Battery cell

Abstract

The application provides a battery unit, which comprises a shell assembly, an electrode assembly, a switching assembly and a conducting assembly; the shell assembly comprises a shell and a shell cover, the shell comprises a bottom wall and a side wall, the electrode assembly comprises a first pole piece, a second pole piece and a diaphragm, the first pole piece comprises a first current collector and a first lug; the conducting assembly comprises a conductive nail, an inner gasket, an outer gasket and a bridge piece, a first through hole, a second through hole, a third through hole and a fourth through hole are oppositely arranged, the conductive piece passes through the first through hole, the second through hole and the third through hole and is connected with the fourth through hole of the bridge piece; the switching assembly comprises a first switching piece connected with the first lug, and the other end of the first switching piece is connected with one end of the bridge piece; the inner gasket comprises a first area, and the distance H2 between the first edge of the first area of the inner gasket and the top surface of the side wall in the thickness direction of the electrode assembly is 0.01mm-0.3mm, so that the inner side of the shell and the first switching piece are prevented from being in contact and causing short circuit.

Description

Technical Field

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

[0002] With the development of lithium-ion batteries, steel-cased batteries have gradually become a mainstream and widely used type of battery. However, the casing of steel-cased batteries carries a negative charge, so there is currently a problem with insulation short circuits in steel-cased batteries. This is mainly due to short circuits occurring when the positive electrode plate inside the cell and the positive electrode post connected to the positive electrode tab comes into contact with the casing. Currently, most structural short circuits occur on the positive electrode post side. The rigid positive electrode tab is mostly protected against short circuits by applying insulating tape, which has the following disadvantages: the insulating tape on the positive electrode tab is prone to cracking when soaked in electrolyte. After cracking, the insulating tape is prone to tearing during drops. When the rigid electrode tab is subjected to force, it moves closer to the casing, and the casing correspondingly concaves inward, causing the positive electrode to come into contact with the casing and cause a short circuit. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems in the prior art, this application provides a battery cell that avoids short circuits caused by contact between the hard tabs and the casing.

[0004] To achieve the above objectives, one embodiment of this application provides a battery cell, including a housing assembly, an electrode assembly, an adapter assembly connected to the electrode assembly, and a conductive assembly; the housing assembly includes a shell and a cover, the shell including a bottom wall and a side wall, the bottom wall and the side wall surrounding a receiving cavity for accommodating the electrode assembly and the adapter assembly; the electrode assembly includes a first electrode, a second electrode, and a separator located on the first electrode and the second electrode, the first electrode including a first current collector and a first tab protruding outward from one edge of the first current collector; the conductive assembly includes... The device comprises a conductive pin, an inner washer, an outer washer, and a bridging piece, wherein the inner washer and the outer washer are located on the inner and outer sides of the housing, respectively; the housing includes a first through hole, the inner washer includes a second through hole, the outer washer includes a third through hole, and the bridging piece includes a fourth through hole, wherein the first through hole, the second through hole, the third through hole, and the fourth through hole are arranged opposite to each other, and the conductive element passes through the first through hole, the second through hole, the third through hole, and the fourth through hole and is connected to the bridging piece; the adapter assembly includes a first adapter piece connected to the first electrode tab, and the other end of the first adapter piece is connected to one end of the bridging piece;

[0005] The inner pad includes a first region corresponding to the first adapter piece. Along the thickness direction of the electrode assembly, the distance H2 between the first edge of the first region of the inner pad and the top surface of the sidewall is 0.01mm-0.3mm.

[0006] Optionally, the first edge of the first region of the inner pad has a first protrusion protruding in the direction close to the first adapter piece, and the height of the first protrusion is 0.1-0.5mm.

[0007] Optionally, the height of the first protrusion is less than the thickness of the first adapter piece, and the difference between the height of the first protrusion and the thickness of the first adapter piece is 0.05-0.1 mm.

[0008] Optionally, the first adapter piece includes a first connection area connected to the first electrode tab, a second connection area connected to one end of the bridging piece, and a bending area connecting the first connection area and the second connection area;

[0009] The adapter assembly includes a first insulating layer covering the first connection area, the first insulating layer extending to the bending area;

[0010] Along the length of the electrode assembly, the projection of the first insulating layer on the sidewall at least partially overlaps with the projection of the first protrusion.

[0011] Optionally, the inner pad includes a second edge disposed opposite to the first edge, the second edge protruding in a direction close to the first adapter piece to form a second protrusion, the protrusion height of the second protrusion being greater than the protrusion height of the first protrusion.

[0012] Optionally, the height of the second protrusion is greater than the sum of the thicknesses of the bridging piece and the first adapter piece, and / or,

[0013] The second protrusion is recessed inward to form a first clearance groove. In the length direction of the electrode assembly, the projection of the first clearance groove and the first adapter piece on the side wall at least partially overlaps. The depth of the first clearance groove is greater than the thickness of the first adapter piece.

[0014] Optionally, a gap is left between the first insulating layer and the first protrusion along the length direction of the electrode assembly.

[0015] Optionally, the bridging piece includes a first region with the fourth through hole and a second region connected to the first adapter piece, wherein the edge of the first region and the edge of the second region are connected by a first connecting line, and the first connecting line and the edge of the first region form an angle of greater than or equal to 15°.

[0016] Optionally, the first edge of the first region of the inner pad protrudes in a direction close to the first adapter piece to form a first protrusion, and the inner pad includes a second edge disposed opposite to the first edge, the second edge protruding in a direction close to the first adapter piece to form a second protrusion;

[0017] The inner wall of the first protrusion and / or the inner wall of the second protrusion are in contact with the bridging piece.

[0018] Optionally, a second insulating layer is formed on the surface of the cover near the electrode assembly, wherein the second insulating layer and the first protrusion at least partially overlap in the thickness direction of the electrode assembly.

[0019] In the battery of this application embodiment, by setting the distance H2 between the first edge of the first region of the inner pad and the top surface of the sidewall to 0.01mm-0.3mm, the height of the first region of the inner pad is increased. Thus, even if the insulation layer is cracked, the first region of the inner pad can be isolated between the first adapter piece and the inner sidewall of the shell. When the battery is in a drop test or during normal cycling, the first adapter piece is forced to move closer to the shell, and the shell is correspondingly recessed inward. The first region of the inner pad can also prevent the first adapter piece and the shell from contacting each other and causing a short circuit.

[0020] Furthermore, by controlling the distance H2 between the first edge of the first area of ​​the inner gasket and the top surface of the sidewall to be 0.01mm-0.3mm, it is possible to prevent H2 from being too small, which would cause the distance between the first area of ​​the inner gasket and the sidewall to be too close, potentially affecting the assembly of the cover and causing interference with the welding of the cover and the sidewall of the housing.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section.

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is an exploded view of the battery cell provided in an embodiment of this application;

[0025] Figure 2A schematic cross-sectional view of the battery cell in the AT-AT direction provided in the embodiments of this application;

[0026] Figure 3 for Figure 2 Enlarged view of section A;

[0027] Figure 4 A schematic cross-sectional view of the electrode assembly of the battery cell provided in the embodiment of this application in the AF-AF direction;

[0028] Figure 5 for Figure 4 Enlarged view of section B;

[0029] Figure 6 A front view of the inner gasket of the battery cell provided in the embodiments of this application and a schematic diagram of its cross-sectional structure in the AW-AW direction and AV-AV direction;

[0030] Figure 7 The front and side views are of the bridging piece of the battery cell provided in the embodiments of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 100 - Housing assembly;

[0033] 101 - Shell; 102 - Shell cover;

[0034] 1011 - Bottom wall; 1012 - Side wall; 1013 - First flange edge; 1014 - First through hole; 1021 - Second flange edge;

[0035] 200-Electrode assembly;

[0036] 201 - First electrode; 202 - Second electrode; 203 - Diaphragm; 204 - First tab; 205 - Second tab;

[0037] 300-Adapter Component;

[0038] 301 - First adapter plate; 302 - Second adapter plate;

[0039] 3011 - First connection area; 3012 - Second connection area; 3013 - Bending area; 3014 - First insulation layer;

[0040] 400-Conducting Component;

[0041] 401 - Conductive pin; 402 - Inner washer; 403 - Outer washer; 404 - Bridging piece;

[0042] 4021 - Second through hole; 4022 - First region; 4023 - First protrusion; 4024 - Second protrusion; 4031 - Third through hole; 4041 - Fourth through hole; 4042 - First area; 4043 - Second area; 4044 - First connecting line;

[0043] 40221 - First edge; 40222 - Second edge; 40223 - First clearance groove. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0046] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0047] The terms "first," "second," and "third" (if any) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0048] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or display that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or display.

[0049] Please see Figures 1-3 One embodiment of this application provides a battery cell, including a housing assembly 100, an electrode assembly 200, a transition assembly 300 connected to the electrode assembly 200, and a conductive assembly 400. The housing assembly 100 includes a housing 101 and a cover 102. The housing 101 includes a bottom wall 1011 and a side wall 1012, which together form a cavity for accommodating the electrode assembly 200 and the transition assembly 300. In one specific example, the edge of the side wall 1012 of the housing 101 extends outward to form a first flange edge 1013. The cover 102 has a second flange edge 1021 corresponding to the first flange edge 1013. The second flange edge 1021 of the cover 102 and the first flange edge 1013 of the housing 101 are aligned and welded together to achieve an internal seal of the housing 101. In yet another specific example, the housing 101 may be made of a metal material, such as stainless steel, steel, aluminum, aluminum-plastic film, or titanium. In other embodiments, the housing 101 may be irregularly shaped such as square, trapezoidal, polygonal, columnar, or stepped.

[0050] In some embodiments, a metal plate is further connected to the outer side wall 1012 of the housing 101. This metal plate is provided with a connecting mechanism, which can be used to connect and fix with other components within the battery compartment of the terminal device. In one specific example, the connecting mechanism includes a hook portion with a through hole for connecting to a fixing post within the battery compartment. In another specific example, the connecting mechanism may also include a groove or protrusion for engaging and fixing with a fixing member within the battery compartment.

[0051] In this embodiment, the electrode assembly 200 includes a first electrode 201, a second electrode 202, and a diaphragm 203 located between the first electrode 201 and the second electrode 202. The first electrode 201 includes a first current collector and a first tab 204 protruding outward from one edge of the first current collector. The second electrode 202 includes a second current collector and a second tab 205 protruding outward from one edge of the second current collector. In one specific example, the first electrode 201 is a positive electrode and the second electrode 202 is a negative electrode; in another specific example, the first electrode 201 is a negative electrode and the second electrode 202 is a positive electrode.

[0052] In some embodiments, the electrode assembly 200 is a core formed by stacking and winding a first electrode 201, a diaphragm 203, and a second electrode 202. In other embodiments, the electrode assembly 200 is a stacked core formed by stacking a first electrode 201, a diaphragm 203, and a second electrode 202.

[0053] In some embodiments, the first current collector may be, for example, an aluminum foil, an aluminum alloy foil, or a composite current collector (e.g., an aluminum-carbon composite current collector). The thickness of the first current collector may be, for example, 6 μm-15 μm (e.g., 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm).

[0054] In one specific example, the first electrode 201 further includes a first active coating located on the first current collector, wherein the first active coating may include a positive electrode active material, such as lithium nickel cobalt manganese oxide (LiNiO2). 0.90 Co 0.05 Mn 0.05 O2 (NCM955), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM622), LiNi 0.5 Co 0.2 Mn 0.3 O2 (NCM523), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 At least one of the following: O2 (NCM111)), lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium-rich manganese-based materials, lithium cobalt oxide (LiCoO2), lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, lithium manganese silicate, spinel-type lithium manganese oxide, spinel-type lithium nickel manganese oxide, and lithium titanate.

[0055] In one specific example, the second current collector may be, for example, copper foil, copper alloy foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, or a composite current collector. In one example, the thickness of the second current collector may be, for example, 4 μm to 10 μm (e.g., 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm).

[0056] In one specific example, the second electrode 202 further includes a second active coating located on the second current collector. The second active coating may include a negative electrode active material. For example, it may include at least one of graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, spherical silicon-carbon, bulk silicon-carbon, LiAl alloy, and lithium metal. In embodiments where the negative electrode active material layer includes a silicon-carbon composite, the mass fraction of silicon content is 10%-70% (e.g., 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%).

[0057] In one specific example, the separator 203 includes a base membrane and adhesive layers located on both sides of the base membrane. In a further embodiment, a ceramic layer and an adhesive layer are sequentially formed on a first side of the base membrane, and an adhesive layer is formed on a second side. The first side surface of the base membrane is disposed opposite to the positive electrode, and the second side surface of the base membrane is disposed opposite to the negative electrode. In some embodiments, the thickness of the separator 203 is 5 μm-20 μm (e.g., 5 μm, 8 μm, 10 μm, 13 μm, 15 μm, 18 μm, or 20 μm).

[0058] In one specific example, the electrode assembly 200 also includes an electrolyte. The electrolyte comprises a lithium salt and a solvent. The solvent includes at least one of ethylene carbonate, diethyl carbonate, or fluoroethylene carbonate. In another embodiment, the electrolyte also includes a nitrile additive. The nitrile additive content is C3 based on the total mass of the electrolyte. C3 is 0.5%-8%, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, or 8%. In some embodiments, the nitrile additive includes, for example, at least one of butadionitrile, adiponitrile, and 1,3,6-hexanetrionitrile.

[0059] In this embodiment, the conductive assembly 400 is used to connect the tabs of the electrode assembly 200 to electronic components in an external device. The conductive assembly 400 includes a conductive pin 401, an inner gasket 402, an outer gasket 403, and a bridging piece 404. The inner gasket 402 and the outer gasket 403 are located on the inner and outer sides of the housing 101, respectively. The inner gasket 402 and the outer gasket 403 are used to isolate the conductive pin 401 or the bridging piece 404 from the sidewall 1012 of the housing 101. The housing 101 includes a first through hole 1014 formed on the side wall 1012 of the housing 101. The inner gasket 402 includes a second through hole 4021, the outer gasket 403 includes a third through hole 4031, and the bridging piece 404 includes a fourth through hole 4041. The first through hole 1014, the second through hole 4021, the third through hole 4031, and the fourth through hole 4041 are arranged opposite to each other, that is, the first through hole 1014, the second through hole 4021, the third through hole 4031, and the fourth through hole 4041 can be coaxially arranged. The conductive pin 401 passes through the first through hole 1014, the second through hole 4021, the third through hole 4031, and the fourth through hole 4041 and is connected to the bridging piece 404. In a specific example, the conductive nail 401 includes a shaft portion passing through a first through hole 1014, a second through hole 4021, a third through hole 4031, and a fourth through hole 4041, a first pressure plate formed from the end of the shaft portion located outside the housing 101, and a second pressure plate formed from the end of the shaft portion located inside the housing 101. The first and second pressure plates of the conductive nail 401 press and fix the inner gasket 402, the outer gasket 403, and the bridging piece 404.

[0060] In this embodiment, the adapter assembly 300 includes a first adapter piece 301 connected to the first electrode tab 204, one end of the first adapter piece 301 being connected to the first electrode tab 204, and the other end of the first adapter piece 301 being connected to one end of the bridging piece 404. In a specific example, the adapter assembly 300 further includes a second adapter piece 302 connected to the second electrode tab 205, one end of the second adapter piece 302 being connected to the second electrode tab 205, and the second adapter piece 302 being connected to the inner sidewall of the housing 101.

[0061] like Figure 7As shown, in this embodiment, the bridging piece 404 includes a first region 4042 with a fourth through hole 4041 and a second region 4043 connected to the first adapter piece 301. The first region 4042 is the area connected to the conductive pin 401. In a specific example, the first region 4042 and the second region 4043 are arranged along the width direction of the bridging piece 404, so that the conductive pin 401 and the first adapter piece 301 are spaced apart along the width direction of the electrode assembly 200 (the y-direction shown in the figure), thereby shortening the space between the electrode assembly 200 and the inner wall of the housing 101 in the length direction (the x-direction shown in the figure) and improving the overall energy density of the battery cell. In another specific example, the dimension W1 of the second region 4043 along the thickness direction (z-direction shown in the figure) of the electrode assembly 200 is larger than the corresponding dimension of the first region 4042, thereby ensuring the connection area of ​​the bridging piece 404 and the first adapter piece 301 and ensuring the connection strength of the first adapter piece 301. For example, the bridging piece 404 and the first adapter piece 301 can be connected by welding. In a further example, the width W1 of the second region 4043 is 1-5 mm, and the length L1 of the second region 4043 is 1-15 mm.

[0062] In this embodiment, the inner pad 402 includes a first region 4022 corresponding to the first adapter piece 301. That is, in the longitudinal direction of the electrode assembly 200 (the x-direction shown in the figure), the projection of the first region 4022 of the inner pad 402 onto the sidewall 1012 at least partially overlaps with the projection of the first adapter piece 301 onto the sidewall 1012. The first region 4022 of the inner pad 402 and the second region 4043 of the bridging piece 404 are correspondingly disposed. In a further example, in the thickness direction of the electrode assembly 200 (the z-direction shown in the figure), the first edge 40221 of the first region 4022 of the inner gasket 402 extends beyond the bending area of ​​the first adapter piece 301, so that the first region 4022 of the inner gasket 402 covers the bending area of ​​the first adapter piece 301. Even if the first insulating layer covering the bending area cracks to the highest point of the bending area, the first region 4022 of the inner gasket 402 can still block the bending area of ​​the first adapter piece 301 from the inner sidewall of the housing 101.

[0063] Along the thickness direction of the electrode assembly 200 (the z-direction shown in the figure), the distance H2 between the first edge 40221 of the first region 4022 of the inner pad 402 and the top surface of the sidewall 1012 is 0.01mm-0.3mm (e.g., 0.01, 0.05, 0.1, 0.12, 0.15, 0.18, 0.2, 0.25, 0.3mm).

[0064] By setting the distance H2 between the first edge 40221 of the first region 4022 of the inner gasket 402 and the top surface of the sidewall 1012 to 0.01mm-0.3mm, the height of the first region 4022 of the inner gasket 402 is increased. Thus, even if the insulation layer cracks, the first region 4022 of the inner gasket 402 can be isolated between the first adapter piece 301 and the inner sidewall of the housing 101. When the battery is in a drop test or normal cycle, the first adapter piece 301 is forced to move closer to the housing 101, and the housing 101 is correspondingly recessed inward. The first region 4022 of the inner gasket 402 can also prevent the first adapter piece 301 and the housing 101 from coming into contact with each other and causing a short circuit.

[0065] Furthermore, by controlling the distance H2 between the first edge 40221 of the first region 4022 of the inner gasket 402 and the top surface of the side wall 1012 to be 0.01mm-0.3mm, it is also possible to prevent H2 from being too small, which would cause the distance between the first region 4022 of the inner gasket 402 and the side wall 1012 to be too close, which would easily affect the assembly of the cover 102 and cause interference to the welding of the cover 102 and the side wall 1012 of the housing 101.

[0066] In one possible implementation, such as Figure 6 As shown, the first edge 40221 of the first region 4022 of the inner gasket 402 protrudes along the direction close to the first adapter piece 301 to form a first protrusion 4023. The protrusion height of the first protrusion 4023 is 0.1-0.5mm. The first region 4022 of the inner gasket 402 includes a body portion, and the first protrusion 4023 protrudes outward from the surface of the body portion close to the first adapter piece 301. By forming the first protrusion 4023, when the first insulating layer of the first adapter piece 301 cracks, the first protrusion 4023 can promptly press down on the first insulating layer, preventing the first insulating layer from folding outward and exposing the first adapter piece 301, thus avoiding contact between the first adapter piece 301 and the housing 101 and causing a short circuit.

[0067] In one specific example, the first protrusion 4023 is located on the edge of the first region 4022 of the inner gasket 402 near the cover 102. In another specific example, the first protrusion 4023 extends along the width direction of the battery cell (the y-direction shown in the figure). The dimension of the first protrusion 4023 along the width direction of the battery cell is larger than the dimension of the first adapter piece 301 along the width direction of the battery cell, so as to ensure that during drop tests or other external forces, the first adapter piece 301 and the first tab 204 can easily sway left and right and move closer to the inner wall of the housing 101. By increasing the width of the first protrusion 4023, the left and right swaying of the first adapter piece 301 and its contact with the housing 101 are prevented.

[0068] In one possible implementation, the first adapter piece 301 includes a first connection area 3011 connected to the first electrode 204, a second connection area 3012 connected to one end of the bridging piece 404, and a bending area 3013 connecting the first connection area 3011 and the second connection area 3012. In a specific example, such as Figures 3-5 As shown, the bending area 3013 is bent towards the housing 101. In another specific example, the first connection area 3011 is the solder joint area between the first tab 204 and the first adapter piece 301, and the second connection area 3012 is the solder joint area between the first adapter piece 301 and the bridging piece 404.

[0069] The adapter assembly 300 includes a first insulating layer 3014 covering the first connection area 3011. The first insulating layer 3014 extends to the bending area 3013. The function of the first insulating layer 3014 is to prevent short circuits caused by contact between the solder marks on the first connection area 3011 and the electrode assembly 200 or the housing 101. The extension of the first insulating layer 3014 to the bending area 3013 also prevents contact between the bending area 3013 of the first adapter piece 301 and the housing cover 102. In one specific embodiment, the adapter assembly 300 includes two first insulating layers 3014 covering the first connection area 3011, with the two first insulating layers 3014 located on opposite sides of the first connection area 3011. In another specific embodiment, the first insulating layer 3014 may also cover a second connection area 3012.

[0070] Along the length of the electrode assembly 200 (x-direction shown in the figure), the projection of the first insulating layer 3014 on the sidewall 1012 at least partially overlaps with the projection of the first protrusion 4023. Therefore, when the first insulating layer 3014 cracks under prolonged immersion in the electrolyte, the first protrusion 4023 can both isolate the first adapter piece 301 and the housing 101 at the crack location and also press down on the first insulating layer 3014, preventing further cracking. In a specific example, the bending radius of the bending area 3013 of the first adapter piece 301 is less than or equal to 0.5, thereby reducing the bending stress on the first insulating layer 3014 in the bending area 3013 during cyclic or drop tests and preventing cracking of the first insulating layer 3014 in the bending area 3013.

[0071] In one possible implementation, a gap of 0-0.5mm is left between the first protrusion 4023 and the first insulating layer 3014 to prevent the first protrusion 4023 and the first insulating layer 3014 from contacting each other. During the cyclic expansion of the battery cell, the first protrusion 4023 and the first insulating layer 3014 abutting each other will cause the first electrode tab 204 connected to the first adapter piece 301 to deform inward, which may easily lead to the first electrode tab 204 and the body of the electrode assembly 200 contacting each other and causing a short circuit.

[0072] In one possible implementation, the height of the first protrusion 4023 is less than the thickness of the first adapter piece 301, and the difference between the height of the first protrusion 4023 and the thickness of the first adapter piece 301 satisfies 0.05-0.1 mm. Figure 3 and Figure 5 As shown, along the length of the battery cell (x-direction shown in the figure), the first adapter piece 301 protrudes from the top surface of the first protrusion 4023 near the top surface of the electrode assembly 200. The space in which the first adapter piece protrudes from the top surface of the first protrusion 4023 near the top surface of the electrode assembly 200 can be used to accommodate the bending area 3013 of the first adapter piece 301 and the first insulating layer 3014 on the first adapter piece 301. This prevents the first adapter piece 301 from bending if the difference between the protrusion height of the first protrusion 4023 and the thickness of the first adapter piece 301 is too small when the first adapter piece 301 and the bridging piece 404 are connected. This would cause the first protrusion 4023 to easily press against the first insulating layer 3014, thereby causing the first adapter piece 301 to bend. This would result in an uneven connection interface between the first adapter piece 301 and the bridging piece 404, which could easily lead to a cold solder joint.

[0073] In one possible implementation, the inner gasket 402 includes a second edge 40222 disposed opposite to the first edge 40221. The second edge 40222 protrudes along the direction close to the first adapter piece 301 to form a second protrusion 4024, the protrusion height of the second protrusion 4024 being greater than the protrusion height of the first protrusion 4023. In a specific example, the protrusion height of the second protrusion 4024 is 0.5-1.5mm. In a specific example, the edge of the second protrusion 4024 extends beyond the edge of the first tab 204 near the bottom wall 1011 of the housing 101, thereby the second protrusion 4024 effectively protects the first adapter piece 301 and the first tab 204, preventing the second connection area 3012 of the first adapter piece 301 from contacting the second protrusion 4024 and the bottom wall 1011 of the housing 101 for short circuit. Furthermore, the height of the second protrusion 4024 is greater than that of the first protrusion 4023. By shortening the distance between the second protrusion 4024 and the body of the electrode assembly 200 or the first tab 204, the second protrusion 4024 can fix the first tab 204, the second tab 205, or the body of the electrode assembly 200, preventing the first tab 204, the second tab 205, and the electrode assembly 200 from moving arbitrarily under external force and coming into contact with the housing 101, thus preventing a short circuit. In a specific example, the distance between the second protrusion 4024 and the body of the electrode assembly 200 is 0.5-2mm, which also prevents the second protrusion 4024 from interfering with the insertion of the electrode assembly 200 into the housing.

[0074] In one possible implementation, the height of the second protrusion 4024 is greater than the sum of the thicknesses of the bridging piece 404 and the first adapter piece 301, thereby housing the bridging piece 404 and the first adapter piece 301 within the second protrusion 4024. This prevents the bridging piece 404 from wobbling and also prevents the first adapter piece 301 from shifting back and forth and contacting the bottom wall 1011 of the housing 101. In one specific example, the thickness T1 of the bridging piece 404 is 0.1-0.3 mm. In another specific example, the thickness of the first adapter piece 301 is 0.05-0.2 mm.

[0075] In one possible implementation, the second protrusion 4024 is recessed inward to form a first clearance groove 40223. Along the length direction of the electrode assembly 200 (the x-direction shown in the figure), the projections of the first clearance groove 40223 and the first adapter piece 301 onto the sidewall 1012 at least partially overlap. The depth of the first clearance groove 40223 is greater than the thickness of the first adapter piece 301. In one specific example, the first clearance groove 40223 extends along the width direction of the electrode assembly 200 (the y-direction shown in the figure), and its width is 5-18 mm. In another specific example, the depth of the first clearance groove 40223 is 0.3-1.2 mm. By providing the first clearance groove 40223, space is provided for the first adapter piece 301, which is connected to the bridging piece 404, to move back and forth, and more adjustment space is provided for the insertion of the electrode assembly 200 into the casing, thereby improving the battery manufacturing yield.

[0076] In one possible implementation, a gap is maintained between the first insulating layer 3014 and the first protrusion 4023 along the length direction of the electrode assembly 200 (the x-direction shown in the figure). This gap can be, for example, 0.2-1 mm. By controlling this gap, it is ensured that the first protrusion 4023 will not interfere with the assembly of the first adapter piece 301 and the first insulating layer 3014. This is primarily due to considerations regarding the first tab 204 of the electrode assembly 200. After the outer side of the housing 101 and the first adapter piece 301 are welded together, and the first insulating layer 3014 covers the first connection area 3011, the electrode assembly 200 is flipped into the housing. If the distance between the first insulating layer 3014 and the first protrusion 4023 is too small, the first protrusion 4023 may easily lift the first insulating layer 3014 during the process of inserting the electrode assembly 200 into the housing, causing the first insulating layer 3014 to crack prematurely. This may cause the first insulating layer 3014 to fold outward and expose the first adapter piece 301, which may lead to the first adapter piece 301 contacting the housing 101 and causing a short circuit.

[0077] In one possible implementation, the bridging piece 404 includes a first region 4042 with a fourth through hole 4041 and a second region 4043 connected to the first adapter piece 301. The edges of the first region 4042 and the second region 4043 are connected by a first connecting line 4044, which forms an angle of 15° or greater with the edge of the first region 4042. This prevents short circuits caused by contact between the bridging piece 404 and the housing 101 due to up-and-down rotation that might result from the conductive pin 401 being riveted to the bridging piece 404. In a specific example, the first region 4022 and the second region of the inner gasket 402 are also connected by a second connecting line, which forms an angle of 15° or greater with the edge of the first region 4022.

[0078] In one possible implementation, the first edge 40221 of the first region 4022 of the inner gasket 402 protrudes in a direction close to the first adapter piece 301 to form a first protrusion 4023. The inner gasket 402 includes a second edge 40222 disposed opposite to the first edge 40221. The second edge 40222 protrudes in a direction close to the first adapter piece 301 to form a second protrusion 4024. The inner sidewalls of the first protrusion 4023 and / or the inner sidewalls of the second protrusion 4024 are in contact with the bridging piece 404. By having the inner sidewalls of the first protrusion 4023 and / or the inner sidewalls of the second protrusion 4024 in contact with the bridging piece 404, it is further prevented that the vertical rotation that may be caused by the conductive pin 401 being riveted to the bridging piece 404 could easily lead to contact between the bridging piece 404 and the housing 101, resulting in a short circuit.

[0079] In one possible implementation, a second insulating layer is formed on the surface of the cover 102 near the electrode assembly 200. By providing the second insulating layer, the first adapter piece 301 is prevented from shaking up and down during drop tests, especially since the bending area 3013 of the first adapter piece 301 is bent close to the cover 102, making it more prone to contact with the housing 101 and causing a short circuit. Specifically, in the thickness direction of the electrode assembly 200 (the z-direction shown in the figure), the projection of the first adapter piece 301 onto the cover 102 lies within the second insulating layer. In a specific example, in the thickness direction of the electrode assembly 200, the second insulating layer and the first protrusion 4023 at least partially overlap to prevent the first tab 204 and the first adapter piece 301 from being extended towards the junction of the housing 101 and the cover 102 and thus contacting the housing 101 due to the force of cell expansion during battery cell cycling. By at least partially overlapping the second insulating layer and the first protrusion 4023, the connection between the housing 101 and the cover 102 is sealed off. Even if the first tab 204 and the first adapter 301 are subjected to the force of the cell expansion and extend towards the connection between the housing 101 and the cover 102, they can only contact the second insulating layer or the first protrusion 4023.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, It includes a housing assembly, an electrode assembly, a transition assembly connected to the electrode assembly, and a conductive assembly; The housing assembly includes a housing and a cover. The housing includes a bottom wall and a side wall, which enclose a receiving cavity for accommodating the electrode assembly and the adapter assembly. The electrode assembly includes a first electrode, a second electrode, and a diaphragm located between the first electrode and the second electrode. The first electrode includes a first current collector and a first tab that protrudes outward from one side edge of the first current collector. The conductive assembly includes a conductive pin, an inner washer, an outer washer, and a bridging piece, with the inner washer and the outer washer located on the inner and outer sides of the housing, respectively. The housing includes a first through hole, the inner gasket includes a second through hole, the outer gasket includes a third through hole, and the bridging piece includes a fourth through hole. The first through hole, the second through hole, the third through hole, and the fourth through hole are arranged opposite to each other. The conductive pin passes through the first through hole, the second through hole, the third through hole, and the fourth through hole and is connected to the bridging piece. The adapter assembly includes a first adapter piece connected to the first electrode tab, and the other end of the first adapter piece is connected to one end of the bridging piece; The inner pad includes a first region corresponding to the first adapter piece. Along the thickness direction of the electrode assembly, the distance H2 between the first edge of the first region of the inner pad and the top surface of the sidewall is 0.01mm-0.3mm.

2. The battery cell according to claim 1, characterized in that, The first edge of the first region of the inner pad has a first protrusion protruding in the direction close to the first adapter piece, and the height of the first protrusion is 0.1-0.5mm.

3. The battery cell according to claim 2, characterized in that, The height of the first protrusion is less than the thickness of the first adapter piece, and the difference between the height of the first protrusion and the thickness of the first adapter piece is 0.05-0.1 mm.

4. The battery cell according to claim 2, characterized in that, The first adapter includes a first connection area connected to the first electrode tab, a second connection area connected to one end of the bridging piece, and a bending area connecting the first connection area and the second connection area; The adapter assembly includes a first insulating layer covering the first connection area, the first insulating layer extending to the bending area; Along the length of the electrode assembly, the projection of the first insulating layer on the sidewall at least partially overlaps with the projection of the first protrusion.

5. The battery cell according to claim 2, characterized in that, The inner pad includes a second edge disposed opposite to the first edge, the second edge protruding in a direction close to the first adapter piece to form a second protrusion, the protrusion height of the second protrusion being greater than the protrusion height of the first protrusion.

6. The battery cell according to claim 5, characterized in that, The height of the second protrusion is greater than the sum of the thicknesses of the bridging piece and the first adapter piece, and / or, The second protrusion is recessed inward to form a first clearance groove. In the length direction of the electrode assembly, the projection of the first clearance groove and the first adapter piece on the side wall at least partially overlaps. The depth of the first clearance groove is greater than the thickness of the first adapter piece.

7. The battery cell according to claim 4, characterized in that, Along the length of the electrode assembly, there is a gap between the first insulating layer and the first protrusion.

8. The battery cell according to claim 1, characterized in that, The bridging piece includes a first region with the fourth through hole and a second region connected to the first adapter piece, wherein the edge of the first region and the edge of the second region are connected by a first connecting line, and the first connecting line and the edge of the first region form an angle of greater than or equal to 15°.

9. The battery cell according to claim 8, characterized in that, The first edge of the first region of the inner pad protrudes in a direction close to the first adapter piece to form a first protrusion, and the inner pad includes a second edge disposed opposite to the first edge, the second edge protruding in a direction close to the first adapter piece to form a second protrusion; The inner wall of the first protrusion and / or the inner wall of the second protrusion are in contact with the bridging piece.

10. The battery cell according to claim 2, characterized in that, A second insulating layer is formed on the surface of the cover near the electrode assembly, wherein the second insulating layer and the first protrusion at least partially overlap in the thickness direction of the electrode assembly.

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