Battery pack

Abstract

This utility model belongs to the field of battery technology and discloses a battery pack, including a liquid cooling plate and battery cells abutting against the liquid cooling plate. The liquid cooling plate has a liquid cooling channel for circulating coolant. The liquid cooling plate has a first side connected to the battery cells, and a buffer groove is provided on the first side. A first explosion-proof valve connected to the liquid cooling channel is provided at the bottom of the buffer groove. The battery cells have a second explosion-proof valve, and the first and second explosion-proof valves are arranged opposite each other at a distance. The battery pack of this utility model, through the buffer groove of the liquid cooling plate, provides a certain buffer space between the first and second explosion-proof valves, so that thermal runaway gas can promptly and sequentially explode the second and first explosion-proof valves, avoiding excessive impact force required for the first and second explosion-proof valves to come into contact, which could affect the release of thermal runaway gas from the battery cells. This reduces the possibility of battery cell explosion and effectively improves the safety of the battery cells and the battery pack.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery pack. Background Technology

[0002] Lithium-ion batteries, as a new type of rechargeable battery, have advantages such as high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and environmental friendliness. They have broad application prospects in portable electrical appliances, power tools, large-scale energy storage, and electric transportation power supplies. However, when lithium-ion batteries experience thermal runaway, they produce a large amount of gas. If this gas cannot be expelled in time, it can accumulate to a certain volume, causing the battery to explode or even spread to other batteries, leading to a series of uncontrolled events.

[0003] With the development of new energy vehicles, the requirements for controlling battery thermal runaway risk are becoming increasingly stringent. Currently, battery thermal runaway is generally divided into two paths: internal and external. The internal path refers to thermal runaway caused by chemical reactions within a single cell. When the internal temperature of a single cell continues to rise, the vaporized electrolyte rushes out of the cell's explosion-proof valve, and the thermal runaway electrolyte gas enters the external path (within the battery pack). At this time, the battery pack's fire suppression system responds simultaneously. Using sensor detection results, the controller drives the fire extinguishing device to spray extinguishing agent to prevent the electrolyte gas from contacting external oxygen and igniting. However, when a single cell experiences thermal runaway, while flame retardant methods can indeed extinguish the open flame, the chemical reactions within the cell continue, and the temperature will still rise. Upon contact with oxygen, reignition can occur, making it difficult to completely extinguish the thermal runaway of a single cell and reducing the safety of the battery pack. Utility Model Content

[0004] The purpose of this utility model is to provide a battery pack with a simple structure, in which the liquid cooling plate can dissipate heat from the battery cell, and at the same time, when the battery cell experiences thermal runaway, the first explosion-proof valve can be ruptured to extinguish the thermal runaway of the battery cell by the liquid cooling medium in the liquid cooling channel of the liquid cooling plate, thus preventing the thermal runaway from spreading.

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

[0006] A battery pack is provided, including a liquid cooling plate and a battery cell abutting against the liquid cooling plate. The liquid cooling plate has a liquid cooling channel for circulating coolant. The liquid cooling plate has a first side surface connected to the battery cell. A buffer groove is recessed on the first side surface. A first explosion-proof valve connected to the liquid cooling channel is provided at the bottom of the buffer groove. The battery cell has a second explosion-proof valve. The first explosion-proof valve and the second explosion-proof valve are arranged opposite to each other at a distance.

[0007] As a preferred embodiment of the battery pack, the first explosion-proof valve includes a weak part, the minimum distance between the side of the weak part adjacent to the battery cell and the cavity wall of the liquid cooling channel is D1, and the minimum distance between the bottom of the buffer groove and the cavity wall of the liquid cooling channel is D2, where D1 = (0.6~0.8)D2.

[0008] As a preferred embodiment of the battery pack, the first explosion-proof valve is a thermoplastic sealing plug, and the bottom of the buffer groove is provided with a connecting hole that communicates with the liquid cooling channel, and the thermoplastic sealing plug is engaged in the connecting hole.

[0009] As a preferred embodiment of the battery pack, the hot-melt sealing plug includes a first sealing part and a second sealing part. The first sealing part is inserted into the connecting hole and is abutted against the hole wall of the connecting hole. Two second sealing parts are spaced apart on the first sealing part. The two second sealing parts abut against the bottom of the buffer groove and the side wall of the liquid cooling channel where the connecting hole is opened, respectively.

[0010] As a preferred embodiment of the battery pack, the first side is recessed and has a positioning groove, one end of the battery cell with the second explosion-proof valve is inserted into the positioning groove, and the buffer groove is recessed at the bottom of the positioning groove.

[0011] As a preferred embodiment of the battery pack, the battery pack further includes a sealing ring, wherein the bottom of the positioning groove is recessed around the central axis of the first explosion-proof valve, and the sealing ring is engaged within the first sealing groove, the sealing ring abutting against the battery cell; and / or,

[0012] A second sealing groove is recessed around the central axis of the positioning groove, and the sealing ring is engaged in the second sealing groove, with the sealing ring abutting against the outer peripheral wall of the battery cell.

[0013] As a preferred embodiment of the battery pack, the contact area between the battery cell and the bottom of the positioning groove is S1, and the area of ​​the end face of the battery cell where the second explosion-proof valve is located is S2.

[0014] As a preferred embodiment of the battery pack, the battery pack includes multiple cell groups arranged along a first direction, each cell group including multiple cells arranged along a second direction, the liquid cooling channel including a first liquid cooling channel, the liquid cooling plate having an inlet, an outlet and multiple first liquid cooling channels, the inlet and the outlet being respectively located on both sides of the liquid cooling plate along the second direction, all the first liquid cooling channels being spaced apart along the first direction, the length of the first liquid cooling channels extending along the second direction, and all the first liquid cooling channels being connected to the inlet and the outlet at both ends along the second direction, each cell group correspondingly having one first liquid cooling channel, and each first liquid cooling channel having multiple first explosion-proof valves spaced apart along the second direction, the first direction being perpendicular to the second direction.

[0015] As a preferred embodiment of the battery pack, the liquid cooling channel includes a second liquid cooling channel. Each battery cell is provided with a set of liquid cooling channels. Each set of liquid cooling channels includes multiple second liquid cooling channels. The second liquid cooling channels are connected to the first liquid cooling channels corresponding to the battery cells. Each second liquid cooling channel in the same set of liquid cooling channels is arranged around the central axis of the corresponding first explosion-proof valve. All the second liquid cooling channels in the same set of liquid cooling channels are spaced apart along the radial direction of the first explosion-proof valve.

[0016] As a preferred embodiment of the battery pack, within the same group of liquid cooling channels, along the radial direction of the first explosion-proof valve, the diameter of the second liquid cooling channel farther from the first explosion-proof valve is larger than the diameter of the second liquid cooling channel adjacent to the first explosion-proof valve.

[0017] As a preferred embodiment of the battery pack, the second liquid cooling channel in the liquid cooling channel group that is far from the first explosion-proof valve is a guide channel, and the guide channels of two adjacent liquid cooling channel groups are connected.

[0018] As a preferred embodiment of the battery pack, the bottom of the buffer groove is further provided with at least one outlet.

[0019] The beneficial effects of this utility model are as follows: By setting a first explosion-proof valve on the liquid cooling plate, the second explosion-proof valve of the battery cell is positioned opposite the first explosion-proof valve after the battery cell comes into contact with the liquid cooling plate. This allows the high-temperature and high-pressure thermal runaway gas in the battery cell to break through the second and first explosion-proof valves in the event of thermal runaway. The coolant in the liquid cooling channel can then pass through the first and second explosion-proof valves and enter the battery cell for immersion-type fire extinguishing and cooling, preventing the spread of thermal runaway. During normal use, the liquid cooling plate can continuously exchange heat with the battery cell to prevent the battery cell temperature from becoming too high and reduce the risk of thermal runaway. The buffer groove provides a buffer space between the first and second explosion-proof valves, allowing the thermal runaway gas to explode the second and first explosion-proof valves one by one in a timely manner. This avoids excessive impact force required for the first and second explosion-proof valves to come into contact, which could affect the release of thermal runaway gas and reduce the possibility of battery cell explosion, thus effectively improving the safety of the battery cell and 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 schematic diagram of the battery pack structure according to an embodiment of the present invention;

[0022] Figure 2 This is an exploded view of the battery pack according to an embodiment of the present invention;

[0023] Figure 3 This is a cross-sectional view of the battery pack according to an embodiment of the present utility model;

[0024] Figure 4 yes Figure 3 An enlarged view of point A;

[0025] Figure 5 yes Figure 3 An enlarged view of point B;

[0026] Figure 6 This is a cross-sectional view of the liquid cooling plate according to an embodiment of the present invention.

[0027] In the picture:

[0028] 1. Liquid cooling plate; 11. Liquid cooling channel; 111. First liquid cooling flow channel; 112. Liquid cooling flow channel assembly; 1121. Second liquid cooling flow channel; 12. First side; 13. Buffer tank; 14. First explosion-proof valve; 141. First sealing part; 142. Second sealing part; 15. Positioning groove; 16. First sealing groove; 17. Second sealing groove; 18. Liquid inlet; 19. Liquid outlet; 20. Discharge outlet; 2. Battery cell assembly; 21. Battery cell; 211. Second explosion-proof valve. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0030] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" 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. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0033] like Figure 1 , Figure 2 and Figure 3 As shown, the battery pack of this utility model embodiment includes a liquid cooling plate 1 and a battery cell 21 abutting against the liquid cooling plate 1. The liquid cooling plate 1 is provided with a liquid cooling channel 11 for circulating coolant. The liquid cooling plate 1 has a first side 12 connected to the battery cell 21. A buffer groove 13 is recessed on the first side 12. A first explosion-proof valve 14 connected to the liquid cooling channel 11 is provided at the bottom of the buffer groove 13. The battery cell 21 has a second explosion-proof valve 211. The first explosion-proof valve 14 and the second explosion-proof valve 211 are arranged opposite to each other at a distance.

[0034] It is understandable that by setting a first explosion-proof valve 14 on the liquid cooling plate 1, the second explosion-proof valve 211 of the battery cell 21 and the first explosion-proof valve 14 are spaced apart and opposite each other after the battery cell 21 comes into contact with the liquid cooling plate 1. This allows the high-temperature and high-pressure thermal runaway gas in the battery cell 21 to break through the second explosion-proof valve 211 and the first explosion-proof valve 14, so that the coolant in the liquid cooling channel 11 can pass through the first explosion-proof valve 14 and the second explosion-proof valve 211 and enter the battery cell 21 for immersion fire extinguishing and cooling, preventing the spread of thermal runaway in the battery cell 21. Furthermore, when the battery cell 21 is in normal use, the liquid cooling plate 1 can... The system can continuously exchange heat to cool the battery cell 21, preventing the battery cell 21 from overheating and reducing the risk of thermal runaway. The buffer groove 13 provides a certain gap between the first explosion-proof valve 14 and the second explosion-proof valve 211, so that the thermal runaway gas can explode the second explosion-proof valve 211 and the first explosion-proof valve 14 one by one in a timely manner. This avoids the impact force required for the first explosion-proof valve 14 to come into contact with the second explosion-proof valve 211 being too large, which would affect the release of thermal runaway gas from the battery cell 21, thereby reducing the possibility of battery cell 21 explosion and effectively improving the safety of battery cell 21 and battery pack.

[0035] In one embodiment, such as Figure 3 and Figure 4 As shown, the first explosion-proof valve 14 includes a weak section. The minimum distance between the side of the weak section adjacent to the battery cell 21 and the cavity wall of the liquid cooling channel 11 is D1, and the minimum distance between the bottom of the buffer tank 13 and the cavity wall of the liquid cooling channel 11 is D2, where D1 = (0.6~0.8)D2. That is, the first explosion-proof valve 14 is an integral structure of the liquid cooling plate 1, with only the bottom of the buffer tank 13 being locally weakened. This allows the thermal runaway gas after the second explosion-proof valve 211 explodes to break through the weak section and connect with the liquid cooling channel 11. The first explosion-proof valve 14, constructed with the weak section, has high connection stability with the liquid cooling plate 1, is easy to manufacture, reduces the time for parts production and assembly, and has high production efficiency. For example, D1 = 0.6 times D2, 0.65 times D2, 0.7 times D2, 0.75 times D2, or 0.8 times D2. This proportional relationship between D1 and D2 can effectively control the pressure release characteristics of the weak part, avoid premature or excessive valve opening, ensure that the weak part can respond accurately when the pressure is too high, and enhance the burst stability of the weak part.

[0036] Optionally, such as Figure 3 and Figure 5As shown, the first explosion-proof valve 14 is a thermoplastic seal plug. The bottom of the buffer tank 13 has a connecting hole that communicates with the liquid cooling channel 11, and the thermoplastic seal plug is secured in the connecting hole. The thermal runaway gas of the battery cell 21 has high-temperature characteristics. When the second explosion-proof valve 211 explodes and enters the buffer tank 13, it can thermoplastic seal plug, thereby allowing the connecting hole to connect the liquid cooling channel 11 and the buffer tank 13. This allows coolant to enter the battery cell 21 for immersion-type fire extinguishing and cooling, as well as diluting the electrolyte, inhibiting the chemical reaction of the electrolyte, and controlling the continued occurrence of thermal runaway at its source. Furthermore, as part of the explosion-proof valve, the thermoplastic seal plug can be easily replaced and maintained. It can be directly replaced without disassembling and replacing the entire system, reducing maintenance difficulty and time costs. The thermoplastic seal plug's melting threshold is lower than the temperature of the thermal runaway gas in the battery cell 21.

[0037] Furthermore, such as Figure 5 As shown, the thermoplastic sealing plug includes a first sealing part 141 and a second sealing part 142. The first sealing part 141 is inserted into the connecting hole and abuts against the wall of the connecting hole. Two second sealing parts 142 are spaced apart on the first sealing part 141, and the two second sealing parts 142 abut against the bottom of the buffer groove 13 and the side wall of the liquid cooling channel 11 where the connecting hole is opened, respectively. The two second sealing parts 142 can further enhance the relative positional accuracy between the thermoplastic sealing plug and the connecting hole, and prevent the thermoplastic sealing plug from being inserted into the liquid cooling channel 11 or pushed out by the coolant during insertion, thereby improving the installation stability of the thermoplastic sealing plug and the connecting hole.

[0038] Optionally, the second sealing part 142 is arranged around the central axis of the first sealing part 141, and the two second sealing parts 142 are respectively engaged on both sides of the connecting hole. The first sealing part 141 can effectively seal the connecting hole; the two second sealing parts 142 can increase the contact area between the hot melt sealing plug and the connecting hole and the liquid cooling plate 1 around the connecting hole, ensuring the connection sealing performance of the hot melt sealing plug to the connecting hole.

[0039] Furthermore, such as Figure 2 and Figure 3 As shown, a positioning groove 15 is recessed on the first side 12. One end of the battery cell 21, where the second explosion-proof valve 211 is located, is inserted into the positioning groove 15. A buffer groove 13 is recessed at the bottom of the positioning groove 15. The positioning groove 15 effectively enhances the installation position accuracy of the battery cell 21 and the liquid cooling plate 1, thereby improving the alignment accuracy of the first explosion-proof valve 14 and the second explosion-proof valve 211. Furthermore, the positioning groove 15 restricts at least part of the battery cell 21's periphery, ensuring the installation stability of the battery cell 21 and the liquid cooling plate 1.

[0040] In some embodiments, such as Figure 1 , Figure 2 , Figure 3 and Figure 6 As shown, the battery pack includes multiple cell groups 2 arranged along a first direction (the first direction is the X direction shown in the figure). Each cell group 2 includes multiple cells 21 arranged along a second direction (the second direction is the Y direction shown in the figure). The liquid cooling channel 11 includes a first liquid cooling channel 111. The liquid cooling plate 1 has an inlet 18, an outlet 19, and multiple first liquid cooling channels 111. The inlet 18 and the outlet 19 are respectively located on both sides of the liquid cooling plate 1 along the second direction. All the first liquid cooling channels 111 are spaced apart along the first direction. The length of the first liquid cooling channels 111 extends along the second direction, and the two ends of all the first liquid cooling channels 111 along the second direction are respectively connected to the inlet 18 and the outlet 19. Each cell group 2 is provided with a corresponding first liquid cooling channel 111. Multiple first explosion-proof valves 14 are spaced apart along the second direction on each first liquid cooling channel 111. The first direction is perpendicular to the second direction. By setting multiple cells 21 on a liquid cooling plate 1, the capacity of the battery pack is increased, and multiple first liquid cooling channels 111 are set for cooling. At the same time, cells 21 that are thermally runaway can be targeted to suppress the thermal runaway of cells 21, reduce the impact of local thermal runaway of cells 21 on other cells 21, ensure the overall safety of the battery pack, and reduce the maintenance cost of the battery pack.

[0041] Optionally, such as Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the battery pack also includes a sealing ring. A first sealing groove 16 is recessed around the central axis of the first explosion-proof valve 14 at the bottom of the positioning groove 15 (the central axis of the first explosion-proof valve 14 is the central axis extending along the Z direction, which is perpendicular to both the X and Y directions). The sealing ring is fitted into the first sealing groove 16 and abuts against the battery cell 21. By providing a sealing ring on the first sealing groove 16, the sealing between the bottom of the positioning groove 15 and the side of the battery cell 21 where the first explosion-proof valve 14 is located can be effectively ensured. This allows the thermal runaway gas in the buffer groove 13 to directionally explode the first explosion-proof valve 14, preventing leakage from the gap between the battery cell 21 and the positioning groove 15 that could affect the use of other battery cells 21.

[0042] Optionally, a second sealing groove 17 is recessed around the central axis of the positioning groove 15, and a sealing ring is fitted into the second sealing groove 17, abutting against the outer peripheral wall of the battery cell 21. By providing a sealing ring on the second sealing groove 17, the connection and sealing between the outer peripheral wall of the battery cell 21 and the groove wall of the positioning groove 15 are effectively strengthened, preventing thermal runaway gas from leaking from the gap between the battery cell 21 and the positioning groove 15 and affecting the use of other battery cells 21.

[0043] Furthermore, the contact area between the battery cell 21 and the bottom of the positioning groove 15 is S1, and the area of ​​the end face of the battery cell 21 where the second explosion-proof valve 211 is located is S2. For example, for or The design is moderate, ensuring sufficient contact area for heat exchange between the battery cell 21 and the liquid cooling plate 1 during normal use, while also limiting the size of the buffer tank 13 to prevent thermal runaway gas from directly impacting the liquid cooling plate 1 in the event of thermal runaway explosion of the battery cell 21. This allows the thermal runaway gas that explodes after the second explosion-proof valve 211 to promptly explode the first explosion-proof valve 14. Of course, You can also use Calculate, where Q max ΔT is the maximum heat generation power of cell 21, h is the interface heat transfer coefficient (range 300-6000W / (㎡·K)), ΔT is the maximum allowable temperature difference (preferably 5), and k is the safety factor, range 0.8-1.2.

[0044] In other embodiments, such as Figure 6 As shown, the liquid cooling channel 11 includes a second liquid cooling channel 1121. Each battery cell 21 is provided with a set of liquid cooling channels 112. Each set of liquid cooling channels 112 includes multiple second liquid cooling channels 11. The second liquid cooling channels 1121 are connected to the first liquid cooling channels 111 corresponding to the battery cell 21. Each second liquid cooling channel 1121 in the same set of liquid cooling channels 112 is arranged around the central axis of the corresponding first explosion-proof valve 14, and all the second liquid cooling channels 11 in the same set of liquid cooling channels 112 are spaced apart along the radial direction of the first explosion-proof valve 14 (the radial direction of the first explosion-proof valve 14 is the direction perpendicular to the central axis of the first explosion-proof valve 14). By providing multiple second liquid cooling channels 1121 for each battery cell 21, the effective contact area between the battery cell 21 and the liquid cooling channels is increased, so as to ensure the heat exchange efficiency between each battery cell 21 and the liquid cooling plate 1 and ensure the safety of the battery cell 21 in use.

[0045] Furthermore, within the same group of liquid-cooled flow channels 112, along the radial direction of the first explosion-proof valve 14, the diameter of the second liquid-cooled flow channel 1121 furthest from the first explosion-proof valve 14 is larger than the diameter of the second liquid-cooled flow channel 1121 adjacent to the first explosion-proof valve 14. It is understood that the further away from the first explosion-proof valve 14 the second liquid-cooled flow channel 1121 is, the longer it becomes. Therefore, by increasing the diameter of the second liquid-cooled flow channel 1121 furthest from the first explosion-proof valve 14, the flow rate of the coolant within the second liquid-cooled flow channel 1121 furthest from the first explosion-proof valve 14 is ensured, thereby guaranteeing the cooling effect of each second liquid-cooled flow channel 1121. This improves the uniformity of liquid cooling received by each second liquid-cooled flow channel 1121 from the battery cell 21, reduces the impact of inconsistent cooling temperature differences on the battery cell 21, and extends the service life of the battery cell 21. In addition, besides a circular cross-section, the first explosion-proof valve 14 can also be quadrilateral, pentagonal, or polygonal.

[0046] Optionally, the second liquid cooling channel 1121, located away from the first explosion-proof valve 14 within the liquid cooling channel group 112, serves as a guide channel, and the guide channels of adjacent liquid cooling channel groups 112 are connected. By connecting adjacent guide channels, the flow rate between guide channels is effectively increased, preventing the outermost second liquid cooling channel 1121 within each liquid cooling channel group 112 from having to flow back to the first liquid cooling channel 111 before entering the outermost second liquid cooling channel 1121 of the next liquid cooling channel group 112 each time. This improves the flow linkage between liquid cooling channels and ensures the liquid cooling effect of the liquid cooling plate 1.

[0047] Furthermore, such as Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, at least one outlet 20 is also provided through the bottom of the buffer tank 13. The outlet 20 enables the coolant to be discharged in time after the local cell 21 thermally runs away and explodes, thus preventing the cell 21 or the liquid cooling plate 1 from exploding under high pressure, reducing the impact on adjacent or other cells 21, and improving the service life of the cell 21 and the liquid cooling plate 1.

[0048] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A battery pack, characterized by, The device includes a liquid cooling plate (1) and a battery cell (21) abutting against the liquid cooling plate (1). The liquid cooling plate (1) is provided with a liquid cooling channel (11) for circulating coolant. The liquid cooling plate (1) has a first side surface (12) connected to the battery cell (21). A buffer groove (13) is recessed on the first side surface (12). A first explosion-proof valve (14) connected to the liquid cooling channel (11) is provided at the bottom of the buffer groove (13). The battery cell (21) has a second explosion-proof valve (211). The first explosion-proof valve (14) and the second explosion-proof valve (211) are arranged opposite to each other at a distance.

2. The battery pack of claim 1, wherein, The first explosion-proof valve (14) includes a weak part. The minimum distance between the side of the weak part adjacent to the battery cell (21) and the cavity wall of the liquid cooling channel (11) is D1. The minimum distance between the bottom of the buffer tank (13) and the cavity wall of the liquid cooling channel (11) is D2. D1 = (0.6~0.8)D2.

3. The battery pack of claim 1, wherein, The first explosion-proof valve (14) is a thermoplastic sealing plug. The bottom of the buffer groove (13) is provided with a connecting hole that communicates with the liquid cooling channel (11). The thermoplastic sealing plug is stuck in the connecting hole.

4. The battery pack of claim 3, wherein, The hot-melt sealing plug includes a first sealing part (141) and a second sealing part (142). The first sealing part (141) is inserted into the communicating hole and is abutted against the wall of the communicating hole. Two second sealing parts (142) are spaced apart on the first sealing part (141). The two second sealing parts (142) abut against the bottom of the buffer groove (13) and the side wall of the liquid cooling channel (11) where the communicating hole is opened.

5. The battery pack of any one of claims 1-4, wherein, The first side (12) is recessed and has a positioning groove (15). One end of the battery cell (21) with the second explosion-proof valve (211) is inserted into the positioning groove (15). The buffer groove (13) is recessed at the bottom of the positioning groove (15).

6. The battery pack according to claim 5, characterized in that, The battery pack also includes a sealing ring, and the bottom of the positioning groove (15) is recessed around the central axis of the first explosion-proof valve (14) to form a first sealing groove (16). The sealing ring is engaged in the first sealing groove (16) and abuts against the battery cell (21); and / or, The positioning groove (15) has a second sealing groove (17) recessed around its central axis on its groove wall. The sealing ring is engaged in the second sealing groove (17) and abuts against the outer peripheral wall of the battery cell (21).

7. The battery pack of claim 5, wherein, The contact area of the electric core (21) with the groove bottom of the positioning groove (15) is S1, and the area of the end face of one end of the second explosion-proof valve (211) provided on the electric core (21) is S2, 8. The battery pack of any one of claims 1-4, wherein, The battery pack includes multiple cell groups (2) arranged along a first direction, and each cell group (2) includes multiple cells (21) arranged along a second direction. The liquid cooling channel (11) includes a first liquid cooling channel (111). The liquid cooling plate (1) has an inlet (18), an outlet (19), and multiple first liquid cooling channels (111). The inlet (18) and the outlet (19) are respectively located on both sides of the liquid cooling plate (1) along the second direction. All the first liquid cooling channels (111) The first liquid cooling channels (111) are spaced apart along the first direction, and the length of the first liquid cooling channels (111) extends along the second direction. All the first liquid cooling channels (111) are connected to the liquid inlet (18) and the liquid outlet (19) at both ends along the second direction, respectively. Each group of battery cells (2) is provided with one first liquid cooling channel (111). Multiple first explosion-proof valves (14) are spaced apart along the second direction on each first liquid cooling channel (111). The first direction is perpendicular to the second direction.

9. The battery pack of claim 8, wherein, The liquid cooling channel (11) includes a second liquid cooling channel (1121). Each battery cell (21) is provided with a set of liquid cooling channels (112). Each set of liquid cooling channels (2) includes multiple second liquid cooling channels (1121). The second liquid cooling channels (1121) are connected to the first liquid cooling channels (111) corresponding to the battery cell (21). Each second liquid cooling channel (1121) in the same set of liquid cooling channels (112) is arranged around the central axis of the corresponding first explosion-proof valve (14). All the second liquid cooling channels (1121) in the same set of liquid cooling channels (112) are spaced apart along the radial direction of the first explosion-proof valve (14).

10. The battery pack of claim 9, wherein, Within the same group of liquid cooling channels (112), along the radial direction of the first explosion-proof valve (14), the diameter of the second liquid cooling channel (1121) away from the first explosion-proof valve (14) is larger than the diameter of the second liquid cooling channel (1121) adjacent to the first explosion-proof valve (14).

11. The battery pack of claim 9, wherein, The second liquid cooling channel (1121) in the liquid cooling channel group (112) that is far away from the first explosion-proof valve (14) is a guide channel, and the guide channels of two adjacent liquid cooling channel groups (112) are connected.

12. The battery pack of any one of claims 1-4, wherein, The bottom of the buffer trough (13) is also provided with at least one outlet (20).

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