Battery pack and electric device

Abstract

Disclosed in the present application are a battery pack and an electric device. The battery pack comprises a tray, a battery module, an insulator and a bottom guard plate, wherein the battery module is arranged on the tray and comprises a plurality of battery cells, an explosion-proof valve is provided at the bottom of each battery cell, the tray comprises a bottom plate, the bottom guard plate is fixed to the bottom of the tray, and an exhaust channel is formed between the bottom guard plate and the bottom surface of the tray. By adjusting the relationship between the vertical distance between the pressure relief zone of the explosion-proof valve and the side surface of the bottom of a groove facing the explosion-proof valve, the opening pressure P of the explosion-proof valve, and the area S1 of the pressure relief zone of the explosion-proof valve, the battery pack is made safer.

Description

Battery packs and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 202411046449.1, filed on July 31, 2024, entitled "Battery Pack and Electrical Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery pack and electrical device. Background Technology

[0003] In related technologies, the explosion-proof valve of the battery cell is located at the bottom of the cell, which is mounted on a base plate. The explosion-proof valve of the cell is connected to the vent hole of the base plate, and an insulating component is installed on the base plate at the position corresponding to the vent hole. When some cells experience thermal runaway, the gas can break through the insulating component and enter the venting channel, thus releasing the gas. At the same time, the insulating component can prevent the gas from directly impacting the explosion-proof valve of normal cells that have not experienced thermal runaway, thereby preventing heat diffusion.

[0004] However, in battery packs using related technologies, there is a risk that the insulation components may not be able to be broken through or may only be broken through in a small area when the cells experience thermal runaway. Summary of the Invention

[0005] The purpose of this application is to provide a battery pack and electrical equipment that solves the problem in the related technology that when the battery pack or the battery cell experiences thermal runaway, there is a risk that the insulation component cannot be broken or the broken area is small.

[0006] In a first aspect, this application provides a battery pack, including a tray, a battery pack and an insulating component, wherein the battery pack is disposed on the tray, the battery pack includes a plurality of battery cells, an explosion-proof valve is disposed at the bottom of the battery cells, and the tray includes a base plate;

[0007] The insulating component is recessed in a direction away from the explosion-proof valve of each of the battery cells to form a groove. The base plate is provided with an exhaust hole extending along the thickness direction of the base plate at the position of the explosion-proof valve of each of the battery cells. The insulating component blocks the top opening of the exhaust hole and the groove is located inside the exhaust hole.

[0008] The vertical distance H between the pressure relief zone of the explosion-proof valve and the bottom of the groove facing the side surface of the explosion-proof valve, the opening pressure P of the explosion-proof valve, and the area S1 of the pressure relief zone of the explosion-proof valve satisfy the following:

[0009] 1.4*10 -4 ≤P / (S1*H)≤7.9*10 -4 Where P is in MPa, H is in mm, and S1 is in mm.2 P / (S1*H) is a unitless value.

[0010] In some embodiments, the vertical distance H between the pressure relief zone of the explosion-proof valve and the bottom of the groove facing the side surface of the explosion-proof valve, the opening pressure P of the explosion-proof valve, and the area S1 of the pressure relief zone of the explosion-proof valve satisfy the following:

[0011] 2.2*10 -4 ≤P / (S1*H)≤6*10 -4 .

[0012] In some embodiments, the opening pressure P of the explosion-proof valve ranges from:

[0013] 0.8MPa≤P≤1.25Mpa.

[0014] In some embodiments, the area S1 of the pressure relief zone of the explosion-proof valve ranges from:

[0015] 750mm 2 ≤S1≤1000mm 2 .

[0016] In some embodiments, the vertical distance H between the pressure relief zone of the explosion-proof valve and the bottom of the groove facing one side of the explosion-proof valve ranges as follows:

[0017] 2.1mm≤H≤6.5mm.

[0018] In some embodiments, the area S1 of the pressure relief zone of the explosion-proof valve, the area S2 of the top opening of the vent hole, and the area S3 of the bottom of the groove satisfy the following:

[0019] S1 <S3<S2。

[0020] In some embodiments, 0.3 ≤ S1 / S2 ≤ 0.8;

[0021] And / or,

[0022] 0.3≤S1 / S3≤0.8.

[0023] In some embodiments, the top opening and bottom opening of the vent have the same area, and the projection of the top opening of the vent onto the bottom surface of the base plate coincides with the bottom opening of the vent.

[0024] In some embodiments, the projection of the top opening of the vent hole onto the bottom surface of the base plate is at least partially offset from the bottom opening of the vent hole.

[0025] In some embodiments, the insulating element is disposed between the bottom surface of the battery cell and the base plate, and the groove forms a weak area;

[0026] The wall thickness of the weak area is less than the wall thickness of the other parts of the groove, or the wall surface of the groove is provided with grooves to form the weak area.

[0027] In some embodiments, the bottom wall of the groove has the weak area formed.

[0028] In some embodiments, a flame-retardant sheet is also included, wherein a flame-retardant sheet is attached to the bottom surface of each groove on the side away from the explosion-proof valve.

[0029] In some embodiments, an exhaust channel is formed within the base plate, and the bottom opening of the exhaust hole communicates with the exhaust channel.

[0030] In some embodiments, a bottom guard plate is also included, which is fixed to the bottom of the tray. An exhaust channel is formed between the bottom guard plate and the bottom plate. The exhaust hole penetrates the bottom plate along the thickness direction, and the bottom opening of the exhaust hole communicates with the exhaust channel.

[0031] In some embodiments, the tray further includes a frame surrounding the edge of the base plate, the frame having an exhaust chamber, the frame having a through hole connecting the exhaust chamber and the exhaust channel, and the frame also having an exhaust device that can open for exhaust when the gas pressure in the exhaust chamber is greater than or equal to its opening pressure.

[0032] In some embodiments, the exhaust channel extends along a first direction, the frame includes a first side beam, a second side beam, a third side beam and a fourth side beam, the first side beam and the second side beam are opposite to each other in the first direction, the third side beam and the fourth side beam are opposite to each other in the second direction, and the two ends of the exhaust channel are respectively connected to the exhaust chamber through the through hole;

[0033] The exhaust device is installed on at least one of the first side beam, the second side beam, the third side beam, and the fourth side beam, and the first direction and the second direction intersect.

[0034] In some embodiments, the bottom guard plate is provided with a plurality of protrusions extending in a first direction and arranged in a second direction, the top of the protrusions contacting the bottom plate to divide the exhaust channel into a plurality of sub-exhaust channels, the first direction and the second direction intersecting.

[0035] In some embodiments, the plurality of cells of the battery pack are arranged along a first direction, with a cold plate sandwiched between adjacent cells; or,

[0036] The battery pack has multiple cells arranged in multiple rows along a first direction and multiple columns along a second direction. A cold plate is sandwiched between adjacent cells in the same row, and a heat insulation component is sandwiched between adjacent cells in the same column. The first direction and the second direction intersect.

[0037] In some embodiments, the battery cell is a square battery cell, the first direction is the thickness direction of the battery cell, and the second direction is the length direction of the battery cell.

[0038] In some embodiments, both the positive and negative terminals of the battery cell are disposed on the top of the battery cell.

[0039] In some embodiments, a sealing cap is also included, which is sealed to the top of the tray to form a receiving space between the tray and the tray for receiving the battery pack.

[0040] Secondly, embodiments of this application also provide an electrical device, including the battery pack described above.

[0041] The battery pack provided in this application embodiment, through a reasonable design of the relationship between the vertical distance H between the pressure relief area of ​​the explosion-proof valve and the bottom surface of the groove facing the explosion-proof valve, the opening pressure P of the explosion-proof valve, and the area S1 of the pressure relief area of ​​the explosion-proof valve, can ensure that when a cell in the battery pack experiences thermal runaway, the groove on the insulating component can be completely or mostly broken through. Furthermore, it can shorten the exhaust path of the cell experiencing thermal runaway in the battery pack, increase the exhaust speed of the thermally runaway cell, prevent the thermally runaway cell from catching fire or exploding and affecting surrounding cells, prevent heat diffusion within the battery pack, and prevent thermal runaway of other cells in the battery pack, thereby improving the safety of the battery pack.

[0042] In addition, the explosion-proof valve is located at the bottom of the battery cell, which effectively separates the explosion-proof valve from the high-voltage wiring harness of the battery pack. When the battery pack experiences thermal runaway, the high-temperature gas inside will not damage the high-voltage wiring harness when it is discharged from the explosion-proof valve, which greatly reduces the risk of high-voltage arcing in the battery pack and further improves the safety of the battery pack.

[0043] The electrical equipment provided in this application embodiment has all the advantages of the battery pack described above. Attached Figure Description

[0044] Figure 1 is a schematic diagram of a battery pack provided in some embodiments of this application;

[0045] Figure 2 is a schematic diagram of the tray of the battery pack provided in some embodiments of this application;

[0046] Figure 3 is a schematic diagram of the bottom protective plate of the battery pack provided in some embodiments of this application;

[0047] Figure 4 is a schematic diagram of the insulating component of a battery pack provided in some embodiments of this application;

[0048] Figure 5 is a partial enlarged view of the insulating component of a battery pack provided in some embodiments of this application;

[0049] Figure 6 is a schematic diagram of the sealing cover of the battery pack provided in some embodiments of this application;

[0050] Figure 7 is a schematic diagram of electrical equipment provided in some embodiments of this application.

[0051] Reference numerals: 1. Tray; 11. Base plate; 111. Vent hole; 1111. Top opening; 1112. Bottom opening; 12. Frame; 121. First side beam; 122. Second side beam; 123. Third side beam; 124. Fourth side beam; 125. Vent chamber; 126. Through hole; 127. Vent device; 2. Battery pack; 21. Cell; 211. Explosion-proof valve; 212. Positive terminal; 213. Negative terminal; 3. Insulating component; 31. Weak area; 4. Bottom protective plate; 41. Raised strip; 5. Vent channel; 6. Flame retardant sheet; 7. Heat insulation component; 8. Fireproof plate; 9. Sealing cover; 10. Battery pack; 20. Electrical equipment. Detailed Implementation

[0052] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0053] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, 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.

[0054] Referring to Figures 1 to 5, some embodiments of the present application provide a battery pack including a tray 1, a battery pack 2, and an insulating member 3. The battery pack 2 is disposed on the tray 1 and includes a plurality of battery cells 21. An explosion-proof valve 211 is disposed at the bottom of each battery cell 21. The tray 1 includes a base plate 11. The insulating member 3 is recessed in a direction away from the explosion-proof valve 211 of each battery cell 21 to form a groove 31. An exhaust hole 111 extending along the thickness direction of the base plate 11 is disposed on the base plate 11 at the position of the explosion-proof valve 211 of each battery cell 21. The insulating member 3 blocks the top opening 1111 of the exhaust hole 111, and the groove 31 is located within the exhaust hole 111. The vertical distance H between the pressure relief zone of the explosion-proof valve 211 and the bottom surface of the groove 31 facing the explosion-proof valve 211, the opening pressure P of the explosion-proof valve 211, and the area S1 of the pressure relief zone of the explosion-proof valve 211 satisfy the following:

[0055] 1.4*10 -4 ≤P / (S1*H)≤7.9*10 -4 Where P is in MPa, H is in mm, and S1 is in mm. 2 P / (S1*H) is a unitless value.

[0056] Among them, the area S1 of the pressure relief zone is the gas passage area when the explosion-proof valve 211 is opened, which can be obtained by measurement and calculation.

[0057] The opening pressure P of the explosion-proof valve 211 can be obtained through testing. Specifically, the liquid injection port cover of the battery cell 21 is opened, and a vent pipe is connected. The part of the vent pipe that contacts the battery cell 21 is sealed with sealant. The battery cell 21 is placed into the explosion-proof container using a clamp. The vent pipe and a pressure testing device are connected, and the opening pressure of the explosion-proof valve 21 is tested under a specific pressure. The above operation is repeated to obtain the average value of the opening pressure P of the explosion-proof valve 211.

[0058] The gas pressure can be estimated by the opening pressure P of the explosion-proof valve 211. When the opening pressure P of the explosion-proof valve 211 is within a certain range, by reasonably adjusting the opening area of ​​the explosion-proof valve 211 (i.e., the area S1 of the pressure relief zone) and the distance of the gas breaking through the groove 31 (the vertical distance H between the pressure relief zone of the explosion-proof valve 211 and the bottom of the groove 31 facing the side surface of the explosion-proof valve 211), most of the discharged gas completely or mostly breaks through the groove 31 of the insulating component 3, smoothly enters the exhaust channel 5, and is discharged outside the battery pack through the exhaust channel 5, so as not to affect other cells 21 and avoid thermal runaway of other cells 21.

[0059] According to the battery pack of this application embodiment, by rationally designing the relationship between the vertical distance H between the pressure relief area of ​​the explosion-proof valve 211 and the bottom surface of the groove 31 facing the explosion-proof valve 211, the opening pressure P of the explosion-proof valve 211, and the area S1 of the pressure relief area of ​​the explosion-proof valve 211, it can be ensured that when a certain cell 21 in the battery pack experiences thermal runaway, the groove 31 at the corresponding position on the insulating member 3 can be completely or mostly broken through. In addition, it can shorten the exhaust path of the cell 21 that has experienced thermal runaway in the battery pack, increase the exhaust speed of the cell 21 that has experienced thermal runaway, avoid the cell 21 that has experienced thermal runaway from catching fire or exploding and affecting the surrounding cells 21, prevent heat diffusion in the battery pack, and prevent other cells 21 in the battery pack from experiencing thermal runaway, thereby improving the safety of the battery pack.

[0060] In addition, the explosion-proof valve 211 is located at the bottom of the battery cell 21, which effectively separates the explosion-proof valve 211 from the high-voltage wiring harness of the battery pack. When the battery pack experiences thermal runaway, the high-temperature gas inside will not damage the high-voltage wiring harness when it is discharged from the explosion-proof valve 211, which greatly reduces the risk of high-voltage arcing in the battery pack and further improves the safety of the battery pack.

[0061] In some embodiments, a bottom guard plate 4 is also included, which is fixed to the bottom of the tray 1. An exhaust channel 5 is formed between the bottom guard plate 4 and the bottom plate 11. An exhaust hole 111 penetrates the bottom plate 11 along the thickness direction of the bottom plate 11, and the bottom opening 1112 of the exhaust hole 111 communicates with the exhaust channel 5.

[0062] Pallet 1 is made of aluminum sheet, which has the advantages of being lightweight and strong. Specifically, pallet 1 adopts a double-layer aluminum sheet structure, further reducing its weight.

[0063] The insulating component 3 is located at the bottom of the cell 21. This prevents gas from entering the exhaust channel 5 and directly impacting the explosion-proof valve of the normal cell that has not experienced thermal runaway, thus preventing thermal diffusion. At the same time, it effectively avoids the risk of liquid conduction caused by the electrolyte of the cell 21 leaking onto the bottom plate 11 of the tray 1.

[0064] The battery cell 21 is fixed to the insulating component 3 with structural adhesive. The structural adhesive is applied to both sides of the explosion-proof valve 211 of the battery cell 21.

[0065] Referring to Figure 1, a fireproof board 8 is also provided on the bottom protective plate 4, and the fireproof board 8 is located at the bottom of the exhaust channel 5. The fireproof board 8 can prevent the high-temperature and high-pressure gas from melting the bottom protective plate 4. The fireproof board 8 can be a mica board.

[0066] In some other embodiments not shown in the figure, an exhaust channel 5 is formed in the base plate 11, and the bottom opening 1112 of the exhaust hole 111 is connected to the exhaust channel 5.

[0067] In some embodiments, the vertical distance H between the pressure relief zone of the explosion-proof valve 211 and the bottom surface of the groove 31 facing the explosion-proof valve 211, the opening pressure P of the explosion-proof valve 211, and the area S1 of the pressure relief zone of the explosion-proof valve 211 satisfy the following:

[0068] 2.2*10 -4 ≤P / (S1*H)≤6*10 -4 .

[0069] In some embodiments, the opening pressure P of the explosion-proof valve 211 ranges from:

[0070] 0.8MPa≤P≤1.25Mpa.

[0071] In some embodiments, the area S1 of the pressure relief zone of the explosion-proof valve 211 ranges from:

[0072] 750mm 2 ≤S1≤1000mm 2 .

[0073] In some embodiments, the vertical distance H between the pressure relief zone of the explosion-proof valve 211 and the bottom surface of the groove 31 facing the explosion-proof valve 211 ranges as follows:

[0074] 2.1mm≤H≤6.5mm.

[0075] For example, when P is 1.24 MPa and S1 is 854 mm. 2 When H is 6.4mm, P / (S1*H) is 0.000238608. At this time, when the simulated thermal runaway cell 21 experiences thermal runaway, the explosion-proof valve 211 is fully opened, the groove 31 is completely ruptured, the thermal runaway cell 21 exhausts gas normally, the thermal runaway cell 21 does not catch fire or explode, there is no thermal diffusion within the battery pack, and the other cells 21 in the battery pack do not experience thermal runaway.

[0076] For example, when P is 1.24 MPa and S1 is 926 mm... 2 When H is 2.4mm, P / (S1*H) is 0.000557955. At this time, when the simulated thermal runaway cell 21 experiences thermal runaway, the explosion-proof valve 211 is fully opened, the groove 31 is completely ruptured, the thermal runaway cell 21 exhausts gas normally, the thermal runaway cell 21 does not catch fire or explode, there is no thermal diffusion within the battery pack, and the other cells 21 in the battery pack do not experience thermal runaway.

[0077] For example, when P is 0.86 MPa and S1 is 854 mm... 2When H is 6.3mm, P / (S1*H) is 0.000159845. At this time, when the simulated thermal runaway cell 21 experiences thermal runaway, the explosion-proof valve 211 is fully opened, most of the groove 31 is broken, no gas rebound occurs, the thermal runaway cell 21 does not catch fire or explode, no thermal diffusion occurs within the battery pack, most of the gas generated by the thermal runaway cell 21 is discharged from the exhaust channel 5, and the other cells 21 in the battery pack do not experience thermal runaway.

[0078] In some embodiments, the area S1 of the pressure relief zone of the explosion-proof valve 211, the area S2 of the top opening 1111 of the vent 111, and the area S3 of the bottom of the groove 31 satisfy the following:

[0079] S1 <S3<S2。

[0080] When cell 21 experiences thermal runaway, the emitted material breaks through the groove 31 on the insulating component 3 and enters the exhaust channel 5, from which the gas is then discharged outside the battery pack. Since the explosion-proof valve 211 of cell 21 does not diffuse along a straight line during exhaust, but rather diffuses to varying degrees in different directions, to prevent impact on other cells 21, the area S2 of the top opening 1111 of the exhaust port 111 and the area S3 of the bottom of the groove 31 need to be larger than the pressure relief area S1 of the explosion-proof valve 21. The area S3 of the bottom of the groove 31 can be the area of ​​the side surface of the bottom wall of the groove 31 facing the explosion-proof valve 211. Since the groove 31 is located in the exhaust port 111, the area S3 of the bottom of the groove 31 is also smaller than the area S2 of the top opening 1111 of the exhaust port 111.

[0081] In addition, the area S3 at the bottom of the groove 31 is larger than the pressure relief area S1 of the explosion-proof valve 21. In this way, the gas discharged by the explosion-proof valve 211 basically impacts the bottom of the groove 31, which can further avoid the risk that the groove 31 cannot be broken.

[0082] If the area of ​​the exhaust port 111 is too small, it cannot be guaranteed that most of the gas will enter the exhaust port 111. If the gas pressure is too low, the groove 31 cannot be opened, and the gas cannot enter the exhaust channel 5, affecting other cells 21 and causing a short circuit. When the area of ​​the groove 31 is too large, it cannot be guaranteed that the groove 31 will be completely opened. If the groove 31 is not completely broken, the gas will rebound into the cell 21, causing thermal runaway.

[0083] In some embodiments, 0.3 ≤ S1 / S2 ≤ 0.8. In this embodiment, by setting 0.3 ≤ S1 / S2 ≤ 0.8, the area of ​​the top opening 1111 of the exhaust port 111 is reduced while ensuring the pressure relief effect of the explosion-proof valve 211, thereby improving space utilization.

[0084] In some embodiments, 0.3 ≤ S1 / S3 ≤ 0.8. In this embodiment, by setting 0.3 ≤ S1 / S2 ≤ 0.8, the area of ​​the bottom of the groove 31 is reduced while ensuring the pressure relief effect of the explosion-proof valve 211, so as to facilitate the forming of the insulating part 3 and improve space utilization.

[0085] In some embodiments, the insulating member 3 is disposed between the bottom surface of the battery cell 21 and the top surface of the base plate 11.

[0086] However, in some other embodiments not shown in the figures, the insulating element 3 may also be embedded in the base plate 11.

[0087] In some embodiments, the groove 31 has a weak area, the wall thickness of which is less than the wall thickness of other parts of the groove 31.

[0088] However, in some other embodiments not shown in the figures, the weak area can also be constructed such that the wall of the groove 31 is provided with grooves to form the weak area.

[0089] In some embodiments, the bottom wall of the groove 31 has the weak area. In this way, the gas discharged by the explosion-proof valve 211 will basically impact the weak area of ​​the groove 31, which can further avoid the risk that the groove 31 cannot be broken through and improve the pressure relief effect of the explosion-proof valve 211.

[0090] In some embodiments, the top opening 1111 and the bottom opening 1112 of the vent 111 have the same area, and the projection of the top opening 1111 of the vent 111 onto the bottom surface of the base plate 11 coincides with the bottom opening 1112 of the vent. That is, the top opening 1111 and the bottom opening 1112 have the same shape and are directly opposite each other. This shortens the venting path.

[0091] However, in some other embodiments not shown in the figures, the projection of the top opening 1111 of the vent 111 onto the bottom surface of the base plate 11 is at least partially offset from the bottom opening 1112 of the vent 111. This prevents the gas emitted by the explosion-proof valve 211 from directly impacting the bottom wall of the exhaust channel 5 and causing a rebound, which could lead to thermal runaway of other normal battery cells 21.

[0092] In some embodiments, referring to Figures 1 and 5, a flame-retardant sheet 6 is also included, with a flame-retardant sheet 6 attached to the bottom surface of each groove 31 on the side away from the explosion-proof valve 211. The insulating component 3 is typically made of plastic. When gas breaks through the groove 31, the high gas temperature can easily cause combustion at the location of the groove 31. The flame-retardant sheet 6 can prevent the spread of combustion. At the same time, the flame-retardant sheet 6 of the normal battery cell 21 can also prevent its insulating component 3 from directly burning under the influence of the high-temperature gas emitted from the explosion-proof valve 211 of the thermal runaway battery cell 21, thus preventing the normal battery cell 21 from thermal runaway. The shape of the flame-retardant sheet 6 matches the shape of the bottom wall of the groove 31 to better play its flame-retardant role. The flame-retardant sheet 6 can be made of mica.

[0093] In some embodiments, referring to FIG2, the tray 1 further includes a frame 12 disposed around the edge of the base plate 11. The frame 12 is provided with an exhaust chamber and a through hole connecting the exhaust chamber and the exhaust channel 5. The frame 12 is also provided with an exhaust device, which can open to exhaust gas generated by thermal runaway of the battery pack when the gas pressure in the exhaust chamber is greater than or equal to its opening pressure, so as to discharge the gas generated by thermal runaway of the battery pack to the outside of the battery pack. The exhaust device is an exhaust valve or an explosion-proof valve. The exhaust valve can be, for example, a one-way valve. The explosion-proof valve can be, for example, a notched or weakened area.

[0094] In some embodiments, referring to Figures 2 and 3, the exhaust channel 5 extends along a first direction, and the frame 12 includes a first side beam 121, a second side beam 122, a third side beam 123, and a fourth side beam 124. The first side beam 121 and the second side beam 122 are opposite to each other in the first direction, and the third side beam 123 and the fourth side beam 124 are opposite to each other in the second direction. The two ends of the exhaust channel 5 are respectively connected to the exhaust chamber through the through hole. The exhaust device is disposed on at least one of the first side beam 121, the second side beam 122, the third side beam 123, and the fourth side beam 124. The first direction and the second direction intersect.

[0095] In some embodiments, referring to FIG3, the bottom guard plate 4 is provided with a plurality of protrusions 41 extending in a first direction and arranged in a second direction. The top of the protrusions 41 contacts the bottom plate 11 to divide the exhaust channel 5 into a plurality of sub-exhaust channels. The first direction and the second direction intersect. The bottom guard plate 4 is recessed downward, and the edge of the bottom guard plate 4 is fixed to the bottom of the tray 1 by bolts. The height of the protrusions 41 is less than the height of the edge of the bottom guard plate 4.

[0096] In some embodiments, the plurality of battery cells 21 of the battery pack 2 are arranged along a first direction, and a cold plate is sandwiched between adjacent battery cells 21. That is, the battery pack 2 is provided in a row.

[0097] In other embodiments, the battery cells 21 of the battery pack 2 are arranged in multiple rows along a first direction and in multiple columns along a second direction. A cold plate is sandwiched between adjacent cells 21 in the same row, and a heat insulation component 7 (see Figure 1) is sandwiched between adjacent cells 21 in the same column. The heat insulation component 7 can be made of aerogel or hydrogel, and this design is not limited thereto. The heat insulation component 7 is used for insulation, heat insulation, and fire prevention between adjacent cells 21 to prevent heat from thermally runaway cells 21 from being conducted to normal cells 21 and to prevent the spread of thermal runaway.

[0098] In some embodiments, the battery cell 21 is a square battery cell, the first direction is the thickness direction of the battery cell 21, and the second direction is the length direction of the battery cell 21.

[0099] In some embodiments, an explosion-proof valve 211 is provided at the bottom of the battery cell 21, and the positive terminal 212 and negative terminal 213 of the battery cell 21 are both provided at the top of the battery cell 21. Therefore, electrical isolation of the battery cell 21 can be achieved, improving the safety performance of the battery pack.

[0100] In some embodiments, referring to FIG6, a sealing cap 9 is also included, which is sealed to the top of the tray 1 to form a receiving space therebetween for receiving the battery pack 2.

[0101] Of course, in some other embodiments, the sealing cover 9 can be omitted, and the vehicle floor can be used as the sealing cover 9 instead. That is, the tray 1 is attached to the lower surface of the floor.

[0102] The battery pack described in the above embodiment operates on the following principle:

[0103] When a certain cell 21 experiences thermal runaway, the gas breaks through the explosion-proof valve 211 at the bottom of the cell 21 and the groove 31, and enters the exhaust channel 5 through the exhaust hole 111. Then, it enters the exhaust chamber inside the frame 12 through the through hole on the frame 12 of the tray 1. When the gas pressure in the exhaust chamber is greater than or equal to the opening pressure of the exhaust device, the gas in the exhaust chamber is discharged to the outside of the battery pack through the exhaust device.

[0104] Table 1 below shows the experimental data for 26 specific embodiments of this application. It can be seen that the vertical distance H between the pressure relief area of ​​the explosion-proof valve 211 and the bottom surface of the groove 31 facing the explosion-proof valve 211, the opening pressure P of the explosion-proof valve 211, and the area S1 of the pressure relief area of ​​the explosion-proof valve 211 satisfy 1.4*10 -4 ≤P / (S1*H)≤7.9*10 -4When the simulated thermal runaway cell 21 experiences thermal runaway, the gas can be rapidly discharged from the battery pack. The thermally runaway cell 21 does not ignite or explode, and there is no thermal diffusion within the battery pack. Other cells 21 in the battery pack do not experience thermal runaway. Furthermore, in all 26 specific embodiments, the explosion-proof valve 211 opens (breaks through). The groove 31 is completely broken through in most embodiments, and mostly broken through in a few embodiments. The groove 31 is always able to be broken through, without affecting or only slightly affecting the venting of the simulated thermal runaway cell 21. In most embodiments, the simulated thermal runaway cell 21 can vent gas normally (completely venting), and in a few embodiments, the simulated thermal runaway cell 21 can vent most of the gas.

[0105] Table 1

[0106] Table 2 below shows the experimental data for 14 comparative examples, which have the same battery pack structure as the embodiments. It can be seen that the vertical distance H between the pressure relief area of ​​the explosion-proof valve 211 and the bottom surface of the groove 31 facing the explosion-proof valve 211, the opening pressure P of the explosion-proof valve 211, and the area S1 of the pressure relief area of ​​the explosion-proof valve 211 do not satisfy 1.4*10 -4 ≤P / (S1*H)≤7.9*10 -4 When the simulated thermal runaway cell 21 experiences thermal runaway, the area of ​​the groove 31 that is broken open is small or not broken, resulting in thermal diffusion within the battery pack. The thermal runaway cell 21 causes other cells 21 in the battery pack to experience thermal runaway.

[0107] Table 2

[0108] Furthermore, referring to Figure 7, this application embodiment also provides an electrical device 20, including the battery pack 10 described above.

[0109] The electrical device 20 provided in this application embodiment has all the advantages of the battery pack 10 in the above embodiments.

[0110] Electrical equipment 20 can be vehicles, energy storage equipment, aircraft, ships, etc.

[0111] In the description of this specification, the references to the terms "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0112] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery pack (10) characterized by, The application relates to a battery pack, which comprises a tray (1), a battery pack (2) and an insulating piece (3), wherein the battery pack (2) is arranged on the tray (1), the battery pack (2) comprises a plurality of battery cells (21), the bottom of each battery cell (21) is provided with an explosion-proof valve (211), and the tray (1) comprises a bottom plate (11). The insulating piece (3) is recessed to form a groove (31) in a direction away from the explosion-proof valve (211) at a position corresponding to the explosion-proof valve (211) of each battery cell (21), the bottom plate (11) is provided with an exhaust hole (111) extending along the thickness direction of the bottom plate (11) at a position corresponding to the explosion-proof valve (211) of each battery cell (21), the insulating piece (3) blocks the top opening (1111) of the exhaust hole (111), and the groove (31) is located in the exhaust hole (111). The vertical distance H between the relief area of the explosion-proof valve (211) and the bottom of the groove (31) towards the side surface of the explosion-proof valve (211), the opening pressure P of the explosion-proof valve (211) and the area S1 of the relief area of the explosion-proof valve (211) satisfy the following conditions: 2.1mm<=H<=6.5mm. 1.4*10 -4 ≤ P / (S1*H) ≤ 7.9*10 -4 ; wherein P has the unit MPa, H has the unit mm, S1 has the unit mm 2 and P / (S1*H) is a number without unit.

2. The battery pack (10) according to claim 1, characterized in that The vertical distance H from the relief area of the explosion-proof valve (211) to the side surface of the bottom of the groove (31) facing the explosion-proof valve (211), the opening pressure P of the explosion-proof valve (211), and the area S1 of the relief area of the explosion-proof valve (211) satisfy: 2.2*10 -4 ≤P / (S1*H)≤6*10 -4 .

3. The battery pack (10) according to claim 1 or 2, characterized in that The opening pressure P of the explosion-proof valve (211) is in the range of 0.8MPa<=P<=1.25Mpa.

4. The battery pack (10) according to any one of claims 1-3, characterized in that, The area S1 of the pressure relief zone of the explosion-proof valve (211) is in the range of 750mm 2 ≤ S1 ≤ 1000mm 2 .

5. The battery pack (10) according to any one of claims 1-4, characterized in that, The vertical distance H between the relief area of the explosion-proof valve (211) and the bottom of the groove (31) towards the side surface of the explosion-proof valve (211) is in the range of 2.1mm<=H<=6.5mm.

6. The battery pack (10) according to any one of claims 1-5, characterized in that, The area S1 of the relief area of the explosion-proof valve (211), the area S2 of the top opening (1111) of the exhaust hole (111) and the area S3 of the bottom of the groove (31) satisfy the following conditions: S1<S3<S2.

7. The battery pack (10) according to claim 6, characterized in that 0.3<=S1 / S2<=0.8; And / or, 0.3<=S1 / S3<=0.

8.

8. The battery pack (10) according to any one of claims 1-7, characterized by, The top opening (1111) and the bottom opening (1112) of the exhaust hole (111) have the same area, and the projection of the top opening (1111) of the exhaust hole (111) on the bottom surface of the bottom plate (11) coincides with the bottom opening (1112) of the exhaust hole (111).

9. The battery pack (10) according to any one of claims 1-7, characterized by, The projection of the top opening (1111) of the exhaust hole (111) on the bottom surface of the bottom plate (11) is at least partially staggered with the bottom opening (1112) of the exhaust hole (111).

10. The battery pack (10) according to any one of claims 1-9, characterized in that, The insulating piece (3) is arranged between the bottom surface of the battery cell (21) and the bottom plate (11), and the groove (31) is formed with a weak area (31). The weak area (31) has a wall thickness smaller than that of other parts of the groove (31), or the wall surface of the groove (31) is provided with a notch to form the weak area (31).

11. The battery pack (10) according to claim 10, characterized in that The bottom wall of the groove (31) is formed with the weak area (31).

12. The battery pack (10) according to any one of claims 1-11, characterized in that The bottom of each groove (31) is attached with a fire-retardant sheet (6) away from the side surface of the explosion-proof valve (211).

13. The battery pack (10) according to any one of claims 1-12, characterized in that, The bottom plate (11) is formed with an exhaust passage (5), and the bottom opening (1112) of the exhaust hole (111) communicates with the exhaust passage (5).

14. The battery pack (10) according to any one of claims 1-12, characterized by Further comprising a bottom guard plate (4) fixed at the bottom of the tray (1), an exhaust passage (5) is formed between the bottom guard plate (4) and the bottom plate (11), the exhaust hole (111) penetrates the bottom plate (11) along the thickness direction of the bottom plate (11), and the bottom opening (1112) of the exhaust hole (111) communicates with the exhaust passage (5).

15. The battery pack (10) according to claim 13 or 14, characterized in that The tray (1) further comprises a frame (12) arranged around the edge of the bottom plate (11), the frame (12) is provided with an exhaust cavity (125), the frame (12) is provided with a through hole (126) communicating the exhaust cavity (125) and the exhaust passage (5), and the frame (12) is further provided with an exhaust device (127) capable of opening exhaust when the gas pressure in the exhaust cavity (125) is greater than or equal to its opening pressure.

16. The battery pack (10) according to claim 15, characterized by The exhaust passage (5) extends in a first direction, the frame (12) comprises a first edge beam (121), a second edge beam (122), a third edge beam (123) and a fourth edge beam (124), the first edge beam (121) and the second edge beam (122) are opposite in the first direction, the third edge beam (123) and the fourth edge beam (124) are opposite in a second direction, and the two ends of the exhaust passage (5) respectively communicate with the exhaust cavity (125) through the through hole (126); The exhaust device (127) is arranged on at least one of the first edge beam (121), the second edge beam (122), the third edge beam (123) and the fourth edge beam (124), and the first direction and the second direction intersect.

17. The battery pack (10) according to any one of claims 14-16, characterized by The bottom guard plate (4) is provided with a plurality of convex strips (41) extending in a first direction and arranged in a second direction, the top of the convex strip (41) is in contact with the bottom plate (11) to separate the exhaust passage (5) into a plurality of sub-exhaust passages, and the first direction and the second direction intersect.

18. The battery pack (10) according to any one of claims 1-17, characterized by The plurality of battery cells (21) of the battery pack (2) are arranged in a first direction, and a cold plate is arranged between adjacent battery cells (21); or, The plurality of battery cells (21) of the battery pack (2) are arranged in a plurality of rows in a first direction and a plurality of columns in a second direction, a cold plate is arranged between adjacent battery cells (21) in the same row, and a heat insulation member (7) is arranged between adjacent battery cells (21) in the same column, and the first direction and the second direction intersect.

19. The battery pack (10) according to claim 18, characterized by The battery cell (21) is a square battery cell (21), the first direction is the thickness direction of the battery cell (21), and the second direction is the length direction of the battery cell (21).

20. The battery pack (10) according to any one of claims 1-9, characterized by The positive pole column (212) and the negative pole column (213) of the battery cell (21) are arranged on the top of the battery cell (21).

21. The battery pack (10) according to any one of claims 1-9, characterized by The battery pack (10) further comprises a sealing cover (9) sealingly connected to the top of the tray (1) to form a containing space for containing the battery pack (2) therebetween.

22. An electrical device (20) characterized by: The battery pack (10) comprises the battery pack (10) according to any one of claims 1-21.

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