Battery shell and battery

Abstract

The utility model discloses a battery shell and a battery, and relates to the technical field of batteries. The battery shell comprises a shell body and a sealing assembly, a liquid injection hole is formed in the shell body, and the sealing assembly comprises a transition piece and an anti-explosion piece; the transition piece is in sealed connection with the shell body, and a through hole communicated with the liquid injection hole is formed in the transition piece; the explosion-proof piece covers one side, far away from the liquid injection hole, of the through hole, and the explosion-proof piece is hermetically connected with the transition piece; the sealing assembly is configured to enable the anti-explosion piece to crack or enable the joint of the transition piece and the anti-explosion piece to be broken when the internal pressure of the shell body exceeds a preset pressure threshold value. According to the battery shell and the battery disclosed by the invention, the sealing function and the pressure relief and explosion-proof function of the liquid injection hole are realized through a simpler structure, the cost is relatively low, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of batteries, in particular to a battery shell and a battery. BACKGROUND

[0002] With the increasing maturity of lithium ion battery technology, lithium ion batteries have a wide range of applications in various fields, and their safety performance is increasingly valued. The premise for a battery to have good safety performance is to ensure that it has good sealing performance.

[0003] In the related art, a shell of a lithium ion battery usually has a liquid injection hole at the top, and electrolyte is injected into the shell through the liquid injection hole. After the liquid injection is completed, a sealing pin is used to plug the liquid injection hole, and the sealing pin is laser packaged with the shell to achieve overall sealing. At the same time, a pressure relief valve needs to be arranged on the battery shell to blow off to relieve pressure when the gas in the battery reaches a predetermined burst pressure value, so as to avoid high-pressure explosion events.

[0004] However, the sealing function of the liquid injection hole and the pressure relief explosion-proof function need two processes to be realized, which is high in cost and low in efficiency. CONTENT OF THE UTILITY MODEL

[0005] Therefore, the application provides a battery shell and a battery, which have a relatively simple structure for realizing the sealing function of the liquid injection hole and the pressure relief explosion-proof function, fewer assembly process numbers, thus reducing the cost and improving the production efficiency.

[0006] The application specifically adopts the following technical solutions:

[0007] The application provides a battery shell, which comprises a shell body and a sealing assembly, the shell body is provided with a liquid injection hole, and the sealing assembly comprises a transition piece and an explosion-proof piece.

[0008] The transition piece is in sealing connection with the shell body, and the transition piece is provided with a through hole in communication with the liquid injection hole.

[0009] The explosion-proof piece is located on a side of the through hole away from the liquid injection hole and covers the through hole, and the explosion-proof piece is in sealing connection with the transition piece.

[0010] The sealing assembly is configured to cause the explosion-proof piece to crack or the connection between the transition piece and the explosion-proof piece to break when the internal pressure of the shell body exceeds a preset pressure threshold.

[0011] Optionally, the transition piece comprises a transition layer connected with the explosion-proof piece, and the materials of the part of the shell body provided with the liquid injection hole, the transition layer and the explosion-proof piece are different from each other.

[0012] The structural strength of the explosion-proof member is less than the structural strength of the part of the shell body provided with the liquid injection hole, the structural strength of the transition member, and the connecting strength of the shell body and the transition member; and / or,

[0013] The connecting strength of the transition layer and the explosion-proof member is less than the structural strength of the part of the shell body provided with the liquid injection hole, the structural strength of the transition member, and the connecting strength of the shell body and the transition member.

[0014] Optionally, the material of the part of the shell body provided with the liquid injection hole is steel or an alloy thereof; and / or,

[0015] The material of the transition layer is silver or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, or a mixture of at least two of the above metals; and / or,

[0016] The material of the explosion-proof member is aluminum or an alloy thereof.

[0017] Optionally, the connecting area of the explosion-proof member and the transition layer is less than or equal to the surface area of the surface of the transition layer close to the explosion-proof member.

[0018] Optionally, the inner edge of the connection between the explosion-proof member and the transition layer has a spacing with the through hole; and / or,

[0019] The outer edge of the connection between the explosion-proof member and the transition layer has a spacing with the outer edge of the transition layer.

[0020] Optionally, the explosion-proof member is a cover-shaped structure with an inner cavity, and the inner cavity of the explosion-proof member communicates with the inside of the shell body through the through hole and the liquid injection hole.

[0021] Optionally, the explosion-proof member is a circumferentially symmetric structure, and the central axis of the explosion-proof member, the central axis of the through hole, and the central axis of the liquid injection hole coincide.

[0022] Optionally, a weak pattern is provided on the explosion-proof member, wherein the structural strength of the weak pattern is less than the structural strength of the remaining part of the explosion-proof member except the weak pattern.

[0023] Optionally, the transition member further comprises a base layer, the transition member is sealingly connected with the shell body through the base layer, and the material of the base layer is the same as that of the shell body.

[0024] Optionally, the transition layer is a plating layer formed on the base layer, and the thickness of the transition layer ranges from 3 to 10 μm.

[0025] The battery provided by the embodiment of the present application comprises the battery shell of the above aspect and a battery cell installed in the battery shell.

[0026] The battery shell provided by the embodiment of the present application integrates the explosion-proof pressure relief function and the sealing function of the liquid injection hole in one part, i.e., the sealing assembly, which can be sealingly connected with the shell body of the battery shell, thereby ensuring good sealing of the inside of the battery and ensuring long-term stable operation of the battery. Meanwhile, the sealing assembly further comprises an explosion-proof member covering the through hole communicated with the liquid injection hole, when the internal pressure of the battery shell exceeds the preset pressure threshold, the explosion-proof member can be cracked, or the connection between the explosion-proof member and the transition member can be broken, thereby releasing the pressure inside the battery shell, playing a role of explosion-proof pressure relief. Therefore, the battery shell provided by the embodiment of the present application simultaneously realizes the sealing function of the liquid injection hole and the explosion-proof pressure relief function with a single part, thereby simplifying the structure, reducing the number of assembly processes, reducing the cost, improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 is a structural schematic diagram of a battery shell provided by the embodiment of the present application;

[0029] Figure 2 is Figure 1 is a sectional structural schematic diagram of the battery shell in FIG. 1 along the A-A line;

[0030] Figure 3 is a structural schematic diagram of a sealing assembly provided by the embodiment of the present application;

[0031] Figure 4 is a position schematic diagram of the connection between the explosion-proof member and the transition layer provided by the embodiment of the present application;

[0032] Figure 5 is a structural schematic diagram of an explosion-proof member provided by the embodiment of the present application;

[0033] Figure 6 is Figure 2 is an enlarged structural diagram of the sealing assembly in FIG. 2;

[0034] Figure 7 is a structural schematic diagram of another sealing assembly provided by the embodiment of the present application;

[0035] Figure 8 is a structural schematic diagram of another sealing assembly provided by an embodiment of the present application;

[0036] Figure 9 is a structural schematic diagram of another sealing assembly provided by an embodiment of the present application;

[0037] Figure 10 is a structural schematic diagram of another sealing assembly provided by an embodiment of the present application.

[0038] Reference signs:

[0039] 1, shell body; 11, liquid injection hole;

[0040] 2, sealing assembly; 21, transition piece; 211, through hole; 212, transition layer; 2121, outer edge; 2122, surface; 213, base layer; 22, explosion-proof piece; 221, connection; 2211, inner edge; 2212, outer edge; 222, inner cavity; 223, weak pattern. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0042] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0043] The embodiments of the present application provide a battery shell, which is generally applied to a battery with electrolyte, such as a lithium ion battery.

[0044] Figure 1 The appearance of a battery shell provided by an embodiment of the present application is shown, Figure 2 The cross-sectional structure of the battery shell obtained after cutting along the A-A line in Figure 1 is shown. As shown in Figure 2As shown, the battery shell includes a shell body 1 and a sealing assembly 2. Among them, the shell body 1 is provided with a liquid injection hole 11; the sealing assembly 2 includes a transition piece 21 and an anti-explosion piece 22, the transition piece 21 is in sealing connection with the shell body 1, and the transition piece 21 is provided with a through hole 211 in communication with the liquid injection hole 11; the anti-explosion piece 22 is covered on the side of the through hole 211 away from the liquid injection hole 11, and is covered on the through hole 211, and the anti-explosion piece 22 is in sealing connection with the transition piece 21. Among them, the sealing assembly 2 is configured to cause the anti-explosion piece 22 to crack, or cause the connection 221 of the transition piece 21 and the anti-explosion piece 22 to break, when the internal pressure of the shell body 1 exceeds a preset pressure threshold.

[0045] In the embodiments of the present application, the cracking of the anti-explosion piece 22 or the breaking of the connection 221 of the transition piece 21 and the anti-explosion piece 22 is also referred to as the "valve opening" action.

[0046] Therefore, the battery shell provided by the embodiments of the present application integrates the anti-explosion pressure relief function and the sealing function of the liquid injection hole 11 (hereinafter referred to as the "liquid injection hole 11 sealing function") on the sealing assembly 2, which can be in sealing connection with the shell body 1 of the battery shell, thereby ensuring good sealing of the battery interior and ensuring long-term stable operation of the battery; at the same time, the sealing assembly 2 also includes the anti-explosion piece 22 covered on the through hole 211 in communication with the liquid injection hole 11, when the internal pressure of the battery shell exceeds a preset pressure threshold, the anti-explosion piece 22 can crack, or the connection 221 of the anti-explosion piece 22 and the transition piece 21 can break, thereby releasing the pressure inside the battery shell, playing a role in pressure relief and anti-explosion. Therefore, the battery shell provided by the embodiments of the present application realizes the liquid injection hole 11 sealing function and the pressure relief and anti-explosion function at the same time with a single part, so the structure is simplified, and the single part is convenient for storage and transportation, in the subsequent process flow of battery manufacturing, the part is assembled to the shell body 1 only needs one process, so the number of assembly processes is reduced, the cost is reduced, and the production efficiency is improved.

[0047] In order to make the technical solutions and advantages of the present application clearer, the following will combine the accompanying drawings to further describe the technical solutions and advantages of the present application. Figures 1-10 The battery shell provided by the embodiments of the present application is further introduced and explained.

[0048] The battery shell provided by the embodiments of the present application includes a shell body 1 and a sealing assembly 2. The shell body 1 is a hollow cavity structure, and the inside of the shell body 1 can be installed with an electric core for storing and releasing electric energy. The shape of the shell body 1 can be set according to actual needs, for example, it can be a rectangular body, a cylindrical body, a special-shaped body or other shapes, Figure 1 A rectangular body-shaped shell body 1 is shown. Continue to refer to Figure 1The top of the shell body 1 is usually provided with a liquid injection hole 11, which communicates the inside of the shell body 1 with the outside, and electrolyte can be injected into the inside of the shell body 1 through the liquid injection hole 11. In practice, the number, shape, size and other parameters of the liquid injection hole 11 can be set according to actual needs. For example, the number of the liquid injection hole 11 is one, and the cross-sectional shape of the liquid injection hole 11 is circular.

[0049] The sealing assembly 2 is used to seal the liquid injection hole 11 after the electrolyte is injected into the inside of the shell body 1, so as to realize the overall sealing of the battery. At the same time, the sealing assembly 2 can also play a role in pressure relief and explosion prevention, that is, when the pressure inside the shell body 1 exceeds a preset pressure threshold, part of the gas inside the shell body 1 is discharged to play a role in pressure relief and prevent the battery from exploding.

[0050] The sealing assembly 2 needs to ensure that the liquid injection hole 11 can be completely sealed. Generally, the outer contour shape of the sealing assembly 2 is adapted to the shape of the liquid injection hole 11. Figure 3 、 Figure 7 、 Figure 8 、 Figure 9 and Figure 10 respectively show the shapes of several sealing assemblies 2 provided by the embodiments of the present application. For example, when the liquid injection hole 11 is a circular hole, a sealing assembly 2 with a circular outer contour shape as shown in Figure 3 can be used to seal it.

[0051] Take the sealing assembly 2 shown in Figure 3 as an example. Referring to Figure 3 , the sealing assembly 2 includes a transition piece 21 and an explosion-proof piece 22, the transition piece 21 is connected with the shell body 1, and the explosion-proof piece 22 is connected with the transition piece 21. In order to ensure the sealing of the battery, the connection between the transition piece 21 and the shell body 1, and the connection 221 between the explosion-proof piece 22 and the transition piece 21 all need to be sealed, for example, welding, using a sealing ring to connect, etc.

[0052] In the embodiments of the present application, the part that plays a role in pressure relief is the explosion-proof piece 22, and the material of the explosion-proof piece 22 is quite different from that of the shell body 1. Therefore, in order to ensure the realizability and easy operability of the connection between them, the transition piece 21 is used as a transition medium for their connection in the embodiments of the present application. The transition piece 21 can reduce the connection difficulty between the explosion-proof piece 22 and the shell body 1, that is, it is easy to connect with the explosion-proof piece 22 and the shell body 1, and after connection, it can ensure good connection firmness and sealing.

[0053] When the internal pressure of the shell body 1 exceeds the preset pressure threshold after the sealing assembly 2 seals the liquid injection hole 11, the explosion-proof member 22 will be cracked under the gas pressure in the shell body 1, or the connection part 221 of the explosion-proof member 22 and the transition member 21 will be broken under the gas pressure in the shell body 1 to discharge the gas, thereby playing a pressure relief role to avoid serious harm caused by battery explosion.

[0054] In order to make the gas in the shell body 1 flow smoothly to the position in contact with the explosion-proof member 22, so as to open the explosion-proof member 22 to make it crack or open the connection part 221 of the explosion-proof member 22 and the transition member 21 when the internal pressure of the shell body 1 is too large, a through hole 211 can be arranged on the transition member 21, which is in communication with the liquid injection hole 11 to ensure smooth flow of the gas, thereby ensuring smooth implementation of the pressure relief and explosion-proof function.

[0055] Optionally, as shown in Figure 2 The hole area of the through hole 211 on the transition member 21 is greater than or equal to the hole area of the liquid injection hole 11, and the edge of the liquid injection hole 11 coincides with or is located within the edge of the through hole 211, so that when the internal pressure of the shell body 1 changes rapidly, the gas flow on both sides of the liquid injection hole 11 and the through hole 211 can flow rapidly and evenly, thereby improving the pressure relief response capability of the sealing assembly 2.

[0056] In some embodiments of the present application, the pressure relief and explosion-proof function of the explosion-proof member 22 can be realized based on the material properties thereof. As shown in Figure 3 For example, the transition member 21 can be in a plate shape, and in the plate thickness direction, the transition member 21 can be a single-layer structure or a multi-layer structure, where multi-layer means at least two layers. The transition member 21 includes a transition layer 212, where when the transition member 21 is a single-layer structure, the transition member 21 is entirely the transition layer 212; and when the transition member 21 is a multi-layer structure, the layer of the transition member 21 close to the explosion-proof member 22 and connected with the explosion-proof member 22 is the transition layer 212.

[0057] The materials of the part of the shell body 1 provided with the liquid injection hole 11, the transition layer 212, and the explosion-proof member 22 are different from each other.

[0058] In one example, the structural strength of the explosion-proof member 22 is less than the structural strength of the part of the shell body 1 provided with the liquid injection hole 11, less than the structural strength of the transition member 21, and less than the connection strength of the shell body 1 and the transition member 21 (i.e., the strength of the connection part of the shell body 1 and the transition member 21). In this way, when the internal pressure of the shell body 1 exceeds the preset pressure threshold, the explosion-proof member 22 will crack preferentially to the shell body 1, the transition member 21, and the connection part of the shell body 1 and the transition member 21.

[0059] In another example, the connection strength of the transition piece 21 and the explosion-proof piece 22 (i.e. the strength of the connection 221 between the transition piece 21 and the explosion-proof piece 22) is less than the structural strength of the portion of the shell body 1 where the liquid injection hole 11 is provided, and is less than the structural strength of the transition piece 21, and is also less than the connection strength of the shell body 1 and the transition piece 21 (i.e. the strength of the connection between the shell body 1 and the transition piece 21). In this way, when the internal pressure of the shell body 1 exceeds the preset pressure threshold, the connection 221 between the transition piece 21 and the explosion-proof piece 22 will crack preferentially to the shell body 1, the transition piece 21, and the connection between the shell body 1 and the transition piece 21.

[0060] It should be noted that in the above two examples, the structural strength of the explosion-proof piece 22 can be less than the connection strength of the transition piece 21 and the explosion-proof piece 22, in which case the explosion-proof piece 22 will crack preferentially to the connection 221 between the transition piece 21 and the explosion-proof piece 22; or the structural strength of the explosion-proof piece 22 can be equal to the connection strength of the transition piece 21 and the explosion-proof piece 22, in which case the explosion-proof piece 22, the transition piece 21, and the connection 221 between the transition piece 21 and the explosion-proof piece 22 can crack simultaneously, or one of them can crack randomly; or the structural strength of the explosion-proof piece 22 can be equal to the connection strength of the transition piece 21 and the explosion-proof piece 22, in which case the connection 221 between the transition piece 21 and the explosion-proof piece 22 can crack preferentially to the explosion-proof piece 22.

[0061] Therefore, by using the above two examples, it can be ensured that when the internal pressure of the shell body 1 exceeds the preset pressure threshold, the explosion-proof piece 22 will crack, or the connection 221 between the transition piece 21 and the explosion-proof piece 22 will crack, thereby ensuring the feasibility of pressure relief and effectively avoiding high-pressure explosion of the battery.

[0062] Optionally, the material of the portion of the shell body 1 where the liquid injection hole 11 is provided can be steel or an alloy thereof, such as stainless steel, etc. In an example, the shell body 1 can be a steel shell made entirely of stainless steel for strength requirements and cost considerations.

[0063] Optionally, the material of the transition layer 212 can be silver or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, or a mixture of at least two of the above metals. In an example, the transition layer 212 can be made of copper or an alloy thereof for ease of welding and cost considerations.

[0064] When the shell body 1 and the transition layer 212 of the above materials need to be sealed and connected, welding can be used, such as ultrasonic welding.

[0065] Optionally, the material of the explosion-proof piece 22 is aluminum or an alloy thereof, such as soft aluminum, aviation aluminum, etc. In an example, the explosion-proof piece 22 can be made of soft aluminum for explosion-proof effect considerations.

[0066] When the sealing connection of the explosion-proof piece 22 and the transition layer 212 of the above-mentioned materials needs to be performed, a welding method can be used, for example, laser welding.

[0067] It should be noted that in the embodiments of the present application, the preset pressure threshold is set by the technician according to the actual demand, and the preset pressure threshold is directly related to the structural strength of the explosion-proof piece 22 or the connection strength of the explosion-proof piece 22 and the transition layer 212. The technician can adjust the preset pressure threshold by changing the material, thickness, hardness and other parameters of the explosion-proof piece 22, and the connection process of the explosion-proof piece 22 and the transition layer 212. Therefore, the sealing assembly 2 provided in the embodiments of the present application can set the preset pressure threshold according to the required battery valve opening pressure, which is more flexible and practical, and the valve opening response capability and valve opening response speed are also better.

[0068] In addition, in the related art, the explosion-proof port (also known as the pressure relief valve structure) on the battery shell is usually a thinning structure formed on the battery steel shell using a laser or punching process. When the gas pressure inside the battery steel shell reaches a predetermined burst pressure value, the thinning structure bursts, allowing the internal gas to be discharged from there. However, due to the material of the steel shell and the forming process of the thinning structure, the lower limit of the burst pressure value is about 2.5 MPa, which cannot reach a lower level, thus seriously affecting the valve opening response speed. However, in the embodiments of the present application, when the explosion-proof piece 22 is made of aluminum or its alloy, since the tensile strength of aluminum and its alloy is lower than that of steel and its alloy, the valve opening response time of the aluminum explosion-proof piece 22 is shorter, and at the same time, the lower limit of the predetermined pressure threshold of the aluminum explosion-proof piece 22 can reach a level of less than or equal to 0.1 MPa, for example, 0.05 MPa in the test, thus effectively reducing the valve opening pressure and improving the valve opening response speed.

[0069] Optionally, the corresponding predetermined pressure threshold range of the sealing assembly 2 provided in the embodiments of the present application is 0.1-1 MPa, within which range the sealing assembly 2 has stable valve opening performance and good reliability.

[0070] In some embodiments of the present application, as shown in Figure 4 It should be noted that in the embodiments of the present application, the preset pressure threshold is set by the technician according to the actual demand, and the preset pressure threshold is directly related to the structural strength of the explosion-proof piece 22 or the connection strength of the explosion-proof piece 22 and the transition layer 212. The technician can adjust the preset pressure threshold by changing the material, thickness, hardness and other parameters of the explosion-proof piece 22, and the connection process of the explosion-proof piece 22 and the transition layer 212. Therefore, the sealing assembly 2 provided in the embodiments of the present application can set the preset pressure threshold according to the required battery valve opening pressure, which is more flexible and practical, and the valve opening response capability and valve opening response speed are also better.

[0071] For example, to facilitate understanding, Figure 4 In the embodiments of the present application, the connection area of the connection part 221 of the explosion-proof piece 22 and the transition layer 212 is less than or equal to the surface area of the surface 2122 of the transition layer 212 close to the explosion-proof piece 22. Making the surface area of the surface 2122 of the transition layer 212 close to the explosion-proof piece 22 larger can improve the convenience and ease of operation when welding the explosion-proof piece 22, while ensuring that the transition layer 212 and the explosion-proof piece 22 can achieve sufficient welding strength and good welding sealing performance.Figure 4 The inner edge 2211 of the connection 221 between the explosion-proof component 22 and the transition layer 212 is spaced from the through hole 211; the outer edge 2212 of the connection 221 between the explosion-proof component 22 and the transition layer 212 is spaced from the outer edge 2121 of the transition layer 212. This ensures that the explosion-proof component 22 welded to the transition layer 212 has a sufficiently good welding effect with the transition layer 212, and does not obstruct the flow of gas through the through hole 211.

[0072] Furthermore, in some embodiments, the explosion-proof component 22 is a cap-like structure with an inner cavity 222, the inner cavity 222 of which is connected to the interior of the shell body 1 through a through hole 211. By designing the explosion-proof component 22 as a cap-like structure, the airflow inside the shell body 1 can be well balanced and dispersed after flowing out through the through hole 211, and then act comprehensively on the inner surface of the explosion-proof component 22. This avoids the phenomenon that the explosion-proof component 22 cracks when the internal pressure of the shell body 1 does not reach the preset pressure threshold, as the airflow immediately acts on a local area of ​​the explosion-proof component 22 after flowing out through the through hole 211.

[0073] Optionally, the cross-sectional area of ​​the inner cavity 222 of the explosion-proof component 22 is larger than the hole area of ​​the through hole 211, thus ensuring that the airflow can be well dispersed and balanced after flowing out of the through hole 211, avoiding valve opening errors caused by the large pressure in the local area when the airflow flows out of the through hole 211.

[0074] like Figure 5 As shown, in some embodiments of this application, the explosion-proof component 22 has a circumferentially symmetrical structure, and the central axis of the explosion-proof component 22 coincides with the central axis of the through hole 211 and the central axis of the injection hole 11.

[0075] In this field, a "circumferentially symmetrical structure" refers to a structure that is symmetrical in the circumferential direction. It can generally be understood that when the structure rotates around its central axis, its shape, size, and stress distribution are the same in all directions.

[0076] By concentrically arranging the explosion-proof component 22, the through hole 211, and the injection hole 11, it can be ensured that after the airflow inside the shell body 1 flows through the injection hole 11 and the through hole 211 to the inner cavity 222 of the explosion-proof component 22, the explosion-proof component 22 can be subjected to uniform force. Therefore, the reliability and accuracy of the sealing assembly 2 in opening the valve when the internal pressure of the shell body 1 exceeds the preset pressure threshold are further ensured.

[0077] In some embodiments of this application, such as Figure 10As shown, a weak pattern 223, such as a strip-shaped groove, a circular groove, an array of multiple grooves, and other groove patterns, can also be arranged on the explosion-proof piece 22. The structural strength of the weak pattern 223 is less than that of the rest of the explosion-proof piece 22 except the weak pattern 223. Therefore, when the internal pressure of the shell body 1 exceeds the pressure that the weak pattern 223 can withstand, the weak pattern 223 will crack before the rest of the explosion-proof piece 22, thereby further reducing the preset pressure threshold corresponding to the explosion-proof piece 22, i.e., reducing the valve opening pressure of the battery, improving the reliability of the valve opening, and ensuring the safety of the battery in use.

[0078] It should be noted that in the related art, to form a thinning structure of the battery steel shell, the material hardness of the steel shell is limited, and laser engraving or punching process is generally used, which is complex and requires high precision of the equipment, thereby resulting in high cost. Moreover, to achieve a lower burst pressure value, the residual thickness of the steel shell needs to be engraved to less than 0.02 mm. Since the thickness is difficult to control in industry, the burst pressure value of the battery steel shell in the related art fluctuates greatly, and the range of the burst pressure values of the battery steel shells in the same batch is generally greater than or equal to 0.5 MPa.

[0079] However, in the present embodiment, since the weak pattern 223 is formed on aluminum or its alloy, the material hardness is relatively low, and the punching process can be used, which is simple, easy to operate, has high forming efficiency, and is lower in cost. Moreover, since the punching process is mature and stable, the preset pressure threshold corresponding to the manufactured explosion-proof piece 22 can be kept in a small fluctuation range, and the range of the preset pressure thresholds corresponding to a group of explosion-proof pieces 22 in the same batch is generally less than or equal to 0.1 MPa, thereby greatly improving the valve opening stability of the explosion-proof piece 22.

[0080] In some embodiments of the present application, when the transition piece 21 has a multi-layer structure, the layer close to and connected with the shell body 1 is a base layer 213, which is made of the same material as the shell body 1 and is sealingly connected with the shell body 1.

[0081] Generally, when welding the transition layer 212 and the shell body 1, since the two welding objects are made of different materials, it is more difficult to weld than the same material, and thus the welding process (such as ultrasonic welding) has a relatively large effect on the atomic arrangement at the welding position of the shell body 1, which may affect the mechanical properties of the shell body 1. Therefore, the transition piece 21 in the present embodiment further includes a base layer 213 made of the same material as the shell body 1, so that the base layer 213 and the shell body 1 can be welded by other welding processes (such as laser welding), thereby minimizing the effect on the mechanical properties of the shell body 1.

[0082] As to the connecting manner of the transition layer 212 and the base layer 213, exemplarily, the two can be welded by ultrasonic welding process to realize the connection; or the two can be connected by means of other intermediate medium layer; or the transition layer 212 can be formed on the base layer 213 by mechanical plating, hot-dip plating or electroplating process.

[0083] Optionally, when the transition layer 212 is a plating layer formed on the base layer 213, the thickness of the transition layer 212 ranges from 3 to 10 μm. By controlling the transition layer 212 within the above thickness range, it can be ensured that the transition layer 212 can play a good soldering role, and the cost is relatively low.

[0084] The application also provides a battery, which comprises the battery shell according to any one of the above embodiments, and a battery cell installed in the battery shell.

[0085] The battery provided by the application can reduce the number of manufacturing processes during the battery manufacturing stage, achieve relatively high manufacturing efficiency, and reduce the cost, by using the battery shell according to the above embodiments. In addition, when the internal pressure of the battery is greater than the preset pressure threshold, the battery can be relieved in time to prevent the battery from exploding under high pressure, and has good use safety.

[0086] In the description of the application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "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 application and simplifying the description, and do not indicate or imply 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 application. In addition, the terms "first", "second", "third" 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 the technical features indicated.

[0087] The above is only for the convenience of those skilled in the art to understand the technical solutions of the application, and does not limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A battery casing, characterized in that, The battery casing includes a casing body (1) and a sealing assembly (2). The casing body (1) is provided with a liquid injection hole (11). The sealing assembly (2) includes a transition piece (21) and an explosion-proof piece (22). The transition piece (21) is sealed to the shell body (1), and the transition piece (21) is provided with a through hole (211) communicating with the injection hole (11); The explosion-proof component (22) is located on the side of the through hole (211) away from the injection hole (11) and covers the through hole (211). The explosion-proof component (22) is sealed to the transition component (21). The sealing assembly (2) is configured to cause the explosion-proof component (22) to crack or the connection (221) between the transition component (21) and the explosion-proof component (22) to break when the internal pressure of the shell body (1) exceeds a preset pressure threshold.

2. The battery casing according to claim 1, characterized in that, The transition member (21) includes a transition layer (212) connected to the explosion-proof member (22). The shell body (1) has a portion with the injection hole (11). The transition layer (212) and the explosion-proof member (22) are made of different materials, wherein: The structural strength of the explosion-proof component (22) is less than the structural strength of the portion of the shell body (1) where the injection hole (11) is provided, the structural strength of the transition component (21), and the connection strength between the shell body (1) and the transition component (21); and / or, The connection strength between the transition layer (212) and the explosion-proof component (22) is less than the structural strength of the portion of the shell body (1) where the injection hole (11) is provided, the structural strength of the transition component (21), and the connection strength between the shell body (1) and the transition component (21).

3. The battery casing according to claim 2, characterized in that, The portion of the shell body (1) with the injection hole (11) is made of steel or its alloy; and / or, The transition layer (212) is made of silver or an alloy thereof, copper or an alloy thereof, nickel or an alloy thereof, or a mixture of at least two of these metals; and / or, The explosion-proof component (22) is made of aluminum or its alloy.

4. The battery casing according to claim 2 or 3, characterized in that, The connection area of ​​the connection point (221) between the explosion-proof component (22) and the transition layer (212) is less than or equal to the surface area of ​​the transition layer (2122) near the explosion-proof component (22).

5. The battery casing according to claim 4, characterized in that, The inner edge (2211) of the connection (221) between the explosion-proof component (22) and the transition layer (212) has a gap with the through hole (211); and / or, The outer edge (2212) of the connection (221) between the explosion-proof component (22) and the transition layer (212) has a gap with the outer edge (2121) of the transition layer (212).

6. The battery casing according to claim 4, characterized in that, The explosion-proof component (22) is a cover-shaped structure with an inner cavity (222). The inner cavity (222) of the explosion-proof component (22) is connected to the interior of the shell body (1) through the through hole (211) and the liquid injection hole (11).

7. The battery casing according to claim 6, characterized in that, The explosion-proof component (22) has a circumferentially symmetrical structure, and the central axis of the explosion-proof component (22), the central axis of the through hole (211), and the central axis of the injection hole (11) coincide.

8. The battery casing according to claim 6, characterized in that, The explosion-proof component (22) is provided with a weak pattern (223), wherein the structural strength of the weak pattern (223) is less than the structural strength of the rest of the explosion-proof component (22) except for the weak pattern (223).

9. The battery casing according to claim 2 or 3, characterized in that, The transition piece (21) further includes a base layer (213), which is sealed to the shell body (1) through the base layer (213). The base layer (213) is made of the same material as the shell body (1).

10. The battery casing according to claim 9, characterized in that, The transition layer (212) is a coating formed on the base layer (213), and the thickness of the transition layer (212) ranges from 3 to 10 μm.

11. A battery, characterized in that, The battery includes a battery casing as described in any one of claims 1-10, and a battery cell installed within the battery casing.

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