A battery casing and a lithium battery

Abstract

This utility model discloses a battery casing and a lithium battery, belonging to the field of lithium battery technology. The casing includes an explosion-proof hole that penetrates one side plate of the casing. The side plate includes a first plane and a second plane arranged opposite to each other, with the second plane facing the battery cell. A reinforcing bracket is provided along the outer periphery of the explosion-proof hole on the second plane, protruding away from the second plane. The outline of the reinforcing bracket's orthographic projection on the second plane matches the outer periphery of the explosion-proof hole. The reinforcing bracket of this utility model improves the strength of the casing, preventing deformation of the casing under high internal pressure and ensuring stable opening of the explosion-proof valve. Moreover, the reinforcing bracket also supports the battery cell. When the battery cell expands or shifts, the reinforcing bracket blocks the cell, preventing blockage of the explosion-proof hole and ensuring smooth venting.

Description

Technical Field

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

[0002] Square lithium batteries have become the mainstream choice for electric vehicle power batteries due to their advantages such as high energy density, high packaging reliability, and high system energy efficiency. The casing of a square lithium battery typically includes a top cover, casing, positive electrode plate, negative electrode plate, a diaphragm consisting of stacked or wound layers, insulation components, and safety components.

[0003] When a single battery cell is overcharged or experiences thermal runaway, it generates a large amount of heat that cannot be quickly dissipated, potentially leading to battery fire or even explosion. The explosion-proof valve is a crucial pressure relief component in the battery top cover assembly. Explosion-proof valves typically have a weak point; when the internal pressure of the battery exceeds a threshold, the valve ruptures at this weak point, releasing gas and preventing an explosion. To prevent the weak point of the explosion-proof valve from melting due to welding, leading to valve failure, existing technology, such as Chinese patent document CN116557596A, discloses an explosion-proof valve with reinforcing ribs spaced around the weak point. Connecting ribs connect the reinforcing ribs to the edge of the weak point, increasing the structural strength of the explosion-proof valve.

[0004] Typically, explosion-proof valves are installed in explosion-proof vents, which are located on the top cover or battery casing. When the pressure inside the battery casing increases, the pressure concentrates at the explosion-proof vent and is released by opening the explosion-proof valve. However, excessive pressure may cause deformation of the casing near the explosion-proof vent, and this deformation can affect the opening of the explosion-proof valve. Utility Model Content

[0005] The purpose of this utility model is to provide a battery casing and a lithium battery, which solves the problem in the prior art that the large pressure generated inside the battery casing may cause the casing near the explosion-proof hole to deform and affect the opening of the explosion-proof valve.

[0006] To achieve the above objectives, this utility model provides a battery casing including an explosion-proof hole, which is disposed through a side plate of the casing; the side plate includes a first plane and a second plane disposed opposite to each other, the second plane being disposed towards the battery cell; a reinforcing bracket is disposed along the outer periphery of the second plane, the reinforcing bracket protruding in a direction away from the second plane, and the outline of the orthographic projection of the reinforcing bracket on the second plane is consistent with the outer periphery outline of the explosion-proof hole.

[0007] Furthermore, the reinforcing bracket has at least one air guide groove, and the air guide groove and the explosion-proof hole do not interfere with each other.

[0008] The gas guide channel and the explosion-proof hole are located independently and do not intersect. Gas can be released by filling the explosion-proof hole or discharged to both sides through the gas guide channel, which further improves the gas release capacity.

[0009] Furthermore, there are two air guide channels, which are symmetrically arranged about the center of the reinforcing bracket.

[0010] Through the above technical solutions, the high-pressure gas inside the casing can be released to both sides while being discharged through the explosion-proof hole, thus appropriately relieving the pressure on the explosion-proof hole.

[0011] Furthermore, the depth of the gas guide groove is less than or equal to the height of the reinforcing bracket. The gas guide groove can form a completely broken or partially broken section on the reinforcing bracket, thereby improving gas release efficiency while ensuring the structural strength of the reinforcing bracket.

[0012] Furthermore, the outline of the reinforcing bracket in the orthographic projection of the second plane is a rounded rectangle, which includes a straight side and an arc side. Both the straight side and the arc side of the reinforcing bracket are provided with air guide grooves, and the width of the air guide groove on the straight side is smaller than the width of the air guide groove on the arc side.

[0013] The straight side is longer and the air guide groove is narrower. While improving the air guiding function of the reinforcing bracket, it can ensure that the reinforcing bracket has a longer length to support the battery cell and improve the structural strength around the explosion-proof hole of the shell.

[0014] Furthermore, the protrusion height H of the reinforcing bracket is 0.1mm to 3mm, which can reduce the impact on the internal space of the housing and not affect the battery cell assembly; the width D of the outline of the reinforcing bracket projected onto the second plane is greater than 0.5mm, which can ensure a certain mechanical strength. The height and width of the reinforcing bracket can ensure the strength of the housing around the explosion-proof hole while minimizing the weight of the reinforcing bracket.

[0015] Furthermore, the first plane is provided with a welding part, which surrounds the outer periphery of the explosion-proof hole, and the welding part is a sinking structure.

[0016] The supporting function of the submerged structure, combined with the increased welding area, enhances the overall load-bearing capacity, optimizes stress distribution and sealing, and extends the service life of the explosion-proof valve and battery housing. Furthermore, under extreme operating conditions, the submerged structure prevents the explosion-proof valve from falling off or shifting, ensuring a controllable pressure relief process.

[0017] This utility model also provides a lithium battery, including the battery casing described above.

[0018] Compared with existing known technologies, the technical solution provided by this utility model has the following beneficial effects:

[0019] This utility model discloses a battery casing with explosion-proof holes on the side plates, providing a more open gas venting channel that is less prone to blockage by cell displacement or other components. The shape and distribution of the reinforcing brackets effectively disperse stress, preventing stress concentration around the explosion-proof holes and thus reducing the risk of cracking or deformation due to excessive stress. The reinforcing brackets increase the strength of the casing, preventing deformation under high internal pressure and ensuring stable opening of the explosion-proof valve. Furthermore, the reinforcing brackets also support the battery cells; when the cells expand or shift, the brackets block them, preventing blockage of the explosion-proof holes and ensuring smooth venting.

[0020] It is obvious that the elements or features described in the above individual embodiments can be used alone or in combination in other embodiments. Attached Figure Description

[0021] The dimensions and scales in the accompanying drawings do not represent the actual dimensions and scales of the product. The drawings are for illustrative purposes only, and some non-essential elements or features have been omitted for clarity.

[0022] Figure 1 This is a schematic diagram of the external structure of the battery casing in an embodiment of this utility model;

[0023] Figure 2 yes Figure 1 A schematic diagram of the battery casing projected from the Y direction;

[0024] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure at point AA;

[0025] Figure 4 This is a schematic diagram of another structure of the reinforcing bracket in an embodiment of this utility model;

[0026] Figure 5 yes Figure 1 A schematic diagram of the air guide groove in the battery casing viewed from the X direction (I);

[0027] Figure 6 yes Figure 1 Schematic diagram of the air guide groove of the battery casing viewed from the X direction (II);

[0028] Figure 7 yes Figure 1 Schematic diagram of the air guide groove of the battery casing viewed from the X direction (III).

[0029] Explanation of reference numerals in the attached figures

[0030] 100. Explosion-proof hole; 110. Side plate; 111. First plane; 112. Second plane; 120. Reinforcing bracket; 121. Air guide groove; 130. Welded part. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings. The embodiments described herein are merely preferred embodiments of the present invention. Those skilled in the art can conceive of other ways to implement the present invention based on the preferred embodiments, and such other ways also fall within the scope of the present invention.

[0032] Reference Figures 1-7 This application provides a battery casing comprising multiple side plates 110. These side plates 110 are integrally formed into a shell-like structure with openings. The battery casing is used to house the battery cells and injected electrolyte. To promptly release internal pressure in the event of thermal runaway, an explosion-proof valve is typically installed on the battery casing or top cover. This valve opens to release pressure when internal pressure suddenly increases, reducing the risk of battery explosion. However, when the explosion-proof valve is installed on the top cover, during thermal runaway, the expansion or displacement of the battery cells may directly block the valve, preventing timely gas discharge and potentially causing an explosion. Therefore, in this embodiment, an explosion-proof hole 100 is provided on one side plate 110 of the battery casing, penetrating the side plate 110. When the explosion-proof valve is installed on the side of the battery casing through the explosion-proof hole 100, the gas discharge channel is relatively wider and less prone to blockage by cell displacement or other components. Specifically, as... Figure 1 , Figure 3 and Figure 5 As shown, the side plate 110 includes a first plane 111 and a second plane 112 disposed opposite to each other. The second plane 112 is disposed towards the battery cell, that is, the first plane 111 is the outer plane and the second plane 112 is the inner plane. A reinforcing bracket 120 is disposed on the second plane 112 along the outer periphery of the explosion-proof hole 100. The reinforcing bracket 120 protrudes in a direction away from the second plane 112, and the outline of the orthographic projection of the reinforcing bracket 120 on the second plane 112 is consistent with the outer periphery outline of the explosion-proof hole 100.

[0033] Understandably, the reinforcing bracket 120 significantly improves the strength and rigidity of the area surrounding the explosion-proof hole 100 without increasing the overall wall thickness of the side plate 110 of the battery casing. The shape and distribution of the reinforcing bracket 120 effectively disperse stress, preventing stress concentration around the explosion-proof hole 100, thereby reducing the risk of cracking or deformation of the explosion-proof hole 100 due to excessive stress. Furthermore, the reinforcing bracket 120 increases the strength of the casing, preventing deformation when the internal pressure is high, and ensuring stable opening of the explosion-proof valve. Moreover, the reinforcing bracket 120 also supports the battery cell; when the battery cell expands or shifts, the reinforcing bracket 120 blocks the cell, preventing blockage of the explosion-proof hole 100, thus ensuring smooth venting of the explosion-proof hole 100.

[0034] To further enhance gas release capability, in addition to relying on the explosion-proof vent 100, in some embodiments, such as Figure 3 As shown, the reinforcing bracket 120 has two gas guide grooves 121, which do not interfere with each other and the explosion-proof hole 100. The positions of the gas guide grooves 121 and the explosion-proof hole 100 do not intersect; they exist independently. The two gas guide grooves 121 are symmetrically arranged about the center of the reinforcing bracket 120, allowing the high-pressure gas inside the housing to be released to both sides while being discharged through the explosion-proof hole 100, thus appropriately relieving the pressure in the explosion-proof hole 100. Of course, only one gas guide groove 121 can be provided to share the gas guiding function of the explosion-proof hole 100 and improve the gas release efficiency.

[0035] In some embodiments, such as Figure 4 As shown, the outline of the reinforcing bracket 120 in the orthographic projection of the second plane 112 is a rounded rectangle, which includes a straight side and an arc-shaped side. The length of the straight side is greater than the radial length of the arc-shaped side. Both the straight side and the arc-shaped side of the reinforcing bracket 120 are provided with air guide grooves 121. The width of the air guide groove 121 on the straight side is smaller than the width of the air guide groove 121 on the arc-shaped side. The longer length of the straight side and the smaller width of the air guide groove 121 improve the air guiding function of the reinforcing bracket 120 while ensuring that the reinforcing bracket 120 has a longer length to support the battery cell and improve the structural strength around the explosion-proof hole 100 of the housing.

[0036] Optional, such as Figure 5 , Figure 6 and Figure 7 As shown, the depth of the gas guide groove 121 is less than or equal to the height of the reinforcing bracket 120. When the depth of the gas guide groove 121 is equal to the height of the reinforcing bracket 120, the reinforcing bracket 120 forms a completely broken section at the location of the gas guide groove 121, which can increase the gas flow rate. When the depth of the gas guide groove 121 is less than the height of the reinforcing bracket 120, the reinforcing bracket 120 forms a partially broken section at the location of the gas guide groove 121.

[0037] As a preferred embodiment, in some implementations, such as Figure 3 and Figure 5As shown, the protrusion height H of the reinforcing bracket 120 is 0.1mm to 3mm, which can reduce the impact on the internal space of the housing and does not affect the assembly of the battery cells. Specifically, the height H can be 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1mm, 1.5mm, 2mm, 2.5mm, and 3mm, etc. The width D of the outline of the reinforcing bracket 120 in the orthographic projection of the second plane 112 is greater than 0.5mm, such as 0.6mm, 0.8mm, 1mm, etc., which can ensure a certain mechanical strength. The height and width of the reinforcing bracket 120 can ensure the strength of the housing around the explosion-proof hole 100 while minimizing the weight of the reinforcing bracket 120.

[0038] Understandably, an explosion-proof valve is installed at the location of the explosion-proof hole 100 to seal the battery casing and also to release pressure when the internal pressure of the casing becomes too high. The explosion-proof valve is installed on the side plate 110 at the location corresponding to the explosion-proof hole 100 by welding. Figure 1 As shown, the first plane 111 is provided with a welding part 130, which surrounds the outer periphery of the explosion-proof hole 100. Furthermore, the welding part 130 is a submerged structure. The submerged structure constrains the welding position, making the weld more uniform and controllable, reducing defects such as incomplete welds or burn-through, and improving the yield rate. The supporting effect of the submerged structure and the increased welding area together enhance the overall load-bearing capacity of the structure, optimize stress distribution and sealing performance, and extend the service life of the explosion-proof valve and battery housing. Moreover, under extreme operating conditions, the submerged structure can prevent the explosion-proof valve from falling off or shifting, ensuring that the pressure relief process is controllable.

[0039] Another aspect of this application provides a lithium battery, including the aforementioned battery casing. When the internal pressure of the lithium battery suddenly increases, the explosion-proof valve on the battery casing opens, and the internal gas can be released from the explosion-proof valve through the explosion-proof hole 100 on the casing. The strength around the explosion-proof hole 100 of the battery casing is reliable and not easily deformed, which is conducive to the smooth opening of the explosion-proof valve.

[0040] In the description of this utility model, it should be noted that the terms "front," "rear," "left," "right," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and 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 on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] 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.

[0042] The scope of protection of this utility model is defined only by the claims. Thanks to the teachings of this utility model, those skilled in the art will readily recognize that alternative structures to the disclosed structure can be used as feasible alternative implementations, and that the disclosed implementations can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. A battery casing, comprising an explosion-proof hole (100), the explosion-proof hole (100) being disposed through a side plate (110) of the casing; characterized in that, The side plate (110) includes a first plane (111) and a second plane (112) arranged opposite to each other, the second plane (112) facing the battery cell; a reinforcing bracket (120) is provided on the second plane (112) along the outer periphery of the explosion-proof hole (100), the reinforcing bracket (120) protrudes away from the second plane (112), and the outline of the reinforcing bracket (120) in the orthographic projection of the second plane (112) is consistent with the outer periphery outline of the explosion-proof hole (100).

2. A battery casing according to claim 1, characterized in that, The reinforcing bracket (120) has at least one air guide groove (121), and the air guide groove (121) and the explosion-proof hole (100) do not interfere with each other.

3. A battery casing according to claim 2, characterized in that, There are two air guide grooves (121), which are symmetrically arranged about the center of the reinforcing bracket (120).

4. A battery casing according to claim 2, characterized in that, The depth of the air guide groove (121) is less than or equal to the height of the reinforcing bracket (120).

5. A battery casing according to claim 2, characterized in that, The outline of the reinforcing bracket (120) in the orthographic projection on the second plane (112) is a rounded rectangle, which includes a straight side and an arc side. Both the straight side and the arc side of the reinforcing bracket (120) are provided with air guide grooves (121). The width of the air guide groove (121) on the straight side is smaller than the width of the air guide groove (121) on the arc side.

6. A battery casing according to claim 1, characterized in that, The protrusion height H of the reinforcing bracket (120) is 0.1mm to 3mm.

7. A battery casing according to claim 6, characterized in that, The width D of the outline of the reinforcing bracket (120) projected onto the second plane (112) is greater than 0.5 mm.

8. A battery casing according to claim 1, characterized in that, The first plane (111) is provided with a welding part (130), which surrounds the outer periphery of the explosion-proof hole (100).

9. A battery casing according to claim 8, characterized in that, The welded part (130) is a sinking structure.

10. A lithium battery, characterized in that, Includes the battery casing as described in any one of claims 1-9.

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