Battery electrolyte fill hole sealing structure and battery

Abstract

A battery electrolyte fill hole sealing structure and a battery. The battery electrolyte fill hole sealing structure comprises a battery cover plate (100), a sealing pin (300), and a sealing cover (400); the sealing pin (300) is made of fluororubber, the sealing pin (300) is in interference fit with an electrolyte fill hole (110) on the battery cover plate (100), the compression ratio Ψ of the sealing pin (300) in the radial direction thereof satisfies the value range of 5.08% to 10.6%, and a first sealing surface is formed between the sealing pin (300) and the electrolyte fill hole (110); the sealing cover (400) is arranged in an accommodating recess (120) on the battery cover plate (100), the sealing cover (400) is welded to the side wall of the accommodating recess (120) and a second sealing surface is formed at the welding position.

Description

Battery liquid injection hole sealing structure and battery

[0001] The present application claims priority to the Chinese patent application No. 202410719573.3, filed on June 5, 2024, to the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, for example to a battery liquid injection hole sealing structure and a battery. BACKGROUND

[0003] Generally, a battery includes a top-opened shell and a battery cover plate, the battery cover plate is arranged at the top of the shell and connected with the shell, so that the shell forms a relatively closed space. The battery cover plate is provided with a liquid injection hole for injecting electrolyte or supplementing electrolyte into the battery. In order to prevent the subsequent leakage of the liquid injection hole, the liquid injection hole needs to be sealed.

[0004] In the related art, the sealing nail is usually inserted into the liquid injection hole to form an interference fit with the inner wall of the liquid injection hole. However, in this sealing method, if the interference amount between the sealing nail and the liquid injection hole is small, the sealing nail has the risk of being pulled out of the liquid injection hole during installation, long-term use and transportation, resulting in the failure of the sealing of the liquid injection hole, the leakage of the electrolyte inside the shell, and the safety hazard of the battery. If the interference amount between the sealing nail and the liquid injection hole is large, it is easy to cause the cracking of the battery cover plate, which also has a safety hazard. In addition, when the interference amount between the sealing nail and the liquid injection hole is large, the installation difficulty of the sealing nail is also large. SUMMARY

[0005] The present application provides a battery liquid injection hole sealing structure and a battery, which has good sealing effect, high reliability, and is easy to assemble.

[0006] The present application adopts the following technical solutions:

[0007] In one aspect, the present application provides a battery liquid injection hole sealing structure, comprising:

[0008] A battery cover plate is provided with a liquid injection hole, the liquid injection hole is used for injecting electrolyte into the shell of the battery, and the side of the battery cover plate away from the electrolyte is provided with a receiving groove, the receiving groove is coaxial with the liquid injection hole and communicates with each other;

[0009] A sealing nail made of fluororubber is arranged in the liquid injection hole and interferes with the inner wall of the liquid injection hole, and a first sealing surface is formed between the sealing nail and the inner wall of the liquid injection hole. The compression rate of the sealing nail along the radial direction of the sealing nail is Ψ, and the value of Ψ is in the range of 5.08%-10.6%;

[0010] A sealing cover is arranged in the accommodating groove, and the sealing cover comprises a shielding part, a buffer part and a welding part. The buffer part is arranged in the circumferential direction of the shielding part, and the welding part is arranged in the circumferential direction of the buffer part. The projection of the shielding part on the battery cover plate in the axial direction of the liquid injection hole completely covers the liquid injection hole and the sealing nail. The welding part is welded to the side wall of the accommodating groove and forms a second sealing surface at the welding position.

[0011] The side wall of the accommodating groove is arranged in an inclined manner. The included angle between the side wall of the accommodating groove and the bottom wall of the accommodating groove is α, and the value of α is in the range of 95°-175°. The outer circumferential surface of the welding part is arranged in an inclined manner. The included angle between the outer circumferential surface of the welding part and the bottom wall of the accommodating groove is β, and 0°≤β-α≤5°.

[0012] Optionally, the end of the liquid injection hole communicating with the accommodating groove is provided with an arc-shaped chamfer. The arc-shaped chamfer protrudes towards the direction where the sealing nail is located. The radius of the arc-shaped chamfer is r, and the value of r is in the range of 0.1mm-0.5mm.

[0013] Optionally, the height of the liquid injection hole in the axial direction of the liquid injection hole is H, and the height of the first sealing surface in the axial direction of the liquid injection hole is H1. The value of H is in the range of 0.6mm-2.0mm, and the value of H1 is in the range of 0.5mm-1.5mm.

[0014] Optionally, the height of the battery cover plate in the axial direction of the liquid injection hole is A, and the value of A is in the range of 1.5mm-3mm.

[0015] The depth of the accommodating groove in the axial direction of the liquid injection hole is B, and the value of B is in the range of 0.9mm-1.3mm.

[0016] After the sealing cover is mounted to the accommodating groove, the end face of the sealing cover away from the electrolyte is not higher than the end face of the battery cover plate away from the electrolyte. The distance between the end face of the sealing nail away from the electrolyte and the end face of the battery cover plate away from the electrolyte is b, and the value of b is in the range of 0.1mm-0.5mm.

[0017] Optionally, the penetration depth of the welding part after being welded to the side wall of the accommodating groove is h, and the penetration width is w. The value of h is in the range of 0.5mm-1.5mm, and the value of w is in the range of 0.5mm-1.0mm.

[0018] Optionally, at least part of the sealing cover protrudes away from the sealing nail and forms a avoiding space.

[0019] In another aspect, the application provides a battery, comprising a battery cover plate, a shell and an electric core, the electric core is arranged in the shell, the battery cover plate is buckled and welded with the shell, the battery cover plate is provided with a liquid injection hole, and the liquid injection hole is sealed by the battery liquid injection hole sealing structure in any of the above-mentioned aspects.

[0020] The application has the following effects:

[0021] The application provides a battery liquid injection hole sealing structure, comprising a battery cover plate, a sealing nail and a sealing cover. The battery cover plate is provided with a liquid injection hole, and the liquid injection hole can inject electrolyte into the shell. The sealing nail is made of elastic material, and the sealing nail is pressed into the liquid injection hole by a pressing nail equipment. The circumferential side of the sealing nail is in interference fit with the inner wall of the liquid injection hole. The compression rate of the sealing nail along the radial direction thereof is in the range of 5.08%-10.6%, so as to ensure that the first sealing surface between the sealing nail and the liquid injection hole has good sealing effect. At the same time, the pressing nail equipment can smoothly press the sealing nail into the liquid injection hole, without damaging the battery cover plate and being easy to assemble. The side of the battery cover plate away from the electrolyte is provided with a receiving groove, and the sealing cover is arranged in the receiving groove. The projection of the shielding part of the sealing cover on the battery cover plate completely covers the liquid injection hole and the sealing nail along the axial direction of the liquid injection hole. The welding part of the sealing cover is welded with the side wall of the receiving groove and forms a second sealing surface at the welding position. The welding part and the shielding part are connected through a buffer part. The included angle between the side wall of the receiving groove and the bottom wall of the receiving groove is α, and the value of α is in the range of 95°-175°. The outer circumferential surface of the welding part is inclined. The included angle between the outer circumferential surface of the welding part and the bottom wall of the receiving groove is β, and 0°≤β-α≤5°. The welding part is in interference fit with the side wall of the receiving groove. The liquid injection hole is sealed by the first sealing surface and the second sealing surface, so as to further improve the sealing effect of the liquid injection hole and avoid leakage of the electrolyte from the liquid injection hole.

[0022] The application also provides a battery, comprising a battery cover plate, a shell and an electric core, the electric core is arranged in the shell, the battery cover plate is buckled and welded with the shell. The battery cover plate is provided with a liquid injection hole, and the liquid injection hole is sealed by the battery liquid injection hole sealing structure. The sealing reliability of the liquid injection hole is improved by the two-layer sealing structure of the sealing nail and the sealing cover. The compression rate of the sealing nail along the radial direction thereof is controlled in the range of 5.08%-10.6%, so as to ensure that the sealing effect between the sealing nail and the liquid injection hole is good, and at the same time, the pressing nail equipment can smoothly press the sealing nail into the liquid injection hole, without damaging the battery cover plate. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 is a schematic diagram of the assembly structure of the battery cover plate and the sealing nail in the embodiment of the application;

[0024] Fig. 2 is a schematic diagram of the assembly structure of the battery cover plate, the sealing nail and the sealing cover in the embodiment of the application;

[0025] Fig. 3 is a partial enlarged view of the assembly structure of the battery cover plate and the sealing cover in the embodiment of the application;

[0026] Fig. 4 is a structural schematic view of the sealing nail in the embodiment of the application;

[0027] Fig. 5 is a structural schematic view of the sealing cover in the embodiment of the application;

[0028] Fig. 6 is a structural schematic view of the battery in the embodiment of the application;

[0029] Fig. 7 is a structural schematic view of the battery in the embodiment of the application.

[0030] In the figures: 100, battery cover plate; 110, liquid injection hole; 120, accommodating groove; 121, bottom wall; 122, side wall; 130, arc-shaped chamfer; 200, shell; 300, sealing nail; 310, sealing part; 320, liquid injection part; 400, sealing cover; 410, shielding part; 4101, avoiding space; 420, buffer part; 430, welding part; 500, battery cell. DETAILED DESCRIPTION

[0031] In the description of the application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first", "second", are only for the purpose of description, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the "upper", "above" and "on" of the first feature to the second feature include the first feature directly above and obliquely above the second feature, or only indicate that the first feature is higher in horizontal height than the second feature. The "under", "below" and "under" of the first feature to the second feature include the first feature directly below and obliquely below the second feature, or only indicate that the first feature is lower in horizontal height than the second feature.

[0032] In the description of the application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0033] Embodiments of the present application are described below in detail with reference to the accompanying drawings, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions. The embodiments described below by reference to the accompanying drawings are exemplary only, for the purpose of explanation of the present application, and are not to be understood as limiting the present application.

[0034] The present embodiment provides a battery electrolyte injection hole sealing structure, as shown in FIG. 1 and FIG. 6, which comprises a battery cover plate 100, a sealing nail 300 and a sealing cover 400. The battery cover plate 100 is used to be buckled with the shell 200 and form a containing space, and the containing space contains an electric core 500. The battery cover plate 100 is provided with an electrolyte injection hole 110, through which electrolyte can be injected into the shell 200. In order to prevent electrolyte from leaking from the electrolyte injection hole 110, a two-layer sealing structure is used in the present embodiment to seal the electrolyte injection hole 110.

[0035] Continuing to refer to FIG. 1, the first layer sealing structure is composed of the battery cover plate 100 and the sealing nail 300. The battery cover plate 100 is provided with the electrolyte injection hole 110, and the sealing nail 300 is made of elastic material and can be elastically deformed when being pressed. The sealing nail 300 is pressed into the electrolyte injection hole 110 by a pressing nail equipment, and the circumferential side of the sealing nail 300 is in interference fit with the inner wall of the electrolyte injection hole 110. At this time, the sealing nail 300 is compressed along its radial direction, so that a first sealing surface is formed between the sealing nail 300 and the inner wall of the electrolyte injection hole 110, and the gap between the sealing nail 300 and the inner wall of the electrolyte injection hole 110 is blocked by the first sealing surface, thereby preventing electrolyte from leaking. Optionally, the compression rate of the sealing nail 300 along the radial direction of the sealing nail 300 is Ψ, and the value of Ψ is in the range of 5.08%-10.6%, wherein the radial direction of the sealing nail 300 is the X-axis direction in FIG. 1. When the compression rate Ψ of the sealing nail 300 along its radial direction meets the above range, it can be ensured that the first sealing surface between the sealing nail 300 and the electrolyte injection hole 110 has good sealing effect, and the helium leak detection rate is below 1x10 -6 pa·m 3 / s. At the same time, the pressing nail equipment can successfully press the sealing nail 300 into the electrolyte injection hole 110 without damaging the battery cover plate 100.

[0036] The calculation formula of the compression rate Ψ of the sealing nail 300 along the radial direction of the sealing nail 300 is as follows: C=(D-d) / 2

[0037] Wherein, D is the diameter of the part of the sealing nail 300 located in the electrolyte injection hole 110, d is the inner diameter of the electrolyte injection hole 110, and C is the deformation amount of the part of the sealing nail 300 located in the electrolyte injection hole 110 when being compressed in the radial direction.

[0038] Exemplarily, when the diameter D of the portion of the sealing spike 300 located in the liquid injection hole 110 is 3.2 mm, the inner diameter d of the liquid injection hole 110 can be 3.0 mm. When the diameter D of the portion of the sealing spike 300 located in the liquid injection hole 110 is 3.5 mm, the inner diameter d of the liquid injection hole 110 can be 3.4 mm. In other embodiments, the diameter D of the portion of the sealing spike 300 located in the liquid injection hole 110, and the inner diameter d of the liquid injection hole 110 can also be other values, which are not listed here, as long as the compression rate Ψ is within the range of the above requirements to meet the sealing requirements. Optionally, the sealing spike 300 is integrally injection molded by fluororubber, and has a Shore hardness of 60-80 degrees, a rigidity stronger than that of polyolefin and polypropylene, an insulation resistance greater than 200 MΩ under 500 V alternating voltage, and can resist strong acid and strong alkali corrosion. After electrolyte immersion, the volume change rate is less than 35%, the mass change rate is less than 20%, and the service life is longer.

[0039] The second sealing structure is composed of the battery cover plate 100 and the sealing cover 400. Referring to FIG. 2, in the present embodiment, the side of the battery cover plate 100 away from the electrolyte is provided with a receiving groove 120, and the receiving groove 120 is coaxial with the liquid injection hole 110 and communicates with each other. The sealing cover 400 is arranged in the receiving groove 120, and the projection of the sealing cover 400 on the battery cover plate 100 in the axial direction of the liquid injection hole 110 completely covers the liquid injection hole 110 and the sealing spike 300. The sealing cover 400 is welded to the side wall 122 of the receiving groove 120 and forms a second sealing surface at the welding position. The axial direction of the liquid injection hole 110 is the Y-axis direction shown in FIG. 2. Thus, the gap between the sealing cover 400 and the side wall 122 of the receiving groove 120 can be blocked by the second sealing surface between the sealing cover 400 and the battery cover plate 100, further preventing the electrolyte from leaking, and the sealing effect is better.

[0040] Referring to FIGS. 1 and 4, in the present embodiment, the sealing spike 300 includes a sealing portion 310 and a liquid injection portion 320. Before the electrolyte is injected, the liquid injection portion 320 of the sealing spike 300 can be pre-installed into the liquid injection hole 110, and after the electrolyte is injected, the sealing portion 310 of the sealing spike 300 is pressed into the liquid injection hole 110 by a pressing device, at which time the sealing portion 310 of the sealing spike 300 is located at the same level as the liquid injection hole 110. The diameter of the sealing portion 310 of the sealing spike 300 is D, and the compression rate of the sealing portion 310 in the radial direction is Ψ, and the value of Ψ ranges from 5.08% to 10.6%. The radial direction of the sealing portion 310 is the X-axis direction in FIG. 1.

[0041] The arc-shaped chamfer 130 is protruded towards the direction where the sealing nail 300 is located. By arranging the arc-shaped chamfer 130, on one hand, the sealing part 310 of the sealing nail 300 can be more easily pressed into the liquid injection hole 110; on the other hand, the arc-shaped chamfer 130 can also form a space for giving way, and some space is reserved for the deformation of the sealing nail 300, so as to avoid the deviation of the sealing nail 300 when the pressing equipment is pressed into the sealing nail 300, and the axial direction of the sealing nail 300 is ensured to be the same as the axial direction of the liquid injection hole 110, that is, the axial direction of the sealing nail 300 is along the Y-axis direction.

[0042] In some embodiments, the radius of the arc-shaped chamfer 130 is r, and the value of r is in the range of 0.1 mm-0.5 mm. For example, the radius r of the arc-shaped chamfer 130 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm, and the like. The radius r of the arc-shaped chamfer 130 should not be too small, and the space for giving way is small when r is too small, and the guiding effect is not obvious; the radius r of the arc-shaped chamfer 130 should not be too large, and the contact surface between the sealing part 310 of the sealing nail 300 and the inner wall of the liquid injection hole 110 is small when r is too large, that is, the area of the first sealing surface is small, and the sealing effect is reduced, which cannot meet the sealing requirement. In some embodiments, the arc-shaped chamfer 130 can also be replaced by a reverse tapered chamfer.

[0043] In the embodiment, the height of the liquid injection hole 110 along the axial direction of the liquid injection hole 110 is H, and the height of the first sealing surface along the axial direction of the liquid injection hole 110 is H1. The height of the first sealing surface is the effective sealing height between the liquid injection hole 110 and the sealing part 310 of the sealing nail 300, and the effective sealing height is also H1. Due to the existence of the arc-shaped chamfer 130, H1 is less than H. Optionally, the value of H is in the range of 0.6 mm-2.0 mm, and the value of H1 is in the range of 0.5 mm-1.5 mm. For example, when H is 0.6 mm, r can be 0.1, and H1 is 0.5 mm. When H is 2.0 mm, r can be 0.5 mm, and H1 is 1.5 mm. In this way, the area of the first sealing surface is ensured to be large enough, and the sealing performance of the liquid injection hole 110 is good. It should be noted that the height H of the liquid injection hole 110 is equal to the sum of the height H1 of the first sealing surface and the radius r of the arc-shaped chamfer 130, that is, H=H1+r. The value of r can be adjusted in time according to the height H of the liquid injection hole 110 and the sealing requirement.

[0044] Referring to FIG. 2 and FIG. 5, after the sealing nail 300 and the battery cover plate 100 are installed, the sealing cover 400 can be installed in the accommodating groove 120 of the battery cover plate 100. Among them, the height of the battery cover plate 100 along the axial direction of the liquid injection hole 110 is A, and the value range of A is 1.5mm-3mm, except the position where the liquid injection hole 110 is arranged. The depth of the accommodating groove 120 along the axial direction of the liquid injection hole 110 is B, and the value range of B is 0.9mm-1.3mm. For example, when the height A of the battery cover plate 100 is set to 1.5mm, the depth B of the accommodating groove 120 is 0.9mm. When the height A of the battery cover plate 100 is set to 3mm, the depth of the accommodating groove 120 is 1.3mm. The height A of the battery cover plate 100 and the depth B of the accommodating groove 120 can also be set to other values within the above range, which will not be listed one by one here.

[0045] After the sealing cover 400 is installed in the accommodating groove 120 and welded with the side wall 122 of the accommodating groove 120, the end face of the sealing cover 400 away from the electrolyte is not higher than the end face of the battery cover plate 100 away from the electrolyte. Alternatively, the distance between the end face of the sealing nail 300 away from the electrolyte and the end face of the battery cover plate 100 away from the electrolyte is b, and the value range of b is 0.1mm-0.5mm. For example, b can be 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm, etc. Through the above setting, the sealing cover 400 is completely embedded in the accommodating groove 120, which can reduce the occupied space of the battery cover plate 100 after assembly on the one hand, and on the other hand, it also avoids that the sealing cover 400 protrudes from the end face of the battery cover plate 100 away from the electrolyte, and is affected by the connection strength between the sealing cover 400 and the battery cover plate 100.

[0046] As an optional solution, the sealing cover 400 in the embodiment includes a shielding part 410, a buffer part 420 and a welding part 430, wherein the buffer part 420 is arranged in the circumferential direction of the shielding part 410, the welding part 430 is arranged in the circumferential direction of the buffer part 420, and the shielding part 410, the buffer part 420 and the welding part 430 are all located in the accommodating groove 120, that is, the height of the shielding part 410, the buffer part 420 and the welding part 430 is less than the depth B of the accommodating groove 120. The projection of the shielding part 410 on the battery cover plate 100 along the axial direction of the liquid injection hole 110 completely covers the liquid injection hole 110 and the sealing nail 300, and the welding part 430 is welded and connected with the side wall 122 of the accommodating groove 120. By arranging the buffer part 420, the welding stress can be effectively relieved, so that the welding strength when the welding part 430 is welded with the side wall 122 of the accommodating groove 120 is higher, the welding quality is good, and the sealing effect of the second sealing surface formed at the welding position is good.

[0047] Exemplarily, the weld depth of the welding portion 430 after being welded with the side wall 122 of the accommodation groove 120 is h, and the weld width is w. h is in the range of 0.5mm-1.5mm, and w is in the range of 0.5mm-1.0mm. For example, h can be 0.5mm, 0.8mm, 1.0mm, 1.2mm or 1.5mm, etc. w can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm, etc.

[0048] Referring to FIGS. 2 and 3, the side wall 122 of the accommodation groove 120 in the embodiment is obliquely arranged, and the included angle between the side wall 122 of the accommodation groove 120 and the bottom wall 121 of the accommodation groove 120 is a. By adopting the above arrangement, on the one hand, the side wall 122 of the accommodation groove 120 can play a certain guiding role when the sealing cover 400 is installed, facilitating the sealing cover 400 to be installed into the accommodation groove 120 and being conducive to rapid assembly; on the other hand, the oblique side wall 122 can improve the welding yield when the sealing cover 400 is welded with the battery cover plate 100, and ensure that the connection strength at the welding position is high and the sealing effect is good. Exemplarily, a is in the range of 95°-175°. For example, a can be 95°, 100°, 120°, 130°, 150°, 160° or 175°, etc.

[0049] The outer peripheral surface of the welding portion 430 is obliquely arranged, and the included angle between the outer peripheral surface of the welding portion 430 and the bottom wall 121 of the accommodation groove 120 is β, 0°≤β-a≤5°. That is, the oblique angle of the outer peripheral surface of the welding portion 430 is greater than the oblique angle of the bottom wall 121 of the accommodation groove 120. In the embodiment, the diameter of the sealing cover 400 is greater than the diameter of the accommodation groove 120, so that the sealing cover 400 and the side wall 122 of the accommodation groove 120 are in interference fit, so that the contact between the sealing cover 400 and the battery cover plate 100 is more close, and the sealing effect of the second sealing surface is better. In addition, the sealing cover 400 is made of a rigid material, such as aluminum metal or aluminum alloy material, and the deformation amount of the sealing cover 400 in the radial direction (X-axis direction in FIG. 2) is small, so the interference amount between the sealing cover 400 and the side wall 122 of the accommodation groove 120 should not be too large.

[0050] Continuing to refer to FIG. 2, at least part of the sealing cover 400 protrudes away from the sealing nail 300, and an avoiding space 4101 is formed at the protruding part. The avoiding space 4101 is opposite to the sealing nail 300, and can avoid the end portion of the sealing nail 300 away from the electrolyte, that is, the avoiding space 4101 can avoid the sealing portion 310 of the sealing nail 300, so as to form a gap between the sealing portion 310 of the sealing nail 300 and the sealing cover 400, and avoid the sealing nail 300 and the sealing cover 400 having interaction force therebetween, affecting the welding quality, and further causing the connection strength between the sealing cover 400 and the battery cover plate 100 to decrease.

[0051] In some embodiments, the shielding portion 410 of the sealing cover 400 can be protruded away from the sealing spike 300, the buffer portion 420 abuts against the bottom wall 121 of the accommodating groove 120, and thus a clearance space 4101 is formed at the center of the shielding portion 410, the diameter of the clearance space 4101 is greater than the diameter of the sealing portion 310, so that the clearance space 4101 can accommodate the sealing portion 310. In addition, in some embodiments, the shielding portion 410 of the sealing cover 400 can be protruded away from the sealing spike 300, the buffer portion 420 has a gap with the bottom wall 121 of the accommodating groove 120, the diameter of the clearance space 4101 is greater than the diameter of the sealing portion 310, and because the buffer portion 420 has a gap with the bottom wall 121 of the accommodating groove 120, the volume of the clearance space 4101 is greater.

[0052] The present embodiment also provides a battery, as shown in FIG. 6, which can be a square battery. The square battery includes a battery cover plate 100, a shell 200, and a battery cell 500. The battery cell 500 is arranged in the shell 200, and the battery cover plate 100 is snap-fitted and welded to the shell 200. The battery cover plate 100 is provided with a liquid injection hole 110, which is sealed by the battery liquid injection hole sealing structure described above. For example, the liquid injection hole 110 is pressed into the elastically deformable sealing spike 300, and the circumferential accommodating groove 120 of the liquid injection hole 110 is provided with the rigid sealing cover 400 with a small deformation amount, so as to increase the reliability of the sealing of the liquid injection hole 110 by two layers of sealing structures.

[0053] In addition, the compression rate of the sealing spike 300 in the radial direction of the sealing spike 300 is controlled to be in the range of 5.08%-10.6%, so that the sealing effect between the sealing spike 300 and the liquid injection hole 110 is good, and at the same time, the sealing spike 300 can be smoothly pressed into the liquid injection hole 110 by the pressing equipment, without damaging the battery cover plate 100.

[0054] In some embodiments, the battery can also be a blade battery. As shown in FIG. 7, the blade battery also includes a battery cover plate 100, a shell 200, and a battery cell 500. The battery cell 500 is arranged in the shell 200, and the battery cover plate 100 is snap-fitted and welded to the shell 200. The battery cover plate 100 is provided with a liquid injection hole 110, which is sealed by the battery liquid injection hole sealing structure described above. For example, the liquid injection hole 110 is pressed into the elastically deformable sealing spike 300, and the circumferential accommodating groove 120 of the liquid injection hole 110 is provided with the rigid sealing cover 400 with a small deformation amount, so as to increase the reliability of the sealing of the liquid injection hole 110 by two layers of sealing structures.

[0055] The following describes the pre-assembly of sealing spikes 300 and battery cover plates 100 of different size specifications that meet the size range requirements described above, and the helium detection and pressure resistance test of the pre-assembled battery cover plates 100, and the results are shown in Table 1.

[0056] Table 1

[0057] By pre-assembling the sealing peg 300 and the battery cover plate 100 of the above size specifications and performing helium detection, it is found that when the inner diameter d of the liquid injection hole 110, the diameter D of the sealing peg 300, the compression rate Ψ, the height H1 of the first sealing surface (i.e. the effective sealing height), and the height H of the liquid injection hole all meet the above requirements, the sealing effect of the first layer sealing structure of each sample of the embodiment is good, the pressure resistance value can reach 0.9 MPa, and the helium leak rate value is below 1 x 10 -6 pa·m 3 / s, meeting the sealing requirements. In addition, the compression rate Ψ of the sealing peg 300 meets the value range of 5.08%-10.6%, and the pegging equipment can easily press the sealing peg 300 into the liquid injection hole 110, and the pressure of the pegging equipment pressing the sealing peg 300 is 1000N-1500N.

[0058] The sealing peg 300 and the battery cover plate 100 of other different size specifications that do not meet the above size range requirements are pre-assembled, and the battery cover plate 100 after pre-assembly is subjected to helium detection and pressure resistance test, and the results are shown in Table 2.

[0059] Table 2

[0060] By pre-assembling the sealing peg 300 and the battery cover plate 100 of the above size specifications and performing helium detection and pressure resistance test, it is found that each sample in the above comparative examples has poor sealing or encounters difficulties in assembly and production.

[0061] For example, in sample 1, sample 2 and sample 3, although the height H1 of the first sealing surface (i.e. the effective sealing height) meets the value range of 0.5mm-1.5mm, the compression rate Ψ is lower than the minimum value of the value range of 5.08%-10.6%, although the pegging equipment can easily press the sealing peg 300 into the liquid injection hole 110, the helium leak rate value is below 1 x 10

[0062] In sample 4, sample 5, sample 6 and sample 7, although the height H1 of the first sealing surface meets the value range of 0.5mm-1.5mm, the compression rate Ψ is higher than the maximum value of the value range of 5.08%-10.6%, although the helium leak rate value is below 1 x 10 -6 pa·m 3below, but the pressure resistance is poor, and when the pressure value exceeds 0.9 MPa, the sealing nail 300 is easily pulled out of the liquid injection hole 110, and the product is defective.

[0063] In samples 8 and 9, the compression rate Ψ of samples 8 and 9 is less than the minimum value of the value range 5.08%-10.6%, and the height H1 of the first sealing surface is lower than the minimum value of the value range 0.5mm-1.5mm, although the nail pressing equipment can easily press the sealing nail 300 into the liquid injection hole 110, the helium leak rate value is 1x10 - 7 pa·m 3 below, but the pressure resistance is poor, and when the pressure value exceeds 0.9 MPa, the sealing nail 300 is easily pulled out of the liquid injection hole 110, and the product is defective.

[0064] In sample 10, the compression rate Ψ of sample 10 meets the value range 5.08%-10.6%, but the height H1 of the first sealing surface is lower than the minimum value of the value range 0.5mm-1.5mm, although the nail pressing equipment can easily press the sealing nail 300 into the liquid injection hole 110, the helium leak rate value is 1x10 -7 pa·m 3 below, but the pressure resistance is poor, and when the pressure value exceeds 0.9 MPa, the sealing nail 300 is easily pulled out of the liquid injection hole 110, and the product is defective.

[0065] In samples 11 and 12, the height H1 of the first sealing surface is higher than the maximum value of the value range 0.5mm-1.5mm, and the compression rate Ψ meets the value range 5.08%-10.6%, and the helium leak rate value is 1x10 -6 pa·m 3 below, and meets the helium detection requirements, and the pressure resistance value can reach 0.9 MPa, meeting the sealing requirements. However, this requires increasing the height H of the liquid injection hole 110 of the battery cover plate 100, which exceeds 2mm, and the manufacturing process in the related art is not easy to manufacture, and difficulties are encountered when processing the liquid injection hole 110, and the product may have a processing problem. In addition, the increase in the height H of the liquid injection hole 110 also means that the height A of the battery cover plate 100 needs to be increased, resulting in an increase in the weight of the battery cover plate 100, an increase in cost, and a decrease in space utilization.

[0066] In summary, when the size specifications of the sealing spike 300 and the battery cover plate 100 meet the required values of the diameter D of the sealing spike 300, the inner diameter d of the liquid injection hole 110, the compression rate Ψ, the height H1 of the first sealing surface, and the height H of the liquid injection hole, the sealing effect of the liquid injection hole 110 can be basically guaranteed to be good, the pressure resistance value meets the requirements, and the assembly is easy.

[0067] The second layer sealing structure is also included in the present embodiment. After the sealing spike 300 and the sealing cover 400 are both assembled with the battery cover plate 100, helium detection and pressure resistance testing are performed. The helium leakage rate is less than 1x10 -8 pa·m 3 The pressure resistance value can reach 1.2 MPa, and the sealing performance and pressure resistance strength are both improved, and the safety performance of the battery is better.

[0068] Note that in the description of the present specification, the description referring to the terms "some embodiments", "other embodiments", and the like means that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. The illustrative expressions of the above terms in the present specification do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A battery electrolyte injection hole sealing structure, comprising: a battery cover plate (100) provided with an electrolyte injection hole (110) configured to inject electrolyte into a housing (200) of a battery, the battery cover plate (100) being provided on a side facing away from the electrolyte with a receiving groove (120) coaxial with and in communication with the electrolyte injection hole (110); a sealing pin (300) made of fluororubber, the sealing pin (300) being disposed in the electrolyte injection hole (110) and in interference fit with an inner wall of the electrolyte injection hole (110), a first sealing surface being formed between the sealing pin (300) and the inner wall of the electrolyte injection hole (110); the compression rate of the sealing pin (300) in the radial direction of the electrolyte injection hole (110) being Ψ, and the value of Ψ being in the range of 5.08% to 10.6%; a sealing cover (400) disposed in the receiving groove (120), the sealing cover (400) comprising a shielding portion (410), a buffer portion (420) and a welding portion (430), the buffer portion (420) being disposed in the circumferential direction of the shielding portion (410), the welding portion (430) being disposed in the circumferential direction of the buffer portion (420), a projection of the shielding portion (410) on the battery cover plate (100) in the axial direction of the electrolyte injection hole (110) completely covering the electrolyte injection hole (110) and the sealing pin (300), the welding portion (430) being welded to a side wall (122) of the receiving groove (120) and forming a second sealing surface at the welding portion (430); the side wall (122) of the receiving groove (120) being inclined, an included angle between the side wall (122) of the receiving groove (120) and a bottom wall (121) of the receiving groove (120) being α, and the value of α being in the range of 95° to 175°; an outer circumferential surface of the welding portion (430) being inclined, an included angle between the outer circumferential surface of the welding portion (430) and the bottom wall (121) of the receiving groove (120) being β, and 0°≤β-α≤5°.

2. The battery filling hole sealing structure according to claim 1, wherein an arc-shaped chamfer (130) being provided at one end of the electrolyte injection hole (110) in communication with the receiving groove (120), the arc-shaped chamfer (130) being convex in the direction of the sealing pin (300), a radius of the arc-shaped chamfer (130) being r, and the value of r being in the range of 0.1 mm to 0.5 mm.

3. The battery vent hole sealing structure according to claim 1, wherein a height of the electrolyte injection hole (110) in the axial direction of the electrolyte injection hole (110) being H, and a height of the first sealing surface in the axial direction of the electrolyte injection hole (110) being H1; the value of H being in the range of 0.6 mm to 2.0 mm, and the value of H1 being in the range of 0.5 mm to 1.5 mm.

4. The battery vent hole sealing structure according to claim 1, wherein a height of the battery cover plate (100) in the axial direction of the electrolyte injection hole (110) being A, and the value of A being in the range of 1.5 mm to 3 mm; a depth of the receiving groove (120) in the axial direction of the electrolyte injection hole (110) being B, and the value of B being in the range of 0.9 mm to 1.3 mm. After the sealing cover (400) is mounted to the accommodating groove (120), the end face of the sealing cover (400) away from the electrolyte is not higher than the end face of the battery cover plate (100) away from the electrolyte, and the distance between the end face of the sealing nail (300) away from the electrolyte and the end face of the battery cover plate (100) away from the electrolyte is b, and the value range of b is 0.1mm-0.5mm.

5. The battery vent hole sealing structure according to claim 1, wherein The penetration depth of the welding part (430) and the side wall (122) of the accommodating groove (120) after welding is h, and the width is w, the value range of h is 0.5mm-1.5mm, and the value range of w is 0.5mm-1.0mm.

6. The battery vent hole sealing structure according to claim 1, wherein At least part of the sealing cover (400) is convex in the direction away from the sealing nail (300) and forms an avoiding space (4101). 7.A battery comprising a battery cover plate (100), a shell (200) and an electric core (500), the electric core (500) is arranged in the shell (200), the battery cover plate (100) is connected with the shell (200) by buckling and welding, the battery cover plate (100) is provided with a liquid injection hole (110), and the liquid injection hole (110) is sealed by the battery liquid injection hole sealing structure in any one of claims 1-6.

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