the pole group and the lug is prevented from being pulled, and the safety performance of the electric cell is improved. The boss is arranged on the cover plate body, the boss is supported and connected with the box, the distance between the bus bar and the box can be reduced on the premise that the box does not cause extrusion damage to the bus bar and the pole column, the volume of the electric cell is increased, the internal space of the box is fully utilized, the capacity of the electric cell and the energy density of the entire battery pack are improved. The heat of the electric cell can be transmitted to the box through the boss, and the heat dissipation efficiency of the electric cell is improved. The stepped boss is designed, the height of single stamping is reduced on the premise of ensuring the height of the boss, and the structural strength of the boss is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0017] Figure 1 is one of the structural schematic diagrams of the electric cell cover plate provided by the application.

[0018] Figure 2 is Figure 1 is the structural schematic diagram of the electric cell cover plate in another view.

[0019] Figure 3 is Figure 2 is a schematic view of the folding plate of the battery cell cover plate in the open state.

[0020] Figure 4 is a schematic view of the battery cell cover plate provided by the present application.

[0021] Figure 5 is a schematic view of the folding plate of the battery cell cover plate in the open state. Figure 4

[0022] is a schematic view of the battery cell cover plate provided by the present application. Figure 6

[0023] is a schematic view of the pole group of the battery cell provided by the present application. Figure 7

[0024] is a schematic view of the pole group in another view. Figure 8 Figure 7 is a schematic view of the assembly process of the battery cell cover plate and the pole group provided by the present application.

[0025] Figure 9 is a schematic view of the assembly structure of the battery cell cover plate and the pole group provided by the present application.

[0026] Figure 10 Reference signs: 1, cover plate body; 11, boss; 111, first protruding part; 112, second protruding part; 113, reinforcing rib; 12, base plate part; 121, reference surface; 21, pole column; 22, connecting sheet; 221, base part; 222, extension part; 3, explosion-proof valve; 4, insulating piece; 40, sink groove; 401, first groove part; 402, second groove part; 41, fixed plate; 410, recess; 411, lamination part; 4111, first lamination plate; 4112, second lamination plate; 4113, third lamination plate; 41131, first exhaust structure; 4114, first connecting plate; 4115, second connecting plate; 412, support part; 4121, slotted groove; 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, pole group; 50, connecting end surface; 51, pole lug; 52, convex bump; 521, first groove; 522, second groove; 5201, top surface; 5202, side surface.

[0027] DETAILED DESCRIPTION

[0028] ​​In order to make the objects, technical solutions and advantages of the present application clearer, the following will be combined with the accompanying drawings for a clear and complete description of the technical solutions in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based upon the embodiments in the present application, all other embodiments obtained by those ordinarily skilled in the art without creative effort should fall into the protective scope of the present application.

[0029] In the description of the embodiments of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "first" to "fourth" are numbered for the purpose of clearly describing the components of the product, and do not represent any substantial difference. The terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, can be fixedly connected, or detachably connected, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those ordinarily skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances. In addition, the meaning of "multiple" is two or more than two. In the specification and claims, "and / or" means at least one of the connected objects, and the character " / ", generally means that the front and rear associated objects are in an "or" relationship.

[0030] The following will be described in detail. Figures 1-10 The battery cell cover plate and the battery cell of the present application are described.

[0031] As shown in Figure 1 and Figure 2 The battery cell cover plate provided by the embodiments of the present application comprises a cover plate body 1, an insulating piece 4 and a pole 21. The cover plate body 1 is provided with a boss 11, and the boss 11 comprises a plurality of convex portions which are sequentially stacked along the thickness direction of the cover plate body 1. The insulating piece 4 comprises a fixing plate 41 and a folded plate 42. The fixing plate 41 is located on the side of the cover plate body 1 away from the boss 11 and has a support portion 412 protruding away from the side of the cover plate body 1. The folded plate 42 is foldably connected to the support portion 412, so that the folded plate 42 can be buckled or opened relative to the fixing plate 41. The pole 21 is arranged through the cover plate body 1 and the fixing plate 41 along the thickness direction of the cover plate body 1. Wherein, in the case that the folded plate 42 is buckled on the fixing plate 41, the folded plate 42 covers the pole 21, and the support portion 412 and the folded plate 42 are both adapted to abut against the pole group 5 of the battery cell.

[0032] The cell cover plate is applied to a cell, which comprises a cell shell, a pole group 5 and the cell cover plate. The cell shell is provided with an opening, and the cell cover plate is arranged at the opening and cooperates with the cell shell to form a containing cavity, and the pole group 5 is arranged in the containing cavity. The cell shell and the cover plate body 1 are welded to form an outer shell of the cell, thereby protecting the internal components of the cell and being able to withstand certain external impacts. The pole post 21 protrudes from the outer surface of the cover plate body 1 to form a pole post terminal, which is used to be connected with a busbar, so that a plurality of cells are connected through the busbar to form a battery module. The other end of the pole post 21 is located in the containing cavity and is connected with the tab 51 of the pole post 21. The battery module is assembled in a box to form a battery pack.

[0033] The length direction and the width direction of the cover plate body 1 are shown in Figure 1 The thickness direction of the cover plate body 1 is perpendicular to the length direction and the width direction. Specifically, the cover plate body 1 has a first side and a second side opposite in the thickness direction, the first side faces the outside of the cell and is formed with a boss 11, and the pole post 21 protrudes from the first side to form a pole post terminal. The second side faces the pole group 5 in the containing cavity.

[0034] The boss 11 is suitable for supporting connection with the box of the battery pack, and is used to bear the impact force transmitted by the box. The part of the box that supports the connection with the boss 11 can be the shell of the box; or the box comprises a shell and a cold plate, the cold plate is located between the shell and the cell, and the boss 11 supports the connection with the cold plate.

[0035] The boss 11 can be integrally formed on the cover plate body 1; or the boss 11 is welded and fixed with a base plate as an independent structural member to form the cover plate body 1. The boss 11 can be a solid structure; or the boss 11 is an internal hollow structure, that is, the side of the boss 11 facing the containing cavity is recessed, which can reduce the weight of the cell.

[0036] In the case of the boss 11 being an internal hollow structure, optionally, a through hole is provided on the base plate 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 be used to accommodate the tab 51, which is beneficial to increase the space utilization rate in the cell shell, thereby increasing the capacity of the cell. Of course, in the case of not needing to accommodate the tab 51, the through hole can not be provided on the base plate corresponding to the position of the boss 11, which is beneficial to improve the structural strength of the base plate at the position of the boss 11.

[0037] Optionally, the boss 11 is stamped from a plate member. For example, the boss 11 is stamped from a separate plate member and then welded and fixed with the base plate. Or the boss 11 is integrally stamped with the cover plate body 1, so that the cover plate body 1 forms a recess for accommodating the tab 51, and the manufacturing process of the cover plate body 1 is also simplified.

[0038] The boss 11 comprises a plurality of protrusions arranged in a thickness direction of the cover plate body 1. It can be understood that the cross-sectional area of the plurality of protrusions decreases in sequence in the protruding direction of the boss 11, forming a stepped boss 11. When the boss 11 is formed by a stamping process, the boss 11 can be formed by multiple stamping, reducing the height of single stamping, avoiding the breakage of the plate and ensuring the structural strength of the boss 11.

[0039] The insulating piece 4 is arranged on the second side of the cover plate body 1, and is used for insulating and isolating between the cover plate body 1 and the pole group 5. Specifically, the fixed plate 41 has a fitting portion 411 and a support portion 412 protruding from the fitting portion 411. The fitting portion 411 is arranged in abutment with 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, i.e. the support portion 412 is a locally thickened portion on the fixed plate 41. The folded plate 42 and the support portion 412 are arranged in a length direction of the cover plate body 1, and one end of the folded plate 42 in the length direction is connected to the support portion 412 in a folded manner. Optionally, in the length direction of the cover plate body 1, the pole 21 is located between the support portion 412 and the boss 11.

[0040] It can be understood that there is a height difference between the fitting portion 411 and the support portion 412 in the thickness direction of the cover plate body 1. In the case where the folded plate 42 is buckled to the fixed plate 41, at least part of the side of the folded plate 42 away from the fixed plate 41 is flush with the support portion 412, so that the support portion 412 and the folded plate 42 can simultaneously abut against the pole group 5.

[0041] In the conventional battery pack structure, the battery pack only relies on the box to resist external impact, and the area of the plate part of the box opposite to the pole 21 is large. If the rigidity is not enough, deformation is easy to occur. In order to avoid the extrusion damage of the busbar and the pole 21 caused by the deformation of the box, a large space needs to be reserved between the busbar and the box in the structural design, and a support foam is arranged between the two. Some also set concave-convex structures on the plate part of the box to enhance the rigidity and prevent deformation, but these measures will cause a large gap between the battery cell and the box, resulting in a waste of space. If the thickness of the box is increased to increase its rigidity, the weight of the battery pack will also be increased, which is not conducive to the lightweight design of the battery pack. Moreover, the heat of the battery cell cover plate is only conducted and dissipated through the contact between the pole 21 and the busbar, and through the heat radiation of the battery cell cover plate itself, and the heat dissipation efficiency is low, and the heat is easy to accumulate.

[0042] The electric core cover plate provided by the embodiment of the present application is provided with the insulating piece 4 having the fixing plate 41 and the folded plate 42, the fixing plate 41 is provided with the support part 412 for abutting against the pole group 5, the folded plate 42 is connected to the support part 412 in a folded manner, the folded plate 42 can be buckled or opened relative to the fixing plate 41, and in the case that the folded plate 42 is buckled to the fixing plate 41, the folded plate 42 and the support part 412 can simultaneously abut against the pole group 5 of the electric core, the contact area of the insulating piece 4 and the pole group 5 is increased, the fixing effect of the insulating piece 4 on the pole group 5 is improved, and thus the pole group 5 is prevented from moving, the base of the pole 21 is prevented from pressing the pole group 5 and the tab 51 is prevented from being pulled, and the safety performance of the electric core is improved. The boss 11 is arranged on the cover plate body 1, the boss 11 is supported and connected to the box, the shell of the electric core itself also serves as a support force piece, the box is prevented from being deformed greatly, the thickness of the box is reduced, the lightweight design of the battery pack is realized, the distance between the bus bar and the box is reduced on the premise that the box does not cause extrusion damage to the bus bar and the pole 21, the volume of the electric core is increased, the internal space of the box is fully utilized, the capacity of the electric core and the energy density of the whole battery pack are improved. The heat of the electric core can be transmitted to the box through the boss 11, and the heat dissipation efficiency of the electric core is improved. The stepped boss 11 is designed, the height of single stamping is reduced on the premise of ensuring the sufficient height of the boss 11, and the structural strength of the boss 11 is ensured.

[0043] It should be noted that the electric core has two poles 21, which are a positive pole and a negative pole. The number of poles 21 on the electric core cover plate in the embodiment of the present application can be one or two. As shown in the figure, the electric core cover plate is provided with two poles 21, and the boss 11 is located between the two poles 21 in the length direction of the electric core cover plate, so as to better support and protect the poles 21 on both sides. Figure 1

[0044] Optionally, the boss 11 is integrally bent along the length direction of the cover plate body 1, that is, the recess on the second side of the cover plate body 1 penetrates through the opposite two sides of the cover plate body 1 along the width direction of the cover plate body 1. The boss 11 can be made by stamping process, and the bent boss 11 is beneficial to improve the processing stability. Specifically, the cover plate body 1 includes a base plate part 12 and a bent part. The two ends of the bent part in the length direction of the cover plate body 1 are respectively connected with the base plate part 12. The bent part is bent relative to the base plate part 12 to form the boss 11, and the two poles 21 are correspondingly arranged in the two base plate parts 12.

[0045] In some embodiments of the present application, the boss 11 can be supported and connected to the box through the protrusion at the top thereof.

[0046] In some other embodiments of the present application, the electric core cover plate further includes the explosion-proof valve 3. As shown in the figure, the explosion-proof valve 3 is arranged on the cover plate body 1. Figure 1 ​As shown, the topmost protrusion has a vent hole that penetrates the cover plate body 1, and the explosion-proof valve 3 is installed on the topmost protrusion and opposite to the vent hole. The insulating component 4 has a venting structure opposite to the vent hole, and the vent hole and venting structure are connected so that gas inside the battery cell can be discharged from the explosion-proof valve 3.

[0047] 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 supported and connected to the battery pack casing to bear the impact force transmitted from the casing. The part of the casing that is supported and connected to the boss 11 can be the casing shell; or, the casing includes a shell and a cold plate, with the cold plate located between the shell and the battery cell, and the boss 11 supported and connected to the cold plate.

[0048] 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.

[0049] 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.

[0050] 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. The upper surface of the first protrusion 111 is connected to the battery pack housing support, and the vent is provided on the second protrusion 112. 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 to provide more stable support.

[0051] In the embodiment of the present application, the cover plate body 1 has a reference surface 121, which is a plane of one side of the cover plate body 1 provided with the boss 11, and can be formed in the base plate part 12. The boss 11 and the pole 21 are both protruded from the reference surface 121. In the thickness direction of the cover plate body 1, the protruding height of the pole 21 relative to the reference surface 121 is less than the protruding height of the first protruding part 111 relative to the reference surface 121, so that a certain space is reserved between the pole 21 and the box for arranging the bus bar.

[0052] Further, in the structure of the battery module, the height of the bus bar relative to the reference surface 121 is less than the protruding height of the first protruding part 111 relative to the reference surface 121, so that a certain gap exists between the bus bar and the box, which can be used to maintain a safe distance between the bus bar and the box, and also can be used to arrange the glue with heat conduction performance.

[0053] As shown in Figure 3 , in the embodiment of the present application, the fixing plate 41 is provided with a first exhaust structure 41131, and the exhaust hole is communicated with the first exhaust structure 41131. In the thickness direction of the cover plate body 1, the projection of the exhaust hole is located in the projection distribution range of the first exhaust structure 41131. It can be understood that the first exhaust structure 41131 is opposite to the exhaust hole in the thickness direction of the cover plate body 1, and the area surrounded by the outer periphery of the first exhaust structure 41131 covers the area of the exhaust hole, so as to facilitate the exhaust of the explosion-proof valve 3.

[0054] In some optional embodiments, as shown in Figure 2 and Figure 3 , the number of the support parts 412, the turnover plates 42 and the poles 21 are all two, and the two support parts 412, the two turnover plates 42 and the two poles 21 are one-to-one arranged. The boss 11 is located between the two poles 21, and the exhaust hole is located between the two turnover plates 42.

[0055] Specifically, the two support parts 412 are arranged at two ends of the fixing plate 41 in the length direction of the cover plate body 1, the two poles 21 are respectively located at one side of the two support parts 412 close to each other, and the two turnover plates 42 are also located at one side of the two support parts 412 close to each other, and the two turnover plates 42 are respectively used to cover the two poles 21. The two turnover plates 42 are located on both sides of the first exhaust structure 41131, so as to avoid shielding the first exhaust structure 41131.

[0056] In other optional embodiments, as shown in Figure 4 and Figure 5As shown, the fixing plate 41 has two support portions 412 arranged along the length direction of the cover plate body 1. One end of the flip plate 42 is connected to one support portion 412 by folding, so that the flip plate 42 can be buckled or opened relative to the fixing plate 41. In the case where the flip plate 42 is buckled to the fixing plate 41, the other end of the flip plate 42 is connected to the other support portion 412.

[0057] It can be understood that, unlike the above embodiment of arranging two flip plates 42, the present embodiment only arranges one flip plate 42, which is connected between the two support portions 412 when buckled to the fixing plate 41, so as to simplify the assembly steps of the battery cell cover plate and the pole group 5.

[0058] In the present embodiment, the flip plate 42 has a folded connection end and a free end opposite to the folded connection end in the length direction of the cover plate body 1. The folded connection end is connected to one support portion 412 by folding, and the free end is overlapped with the other support portion 412. Specifically, the other support portion 412 is provided with a slot 4121. When the flip plate 42 is buckled to the fixing plate 41, the free end is located in the slot 4121. Optionally, the support portion 412 and the free end are limited in cooperation in the width direction of the cover plate body 1, so as to ensure the accurate positioning of the buckling position of the flip plate 42.

[0059] In the case where the insulating member 4 is provided with only one flip plate 42, as shown in Figure 5 The flip plate 42 is provided with a second exhaust structure 4231. In the case where the flip plate 42 is buckled to the fixing plate 41, the exhaust hole, the first exhaust structure 41131 and the second exhaust structure 4231 are communicated. In the thickness direction of the cover plate body 1, the projection of the exhaust hole is located in the projection distribution range of the first exhaust structure 41131, and the projection of the first exhaust structure 41131 is located in the projection distribution range of the second exhaust structure 4231. In this way, the part of the fixing plate 41 located outside the first exhaust structure 41131 can be prevented from blocking the exhaust hole, and the part of the flip plate 42 located outside the second exhaust structure 4231 can be prevented from blocking the first exhaust structure 41131, which is beneficial to the smooth exhaust of the explosion-proof valve 3.

[0060] Optionally, a plurality of longitudinal and transverse ribs can be arranged in the exhaust hole, which can support the explosion-proof valve 3 and prevent the explosion-proof valve 3 from deforming during welding.

[0061] In the present embodiment, the first exhaust structure 41131 and the second exhaust structure 4231 can each be a single through hole with a large opening. Alternatively, the first exhaust structure 41131 and the second exhaust structure 4231 each include a plurality of through holes with small openings, which can ensure the structural strength of the fixing plate 41 and the flip plate 42.

[0062] As shown in Figure 3 and Figure 5As 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 insulating member 4 away from the cover plate body 1, corresponding to the position of the groove 410.

[0063] 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. 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 boss 11.

[0064] 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.

[0065] In embodiments where the cell cover has two folding plates 42, the folding plates 42 can be adjacent to or spaced apart from the groove 410, or they can extend from the support portion 412 into the groove 410, as long as the two folding plates 42 do not obstruct the first exhaust structure 41131. When the folding plates 42 extend into the groove 410, the folding plates 42 can be configured as bent plates conformally to the fixing plate 41. Optionally, the folding plates 42 extend into the area within the groove 410 corresponding to the first protrusion 111, avoiding obstruction of the exhaust holes on the second protrusion 112.

[0066] In an embodiment where a folding plate 42 is provided on the cell cover, 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 body 1.

[0067] like Figure 3As shown, the cell cover plate further comprises a connecting piece 22 in some embodiments of the present application. The connecting piece 22 is located between the fixed plate 41 and the folding plate 42. The connecting piece 22 comprises a base portion 221 and an extending portion 222. The base portion 221 is connected to the pole 21, and the extending portion 222 is located in the groove 410 for welding with the tab 51 of the pole group 5. In the case that the folding plate 42 is buckled to the fixed plate 41, the folding plate 42 covers the base portion 221 and the extending portion 222.

[0068] Specifically, the connecting piece 22 extends from the pole 21 to the groove 410 according to the shape of the fixed plate 41. The base portion 221 is located outside the groove 410, and the extending portion 222 is located in the groove 410. The base portion 221 and the extending portion 222 are connected by an inclined portion.

[0069] When the cell cover plate is assembled with the pole group 5, the folding plate 42 is first opened, the tab 51 of the pole group 5 is welded with the extending portion 222 located in the groove 410, then the folding plate 42 is buckled to cover the entire connecting piece 22, and also cover the welded part of the tab 51, and finally the end surface of the pole group 5 is abutted with the support portion 412 of the cell cover plate and the folding plate 42. The folding plate 42 covers the welded part of the tab 51, and plays a role of folding and fixing the tab 51.

[0070] As shown in Figure 3 and Figure 5 , the folding plate 42 has a first plate body 421 and a second plate body 422, and the first plate body 421 is folded and connected to the support portion 412. In the case that the folding plate 42 is buckled to the fixed plate 41, the first plate body 421 covers the base portion 221, and the second plate body 422 is located in the groove 410 and covers the extending portion 222.

[0071] It can be understood that when the folding plate 42 is buckled to the fixed plate 41, the side of the first plate body 421 away from the fixed plate 41 is flush with the support portion 412, so that after the cell cover plate is assembled with the pole group 5, the support portion 412 and the first plate body 421 are simultaneously abutted with the end surface of the pole group 5.

[0072] Specifically, as shown in Figure 3As 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.

[0073] In an embodiment where the cell cover has two folding plates 42, each folding plate 42 includes a first plate body 421 and a second plate body 422, and the two folding plates 42 are symmetrically arranged about the boss 11.

[0074] Specifically, such as Figure 3 As shown, the folding plate 42 has a first plate 421, a third connecting plate 424, and a second plate 422 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, and the second plate 422 is opposite to the second bonding plate 4112. Optionally, the folding plate 42 also has a limiting plate 425, which is connected to the end of the second plate 422 away from the first plate 421, and is opposite to the second connecting plate 4115. The limiting plate 425 can be engaged with the second connecting plate 4115 to pre-position the folding plate 42.

[0075] In an embodiment where a folding plate 42 is provided on the cell cover, such as Figure 5As shown, the folding plate 42 has a first plate body 421, a third connecting plate 424, a second plate body 422, a fourth connecting plate 426 and a third plate body 423 connected in sequence to form a stepped plate. The first plate body 421 is opposite the first laminated plate 4111, the third connecting plate 424 is opposite the first connecting plate 4114, the second plate body 422 is opposite the second laminated plate 4112, the fourth connecting plate 426 is opposite the second laminated plate 4112, and the third plate body 423 is opposite the third laminated plate 4113. The two ends of the third plate body 423 are symmetrical to each other and sequentially connected with the fourth connecting plate 426, the second plate body 422, the third connecting plate 424 and the first plate body 421. One of the first plate bodies 421 is foldably connected with one of the support portions 412, and the other first plate body 421 is overlapped with the other support portion 412. The third plate body 423 is provided with a second exhaust structure 4231 which is communicated with the first exhaust structure 41131.

[0076] Optionally, the first connecting plate 4114 is arranged obliquely relative to the second laminated plate 4112, and the second connecting plate 4115 is arranged obliquely relative to the third laminated plate 4113. Correspondingly, the third connecting plate 424 is arranged obliquely relative to the second plate body 422, the limiting plate 425 is arranged obliquely relative to the second plate body 422, and the fourth connecting plate 426 is arranged obliquely relative to the third plate body 423.

[0077] As shown in Figure 2 and Figure 4 In some embodiments of the present application, the width of the second plate body 422 is less than the width of the first plate body 421 in the width direction of the cover plate body 1. Since the welding portion of the tab 51 is arranged between the second plate body 422 and the extension portion 222, the tab 51 needs to be folded and collected in the sink 40. By arranging the width of the second plate body 422 to be less than the width of the first plate body 421, an avoiding space is provided for the folding of the tab 51, so as to avoid damage to the tab 51 caused by folding.

[0078] As shown in Figure 3 and Figure 5 In some embodiments of the present application, the folding plate 42 is integrally formed with the fixing plate 41, and a gap 43 extending along the folding line is formed between the side of the folding plate 42 close to the fixing plate 41 and the support portion 412. Specifically, the gap 43 is formed between the side of the first plate body 421 of the folding plate 42 close to the fixing plate 41 and the support portion 412.

[0079] Optionally, the folding plate 42 and the fixing plate 41 are integrally formed plastic parts. The gap 43 is formed between the folding connection end of the folding plate 42 and the support portion 412, that is, the thickness of the folding plate 42 corresponding to the position of the gap 43 is thinned, so as to facilitate the folding of the folding plate 42 and enable it to be well buckled to the fixing plate 41.

[0080] As a specific example, asFigure 6 As shown in the figure, in the case where the folding plate 42 is buckled to the fixed plate 41, the width of the notch 43 is w1, the thickness of the part of the folding plate 42 close to the notch 43 is t1, the thickness of the folding plate 42 corresponding to the position of the notch 43 is t2, t1≥1mm, 0.4≤t2 / t1≤0.6, 0.2mm≤w1≤0.5mm. 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 easy to break; if the value of t2 / t1 is too large or the value of w1 is too small, the folding plate 42 is not easy to fold and is easy to be buckled.

[0081] As Figure 1 As shown in the figure, in some embodiments of the present application, the boss 11 is provided with a reinforcing rib 113, and the reinforcing rib 113 extends from one protrusion to another protrusion. It can be understood that one part of the reinforcing rib 113 is connected to one protrusion, and the other part is connected to another protrusion. The reinforcing rib 113 is connected to at least two adjacent protrusions to locally reinforce the plurality of protrusions and improve the overall impact resistance of the boss 11.

[0082] Optionally, the reinforcing rib 113 is arranged to extend along the length direction of the cover plate body 1. The main stress direction of the protrusion is consistent with the stacking direction of the plurality of protrusions. The reinforcing rib 113 extends from one protrusion to another protrusion and along the length direction of the cover plate body 1, which is beneficial to increase the structural strength of the protrusion and beneficial to disperse the stress of the protrusion.

[0083] The reinforcing rib 113 can be protruded on the first side of the cover plate body 1, i.e. on the same side of the cover plate body 1 as the boss 11, or on the second side of the cover plate body 1. When the reinforcing rib 113 is protruded on the first side of the cover plate body 1, the reinforcing rib 113 and the boss 11 can be formed together by stamping, which simplifies the process.

[0084] As Figure 1 As shown in the figure, in a specific embodiment, the plurality of protrusions includes a first protrusion 111 and a second protrusion 112. The second protrusion 112 is protruded on the upper surface of the first protrusion 111, the upper surface of the first protrusion 111 is adapted to be supported and connected with the box of the battery pack, and the exhaust hole is arranged on the second protrusion 112. The reinforcing rib 113 connecting the first protrusion 111 and the second protrusion 112 extends along the length direction from the upper surface of the second protrusion 112 to the upper surface of the first protrusion 111.

[0085] It can be understood that the protruding direction of the reinforcing rib 113 is consistent with the protruding direction of the boss 11, and the reinforcing rib 113 extends along the length direction of the cover plate body 1. The second protrusion 112 is protruded on the upper surface of the first protrusion 111, one part of the reinforcing rib 113 is connected to the upper surface of the first protrusion 111, and the other part is connected to the upper surface of the second protrusion 112.

[0086] Wherein, since the boss 11 is a structure bent along the length direction of the cover plate body 1, when it is impacted, it is easy to be bent and deformed. The extending direction of the reinforcing ribs 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.

[0087] As shown in FIG. 1, the second protruding part 112 has a top wall and a first side wall and a second side wall oppositely arranged along the length direction of the cover plate body 1. The first side wall and the second side wall are both connected to the top wall and the first protruding part 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 direction of the cover plate body 1 and are sequentially connected to the top wall, the first side wall and the first protruding part. The second reinforcing ribs extend along the length direction and are sequentially connected to the top wall, the second side wall and the first protruding part. The plurality of first reinforcing ribs are arranged at intervals in the width direction of the cover plate body 1, and the plurality of second reinforcing ribs are arranged at intervals in the width direction of the cover plate body 1. The plurality of first reinforcing ribs and the plurality of second reinforcing ribs are oppositely arranged one by one in the length direction of the cover plate body 1. Figure 2 As can be understood, the upper surface of the second protruding part 112 is formed on the top wall, and the exhaust hole penetrates the top wall. The plurality of first reinforcing ribs and the plurality of second reinforcing ribs are arranged at intervals in the length direction, and the exhaust hole is located between the plurality of first reinforcing ribs and the plurality of second reinforcing ribs. The first side and the second side of the second protruding part 112 are the main stress areas thereof, and the first side is structurally reinforced by the plurality of first reinforcing ribs, and the second side is structurally reinforced by the plurality of second reinforcing ribs, so as to avoid deformation and increase of structural stress of the second protruding part 112 when the boss 11 is impacted, thereby causing abnormal cracking of the explosion-proof valve 3.

[0088] Wherein, the plurality of first reinforcing ribs and the plurality of second reinforcing ribs are oppositely arranged one by one in the length direction of the cover plate body 1, which can form an exhaust passage on the upper surface of the second protruding part 112 extending along the length direction of the cover plate body 1, and the gas discharged from the explosion-proof valve 3 can flow along the exhaust passage, which is beneficial to improve the exhaust efficiency. Alternatively, the plurality of first reinforcing ribs and the plurality of second reinforcing ribs are symmetrically arranged with respect to each other in the length direction of the cover plate body 1.

[0089] As shown in FIG. 1, as a specific example, the number of the first reinforcing ribs and the second reinforcing ribs is three, so that two exhaust passages extending along the length direction of the cover plate body 1 are formed on the second protruding part 112. When a plurality of battery cells are arranged along the width direction of the cover plate body 1, the first reinforcing ribs and the second reinforcing ribs between adjacent two battery cells also form exhaust passages.

[0090] Figure 1

[0091] ​​It should be noted that the plurality of first reinforcing ribs can be of different lengths, and the plurality of second reinforcing ribs can be of different lengths. The plurality of first reinforcing ribs and the plurality of second reinforcing ribs can be arranged according to the shape of the exhaust hole, for example, each first reinforcing rib and each second reinforcing rib are equidistant from the edge of the exhaust hole, so that the first reinforcing rib and the second reinforcing rib have a longer length, thereby forming an effective exhaust passage.

[0092] As shown in Figure 1 , optionally, the plurality of first reinforcing ribs and the plurality of second reinforcing ribs are arranged at intervals in the length direction of the cover plate body 1.

[0093] It can be understood that in the length direction of the cover plate body 1, there is a certain distance between the overall structure of the plurality of first reinforcing ribs and the overall structure of the plurality of second reinforcing ribs, and the exhaust hole is located therebetween. When the plurality of battery cells are arranged along the width direction of the cover plate body 1, the exhaust passages on the second protrusions 112 of the adjacent two battery cells can be connected to each other in the width direction, which is beneficial to improve the exhaust efficiency.

[0094] The embodiment of the present application also provides a battery cell, which comprises a battery cell shell, a pole group 5, and a battery cell cover plate provided by any one of the above embodiments. The battery cell shell is provided with an opening, and the battery cell cover plate is arranged in the opening and cooperates with the battery cell shell to form a containing cavity. The pole group 5 is arranged in the containing cavity, and the tab 51 of the pole group 5 is connected with the pole 21.

[0095] When assembling the battery cell, the pole 21 of the pole group 5 and the battery cell cover plate is welded first, and the battery cell cover plate is assembled at one end of the pole group 5, then the pole group 5 is assembled into the battery cell shell, and the cover plate body 1 is welded with the battery cell shell. Before entering the shell, the outer side of the pole group 5 is usually wrapped with an insulating film, so as to insulate and isolate the pole group 5 and the battery cell shell.

[0096] Further, as shown in Figure 6 , in the thickness direction of the cover plate body 1, the welding part of the tab 51 is located between the folded plate 42 and the connecting piece 22, the thickness of the welding part of the tab 51 is t, the distance between the second plate body 422 of the folded plate 42 and the extension part 222 of the connecting piece 22 is g2, and 0.2mm≤g2-t≤0.5mm. If the value of g2-t is too small, the folded plate 42 is easy to crush the tab 51; if the value of g2-t is too large, the fixing effect of the folded plate 42 on the tab 51 is not good.

[0097] Further, in the case that the folded plate 42 is buckled on the fixed plate 41, in the thickness direction of the cover plate body 1, the distance between the first plate and the pole 21 is g1, and 0.2mm≤g1≤0.5mm. In the case that the folded plate 42 has a third plate body 423, the distance between the third plate body 423 and the fixed plate 41 is g3, and 0.2mm≤g3≤0.5mm.

[0098] As Figure 7 and Figure 8 shown, in some embodiments of the present application, the pole group 5 corresponds to the position of the second plate body 422 of the folded plate 42 and has two pole ears 51. The two pole ears 51 are arranged in the width direction of the cover plate body 1 and symmetrically distributed on both sides of the second plate body 422. The size of the second plate body 422 in the width direction of the cover plate body 1 is smaller than the interval of the folded positions of the two pole ears 51.

[0099] Specifically, one end of the extension part 222 away from the base part 221 is provided with two welding parts arranged at intervals in the width direction of the cover plate body 1, and the two welding parts are respectively welded with the two pole ears 51 of the pole group 5 to reduce the influence of welding heat on the pole ears 51. The two pole ears 51 are respectively folded from both sides of the folded plate 42 between the folded plate 42 and the extension part 222, and are respectively welded with the two welding parts of the extension part 222. In order to avoid interference caused by the folding of the pole ears 51 due to the width of the folded plate 42, the length direction of the folded plate 42 is inwardly recessed by a certain width relative to the folding position of the pole ears 51 on both sides.

[0100] As Figure 8 shown, the interval of the folded positions of the two pole ears 51 is G, the size of the second plate body 422 in the width direction of the cover plate body 1 is W2, and the inwardly recessed width of the length direction of the folded plate 42 relative to the folding position of the pole ears 51 on both sides is (G-W2) / 2. Optionally, 2mm≤(G-W2) / 2≤5mm. If (G-W2) / 2 is too small, the folded pole ears 51 will interfere with the second plate body 422; if (G-W2) / 2 is too large, the width of the second plate body 422 is too narrow, which affects the fixing effect of the pole ears 51.

[0101] Specifically, as Figure 9 shown, the pole group 5 includes a first assembly and a second assembly independent of each other, and each of the first assembly and the second assembly has a pole ear 51. The extension part 222 of the connecting sheet 22 has two welding parts arranged at intervals in the width direction of the cover plate body 1, the pole ear 51 of the first assembly is welded with one of the welding parts, and the pole ear 51 of the second assembly is welded with the other welding part. In this way, the welding heat of one of the pole ears 51 and the welding part can be avoided from affecting the welding of the other pole ear 51, and the welding yield of the pole ear 51 can be improved.

[0102] As Figure 9 shown, during welding, the first assembly and the second assembly can be placed on both sides of the length direction of the cover plate body 1, and the pole ears 51 of the first assembly and the second assembly are opposite. After the pole ears 51 of the two assemblies are welded with the pole column 21, the first assembly and the second assembly are turned to a merged state, and the pole ear 51 ends of the two assemblies are opposite to the cover plate body 1, that is, the assembly of the pole group 5 and the cover plate body 1 is completed, see Figure 10 .

[0103] As shown in FIG. 1, the connection end face 50 of the pole group 5 is provided with a convex bump 52. The tab 51 is connected to the connection end face 50 and located beside the convex bump 52, and the convex bump 52 is accommodated in the sink 40 of the insulating piece 4. In this way, the internal space of the battery cell can be fully utilized, the volume of the pole group 5 is increased, and thus the capacity of the battery cell is increased. The convex bump 11 formed by the bending part of the cover plate body 1 can increase the internal space of the convex bump 11, increase the volume of the convex bump 52, and thus increase the capacity of the battery cell. Figure 7 As shown in FIG. 1, the connection end face 50 of the pole group 5 is provided with a convex bump 52. The tab 51 is connected to the connection end face 50 and located beside the convex bump 52, and the convex bump 52 is accommodated in the sink 40 of the insulating piece 4. In this way, the internal space of the battery cell can be fully utilized, the volume of the pole group 5 is increased, and thus the capacity of the battery cell is increased. The convex bump 11 formed by the bending part of the cover plate body 1 can increase the internal space of the convex bump 11, increase the volume of the convex bump 52, and thus increase the capacity of the battery cell.

[0104] It can be understood that the pole group 5 is stacked by a plurality of electrode sheets in the width direction of the cover plate body 1, and each electrode sheet has a protruding part corresponding to one end of the tab 51. The protruding parts of the plurality of electrode sheets are stacked to form the convex bump 52.

[0105] As shown in FIG. 1, the connection end face 50 of the pole group 5 is provided with a convex bump 52. The tab 51 is connected to the connection end face 50 and located beside the convex bump 52, and the convex bump 52 is accommodated in the sink 40 of the insulating piece 4. In this way, the internal space of the battery cell can be fully utilized, the volume of the pole group 5 is increased, and thus the capacity of the battery cell is increased. The convex bump 11 formed by the bending part of the cover plate body 1 can increase the internal space of the convex bump 11, increase the volume of the convex bump 52, and thus increase the capacity of the battery cell. Figure 7 As shown in FIG. 1, the connection end face 50 of the pole group 5 is provided with a convex bump 52. The tab 51 is connected to the connection end face 50 and located beside the convex bump 52, and the convex bump 52 is accommodated in the sink 40 of the insulating piece 4. In this way, the internal space of the battery cell can be fully utilized, the volume of the pole group 5 is increased, and thus the capacity of the battery cell is increased. The convex bump 11 formed by the bending part of the cover plate body 1 can increase the internal space of the convex bump 11, increase the volume of the convex bump 52, and thus increase the capacity of the battery cell.

[0106] In some embodiments, the groove structure includes at least one first groove 521 extending along the length direction of the connection end face 50 and penetrating through opposite sides of the convex bump 52. In this way, it is beneficial for the gas in the battery cell corresponding to the two sides in the width direction of the cover plate body 1 to enter the first groove 521.

[0107] In some embodiments, the groove structure includes at least one second groove 522 extending along the width direction of the connection end face 50 and penetrating through opposite sides of the convex bump 52. In this way, it is beneficial for the gas in the battery cell corresponding to the two sides in the length direction of the cover plate body 1 to enter the second groove 522.

[0108] In some embodiments, the groove structure includes at least one first groove 521 extending along the length direction of the connection end face 50 and penetrating through opposite sides of the convex bump 52, and at least one second groove 522 extending along the width direction of the connection end face 50 and penetrating through opposite sides of the convex bump 52. In this way, it is beneficial for the gas around the battery cell to enter the groove structure, and the exhaust efficiency is improved.

[0109] As shown in FIG. 1, the connection end face 50 of the pole group 5 is provided with a convex bump 52. The tab 51 is connected to the connection end face 50 and located beside the convex bump 52, and the convex bump 52 is accommodated in the sink 40 of the insulating piece 4. In this way, the internal space of the battery cell can be fully utilized, the volume of the pole group 5 is increased, and thus the capacity of the battery cell is increased. The convex bump 11 formed by the bending part of the cover plate body 1 can increase the internal space of the convex bump 11, increase the volume of the convex bump 52, and thus increase the capacity of the battery cell. Figure 7As shown, in some embodiments of the present application, the convex bump 52 has a top surface 5201 and a side surface 5202, and the top surface 5201 is connected to the connecting end surface 50 at both ends in the length direction of the cover plate body 1 through a side surface 5202, forming a trapezoidal convex bump 52. The first groove 521 extends from one side surface 5202 away from one end of the top surface 5201 to the other side surface 5202 away from the other end of the top surface 5201.

[0110] As can be understood, the side surface 5202 is arranged obliquely relative to the connecting end surface 50, and the side surface 5202 is arranged at an obtuse angle with the connecting end surface 50. The first groove 521 extends from one end of the side surface 5202 connected to the connecting end surface 50 to the other end of the side surface 5202 connected to the connecting end surface 50, so that the air flow flowing along the connecting end surface 50 smoothly enters the first groove 521.

[0111] As shown in FIGS. Figure 2 and Figure 4 As shown, in some embodiments of the present application, the sink groove 40 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 piece 4 facing the pole group 5 corresponding to the position of the first convex portion 111, and the second groove portion 402 is recessed in the first groove portion 401 and arranged opposite the second convex portion 112. The convex bump 52 extends into the second groove portion 402 and is limited in position in the length direction of the cover plate body 1 with the second groove portion 402.

[0112] As can be understood, the sink groove 40 is a stepped groove composed of the first groove portion 401 and the second groove portion 402, and the deeper second groove portion 402 is used for limiting the position of the convex bump 52 of the pole group 5, which can play a role in assembly positioning during the assembly of the battery cell cover plate and the pole group 5, and can prevent the pole group 5 from moving along the length direction of the cover plate body 1 and straining the tab 51 when the battery cell is impacted by external force. The space formed between the connecting end surface 50 of the pole group 5 and the first groove portion 401 can be used to accommodate the tab 51, and the extension portion 222 of the connecting piece 22 is located in the first groove portion 401.

[0113] The length direction of the cover plate body is defined as the dimension L, and the width direction of the cover plate body is defined as the dimension W. For some parameter value ranges defined in embodiments of the present application, a DOE test design is performed on the cover plate body with 150mm≤L≤300mm and 25mm≤W≤75mm. Taking a battery cell cover plate with two folding plates as an example, folding tests are performed on the folding plates of multiple battery cell cover plates to determine whether the strength at the notch meets the use requirements. After the battery cell cover plate is assembled with the pole group, the fixing effect of the insulating piece on the tab is detected by X-ray, whether the folding plate crushes the tab, and the distance between the two sides of the folding plate and the tab. The experimental results are shown in Table 1. The units of t1, t2, w1, g2, G, W2 and t in Table 1 are mm.

[0114] Table 1: Experimental data

[0115] The experimental results in Table 1 show that when the cover plate body meets the design requirements of the above embodiments, referring to cases 1-9 in Table 1, the strength of the insulating part at the notch is sufficient, the tab is fixed well and there is no tab pressure injury, and the folding plate does not interfere with the tab. On the contrary, referring to cases 10-12 in Table 1, the strength of the notch of the folding plate is insufficient and is prone to breakage; or after assembly with the tab group, there is a risk of damaging the tab or interference, and the safety is reduced.

[0116] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell cover plate, characterized in that, include: The cover plate body is provided with a boss, the boss comprising a plurality of protrusions stacked sequentially along the thickness direction of the cover plate body; An insulating component includes a fixed plate and a folding plate. The fixed plate is located on the side of the cover plate body away from the boss and has a support portion protruding away from the cover plate body. The folding plate is folded and connected to the support portion, so that the folding plate can be fastened or opened relative to the fixed plate. The pole is inserted through the cover plate body and the fixing plate along the thickness direction of the cover plate body; When the folding plate is fastened to the fixing plate, the folding plate covers the pole post, and both the support 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, Also includes: The explosion-proof valve has an exhaust hole that penetrates the cover plate body on the topmost protrusion. The explosion-proof valve is installed on the topmost protrusion and is opposite to the exhaust hole.

3. The cell cover plate according to claim 2, characterized in that, The number of the support part, the folding plate and the pole post are all two, and the two support parts, the two folding plates and the two pole posts are arranged in a one-to-one correspondence; the boss is located between the two pole posts and the vent is located between the two folding plates.

4. The cell cover plate according to claim 1, characterized in that, The cover plate body has a recess on the side near the insulating member corresponding to the protrusion, and the fixing plate cooperates with the recess. 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 insulating member has a recess on the side away from the cover plate body corresponding to the groove.

5. The cell cover plate according to claim 4, characterized in that, Also includes: A connecting piece is located between the fixing plate and the folding plate. The connecting piece includes a 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 fixing plate, the folding plate covers the base portion and the extension portion.

6. The cell cover plate according to claim 5, characterized in that, The folding plate has a first plate and a second plate, the first plate being folded and connected to the support portion; when the folding plate is fastened to the fixing plate, the first plate covers the base portion, the second plate is located in the groove and covers the extension portion; in the width direction of the cover plate body, the width of the second plate is smaller than the width of the first plate.

7. The cell cover plate according to claim 1, characterized in that, The folding plate and the fixed plate are integrally formed, and a notch extending along the folding line is formed between the side of the folding plate near the fixed plate and the support portion.

8. The cell cover plate according to any one of claims 1 to 7, characterized in that, The cover plate body includes a base plate portion and a bending portion. The bending portion is connected to the base plate portion at both ends in the length direction of the cover plate body. The bending 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.

9. 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 8, 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 electrode tabs of the electrode assembly are connected to the electrode post.

10. The battery cell according to claim 9, characterized in that, In the thickness direction, the welding part of the electrode tab is located between the folded plate and the connecting piece of the cell cover plate, the thickness of the welding part is t, and the distance between the second plate of the folded plate and the extension of the connecting piece is g2, 0.2mm≤g2-t≤0.5mm; And / or, the pole group has two pole ears corresponding to the position of the second plate of the folding plate, the two pole ears are arranged in the width direction of the cover plate body and symmetrically distributed on both sides of the second plate body, the distance between the closed positions of the two pole ears is G, and the dimension of the second plate body in the width direction is W2, 2mm≤(G-W2) / 2≤5mm.

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