Secondary battery and electric device

Abstract

The application provides a secondary battery and a power consumption device. The secondary battery comprises a shell, an electrode assembly, an electrode terminal riveted to an end wall of the shell and electrically connected to the electrode assembly, the electrode terminal comprising a penetrating portion, a first fixing portion and a second fixing portion, an insulating piece surrounding the penetrating portion, the insulating piece comprising a first insulating piece between the end wall and the first fixing portion and a second insulating piece between the end wall and the second fixing portion, a layered area being present in a compressed portion of the first insulating piece and / or the second insulating piece in a compressed state, a force applied to the compressed portion by the riveted electrode terminal comprising at least a component force in an axial direction, the direction of a line connecting a starting end and a terminal end of the layered area being an extension direction of the layered area in a radial direction of the insulating piece, and the minimum value of an angle formed between the extension direction of the layered area and the axial direction being B, 10°<B<90°. The application aims to provide a secondary battery to improve the sealing property of the secondary battery at least.

Description

Technical Field

[0001] Embodiments of this application relate to a secondary battery and an electrical device. Background Technology

[0002] In secondary batteries, an insulating component is placed between the electrode terminals and the end walls of the casing to insulate both. As the performance of secondary batteries continues to improve, the requirements for their sealing performance are also increasing. In existing secondary batteries, there is room for improvement in the sealing performance of the portion between the electrode terminals and the end walls. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this application is to provide a secondary battery and an electrical device, so as to at least improve the sealing performance of the secondary battery.

[0004] To achieve the above objectives, this application provides a secondary battery, comprising: a housing, wherein one end of the housing has an opening in its axial direction, and an end wall is provided at the other end opposite to the opening, the end wall having a mounting hole; an electrode assembly disposed within the housing; and electrode terminals riveted to the end wall, insulated from the end wall and electrically connected to the electrode assembly, the electrode terminals including a through portion passing through the mounting hole, and a first fixing portion and a second fixing portion disposed on both sides of the end wall in the axial direction; and an insulating member surrounding the through portion, the insulating member including a first insulating member disposed between the end wall and the first fixing portion, and an insulating member disposed between the end wall and the first fixing portion. A second insulating member between two fixing parts, wherein a portion of the first insulating member is compressed between the end wall and the first fixing part, and / or a portion of the second insulating member is compressed between the end wall and the second fixing part, the compressed portion of the insulating member in the compressed state has a delamination region, the force applied to the compressed portion by the riveted electrode terminal includes at least an axial component, the direction of the line connecting the start end and the end end of the delamination region along the radial direction of the insulating member is the extension direction of the delamination region, and the minimum value of the angle formed between the extension direction of the delamination region and the axial direction is B, 10° < B < 90°.

[0005] The beneficial technical effects of this application include: by controlling the minimum value B of the angle formed by the line connecting the start and end of the layered region and the axial direction to satisfy 10° < B < 90°, it is ensured that the extension direction of the layered region is not parallel to the axial direction of the force, which can prevent the extension direction of the layered region from being along the thickness direction of the compressed part. Therefore, the distribution of the layered region on the thickness can be reduced, and the increased permeability probability after the layered region extending along the thickness direction is compressed can be avoided, which can improve the sealing performance of the insulating component body, and thus improve the sealing performance of the insulating component for the secondary battery.

[0006] In some embodiments, the maximum cumulative thickness of the layered region in the corresponding compression section is d mm, the minimum thickness of the compression section in the compressed state is D mm, and d / D≤0.3.

[0007] In some embodiments, the second fixing portion is located outside the housing, the portion of the second insulating member between the end wall and the second fixing portion is a compression portion and has a compressed curved surface, the second insulating member also includes an outer edge portion surrounding the outer periphery of the second fixing portion and an inner edge portion located between the through portion and the end wall, the second insulating member includes an adhesive inlet, the adhesive inlet is located within the axial orthogonal projection range of the outer edge portion and is located on the side of the outer edge portion facing the end wall.

[0008] In some embodiments, the second fixing part is a riveting part of the electrode terminal. The electrode terminal includes a terminal body and a sealing pin. The terminal body has a hollow part on the side facing away from the electrode assembly. The sealing pin is welded to the terminal body and seals the hollow part. The terminal body is welded to the current collector at the bottom of the hollow part. The electrode terminal is electrically connected to the electrode assembly through the current collector. The material of the second insulating part is soluble polytetrafluoroethylene.

[0009] In some embodiments, there are multiple glue inlets, which are disposed on the same surface perpendicular to the axial direction and are equidistantly distributed along the circumference of the second insulating member.

[0010] In some embodiments, the first insulating member is located inside the housing, and the first fixing part is a riveting part of the electrode terminal. The contact surface of the compression part of the first insulating member and the riveting part is a compressed curved surface. In a cross-sectional view through the axis of the insulating member, the contact surface has a point that is compressed the most deeply, wherein the point does not overlap with the orthographic projection of the delamination region in the axial direction.

[0011] In some embodiments, the first fixing part is located inside the housing and is a riveting part for the electrode terminal. The compression part of the first insulating member is a compressed curved surface. The first insulating member also includes a first extension located between the through part and the end wall, and a second extension located outside the compression part of the first insulating member. The first insulating member includes an adhesive inlet, which is located on the outer side wall of the second extension away from the compression part.

[0012] In some embodiments, the first insulating member is made of soluble polytetrafluoroethylene. The secondary battery further includes a current collector connected between the electrode terminals and the electrode assembly. The insulating member also includes a third insulating member for insulating the current collector and the end wall. The third insulating member surrounds the first insulating member. The second extension overlaps with the orthogonal projection portion of the third insulating member in the axial direction. The second extension is fixed to the third insulating member in the axial direction of the housing. The axial height difference between the surface of the second extension facing the electrode assembly and the surface of the compressed portion of the first insulating member facing the electrode assembly is h mm. The thickness of the second extension is H1 mm, where h < 1.1 × H1. The axial height difference between the surface of the second extension facing the electrode assembly and the surface of the compressed portion of the first insulating member facing away from the electrode assembly is H2 mm, where H1 < 0.7 × H2.

[0013] In some embodiments, the secondary battery is a cylindrical battery, and the secondary battery also includes a cover plate that is sealed to the opening, and the casing is made of nickel-plated steel.

[0014] Embodiments of this application also provide a battery pack, including any of the aforementioned secondary batteries.

[0015] Embodiments of this application also provide an electrical device including the aforementioned battery pack. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It is worth noting that, according to industry standard practice, the components are not drawn to scale and are only used for illustrative purposes. In fact, for clarity of discussion, the dimensions of the components can be arbitrarily increased or decreased.

[0017] Figure 1 A schematic diagram is shown when the electrical device in an embodiment of this application is a vehicle.

[0018] Figure 2 A battery pack according to an embodiment of this application is shown.

[0019] Figure 3A A top view of a secondary battery according to a first embodiment of this application is shown.

[0020] Figure 3B It shows along Figure 3A A cross-sectional view of the secondary battery of the first embodiment, taken by the VV line.

[0021] Figure 3C A schematic diagram of the electrode assembly structure of a secondary battery according to a first embodiment of this application is shown.

[0022] Figure 4A It shows Figure 3B An enlarged schematic diagram of one side of the end wall of the secondary battery.

[0023] Figure 4B It shows Figure 3B A magnified view of region J in the middle area.

[0024] Figure 5 An enlarged schematic diagram of the second insulating member of the secondary battery according to the first embodiment of this application is shown.

[0025] Figure 6A A bottom perspective view of the second insulating member of the secondary battery according to the first embodiment of this application is shown.

[0026] Figure 6B It shows Figure 6A A magnified view of region S in the image.

[0027] Figure 6C A bottom view of a second insulating member according to an embodiment of this application is shown.

[0028] Figure 6D It shows along Figure 6C The cross-sectional view taken from line NN in the diagram.

[0029] Figure 6E It shows Figure 6D An enlarged view of region U in the image.

[0030] Figure 6F It shows along Figure 6C The cross-sectional view taken from line OO in the diagram.

[0031] Figure 7 This is an enlarged schematic diagram of the second insulating element according to another embodiment of this application.

[0032] Figure 8 A top perspective view of the first insulating member of the secondary battery according to the first embodiment of this application is shown.

[0033] Figure 9 A cross-sectional view of a secondary battery according to a second embodiment of this application is shown.

[0034] Figure 10A It shows Figure 9 An enlarged schematic diagram of one side of the end wall of the secondary battery.

[0035] Figure 10B It shows Figure 9 Enlarged schematic diagram of area E in the middle region.

[0036] Figure 11 An enlarged schematic diagram of the first insulating member of a secondary battery according to a second embodiment of this application is shown.

[0037] Figure 12A A top perspective view of the first insulating member of a secondary battery according to a second embodiment of this application is shown.

[0038] Figure 12B It shows Figure 12A A bottom-view perspective view of the first insulating component.

[0039] Figure 12C It shows Figure 12A A bottom view of the first insulating component.

[0040] Figure 12D It shows Figure 12ATop view of the first insulating element in the structure.

[0041] Figure 12E It shows along Figure 12D The cross-sectional view taken from line TT in the diagram.

[0042] Figure 13 This is an enlarged cross-sectional view of the first insulating element according to another embodiment of this application. Detailed Implementation

[0043] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0044] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0045] The terms “approximately,” “generally,” “substantial,” “substantial,” “about,” and “approximately” used herein are used to indicate and explain minor variations. For example, when used in conjunction with numerical values, the above terms may refer to a range of variation less than or equal to ±10% of the corresponding numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. As another embodiment, the thickness of a film or layer being “substantially uniform” may refer to the average thickness of the film or layer being less than or equal to ±10% of the standard deviation, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. The term "substantially coplanar" can refer to two surfaces that are within 50 μm along the same plane (such as within 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm along the same plane). If, for example, two components overlap or overlap within 200 μm, 150 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm, then the two components can be considered "substantially aligned." If the angle between two surfaces or components is, for example, 90° ± 10° (such as ± 5°, ± 4°, ± 3°, ± 2°, ± 1°, ± 0.5°, ± 0.1°, or ± 0.05°), then the two surfaces or components can be considered "substantially perpendicular." When used in conjunction with an event or situation, the terms "approximately," "generally," "substantially," "materially," "about," and "approximately" can refer to the exact occurrence of the event or situation as well as the very close approximation of its occurrence.

[0046] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.

[0047] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0048] Typically, a secondary battery includes an electrode assembly, a housing, a cover plate, and terminals. The housing includes an end wall and a side wall surrounding the end wall, with an opening at one end of the side wall. The electrode assembly can be assembled into the housing through the opening. The cover plate is used to close the opening of the housing to achieve a seal. The terminals pass through the end wall and are electrically connected to the electrode assembly to serve as electrode terminals of the secondary battery.

[0049] To reduce the risk of short circuits, it is necessary to insulate the terminals from the end walls and the electrode assembly from the end walls. Typically, an insulating element is sandwiched between the terminals and the end walls. This insulating element is at least partially located between the terminals and the end walls to insulate them, and extends radially towards the sidewalls of the end walls to insulate the electrode assembly from the end walls. Simultaneously, the insulating element also provides a seal between the terminals and the end walls. During the formation of the insulating element, delamination can occur. Delamination affects the sealing performance of the insulating element, and consequently, the sealing performance of the battery. To address the above technical problems, this application provides a secondary battery, a battery pack, and an electrical device.

[0050] See Figure 1 This application provides an electrical device 1000, which includes a battery pack 300. The working part of the electrical device 1000 is connected to the battery pack 300 to obtain electrical power. As an example, the electrical device 1000 is a vehicle, which 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., but are not limited thereto. The battery pack 300 is, for example, located at the bottom of the vehicle body 1001 and provides electrical power for the vehicle's operation or the operation of electrical components within the vehicle. However, in other embodiments, the electrical device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part is a unit component capable of obtaining electrical power from the battery pack 300 and performing corresponding work, such as the fan blade rotation unit of a fan, the vacuuming unit of a vacuum cleaner, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and 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. This application does not impose any special limitations on the aforementioned electrical device 1000.

[0051] See Figure 2This application also provides a battery pack 300. The battery pack 300 may include a housing 101, a cover 102, and multiple secondary batteries 100. The multiple secondary batteries 100 are placed in the housing 101 and are connected in series, parallel, or a combination of both. The cover 102 seals the housing 101 to protect the multiple secondary batteries 100. It should be noted that, in addition to the secondary batteries 100, the battery pack 300 may also include a battery thermal management system, circuit boards, etc. The battery pack 300 may be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0052] Figure 3A A top view of a secondary battery 100 according to a first embodiment of this application is shown. Figure 3B It shows along Figure 3A A cross-sectional view of the secondary battery 100 of the first embodiment, taken by the VV line. See also... Figure 3A and Figure 3B As shown, the secondary battery 100 may include a housing 10 and a cover plate 30. The housing 10 has an end wall 14 and a side wall 12 surrounding the end wall 14. The side wall 12 is located at one end opposite to the end wall 14. Figure 3B The lower end of the housing 10 has an opening, and the cover plate 30 covers the opening of the housing 10 to achieve a seal. The cover plate 30 and the housing 10 can be connected in a sealed manner using any suitable structure. In some embodiments, the cover plate 30 can be welded to the side wall 12 of the housing 10. The housing 10 can be made of various materials, such as copper, iron, aluminum, nickel-plated steel, aluminum alloy, etc. In order to prevent the housing 10 from rusting during long-term use, a rust-preventive material such as metallic nickel can also be plated on the surface of the housing 10.

[0053] The sidewall 12 surrounds the end wall 14. As long as a stable seal and electrical connection can be formed, the connection between the end wall 14 and the sidewall 12 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the sidewall 12 is not limited; it can be cylindrical or prismatic, or it can follow any other closed-loop contour that matches the end wall 14. The outer edge of the end wall 14 can be circular, and the sidewall 12 can be cylindrical, surrounding the outer edge of the end wall 14, with a circular opening at the end of the sidewall 12 facing away from the end wall 14. A cavity is formed within the housing 10 formed by the end wall 14 and the sidewall 12 to accommodate the electrode assembly 120, electrolyte, and other necessary battery components. The electrode assembly 120 is the component in the secondary battery 100 where the electrochemical reaction occurs. Specifically, the diameter of the housing 10 can be determined according to the specific size of the electrode assembly 120, such as 18mm, 21mm, 46mm, etc.

[0054] Figure 3CA schematic diagram of the electrode assembly 120 of a secondary battery 100 according to a first embodiment of this application is shown. Figure 3C As shown, the electrode assembly 120 includes a positive electrode 121, a negative electrode 123, and a separator 122, which are wound together to form a wound structure. The separator 122 is disposed between the positive electrode 121 and the negative electrode 123 to isolate the positive electrode active material and the negative electrode active material.

[0055] Specifically, the positive electrode 121 may include a positive current collector 1211 and a positive active material layer 1212 coated on a portion of the surface of the positive current collector 1211. The positive current collector 1211 has a positive uncoated region 1213 uncoated by the positive active material layer 1212. The first uncoated region 1213 is bent toward the axis of the housing 10 to form a stacked positive electrode tab 125. The negative electrode 123 includes a negative current collector 1231 and a negative active material layer 1232 coated on a portion of the surface of the negative current collector 1231. The negative current collector 1231 has a negative uncoated region 1233 uncoated by the negative active material layer, and the negative uncoated region 1233 is bent toward the axis of the housing 10 to form a stacked negative electrode tab 124. The positive electrode tab 125 and the negative electrode tab 124 are located at opposite ends of the electrode assembly 120 in the height direction of the secondary battery 100. In some embodiments, the positive electrode tab 125 is located at one end of the electrode assembly 120 facing the end wall 14, and the negative electrode tab 124 is located at one end of the electrode assembly 120 facing the cover plate 30.

[0056] Taking a lithium-ion secondary battery 100 as an example, the positive electrode current collector 1211 can be made of aluminum, and the positive electrode active material layer 1212 includes positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector 1231 can be made of copper, and the negative electrode active material layer 1232 includes negative electrode active material, which can be carbon or silicon, etc. The substrate material of the separator 122 can be polypropylene (PP) or polyethylene (PE), etc. In order to protect and insulate the battery cell, an insulating film can also be wrapped around the outside of the battery cell. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0057] See also Figure 3BAs shown, electrode terminal 40 is fixed to end wall 14 and electrically connected to electrode assembly 120. Electrode terminal 40 can also be referred to as electrode post. In this embodiment, first current collector 141 is disposed between electrode terminal 40 and electrode assembly 120, and second current collector 142 is disposed between cover plate 30 and electrode assembly 120. In some embodiments, first current collector 141 can be welded to the bottom of electrode terminal 40. Electrode terminal 40 can be electrically connected to positive electrode tab 125 of electrode assembly 120 through first current collector 141, so that electrode terminal 40 is positively charged and used as positive terminal. In some embodiments, second current collector 142 can be welded to negative electrode tab 124 of electrode assembly 120. Second current collector 142 can also be welded to side wall 12 or cover plate 30 of housing 10 in any suitable manner. Housing 10 or cover plate 30 can be electrically connected to negative electrode tab 124 of electrode assembly 120 through second current collector 142, thereby becoming negatively charged. In some embodiments, the negatively charged end wall 14 can be used as a negative terminal. It should be understood that in other embodiments, the negative electrode tab 124 may also be electrically connected to the electrode terminal 40, and the positive electrode tab 125 may be electrically connected to the housing 10 or the cover plate 30.

[0058] Figure 4A It shows Figure 3B An enlarged schematic diagram of one side of the end wall 14 of the secondary battery 100. Figure 4B It shows Figure 3B A magnified view of region J in the middle area. See also... Figure 4A and Figure 4B As shown, the end wall 14 is provided with a mounting hole 14v, through which the electrode terminal 40 passes and is fixedly connected to the end wall 14. Specifically, the electrode terminal 40 includes a through portion 44 passing through the mounting hole 14v, and a first fixing portion 41 and a second fixing portion 42. Along the axial direction A of the housing, the first fixing portion 41 and the second fixing portion 42 are disposed on both sides of the end wall 14. The first fixing portion 41 may be located on the inner side of the end wall 14 facing the electrode assembly 120, and the second fixing portion 42 may be located on the outer side of the end wall 14 facing away from the electrode assembly 120.

[0059] The insulating member 70 can be used to insulate the electrode terminal 40 from the end wall 14, and to insulate the electrode assembly 120 from the end wall 14. Specifically, the insulating member 70 may include a first insulating member 71 and a second insulating member 72. At least a portion of the first insulating member 71 is disposed between the first fixing portion 41 and the end wall 14. At least a portion of the second insulating member 72 is disposed between the second fixing portion 42 and the end wall 14.

[0060] The secondary battery 100 may further include a seal 90, which is disposed around the through portion 44 of the electrode terminal 40. The seal 90 may also be referred to as a sealing ring. At least a portion of the seal 90 is held between the first fixing portion 41 and the end wall 14. The portion of the seal 90 may also extend into the mounting hole 14v and be located between the end wall 14 and the through portion 44. The seal 90 can provide a sealing effect between the electrode terminal 40 and the end wall 14. The material of the seal 90 may be, for example, fluororubber.

[0061] According to embodiments of this application, a portion of the first insulating member 71 is compressed between the end wall 14 and the first fixing portion 41 of the electrode terminal 40, and / or a portion of the second insulating member 72 is compressed between the end wall 14 and the second fixing portion 42 of the electrode terminal 40. In some embodiments, the electrode terminal 40 and the end wall 14 are riveted together to compress portions of the first insulating member 71 and / or the second insulating member 72.

[0062] In the secondary battery 100 of the first embodiment, see Figure 4A and Figure 4B As shown, the second fixing portion 42 located outside the housing 10 is the riveting portion of the electrode terminal 40, which can be considered as externally riveted. It should be understood that although the electrode terminal 40 is externally riveted, the first fixing portion 41 and the second fixing portion 42 actually work together to compress the second insulating member 72 located between the second fixing portion 42 (riveting portion) and the end wall 14. Specifically, the second fixing portion 42 of the electrode terminal 40 may originally extend parallel to the axial direction A, then the second fixing portion 42 of the electrode terminal 40 passes through the mounting hole 14v from inside the housing 10, and then the second fixing portion 42 is folded so that the second fixing portion 42 bends toward the end wall 14. The bent second fixing portion 42 extends radially R and exceeds the mounting hole 14v, and the bent second fixing portion 42 squeezes the second insulating member 72 to compress at least a portion of the second insulating member 72 between the end wall 14 and the second fixing portion 42. By compressing at least a portion of the second insulating member 72 between the end wall 14 and the second fixing portion 42 of the electrode terminal 40, the second insulating member 72 can be fixed and serve as insulation and sealing. After bending the second fixing portion 42, at least a portion of the first insulating member 71 can be clamped between the end wall 14 and the first fixing portion 41 to serve as insulation and sealing.

[0063] In some embodiments, the insulating element 70 can be any plastic material suitable for electrical insulation, such as soluble polytetrafluoroethylene (PFA), polypropylene (PP), polybutylene terephthalate (PBT), etc. PFA material has a melting point of approximately 310°C; a melt flow index (MFR, tested according to ISO R1133) ≥9 g / 10 min, for example, including two specifications, one of 14 g / 10 min and the other of 30 g / 10 min; a yield strength of 10-20 MPa; and good thermal stability. PP material has an MFR of 8.0 g / 10 min; a melting point of approximately 164-170°C; and a yield strength of 25-40 MPa. PBT material has a melting point of approximately 225-275°C; and poorer thermal stability compared to PFA material. Comparing the three materials, PFA material has better high-temperature resistance, crack resistance, resilience, and corrosion resistance. In some embodiments, the first insulating element 71 can be referred to as the lower plastic, and the second insulating element 72 can be referred to as the lower plastic.

[0064] In some embodiments, the insulating part 70 at the riveting position is made of PFA material. In this embodiment, preferably, the second insulating part 72 is made of PFA. Compared with other plastic materials (such as PP, PPS, etc.), PFA material has a lower yield strength and better elasticity, which can provide a certain sealing performance at the interface between the insulating part 70, the electrode terminal 40, and the housing 10, while also ensuring the sealing performance of the insulating part 70 itself in the circumferential direction C. For example, PP plastic is more brittle and prone to plastic deformation than PFA material. When squeezed by the electrode terminal 40, PP material is prone to cracking, affecting the sealing performance. Therefore, the material of the second insulating part 72 squeezed by the second fixing part 42 is preferably PFA, which can increase the contact between the second insulating part 72, the end wall 14, and the electrode terminal 40, and achieve a good sealing effect.

[0065] Insulating element 70 (either the first insulating element 71 or the second insulating element 72) can be formed by injection molding, a process in which plastic is melted from particles into a fluid and then solidified. The fluid plastic material can pass through a gate. In the injection molding process of plastic materials (e.g., PFA), the shear rate of the molten plastic slurry represents the rate of velocity change between adjacent fluid layers during fluid flow. When the fluid passes through a runner or gate, the flow velocity difference between the outer and central layers is significant, creating a shearing effect, at which point the shear rate reaches a high value. Therefore, the shear rate is an important parameter describing the internal velocity gradient of the molten material flowing in the runner and cavity.

[0066] In injection molding, the phenomenon of adjacent fluid layers during fluid flow is a typical characteristic of laminar flow, where the molten plastic material flows in a laminar state. The characteristics of laminar flow are parallel flow in layers, with no lateral mixing between layers, and motion is transmitted only through shear stress. The velocity distribution of the flow layers is as follows: for the flow layer close to the mold wall, the velocity is minimum due to the adsorption of plastic molecules to the mold wall; for the central flow layer, the velocity is maximum further from the wall, forming a parabolic velocity gradient, i.e., faster in the middle and slower at the sides; for the relative sliding of adjacent flow layers, the velocity difference between layers under shear stress creates interlayer frictional resistance, hindering overall flow. Taking a cylindrical runner as an example, the radial velocity distribution R is parabolic, with the highest velocity at the center and the lowest at the wall; for mold cavities or runners with non-circular cross-sections (e.g., rectangular or irregular cavities), the flow layers still follow the "faster at the center, slower at the edges" rule, but the velocity gradient may vary depending on the cross-sectional shape.

[0067] Therefore, due to the different shear stresses and large velocity differences at the edge and center of the flow channel, stratification occurs. For example... Figure 5 As shown, the formed second insulating element 72 may have multiple layered regions 79. The layered regions 79 may manifest as gaps within the second insulating element 72. According to embodiments of this application, the layered regions 79 refer to layered structures observable by a 4K resolution testing device, such as a Phoenix Vltomelx M300 4K resolution testing device. Specific reasons for the formation of layered regions 79 may include: wall adsorption, where the flow layer adhering closely to the mold wall becomes stationary due to adsorption, forming a low-velocity boundary layer; shear stress transmission, where the high-speed movement of the central flow layer drives adjacent flow layers through shear stress, forming a gradient velocity distribution; and viscosity influence, where the greater the dynamic viscosity, the greater the interlayer shear stress, and the more pronounced the layering phenomenon. The layered regions 79 may be substantially parallel to the fluid flow direction. In actual operation, improper control of process parameters during plastic injection molding, or the selection of certain specific materials, can lead to layering after the insulating element is formed.

[0068] For the insulating component 70, factors affecting the sealing performance at the electrode terminal 40 typically include: the sealing performance of the interface between the insulating component 70 and the electrode terminal 40, and the end wall 14 during riveting, as well as the sealing performance of the material of the insulating component 70 itself. If delamination is severe, organic molecules, water molecules, etc., will penetrate into the delaminated area 79, penetrating even faster at the delamination interface, affecting the sealing performance of the insulating component 70 itself.

[0069] A portion of the second insulating member 72 is compressed due to the combined action of the first fixing portion 41 and the second fixing portion 42, resulting in a compressed portion of the second insulating member 72 between the end wall 14 and the second fixing portion 42. This compressed portion of the second insulating member 72 is called the compression portion 725. Specifically, the compression portion 725 is the area of ​​the second insulating member 72 on the end wall 14 that is compressed by the combined action of the first fixing portion 41 and the second fixing portion 42; that is, the compression portion 725 is the area on the end wall 14 where the second insulating member 72 overlaps with both the first fixing portion 41 and the second fixing portion 42 in the axial direction A. In some embodiments, the compression portion 725 is the portion of the second insulating member 72 located between the second fixing portion 42 and the end wall 14.

[0070] The force applied by the riveted electrode terminal 40 to the compression portion 725 includes a component force in the axial direction A. That is, even if the riveted electrode terminal 40 (e.g., the second fixing portion 42) applies a force to the second insulating member 72 in a direction inclined to the axial direction A, the electrode terminal 40 will still apply a component force to the second insulating member 72 in the axial direction A.

[0071] At least a portion of at least one layered region 79 exists in the compression section 725. The layered region 79 may have a starting end 79a and an ending end 79b, which are connected to form a connecting line La. The direction of the connecting line La is the extension direction of the layered region 79. The minimum value of the angle formed by the connecting line La and the axial direction A is B. The angle formed by the connecting line La and the axial direction A refers to the acute angle formed by them. In some embodiments, 10° < B < 90°, so that the connecting line La and the axial direction A are not parallel, that is, the extension direction of the layered region 79 is not parallel to the axial direction A, and therefore the extension direction of the layered region 79 is not along the thickness direction of the compression section 725. In some embodiments, the minimum value of the angle formed by the connecting line La and the axial direction A, satisfying 10° < B < 90°, can be achieved by controlling the parameters of the plastic material in the injection molding process.

[0072] Because the compression portion 725 of the second insulating member 72 will be compressed, if the extension direction of the layered region 79 in the compression portion 725 is parallel to the axial direction along the thickness direction, the probability of penetration through the insulating member body increases when such a layered region 79 is compressed. Furthermore, the larger the ratio of the thickness occupied by the gaps in such layered regions 79 to the compressed thickness, the greater the probability of penetration through the insulating member body. According to the embodiments of this application, by controlling the minimum angle B formed by the line La connecting the layering start end 79a and the end end 79b with the axial direction A to satisfy 10° < B < 90°, it is ensured that the extension direction of the layered region 79 is not parallel to the force-bearing axial direction A. This avoids the extension direction of the layered region 79 being along the thickness direction of the compression portion 725, thus reducing the distribution of layered gaps on the thickness and preventing the increased penetration probability after compression of layers extending along the thickness direction. This improves the sealing performance of the insulating member body, thereby enhancing the sealing performance of the insulating member for the secondary battery.

[0073] In some embodiments, the maximum cumulative thickness of the plurality of layered regions 79 in the compression portion 725 is d mm. The maximum cumulative thickness refers to the sum of the thicknesses of the overlapping portions of the plurality of layered regions 79 along the axial direction A. Figure 5 In the example shown, the cumulative thickness of the layered regions 79 in the compression section 725 is the sum of the thicknesses d1 and d2 of the overlapping portions of the two layered regions 79. Furthermore, the minimum thickness of the compression section 725 is D mm. In some embodiments, d / D ≤ 0.3. The more layered regions 79 distributed in the thickness direction, the more it affects the sealing performance. A ratio of d / D ≤ 0.3 between the maximum cumulative thickness of the layered regions 79 in the compression section 725 and the minimum thickness of the compression section 725 can reduce the proportion of the layered regions 79 in the thickness of the compression section 725, thus controlling and improving the sealing performance of the second insulating member 72 material itself.

[0074] Figure 6A A bottom perspective view of the second insulating member 72 of the secondary battery 100 according to the first embodiment of this application is shown. Figure 6B It shows Figure 6A A magnified view of region S in the image. Figure 6C A bottom view of the second insulating member 72 of the secondary battery 100 according to the first embodiment of this application is shown. Figure 6D It shows along Figure 6C The cross-sectional view taken from line NN in the diagram. Figure 6E It shows Figure 6D A magnified view of the central region U. Figure 6F It shows along Figure 6C The cross-sectional view taken from line OO in the diagram.

[0075] Combination Figures 4B to 6FAs shown, the second insulating member 72 may further include an outer edge 722 and an inner edge 724. The outer edge 722 is connected to the compression portion 725 and surrounds the outer periphery of the second fixing portion 42. The inner edge 724 is connected to the compression portion 725 and extends into the mounting hole 14v, located between the through portion 44 and the end wall 14.

[0076] The second insulating member 72 may also include a glue inlet 74. Since the molten plastic slurry enters the mold from the glue inlet of the mold of the second insulating member 72 during demolding, the glue inlet 74 is a structure formed on the cured second insulating member 72 by the glue inlet of the mold after demolding. In some embodiments, the glue inlet 74 is provided within the orthogonal projection range of the outer edge 722 in the axial direction A, and is located on the side of the outer edge 722 facing the end wall 14. Since the compression portion 725 is the area of ​​the second insulating member 72 subjected to extrusion pressure, if the glue inlet 74 is provided at the stressed compression portion 725, it will affect the interface seal between the compression portion 725 and the end wall 14. Therefore, the glue inlet 74 must be avoided at the stressed position of the second insulating member 72. Furthermore, since the width of the inner edge 724 extending to the mounting hole 14v is very small, it is also unsuitable for providing the glue inlet 74. By positioning the glue inlet 74 on the side of the outer edge 722 facing the end wall 14, the glue inlet 74 avoids the location where the second insulating member 72 is subjected to compressive force, and the glue inlet 74 is not visible in appearance, thus also taking into account the product's appearance. Furthermore, since the glue inlet 74 is located on the side of the second insulating member 72 facing the end wall 14, a CCD camera can be used to identify whether the second insulating member 72 is installed backwards, thereby achieving foolproof installation of the second insulating member 72.

[0077] The second insulating member 72 may have a through hole for the through portion 44 to pass through. The maximum outer diameter of the second insulating member 72 along the radial direction R is D3 mm, and the minimum diameter of the through hole (measured at the portion along the radial direction R aligned with the through portion 44) is d3 mm (see...). Figure 6DWhen there are multiple through holes, the diameter of the smallest through hole is referred to here, that is, the minimum diameter of the second insulating member 72 is d mm. In some embodiments, the value of D3-d3 ranges from 3 to 12. When the second insulating member 72 is injection molded, the longer the material path along the radial direction R, the more severe the delamination phenomenon. By controlling the difference between the maximum outer diameter and the maximum inner diameter of the second insulating member 72, the length of the material flow path along the radial direction R can be controlled to reduce the delamination region 79. At the same time, taking into account the insulation reliability of the electrode terminal 40 and the housing 10, the difference D3-d3 cannot be too small (e.g., less than 3 mm). When the number of injection ports 74 is multiple (≥2) and the difference between the maximum outer diameter D3 and the maximum inner diameter d3 of the second insulating member 72 is between 3 mm and 12 mm, the distribution of the delamination region 79 in the radial direction R and the circumferential direction C can be improved simultaneously. In some embodiments, the maximum outer diameter D3 mm of the second insulating member 72 ranges from 18 mm to 20 mm, and the maximum inner diameter d3 mm ranges from 13 mm to 15 mm.

[0078] Figure 7 This is an enlarged schematic diagram of the second insulating member 72 according to another embodiment of this application. See also Figure 7 As shown, the second fixing part 42 is the riveting part of the electrode terminal 40. The compression part 725 of the second insulating member 72 between the end wall 14 and the second fixing part 42 is squeezed by the second fixing part 42, forming a compressed curved surface. That is, a portion of the upper surface of the compression part 725 is squeezed by the second fixing part 42 to form a curved surface 72c. The portion corresponding to the curved surface 72c is compressed more deeply by the second fixing part 42 than other portions of the compression part 725. The glue inlet 74 can be located within the orthogonal projection range of the outer edge 722 in the axial direction A, and is located on the side of the outer edge 722 facing the end wall 14. In this way, the glue inlet 74 can avoid the position of the second insulating member 72 that is subjected to the compressive force, while also taking into account the product appearance.

[0079] The compression portion 725 of the second insulating member 72, in a compressed state, contacts the second fixing portion 42 at a surface that is a compressed curved surface 72C. In a cross-sectional view along the axis of the second insulating member 72, this contact surface has a point 729 where the compression is deepest (i.e., the point closest to the end wall 14). Point 729 does not overlap with the orthographic projection of the inlet 74 along axial direction A. Along axial direction A, the second insulating member 72 is most tightly sealed at point 729, where it is closest to the second fixing portion 42 and the end wall 14, thus providing the best seal. The inlet 74 and point 729 are avoided to prevent damage to the seal due to the presence of the inlet 74. The curved surface 72C where the second insulating member 72 is deepest compressed by the second fixing portion 42 extends along axial direction A and passes through point 729. The orthographic projection of point 729 does not overlap with the inlet 74 to prevent the deepest compressed area from overlapping with the inlet 74, which would affect the seal of the interface between the compression portion 725 and the end wall 14 and the second fixing portion 42.

[0080] In some embodiments, the number of glue inlets 74 is multiple, that is, the number of glue inlets 74 is at least two. Figure 6A and Figure 6C Three inlets 74 are shown as an example. Compared to an embodiment with only one inlet 74, multiple inlets 74 can reduce the path of material fluid flow in the circumferential direction C. The longer the material flow path, the faster the flow velocity of the central flow layer compared to the areas near the two side edges on the flow channel cross-section, and the more severe the delamination phenomenon of the insulating element 70 (such as the second insulating element 72 in this embodiment). By increasing the number of inlets 74, the difference in flow velocity during material flow is reduced, thereby reducing the delamination area 79 in the circumferential direction C of the second insulating element 72, thereby reducing the penetration of external substances (such as water molecules) into the interior of the secondary battery 100 through the body of the second insulating element 72, thus improving the sealing performance of the second insulating element 72 itself.

[0081] Multiple glue inlets 74 can be equidistantly distributed along the circumferential direction C of the second insulating member 72. These multiple glue inlets 74 can be located on the same surface of the second insulating member 72 perpendicular to the axial direction A, for example, on the surface of the outer edge 722 facing the end wall 14. This allows the multiple glue inlets 74 to be at the same height along the axial direction A, avoiding height differences between the inlets 74. This ensures that the material flow along the axial direction A is nearly uniform, and the material flow velocity along the circumferential direction C is also nearly uniform. Furthermore, the equidistant distribution of the multiple glue inlets 74 along the circumferential direction C prevents further increases in flow velocity differences due to varying spacing between the inlets 74. Therefore, further reducing the delamination region 79 and its length along the circumferential direction C improves the sealing performance of the second insulating member 72 itself. In addition, injecting glue from the middle position of the second insulating member 72 along the axial direction A reduces the material flow path along both the axial direction A and the radial direction R compared to injecting glue from other positions, thus improving delamination. It also reduces the steps that the material flow must traverse, as these steps create resistance and exacerbate delamination. The fact that the inlet 74 is located on the same surface of the second insulating member 72 can prevent the material injected from different inlets 74 from flowing through different steps, thus increasing the difference in flow rate and improving the delamination phenomenon.

[0082] In some embodiments, the second insulating member 72 further includes a plurality of injection ports 76, and a plurality of injection inlets 74 may be correspondingly disposed within the plurality of injection ports 76. The injection port 76 may be a recessed groove to assist in fixing the injection mold head and accurately positioning and matching the injection inlet 74. The diameter of the injection port 76 is larger than that of the injection inlet 74.

[0083] The injection port 76 can be located on the surface of the second insulator 72 perpendicular to the axial direction A, i.e., the surface of the outer edge 722 facing the end wall 14. The depth of the injection port 76 is H mm, and in some embodiments, 0.1 ≤ H ≤ 0.4. After injection molding is completed and the material has cured, due to the viscosity of the plastic fluid, stringing will occur near the injection port 74 when the second insulator 72 is pulled out of the mold. By controlling the depth H mm of the injection port 76 within the range of 0.1 mm to 0.4 mm, excess material generated due to stringing can be accommodated. Furthermore, the depth H mm of the injection port 76 should not be too large (e.g., greater than 0.4 mm) to avoid affecting the overall strength of the second insulator 72.

[0084] In some embodiments, the width of at least a portion of the glue inlet 76 near the mounting hole 14v gradually decreases along the radial direction R toward the mounting hole 14v. That is, along the radial direction R of the housing 10 away from the mounting hole 14v, the width of the aforementioned portion of the glue inlet 76 near the mounting hole 14v gradually increases. This allows for a reduction in the width of the inner end of the glue inlet 76. This prevents the inner end of the glue inlet 76 from occupying the internal area of ​​its surface (where it is in close contact with the end wall 14 during riveting pressure), thereby avoiding affecting the interface seal between the second insulator 72 and the end wall 14. In a preferred embodiment, the glue inlet 76 is a U-shaped groove with an opening facing radially outward.

[0085] In some embodiments, a helium detection groove 728 may also be provided on the second insulating member 72. After the second insulating member 72, the electrode terminal 40 and the end wall 14 are installed, the helium detection groove 728 can be used to detect whether the sealing member 90 is missing, so as to avoid the secondary battery 100 being poorly sealed due to the missing sealing member 90.

[0086] See also Figure 4A and Figure 4B The first fixing part 41, the through part 44, and the second fixing part 42 can constitute the terminal body of the electrode terminal 40. This terminal body has a hollow part 46 on its outer side facing away from the electrode assembly 120. The electrode terminal 40 is welded to the first collector plate 141 at the bottom of the hollow part 46. In some embodiments, the bottom of the hollow part 46 is recessed away from the first collector plate 141 relative to the first fixing part 41. The first collector plate 141 can have a protrusion 146 in its central region, the top surface of which can contact the bottom of the hollow part 46, and the bottom of the hollow part 46 can be welded to the protrusion 146. If the hollow part 46 is not provided, the portion of the electrode terminal 40 welded to the first collector plate 141 will have a very thick thickness. Therefore, when performing through welding from the outside of the electrode terminal 40, it will be a case of thick welding thin, making welding difficult and generating high welding temperatures. By setting a hollow section 46 and welding at the bottom of the hollow section 46, the problem of thick welding thinning when penetrating from the outside can be improved, the welding difficulty can be reduced, and the diaphragm in the electrode assembly can be burned due to excessive welding temperature.

[0087] The electrode terminal 40 may also include a sealing pin 47, which is welded to the terminal body at the opening of the hollow portion 46. The sealing pin 47 seals the hollow portion 46. Since heat is generated when welding the sealing pin 47, the material of the second insulating member 72, which is close to the welding position, needs to be heat-resistant. In addition, heat is also generated when welding the electrode terminals 40 and busbars of multiple secondary batteries 100 together. In some embodiments, the material of the second insulating member 72 is PFA. Because PFA has a high melting point and good heat resistance, it can prevent the welding heat from the surrounding environment from affecting its sealing performance. In addition, since the second insulating member 72 is located between the riveting portion (second fixing portion 42) and the end wall 14, and PFA has a certain degree of compressibility, for PFA with a certain degree of compressibility, by setting the minimum value B of the corresponding angle in the extension direction of the layered region 79 in the compression portion 725 to 10° < B < 90°, the sealing reliability of the PFA material can be improved.

[0088] Figure 8 A top perspective view of the first insulating member 71 of the secondary battery 100 according to the first embodiment of this application is shown. Figure 4A and Figure 8 As shown, at least a portion of the first insulating member 71 is disposed between the first fixing portion 41 and the end wall 14. The first insulating member 71 may extend radially outward along the end wall 14 to insulate the electrode assembly 120 from the end wall 14.

[0089] In some embodiments, the first insulating member 71 can be any plastic material suitable for electrical insulation, such as soluble polytetrafluoroethylene (PFA), polypropylene (PP), polybutylene terephthalate (PBT), etc. Preferably, in this embodiment, the material of the first insulating member 71 is PP. Compared to PFA, PP can reduce costs while providing sufficient insulation and sealing between the first fixing portion 41 of the non-riveted part and the end wall 14.

[0090] A helium detection groove 718 may be provided on the first insulating member 71, and the helium detection groove 718 is located on the surface of the first insulating member 71 facing the end wall 14. After the first insulating member 71, the second insulating member 72, the electrode terminal 40 and the end wall 14 are installed, the helium detection groove 718 can also be used to detect whether the sealing member 90 is missing, so as to avoid poor sealing of the secondary battery 100 due to the missing sealing member 90.

[0091] Figure 9 A cross-sectional view of a secondary battery 200 according to a second embodiment of this application is shown. Figure 10A It shows Figure 9 An enlarged schematic diagram of one side of the end wall 14 of the secondary battery 200. Figure 10B It shows Figure 9 Enlarged schematic diagram of area E in the middle region. Figure 9and Figures 10A to 10B The secondary battery 200 of the second embodiment shown may be the same as or similar to the secondary battery 100 of the first embodiment described above in several aspects. The following mainly describes... Figure 9 and Figures 10A to 10B The difference between the secondary battery 200 in the second embodiment shown is that...

[0092] See Figure 9 and Figures 10A to 10B As shown, at least a portion of the first insulating member 71 is disposed between the end wall 14 and the first fixing portion 41. In this embodiment, the first fixing portion 41 located inside the housing 10 is the riveting portion of the electrode terminal 40, which can be considered as internally riveted. It should be understood that although the electrode terminal 40 is internally riveted, the first fixing portion 41 and the second fixing portion 42 actually work together to compress the first insulating member 71 and / or the second insulating member 72 located between the first fixing portion 41 and the end wall 14, so as to achieve insulation and sealing.

[0093] A portion of the first insulating member 71 is compressed due to the combined action of the first fixing part 41 and the second fixing part 42, resulting in a compressed portion of the first insulating member 71 between the end wall 14 and the first fixing part 41. This compressed portion of the first insulating member 71 is called the compression portion 715. Specifically, the compression portion 715 is the area of ​​the first insulating member 71 below the end wall 14 that is compressed by the combined action of the first fixing part 41 and the second fixing part 42; that is, the compression portion 715 is the area of ​​the first insulating member 71 below the end wall 14 that overlaps with both the first fixing part 41 and the second fixing part 42 in the axial direction A. In some embodiments, the compression portion 715 is the portion of the first insulating member 71 located between the first fixing part 41 and the end wall 14.

[0094] In this embodiment, as described above, the portion of the insulating member 70 at the riveting location is made of PFA material. Preferably, in this embodiment, the first insulating member 71 is made of PFA. Compared to other plastic materials, PFA has a lower yield strength and better elasticity, providing a certain degree of sealing performance. Therefore, the first insulating member 71, which is pressed by the first fixing part 41, is preferably made of PFA, which increases the contact between the first insulating member 71, the end wall 14, and the electrode terminal 40, resulting in a good sealing effect.

[0095] The first insulating element 71 can be formed by injection molding, such as Figure 11 As shown, the first insulating element 71 formed may have multiple layered regions 79. As described above, the layered regions 79 refer to the layered structure that can be observed by a 4K resolution testing device, such as the Phoenix Vltomelx M300 4K resolution testing device.

[0096] The compressed portion 715, in a compressed state, has a layered region 79. The starting end 79a and the ending end 79b of the layered region 79 are connected to form a connecting line La. The minimum angle formed by the connecting line La and the axial direction A is B. In some embodiments, 10° < B < 90°, such that the connecting line La is not parallel to the axial direction A, and the extension direction of the layered region 79 is not along the thickness direction of the compressed portion 715. Similarly, by controlling the extension direction of the layered region 79 to be non-parallel to the force-bearing axial direction A, the extension direction of the layered region 79 can be prevented from being along the thickness direction of the compressed portion 715. Therefore, the distribution of layer gaps along the thickness can be reduced, and the increased permeability probability after compression of layers extending along the thickness direction can be avoided, thus improving the sealing performance of the insulating body.

[0097] In this embodiment, the maximum cumulative thickness of the multiple layered regions 79 in the compression section 715 is d mm, and the minimum thickness of the compression section 725 is D mm. In some embodiments, d / D ≤ 0.3 to reduce the proportion of the layered regions 79 in the thickness of the compression section 715, thereby controlling and improving the sealing performance of the first insulating member 71 material itself.

[0098] Figure 12A A top perspective view of the first insulating member 71 of a secondary battery 200 according to a second embodiment of this application is shown. Figure 12B It shows Figure 12A A bottom-view perspective view of the first insulating component 71. Figure 12C It shows Figure 12A A bottom view of the first insulating element 71. Figure 12D It shows Figure 12A Top view of the first insulating element 71. Figure 12E It shows along Figure 12D The cross-sectional view taken from line TT in the diagram.

[0099] Combination Figures 10A to 12E As shown, the first insulating member 71 may further include a first extension 714 and a second extension 712. The first extension 714 extends into the mounting hole 14v and is located between the through portion 44 of the electrode terminal 40 and the end wall 14. The second extension 712 is located outside the compression portion 715. The first extension 714 and the second extension 712 can be connected to the compression portion 715 respectively. The first insulating member 71 has a first extension 714 extending into the mounting hole 14v, and the first insulating member 71 can also provide a seal between the through portion 44 of the electrode terminal 40 and the end wall 14.

[0100] The first insulating member 71 may include a sprue 74. During injection molding of the first insulating member 71, molten plastic slurry enters the mold through the sprue of the mold for the first insulating member 71. Therefore, the sprue 74 is a structure formed on the cured first insulating member 71 after demolding. The sprue 74 may be located on the outer side wall of the second extension 712, radially away from the compression portion 715. In this embodiment, the first insulating member 71 includes a sprue 74. Since the delamination phenomenon is more severe near the sprue 74, by placing the sprue 74 on the outer side wall of the second extension 712, the compression portion 715 can be located as far away from the sprue 74 as possible, which can avoid the existence of too many delamination areas 79 in the compression portion 715 and reduce the sealing performance of the compression portion 715.

[0101] In some embodiments, the maximum outer diameter of the first insulating member 71 along the radial direction R is D4 mm. The first insulating member 71 may have a through hole through which the through portion 44 passes. The minimum diameter of the through hole (measured at the portion of the through hole aligned with the through portion 44 along the radial direction R) is d4 mm. When there are multiple through holes, the diameter of the smallest through hole is referred to here, i.e., the minimum diameter of the first insulating member 71 is d4 mm. The difference between D4 and d4 ranges from 3 to 12. By controlling the difference between the maximum outer diameter D4 and the maximum inner diameter d4 of the first insulating member 71, the length of the material flow path along the radial direction R can be controlled, thereby reducing the delamination region 79 while ensuring the insulation reliability of the electrode terminal 40 and the housing 10. In some embodiments, the maximum outer diameter D4 mm of the first insulating member 71 ranges from 18 mm to 22 mm, and the maximum inner diameter d4 mm ranges from 9 mm to 12 mm.

[0102] In some embodiments, a plurality of helium detection grooves 718 may be provided on the first insulating member 71. After the first insulating member 71, the electrode terminal 40 and the end wall 14 are installed, the helium detection grooves 718 can be used to detect whether the sealing member 90 is missing, so as to avoid the secondary battery 100 being poorly sealed due to the missing sealing member 90.

[0103] Figure 13 This is an enlarged cross-sectional view of the first insulating member 71 according to another embodiment of this application. See also Figure 13As shown, the first fixing part 41 is the riveting part of the electrode terminal 40. The compression part 715 of the first insulating member 71 between the end wall 14 and the first fixing part 41 is squeezed by the first insulating member 71, forming a compressed curved surface 71c. That is, a portion of the lower surface of the compression part 715 is squeezed by the first fixing part 41 to form the curved surface 71c. The portion corresponding to the curved surface 71c is compressed more deeply by the first fixing part 41 than other portions of the compression part 715. In such an embodiment, the glue inlet 74 can be located on the outer wall of the second extension 712 of the first insulating member 71, and the compression part 715 is as far away from the glue inlet 74 as possible to avoid excessive delamination areas 79 in the compression part 715, which would reduce the sealing performance of the compression part 715.

[0104] The contact surface between the compression section 715 and the first fixing section 41 is a compressed curved surface 71c. In a cross-sectional view passing through the axis of the first insulating member 71, this contact surface has a point 719 where the compression is deepest (i.e., the point closest to the end wall 14). Along the axial direction A, the first insulating member 71 is most tightly connected to the first fixing section 41 and the end wall 14 at point 719, resulting in the best sealing performance. The portion of the curved surface 71c where the first insulating member 71 is deepest compressed by the first fixing section 41 extends along the axial direction A and passes through point 719. Point 719 does not overlap with the orthographic projection of the layered region 79 in the compression section 715 along the axial direction A. The point 719, where the curved surface 71c is deepest compressed, is the stress area and the location with the largest compression ratio. At this location, the compression section 715 has the best sealing performance along the axial direction. The point 719, where the compression is deepest, does not overlap with the layered region 79 in the compression section 715 along the axial direction A, allowing the layered region 79 to avoid the area with the largest compression ratio, thereby increasing the sealing performance of the compression section 715. In this embodiment, the first insulating member 71 at the riveting position is made of PFA because PFA has low yield strength and better elasticity.

[0105] It can provide a certain degree of sealing performance. The insulating member 70 may also include a third insulating member 73 for insulating the first collector plate 141 and the end wall 14. The third insulating member 73 may surround the first insulating member 71. The third insulating member 73 may be annular in shape. The second extension 712 of the first insulating member 71 overlaps with the orthographic projection of the third insulating member 73 in the axial direction A. A portion of the third insulating member 73 may be located between the second extension 712 of the first insulating member 71 and the end wall 14. The second extension 712 is fixed to the third insulating member 73 in the axial direction A, and the inner ring of the third insulating member 73, radially R, near the mounting hole, rests on the second extension 712 to limit the displacement of the third insulating member 73 in the axial direction A. The third insulating member 73 and the second extension 712 may also have their radial movement limited by appropriate limiting structures.

[0106] See Figures 10A to 11The lower surface 712b of the second extension 712 faces the electrode assembly 120. The height difference between the lower surface 712b of the second extension 712 and the lower surface 715b of the compression portion 715 in the axial direction A is h mm (see, for example, see...). Figure 11 The thickness of the second extension 712 is H1 mm. The thickness H1 can be the maximum thickness of the second extension 712. In some embodiments, h < 1.1 × H1. This avoids an excessively large height difference h. If the height difference h is too large, the difference in flow velocity between different layers will increase when the fluid passes through the step formed by the height difference h during injection molding, resulting in more delamination areas and affecting the sealing performance of the riveting position of the first insulating member 71. Therefore, controlling the height difference h and reducing it to less than 1.1 × H1 allows for both securing the first insulating member 71 and ensuring its sealing performance.

[0107] The height difference in the axial direction A between the lower surface 712b of the second extension 712 and the upper surface 715a of the compression portion 715 is H2 mm. In some embodiments, H1 < 0.7 × H2. This range of values ​​for H1 and H2 allows the difference between H1 and H2 to be large enough to reserve space to accommodate and overlap the third insulating member 73. In some embodiments, the third insulating member 73 may be made of PP material to reduce costs. In one example, h = 0.45, H1 = 0.5, and H2 = 0.95.

[0108] See also Figure 10A and Figure 10B In this embodiment, the electrode terminal 40 also has a hollow portion 46. The electrode terminal 40 is welded to the first collector plate 141 at the bottom of the hollow portion 46. In this embodiment, the first collector plate 141 may have a protrusion 146 in its central region, the top surface of the protrusion 146 may contact the bottom of the hollow portion 46, and the bottom of the hollow portion 46 may be welded to the protrusion 146. By welding at the bottom of the hollow portion 46, the situation of thick welding thinner than thick welding when penetrating from the outside can be improved, the welding difficulty can be reduced, and the diaphragm in the electrode assembly can be burned due to excessive welding temperature.

[0109] Additionally, the sealing pin 47 is welded to the opening of the hollow portion 46, forming a molten pool 49 to seal the hollow portion 46. Since welding generates heat, the material of the second insulating member 72, which is close to the welding position, needs to be heat-resistant. Furthermore, heat is also generated when welding the electrode terminals 40 and busbars of the multiple secondary batteries 100 together. In this embodiment, the second insulating member 72 is made of PFA. PFA has a high melting point and excellent heat resistance, preventing the welding heat from the surrounding environment from affecting its sealing performance.

[0110] Furthermore, according to embodiments of this application, the casing 10 is made of nickel-plated steel, and the surface of the nickel-plated steel contains a nickel coating. The nickel coating is mainly used to prevent the electrolyte from corroding the nickel-plated steel. Using nickel-plated steel as the casing of the cylindrical battery requires higher sealing performance. If the sealing is poor, water will enter the cylindrical battery and react with the electrolyte to produce hydrogen ions. These hydrogen ions will react with the nickel coating of the nickel-plated steel, corroding the casing 10 and generating nickel ions. These nickel ions will then integrate into / enter the electrode assembly 120, generating nickel metal, which may cause a short circuit between the positive electrode 121 and the negative electrode 123 of the electrode assembly 120, affecting the safety of the cylindrical battery. Embodiments of this application, by enhancing the sealing performance of the insulating component 70 itself and further improving the sealing performance of the interface between the insulating component 70 and the electrode terminals 40 and end walls 14, prevent water molecules from seeping into the casing 10 from the electrode terminals 40, thus avoiding the aforementioned technical problems and improving the safety of the secondary battery 100.

[0111] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A secondary battery, characterized in that, include: A housing having an opening at one axial end and an end wall at the opposite end, the end wall having a mounting hole; Electrode assembly, disposed within the housing; An electrode terminal is riveted to the end wall, is insulated from the end wall and electrically connected to the electrode assembly. The electrode terminal includes a through portion passing through the mounting hole, and a first fixing portion and a second fixing portion disposed on both sides of the end wall in the axial direction. An insulating member surrounds the through portion, the insulating member comprising a first insulating member disposed between the end wall and the first fixing portion and a second insulating member disposed between the end wall and the second fixing portion, wherein a portion of the first insulating member is compressed between the end wall and the first fixing portion, and / or a portion of the second insulating member is compressed between the end wall and the second fixing portion. The compressed portion of the insulating member in a compressed state has a layered region. The force applied to the compressed portion by the riveted electrode terminal includes at least a component force in the axial direction. Along the radial direction of the insulating member, the direction of the line connecting the start end and the end end of the layered region is the extension direction of the layered region. The minimum value of the angle formed between the extension direction of the layered region and the axial direction is B, where 10° < B < 90°.

2. The secondary battery according to claim 1, characterized in that, The maximum cumulative thickness of the layered region in the corresponding compression section is d mm, and the minimum thickness of the compression section in the compressed state is D mm, where d / D ≤ 0.

3.

3. The secondary battery according to claim 2, characterized in that, The second fixing part is located outside the housing, and the compression part of the second insulating member has a compressed curved surface. The second insulating member further includes an outer edge portion surrounding the outer periphery of the second fixing portion, and an inner edge portion located between the through portion and the end wall. The second insulating member includes an adhesive inlet located within the orthogonal projection range of the outer edge in the axial direction and on the side of the outer edge facing the end wall.

4. The secondary battery according to claim 3, characterized in that, The second fixing part is the riveting part of the electrode terminal. The electrode terminal includes a terminal body and a sealing pin. The terminal body has a hollow portion on the side facing away from the electrode assembly. The sealing pin is welded to the terminal body and seals the hollow portion. The terminal body is welded to a current collector at the bottom of the hollow portion. The electrode terminal is electrically connected to the electrode assembly through the current collector. The second insulating component is made of soluble polytetrafluoroethylene.

5. The secondary battery according to claim 4, characterized in that, The number of glue inlets is multiple, and the multiple glue inlets are arranged on the same surface perpendicular to the axial direction and are equidistantly distributed along the circumference of the second insulating member.

6. The secondary battery according to claim 1, characterized in that, The first insulating member is located inside the housing, and the first fixing part is the riveting part of the electrode terminal. The contact surface where the compression portion of the first insulating member contacts the riveting portion is a compressed curved surface. In a cross-sectional view passing through the axis of the insulating member, the contact surface has a point where it is most deeply compressed, wherein the point does not overlap with the orthographic projection of the layered region on the axial direction.

7. The secondary battery according to claim 2, characterized in that, The first fixing part is located inside the housing and serves as the riveting part for the electrode terminal; the compression part of the first insulating member has a compressed curved surface. The first insulating member further includes a first extension located between the through portion and the end wall, and a second extension located outside the compression portion of the first insulating member. The first insulating member includes an adhesive inlet located on the outer wall of the second extension away from the compression portion.

8. The secondary battery according to claim 7, characterized in that, The first insulating component is made of soluble polytetrafluoroethylene. The secondary battery further includes a current collector connected between the electrode terminals and the electrode assembly. The insulating member further includes a third insulating member for insulating the current collector and the end wall. The third insulating member surrounds the first insulating member. The second extension overlaps with the orthographic projection of the third insulating member in the axial direction, and the second extension is fixed to the third insulating member in the axial direction. The height difference in the axial direction between the surface of the second extension facing the electrode assembly and the surface of the compression portion of the first insulating member facing the electrode assembly is h mm, and the thickness of the second extension is H1 mm, where h < 1.1 × H1; The height difference in the axial direction between the surface of the second extension facing the electrode assembly and the surface of the compression portion of the first insulating member facing away from the electrode assembly is H2 mm, where H1 < 0.7 × H2.

9. The secondary battery according to any one of claims 1-8, characterized in that, The secondary battery is a cylindrical battery. The secondary battery also includes a cover plate, which is sealed and installed at the opening, and the casing is made of nickel-plated steel.

10. An electrical appliance, characterized in that, Includes the secondary battery as described in any one of claims 1 to 9.

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