Top cover assembly, battery cell, battery and electric device

Abstract

The present application relates to the technical field of batteries. Provided are a top cover assembly, a battery cell, a battery and an electric device. The top cover assembly comprises: a cover plate having a first surface, a second surface and a first through hole, wherein the first surface and the second surface face away from each other, and the first through hole runs through the first surface and the second surface; a terminal post comprising at least one first connection portion and at least two second connection portions, wherein each first connection portion is connected to two adjacent second connection portions, the at least two second connection portions are spaced apart in the direction of width of the cover plate, the first connection portion is arranged on the side of the cover plate having the first surface and is configured to be connected to an electrical connector, and at least part of each second connection portion passes through the first through hole and is configured to be connected to a tab; and a first insulating member comprising a third insulating portion, at least part of the third insulating portion being arranged between the first connection portion and the cover plate.

Description

Top cover assembly, battery cells, battery and electrical devices

[0001] This application claims priority to patent application No. 202510096537.0, filed with the China National Intellectual Property Administration on January 21, 2025, entitled "A Top Cover Assembly, Battery and Electrical Device", and also claims priority to patent application No. 202510653361.4, filed with the China National Intellectual Property Administration on May 20, 2025, entitled "A Top Cover Assembly, Battery Cell, Battery and Electrical Device". Technical Field

[0002] This application relates to the field of battery technology, and in particular to a top cover assembly, a battery cell, a battery, and an electrical device. Background Technology

[0003] Lithium-ion batteries have advantages such as high energy density, long cycle life, high rate performance, good safety, and environmental friendliness, making them an important energy product for modern electronic products and electric vehicles. The battery cell is a crucial component of the battery.

[0004] There are two technical solutions for battery cells: those with adapter plates and those without. In the adapter plate solution, the tabs of the cell are led out to the terminals via the adapter plate, making the terminals the electrode terminals of the battery cell. However, the presence of the adapter plate increases the number of parts, thus increasing battery cost; furthermore, it adds a welding process between the tabs and the adapter plate, further increasing battery cost.

[0005] In adapter-less designs, the terminals and tabs are directly connected. However, due to limited space on the cover plate, the position of the terminals is restricted, necessitating the use of extended tabs to achieve direct connection. Extending the tabs significantly increases the risk of the tabs being inserted backwards into the cell and of tearing. Furthermore, the design dimensions of the terminals are also limited, resulting in weaker current-carrying capacity, which is detrimental to improving the battery's charge / discharge performance and safety.

[0006] Application content

[0007] Therefore, it is necessary to provide a top cover assembly, battery cell, battery, and power device that can eliminate the need for adapters and avoid lengthening the electrode tabs, in order to address the above problems.

[0008] On one hand, this application provides a top cover assembly, including: a cover plate having a first surface, a second surface, and a first through hole, the first surface and the second surface being opposite to each other, and the first through hole penetrating the first surface and the second surface; an electrode post including at least one first connecting portion and at least two second connecting portions, the first connecting portion being located on the side of the cover plate having the first surface, each of the second connecting portions being connected to the first connecting portion and arranged along the width direction of the cover plate; each second connecting portion being at least partially inserted into the first through hole and used for connecting to an electrode tab respectively; and a third insulating portion including a first sub-insulating portion disposed between the first connecting portion and the cover plate.

[0009] In some embodiments, on a dummy plane perpendicular to the thickness direction of the cover plate, the orthographic projection of the first connecting portion does not coincide with the orthographic projection of the first through hole, and the orthographic projection of the second connecting portion covers the orthographic projection of the first through hole.

[0010] In some embodiments, each second connection portion includes a first region and a second region arranged around the first region. The second region is connected to the first connection portion. The first region protrudes relative to the second region in a direction from the first surface to the second surface and forms a connection sub-port passing through the first through hole.

[0011] In some embodiments, the end of the connecting sub-part away from the second region is a welding end, the welding end has a welding surface, and the welding end protrudes from the second surface of the cover plate.

[0012] In some embodiments, the top cover assembly further includes a second insulating member disposed on a second surface of the cover plate, with a welded end penetrating through the second insulating member, and a welded surface protruding from the side surface of the second insulating member away from the cover plate, or the welded surface being flush with the side surface of the second insulating member away from the cover plate.

[0013] In some embodiments, the welding end protrudes from the second surface along the thickness direction of the cover plate by a distance of 0 to 5 mm.

[0014] In some embodiments, the distance between the weld mark on the welding surface and the edge of the welding surface is greater than or equal to 1 mm.

[0015] In some embodiments, the third insulating portion further includes a third sub-insulating portion, at least a portion of which covers the second region.

[0016] In some embodiments, the first sub-insulating portion and the third sub-insulating portion are integrally formed.

[0017] In some embodiments, the end face of the connecting sub-part connected to the second region has a first groove, and the third sub-insulating part also covers the inner wall of the first groove.

[0018] In some embodiments, the third sub-insulating portion is recessed into the first groove to form a pit.

[0019] In some embodiments, the top cover assembly further includes a first fixing portion connected to a first surface of the cover plate and pressing against the side of the third sub-insulating portion away from the cover plate.

[0020] In some embodiments, the first fixing portion extends along the peripheral edge of the second connecting portion.

[0021] In some embodiments, the first fixing part includes a first arc segment, a straight edge segment, and a second arc segment connected in sequence, and both the first arc segment and the second arc segment are located on the side of the straight edge segment facing the first connecting part; a clearance space is formed between the end of the first arc segment away from the straight edge segment and the end of the second arc segment away from the straight edge segment.

[0022] In some embodiments, the central angle of the first arc segment is greater than 90°; and / or the central angle of the second arc segment is greater than 90°.

[0023] In some embodiments, the distance between the end of the first arc segment away from the straight edge segment and the first connecting portion is greater than or equal to 1.4 mm; and / or the distance between the end of the second arc segment away from the straight edge segment and the first connecting portion is greater than or equal to 1.4 mm.

[0024] In some embodiments, the first fixing part includes a standing edge sub-part and a flange sub-part. The standing edge sub-part is connected to the first surface of the cover plate, and the flange sub-part is connected to the standing edge sub-part and bent relative to the standing edge sub-part to the side of the third sub-insulating part away from the cover plate.

[0025] In some embodiments, an insulating gap exists between the end of the flanged portion away from the upright portion and the second region, and a portion of the third sub-insulating portion fills the insulating gap.

[0026] In some embodiments, the third sub-insulation portion further covers the flanged sub-portion and at least part of the upright sub-portion; or the third sub-insulation portion does not cover the upright sub-portion and the flanged sub-portion.

[0027] In some embodiments, the orthographic projection of the flange portion on the cover plate along the thickness direction is the first orthographic projection, and the orthographic projection of the second connecting portion on the cover plate along the thickness direction is the second orthographic projection; the first orthographic projection and the second orthographic projection may partially overlap or not overlap.

[0028] In some embodiments, the pole post further includes a plurality of transition portions corresponding one-to-one with each of the second connecting portions, and each transition portion is connected between the first connecting portion and the corresponding second connecting portion.

[0029] In some embodiments, each transition portion has a second through hole; each second connecting portion includes a first region and a second region arranged around the first region, the second region being connected to the first connecting portion, the first region protruding relative to the second region in a direction from the first surface to the second surface, and forming a connecting sub-port that passes through the first through hole; the third insulating portion further includes a third sub-insulating portion and a fifth sub-insulating portion, the third sub-insulating portion at least partially covering the second region, the fifth sub-insulating portion filling the second through hole, and the fifth sub-insulating portion being connected to the first sub-insulating portion and the third insulating portion.

[0030] In some embodiments, the first sub-insulating portion, the third sub-insulating portion, and the fifth sub-insulating portion are integrally formed.

[0031] In some embodiments, the top cover assembly further includes a sealing ring, which includes a first sealing portion and a second sealing portion. Both the first sealing portion and the second sealing portion are sleeved on the connecting sub-part. The first sealing portion is located between the connecting sub-part and the inner wall of the first through hole, and the second sealing portion is located between the second region and the first surface of the cover plate.

[0032] In some embodiments, the first surface of the cover plate has a first protrusion surrounding the first through hole, and the second sealing portion abuts against the first protrusion.

[0033] In some embodiments, the sealing ring further includes a second protrusion that protrudes from the side of the second sealing portion away from the cover plate and is arranged around the second region.

[0034] In some embodiments, the second protrusion is C-shaped, and the opening of the second protrusion faces the first connecting portion.

[0035] In some embodiments, a fourth groove is provided on the side of the first connecting portion facing the cover plate, and a portion of the first sub-insulating portion is filled in the fourth groove.

[0036] In some embodiments, the fourth groove gradually narrows or tapers at least partially in the direction from the bottom of the groove to the opening of the groove.

[0037] In some embodiments, the depth dimension of the fourth groove is h1, and the thickness dimension of the first connecting part is H1, wherein h1 and H1 satisfy: h1 = (5% ~ 50%)H1.

[0038] In some embodiments, the surface of the cover plate facing the first connection portion has a third groove, and a portion of the first sub-insulator portion is filled in the third groove.

[0039] In some embodiments, the third groove gradually narrows or tapers from the bottom to the opening.

[0040] In some embodiments, the depth dimension of the third groove is h2, and the thickness dimension of the cover plate is T2, wherein h2 and T2 satisfy: h2 = (5% ~ 50%)T2.

[0041] In some embodiments, the first connecting portion has a first electrical connecting portion and a first stepped surface on the side away from the cover plate. The first stepped surface is arranged around the first electrical connecting portion, and the first electrical connecting portion protrudes in the direction away from the cover plate relative to the first stepped surface. The third insulating portion further includes a second sub-insulating portion, which is arranged around the first connecting portion and covers the peripheral edge of the first connecting portion. The surface of the second sub-insulating portion is flush with the first stepped surface.

[0042] In some embodiments, there are two second connecting portions, which are respectively located on both sides of the first connecting portion in the width direction of the cover plate; or each of the second connecting portions is located on the same side of the first connecting portion in the length direction of the cover plate, and the width direction of the cover plate is perpendicular to the length direction of the cover plate.

[0043] On the other hand, this application provides a battery cell including a housing, an electrode assembly, and a top cover assembly as described in any of the above embodiments; the housing has a receiving cavity and an opening communicating with the receiving cavity, a cover plate is disposed on the opening, the electrode assembly is disposed in the receiving cavity, and has at least two tabs on the side facing the cover plate, and each second connection portion extends through a first through hole into the receiving cavity and is connected to the corresponding tab.

[0044] On the other hand, this application provides a battery cell, including: a housing having a receiving cavity and a first wall serving as a side wall of the receiving cavity, the first wall having an inner side, an outer side, and a first through hole, the inner side facing the receiving cavity, the outer side facing away from the receiving cavity, and the first through hole penetrating the inner side and the outer side; an electrode assembly housed in the receiving cavity of the housing, and having at least two tabs on the side facing the first wall; a terminal post including a first connecting portion and at least two second connecting portions, the first connecting portion being disposed on the outer side of the first wall, each of the second connecting portions being connected to the first connecting portion and arranged along the width direction of the first wall; each second connecting portion being at least partially inserted into the first through hole and respectively connected to the corresponding tab; and a third insulating portion including a first sub-insulating portion disposed between the first connecting portion and the first wall.

[0045] On the other hand, this application provides a battery characterized by comprising a battery cell as described in any of the above embodiments. On the other hand, this application provides an electrical device comprising a battery cell as described in any of the above embodiments, or comprising a battery as described in any of the above embodiments.

[0046] Compared with the prior art, this application has the following beneficial effects:

[0047] The aforementioned top cover assembly, battery cell, battery, and power device have terminals that are directly connected to the tabs of the two sets of electrodes via two second connecting parts. This avoids the use of adapter plates, thereby reducing the number of parts in the top cover assembly and eliminating one welding process. Furthermore, by arranging the two second connecting parts along the arrangement direction of the two sets of electrodes, the two second connecting parts pass through the first through hole in the cover plate and are connected to the tabs of the two sets of electrodes respectively. This avoids the need to increase the radial dimension of the terminal and extend the tabs, thereby avoiding increased material costs for the tabs and the increased risk of adverse phenomena such as tabs being inserted backwards into the electrodes and tabs tearing.

[0048] Embodiments of this application also provide a top cover assembly, a battery cell, a battery, and an electrical device to solve the technical problem in the prior art where the limited design space of the top cover assembly leads to the limitation of the design size of the tabs and terminals, which is detrimental to improving battery performance.

[0049] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0050] In a first aspect, this application provides a top cover assembly, comprising: a cover plate, an electrode post, and a first insulating member. The cover plate has a first surface, a second surface, and a first through hole, wherein the first surface and the second surface are arranged facing away from each other, and the first through hole penetrates through the first surface and the second surface. The electrode post includes at least one first connecting portion and at least two second connecting portions, and each first connecting portion is connected to two adjacent second connecting portions. The at least two second connecting portions are spaced apart along the width direction of the cover plate. The first connecting portion is located on the side of the cover plate having the first surface and is used to connect with an electrical connector. At least a portion of the second connecting portion passes through the first through hole and is used to connect with a tab. The first insulating member is fixedly connected to the electrode post and the cover plate, and includes a first insulating portion, a second insulating portion, and a third insulating portion connected together. The first insulating portion is located on the side of the cover plate having the second surface. The second insulating portion is located between the hole wall of the first through hole and the second connecting portion of the electrode post. The third insulating portion is located on the side of the cover plate having the first surface. On a dummy plane perpendicular to the thickness direction of the cover plate, the orthographic projection of the first insulating portion overlaps with the orthographic projection of the cover plate.

[0051] In some embodiments, the second connecting portion has a first groove, and along the thickness direction of the cover plate, the opening of the first groove is formed on the surface of the second connecting portion near the first connecting portion, and the bottom surface of the first groove is located between the first surface and the second surface.

[0052] In some embodiments, the second connecting portion has a flanged portion around the opening of the first groove, and the flanged portion is located on the side of the cover plate having the first surface along the thickness direction of the cover plate.

[0053] In some embodiments, on a dummy plane perpendicular to the thickness direction of the cover plate, the orthographic projection of the flange overlaps with the orthographic projection of the cover plate.

[0054] In some embodiments, the second connecting portion includes a first metal layer and a second metal layer, which are stacked along the thickness direction of the second connecting portion, and at least a portion of the interface between the first metal layer and the second metal layer intersects with the sidewall surface of the flange portion.

[0055] In some embodiments, the width of the cover plate is W1 along the width direction, and the minimum distance between the side wall of the flange and the edge of the cover plate is W4, satisfying: 5% ≤ W4 / W1 ≤ 20%.

[0056] In some embodiments, along the width direction of the cover plate, the minimum distance between the side of the flange and the edge of the cover plate is W4, satisfying: 3mm≤W4≤10mm.

[0057] In some embodiments, the width of the cover plate is W1, which satisfies: W1≥20mm.

[0058] In some embodiments, the second connecting portion is a plate-like structure, and along the thickness direction of the cover plate, the second connecting portion has a third surface disposed near the first connecting portion, the third surface being located between the first surface and the second surface.

[0059] In some embodiments, the pole post further includes a transition portion, which connects the first connecting portion and the second connecting portion along the width direction of the cover plate, and at least a portion of the transition portion is projected onto the first through hole along the thickness direction of the cover plate.

[0060] In some embodiments, along the length direction of the cover plate, the length of the transition portion is less than the length of the first connecting portion and less than the length of the second connecting portion; the first through hole has a notch for accommodating the transition portion.

[0061] In some embodiments, the second connecting portion is a plate-like structure, and along the thickness direction of the cover plate, the second connecting portion has a third surface disposed near the first connecting portion, the third surface being flush with the first surface of the cover plate, or the third surface protruding from the first surface of the cover plate.

[0062] In some embodiments, the surfaces of the cover plate that are in contact with the first insulating portion and the second insulating portion are provided with first nanopores, and at least a portion of the first insulating portion and the second insulating portion are embedded in the first nanopores.

[0063] In some embodiments, the surfaces of the pole post that are in contact with the first insulating portion and the second insulating portion are provided with a second nanopore, and the first insulating portion and the second insulating portion are at least partially embedded in the second nanopore.

[0064] In some embodiments, on a dummy plane perpendicular to the thickness direction of the cover plate, the orthographic projection of the third insulating portion overlaps with the orthographic projection of the cover plate, and the surface of the cover plate in contact with the third insulating portion is provided with a third nanopore, and at least a portion of the third insulating portion is embedded in the third nanopore.

[0065] In some embodiments, the surface of the pole that contacts the third insulating portion is provided with a fourth nanopore, and at least a portion of the third insulating portion is embedded in the fourth nanopore.

[0066] In some embodiments, the first insulating portion, the second insulating portion, and the third insulating portion of the first insulating member are integrally formed.

[0067] In some embodiments, along the thickness direction of the cover plate, the orthographic projection of the first connecting part on the cover plate does not overlap with the first through hole, the outer contour of the first connecting part has at least a first outer peripheral surface, and along the width direction of the cover plate, the minimum distance between the first outer peripheral surface and the hole wall of the first through hole is W5, satisfying: 0≤W5≤10mm.

[0068] In some embodiments, along the thickness direction of the cover plate, the orthographic projection of the first connecting portion on the cover plate overlaps with the first through hole portion, the outer contour of the first connecting portion has at least a first outer peripheral surface, and along the width direction of the cover plate, the distance between the first outer peripheral surface and the hole wall of the first through hole is W5, satisfying: 0≤W5≤10mm.

[0069] In some embodiments, the first surface of the cover plate is provided with a second groove, which is recessed from the first surface to the second surface. The cover plate includes at least two first through holes, and each second connecting part is correspondingly disposed in a first through hole. The at least two first through holes respectively penetrate the bottom wall of the second groove along the thickness direction of the cover plate.

[0070] In some embodiments, the thickness of the cover plate along the thickness direction is T2, which satisfies: 1.5mm≤T2≤3mm.

[0071] In some embodiments, along the thickness direction of the cover plate, the groove depth of the second groove is T1, satisfying: 0.3mm≤T1≤1.5mm.

[0072] In some embodiments, along the thickness direction of the cover plate, the groove depth of the second groove is T1, and the thickness of the cover plate is T2, satisfying: 10% ≤ T1 / T2 ≤ 80%.

[0073] In some embodiments, the cover plate has a through hole along its thickness direction, and a support portion is provided in the through hole. The two ends of the support portion, which are arranged opposite to each other along its longitudinal direction, are respectively connected to the two side walls of the through hole, which are arranged opposite to each other along the length direction of the cover plate, and divide the through hole into two first through holes spaced apart along the width direction of the cover plate. The first surface of the cover plate protrudes from the support portion along its thickness direction.

[0074] In some embodiments, along the thickness direction of the cover plate, the support portion has a fourth surface close to the first surface, and the distance between the fourth surface of the support portion and the first surface is T3, satisfying: 0.3mm≤T3≤1.5mm.

[0075] In some embodiments, along the thickness direction of the cover plate, the thickness of the cover plate is T2, and the distance between the fourth surface and the first surface of the support is T3, satisfying: 10% ≤ T3 / T2 ≤ 80%.

[0076] In some embodiments, along the thickness direction of the cover plate, the surface of the first connecting portion near the cover plate is the fifth surface, the first surface of the cover plate is provided with a second groove, and the distance between the fifth surface and the bottom wall of the second groove is W6, satisfying: 0.5mm≤W6≤1.2mm.

[0077] In some embodiments, the cover plate has a through hole along its thickness direction, and a support portion is provided in the through hole. The two ends of the support portion, which are arranged opposite to each other along its longitudinal direction, are respectively connected to the two side walls of the through hole, which are arranged opposite to each other along the length direction of the cover plate, and divide the through hole into two first through holes spaced apart along the width direction of the cover plate. The side surface of the support portion near the first connecting portion is the fourth surface, and the distance between the fifth surface and the fourth surface of the support portion is W6, which satisfies: 0.5mm≤W6≤1.2mm.

[0078] In some embodiments, along the width direction of the cover plate, the maximum width of the first connecting portion is W2, and the width of the cover plate is W1, satisfying: 20% ≤ W2 / W1 ≤ 60%.

[0079] In some embodiments, the maximum width of the first connecting portion along the width direction of the cover plate is W2, which satisfies: 8mm≤W2≤35mm.

[0080] In some embodiments, the width of the cover plate is W1 along the width direction, satisfying: W1≥20mm.

[0081] In some embodiments, the outer contour of the first connecting portion has at least a first outer peripheral surface, and the minimum distance between the first outer peripheral surface and the edge of the cover plate along the width direction of the cover plate is W3, and the width of the cover plate is W1, satisfying: 25% ≤ W3 / W1 ≤ 40%.

[0082] In some embodiments, the third insulating portion covers the surface of the pole located on the side of the first face and exposes at least the first electrical connection surface of the first connection portion.

[0083] In some embodiments, the outer circumferential edge of the third insulating portion is set at an obtuse angle to the first surface of the cover plate.

[0084] In some embodiments, the first surface of the cover plate is provided with a second groove, and the distance between the outer edge of the third insulating part and the groove sidewall of the second groove is a, which satisfies: 0.3mm≤a≤2mm.

[0085] In some embodiments, the device further includes: a second insulating member disposed on one side of the cover plate having a second surface; the second insulating member having a second through hole corresponding to the first through hole; the second through hole penetrating the thickness direction of the second insulating member; the second connecting portion passing through the first through hole and the second through hole in sequence; the circumferential outer edge of the first insulating portion having a first inclined structure; the second insulating member having a second inclined structure matching the first inclined structure; and the second inclined structure abutting against the first inclined structure.

[0086] In some embodiments, the surface of the second insulating member facing away from the cover plate is aligned with the surface of the first insulating portion facing away from the cover plate.

[0087] In some embodiments, the second connecting portion includes a third sub-portion and a fourth sub-portion. Along the thickness direction of the cover plate, and on a plane perpendicular to the thickness direction of the cover plate, the orthographic projection of the fourth sub-portion falls within the orthographic projection range of the third sub-portion. A second stepped surface connects the sidewall surface of the fourth sub-portion and the sidewall surface of the third sub-portion. The end surface of the fourth sub-portion away from the third sub-portion is a second electrical connection surface. The second stepped surface is flush with the surface of the first insulating portion away from the cover plate.

[0088] Secondly, this application also provides a battery cell, comprising: a housing, an electrode assembly, and a top cover assembly according to any one of the first aspects, wherein the housing has an opening; the electrode assembly has tabs and is received within the housing; and the top cover assembly covers the opening of the housing. Thirdly, this application also provides a battery, comprising the battery cell of the second aspect.

[0089] Fourthly, this application also provides an electrical device, including a battery cell of the second aspect or a battery of the third aspect.

[0090] Based on the above technical solution, the top cover assembly, battery cell, battery, and power device of this application have at least the following beneficial technical effects:

[0091] The top cover assembly provided in this application embodiment includes a first insulating part comprising a first insulating part, a second insulating part, and a third insulating part. The first insulating part is positioned on the side of the cover plate facing the electrode assembly, and its projection along the thickness of the cover plate falls on the cover plate. Therefore, at least a portion of the first insulating part bends below the wall of the first through hole towards the inner side of the cover plate and connects to the lower surface of the cover plate. This improves the fixation effect on the electrode post and insulates the lower surface of the cover plate from the electrode post, simultaneously providing a seal to prevent electrolyte leakage from the first through hole. The second insulating part is positioned between the wall of the first through hole in the cover plate and the second connecting part of the electrode post, further insulating the wall of the first through hole and the electrode post, and also providing a seal to prevent electrolyte leakage from the first through hole. The third insulating part is positioned on the cover plate... The surface facing the outer side of the housing is aligned with the upper surface of the insulating cover and the terminal post. The first insulating member in this embodiment of the application has the functions of fixing, insulating and sealing. Therefore, the sealing ring structure in the top cover assembly of related technologies can be eliminated. Thus, in the width direction of the cover plate, the size of the sealing ring is no longer considered. Only the size of the outer film of the housing at the edge of the cover plate to the edge of the first insulating member, the size of the two second connecting parts and the size of the first connecting part need to be considered. Even for battery cells with small thickness and limited design width of the cover plate, the weldable area of ​​the first connecting part and the weldable area of ​​the second connecting part can be guaranteed, so as not to affect the charging and discharging performance and safety performance of the battery. In other words, when the size of the terminal post in the width direction of the cover plate is fixed, the weldable area of ​​the first connecting part and the weldable area of ​​the second connecting part can be increased.

[0092] The battery cell provided in this application includes a top cover assembly. Since the top cover assembly eliminates the sealing ring structure, the width of the top cover assembly can be adapted and applied to battery cells with smaller thickness, thereby improving the charging and discharging performance and safety performance of the battery cell. In other words, when the width of the top cover assembly is fixed, the weldable area of ​​the first connection part and the weldable area of ​​the second connection part can be increased, thereby improving the charging and discharging performance and safety performance of the battery cell. Attached Figure Description

[0093] Figure 1 is a three-dimensional structural diagram of a battery cell provided in an embodiment of this application.

[0094] Figure 2 is a schematic diagram of the front view structure of a battery cell provided in an embodiment of this application.

[0095] Figure 3 is a cross-sectional view of AA in Figure 2.

[0096] Figure 4 is a cross-sectional view of BB in Figure 2.

[0097] Figure 5 is a three-dimensional structural diagram of the top cover assembly provided in an embodiment of this application.

[0098] Figure 6 is a schematic diagram of the exploded disassembly structure of the top cover assembly provided in an embodiment of this application.

[0099] Figure 7 is a side view of the top cover assembly provided in an embodiment of this application.

[0100] Figure 8 is a cross-sectional view of BB in Figure 7.

[0101] Figure 9 is a three-dimensional structural diagram of the pole post in the top cover assembly provided in the embodiment of this application.

[0102] Figure 10 is a side view of the pole post in the top cover assembly provided in an embodiment of this application.

[0103] Figure 11 is a three-dimensional structural diagram of the pole post in the top cover assembly provided in another embodiment of this application.

[0104] Figure 12 is a side view of the pole post in the top cover assembly provided in another embodiment of this application.

[0105] Figure 13 is a three-dimensional structural diagram of the first insulating element in the top cover assembly provided in the embodiment of this application.

[0106] Figure 14 is a cross-sectional view of the first insulating member in the top cover assembly provided in the embodiment of this application on a plane perpendicular to its length direction.

[0107] Figure 15 is a cross-sectional view of the first insulating member in the top cover assembly provided in the embodiment of this application on a plane perpendicular to its width direction.

[0108] Figure 16 is a cross-sectional view of AA in Figure 7.

[0109] Figure 17 is a three-dimensional structural diagram of the pole post in the top cover assembly provided in another embodiment of this application.

[0110] Figure 18 is a side view of the pole post in the top cover assembly provided in another embodiment of this application.

[0111] Figure 19 is a three-dimensional structural schematic diagram of the first insulating member in the top cover assembly provided in another embodiment of this application.

[0112] Figure 20 is a cross-sectional view of the first insulating member in the top cover assembly provided in another embodiment of this application on a plane perpendicular to its length direction.

[0113] Figure 21 is a cross-sectional view of the first insulating member in the top cover assembly provided in another embodiment of this application on a plane perpendicular to its width direction.

[0114] Figure 22 is a partial structural schematic diagram of the cover plate of the top cover assembly provided in an embodiment of this application.

[0115] Figure 23 is a partial structural schematic diagram of the cover plate of the top cover assembly provided in an embodiment of this application.

[0116] Figure 24 is a three-dimensional structural diagram of a battery cell provided in another embodiment of this application.

[0117] Figure 25 is a front view structural diagram of a battery cell provided in another embodiment of this application.

[0118] Figure 26 is a CC cross-sectional view from Figure 25.

[0119] Figure 27 is a three-dimensional structural schematic diagram of the top cover assembly provided in another embodiment of this application.

[0120] Figure 28 is an exploded structural diagram of the top cover assembly provided in another embodiment of this application.

[0121] Figure 29 is a side view of a top cover assembly provided in another embodiment of this application.

[0122] Figure 30 is a CC cross-sectional view of Figure 29.

[0123] Figure 31 is a side view of the pole post in the top cover assembly provided in another embodiment of this application.

[0124] Figure 32 is a cross-sectional view of a top cover assembly provided in another embodiment of this application.

[0125] Figure 33 is a cross-sectional view of a top cover assembly provided in another embodiment of this application.

[0126] Figure 34 is a cross-sectional view of a top cover assembly provided in another embodiment of this application.

[0127] Figure 35 is a cross-sectional view of a top cover assembly provided in another embodiment of this application;

[0128] Figure 36 is a cross-sectional view of a battery cell at the terminal post in one embodiment of this application (the cross-section is perpendicular to the length direction of the cover plate);

[0129] Figure 37 is a schematic diagram of the top cover assembly of the battery cell shown in Figure 36;

[0130] Figure 38 is an exploded structural diagram of the top cover assembly shown in Figure 37;

[0131] Figure 39 is a cross-sectional view of the top cover assembly shown in Figure 37 (the cross-section is perpendicular to the length direction of the cover plate);

[0132] Figure 40 is a schematic diagram of the pole structure of the top cover assembly shown in Figure 37;

[0133] Figure 41 is a cross-sectional view of the pole shown in Figure 40 (the cross-section is perpendicular to the length direction of the cover plate);

[0134] Figure 42 is a schematic diagram of the sealing ring structure of the top cover assembly shown in Figure 37;

[0135] Figure 43 is a schematic diagram of the cover plate of the top cover assembly shown in Figure 37;

[0136] Figure 44 is a structural schematic diagram of the first insulating component of the top cover assembly shown in Figure 37;

[0137] Figure 45 is a cross-sectional view of the top cover assembly at the pole post in another embodiment of this application (the cross-section is perpendicular to the length direction of the cover plate).

[0138] The above figures include the following reference numerals:

[0139] 10. Cover plate; 11. First surface; 12. Second surface; 13. First through hole; 14. Second groove; 15. Support part; 16. Notch; 20. Pole post; 21. First connecting part; 22. Second connecting part; 23. Flanged part; 24. First groove; 25. Transition part; 30. First insulating component; 31. First insulating part; 32. Second insulating part; 33. Third insulating part; 40. Second insulating component; 41. Second through hole; 43. Second inclined structure; 50. Pressure relief mechanism; 60. Protection Layer; 100, Top cover assembly; 101, First outer peripheral surface; 102, First electrical connection surface; 103, Fifth surface; 104, First stepped surface; 105, Third stepped surface; 151, Fourth surface; 152, Sixth surface; 200, Housing; 201, Second outer peripheral surface; 202, Third surface; 203, Second stepped surface; 204, Second electrical connection surface; 205, Third sub-part; 206, Fourth sub-part; 211, Base part; 212, First electrical connection part; 240, Second electrical connection part; 25 1. First arc segment; 252. First straight segment; 253. Second arc segment; 221. First metal layer; 222. Second metal layer; 300. Electrode assembly; 301. Tab; 311. First inclined structure; 331. First sub-insulating part; 332. Second sub-insulating part; 333. Third sub-insulating part; 334. Fourth sub-insulating part; 2121. First sub-part; 2122. Second sub-part; 223. Connecting sub-part; a3. Welding end; a4. Welding surface; 227. Protrusion; 254. Three-way hole; 335, fifth sub-insulating part; 361, pit; 70, first fixing part; 71, upright edge part; 73, flanged edge part; 730, insulation gap; 75, first arc segment; 77, straight edge segment; 79, second arc segment; a6, stepped surface; a5, clearance space; 224, first area; 225, second area; 17, third groove; 18, first convex strip; 210, fourth groove; 80, sealing ring; 81, first sealing part; 82, second sealing part; 83, second convex strip. Detailed Implementation

[0140] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0141] In related technologies, adapter plates are used to connect the positive tabs to the positive terminals on the top cover assembly. However, the presence of adapter plates increases the number of parts, leading to higher costs for individual battery cells, increased internal resistance, and reduced energy efficiency. Furthermore, the addition of a welding process between the tabs and the adapter plate further increases the cost of the battery cell. To overcome these drawbacks, adapter-free solutions have been developed.

[0142] In the adapter-less technical solution, the positive terminal on the top cover assembly extends directly into the receiving cavity and connects directly to the positive tabs of each set of electrode assemblies. However, since each set of electrode assemblies is arranged along the thickness direction of the housing, the positive tabs of each set of electrode assemblies are also arranged along the thickness direction of the housing. Because the span of each positive tab in the thickness direction of the housing is relatively large, the positive tabs need to be arranged in the middle of the thickness direction of the housing. Therefore, a positive terminal of conventional size cannot be directly connected to each positive tab. Therefore, in order to achieve direct connection between the positive terminal and each positive tab, one method is to increase the radial dimension of the terminal, so that the terminal is as close as possible to the positive tabs on both sides in the thickness direction of the housing, ensuring that each positive tab can be directly connected to the positive terminal; another method is to extend the length of the positive tab, so that each positive tab extends to the positive terminal and connects directly to the positive terminal.

[0143] However, during long-term research and development, the inventors of this application discovered that in the scheme of increasing the radial dimension of the electrode post, the material cost of the electrode post increases with the increase of the radial dimension, and the size of the mounting hole used to install the electrode post is larger, resulting in insufficient strength of the cover plate of the top cover assembly. In the scheme of extending the length of the positive electrode tab, the risk of the electrode tab being inserted backward into the electrode assembly and the electrode tab tearing increases. It should be noted that the same defects exist when the negative electrode post is directly connected to the negative electrode tab, which will not be elaborated here.

[0144] To overcome the aforementioned shortcomings, the inventors of this application have creatively proposed an electrode post capable of directly connecting the electrode post and the electrode tab. In the technical solution of this application, the electrode post is formed from sheet metal through a stamping process (e.g., upsetting, drawing, and cutting). The electrode post includes a first connecting portion and at least two second connecting portions connected to the first connecting portion, the at least two second connecting portions being arranged along the thickness direction of the shell. That is, the arrangement direction of each second connecting portion is consistent with the arrangement direction of each group of electrode assemblies, so that each second connecting portion is one-to-one with the electrode tab of each group of electrode assemblies, thereby the electrode tab of each group of electrode assemblies is directly connected to its corresponding second connecting portion, thus avoiding the need to increase the radial dimension of the electrode post or extend the length of the electrode tab, and thus overcoming the shortcomings caused by increasing the radial dimension of the electrode post and extending the electrode tab.

[0145] The technical solutions provided in this application are applicable to top cover assemblies, battery cells including top cover assemblies, batteries including battery cells, and electrical devices using the battery as a power source.

[0146] The electrical devices disclosed in this application can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, power tools, energy storage devices, amusement equipment, elevators and lifting equipment, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, or electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices can be energy storage walls, base station energy storage, container energy storage, etc.; amusement equipment can be carousels, drop towers, etc.

[0147] This application describes an electrical device using a vehicle as an example. The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery is installed inside the vehicle, and the battery can be located at the bottom, front, or rear of the vehicle. The battery can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The vehicle may also include a controller and a motor. The controller controls the battery to supply power to the motor, for example, to meet the power needs of starting, navigation, and driving the vehicle. The battery can not only serve as the vehicle's operating power source but also as its driving power source, replacing or partially replacing gasoline or natural gas to provide driving power to the vehicle.

[0148] The aforementioned battery can be a battery pack or a battery module. When the battery is a battery pack, the battery pack specifically includes a battery management system (BMS) and multiple battery cells. Multiple battery cells can be electrically connected in series, parallel, or a combination of series and parallel connections, and communicate with the battery management system, which controls and monitors the operating status of each battery cell. Alternatively, multiple battery cells can first be combined with a module management system to form a battery module, and then these battery modules can be electrically connected in series, parallel, or a combination of series and parallel connections to form a battery pack together with the battery management system.

[0149] Multiple battery cells can be mounted on supporting structures such as housings, frames, and brackets. Electrical connections between battery cells and between battery cells and the battery management system can be established via electrical connectors, which can be busbars. Alternatively, battery cells can be electrically connected by plugging in their respective terminals. For example, between two adjacent battery cells, one battery cell has a slot on its terminal, and the other battery cell has a corresponding insert on its terminal. The insert is inserted into the slot to achieve electrical connection. Therefore, for one battery cell, the aforementioned electrical connector can be the terminal of another battery cell. Similarly, battery cells and the battery management system can also be electrically connected by plugging in each other, which will not be elaborated further here.

[0150] The aforementioned battery cell can be a secondary battery or a primary battery, and can also be a lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery. Its external outline can be cylindrical, flat, cuboid, or other shapes, but is not limited to these. Specifically, in this embodiment, the aforementioned battery cell is a lithium-ion square battery.

[0151] As one embodiment of a battery cell, please refer to Figures 1, 2, 3, 4, 24, 25, and 26. A battery cell refers to the smallest unit that makes up a battery. As shown in Figures 3 and 4 or Figure 26, the battery cell includes a housing 200, an electrode assembly 300, a top cover assembly 100, and other functional components. At least one end of the housing 200 has an opening, and the top cover assembly 100 covers the opening of the housing 200 to isolate the internal environment of the battery cell from the external environment. The housing 200 has a receiving cavity inside to accommodate the electrode assembly 300 within the receiving cavity of the housing 200. The housing 200 is an assembly used to cooperate with the top cover assembly 100 to form the internal environment of the battery cell, wherein the formed internal environment can be used to accommodate the electrode assembly 300, electrolyte, and other components. The housing 200 and the top cover assembly 100 can be independent components, and an opening can be provided on the housing 200. The internal environment of the battery cell is formed by the top cover assembly 100 covering the opening. The housing 200 can have various shapes and sizes, such as cylindrical, cuboid, hexagonal prism, etc. Specifically, the shape of the housing 200 can be determined according to the specific shape and size of the electrode assembly 300. The housing 200 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0152] As one embodiment of an electrode assembly, the electrode assembly 300 is a component in a battery cell that undergoes an electrochemical reaction with the electrolyte. The housing 200 may contain one or more electrode assemblies 300. The electrode assembly 300 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. During the charging and discharging process of the battery cell, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrode sheets. The separator, disposed between the positive and negative electrode sheets, can reduce short circuits between the positive and negative electrodes while allowing active ions to pass through. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected. The positive electrode sheet may include a positive current collector and positive active material layers coated on opposite sides of the positive current collector. The negative electrode sheet may include a negative current collector and negative active material layers coated on opposite sides of the negative current collector. The portions of the positive and negative electrode plates containing active material constitute the main body of the electrode assembly, while the portions of the positive and negative electrode plates without active material each constitute a tab. The positive and negative tabs can be located together at one end of the main body or at opposite ends of the main body. The electrode assembly 300 is covered with an insulating film to reduce the risk of short circuits.

[0153] In some embodiments, each electrode assembly 300 extends a positive electrode tab and a negative electrode tab to the end face of the top cover assembly 100, respectively. During the charging and discharging process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the electrode tabs are connected to the terminal post 20 to form a current loop.

[0154] In this embodiment, as shown in Figures 3 and 4 or Figure 26, the housing 200 includes two sets of electrode assemblies 300. Each set of electrode assemblies 300 includes one electrode assembly 300, and the two sets of electrode assemblies 300 are arranged side-by-side along the thickness direction of the housing 200. The two sets of positive electrode tabs of the two sets of electrode assemblies 300 are arranged opposite each other as positive electrodes, and the two sets of negative electrode tabs of the two sets of electrode assemblies 300 are arranged opposite each other as negative electrodes. The two sets of positive electrode tabs and the two sets of negative electrode tabs are spaced apart along the length direction of the housing 200. In other embodiments, the housing 200 may include at least two sets of electrode assemblies 300. Each set of electrode assemblies 300 may be one electrode assembly 300 or multiple electrode assemblies 300, which is not limited here. When each set of electrode assemblies 300 includes multiple electrode assemblies 300, the positive electrode tabs of each electrode assembly 300 are brought together to form one set of positive electrode tabs, and the negative electrode tabs are brought together to form one set of negative electrode tabs.

[0155] It should be noted that the length direction of the housing 200 is also the length direction of the top cover assembly 100 or the length direction of the electrode assembly 300, the thickness direction of the housing 200 is also the width direction of the top cover assembly 100 or the thickness direction of the electrode assembly 300, and the height direction of the housing 200 is also the height direction of the electrode assembly 300 or the thickness direction of the cover plate 10.

[0156] Before the electrode assembly 300 is installed into the housing 200, the electrode tabs 301 of the electrode assembly 300 are first assembled with the top cover assembly 100, for example, by welding the electrode post 20 of the top cover assembly 100 to the electrode tabs 301 of the electrode assembly 300, and then the electrode assembly 300 is installed into the housing 200.

[0157] The structure of the top cover assembly 100 is described below.

[0158] Referring to Figures 5 and 6 or Figures 27 and 28, the top cover assembly 100 includes a cover plate 10, which covers the opening of the housing 200. The shape of the cover plate 10 can be adapted to the shape of the housing 200 to fit the opening. The cover plate 10 can be made of a material with a certain hardness and strength (such as aluminum alloy or aluminum), so that the cover plate 10 is not easily deformed under pressure or impact, enabling the battery cell to have higher structural strength and improved safety performance. The material of the cover plate 10 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0159] Referring to Figures 5, 6, 22, 23, or 28, the cover plate 10 has a first surface 11, a second surface 12, and a first through hole 13. The first surface 11 and the second surface 12 are arranged opposite to each other along the thickness direction of the cover plate 10, and the first through hole 13 penetrates both the first surface 11 and the second surface 12. The first surface 11 can be the surface of the cover plate 10 facing the outside of the housing 200, and the second surface 12 can be the surface of the cover plate 10 facing the inside of the housing 200. The first through hole 13 is used to install functional components, such as poles.

[0160] In some embodiments, as shown in FIG8, FIG16, or FIG30, the width of the cover plate 10 is W1, satisfying: W1 ≥ 20 mm. For example, W1 is located in multiple ranges such as 20 mm ≤ W1 ≤ 45 mm, 20 mm ≤ W1 ≤ 60 mm, etc. Specifically, the width W1 of the cover plate 10 can be 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, or 60 mm, etc., including but not limited to the listed values, and other values ​​between any two of the above still apply. The width of the cover plate 10 can be understood as the distance between two sides along the width direction of the cover plate 10, which is used for welding connection with the housing 200. The cover plate 10 of the embodiments of this application can be applied to the housing 200 of a corresponding thickness and cover the opening of the housing 200.

[0161] As shown in Figures 8, 16, or 30, the thickness of the cover plate 10 along its thickness direction is T2, satisfying 1.5mm ≤ T2 ≤ 3mm. For example, T2 can be located within multiple intervals such as 1.8mm ≤ T2 ≤ 2.5mm, 1.5mm ≤ T2 ≤ 2mm, and 2mm ≤ T2 ≤ 3mm. Specifically, T2 can be 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, or 3.0mm, including but not limited to the listed values. Other values ​​between any two of the above are still applicable. The thickness of the cover plate 10 can be understood as the distance between the first surface 11 and the second surface 12 of the cover plate 10. By setting the thickness of the cover plate 10 within the above-mentioned range, the cover plate 10 has a certain hardness and strength, making it less prone to deformation when subjected to compression and impact, while improving the space utilization rate of the battery cell.

[0162] The cover plate 10 may be provided with functional components such as pole post 20, first insulating element 30, second insulating element 40, and pressure relief mechanism 50. The cover plate 10 and the functional components such as pole post 20, first insulating element 30, second insulating element 40 and pressure relief mechanism 50 provided on the cover plate 10 together constitute the top cover assembly 100.

[0163] The terminal 20 can be electrically connected to the electrode assembly 300 for outputting or inputting electrical energy into the battery cell. The terminal 20 includes a positive terminal and a negative terminal. The positive terminal is connected to the positive electrode tab, thereby introducing the positive current of the battery cell into the interior of the housing 200 or leading it out to the exterior of the housing 200. The negative terminal is connected to the negative electrode tab, thereby introducing the negative current of the battery cell into the interior of the housing 200 or leading it out to the exterior of the housing 200. The positive and negative terminals of adjacent battery cells can be electrically connected in series, parallel, or in a mixed configuration using electrical connectors.

[0164] It should be noted that the "terminal 20" mentioned in this application can be either a positive terminal or a negative terminal (unless otherwise specified). The "tab 301" mentioned in this application can be either a positive tab or a negative tab (unless otherwise specified), as long as the tab connected to the positive terminal is the positive tab and the tab connected to the negative terminal is the negative tab.

[0165] Specifically, referring to Figures 9, 11, or 17, the pole post 20 includes at least one first connecting portion 21 and at least two second connecting portions 22. The first connecting portion 21 is disposed on the side of the cover plate 10 having a first surface 11, so that the first connecting portion 21 can be connected to an electrical connector. At least a portion of the second connecting portion 22 passes through the first through hole 13, so that the second connecting portion 22 can be connected to the tab 301.

[0166] It is understood that the number of second connecting parts 22 is not limited to two, but can also be three, four or more. The number of second connecting parts 22 can correspond to the number of electrode assemblies 300 within the housing 200, so that each second connecting part 22 is respectively connected to a set of electrode tabs 301.

[0167] When the number of electrode assemblies 300 disposed within the housing 200 is N, the number of second connecting parts 22 is also set to N, where N is an integer greater than 1. The N second connecting parts 22 are spaced apart along the width direction of the cover plate 10 and connected to the first connecting parts 21. The N second connecting parts 22 pass through the first through hole 13 and are correspondingly connected to the tabs 301 of each group of electrode assemblies 300.

[0168] The second connecting part 22 in this embodiment can be directly welded to the tab 301. Therefore, at least a portion of the second connecting part 22 passes through the first through hole 13 and extends into the housing 200 to be directly connected to the tab 301. No adapter structure is required, which reduces the use of components, lowers the cost of the battery cell, and at the same time reduces the internal resistance of the battery cell and improves the energy density of the battery cell.

[0169] In some other embodiments, the number of first connecting portions 21 is not limited to one, but can be two or more. The number of first connecting portions 21 is related to the number of second connecting portions 22. A first connecting portion 21 is provided between two adjacent second connecting portions 22. For example, when the number of second connecting portions 22 is 2, the number of first connecting portions 21 is 1. When the number of second connecting portions 22 is 3, the number of first connecting portions 21 is 2. When the number of second connecting portions 22 is 4, the number of first connecting portions 21 is 3, and so on. The second connecting portions 22 and the first connecting portions 21 are arranged alternately along the width direction of the cover plate 10. For example, when the number of second connecting portions 22 is 3 and the number of first connecting portions 21 is 2, the pole post 20 includes, along the width direction of the cover plate 10, a second connecting portion 22, a first connecting portion 21, a second connecting portion 22, a first connecting portion 21, and a second connecting portion 22 connected in sequence.

[0170] In this embodiment, two sets of electrode assemblies 300 are provided inside the housing 200, and each set of electrode assemblies 300 includes one electrode assembly 300. Since two electrode assemblies 300 can be provided inside the housing 200 along the thickness direction, the two electrode assemblies 300 can extend positive electrode tabs and negative electrode tabs at the same end. The two sets of positive electrode tabs are arranged at intervals along the thickness direction of the electrode assembly 300, which is also the width direction of the top cover assembly 100. The two sets of negative electrode tabs are arranged at intervals along the thickness direction of the electrode assembly 300. The two sets of positive electrode tabs and the two sets of negative electrode tabs are arranged at intervals along the length direction of the electrode assembly 300. Therefore, each pole post 20 is provided with two second connecting parts 22 and one first connecting part 21. The two second connecting parts 22 are arranged at intervals along the width direction of the cover plate 10 so as to be directly connected to each set of tabs 301 (one of the second connecting parts 22 is connected to a set of tabs 301 formed by two sets of positive tabs, and the other second connecting part 22 is connected to another set of tabs 301 formed by two sets of negative tabs). One first connecting part 21 is connected to the adjacent second connecting parts 22 on both sides along the width direction of the cover plate 10 so as to output the current drawn from the two second connecting parts 22 through one first connecting part 21. Compared with each second connecting part 22 corresponding to a first connecting part 21, the size and space occupied by the pole post 20 can be greatly reduced, saving materials and costs, and also facilitating processing.

[0171] As shown in Figure 6 or Figure 28, the cover plate 10 may have a first through hole 13 corresponding to each second connecting part 22, so that each second connecting part 22 passes through the first through hole 13 and is connected to the corresponding tab 301. It is understood that the number of first through holes 13 can be the same as the number of second connecting parts 22. In other embodiments, the size of the first through hole 13 may also allow two second connecting parts 22 to pass through.

[0172] Referring to Figures 9, 10, and 11, as an embodiment of the pole post 20, the first connecting portion 21 of the pole post 20 includes a base portion 211 and a first electrical connection portion 212, which are integrally formed. The base portion 211 and the first electrical connection portion 212 are stacked along the thickness direction of the first connecting portion 21, and the cross-sectional area of ​​the base portion 211 is larger than the cross-sectional area of ​​the first electrical connection portion 212. The thickness direction of the first connecting portion 21 is consistent with the thickness direction of the cover plate 10. The first electrical connection portion 212 is located on the side of the base portion 211 facing the outside of the housing 200, and is used to connect with an electrical connector. The base portion 211 can be connected to a second connecting portion 22. The outer contour of the first connecting portion 21 has at least a first outer peripheral surface 101. Specifically, the first outer peripheral surface 101 is formed on the circumferential outer side surface of the base portion 211. When a portion of the circumferential outer side surface of the base portion 211 is flush with the circumferential outer side surface of the first electrical connection portion 212, that is, when they are the same outer side surface, the first outer peripheral surface 101 can also be the circumferential outer side surface of the first electrical connection portion 212. It is understood that the "circumferential" mentioned in the embodiments of this application can be the outer contour of the structural member on a plane perpendicular to the thickness direction of the pole post 20 or the cover plate 10.

[0173] As shown in Figures 9 and 11, the first connecting portion 21 includes a first electrical connection surface 102 and a fifth surface 103 disposed opposite to the first electrical connection surface 102. The first electrical connection surface 102 is a welding surface for welding with an electrical connector, and the solder joint between the electrical connector and the first electrical connection surface 102 can extend from the first electrical connection surface 102 into the interior of the first electrical connection portion 212. The fifth surface 103 can be the surface of the base portion 211 facing the interior of the housing.

[0174] As shown in Figures 9 and 11, the first electrical connection portion 212 includes a first sub-portion 2121 and a second sub-portion 2122. Along the thickness direction of the cover plate 10, one end of the first sub-portion 2121 is connected to the base portion 211, and the opposite end is connected to the second sub-portion 2122. It can be understood that the second sub-portion 2122 and the first sub-portion 2121 are stacked along the thickness direction of the cover plate 10. Along the thickness direction of the cover plate 10, the orthographic projection of the second sub-portion 2122 onto the cover plate 10 falls within the orthographic projection range of the first sub-portion 2121 onto the cover plate 10; that is, the cross-sectional area of ​​the second sub-portion 2122 is smaller than the cross-sectional area of ​​the first sub-portion 2121. Therefore, a first stepped surface 104 connects the sidewalls of the first sub-portion 2121 and the second sub-portion 2122. The surface of the second sub-portion 2122 away from the first sub-portion 2121 is the first electrical connection surface 102.

[0175] A first stepped surface 104 is formed around a first electrical connection surface 102. Along the thickness direction of the first connecting portion 21, the first electrical connection surface 102 protrudes from the first stepped surface 104, meaning the first stepped surface 104 is positioned closer to the base portion 211 than the first electrical connection surface 102. In this embodiment, as shown in Figures 9 and 11, at least a third stepped surface 105 is also formed around the first electrical connection portion 212 in the base portion 211. The third stepped surface 105 is formed between the sidewall of the base portion 211 and the sidewall of the first sub-portion 2121 in the length direction of the base portion 211, which is also the length direction of the cover plate 10. At this time, both the first stepped surface 104 and the first electrical connection surface 102 protrude from the third stepped surface 105.

[0176] The first stepped surface 104 creates a distance between the edge of the first insulating member 30 connected to the outside of the first sub-part 2121 and the first electrical connection surface 102, preventing interference with the first electrical connection surface 102 and thus avoiding affecting the welding quality between the first electrical connection surface 102 and the electrical connector. It is understood that during injection molding of the first insulating member 30, the first stepped surface 104 prevents plastic material from overflowing onto the first electrical connection surface 102 and affecting the welding quality.

[0177] As another embodiment of the first connecting portion 21 of the pole post 20, as shown in FIG17, a first stepped surface 104 is formed between the side wall surface of the base portion 211 of the first connecting portion 21 of the pole post 20 and the side wall surface of the first electrical connection portion 212. In this embodiment, along the thickness direction of the first connecting portion 21, the cross-sectional area of ​​the base portion 211 is the same as the cross-sectional area of ​​the first sub-portion 2121 of the first electrical connection portion 212, therefore there is no third stepped surface 105 between the base portion 211 and the first sub-portion 2121.

[0178] In some embodiments, referring to Figures 8, 12, 16, 18, or 30, the maximum width of the first connecting portion 21 along the width direction of the cover plate 10 is W2. The relationship between the maximum width W2 of the first connecting portion 21 and the width W1 of the cover plate 10 satisfies: 20% ≤ W2 / W1 ≤ 60%. For example, W2 / W1 can be located within multiple intervals such as 30% ≤ W2 / W1 ≤ 50%, 20% ≤ W2 / W1 ≤ 40%, 40% ≤ W2 / W1 ≤ 60%, 30% ≤ W2 / W1 ≤ 40%, and 40% ≤ W2 / W1 ≤ 50%. Specifically, W2 / W1 = 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60%, etc., including but not limited to the values ​​listed above. Other values ​​between any two of the above are still applicable. The maximum width W2 of the first connecting portion 21 refers to the distance between the opposite first outer peripheral surfaces 101 along its width direction, i.e., along the width direction of the cover plate 10. This arrangement ensures that the first connecting portion 21 has sufficient welding area, while also reserving a certain size for the welding area of ​​the second connecting portion 22 and for the outer casing film to be folded at the edge of the cover plate 10 to the edge of the first insulating member 30.

[0179] Along the width direction of the cover plate 10, the maximum width of the first connecting portion 21 is W2, satisfying: 8mm≤W2≤35mm. For example, W2 can be located within multiple intervals such as 8mm≤W1≤25mm, 8mm≤W1≤15mm, 15mm≤W2≤25mm, 8mm≤W2≤20mm, 20mm≤W2≤35mm, 18mm≤W2≤22mm, etc. Specifically, W2 = 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 15mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 25mm, 27mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, or 35mm, including but not limited to the values ​​listed above. Other values ​​between any two of the above still apply. This arrangement ensures that the first connecting portion 21 has sufficient welding area.

[0180] Referring to Figures 8, 16, or 30, along the width direction of the cover plate 10, the minimum distance between the first outer peripheral surface 101 of the first connecting portion 21 and the edge of the cover plate 10 is W3. The relationship between W3 and the width W1 of the cover plate 10 satisfies: 25% ≤ W3 / W1 ≤ 40%. For example, W3 / W1 can be located in multiple intervals such as 30% ≤ W3 / W1 ≤ 35%, 25% ≤ W3 / W1 ≤ 35%, and 35% ≤ W3 / W1 ≤ 40%. Specifically, W3 / W1 = 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%, including but not limited to the values ​​listed above. Other values ​​between any two of the above are still applicable. It is understood that the minimum distance between the first outer peripheral surface 101 of the first connecting portion 21 and the edge of the cover plate 10 refers to the minimum distance from any point on the first outer peripheral surface 101 of the first connecting portion 21 to the plane containing the edge of the cover plate 10 along the width direction of the cover plate 10. With this configuration, while ensuring that the first connecting portion 21 has sufficient welding area, sufficient space can be reserved in the width direction of the cover plate 10 for the welding area of ​​the second connecting portion 22 and for the outer sheath of the housing to be folded from the edge of the cover plate 10 to the edge of the first insulating member 30.

[0181] Understandably, the first electrical connection portion 212 may also omit the first stepped surface 104. When the first electrical connection portion 212 does not have the first stepped surface 104, the dimension of the first electrical connection portion 212 along the width direction of the cover plate 10 is equal to the dimension of the first electrical connection surface 102 along the width direction of the cover plate 10. That is, the entire surface of the first electrical connection portion 212 away from the base portion 211 is used as the first electrical connection surface 102. In the embodiments shown in Figures 8 and 12, although the cross-sectional area of ​​the base portion 211 is larger than the cross-sectional area of ​​the first electrical connection portion 212, the maximum width of the first electrical connection portion 212 in the width direction of the cover plate 10 can be equal to the maximum width W2 of the first connection portion 21.

[0182] As one embodiment of the first connecting portion 21 of the pole post 20, as shown in FIG8, along the thickness direction of the cover plate 10, the orthographic projection of the first connecting portion 21 on the cover plate 10 does not overlap with the first through hole 13, that is, the orthographic projection of the first connecting portion 21 on the cover plate 10 does not fall into the first through hole 13. At this time, along the width direction of the cover plate 10, the minimum distance between the first outer peripheral surface 101 and the hole wall of the first through hole 13 is W5, which satisfies: 0≤W5≤10mm. For example, W5 is located in multiple intervals such as 0≤W5≤6mm, 0≤W5≤4mm, etc. Specifically, W5 = 0mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, including but not limited to the values ​​listed above, and other values ​​between any two of the above still apply. It can be understood that the first outer peripheral surface 101 can be aligned with the hole wall of the first through hole 13, and the hole wall of the first through hole 13 can also protrude from the first outer peripheral surface 101. It is understandable that the minimum distance between the first outer peripheral surface 101 and the wall of the first through hole 13 refers to the minimum value among the distances from any point on the first outer peripheral surface 101 to any point on the wall of the first through hole 13 along the width direction of the cover plate 10. This setting ensures that the first connecting part 21 has sufficient welding area, while reducing the size of the first connecting part 21 in the width direction of the pole post 20.

[0183] As another embodiment of the first connecting portion 21 of the pole post 20, as shown in FIG16, along the thickness direction of the cover plate 10, the orthographic projection of the first connecting portion 21 on the cover plate 10 partially overlaps with the first through hole 13, that is, the partial orthographic projection of the first connecting portion 21 on the cover plate 10 falls into the first through hole 13. It can be understood that the first outer peripheral surface 101 of the first connecting portion 21 protrudes from the hole wall of the first through hole 13. At this time, along the width direction of the cover plate 10, the distance between the first outer peripheral surface 101 and the hole wall of the first through hole 13 is W5, which satisfies: 0≤W5≤10mm. For example, W5 can be located in multiple intervals such as 0≤W5≤6mm, 0≤W5≤4mm, etc. Specifically, W5 = 0mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, including but not limited to the values ​​listed above, and other values ​​between any two of the above still apply. This configuration ensures that the first connecting part 21 has sufficient welding area, while reducing the size of the first connecting part 21 in the width direction of the pole post 20 to fit the cover plate 10 with a smaller width.

[0184] As one embodiment of the pole post 20, referring to Figures 8, 9, 10, 11, and 12, the second connecting portion 22 of the pole post 20 has a first groove 24. Along the thickness direction of the cover plate 10, the opening of the first groove 24 is formed on the surface of the second connecting portion 22 near the first connecting portion 21, that is, the opening of the first groove 24 is located on the side of the cover plate 10 with the first surface 11. The opening of the first groove 24 can be located outside the first surface 11, that is, higher than the first surface 11. The second connecting portion 22 forms a second electrical connection portion 240 on the bottom wall of the first groove 24. The second electrical connection portion 240 is connected to the tab 301, thereby making the second connecting portion 22 form a hollow structure, reducing the overall weight of the pole post 20 and saving materials. It should be noted that the groove depth of the first groove 24 needs to consider the welding penetration depth of the second electrical connection portion 240 and the tab 301, the material utilization rate, and the space utilization rate inside the shell. While saving materials, the welding quality of both needs to be guaranteed.

[0185] Referring to Figure 8, along the thickness direction of the cover plate 10, the bottom surface of the first groove 24 is located between the first surface 11 and the second surface 12, thereby ensuring the welding depth between the second electrical connection part 240 and the tab 301, while saving the material of the electrode post 20 and improving the space utilization rate inside the battery cell.

[0186] Referring to Figures 9, 10, 11, and 12, in this embodiment, the second connecting portion 22 of the pole post 20 is provided with a flange 23 around the opening of the first groove 24. Along the thickness direction of the cover plate 10, the flange 23 is located on the side of the cover plate 10 with the first surface 11. It can be understood that the flange 23 is a bent structure extending around the opening of the first groove 24 in a direction away from the central axis of the first groove 24. Providing the flange 23 around the opening of the first groove 24 facilitates the upper and lower dies pressing down on the pole post 20 through the flange 23 during the stamping process of the second connecting portion 22 of the pole post 20, and also facilitates the downward drawing of the two second connecting portions 22 to form the first groove 24.

[0187] In some embodiments, referring to Figure 8, the minimum distance between the sidewall of the flange 23 and the edge of the cover plate 10 along the width direction of the cover plate 10 is W4, satisfying: 5% ≤ W4 / W1 ≤ 20%. For example, W4 / W1 can be located within multiple intervals such as 5% ≤ W4 / W1 ≤ 15%, 10% ≤ W4 / W1 ≤ 15%, 12% ≤ W4 / W1 ≤ 20%, etc. Specifically, W4 / W1 = 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, including but not limited to the values ​​listed above, and other values ​​between any two of the above still apply. It is understood that the minimum distance between the sidewall of the flange 23 and the edge of the cover plate 10 refers to the minimum value of the distance from any point on the sidewall of the flange 23 to the plane containing the edge of the cover plate 10 along the width direction of the cover plate 10. When the ratio of W4 / W1 is less than 5%, the sidewall of the flange 23 is too close to the edge of the cover plate 10, which will affect the size of the outer film of the housing folded at the edge of the cover plate to the edge of the first insulating member 30. When the ratio of W4 / W1 is greater than 20%, the sidewall of the flange 23 will be far from the edge of the cover plate 10, which will compress the size of the second connecting part 22 and the first connecting part 21 along the width direction of the cover plate 10, thereby reducing the weldable area of ​​the second connecting part 22 and the tab 301 as well as the weldable area of ​​the first connecting part 21 and the electrical connector.

[0188] In some embodiments, the minimum distance between the sidewall of the flange 23 and the edge of the cover plate 10 is W4, satisfying: 3mm≤W4≤10mm. For example, W4 can be within multiple ranges such as 5mm≤W4≤8mm, 3mm≤W4≤6mm, 6mm≤W4≤10mm, 7mm≤W4≤10mm, etc. Specifically, W4 = 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm, including but not limited to the values ​​listed above, and other values ​​between any two of the above still apply. When W4 is less than 3mm, the side wall of the flange 23 is too close to the edge of the cover plate 10, which will further affect the size of the outer shell film at the edge of the cover plate to the edge of the first insulating member 30; when W4 is greater than 10mm, the size of the second connecting part 22 and the first connecting part 21 along the width direction of the cover plate 10 is compressed, thereby reducing the weldable area of ​​the second connecting part 22 and the tab 301 as well as the weldable area of ​​the first connecting part 21 and the electrical connector.

[0189] In some embodiments, referring to FIG8, at least a portion of the orthographic projection of the flange 23 falls on the cover plate 10 along the thickness direction of the cover plate 10, that is, on a virtual plane perpendicular to the thickness direction of the cover plate 10, the orthographic projection of the flange 23 overlaps with the orthographic projection of the cover plate 10. It is understood that, along the direction perpendicular to the thickness direction of the cover plate 10, the edge of the flange 23 protrudes beyond the wall of the first through hole 13. With this configuration, if necessary, a sealing ring can be installed on the side of the flange 23 facing the interior of the housing. The sealing ring can be pressed under the flange 23 to further seal the first through hole 13 and the second connecting portion 22.

[0190] Referring to Figures 9, 10, 11, and 12, the flanged portion 23 can be directly connected to the first outer peripheral surface 101 of the base portion 211 of the first connecting portion 21, thereby eliminating the transition portion between the first connecting portion 21 and the second connecting portion 22. Compared with the prior art, when the maximum dimension of the pole post 20 along the width direction of the cover plate 10 is fixed, more space is provided for the weldable area of ​​the first connecting portion 21 and the weldable area of ​​the second connecting portion 22.

[0191] Referring to Figures 10 and 12, the upper surface of the flange 23 is flush with the upper surface of the base 211, and the lower surface of the flange 23 is also flush with the lower surface of the base 211. The upper surface of the flange 23 can be the surface facing outwards from the housing, and the upper surface of the base 211 is the surface facing outwards from the housing, i.e., the third step surface 105. The lower surface of the flange 23 is the surface facing inwards from the housing. The lower surface of the base 211 is the surface facing inwards from the housing, i.e., the fifth surface 103. Since the upper and lower surfaces of the flange 23 and the base 211 are parallel, the thickness of the punched surface is uniform throughout when the pole post 20 is processed, there is no height difference in the punched surface, and the outermost contour of the pole post 20 can be punched out in the final step of stamping, resulting in fewer punching burrs.

[0192] The lower surface of the flange 23 is flush with the lower surface of the base 211, which also makes it easier to press it down from below during stamping. The upper and lower dies match, making it easier to draw out the first groove 24.

[0193] Referring to Figures 8, 9, and 10, when the electrode post 20 is a negative electrode post, the second connecting portion 22 includes a first metal layer 221 and a second metal layer 222. The first metal layer 221 and the second metal layer 222 are stacked along the thickness direction of the second connecting portion 22, with the second metal layer 222 located on the side of the first metal layer 221 facing the interior of the housing. The first metal layer 221 can be connected to the first connecting portion 21 and is made of the same material. The second metal layer 222 covers the outside of the first metal layer 221. The second metal layer 222 directly contacts the negative electrode tab for welding. More specifically, in this embodiment, the first metal layer 221 is an aluminum layer, and the second metal layer 222 is a copper layer. Since the material of the negative electrode tab of the electrode assembly is generally also copper, the second metal layer 222 is made of the same material as the negative electrode tab to improve the welding effect between the negative electrode post and the negative electrode tab.

[0194] In some embodiments, at least a portion of the interface between the first metal layer 221 and the second metal layer 222 intersects with the sidewall surface of the flange portion 23. It is understood that the sidewall surface of the flange portion 23 refers to its circumferential side surface. Since the flange portion 23 is located on the side of the cover plate 10 having the first surface 11, the interface between the first metal layer 221 and the second metal layer 222 can be located on the outside of the cover plate 10, preventing the first metal layer 221, which is an aluminum layer, from contacting the electrolyte inside the casing and corroding, thereby affecting the safety performance of the battery cell.

[0195] As another embodiment of the pole post 20, referring to Figures 17, 18, or 31, the second connecting portion 22 is a plate-like structure, and the second connecting portion 22 of the pole post 20 does not have the first groove 24. It should be noted that the plate-like structure of the second connecting portion 22 can be understood as maintaining a consistent thickness along both the length direction (i.e., the length direction of the cover plate 10) and the width direction (i.e., the width direction of the cover plate 10). This makes processing more convenient, provides more space for the welding area of ​​the first connecting portion 21, and further reduces the total width of the pole post 20. In other words, when the total width of the pole post 20 is constant, it can increase the weldable area of ​​either the first connecting portion 21 or the weldable area of ​​the second connecting portion 22. The width direction of the pole post 20 is the same as the width direction of the cover plate 10.

[0196] Please refer to Figures 16, 17, 18 or 31. Along the thickness direction of the cover plate 10, the second connecting part 22 has a third surface 202. The third surface 202 is the surface of the second connecting part 22 facing the outside of the housing, that is, the surface close to the first connecting part 21, and the third surface 202 has a continuous planar structure.

[0197] In some embodiments, as shown in FIG16, the third surface 202 is located between the first surface 11 and the second surface 12. This arrangement ensures the welding penetration depth between the second connecting portion 22 and the tab 301, while saving material of the electrode post and improving the space utilization rate inside the battery cell.

[0198] In some other embodiments, as shown in FIG30, the third surface 202 is flush with the first surface 11 of the cover plate 10. With this arrangement, when the first insulating component 30 is injection molded, the third surface 202 and the first surface 11 are flush, resulting in more uniform force distribution during injection molding, a longer sealing path, and easier injection molding. After injection molding, the first insulating component 30 will also experience more uniform force distribution.

[0199] In some other embodiments, the third surface 202 may also protrude beyond the first surface 11 of the cover plate 10. That is, in the battery cell, the third surface 202 of the second connecting portion 22 facing the outside of the housing is higher than the first surface 11 of the cover plate 10 facing the outside of the housing.

[0200] As shown in Figures 17, 18, or 31, the outer contour of the second connecting portion 22 forms a second outer peripheral surface 201. The second outer peripheral surface 201 is disposed around the third surface 202 and extends in a direction perpendicular to the third surface 202. The extension direction of the second outer peripheral surface 201 of the second connecting portion 22 can be the same as the extension direction of the first outer peripheral surface 101 of the first connecting portion 21, thereby reducing the distance between the first connecting portion 21 and the second connecting portion 22, reducing the dimension in the width direction of the pole post 20, or, when the total width of the pole post 20 is constant, increasing the weldable area of ​​the first connecting portion 21 or the weldable area of ​​the second connecting portion 22. In addition, it also helps to reduce the forming difficulty of the second connecting portion 22.

[0201] As shown in Figures 11, 12, 18, or 31, in some embodiments, the second connecting portion 22 includes a third sub-portion 205 and a fourth sub-portion 206. Along the thickness direction of the cover plate 10, and on a plane perpendicular to the thickness direction of the cover plate 10, the orthographic projection of the fourth sub-portion 206 falls within the orthographic projection range of the third sub-portion 205. It is understood that the cross-sectional area of ​​the fourth sub-portion 206 is smaller than that of the third sub-portion 205. A second stepped surface 203 connects the sidewall of the fourth sub-portion 206 and the sidewall of the third sub-portion 205. The end surface of the fourth sub-portion 206 away from the third sub-portion 205 is a second electrical connection surface 204. The second connecting portion 22 has a second stepped surface 203 and a second electrical connection surface 204 on the side passing through the first through hole 13. The second electrical connection surface 204 protrudes from the second stepped surface 203, meaning the second stepped surface 203 is positioned closer to the electrode assembly 300 than the second electrical connection surface 204. The second electrical connection surface 204 is used to connect with the tab 301. The penetration depth of the tab 301 and the second electrical connection surface 204 extends from the tab 301 through the second electrical connection surface 204 toward the interior of the second connection portion 22. The second electrical connection surface 204 protrudes from the second stepped surface 203, which facilitates direct welding of the tab 301 to the second electrical connection surface 204, avoids interference and damage to the tab 301 from other components, and improves the safety of the battery cell. Understandably, the second connection portion 22 may also be without the second stepped surface 203. When the second connection portion 22 is not provided with the second stepped surface 203, the entire end face of the second connection portion 22 passing through the first through hole 13 serves as the second electrical connection surface 204.

[0202] As one embodiment of the terminal post 20, referring to Figures 17, 18, or 31, the terminal post 20 further includes a transition portion 25. Along the width direction of the cover plate 10, the transition portion 25 connects between the first connecting portion 21 and the second connecting portion 22. In this embodiment, by bending the transition portion 25, the first connecting portion 21, the second connecting portion 22, and the transition portion 25 can be directly formed, making processing convenient. At the same time, since the transition portion 25 connects between the first connecting portion 21 and the second connecting portion 22 along the width direction of the cover plate 10, the occupied size in the width direction of the terminal post 20 can be reduced, leaving more space for the welding surface width of the first connecting portion 21 and the welding surface width of the second connecting portion 22, thereby reducing the overall size of the terminal post 20 in the width direction, making it suitable for battery cells with limited space in the top cover assembly design. Furthermore, by reducing the dimension of the transition portion 25 along the length of the cover plate 10 or thinning the thickness of the transition portion 25, the transition portion 25 can also function as a fuse. A fuse is a structural component that melts preferentially over the first connection portion 21 and the second connection portion 22 when thermal runaway occurs in a battery cell. This allows the circuit to be promptly disconnected via the transition portion 25 in the event of thermal runaway within the battery cell.

[0203] As shown in Figure 16 or Figure 30, at least a portion of the transition portion 25 is projected into the first through hole 13 along the thickness direction of the cover plate 10. It can be understood that since at least a portion of the transition portion 25 is accommodated within the first through hole 13, the transition portion 25 does not occupy additional width in the width direction of the cover plate 10, thus reducing the total width of the pole post 20. In other words, when the total width of the pole post 20 is constant, it can increase the weldable area of ​​the first connecting portion 21 or the weldable area of ​​the second connecting portion 22.

[0204] Specifically, as shown in Figure 23, the first through hole 13 of the cover plate 10 has a notch 16 for accommodating the transition portion 25. The notch 16 can refer to an opening on the wall of the first through hole 13 on the side opposite to the edge of the cover plate 10, corresponding to the position of the transition portion 25. In some embodiments, the notch 16 is provided on the support portion 15. This allows the portion where the projection of the transition portion 25 overlaps with that of the first through hole 13 to be accommodated in the notch 16, preventing interference from the wall of the first through hole 13 with the transition portion 25.

[0205] To ensure that the transition portion 25 melts preferentially before the first connecting portion 21 and the second connecting portion 22 in the event of thermal runaway in a single battery cell, as shown in Figure 17 or Figure 28, the length of the transition portion 25 is less than the length of the first connecting portion 21 and less than the length of the second connecting portion 22 along the length direction of the cover plate 10. This makes the current-carrying area of ​​the transition portion 25 smaller than that of the first connecting portion 21 and less than that of the second connecting portion 22. The current-carrying area of ​​the transition portion 25 refers to the surface area of ​​the transition portion 25 perpendicular to the current flow direction, i.e., the minimum cross-sectional area of ​​the transition portion 25. The current-carrying areas of the first connecting portion 21 and the second connecting portion 22 refer to the surface areas of the first connecting portion 21 and the second connecting portion 22 perpendicular to the current flow direction, i.e., the minimum cross-sectional areas of the first connecting portion 21 and the second connecting portion 22. Thus, in actual use, when a circuit malfunction occurs, the smaller current-carrying area of ​​the transition portion 25 causes a faster temperature rise at the transition portion 25, allowing it to melt quickly and promptly disconnect the circuit, greatly improving battery safety.

[0206] It is understandable that the transition portion 25 can also reduce the current-carrying area by slotting, opening, and / or thinning, ensuring that the circuit can be cut off in time when the circuit is abnormal. The thinning structure can be a general reduction in the thickness of the transition portion 25, or a groove structure formed in a part of the transition portion 25 and partially thinning the transition portion 25.

[0207] To further reduce the size of the transition portion 25 in the width direction of the cover plate 10, as one embodiment of the transition portion 25, as shown in FIG18, one end of the transition portion 25 is connected to the side wall of the second connecting portion 22, and the other end of the transition portion 25 is connected to the first outer peripheral surface 101 of the first connecting portion 21. The transition portion 25 includes a first arc segment 251, a first straight segment 252, and a second arc segment 253. The first arc segment 251 may be a transition segment connecting the first straight segment 252 to the side wall of the second connecting portion 22, and the first straight segment 252 is parallel to the side wall of the second connecting portion 22. The second arc segment 253 may be a transition segment connecting the first straight segment 252 to the first outer peripheral surface 101 of the first connecting portion 21, thereby reducing the size of the transition portion 25 in the width direction of the cover plate 10.

[0208] As another embodiment of the transition portion 25, as shown in FIG31, one end of the transition portion 25 is connected to the third surface 202 of the second connecting portion 22, and the other end of the transition portion 25 is connected to the first outer peripheral surface 101 of the first connecting portion 21. In this embodiment, the transition portion 25 may include at least a first arc segment 251 and a first straight segment 252, wherein the first arc segment 251 may be a transition segment connecting the first straight segment 252 and the third surface 202 of the second connecting portion 22, and the first straight segment 252 is parallel to the third surface 202, thereby reducing the size of the transition portion 25 in the width direction of the cover plate 10.

[0209] As one embodiment of the cover plate 10, referring to Figure 22, the first surface 11 of the cover plate 10 is provided with a second groove 14, which is recessed from the first surface 11 towards the second surface 12. It is understood that the second groove 14 is located on the surface of the cover plate 10 facing the outside of the housing. Since the number of first through holes 13 can be consistent with the number of second connecting parts 22, each second connecting part 22 is respectively inserted into a first through hole 13. At least two second connecting parts 22 are respectively inserted into at least two first through holes 13. Each first through hole 13 penetrates the bottom wall of the second groove 14 along the thickness direction of the cover plate 10. That is, at least two first through holes 13 are disposed in the second groove 14. For example, in this embodiment, two first through holes 13 are disposed in the second groove 14, with a gap between the hole wall of the first through hole 13 and the groove sidewall of the second groove 14, that is, the hole wall of the first through hole 13 and the groove sidewall of the second groove 14 are not aligned.

[0210] The second groove 14 reduces the distance between the first electrical connection surface 102 of the terminal post 20 facing the outside of the housing and the first surface 11 of the cover plate 10, improving the battery space utilization. Furthermore, it also reduces the dimension of the terminal post 20 along the thickness direction of the cover plate 10, i.e., reduces the height difference between the first electrical connection surface 102 of the terminal post 20 facing the outside of the housing and the second electrical connection surface 204 facing the inside of the housing, which helps to reduce the molding difficulty of the terminal post 20.

[0211] In some embodiments, as shown in FIG8, the groove depth of the second groove 14 along the thickness direction of the cover plate 10 is T1, satisfying: 0.3mm≤T1≤1.5mm. For example, T1 can be located within multiple intervals such as 0.3mm≤T1≤1.2mm, 0.3mm≤T1≤0.8mm, 0.4mm≤T1≤1mm, and 0.4mm≤T1≤0.6mm. Specifically, T1 = 0.3mm, 0.4mm, 0.5mm, 0.7mm, 0.8mm, 0.9mm, 1.1mm, 1.3mm, or 1.5mm, including but not limited to the listed values, and other values ​​between any two of the above still apply. The groove depth of the second groove 14 can be understood as the distance between the bottom wall of the second groove 14 and the first surface 11 of the cover plate 10. Through the above configuration, on the one hand, the distance between the first electrical connection surface 102 of the electrode post 20 facing the outside of the housing and the first surface 11 of the cover plate 10 can be reduced, and on the other hand, the bottom wall of the second groove 14 can provide some support for the electrode post 20. When the groove depth T1 of the second groove 14 is less than 0.3mm, the groove depth of the second groove 14 is relatively shallow, which will result in a larger distance between the first electrical connection surface 102 of the electrode post 20 facing the outside of the housing and the first surface 11 of the cover plate 10, and the height of the electrode post 20 will be relatively high, which will occupy more height space of the battery and increase the difficulty of molding the electrode post 20. When the groove depth T1 of the second groove 14 is greater than 1.5mm, the groove depth T1 of the second groove 14 is relatively large, which will result in a thinner bottom of the second groove 14, which is not conducive to the strength of the cover plate 10 and the stable fixation of the electrode post 20.

[0212] In some embodiments, as shown in FIG8, along the thickness direction of the cover plate 10, the groove depth of the second groove 14 is T1, and the thickness of the cover plate 10 is T2, satisfying: 10% ≤ T1 / T2 ≤ 80%. For example, T1 / T2 can be located within multiple intervals such as 10% ≤ T1 / T2 ≤ 70%, 10% ≤ T1 / T2 ≤ 50%, 10% ≤ T1 / T2 ≤ 40%, 10% ≤ T1 / T2 ≤ 30%, 20% ≤ T1 / T2 ≤ 30%, etc. Specifically, T1 / T2 = 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, including but not limited to the values ​​listed above, and other values ​​between any two of the above still apply. The above settings allow the groove depth of the second groove 14 and the thickness of the cover plate 10 to be set within a suitable ratio range, reducing the distance between the first electrical connection surface 102 of the electrode post 20 facing the outside of the housing and the first surface 11 of the cover plate 10, improving the space utilization of the battery, reducing the height of the electrode post 20, reducing the molding difficulty of the electrode post 20, and ensuring the stability of the electrode post 20 after assembly.

[0213] As shown in Figure 8, the distance W6 between the fifth surface 103 of the first connecting part 21 and the bottom wall of the second groove 14 satisfies: 0.5mm ≤ W6 ≤ 1.2mm. For example, W6 can be located in multiple ranges such as 0.5mm ≤ W6 ≤ 1mm, 0.6mm ≤ W6 ≤ 0.9mm, etc. Specifically, W6 = 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, or 1.2mm, etc., including but not limited to the values ​​listed above. Other values ​​between any two of the above are still applicable. This arrangement allows for a gap between the fifth surface 103 of the first connecting part 21 facing the inside of the housing and the bottom of the second groove 14. This gap is used to fill part of the structure of the first insulating member 30 to insulate the first connecting part 21 and the cover plate 10. The thickness of the portion of the first insulating member 30 filling this gap should not be too thick, as this would occupy height space, nor should it be too thin, as this would cause the filled first insulating member 30 to easily crack and shrink.

[0214] As another embodiment of the cover plate, referring to Figure 23, the cover plate 10 has a through hole along its thickness direction, and a support portion 15 is provided in the through hole. The two ends of the support portion 15, which are arranged opposite each other along its longitudinal direction, are respectively connected to the two side walls of the through hole, which are arranged opposite each other along the length direction of the cover plate 10, dividing the through hole into two first through holes 13 spaced apart along the width direction of the cover plate 10. The support portion 15 can be used to support the first connecting portion 21 of the first insulating member 30 and the electrode post 20. The surface of the support portion 15 facing the outside of the housing 200 is lower than the upper surface of the cover plate 10. The upper surface of the cover plate 10 refers to the side surface of the cover plate 10 away from the interior of the housing 200. This arrangement reduces the distance between the welding surface of the electrode post 20 and the electrical connector and the upper surface of the cover plate 10, improving the space utilization rate within the battery. Meanwhile, the support part 15 allows the second connecting part 22 of the pole post 20 to be closer to the inside of the housing 200, which can reduce the height of the pole post 20 and thus reduce the processing difficulty of the pole post 20.

[0215] As shown in Figure 16, along the thickness direction of the cover plate 10, the support part 15 has a sixth surface 152 that is disposed opposite to the fourth surface 151. The sixth surface 152 faces the inside of the housing and can be flush with the second surface 12 of the cover plate 10 to facilitate the processing of the cover plate 10.

[0216] In some embodiments, as shown in FIG16, the distance between the fourth surface 151 of the support portion 15 and the first surface 11 is T3, satisfying 0.3mm≤T3≤1.5mm. For example, T3 can be located within multiple intervals such as 0.3mm≤T3≤1.2mm, 0.3mm≤T3≤0.8mm, 0.4mm≤T3≤1mm, and 0.4mm≤T3≤0.6mm. Specifically, T3 = 0.3mm, 0.4mm, 0.5mm, 0.7mm, 0.8mm, 0.9mm, 1.1mm, 1.3mm, or 1.5mm, including but not limited to the values ​​listed above. Other values ​​between any two of the above are still applicable. This configuration can reduce the distance between the first electrical connection surface 102 of the pole post 20 facing the outside of the housing and the first surface 11 of the cover plate 10, while the support portion 15 can provide certain support for the pole post 20. When T3 is less than 0.3mm, the distance between the fourth surface 151 and the first surface 11 of the support portion 15 is too small, resulting in a larger distance between the first electrical connection surface 102 of the terminal post 20 and the first surface 11 of the cover plate 10. This leads to a higher height for the terminal post 20, increasing the difficulty of molding the terminal post 20 and occupying more height space in the battery. When T3 is greater than 1.5mm, the distance between the fourth surface 151 and the first surface 11 of the support portion 15 is too large, resulting in a thinner support portion 15. This is detrimental to the strength of the cover plate 10 and the stable fixation of the terminal post 20.

[0217] Along the thickness direction of the cover plate 10, the relationship between the thickness T2 of the cover plate 10 and the distance T3 between the fourth surface 151 and the first surface 11 of the support portion 15 satisfies: 10% ≤ T3 / T2 ≤ 80%. For example, T3 / T2 can be located within multiple intervals such as 10% ≤ T3 / T2 ≤ 70%, 10% ≤ T3 / T2 ≤ 50%, 10% ≤ T3 / T2 ≤ 40%, 10% ≤ T3 / T2 ≤ 30%, 20% ≤ T3 / T2 ≤ 30%, etc. Specifically, T3 / T2 = 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%, including but not limited to the values ​​listed above. Other values ​​between any two of the above still apply. By setting the above parameters, the thickness of the support 15 and the thickness of the cover plate 10 are set in a suitable ratio range, thereby reducing the distance between the first electrical connection surface 102 of the terminal post 20 facing the outside of the housing and the first surface 11 of the cover plate 10, improving the space utilization of the battery, reducing the height of the terminal post 20, thereby reducing the molding difficulty of the terminal post 20, and ensuring the stability of the terminal post 20 after assembly.

[0218] In some embodiments, as shown in FIG8 or FIG18, the distance between the fifth surface 103 of the first connecting portion 21 and the fourth surface 151 of the support portion 15 is W6, satisfying: 0.5mm≤W6≤1.2mm. For example, W6 can be located in multiple ranges such as 0.5mm≤W6≤1mm, 0.6mm≤W6≤0.9mm, etc. Specifically, W6 = 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, or 1.2mm, etc., including but not limited to the values ​​listed above, and other values ​​between any two of the above still apply. This arrangement allows for a gap between the fifth surface 103 of the first connecting portion 21 facing the interior of the housing and the fourth surface 151 of the support portion 15. This gap is used to fill part of the structure of the first insulating member 30 to insulate the first connecting portion 21 and the cover plate 10. The thickness of the portion of the first insulating element 30 filling the gap should not be too thick, as this would occupy too much height space, nor should it be too thin, as this would cause the portion of the first insulating element 30 to easily crack and shrink.

[0219] Referring to Figures 6 and 28, the cover plate 10 may also be provided with a first insulating element 30. The first insulating element 30 is fixedly connected to the pole post 20 and the cover plate 10, and is used to fix the pole post 20 on the cover plate 10 and isolate the pole post 20 and the cover plate 10 to reduce the risk of short circuit. For example, the first insulating element 30 may be a plastic material, such as PP, PE, PPS, etc.

[0220] In this embodiment, referring to Figures 8, 13, 19, 28, and 30, the first insulating member 30 includes a first insulating portion 31, a second insulating portion 32, and a third insulating portion 33 connected together. The first insulating portion 31 is disposed on the side of the cover plate 10 having the second surface 12. It is understood that the first insulating portion 31 is disposed between the side of the cover plate 10 having the second surface 12 and the second connecting portion 22, forming an insulation, which can prevent the second connecting portion 22 from contacting and electrically connecting with the cover plate 10. Along the thickness direction of the cover plate 10, at least a portion of the orthographic projection of the first insulating portion 31 falls on the cover plate 10, that is, on a virtual plane perpendicular to the thickness direction of the cover plate 10, the orthographic projection of the first insulating portion 31 overlaps with the orthographic projection of the cover plate 10. It is understood that at least a portion of the orthographic projection of the first insulating portion 31 falls on the solid structure of the cover plate 10, which does not include the first through hole 13. That is, at least a portion of the orthographic projection of the first insulating part 31 on a dummy plane overlaps with the orthographic projection of the cover plate 10 on the dummy plane, so that at least a portion of the first insulating part 31 bends toward the inner side of the cover plate 10 below the hole wall of the first through hole 13 and connects or snaps with the lower surface of the cover plate 10, so as to improve the fixing effect of the electrode post through the first insulating part 31, and the lower surface of the insulating cover plate 10 and the electrode post 20 at the same time play a sealing role to prevent electrolyte from leaking out from the first through hole 13.

[0221] The second insulating part 32 is disposed between the wall of the first through hole 13 and the second connecting part 22 of the electrode post 20, so as to connect the second connecting part 22 and the wall of the first through hole 13 through the second insulating part 32 and form insulation, and at the same time, it can play a sealing role to prevent electrolyte from leaking out of the first through hole 13. The second insulating part 32 can be in the form of a ring structure, with one end of the second insulating part 32 facing the inside of the housing connected to the first insulating part 31, and the other end of the second insulating part 32 facing the outside of the housing connected to the third insulating part 33.

[0222] The third insulating portion 33 is disposed on the side of the cover plate 10 having the first surface 11, that is, the third insulating portion 33 is disposed on the outer side of the cover plate 10. It can be understood that the third insulating portion 33 covers the pole portion located on the outer side of the cover plate 10 to insulate the pole portion located on the first surface 11 of the cover plate 10 and the cover plate 10. Simultaneously, the third insulating portion 33 also serves a sealing function. The pole portion located on the first surface 11 of the cover plate 10 includes a portion of the structure of the first connecting portion 21 and the second connecting portion 22. Along the thickness direction of the cover plate 10, at least a portion of the orthographic projection of the third insulating portion 33 falls on the cover plate 10, that is, on a virtual plane perpendicular to the thickness direction of the cover plate 10, the orthographic projection of the third insulating portion 33 overlaps with the orthographic projection of the cover plate 10. It can be understood that the outer contour edge of the third insulating portion 33 protrudes from the wall of the first through hole 13.

[0223] First, the first insulating part 31 and the second insulating part 32 are connected as a whole, forming an L-shape, which allows them to interlock with the cover plate 10, thereby improving the fixing effect on the terminal post 20. Furthermore, when at least a portion of the orthographic projection of the third insulating part 33 falls on the orthographic projection of the cover plate 10, i.e., when the orthographic projections of the third insulating part 33 and the cover plate 10 overlap, the first insulating part 31 and the third insulating part 33 can jointly clamp the cover plate 10 from both sides in the thickness direction, further improving the fixing effect on the terminal post 20. Secondly, the sealing ring structure in the top cover assembly of related technologies can be eliminated, thus eliminating the size requirement of the sealing ring in the width direction of the cover plate 10. Therefore, only the dimensions of the outer casing film folded at the edge of the cover plate to the edge of the first insulating member 30, the dimensions of the two second connecting parts 22, and the dimensions of the first connecting part 21 need to be considered. Even for battery cells with small thicknesses and limited cover plate width, the weldable area of ​​the first connecting part 21 and the second connecting part 22 can be guaranteed, thus not affecting the battery's charging and discharging performance and safety performance. Finally, the second insulating part 32 is inserted into the first through hole 13, which can prevent the electrolyte from leaking out of the first through hole 13 due to compression failure of the sealing ring during long-term use. Furthermore, the first insulating part 31, the second insulating part 32 and the third insulating part 33 are connected as one unit, which can increase the sealing path for sealing the hole wall of the first through hole 13, further preventing the electrolyte from leaking out of the first through hole 13.

[0224] In this embodiment, the first insulating portion 31, the second insulating portion 32, and the third insulating portion 33 of the first insulating member 30 are integrally formed. Furthermore, the first insulating portion 31, the second insulating portion 32, and the third insulating portion 33 are integrally nano-injection molded. Nano-injection molding is a process technology that tightly bonds metal and plastic. By integrally nano-injection molding the first insulating portion 31, the second insulating portion 32, and the third insulating portion 33, the sealing performance of the battery cell can be greatly improved, thus further ensuring that the sealing ring can be eliminated in this application. Of course, in some other embodiments, the first insulating portion 31, the second insulating portion 32, and the third insulating portion 33 can also be formed separately first, and then connected by bonding, hot melting, or other methods. Of course, in other embodiments, only the second insulating portion 32 can be nano-injection molded. Alternatively, the first insulating portion 31 and the second insulating portion 32 can also be nano-injection molded.

[0225] Specifically, the surfaces of the cover plate 10 that contact the first insulating part 31 and the second insulating part 32 are provided with first nanopores, and at least a portion of the first insulating part 31 and the second insulating part 32 are embedded in the first nanopores; this can increase the bonding force and sealing performance between the first insulating part 31 and the second insulating part 32 and the cover plate 10. During the manufacturing process, nanopore structures can be formed on the second surface 12 of the cover plate 10 and the hole walls of the first through hole 13 by chemical etching, thereby increasing the contact surface area of ​​the first insulating part 31, the second insulating part 32 and the cover plate 10, and improving the bonding force and sealing performance.

[0226] In some embodiments, the surfaces of the electrode post 20 that contact the first insulating portion 31 and the second insulating portion 32 are provided with second nanopores, and the first insulating portion 31 and the second insulating portion 32 are at least partially embedded in the second nanopores. During the manufacturing process, a nanopore structure can be formed on the circumferential side surface of the second connecting portion 22 of the electrode post 20 by chemical etching to increase the contact surface area with the first insulating portion 31 and the second insulating portion 32, thereby improving the bonding force and sealing performance between the first insulating portion 31 and the second insulating portion 32 and the electrode post 20.

[0227] In some embodiments, the surface of the cover plate 10 in contact with the third insulating portion 33 is provided with a third nanopore, and at least a portion of the third insulating portion 33 is embedded in the third nanopore. During the manufacturing process, a nanopore structure can be formed on the first surface 11 of the cover plate 10, the bottom of the second groove 14, or the fourth surface 151 of the support portion 15 by chemical etching, thereby increasing the contact surface area between the third insulating portion 33 and the cover plate 10 and improving the bonding force and sealing performance between the third insulating portion 33 and the cover plate 10.

[0228] In some embodiments, the surface of the pole post 20 in contact with the third insulating portion 33 is provided with a fourth nanopore, and at least a portion of the third insulating portion 33 is embedded in the fourth nanopore. During the manufacturing process, nanopore structures can be formed by chemical etching on the fifth surface 103 of the first connecting portion 21, the bottom and wall surfaces of the first groove 24 of the second connecting portion 22, the upper and lower surfaces of the flange portion 23 of the second connecting portion 22, and the circumferential side surfaces. Alternatively, in some other embodiments, nanopore structures can be formed by chemical etching on the fifth surface 103 of the first connecting portion 21, the upper and lower surfaces of the transition portion 25, and the third surface 202 of the second connecting portion 22, thereby increasing the contact surface area between the third insulating portion 33 and the pole post 20, and improving the bonding force and sealing performance between the third insulating portion 33 and the pole post 20.

[0229] In some embodiments, as shown in FIG8, FIG16, or FIG30, the surface of the first insulating portion 31 facing the interior of the housing is planar. In some embodiments, the surface of the first insulating portion 31 facing the interior of the housing (i.e., the surface facing away from the cover plate 10) is flush with the second stepped surface 203 of the second connecting portion 22, to avoid the first insulating portion 31 affecting the welding between the second electrical connection surface 204 of the second connecting portion 22 and the tab 301. In some embodiments, the circumferential outer edge of the first insulating portion 31 has a first inclined structure 311. The first inclined structure 311 is inclined from the side of the first insulating portion 31 that contacts the second surface 12 toward the surface of the first insulating portion 31 facing the interior of the housing. It can be understood that, along the width and length directions of the cover plate 10, the size of the contact surface between the first insulating portion 31 and the second surface 12 is larger than the size of the surface of the first insulating portion 31 facing the interior of the housing, so that the first insulating portion 31 can abut against the second surface 12 of the cover plate 10. From the three cross-sectional views of FIG8, FIG16, and FIG30, the first inclined structure 311 and the second surface 12 are set at an obtuse angle.

[0230] In some embodiments, the third insulating portion 33 covers the surface of the pole post 20 located on the side of the first surface 11, and at least exposes the first electrical connection surface 102 of the first connecting portion 21. While ensuring that the third insulating portion 33 can cover the surface of the pole post 20 located on the first surface 11 to insulate it from the cover plate 10, the first electrical connection surface 102 is exposed so that it can be connected to an electrical connector. When the second connecting portion 22 and the tab 301 are welded using a pressure welding method, the third insulating portion 33 can expose at least a portion of the upper surface of the second connecting portion 22 to facilitate electrical connection between the electrode of the pressure welding device and the second connecting portion 22. This upper surface refers to the surface of the second connecting portion 22 away from the interior of the housing.

[0231] As one embodiment of the third insulating part 33, as shown in Figures 13, 14, and 15, the third insulating part 33 includes a first sub-insulating part 331 and a second sub-insulating part 332 covering the first connecting part 21. The first sub-insulating part 331 fills the space between the lower surface of the base part 211 and the bottom of the second groove 14. The second sub-insulating part 332 covers the circumferential sidewall of the base part 211, the circumferential sidewall of the first electrical connecting part 212, and the third stepped surface 105 formed by the circumferential sidewall of the base part 211 and the circumferential sidewall of the first electrical connecting part 212. The surface of the second sub-insulating part 332 facing away from the housing is flush with the first stepped surface 104, preventing the second sub-insulating part 332 from interfering with the welding of the first electrical connecting surface 102 of the first connecting part 21 to the electrical connector.

[0232] As shown in Figures 13, 14 and 15, the third insulating part 33 also includes a third sub-insulating part 333 covering the second connecting part 22. The third sub-insulating part 333 covers the lower surface of the flange 23 of the second connecting part 22 facing the inside of the housing, the circumferential side wall surface of the flange 23, and the upper surface of the flange 23 facing the outside of the housing. When the second connecting part 22 has a first groove 24, the third sub-insulating part 333 also covers the bottom surface and side surface of the first groove 24.

[0233] Referring to Figures 19, 20, and 21, in another embodiment of the third insulating portion 33, the third insulating portion 33 includes a first sub-insulating portion 331 and a second sub-insulating portion 332. The first sub-insulating portion 331 fills the space between the lower surface of the base portion 211 and the fourth surface 151 of the support portion 15. The second sub-insulating portion 332 covers the circumferential sidewall of the base portion 211. The surface of the second sub-insulating portion 332 facing away from the housing is flush with the first stepped surface 104, preventing the second sub-insulating portion 332 from interfering with the welding of the first electrical connection surface 102 of the first connecting portion 21 to the electrical connector.

[0234] The third insulating part 33 also includes a third sub-insulating part 333 covering the second connecting part 22. When the second connecting part 22 is not provided with the flange 23 and the first groove 24, that is, the third surface 202 of the second connecting part 22 is a continuous planar structure, in this embodiment, the third sub-insulating part 333 can cover the edge of the third surface 202 and the edge of the first through hole 13 along the edge of the third surface 202.

[0235] When the pole post 20 also includes the transition portion 25, as shown in Figures 19 and 20, the third insulating portion 33 also includes a fourth sub-insulating portion 334, which covers the transition portion 25 between the inner surface facing the inside of the housing and the outer surface facing the outside of the housing.

[0236] In some embodiments, the outer circumferential edge of the third insulating portion 33 is set at an obtuse angle to the first surface 11 of the cover plate 10. It is understood that the outer circumferential edge of the third insulating portion 33 may be the portion of the third insulating portion 33 covering the side surfaces of the first connecting portion 21 and the second connecting portion 22. By setting the outer circumferential edge of the third insulating portion 33 at an obtuse angle to the first surface 11 of the cover plate 10, the thickness of the third insulating portion 33 of the first insulating member 30 along the width direction of the cover plate 10 can be appropriately reduced, while the draft angle formed by the obtuse angle facilitates smooth demolding of the mold.

[0237] In some embodiments, as shown in FIG8, when the first surface 11 of the cover plate 10 is provided with the second groove 14, the distance between the outer circumferential edge of the third insulating part 33 and the groove wall of the second groove 14 is 'a', satisfying: 0.3mm ≤ a ≤ 2mm. For example, 'a' can be located within multiple ranges such as 0.3mm ≤ a ≤ 1.5mm, 0.3mm ≤ a ≤ 1mm, 0.3mm ≤ a ≤ 0.8mm, etc. Specifically, 'a' = 0.3mm, 0.5mm, 0.7mm, 0.9mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2.0mm, including but not limited to the values ​​listed above. Other values ​​between any two of the above are still applicable. Through the above arrangement, the third insulating part 33 can be sealed on the outside of the groove wall of the second groove 14, and the outer circumferential edge of the third insulating part 33 is not too close to the edge of the cover plate 10. When a is less than 0.3 mm, errors in manufacturing and mold positioning may cause the outer circumferential edge of the third insulating part 33 to shift into the second groove 14, exposing the second groove 14 and affecting the sealing performance. When a is greater than 2 mm, the outer circumferential edge of the third insulating part 33 is too close to the edge of the cover plate 10. During the welding of the cover plate 10 to the housing, the first insulating component 30 will be melted and blackened, affecting the insulation and sealing performance of the first insulating component 30.

[0238] As another embodiment of the first insulating member 30 of this application, as shown in Figures 32 and 33, the first insulating member 30 may include a second insulating portion 32 and a third insulating portion 33. That is, in this embodiment, the first insulating member 30 does not include a first insulating portion 31. In this case, the second insulating portion 32 is disposed between the hole wall of the first through hole 13 and the second connecting portion 22 of the electrode post 20, so as to connect the second connecting portion 22 and the hole wall of the first through hole 13 through the second insulating portion 32 and form insulation, and at the same time, it can play a sealing role to prevent electrolyte from leaking out of the first through hole 13. The second insulating portion 32 may be in the form of a ring structure, and the end of the second insulating portion 32 facing the outside of the housing is connected to the third insulating portion 33. The third insulating portion 33 is disposed on the side of the cover plate 10 having the first surface 11, that is, the third insulating portion 33 is disposed on the outer side of the cover plate 10. It can be understood that the third insulating portion 33 covers the electrode portion located on the outer side of the cover plate 10 to insulate the electrode portion located on the first surface 11 of the cover plate 10 and the cover plate 10. Simultaneously, the third insulating portion 33 also serves a sealing function. The electrode portion located on the first surface 11 of the cover plate 10 includes a portion of the structure of the first connecting portion 21 and the second connecting portion 22. Along the thickness direction of the cover plate 10, at least a portion of the orthographic projection of the third insulating portion 33 falls on the cover plate 10, that is, on a virtual plane perpendicular to the thickness direction of the cover plate 10, the orthographic projection of the third insulating portion 33 overlaps with the orthographic projection of the cover plate 10. It can be understood that the outer contour edge of the third insulating portion 33 protrudes from the wall of the first through hole 13. The second insulating portion 32 and the third insulating portion 33 can be integrally nano-injection molded. This can greatly improve the sealing performance of the battery cell, thus eliminating the need for the existing sealing ring structure. For other technical details in this embodiment, such as the cooperation relationship between the second insulating part 32 and the third insulating part 33 and the pole post 20 / cover plate 10, please refer to the content of the foregoing embodiment.

[0239] As another embodiment of the first insulating member 30 of this application, as shown in Figures 34 and 35, the first insulating member 30 may further include a first insulating portion 31, a second insulating portion 32, and a third insulating portion 33 connected together. In this embodiment, the second insulating portion 32 is disposed between the wall of the first through hole 13 and the second connecting portion 22 of the electrode post 20, so as to connect the second connecting portion 22 and the wall of the first through hole 13 through the second insulating portion 32 and form insulation, and at the same time, it can play a sealing role to prevent electrolyte from leaking out of the first through hole 13. The second insulating portion 32 may be in a ring shape, with one end of the second insulating portion 32 facing the inside of the housing connected to the first insulating portion 31, and the other end of the second insulating portion 32 facing the outside of the housing connected to the third insulating portion 33. In this embodiment, the first insulating part 31 is located on one side of the second surface 12 of the cover plate 10, and along the thickness direction of the cover plate 10, the orthographic projection of the first insulating part 31 falls entirely into the first through hole 13. That is, the first insulating part 31 extends from the end connected to the second insulating part 32 along the thickness direction of the cover plate 10, and its orthographic projection does not fall on the cover plate 10.

[0240] The third insulating portion 33 is disposed on the side of the cover plate 10 with the first surface 11, that is, the third insulating portion 33 is disposed on the outer side of the cover plate 10. It can be understood that the third insulating portion 33 covers the electrode portion located on the outer side of the cover plate 10 to insulate the electrode portion located on the first surface 11 of the cover plate 10 and the cover plate 10. Simultaneously, the third insulating portion 33 also serves a sealing function. The electrode portion located on the first surface 11 of the cover plate 10 includes a portion of the structure of the first connecting portion 21 and the second connecting portion 22. Along the thickness direction of the cover plate 10, at least a portion of the orthographic projection of the third insulating portion 33 falls on the cover plate 10, that is, on a virtual plane perpendicular to the thickness direction of the cover plate 10, the orthographic projection of the third insulating portion 33 overlaps with the orthographic projection of the cover plate 10. It can be understood that the outer contour edge of the third insulating portion 33 protrudes from the wall of the first through hole 13. The first insulating portion 31, the second insulating portion 32, and the third insulating portion 33 can be integrally nano-injection molded. This can greatly improve the sealing performance of the battery cell. For other technical details in this embodiment, such as the cooperation relationship between the second insulating part 32 and the third insulating part 33 and the pole post 20 / cover plate 10, please refer to the content of the foregoing embodiment.

[0241] As one embodiment of the top cover assembly, please refer to Figures 6 and 28. The cover plate 10 may also be provided with a second insulating member 40. The second insulating member 40 is disposed on the second surface 12 of the cover plate 10 and is used to insulate the cover plate 10 and the electrode assembly 300 to reduce the risk of short circuit. For example, the second insulating member 40 may be a plastic material, such as PP, PE, PPS, etc.

[0242] Specifically, the second insulating member 40 is provided with a second through hole 41 corresponding to the first through hole 13. The second through hole 41 penetrates the thickness direction of the second insulating member 40. The second connecting part 22 passes through the first through hole 13 and the second through hole 41 in sequence so that the second connecting part 22 can be welded to the tab 301.

[0243] As one embodiment of the second insulating member 40, referring to Figures 8, 16, and 30, the second insulating member 40 has a second inclined structure 43 that matches the first inclined structure 311, and the second inclined structure 43 abuts against the first inclined structure 311. This allows the second insulating member 40 to cooperate and abut against the first insulating member 30, increasing the connection reliability between the first insulating member 30 and the cover plate 10, further improving the fixing effect on the electrode post 20, and facilitating the second insulating member 40 to insulate the cover plate 10 and the electrode assembly 300, thus preventing the second insulating member 40 from affecting the sealing performance of the first insulating member 30 and the performance of other structural components.

[0244] In some embodiments, as shown in FIG30, the surface of the second insulating member 40 facing away from the cover plate 10 is flush with the surface of the first insulating portion 31 facing away from the cover plate 10. That is, the surface of the second insulating member 40 facing the interior of the housing is flush with the surface of the first insulating portion 31 facing the interior of the housing. With this configuration, when the second insulating member 40 is heat-fused and fixed to the cover plate 10, the surface is flat and convenient for fixture pressing. In some other embodiments, as shown in FIG16 or FIG32 to 34, the second insulating member 40 may also extend to the second stepped surface 203 of the second connecting portion 22. In this case, the second insulating member 40 covers the circumferential outer edge and bottom surface of the first insulating portion 31. With this configuration, the second insulating member 40 covers the contact interface between the first insulating portion 31 and the cover plate 10, preventing electrolyte from flowing into the first through hole 13 from the contact interface.

[0245] Referring to Figure 6, the cover plate 10 may also be provided with a pressure relief mechanism 50 for releasing internal pressure when the internal pressure or temperature of the battery cell reaches a threshold. The surface of the pressure relief mechanism 50 facing the outer side of the casing is provided with a protective layer 60 to protect the pressure relief mechanism 50. By providing a pressure relief mechanism 50 on the cover plate 10, thermal runaway of the battery cell is less likely to occur.

[0246] In some embodiments, as shown in Figures 36 to 45, a sealing ring 80 is added to the top cover assembly, the first insulating part 31 and the second insulating part 32 are eliminated, and only the third insulating part 33 is retained.

[0247] Please refer to Figures 39 to 41. In the embodiments of this application, each second connecting portion 22 includes a first region 224 and a second region 225 arranged around the first region 224. The second region 225 is connected to the first connecting portion 21. The first region 224 protrudes relative to the second region 225 in a direction from the first surface 11 to the second surface 12, forming a connecting sub-portion 223 that passes through the corresponding first through hole 13. Thus, the first region 224 of the second connecting portion 22 can be drawn once or multiple times using a stamping process, so that the first region 224 protrudes relative to the second region 225 toward the cover plate 10 to form the connecting sub-portion 223. The connecting sub-portion 223 extends through the corresponding first through hole 13 to the tab 301 of the corresponding electrode assembly 300 and is directly connected to the tab 301. It should be noted that the first region 224 corresponds to the region where the connecting sub-part 223 is located, and the bottom wall of the groove of the connecting sub-part 223 forms the second electrical connection part 240. The second region 225 corresponds to the region where the flange part 23 is located.

[0248] In some embodiments, the end of the connecting part 223 away from the second region 225 is a welding end a3, which passes through the corresponding first through hole 13 and enters the receiving cavity of the housing 200. That is, the welding end a3 of the connecting part 223 protrudes from the second surface 12 of the cover plate 10, thereby avoiding welding the tab 301 and the welding end a3 of the connecting part 223 inside the first through hole 13, greatly reducing the welding difficulty and improving the welding quality of the tab 301 and the welding end a3 of the connecting part 223.

[0249] In some embodiments, the welding end a3 of the connecting part 223 protrudes from the second surface 12 of the cover plate 10 along the thickness direction of the cover plate 10 by a distance of 0 to 5 mm, thereby avoiding the large space occupied in the receiving cavity due to the welding end a3 protruding too far from the second surface 12, that is, saving the space in the receiving cavity of the housing 200, which is beneficial to improving the energy density of the battery.

[0250] In some embodiments, the top cover assembly 100 further includes a second insulating member 40 disposed on the second surface 12 of the cover plate 10, for forming insulation between the cover plate 10 and the electrode assembly 300. The second insulating member 40 has a second through hole 41 opposite to the first through hole 13, and the connecting portion 223 passes through the corresponding first through hole 13 and second through hole 41. The welding end a3 of the connecting portion 223 has a welding surface a4, which protrudes from the surface of the second insulating member 40 away from the cover plate 10, or the welding surface a4 is flush with the surface of the second insulating member 40 away from the cover plate 10. This avoids welding the tab 301 to the welding surface a4 of the connecting portion 223 inside the second through hole 41, greatly reducing the welding difficulty and improving the welding quality of the tab 301 and the welding surface a4 of the connecting portion 223.

[0251] It should be noted that welding processes such as laser welding, resistance welding, ultrasonic welding, and pressure fusion welding can be used to weld the connecting part 223 to the tab 301.

[0252] In one embodiment, the tab 301 is welded and fixed to the connector 223 by pressure welding. Specifically, a protrusion 227 is provided on the welding surface a4 of the connector 223. During pressure welding, the tab 301 contacts the protrusion 227. Since the flow area at the contact point between the tab 301 and the protrusion 227 is small, the heat generated is large, causing the protrusion 227 to melt and weld the tab 301 to the welding surface a4 of the connector 223. It is understood that the shape of the protrusion 227 can be spherical, hemispherical, frustum-shaped, etc., as long as it can ensure that the protrusion 227 can melt under the action of electrical energy and pressure to weld the tab 301 to the welding surface a4 of the connector 223. No limitation is made here.

[0253] In another embodiment, the tab 301 is welded and fixed to the connector 223 by laser welding. Specifically, the distance between the weld mark on the welding surface a4 of the welding end a3 and the edge of the welding surface a4 is greater than or equal to 1 mm. Optionally, the distance between the weld mark on the welding surface a4 and the edge of the welding surface a4 can be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2.0 mm, etc., and is not specifically limited here.

[0254] It should be noted that the distance between the weld mark on the welding surface a4 and the edge of the welding surface a4 refers to the distance between any point on the edge of the welding surface a4 and any point on the edge of the weld mark.

[0255] Specifically, in this embodiment, the end face of the connecting sub-part 223 that connects to the second region 225 has a first groove 24, making the connecting sub-part 223 a hollow structure, which helps to reduce the weight of the pole post 20 and save the material of the pole post 20. It can be understood that during one or more deep drawing processes of the sheet material, the first region 224 of the sheet material bulges outward to one side relative to the second region 225, thereby forming the hollow connecting sub-part 223.

[0256] Optionally, the depth of the first groove 24 is 1mm to 5mm, preferably 1mm to 3mm. If the depth of the first groove 24 is too shallow, the welding end a3 of the connecting part 223 will be far from the electrode assembly 300, requiring a longer tab 301; if the depth of the first groove 24 is too deep, the deep drawing process will be more difficult. In this embodiment, by reasonably designing the depth of the first groove 24, the depth of the first groove 24 is made moderate, which allows welding of the tab 301 to the welding end a3 of the connecting part 223 without lengthening the tab 301, while also reducing the difficulty of the deep drawing process, improving production efficiency and the yield of the electrode post 20.

[0257] It should be noted that the depth of the first groove 24 can be 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm or 5.0mm, etc., and no special limitation is made here.

[0258] In the embodiments of this application, the pole post 20 further includes a transition portion 25, and the second region 225 of each second connecting portion 22 is connected to the first connecting portion 21 through the transition portion 25. The end of the transition portion 25 connected to the second region 225 of the second connecting portion 22 is the first end, and the first end protrudes at least partially from the side surface of the first connecting portion 21 facing the cover plate 10 along the thickness direction of the pole post 20. That is, the transition portion 25 extends obliquely from the end connected to the first connecting portion 21 to the end connected to the second region 225 relative to the thickness direction of the pole post 20, so that the second connecting portion 22 sinks towards the cover plate 10 relative to the first connecting portion 21, thereby making the connecting sub-part 223 closer to the corresponding tab 301, which is beneficial to minimize the drawing depth of the connecting sub-part 223, reduce the drawing difficulty, and improve the drawing quality of the pole post 20.

[0259] In some embodiments, the current-carrying area of ​​the transition portion 25 is smaller than that of the first connecting portion 21 and smaller than that of the second connecting portion 22. Thus, in actual use, when a circuit malfunction occurs, the smaller current-carrying area of ​​the transition portion 25 causes it to heat up more quickly, allowing it to melt rapidly and disconnect the circuit promptly, greatly improving battery safety. It is understood that the current-carrying area of ​​the transition portion 25 can be reduced by slotting, opening, and / or locally thinning to ensure timely melting and circuit disconnection in case of a circuit malfunction.

[0260] In the embodiments of this application, the third insulating part 33 includes a first sub-insulating part 331. The first sub-insulating part 331 is disposed between the first connecting part 21 of the pole post 20 and the cover plate 10 and forms an insulation, that is, it prevents the first connecting part 21 of the pole post 20 from being electrically connected to the cover plate 10.

[0261] In some embodiments, the third insulating portion 33 further includes a third sub-insulating portion 333, which covers the second region 225 of the pole post 20. On the one hand, it provides insulation protection for the outer surface of the second region 225, and on the other hand, it wraps the second region 225 of the pole post 20, which helps to increase the overall strength of the pole post 20 and reduce the risk of deformation of the pole post 20.

[0262] In some embodiments, the third sub-insulating part 333 also covers the inner wall of the first groove 24, which on the one hand provides insulation protection for the inner wall of the first groove 24, and on the other hand helps to increase the bonding force between the third sub-insulating part 333 and the second connecting part 22, greatly reducing the risk of positional displacement or even separation between the third sub-insulating part 333 and the second connecting part 22.

[0263] In some embodiments, the third sub-insulator 333 is recessed into the first groove 24 to form a pit 361. That is, the third sub-insulator 333 only covers the inner wall of the first groove 24 and does not fill the first groove 24. On the one hand, this helps to improve the bonding force between the third sub-insulator 333 and the second connecting part 22 of the pole post 20, and avoids the separation or misalignment of the third sub-insulator 333 and the second connecting part 22. On the other hand, it reduces the amount of material used in the third sub-insulator 333 and avoids defects such as uneven injection molding caused by excessive local thickness.

[0264] In some embodiments, the third sub-insulating portion 333 further extends to and covers each transition portion 25, thereby providing insulation protection for the surface of the transition portion 25. The third insulating portion 33 also includes a second sub-insulating portion 332. The second sub-insulating portion 332 extends along the peripheral edge of the first connecting portion 21 and covers the peripheral edge of the third sub-insulating portion 333, thereby improving the overall strength of the pole post 20 and providing insulation protection for the peripheral edge of the first connecting portion 21. That is, the surface of the first connecting portion 21 facing the cover plate 10 is covered by the first sub-insulating portion 331, and the peripheral edge of the first connecting portion 21 is covered by the second sub-insulating portion 332. Only the surface of the first connecting portion 21 facing away from the cover plate 10 is not covered, and this uncovered surface is used for welding with electrical connectors.

[0265] Specifically, in this embodiment, the first connecting portion 21 has a first electrical connecting portion 212 and a first stepped surface 104 on the side facing away from the cover plate 10. The first stepped surface 104 is arranged around the first electrical connecting portion 212, and the first electrical connecting portion 212 protrudes relative to the first stepped surface 104 in the direction away from the cover plate 10. The electrical connector is welded to the first electrical connecting portion 212, and the second sub-insulating portion 332 of the third insulating portion 33 is lower than or flush with the first stepped surface 104. Thus, by providing the first electrical connecting portion 212, during injection molding, the flow of injection molding material to the surface of the first electrical connecting portion 212 can be prevented, causing the third insulating portion 33 to cover the surface of the first electrical connecting portion 212.

[0266] Optionally, the protrusion height of the first electrical connection portion 212 relative to the first stepped surface 104 is 0.05mm to 0.8mm, preferably 0.1mm to 0.6mm or 0.3mm to 0.5mm. It should be noted that the protrusion height of the first electrical connection portion 212 relative to the first stepped surface 104 can be 0.05mm, 0.20mm, 0.35mm, 0.50mm, 0.65mm or 0.8mm, etc., and is not specifically limited here.

[0267] In some embodiments, the transition portion 25 has at least one third through hole 254, and the third insulating portion 33 further includes a fifth sub-insulating portion 335 filled in the third through hole 254. The fifth sub-insulating portion 335 is connected to the first sub-insulating portion 331, the third sub-insulating portion 333, and the second sub-insulating portion 332, thereby forming a whole from the first sub-insulating portion 331, the third sub-insulating portion 333, the fifth sub-insulating portion 335, and the second sub-insulating portion 332. This is beneficial for improving the bonding force between the third insulating portion 33 and the pole post 20, and for further enhancing the overall strength of the pole post 20.

[0268] In some embodiments, the first sub-insulating portion 331, the third sub-insulating portion 333, the second sub-insulating portion 332, and the fifth sub-insulating portion 335 of the third insulating portion 33 are integrally formed, for example, by injection molding. During injection molding of the third insulating portion 33, a portion of the molten injection material flows to the surfaces of each of the second connecting portions 22 and each of the transition portions 25, and solidifies to form the third sub-insulating portion 333; a portion of the molten injection material flows to the surface of the peripheral edge of the first connecting portion 21, and solidifies to form the second sub-insulating portion 332; a portion of the injection material flows into the third through hole 254, and solidifies to form the fifth sub-insulating portion 335; a portion of the injection material flows through the third through hole 254 into the space between the first connecting portion 21 and the cover plate 10, and solidifies to form the first sub-insulating portion 331 between the first connecting portion 21 and the cover plate 10.

[0269] It should be noted that the third through hole 254 on the transition section 25 serves two purposes: firstly, it facilitates the flow of injection molding material during injection molding; secondly, it reduces the flow area of ​​the transition section 25, ensuring that the transition section 25 can melt and cut off the circuit in time in case of an abnormality.

[0270] Please refer to Figure 42. In a specific embodiment, the top cover assembly 100 also includes a first fixing part 70. The first fixing part 70 is fixedly connected to the first surface 11 of the cover plate 10, and a portion of the first fixing part 70 can be bent to the side surface of the third sub-insulator 333 facing away from the cover plate 10 by a rolling process, thereby using the first fixing part 70 to press the third sub-insulator 333 and the pole post 20 onto the cover plate 10, preventing the pole post 20 from detaching from the cover plate 10.

[0271] In some embodiments, the third sub-insulator 333 has a stepped surface a6 extending along the peripheral edge of the second region 225 of the second connecting portion 22. The first fixing portion 70 extends along the peripheral edge of the second connecting portion 22 and presses against the stepped surface a6, making the pressure of the first fixing portion 70 on the third sub-insulator 333 more stable, thereby making the assembly structure of the pole post 20 and the cover plate 10 more stable and preventing the pole post 20 from shifting position or even detaching from the cover plate 10.

[0272] It should be noted that the number of first fixing parts 70 is the same as the number of second connecting parts 22, and they are arranged in a one-to-one correspondence. Each first fixing part 70 presses against the third sub-insulating part 333 on the surface of the corresponding second connecting part 22, thereby pressing each second connecting part 22 of the pole post 20 against the cover plate 10. Optionally, each first fixing part 70 extends in a C-shape along the peripheral edge of the corresponding second connecting part 22, and the opening of the C-shaped first fixing part 70 faces the first connecting part 21, so that the transition part 25 passes through the opening of the first fixing part 70, avoiding interference with the rolling equipment caused by the second sub-insulating part 332 covering the peripheral edge of the first connecting part 21 and the third sub-insulating part 333 covering the transition part 25 when the first fixing part 70 is rolled.

[0273] Specifically, the first fixing part 70 includes a first arc segment 75, a straight edge segment 77, and a second arc segment 79 connected in sequence, with both the first arc segment 75 and the second arc segment 79 located on the side of the straight edge segment 77 facing the first connecting part 21. A clearance space a5 is formed between the end of the first arc segment 75 away from the straight edge segment 77 and the end of the second arc segment 79 away from the straight edge segment 77. It can be understood that this clearance space a5 is the space at the opening of the C-shaped first fixing part 70.

[0274] Optionally, the central angle of the first arc segment 75 is greater than 90°, which is beneficial to extend the length of the first fixing part 70, so that the first fixing part 70 can more firmly press the third sub-insulating part 333 and the second connecting part 22 onto the cover plate 10.

[0275] Optionally, the central angle of the second arc segment 79 is greater than 90°, which is beneficial to extend the length of the first fixing part 70, so that the first fixing part 70 can more firmly press the third sub-insulating part 333 and the second connecting part 22 onto the cover plate 10.

[0276] It should be noted that in order to improve the pressing effect, the length of the first fixing part 70 needs to be extended as much as possible. However, extending the length of the first fixing part 70 will cause the distance between the end of the first arc segment 75 and / or the second arc segment 79 away from the straight edge segment 77 and the first connecting part 21 to be too close. This will cause the second sub-insulating part 332 wrapped around the periphery of the first connecting part 21 to interfere with the rolling device when the first fixing part 70 is rolled.

[0277] To prevent interference between the second sub-insulating portion 332, which wraps around the periphery of the first connecting portion 21, and the hemming equipment during the hemming operation of the first arc segment 75, in some embodiments, the distance between the end of the first arc segment 75 away from the straight edge segment 77 and the first connecting portion 21 is greater than or equal to 1.4 mm. This ensures that the distance between the end of the first arc segment 75 away from the straight edge segment 77 and the first connecting portion 21 is sufficiently large to prevent interference between the second sub-insulating portion 332 and the hemming equipment during the hemming operation of the first arc segment 75.

[0278] It should be noted that the distance between the end of the first arc segment 75 away from the straight edge segment 77 and the first connecting part 21 can be 1.4mm, 1.5mm, 1.6mm, 1.7mm or 1.8mm, etc., and no special limitation is made here.

[0279] To prevent interference between the second sub-insulating portion 332, which wraps around the periphery of the first connecting portion 21, and the hemming device during the hemming operation of the second arc segment 79, in some embodiments, the distance between the end of the second arc segment 79 away from the straight edge segment 77 and the first connecting portion 21 is greater than or equal to 1.4 mm. This ensures that the distance between the end of the second arc segment 79 away from the straight edge segment 77 and the first connecting portion 21 is sufficiently large to prevent interference between the second sub-insulating portion 332 and the hemming device during the hemming operation of the second arc segment 79.

[0280] It should be noted that the distance between the end of the second arc segment 79 away from the straight edge segment 77 and the first connecting part 21 can be 1.4mm, 1.5mm, 1.6mm, 1.7mm or 1.8mm, etc., and no special limitation is made here.

[0281] Specifically, in this embodiment, the first fixing part 70 includes a standing edge part 71 and a flanged edge part 73. The standing edge part 71 is connected to the first surface 11 of the cover plate 10. The flanged edge part 73 is connected to the standing edge part 71, and the flanged edge part 73 is bent relative to the standing edge part 71 onto the stepped surface a6 of the third sub-insulating part 333, thereby pressing the third sub-insulating part 333 with the flanged edge part 73, thereby pressing and fixing the third insulating part 33 and the pole post 20 onto the cover plate 10.

[0282] In some embodiments, an insulating gap 730 is provided between the end of the flanged portion 73 away from the upright portion 71 and the second region 225 of the second connecting portion 22. A portion of the third sub-insulating portion 333 fills the insulating gap 730, thereby achieving insulation between the flanged portion 73 and the second region 225 of the second connecting portion 22.

[0283] To more securely press the second connecting portion 22 onto the cover plate 10, in some embodiments, the orthographic projection of the flange portion 73 along the thickness direction of the cover plate 10 onto the cover plate 10 is a first orthographic projection, and the orthographic projection of the second connecting portion 22 along the thickness direction of the cover plate 10 onto the cover plate 10 is a second orthographic projection. The first orthographic projection of the flange portion 73 and the second orthographic projection of the second connecting portion 22 partially overlap, meaning that the flange portion 73 and the second connecting portion 22 overlap in the thickness direction of the cover plate 10.

[0284] In other embodiments, the first orthographic projection of the flange portion 73 does not coincide with the second orthographic projection of the second connecting portion 22, that is, the flange portion 73 and the second connecting portion 22 do not overlap in the thickness direction of the cover plate 10.

[0285] It should also be noted that, since each of the second connecting parts 22 is pressed onto the cover plate 10 by the first fixing part 70, and the bond between the first connecting part 21 and the cover plate 10 is relatively weak, the pole post 20 may experience uneven stress, leading to warping or even cracking. To prevent the pole post 20 from warping or cracking due to uneven stress, in some embodiments, a fourth groove 210 is formed on the surface of the first connecting part 21 facing the cover plate 10, and a third groove 17 is formed on the surface of the cover plate 10 facing the first connecting part 21. A portion of the first sub-insulating part 331 fills the fourth groove 210, and a portion of the first sub-insulating part 331 also fills the third groove 17. Thus, when the third insulating part 33 is injection molded, the molten injection material can flow into the fourth groove 210 and the third groove 17, and after solidification, form a structure in which a portion of the first sub-insulating part 331 fills the fourth groove 210 and the third groove 17, which helps to improve the bonding force between the first connecting part 21, the first sub-insulating part 331, and the cover plate 10.

[0286] In some embodiments, at least a portion of the fourth groove 210 gradually narrows or tapers in a stepped manner from the bottom to the opening, thereby ensuring that the first sub-insulator 331 is tightly nested on the pole post 20, preventing the pole post 20 from separating from the third insulation portion 33. At least a portion of the third groove 17 gradually narrows or tapers in a stepped manner from the bottom to the opening, thereby ensuring that the first sub-insulator 331 is tightly nested on the cover plate 10, preventing the cover plate 10 from separating from the third insulation portion 33.

[0287] Optionally, the depth of the fourth groove 210 is h1, and the thickness of the first connecting portion 21 is H1, where h1 and H1 satisfy: h1 = (5%~50%) × H1. Preferably, h1 and H1 satisfy: h1 = (10%~20%) × H1. Thus, by designing the depth of the fourth groove 210 within a suitable range, on the one hand, it avoids the fourth groove 210 being too shallow, resulting in an insignificant effect on increasing the bonding force between the first sub-insulator 331 and the first connecting portion 21; on the other hand, it avoids the fourth groove 210 being too deep, resulting in low strength of the first connecting portion 21 and easy deformation. It should be noted that h1 can be 5% × H1, 10% × H1, 15% × H1, 20% × H1, 25% × H1, 30% × H1, 35% × H1, 70% × H1, 75% × H1, or 50% × H1, etc., and is not specifically limited here.

[0288] Optionally, the depth of the third groove 17 is h2, and the thickness of the cover plate 10 is T2, where h2 and T2 satisfy: h2 = (5%~50%)T2. Preferably, h2 and T2 satisfy: h2 = (10%~20%)×T2. Thus, by designing the depth of the third groove 17 within a suitable range, on the one hand, it avoids the third groove 17 being too shallow, resulting in an insignificant effect on increasing the bonding force between the first sub-insulator 331 and the cover plate 10; on the other hand, it avoids the third groove 17 being too deep, resulting in weak strength of the cover plate 10 and easy deformation. It should be noted that h2 can be 5%×T2, 10%×T2, 15%×T2, 20%×T2, 25%×T2, 30%×T2, 35%×T2, 70%×T2, 75%×T2, or 50%×T2, etc., and is not specifically limited here.

[0289] Please refer to Figures 38, 41, and 42. In a specific embodiment, the top cover assembly 100 further includes a sealing ring 80, which comprises a first sealing portion 81 and a second sealing portion 82. Both the first sealing portion 81 and the second sealing portion 82 are sleeved on the connecting sub-part 223. The first sealing portion 81 is located between the inner wall of the first through hole 13 and the connecting sub-part 223, and the second sealing portion 82 is located between the surface of the cover plate 10 facing away from the electrode assembly 300 and the second region 225. Thus, on the one hand, the sealing ring 80 seals the first through hole 13 on the cover plate 10, preventing electrolyte leakage from the housing 200 through the first through hole 13; on the other hand, the sealing ring 80 forms insulation between the connecting sub-part 223, the second region 225, and the cover plate 10, preventing electrical conduction between the electrode post 20 and the cover plate 10. It should be noted that under the pressure of the flanged part 73, the first sealing part 81 and the second sealing part 82 of the sealing ring 80 are in a compressed state, thereby sealing the first through hole 13.

[0290] In some embodiments, the first surface 11 of the cover plate 10 has a first protrusion 18 surrounding the first through hole 13. The second sealing part 82 presses against the first protrusion 18, which helps to increase the contact area between the sealing ring 80 and the cover plate 10, extend the sealing path, and improve the sealing effect.

[0291] It should be noted that the first protrusion 18 is provided around the first through hole 13 on the first surface 11 of the cover plate 10, which can also strengthen the area of ​​the cover plate 10 near the first through hole 13, greatly reducing the risk of deformation or warping of the cover plate 10.

[0292] In some embodiments, the sealing ring 80 further includes a second protrusion 83. The second protrusion 83 protrudes from the side of the second sealing portion 82 opposite to the cover plate 10 and is arranged around the second region 225. That is, the second sealing portion 82 contacts the entire surface of the second region 225 facing the cover plate 10, and the second protrusion 83 on the second sealing portion 82 extends to the end face of the second region 225, which helps to further improve the sealing effect.

[0293] In some embodiments, the second protrusion 83 extends in a C-shape along the peripheral edge of the second region 225, and the opening of the second protrusion 83 faces the first connecting portion 21. Thus, since the second region 225 of the second connecting portion 22 is connected to the first connecting portion 21 through the transition portion 25, the second protrusion 83 is set in a C-shape, utilizing the space at the opening of the second protrusion 83 for the transition portion 25 to pass through, thereby avoiding interference between the second protrusion 83 and the transition portion 25.

[0294] Specifically, in the embodiment, on a dummy plane perpendicular to the thickness direction of the cover plate 10, the orthographic projection of the first connecting part 21 does not coincide with the orthographic projection of the first through hole 13, and the orthographic projection of the second connecting part 22 covers the orthographic projection of the first through hole 13. This makes the welding position of the first connecting part 21 to the electrical connector sufficiently far from each of the second connecting parts 22. Thus, when the electrical connector is welded to the first electrical connecting part 212 of the first connecting part 21, the adverse effects of the heat generated by welding on the third insulating part 33 and the sealing ring 80 are greatly reduced. This helps to reduce the risk of cracking or heat melting of the third insulating part 33 and improve the sealing reliability of the sealing ring 80.

[0295] It should be noted that the top cover assembly 100 can be assembled by pre-injection molding or integral injection molding. Referring to Figure 44, pre-injection molding refers to: first, forming the pole post 20 using a stamping process; then, injection molding the third insulating part 33 onto the pole post 20, making the pole post 20 and the third insulating part 33 a single unit; next, fitting the sealing ring 80 onto the connecting part 223 of the pole post 20, and inserting the connecting part 223 of the pole post 20 into the first through hole 13 on the cover plate 10; then, rolling the first fixing part 70 so that the flanged part 73 of the first fixing part 70 bends onto the third sub-insulating part 333 of the third insulating part 33, thereby pressing the pole post 20 and the third insulating part 33 tightly onto the cover plate 10, while simultaneously compressing the sealing ring 80 to seal the first through hole 13.

[0296] In the pre-injection molding method, since the first fixing part 70 is rolled to a folded state only after the third insulating part 33 is injection molded, the third sub-insulating part 333 of the injection-molded third insulating part 33 does not cover the first fixing part 70.

[0297] Please refer to Figure 38. The one-piece injection molding method refers to the following steps: First, the pole post 20 is formed using a stamping process; then, the sealing ring 80 is fitted onto the connecting part 223 of the pole post 20, and the connecting part 223 is inserted into the first through hole 13 on the cover; then, the pole post 20, the sealing ring 80, and the cover plate 10 are installed as a whole into the injection mold for injection molding, and the third insulating part 33 is injection molded (the flanged part 73 of the first fixing part 70 has been rolled during the injection molding of the third insulating part 33). During the injection molding of the third insulating part 33, pressure is applied to the pole post 20, so that the pole post 20 compresses the sealing ring 80, so that the sealing ring 80 maintains a certain amount of compression; after the injection molding is completed, the cover plate 10, the sealing ring 80, the pole post 20, and the third insulating part 33 are removed from the injection mold as a whole. At this time, the pressure on the pole post 20 disappears, but due to the pressing action of the flanged part 73 of the first fixing part 70 against the third insulating part 33, the pole post 20 and the third insulating part 33 can remain pressed tightly on the cover plate 10, and the sealing ring 80 can also remain in a compressed state.

[0298] In the one-piece injection molding method, since the flanged sub-part 73 of the first fixing part 70 has been rolled to a folded state before the third insulating part 33 is injection molded, the third sub-insulating part 333 of the injection-molded third insulating part 33 also covers the flanged sub-part 73 and at least part of the upright sub-part 71 of the first fixing part 70.

[0299] In some embodiments, one second connecting portion 22, one first connecting portion 21, and one second connecting portion 22 are arranged at intervals along the width direction of the cover plate 10.

[0300] Of course, the positions of the two second connecting portions 22 are not limited to being located on both sides of the first connecting portion 21, as long as the two second connecting portions 22 are arranged along the width direction of the cover plate 10. In some other embodiments, the two second connecting portions 22 are located on the same side of the first connecting portion 21 in the length direction of the cover plate 10. In this way, by placing the two second connecting portions 22 on the same side of the first connecting portion 21, the size of the pole post 20 in the width direction of the cover plate 10 is further reduced, so as to adapt to the cover plate 10 with a narrower width.

[0301] The embodiment of the electrode post 20 being mounted on the cover plate 10 has been described above. However, the electrode post 20 is not limited to being mounted on the cover plate 10. In other embodiments, the electrode post 20 can also be mounted on the housing 200. Specifically, the battery cell includes a housing 200, an electrode assembly 300, an electrode post 20, and a third insulating portion 33. The housing 200 has a receiving cavity and a first wall serving as one side wall of the receiving cavity. The first wall has an inner side, an outer side, and a first through hole 13. The inner side faces the receiving cavity, and the outer side faces away from the receiving cavity. The first through hole 13 penetrates the inner side and the outer side. The electrode assembly 300 is received within the receiving cavity of the housing 200 and has at least two tabs 301 on the side facing the first wall. The electrode post 20 includes a first connecting portion 21 and at least two second connecting portions 22. The first connecting portion 21 is disposed on the outer side of the first wall, and each of the second connecting portions 22 is connected to the first connecting portion 21 and is arranged along the width direction of the first wall. Each second connecting portion 22 is at least partially inserted into the first through hole 13 and is connected to the corresponding tab 301. The third insulating portion 33 includes a first sub-insulating portion 331 disposed between the first connecting portion 21 and the first wall to form insulation.

[0302] It should be noted that the embodiment in which the pole post 20 is installed on the first wall of the housing 200 differs from the embodiment in which the pole post 20 is installed on the cover plate 10 only in the installation position of the pole post 20; the other structures are the same, so they will not be described in detail here.

[0303] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0304] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A cap assembly, characterized by, include: The cover plate (10) has a first surface (11), a second surface (12) and a first through hole (13), wherein the first surface (11) and the second surface (12) are arranged opposite to each other, and the first through hole (13) passes through the first surface (11) and the second surface (12); The pole post (20) includes at least one first connecting part (21) and at least two second connecting parts (22), and each first connecting part (21) is connected to two adjacent second connecting parts (22). The at least two second connecting parts (22) are arranged at intervals along the width direction of the cover plate (10). The first connecting part (21) is provided on the side of the cover plate (10) having the first surface (11) for connecting with an electrical connector. At least a portion of the second connecting part (22) passes through the first through hole (13) for connecting with the tab (301). The first insulating element (30) includes a third insulating portion (33), at least a portion of which is disposed between the first connecting portion (21) and the cover plate (10).

2. The roof assembly of claim 1, wherein, The first insulating member (30) further includes a first insulating part (31) and a second insulating part (32). The first insulating part (31) is disposed on the side of the cover plate (10) having the second surface (12). The second insulating part (32) is disposed between the hole wall of the first through hole (13) and the second connecting part (22) of the pole post (20). The third insulating part (33) is disposed on the side of the cover plate (10) having the first surface (11). The first insulating part (31), the second insulating part (32) and the third insulating part (33) are connected. On a virtual plane perpendicular to the thickness direction of the cover plate (10), the orthographic projection of the first insulating part (31) overlaps with the orthographic projection of the cover plate (10).

3. The roof assembly of claim 2, wherein, The second connecting portion (22) has a first groove (24) along the thickness direction of the cover plate (10), and the opening of the first groove (24) is formed on the surface of the second connecting portion (22) near the first connecting portion (21).

4. The roof assembly of claim 3, wherein, The second connecting part (22) has a flange (23) around the opening of the first groove (24). Along the thickness direction of the cover plate (10), the flange (23) is located on the side of the cover plate (10) having the first surface (11).

5. The roof assembly of claim 4, wherein, On a fictitious plane perpendicular to the thickness direction of the cover plate (10), the orthographic projection of the flange (23) overlaps with the orthographic projection of the cover plate (10).

6. The roof assembly of claim 4, wherein, The third insulating part (33) includes a first sub-insulating part (331) and a third sub-insulating part (333). The first sub-insulating part (331) is disposed between the first connecting part (21) and the cover plate (10). The third sub-insulating part (333) covers at least part of the flanged part (23).

7. The roof assembly of claim 6, wherein, The third sub-insulating part (333) also covers the inner wall of the first groove (24).

8. The roof assembly of claim 7, wherein, The third sub-insulating part (333) is recessed into the first groove (24) to form a pit (361).

9. The roof assembly of claim 6, wherein, The third insulating part (33) further includes a second sub-insulating part (332). The first connecting part (21) has a first electrical connecting part (212) and a first stepped surface (104) on the side away from the cover plate (10). The first stepped surface (104) is arranged around the first electrical connecting part (212), and the first electrical connecting part (212) protrudes in the direction away from the cover plate (10) relative to the first stepped surface (104). The second sub-insulating part (332) is arranged around the first connecting part (21) and covers the peripheral edge of the first connecting part (21). The second sub-insulating part is lower than the first stepped surface (104) or flush with the first stepped surface (104).

10. The roof assembly of claim 4, wherein, Along the thickness direction of the first connecting portion (21), the first connecting portion (21) includes a base portion (211) and a first electrical connection portion (212) stacked together. The upper surface of the flange portion (23) is flush with the upper surface of the base portion (211), and the lower surface of the flange portion (23) is flush with the lower surface of the base portion (211).

11. The roof assembly of claim 4, wherein, The end of the second connecting part (22) away from the flange part (23) is a welding end (a3), the welding end (a3) ​​has a welding surface (a4), and the welding surface (a4) protrudes from the second surface (12) of the cover plate (10).

12. The roof assembly of claim 11, wherein, Also includes: The second insulating element (40) is disposed on the side of the cover plate (10) having the second surface (12). The welding end (a3) ​​is disposed through the second insulating element (40), and the welding surface (a4) protrudes from the side surface of the second insulating element (40) away from the cover plate (10), or the welding surface (a4) is flush with the side surface of the second insulating element (40) away from the cover plate (10).

13. The roof assembly of claim 11, wherein, The welding end (a3) ​​protrudes from the second surface (12) along the thickness direction of the cover plate (10) by a distance of 0 to 5 mm.

14. The roof assembly of claim 11, wherein, The distance between the weld mark on the welding surface (a4) and the edge of the welding surface (a4) is greater than or equal to 1 mm.

15. The roof assembly of claim 4, wherein, The second connecting portion (22) includes a first metal layer (221) and a second metal layer (222). The first metal layer (221) and the second metal layer (222) are stacked along the thickness direction of the second connecting portion (22). At least a portion of the interface between the first metal layer (221) and the second metal layer (222) intersects with the side wall surface of the flange portion (23).

16. The roof assembly of claim 4, wherein, Along the width direction of the cover plate (10), the width of the cover plate (10) is W1, and the minimum distance between the side wall of the flange (23) and the edge of the cover plate (10) is W4. Satisfying: 5% ≤ W4 / W1 ≤ 20%; and / or, Satisfying: 3mm ≤ W4 ≤ 10mm; and / or, Satisfies: W1≥20mm.

17. The roof assembly of claim 3, wherein, The bottom surface of the first groove (24) is located between the first surface (11) and the second surface (12).

18. The roof assembly of claim 1, wherein, The second connecting part (22) is a plate-shaped structure. Along the thickness direction of the cover plate (10), the second connecting part (22) has a third surface (202) disposed near the first connecting part (21). The third surface (202) is located between the first surface (11) and the second surface (12).

19. The roof assembly of claim 18, wherein, The pole post (20) also includes a transition portion (25), which connects the first connecting portion (21) and the second connecting portion (22) along the width direction of the cover plate (10). At least a portion of the transition portion (25) is projected into the first through hole (13) along the thickness direction of the cover plate (10).

20. The roof assembly of claim 19, wherein, Along the length of the cover plate (10), the length of the transition portion (25) is less than the length of the first connecting portion (21) and less than the length of the second connecting portion (22); the first through hole (13) has a notch (16) for accommodating the transition portion (25).

21. The roof assembly of claim 1, wherein, The second connecting part (22) is a plate-shaped structure. Along the thickness direction of the cover plate (10), the second connecting part (22) has a third surface (202) disposed near the first connecting part (21). The third surface (202) is flush with the first surface (11) of the cover plate (10), or the third surface (202) protrudes from the first surface (11) of the cover plate (10).

22. The roof assembly of any one of claims 2 to 17, wherein, The first insulating part (31), the second insulating part (32) and the third insulating part (33) are integrally formed.

23. The top cover assembly according to any one of claims 2 to 17, characterized in that, The surfaces of the cover plate (10) that contact the first insulating part (31) and the second insulating part (32) are each provided with a first nanopore, and at least a portion of the first insulating part (31) and the second insulating part (32) is embedded in the first nanopore; and / or, The surfaces of the pole post (20) that are in contact with the first insulating part (31) and the second insulating part (32) are provided with second nanopores, and the first insulating part (31) and the second insulating part (32) are at least partially embedded in the second nanopores.

24. The top cover assembly according to claim 23, characterized in that, On a dummy plane perpendicular to the thickness direction of the cover plate (10), the orthographic projection of the third insulating part (33) overlaps with the orthographic projection of the cover plate (10). A third nanopore is provided on the surface of the cover plate (10) that contacts the third insulating part (33), and at least a portion of the third insulating part (33) is embedded in the third nanopore; and / or, The surface of the pole post (20) that contacts the third insulating part (33) is provided with a fourth nanopore, and at least a portion of the third insulating part (33) is embedded in the fourth nanopore.

25. The top cover assembly according to any one of claims 2 to 17, characterized in that, Along the thickness direction of the cover plate (10), the orthographic projection of the first connecting part (21) on the cover plate (10) does not overlap with the first through hole (13). The outer contour of the first connecting part (21) has at least a first outer peripheral surface (101). Along the width direction of the cover plate (10), the minimum distance between the first outer peripheral surface (101) and the hole wall of the first through hole (13) is W5, satisfying: 0≤W5≤10mm; and / or, Along the thickness direction of the cover plate (10), the orthographic projection of the first connecting part (21) on the cover plate (10) partially overlaps with the first through hole (13). The outer contour of the first connecting part (21) has at least a first outer peripheral surface (101). Along the width direction of the cover plate (10), the distance between the first outer peripheral surface (101) and the hole wall of the first through hole (13) is W5, which satisfies: 0≤W5≤10mm.

26. The roof assembly of any of claims 2 to 17, wherein, The first surface (11) of the cover plate (10) is provided with a second groove (14), which is recessed from the first surface (11) to the second surface (12). The cover plate (10) includes at least two first through holes (13), and each second connecting part (22) is correspondingly inserted into one of the first through holes (13). The at least two first through holes (13) respectively penetrate the bottom wall of the groove (14) along the thickness direction of the cover plate (10).

27. The roof assembly of any of claims 2 to 17, wherein, Along the thickness direction of the cover plate (10), the cover plate (10) is provided with a through hole, and a support part (15) is provided in the through hole. The two ends of the support part (15) arranged opposite to each other along its longitudinal direction are respectively connected to the two side hole walls of the through hole arranged opposite to each other along the length direction of the cover plate (10), and the through hole is divided into two first through holes (13) spaced apart along the width direction of the cover plate (10). Along the thickness direction of the cover plate (10), the first surface (11) of the cover plate (10) protrudes from the support part (15).

28. The top cover assembly according to any one of claims 2 to 17, characterized in that, The outer circumferential edge of the third insulating part (33) is set at an obtuse angle to the first surface (11) of the cover plate (10); and / or, The first surface (11) of the cover plate (10) is provided with a second groove (14), and the distance between the outer edge of the third insulating part (33) and the groove sidewall of the second groove (14) is a, which satisfies: 0.3mm≤a≤2mm.

29. The roof assembly of any of claims 2 to 17, wherein, It also includes a second insulating member (40), which is disposed on the side of the cover plate (10) having a second surface (12). The second insulating member (40) has a second through hole (41) corresponding to the first through hole (13). The second through hole (41) penetrates the thickness direction of the second insulating member (40). The second connecting part (22) passes through the first through hole (13) and the second through hole (41) in sequence. The circumferential outer edge of the first insulating part (31) has a first inclined structure (311). The second insulating member (40) has a second inclined structure (43) that matches the first inclined structure (311). The second inclined structure (43) abuts against the first inclined structure (311).

30. The roof assembly of claim 29, wherein, The surface of the second insulating member (40) facing away from the cover plate (10) is aligned with the surface of the first insulating part (31) facing away from the cover plate (10).

31. The roof assembly of claim 29, wherein, The second connecting portion (22) includes a third sub-part (205) and a fourth sub-part (206). Along the thickness direction of the cover plate (10), and on a plane perpendicular to the thickness direction of the cover plate (10), the orthographic projection of the fourth sub-part (206) falls within the orthographic projection range of the third sub-part (205). A second stepped surface (203) is connected between the side wall surface of the fourth sub-part (206) and the side wall surface of the third sub-part (205). The end surface of the fourth sub-part (206) away from the third sub-part (205) is a second electrical connection surface (204). The second stepped surface (203) is flush with the surface of the first insulating portion (31) away from the cover plate (10).

32. The top cover assembly according to any one of claims 2 to 17, characterized in that, Along the thickness direction of the cover plate (10), the surface of the first connecting part (21) near the cover plate (10) is the fifth surface (103). The first surface (11) of the cover plate (10) is provided with a second groove (14). The distance between the fifth surface (103) and the bottom wall of the second groove (14) is W6, which satisfies: 0.5mm≤W6≤1.2mm; or, Along the thickness direction of the cover plate (10), the cover plate (10) is provided with a through hole, and a support part (15) is provided in the through hole. The two ends of the support part (15) arranged opposite to each other along its longitudinal direction are respectively connected to the two side hole walls of the through hole arranged opposite to each other along the length direction of the cover plate (10), and the through hole is divided into two first through holes (13) spaced apart along the width direction of the cover plate (10). The side surface of the support part (15) near the first connecting part (21) is the fourth surface (151). The distance between the fifth surface (103) and the fourth surface (151) of the support part (15) is W6, which satisfies: 0.5mm≤W6≤1.2mm; and / or, Along the width direction of the cover plate (10), the maximum width of the first connecting portion (21) is W2, and the width W1 of the cover plate (10) satisfies: 20% ≤ W2 / W1 ≤ 60%; and / or, Along the width direction of the cover plate (10), the maximum width of the first connecting portion (21) is W2, satisfying: 8mm ≤ W2 ≤ 35mm; and / or, Along the width direction of the cover plate (10), the width of the cover plate (10) is W1, satisfying: W1≥20mm; and / or, The outer contour of the first connecting part (21) has at least a first outer peripheral surface (101). Along the width direction of the cover plate (10), the minimum distance between the first outer peripheral surface (101) and the edge of the cover plate (10) is W3, and the width of the cover plate (10) is W1, satisfying: 25% ≤ W3 / W1 ≤ 40%.

33. A battery cell, characterized by include: The housing (200) has an opening; An electrode assembly (300) having tabs (301) is received within the housing (200); The top cover assembly according to any one of claims 1 to 32 is disposed over the opening of the housing (200).

34. A battery, comprising: Includes the battery cell as described in claim 33.

35. An electrical device, comprising: Includes the battery as described in claim 34.

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