Single battery

Abstract

The invention discloses a single battery, the single battery comprises a first conductive member, a second conductive member and a cell assembly, specifically, the first conductive member is provided with a conductive hole, and the conductive hole penetrates through the first conductive member in the thickness direction of the first conductive member; the second conductive piece penetrates through the conductive hole, and the second conductive piece and the first conductive piece are fixed and electrically connected; and the battery core assembly is welded with the second conductive piece. Compared with the prior art, the material selection of the second conductive part is slightly limited by the structural strength, and the welding performance of the second conductive part and the battery cell assembly is good.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a single battery. Background Art

[0002] The busbar is an important part of the battery, responsible for collecting and converging the current of the battery cells, while the outer shell, as another important part of the battery, is responsible for sealing and protecting the internal structure of the battery. Due to their different functions, the two are usually made of different materials. A common configuration is a copper busbar with an aluminum alloy outer shell. Due to the large difference in their melting points and fluidity, there are certain obstacles when welding the busbar and the outer shell, which can easily lead to incomplete welding on one side or overburning on the other side, which affects the electrical performance and service life of the battery. Summary of the invention

[0003] An object of the present invention is to provide a single cell, which aims to solve the technical problem that parameters are difficult to match and welding effect is poor when the shell and the busbar are welded together.

[0004] To achieve the above-mentioned purpose, the present invention provides a solution: a single battery, which includes a first conductive member, a second conductive member and a battery cell assembly. Specifically, the first conductive member is provided with an electrical conductive hole, and the electrical conductive hole penetrates the first conductive member in the thickness direction of the first conductive member; the second conductive member is penetrated by the electrical conductive hole, and the second conductive member is fixed to and electrically connected to the first conductive member; and the battery cell assembly is welded and connected to the second conductive member.

[0005] In some embodiments of the present application, a welding hole is further formed on the second conductive member, and an opening direction of the welding hole is toward a side of the second conductive member away from the battery cell assembly.

[0006] In some embodiments of the present application, the diameter of the conductive hole is D1, the diameter of the welding hole is D2, and 30%≤D2 / D1≤90%.

[0007] In some embodiments of the present application, the depth of the welding hole is L1, the projection length of the second conductive member in the thickness direction of the first conductive member is L2, and 50%≤L1 / L2≤90%.

[0008] In some embodiments of the present application, the minimum distance between the hole wall of the welding hole and the outer wall of the second conductive member is L3, and L3 is ≥ 0.05 mm.

[0009] In some embodiments of the present application, the distance between the bottom of the welding hole and the surface of the second conductive member on one side close to the battery cell assembly is L4, and 0.05mm≤L4≤2mm.

[0010] In some embodiments of the present application, the battery cell assembly includes a battery cell and a busbar, and the busbar is electrically connected to the battery cell and the second conductive member, respectively.

[0011] In some embodiments of the present application, the area of ​​the first conductive member close to the battery cell assembly is S1, the projected area of ​​the contact surface between the second conductive member and the busbar on the first conductive member is S2, and 20%≤S2 / S1≤90%.

[0012] In some embodiments of the present application, the second conductive element is connected to the busbar through a first weld, the projection area of ​​the first weld on the busbar surface is S3, the surface area of ​​the busbar close to the first conductive element structure is S4, and S3 / S4≥10%.

[0013] In some embodiments of the present application, the second conductive member is welded to a side of the busbar close to the first conductive member, and a side of the busbar away from the second conductive member is electrically connected to the battery cell.

[0014] In some embodiments of the present application, the second conductive member and the busbar are made of the same material.

[0015] In some embodiments of the present application, the battery cell assembly includes a winding core and a pole tab that are electrically connected, and the pole tab is welded to the second conductive member.

[0016] In some embodiments of the present application, the second conductive member and the tab are made of the same material.

[0017] In some embodiments of the present application, there are multiple conductive holes, and the second conductive members are arranged corresponding to the conductive holes one by one.

[0018] In some embodiments of the present application, a plurality of electrical conductive holes are arranged in a circular array on the first conductive member.

[0019] In some embodiments of the present application, the material of the second conductive member includes copper.

[0020] In some embodiments of the present application, the single battery further includes a first isolation layer, the first isolation layer wraps the second conductive member, and a side of the second conductive member close to the battery cell assembly is at least partially exposed.

[0021] In some embodiments of the present application, the material of the first isolation layer includes at least one of steel and nickel.

[0022] In some embodiments of the present application, the area of ​​the exposed portion of the second conductive member on one side close to the battery cell assembly is S5, the area of ​​the first conductive member on one side close to the battery cell assembly is S1, and 40%≤S5 / S1≤100%.

[0023] In some embodiments of the present application, the second conductive member and the first conductive member are fixed by riveting.

[0024] In some embodiments of the present application, the first conductive member includes a first surface and a second surface relative to each other, and the second conductive member includes a rivet seat, a rivet column and a rivet buckle connected in sequence. Specifically, the rivet column is provided with an electrical conductive hole; the rivet seat is connected to one end of the rivet column, and the rivet seat abuts against the first surface; the rivet buckle is connected to an end of the rivet column away from the rivet seat, and the rivet buckle is riveted to the second surface.

[0025] In some embodiments of the present application, an outer edge of one end of the rivet button away from the rivet seat is provided with an outer chamfer, and on any cross section passing through the axis of the rivet button, an angle between the outer chamfer and the second surface is A1, 10°≤A1≤85°.

[0026] In some embodiments of the present application, the distance between the outer edge of the outer chamfer and the second surface is L5, the thickness of the rivet is L6, and 0≤L5 / L6≤70%.

[0027] In some embodiments of the present application, the thickness of the rivet is L6, the projection length of the second conductive member in the thickness direction of the rivet is L7, and 10%≤L6 / L7≤40%.

[0028] In some embodiments of the present application, the diameter of the conductive hole is D1, the outer diameter of the rivet is D3, and 120%≤D3 / D1≤200%.

[0029] In some embodiments of the present application, the diameter of the rivet seat is D4, 2mm≤D4≤20mm.

[0030] In some embodiments of the present application, the diameter of the conductive hole is D1, the diameter of the rivet seat is D4, and 130%≤D4 / D1≤200%.

[0031] In some embodiments of the present application, the thickness of the rivet seat is L8, 0.05mm≤L8≤2mm.

[0032] In some embodiments of the present application, the single cell further includes a first isolation sleeve, the rivet column passes through the first isolation sleeve, and the rivet seat and the first surface clamp the first isolation sleeve.

[0033] In some embodiments of the present application, the diameter of the rivet seat is D4, the outer diameter of the first isolation sleeve is D5, and 70%≤D4 / D5≤120%.

[0034] In some embodiments of the present application, the thickness of the first isolation sleeve is L9, 0.5≤L9≤1.5mm.

[0035] In some embodiments of the present application, a rivet hole is further formed on the second conductive member, and an opening direction of the rivet hole is toward a side of the second conductive member away from the battery cell assembly.

[0036] In some embodiments of the present application, an inner chamfer is provided on the edge of the riveting hole, and on any cross section passing through the axis of the riveting hole, an angle between the inner chamfer plane and the second surface is A2, 30°≤A2≤85°.

[0037] In some embodiments of the present application, the diameter of the riveting hole is D6, the minimum outer diameter of the second conductive member is D7, and 30%≤D6 / D7≤80%.

[0038] In some embodiments of the present application, the single cell battery further includes a fastener, the second conductive member includes a through column and a retaining edge, the through column is passed through the conductive hole, the retaining edge abuts against the first conductive member, and the fastener passes through at least one of the first conductive member and the second conductive member and realizes the connection between the first conductive member and the second conductive member.

[0039] In some embodiments of the present application, a first hole is opened on the retaining edge, and the fastener passes through the first hole and is connected to the first conductive member.

[0040] In some embodiments of the present application, a second isolation layer is provided between the first conductive member and the second conductive member.

[0041] In some embodiments of the present application, a third isolation layer is provided on the surface of the fastener that contacts the first conductive member and the second conductive member.

[0042] In some embodiments of the present application, the second isolation layer or the third isolation layer is a nickel plating layer.

[0043] In some embodiments of the present application, the second isolation layer or the third isolation layer is at least one of a PP film or a PPS film.

[0044] In some embodiments of the present application, a distance between a surface of the through-pillar close to the battery cell assembly and a surface of the first conductive member close to the battery cell assembly is H1, and 0.8≤H1≤2mm.

[0045] In some embodiments of the present application, the projection area of ​​the outer edge of the rib on the first conductive member is S6, the contact area between the rib and the first conductive member is S7, and 5%≤S7 / S6≤35%.

[0046] In some embodiments of the present application, there are multiple first holes on each rib.

[0047] In some embodiments of the present application, a plurality of first holes are distributed in a circumferential array on the rib.

[0048] In some embodiments of the present application, the rib abuts against a side of the first conductive member away from the battery cell assembly.

[0049] In some embodiments of the present application, a diameter of the first hole is D8, 2.5 mm ≤ D8 ≤ 16 mm.

[0050] In some embodiments of the present application, a second hole is provided on the first conductive member, and the fastener passes through the first hole and is inserted into the second hole.

[0051] In some embodiments of the present application, the fastener is a screw, and the fastener is threadedly matched with the second hole.

[0052] In some embodiments of the present application, a third hole is opened on the first conductive member, and the fastener passes through the third hole and is connected to the second conductive member.

[0053] In some embodiments of the present application, the fastener includes a first part and a second part that are connected to each other, the first part is passed through the first hole or the third hole, and the second part abuts against a side of the second conductive member away from the first conductive member, or the second part abuts against a side of the first conductive member away from the second conductive member.

[0054] In some embodiments of the present application, the diameter of the first portion is D9, 2.5 mm ≤ D9 ≤ 16 mm.

[0055] In some embodiments of the present application, the thickness of the second portion is L10, 0.5 mm ≤ L10 ≤ 2 mm.

[0056] In some embodiments of the present application, the single cell further includes a second isolation sleeve, the second isolation sleeve is sleeved on the through column, and the first conductive member and the second conductive member at least sandwich a portion of the second isolation sleeve.

[0057] In some embodiments of the present application, the first conductive member includes a plate body and a boss, the conductive hole is opened in the plate body, the boss is protruded from the inner wall of the conductive hole, and the boss and the rib are clamped with a second isolation sleeve.

[0058] In some embodiments of the present application, the height of the boss is H2, 0.5mm<H2≤5mm.

[0059] In some embodiments of the present application, the height of the boss is H2, the thickness of the first conductive member is L11, and 20%≤H2 / L11≤50%.

[0060] In some embodiments of the present application, the height of the boss is H2, the thickness of the first conductive member is L11, the natural length of the second isolation sleeve is L12, and H2+L12>L11.

[0061] In some embodiments of the present application, the second isolation sleeve includes an annular sleeve portion and a gasket portion, the annular sleeve portion is at least partially inserted into the conductive hole, and the gasket portion is at least partially clamped by the retaining edge and the first conductive member.

[0062] In some embodiments of the present application, the outer diameter of the gasket portion is D10, the outer diameter of the rib is D11, and 70%≤D11 / D10≤120%.

[0063] In some embodiments of the present application, the thickness of the gasket portion is L13, 0.5≤L13≤1.5mm.

[0064] In some embodiments of the present application, the second conductive member is inserted into the conductive hole and is snap-connected with the first conductive member.

[0065] In some embodiments of the present application, the first conductive member includes a first surface and a second surface arranged opposite to each other, and the second conductive member includes a base, a connecting rod and a buckle connected in sequence, and the connecting rod is provided with an electrical conductive hole; the base is connected to one end of the connecting rod, and the base abuts against the second surface; the buckle is connected to an end of the connecting rod away from the base, and the buckle is buckled to the first surface.

[0066] In some embodiments of the present application, the outer diameter of the base is D12, 2mm≤D12≤20mm.

[0067] In some embodiments of the present application, the diameter of the conductive hole is D1, the outer diameter of the base is D12, and 130%≤D12 / D1≤200%.

[0068] In some embodiments of the present application, the thickness of the base is L14, 0.2mm≤L14≤2mm.

[0069] In some embodiments of the present application, the outer diameter of the buckle decreases as it moves away from the base.

[0070] In some embodiments of the present application, the diameter of the conductive hole is D1, the maximum outer diameter of the buckle is D13, and 102%≤D13 / D1≤150%.

[0071] In some embodiments of the present application, the diameter of the conductive hole is D1, the minimum outer diameter of the buckle is D14, and 60%≤D14 / D1≤97%.

[0072] In some embodiments of the present application, on any cross section passing through the buckle axis, the angle between the tangent line of the buckle outer contour and the first surface is A3, and 60%≤A3≤85%.

[0073] In some embodiments of the present application, the single cell further includes a second isolation sleeve, the second isolation sleeve is sleeved on the through column, and the first conductive member and the second conductive member at least sandwich a portion of the second isolation sleeve.

[0074] In some embodiments of the present application, the first conductive member includes a plate body and a boss, the conductive hole is opened in the plate body, the boss is protruded from the inner wall of the conductive hole, and a second isolation sleeve is sandwiched between the boss and the base.

[0075] In some embodiments of the present application, the height of the boss is H2, 1mm≤H2≤5mm.

[0076] In some embodiments of the present application, the height of the boss is H2, the thickness of the first conductive member is L11, and 40%≤H2 / L11≤60%.

[0077] In some embodiments of the present application, the height of the boss is H2, the thickness of the first conductive member is L11, the natural length of the second isolation sleeve is L12, and H2+L12≥L11.

[0078] In some embodiments of the present application, the second isolation sleeve includes a ring sleeve portion and a gasket portion, the ring sleeve portion is at least partially inserted into the conductive hole, and the gasket portion is at least partially clamped by the base and the first conductive member.

[0079] In some embodiments of the present application, the outer diameter of the gasket portion is D10, the outer diameter of the base is D12, and 70%≤D12 / D10≤120%.

[0080] In some embodiments of the present application, the thickness of the gasket portion is L13, 0.5≤L13≤1.5mm.

[0081] In some embodiments of the present application, the first conductive member is further formed with a pressure relief groove, and the pressure relief groove is recessed on the surface of the first conductive member to avoid the electrical conductive hole.

[0082] In some embodiments of the present application, the distance between the edge of the pressure relief groove and the edge of the conductive hole is L15, 2mm<L15<35mm.

[0083] In some embodiments of the present application, the maximum width of the pressure relief groove is L16, 0.05mm≤L16≤5mm.

[0084] In some embodiments of the present application, the first conductive member includes a first surface and a second surface that are arranged opposite to each other, the first surface is used to face the battery cell assembly, and the pressure relief groove is opened on the second surface.

[0085] In some embodiments of the present application, the distance between the bottom of the pressure relief groove and the first surface is L17, 0.02mm≤L17≤1.5mm.

[0086] In some embodiments of the present application, the angle between the pressure relief groove and the two groove walls is A4, 20°≤A4≤90°.

[0087] In some embodiments of the present application, the cross-section of the pressure relief groove perpendicular to its extension direction is a trapezoid, and the lower base of the trapezoid is located on the surface of the first conductive member.

[0088] In some embodiments of the present application, the length of the upper base of the trapezoid is L18, 0.02mm≤L18≤3mm.

[0089] In some embodiments of the present application, the bottom of the pressure relief groove has rounded corners.

[0090] In some embodiments of the present application, the radius of the fillet is R1, the maximum width of the pressure relief groove is L16, and 20%≤R1 / L16≤100%.

[0091] In some embodiments of the present application, the single cell further includes a fourth isolation layer, and the fourth isolation layer covers a surface of the first conductive member facing the battery cell assembly.

[0092] In some embodiments of the present application, the fourth isolation layer is a nickel plating layer or an iron alloy plating layer.

[0093] In some embodiments of the present application, the fourth isolation layer is one of a PP film and a PPS.

[0094] In some embodiments of the present application, the area of ​​the first conductive member close to the battery cell assembly is S1, the projection area of ​​the fourth isolation layer on the surface of the first conductive member is S8, and 5%≤S8 / S1≤97%.

[0095] In some embodiments of the present application, the thickness of the fourth isolation layer is L19, 0.05mm≤L19≤2mm.

[0096] In some embodiments of the present application, the thickness of the fourth isolation layer is evenly distributed on the entire surface of the first conductive member.

[0097] In some embodiments of the present application, the thickness of the fourth isolation layer increases as it approaches the conductive hole.

[0098] In some embodiments of the present application, the thickness of the first conductive member is L11, 0.5 mm ≤ L11 ≤ 2 mm.

[0099] In some embodiments of the present application, the single cell battery further includes a shell, one side of the shell is open, the first conductive member blocks the opening of the shell and together with the shell forms an accommodating space, and the battery cell assembly is disposed in the accommodating space.

[0100] In some embodiments of the present application, the single battery further includes a second weld, and the first conductive member and the shell are connected via the second weld.

[0101] In some embodiments of the present application, the height of the second weld protruding from the shell surface is H3, 0mm≤H3≤3mm.

[0102] In some embodiments of the present application, the width of the second weld is L20, 2mm≤L20≤6mm.

[0103] In some embodiments of the present application, the first conductive member includes a first plate, a second plate and a third plate, the conductive hole is opened in the first plate, the third plate is wrapped around the first plate, the shell is connected to the third plate, the opposite ends of the second plate are respectively connected to the first plate and the third plate, and the first plate and the second plate are embedded in the opening of the shell.

[0104] In some embodiments of the present application, the first plate and the second plate are connected by an arc.

[0105] In some embodiments of the present application, the radius of the arc is R2, 0.1mm≤R2≤2mm.

[0106] In some embodiments of the present application, the radius of the arc is R2, the thickness of the first plate is L21, and 20%≤R2 / L21≤100%.

[0107] In some embodiments of the present application, there is an assembly gap between the second plate and the housing.

[0108] In some embodiments of the present application, the width of the assembly gap is L22, 0.1 mm≤L22≤0.5 mm.

[0109] The beneficial effects of the present invention are:

[0110] The second conductive member passes through the conductive hole on the first conductive member, and the second conductive member and the first conductive member are physically connected and conductive at the same time, and the second conductive member and the battery cell assembly are welded and connected. Compared with the prior art, the second conductive member of the present application is less restricted by the structural strength in material selection. Therefore, the first conductive member and the second conductive member of the present application can be configured with different materials. For example, the first conductive member is configured as an aluminum alloy structure commonly used in existing top cover assemblies to ensure the strength of the single cell battery housing; the second conductive member is configured as the same material as the busbar of the battery cell assembly, so that the welding of the second conductive member and the busbar of the battery cell assembly is homogeneous welding, and the weld quality is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0111] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0112] Figure 1 is a schematic diagram of the overall structure of a single cell provided by an embodiment of the present invention;

[0113] Figure 2 is an overall cross-sectional view of a single cell provided by an embodiment of the present invention;

[0114] Figure 3 yes Figure 2 A partial enlarged view of the middle A area;

[0115] Figure 4 is a schematic diagram of the coordination of a second conductive member and a battery cell assembly provided by another embodiment of the present invention;

[0116] Figure 5 is a schematic diagram of the coordination of the second conductive member and the first isolation layer provided by an embodiment of the present invention;

[0117] Figure 6 is a schematic diagram of the coordination of the first conductive member and the second conductive member provided by an embodiment of the present invention;

[0118] Figure 7 is a schematic diagram of the coordination of a first conductive member, a second conductive member and a first isolation sleeve provided by another embodiment of the present invention;

[0119] Figure 8 is an overall cross-sectional view of a single cell provided by another embodiment of the present invention;

[0120] Fig. 9 yes Figure 8 A partial enlarged view of the middle B area;

[0121] Fig.10 yes Fig. 9 A partial enlarged view of the middle C area;

[0122] Fig.11 is a schematic diagram of the coordination of a first conductive member, a second conductive member and a fastener provided by another embodiment of the present invention;

[0123] Fig.12 is a schematic diagram of the coordination of a first conductive member, a second conductive member and a fastener provided by another embodiment of the present invention;

[0124] Fig.13 It is a schematic diagram of the coordination of the first conductive member, the second conductive member, the fastener, and the second isolation sleeve provided by another embodiment of the present invention;

[0125] Fig.14 It is a schematic diagram of the coordination of the first conductive member, the second conductive member, the fastener, and the second isolation sleeve provided by another embodiment of the present invention;

[0126] Fig.15 is an overall cross-sectional view of a single cell provided by another embodiment of the present invention;

[0127] Fig.16 yes Fig.15 A partial enlarged view of the D area in the middle;

[0128] Fig.17 is a schematic diagram of the coordination of a first conductive member and a second conductive member provided by another embodiment of the present invention;

[0129] Fig.18 is a schematic diagram of the coordination of a first conductive member, a second conductive member, and a second isolation sleeve provided by another embodiment of the present invention;

[0130] Fig.19 is a schematic diagram of the coordination of a first conductive member, a second conductive member, and a second isolation sleeve provided by another embodiment of the present invention;

[0131] Fig. 20 yes Figure 2 A partial enlarged view of the middle E area;

[0132] Fig.21 is a schematic diagram of the coordination between the pressure relief groove and the second conductive member provided by another embodiment of the present invention;

[0133] Fig. 22 is a schematic diagram of the coordination between the pressure relief groove and the second conductive member provided by another embodiment of the present invention;

[0134] Fig.23 is a schematic diagram of the coordination of the first conductive member, the second conductive member and the fourth isolation layer provided by an embodiment of the present invention;

[0135] Fig.24 is a schematic diagram of the coordination of a first conductive member, a second conductive member and a fourth isolation layer provided by another embodiment of the present invention;

[0136] Fig.25 It is a schematic diagram of the connection relationship between the first conductive member and the shell provided in an embodiment of the present invention.

[0137] Description of Figure Numbers:

[0138] 10. First conductive member; 11. Plate body; 111. Conductive hole; 112. Second hole; 113. Third hole; 114. Pressure relief groove; 12. Boss; 13. First plate; 14. Second plate; 15. Third plate; 20. Second conductive member; 21. Welding hole; 22. Rivet column; 23. Rivet seat; 24. Rivet buckle; 241. External chamfer; 242. Riveted hole; 243. Internal chamfer; 25. Through column; 26. Sidewall; 261. First hole; 27. Connecting rod; 28. Bottom Seat; 29, buckle; 30, battery cell assembly; 31, battery cell; 311, winding core; 312, pole ear; 32, busbar; 41, first weld; 42, second weld; 51, first isolation layer; 52, second isolation layer; 53, third isolation layer; 54, fourth isolation layer; 55, first isolation sleeve; 56, second isolation sleeve; 561, ring sleeve portion; 562, gasket portion; 60, fastener; 61, first portion; 62, second portion; 70, shell; 80, assembly gap. DETAILED DESCRIPTION

[0139] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0140] In order to solve the technical problems of complex welding parameters and poor weld quality between the shell of a single battery and a battery cell assembly 30 , an embodiment of the present invention provides a single battery, which includes a first conductive member 10 , a second conductive member 20 and a battery cell assembly 30 .

[0141] See also Figures 1 to 3 As shown, Figure 1 is a schematic diagram of the overall structure of a single cell provided by an embodiment of the present invention; Figure 2 is an overall cross-sectional view of a single cell provided by an embodiment of the present invention; Figure 3 yes Figure 2 The above figures together show the matching relationship among the first conductive member 10 , the second conductive member 20 and the battery cell 31 .

[0142] Specifically, the first conductive member 10 is provided with an electrical conductive hole 111, which penetrates the first conductive member 10 in the thickness direction of the first conductive member 10; the second conductive member 20 is provided with an electrical conductive hole 111, and the second conductive member 20 is fixed to and electrically connected to the first conductive member 10; the battery cell assembly 30 is welded to the second conductive member 20.

[0143] In this embodiment, the second conductive member 20 is provided with the conductive hole 111, and the first conductive member 10 and the second conductive member 20 are fixed to each other and electrically connected. Due to the separate design of the first conductive member 10 and the second conductive member 20, the two can be configured with different materials according to needs. Exemplarily, the second conductive member 20 is configured with the same material as the area of ​​the battery cell assembly 30 to which it is welded, so as to optimize the weld performance between the second conductive member 20 and the battery cell assembly 30. At the same time, since the area of ​​the second conductive member 20 on the entire shell accounts for a small proportion, the material adjustment of the second conductive member 20 will not have a significant impact on the structural performance of the single battery shell.

[0144] Compared with the prior art, since the second conductive part 20 can be configured as needed to adapt to the characteristics of the battery cell assembly 30, the single cell battery of this embodiment can significantly optimize the weldability between the shell and the battery cell assembly 30 without significantly affecting the strength of the single cell battery shell, and there is no need to configure complex welding parameters for the dissimilar metals on both sides. This improves the weld strength and conductivity, simplifies the production process, optimizes the single cell battery performance and extends the service life of the single cell battery.

[0145] In some embodiments of the present application, a welding hole 21 is further formed on the second conductive member 20 , and an opening direction of the welding hole 21 is toward a side of the second conductive member 20 away from the battery cell assembly 30 .

[0146] For the sake of clarity, the processing steps of a single cell are explained here. Normally, during the processing of a single cell, in order to achieve welding between the outer shell and the battery cell assembly 30, the conductive area of ​​the battery cell assembly 30 is abutted against the outer shell from the inside of the outer shell, and then the welding gun is aimed at the corresponding area on the outside of the outer shell, and the conductive area of ​​the battery cell assembly 30 and the abutting area of ​​the outer shell are melted through the outer shell by applying voltage and high temperature, and a weld is formed after the molten metal solidifies.

[0147] Because the above welding process needs to be melted across the outer shell, the thickness of the outer shell determines the power requirement and weld penetration of the welding. In this embodiment, the second conductive member 20 is welded to the battery cell assembly 30. Therefore, the smaller the distance between the outer surface and the inner surface of the welding area of ​​the second conductive member 20, the easier it is to weld. Providing a welding hole 21 on the second conductive member 20 allows the welding gun to be closer to the area where the battery cell assembly 30 and the second conductive member 20 are connected. On the one hand, this reduces the loss during energy transmission, and on the other hand, it also avoids overburning of the second conductive member 20 during welding, effectively ensuring that the second conductive member 20 still retains good electrical and mechanical properties after welding.

[0148] Furthermore, the diameter of the conductive hole 111 is D1, the diameter of the welding hole 21 is D2, and 30%≤D2 / D1≤90%.

[0149] The diameter of the welding hole 21 is limited by the diameter of the conductive hole 111. A larger welding hole 21 allows a larger welding gun to be inserted into the welding hole 21 for welding. However, if the size of the conductive hole 111 is determined, an overly large welding hole 21 will make the wall thickness of the second conductive member 20 where the welding hole 21 is opened too thin, affecting the strength and current carrying capacity of the second conductive member 20. The selection of the value of 30%≤D2 / D1≤90% can make the welding hole 21 as easy as possible for the welding gun to be inserted while ensuring the strength and current carrying capacity of the second conductive member 20.

[0150] Optionally, the depth of the welding hole 21 is L1, the projection length of the second conductive member 20 in the thickness direction of the first conductive member 10 is L2, and 50%≤L1 / L2≤90%.

[0151] The depth of the welding hole 21 is limited by the second conductive member 20. A too shallow welding hole 21 requires the welding current or heat energy to penetrate the thicker bottom of the second conductive member 20, which wastes energy and destroys the crystal structure of the second conductive member 20. A too deep welding hole 21 makes the bottom of the second conductive member 20 too thin, which may cause the risk of overheating or even burning through during welding. The value selection of 50%≤L1 / L2≤90% can make the thickness of the bottom of the second conductive member 20 suitable for the welding process.

[0152] It should be noted that the thickness direction mentioned in this embodiment does not mean that the size of the first conductive member 10 in this direction must be smaller than its diameter. The description here only represents that in most existing single cells, the thickness direction is the direction in which the first conductive member 10 is buckled with the housing 70. All the size descriptions involved below are only general descriptions of the technical field without additional restrictions, and do not mean that there are no special cases. The specific references should be based on the marks in the corresponding drawings.

[0153] Optionally, the minimum distance between the hole wall of the welding hole 21 and the outer wall of the second conductive member 20 is L3, and L3 is ≥ 0.05 mm.

[0154] The welding hole 21 is preferably coaxially arranged with the second conductive part 20, but considering the processing accuracy and assembly concessions, there are also application scenarios in which the two are eccentrically arranged. Limiting L3 ≥ 0.05 mm can effectively prevent the distance between the hole wall of the welding hole 21 and the outer wall of the second conductive part 20 from being too close, thereby avoiding breakdown of the second conductive part 20 due to insufficient current carrying capacity during the subsequent use of the single cell.

[0155] Optionally, the distance between the bottom of the welding hole 21 and the surface of the second conductive member 20 on one side close to the battery cell assembly 30 is L4, and 0.05 mm ≤ L4 ≤ 2 mm.

[0156] The size of the second conductive member 20 changes with the capacity and design of the single battery, but the bottom thickness of the second conductive member 20 that carries the welding current and heat, that is, the distance between the bottom of the welding hole 21 and the surface of the second conductive member 20 close to the battery cell assembly 30, is limited by the welding process and has a specific range of parameters, which will not be significantly changed by the change of the second conductive member 20. Calculations show that the value range of 0.05mm≤L4≤2mm can prevent the bottom of the second conductive member 20 that is too thin from being burned through, and can also prevent energy waste caused by an overly thick bottom, which is a better parameter configuration.

[0157] In some embodiments of the present application, the battery cell assembly 30 includes a battery cell 31 and a busbar 32 , and the busbar 32 is electrically connected to the battery cell 31 and the second conductive member 20 , respectively.

[0158] The busbar 32 can collect the current of the entire battery cell 31. The second conductive member 20 and the busbar 32 are welded, and the current of the battery cell 31 is conducted to the first conductive member 10 via the busbar 32 and the second conductive member 20. During the entire current transmission process, the original largest resistance segment is greatly optimized because the second conductive member 20 and the busbar 32 are welded, thereby improving the energy efficiency of the single battery.

[0159] Furthermore, the area of ​​the first conductive member 10 close to the battery cell assembly 30 is S1, the projected area of ​​the contact surface between the second conductive member 20 and the busbar 32 on the first conductive member 10 is S2, and 20%≤S2 / S1≤90%.

[0160] The larger the contact area between the second conductive member 20 and the busbar 32, the stronger the flow conductivity between the two. However, this positive correlation has a limit due to the area of ​​the busbar 32. 20% ≤ S2 / S1 ≤ 90% is a numerical range that can obtain more intuitive performance optimization from the increase in the area of ​​the busbar 32 and the second conductive member 20.

[0161] It should be noted that the projection area here refers to the area of ​​the largest figure that can be enclosed by the projection of the structure on the corresponding plane. For structures with holes inside, the projection area should be enclosed by the outer edge of the projection figure.

[0162] Optionally, the second conductive member 20 is connected to the busbar 32 via a first weld 41, a projection area of ​​the first weld 41 on the surface of the busbar 32 is S3, a surface area of ​​the busbar 32 close to the first conductive member 10 is S4, and S3 / S4 ≥ 10%.

[0163] The larger the proportion of the first weld 41, the more stable the connection between the busbar 32 and the second conductive member 20. In particular, in the technical solution that requires stabilizing the position of the battery cell assembly 30 by the first weld 41, the cross-sectional area of ​​the first weld 41 is directly related to whether the battery cell assembly 30 can maintain the connection with the second conductive member 20. S3 / S4≥10% is the preferred numerical range for maintaining the connection between the second conductive member 20 and the busbar 32.

[0164] Optionally, the second conductive member 20 is welded to a side of the busbar 32 close to the first conductive member 10 , and a side of the busbar 32 away from the second conductive member 20 is electrically connected to the battery cell 31 .

[0165] The two sides of the busbar 32 are electrically connected to the second conductive member 20 and the battery cell 31 respectively, so that the surface area of ​​the busbar 32 can be fully utilized as much as possible to increase the flow area and current carrying capacity.

[0166] Optionally, the second conductive member 20 and the busbar 32 are made of the same material.

[0167] The second conductive member 20 and the busbar 32 made of the same material have similar welding parameters and fluidity, and the effect of homogeneous welding is better.

[0168] Please also read Figure 4 As shown, Figure 4 It is a schematic diagram of the coordination between the second conductive member and the battery cell assembly provided in another embodiment of the present invention.

[0169] In some embodiments of the present application, the battery cell assembly 30 includes a winding core 311 and a tab 312 that are electrically connected, and the tab 312 is welded to the second conductive member 20 .

[0170] This embodiment provides another technical solution. In the technical solution in which the busbar 32 is not provided, the second conductive member 20 can also be directly electrically connected to the battery cell 31. Specifically, the battery cell 31 includes a winding core 311 and a pole tab 312, and the second conductive member 20 and the pole tab 312 are welded and connected.

[0171] Furthermore, the second conductive member 20 and the tab 312 are made of the same material.

[0172] Similar to the busbar 32 , the second conductive member 20 and the tab 312 made of the same material have similar welding parameters and fluidity, and the effect of homogeneous welding is better.

[0173] In some embodiments of the present application, there are multiple conductive holes 111 , and the second conductive members 20 are disposed corresponding to the conductive holes 111 one by one.

[0174] The plurality of conductive holes 111 can disperse the current-carrying area, thereby achieving a better current-carrying effect while keeping the total flow area unchanged.

[0175] Furthermore, a plurality of conductive holes 111 are formed in a circumferential array on the first conductive member 10 .

[0176] On one hand, the conductive holes 111 formed in a circumferential array can make the current distribution more uniform and optimize the electrical performance of the single cell. On the other hand, the conductive holes 111 formed in a circumferential array can also minimize the damage to the mechanical performance of the single cell caused by opening holes in the first conductive member 10.

[0177] In some embodiments of the present application, the material of the second conductive member 20 includes copper.

[0178] The existing battery cell assembly 30, whether it is the type that outputs directly to the outside through the pole ear 312 or the type that outputs after convergence through the busbar 32, the material of the output end is mostly made of copper. The material of the second conductive member 20 includes copper, which can enhance the welding matching degree between the second conductive member 20 and the battery cell assembly 30, simplify the welding process, and optimize the weld performance.

[0179] It should be noted that in this embodiment, the busbar 32 and the pole lug 312 are described as output ends. In a considerable number of battery cell assemblies 30, the busbar 32 and the pole lug 312 both assume the function of current input. The description here only expresses that during the use of the single battery, the busbar 32 and the pole lug 312 assume the output function, and does not limit them to only output. The protection scope of this application cannot be limited to this. The output of the following embodiments is also understood in this way.

[0180] Please also read Figure 5 As shown, Figure 5 It is a schematic diagram of the coordination of the second conductive member and the first isolation layer provided in an embodiment of the present invention.

[0181] Furthermore, the single battery cell further includes a first isolation layer 51 , which wraps the second conductive member 20 , and a side of the second conductive member 20 close to the battery cell assembly 30 is at least partially exposed.

[0182] In the actual processing, the second conductive member 20 and the battery cell assembly 30 are only welded at the abutting part. Therefore, when the welding area is exposed, setting the first isolation layer 51 to protect other areas of the second conductive member 20 is an effective method to extend the service life of the second conductive member 20. In the actual operation of the single battery, because the first conductive member 10 and the second conductive member 20 are dissimilar metals, the connection area between the two immersed in the electrolyte will produce a certain amount of electrochemical corrosion. Using the first isolation layer 51 to isolate the first conductive member 10 and the second conductive member 20 can effectively reduce the corrosion rate of the joint between the two.

[0183] Furthermore, the material of the first isolation layer 51 includes at least one of steel and nickel.

[0184] On the one hand, steel and nickel are also commonly used materials for the first conductive member 10. Therefore, electrochemical corrosion is unlikely to occur between the first insulating layer 51 and the first conductive member 10 that are in direct contact. On the other hand, the joint between the first insulating layer 51 and the second conductive member 20 is closed between the second conductive member 20 and the battery cell assembly 30. It is difficult for the electrolyte to enter, and there is no environment for electrochemical corrosion. Therefore, electrochemical corrosion is unlikely to occur.

[0185] Optionally, the area of ​​the exposed portion of the second conductive member 20 close to the battery cell assembly 30 is S5, the area of ​​the first conductive member 10 close to the battery cell assembly 30 is S1, and 40%≤S5 / S1≤100%.

[0186] Sufficient exposed area of ​​the second conductive member 20 is a prerequisite for ensuring good weldability and current carrying capacity between the second conductive member 20 and the battery cell assembly 30. When S5 / S1 is less than 40%, the welding effect will be significantly affected. The preferred value of S5 / S1 is 70% or 80%.

[0187] Please also read Figure 6 As shown, Figure 6 It is a schematic diagram of the coordination of the first conductive member and the second conductive member provided in an embodiment of the present invention.

[0188] In some embodiments of the present application, the second conductive member 20 and the first conductive member 10 are fixed by riveting.

[0189] Riveting fixation is one of the commonly used processing techniques, that is, using a riveting machine to partially deform and expand the second conductive member 20 that passes through the conductive hole 111 and clamp the edge of the conductive hole 111. The second conductive member 20 and the first conductive member 10 are riveted and fixed, which can achieve a good connection effect between the first conductive member 10 and the second conductive member 20 while having higher productivity.

[0190] Furthermore, the first conductive member 10 includes a first surface and a second surface relative to each other, and the second conductive member 20 includes a rivet seat 23, a rivet column 22 and a rivet buckle 24 connected in sequence. Specifically, the rivet column 22 is provided with an electrical conductive hole 111; the rivet seat 23 is connected to one end of the rivet column 22, and the rivet seat 23 abuts against the first surface; the rivet buckle 24 is connected to one end of the rivet column 22 away from the rivet seat 23, and the rivet buckle 24 is riveted to the second surface.

[0191] The rivet seat 23 abuts against the first surface, and the rivet button 24 abuts against the second surface. The formation of the rivet button 24 depends on the deformation caused by the riveting machine stamping. The length of the rivet column 22 depends on the deformation of the rivet button 24 during the riveting process. Therefore, the rivet column 22 can adapt to the thickness of the first conductive member 10, so that the rivet seat 23 and the rivet button 24 can better clamp the first conductive member 10.

[0192] Furthermore, an outer edge of one end of the rivet button 24 away from the rivet seat 23 is provided with an outer chamfer 241 , and on any cross section passing through the axis of the rivet button 24 , an angle A1 is formed between the outer chamfer 241 and the second surface, and 10°≤A1≤85°.

[0193] The setting of the outer chamfer 241 can effectively prevent the rivet 24 from being scratched and damaged by other parts. An excessively large A1 will lead to the formation of new ridges, making the outer chamfer 241 meaningless, while an excessively small A1 will lead to the rivet 24 extending a long distance outward to absorb the thickness of the rivet 24. The selection of a value of 10°≤A1≤85° is conducive to structural design and can also be adapted to existing riveting machines. The preferred value of A1 is 45°, 48° or 54°.

[0194] Specifically, the distance between the outer edge of the outer chamfer 241 and the second surface is L5, the thickness of the rivet 24 is L6, and 0≤L5 / L6≤70%.

[0195] If the distance between the outer edge of the outer chamfer 241 and the second surface is too thick, it will affect the appearance of the single battery and increase the risk of damage caused by collision of the single batteries in the battery pack. 0≤L5 / L6≤70% is a better numerical choice, and L5 / L6 is most preferably 0%, that is, the outer edge of the outer chamfer 241 directly fits the surface of the first conductive part 10.

[0196] Optionally, the thickness of the rivet buckle 24 is L6, the projection length of the second conductive member 20 in the thickness direction of the rivet buckle 24 is L7, and 10%≤L6 / L7≤40%.

[0197] Although the thickness of the rivet button 24 will change due to the thickness of the material it rivets, the thickness of the rivet button 24 itself still has a certain reference value. A too small size of the rivet button 24 may cause the rivet button 24 to fall off the rivet column 22, resulting in failure of the connection between the first conductive member 10 and the second conductive member 20. A too large size of the rivet button 24 indicates that there is a defect in the selection of the riveting size, resulting in a large waste of materials and an increase in the redundant weight of the single battery. 10%≤L6 / L7≤40% can ensure the connection effect of the first conductive member 10 and the second conductive member 20 while saving materials as much as possible. The preferred values ​​of L6 / L7 are 20%, 23%, and 25%.

[0198] Optionally, the diameter of the conductive hole 111 is D1, the outer diameter of the rivet button 24 is D3, and 120%≤D3 / D1≤200%.

[0199] The outer diameter of the rivet buckle 24 determines the riveting strength. Under the premise that the size of the conductive hole 111 is fixed, the larger the outer diameter of the rivet buckle 24, the better the riveting effect. Correspondingly, an oversized rivet buckle 24 will cause space occupation and material waste. 120% ≤ D3 / D1 ≤ 200% is a choice to save materials as much as possible while ensuring the riveting strength. Under the premise that the processing accuracy allows, D3 / D1 is preferably 128% or 130%.

[0200] Optionally, the diameter of the rivet seat 23 is D4, 2mm≤D4≤20mm.

[0201] The diameter of the rivet seat 23 determines the pressure bearing capacity of the second conductive member 20 during the riveting process, which is not affected by the conductive hole 111. An oversized rivet seat 23 will undoubtedly occupy extra space. Therefore, 2mm≤D4≤20mm can save space as much as possible to avoid the rivet seat 23 being damaged by the riveting process. D4 is preferably 4mm, 6mm and 8mm.

[0202] Optionally, the diameter of the conductive hole 111 is D1, the diameter of the rivet seat 23 is D4, and 130%≤D4 / D1≤200%.

[0203] The selection of the rivet seat 23 should also refer to the conductive hole 111. When the rivet seat 23 is too small, there is a risk that the rivet seat 23 will be directly inserted into the conductive hole 111 due to interference fit with the conductive hole 111, and if the rivet seat 23 is too large, it will occupy extra space. 130%≤D4 / D1≤200% is the preferred solution. Under the premise that the processing accuracy allows, D4 / D1 is preferably 130%, 132%, or 135%.

[0204] Optionally, the thickness of the rivet seat 23 is L8, 0.05mm≤L8≤2mm.

[0205] The thickness of the rivet seat 23 also affects the pressure bearing capacity during the riveting process. A too thin rivet seat 23 is easily broken during the riveting process, while an overly large rivet seat 23 will occupy extra space. Therefore, 0.05mm≤L8≤2mm can save space as much as possible to avoid the rivet seat 23 being damaged by the riveting process. L8 is preferably 0.1mm, 0.5mm and 1mm.

[0206] Please also read Figure 7 As shown, Figure 7 It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20 and the first isolation sleeve 55 provided in another embodiment of the present invention.

[0207] Optionally, the single cell further includes a first isolation sleeve 55 , the rivet column 22 passes through the first isolation sleeve 55 , and the rivet seat 23 and the first surface clamp the first isolation sleeve 55 .

[0208] The first isolation sleeve 55 is provided to separate the rivet seat 23 and the first surface, thereby preventing the first conductive member 10 and the second conductive member 20 from being electrochemically corroded due to being immersed in the electrolyte and in direct contact. In addition, the first isolation sleeve 55 is sandwiched between the rivet seat 23 and the first surface. During the riveting process, the first isolation sleeve 55 will be slightly deformed to adapt to the rivet seat 23 and the first surface, which can effectively increase the air tightness at the conductive hole 111.

[0209] Specifically, the diameter of the rivet seat 23 is D4, the outer diameter of the first isolation sleeve 55 is D5, and 70%≤D4 / D5≤120%.

[0210] The diameter of the rivet seat 23 should be as close as possible to the outer diameter of the first isolation sleeve 55. If the size difference between the two is too large, redundant structures will be generated, affecting the space utilization of the single battery and increasing the additional production cost. 70% ≤ D4 / D5 ≤ 120%. Under the premise that the processing accuracy allows, D4 / D5 can be selected as 95%, 98% or 100%. D4 ≤ D5 can avoid electrochemical corrosion caused by the rivet seat 23 and the first surface facing each other.

[0211] Specifically, the thickness of the first isolation sleeve 55 is L9, 0.5≤L9≤1.5 mm.

[0212] The thickness of the first isolation sleeve 55 is an important parameter that affects its insulation and sealing performance. A first isolation sleeve 55 that is too thin cannot be well sealed and is easily squeezed and damaged during riveting. A first isolation sleeve 55 that is too thick will take up extra space and affect the space utilization of the single battery.

[0213] In some embodiments of the present application, a rivet hole 242 is further formed on the riveted second conductive member 20 , and the opening direction of the rivet hole 242 is toward a side of the second conductive member 20 away from the battery cell assembly 30 .

[0214] The provision of the riveting hole 242 facilitates the insertion of the riveting machine punch and also facilitates the rivet buckle 24 to be rolled around, thereby reducing the risk of the second conductive member 20 being damaged due to the riveting process.

[0215] Furthermore, an inner chamfer 243 is provided at the edge of the rivet hole 242 , and on any cross section passing through the axis of the rivet hole 242 , the included angle between the plane of the inner chamfer 243 and the second surface is A2, 30°≤A2≤85°.

[0216] The setting of the inner chamfer 243 is beneficial to guiding the alignment of the riveting machine punch and the riveting hole 242. If A2 is too large, the outer edge of the inner chamfer 243 will be too narrow and the guiding effect will be insufficient. If A2 is too small, the punch and the inner chamfer 243 will collide and guidance will be impossible. 30°≤A2≤85° can ensure a better guiding effect. The most preferred A2 is 40°, 45°, and 48°.

[0217] Optionally, the diameter of the riveting hole 242 is D6, the minimum outer diameter of the second conductive member 20 is D7, and 30%≤D6 / D7≤80%.

[0218] The diameter of the rivet hole 242 is limited by the outer diameter of the second conductive member 20. A larger rivet hole 242 makes the hole wall of the rivet hole 242 thinner, making the riveting process easier to perform. However, an oversized rivet hole 242 will make the wall thickness of the second conductive member 20 where the rivet hole 242 is opened too thin, affecting the strength and current carrying capacity of the second conductive member 20. The value selection of 30%≤D6 / D7≤80% can make the riveting process as easy as possible while ensuring the strength and current carrying capacity of the second conductive member 20. The most preferred value of D6 / D7 is 40% or 50%.

[0219] Please also read Figure 8 and Fig. 9 As shown, Figure 8 is an overall cross-sectional view of a single cell provided by another embodiment of the present invention; Fig. 9 yes Figure 8 A partial enlarged view of area B.

[0220] In some embodiments of the present application, the single cell further includes a fastener 60, the second conductive member 20 includes a through column 25 and a retaining edge 26, the through column 25 is passed through the conductive hole 111, the retaining edge 26 abuts against the first conductive member 10, and the fastener 60 passes through at least one of the first conductive member 10 and the second conductive member 20 and realizes the connection between the first conductive member 10 and the second conductive member 20.

[0221] Different from riveting, the second conductive member 20 of this embodiment only needs to abut against the first conductive member 10 on one side surface thereof, which is more flexible in assembly and also convenient for designing the structure on the other side of the first conductive member 10 opposite to the abutment point.

[0222] Furthermore, a first hole 261 is formed on the retaining edge 26 , and the fastener 60 passes through the first hole 261 and is connected to the first conductive member 10 .

[0223] On one hand, the fastener 60 is connected to the first conductive member 10 , and on the other hand, the fastener 60 passes through the first hole 261 . As the fastener 60 is fixed, the first conductive member 10 and the second conductive member 20 are fastened, thereby optimizing the connection effect and air tightness of the first conductive member 10 and the second conductive member 20 .

[0224] Please also read Fig.10 As shown, Fig.10 yes Fig. 9 A partial enlarged view of the middle C area.

[0225] Furthermore, a second isolation layer 52 is disposed between the first conductive member 10 and the second conductive member 20 .

[0226] The second isolation layer 52 is provided to at least partially isolate the first conductive member 10 and the second conductive member 20 , thereby preventing electrochemical corrosion caused by direct exposure of the first conductive member 10 and the second conductive member 20 .

[0227] Optionally, a third isolation layer 53 is provided on the surface of the fastener 60 that contacts the first conductive member 10 and the second conductive member 20 .

[0228] The third isolation layer 53 protects the fastener 60 and prevents the fastener 60 from being worn during the fastening process, thereby preventing the fastening effect from being affected.

[0229] Specifically, the second isolation layer 52 or the third isolation layer 53 is a nickel plating layer.

[0230] The nickel plating layer can achieve conductivity while providing protection, and is particularly beneficial for fully encapsulating protection of the first conductive member 10 .

[0231] Specifically, the second isolation layer 52 or the third isolation layer 53 is at least one of a PP film and a PPS film.

[0232] PP film and PPS film are relatively mature protective materials in the lithium battery field, with low cost and high processing efficiency.

[0233] Optionally, a distance between a surface of the through-pillar 25 close to the battery cell assembly 30 and a surface of the first conductive member 10 close to the battery cell assembly 30 is H1, and 0.8≤H1≤2mm.

[0234] The distance between the surface of the through-pillar 25 close to the cell assembly 30 and the surface of the first conductive member 10 close to the cell assembly 30, that is, the height of the through-pillar 25 protruding from the first conductive surface, when H1 is too large, there will be a large gap between the cell assembly 30 and the first conductive member 10, and when H2 is too small, there will be a risk of short circuit between the first conductive member 10 and the cell assembly 30, affecting the safety of the single cell. 0.8≤H1≤2mm can maximize the space utilization rate in the single cell while ensuring safety. Under the premise of production accuracy, H1 is preferably 8mm, 9mm, 10mm.

[0235] Optionally, a projection area of ​​an outer edge of the rib 26 on the first conductive member 10 is S6, a contact area between the rib 26 and the first conductive member 10 is S7, and 5%≤S7 / S6≤35%.

[0236] The contact area between the retaining edge 26 and the first conductive member 10 affects the connection strength and current carrying capacity of the first conductive member 10 and the second conductive member 20. 5%≤S7 / S6≤35% can enhance the connection strength and current carrying capacity of the first conductive member 10 and the second conductive member 20 as much as possible under the premise that the size of the second conductive member 20 is fixed. S7 / S6 is preferably 20% or 30%.

[0237] Please also read Fig.11 As shown, Fig.11 It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20 and the fastener 60 provided in another embodiment of the present invention.

[0238] Optionally, there are multiple first holes 261 on each rib 26 .

[0239] The plurality of first holes 261 can disperse the load, thereby achieving a better fixing effect while keeping the total cross-sectional area of ​​the fastener 60 unchanged.

[0240] Furthermore, a plurality of first holes 261 are distributed in a circumferential array on the rib 26 .

[0241] On the one hand, the first holes 261 opened in the circular array can make the force of the fastener 60 more uniform and enhance the connection strength between the first conductive member 10 and the second conductive member 20. On the other hand, the first holes 261 distributed in the circular array can also minimize the damage to the mechanical properties of the second conductive member 20 caused by opening holes in the retaining edge 26.

[0242] Optionally, the retaining edge 26 abuts against a side of the first conductive member 10 away from the battery cell assembly 30 .

[0243] The retaining edge 26 of the second conductive member 20 abuts against the side of the first conductive member 10 away from the battery cell assembly 30, that is, the second conductive member 20 is inserted from the outside of the single battery cell and can be installed last after the first conductive member 10, the battery cell assembly 30 and other structures are assembled in place. The second conductive member 20 is inserted and connected to the first conductive member 10 and abuts against the battery cell assembly 30 at the same time.

[0244] Optionally, a diameter of the first hole 261 is D8, 2.5 mm ≤ D8 ≤ 16 mm.

[0245] The diameter of the first hole 261 should be set to fit the fastener 60 , and 2.5 mm ≤ D8 ≤ 16 mm can fit fasteners 60 of common sizes. The first hole 261 is preferably 2.5 mm and 16 mm.

[0246] Optionally, the first conductive member 10 is provided with a second hole 112 , and the fastener 60 passes through the first hole 261 and is inserted into the second hole 112 .

[0247] The perforations on the retaining edge 26 do not affect the air tightness of the single cell. The fastener 60 passes through the first hole 261 and is inserted into the second hole 112, so that the connection can be achieved without affecting the air tightness of the single cell.

[0248] Specifically, the fastener 60 is a screw, and the fastener 60 is threadedly matched with the second hole 112 .

[0249] The fastener 60 is selected as a screw, the parts cost is low, the production line technology is mature, and the production efficiency is high.

[0250] Please also read Fig.12 As shown, Fig.12 It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20 and the fastener 60 provided in another embodiment of the present invention.

[0251] In some embodiments of the present application, a third hole 113 is formed on the first conductive member 10 , and the fastener 60 passes through the third hole 113 and is connected to the second conductive member 20 .

[0252] This embodiment provides another fastening method of the first conductive member 10 and the second conductive member 20 .

[0253] In some embodiments of the present application, the fastener 60 includes a first part 61 and a second part 62 that are connected to each other, the first part 61 is passed through the first hole 261 or the third hole 113, and the second part 62 abuts against a side of the second conductive member 20 away from the first conductive member 10, or the second part 62 abuts against a side of the first conductive member 10 away from the second conductive member 20.

[0254] The second portion 62 abuts against the first conductive member 10 or the second conductive member 20 . When the fastener 60 is removed, the abutting surface still maintains the original structure, thereby reducing damage to the parts.

[0255] Specifically, the diameter of the first portion 61 is D9, 2.5 mm ≤ D9 ≤ 16 mm.

[0256] Under the premise of meeting the strength requirement, the diameter of the first part 61 is selected from the commonly used part size range of 2.5mm≤D9≤16mm to reduce the production cost, and D9 is preferably 2.5mm and 16mm.

[0257] Specifically, the thickness of the second portion 62 is L10, 0.5 mm ≤ L10 ≤ 2 mm.

[0258] The thickness of the second portion 62 affects the pressure bearing capacity during the fastening process. A second portion 62 that is too thin is easily broken during the fastening process, while a second portion 62 that is too large will occupy extra space. Therefore, 0.5 mm ≤ L10 ≤ 2 mm can save space as much as possible to avoid the second portion 62 being damaged by the fastening process. L10 is preferably 0.5 mm and 1 mm.

[0259] In some embodiments of the present application, the single cell further includes a second isolation sleeve 56 , which is sleeved on the through-post 25 , and the first conductive member 10 and the second conductive member 20 at least partially sandwich the second isolation sleeve 56 .

[0260] The second isolation sleeve 56 enhances the air tightness at the conductive hole 111. Due to the clamping of the first conductive member 10 and the second conductive member 20, the second isolation sleeve 56 can undergo adaptive slight deformation according to the surfaces of the two, further filling the surface defects of the parts that may damage the air tightness.

[0261] Please also read Fig.13 As shown, Fig.13 It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20, the fastener 60, and the second isolation sleeve 56 provided in another embodiment of the present invention.

[0262] Furthermore, the first conductive member 10 includes a plate body 11 and a boss 12 . The conductive hole 111 is opened in the plate body 11 . The boss 12 is protruded from the inner wall of the conductive hole 111 . The boss 12 and the rib 26 sandwich a second isolation sleeve 56 .

[0263] The second isolation sleeve 56 is sandwiched between the second conductive member 20 and the boss 12, which can better position the second isolation member and prevent the second isolation member from being pushed out of the conductive hole 111 during the insertion of the second conductive member 20, thereby affecting the assembly effect and sealing ability.

[0264] Furthermore, the height of the boss 12 is H2, 0.5 mm<H2≤5 mm.

[0265] The height of the boss 12 affects the bearing capacity of the boss 12. If the height of the boss 12 is too small, there is a risk of being crushed by the second conductive member 20. If the height of the boss 12 is too large, the space for placing the second isolation member is too small, affecting the sealing effect. 0.5mm<H2≤5mm is the choice to minimize the space occupied by the boss 12 while ensuring the strength of the boss 12.

[0266] Optionally, the height of the boss 12 is H2, the thickness of the first conductive member 10 is L11, and 20%≤H2 / L11≤50%.

[0267] The height of the boss 12 is also affected by the thickness of the first conductive part 10. In actual production, in addition to ensuring its own strength, the height of the boss 12 also needs to consider the thickness of the first conductive part 10. 20%≤H2 / L11≤50% can provide as much space as possible for the second isolation part while ensuring the strength of the boss 12 itself.

[0268] Optionally, the height of the boss 12 is H2, the thickness of the first conductive member 10 is L11, the natural length of the second isolation sleeve 56 is L12, and H2+L12>L11.

[0269] The sum of the height of the boss 12 and the natural length of the second isolation sleeve 56 is greater than the thickness of the first conductive member 10, that is, when the second conductive member 20 is inserted into the conductive hole 111 and assembled in place, the second isolation sleeve 56 is squeezed, the length becomes shorter, and the thickness increases, so that the sealing effect is better.

[0270] Please also read Fig.14 As shown, Fig.14 It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20, the fastener 60, and the second isolation sleeve 56 provided in another embodiment of the present invention.

[0271] Optionally, the second isolation sleeve 56 includes a ring sleeve portion 561 and a gasket portion 562 , the ring sleeve portion 561 is at least partially inserted into the conductive hole 111 , and the gasket portion 562 is at least partially sandwiched by the retaining edge 26 and the first conductive member 10 .

[0272] The gasket portion 562 of the second isolation sleeve 56 is sandwiched between the second conductive member 20 and the first conductive member 10 , so that the position of the second isolation sleeve 56 is fixed by the edge of the conductive hole 111 , thereby preventing the second isolation sleeve 56 from sliding into the conductive hole 111 and causing assembly errors.

[0273] Furthermore, the outer diameter of the gasket portion 562 is D10, the outer diameter of the rib 26 is D11, and 70%≤D11 / D10≤120%.

[0274] The diameter of the gasket portion 562 should be as close as possible to the outer diameter of the retaining edge 26. If the difference between the two sizes is too large, a redundant structure will be generated, which will increase the additional production cost. 70%≤D11 / D10≤120%. Under the premise of machining accuracy, D11 / D10 can be 98%, 100% or 102%.

[0275] Optionally, the thickness of the gasket portion 562 is L13, 0.5≤L13≤1.5 mm.

[0276] The thickness of the gasket portion 562 is an important parameter that affects the insulation and sealing performance of the second isolation sleeve 56. A gasket portion 562 that is too thin cannot be well sealed and is easily squeezed and damaged during tightening. A second isolation sleeve 56 that is too thick will take up extra space and affect the space utilization of the single battery.

[0277] Please also read Fig.15 and Fig.16 As shown, Fig.15 is an overall cross-sectional view of a single cell provided by another embodiment of the present invention, Fig.16 yes Fig.15 A partial enlarged view of the D area in the middle.

[0278] In some embodiments of the present application, the second conductive member 20 is inserted into the conductive hole 111 and is snap-connected with the first conductive member 10 .

[0279] The second conductive member 20 is snap-connected with the first conductive member 10 , that is, the part of the second conductive member 20 with an outer diameter larger than the conductive hole 111 is squeezed out of the conductive hole 111 and snap-connected with the other end of the conductive hole 111 . The assembly process is mature and the production efficiency is high.

[0280] Specifically, the first conductive member 10 includes a first surface and a second surface that are relatively arranged, and the second conductive member 20 includes a base 28, a connecting rod 27 and a buckle 29 that are connected in sequence, and the connecting rod 27 is penetrated by an electrical conductive hole 111; the base 28 is connected to one end of the connecting rod 27, and the base 28 abuts against the second surface; the buckle 29 is connected to one end of the connecting rod 27 away from the base 28, and the buckle 29 is buckled into the first surface.

[0281] The buckle 29 is clamped on the first surface to fix the second conductive member 20 on the first surface. The base 28 abuts against the second surface to prevent the second conductive member 20 from sliding into the conductive hole 111 or squeezing the battery cell assembly 30 .

[0282] Furthermore, the outer diameter of the base 28 is D12, 2mm≤D12≤20mm.

[0283] The diameter of the base 28 determines the pressure bearing capacity of the second conductive member 20 during the clamping process, which is not affected by the conductive hole 111. An oversized base 28 will undoubtedly occupy extra space. Therefore, 2mm≤D12≤20mm can save space as much as possible to avoid the base 28 being damaged by the clamping process. D12 is preferably 4mm, 6mm and 8mm.

[0284] Optionally, the diameter of the conductive hole 111 is D1, the outer diameter of the base 28 is D12, and 130%≤D12 / D1≤200%.

[0285] The selection of the base 28 should also refer to the conductive hole 111. When the base 28 is too small, there is a risk that the base 28 will be directly inserted into the conductive hole 111 due to interference fit. If the base 28 is too large, it will occupy extra space. 130%≤D12 / D1≤200% is the preferred solution. Under the premise that the processing accuracy allows, D12 / D1 is preferably 130%, 132%, or 135%.

[0286] Optionally, the thickness of the base 28 is L14, 0.2 mm≤L14≤2 mm.

[0287] The thickness of the base 28 also affects the pressure bearing capacity during the clamping process. A base 28 that is too thin is easily broken during the clamping process, while a base 28 that is too large will take up extra space. Therefore, 0.2mm≤L14≤2mm can save space as much as possible to avoid the base 28 being damaged by the clamping process. L14 is preferably 0.5mm and 1mm.

[0288] Please also read Fig.17 As shown, Fig.17 It is a schematic diagram of the cooperation between the first conductive member 10 and the second conductive member 20 provided in another embodiment of the present invention.

[0289] Optionally, the outer diameter of the buckle 29 decreases as it moves away from the base 28 .

[0290] The outer diameter of the buckle 29 decreases as it moves away from the base 28 , that is, the second conductive member 20 has a guiding slope at the front end of insertion, which is beneficial to the alignment of the snap connection.

[0291] Furthermore, the diameter of the conductive hole 111 is D1, the maximum outer diameter of the buckle 29 is D13, and 102%≤D13 / D1≤150%.

[0292] In order to ensure good contact between the buckle 29 and the first surface, the maximum outer diameter of the buckle 29, that is, the outer edge of the area where it contacts the first surface, should be large enough. Since the buckle 29 is interference fit when passing through the conductive hole 111, an excessively large outer diameter of the buckle 29 may cause the conductive hole 111 to be fractured. 102%≤D13 / D1≤150% can reduce the risk of the conductive hole 111 being fractured while ensuring stable contact between the buckle 29 and the first surface. D13 / D1 is preferably 105%, 108% or 110%.

[0293] Optionally, the diameter of the conductive hole 111 is D1, the minimum outer diameter of the buckle 29 is D14, and 60%≤D14 / D1≤97%.

[0294] The minimum outer diameter of the buckle 29, that is, the part of the buckle 29 that is first inserted into the conductive hole 111, assumes the function of guiding the insertion of the second conductive member 20. A sufficiently small D14 is conducive to guiding the insertion of the second conductive member 20, while an excessively small D14 does not enhance the guiding effect, but may cause the second conductive member 20 to collide with the edge of the conductive hole 111 when inserted. 60%≤D14 / D1≤97% is a value range with a good guiding effect, and D14 / D1 is preferably 85%, 90% or 92%.

[0295] Optionally, on any cross section passing through the axis of the buckle 29 , the angle between the tangent line of the outer contour of the buckle 29 and the first surface is A3, and 60%≤A3≤85%.

[0296] The angle between the tangent of the outer contour of the buckle 29 and the first surface determines the difficulty of inserting the buckle 29 into the conductive hole 111. The larger the A3, the easier it is to guide the alignment after the side wall of the buckle 29 contacts the edge of the conductive hole 111. At the same time, the insertion accuracy of the card connector is required to be higher; although a smaller A3 will reduce the alignment guiding force after the side wall of the buckle 29 contacts the edge of the conductive hole 111, it provides a larger eccentric error range for the insertion of the buckle 29. Under the same maximum outer diameter, the buckle 29 with a smaller A3 can guide the alignment under a larger eccentricity. 60%≤A3≤85% can maximize the eccentric error range under the premise that the abutment force of the edge of the conductive hole 111 is sufficient to complete the guidance. A3 is preferably 70% or 75%.

[0297] In some embodiments of the present application, the single cell further includes a second isolation sleeve 56 , which is sleeved on the through-post 25 , and the first conductive member 10 and the second conductive member 20 at least partially sandwich the second isolation sleeve 56 .

[0298] The second isolation sleeve 56 enhances the air tightness at the conductive hole 111. Due to the clamping of the first conductive member 10 and the second conductive member 20, the second isolation sleeve 56 can undergo adaptive slight deformation according to the surfaces of the two, further filling the surface defects of the parts that may damage the air tightness.

[0299] Please also read Fig.18 As shown, Fig.18 It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20 and the second isolation sleeve 56 provided in another embodiment of the present invention.

[0300] Furthermore, the first conductive member 10 includes a plate body 11 and a boss 12 . The conductive hole 111 is opened in the plate body 11 . The boss 12 is protruded from the inner wall of the conductive hole 111 . The boss 12 and the base 28 sandwich a second isolation sleeve 56 .

[0301] The second isolation sleeve 56 is sandwiched between the second conductive member 20 and the boss 12, which can better position the second isolation member and prevent the second isolation member from being pushed out of the conductive hole 111 during the insertion of the second conductive member 20, thereby affecting the assembly effect and sealing ability.

[0302] Specifically, the height of the boss 12 is H2, 1mm≤H2≤5mm.

[0303] The height of the boss 12 affects the bearing capacity of the boss 12. If the height of the boss 12 is too small, there is a risk of being crushed by the second conductive member 20. If the height of the boss 12 is too large, the space for placing the second isolation member is too small, affecting the sealing effect. 0.5mm<H2≤5mm is the choice to minimize the space occupied by the boss 12 while ensuring the strength of the boss 12.

[0304] Specifically, the height of the boss 12 is H2, the thickness of the first conductive member 10 is L11, and 40%≤H2 / L11≤60%.

[0305] The height of the boss 12 is also affected by the thickness of the first conductive part 10. In actual production, in addition to ensuring its own strength, the height of the boss 12 also needs to consider the thickness of the first conductive part 10. 20%≤H2 / L11≤60% can provide as much space as possible for the second isolation part while ensuring the strength of the boss 12 itself.

[0306] Specifically, the height of the boss 12 is H2, the thickness of the first conductive member 10 is L11, the natural length of the second isolation sleeve 56 is L12, and H2+L12≥L11.

[0307] The sum of the height of the boss 12 and the natural length of the second isolation sleeve 56 is greater than the thickness of the first conductive member 10, that is, when the second conductive member 20 is inserted into the conductive hole 111 and assembled in place, the second isolation sleeve 56 is squeezed, the length becomes shorter, and the thickness increases, so that the sealing effect is better.

[0308] Please also read Fig.19 As shown, Fig.19It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20 and the second isolation sleeve 52 provided in another embodiment of the present invention.

[0309] Optionally, the second isolation sleeve 56 includes a ring sleeve portion 561 and a gasket portion 562 , the ring sleeve portion 561 is at least partially inserted into the conductive hole 111 , and the gasket portion 562 is at least partially sandwiched between the base 28 and the first conductive member 10 .

[0310] The gasket portion 562 of the second isolation sleeve 56 is sandwiched between the second conductive member 20 and the first conductive member 10 , so that the position of the second isolation sleeve 56 is fixed by the edge of the conductive hole 111 , thereby preventing the second isolation sleeve 56 from sliding into the conductive hole 111 and causing assembly errors.

[0311] Specifically, the outer diameter of the gasket portion 562 is D10, the outer diameter of the base 28 is D12, and 70%≤D12 / D10≤120%.

[0312] The diameter of the gasket portion 562 should be as close as possible to the outer diameter of the base 28. If the size difference between the two is too large, redundant structures will be generated, which will increase the production cost. 70% ≤ D12 / D10 ≤ 120%. Under the premise of machining accuracy, D12 / D10 can be 98%, 100% or 102%.

[0313] Specifically, the thickness of the gasket portion 562 is L13, 0.5≤L13≤1.5 mm.

[0314] The thickness of the gasket portion 562 is an important parameter that affects the insulation and sealing performance of the second isolation sleeve 56. A gasket portion 562 that is too thin cannot be well sealed and is easily squeezed and damaged during clamping. A second isolation sleeve 56 that is too thick will take up extra space and affect the space utilization of the single battery.

[0315] Please also read Fig. 20 As shown, Fig. 20 yes Figure 2 A partial enlarged view of the E area.

[0316] In some embodiments of the present application, the first conductive member 10 is further formed with a pressure relief groove 114 , and the pressure relief groove 114 is recessed on the surface of the first conductive member 10 to avoid the conductive hole 111 .

[0317] The provision of the pressure relief groove 114 reduces the structural strength of the first conductive member 10 in the corresponding area, making it a structural weakness of the single cell housing. When an unexpected situation occurs inside the single cell, such as thermal runaway, causing the internal pressure to rise, the first conductive member 10 in the pressure relief groove 114 area is destroyed, and the internal pressure of the single cell is released, thereby avoiding the occurrence of explosion due to excessive accumulation of internal pressure.

[0318] Furthermore, the distance between the edge of the pressure relief groove 114 and the edge of the conductive hole 111 is L15, 2mm<L15<35mm.

[0319] The pressure relief groove 114 is arranged to avoid the conductive hole 111. The distance between the edge of the pressure relief groove 114 and the edge of the conductive hole 111 will have an additional impact on the structural strength of the first conductive member 10. When the pressure relief groove 114 and the conductive hole 111 are too close, there is a risk of cracking of the pressure relief groove 114 when the second conductive member 20 is assembled. 2mm<L15<35mm can ensure the stability of the assembly of the second conductive member 20 under the premise of the structure being as tight as possible. L15 is preferably 2mm, 3mm or 5mm.

[0320] Optionally, the maximum width of the pressure relief groove 114 is L16, 0.05 mm ≤ L16 ≤ 5 mm.

[0321] The width of the pressure relief groove 114 affects the distribution of the structural weak surface formed by it. If the pressure relief groove 114 is too narrow, the pressure relief effect will be weak. If the pressure relief groove 114 is too wide, it will have a greater impact on the structural strength of the first conductive member 10, so that it is also at risk of rupture under normal use conditions. 0.05mm≤L16≤5mm can meet the pressure relief function of the pressure relief groove 114 while ensuring the structural strength of the first conductive member 10. L16 is preferably 0.1mm or 0.2mm.

[0322] Optionally, the first conductive member 10 includes a first surface and a second surface that are arranged opposite to each other, the first surface is used to face the battery cell assembly 30, and the pressure relief groove 114 is opened on the second surface.

[0323] The pressure relief groove 114 is opened on the second surface. When the internal pressure of the single cell rises, the first surface of the first conductive member 10 is pressurized, the first conductive member 10 bulges outward, and the pressure relief groove 114 tends to open. There is also stress concentration at the bottom of the pressure relief groove 114, which is conducive to the destruction of the first conductive member 10 when the internal pressure of the single cell rises.

[0324] Specifically, the distance between the bottom of the pressure relief groove 114 and the first surface is L17, 0.02 mm≤L17≤1.5 mm.

[0325] If the distance between the bottom of the pressure relief groove 114 and the first surface is too large, the pressure relief effect will be weak. If the distance between the bottom of the pressure relief groove 114 and the first surface is too small, the structural strength of the first conductive member 10 will be greatly affected, and there is a risk of rupture under normal use conditions. 0.02mm≤L17≤1.5mm can meet the pressure relief function of the pressure relief groove 114 while ensuring the structural strength of the first conductive member 10. L17 is preferably 0.1mm or 0.15mm.

[0326] It should be noted that the bottom here does not refer to a specific plane, but should be understood as the position in the pressure relief groove 114 closest to the first surface, and the shape of this embodiment cannot be limited to this.

[0327] Optionally, the included angle of the pressure relief groove 114 relative to the two groove walls is A4, 20°≤A4≤90°.

[0328] The angle A4 is related to the stress concentration at the bottom of the pressure relief groove 114. When the angle A4 is too small, the stress concentration at the bottom of the pressure relief groove 114 will be more obvious, and the first conductive member 10 will also crack when the single cell is working normally and generating heat. When the angle A4 is too large, the width of the widest part of the pressure relief groove 114 will be too large, which will also affect the strength of the first conductive member 10. It is found through experiments that 20°≤A4≤90° is a better angle range, and A4 is further preferably 50° or 60°.

[0329] Please also read Fig.21 As shown, Fig.21 It is a schematic diagram of the coordination between the pressure relief groove 114 and the second conductive member 20 provided in another embodiment of the present invention.

[0330] Optionally, the cross section of the pressure relief groove 114 perpendicular to the extension direction thereof is a trapezoid, and the lower base of the trapezoid is located on the surface of the first conductive member 10 .

[0331] The presence of a plane at the bottom of the pressure relief groove 114 can alleviate stress concentration to a certain extent, enhance the structural strength of the first conductive component 10 while keeping the depth of the pressure relief groove 114 and the thickness of the first conductive component 10 unchanged, and avoid accidental damage to the first conductive component 10 during normal use.

[0332] Specifically, the length of the upper base of the trapezoid is L18, 0.02mm≤L18≤3mm.

[0333] If the length of the upper bottom is too small, the effect of relieving stress concentration will not be obvious enough. If the length of the upper bottom is too large, the pressure relief groove 114 will be too wide, which will also affect the structural strength of the first conductive member 10. 0.02mm≤L18≤3mm is the value range that is not prone to stress concentration while maintaining a narrow pressure relief groove 114. L18 is preferably 1mm.

[0334] Please also read Fig. 22 As shown, Fig. 22 It is a schematic diagram of the coordination between the pressure relief groove 114 and the second conductive member 20 provided in another embodiment of the present invention.

[0335] Optionally, the bottom of the pressure relief groove 114 has rounded corners.

[0336] The rounded corners at the bottom of the pressure relief groove 114 can alleviate stress concentration to a certain extent, enhance the structural strength of the first conductive component 10 while keeping the depth of the pressure relief groove 114 and the thickness of the first conductive component 10 unchanged, and avoid accidental damage to the first conductive component 10 during normal use.

[0337] Specifically, the radius of the fillet is R1, the maximum width of the pressure relief groove 114 is L16, and 20%≤R1 / L16≤100%.

[0338] If the radius of the fillet is too small, the effect of relieving stress concentration will not be obvious enough. If the radius of the fillet is too large, the pressure relief groove 114 will be too wide, which will also affect the structural strength of the first conductive member 10. 20%≤R1 / L16≤100% is the value range that is not prone to stress concentration while maintaining a narrow pressure relief groove 114. R1 / L16 is preferably 50%.

[0339] Please also read Fig.23 As shown, Fig.23 It is a schematic diagram of the coordination of the first conductive member 10, the second conductive member 20 and the fourth isolation layer 54 provided in an embodiment of the present invention.

[0340] In some embodiments of the present application, the single battery further includes a fourth isolation layer 54 , and the fourth isolation layer 54 covers a surface of the first conductive member 10 facing the battery cell assembly 30 .

[0341] The fourth isolation layer 54 covers the surface of the first conductive member 10 facing the battery cell assembly 30 , isolating the first conductive member 10 at least partially from the electrolyte, thereby alleviating the corrosion rate of the first conductive member 10 and extending the service life of the single battery.

[0342] Exemplarily, the fourth isolation layer 54 is a nickel plating layer or an iron alloy plating layer.

[0343] The nickel plating layer or iron alloy plating layer has electrical conductivity. When the fourth isolation layer 54 is sandwiched between the first conductive member 10 and the second conductive member 20, the fourth isolation layer 54 can share part of the current, isolating the first conductive member 10 and the second conductive member 20 immersed in the electrolyte area without causing a significant impact on the current carrying capacity of the single cell.

[0344] Exemplarily, the fourth isolation layer 54 is a PP film or PPS.

[0345] PP film and PPS film are relatively mature protective materials in the lithium battery field, with low cost and high processing efficiency.

[0346] Specifically, the area of ​​the first conductive member 10 close to the battery cell assembly 30 is S1, the projection area of ​​the fourth isolation layer 54 on the surface of the first conductive member 10 is S8, and 5%≤S8 / S1≤97%.

[0347] The area ratio of the fourth isolation layer 54 is related to its isolation capability, and 5%≤S8 / S1≤97% is an optimal value range in experiments.

[0348] Specifically, the thickness of the fourth isolation layer 54 is L19, 0.05 mm ≤ L19 ≤ 2 mm.

[0349] The isolation effect of the fourth isolation layer 54 is positively correlated with its thickness. A fourth isolation layer 54 that is too thin is at risk of being penetrated, and a fourth isolation layer 54 that is too thick will cause additional space occupation and increase in production costs. 0.05mm≤L19≤2mm is a value range that minimizes space occupation while ensuring the isolation effect.

[0350] Specifically, the thickness of the fourth isolation layer 54 is evenly distributed on the entire surface of the first conductive member 10 .

[0351] The evenly distributed fourth isolation layer 54 has a uniform isolation effect, a simple processing technology and high production efficiency.

[0352] Please also read Fig.24 As shown, Fig.24 It is a schematic diagram of the coordination of the first conductive member 10 , the second conductive member 20 and the fourth isolation layer 54 provided in another embodiment of the present invention.

[0353] Optionally, the thickness of the fourth isolation layer 54 increases as it approaches the conductive hole 111 .

[0354] There are multiple component abutment surfaces near the conductive hole 111 , and a larger thickness of the fourth isolation layer 54 applied near the conductive hole 111 can effectively enhance the isolation effect in the corresponding area.

[0355] In some embodiments of the present application, the thickness of the first conductive member 10 is L11, 0.5 mm ≤ L11 ≤ 2 mm.

[0356] The first conductive part 10 has the functions of conduction and physical protection. A first conductive part 10 that is too thin will have poor current carrying capacity and structural strength, while a first conductive part 10 that is too thick will increase production costs and cause additional weight and volume. 0.5mm≤L11≤2mm is a value range that can maintain good structural strength and current carrying capacity while minimizing space occupancy, and L11 is preferably 1mm.

[0357] It should be noted that the first conductive member 10 may be composed of multiple plates 11 , each of which is located in a different plane. In this case, L11 should be defined as the thickness of the plate 11 rather than the distance between the surfaces of the two farthest plates 11 .

[0358] Please also read Fig.25 As shown, Fig.25It is a schematic diagram of the connection relationship between the first conductive member 10 and the housing 70 provided in an embodiment of the present invention.

[0359] In some embodiments of the present application, the single battery further includes a shell 70 , one side of the shell 70 is open, the first conductive member 10 blocks the opening of the shell 70 and together with the shell 70 forms an accommodating space, and the battery cell assembly 30 is disposed in the accommodating space.

[0360] The first conductive member 10 blocks the opening and encloses the shell 70 to form an accommodating space, and the battery cell assembly 30 is arranged in the accommodating space, so that the connection between the first conductive member 10 and the second conductive member 20 can be completed first. When the first conductive member 10 is buckled into the shell 70, the second conductive member 20 abuts against the battery cell assembly 30. Alternatively, the first conductive member 10, the shell 70 and the battery cell assembly 30 are assembled first, and then the second conductive member 20 is inserted into the conductive hole 111 and abuts against the battery cell assembly 30, and the assembly process is more flexible.

[0361] Furthermore, the single battery cell further includes a second weld 42 , and the first conductive member 10 and the shell 70 are connected via the second weld 42 .

[0362] The first conductive member 10 and the shell 70 are connected by the second weld 42, which ensures the connection strength and air tightness of the single cell shell. Moreover, since the second weld 42 undertakes a considerable part of the connection function, it also reduces the requirements for the welding strength between the second conductive member 20 and the battery cell assembly 30, making it less likely for the second conductive member 20 and the battery cell assembly 30 to be short-circuited.

[0363] Specifically, the height of the second weld 42 protruding from the surface of the shell 70 is H3, 0mm≤H3≤3mm.

[0364] The portion of the second weld 42 protruding from the surface of the shell 70 will increase the probability of scratches on adjacent single cells in the battery pack. Therefore, 0mm≤H3≤3mm is configured to protect the single cells and extend the service life of the single cells. If conditions permit, a grinder can also be used to make H3 as close to 0mm as possible.

[0365] Specifically, the width of the second weld 42 is L20, 2 mm ≤ L20 ≤ 6 mm.

[0366] Because the mechanical properties of the weld are usually greater than those of the parent material, a sufficiently large width of the second weld 42 can ensure the connection strength between the shell 70 and the first conductive member 10. However, due to the limitation of the strength of the shell 70 and the first conductive member 10 themselves, an excessively large second weld 42 cannot improve the overall strength of the single cell housing. 2mm≤L20≤6mm can minimize energy waste while ensuring the connection strength between the first conductive member 10 and the shell 70.

[0367] Optionally, the first conductive member 10 includes a first plate 13, a second plate 14 and a third plate 15, the conductive hole 111 is opened in the first plate 13, the third plate 15 is wrapped around the first plate 13, the shell 70 is connected to the third plate 15, the opposite ends of the second plate 14 are respectively connected to the first plate 13 and the third plate 15, and the first plate 13 and the second plate 14 are embedded in the opening of the shell 70.

[0368] The first plate 13 and the second plate 14 are embedded in the opening of the shell 70, and the first conductive part 10 and the shell 70 can be positioned without a mold before the third plate 15 and the shell 70 are welded, which serves as an anti-foolproof structure and avoids the risk of the assembler installing the first conductive part 10 upside down.

[0369] Furthermore, the first plate 13 and the second plate 14 are connected by an arc.

[0370] When the inner edge of the opening of the shell 70 abuts against the arc, there is a tendency to spontaneously guide the first plate 13 and the second plate 14 into the opening, which can guide assembly in addition to positioning, thereby reducing the requirements for alignment accuracy during the assembly process.

[0371] Specifically, the radius of the arc is R2, 0.1 mm ≤ R2 ≤ 2 mm.

[0372] Too small an arc radius results in a smaller alignment guiding area and weaker guiding effect, while too large an arc radius reduces the connection strength between the first plate 13 and the second plate 14. 0.1 mm ≤ R2 ≤ 2 mm can obtain as obvious a guiding effect as possible while ensuring the structural strength of the first conductive member 10, and R2 is preferably 0.5 mm or 1 mm.

[0373] Specifically, the radius of the arc is R2, the thickness of the first plate 13 is L21, and 20%≤R2 / L21≤100%.

[0374] The radius of the arc is also affected by the thickness of the first plate 13. A too small arc radius results in a smaller alignment guide area and a weaker guide effect, while a too large arc radius reduces the connection strength between the first plate 13 and the second plate 14. 20% ≤ R2 / L21 ≤ 100% can obtain as obvious a guide effect as possible while ensuring the structural strength of the first conductive member 10, and R2 / L21 is preferably 50%.

[0375] Optionally, an assembly gap 80 exists between the second plate 14 and the housing 70 .

[0376] The existence of the assembly gap 80 facilitates the embedding of the first plate 13 and the second plate 14 and reduces the alignment accuracy requirement during the assembly process.

[0377] Specifically, the width of the assembly gap 80 is L22, and 0.1 mm≤L22≤0.5 mm.

[0378] An assembly gap 80 that is too small is difficult to significantly optimize the assembly process, and an assembly gap 80 that is too large will affect the airtightness between the first conductive member 10 and the housing 70. Therefore, the configuration of 0.1mm≤L22≤0.5mm can reduce the alignment accuracy requirement as much as possible while ensuring airtightness, and L22 is preferably 0.4mm or 0.5mm. It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0379] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or may be indirectly connected to the other element through an intermediate element.

[0380] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0381] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the design concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A single cell battery, characterized in that: include: A first conductive member having a conductive hole formed therein, wherein the conductive hole penetrates the first conductive member in a thickness direction of the first conductive member; A second conductive member, through which the conductive hole is formed, and the second conductive member is fixed to and electrically connected to the first conductive member; The battery cell assembly is connected to the second conductive member by welding.

2. The single cell according to claim 1, characterized in that: A welding hole is also formed on the second conductive member, and the opening direction of the welding hole is toward a side of the second conductive member away from the battery core assembly.

3. The single cell according to claim 2, characterized in that: The diameter of the conductive hole is D1, the diameter of the welding hole is D2, and 30%≤D2 / D1≤90%.

4. The single cell according to claim 2, characterized in that: The depth of the welding hole is L1, the projection length of the second conductive member in the thickness direction of the first conductive member is L2, and 50%≤L1 / L2≤90%.

5. The single cell according to claim 2, characterized in that: The minimum distance between the hole wall of the welding hole and the outer wall of the second conductive member is L3, and L3≥0.05 mm.

6. The single cell according to claim 2, characterized in that: The distance between the bottom of the welding hole and the surface of the second conductive member on one side close to the battery core assembly is L4, and 0.05mm≤L4≤2mm.

7. The single cell according to claim 1, characterized in that: The battery cell assembly includes a battery cell and a busbar, and the busbar is electrically connected to the battery cell and the second conductive member respectively.

8. The single cell according to claim 7, characterized in that: The area of ​​the first conductive member close to the battery cell assembly is S1, the projected area of ​​the contact surface between the second conductive member and the busbar on the first conductive member is S2, and 20%≤S2 / S1≤90%.

9. The single cell according to claim 7, characterized in that: The second conductive member is connected to the busbar via a first weld, a projection area of ​​the first weld on the surface of the busbar is S3, a surface area of ​​the busbar close to the first conductive member structure is S4, and S3 / S4≥10%.

10. The single cell according to claim 7, characterized in that: The second conductive member is welded to a side of the busbar close to the first conductive member, and a side of the busbar away from the second conductive member is electrically connected to the battery cell.

11. The single cell according to claim 7, characterized in that: The second conductive member and the busbar are made of the same material.

12. The single cell according to claim 1, characterized in that: The battery cell assembly comprises a winding core and a pole tab which are electrically connected, and the pole tab is welded to the second conductive member.

13. The single cell according to claim 12, characterized in that: The second conductive member and the tab are made of the same material.

14. The single cell according to claim 1, characterized in that: There are a plurality of the conductive holes, and the second conductive members are arranged corresponding to the conductive holes one by one.

15. The single cell according to claim 14, characterized in that: A plurality of the electrical conductive holes are arranged in a circular array on the first conductive member.

16. The single cell according to claim 1, characterized in that: The material of the second conductive member includes copper.

17. The single cell according to claim 16, characterized in that: The single battery further includes a first isolation layer, the first isolation layer wraps the second conductive member, and a side of the second conductive member close to the battery cell assembly is at least partially exposed.

18. The single cell according to claim 17, characterized in that: The material of the first isolation layer includes at least one of steel and nickel.

19. The single cell according to claim 17, characterized in that: The area of ​​the exposed portion of the second conductive member on one side close to the battery cell assembly is S5, the area of ​​the first conductive member on one side close to the battery cell assembly is S1, and 40%≤S5 / S1≤100%.

20. The single cell according to claim 1, characterized in that: The second conductive member and the first conductive member are fixed by riveting.

21. The single cell according to claim 20, characterized in that: The first conductive member includes a first surface and a second surface opposite to each other, and the second conductive member includes: A rivet post, through which the electrical conduction hole is formed; A rivet seat connected to one end of the rivet column, the rivet seat abutting against the first surface; A rivet buckle is connected to an end of the rivet column away from the rivet seat, and the rivet buckle is riveted to the second surface.

22. The single cell according to claim 21, characterized in that: An outer edge of one end of the rivet button away from the rivet seat is provided with an outer chamfer, and on any cross section passing through the axis of the rivet button, an angle A1 is included between the outer chamfer and the second surface, and 10°≤A1≤85°.

23. The single cell according to claim 22, characterized in that: The distance between the outer edge of the outer chamfer and the second surface is L5, the thickness of the rivet is L6, and 0≤L5 / L6≤70%.

24. The single cell according to claim 21, characterized in that: The thickness of the rivet button is L6, the projection length of the second conductive member in the thickness direction of the rivet button is L7, and 10%≤L6 / L7≤40%.

25. The single cell according to claim 21, characterized in that: The diameter of the conductive hole is D1, the outer diameter of the rivet button is D3, and 120%≤D3 / D1≤200%.

26. The single cell according to claim 21, characterized in that: The diameter of the rivet seat is D4, 2mm≤D4≤20mm.

27. The single cell according to claim 21, characterized in that: The diameter of the conductive hole is D1, the diameter of the rivet seat is D4, and 130%≤D4 / D1≤200%.

28. The single cell according to claim 21, characterized in that: The thickness of the rivet seat is L8, 0.05mm≤L8≤2mm.

29. The single cell according to claim 21, characterized in that: The single cell further includes a first isolation sleeve, the rivet column passes through the first isolation sleeve, and the first isolation sleeve is sandwiched between the rivet seat and the first surface.

30. The single cell according to claim 29, characterized in that: The diameter of the rivet seat is D4, the outer diameter of the first isolation sleeve is D5, and 70%≤D4 / D5≤120%.

31. The single cell according to claim 29, characterized in that: The thickness of the first isolation sleeve is L9, 0.5≤L9≤1.5mm.

32. The single cell according to any one of claims 20 to 31, characterized in that: A rivet hole is also formed on the second conductive member, and the opening direction of the rivet hole is toward a side of the second conductive member away from the battery core assembly.

33. The single cell according to claim 32, characterized in that: The edge of the riveting hole is provided with an inner chamfer, and on any cross section passing through the axis of the riveting hole, the angle between the inner chamfer plane and the second surface is A2, 30°≤A2≤85°.

34. The single cell according to claim 32, characterized in that: The diameter of the riveting hole is D6, the minimum outer diameter of the second conductive member is D7, and 30%≤D6 / D7≤80%.

35. The single cell according to claim 1, characterized in that: The single cell battery also includes a fastener, the second conductive member includes a through column and a retaining edge, the through column is penetrated through the conductive hole, the retaining edge abuts against the first conductive member, and the fastener penetrates through at least one of the first conductive member and the second conductive member to achieve the connection between the first conductive member and the second conductive member.

36. The single cell according to claim 35, characterized in that: The retaining edge is provided with a first hole, and the fastener passes through the first hole and is connected with the first conductive member.

37. The single cell according to claim 36, characterized in that: A second isolation layer is provided between the first conductive member and the second conductive member.

38. The single cell according to claim 36, characterized in that: A third isolation layer is provided on the surface of the fastener that contacts the first conductive member and the second conductive member.

39. The single cell according to any one of claims 37 to 38, characterized in that: The second isolation layer or the third isolation layer is a nickel plating layer.

40. The single cell according to any one of claims 37 to 38, characterized in that: The second isolation layer or the third isolation layer is at least one of a PP film and a PPS film.

41. The single cell according to claim 36, characterized in that: A distance between a surface of the through-column close to the battery cell assembly and a surface of the first conductive member close to the battery cell assembly is H1, and 0.8≤H1≤2mm.

42. The single cell according to claim 36, characterized in that: The projection area of ​​the outer edge of the rib on the first conductive member is S6, the contact area between the rib and the first conductive member is S7, and 5%≤S7 / S6≤35%.

43. The single cell according to claim 36, characterized in that: There are a plurality of first holes on each of the ribs.

44. The single cell according to claim 43, characterized in that: A plurality of the first holes are distributed in a circumferential array on the rib.

45. The single cell according to claim 36, characterized in that: The retaining edge abuts against a side of the first conductive member away from the battery core assembly.

46. ​​The single cell according to claim 36, characterized in that: The diameter of the first hole is D8, 2.5 mm≤D8≤16 mm.

47. The single cell according to claim 36, characterized in that: The first conductive member is provided with a second hole, and the fastener passes through the first hole and is inserted into the second hole.

48. The single cell according to claim 47, characterized in that: The fastener is a screw, and the fastener is threadedly matched with the second hole.

49. The single cell according to claim 35, characterized in that: A third hole is formed on the first conductive member, and the fastener passes through the third hole and is connected to the second conductive member.

50. The single cell according to any one of claims 36 to 49, characterized in that: The fastener includes a first part and a second part connected to each other, the first part is inserted into the first hole or the third hole, the second part abuts against a side of the second conductive member away from the first conductive member, or the second part abuts against a side of the first conductive member away from the second conductive member.

51. The single cell according to claim 50, characterized in that: The diameter of the first portion is D9, 2.5 mm ≤ D9 ≤ 16 mm.

52. The single cell according to claim 50, characterized in that: The thickness of the second portion is L10, 0.5 mm ≤ L10 ≤ 2 mm.

53. The single cell according to any one of claims 35 to 52, characterized in that: The single cell further includes a second isolation sleeve, which is sleeved on the through-column, and the first conductive member and the second conductive member at least partially sandwich the second isolation sleeve.

54. The single cell according to claim 53, characterized in that: The first conductive member comprises a plate body and a boss, the conductive hole is opened in the plate body, the boss is protruded from the inner wall of the conductive hole, and the second isolation sleeve is sandwiched between the boss and the retaining edge.

55. The single cell according to claim 54, characterized in that: The height of the boss is H2, 0.5mm<H2≤5mm.

56. The single cell according to claim 54, characterized in that: The height of the boss is H2, the thickness of the first conductive member is L11, and 20%≤H2 / L11≤50%.

57. The single cell according to claim 54, characterized in that: The height of the boss is H2, the thickness of the first conductive member is L11, the natural length of the second isolation sleeve is L12, and H2+L12>L11.

58. The single cell according to claim 53, characterized in that: The second isolation sleeve includes a ring sleeve portion and a gasket portion, wherein the ring sleeve portion is at least partially inserted into the conductive hole, and the gasket portion is at least partially sandwiched by the retaining edge and the first conductive member.

59. The single cell according to claim 58, characterized in that: The outer diameter of the gasket portion is D10, the outer diameter of the retaining edge is D11, and 70%≤D11 / D10≤120%.

60. The single cell according to claim 58, characterized in that: The thickness of the gasket portion is L13, 0.5≤L13≤1.5mm.

61. The single cell according to claim 1, characterized in that: The second conductive member is inserted into the conductive hole and is snap-connected with the first conductive member.

62. The single cell according to claim 61, characterized in that: The first conductive member includes a first surface and a second surface that are oppositely disposed, and the second conductive member includes: A connecting rod, through which the electrical conduction hole is penetrated; A base, connected to one end of the connecting rod, the base abutting against the second surface; A buckle is connected to an end of the connecting rod away from the base, and the buckle is clamped on the first surface.

63. The single cell according to claim 62, characterized in that: The outer diameter of the base is D12, 2mm≤D12≤20mm.

64. The single cell according to claim 62, characterized in that: The diameter of the conductive hole is D1, the outer diameter of the base is D12, and 130%≤D12 / D1≤200%.

65. The single cell according to claim 62, characterized in that: The thickness of the base is L14, 0.2mm≤L14≤2mm.

66. The single cell according to claim 62, characterized in that: The outer diameter of the buckle decreases as it moves away from the base.

67. The single cell according to claim 66, characterized in that: The diameter of the conductive hole is D1, the maximum outer diameter of the buckle is D13, and 102%≤D13 / D1≤150%.

68. The single cell according to claim 66, characterized in that: The diameter of the conductive hole is D1, the minimum outer diameter of the buckle is D14, and 60%≤D14 / D1≤97%.

69. The single cell according to claim 66, characterized in that: On any cross section passing through the buckle axis, the angle between the tangent line of the buckle outer contour and the first surface is A3, and 60%≤A3≤85%.

70. The single cell according to any one of claims 62 to 69, characterized in that: The single cell further includes a second isolation sleeve, which is sleeved on the through-column, and the first conductive member and the second conductive member at least partially sandwich the second isolation sleeve.

71. The single cell according to claim 70, characterized in that: The first conductive member includes a plate body and a boss, the conductive hole is opened in the plate body, the boss is protruded from the inner wall of the conductive hole, and the second isolation sleeve is sandwiched between the boss and the base.

72. The single cell according to claim 71, characterized in that: The height of the boss is H2, 1mm≤H2≤5mm.

73. The single cell according to claim 71, characterized in that: The height of the boss is H2, the thickness of the first conductive member is L11, and 40%≤H2 / L11≤60%.

74. The single cell according to claim 71, characterized in that: The height of the boss is H2, the thickness of the first conductive member is L11, the natural length of the second isolation sleeve is L12, and H2+L12≥L11.

75. The single cell according to claim 70, characterized in that: The second isolation sleeve includes a ring sleeve portion and a gasket portion, wherein the ring sleeve portion is at least partially inserted into the conductive hole, and the gasket portion is at least partially sandwiched between the base and the first conductive member.

76. The single cell according to claim 75, characterized in that: The outer diameter of the gasket portion is D10, the outer diameter of the base is D12, and 70%≤D12 / D10≤120%.

77. The single cell according to claim 75, characterized in that: The thickness of the gasket portion is L13, 0.5≤L13≤1.5mm.

78. The single cell according to any one of claims 1 to 77, characterized in that: The first conductive member is further formed with a pressure relief groove, and the pressure relief groove is recessed on the surface of the first conductive member to avoid the electrical conduction hole.

79. The single cell according to claim 78, characterized in that: The distance between the edge of the pressure relief groove and the edge of the conductive hole is L15, 2mm<L15<35mm.

80. The single cell according to claim 78, characterized in that: The maximum width of the pressure relief groove is L16, 0.05mm≤L16≤5mm.

81. The single cell according to claim 78, characterized in that: The first conductive member includes a first surface and a second surface that are arranged opposite to each other, the first surface is used to face the battery core assembly, and the pressure relief groove is opened on the second surface.

82. The single cell according to claim 81, characterized in that: The distance between the bottom of the pressure relief groove and the first surface is L17, 0.02mm≤L17≤1.5mm.

83. The single cell according to claim 78, characterized in that: The included angle of the pressure relief groove relative to the two groove walls is A4, 20°≤A4≤90°.

84. The single cell according to claim 78, characterized in that: The cross section of the pressure relief groove perpendicular to the extension direction thereof is a trapezoid, and the lower base of the trapezoid is located on the surface of the first conductive member.

85. The single cell according to claim 84, characterized in that: The upper base length of the trapezoid is L18, 0.02mm≤L18≤3mm.

86. The single cell according to claim 78, characterized in that: The bottom of the pressure relief groove has a rounded corner.

87. The single cell according to claim 86, characterized in that: The radius of the fillet is R1, the maximum width of the pressure relief groove is L16, and 20%≤R1 / L16≤100%.

88. The single cell according to any one of claims 1 to 77, characterized in that: The single battery further includes a fourth isolation layer, and the fourth isolation layer covers a surface of the first conductive member on one side facing the battery core assembly.

89. The single cell according to claim 88, characterized in that: The fourth isolation layer is a nickel plating layer or an iron alloy plating layer.

90. The single cell according to claim 88, characterized in that: The fourth isolation layer is one of PP film and PPS.

91. The single cell according to claim 88, characterized in that: The area of ​​the first conductive member close to the battery core assembly is S1, the projection area of ​​the fourth isolation layer on the surface of the first conductive member is S8, and 5%≤S8 / S1≤97%.

92. The single cell according to claim 88, characterized in that: The thickness of the fourth isolation layer is L19, 0.05mm≤L19≤2mm.

93. The single cell according to claim 88, characterized in that: The thickness of the fourth isolation layer is evenly distributed on the entire surface of the first conductive member.

94. The single cell according to claim 88, characterized in that: The thickness of the fourth isolation layer increases as it approaches the conductive hole.

95. The single cell according to any one of claims 1 to 77, characterized in that: The thickness of the first conductive member is L11, 0.5 mm ≤ L11 ≤ 2 mm.

96. The single cell according to any one of claims 1 to 77, characterized in that: The single battery further comprises a shell, one side of which is open, the first conductive member blocks the opening of the shell and is combined with the shell to form an accommodating space, and the battery cell assembly is arranged in the accommodating space.

97. The single cell according to claim 96, characterized in that: The single battery further includes a second weld, and the first conductive member and the shell are connected via the second weld.

98. The single cell according to claim 97, characterized in that: The height of the second weld protruding from the shell surface is H3, 0mm≤H3≤3mm.

99. The single cell according to claim 97, characterized in that: The width of the second weld is L20, 2mm≤L20≤6mm.

100. The single cell according to claim 96, characterized in that: The first conductive member includes a first plate, a second plate and a third plate, the conductive hole is opened in the first plate, the third plate is wound around the first plate, the shell is connected to the third plate, the opposite ends of the second plate are respectively connected to the first plate and the third plate, and the first plate and the second plate are embedded in the opening of the shell.

101. The single cell according to claim 100, characterized in that: The first plate and the second plate are connected by an arc.

102. The single cell according to claim 101, characterized in that: The radius of the arc is R2, 0.1mm≤R2≤2mm.

103. The single cell according to claim 101, characterized in that: The radius of the arc is R2, the thickness of the first plate is L21, and 20%≤R2 / L21≤100%.

104. The single cell according to claim 100, characterized in that: An assembly gap exists between the second plate and the housing.

105. The single cell according to claim 104, characterized in that: The width of the assembly gap is L22, 0.1mm≤L22≤0.5mm.

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