Battery case and single battery

Abstract

The utility model discloses a battery case and monomer battery, this battery case includes the lower casing for accommodating electric core and the sealing element for sealing liquid injection hole, and the lower casing and sealing element are all fixedly connected to the upper casing, and the upper casing is rectangular board, and is equipped with liquid injection hole on one corner, wherein, the radius of liquid injection hole is recorded as R, and the distance of the center point of the circle of liquid injection hole to the nearest side edge of the upper casing is recorded as L1, and 0.1mm<=L1-R<=2mm. A battery case and monomer battery, the structure and position of setting liquid injection hole make that the battery case can keep the strength of having, and can effectively guarantee the sealing of liquid injection hole, simplify the manufacturing process simultaneously, effectively guarantee the safety of battery, improve the service life of battery.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, specifically to a battery casing and a single battery cell. Background Technology

[0002] Ultra-thin batteries (typically referring to batteries with a thickness between 0.2mm and 3.5mm) have been widely used in numerous fields, including Mini-phone cards, bank cards / smart cards, information cards, smart wearable devices (such as heated clothing, smart shoes, and smart belts), special equipment, portable sensors, smart tags, miniature speakers, medical devices, and tracking devices, due to their superior thinness. Given that these applications typically face complex, variable, and even harsh physical environments (such as bending, compression, and friction), metal casings with high damage resistance are considered an important development direction for improving battery reliability and durability.

[0003] However, applying metal casings to ultra-thin batteries presents significant challenges to traditional electrolyte injection hole designs. Conventional batteries typically have electrolyte injection holes in 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 create a reliable sealing electrolyte injection hole while meeting mechanical strength requirements. The cover plate, after thinning, lacks sufficient support and cannot withstand the stresses during electrolyte injection, sealing processes, and subsequent use, easily leading to structural failure or poor sealing, seriously affecting battery safety and lifespan. Therefore, the electrolyte injection structure of existing ultra-thin metal-cased batteries has inherent defects, necessitating the development of a novel electrolyte injection hole design suitable for ultra-thin metal-cased batteries that balances structural strength, reliable sealing, and process feasibility to overcome this technological bottleneck. Utility Model Content

[0004] This utility model addresses the problems in the prior art by disclosing a battery casing and its manufacturing method, as well as a single battery cell. By setting the structure of the upper casing, especially the structure and position of the liquid injection hole, this utility model effectively overcomes the problem that insufficient support of the upper casing during the manufacturing process of ultra-thin battery casings can cause overall structural failure or poor sealing, thus affecting battery safety and lifespan.

[0005] This utility model is achieved through the following technical solution:

[0006] This utility model first provides a battery housing, including a lower housing for accommodating battery cells and a sealing element for sealing the liquid injection hole. The lower housing and the sealing element are both fixedly connected to an upper housing. The upper housing 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 housing is denoted as L1. Then, 0.1mm≤L1-R≤2mm.

[0007] As a further option, the distance from the center point of the injection hole to the other, closer edge of the upper shell is denoted as L2, where L1 = L2.

[0008] As a further option, the injection hole includes an upper hole and a lower hole of one-piece structure, the upper hole and the lower hole having different diameters and forming a step at the connection.

[0009] As a further option, the diameter of the lower hole can range from 0.5 to 2 mm.

[0010] As a further option, 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.

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

[0012] As a further option, the upper and lower holes are coaxial and perpendicular to the upper housing.

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

[0014] This utility model also provides a method for manufacturing a battery casing, comprising the following steps:

[0015] S1: Fix the upper housing;

[0016] S2: Machining the lower hole of the injection hole;

[0017] S3: Mill out the step of the injection hole to form the upper hole;

[0018] S4: After the seal is embedded in the upper hole and limited by the step, laser welding is performed to seal it;

[0019] S5: Weld the edge of the upper housing to the flange edge of the lower housing to form a sealed structure for the battery.

[0020] This utility model also provides a single battery cell, including a battery cell and a battery casing, wherein the battery cell is housed within the battery casing.

[0021] The features and beneficial effects of this utility model are as follows:

[0022] The battery casing:

[0023] (1) The structure and position of the injection hole provided by this utility model enable the battery casing to maintain the required strength and effectively ensure the sealing of the injection hole. At the same time, it simplifies the manufacturing process, effectively ensures the safety of the battery, and improves the service life of the battery.

[0024] (2) The present invention sets the injection hole in the area covered by the electrode, so that the electrolyte has enough space to flow inside the shell after injection, and will not hinder the continuous injection of electrolyte.

[0025] (3) The injection hole structure provided by this utility model ensures, on the one hand, that the remaining thickness of the step is sufficient to avoid laser welding through the shell, and on the other hand, that the sealing element has sufficient base material to form a strong weld.

[0026] The manufacturing method of the battery casing:

[0027] (1) The battery casing manufacturing method provided by this utility model can balance the smoothness of liquid injection and the welding space of the sealing component, effectively extend the welding path to disperse welding heat, improve welding quality, avoid burning through the ultra-thin casing, and the 45° tilt angle can also utilize the capillary action between the electrolyte and the upper casing to accelerate electrolyte filling and promote the upward escape of bubbles along the hole wall.

[0028] The battery:

[0029] (1) The battery casing of this utility model has high strength, which can effectively protect the cell structure inside the casing, effectively ensure the safety of the battery and improve the service life of the battery. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is an exploded view of the battery casing described in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the battery casing according to an embodiment of the present utility model;

[0033] Figure 3 This is a front view of the battery casing according to an embodiment of the present invention;

[0034] Figure 4 This is a side view of the battery casing described in an embodiment of the present invention;

[0035] Figure 5 This is a front view of the sealing element described in an embodiment of the present utility model;

[0036] Figure 6 This is a schematic diagram of the sealing element described in an embodiment of the present utility model;

[0037] Figure 7This is a schematic diagram showing the positional relationship of the injection holes according to an embodiment of the present invention;

[0038] Figure 8 This is a side view of the upper housing as described in an embodiment of the present utility model;

[0039] Figure 9 This is a cross-sectional view of the injection hole in Embodiment 1 of this utility model;

[0040] Figure 10 This is a cross-sectional view of the injection hole in Embodiment 2 of this utility model.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1-Upper housing; 11-Injection hole; 111-Upper hole; 112-Lower hole; 2-Lower housing; 21-Flange edge; 22-Pole post assembly; 3-Seal. Detailed Implementation

[0043] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be provided below, along with embodiments of this utility model, but this does not limit the scope of this utility model.

[0044] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] A battery casing, such asFigures 1 to 10 As shown, the device includes an upper housing 1 and a lower housing 2. The lower housing 2 has a cavity inside for accommodating the battery cell. The opening edge of the lower housing 2 extends outward to form a flange edge 21. The side wall of the lower housing 2 is also provided with a terminal assembly 22 for connecting the internal tab of the battery cell to the external circuit. The upper housing 1 is a rectangular plate with a liquid injection hole 11 at one corner. The radius of the liquid injection hole 11 is denoted as R, and the distance from the center point of the liquid injection hole 11 to the nearest edge of the upper housing 1 is denoted as L1. Then, 0.1mm≤L1-R≤2mm.

[0047] The battery casing structure of this application can effectively ensure the strength and support of the battery casing, effectively ensure the stability of the battery, and extend the battery's service life.

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

[0049] The adverse effects of L1-R < 0.1mm: (1) The thinnest wall thickness that can be achieved under the current shell processing capability is 0.05mm, and the positioning accuracy error leaves a margin of 0.05mm. If L1-R < 0.1mm, there is a risk of damaging the shell wall when processing the injection hole, resulting in perforation and leakage of the shell wall; (2) The high temperature heat generated when welding the upper and lower shells will be significantly conducted to the injection hole area, which may cause micro-deformation, oxidation or change of material properties of the metal around the injection hole, which will seriously affect the sealing accuracy and reliability of the subsequent injection hole (such as poor welding of the sealing parts or uneven sealing surface). The adverse effects of L1-R > 2mm: (1) The current electrode covering area is generally not greater than 2mm. If L1-R > 2mm, the projection of the injection hole in the thickness direction coincides with the projection of the internal stacked core in the thickness direction, which will lead to problems such as the electrolyte not being able to be injected and easy to spray liquid; (2) The electrolyte needs to flow through the gap between the long battery cell and the inner wall of the shell before it can gradually penetrate into the pore structure inside the battery cell. This excessively long flow path will significantly reduce the rate and uniformity of electrolyte wetting of the electrode, affecting the battery wetting efficiency, and may even lead to incomplete wetting and affect battery performance; (3) The setting of L1 near the corner makes the injection hole closer to the two sides of the lower shell, and the two sides of the lower shell can provide sufficient support for the stress in the injection, sealing and other processes and subsequent use.

[0050] In one or more embodiments, such as Figure 7 As shown, since the injection hole 11 is located at one corner of the upper shell 1, the distance between the center point of the injection hole 11 and the other closer edge of the upper shell 1 is denoted as L2. Preferably, L1=L2. At this time, the injection hole 11 is equidistant from the two closest edges, resulting in uniform force distribution, which is beneficial for maintaining stability.

[0051] Preferably, the injection hole 11 is located in the area covered by the electrode, so that after injection, the electrolyte has enough space to flow inside the shell and will not hinder the continuous injection of electrolyte.

[0052] Preferably, the lower housing 2 is manufactured using a single-sided stamping process to form a cavity for accommodating the battery cell. The upper housing 1 is a flat cover plate. Both the upper housing 1 and the lower housing 2 are made of metal.

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

[0054] The upper hole 111 has a diameter of D and is used to accommodate the sealing element 3 and weld it to the sealing element 3 to achieve the sealing of the injection hole; the lower hole 112 has a diameter of d and is used to cooperate with the injection needle to inject electrolyte. Here, d = 0.5~2mm. If d is too small, the electrolyte will be difficult to inject, the injection efficiency will be low, and the internal air bubbles will be difficult to remove. If d is too large, it will weaken the shell strength, increase the welding path, and result in low production efficiency.

[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 inserted and laser welded to the upper housing 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 housing 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, this ensures that the remaining thickness of the step is sufficient to avoid laser welding through the housing. On the other hand, it ensures that the sealing element 3 has sufficient substrate to form a strong weld. Example

[0057] The axis of injection hole 11 is perpendicular to the upper shell 1.

[0058] Specifically, the injection hole 11 includes an upper hole 111 and a lower hole 112 with an integral 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. Example

[0059] 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 can lead to an excessively large heat-affected zone during welding. Furthermore, the injection efficiency of a vertical injection hole is slow, and air bubbles are difficult to expel. Therefore, an implementation example with an inclined injection hole design is provided.

[0060] The structural diagram of the upper shell 1 and the cross-sectional view at the injection hole are shown in the following figure.

[0061] The injection hole 11 includes an integral upper hole 111 and a lower hole 112. The two holes have different diameters and form a step at the connection. The axis of the upper hole 111 is perpendicular to the upper shell 1, and the axis of the lower hole 112 makes an angle A with the upper shell 1, preferably 45°±5°. Within this range, the smoothness of the injection and the welding space of the sealing element can be balanced, effectively extending the welding path to disperse welding heat, improving welding quality, and avoiding burn-through of the ultra-thin shell. The 45° tilt angle can also utilize the capillary action between the electrolyte and the upper shell 1 to accelerate electrolyte filling and promote the upward escape of air bubbles along the hole wall. Unlike Embodiment 1, in this embodiment, the injection hole 11 is an inclined injection hole, used to inject electrolyte into the sealed space formed by the lower shell cavity and the upper shell. After injection, the injection hole is reliably sealed by the sealing element.

[0062] A method for manufacturing a battery casing,

[0063] S1: First, fix the upper shell 1;

[0064] S2: Machining the lower hole 112 of the injection hole;

[0065] S3: Mill out a step to form an upper hole 111 for placing the seal 3.

[0066] S4: The sealing element 3 is embedded in the upper hole 111 and then laser-welded to seal after being limited by the step.

[0067] It should be noted that steps 3 and 4 above cannot be reversed. The machining process of drilling first and then milling the steps can ensure angular accuracy and cleanliness of the injection hole. On the contrary, the machining process of milling the steps first and then drilling may result in the drilling being skewed due to the insufficient thickness of the cover plate wall, leading to material scrap.

[0068] The diameter of the seal is the same as the diameter D of the upper step, and the material is the same as the upper cover plate, which facilitates welding.

[0069] S5: The edge of the upper housing 1 and the flange edge 21 of the lower housing 2 are connected together by welding (preferably laser welding) to form a sealed encapsulation structure for the battery.

[0070] It should be noted that steps S3 and S4 above cannot be reversed. The machining process of drilling first and then milling the steps can ensure angular accuracy and cleanliness of the injection hole. On the contrary, the machining process of milling the steps first and then drilling may result in the drilling being skewed due to the insufficient thickness of the cover plate wall, leading to material scrap.

[0071] The diameter of the seal 3 is the same as the diameter D of the upper hole 111, and the material is the same as that of the upper shell 1, which facilitates welding. Example

[0072] X1: First, fix the upper shell 1;

[0073] X2: Drill the lower hole 112 of the injection hole along a direction that is 90° to the normal of the upper shell 1;

[0074] X3: A step is milled to form an upper hole 111, which is used to place the seal 3.

[0075] X4: The sealing element 3 is embedded in the upper hole 111 and then laser-welded to seal after being limited by the step.

[0076] It should be noted that steps X3 and X4 above cannot be reversed. The machining process of drilling first and then milling the steps can ensure angular accuracy and cleanliness of the injection hole. On the contrary, the machining process of milling the steps first and then drilling may result in the drilling being skewed due to the insufficient thickness of the cover plate wall, leading to material scrap.

[0077] The diameter of the seal 3 is the same as the diameter D of the upper hole 111, and the material is the same as that of the upper shell 1, which facilitates welding.

[0078] X5: The edge of the upper housing 1 and the flange edge 21 of the lower housing 2 are connected together by welding to form a sealed encapsulation structure for the battery. Example

[0079] Y1: First, fix the upper shell 1 by using a clamp with a 45° bevel.

[0080] Y2: Drill the lower hole 112 of the injection hole 11 along a direction at a 40°~50° angle to the normal of the upper shell 1;

[0081] Y3: Mill a step to form an upper hole 111 for placing the seal 3.

[0082] Y4: The sealing element 3 is embedded in the upper hole 111 and limited by the step, and then sealed by laser welding.

[0083] It should be noted that steps Y3 and Y4 above cannot be reversed. The machining process of drilling the lower hole 112 first and then milling the step and the upper hole 111 can ensure angular accuracy and cleanliness of the injection hole. On the contrary, the machining process of machining the upper hole 111 first, milling the step, and then drilling the lower hole 112 may result in the upper shell 1 having too small a wall thickness, causing the drilling to be skewed and resulting in material scrap.

[0084] Y5: The edge of the upper housing 1 and the flange edge 21 of the lower housing 2 are connected together by welding to form a sealed encapsulation structure for the battery.

[0085] A single-cell battery includes a cell and a battery casing, wherein the cell is disposed within a recessed cavity. The battery casing has high structural strength, effectively ensuring battery safety and improving battery lifespan.

[0086] In summary, the battery casing structure of this application, with its specific structure and location of the liquid injection hole, enables the battery casing to maintain the required strength and effectively ensures the sealing of the liquid injection hole. It also simplifies the manufacturing process, effectively guarantees battery safety, and extends battery lifespan.

[0087] It should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A battery casing, comprising a lower casing for accommodating a battery cell and a sealing element for sealing a liquid injection port, characterized in that: The lower housing and the seal are both fixedly connected to the upper housing. The upper housing is a rectangular plate with an injection hole at one corner. The radius of the injection hole is denoted as R, and the distance from the center of the injection hole to the nearest edge of the upper housing is denoted as L1. Then, 0.1mm≤L1-R≤2mm.

2. The battery casing according to claim 1, characterized in that: The distance from the center of the injection hole to the edge of the upper shell that is closer to the other side is denoted as L2, where L1 = L2.

3. A battery casing according to claim 1, characterized in that: The injection port consists of an integral upper and lower hole with different diameters and a step 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. A 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 following relationship: 1.01 ≤ D / d ≤ 1.

5.

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

7.

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

8. A battery casing according to claim 3, characterized in that: 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 is 45°±5°.

9. A single-cell battery, characterized in that, It includes a battery cell and a battery casing as described in any one of claims 1-8, wherein the battery cell is housed within the battery casing.

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