Power battery, battery cover plate assembly and liquid injection hole sealing structure

Abstract

The utility model discloses a power battery, a battery cover plate assembly and a liquid injection hole sealing structure. The liquid injection hole sealing structure comprises a cover plate and a sealing nail, a liquid injection hole is formed in the cover plate, and the sealing nail is arranged in the liquid injection hole and is in clearance fit with the liquid injection hole. The sealing nail comprises a first end face facing the liquid injection hole, a second end face deviating from the liquid injection hole and a first peripheral wall connecting the first end face and the second end face, the first peripheral wall is provided with at least one deformation part, the deformation part is filled between the first peripheral wall and the side wall of the liquid injection hole, and the first peripheral wall and the side wall of the liquid injection hole are welded in the whole periphery mode. According to the power battery, the battery cover plate assembly and the liquid injection hole sealing structure, design allowance is reserved for size fluctuation control of the sealing nail, the production requirement of the sealing nail is lowered, meanwhile, the assembling process is simple, and the situation that welding and assembling cannot be conducted is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a power battery, a battery cover assembly and a liquid injection hole sealing structure. Background Art

[0002] Due to the advantages of power batteries (such as lithium-ion batteries) such as high energy density, high power density, many cycles and long storage time, they have been widely used in portable electronic devices such as mobile phones, digital cameras and laptops, and have broad application prospects in electric vehicles such as electric vehicles and electric bicycles and large and medium-sized electric equipment such as energy storage facilities.

[0003] The battery top cover assembly of the power battery is formed with an injection hole for injecting electrolyte into the battery. A sealing structure that matches the injection hole is provided at the injection hole to prevent the electrolyte in the battery from flowing out of the battery and thus damaging the battery. In the related art, the sealing structure includes a sealing glue nail and a sealing aluminum nail. After the power battery is injected with electrolyte, the injection hole is sealed with a sealing glue nail, and then the injection hole is sealed with a sealing aluminum nail, and then the sealing aluminum nail is laser welded to the top cover.

[0004] In actual production, since the assembly of the sealing aluminum nails and the injection holes has very strict requirements on the size adaptability, if there is a deviation in the size of the sealing aluminum nails, the sealing aluminum nails cannot be welded if the size is too small, and the aluminum nails cannot be assembled if the size is too large. The production requirements of the sealing aluminum nails are high and the assembly is difficult. Utility Model Content

[0005] Based on this, it is necessary to provide a power battery, a battery cover assembly and a liquid injection hole sealing structure to address the problems of the existing power battery liquid injection hole sealing structure, high production requirements and difficult assembly of sealing aluminum nails.

[0006] A liquid injection hole sealing structure, comprising:

[0007] A cover plate, wherein a liquid injection hole is formed on the cover plate; and

[0008] A sealing pin is arranged in the injection hole and is gap-matched with the injection hole. The sealing pin includes a first end face facing the injection hole and a second end face away from the injection hole, and a first circumferential wall connecting the first end face and the second end face. The first circumferential wall is provided with at least one deformation portion, and the deformation portion is filled between the first circumferential wall and the side wall of the injection hole. The first circumferential wall and the side wall of the injection hole are welded around the entire circumference.

[0009] In one embodiment, the second end surface of the sealing pin is provided with a cavity extending toward the first end surface.

[0010] In one of the embodiments, the first end surface of the sealing pin is provided with a convex bump corresponding to the cavity and protruding into the battery.

[0011] In one embodiment, the cavity and the convex hump are arranged on the axis of the sealing pin.

[0012] In one embodiment, the surface of the cavity is a spherical surface, and the surface of the convex hull is a spherical surface.

[0013] In one embodiment, the deformation portion and the sealing pin are integrally formed.

[0014] In one embodiment, it also includes a sealing nail, the injection hole includes a first hole and a second hole, the aperture of the first hole is smaller than the aperture of the second hole, the sealing nail is arranged in the first hole, and the sealing nail is arranged in the second hole.

[0015] In one of the embodiments, there is a gap between the sealing nail and the sealing glue nail in the axial direction of the battery.

[0016] A battery cover assembly comprises any one of the above-mentioned liquid injection hole sealing structures.

[0017] A power battery comprises the battery cover assembly described above.

[0018] The above-mentioned power battery, battery cover assembly and liquid injection hole sealing structure have at least the following advantages:

[0019] The sealing pin and the injection hole are designed to have a clearance fit, and the first peripheral wall of the sealing pin is provided with at least one deformation part. During assembly, the sealing pin is pushed into the injection hole using a tool, and the deformation part is deformed and filled between the first peripheral wall and the side wall of the injection hole, so that the sealing pin and the injection hole are clamped together. Therefore, the sealing pin will not move during the subsequent welding process, and then it is assembled by laser welding. Therefore, there is a design margin for the control of the fluctuation of the size of the sealing pin, which reduces the production requirements of the sealing pin. At the same time, the assembly process is simple, and there will be no situation where welding and assembly cannot occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation of the utility model, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0021] Figure 1 is a schematic diagram of the structure of a power battery in one embodiment;

[0022] Figure 2 for Figure 1 A schematic diagram of the structure of the battery cover assembly;

[0023] Figure 3 for Figure 2 Schematic diagram of the connection between the middle sealing pin and the injection hole;

[0024] Figure 4 for Figure 3 Schematic diagram of the structure of the middle sealing nail;

[0025] Figure 5 for Figure 4 A front view of the sealing nail shown;

[0026] Figure 6 for Figure 4 A cross-sectional view of the sealing pin shown;

[0027] Figure 7 for Figure 2 A cross-sectional view of the battery cover assembly shown;

[0028] Figure 8 for Figure 7 A partial enlarged view of point A in the middle.

[0029] Reference numerals:

[0030] 10-shell, 20-battery cover assembly, 21-cover, 212-liquid injection hole, 212a-first hole, 212b-second hole, 22-sealing nail, 221-first end surface, 222-second end surface, 223-first peripheral wall, 224-deformation part, 225-cavity, 226-convex bump, 23-sealing glue nail. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation of the utility model is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific implementation disclosed below.

[0032] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right guide" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0034] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0035] The power battery includes a shell, a top cover and a cell assembly. The cell assembly is accommodated in the shell, and the top cover is closed on the shell to seal the electrode assembly inside the shell. Among them, the top cover is provided with a liquid injection port, through which electrolyte is injected into the shell so that the electrolyte can infiltrate the electrode assembly.

[0036] After the electrolyte is injected, the injection port needs to be sealed by welding with a sealing nail to form a sealed space inside the shell. However, in actual production, since the assembly of the sealing aluminum nail and the injection hole has strict requirements on the size adaptability, if the size of the sealing aluminum nail deviates, the sealing aluminum nail cannot be welded if it is too small, and it cannot be assembled if it is too large. The production requirements of the sealing aluminum nail are high and the assembly is difficult.

[0037] In view of this, in order to solve the above problems, the present application provides a liquid injection hole sealing structure, and the surrounding wall of the sealing pin is designed with a deformation part. When assembling the cover plate, the sealing pin is first hit into the liquid injection hole using a tooling, and the deformation of the deformation part is relied on to achieve a tight fit. The sealing aluminum pin will not move during the welding process, and then it is assembled by laser welding.

[0038] In order to better understand the technical solutions and beneficial effects of the present application, the present application is further described in detail below in conjunction with specific embodiments:

[0039] See also Figure 1 A power battery in one embodiment includes a shell 10, a battery cell assembly and a battery cover assembly 20. The upper end of the shell 10 has an opening, and the battery cell assembly is loaded into the shell 10 through the opening. The battery cover assembly 20 is connected to the shell 10 and blocks the opening of the shell 10 to achieve sealing of the power battery.

[0040] Please also read Figure 2The battery cover assembly 20 includes a liquid injection hole sealing structure, and the liquid injection hole sealing structure includes a cover 21 and a sealing nail 22. Among them, the cover 21 is a sheet of material with a sheet structure. Its specific structure is not fixed, and its applicability is adjusted according to the specific design structure of different batteries. For example, the cover 21 can be a narrow strip / long strip structure, or it can also be made into a square or round shape, etc. The material of the cover 21 can be made of metal material, such as steel sheet, aluminum sheet, etc., and alloy or composite plastic can also be used as the cover 21, which is not limited here.

[0041] Please also read Figure 3 A liquid injection hole 212 is formed on the cover plate 21, and the liquid injection hole 212 penetrates two opposite surfaces of the cover plate 21 along the thickness direction of the cover plate 21. One end of the liquid injection hole 212 is connected to the interior of the shell 10, and the other end of the liquid injection hole 212 is connected to the external space of the power battery. Therefore, electrolyte can be injected into the shell 10 from the outside of the power battery through the liquid injection hole 212.

[0042] Please also read Figure 4 The sealing nail 22 is arranged in the injection hole 212, and the sealing nail 22 and the injection hole 212 are matched with each other in a clearance, that is, after the sealing nail 22 is installed in the injection hole 212, there is a clearance between the sealing nail 22 and the side wall of the injection hole 212. The sealing nail 22 includes a first end face 221 facing the injection hole 212 and a second end face 222 facing away from the injection hole 212, and a first peripheral wall 223 connecting the first end face 221 and the second end face 222. Specifically, when the sealing nail 22 is installed, the first end face 221 is located inside the battery, and the second end face 222 is exposed to the outside.

[0043] The first circumferential wall 223 is provided with at least one deformation portion 224. When the sealing pin 22 is assembled, the sealing pin 22 is pushed into the injection hole 212 by using a tool, and the deformation portion 224 is deformed and filled between the first circumferential wall 223 and the side wall of the injection hole 212, so as to realize the clamping connection between the sealing pin 22 and the injection hole 212. Therefore, the sealing pin 22 will not move during the subsequent welding process. After that, laser welding is used for assembly, and the first circumferential wall 223 and the side wall of the injection hole 212 are welded around the entire circumference to realize the sealing of the injection hole 212.

[0044] In this embodiment, the number of the deformation part 224 is one, which can reduce the processing steps and difficulty of the sealing nail 22. It can be understood that in other embodiments, the number of the deformation part 224 can also be multiple, and the multiple deformation parts 224 are evenly or unevenly distributed in the circumferential direction of the first peripheral wall 223. The support of the multiple deformation parts 224 can keep the sealing nail 22 centered in the injection hole 212.

[0045] In one embodiment, the sealing pin 22 may be made of aluminum, aluminum alloy, or other aluminum-based metals. Of course, in other embodiments, the sealing pin 22 may also be made of other metal materials or alloys, as long as it can be welded with the cover plate 21 to seal the injection hole 212 .

[0046] In one embodiment, the sealing pin 22 can be made by a stamping process, and the deformation portion 224 on the first peripheral wall 223 can be integrally formed with the sealing pin 22 , that is, the deformation portion 224 is stamped out during the stamping process, thereby reducing the processing steps of the sealing pin 22 .

[0047] Of course, in other embodiments, the deformation portion 224 on the first peripheral wall 223 can also be stamped in steps with the sealing pin 22, such as stamping the sealing pin 22 before stamping the deformation portion 224. Alternatively, after the sealing pin 22 is stamped, the deformation portion 224 is formed on the first peripheral wall 223 by other methods, such as welding the deformation portion 224 to the first peripheral wall 223.

[0048] Please also read Figure 5 and Figure 6 In one embodiment, the second end face 222 of the sealing pin 22 is provided with a cavity 225 extending toward the first end face 221. When the sealing pin 22 is installed in the injection hole 212 for welding, the cavity 225 on the second end face 222 extending toward the first end face 221 can release welding thermal stress, reduce welding defects caused by thermal deformation, alleviate deformation of the sealing pin 22, and ensure welding quality.

[0049] The conventional sealing pin 22 is designed with a boss structure to release stress during welding, but the structure is complex, which wastes costs in mold development and production. In this embodiment, a cavity 225 is formed on the second end face 222 to release welding thermal stress, which has a simple structure and a simple mold required for production and preparation, thereby achieving cost reduction.

[0050] In one embodiment, the first end face 221 of the sealing nail 22 is provided with a convex hump 226 protruding into the battery corresponding to the cavity 225, that is, the first surface of the sealing nail 22 has a convex structure extending inward to adapt to the cavity 225. The convex hump 226 can avoid excessive thickness difference of the sealing nail 22 when the cavity 225 is designed on the first end face 221 of the sealing nail 22, thereby avoiding uneven welding deformation of the sealing nail 22 and ensuring welding quality. At the same time, the processing difficulty of the sealing nail 22 can be reduced. Specifically, the cavity 225 of the second end face 222 of the sealing nail 22 and the convex hump 226 of the first end face 221 can be formed by one stamping, that is, after the sealing nail 22 is stamped, it is stamped from the second end face 222 to the first end face 221 through a stamping die, so that the cavity 225 and the convex hump 226 can be formed at one time.

[0051] In one embodiment, the cavity 225 and the convex hull 226 are arranged on the axis of the sealing pin 22, that is, the cavity 225 and the convex hull 226 are located at the center of the sealing pin 22, which can ensure that the cavity 225 releases the welding thermal stress uniformly, thereby ensuring the uniform welding thermal deformation of the sealing pin 22 and ensuring the welding quality. Furthermore, the surface of the cavity 225 is a spherical surface, the surface of the convex hull 226 is a spherical surface, and the surface of the cavity 225 and the surface of the convex hull 226 are smooth surfaces without ridges, which can ensure the uniform release of thermal stress and avoid uneven thermal deformation of the sealing pin 22.

[0052] Please also read Figure 7 and Figure 8 In one embodiment, the injection hole sealing structure further includes a sealing nail 23. The injection hole 212 is a stepped hole. The injection hole 212 includes a first hole 212a and a second hole 212b. The aperture of the first hole 212a is smaller than the aperture of the second hole 212b. The first hole 212a penetrates the surface of the cover plate 21 located inside the battery, and the second hole 212b penetrates the surface of the cover plate 21 located outside the battery. The sealing nail 23 is arranged in the first hole 212a, and the sealing nail 22 is arranged in the second hole 212b.

[0053] The sealing nail 23 can achieve the first layer of sealing of the injection hole 212, preventing the electrolyte in the housing 10 from flowing out of the injection hole 212, and ensuring the airtightness of the power battery. Then, the sealing nail 22 can achieve the second layer of sealing of the injection hole 212, further ensuring the airtightness of the power battery, and the sealing nail 22 can also protect the sealing nail 23 below it.

[0054] In one embodiment, the sealing nail 23 can be made of elastic components such as rubber, and the sealing nail 23 and the first hole 212a are interference fit to improve the sealing of the injection hole 212. In other embodiments, the sealing nail 23 can also be made of other non-elastic materials that can be used to achieve the sealing of the first hole 212a.

[0055] In one embodiment, there is a gap between the sealing nail 22 and the sealing glue nail 23 in the axial direction of the battery, so as to separate the sealing nail 22 and the sealing glue nail 23, thereby preventing the welding heat of the sealing nail 22 from being directly transferred to the sealing glue nail 23 during the welding process, causing the sealing glue nail 23 to be deformed and damaged by the heat, thereby causing problems with the sealing of the power battery.

[0056] The above-mentioned power battery, battery cover assembly 20 and injection hole sealing structure, the size fluctuation control of the sealing nail 22 leaves a design margin, which reduces the production requirements of the sealing nail 22, and the assembly process is simple, and there will be no situation where welding and assembly cannot be performed. The sealing nail 22 is designed with a cavity 225 and a convex hull 226 structure, which can release welding thermal stress, alleviate the deformation of the sealing nail 22, ensure welding quality, and has a simple structure. The mold required for production and preparation is simple, which can achieve cost reduction.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A liquid injection hole sealing structure, characterized in that: include: A cover plate, wherein a liquid injection hole is formed on the cover plate; and A sealing pin is arranged in the injection hole and is gap-matched with the injection hole. The sealing pin includes a first end face facing the injection hole and a second end face away from the injection hole, and a first circumferential wall connecting the first end face and the second end face. The first circumferential wall is provided with at least one deformation portion, and the deformation portion is filled between the first circumferential wall and the side wall of the injection hole. The first circumferential wall and the side wall of the injection hole are welded around the entire circumference.

2. The sealing structure of the injection hole according to claim 1, characterized in that: The second end surface of the sealing pin is provided with a cavity extending toward the first end surface.

3. The sealing structure of the injection hole according to claim 2, characterized in that: The first end surface of the sealing nail is provided with a convex bump corresponding to the cavity and protruding into the battery.

4. The sealing structure of the injection hole according to claim 3, characterized in that: The cavity and the convex bump are arranged on the axis of the sealing pin.

5. The sealing structure of the injection hole according to claim 3, characterized in that: The surface of the cavity is a spherical surface, and the surface of the convex hull is a spherical surface.

6. The sealing structure for the injection hole according to any one of claims 1 to 5, characterized in that: The deformation portion and the sealing nail are integrally formed.

7. The sealing structure for the injection hole according to any one of claims 1 to 5, characterized in that: It also includes a sealing glue nail, the injection hole includes a first hole and a second hole, the aperture of the first hole is smaller than the aperture of the second hole, the sealing glue nail is arranged in the first hole, and the sealing nail is arranged in the second hole.

8. The sealing structure of the injection hole according to claim 7, characterized in that: There is a gap between the sealing nail and the sealing glue nail in the axial direction of the battery.

9. A battery cover assembly, characterized in that: It comprises a liquid injection hole sealing structure as described in any one of claims 1-8.

10. A power battery, characterized in that: Comprising the battery cover assembly as described in claim 9.

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