Battery, battery pack and electric device

Abstract

The utility model relates to the technical field of battery manufacturing, and particularly discloses a battery, a battery pack and a power utilization device. The battery comprises a cover body and a shell, the cover body is welded to an opening of the shell and forms a welding seam, a reinforcing boss is arranged in a heat affected zone of the welding seam on the inner wall of the shell, and the reinforcing boss is continuously arranged along the circumferential surface of the inner wall of the shell. According to the invention, the reinforcing boss is additionally arranged in the heat affected zone, which is a certain distance away from the weld joint, of the side wall of the shell, so that the position of the side wall of the shell is thickened and reinforced, the welding strength is effectively improved, and the situation that the area is fragile and cracks before the anti-explosion valve to cause heat diffusion when the battery cell is subjected to emergencies such as thermal runaway and the like is avoided. According to the battery, the welding reliability of the cover body and the shell is improved, and the safety performance of the battery under special conditions is enhanced, so that the production yield is increased, and the production cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing, and in particular to a battery, a battery pack and an electrical device. Background Art

[0002] At present, lithium-ion batteries, as an important green energy storage method, have been widely used in smart electronic products, electric vehicles and other fields. Among them, batteries, as one of the core components of electric vehicles, are inseparable from the safety performance of electric vehicles. Therefore, in order to protect the lives and property of electric vehicle users, it is necessary to continuously improve the safety performance of batteries.

[0003] In battery manufacturing, the cell shell and the top cover are very critical parts of the cell structure. After the two are welded, they can protect the pole pieces inside the cell shell from external impact. However, in actual applications, after the top cover is welded to the opening of the cell shell, due to the influence of welding, the side wall of the cell shell will become relatively fragile in an area a certain distance from the weld, which is generally called the heat-affected zone. When the cell has an emergency such as thermal runaway, this area may crack before the explosion-proof valve, causing heat diffusion and causing more serious safety problems. Summary of the invention

[0004] The purpose of this application is to at least solve the technical problem that "after the top cover is welded to the opening of the battery cell shell, the side wall of the battery cell shell becomes relatively fragile in an area a certain distance from the weld. When the battery cell has an emergency such as thermal runaway, this area may crack before the explosion-proof valve, causing heat diffusion and causing more serious safety problems." This purpose is achieved through the following technical solutions:

[0005] In a first aspect, the present application provides a battery, comprising a cover and a shell, wherein an opening is provided at one end of the shell, the cover is welded to the opening of the shell to form a weld, and a reinforcing boss is provided on the inner wall of the shell in the heat affected zone of the weld, and the reinforcing boss is continuously arranged along the circumference of the inner wall of the shell.

[0006] In some embodiments, the reinforcing boss has a width direction, and the reinforcing boss at least covers an area on the inner wall of the shell between 3 mm and 3.5 mm away from the center of the weld along the width direction.

[0007] In some embodiments, the reinforcing boss covers the entire area on the inner wall of the shell between 2 mm and 5 mm from the center of the weld in the width direction.

[0008] In some embodiments, the reinforcing boss has a thickness direction, and a distance between the reinforcing boss and the inner wall of the shell along the thickness direction is 2 mm to 3 mm.

[0009] In some embodiments, the distance between the reinforcing boss and the inner wall of the shell along the thickness direction is 2.5 mm.

[0010] In some embodiments, a high temperature resistant pad is provided on one side of the reinforcing boss close to the opening along the width direction, the thickness of the high temperature resistant pad is less than or equal to the thickness of the reinforcing boss, and the side of the high temperature resistant pad close to the inner wall of the shell along the thickness direction contacts the inner wall of the shell.

[0011] In some embodiments, a lap groove is provided at the edge of the cover body, and the lap groove contacts the end surface of one end of the shell opening and is sealed by laser welding.

[0012] In some embodiments, the reinforcing boss is integrally formed with the housing.

[0013] In a second aspect, the present application also provides a battery pack, comprising the battery in the first aspect.

[0014] In a third aspect, the present application further provides an electrical device, comprising the battery pack in the second aspect.

[0015] The battery in the first aspect of the present application has at least the following advantages:

[0016] Specifically, the battery provided in the present application includes a cover and a shell, the cover is welded to the opening of the shell to form a weld, and a reinforcing boss is provided on the inner wall of the shell at least in a partial area at a certain distance from the weld, and the reinforcing boss is continuously arranged along the circumference of the inner wall of the shell.

[0017] The present application adds a reinforcing boss to the heat-affected zone of the shell side wall at a certain distance from the weld, thereby thickening and strengthening the shell side wall at that location, effectively improving the welding strength, and preventing the area from being fragile and cracking before the explosion-proof valve when the battery cell experiences sudden situations such as thermal runaway, causing heat diffusion. The present application improves the welding reliability between the cover and the shell, enhances the safety performance of the battery under special circumstances, thereby increasing the production yield and reducing production costs.

[0018] In addition, the reinforcing boss is arranged on the inner wall of the shell, so that it can not affect the overall size of the battery when the heat-affected zone of the side wall is thickened. Moreover, the reinforcing boss is arranged continuously along the circumference of the inner wall of the shell, leaving no safety weak points and the reinforcement range is comprehensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the structure of the housing described in the embodiment of the present application;

[0021] Figure 2 for Figure 1 A local enlarged schematic diagram at M in FIG.

[0022] Figure 3 A front cross-sectional view of a battery according to an embodiment of the present application;

[0023] Figure 4 for Figure 3 A local enlarged schematic diagram at position N in FIG.

[0024] Figure 5 A partial exploded view of the housing and the cover according to the embodiment of the present application;

[0025] Figure 6 This is a schematic diagram of the partial connection between the battery cell casing and the top cover before improvement;

[0026] Figure 7 is a graph showing the relationship between the shell hardness and the distance from the shell side wall to the weld;

[0027] Figure 8 This is a comparison chart of the battery welding strength before and after improvement.

[0028] Description of reference numerals:

[0029] Before improvement: 10. Battery cell casing; 11. Thinning step; 20. Top cover; h. Top weld.

[0030] After improvement: 1. battery; 100. shell; 110. opening; 200. cover; 210. lap groove; 300. reinforcing boss; 400. high temperature resistant pad; f. weld; Y, thickness direction; Z, width direction. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0032] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an", and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", and "have" are inclusive and therefore specify the presence of stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0033] Although the terms first, second, etc. may be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. In addition, in the description of this application, unless otherwise clearly specified and limited, the terms "set" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0034] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "outer", "end", "upper", "lower", "high", "lower", "inner", "middle", "side", "axial", "first direction", "second direction", etc. Such spatial relative terms are intended to include different orientations of the mechanism in use or operation in addition to the orientation depicted in the figure. For example, if the mechanism in the figure flips, the element described as "below other elements or features" or "below other elements or features" will then be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The mechanism may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

[0035] In order to deepen the understanding of this application solution, it is necessary to elaborate on the technical issues in detail in combination with relevant technologies. The specific contents are as follows:

[0036] At present, lithium-ion batteries, as an important green energy storage method, have been widely used in smart electronic products, electric vehicles and other fields. Among them, batteries, as one of the core components of electric vehicles, are inseparable from the safety performance of electric vehicles. Therefore, in order to protect the lives and property of electric vehicle users, it is necessary to continuously improve the safety performance of batteries.

[0037] In actual production, strategies to improve battery safety performance mainly include two aspects: (1) electrochemical system design; (2) battery cell structure design. In the current battery system with lithium iron phosphate or ternary materials as the positive electrode material and graphite as the negative electrode material, attempts to improve battery safety performance by changing the electrochemical system often result in half the effort with twice the results; in contrast, battery cell structure design is more effective and more cost-effective.

[0038] Among them, the cell shell and the top cover are very critical parts of the cell structure. After the two are welded, they can protect the pole pieces inside the cell shell from external impact. However, in battery manufacturing, after the top cover is welded to the opening of the cell shell, due to the influence of welding, the side wall of the cell shell will become relatively fragile in the area about 2mm to 5mm away from the weld mark, which is generally called the heat-affected zone. When the cell has an emergency such as thermal runaway, this area may crack before the explosion-proof valve, causing heat diffusion and causing more serious safety problems.

[0039] In addition, in the related art, reference is made to Figure 6 The inner wall of the cell casing 10 is provided with a thinning step 11 at the opening end, and the edge of the top cover 20 is in contact with and welded to the thinning step 11. The thinning step 11 will reduce the thickness of the cell casing 10 at that location, and reduce the welding strength between the cell casing 10 and the top cover 20, posing a safety hazard.

[0040] In order to solve the above technical problems, the present application provides a battery, a battery pack and an electric device. Figures 1 to 8 The embodiments of the present application are described in detail.

[0041] Reference Figures 1 to 4 In the first aspect, the present application provides a battery 1, which specifically includes a cover body 200 and a shell 100, one end of the shell 100 is provided with an opening 110, the cover body 200 is welded to the opening 110 of the shell 100 and forms a weld f, and a reinforcing boss 300 is provided on the inner wall of the shell 100 at least in a heat-affected zone at a certain distance from the center of the weld f, and the reinforcing boss 300 is continuously arranged along the circumference of the inner wall of the shell 100.

[0042] The present application adds a reinforcing boss 300 to the heat-affected zone of the side wall of the shell 100 at a certain distance from the weld, thereby thickening and strengthening the side wall of the shell 100 at this location, effectively improving the welding strength, and preventing the area from being fragile and cracking before the explosion-proof valve, resulting in heat diffusion when an emergency such as thermal runaway occurs in the battery cell. The present application improves the welding reliability between the cover 200 and the shell 100, and enhances the safety performance of the battery 1 under special circumstances, thereby increasing the production yield and reducing production costs. In addition, the reinforcing boss 300 is arranged on the inner wall of the shell 100, so that it can not affect the overall size of the battery 1 when the heat-affected zone of the side wall is thickened, and the reinforcing boss 300 is continuously arranged along the circumference of the inner wall of the shell 100, leaving no safety weaknesses, and the strengthening range is comprehensive.

[0043] In particular, generally, the area between 2 mm and 5 mm from the side wall of the shell 100 and the center of the weld f is the heat affected zone of the weld.

[0044] In some embodiments, the reinforcing boss 300 has a width direction Z, and the reinforcing boss 300 at least covers an area on the inner wall of the shell 100 between 3 mm and 3.5 mm from the center of the weld f along the width direction Z.

[0045] According to experimental analysis, we can get Figure 7 The data relationship diagram shown, specifically, Figure 7 The horizontal axis is the distance between the side wall of the shell 100 and the weld f, with a unit of "0.1 mm", and the vertical axis is the Vickers hardness, with a unit of "HV". It can be understood that the side wall strength of the shell 100 is correlated with the Vickers hardness value, so the Vickers hardness can also represent the side wall strength to a certain extent, and the Vickers hardness is easier to measure and obtain, which is convenient for the experiment.

[0046] Reference Figure 7 The hardness value of the area between 3 mm and 3.5 mm from the center of the weld f on the side wall of the shell 100 is the lowest, so this area is the weakest part of the side wall of the shell 100, so it is necessary to set a reinforcing boss 300 to cover this area.

[0047] In some embodiments, the reinforcing boss 300 covers the entire area on the inner wall of the housing 100 between 2 mm and 5 mm from the center of the weld f along the width direction Z.

[0048] In this embodiment, the reinforcing boss 300 covers the entire area on the inner wall of the shell 100 between 2 mm and 5 mm from the center of the weld f along the width direction Z, further increasing the coverage of the reinforcing boss 300 and improving the welding strength of the battery 1.

[0049] In particular, the reinforcing boss 300 may completely cover the heat affected zone, or may only cover a portion of the heat affected zone; in addition, on the premise of ensuring that it does not interfere with the internal pole group of the shell 100, the reinforcing boss 300 may also be provided in the non-heat affected zone of the inner wall of the shell 100 on the basis of covering the heat affected zone, and all of the above contents are within the scope of protection of the present application.

[0050] In some embodiments, the reinforcing boss 300 has a thickness direction Y, and the dimension of the reinforcing boss 300 in the thickness direction Y is 2 mm to 3 mm. That is, the dimension of the reinforcing boss 300 from the inner wall of the housing 100 along the thickness direction Y is 2 mm to 3 mm.

[0051] In some embodiments, the dimension of the reinforcing boss 300 in the thickness direction Y is 2.5 mm. It can be understood that the dimension of the reinforcing boss 300 from the inner wall of the housing 100 in the thickness direction Y is 2.5 mm.

[0052] It should be noted that the thickness dimension of the above reinforcing boss 300 is obtained according to actual application. The dimension of the reinforcing boss 300 in the thickness direction Y is preferably 2 mm to 3 mm, and more preferably 2.5 mm. Under this dimension, the reinforcing boss 300 can not only increase the welding strength, but also will not interfere with the pole group inside the shell 100.

[0053] In some embodiments, reference Figure 5 Along the width direction Z, a high temperature resistant pad 400 is provided on the side of the reinforcing boss 300 close to the opening, the thickness of the high temperature resistant pad 400 is less than or equal to the thickness of the reinforcing boss 300, and the side of the high temperature resistant pad 400 close to the inner wall of the shell 100 along the thickness direction Y contacts the inner wall of the shell 100.

[0054] In this embodiment, the high temperature resistant pad 400 is preferably a high temperature resistant resin, which can be bonded to the inner wall of the housing 100. The thickness of the high temperature resistant pad 400 is less than or equal to the thickness of the reinforcing boss 300, and will not interfere with the internal pole group of the housing 100, and can be supported by the reinforcing boss 300. The high temperature resistant pad 400 can not only play a role in further sealing, but also increase the strength of the side wall of the housing 100 at that location.

[0055] In some embodiments, reference Figure 4 and Figure 5 A lap groove 210 is provided on the edge of the cover body 200, and the lap groove 210 contacts the end surface of one end of the opening 110 of the shell 100 and is sealed by laser welding.

[0056] In this embodiment, further reference is made to Figure 6Compared with the battery before the improvement, the thinning step 11 is eliminated from the side wall of the shell 100, and a lap groove 210 is set at the edge of the cover 200 to overlap with the shell 100, thereby increasing the thickness of the shell 100 at this location, thereby increasing the welding strength of the shell 100 and improving the safety of the battery 1.

[0057] In addition, refer to Figure 4 and Figure 6 In the battery before the improvement, the edge of the top cover 20 contacts and welds with the thinning step 11 of the battery cell shell 10 to form a top weld h; during welding, if the laser vertical incidence is kept unchanged, the square battery needs to have a more complicated movement trajectory. In addition, in the improved battery 1, the lap groove 210 at the edge of the cover 200 contacts the end face of one end of the opening 110 of the shell 100 and is sealed by laser welding to form a side weld f; during welding, if the laser horizontal incidence is kept unchanged, the square battery only needs to be rotated, and the production efficiency is high.

[0058] In some embodiments, the reinforcing boss 300 is integrally formed with the housing 100 .

[0059] In this embodiment, the reinforcing boss 300 and the housing 100 are integrally formed by a mold, and the structure has high strength, high safety and reliability, and a simple production process. At the same time, it should be noted that the reinforcing boss 300 can also be set on the inner wall of the housing 100 by welding or bonding, which can still improve the welding strength compared to not setting the reinforcing boss 300, and also belongs to the protection scope of this application.

[0060] In practice, according to experiments, we can get Figure 8 The comparison diagram shown, specifically, Figure 8 A in the horizontal axis represents the battery before improvement, B represents the improved battery 1, and the vertical axis represents the welding strength, in "MPa". In this experiment, for the improved battery 1, the two sides of the reinforcing boss 300 in the width direction Z are 2mm and 5mm away from the center of the weld f, that is, the width of the reinforcing boss 300 is 3mm, and the thickness of the reinforcing boss 300 is 2.5mm. Figure 8 It can be seen that the improved battery 1 has a greatly improved welding strength compared to the battery before the improvement.

[0061] In a second aspect, the present application further provides a battery pack, which includes the battery 1 in the first aspect.

[0062] In a third aspect, the present application further provides an electrical device, which includes the battery pack in the second aspect.

[0063] In this embodiment, the battery pack of the second aspect and the electrical device of the third aspect both include the battery 1 of the first aspect, so the battery pack of the second aspect and the electrical device of the third aspect have at least all the technical effects of the battery 1 of the first aspect of the present application, which will not be elaborated here.

[0064] Although the embodiments of the present application are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: The invention comprises a cover body (200) and a shell (100), wherein one end of the shell (100) is provided with an opening (110), the cover body (200) is welded to the opening (110) of the shell (100) to form a weld (f), and a reinforcing boss (300) is provided on the inner wall of the shell (100) in the heat-affected zone of the weld (f), and the reinforcing boss (300) is continuously arranged along the circumference of the inner wall of the shell (100).

2. The battery according to claim 1, characterized in that The reinforcing boss (300) has a width direction (Z), and the reinforcing boss (300) at least covers an area on the inner wall of the shell (100) between 3 mm and 3.5 mm from the center of the weld (f) along the width direction (Z).

3. The battery according to claim 2, characterized in that The reinforcing boss (300) covers the entire area on the inner wall of the shell (100) between 2 mm and 5 mm from the center of the weld (f) along the width direction (Z).

4. The battery according to claim 3, characterized in that The reinforcing boss (300) has a thickness direction (Y), and a distance between the reinforcing boss (300) and the inner wall of the housing (100) along the thickness direction (Y) is 2 mm to 3 mm.

5. The battery according to claim 4, characterized in that The distance between the reinforcing boss (300) and the inner wall of the housing (100) along the thickness direction (Y) is 2.5 mm.

6. The battery according to claim 4 or 5, characterized in that: A high temperature resistant pad (400) is provided on one side of the reinforcing boss (300) close to the opening (110) along the width direction (Z), the thickness of the high temperature resistant pad (400) is less than or equal to the thickness of the reinforcing boss (300), and the high temperature resistant pad (400) abuts against the inner wall of the shell (100) on one side close to the inner wall of the shell (100) along the thickness direction (Y).

7. The battery according to any one of claims 1 to 5, characterized in that The edge of the cover body (200) is provided with a lap groove (210), and the lap groove (210) contacts the end surface of one end of the opening (110) of the shell (100) and is sealed by laser welding.

8. The battery according to any one of claims 1 to 5, characterized in that The reinforcing boss (300) is integrally formed with the housing (100).

9. A battery pack, characterized in that: A battery comprising the battery according to any one of claims 1 to 8.

10. An electrical device, characterized in that: A battery pack comprising the battery pack of claim 9.

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