Pressure relief assembly, battery shell and battery

Abstract

The invention relates to a pressure relief assembly, a battery shell and a battery, and belongs to the technical field of batteries. The pressure relief assembly comprises a valve plate and a patch, the valve plate is provided with a nick to form a weak layer, the weak layer is provided with a penetrating hollow part, and the patch covers the nick and extends into the hollow part and is made of a flame-retardant temperature sensitive material (such as TPE silica gel and the like). When the air pressure reaches a first set value, a second set value or the temperature reaches a third set value, the patch is separated or melted, and rapid pressure relief is achieved. The battery shell comprises a pressure relief assembly and a pressure relief opening; the pressure relief assembly is arranged on the outer surface, far away from the positive and negative poles, of the shell; the battery comprises the shell, an end cover and a pole group, according to the design, the pressure relief sensitivity is improved through an air pressure and temperature dual-trigger mechanism, manufacturing defects are reduced, and the structural reliability is enhanced; the design of the hollow part improves the connection effect and the exhaust efficiency, effectively avoids accidents such as battery swelling and explosion, prolongs the service life of the battery, and improves the overall safety performance.

Description

Pressure relief assembly, battery casing and battery Technical Field

[0001] This application relates to the field of battery technology, and in particular to pressure relief components, battery casings, and batteries. Background Technology

[0002] In the field of battery technology, especially in applications involving high-energy-density batteries such as power batteries, battery safety has always been a key concern in the research and development and production process. Under abnormal operating conditions such as overcharging, over-discharging, internal short circuits, or external physical damage, batteries generate a large amount of gas and heat internally, causing a sharp increase in internal pressure and temperature. If the internal pressure is not released and the temperature is not controlled in a timely and effective manner, the battery may bulge, leak, or even cause serious safety accidents such as explosions and fires, posing a huge threat to the life and property safety of users.

[0003] Traditional battery pressure relief devices typically employ grooves of a certain depth on the valve plate, creating a weak layer at these grooves. When the internal pressure of the battery reaches a certain value, this weak layer ruptures, releasing pressure. However, this design presents several problems in practical applications. Firstly, to meet the minimum strength requirements of explosion-proof valves, the groove depth is usually shallow, resulting in a relatively thick weak layer. This leads to higher opening pressures and insufficient sensitivity of the explosion-proof valve. When the internal pressure or temperature of the battery abnormally increases, it cannot respond quickly enough to expel gas in time, increasing the risk of battery damage or explosion. Secondly, during the manufacturing process, the stamping of the grooves may cause uneven thickness, creating the risk of localized rupture, affecting the normal operation of the explosion-proof valve, and reducing manufacturing yield and product reliability. Furthermore, traditional pressure relief devices only consider air pressure and lack effective measures to address safety issues caused by temperature changes, making it difficult to meet the high safety requirements of modern batteries under complex operating conditions. Therefore, developing a battery pressure relief device that can effectively address both abnormal air pressure and temperature changes, improving pressure relief sensitivity and reliability, has become an urgent technical problem to be solved in the current battery technology field. Summary of the Invention

[0004] Therefore, it is necessary to address the technical problems of insufficient sensitivity, low manufacturing yield, and inability to effectively cope with temperature changes leading to poor safety in traditional battery pressure relief devices by providing pressure relief components, battery casings, and batteries. This would enable the battery to respond quickly when the internal air pressure or temperature rises abnormally, achieve rapid pressure relief through a dual triggering mechanism, improve pressure relief sensitivity and reliability, reduce manufacturing defects, enhance structural stability, effectively avoid safety accidents such as battery bulging, leakage, and explosion, extend battery life, and improve overall safety performance.

[0005] A first aspect of the present invention provides a pressure relief assembly, comprising: a valve plate having a notch on one side in the thickness direction, thereby forming a weak layer in the thickness direction at the notch location of the valve plate; the weak layer having at least one perforated portion in the thickness direction; and a patch having a first portion and a second portion, the first portion having at least one second portion disposed on the side of the first portion near the weak layer in the thickness direction, the first portion covering the end face of the weak layer near the notch in the thickness direction, and the second portion extending into the perforated portion; the pressure relief assembly satisfies at least one of the following a) and b): a) when the internal air pressure of the battery casing reaches a first set value P1, the patch can detach from the notch; when the internal air pressure of the battery casing reaches a second set value P2, the weak layer tears, P2>P1; b) the melting point of the patch is less than the melting point of the valve plate. Through the dual design of the notch and the perforated portion, combined with the temperature-sensitive material patch, a dual response mechanism to air pressure and temperature is achieved. When the internal pressure or temperature of the battery rises abnormally, the patch can quickly detach or melt, exposing the perforated area for rapid pressure relief. This design not only improves the sensitivity of pressure relief but also enhances the reliability of the explosion-proof valve, avoiding the risk of battery damage or explosion due to excessive pressure or temperature. Simultaneously, the patch design also improves manufacturing yield and reduces the risk of uneven thickness and localized cracking caused by scoring and stamping.

[0006] In other embodiments, the first portion has the same shape as the projection of the notch in the thickness direction, and the second portion corresponds to the position of the cutout portion, and the second portion has the same shape as the projection of the cutout portion in the thickness direction. This ensures that the patch can fit tightly onto the notch and the cutout portion, improving the connection effect and sealing performance. This design prevents gas leakage and ensures that the patch can quickly detach or melt under high temperature or high pressure, achieving rapid pressure relief.

[0007] In other embodiments, in the thickness direction, the dimensional difference between the second portion and the cutout portion is 0mm ± 0.05mm, and the thickness of the first portion is less than the depth of the notch, ensuring a tight fit between the patch and the cutout portion, improving the overall connection effect, and preventing abnormal detachment. Simultaneously, the thickness of the first portion being less than the notch depth ensures a minimum pressure relief, allowing the patch to quickly detach or melt when the gas pressure increases, thus improving the sensitivity and reliability of the explosion-proof valve.

[0008] In other embodiments, the patch is a flame-retardant temperature-sensitive material, including one or more of TPE silicone, high-density polyethylene, ABS, PPS, and silicone pressure-sensitive adhesive. Selecting materials with excellent flame-retardant properties and temperature sensitivity allows the patch to melt rapidly when the internal temperature of the battery abnormally rises, exposing the perforated portion and achieving rapid pressure relief. Simultaneously, the insulating properties of these materials ensure battery safety, preventing the risk of fire or explosion caused by short circuits.

[0009] In other embodiments, the patch is melt-cooled and then deposited into the notch. This melt-cooling injection method ensures a tight fit between the patch and the notch and cutout, improving the connection effect and sealing performance. Simultaneously, this design also enhances the overall strength of the explosion-proof valve, enabling it to remain stable under high-pressure gas and avoiding the risk of failure due to insufficient strength.

[0010] In other embodiments, the patch is disposed within the notch using a snap-fit ​​or adhesive method. For materials whose performance is affected after melting and cooling, snap-fit ​​or adhesive methods are more suitable. This method uses precision equipment to accurately attach the patch to the corresponding position of the notch, ensuring a good connection and sealing performance, while avoiding manufacturing defects and safety risks caused by changes in material properties.

[0011] In other embodiments, the notches are annular, and there are at least four hollowed-out portions, which are evenly and equidistantly distributed in the weak layer. The annular notch design increases the connection area with the patch, improving the connection effect. Simultaneously, the evenly and equidistant distribution of multiple hollowed-out portions further enhances the patch's connection effect, enabling the explosion-proof valve to meet the minimum opening pressure while avoiding the risk of failure due to accidental opening. This design not only improves the reliability of the explosion-proof valve but also extends its service life.

[0012] A second aspect of the present invention provides a battery housing comprising the pressure relief assembly described in any of the preceding claims, and further comprising a pressure relief port for mounting the pressure relief assembly. The design of the pressure relief port allows gas to be smoothly discharged during pressure relief, preventing safety risks caused by gas blockage. This design improves the safety and reliability of the battery housing.

[0013] A third aspect of the present invention provides a battery comprising a battery casing as described in any of the preceding claims, further comprising an end cap sealing the battery casing and an electrode assembly disposed within the battery casing. By applying a battery casing containing a pressure relief assembly to the battery, the overall performance and safety of the battery are improved. Through a dual triggering mechanism of air pressure and temperature, the battery can respond rapidly to abnormal increases in internal air pressure or temperature, achieving rapid pressure relief, effectively preventing safety accidents such as battery bulging and explosion, and extending battery life. Attached Figure Description

[0014] Figure 1 is an exploded view of the pressure relief component in this invention.

[0015] Figure 2 is a top view of the pressure relief assembly in this invention.

[0016] Figure 3 is a top view of the valve plate in this invention.

[0017] Figure 4 is a cross-sectional view along direction A in Figure 2.

[0018] Figure 5 is a schematic diagram of the valve plate and the patch being separated in Figure 4.

[0019] Figure 6 is an exploded view of the battery in this invention.

[0020] Reference numerals: 10, pressure relief assembly; 20, battery casing; 30, electrode assembly; 40, end cap; 100, valve plate; 110, notch; 120, weak layer; 130, cutout; 200, patch; 210, first part; 220, second part. Detailed Implementation

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0022] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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 application.

[0023] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0027] As shown in Figures 1-5, Embodiment 1 discloses a pressure relief assembly 10, including a valve plate 100 and a patch 200. The valve plate 100 has a notch 110, and a hollow portion 130 penetrating the valve plate 100 is formed on the end face of the notch 110 in the thickness direction. The patch 200 is mounted on the valve plate 100. The patch 200 is made of a temperature-sensitive material, which melts when the temperature reaches a certain level, exposing the hollow portion 130 for gas release. Simultaneously, when the pressure is sufficiently high, it can also cause the notch 110 area to fracture, improving the gas release efficiency. This not only improves the sensitivity of the pressure relief assembly 10 but also increases its reliability. When the internal pressure or temperature of the battery abnormally increases, it can respond quickly. Through the dual action of the hollow portion 130 and the notch 110, it ensures rapid gas release, preventing battery explosion. Furthermore, the patch 200 uses a temperature-sensitive material that can melt at high temperatures, further enhancing the adaptability and safety of the pressure relief assembly 10.

[0028] Specifically, in this embodiment, the valve plate 100 has a notch 110 on one side in the thickness direction, and the remaining portion of the valve plate 100 at the notch 110 in the thickness direction forms a weak layer 120. That is, the weak layer 120 is formed after the notch 110 is made on the valve plate 100. In this embodiment, the notch 110 is deeper than that of the valve plate 100 without the patch 200 in the conventional technology, which means that the corresponding weak layer 120 is thinner. In the conventional technology, the notch 110 depth of the power battery is generally 0.1mm-0.3mm to ensure the thickness of the weak layer 120 and meet the minimum strength requirements of the explosion-proof valve; while in this application... The depth of the notch 110 can be increased to 0.3mm-0.5mm, further reducing the thickness of the weak layer 120. This is because the presence of the patch 200, combined with the weak layer 120, strengthens its overall strength. If the thickness of the weak layer 120 were increased as in related technologies, the opening pressure would increase under the action of the patch 200. This means that when the pressure inside the battery reaches the pressure required to open the explosion-proof valve, it might fail to open, causing the valve to malfunction. By increasing the depth of the notch 110, the thickness of the weak layer 120 is reduced, thereby lowering the opening pressure of the explosion-proof valve and making it more sensitive. However, simply thinning the weak layer 120 might lead to insufficient strength. Therefore, the design of the patch 200 enhances the overall strength of the weak layer 120. This design not only improves the sensitivity of pressure relief but also ensures that the explosion-proof valve can open normally when needed, avoiding the risk of battery damage or explosion due to excessive pressure. Furthermore, this design makes the manufacturing process of the explosion-proof valve more flexible, allowing the depth of the notch 110 and the material of the patch 200 to be adjusted according to actual needs to meet the safety requirements of different batteries.

[0029] Furthermore, due to the presence of patch 200, even if the notch 110 experiences uneven thickness during stamping, leading to localized cracking, it will not affect the use of the explosion-proof valve. During the manufacturing process, stamping of the notch 110 may result in uneven thickness, creating a risk of localized cracking. However, due to the presence of patch 200, even if localized cracking occurs at the notch 110, patch 200 can still maintain the integrity of the overall structure, preventing gas leakage. This design significantly improves the manufacturing yield and reliability of the explosion-proof valve, reducing safety risks caused by manufacturing defects.

[0030] As shown in Figures 1 and 4-5, in this embodiment, the patch 200 is mounted on the valve plate 100. The patch 200 covers the end face of the groove 110 in the thickness direction and extends into the hollow portion 130, that is, the patch 200 covers the bottom wall of the groove 110 and also blocks the hollow portion 130. The design of the patch 200 not only covers the bottom wall of the groove 110 but also extends into the hollow portion 130, ensuring that gas cannot pass through under normal conditions. This design allows the patch 200 to quickly detach or melt under high temperature or high pressure, thereby exposing the hollow portion 130 and achieving rapid pressure relief. In addition, the patch 200 also plays a sealing role, preventing gas leakage inside the battery under normal conditions and improving the safety and reliability of the battery.

[0031] Specifically, in this embodiment, the patch 200 has a first portion 210 and a second portion 220. At least one second portion 220 is provided on one side of the first portion 210 in the thickness direction. The two portions are an integral structure. The first portion 210 has the same shape as the projection of the notch 110 in the thickness direction, thus the first portion 210 can cover the bottom wall of the notch 110. The second portion 220 corresponds to the position of the hollow portion 130, and the second portion 220 has the same shape as the projection of the hollow portion 130 in the thickness direction, allowing the second portion 220 to fit snugly into the hollow portion 130, improving the connection between the patch 200 and the weak layer 120 and enhancing the overall sealing effect. The design of the first portion 210 and the second portion 220 of the patch 200 allows the patch 200 to adhere tightly to the notch 110 and the hollow portion 130, improving the connection effect and sealing performance. This design not only prevents gas leakage, but also ensures that patch 200 can quickly detach or melt under high temperature or high pressure, achieving rapid pressure relief.

[0032] In this embodiment, patch 200 is a flame-retardant temperature-sensitive material, including one or more of TPE silicone, high-density polyethylene, ABS, PPS, and silicone pressure-sensitive adhesive. These materials all possess insulating properties and generally have a melting temperature greater than 150°C, and can melt at excessively high temperatures. These materials were chosen for patch 200 because of their excellent flame-retardant properties and temperature sensitivity. When the internal temperature of the battery rises abnormally, these materials can melt rapidly, exposing the perforated portion 130, achieving rapid pressure relief. Simultaneously, their insulating properties ensure battery safety, preventing the risk of fire or explosion caused by short circuits. Furthermore, the melting temperature of these materials is generally greater than 150°C, ensuring their stability under normal operating temperatures and preventing malfunctions due to temperature increases.

[0033] In this embodiment, the patch 200 is injected into the notch 110 using a melt-cooling method. That is, the aforementioned material, such as TPE silicone, is liquid at high temperature. After the valve plate 100 is stamped to form the notch 110 and the corresponding hollow portion 130, the molten patch 200 is then cast into the corresponding position and cooled to return to a solid state. To ensure a perfect match between the second part 220 of the patch 200 and the hollow portion 130, support is needed at the lower end of the valve plate 100 to prevent the molten patch 200 from flowing out. At the same time, if the entire valve plate 100 is kept horizontally distributed, the upper surface of the patch 200 can be made flatter. Even if the patch 200 has uneven thickness after stamping, the overall strength can be improved by setting the patch 200, preventing the explosion-proof valve from failing. The melt-cooling injection method ensures a tight fit between the patch 200 and the notch 110 and the hollow portion 130, improving the connection effect and sealing performance. Meanwhile, the support and horizontal distribution design ensures the stability of patch 200 during the cooling process, preventing manufacturing defects caused by patch 200 flow. Furthermore, this design improves the overall strength of the explosion-proof valve, enabling it to remain stable when facing high-pressure gas and avoiding the risk of failure due to insufficient strength.

[0034] In another embodiment, the patch 200 is disposed within the notch 110 using a snap-fit ​​or adhesive method. That is, after the notch 110 and the cutout 130 are formed, the corresponding patch 200 is attached to the corresponding position of the notch 110 using precision equipment, thereby completing the connection between the patch 200 and the explosion-proof valve disc 100. This method is suitable for materials whose performance is affected after melting and cooling. For some materials whose performance is affected after melting and cooling, using a snap-fit ​​or adhesive method to set the patch 200 is more suitable. This method uses precision equipment to accurately attach the patch 200 to the corresponding position of the notch 110, ensuring connection effectiveness and sealing performance. At the same time, it also avoids manufacturing defects and safety risks caused by changes in material properties.

[0035] Internal pressure and temperature are two closely related parameters of a battery. When a battery malfunctions, such as overcharging, over-discharging, or an internal short circuit, both pressure and temperature will rise. Therefore, the design of the pressure relief component 10 must consider the effects of both pressure and temperature. In this embodiment, the pressure relief component 10, through the design of the notch 110 and the patch 200, can respond simultaneously to increases in pressure and temperature, achieving rapid pressure relief and ensuring battery safety.

[0036] The pressure relief component satisfies at least one of the following a) and b): a) When the internal air pressure of the battery casing reaches a first set value P1, the patch can detach from the notch 110; when the internal air pressure of the battery casing reaches a second set value P2, the weak layer 120 tears, P2>P1; the internal air pressure of the battery casing reaching the first set value is the minimum pressure for the conventional explosion-proof valve to activate, and the patch 200 can detach from the notch 110 in advance. Because the patch 200 is attached to the notch 110 and the hollow part 130, the design allows the explosion-proof valve to respond quickly when the air pressure increases, preventing the risk of battery damage or explosion due to excessive air pressure. At the same time, the pre-detachment of the patch 200 also avoids the risk of explosion-proof valve failure due to a sudden increase in air pressure; as the internal air pressure of the battery casing gradually increases, when the hollow part 130 can no longer meet the requirements, the weak layer 120 tears, thereby improving the efficiency of air relief.

[0037] (b) When the temperature reaches the third set value (when the internal temperature is greater than 150°C), the patch 200 can melt, and the melting point of the patch 200 is greater than the melting point of the valve plate 100. The patch 200 can be pre-melted and can quickly detach from the perforated part 130 after melting, so that the explosion-proof valve can respond quickly when the temperature rises, preventing battery damage or fire risk caused by excessive temperature. At the same time, even if the temperature does not reach the melting point, the softening of the patch 200 makes it easier to detach, improving the pressure relief effect. In addition, setting the explosion-proof valve on the bottom wall or side wall of the battery housing 20 also facilitates the detachment of the patch 200 and the discharge of gas.

[0038] In this embodiment, at least one perforated portion 130 penetrating the valve plate 100 is provided in the thickness direction of the weak layer 120. The perforated portion 130 in this embodiment has the following advantages: First, the perforated portion 130 improves the connection effect with the patch 200, preventing the patch 200 from detaching, thus ensuring that the thinned weak layer 120, after being bonded to the patch 200, meets the minimum strength requirements. Second, the perforated portion 130 increases the connection area between the patch 200 and the valve plate 100, improving the connection effect and preventing the patch 200 from detaching. Simultaneously, it also ensures that the thinned weak layer 120, reinforced by the patch 200, still meets the minimum strength requirements, ensuring the reliability of the explosion-proof valve.

[0039] Secondly, the patch 200 comes into contact with the high-temperature gas through the hollow part 130, which improves the heating effect. At the same time, after melting at high temperature, it can flow out from the hollow part 130. The valve plate 100 in this application is usually set on the bottom wall or side wall of the battery housing 20. Even if it is set on the top wall, the patch 200 is an insulating material, and it will not affect the exhaust effect when it flows into the battery housing 20.

[0040] Thirdly, the patch 200, through the perforated portion 130, comes into direct contact with the high-pressure gas, allowing for a rapid response to the gas's impact force. When the patch 200 detaches, the gas can be released through the perforated portion 130, meeting the venting requirements. Simultaneously, the presence of the perforated portion 130 maintains the structural stability of the valve plate 100, ensuring its stability when facing high-pressure gas. Furthermore, when the internal pressure is excessive, after the patch 200 is forced open, the perforated portion 130 makes the weak layer 120 easier to tear, thereby improving subsequent venting efficiency. This design not only enhances the pressure relief capacity of the explosion-proof valve but also extends its service life.

[0041] In this embodiment, the dimensional difference between the second part 220 and the hollowed-out part 130 in the thickness direction is 0mm ± 0.05mm, meaning that the second part 220 of the patch 200 and the hollowed-out part 130 basically match, improving the overall connection effect and preventing abnormal detachment. The dimensional difference between the second part 220 and the hollowed-out part 130 is controlled within a very small range, ensuring a tight fit between the patch 200 and the hollowed-out part 130. The thickness of the first part 210 is less than the depth of the notch 110, ensuring a minimum pressure relief. This is because if the first part 210 of the patch 200 is too thick, the friction between the remaining notches 110 will increase, preventing timely response to abnormal internal battery pressure, leading to explosion-proof failure. This design ensures that the patch 200 can quickly detach or melt when the pressure increases. If the first part 210 is too thick, it will increase the friction between it and the notch 110, preventing the patch 200 from responding promptly to abnormal internal battery pressure, leading to explosion-proof failure. Therefore, this design ensures the sensitivity and reliability of the explosion-proof valve.

[0042] In this embodiment, the notches 110 are annular, and there are at least four hollowed-out portions 130. These hollowed-out portions 130 are evenly and equidistantly distributed on the weak layer 120. The annular notch design 110 increases the connection area with the patch 200, improving the connection effect. Simultaneously, the evenly and equidistant distribution of the hollowed-out portions 130 further enhances the connection effect of the patch 200, enabling the explosion-proof valve to meet the minimum opening pressure while avoiding the risk of failure due to accidental opening. This design not only improves the reliability of the explosion-proof valve but also extends its service life.

[0043] In other embodiments, the notches 110 are linear, including one or a combination of straight lines and curves, wherein the cutouts 130 are evenly distributed on the linear notches 110, thereby being applied to elongated explosion-proof valves.

[0044] Example 2: This example discloses a battery casing 20, which includes the pressure relief assembly 10 from Example 1, and also includes a pressure relief port for mounting the pressure relief assembly 10. The design of the pressure relief port allows gas to be smoothly discharged during pressure relief, preventing safety risks caused by gas blockage. This design improves the safety and reliability of the battery casing 20.

[0045] In this embodiment, the positive and negative terminals are generally located on the top wall of the battery housing 20. In this embodiment, the pressure relief component 10 is located on the bottom wall of the battery housing 20. This is mainly because the groove 110 on the valve plate 100 faces the outside of the battery housing 20, and the patch 200 is connected to the valve plate 100. When the patch 200 melts, it can be quickly detached. If the pressure relief component 10 is located on the same side as the positive and negative terminals, that is, on the top wall, then the melted patch 200 will enter the interior of the battery housing 20. Although the patch 200 is made of insulating material, some materials can also promote battery reaction or block the pressure relief port, increasing the overall risk. If a flame-retardant material is used, and it does not block the pressure relief port after melting, then the patch 200 can also be located on the top wall.

[0046] Example 3 This example discloses a battery, which includes a battery housing 20 as described in Example 2, an end cap 40 that seals the battery housing 20, and an electrode assembly 30 placed inside the battery housing 20. The battery housing 20 from Example 2 is applied to the battery, and the pressure relief assembly 10 from Example 1 is also used, which improves the overall performance and safety of the battery.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A pressure relief assembly, applied to a battery casing, characterized in that, include: The valve plate has a groove on one side in the thickness direction, thereby forming a weak layer, and at least one hollow portion penetrating the weak layer is formed in the thickness direction of the weak layer. A patch having a first portion embedded in a notch and a second portion embedded in a cutout, wherein at least one second portion is provided on one side of the first portion in the thickness direction; the pressure relief assembly satisfies at least one of the following a) and b): a) when the internal air pressure of the battery casing reaches a first set value P1, the patch can detach from the notch; when the internal air pressure of the battery casing reaches a second set value P2, the weak layer tears, P2>P1; b) the melting point of the patch is less than the melting point of the valve plate.

2. The pressure relief assembly according to claim 1, characterized in that: The first part has the same shape as the projection of the engraving in the thickness direction, the second part corresponds to the position of the hollow part, and the second part has the same shape as the projection of the hollow part in the thickness direction.

3. The pressure relief assembly according to claim 2, characterized in that: In the thickness direction, the dimensional difference between the second part and the hollowed-out part is 0mm ± 0.05mm, and the thickness of the first part is less than the depth of the groove.

4. The pressure relief assembly according to claim 1, characterized in that: The patch is made of a flame-retardant temperature-sensitive material, including one or more of TPE silicone, high-density polyethylene, ABS, PPS and silicone pressure-sensitive adhesive.

5. The pressure relief assembly according to claim 4, characterized in that: The patch is placed into the groove using a melt-cooling method.

6. The pressure relief assembly according to claim 4, characterized in that: The patch is set within the groove by snap-fit ​​or adhesive.

7. The pressure relief assembly according to claim 1, characterized in that: The engravings are in the form of a ring, and there are at least four hollowed-out sections, which are evenly and equidistantly distributed in the weak layer.

8. A battery casing, characterized in that: Includes the pressure relief assembly as described in any one of claims 1-7.

9. The battery casing according to claim 8, characterized in that: It also includes a pressure relief port for installing pressure relief components.

10. A battery, characterized in that: It includes the battery casing as described in any one of claims 8-9, and further includes an end cap that closes the battery casing and an electrode assembly disposed within the battery casing.

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