Pressure relief device and battery pack

Abstract

The invention relates to a pressure relief device and a battery pack. The pressure relief device comprises a pressure relief pipe, a connecting piece and an anti-reflux valve plate, the end of the pressure relief pipe is used for being communicated with the outside of the battery pack, the connecting piece is arranged on the pressure relief pipe and communicated with the pressure relief pipe, and the end, away from the pressure relief pipe, of the connecting piece is used for being communicated with the anti-explosion valve on the single battery. An anti-explosion channel is formed in the connecting piece and comprises a reducing section, and the size of the reducing section is gradually increased from the end close to the anti-explosion valve to the end close to the pressure relief pipe. The anti-reflux valve plate is arranged in the reducing section and used for selectively blocking the anti-explosion channel. The pressure relief device can effectively prevent high-temperature substances from causing thermal influence on surrounding single batteries, reduces the risk of thermal runaway spreading, also prevents conductive substances in the high-temperature substances from diffusing to the surrounding to cause short-circuit accidents, and improves the safety performance of the whole battery pack.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a pressure relief device and a battery pack. Background Technology

[0002] With the continuous expansion of the new energy industry, the application of power batteries in industries such as automobiles, bicycles, wind power energy storage, photovoltaic energy storage, and communication base stations is constantly developing, and the market demand for power batteries is also increasing. In practical applications, the safety of power batteries is an important consideration in the research and development and manufacturing processes. Currently, power batteries mainly use battery packs as the smallest energy storage unit. In related technologies, a battery pack mainly consists of a housing and several individual cells installed inside the housing. These individual cells are connected together in series / parallel via terminal blocks to meet energy storage requirements. To improve the safety performance of the battery pack, it is usually equipped with a pressure relief device. The pressure relief device includes a pressure relief channel located inside the housing and an explosion-proof valve installed on the housing, with the explosion-proof valve connected to the pressure relief channel. When a single cell experiences thermal runaway, the pressure relief valve of the single cell is forced to open due to a sharp increase in internal pressure. The high-temperature, high-pressure gas, electrolyte, and other substances inside the single cell are discharged into the pressure relief channel through the pressure relief valve and finally discharged through the explosion-proof valve.

[0003] The existing technology has the following shortcomings: When a single cell is depressurized, the high-temperature substances discharged can have a thermal impact on other single cells in the surrounding area, which can easily lead to a chain reaction and expand the spread of thermal runaway. Furthermore, the high-temperature substances discharged from the single cell contain carbon black and graphite debris, which can easily cause short circuits in the surrounding circuitry. Summary of the Invention

[0004] The purpose of this invention is to provide a pressure relief device and a battery pack that can reduce the risk of thermal runaway propagation and improve the overall safety of the battery pack.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, a pressure relief device is provided, comprising a pressure relief pipe, a connector, and an anti-backflow valve. One end of the pressure relief pipe is used to communicate with the outside of a battery pack. The connector is disposed on and communicates with the pressure relief pipe. One end of the connector away from the pressure relief pipe is used to communicate with an explosion-proof valve on a single battery cell. The connector has an explosion-proof channel, which includes a variable diameter section. The size of the variable diameter section gradually increases from the end near the explosion-proof valve to the end near the pressure relief pipe. The anti-backflow valve is disposed within the variable diameter section and is used to selectively block the explosion-proof channel.

[0007] As a preferred embodiment of the pressure relief device, the explosion-proof channel further includes a transition section connected to the variable diameter section. The variable diameter section is located between the transition section and the pressure relief pipe, and the size of the transition section gradually decreases from the end near the explosion-proof valve to the end near the pressure relief pipe.

[0008] As a preferred embodiment of the pressure relief device, along the axial direction of the explosion-proof channel, the size of the explosion-proof channel gradually increases from the end near the explosion-proof valve to the end near the pressure relief pipe, and the entire explosion-proof channel forms the variable diameter section. The anti-backflow valve plate is disposed at the end of the explosion-proof channel near the pressure relief pipe.

[0009] As a preferred embodiment of the pressure relief device, the explosion-proof channel further includes a constant diameter section connected to the variable diameter section. The constant diameter section has the same size, the variable diameter section is connected to the pressure relief pipe, and the constant diameter section is used to connect to the explosion-proof valve.

[0010] As a preferred embodiment of the pressure relief device, the anti-backflow valve plate is made of stainless steel, and / or the thickness of the anti-backflow valve plate is 0.4 to 0.6 mm.

[0011] As a preferred embodiment of the pressure relief device, the anti-backflow valve plate is bonded to the connector, and the anti-backflow valve plate can be separated from the connector when the explosion-proof valve is depressurized.

[0012] As a preferred embodiment of the pressure relief device, it further includes a manifold, wherein there are multiple pressure relief pipes, which are spaced apart on the manifold. The manifold is provided with a pipe joint for communicating with the outside of the battery pack, and a one-way valve is provided inside the pipe joint.

[0013] As a preferred embodiment of the pressure relief device, the manifold has an annular structure, and the manifold forms a cavity for accommodating a plurality of the individual batteries.

[0014] As a preferred embodiment of the pressure relief device, the cross-section of the variable diameter section is circular, the maximum diameter of the variable diameter section is L1, the minimum diameter of the variable diameter section is L2, and L1-L2=1~2mm.

[0015] Secondly, a battery pack is also provided, including a housing, individual batteries, and a pressure relief device. A plurality of individual batteries are installed in the housing. An explosion-proof valve is provided on the top surface of each individual battery. A pressure relief channel is formed between the housing and the top surface of the individual batteries. The pressure relief channel is connected to the outside of the housing. The pressure relief device is installed in the pressure relief channel. A connector in the pressure relief device is spaced apart from the explosion-proof valve, and the connector is bonded to the individual batteries with sealant.

[0016] As a preferred embodiment of the battery pack, the distance between the connector and the explosion-proof valve is 0.5 to 1.5 mm.

[0017] As a preferred embodiment of the battery pack, the sealant has a melting point of 200–300°C.

[0018] The advantages of this invention compared to the prior art are:

[0019] The pressure relief device and battery pack of the present invention include a connector on the pressure relief pipe, which connects to an explosion-proof valve. When a single cell experiences thermal runaway, the high-temperature material discharged during pressure relief can enter the pressure relief pipe through the connector and then exit the battery pack through the pipe. Because the pressure relief pipe is spaced a certain distance from the single cell, it helps reduce the thermal impact of the high-temperature material in the pressure relief pipe on surrounding cells. By incorporating an anti-backflow valve within the connector, the valve can seal off surrounding connectors, preventing the high-temperature material in the pressure relief pipe from diffusing to surrounding cells. Therefore, this pressure relief device effectively prevents the high-temperature material from causing thermal impact on surrounding cells, reducing the risk of thermal runaway propagation. It also prevents conductive materials in the high-temperature material from diffusing to the surrounding area and causing short circuits, thus improving the overall safety performance of the battery pack. Attached Figure Description

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a bottom view of the pressure relief device according to an embodiment of the present invention.

[0022] Figure 2 This is a front view of the pressure relief device according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the connector according to an embodiment of the present invention.

[0024] Figure 4 This is a cross-sectional view of the connector according to an embodiment of the present invention.

[0025] Figure 5 This is a cross-sectional view of a connector according to another embodiment of the present invention.

[0026] Figure 6 This is a cross-sectional view of a connector according to another embodiment of the present invention.

[0027] Figure 7 This is an exploded view of the battery pack according to an embodiment of the present invention.

[0028] Figure 8 for Figure 7 Enlarged view of point A in the image.

[0029] Figure 9This is a schematic diagram illustrating the connection between the connector and a single battery cell according to an embodiment of the present invention.

[0030] In the picture:

[0031] 100. Housing; 200. Individual battery; 210. Explosion-proof valve; 300. Pressure relief device; 400. Sealant;

[0032] 1. Pressure relief pipe; 11. 90° elbow; 2. Connecting parts; 20. Explosion-proof passage; 21. Variable diameter section; 22. Equal diameter section; 23. Transition section; 3. Anti-backflow valve plate; 4. Manifold; 41. Receiving cavity; 42. Pipe fitting. Detailed Implementation

[0033] The advantages and features of the present invention, as well as methods of implementing them, will become apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms. These embodiments are provided merely to complete the disclosure of the invention and to enable those skilled in the art to fully understand the scope of the invention, which is defined only by the scope of the claims. The same reference numerals denote the same constituent elements throughout the specification.

[0034] The present invention will now be described in detail with reference to the accompanying drawings.

[0035] like Figure 1 , Figure 4 and Figure 8 As shown, this invention provides a pressure relief device 300 for installation within a battery pack. When a single battery cell 200 within the battery pack experiences thermal runaway, the single battery cell 200 can be depressurized through the pressure relief device 300. The pressure relief device 300 includes a pressure relief pipe 1, a connector 2, and an anti-backflow valve 3. The pressure relief pipe 1 is used to discharge the high-temperature material ejected during the pressure relief of the single battery cell 200. The end of the pressure relief pipe 1 communicates with the outside of the battery pack, allowing the high-temperature material to be discharged to the outside of the battery pack through the pressure relief pipe 1. The connector 2 is used to connect the single battery cells 200, and the number and position of the connector 2 correspond one-to-one with the single battery cells 200. The connector 2 resembles a short pipe, with one end connected to the pressure relief pipe 1 and the other end connected to the explosion-proof valve 210 on the single battery cell 200. The connector 2 has an explosion-proof channel 20, which connects the explosion-proof valve 210 to the pressure relief pipe 1. Specifically, one end of the explosion-proof channel 20 connects to the explosion-proof valve 210, and the other end connects to the pressure relief pipe 1. The explosion-proof channel 20 includes a reducing section 21, the inner diameter of which gradually changes along the axial direction. The size of the reducing section 21 gradually increases from the end near the explosion-proof valve 210 to the end near the pressure relief pipe 1. That is, the reducing section 21 has a structure that is larger at one end and smaller at the other. An anti-backflow valve plate 3 is disposed within the reducing section 21 and is used to selectively block the explosion-proof channel 20.

[0036] It is understood that the anti-backflow valve plate 3 can block the explosion-proof channel 20, meaning that the shape of the anti-backflow valve plate 3 is the same as the cross-sectional shape of the explosion-proof channel 20. The anti-backflow valve plate 3 is installed inside the variable diameter section 21, and the size of the anti-backflow valve plate 3 is larger than the minimum size of the variable diameter section 21, but smaller than the maximum size of the variable diameter section 21. In the initial state, the periphery of the anti-backflow valve plate 3 abuts against the side wall of the variable diameter section 21 to block the entire explosion-proof channel 20. When the single battery 200 is depressurized, the high-pressure gas is discharged from the explosion-proof valve 210 and enters the explosion-proof channel 20. The high-pressure gas pushes the anti-backflow valve plate 3 toward the pressure relief pipe 1, thus opening the explosion-proof channel 20. The high-temperature substance containing the high-pressure gas enters the pressure relief pipe 1 through the explosion-proof channel 20 and is finally discharged from the battery pack through the pressure relief pipe 1. Because the diameter-reducing section 21 is relatively smaller at the end near the explosion-proof valve 210 and relatively larger at the end near the pressure relief pipe 1, the anti-backflow valve plate 3 can only move towards the pressure relief pipe 1 and not towards the explosion-proof valve 210. When one of the individual cells 200 is depressurized, the ejected high-temperature material cannot move towards the end of the individual cell 200 through the nearby connector 2. Therefore, when one of the individual cells 200 is depressurized, it will not cause thermal impact on other nearby individual cells 200, thereby reducing the risk of thermal runaway propagation. At the same time, the high-temperature material is confined within the pressure relief pipe 1, which can also effectively prevent the conductive material in the high-temperature material from spreading to the surroundings and causing a short circuit risk. In addition, since the pressure relief pipe 1 and the individual cell 200 are connected by the connector 2, a certain distance is maintained between the pressure relief pipe 1 and the individual cell 200, allowing the high-temperature material in the pressure relief pipe 1 to stay away from other individual cells 200, reducing the conduction of the heat energy of the high-temperature material to the surrounding individual cells 200.

[0037] Specifically, refer to Figure 3 and Figure 4As shown, the cross-section of the explosion-proof channel 20 is elliptical, and correspondingly, the cross-section of the connector 2 is also elliptical. The dimensions of the explosion-proof channel 20 are the major and minor axes of the corresponding ellipse. The explosion-proof channel 20 also includes a transition section 23, which is connected to the reducing section 21. The reducing section 21 is located near the end of the pressure relief pipe 1, and the transition section 23 is located near the end of the explosion-proof valve 210, that is, the reducing section 21 is located between the transition section 23 and the pressure relief pipe 1. The dimensions of the transition section 23 gradually decrease from the end near the explosion-proof valve 210 to the end near the pressure relief pipe 1. Since the end of the transition section 23 near the explosion-proof valve 210 is relatively large, and the end near the reducing section 21 is relatively small, when pressure relief occurs, high-temperature substances preferentially enter the transition section 23. Since the transition section 23 gradually decreases in size along the flow direction of the high-temperature substances, it is beneficial to increase the injection pressure, which in turn is beneficial to opening the anti-backflow valve plate 3. In this embodiment, the connector 2 is an integral structure. Along the axial direction of the explosion-proof channel 20, the size of the explosion-proof channel 20 gradually increases from the middle to both ends, that is, the explosion-proof channel 20 has a structure that is smaller in the middle and larger at both ends. A variable diameter section 21 is formed at the end of the explosion-proof channel 20 closest to the pressure relief pipe 1, and the anti-backflow valve plate 3 is installed within the variable diameter section 21. A transition section 23 is formed at the end of the explosion-proof channel 20 away from the pressure relief pipe 1. Of course, in other embodiments, when the explosion-proof channel 20 is circular, its size is the diameter of the corresponding circle. When the explosion-proof channel 20 is rectangular, its size is the side length of the corresponding rectangle.

[0038] In another embodiment, refer to Figure 5 As shown, along the axial direction of the explosion-proof channel 20, the size of the explosion-proof channel 20 gradually increases from the end near the explosion-proof valve 210 to the end near the pressure relief pipe 1. The entire explosion-proof channel 20 forms a variable diameter section 21, and the anti-backflow valve plate 3 is disposed at the end of the explosion-proof channel 20 near the pressure relief pipe 1. In this embodiment, the radial cross-section of the explosion-proof channel 20 is trapezoidal. The relatively smaller end of the explosion-proof channel 20 is used to communicate with the explosion-proof valve 210, and the relatively larger end of the explosion-proof channel 20 is used to communicate with the pressure relief pipe 1. Installing the anti-backflow valve plate 3 at the end near the pressure relief pipe 1 can prevent a large amount of high-temperature material from accumulating in the nearby connector 2 during pressure relief, and can keep the high-temperature material as far away from the individual battery 200 as possible, thereby reducing the thermal impact on the surrounding individual batteries 200.

[0039] In another embodiment, referring to Figure 6As shown, the explosion-proof channel 20 includes a variable diameter section 21 and a constant diameter section 22 connected to the variable diameter section 21. The end of the variable diameter section 21 facing away from the constant diameter section 22 is connected to the pressure relief pipe 1, and the end of the constant diameter section 22 facing away from the variable diameter section 21 is used to connect to the explosion-proof valve 210. The constant diameter section 22 has the same size. By setting the end of the variable diameter section 21 facing the explosion-proof valve 210 as a constant diameter section 22, while satisfying the unidirectional movement of the anti-backflow valve plate 3, the size of the explosion-proof channel 20 near the explosion-proof valve 210 can be minimized to ensure that the high-temperature substance has sufficient pressure to push open the anti-backflow valve plate 3.

[0040] Specifically, the anti-backflow valve plate 3 is made of stainless steel. Stainless steel has the characteristics of high strength and good heat resistance, and is not easily deformed at high temperatures. Therefore, when one of the individual cells 200 experiences pressure relief, some of the ejected high-temperature material will enter the nearby connector 2. The anti-backflow valve plate 3 can reliably resist the thermal effects of the high-temperature material, preventing it from diffusing to the corresponding individual cell 200 through the connector 2. To ensure the structural strength of the anti-backflow valve plate 3, its thickness is set to 0.4–0.6 mm. In this embodiment, the specific thickness of the anti-backflow valve plate 3 includes, but is not limited to, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, and 0.6 mm.

[0041] Specifically, the anti-backflow valve plate 3 is bonded to the connector 2. When the explosion-proof valve 210 is depressurized, the anti-backflow valve plate 3 can separate from the connector 2. By bonding the anti-backflow valve plate 3 to the inner wall of the connector 2, the battery pack can be prevented from falling off due to environmental vibration during use. The connector 2 is bonded and fixed to the connector 2 by dispensing adhesive. This not only prevents the anti-backflow valve plate 3 from accidentally falling off, but also allows the high-temperature material to smoothly drive the anti-backflow valve plate 3 to separate from the connector 2 during depressurization.

[0042] Specifically, refer to Figure 1 and Figure 2As shown, the pressure relief device 300 also includes a manifold 4. Multiple pressure relief pipes 1 are provided, arranged in parallel and spaced intervals. The number and position of the pressure relief pipes 1 are adapted to the arrangement of the individual battery cells 200 within the battery pack. Each pressure relief pipe 1 is provided with multiple connectors 2, which are spaced apart along the axial direction of the pressure relief pipe 1. Similarly, the number and position of the connectors 2 are adapted to the arrangement of the individual battery cells 200 within the battery pack. The manifold 4 is used to collect or temporarily store high-temperature substances within the multiple pressure relief pipes 1. The manifold 4 is used to communicate with the outside of the battery pack. The manifold 4 includes a pipe body and a pipe connector 42 disposed on the pipe body. The end of the pipe connector 42 facing away from the pipe body communicates with the outside of the battery pack. A one-way valve is installed inside the pipe connector 42. The one-way valve opens from the inside of the pressure relief device 300 to the outside, satisfying the pressure relief requirement while preventing external gas from entering the pressure relief device 300. The pipe body has a ring-shaped structure, and both ends of the pressure relief pipe 1 are connected to the pipe body and are interconnected. One side of the inner ring of the pipe body forms a receiving cavity 41, which is used to accommodate several individual batteries 200. To facilitate the installation of the individual batteries 200, several individual batteries 200 are pre-assembled together to form a battery module. Steel straps are provided around the battery module to bind and fix the individual batteries 200. By setting the manifold 4 as a ring structure, the end of the battery module near the explosion-proof valve 210 can be inserted into the receiving cavity 41 to fix the individual batteries 200 and further improve the structural strength of the battery module. In this embodiment, the pressure relief pipe 1 includes a straight pipe section in a straight state and 90° elbows 11 at both ends of the straight pipe section. The end of the 90° elbow 11 facing away from the straight pipe section is connected to the pipe body in the manifold 4. A connector 2 is provided on the straight pipe section, and the connector 2 is located on the side of the straight pipe section facing the manifold 4. This structure creates a space between the pressure relief pipe 1 and the manifold 4 to accommodate the battery module, allowing for a greater insertion of one end of the battery module into the manifold 4, thus improving the structural strength of the battery module. Both the manifold 4 and the pressure relief pipe 1 are square tubes. Using a square tube for the manifold 4 increases the depth of the accommodating cavity 41, improving the installation stability of the battery module. Using a square tube for the pressure relief pipe 1 facilitates the installation of the elliptical connector 2, simplifying the manufacturing process. Of course, in other embodiments, the manifold 4 and the pressure relief pipe 1 can also be round tubes.

[0043] Specifically, refer to Figure 4As shown, the cross-section of the reducing section 21 is circular. The end of the reducing section 21 closest to the pressure relief pipe 1 has the largest diameter, which is L1. The end of the reducing section 21 furthest from the pressure relief pipe 1 has the smallest diameter, which is L2, and L1-L2 = 1-2 mm. The difference between the large and small ends of the reducing section 21 reflects the change in the gap between the anti-backflow valve plate 3 and the connecting member 2. During pressure relief, driven by the high-temperature and high-pressure substance, the anti-backflow valve plate 3 moves axially towards the pressure relief pipe 1 along the connecting member 2. When the difference between L1 and L2 is relatively small, the change in the gap between the anti-backflow valve plate 3 and the inner wall of the connecting member 2 during movement is relatively small. The main pressure of the high-temperature and high-pressure substance can be concentrated on the anti-backflow valve plate 3, thereby driving the anti-backflow valve plate 3 to smoothly enter the pressure relief pipe 1, thus opening the explosion-proof channel 20. When the difference between L1 and L2 is relatively large, the gap between the anti-backflow valve plate 3 and the inner wall of the connector 2 changes relatively significantly during movement. Some high-temperature, high-pressure substances will enter the pressure relief pipe 1 through the gap between the anti-backflow valve plate 3 and the connector 2, thus achieving simultaneous pressure relief while the valve is opened. Therefore, in practical applications, the range of the difference between the maximum and minimum diameter of the variable diameter section 21 can be reasonably selected according to specific design specifications. In this embodiment, the difference between the maximum diameter L1 and the minimum diameter L2 of the variable diameter section 21 includes, but is limited to, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm. For example, if the maximum diameter L1 of the variable diameter section 21 is 13.5mm, the maximum diameter L2 of the variable diameter section 21 is 12mm, and the difference between the maximum and minimum diameter of the variable diameter section 21 is 1.5mm.

[0044] like Figures 7 to 9As shown, the present invention also provides a battery pack, including a housing 100, individual batteries 200, and a pressure relief device 300. The housing 100 has a cuboid structure, and a sealed chamber for installing the individual batteries 200 is formed inside the housing 100. The individual batteries 200 are divided into multiple battery modules, and each battery module has multiple individual batteries 200 arranged in rows. The battery modules are installed inside the housing 100. An explosion-proof valve 210 is provided on the top surface of each individual battery 200, and all the explosion-proof valves 210 are arranged in multiple rows, with each row containing multiple explosion-proof valves 210. A pressure relief channel is formed between the top surface of all the individual batteries 200 and the top inner wall of the housing 100, and the pressure relief channel communicates with the outside of the housing 100. Correspondingly, a pressure relief valve is also provided at the connection between the pressure relief channel and the housing 100, and the valve can be opened during pressure relief. The pressure relief device 300 is installed in the pressure relief channel, and each row of explosion-proof valves 210 corresponds to one pressure relief pipe 1. Each connector 2 is correspondingly positioned to one of the explosion-proof valves 210, with each connector 2 facing one explosion-proof valve 210. Connectors 2 and explosion-proof valves 210 are spaced apart, and connector 2 is bonded to the individual battery 200 using sealant 400. In this embodiment, connector 2 is bonded using sealant 400, and the end of connector 2 facing away from the pressure relief pipe 1 is connected to the explosion-proof valve 210. When the individual battery 200 experiences thermal runaway, the high-temperature substance first breaks through the explosion-proof valve 210 and enters the connector 2. Then, the high-temperature substance breaks through the anti-backflow valve 3 and enters the pressure relief pipe 1, finally being discharged outside the housing 100 through the pressure relief pipe 1. A sealant 400 is placed between the connector 2 and the explosion-proof valve 210, with space between them. This serves two purposes: firstly, it ensures the seal between the connector 2 and the individual battery 200; secondly, if the connector 2 fails to conduct, the high-temperature substance can melt the sealant 400, and then enter the pressure relief channel through the gap between the connector 2 and the individual battery 200, allowing the high-temperature substance to release pressure through the pressure relief channel, thus ensuring the reliability of pressure relief. Therefore, by setting up a pressure relief device 300 in the pressure relief channel, high-temperature components are preferentially discharged through the pressure relief device 300, while ensuring the smooth pressure relief of the individual battery 200, to prevent thermal runaway from spreading to surrounding individual batteries 200. Even if the pressure relief device 300 fails, pressure can still be released through the pressure relief channel to ensure the overall safety performance of the battery pack.

[0045] Specifically, the distance between the connector 2 and the explosion-proof valve 210 is 0.5–1.5 mm. In this embodiment, the specific distance between the connector 2 and the explosion-proof valve 210 includes, but is not limited to, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, and 1.5 mm. When the distance between the connector 2 and the explosion-proof valve 210 is small, it can promote the rapid entry of high-temperature substances into the connector 2, preventing high-temperature substances from damaging the sealant 400. When the distance between the connector 2 and the explosion-proof valve 210 is large, it can ensure that there is sufficient clearance between the connector 2 and the explosion-proof valve 210 for high-temperature substances to pass through. In practical applications, the distance between the connector 2 and the explosion-proof valve 210 can be reasonably selected according to the specific design specifications of the battery pack.

[0046] Specifically, the melting point of sealant 400 is 200–300°C. The melting point of sealant 400 should be controlled within a suitable range so that, in the event of failure of the pressure relief device 300, the high-temperature substance can quickly melt the sealant 400 to achieve pressure relief.

[0047] The beneficial effects of this embodiment are as follows: By providing a connector 2 on the pressure relief pipe 1, which is used to connect with the explosion-proof valve 210, when a single battery cell experiences thermal runaway, the high-temperature material discharged during pressure relief can enter the pressure relief pipe 1 through the connector 2 and be discharged outside the battery pack through the pressure relief pipe 1. Since the pressure relief pipe 1 is spaced a certain distance from the single battery cell 200, it helps to reduce the thermal impact of the high-temperature material in the pressure relief pipe 1 on the surrounding single batteries cell 200. By providing an anti-backflow valve plate 3 in the connector 2, the anti-backflow valve plate 3 can be used to block the surrounding connector 2, thereby preventing the high-temperature material in the pressure relief pipe 1 from diffusing to the surrounding single batteries cell 200 through the connector 2. Therefore, this pressure relief device can effectively prevent the high-temperature material from causing thermal impact on the surrounding single batteries cell 200, reduce the risk of thermal runaway propagation, and also prevent conductive materials in the high-temperature material from diffusing to the surrounding area and causing short circuit accidents, thus improving the safety performance of the entire battery pack.

[0048] Although embodiments of the invention have been described above with reference to the accompanying drawings, the invention is not limited to the above embodiments, but can be made in various forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical spirit or essential characteristics of the invention. Therefore, it should be understood that the above embodiments are exemplary in all respects and not restrictive.

Claims

1. A pressure relief device, characterized in that, The relief pipe (1) is used for communicating with the outside of the battery pack, the connecting piece (2) is arranged on the relief pipe (1) and communicates with the relief pipe (1), one end of the connecting piece (2) away from the relief pipe (1) is used for communicating with the explosion-proof valve (210) on the single battery (200), the connecting piece (2) has an explosion-proof channel (20) therein, the explosion-proof channel (20) comprises a variable-diameter section (21), the size of the variable-diameter section (21) gradually increases from one end close to the explosion-proof valve (210) to one end close to the relief pipe (1), the anti-backflow valve piece (3) is arranged in the variable-diameter section (21), and the anti-backflow valve piece (3) is used for selectively plugging the explosion-proof channel (20).

2. The pressure relief device of claim 1, wherein, The explosion-proof channel (20) further comprises a transition section (23), the transition section (23) is connected with the variable-diameter section (21), the variable-diameter section (21) is located between the transition section (23) and the relief pipe (1), and the size of the transition section (23) gradually decreases from one end close to the explosion-proof valve (210) to one end close to the relief pipe (1). In the axial direction of the explosion-proof channel (20), the size of the explosion-proof channel (20) gradually increases from the middle part to both ends, and one end of the explosion-proof channel (20) close to the relief pipe (1) forms the variable-diameter section (21).

3. The pressure relief device of claim 1, wherein, In the axial direction of the explosion-proof channel (20), the size of the explosion-proof channel (20) gradually increases from one end close to the explosion-proof valve (210) to one end close to the relief pipe (1), the entire explosion-proof channel (20) forms the variable-diameter section (21), and the anti-backflow valve piece (3) is arranged at one end of the explosion-proof channel (20) close to the relief pipe (1).

4. The pressure relief device of claim 1, wherein, The explosion-proof channel (20) further comprises an equal-diameter section (22) connected with the variable-diameter section (21), the equal-diameter section (22) has the same size, the variable-diameter section (21) communicates with the relief pipe (1), and the equal-diameter section (22) is used for communicating with the explosion-proof valve (210).

5. The pressure relief device of claim 1, wherein, The anti-backflow valve piece (3) is a stainless steel piece, and / or the thickness of the anti-backflow valve piece (3) is 0.4-0.6 mm.

6. The pressure relief device of claim 1, wherein, The anti-backflow valve piece (3) is bonded with the connecting piece (2), and the anti-backflow valve piece (3) can be separated from the connecting piece (2) when the explosion-proof valve (210) is relieved.

7. The pressure relief device of any one of claims 1 to 6, wherein, Further comprising a collecting pipe (4), the relief pipe (1) is a plurality of, a plurality of the relief pipe (1) is connected on the collecting pipe (4) at intervals, the collecting pipe (4) is used for communicating with the outside of the battery pack, and the collecting pipe (4) is provided with a one-way valve.

8. The pressure relief device of claim 7, wherein, The collecting pipe (4) is annular, and the collecting pipe (4) surrounds an accommodation cavity (41) for accommodating a plurality of single batteries (200).

9. The pressure relief device of any one of claims 1 to 6, wherein, The variable-diameter section (21) has a circular cross section, the maximum diameter of the variable-diameter section (21) is L1, the minimum diameter of the variable-diameter section (21) is L2, and L1-L2=1-2 mm.

10. A battery pack, characterized by, The device includes a housing (100), individual batteries (200), and a pressure relief device (300) as described in any one of claims 1 to 9. A plurality of individual batteries (200) are installed inside the housing (100). An explosion-proof valve (210) is provided on the top surface of each individual battery (200). A pressure relief channel is formed between the housing (100) and the top surface of each individual battery (200). The pressure relief channel is connected to the outside of the housing (100). The pressure relief device (300) is installed inside the pressure relief channel. The connector (2) in the pressure relief device (300) is spaced apart from the explosion-proof valve (210), and the connector (2) is bonded to the individual battery (200) by a sealant (400).

11. The battery pack of claim 10, wherein, The distance between the connector (2) and the explosion-proof valve (210) is 0.5 to 1.5 mm.

12. The battery pack of claim 10, wherein, The melting point of the sealant (400) is 200-300℃.

Images