Secondary battery and battery pack

Abstract

The utility model provides a kind of secondary battery and battery pack, the secondary battery includes: shell, electrode assembly, pole, first insulating part and first sealing layer, shell includes end wall and side wall, end wall is provided with pole hole;Electrode assembly is set to the inside of shell;Pole is fixed to end wall and is electrically connected with electrode assembly;Pole includes cylindrical portion and respectively connecting first limiting portion, second limiting portion in the both ends of cylindrical portion, cylindrical portion penetrates pole hole, first limiting portion is located in the inside of shell, and second limiting portion is located in the outside of shell;First insulating part is set around the outer periphery of cylindrical portion, and at least part is clamped between first limiting portion and end wall;First sealing layer and the surface of first insulating part side towards end wall;The projection of first insulating part, first sealing layer, first limiting portion and end wall in the thickness direction of end wall at least partially mutually coincides.The utility model can improve the technical problem that the sealing performance between pole and shell in secondary battery is not good.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a secondary battery and battery pack. Background Technology

[0002] In the manufacturing process of secondary batteries, the sealing performance between the terminals and the casing plays a crucial role in the battery's lifespan and safety. As the performance of secondary batteries continues to improve, the requirements for their sealing performance are also becoming increasingly stringent.

[0003] However, the current terminal sealing structure of secondary batteries on the market has poor sealing performance, which can easily lead to many safety problems, such as leakage and short circuits, thus failing to meet the sealing requirements of high-performance secondary batteries. Utility Model Content

[0004] This invention provides a secondary battery to improve the technical problem of poor sealing performance between the terminals and the casing in existing secondary batteries.

[0005] This utility model provides a secondary battery, which includes: a shell, an electrode assembly, a terminal post, a first insulating member, and a first sealing layer. The shell includes an end wall and a side wall surrounding the end wall, and the end wall is provided with a terminal post hole. The electrode assembly is disposed inside the shell. The terminal post is fixed to the end wall and electrically connected to the electrode assembly. The terminal post includes a columnar portion and a first limiting portion and a second limiting portion respectively connected to both ends of the columnar portion. The columnar portion passes through the terminal post hole. The first limiting portion is located inside the shell and extends from the columnar portion to the outer periphery of the end wall. The second limiting portion is located outside the shell and extends from the columnar portion to the outer periphery of the end wall. The first insulating member is disposed around the outer periphery of the columnar portion and is at least partially sandwiched between the first limiting portion and the end wall. The first sealing layer is disposed around the outer periphery of the columnar portion and is located on the surface of the first insulating member facing the end wall. The projections of the first insulating member, the first sealing layer, the first limiting portion, and the end wall in the thickness direction of the end wall at least partially overlap each other.

[0006] In one embodiment of the present invention, a first groove is provided on the surface of the first insulating member facing the end wall, and a first sealing layer is disposed in the first groove.

[0007] In one embodiment of the present invention, the surface of the first insulating member facing the end wall includes a flat area and a recessed area. The flat area abuts against the end wall, and the recessed area is recessed relative to the flat area facing the electrode assembly to form a first groove.

[0008] In one embodiment of the present invention, the surface of the first insulating member facing the end wall includes a first annular boss and a second annular boss. The first annular boss is disposed around the outer periphery of the second annular boss, and the first annular boss and the second annular boss surround to form a first groove.

[0009] In one embodiment of the present invention, a second sealing layer is provided on the side of the first insulating member away from the end wall. The second sealing layer is disposed around the outer periphery of the columnar portion, and the projections of the second sealing layer, the first sealing layer and the first limiting portion in the thickness direction of the end wall at least partially overlap each other. The second sealing layer is an asphalt adhesive layer formed by a coating process or an asphalt adhesive layer formed by a spraying process.

[0010] In one embodiment of this utility model, a second groove is provided on the surface of the first insulating member away from the end wall, a second sealing layer is disposed in the second groove, and the outer edge of the first limiting part is pressed against the second sealing layer; and the thickness of the second sealing layer is less than the depth of the second groove; wherein, along the radial direction of the columnar part, the distance between the outer edge of the second groove and the outer edge of the first limiting part is W1, 0.5mm≤W1≤10mm; the depth of the first groove is T1, and 0.03mm≤T1≤0.3mm; the depth of the second groove is T2, and 0.03mm≤T2≤0.3mm.

[0011] In one embodiment of the present invention, when the material of the first insulating element is polypropylene, its surface roughness Rz is 40-120 μm; when the material of the first insulating element is perfluoroalkoxy resin, its surface roughness Rz is 10-60 μm.

[0012] In one embodiment of the present invention, the first limiting part is a riveted flange, the first insulating member deforms under the riveting pressure and forms a first recess, and the first limiting part is at least partially filled in the first recess.

[0013] In one embodiment of the present invention, the first sealing layer is an asphalt adhesive layer formed by a coating process, or the first sealing layer is an asphalt adhesive layer formed by a spraying process.

[0014] In one embodiment of the present invention, the secondary battery further includes a sealing member, which is disposed around the columnar portion and located between the second limiting portion and the end wall.

[0015] This utility model also provides a battery pack, which includes the secondary battery in any of the above embodiments. The beneficial effects of this utility model are as follows: The secondary battery proposed by this utility model has a first sealing layer disposed on the surface of the first insulating member facing the end wall, and the projections of the first insulating member, the first sealing layer, the first limiting part, and the end wall in the thickness direction of the end wall at least partially overlap. This structural design allows the first insulating member located in the clamping area between the first limiting part and the end wall to not only maintain its original insulation function but also cooperate with the first sealing layer to form an additional sealing structure between the end wall and the first insulating member. Thus, based on the original sealing structure between the electrode and the shell, a sealing structure formed by the cooperation of the first insulating member and the first sealing layer can be superimposed, thereby forming a double-layer sealing structure between the electrode and the end wall, which helps to improve the sealing performance between the electrode and the shell and improves the technical problem of poor sealing performance between the electrode and the shell in existing secondary batteries. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] In the attached diagram:

[0018] Figure 1 This is a cross-sectional view of the overall structure of a secondary battery provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the electrode assembly in a secondary battery provided in one embodiment of the present invention;

[0020] Figure 3 for Figure 1 A magnified view of a portion of region A in the middle;

[0021] Figure 4 This is a partial schematic diagram showing the location of the first sealing layer in a secondary battery according to one embodiment of the present invention;

[0022] Figure 5 for Figure 4 A cross-sectional view of the overall structure of the first insulating component in the embodiment shown;

[0023] Figure 6 for Figure 5 A magnified view of a portion of region B in the middle;

[0024] Figure 7This is a partial schematic diagram of the installation position between the first insulating member and the electrode post and end wall in a secondary battery provided in another embodiment of the present invention;

[0025] Figure 8 for Figure 7 A partial schematic diagram of the location of the first sealing layer in the illustrated embodiment;

[0026] Figure 9 for Figure 7 A cross-sectional view of the overall structure of the first insulating component in the embodiment shown;

[0027] Figure 10 for Figure 9 A magnified view of a portion of region C in the middle;

[0028] Figure 11 This is a schematic diagram of a secondary battery provided in one embodiment of the present invention, in which a first sealing layer and a second sealing layer are simultaneously provided;

[0029] Figure 12 for Figure 11 A partially enlarged schematic diagram showing the locations of the first and second sealing layers in the embodiment shown;

[0030] Figure 13 for Figure 11 The diagram shown illustrates the structure of the first insulating element having a first groove and a second groove in the embodiment shown.

[0031] Figure 14 for Figure 11 A partially enlarged view of the position of the second sealing layer relative to the first limiting part in the embodiment shown;

[0032] Figure 15 This is a schematic diagram of a secondary battery in another embodiment of the present invention, in which a first sealing layer and a second sealing layer are simultaneously provided;

[0033] Figure 16 for Figure 15 A partially enlarged schematic diagram showing the locations of the first and second sealing layers in the embodiment shown;

[0034] Figure 17 This is a partial schematic diagram of a riveted flange structure for the second limiting part in a secondary battery provided in another embodiment of the present invention;

[0035] Figure 18 This is a partially enlarged view of a third sealing layer structure provided on the side of the second insulating member facing the second limiting part in one embodiment of the present invention;

[0036] Figure 19 This is a partially enlarged view of a third sealing layer structure provided on both the side of the second insulating member facing the second limiting part and the side facing the end wall in one embodiment of the present invention;

[0037] Figure 20 This is a partially enlarged view of a third sealing layer structure provided on the side of the second insulating member facing the end wall in one embodiment of the present invention;

[0038] Figure 21 This is a schematic diagram of the contact structure between the first limiting part and the first insulating member in one embodiment of the present invention;

[0039] Figure 22 for Figure 21 A magnified view of a portion of region D in the middle;

[0040] Figure 23 This is a schematic diagram of the contact structure between the first limiting part, the first insulating member, and the second sealing layer in one embodiment of the present invention;

[0041] Figure 24 for Figure 23 A magnified view of a portion of region E in the middle;

[0042] Figure 25 This is a schematic diagram of the structure of a battery pack provided in one embodiment of the present invention.

[0043] The attached figures are labeled as follows:

[0044] 100. Secondary battery; 110. Casing; 111. End wall; 1111. Terminal hole; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. Positive electrode; 1211. Positive current collector; 1212. First coated area; 1213. First uncoated area; 122. Separator; 123. Negative electrode; 1231. Negative current collector; 1232. Second coated area; 1233. Second uncoated area; 124. Negative electrode tab; 125. Positive electrode tab; 130. Cover plate; 140. Terminal post; 141. First limiting part; 142. Columnar part; 143. Second limiting part Position; 150, First insulating element; 1531, First groove; 15311, Flat area; 15312, Recessed area; 15313, First annular boss; 15314, Second annular boss; 15315, Third annular boss; 15316, Fourth annular boss; 1532, Second groove; 160, Sealing element; 171, First sealing layer; 172, Second sealing layer; 173, Third sealing layer; 180, Second insulating element; 191, First recess; 192, Second recess; 200, Battery pack; 210, Housing; 211, First housing section; 212, Second housing section. Detailed Implementation

[0045] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0046] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0047] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0048] Please see Figures 1 to 25 This utility model provides a secondary battery 100 and a battery pack 200. The secondary battery 100 has a first sealing layer 171 provided on the surface of the first insulating member 150 facing the end wall 111, and the projections of the first insulating member 150, the first sealing layer 171, the first limiting part 141 and the end wall 111 in the thickness direction of the end wall 111 at least partially overlap. This allows the first insulating member 150 located in the clamping area between the first limiting part 141 and the end wall 111 to not only maintain its original insulation function, but also cooperate with the first sealing layer 171 to form an additional sealing structure between the end wall 111 and the first insulating member 150. This helps to improve the sealing performance between the terminal post 140 and the shell 110, and improves the technical problem of poor sealing performance between the terminal post 140 and the shell 110 in the existing secondary battery 100.

[0049] Please see Figure 1 and Figure 3 In this embodiment, the secondary battery 100 includes a housing 110, an electrode assembly 120, a terminal post 140, a first insulating element 150, and a first sealing layer 171.

[0050] Please see Figure 1The housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the side wall 112 is not limited; it can be cylindrical or prismatic, or it can follow any other closed-loop contour that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical, surrounding the outer edge of the end wall 111, with a circular opening 113 formed at the end of the side wall 112 facing away from the end wall 111. A receiving cavity is formed within the housing 110 formed by the end wall 111 and the side wall 112 to accommodate the electrode assembly 120, electrolyte, and other necessary battery components. Specifically, the diameter of the housing 110 can be determined according to the specific size of the electrode assembly 120, such as 18mm, 21mm, or 46mm. The shell 110 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the shell 110 from rusting during long-term use, a layer of anti-rust material such as metallic nickel can be plated on the surface of the shell 110.

[0051] Please see Figure 1 and Figure 2 The electrode assembly 120 is disposed inside the housing 110 and is a component in the secondary battery 100 where electrochemical reactions occur. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 includes an electrode sheet and a separator 122, which are wound to form a wound structure. Specifically, in this embodiment, the electrode assembly 120 includes a positive electrode sheet 121, a separator 122, and a negative electrode sheet 123 wound axially around the housing 110.

[0052] The positive electrode 121 includes a positive current collector 1211 and a positive active material layer coated on the positive current collector 1211. A first coated area 1212 coated with the positive active material layer and a first uncoated area 1213 uncoated with the positive active material layer are formed on the positive current collector 1211. The first coated area 1212 and the first uncoated area 1213 are arranged along the axial direction of the housing 110. The first uncoated area 1213 extends to one end of the secondary battery 100 in the height direction to the outside of the separator 122 and is bent towards the axis of the housing 110 to form a stacked positive electrode tab 125.

[0053] The negative electrode 123 includes a negative current collector 1231 and a negative active material layer coated on the negative current collector 1231. A second coated area 1232 coated with the negative active material layer and a second uncoated area 1233 uncoated with the negative active material layer are formed on the negative current collector 1231. The second coated area 1232 and the second uncoated area 1233 are arranged along the axial direction of the housing 110. The second uncoated area 1233 extends to the other end of the secondary battery 100 in the height direction to the outside of the separator 122 and is bent towards the axis of the housing 110 to form a stacked negative electrode tab 124.

[0054] A separator 122 is disposed between the positive electrode 121 and the negative electrode 123 to isolate the positive and negative active material layers. Taking a lithium-ion secondary battery 100 as an example, the positive current collector 1211 can be made of aluminum, and the positive active material layer includes positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative current collector 1231 can be made of copper, and the negative active material layer includes negative active material, which can be carbon or silicon, etc. The substrate material of the separator 122 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the electrode assembly 120, an insulating film can also be wrapped around the electrode assembly 120. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0055] Please see Figure 1 and Figure 2 Furthermore, in this invention, the positive electrode tab 125 faces the end wall 111 or the opening 113, while the negative electrode tab 124 faces the other end of the housing 110. In this embodiment, the positive electrode tab 125 faces the end wall 111 and is electrically connected to the terminal post 140, making the terminal post 140 positively charged. The negative electrode tab 124 faces the opening 113, and the housing 110 is electrically connected to the negative electrode tab 124, thus becoming negatively charged. However, in another embodiment, the negative electrode tab 124 can be connected to the terminal post 140, and the positive electrode tab 125 can be connected to the housing 110.

[0056] Please see Figure 1 The secondary battery 100 also includes a cover plate 130, which is sealed and installed in the opening 113. The outer edge shape of the cover plate 130 corresponds to the shape of the opening 113 and is connected to the side wall 112 to seal the opening 113. The installation method of the cover plate 130 includes, but is not limited to, mechanical sealing or welding sealing. In this embodiment, the cover plate 130 is sealed and plugged in the opening 113 by means of mechanical sealing.

[0057] Please see Figure 3 The end wall 111 is provided with a pole post hole 1111, and the pole post 140 is installed through the pole post hole 1111 and is insulated and fixedly installed on the end wall 111. The end of the pole post 140 facing the electrode assembly 120 passes through the end wall 111 and is directly electrically connected to the positive electrode tab 125 or indirectly connected via a transfer connection. The structure of the pole post 140 can be any suitable form that can pass through the end wall 111 and be electrically connected to the positive electrode tab 125 of the electrode assembly 120. For example, the cross-section can be circular, square, prismatic, or an irregular contour that can achieve stable conductivity. The shape of the pole post hole 1111 corresponds to the shape of the pole post 140. In this embodiment, the cross-section of the pole post 140 is circular.

[0058] There are various ways to fix the pole post 140 to the end wall 111. In one embodiment, please refer to [reference needed]. Figure 3 The electrode post 140 includes a columnar portion 142, a first limiting portion 141, and a second limiting portion 143. The first limiting portion 141 and the second limiting portion 143 are respectively disposed at both ends of the columnar portion 142 in the height direction, and both extend from the outer periphery of the columnar portion 142 to the outer periphery of the end wall 111 in the radial direction. The columnar portion 142 is installed through the electrode post hole 1111. The end of the columnar portion 142 facing the electrode assembly 120 is connected to the first limiting portion 141, that is, the first limiting portion 141 is located inside the housing 110. The end of the columnar portion 142 away from the electrode assembly 120 is connected to the second limiting portion 143, that is, the second limiting portion 143 is located outside the housing 110. The electrode post 140 is fixedly clamped to the end wall 111 by the first limiting portion 141 and the second limiting portion 143 to achieve a fixed connection between the electrode post 140 and the end wall 111.

[0059] The cross-sections of the first limiting part 141 and the second limiting part 143 can be circular, square, prismatic, or other irregular shapes that can achieve stable conductivity, etc., and this embodiment does not limit them. Optionally, in order to facilitate the production and processing of the pole post 140, in this embodiment, the outer contours of the first limiting part 141 and the second limiting part 143 are both circular contours that are coaxially arranged with the columnar part 142.

[0060] Of course, in other embodiments, the pole post 140 may not include the second limiting part 143 described in the above embodiment, but only include the interconnected columnar part 142 and the first limiting part 141. In this case, the pole post 140 and the end wall 111 can be fixed by an insulated threaded connection between the columnar part 142 and the pole post hole 1111. For example, an insulating sleeve with a threaded hole is pre-fixed in the pole post hole 1111; at the same time, an external thread is machined on the outer surface of the columnar part 141. During assembly, the columnar part 142 is screwed into the threaded hole of the insulating sleeve, and the pole post 140 and the insulating sleeve are fixedly connected by thread fastening, thereby completing the fixed installation of the pole post 140 and the end wall 111.

[0061] Please see Figure 3 To achieve a seal between the pole post 140 and the end wall 111, a sealing member 160 surrounding the columnar portion 142 is sandwiched between the second limiting portion 143 and the end wall 111. Specifically, the sealing member 160 surrounds the columnar portion 142 and is pressed between the second limiting portion 143 and the end wall 111. The sealing member 160 is made of an elastic material, such as EPDM rubber, fluorosilicone rubber, or fluororubber, but is not limited to these materials.

[0062] It should be noted that the pole post 140 and the end wall 111 are fixed by the first limiting part 141 and the second limiting part 143. In this embodiment, the pole post 140 is fixedly connected to the end wall 111 by riveting. Specifically, only the first limiting part 141 may be a riveted flange structure, only the second limiting part 143 may be a riveted flange structure, or both the first limiting part 141 and the second limiting part 143 may be riveted flange structures. Optionally, please refer to... Figure 3 In this embodiment, the first limiting part 141 is a riveted flange structure.

[0063] Please see Figure 3 The first insulating member 150 is disposed around the outer periphery of the columnar portion 142 and is at least partially sandwiched between the first limiting portion 141 and the end wall 111 to achieve insulation between the side of the end wall 111 facing the inside of the housing 110 and the first limiting portion 141. The shape and size of the first insulating member 150 are not limited. The cross-section of the first insulating member 150 can be circular, square, polygonal or other irregular shapes, as long as it meets the insulation requirements between the first limiting portion 141 and the end wall 111.

[0064] The first sealing layer 171 is disposed around the outer periphery of the columnar portion 142 and is located on the surface of the first insulating member 150 facing the end wall 111. The first sealing layer 171 may be disposed around the outer periphery of the columnar portion 142 in a circular, square, or other irregular shape, and this embodiment is not limited in this regard. The material and molding process of the first sealing layer 171 are not limited. For example, it may be achieved by coating the surface of the first insulating member 150 with lithium-ion sealant, spraying asphalt adhesive onto the surface of the first insulating member 150, or coating the surface of the first insulating member 150 with asphalt adhesive, and this embodiment is not limited in this regard.

[0065] Optionally, in one embodiment, the first sealing layer 171 is an asphalt adhesive layer formed by a coating process. Since the asphalt adhesive has certain adhesive properties at room temperature, it can adhere to the surface of the first insulating member 150 without external pressure. At the same time, when subjected to the pressure between the first limiting part 141 and the end wall 111, it can also undergo plastic flow and deformation, thereby better filling the assembly gap between the first insulating member 150 and the end wall 111, thus achieving a better sealing effect.

[0066] In another embodiment, the first sealing layer 171 is an asphalt adhesive layer formed by a spraying process. It should be noted that after the housing 110 undergoes stamping and stretching, the end wall 111 of the housing 110 will have some tiny pits in its microstructure. In this embodiment, since the asphalt spraying process can form granular particles, these particles can fill the pits 1112, thus reducing the probability of a small gap between the end wall 111 and the first insulating member 150, thereby further improving the sealing performance between the first insulating member 150 and the end wall 111.

[0067] The projections of the first insulating member 150, the first sealing layer 171, the first limiting portion 141, and the end wall 111 in the thickness direction of the end wall 111 at least partially overlap, that is, the first sealing layer 171 is at least partially located in the clamping area between the first insulating member 150, the first limiting portion 141, and the end wall 111.

[0068] In this embodiment, a first sealing layer 171 is provided on the surface of the first insulating member 150 facing the end wall 111, and the projections of the first insulating member 150, the first sealing layer 171, the first limiting part 141, and the end wall 111 in the thickness direction of the end wall 111 at least partially overlap. This structural design allows the first insulating member 150, located in the clamping area between the first limiting part 141 and the end wall 111, to not only maintain its original insulation function but also cooperate with the first sealing layer 171 to add a sealing structure between the end wall 111 and the first insulating member 150. In this way, based on the original sealing structure between the electrode post 140 and the housing 110, a sealing structure formed by the cooperation of the first insulating member 150 and the first sealing layer 171 can be superimposed, thereby forming a double-layer sealing structure between the electrode post 140 and the end wall 111. This helps to improve the sealing performance between the electrode post 140 and the housing 110 and improves the technical problem of poor sealing performance between the electrode post 140 and the housing 110 in the existing secondary battery 100. Furthermore, since the first sealing layer 171 is located within the clamping area between the first limiting portion 141 and the second limiting portion 143, during the riveting process of the electrode post 140, when the first limiting portion 141 and the second limiting portion 143 are clamped together by force, the first sealing layer 171 and the end wall 111 will be pressed together simultaneously, thereby achieving a sealing effect. This design eliminates the need for a separate clamping structure for the first sealing layer 171, thus simplifying the assembly process and improving the assembly efficiency of the secondary battery 100.

[0069] Please see Figures 4 to 6 In one embodiment of this utility model, a first groove 1531 is provided on the surface of the first insulating member 150 facing the end wall 111, and a first sealing layer 171 is disposed within the first groove 1531. The first groove 1531 surrounds the outer periphery of the columnar portion 142. The first groove 1531 can be a circular annular groove, a rectangular annular groove, or a polygonal annular groove, etc. The first sealing layer 171 being disposed in the first groove 1531 means that the material of the first sealing layer 171 fills the first groove 1531. It is understood that in order for the first sealing layer 171 to achieve a sealing effect, the filling height of the first sealing layer 171 in the first groove 1531 shall not be less than the depth of the first groove 1531, so as to ensure that the first sealing layer 171 can contact the surface of the end wall 111 at the corresponding position. Optionally, in order to facilitate the molding and manufacturing of the first groove 1531, in this embodiment, the first groove 1531 is a circular annular groove structure, and the first groove 1531 and the columnar portion 142 are substantially coaxially arranged.

[0070] In this embodiment, since a first groove 1531 is provided on the side of the first insulating member 150 facing the end wall 111, the first sealing layer 170 is compressed and filled in the first groove 1531. That is, before the pole post 140 is riveted, the first sealing layer 170 protrudes from the first groove 1531. Under the clamping action after the pole post 140 is riveted, the first sealing layer 170 is compressed and filled in the first groove 1531, ensuring the contact between the first sealing layer 170 and the end wall 111.

[0071] Of course, in other embodiments of this utility model, the surface of the first insulating member 150 facing the end wall 111 may also be without a groove structure, that is, the surface of the first insulating member 150 facing the end wall 111 is entirely flat, and the first sealing layer 171 can be directly formed on the flat surface by coating or spraying process.

[0072] Please see Figures 4 to 6 In one embodiment of this utility model, the surface of the first insulating member 150 facing the end wall 111 includes a flat area 15311 and a recessed area 15312. The flat area 15311 contacts the surface of the end wall 111 facing the electrode assembly 120, and the recessed area 15312 is recessed relative to the flat area 15311 facing the electrode assembly 120, to form the first groove 1531 in the above embodiment. This configuration simplifies the forming process of the first groove 1531 and ensures a large contact area between the first insulating member 150 and the end wall 111. A larger contact area helps to improve the stability of the clamping and positioning between the first limiting part 141 and the end wall 111, reduces the risk of displacement of the electrode post 140 during long-term use, and thus further improves the sealing reliability of the electrode post 140.

[0073] Please see Figures 8 to 10 In one embodiment of this utility model, the surface of the first insulating member 150 facing the end wall 111 includes a first annular boss 15313 and a second annular boss 15314. The first annular boss 15313 is disposed around the outer periphery of the second annular boss 15314, and the first annular boss 15313 and the second annular boss 15314 surround each other to form a first groove 1531. The first annular boss 15313 and the second annular boss 15314 can be coaxially arranged or non-coaxially arranged. Optionally, in order to facilitate the positioning and machining of the first annular boss 15313 and the second annular boss 15314, in this embodiment, the first annular boss 15313 and the second annular boss 15314 are coaxially arranged.

[0074] In this embodiment, the first groove 1531 is formed by a first annular protrusion 15313 and a second annular protrusion 15314. Its depth can be achieved by controlling the height of the first annular protrusion 15313 and the second annular protrusion 15314, rather than by reducing the thickness of the first insulating member 150. Therefore, this design ensures that the first groove 1531 has sufficient depth while maintaining the thickness of the first insulating member 150, thus avoiding any weakening of the structural support strength or insulation performance of the first insulating member 150 due to the presence of the first groove 1531.

[0075] It should be noted that, in one embodiment, the heights of the first annular protrusion 15313 and the second annular protrusion 15314 can be equal. When the first limiting portion 141 and the end wall 111 are clamped together, the top walls of both the first annular protrusion 15313 and the second annular protrusion 15314 abut against the surface of the end wall 111 facing the electrode assembly 120. In another embodiment, please refer to... Figure 8 Alternatively, the height of the second annular protrusion 15314 may be greater than the height of the first annular protrusion 15313, and the second annular protrusion 15314 may extend into the electrode post hole 1111 and abut against the hole wall of the electrode post hole 1111 and the outer peripheral surface of the columnar portion 142. When the first limiting portion 141 and the end wall 111 are clamped together, the top wall of the first annular protrusion 15313 abuts against the surface of the end wall 111 facing the electrode assembly 120.

[0076] To further improve the sealing performance between the first insulating element 150 and the end wall 111, please refer to Figure 11 and Figure 12 In one embodiment of this utility model, a second sealing layer 172 is provided on the side of the first insulating member 150 opposite to the end wall 111. The second sealing layer 172 is disposed around the outer periphery of the columnar portion 142, and the projections of the second sealing layer 172, the first sealing layer 171, and the first limiting portion 141 in the thickness direction of the end wall 111 at least partially overlap each other, that is, the second sealing layer 172 extends at least partially between the first limiting portion 141 and the first insulating member 150. The structural shape of the second sealing layer 172 may be the same as or different from that of the first sealing layer 171. The material and molding process of the second sealing layer 172 may be the same as or different from those of the first sealing layer 171. Optionally, in this embodiment, both the second sealing layer 172 and the first sealing layer 171 are distributed in a ring shape on the surface of the first insulating member 150, and both are arranged approximately coaxially with the columnar portion 142. The second sealing layer 172 uses the same material and molding process as the first sealing layer 171 to simplify the molding process of the sealing layer and reduce production costs.

[0077] By providing a second sealing layer 172 and ensuring that the projections of the second sealing layer 172, the first sealing layer 171, and the first limiting portion 141 in the thickness direction of the end wall 111 at least partially overlap, a sealing structure can be added at the contact position between the first insulating member 150 and the first limiting portion 141. This improves the sealing performance between the first limiting portion 141 and the first insulating member 150, thereby reducing the probability of electrolyte entering the electrode hole 1111 from the contact position between the first limiting portion 141 and the first insulating member 150. This further reduces the risk of electrolyte leakage and improves the sealing performance between the electrode 140 and the housing 110. Meanwhile, due to the provision of the second sealing layer 172, the first insulating member 150 located in the clamping area between the first limiting part 141 and the end wall 111 can have a region where both the upper and lower surfaces are covered with a sealing layer. This can effectively reduce the risk of volatile gases in the electrolyte escaping from the electrode hole 1111 through the first insulating member 150 and improve the sealing performance between the electrode 140 and the housing 110.

[0078] To improve the bonding strength between the sealing layer and the surface of the first insulating element 150, optionally, in one embodiment of the present invention, the surface of the first insulating element 150 may be roughened, such as by corona treatment, sandblasting, acid etching, or using a mold for texturing. Specifically, in one embodiment, surface roughening may be performed only in specific areas of the first insulating element 150 where the first sealing layer 171 and / or the second sealing layer 172 need to be provided. In another embodiment, the entire outer surface of the first insulating element 150 may be uniformly roughened. By roughening the surface of the first insulating element 150, the contact area and mechanical interlocking effect between the first insulating element 150 and the sealing layer can be effectively increased, thereby significantly improving the interfacial bonding force and ensuring the long-term reliability of the sealing structure.

[0079] In one embodiment of this utility model, when the material of the first insulating element 150 is polypropylene (PP), its surface roughness Rz is 40–120 μm. For example, the surface roughness Rz of the first insulating element 150 can be 40 μm, 80 μm, or 120 μm. When the material of the first insulating element 150 is perfluoroalkoxy resin (PFA), its surface roughness Rz is 10–60 μm. For example, the surface roughness Rz of the first insulating element 150 can be 10 μm, 35 μm, or 60 μm.

[0080] In this embodiment, the surface roughness of the first insulating component 150 is increased by corona treatment, sandblasting, acid etching, or by using textured surfaces of the mold. This allows for better contact and fit between the first insulating component 150 and the first sealing layer 171 and / or the second sealing layer 172, thereby enhancing the sealing performance.

[0081] Please see Figures 11 to 13 In one embodiment of this utility model, a second groove 1532 is provided on the surface of the first insulating member 150 facing away from the end wall 111, and a second sealing layer 172 is disposed within the second groove 1532. The outer edge of the first limiting part 141 is pressed against the second sealing layer 172 within the second groove 1532, and the thickness of the second sealing layer 172 is less than the depth of the second groove 1532. The shape and structure of the second groove 1532 can be the same as or different from the shape and structure of the first groove 1531. Optionally, in this embodiment, the second groove 1532 is an annular groove structure with the same shape as the first groove 1531, and the second groove 1532 and the first groove 1531 are coaxially arranged. This arrangement facilitates the positioning and processing of the second groove 1532 relative to the first groove 1531, which is beneficial to improving processing efficiency.

[0082] In this embodiment, a second groove 1532 is provided on the side of the first insulating member 150 facing away from the end wall 111, and a second sealing layer 172 is disposed within the second groove 1532, with the thickness of the second sealing layer 172 being less than the depth of the second groove 1532. This design effectively constrains the movement range of the second sealing layer 172 when the first limiting part 141 presses against it, causing displacement. This significantly reduces the risk of the second sealing layer 172 overflowing from between the first limiting part 141 and the first insulating member 150 due to pressure, thereby improving the stability of the sealing effect between the first limiting part 141 and the first insulating member 150.

[0083] Please see Figure 14 Furthermore, in one embodiment of this utility model, along the radial direction of the columnar portion 142, the distance between the outer edge of the second groove 1532 and the outer edge of the first limiting portion 141 is W1, where 0.5mm ≤ W1 ≤ 10mm. For example, W1 can be 0.5mm, 5mm, or 10mm, etc. The width of the second groove 1532 is W2, and 0.5mm ≤ W2 ≤ 5mm. For example, W2 can be 0.5mm, 2.5mm, or 5mm, etc., and W1 < W2.

[0084] In this embodiment, by ensuring that 0.5mm≤W1≤10mm, it is possible not only to ensure that the second sealing layer 172 can fully cover the critical sealing area between the first limiting part 141 and the first insulating member 150, so as to form a sufficient sealing contact area between the two; but also to avoid material waste caused by the excessive area of ​​the second sealing layer 172 while ensuring sealing performance, which is beneficial to controlling the production cost of the sealing layer.

[0085] Furthermore, in one embodiment of this utility model, please refer to... Figure 16 The second groove 1532 is formed by a third annular boss 15315 and a fourth annular boss 15316, with the fourth annular boss 15316 coaxially surrounding the outer periphery of the third annular boss 15315. Along the radial direction of the second groove 1532, the distance between the inner edge of the second groove 1532 and the edge of the third annular boss 15315 away from the fourth annular boss 15316 is W2, and 0.5mm ≤ W2 ≤ 5mm. For example, W2 can be 0.5mm, 2.5mm, or 5mm, etc.

[0086] If the dimension W2 is too large, under the condition that the width of the second groove 1532 is constant, the pressing area between the first limiting part 141 and the second sealing layer 172 in the second groove 1532 will be reduced accordingly. The reduction in pressing area will lead to uneven distribution of contact pressure, which is not conducive to forming a good sealing performance. On the other hand, if the dimension W2 is too small, it will be not conducive to the molding of the first insulating part 150, increasing the molding difficulty. Therefore, in this embodiment, by limiting the dimension W2 to between 0.5 and 5 mm, the molding requirements of the first insulating part 150 can be met, as well as the pressing area requirements between the first limiting part 141 and the second sealing layer 172, ensuring the sealing performance between the first limiting part 141 and the first insulating part 150.

[0087] Please see Figure 21 and Figure 22 In one embodiment of this utility model, no second sealing layer 172 is provided between the first limiting part 141 and the first insulating member 150, and the first limiting part 141 is a riveted flange. Under the riveting action, the first limiting part 141 bends and deforms, pressing inward onto the first insulating member 150. Due to the large riveting force, the surface of the first insulating member 150 is deformed by the first limiting part 141, thereby forming a first recess 191. The area where the first limiting part 141 and the first insulating member 150 abut is at least partially filled in the first recess 191. This structural design can ensure a stable pressing fit between the first limiting part 141 and the first insulating member 150, thereby keeping the first insulating member 150 and the end wall 111 in a clamped and fixed state. Furthermore, the first sealing layer 171 and the end wall 111 can be effectively pressed together, thereby achieving the expected sealing performance.

[0088] Please participate Figure 23 and Figure 24 In one embodiment of this utility model, a second sealing layer 172 is provided between the first limiting part 141 and the first insulating member 150. The second sealing layer 172 is an asphalt adhesive layer. The first limiting part 141 is a riveted flange, and its outer edge is pressed against the second sealing layer 172. Under riveting pressure, the first limiting part 141 bends and deforms, pressing inward against the second sealing layer 172. The surface of the second sealing layer 172 is deformed by the pressure of the first limiting part 141, thereby forming a second recess 192. At the same time, a large riveting pressure is transmitted to the first insulating member 150 through the second sealing layer 172, causing the first insulating member 150 to be deformed by compression, thereby forming the first recess 191. The area where the first limiting part 141 and the second sealing layer 172 abut against each other is at least partially filled in the second recess 192, and the area where the second sealing layer 172 and the first insulating member 150 abut against each other is at least partially filled in the first recess 191.

[0089] It should be noted that in other embodiments, when a second sealing layer 172 is provided between the first limiting part 141 and the first insulating member 150, and the second sealing layer 172 is a lithium-ion adhesive layer, under the riveting action, the first limiting part 141 will undergo riveting deformation and be pressed inward onto the second sealing layer 172. At this time, the lithium-ion adhesive layer itself will generate a large elastic deformation, forming a second recess 192. Since the deformation of the lithium-ion adhesive layer can absorb the riveting pressure generated by the first limiting part 141, the riveting force can be prevented from being transmitted to the first insulating member 150, and thus the first recess 191 will not be generated on the first insulating member 150.

[0090] Based on the previous embodiment, further, in one embodiment of this utility model, please refer to... Figure 12 The outer edge of the first groove 1531 extends to the outer side of the outer edge of the first limiting portion 141, and the distance between the groove and the outer edge of the first limiting portion 141 is W3, where 0.5mm ≤ W3 ≤ 10mm. For example, W3 can be 0.5mm, 5mm, or 10mm. In this embodiment, by ensuring that 0.5mm ≤ W3 ≤ 10mm, it is possible not only to ensure that the first sealing area forms a sufficient sealing contact surface within the clamping area between the first limiting portion 141 and the end wall 111, thus ensuring a certain sealing effect, but also to avoid material waste caused by an excessively large area of ​​the first sealing layer 171 while ensuring sealing performance, which is beneficial for controlling production costs.

[0091] Please see Figure 13In one embodiment of this utility model, the depth of the first groove 1531 is T1, where 0.03mm ≤ T1 ≤ 0.3mm. For example, the depth T1 can be 0.03mm, 0.15mm, or 0.3mm, etc. The depth of the second groove 1532 is T2, where 0.03mm ≤ T2 ≤ 0.3mm. For example, the depth T2 can be 0.03mm, 0.15mm, or 0.3mm, etc. It should be noted that the depth T1 of the first groove 1531 and the depth T2 of the second groove 1532 can be equal or unequal. Optionally, in this embodiment, to facilitate the processing of the grooves and simplify the forming process of the sealing layer, the depth T1 of the first groove 1531 and the depth T2 of the second groove 1532 are equal. By setting the depth T1 of the first groove 1531 and the depth T2 of the second groove 1532 to be between 0.03mm and 0.3mm, this setting can ensure that the minimum thickness of the first sealing layer 171 and the second sealing layer 172 can meet the sealing performance requirements, and can also avoid the waste of sealing material and the increase in production cost caused by the excessive thickness of the first sealing layer 171 and the second sealing layer 172.

[0092] Please see Figures 17 to 19 In one embodiment of this utility model, the second limiting portion 143 is a riveted flange structure. A second insulating member 180 is sandwiched between the second limiting portion 143 and the end wall 111. A third sealing layer 173 is provided on the side of the second insulating member 180 facing the end wall 111 and / or the side facing the second limiting portion 143. The projections of the second insulating member 180, the third sealing layer 173, the second limiting portion 143, and the end wall 111 in the thickness direction of the end wall 111 at least partially overlap each other. Specifically, please refer to... Figure 20 In one embodiment, the second insulating member 180 has a third sealing layer 173 only on the side facing the end wall 111. See also... Figure 18 In another embodiment, the second insulating member 180 has a third sealing layer 173 only on the side facing the second limiting portion 143. See also... Figure 19 In other embodiments, the third sealing layer 173 may be provided in two sets, one set being provided on the side of the second insulating member 180 facing the end wall 111, and the other set being provided on the side of the second insulating member 180 facing the second limiting portion 143.

[0093] In this embodiment, a third sealing layer 173 is provided on the side of the second insulating member 180 facing the end wall 111 and / or the side facing the second limiting portion 143, and the projections of the second insulating member 180, the third sealing layer 173, the second limiting portion 143, and the end wall 111 in the thickness direction of the end wall 111 at least partially overlap. This allows the second insulating member 180, located within the clamping area between the second limiting portion 143 and the end wall 111, to not only maintain its original insulation function but also cooperate with the third sealing layer 173 to form an additional sealing structure between the second limiting portion 143 and the end wall 111. This reduces the probability of electrolyte leakage from the installation gap between the second limiting portion 143 and the end wall 111, thereby further reducing the risk of electrolyte leakage and further improving the sealing performance between the electrode post 140 and the housing 110.

[0094] It should be noted that the structural shape of the third sealing layer 173 can be the same as or different from that of the first sealing layer 171. The material and molding process of the third sealing layer 173 can be the same as or different from those of the first sealing layer 171; this embodiment is not limited in this regard. In one embodiment, the surface of the second insulating member 180 can be a planar structure, and the third sealing layer 173 can be directly disposed on the planar surface. In another embodiment, the surface of the second insulating member 180 can be provided with the structure of the first groove 1531 or the second groove 1532 described above, so that the third sealing layer 173 is disposed within the groove.

[0095] Please see Figure 25 In one embodiment of the battery pack 200 of this utility model, the battery pack 200 includes a housing 210 and at least one secondary battery 100. The housing 210 includes a first housing portion 211 and a second housing portion 212, which cover each other to form a receiving space. Multiple secondary batteries 100 are housed within the receiving space, and the multiple secondary batteries 100 can be connected in series and / or in parallel. The battery pack 200 can be a battery module, a battery pack, etc.

[0096] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A secondary battery, characterized in that, include: The housing includes an end wall and a side wall surrounding the end wall, the end wall being provided with a pole post hole; The electrode assembly is disposed inside the housing; An electrode post is fixed to the end wall and electrically connected to the electrode assembly; the electrode post includes a columnar portion and a first limiting portion and a second limiting portion respectively connected to both ends of the columnar portion. The columnar portion passes through the electrode post hole. The first limiting portion is located inside the housing and extends from the columnar portion to the outer periphery of the end wall. The second limiting portion is located outside the housing and extends from the columnar portion to the outer periphery of the end wall. A first insulating member is disposed around the outer periphery of the columnar portion and is at least partially clamped between the first limiting portion and the end wall; A first sealing layer is disposed around the outer periphery of the columnar portion and is located on the surface of the first insulating member facing the end wall. Wherein, the projections of the first insulating element, the first sealing layer, the first limiting portion, and the end wall in the thickness direction of the end wall at least partially overlap each other.

2. The secondary battery according to claim 1, characterized in that, The first insulating member has a first groove on the surface facing the end wall, and the first sealing layer is disposed in the first groove.

3. The secondary battery according to claim 2, characterized in that, The surface of the first insulating member facing the end wall includes a flat area and a recessed area. The flat area abuts against the end wall, and the recessed area is recessed relative to the flat area towards the electrode assembly to form the first groove.

4. The secondary battery according to claim 2, characterized in that, The surface of the first insulating member facing the end wall includes a first annular boss and a second annular boss. The first annular boss is disposed around the outer periphery of the second annular boss, and the first annular boss and the second annular boss surround to form the first groove.

5. The secondary battery according to claim 2, characterized in that, A second sealing layer is provided on the side of the first insulating member away from the end wall. The second sealing layer is disposed around the outer periphery of the columnar portion, and the projections of the second sealing layer, the first sealing layer and the first limiting portion in the thickness direction of the end wall at least partially overlap each other. The second sealing layer is an asphalt adhesive layer formed by a coating process or an asphalt adhesive layer formed by a spraying process.

6. The secondary battery according to claim 5, characterized in that, The surface of the first insulating member facing away from the end wall is provided with a second groove, the second sealing layer is disposed in the second groove, the outer edge of the first limiting part is pressed against the second sealing layer, and the thickness of the second sealing layer is less than the depth of the second groove; Wherein, along the radial direction of the columnar portion, the distance between the outer edge of the second groove and the outer edge of the first limiting portion is W1, 0.5mm≤W1≤10mm; the depth of the first groove is T1, 0.03mm≤T1≤0.3mm; the depth of the second groove is T2, 0.03mm≤T2≤0.3mm.

7. The secondary battery according to claim 1, characterized in that, When the material of the first insulating component is polypropylene, its surface roughness Rz is 40-120 μm; when the material of the first insulating component is perfluoroalkoxy resin, its surface roughness Rz is 10-60 μm.

8. The secondary battery according to claim 1, characterized in that, The first limiting part is a riveted flange. The first insulating part deforms under riveting pressure and forms a first recess. The first limiting part is at least partially filled in the first recess.

9. The secondary battery according to any one of claims 1 to 8, characterized in that, The first sealing layer is an asphalt adhesive layer formed by a coating process, or the first sealing layer is an asphalt adhesive layer formed by a spraying process; and / or, The secondary battery also includes a sealing element, which is disposed around the columnar portion and located between the second limiting portion and the end wall.

10. A battery pack, characterized in that, The secondary battery includes any one of claims 1 to 9.

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