Battery shell, manufacturing method thereof and single battery

Abstract

The invention discloses a battery shell and a manufacturing method thereof as well as a single battery, the battery shell comprises a lower shell for accommodating a battery cell and a sealing element for sealing a liquid injection hole, the lower shell and the sealing element are fixedly connected to the upper shell, the upper shell is a rectangular plate, one corner of the upper shell is provided with the liquid injection hole, the radius of the liquid injection hole is marked as R, and the radius of the liquid injection hole is marked as S; the distance between the circle center point of the liquid injection hole and the edge of the nearest side of the upper shell is recorded as L1, and L1-R is larger than or equal to 0.1 mm and smaller than or equal to 2mm. According to the battery shell, the manufacturing method of the battery shell and the single battery, due strength of the battery shell can be kept through the structure and the position of the liquid injection hole, the sealing performance of the liquid injection hole can be effectively guaranteed, meanwhile, the manufacturing process is simplified, the safety of the battery is effectively guaranteed, and the service life of the battery is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium batteries, in particular to a battery shell, a manufacturing method thereof and a single battery. BACKGROUND

[0002] Ultra-thin batteries (usually referring to batteries with a thickness of 0.2mm to 3.5mm) have been widely used in many fields such as Mini-phone cards, bank cards / smart cards, information cards, smart wearable devices (such as heated clothes, smart shoes, smart belts), special equipment, portable sensors, smart tags, micro-speakers, medical devices and tracking devices, etc. due to their excellent thinness. Given that the above-mentioned application scenarios usually face complex and even harsh physical environments (such as bending, extrusion, friction, etc.), metal shells with high damage resistance are considered as an important development direction to improve the reliability and durability of batteries.

[0003] However, when applying a metal shell to an ultra-thin battery, the conventional liquid injection hole structure design faces significant challenges. Conventional batteries usually have a liquid injection hole on the cover plate. However, for ultra-thin batteries, their extremely small thickness severely limits the structural strength of the cover plate, making it impossible to directly open a reliably sealed liquid injection hole on it while meeting the mechanical strength requirements. After thinning, the cover plate lacks support and is difficult to withstand the stress during the liquid injection, sealing and subsequent use processes, easily causing structural failure or poor sealing, which seriously affects the safety and life of the battery. Therefore, the liquid injection structure of the existing ultra-thin metal shell battery has inherent defects, and a new liquid injection hole design scheme that is suitable for ultra-thin metal shell batteries and can balance structural strength, reliable sealing and process feasibility is urgently needed to break through this technical bottleneck. SUMMARY

[0004] The present application discloses a battery shell, a manufacturing method thereof and a single battery, which effectively overcomes the problem of structural failure or poor sealing of the overall structure caused by insufficient support of the upper shell during the manufacturing process of the ultra-thin battery shell, affecting the safety and life of the battery, by setting the structure of the upper shell, especially the structure and position of the liquid injection hole.

[0005] The present application is achieved by the following technical solutions:

[0006] The present application first provides a battery shell, which includes a lower shell for accommodating an electric core and a sealing element for sealing a liquid injection hole, the lower shell and the sealing element are both fixedly connected to an upper shell, and the upper shell is a rectangular plate with a liquid injection hole at one corner. The radius of the liquid injection hole is denoted as R, and the distance from the center point of the liquid injection hole to the nearest edge of the upper shell is denoted as L1, then 0.1mm≤L1-R≤2mm.

[0007] As a further scheme, the distance between the center point of the liquid injection hole and the edge of the other side of the upper shell is recorded as L2, wherein L1=L2.

[0008] As a further scheme, the liquid injection hole comprises an upper hole and a lower hole in an integral structure, the diameters of the upper hole and the lower hole are different and a step is formed at the connection.

[0009] As a further scheme, the diameter of the lower hole ranges from 0.5 to 2 mm.

[0010] As a further scheme, the diameter of the upper hole is D and the diameter of the lower hole is d, which should satisfy the relationship: 1.01≤D / d≤1.5.

[0011] As a further scheme, the wall thickness of the upper shell is recorded as Y2, the hole depth of the lower hole is recorded as Y1, Y1 and Y2 should satisfy the relationship: 0.3≤Y1 / Y2≤0.7.

[0012] As a further scheme, the upper hole and the lower hole are coaxial and perpendicular to the upper shell.

[0013] As a further scheme, the axis of the upper hole is perpendicular to the upper shell, and the angle between the axis of the lower hole and the upper shell ranges from 45°±5°.

[0014] The application also provides a manufacturing method of the battery shell, comprising the following steps:

[0015] S1: fixing the upper shell;

[0016] S2: processing the lower hole of the liquid injection hole;

[0017] S3: milling the step of the liquid injection hole to form the upper hole;

[0018] S4: embedding the sealing element into the upper hole and limiting by the step, and then performing laser welding sealing;

[0019] S5: welding the edge of the upper shell and the flange edge of the lower shell into an integral structure to form the sealing structure of the battery.

[0020] The application also provides a single battery, comprising a battery cell and the battery shell according to any one of claims 1-8, wherein the battery cell is accommodated in the battery shell.

[0021] The application has the following characteristics and advantages:

[0022] The battery shell has the following characteristics:

[0023] (1) The structure and position of the liquid injection hole provided by the application can maintain the strength of the battery shell, effectively ensure the sealing of the liquid injection hole, simplify the manufacturing process, effectively ensure the safety of the battery, and prolong the service life of the battery.

[0024] (2)The present application sets the liquid injection hole in the area of the electrode coating, so that after the electrolyte is injected, the electrolyte has enough space to flow inside the shell and will not block the continuous injection of electrolyte.

[0025] (3)The liquid injection hole structure provided by the present application can ensure that the remaining thickness of the step is sufficient to avoid laser welding through the shell, and ensure that the sealing element has enough substrate to form a firm weld.

[0026] The manufacturing method of the battery shell:

[0027] (1)The manufacturing method of the battery shell provided by the present application can balance the flow of the electrolyte and the welding space of the sealing element, effectively extend the welding path to disperse the welding heat, improve the welding quality, avoid burning through the ultra-thin shell, and the 45° inclination angle can also utilize the capillary action of the electrolyte and the upper shell to accelerate the electrolyte filling and promote the bubbles to escape along the hole wall.

[0028] The battery:

[0029] (1)The battery shell of the present application has high strength, can effectively protect the cell structure inside the shell, effectively ensures the safety of the battery, and prolongs the service life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0031] Figure 1 The exploded view of the battery shell described in the embodiments of the present application;

[0032] Figure 2 The schematic diagram of the battery shell described in the embodiments of the present application;

[0033] Figure 3 The front view of the battery shell described in the embodiments of the present application;

[0034] Figure 4 The side view of the battery shell described in the embodiments of the present application;

[0035] Figure 5 The front view of the sealing element described in the embodiments of the present application;

[0036] Figure 6 The schematic diagram of the sealing element described in the embodiments of the present application;

[0037] Figure 7 The position relationship diagram of the liquid injection hole described in the embodiments of the present application;

[0038] Figure 8 A side view of the upper shell according to an embodiment of the present application;

[0039] Figure 9 A sectional view of the liquid injection hole according to Embodiment 1 of the present application;

[0040] Figure 10 A sectional view of the liquid injection hole according to Embodiment 2 of the present application.

[0041] BRIEF DESCRIPTION OF DRAWINGS

[0042] 1 - upper shell; 11 - liquid injection hole; 111 - upper hole; 112 - lower hole; 2 - lower shell; 21 - flange; 22 - pole assembly; 3 - sealing member. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present application, a more comprehensive description of the present application will be given below, and embodiments of the present application are given, but the scope of the present application is not limited thereto.

[0044] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0045] In the description of the present 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, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0046] A battery shell, such as Figures 1 to 10As shown, the battery shell structure includes an upper shell 1 and a lower shell 2, the lower shell 2 is internally provided with a recess for accommodating the battery core, the opening edge of the lower shell 2 extends outward to form a flange edge 21, and the side wall of the lower shell 2 is further provided with a pole assembly 22 for connecting the internal tab of the battery core and the external circuit. The upper shell 1 is a rectangular plate, one corner of which is provided with a liquid injection hole 11, wherein the radius of the liquid injection hole 11 is denoted as R, the distance from the center point of the liquid injection hole 11 to the nearest side edge of the upper shell 1 is denoted as L1, and 0.1mm≤L1-R≤2mm.

[0047] The battery shell structure of the present application can effectively ensure the strength and support of the battery shell, effectively ensure the stability of the battery, and prolong the service life of the battery.

[0048] The liquid injection hole 11 is used to inject electrolyte into the sealed space formed by the lower shell recess and the upper shell. After the injection is completed, the liquid injection hole 11 is reliably sealed by the sealing element 3.

[0049] The adverse effects of L1-R<0.1mm are: (1) The thinnest wall thickness that can be achieved under the existing shell processing capacity is 0.05mm, and the positioning accuracy error has a margin of 0.05mm. If L1-R<0.1mm, there is a risk of damaging the shell wall when machining the liquid injection hole, resulting in a perforated shell wall and electrolyte leakage. (2) The high temperature generated during the welding of the upper and lower shells will be significantly conducted to the liquid injection hole area, which may cause micro-deformation, oxidation or change of material properties of the metal around the liquid injection hole, thereby seriously affecting the sealing precision and reliability of the subsequent liquid injection hole (such as poor sealing element welding or uneven sealing surface). The adverse effects of L1-R>2mm are: (1) The current electrode coating area is generally not greater than 2mm. If L1-R>2mm, the projection of the liquid injection hole in the thickness direction coincides with the projection of the internal stacked core in the thickness direction, which may cause problems such as electrolyte injection failure and easy liquid spraying. (2) The electrolyte needs to flow through the gap between the longer electrode and the inner wall of the shell first, and then gradually penetrate into the pore structure inside the electrode. This excessively long flow path significantly reduces the rate and uniformity of electrolyte wetting the electrode, affecting the battery wetting efficiency, and may even cause incomplete wetting and affect the battery performance. (3) The setting of L1 close to the corner makes the liquid injection hole closer to the two side edges of the lower shell, which can provide sufficient support for the liquid injection, sealing and other process and subsequent use.

[0050] In one or more embodiments, as shown in Figure 7 Since the liquid injection hole 11 is provided on one corner of the upper shell 1, the distance from the center point of the liquid injection hole 11 to the other side edge of the upper shell 1 is denoted as L2, and preferably L1=L2. At this time, the liquid injection hole 11 is the same distance from the two nearest edges, and the stress is uniform, which is beneficial to maintain stability.

[0051] Preferably, the injection hole 11 is set in the area covered by the electrode, so that after the injection, there is enough space for the electrolyte to flow inside the shell and the continuous injection of the electrolyte will not be blocked.

[0052] Preferably, the lower shell 2 is made by a single-sided stamping process to form a cavity for accommodating the battery cell. The upper shell 1 is a flat cover. The material of the upper shell 1 and the lower shell 2 are both metal.

[0053] In one or more embodiments, the liquid injection hole 11 includes an upper hole 111 and a lower hole 112 of an integral structure. The two holes have different diameters and a step is formed at the connection.

[0054] The diameter of the upper hole 111 is D, which is used to accommodate the seal 3 and is welded to the seal 3 to achieve sealing of the injection hole; the diameter of the lower hole 112 is d, which is used to cooperate with the injection needle to inject electrolyte, where d = 0.5~2mm. If d is too small, the electrolyte is difficult to inject, the injection efficiency is low, and internal bubbles are difficult to remove. If d is too large, the shell strength will be weakened, the welding path will be increased, and the production efficiency will be low.

[0055] In one or more embodiments, the diameter D of the upper hole 111 should be slightly larger than the diameter d of the lower hole 112 to provide support and positioning, so that the seal 3 can be placed and laser welded with the upper shell 1; preferably, the diameter D of the upper hole 111 and the diameter d of the lower hole 112 should satisfy the relationship: 1.01≤D / d≤1.5.

[0056] In one or more embodiments, the wall thickness of the upper shell 1 is denoted as Y2, and the hole depth of the lower hole 112 is denoted as Y1. Y1 and Y2 should satisfy the relationship: 0.3≤Y1 / Y2≤0.7. On the one hand, it ensures that the remaining thickness of the step is sufficient to avoid laser welding through the shell. On the other hand, it ensures that the seal 3 has sufficient base material to form a solid weld.

[0057] Example 1

[0058] The axis of the liquid injection hole 11 is perpendicular to the upper shell 1 .

[0059] Specifically, the liquid injection hole 11 includes an upper hole 111 and a lower hole 112 of an integrated structure. The two holes have different diameters and form a step at the connection. The upper hole 111 and the lower hole 112 are coaxial and perpendicular to the upper shell 1.

[0060] Example 2

[0061] When batteries are very thin, especially those less than 2mm thick, the casing wall thickness is usually designed to be even thinner. A vertical design on an ultra-thin casing results in an excessively large heat-affected zone (HAZ) during welding. Furthermore, the vertical injection hole has slow filling efficiency and difficulty in evacuating bubbles. Therefore, an alternative implementation example of an inclined injection hole design is provided.

[0062] The upper shell 1 structure diagram and the liquid injection hole section view are shown in the following figure,

[0063] The liquid injection hole 11 includes an integrated structure of the upper hole 111 and the lower hole 112, the diameters of the two holes are different and a step is formed at the connection, wherein the axis of the upper hole 111 is perpendicular to the upper shell 1, and the angle A between the axis of the lower hole 112 and the upper shell 1 is preferably 45°±5°. Within this range, the flow of the liquid injection and the welding space of the sealing element can be balanced, the welding path is effectively dispersed to disperse the welding heat, the welding quality is improved, the ultra-thin shell is prevented from being burned through, and the 45° inclination angle can also utilize the capillary action of the electrolyte and the upper shell 1 to accelerate the filling of the electrolyte and promote the escape of bubbles along the hole wall upward. Unlike the first embodiment, the liquid injection hole 11 in this embodiment is an inclined liquid injection hole, which is used to inject electrolyte into the sealed space formed by the lower shell cavity and the upper shell. After the liquid injection is completed, the liquid injection hole is reliably sealed by the sealing element.

[0064] A battery shell manufacturing method,

[0065] S1: First, fix the upper shell 1;

[0066] S2: Process the lower hole 112 of the liquid injection hole;

[0067] S3: Mill out the step to form the upper hole 111 for placing the sealing element 3.

[0068] S4: The sealing element 3 is embedded in the upper hole 111 and limited by the step, and then laser welding is performed for sealing.

[0069] Note that steps 3 and 4 above cannot be reversed, and the processing procedure of drilling first and then milling the step can ensure the angle accuracy and ensure the cleanliness of the liquid injection hole; on the contrary, the processing procedure of milling the step first and then drilling exists that the cover plate wall thickness is too small, which leads to drilling deviation and material scrap.

[0070] The diameter of the sealing element is consistent with the diameter D of the upper step, and the material is consistent with the upper cover plate, which is convenient for welding.

[0071] S5: The edge of the upper shell 1 and the flange edge 21 of the lower shell 2 are connected into one body by welding (preferably laser welding), and together form a sealed packaging structure of the battery.

[0072] Note that steps S3 and S4 above cannot be reversed, and the processing procedure of drilling first and then milling the step can ensure the angle accuracy and ensure the cleanliness of the liquid injection hole; on the contrary, the processing procedure of milling the step first and then drilling exists that the cover plate wall thickness is too small, which leads to drilling deviation and material scrap.

[0073] The diameter of the sealing element 3 is consistent with the diameter D of the upper hole 111, and the material is consistent with the upper shell 1, which is convenient for welding.

[0074] Embodiment 1

[0075] X1: First, fix the upper shell 1;

[0076] X2: Drill the lower hole 112 of the liquid injection hole in the direction of 90° to the normal line of the upper shell 1;

[0077] X3: Mill the upper hole 111 to form a step for placing the sealing element 3.

[0078] X4: The sealing element 3 is embedded in the upper hole 111 and is limited by the step, and then laser welding is performed for sealing.

[0079] It should be noted that the above steps X3 and X4 cannot be reversed. The processing procedure of drilling first and then milling the step can ensure the angle accuracy and ensure the cleanliness of the liquid injection hole; otherwise, the processing procedure of milling the step first and then drilling exists that the cover plate wall thickness is too small, which leads to drilling deviation and material scrap.

[0080] The diameter of the sealing element 3 is consistent with the diameter D of the upper hole 111, and the material is consistent with the upper shell 1, which is convenient for welding.

[0081] X5: The edge of the upper shell 1 and the flange edge 21 of the lower shell 2 are connected into one body by welding, and together form a sealed packaging structure of the battery.

[0082] Embodiment 2

[0083] Y1: First, fix the upper shell 1 by a clamp with a 45° inclined surface;

[0084] Y2: Drill the lower hole 112 of the liquid injection hole 11 in the direction of 40°-50° to the normal line of the upper shell 1;

[0085] Y3: Mill the upper hole 111 to form a step for placing the sealing element 3.

[0086] Y4: The sealing element 3 is embedded in the upper hole 111 and is limited by the step, and then laser welding is performed for sealing.

[0087] It should be noted that the above steps Y3 and Y4 cannot be reversed. The processing procedure of drilling the lower hole 112 first and then milling the step and the upper hole 111 can ensure the angle accuracy and ensure the cleanliness of the liquid injection hole; otherwise, the processing procedure of milling the step of the upper hole 111 first and then drilling the lower hole 112 exists that the wall thickness of the upper shell 1 is too small, which leads to drilling deviation and material scrap.

[0088] Y5: The edge of the upper shell 1 and the flange edge 21 of the lower shell 2 are connected into one body by welding, and together form a sealed packaging structure of the battery.

[0089] The application relates to a single battery, which comprises an electric core and a battery shell, wherein the electric core is arranged in the concave cavity.

[0090] In conclusion, the battery shell structure, the structure and position of the liquid injection hole of the application can keep the strength of the battery shell, effectively guarantee the sealing of the liquid injection hole, simplify the manufacturing process, effectively guarantee the safety of the battery and prolong the service life of the battery.

[0091] It should be noted that the above description is only the preferred embodiment of the application, and is not used to limit the application. Any modification, equivalent replacement, improvement and the like within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A battery housing, characterized in that: It includes an upper shell and a lower shell. The lower shell is made by a single-sided stamping process. A concave cavity is provided inside for accommodating the battery cell. The edge of the opening extends outward to form a flange edge. The side wall is also provided with a pole assembly for connecting the internal pole ear of the battery cell with the external circuit. The upper shell is a rectangular plate, and a liquid injection hole is provided on one corner. The radius of the liquid injection hole is recorded as R, and the distance from the center point of the liquid injection hole to the nearest edge of the upper shell is recorded as L1. Then 0.1mm≤L1-R≤2mm; the distance from the center point of the liquid injection hole to the other closer edge of the upper shell is recorded as L2, wherein L1=L2.

2. A battery casing according to claim 1, characterized in that: The injection hole is arranged in the area covered by the electrode.

3. The battery housing according to claim 1, wherein: The injection hole includes an upper hole and a lower hole of an integral structure. The diameters of the upper hole and the lower hole are different and a step is formed at the connection.

4. A battery casing according to claim 3, characterized in that: The diameter of the lower hole ranges from 0.5 to 2 mm.

5. The battery casing according to claim 3, characterized in that: The diameter of the upper hole D and the diameter of the lower hole d should satisfy the relationship: 1.01≤D / d≤1.

5.

6. The battery casing according to claim 3, characterized in that: The wall thickness of the upper shell is recorded as Y2, and the hole depth of the lower hole is recorded as Y1. Y1 and Y2 should satisfy the relationship: 0.3≤Y1 / Y2≤0.

7.

7. The battery casing according to claim 3, characterized in that: The upper hole and the lower hole are coaxial and perpendicular to the upper shell.

8. The battery casing according to claim 3, characterized in that: The axis of the upper hole is perpendicular to the upper shell, and the angle range between the axis of the lower hole and the upper shell is: 45°±5°.

9. A method for manufacturing a battery casing according to any one of claims 1 to 8, characterized in that: The steps include: S1: fix the upper shell; S2: Processing the lower hole of the injection hole; S3: milling out the steps of the injection hole to form the upper hole; S4: Insert the seal into the upper hole and then perform laser welding and sealing after passing through the step limit; S5: Welding the edge of the upper shell and the flange edge of the lower shell into one piece to form a sealed structure of the battery.

10. A single cell battery, characterized in that: The invention comprises a battery cell and a battery casing according to any one of claims 1 to 8, wherein the battery cell is accommodated in the battery casing.

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