Terminal post, cover plate assembly and battery

Abstract

The present application relates to the technical field of batteries. Disclosed are a terminal post, a cover plate assembly and a battery. The terminal post comprises: a plate body, which comprises an aluminum layer and a copper layer, wherein the copper layer is annular and is connected to at least part of a first side face of the aluminum layer; and a post body, which is connected to a first side of the plate body, wherein at least part of the copper layer surrounds and is connected to the peripheral side of the post body, at least part of the post body being a copper post portion, which covers the outer surface of the post body and is fixedly connected to the copper layer; the post body is adapted to pass through a first through hole on a cover plate body, the area on the surface of the cover plate body occupied by the first through hole being S0, the area enclosed by the projection of the outer contour of the copper layer on the surface of the cover plate body being S1, and the projected area of the aluminum layer on the surface of the cover plate body being S2, where S0<S1≤S2. At least part of a copper-aluminum bonding surface on the terminal post being located at the outer periphery of the contour of the first through hole prevents delamination in the bonding surface between the copper layer and the aluminum layer due to tensile stress, thereby preventing the terminal post from breaking at the copper-aluminum bonding surface.

Description

Pole, cover plate assembly and battery

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202411125942.2, filed on August 16, 2024, and entitled "Pole, cover plate assembly and battery", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to a pole, a cover plate assembly and a battery. BACKGROUND

[0004] With the continuous development of the battery industry, people's requirements for the safety of batteries are becoming higher and higher. As a key component connecting the inside and outside of the battery, the performance of the pole has an important influence on the performance of the entire battery. Among them, the negative pole is mostly in the form of copper-aluminum composite to improve its performance. The copper-aluminum composite pole in the prior art is mostly realized by friction welding of the copper layer and the aluminum layer to form a bonding plane between the copper layer and the aluminum layer.

[0005] However, the bonding plane in the form of a plane has low strength and poor reliability. During long-term use of the battery, after experiencing long-term vibration, impact and other working conditions, under the interaction of various parts, the pole is easily broken from the bonding plane, resulting in battery disconnection, and increasing the cost of manpower and material resources for after-sales maintenance. SUMMARY

[0006] Therefore, the present application provides a pole, a cover plate assembly and a battery to solve the problem that the composite pole is easily broken from the bonding plane.

[0007] In a first aspect, the present application provides a pole, comprising: a plate body comprising an aluminum layer and a copper layer, the copper layer being annular and connected to at least part of the first side of the aluminum layer; a column body connected to the first side of the plate body, at least part of the copper layer being connected to the outer circumferential side of the column body, at least part of the column body being the copper column part, the copper column part covering the outer surface of the column body and being fixedly connected with the copper layer; the column body is adapted to be arranged in a first through hole on the cover plate body, the area occupied by the first through hole on the surface of the cover plate body is S0, the area surrounded by the projection of the outer contour of the copper layer on the surface of the cover plate body is S1, and the projection area of the aluminum layer on the surface of the cover plate body is S2, wherein S0 < S1 ≤ S2.

[0008] Beneficial effects: By setting the plate body has connected aluminum layer and copper layer, the copper column part on the column body covers the outer surface of the column body and is fixedly connected with the copper layer, so that the column body is pure copper in appearance, but actually is copper-aluminum composite material, the plate body is copper-aluminum composite material, that is, the pole column is copper-aluminum composite material as a whole, which can realize electrical connection with the pole lug and reduce the amount of copper and cost. At the same time, the area S1 surrounded by the projection of the outer contour of the copper layer on the surface of the cover plate body is greater than the area S0 of the first through hole on the cover plate body, and is less than or equal to the projection area S2 of the aluminum layer on the surface of the cover plate body, so that when the pole column is arranged in the first through hole of the cover plate body, at least a part of the copper-aluminum bonding surface is located at the periphery of the first through hole contour, and the cover plate body supports the copper layer on the plate body. Even in the case that the column body is pulled by the rebound force of the sealing element arranged on the column body, the copper layer and the aluminum layer will not be separated due to tensile stress, thereby effectively preventing the composite pole column from being broken at the bonding surface, improving the quality of the pole column, and ensuring the quality of the battery.

[0009] In an alternative embodiment, the copper layer is annular, the column body includes an aluminum column part and a copper column part, the aluminum column part is protruded from the aluminum layer in a direction away from the aluminum layer by a partial area on the first side surface of the aluminum layer, the copper column part has a recessed part opening towards the plate body, the recessed part is connected with the aluminum column part in a matching manner to wrap the aluminum column part, and the opening end of the copper column part is connected with the inner ring of the copper layer. Alternatively, the column body is a copper column part, and one end of the copper column part close to the plate body is connected with the copper layer.

[0010] Beneficial effects: By setting the column body to include an aluminum column part integrally connected with the aluminum layer and a copper column part integrally connected with the copper layer, the recessed part on the copper column part is connected with the aluminum column part in a matching manner, and the opening end of the recessed part is connected with the inner ring of the copper layer, so as to wrap the aluminum column part with the copper column part, making the column body appear to be pure copper in appearance, but actually be copper-aluminum composite material. Moreover, the aluminum column part protrudes from the surface of the aluminum layer, so that the copper-aluminum bonding surface between the copper material and the aluminum material on the cross section of the pole column in the plane of the center line is a continuous surface in the shape of inverted "J", which has a larger area than the traditional flat bonding surface, has higher composite strength, and uses less copper.

[0011] In an alternative embodiment, the thickness of the plate body is a, and the minimum thickness of the aluminum layer is b, which satisfies: 1 / 3≤b / a<1.

[0012] Beneficial effects: both the thickness of the aluminum layer and the copper layer can be guaranteed, the maximum area of the copper layer on the cover plate body is projected at least partially on the outer periphery of the contour line of the first through hole, so that the cover plate body can support the copper layer, avoid the copper-aluminum joint surface from being disconnected due to tensile stress, and improve the structural strength of the pole.

[0013] In an alternative embodiment, the thickness a of the plate body is in the range of 2mm≤a≤5mm; and / or, the minimum thickness b of the aluminum layer is in the range of b≥1.5mm.

[0014] Beneficial effects: by setting the thickness a of the plate body in the range of 2mm to 5mm, the plate body can be prevented from being welded through during welding with the aluminum tab, and the welding heat can be prevented from being transmitted to the first insulating piece in large quantities through the plate body, so as to prevent the first insulating piece from melting, guarantee the resistance value of the first insulating piece from fluctuating, ensure the consistency of the positive and negative electrode edge voltage of the battery, avoid the electrolyte corrosion in the battery, and prevent the plate body from being too thick to cause the pole to be too heavy, thereby reducing the cost and improving the volume energy density of the battery. By setting the minimum thickness b of the aluminum layer to be greater than or equal to 1.5mm, the maximum penetration of the aluminum tab and the pole during welding can be prevented from penetrating the aluminum layer, and the welding heat transmitted to the first insulating piece can be prevented from exceeding the melting point of the first insulating piece, so as to prevent the resistance value of the first insulating piece from fluctuating, ensure the consistency of the positive and negative electrode edge voltage of the battery, and improve the electrical performance and safety performance of the battery.

[0015] In an alternative embodiment, the pole is processed from a copper-aluminum composite plate, and the plate body and the column body are integrally formed.

[0016] Beneficial effects: the copper-aluminum composite plate is a molding material, the copper material and the aluminum material in the copper-aluminum composite plate are combined together and cannot be separated, the composite stability is good, and the copper-aluminum composite plate has the advantages of high strength, durability, cost performance, etc. The entire pole is processed from the copper-aluminum composite plate, and the integrally formed processing process is simple, which avoids the traditional friction welding process of the copper layer and the aluminum layer. The copper-aluminum composite plate is simple to process, has high material utilization rate, stable structure, and reduced cost. In addition, the contact area of the copper-aluminum composite joint surface is large, the overcurrent capacity of the pole is enhanced, and the pole will not be melted in the case of large current in the pole, thereby avoiding the battery out of control and improving the safety.

[0017] In an alternative embodiment, the column is a cylindrical column or an elliptical cylindrical column or a polygonal column; and / or, the column comprises a column body connected to the plate body and a boss connected to the column body at an end away from the plate body, a center line of the boss coincides with a center line of the column, and a cross-sectional area of the boss is smaller than a cross-sectional area of the column body.

[0018] Beneficial effects: simple processing, easy molding and good stability. By constructing a boss at an end of the column away from the plate body, the center line of the boss coincides with the center line of the column, and the cross-sectional area of the boss is smaller than the cross-sectional area of the column body. The boss is suitable for being inserted into the fourth through hole on the bottom plate, and the column body is suitable for abutting against the bottom surface of the mounting groove on the bottom plate, so as to realize mutual limiting of the column and the bottom plate and facilitate the stability of assembly.

[0019] In a second aspect, the application further provides a cover plate assembly, comprising: a cover plate body provided with a first through hole; a first insulating piece arranged on one side of the cover plate body, the first insulating piece being provided with a second through hole; a second insulating piece arranged on a side of the cover plate body away from the first insulating piece, the second insulating piece being provided with a third through hole; a bottom plate arranged on a side of the second insulating piece away from the cover plate body, the bottom plate being provided with a fourth through hole; the pole column described above, a column of the pole column being arranged in the fourth through hole in sequence through the second through hole, the first through hole and the third through hole, and a plate body of the pole column abutting against a side of the first insulating piece away from the cover plate body; and a sealing piece arranged between the column and the cover plate body, an inner side of the sealing piece abutting against an outer peripheral surface of the column and an outer side of the sealing piece abutting against an inner wall of the first through hole. Because the cover plate assembly comprises the pole column, it has the same effects as the pole column, which will not be described here.

[0020] In an alternative embodiment, the bottom plate is provided with a mounting groove, the fourth through hole is located in the mounting groove, a cross-sectional area of the fourth through hole is smaller than a cross-sectional area of a column body of the pole column, the column body abuts against the mounting groove, and a boss of the column is arranged in the fourth through hole; and / or, the first insulating piece and the second insulating piece are made of plastic; and / or, the sealing piece is made of rubber.

[0021] Beneficial effects: By setting the mounting groove on the bottom plate and opening the fourth through hole in the mounting groove, when the pole column cooperates with the bottom plate, because the cross-sectional area of the fourth through hole is smaller than the size of the column body, the column body cannot penetrate into the fourth through hole, the end face of the column body close to the boss side abuts against the bottom surface of the mounting groove, realizing the mutual limiting of the bottom plate and the column body along the axial direction of the pole column, preventing the bottom plate from further displacing towards the direction close to the cover plate body, and at the same time, the boss of the column is arranged in the fourth through hole, the fourth through hole limits the boss in the radial direction, thereby realizing the relative fixation of the bottom plate and the column, convenient assembly and good stability. The plastic has good insulation, stable performance. The rubber has good elasticity, excellent heat resistance and good electrical insulation performance, and the rubber is common and easy to obtain, and the cost is low.

[0022] In an alternative embodiment, the boss is welded to the bottom plate.

[0023] Beneficial effects: By welding the boss to the bottom plate, the fixed connection of the pole column and the bottom plate is realized, the traditional riveting process between the pole column and the bottom plate is cancelled, the process cost of the cover plate assembly is reduced under the premise of ensuring the structural strength.

[0024] In a third aspect, the application also provides a battery, comprising: a shell having an open end; the cover plate assembly described above is arranged at the open end of the shell to close the shell; a pole group is arranged inside the shell, the end of the pole group has a pole lug, and the pole lug is electrically connected to the bottom plate in the cover plate assembly. Because the battery includes the cover plate assembly, it has the same effects as the cover plate assembly, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0026] Fig. 1 is a structural schematic view of a first pole column of an embodiment of the present application;

[0027] Fig. 2 is a sectional view of the pole column shown in Fig. 1;

[0028] Fig. 3 is a structural schematic view of another perspective view of the pole column shown in Fig. 1;

[0029] Fig. 4 is a bottom view of the pole column shown in Fig. 1;

[0030] Fig. 5 is a side view of the pole column shown in Fig. 1;

[0031] Fig. 6 is a sectional view of a second pole column of an embodiment of the present application;

[0032] Fig. 7 is a sectional view of a third pole post according to an embodiment of the present application;

[0033] Fig. 8 is a sectional view of a fourth pole post according to an embodiment of the present application;

[0034] Fig. 9 is a structural schematic diagram of a fifth pole post according to an embodiment of the present application;

[0035] Fig. 10 is a sectional view of the pole post shown in Fig. 9;

[0036] Fig. 11 is a sectional view of a sixth pole post according to an embodiment of the present application;

[0037] Fig. 12 is a structural schematic diagram of a cover plate assembly according to an embodiment of the present application;

[0038] Fig. 13 is an exploded schematic diagram of the cover plate assembly shown in Fig. 12;

[0039] Fig. 14 is a structural schematic diagram of the cover plate assembly shown in Fig. 12 from a bottom perspective;

[0040] Fig. 15 is an exploded schematic diagram of the cover plate assembly from the bottom perspective shown in Fig. 14;

[0041] Fig. 16 is a sectional view of the cover plate assembly shown in Fig. 12;

[0042] Fig. 17 is a partial enlarged schematic diagram of A in the cover plate assembly shown in Fig. 16;

[0043] Fig. 18 is a side view of the cover plate assembly shown in Fig. 12;

[0044] Fig. 19 is a projection view of the cover plate assembly shown in Fig. 18 along direction B;

[0045] Fig. 20 is a schematic diagram of the overlapping area of the projection of the copper layer on the cover plate body and the surface of the cover plate body shown in Fig. 19;

[0046] Fig. 21 is a structural schematic diagram of a battery according to an embodiment of the present application.

[0047] Explanation of reference signs: 1, pole post; 110, plate body; 111, aluminum layer; 112, copper layer; 113, first bonding surface; 120, post body; 121, aluminum post part; 122, copper post part; 123, recessed part; 124, second bonding surface; 125, boss; 126, post body proper; 200, cover plate assembly; 2, cover plate body; 201, first through hole; 202, first recess; 210, copper layer maximum area projection line; 220, plate body outline projection line; 230, through hole outline line; 3, first insulating member; 301, second through hole; 302, second recess; 4, second insulating member; 401, third through hole; 5, bottom plate; 501, fourth through hole; 502, mounting groove; 503, third recess; 6, sealing member; 7, housing; 8, pole group; 801, pole lug; 9, weld. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0049] In the related art, the composite pole post is mostly made of copper and aluminum by friction welding, which has low material utilization, high processing cost, great processing difficulty, and poor reliability of the composite surface. On the one hand, when the battery is subjected to large-rate charging and discharging, a large amount of heat is generated, which causes the pole post to be melted and broken from the bonding surface, and even a fire is generated, which leads to the loss of control of the entire battery, and further affects the entire package and the vehicle. On the other hand, the composite surface has low strength, and when the power battery is used normally on the vehicle, the vehicle is subjected to long-term vibration and impact during driving, which easily causes the composite surface to be broken, resulting in a short circuit and increasing the labor and material costs of after-sales maintenance.

[0050] The embodiments of the present application will be described below with reference to FIGS. 1 to 21.

[0051] According to the embodiments of the present application, in one aspect, a pole is provided, as shown in FIGS. 1-11, the pole comprising: a plate body 110 and a column body 120. The plate body 110 comprises an aluminum layer 111 and a copper layer 112, the copper layer 112 being connected to at least a part of a first side of the aluminum layer 111; the column body 120 being connected to a first side of the plate body 110, at least a part of the copper layer 112 being wrapped around an outer circumferential side of the column body 120, at least a part of the column body 120 being a copper column part 122, the copper column part 122 covering an outer surface of the column body 120 and being fixedly connected to the copper layer 112; the column body 120 being adapted to be arranged in a first through hole 201 of a cover plate body 2, the first through hole 201 occupying an area S0 on a surface of the cover plate body 2, a projection of an outer contour of the copper layer 112 on the surface of the cover plate body 2 forming an area S1, and a projection area of the aluminum layer 111 on the surface of the cover plate body 2 being S2, wherein S0 < S1 ≤ S2.

[0052] The dividing line between the plate body 110 and the column body 120 is shown by the dashed line in FIGS. 2, 6-8, 10-11; the plate body 110 is plate-shaped and has two opposite large-area surfaces, the first side of the plate body 110 referring to a side on which one of the two surfaces is located; the first side of the aluminum layer 111 and the first side of the plate body 110 are in the same direction, both being directed toward the column body 120; the axis of the column body 120 is perpendicular to the large surface of the plate body 110, the outer circumferential side of the column body 120 referring to a surface on the column body 120 which is away from the axis of the column body 120; at least a part of the copper layer 112 is wrapped around the outer circumferential side of the column body 120, the outer contour of the copper layer 112 referring to a contour on the copper layer 112 which is away from the outer circumferential surface of the column body 120 in a direction perpendicular to the axis of the column body 120; the outer surface of the column body 120 refers to a surface on the column body 120 other than an end surface connected to the plate body 110; the area occupied by the first through hole 201 on the surface of the cover plate body 2 refers to an opening area of the first through hole 201 on the cover plate body 2.

[0053] The pole post of the embodiment is provided with the plate body 110 having the connected aluminum layer 111 and copper layer 112, and the copper column part 122 on the post body 120 covers the outer surface of the post body 120 and is fixedly connected with the copper layer 112, so that the post body 120 is externally characterized by pure copper, and the plate body 110 is of copper-aluminum composite material, that is, the whole pole post 1 is of copper-aluminum composite material, which can realize electrical connection with the pole lug and reduce the amount of copper, weight and cost. Meanwhile, the area S1 surrounded by the projection of the outer contour of the copper layer 112 on the surface of the cover plate body 2 is greater than the area S0 of the first through hole 201 on the cover plate body 2 and less than or equal to the projection area S2 of the aluminum layer 111 on the surface of the cover plate body 2, so that when the pole post 1 is arranged in the first through hole 201 on the cover plate body 2, at least a part of the copper-aluminum joint surface is located at the periphery of the first through hole 201, and the cover plate body 2 supports the copper layer 112 on the plate body 110. Even if the post body 120 is pulled by the rebounding force of the sealing element 6 arranged on the post body 120, the copper layer 112 and the aluminum layer 111 will not be separated due to the tensile stress, so that the composite pole post is effectively prevented from being broken at the copper-aluminum joint surface, the quality of the pole post 1 is improved, and the quality of the battery is ensured. The copper-aluminum joint surface is the contact surface between the copper material and the aluminum material, and the first joint surface 113 is formed between the aluminum layer 111 and the copper layer 112 on the plate body 110. The periphery of the first through hole 201 refers to one side of the first through hole 201 away from the center thereof in the radial direction.

[0054] It should be noted that the pole post 1 is a negative pole post, the copper column part 122 on the pole post 1 faces the inner side of the battery and is used for welding with the negative pole lug of the copper material of the pole group, and the aluminum layer 111 on the pole post 1 faces the outer side of the battery and is used for welding with the aluminum tab (i.e., the conductive row), which has good conductivity, light weight and can reduce the amount of copper and cost. The projection refers to orthographic projection. Further in combination with FIGS. 18-20, the projection refers to the projection on the cover plate body 2 in the direction of arrow B in FIG. 18, that is, the projection in the direction perpendicular to the cover plate body 2. The projection of the outer contour of the copper layer 112 on the surface of the cover plate body 2 forms a copper layer maximum area projection line 210, and the area S1 surrounded by the projection of the outer contour of the copper layer 112 on the surface of the cover plate body 2 refers to the area of the region surrounded by the copper layer maximum area projection line 210. The projection of the aluminum layer 111 on the surface of the cover plate body 2 is the projection of the plate body 110 on the surface of the cover plate body 2, the edge of the projection is a plate body contour projection line 220, and the projection area S2 of the aluminum layer 111 on the surface of the cover plate body 2 refers to the area of the region surrounded by the plate body contour projection line 220. The area S0 of the first through hole 201 refers to the area of the region surrounded by a through hole contour line 230.

[0055] Optionally, further in combination with FIGS. 1-8, the outer contour of the copper layer 112 coincides with the outer contour of the aluminum layer 111, and the projected area S1 of the outer contour of the copper layer 112 on the surface of the cover plate body 2 satisfies the relationship S1=S2 with the projected area S2 of the aluminum layer 111 on the surface of the cover plate body 2. The outer contour of the copper layer 112 coincides with the outer contour of the aluminum layer 111, and the first bonding surface 113 on the plate body 110 reaches the maximum. Since the size of the copper-aluminum bonding surface has a great influence on the strength of the composite surface, the greater the contact area of copper and aluminum at the copper-aluminum bonding surface, the stronger the overcurrent capacity of the pole. In the case of passing a large current in the pole 1, the pole will not be melted, thereby avoiding the out-of-control of the battery. When the first bonding surface 113 on the plate body 110 reaches the maximum, i.e., the copper-aluminum bonding surface on the pole reaches the maximum, the strength of the bonding surface and the overcurrent capacity of the pole can be improved as much as possible. The greater the area of the copper layer 112, the greater the area of the first bonding surface 113. When the pole 1 is installed into the first through hole 201 on the cover plate body 2, the more copper-aluminum bonding surfaces are supported by the cover plate body 2, the better the support performance of the copper layer 112 can be improved, and the influence of the tensile stress generated by the sealing element 6 on the copper material is reduced, thereby improving the stability of the copper-aluminum bonding surface, avoiding the fracture of the pole from the bonding surface, and improving the safety. It should be noted that the tensile force generated by the sealing element 6 on the copper-aluminum bonding surface is opposite to the supporting force of the cover plate body 2 on the copper-aluminum bonding surface.

[0056] It can be understood that, as an alternative embodiment, further in combination with FIGS. 9-11, the size of the outer contour of the copper layer 112 is smaller than the size of the outer contour of the aluminum layer 111, and S0, S1 and S2 satisfy the formula: S0 < S1 < S2. Similarly, the projection of the maximum area of the copper layer on the cover plate body 2 is at least partially located on the periphery of the contour line of the first through hole 201, the projection line 210 of the maximum area of the copper layer exceeds the range of the through hole contour line 230, and the overlapping area of the projection of the copper layer on the cover plate body 2 and the surface of the cover plate body 2 (i.e., the shaded part in FIG. 20) is the overlapping area, and the area of the overlapping area is S, and S is greater than 0. It should be noted that the area of the surface of the plate body 110 other than the column 120 is a plane, that is, when the size of the outer contour of the copper layer 112 is smaller than the size of the outer contour of the aluminum layer 111, the copper layer 112 is embedded in the aluminum layer 111, and the copper layer 112 on the plate body 110 does not protrude from the surface of the aluminum layer 111, thereby ensuring the flatness of the surface of the plate body 110. On the basis of ensuring that the size of the outer contour of the copper layer 112 is greater than the size of the outer contour of the first through hole 201, by setting the size of the outer contour of the copper layer 112 to be smaller than the size of the outer contour of the aluminum layer 111, it is ensured that at least a part of the copper-aluminum combination surface is located on the periphery of the contour of the first through hole 201, and the cover plate body 2 supports the copper layer 112 on the plate body 110, avoiding the peeling of the combination surface between the copper layer 112 and the aluminum layer 111 due to tensile stress, and at the same time, the amount of copper can be further reduced, thereby reducing the cost. The periphery of the contour line of the first through hole 201 refers to one side of the first through hole 201 in a direction away from the center of the first through hole 201.

[0057] In one embodiment, the pole 1 is made of a copper-aluminum composite plate, and the plate body 110 and the column 120 are integrally formed. The copper-aluminum composite plate is a forming material, and the copper material and the aluminum material in the copper-aluminum composite plate are combined together and cannot be separated, have good combination stability, and have the advantages of high strength, durability, cost performance, etc. The entire pole 1 is made of a copper-aluminum composite plate, and the integrally formed processing process is simple, avoiding the traditional friction welding process of the copper layer and the aluminum layer. The copper-aluminum composite plate is simple to process, has high material utilization, has a stable structure, reduces cost, and has a large contact area of the copper-aluminum combination surface, thereby enhancing the current-carrying capacity of the pole 1, and preventing the pole from being melted in the case of passing a large current in the pole 1, thereby avoiding the out-of-control of the battery and improving safety.

[0058] In one embodiment, the electrode post 1 is processed by one or a combination of cold heading, stamping, and machining. The electrode post 1 is directly processed from a copper-aluminum composite plate, and can be processed by cold heading, stamping, or machining, or by a combination of these processes. The processing method is simple, offers many options, and is easy to operate. Optionally, the electrode post 1 can be processed by a combination of stamping and machining to facilitate the production of the desired electrode post shape.

[0059] In one embodiment, further referring to Figures 1 to 5 and Figures 9 to 10, the copper layer 112 is annular, and the pillar 120 includes an aluminum pillar portion 121 and a copper pillar portion 122. The aluminum pillar portion 121 protrudes from a portion of the first side surface of the aluminum layer 111 in a direction away from the aluminum layer 111. The copper pillar portion 122 has a recessed portion 123 that opens toward the plate body 110. The recessed portion 123 engages with the aluminum pillar portion 121 so that the copper pillar portion 122 encloses the aluminum pillar portion 121. The open end of the copper pillar portion 122 is connected to the inner ring of the copper layer 112. Since the copper layer 112 is annular, the outer contour of the copper layer 112 refers to the contour of the outer ring of the annular shape. By configuring the column 120 to include an aluminum column portion 121 integrally connected to the aluminum layer 111 and a copper column portion 122 integrally connected to the copper layer 112, the recessed portion 123 on the copper column portion 122 is connected to the aluminum column portion 121, and the open end of the recessed portion 123 is connected to the inner ring of the copper layer 112, thus achieving the effect of the copper column portion 122 wrapping the aluminum column portion 121. This makes the column 120 appear to be made of pure copper, but in reality, it is a copper-aluminum composite material. Furthermore, since the aluminum column portion 121 protrudes from the surface of the aluminum layer 111, the copper-aluminum bonding surface formed between the copper and aluminum materials on the cross-section of the plane where the center line of the pole column 1 is located is an inverted "V"-shaped continuous surface. This has a larger area than the traditional planar bonding surface, resulting in higher composite strength and less copper usage. Here, "the copper column portion 122 wrapping the aluminum column portion 121" means that the copper column portion 122 wraps around the outer peripheral surface of the aluminum column portion 121 and the end face of the aluminum column portion 121 away from the aluminum layer 111.

[0060] It should be noted that a first bonding surface 113 is formed on the plate 110 between the aluminum layer 111 and the copper layer 112, and a second bonding surface 124 is formed on the column 120 between the end of the aluminum column portion 121 away from the aluminum layer 111 and the copper column portion 122. There is a height difference between the first bonding surface 113 and the second bonding surface 124, that is, a part of the aluminum material extends into the area wrapped by the copper material. This can reduce the amount of copper used and reduce costs, and increase the area and complexity of the copper-aluminum bonding surface, thereby increasing the strength of the composite surface. The first bonding surface 113 and the second bonding surface 124 are both part of the entire copper-aluminum bonding surface.

[0061] In this design, the aluminum column portion 121 of the column 120 is formed by a portion of the aluminum layer 111 protruding, meaning that the aluminum column portion 121 and the aluminum layer 111 are a single unit; the recessed portion 123 on the copper column portion 122 is formed by a portion of the surface of the copper column portion 122 near the plate 110, recessed in a direction away from the plate 110; the open end of the copper column portion 122 refers to the end of the copper column portion 122 where the recessed portion 123 is provided; the connection between the recessed portion 123 on the copper column portion 122 and the aluminum column portion 121 means that the shape and size of the recessed portion 123 and the aluminum column portion 121 are similar. The copper pillar 122 is adapted to enclose the aluminum pillar 121, and the copper pillar 122 and the aluminum pillar 121 are tightly fitted together. The copper layer 112 is ring-shaped, which can be a circular ring, an elliptical ring, a square ring, or other ring shapes, and can match the outer contour of the pillar 120 and the plate 110. The ring shape has an inner ring and an outer ring. The open end of the copper pillar 122 is connected to the inner ring of the copper layer 112, so that the copper layer 112 is connected around the end of the copper pillar 122 near the aluminum layer 111, that is, it has the shape shown in Figures 2 and 10. The copper pillar 122 and the copper layer 112 are a whole.

[0062] In other embodiments, further referring to Figures 6 to 8 and Figure 11, the copper layer 112 is plate-shaped or ring-shaped, and the pillar 120 is a copper pillar portion 122, with one end of the copper pillar portion 122 near the plate 110 connected to the copper layer 112. In this case, the pillar 120 only includes the copper pillar portion 122 and does not contain the aluminum pillar portion 121, which can still ensure that the pillar 120 has a pure copper appearance. The side of the plate 110 away from the pillar 120 is aluminum, and the plate 110 is a copper-aluminum composite material, which can ensure the welding of the pole and the tab as well as the welding of the aluminum bar sheet, and is also easier to process and shape. As one implementation, as shown in Figures 6 and 11, a first bonding surface 113 is formed only within the plate 110, the copper layer 112 is flat, the first bonding surface 113 is planar, and there is no second bonding surface 124. It can be understood that, as an alternative implementation, as shown in Figure 7, the copper layer 112 is annular, the first bonding surface 113 is formed within the plate 110, and the second bonding surface 124 is located at the interface between the plate 110 and the column 120. Alternatively, as another alternative implementation, as shown in Figure 8, the copper layer 112 can also be a plate with recesses, the openings of which are located on the side of the copper layer 112 facing the aluminum layer 111. The side of the aluminum layer 111 facing the copper layer 112 has a protrusion, the thickness of which does not exceed the thickness of the copper layer 112. The protrusion matches the recess, the first bonding surface 113 is an inverted "V" shape, and there is no second bonding surface 124.

[0063] In one embodiment, the thickness of the plate body 110 is a, and the minimum thickness of the aluminum layer 111 is b, satisfying: 1 / 3≤b / a<1. The thickness refers to the size along the extension direction of the center line of the pole, i.e., the size along the "thickness direction" indicated by the arrow in FIG. 2, FIG. 6 to FIG. 8, FIG. 10 to FIG. 11. If the ratio of the minimum thickness b of the aluminum layer 111 to the thickness a of the plate body 110 is less than 1 / 3, the ratio is too small, and along the thickness direction, the proportion of the aluminum layer 111 in the plate body 110 is too small, the aluminum layer 111 is too thin, the pole 1 is difficult to stamp and form, the forming effect is unstable, and in the process of welding the pole 1 and the aluminum tab, the penetration of the welding depth penetrates the aluminum layer 111, thereby affecting the first bonding surface 113, i.e., affecting the copper-aluminum bonding surface, damaging the connection strength and stability of the copper-aluminum bonding surface, thereby causing the plate body 110 to crack and fracture at the first bonding surface 113, damaging the pole 1; if the ratio of the minimum thickness b of the aluminum layer 111 to the thickness a of the plate body 110 is equal to 1, the plate body 110 is all aluminum layer 111, there is no copper layer 112, the copper-aluminum bonding surface is all located on the column body 120, the cover plate body 2 cannot support the copper layer, under the action of the rebound force of the sealing element 6, the copper-aluminum material is pulled and easily disconnected from the bonding surface, and the pole 1 has poor structural strength. Therefore, by setting the ratio of the minimum thickness b of the aluminum layer 111 to the thickness a of the plate body 110 to be greater than or equal to 1 / 3 and less than 1, the aluminum layer 111 can have sufficient thickness to ensure that the pole can be smoothly formed and the stability after forming is ensured, while avoiding the penetration of the aluminum layer 111 by the welding depth in the process of welding the tab, thereby avoiding the influence of welding on the copper-aluminum bonding surface, and ensuring that the plate body 110 has a copper layer 112, ensuring that the projection of the maximum area of the copper layer 112 on the cover plate body 2 is at least partially located outside the contour line of the first through hole 201, thereby ensuring that the cover plate body 2 can support the copper layer 112, avoiding the copper-aluminum bonding surface being pulled apart by stress, and improving the structural strength of the pole 1. Optionally, b / a=0.8.

[0064] It should be noted that the aluminum layer 111 is a part of the plate body 110, and thus the thickness of the aluminum layer 111 cannot be greater than the thickness of the plate body 110, i.e., b / a cannot be greater than 1. The minimum thickness of the aluminum layer 111 refers to the thickness of the aluminum layer 111 corresponding to the maximum thickness of the copper layer 112. Specifically, when the pole is in the shape shown in FIGS. 1-5, the copper layer 112 corresponds to the aluminum layer 111 in all regions of the plate body 110 except the region corresponding to the pole body 120, and thus the minimum thickness b of the aluminum layer 111 is the thickness of the aluminum layer corresponding to the copper layer 112 as shown in FIG. 2. When the pole is in the shape shown in FIG. 6, the copper layer 112 is in the shape of a flat plate and the aluminum layer 111 is in the shape of a flat plate, and thus the thickness of the aluminum layer 111 is uniform, and the minimum thickness b of the aluminum layer is the thickness of the aluminum layer on the plate body 110. When the pole is in the shape shown in FIG. 7, the minimum thickness b of the aluminum layer 111 is the thickness of the aluminum layer corresponding to the copper layer 112. When the pole is in the shape shown in FIG. 8, the thickness of the aluminum layer 111 is not uniform, and the thickness of the portion of the aluminum layer 111 corresponding to the protruding portion is greater, and thus the minimum thickness b of the aluminum layer 111 refers to the thickness of the portion of the aluminum layer 111 other than the protruding portion. When the pole is in the shape shown in FIGS. 9-11, the range of the aluminum layer 111 is greater than the range of the copper layer 112, and in the thickness direction, the copper layer 112 corresponds to only a portion of the aluminum layer 111, and the thickness of the portion of the aluminum layer 111 corresponding to the copper layer 112 is small, and the thickness of the copper layer 112 is uniform, and thus the minimum thickness b of the aluminum layer 111 refers to the thickness of the portion of the aluminum layer 111 corresponding to the copper layer 112 in the thickness direction in FIG. 10.

[0065] In one embodiment, the thickness a of the plate body 110 is in the range of 2mm≤a≤5mm. It should be noted that in the battery, the pole post 1 is mounted on the cover plate body 2, the plate body 110 is located on one side of the cover plate body 2, the post body 120 is arranged in the first through hole 201 on the cover plate body 2, and the first insulating piece 3 is further arranged between the plate body 110 and the cover plate body 2 to insulate and fix the pole post 1. The side of the plate body 110 away from the cover plate body 2 is welded with the aluminum tab. If the thickness a of the plate body 110 is less than 2mm, the thickness of the plate body 110 is too small, the plate body 110 is too thin, the structural strength of the plate body 110 is weak, and deformation is easy to occur. In the process of welding the plate body 110 and the aluminum tab, the plate body 110 may be welded through, or the heat generated by welding may be transmitted to the first insulating piece 3 in the thickness direction, which will cause the first insulating piece 3 to melt, the insulation fixing performance to be poor, and the melting of the first insulating piece 3 will change the resistance value thereof. When the resistance value of the first insulating piece 3 is out of range, the resistance of the cover plate is out of range, which will cause the edge resistance of the positive and negative poles of the battery to fluctuate greatly or be out of range, and then cause the edge voltage of the positive and negative poles to fluctuate greatly, the edge voltage consistency of the battery to be poor, and in severe cases, the battery internal electrolyte corrosion will occur. If the thickness a of the plate body 110 is greater than 5mm, the plate body 110 is too thick, which increases the weight of the pole post 1, increases the cost, and increases the overall height of the battery, which is not conducive to improving the volume energy density of the battery. Therefore, by setting the thickness a of the plate body 110 in the range of 2mm to 5mm, the plate body 110 can be prevented from being welded through during welding with the aluminum tab, and the welding heat can be prevented from being transmitted to the first insulating piece 3 in large quantities through the plate body 110, thereby preventing the first insulating piece 3 from melting, ensuring that the resistance value of the first insulating piece 3 will not fluctuate, thereby ensuring the consistency of the edge voltage of the positive and negative poles of the battery and preventing the electrolyte corrosion in the battery. In addition, the thickness of the plate body 110 can be prevented from being too thick to cause the pole post 1 to be too heavy, thereby facilitating cost reduction and improving the volume energy density of the battery.

[0066] Alternatively, the thickness a of the plate body 110 is in the range of 2mm≤a≤3mm. Alternatively, the thickness a of the plate body 110 is 2.5mm.

[0067] In one embodiment, the thickness b of the aluminum layer 111 is greater than or equal to 1.5 mm. It should be noted that the effective penetration depth of the welding between the aluminum tab and the pole 1 is generally 0.3-1.5 mm. If the thickness b of the aluminum layer 111 is less than 1.5 mm, the aluminum layer 111 is too thin, and the welding penetration depth can penetrate the aluminum layer 111, thereby affecting the copper-aluminum bonding surface, damaging the connection strength and stability of the copper-aluminum bonding surface, and causing the plate body 110 to crack at the first bonding surface 113, damaging the pole 1. In addition, the aluminum layer 111 being too thin can make the overall size of the plate body 110 too thin, and the heat transferred to the first insulating member 3 through the plate body 110 during the welding process can exceed the melting point of the first insulating member, causing the resistance value of the first insulating member 3 to fluctuate, resulting in poor consistency of the positive and negative electrode edge voltage of the battery, and even causing electrolyte corrosion inside the battery. Therefore, by setting the thickness b of the aluminum layer 111 to be greater than or equal to 1.5 mm, the maximum welding penetration depth between the aluminum tab and the pole 1 can be ensured not to penetrate the aluminum layer 111, and the copper-aluminum bonding surface is not affected. In addition, the welding heat transferred to the first insulating member 3 can be ensured not to exceed the melting point of the first insulating member 3, and the resistance value of the first insulating member 3 can be ensured not to fluctuate, thereby improving the consistency of the positive and negative electrode edge voltage of the battery and improving the electrical performance and safety performance of the battery. It should be noted that the thickness b of the aluminum layer 111 is less than the thickness a of the plate body 110.

[0068] Optionally, the thickness b of the aluminum layer 111 is 2 mm.

[0069] In one embodiment, the column body 120 is a cylindrical body, which is simple to process, easy to form, and has good stability. It can be understood that, as an alternative embodiment, the column body 120 can also be an elliptical cylindrical body, that is, the cross section of the column body 120 is elliptical, which is also easy to form and process, and can also increase the structural strength of the column body 120. It can be understood that, as another alternative embodiment, the column body 120 can also be a polygonal column body, that is, the cross section of the column body 120 is polygonal, and the outer peripheral surface of the polygonal column body is a spliced plane, which is simple to process. Of course, the column body 120 can also be other structures, such as a cross section of the column body 120 in the shape of a racetrack.

[0070] Optionally, the column body 120 is a rectangular body, which is easy to form. Optionally, the edges of the rectangular body are provided with rounded corners, which is convenient for assembly and can reduce stress concentration at the edges.

[0071] In one embodiment, the post 120 comprises a post body 126 connected to the plate body 110 and a boss 125 connected to the post body 126 away from the plate body 110, the center line of the boss 125 coincides with the center line of the post 120, and the cross-sectional area of the boss 125 is smaller than that of the post body 126. It should be noted that the cross-sectional area refers to the area in the plane perpendicular to the center line; the part of the post 120 other than the boss 125 is the post body 126, which is connected to the plate body 110. By constructing the boss 125 at the end of the post 120 away from the plate body 110, the center line of the boss 125 coincides with the center line of the post 120, and the cross-sectional area of the boss 125 is smaller than that of the post body 126, the boss 125 is suitable for being inserted into the fourth through hole 501 on the bottom plate 5, and the post body 126 is suitable for abutting against the bottom surface of the mounting groove 502 on the bottom plate 5, so as to realize the mutual limiting of the post 120 and the bottom plate 5, and facilitate the stability of assembly.

[0072] Optionally, the center line of the boss 125 and the center line of the post body 126 are both collinear with the center line of the plate body 110, that is, the center line of the post 120 is collinear with the center line of the plate body 110, which facilitates molding and is good in stability.

[0073] According to the embodiments of the present application, in another aspect, a cover plate assembly 200 is also provided, which is further described by taking the embodiment in which the outer contour of the copper layer 112 coincides with the outer contour of the aluminum layer 111 as an example. The cover plate assembly 200 comprises a cover plate body 2, a first insulating piece 3, a second insulating piece 4, a bottom plate 5, the above-mentioned post 1 and a sealing piece 6. The cover plate body 2 is provided with a first through hole 201; the first insulating piece 3 is arranged on one side of the cover plate body 2, and the first insulating piece 3 is provided with a second through hole 301; the second insulating piece 4 is arranged on the side of the cover plate body 2 away from the first insulating piece 3, and the second insulating piece 4 is provided with a third through hole 401; the bottom plate 5 is arranged on the side of the second insulating piece 4 away from the cover plate body 2, and the bottom plate 5 is provided with a fourth through hole 501; the post body 120 of the post 1 is arranged in the fourth through hole 501 after sequentially passing through the second through hole 301, the first through hole 201 and the third through hole 401, and the plate body 110 of the post abuts against the side of the first insulating piece 3 away from the cover plate body 2; the sealing piece 6 is arranged between the post 120 and the cover plate body 2, and the inner side of the sealing piece 6 abuts against the outer circumferential surface of the post 120 and the outer side abuts against the inner wall of the first through hole 201.

[0074] It should be noted that the sealing member 6 is a sealing ring, which is sleeved outside the column body 120 of the pole column 1, and has elasticity and a tendency to contract in the direction of the column body 120. Therefore, if the outer contour of the copper layer 112 on the pole column 1 is within the contour range of the first through hole 201 on the cover plate body 2, and the projection of the copper-aluminum bonding surface on the cover plate body 2 is within the range of the first through hole 201, without the cover plate body 2 providing support to the copper layer 112 in the up-down direction, the action of the sealing member 6 on the column body 120 at the copper-aluminum bonding surface generates a downward tensile stress, which makes the reliability of the copper-aluminum bonding surface poor and prone to breakage. By using the battery of the present embodiment, when the pole column 1 is inserted into the first through hole 201, at least a part of the copper-aluminum bonding surface is located outside the periphery of the first through hole 201, and the cover plate body 2 has an upward supporting force on the copper layer 112 on the plate body 110. Even if the column body 120 is pulled by the rebounding force of the sealing member 6, the copper layer 112 and the aluminum layer 111 will not be separated at the bonding surface due to the tensile stress, thereby effectively preventing the composite pole column 1 from breaking at the bonding surface and ensuring the quality of the battery. The up-down direction refers to the direction of the "up-down" indicated by the arrow in FIG. 18.

[0075] Specifically, the cover plate body 2 is provided with a first recess 202, the first through hole 201 is arranged in the first recess 202, and the first recess 202 is used to accommodate and limit the first insulating member 3. The first insulating member 3 is provided with a second recess 302 on the side away from the cover plate body 2, and the second through hole 301 is arranged in the second recess 302. The second recess 302 is used to accommodate the plate body 110 of the pole column 1. The second insulating member 4 is provided with a third through hole 401, and the second insulating member 4 is located on the different side of the first insulating member 3 relative to the cover plate body 2. The bottom plate 5 is provided with a mounting groove 502, which is recessed from the surface of the side of the bottom plate 5 close to the cover plate body 2 to the direction away from the cover plate body 2. The fourth through hole 501 is arranged in the mounting groove 502, and the mounting groove 502 is used to abut against the column body 120. The first through hole 201, the second through hole 301, the third through hole 401, and the fourth through hole 501 are sequentially penetrated by the column body 120 of the pole column 1, and then the boss 125 on the column body 120 penetrates the fourth through hole 501.

[0076] Specifically, the sealing member 6 is sleeved on the column body 120 of the pole column 1 and located between the cover plate body 2, the first insulating member 3, the second insulating member 4, and the bottom plate 5. The sealing member 6 has an insulating effect on the column body 120, the cover plate body 2, and the bottom plate 5, and a sealing effect on the cover plate and the battery.

[0077] In one embodiment, the first insulating member 3 and the second insulating member 4 are both made of plastic, which has good insulation and stable performance.

[0078] Optionally, the material of the first insulating piece 3 is PPS (polyphenylene sulfide), which has the advantages of high mechanical strength, high temperature resistance, corrosion resistance, good thermal stability, excellent electrical properties, and the like. The melting point of the first insulating piece 3 is 280°C, which is relatively high. According to different specific types, the resistance value of the first insulating piece 3 is 5Ω-100000Ω or greater than 200MΩ. When the first insulating piece 3 is of the type with a resistance value of 5Ω-100000Ω, the resistance value of the first insulating piece 3 out of range can be lower than 5Ω or higher than 100000Ω. When the first insulating piece 3 is of the type with a resistance value greater than 200MΩ, the resistance value of the first insulating piece 3 out of range refers to a resistance value lower than 200MΩ. Optionally, the first insulating piece 3 has a resistance value greater than 200MΩ.

[0079] In an embodiment, the material of the sealing piece 6 is rubber, which has good elasticity, excellent heat resistance, and good electrical insulation performance. Rubber is relatively common, easy to obtain, and low in cost.

[0080] In an embodiment, the bottom plate 5 is provided with a mounting groove 502, and the fourth through hole 501 is located in the mounting groove 502. The cross-sectional area of the fourth through hole 501 is smaller than that of the column body 126 of the pole 1. The column body 126 abuts against the mounting groove 502, and the boss 125 on the column 120 is arranged in the fourth through hole 501. The cross-sectional area of the fourth through hole 501 refers to the opening area of the fourth through hole 501 on the bottom plate 5. By arranging the mounting groove 502 on the bottom plate 5 and the fourth through hole 501 in the mounting groove 502, when the pole 1 is combined with the bottom plate 5, because the cross-sectional area of the fourth through hole 501 is smaller than that of the column body 126, the column body 126 cannot penetrate into the fourth through hole 501, and the end face of the column body 126 close to the boss 125 abuts against the bottom surface of the mounting groove 502, thereby achieving mutual limiting of the bottom plate 5 and the column body 126 along the axial direction of the pole 1, preventing the bottom plate 5 from further moving towards the cover plate body 2, and at the same time, the boss 125 of the column 120 is arranged in the fourth through hole 501, and the fourth through hole 501 limits the boss 125 in the radial direction, thereby achieving relative fixation of the bottom plate 5 and the column 120, which is convenient to assemble and has good stability. The radial direction refers to the direction perpendicular to the center line.

[0081] Optionally, the cross-sectional area of the mounting groove 502 is the same as that of the column body 126 of the column 120, and the column body 126 is embedded in the mounting groove 502. The mounting groove 502 and the column body 126 are mutually limited in both the axial direction of the pole and the radial direction of the pole, thereby further improving the stability of assembly, and the column 120 is closely attached to the bottom plate 5, which has good electrical conductivity.

[0082] In one embodiment, the boss 125 is welded with the bottom plate 5. The boss 125 is arranged in the fourth through hole 501 on the bottom plate 5, and the outer circumferential surface of the boss 125 is attached to the inner wall of the fourth through hole 501. By welding the boss 125 with the bottom plate 5, the fixed connection between the pole post 1 and the bottom plate 5 is achieved, and the riveting process between the traditional pole post and the bottom plate is cancelled. On the premise of ensuring the structural strength, the process cost of the cover plate assembly 200 is reduced.

[0083] Specifically, the welding is performed at the edge position where the boss 125 is attached to the bottom plate 5 away from the one end of the post body 126, so as to realize the welding of the boss 125 and the bottom plate 5. The operation is facilitated, the welding process is simple, and the welding reliability is high.

[0084] Alternatively, the boss 125 and the bottom plate 5 are connected by riveting and / or laser seam welding to form a weld 9. Alternatively, the boss 125 and the bottom plate 5 are directly laser seam welded, which is simple to operate and has high reliability.

[0085] In one embodiment, a third recess 503 is formed on the bottom plate 5 away from the mounting groove 502. The third recess 503 is recessed from the part of the surface of the bottom plate 5 away from the mounting groove 502 towards the mounting groove 502. The cross-sectional area of the third recess 503 is greater than that of the fourth through hole 501. The third recess 503 and the mounting groove 502 are communicated through the fourth through hole 501, but the bottom surface of the third recess 503 is spaced apart from the bottom surface of the mounting groove 502. After the post body 120 is inserted into the fourth through hole 501 on the bottom plate 5, the outer circumferential surface of the boss 125 is attached to the inner wall of the fourth through hole 501. The end surface of the one end of the boss 125 away from the plate body 110 is flush with the bottom surface of the third recess 503. The edge of the one end of the boss 125 away from the plate body 110 is attached to the edge of the fourth through hole 501 away from the cover plate body 2. The welding operation is performed along the edge of the boss 125 in the third recess 503, so as to realize the welding of the pole post 1 and the bottom plate 5. The weld 9 formed by the welding falls in the third recess 503, so as to avoid the weld 9 protruding from the surface of the bottom plate 5 away from the cover plate body 2. This is beneficial to ensure the flatness of the surface of the bottom plate 5, thereby improving the connection quality between the bottom plate 5 and the tabs of the pole group. The outer circumferential surface refers to the surface of the boss 125 away from the axial direction.

[0086] According to the embodiments of the present application, in another aspect, a battery is also provided, as shown in FIG. 21. The battery comprises a shell 7, the cover plate assembly 200 and a pole group 8. The shell 7 has an open end. The cover plate assembly 200 is arranged at the open end of the shell 7 to close the shell 7. The pole group 8 is arranged inside the shell 7. The end of the pole group 8 has a tab 801, and the tab 801 is electrically connected with the bottom plate 5 in the cover plate assembly 200. Alternatively, the battery is a lithium ion battery.

[0087] In one embodiment, both ends of the battery are open ends, one end of which is provided with the cover plate assembly 200 of the embodiment, and the other end is provided with another cover plate assembly.

[0088] The following describes the test results of the pole of the battery using different parameter values, to verify the parameter values of the pole.

[0089] Table 1 is the verification result of stress analysis of the pole in the assembled battery when the different size relationship between the projection area S1 of the outer contour of the copper layer 112 on the pole 1 on the surface of the cover plate body 2, the area S0 occupied by the first through hole 201 on the surface of the cover plate body 2, and the projection area S2 of the aluminum layer 111 on the surface of the cover plate body 2.

[0090] Table 1 Influence of the projection area S1 of the copper layer on the cover plate body on the verification result

[0091] As can be seen from Table 1, for the implementation case 1, the relationship among S0, S1 and S2 is S0 < S1 < S2, and within the range defined in the present application, the area S of the overlapping region of the projection of the copper layer 112 on the cover plate body 2 and the surface of the cover plate body 2 is greater than 0, that is, the size of the outer contour of the copper layer 112 is greater than the size of the contour of the first through hole 201 and smaller than the size of the outer contour of the aluminum layer 111, the cover plate body 2 can provide a supporting force to the copper layer 112 on the plate body 110 in the direction of the plate body 110, the tensile stress of the sealing element 6 between the copper layer and the aluminum layer on the pole 1 is relieved, the structural reliability is good, and it has certain application value; for the implementation case 2, S0, S1 and S2 satisfy the relationship S0 < S1 = S2, and within the range defined in the present application, the area S of the overlapping region of the projection of the copper layer 112 on the cover plate body 2 and the surface of the cover plate body 2 is greater than 0, at this time, the outer contour of the copper layer 112 coincides with the outer contour of the aluminum layer 111, the first bonding surface 113 on the plate body 110 reaches the maximum, the cover plate body 2 can provide sufficient supporting force to the copper layer 112 on the plate body 110 in the direction of the plate body 110, the copper layer and the aluminum layer on the pole are not subjected to tensile stress, the structural reliability is good, and the application effect is optimal; however, in the comparative example 1, S1 < S0, which is not within the range defined in the present application, and correspondingly, there is no overlapping region of the projection of the copper layer 112 on the cover plate body 2 and the surface of the cover plate body 2, the copper layer and the aluminum layer on the pole are subjected to tensile stress, the structural reliability is poor, and the stress test fails; in the comparative example 2, S1 > S2, which is within the range defined in the present application, and correspondingly, the size of the outer contour of the copper layer 112 is greater than the size of the outer contour of the aluminum layer 111, that is, the copper layer 112 wraps the aluminum layer 111, although the area S of the overlapping region of the projection of the copper layer 112 on the cover plate body 2 and the surface of the cover plate body 2 is greater than 0, the copper layer and the aluminum layer on the pole are not subjected to tensile stress, but since the copper layer 112 wraps the aluminum layer 111, the copper layer 112 occupies a certain area on the surface of the plate body 110 away from the pole body 120, which makes the surface area of the aluminum layer 111 small, reduces the weldable area of the aluminum pad on the pole, is not conducive to welding and overcurrent, and increases the use amount of copper, resulting in increased cost, which is not suitable for use.

[0092] In summary, when the projected area of the outer contour of the copper layer 112 on the surface of the cover plate body 2 is S1, which is greater than the area S0 of the first through hole 201 and less than or equal to the projected area S2 of the aluminum layer 111 on the surface of the cover plate body 2, at least a part of the copper-aluminum bonding surface on the plate body 110 is located on the periphery of the first through hole 201, the support effect of the cover plate body 2 on the copper layer 112 on the plate body 110 is achieved, and even in the case of pulling the column body 120 due to the rebounding force of the sealing element 6, the copper layer 112 and the aluminum layer 111 will not be separated due to the tensile stress, thereby effectively preventing the composite pole 1 from being broken at the bonding surface, improving the quality of the pole 1, meeting the welding requirements of the pole and the aluminum tab, meeting the overcurrent capacity of the pole, and also avoiding excessive use of copper, thereby reducing the cost.

[0093] Table 2 shows the ratio of the thickness b of the aluminum layer 111 to the thickness a of the plate body 110, the forming results of the pole, and the verification results after the pole is assembled into the battery.

[0094] Table 2 shows the ratio of the thickness b of the aluminum layer 111 to the thickness a of the plate body 110, the forming results of the pole, and the verification results after the pole is assembled into the battery.

[0095] As can be seen from Table 2, for the implementation case 3, the ratio of the thickness b of the aluminum layer 111 to the thickness a of the plate body 110 is 0.8, which is within the range defined in the present application, the pole forming is stable, and the effect is optimal; for the implementation case 4, the ratio of the thickness b of the aluminum layer 111 to the thickness a of the plate body 110 is 1 / 3, which is a critical value within the range defined in the present application, and the pole basically meets the forming effect; however, in the comparative example 3, the ratio of the thickness b of the aluminum layer 111 to the thickness a of the plate body 110 is 1 / 4, which is less than 1 / 3 and is not within the range defined in the present application, the pole stamping forming is difficult, the forming effect is unstable, and after the pole is assembled into the battery, there is a crack between the copper layer 112 and the aluminum layer 111 on the plate body; in the comparative example 4, the ratio of the thickness b of the aluminum layer 111 to the thickness a of the plate body 110 is 1, i.e., the plate body 110 is entirely made of the aluminum layer 111, and there is no copper layer 112, which is not within the range defined in the present application, the structural strength of the pole 1 with this structure is poor, the copper-aluminum layers are subjected to tensile stress, and the pole is prone to be broken at the bonding surface.

[0096] In summary, when the ratio of the thickness b of the aluminum layer 111 to the thickness a of the plate body 110 satisfies 1 / 3≤b / a<1, the aluminum layer 111 can have sufficient thickness to ensure that the pole can be smoothly formed and the stability after forming is ensured, and the plate body 110 can have the copper layer 112, so that the projection of the maximum area of the copper layer 112 on the cover plate body 2 is at least partially located outside the contour line of the first through hole 201, so that the cover plate body 2 can support the copper layer 112, avoid the copper-aluminum joint from being disconnected due to tensile stress, and improve the structural strength of the pole 1.

[0097] Table 3 is the verification result of the welding result of the pole and the aluminum tab in the battery when the thickness a of the plate body 110 adopts different values.

[0098] Table 3 shows the influence of different values of the thickness a of the plate body on the verification result.

[0099] As can be seen from Table 3, for the implementation cases 5 to 11, the thickness a of the plate body 110 is within the range of 2mm≤a≤5mm defined in the present application, the strength of the plate body 110 of the pole 1 is sufficient, the welding performance is good after the aluminum tab is welded on the plate body 110, the first insulating part 3 is not melted, and the resistance value of the first insulating part 3 is not out of range, and the effect of the implementation case 6 is optimal; however, for the comparative example 5, the thickness a of the plate body 110 is 1mm, which is less than 2mm and is not within the value range defined in the present application, the strength of the plate body 110 is insufficient, the first insulating part 3 is severely melted after being welded with the aluminum tab, and the resistance value of the first insulating part 3 is out of range; for the comparative example 6, the thickness a of the plate body 110 is 1.5mm, which is less than 2mm and is not within the value range defined in the present application, although the strength of the plate body 110 is sufficient, the first insulating part 3 is melted and the resistance value is out of range after being welded with the aluminum tab, and the molten pool touches the first insulating part 3; for the comparative examples 7 and 8, the thickness a of the plate body 110 is 5.5mm and 6mm respectively, which are both greater than 5mm and are not within the value range defined in the present application, although the aluminum tab can be welded, the plate body 110 is too thick, the weight of the pole is too large, and the cost is high.

[0100] In summary, when the thickness a of the plate body 110 is within the range of 2mm to 5mm, the plate body 110 can be prevented from being welded through during the welding process with the aluminum tab, the welding heat can be prevented from being transmitted to the first insulating part 3 through the plate body 110, so that the first insulating part 3 is prevented from being melted, the resistance value of the first insulating part 3 is prevented from fluctuating, the consistency of the positive and negative electrode edge voltage of the battery is ensured, the electrolyte corrosion in the battery is prevented, and the plate body 110 can be prevented from being too thick to cause the weight of the pole 1 to be too large, so that the cost is reduced and the volume energy density of the battery is improved.

[0101] Table 4 is the thickness b of the aluminum layer 111 takes different values, the corresponding verification results of the welding results of the pole and the aluminum tab in the battery.

[0102] Table 4 The influence of different values of the thickness b of the aluminum layer on the verification results

[0103] As can be seen from Table 4, the thickness b of the aluminum layer 111 in the implementation case 12 is 1.5 mm, and the thickness b of the aluminum layer 111 in the implementation case 13 is 2 mm, both of which are within the range of b≥1.5 mm defined in the present application, the strength of the plate body 110 is sufficient, and after the aluminum tab is welded on the pole, the welding performance is good, and the effect of the implementation case 13 is the best; the thickness b of the aluminum layer 111 in the implementation case 14 is 2.5 mm, and the thickness b of the aluminum layer 111 in the implementation case 15 is 3 mm, both of which are greater than 1.5 mm and within the range defined in the present application, the strength of the plate body 110 is sufficient, and the aluminum tab welding is met, the welding performance is good, but the cost is slightly higher than that of the implementation cases 12 and 13; however, for the comparative example 9, the thickness b of the aluminum layer 111 is 1 mm, which is less than 1.5 mm and not within the range defined in the present application, the strength of the plate body 110 is insufficient, the penetration depth after the aluminum tab is welded may penetrate the copper-aluminum bonding surface, the copper-aluminum interfacial peeling force decreases, the first plastic part melts and the resistance value exceeds the range; for the comparative example 10, the thickness b of the aluminum layer 111 is 1.2 mm, which is less than 1.5 mm and not within the range defined in the present application, after the aluminum tab is welded on the pole, the penetration depth may penetrate the copper-aluminum bonding surface, the copper-aluminum interfacial peeling force decreases, and the first plastic part melts and the resistance value exceeds the range.

[0104] In summary, when the thickness b of the aluminum layer 111 is greater than or equal to 1.5 mm, the maximum penetration depth of the aluminum tab and the pole 1 can be ensured not to penetrate the aluminum layer 111, which does not affect the copper-aluminum bonding surface, and the welding heat transferred to the first insulating part 3 can be ensured not to exceed the melting point of the first insulating part 3, which ensures that the first insulating part 3 does not fluctuate in resistance value, thereby improving the consistency of the positive and negative electrode edge voltage of the battery and improving the electrical performance and safety performance of the battery. However, the thickness b of the aluminum layer cannot be too large, otherwise the cost will increase, and the thickness b of the aluminum layer cannot exceed the maximum value of the thickness a of the plate body 110.

[0105] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A pole, characterized in that The application relates to a pole body, which comprises an aluminum layer and a copper layer, the copper layer being connected to at least a part of the first side of the aluminum layer; a column body being connected to the first side of the plate body, at least a part of the copper layer being connected to the outer circumferential side of the column body, at least a part of the column body being a copper column part, the copper column part covering the outer surface of the column body and being fixedly connected to the copper layer; the column body being adapted to be arranged in a first through hole of a cover plate body, the area of the first through hole on the surface of the cover plate body being S0, the area of the projection of the outer contour of the copper layer on the surface of the cover plate body being S1, and the projection area of the aluminum layer on the surface of the cover plate body being S2, wherein S0 < S1 <= S2. The copper layer is annular, the column body comprises an aluminum column part and a copper column part, the aluminum column part being formed by protruding from the part of the first side of the aluminum layer towards the direction away from the aluminum layer, the copper column part being provided with a recess part opening towards the plate body, the recess part being connected to the aluminum column part to make the copper column part wrap the aluminum column part, and the opening end of the copper column part being connected to the inner ring of the copper layer. Alternatively, the column body is a copper column part, one end of the copper column part close to the plate body being connected to the copper layer. The thickness of the plate body is a, and the minimum thickness of the aluminum layer is b, and 1 / 3 <= b / a < 1 is satisfied.

2. The pole according to claim 1, characterized in that The thickness a of the plate body is 2mm <= a <= 5mm. And / or, the minimum thickness b of the aluminum layer is b >= 1.5mm.

3. The pole according to claim 1, wherein The pole body is made of a copper-aluminum composite plate, and the plate body and the column body are integrally formed.

4. The pole according to claim 3, characterized in that The column body is a cylindrical body, an elliptical cylindrical body or a polygonal cylindrical body. And / or, the column body comprises a column body and a boss, the column body is connected to the plate body, the boss is connected to one end of the column body away from the plate body, the center line of the boss is coincident with the center line of the column body, and the cross-sectional area of the boss is smaller than that of the column body.

5. The pole as claimed in claim 1, characterized in that The application relates to a pole body, which comprises an aluminum layer and a copper layer, the copper layer being connected to at least a part of the first side of the aluminum layer; a column body being connected to the first side of the plate body, at least a part of the copper layer being connected to the outer circumferential side of the column body, at least a part of the column body being a copper column part, the copper column part covering the outer surface of the column body and being fixedly connected to the copper layer; the column body being adapted to be arranged in a first through hole of a cover plate body, the area of the first through hole on the surface of the cover plate body being S0, the area of the projection of the outer contour of the copper layer on the surface of the cover plate body being S1, and the projection area of the aluminum layer on the surface of the cover plate body being S2, wherein S0 < S1 <= S2.

6. The pole according to any one of claims 1 to 5, characterized in that The pole body is made of a copper-aluminum composite plate, and the plate body and the column body are integrally formed. The column body is a cylindrical body, an elliptical cylindrical body or a polygonal cylindrical body.

7. A cover plate assembly characterized by, And / or, the column body comprises a column body and a boss, the column body is connected to the plate body, the boss is connected to one end of the column body away from the plate body, the center line of the boss is coincident with the center line of the column body, and the cross-sectional area of the boss is smaller than that of the column body. The application relates to a pole body, which comprises an aluminum layer and a copper layer, the copper layer being connected to at least a part of the first side of the aluminum layer; a column body being connected to the first side of the plate body, at least a part of the copper layer being connected to the outer circumferential side of the column body, at least a part of the column body being a copper column part, the copper column part covering the outer surface of the column body and being fixedly connected to the copper layer; the column body being adapted to be arranged in a first through hole of a cover plate body, the area of the first through hole on the surface of the cover plate body being S0, the area of the projection of the outer contour of the copper layer on the surface of the cover plate body being S1, and the projection area of the aluminum layer on the surface of the cover plate body being S2, wherein S0 < S1 <= S2. The pole body is made of a copper-aluminum composite plate, and the plate body and the column body are integrally formed. The column body is a cylindrical body, an elliptical cylindrical body or a polygonal cylindrical body. And / or, the column body comprises a column body and a boss, the column body is connected to the plate body, the boss is connected to one end of the column body away from the plate body, the center line of the boss is coincident with the center line of the column body, and the cross-sectional area of the boss is smaller than that of the column body. ​ ​ 8. The cover plate assembly of claim 7, wherein, The bottom plate is provided with a mounting groove, the fourth through hole is located in the mounting groove, a cross-sectional area of the fourth through hole is smaller than a cross-sectional area of the column body on the pole column, the column body abuts against the mounting groove, and the boss on the column passes through the fourth through hole; And / or, the first insulating member and the second insulating member are both made of plastic. And / or, the sealing member is made of rubber.

9. The cover plate assembly of claim 8, wherein, The boss is welded to the bottom plate.

10. A battery, characterized by Comprise: A shell having an open end; The cover plate assembly according to any one of claims 7 to 9 is arranged at the open end of the shell to close the shell; A pole group is arranged inside the shell, an end of the pole group has a pole lug, and the pole lug is electrically connected to the bottom plate in the cover plate assembly.

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