Single cell battery

Abstract

This utility model relates to the field of battery structure technology, and in particular to a single battery cell. A groove is provided on the contact surface. The first side of the groove forms a first angle with a first direction, and the first angle is less than 90°. That is, the first side is inclined along the direction away from the central axis of the electrode post. The groove structure forms a Tesla one-way valve-like effect, which can improve the flow direction of the molten material when the insulating part of the insulating component is affected by heat and is in a high-temperature molten state. It prevents the insulating component from flowing away from the central axis of the electrode post along the first direction, preserves as much volume as possible between the insulating part and the limiting part and the end wall, increases the contact area between the insulating part and the limiting part and the end wall, prevents short circuits between the electrode post and the shell, and improves insulation stability.

Description

Technical Field

[0001] This utility model relates to the field of battery structure technology, and in particular to a single-cell battery. Background Technology

[0002] Currently, the terminals of secondary batteries are insulated from the battery casing by inner and outer PFA (soluble polytetrafluoroethylene) gaskets and outer fluororubber. When the battery is short-circuited, the temperature at the terminals rises, which can easily cause the terminals and the steel casing to short-circuit, forming a secondary short circuit and causing a fire or explosion. Utility Model Content

[0003] This invention provides a single-cell battery to solve the technical problem of a short circuit between the terminal and the steel casing caused by temperature rise at the terminal, resulting in a secondary short circuit.

[0004] This utility model provides a single-cell battery, the single-cell battery comprising: The housing includes an end wall having mounting holes and a side wall surrounding the end wall, the end wall and the side wall defining an accommodating space; An electrode post includes a columnar portion and a limiting portion. The columnar portion passes through the mounting hole, and the limiting portion is connected to one end of the columnar portion away from the receiving space and extends to the outer periphery of the end wall. The limiting portion and the end wall have a first gap H1 along the axial direction of the electrode post. An insulating member is disposed around the columnar portion, at least a portion of the insulating member is disposed within the first gap, and the portion of the insulating member disposed within the first gap forms an insulating portion; The surfaces of the limiting portion and the insulating portion, and the end wall and the insulating portion, are called contact surfaces. The contact surfaces include a first contact surface of the limiting portion for contacting the insulating portion, and a second contact surface of the end wall for contacting the insulating portion. The first contact surface and / or the second contact surface are provided with grooves. The inner side of the groove includes a first side surface and a second side surface that are opposite to each other along a first direction. The first direction is defined as the direction perpendicular to the axial direction of the pole post. The first side surface is closer to the central axis of the pole post than the second side surface. The angle between the first side and the first direction is a first angle α, and the first side extends along the first direction in a direction away from the central axis, and the first angle α is less than 90°.

[0005] In one embodiment of the present invention, the insulating part has a mating surface that contacts the limiting part and the end wall, and the mating surface is provided with a protrusion that mates with the inner side surface of the groove.

[0006] In one embodiment of the present invention, the groove includes a first groove disposed on the first contact surface and a second groove disposed on the second contact surface; the mating surface includes a first mating surface that contacts the limiting portion and a second mating surface that contacts the end wall; the protrusion includes a first protrusion disposed on the first mating surface and a second protrusion disposed on the second mating surface; the outer contour of the first protrusion is adapted to the inner surface of the first groove, and the outer contour of the second protrusion is adapted to the inner surface of the second groove.

[0007] In one embodiment of the present invention, there are multiple first grooves and multiple second grooves. The first grooves are arranged at intervals along the first direction, and the second grooves are arranged at intervals along the first direction. Each first groove and its corresponding second groove along the axial direction are staggered in the first direction.

[0008] In one embodiment of the present invention, the protrusion is injection molded into the groove.

[0009] In one embodiment of the present invention, the angle between the second side and the first direction is a second included angle β, and the second included angle β is greater than the first included angle α; the second included angle β is greater than or equal to 90°.

[0010] In one embodiment of the present invention, the grooves are continuously distributed along a circular trajectory with the central axis as the center; or, the grooves are spaced apart along a circular trajectory with the central axis as the center.

[0011] In one embodiment of this utility model, the insulating component is made of TPI material.

[0012] In one embodiment of the present invention, the single cell further includes a sealing member disposed around the columnar portion, the sealing member including at least a first portion clamped within the first gap, and the first portion being closer to the central axis than the insulating portion, and a second gap along the first direction being formed between the first portion and the insulating portion.

[0013] In one embodiment of this utility model, the groove is formed by engraving or cold forging, and the electrode post is made of aluminum or copper.

[0014] The beneficial effects of this utility model are as follows: The single battery proposed in this utility model has a groove on the contact surface. The angle between the first side of the groove and the first direction is a first angle, and the first angle is less than 90°. That is, the first side is inclined along the direction away from the central axis of the electrode post. The groove structure forms a Tesla one-way valve-like effect, which can improve the flow direction of the molten material when the insulating part of the insulating component is affected by heat and is in a high-temperature molten state. It prevents the insulating component from flowing away from the central axis of the electrode post along the first direction, preserves as much volume of the insulating part as possible between the limiting part and the end wall, increases the contact area between the insulating part and the limiting part and the end wall, prevents short circuit between the electrode post and the shell, and improves insulation stability. Attached Figure Description

[0015] 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.

[0016] In the attached diagram: Figure 1 An exploded view of the overall structure of a single battery cell provided in an embodiment of this utility model; Figure 2 This is a schematic diagram of the pole post structure provided in one embodiment of the present utility model; Figure 3 for Figure 2 Sectional view at point AA; Figure 4 for Figure 3 A magnified view of a portion of the image; Figure 5 This is a schematic diagram showing the fit between the pole post, end wall, and insulating component in one embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of an insulating component provided in one embodiment of the present invention; Figure 7 for Figure 6 Sectional view at point BB; Figure 8 This is a partial structural diagram of the end wall provided in one embodiment of the present invention.

[0017] The attached figures are labeled as follows: 1-Housing; 11-End wall; 11a-Second contact surface; 12-End wall; 2-Position post; 21-Columnar portion; 22-Limiting portion; 22a-First contact surface; 23-Groove; 231-First groove; 232-Second groove; 23a-First side surface; 23b-Second side surface; 3-Insulating member; 31-Insulating portion; 311-First mating surface; 31a-Protrusion; 312-Second mating surface; 4-Sealing member; α-First included angle; β-Second included angle; H1-First gap; H2-Second gap. Detailed Implementation

[0018] 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.

[0019] 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.

[0020] 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.

[0021] Please see Figure 1 , Figure 1 A single battery provided in one embodiment of this utility model, such as Figures 1 to 8 As shown, a single cell includes: The housing 1 includes an end wall 11 with mounting holes and a side wall 12 surrounding the end wall 11, the end wall 11 and the side wall 12 defining an accommodating space; The pole post 2 includes a columnar portion 21 and a limiting portion 22. The columnar portion 21 passes through the mounting hole, and the limiting portion 22 is connected to one end of the columnar portion 21 that is away from the receiving space and extends to the outer periphery of the end wall 11. The limiting portion 22 and the end wall 11 have a first gap H1 along the axial direction of the pole post 2. An insulating member 3 is disposed around the columnar portion 21, at least a portion of the insulating member 3 is disposed within the first gap H1, and the portion of the insulating member 3 disposed within the first gap H1 forms an insulating portion 31; Among them, the surfaces of the limiting part 22 and the insulating part 31 that contact each other and the surfaces of the end wall 11 and the insulating part 31 that contact each other are contact surfaces. The contact surfaces include the first contact surface 22a of the limiting part 22 for contacting the insulating part 31, and the contact surfaces also include the second contact surface 11a of the end wall 11 for contacting the insulating part 31. The first contact surface 22a and / or the second contact surface 11a are provided with grooves 23. The inner side surface of the groove 23 includes a first side surface 23a and a second side surface 23b that are opposite to each other along a first direction. The direction perpendicular to the axial direction of the pole post 2 is defined as the first direction. The first side surface 23a is closer to the central axis of the pole post 2 than the second side surface 23b. The angle between the first side surface 23a and the first direction is the first included angle α, and the first side surface 23a extends along the first direction in a direction away from the central axis, and the first included angle α is less than 90°.

[0022] Specifically, such as Figure 1 As shown, the single-cell battery includes a housing 1, electrode posts 2, and insulating components 3. The housing 1 includes an end wall 11 and a side wall 12 surrounding the end wall 11. The end wall 11 has mounting holes extending through its thickness. As long as a stable seal and electrical connection can be formed, the connection between the end wall 11 and the side wall 12 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the side wall 12 is not limited; it can be cylindrical or prismatic, or it can follow any other closed-loop contour that matches the end wall 11. In this embodiment, the outer edge of the end wall 11 is circular, and the side wall 12 is cylindrical and surrounds the outer edge of the end wall 11. The housing 1, formed by the end wall 11 and the side wall 12, has a receiving space for accommodating electrode components, electrolyte, and other necessary battery components.

[0023] like Figure 2 , Figure 3 , Figure 5 As shown, the pole post 2 includes a columnar portion 21 and a limiting portion 22. The columnar portion 21 is installed through the mounting hole and is insulated from the end wall 11. The cross-section of the columnar portion 21 along the radial direction of the housing 1 can be circular, square, prismatic, or an irregular shape that can achieve stable conductivity. The mounting hole corresponds to the shape of the columnar portion 21. In this embodiment, the cross-section of the columnar portion 21 along the radial direction of the housing 1 is circular. The limiting portion 22 is arranged around the top edge of the columnar portion 21. It can also be understood that the limiting portion 22 is formed by bending the top edge of the columnar portion 21 outward along the radial direction of the columnar portion 21. There is a first gap H1 between the bottom wall of the limiting portion 22 and the top wall of the end wall 11 along the axial direction of the columnar portion 21.

[0024] like Figures 5 to 7 As shown, the insulating member 3 is arranged around the outer periphery of the limiting part 22 and extends at least partially into the first gap H1. The portion of the insulating member 3 extending into the first gap H1 is the insulating part 31. The insulating part 31 can separate and insulate the limiting part 22 from the shell wall along the axial direction of the columnar part 21. It can also be understood that the insulating part 31 can separate and insulate the pole 2 from the shell 1 along the axial direction of the columnar part 21, preventing the pole 2 from short-circuiting with the shell 1 and causing a fire or explosion. When the volume of the insulating part 31 in the first gap H1 is insufficient, the pole 2 will have a certain degree of eccentricity in the high-temperature molten state of the insulating member 3. If the degree of eccentricity is too large, it will easily lead to a short circuit between the pole 2 and the shell 1, forming a secondary short circuit.

[0025] like Figure 2 and Figure 3 As shown, the surfaces of the limiting portion 22 and the end wall 11 that contact the insulating portion 31 are called contact surfaces, which include a first contact surface 22a and a second contact surface 11a. The side of the limiting portion 22 facing the insulating portion 31 is the first contact surface 22a, which can also be understood as the side of the limiting portion 22 facing the end wall 11. The side of the end wall 11 facing the insulating portion 31 is the second contact surface 11a, which can also be understood as the side of the end wall 11 facing the limiting portion 22. At least one of the first contact surface 22a and the second contact surface 11a is provided with a groove 23. The inner surface of the groove 23 includes a first side surface 23a and a second side surface 23b, which are arranged opposite to each other along a first direction. The first direction is perpendicular to the axial direction of the pole post 2, which can also be understood as the radial direction along the columnar portion 21. Specifically, the inner surface near the central axis of the pole post 2 is the first side surface 23a, and the inner surface away from the central axis of the pole post 2 is the second side surface 23b. The cross-sectional shape of the groove 23 along the axial direction of the columnar portion 21 can be any shape that can realize this embodiment.

[0026] like Figure 4 As shown, the angle between the first side surface 23a and the first direction is the first included angle α, which is less than 90°. It should be noted that the first included angle α refers to the angle further away from the central axis of the pole post 2 than the two included angles formed by the first side surface 23a and the first direction. This creates a structure similar to a "Tesla one-way valve" within the groove 23, allowing the fluid formed after the insulating component 3 melts at high temperature to flow radially inward along the columnar portion 21 within the groove 23. This increases the volume of the insulating portion 31 between the limiting portion 22 and the housing 1, increases the contact area between the insulating portion 31 and the limiting portion 22 and the housing wall, reduces the load on the insulating portion 31, and reduces the deformation degree of the insulating portion 31. This improves the problem of pole post 2 eccentricity, avoids short circuit between pole post 2 and housing 1, and achieves insulation and pressure resistance effects.

[0027] In this embodiment, a groove 23 is provided on the contact surface. The angle between the first side 23a of the groove 23 and the first direction is the first angle α, and the first angle α is less than 90°. That is, the first side 23a is inclined along the direction away from the central axis of the pole post 2. The groove 23 structure forms a Tesla-like one-way valve effect, which can improve the flow direction of the molten material when the insulating part 31 of the insulating member 3 is affected by heat and is in a high-temperature molten state. It prevents the insulating member 3 from flowing away from the central axis of the pole post 2 along the first direction, preserves the volume of the insulating part 31 between the limiting part 22 and the end wall 11 as much as possible, increases the contact area between the insulating part 31 and the limiting part 22 and the end wall 11, prevents short circuit between the pole post 2 and the housing 1, and improves the insulation stability.

[0028] In some implementations, such as Figure 7 As shown, the insulating part 31 has a mating surface that contacts the limiting part 22 and the end wall 11, and the mating surface is provided with a protrusion 31a that mates with the inner side surface of the groove 23.

[0029] Specifically, a protrusion 31a is provided on the mating surface corresponding to the groove 23 and engaging with the groove 23. The engagement between the groove 23 and the protrusion 31a firstly serves to position the contact surface and the mating surface; secondly, it also improves the sealing effect between the contact surface and the mating surface.

[0030] In some implementations, such as Figure 4 As shown, the angle between the second side 23b and the first direction is the second included angle β, and the second included angle β is greater than the first included angle α; the second included angle β is greater than or equal to 90°.

[0031] It should be noted that the second included angle β refers to the angle that is further away from the central axis of the pole post 2 among the two included angles formed between the second side surface 23b and the first direction. Increasing the inclination of the second side surface 23b toward the central axis of the pole post 2 further improves the flow direction of the molten material when the insulating part 31 of the insulating member 3 is affected by heat and is in a high-temperature molten state, preventing the insulating member 3 from flowing away from the central axis of the pole post 2 along the first direction, retaining more of the volume of the insulating part 31 between the limiting part 22 and the end wall 11, and increasing the contact area between the insulating part 31 and the limiting part 22 and the end wall 11.

[0032] In some implementations, such as Figure 3 , Figure 4 , Figure 5 and Figure 8As shown, the groove 23 includes a first groove 231 disposed on the first contact surface 22a and a second groove 232 disposed on the second contact surface 11a. The insulating part 31 has a first mating surface 311 that contacts the limiting part 22 and a second mating surface 312 that contacts the end wall. The protrusion 31a includes a first protrusion disposed on the first mating surface 311 and a second protrusion disposed on the second mating surface 312. The outer contour of the first protrusion is adapted to the inner surface of the first groove 231, and the outer contour of the second protrusion is adapted to the inner surface of the second groove 232.

[0033] First, it improves the positioning effect between the first contact surface 22a and the first mating surface 311, and between the first contact surface 22a and the second mating surface 312; second, it can further improve the sealing effect between the first contact surface 22a and the first mating surface 311, and between the first contact surface 22a and the second mating surface 312; and, it can be understood that Tesla one-way valve structures are provided on both sides of the columnar portion 21 along the axial direction within the first gap H1, further improving the flow direction of its molten material, preventing the insulating member 3 from flowing in the first direction away from the central axis of the pole post 2, and improving the one-way self-locking effect of the insulating member 3 in the molten state.

[0034] Furthermore, the cross-sectional shape of the groove 23 along the axial direction of the housing 1 can be circular, triangular, rectangular, or trapezoidal, etc., to achieve any shape required in this embodiment. When the intersection of adjacent sides of the groove 23 is a broken line, it can be connected and positioned by the cooperation between the groove 23 and the protrusion 31a, which can improve the sealing performance while ensuring coaxiality. It should be noted that the molding process can be carried out by molding each structural component independently and then assembling them in a position; or, the tooling can be used to position the pole post 2 and the housing 1, and then the insulating component 3 can be injection molded.

[0035] In some implementations, such as Figure 3 , Figure 4 , Figure 5 and Figure 8 As shown, each first groove 231 and its corresponding second groove 232 along the axial direction are staggered in a first direction. When the first groove 231 and the second groove 232 are staggered in the radial direction of the housing 1, the flow direction of the molten material is further improved, and the one-way self-locking effect of the Tesla one-way valve structure is better.

[0036] It should be noted that the second groove 232 corresponding to the first groove 231 along the axial direction refers to at least one second groove 232 located at the corresponding position along the axial direction and closest to the first groove 231. Specifically, the number of first grooves 231 and second grooves 232 is equal, and they are arranged in a one-to-one correspondence along the axial direction of the housing 1. Each first groove 231 has a second groove 232 corresponding to it along the axial direction of the housing 1.

[0037] In one example, there are three first grooves 231 and three second grooves 232. Along the radial direction of the housing 1, the outermost first groove 231 corresponds to the outermost second groove 232; the middle first groove 231 corresponds to the middle second groove 232; and the innermost first groove 231 corresponds to the innermost second groove 232. Further, the offset arrangement includes complete offset and partial offset. Complete offset means that the projections of the first groove 231 and the corresponding second groove 232 along the axial direction of the housing 1 do not overlap. Partial offset means that the projections of the first groove 231 and the corresponding second groove 232 along the axial direction of the housing 1 partially overlap. For example, the projection of either the first side surface 23a or the second side surface 23b of the first groove 231 along the axial direction of the housing 1 lies within the corresponding second groove 232.

[0038] In some implementations, such as Figure 3 , Figure 4 , Figure 5 and Figure 8 As shown, there are multiple grooves 23, arranged at intervals along the first direction. That is, there are multiple first grooves 231 and multiple second grooves 232, with multiple first grooves 231 arranged at intervals along the first direction and multiple second grooves 232 arranged at intervals along the first direction. The first gap H1 forms a straight section at the interval between two grooves 23, and the molten insulating component 3 forms a relatively regular laminar flow path when flowing in the straight section. In laminar flow, the energy dissipation inside the fluid mainly comes from the viscous shear force between fluid layers. This dissipation is much smaller than the energy loss caused by violent eddies and mixing in turbulent flow. Maintaining laminar flow can significantly reduce pressure loss (pressure drop) when transporting fluid, thereby slowing down the radial outward flow velocity of the molten insulating component 3 along the columnar body. Multiple grooves 23 can also improve the one-way self-locking effect of the Tesla one-way valve structure formed by the grooves 23, thereby further improving the flow direction of the molten insulating component 3.

[0039] In some embodiments, the protrusion 31a is injection molded into the groove 23. The insulating member 3 (insulating part 31) is directly injection molded into the first gap H1 by using an injection molding process, which solves the fit tolerance problem between the limiting part 22, the end wall 11 and the insulating part 31, and improves the sealing performance.

[0040] In some embodiments, the grooves 23 are continuously distributed along a circular trajectory with the central axis of the pole post 2 as the center; or, the grooves 23 are distributed at intervals along a circular trajectory with the central axis of the pole post 2 as the center.

[0041] It can be understood that the groove 23 is set as a continuous ring along the circumference of the columnar portion 21, which facilitates processing and improves the uniformity of the molten insulating component 3 distributed along the circumference of the columnar portion 21.

[0042] Alternatively, the grooves 23 are spaced apart along the circumference of the columnar portion 21 to improve the sealing effect between two adjacent grooves 23 along the circumference of the columnar portion 21.

[0043] In some embodiments, the insulating member 3 is made of TPI (thermoplastic polyimide). TPI material is not easily carbonized at high temperatures and has strong thermoplasticity. When the contact area between the insulating part 31 and the limiting part 22 and the shell wall is too small, the insulating part 31 in the molten state is subjected to a large force load, and the TPI material is more prone to deformation and leakage. By increasing the contact area between the insulating part 31 and the limiting part 22 and the shell wall, the force load on the TPI is reduced, the degree of deformation of the insulating part 31 is improved, thereby improving the short circuit between the pole 2 and the shell 1.

[0044] As the temperature continues to rise, TPI material exhibits strong thermoplastic properties. TPI material in the molten state has stronger fluidity, and the structure similar to a one-way valve formed by the groove 23 can further increase the volume of the insulating part 31 within the first gap H1, increase the contact area between the insulating part 31 and the limiting part 22 and the shell wall, achieve insulation and pressure resistance, and further improve the short circuit between the pole 2 and the shell 1.

[0045] In some implementations, such as Figure 1 and Figure 5 As shown, the single cell also includes a sealing member 4 disposed around the columnar portion 21. The sealing member 4 includes at least a first portion clamped within the first gap H1, and the first portion is closer to the central axis of the pole post 2 than the insulating portion 31. The first portion and the insulating portion 31 have a second gap H2 along the first direction.

[0046] In one example, the sealing member 4 is a sealing gasket, and the thickness of the sealing gasket needs to be greater than the thickness of the insulating part 31 to ensure that the sealing gasket has a certain amount of compression during the riveting process. By setting a second gap H2 along the radial direction of the pole post 2 between the first part and the insulating part 31, the molten insulating part 31 can be provided with inward flow space along the radial direction of the pole post 2; at the same time, it can also meet the requirement of the sealing gasket being compressed and extended; it can also prevent the sealing gasket from being affected by the interference of the insulating part 31 on its periphery, thus affecting the sealing performance after assembly; and it can automatically compensate for engineering errors. The second gap H2 allows the sealing gasket to slide freely and align itself during the compression process, achieving uniform compression and avoiding local over-compression or sealing failure.

[0047] In some embodiments, the groove 23 is formed by scoring or cold heading, and the pole post 2 is made of aluminum or copper. The groove 23 can be formed directly by cold heading or by secondary machining. Scoring has higher machining accuracy but increases the number of process steps, while cold heading has lower machining accuracy but better process compatibility and is less likely to generate machining stress, which is beneficial to maintaining the strength of the pole post 2.

[0048] In one example, the single-cell battery assembly process of this embodiment is as follows: The terminal post 2 is made of aluminum. The aluminum terminal post 2 is formed into a sleeve structure through processes such as cold forging. The insulating component 3 is made of TPI material and is injection molded to interlock with the terminal post 2. Then, a sealing gasket, a housing 1, and a lower plastic are sequentially placed in. The housing 1 interlocks with the insulating component 3. The terminal post 2 is riveted together through multiple riveting processes. When the aluminum terminal post 2 sleeve is placed into the inverted housing 1, it can be positioned and connected using the coaxial positioning of the lower plastic and the groove 23 structure on the housing 1. When mechanically connecting the terminal post 2 using an internal riveting process, the positioning of the terminal post 2 and the housing 1 still requires some positioning and fastening fixtures.

[0049] 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 single-cell battery, characterized in that, include: The housing includes an end wall having mounting holes and a side wall surrounding the end wall, the end wall and the side wall defining an accommodating space; An electrode post includes a columnar portion and a limiting portion. The columnar portion passes through the mounting hole, and the limiting portion is connected to one end of the columnar portion away from the receiving space and extends toward the outer periphery of the end wall. A first gap is formed between the limiting portion and the end wall along the axial direction of the electrode post. An insulating member is disposed around the columnar portion, at least a portion of the insulating member is disposed within the first gap, and the portion of the insulating member disposed within the first gap forms an insulating portion; Wherein, the surface of the limiting part that contacts the insulating part and the surface of the end wall that contacts the insulating part are both contact surfaces. The contact surface includes a first contact surface of the limiting part for contacting the insulating part, and the contact surface also includes a second contact surface of the end wall for contacting the insulating part. The first contact surface and / or the second contact surface are provided with a groove. The inner side surface of the groove includes a first side surface and a second side surface that are opposite to each other along a first direction. The first direction is defined as the direction perpendicular to the axial direction of the pole post. The first side surface is closer to the central axis of the pole post than the second side surface. The angle between the first side and the first direction is a first angle α, and the first side extends along the first direction in a direction away from the central axis, and the first angle α is less than 90°.

2. The single-cell battery according to claim 1, characterized in that, The insulating part has a mating surface that contacts the limiting part and the end wall, and the mating surface has a protrusion that mates with the inner side surface of the groove.

3. The single-cell battery according to claim 2, characterized in that, The groove includes a first groove disposed on the first contact surface and a second groove disposed on the second contact surface. The mating surface includes a first mating surface that contacts the limiting portion and a second mating surface that contacts the end wall. The protrusion includes a first protrusion disposed on the first mating surface and a second protrusion disposed on the second mating surface. The outer contour of the first protrusion is adapted to the inner surface of the first groove, and the outer contour of the second protrusion is adapted to the inner surface of the second groove.

4. The single-cell battery according to claim 3, characterized in that, There are multiple first grooves and multiple second grooves. The first grooves are arranged at intervals along the first direction, and the second grooves are arranged at intervals along the first direction. Each first groove and its corresponding second groove along the axial direction are staggered in the first direction.

5. The single-cell battery according to claim 2, characterized in that, The protrusion is injection molded into the groove.

6. The single-cell battery according to claim 1, characterized in that, The angle between the second side and the first direction is a second included angle β, and the second included angle β is greater than the first included angle α; the second included angle β is greater than or equal to 90°.

7. The single-cell battery according to claim 1, characterized in that, The grooves are continuously distributed along a circular trajectory with the central axis as the center; or, the grooves are spaced apart along a circular trajectory with the central axis as the center.

8. The single-cell battery according to claim 1, characterized in that, The insulating component is made of TPI material.

9. The single-cell battery according to claim 1, characterized in that, The single cell also includes a sealing member disposed around the columnar portion, the sealing member including at least a first portion clamped within the first gap, and the first portion being closer to the central axis than the insulating portion, and a second gap along the first direction between the first portion and the insulating portion.

10. The single-cell battery according to claim 1, characterized in that, The groove is formed by engraving or cold forging, and the electrode post is made of aluminum or copper.

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