Battery pack

Abstract

The utility model relates to the technical field of new energy batteries, and discloses a battery pack which is characterized in that a hollow cavity is formed in a side beam, and the hollow cavity extends along the length direction of the side beam to form a channel; the boundary beam further comprises a separation structure, the separation structure comprises a first elastic film, the first elastic film is arranged in the boundary beam in the direction transverse to the length direction of the boundary beam so as to separate the hollow cavity into a negative pressure cavity and a normal pressure cavity, a first through hole is formed in the boundary beam, and the first through hole communicates with the negative pressure cavity and the installation space; the second elastic film covers the first through hole so as to separate the negative pressure cavity from the mounting space; the pressure in the negative pressure cavity is preset to be lower than the atmospheric pressure. According to the utility model, when air is exhausted to the mounting space after thermal runaway of the battery core, exhausted high-temperature jet flows break through part of the second elastic film and are sucked into the negative pressure cavity, and the space of the negative pressure cavity can play roles in buffering, cooling and pressure drop, so that the heat spreading rate in the battery pack is slowed down, and the overall safety of the battery pack is improved.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, specifically to battery packs. Background Technology

[0002] With the continuous development of new energy technologies, more and more new energy vehicles are appearing in people's lives. As the power source for new energy vehicles, the safety of the battery pack is particularly important. Thermal runaway is one of the most common safety hazards associated with battery packs.

[0003] However, in related technologies, the rapid heat spread rate inside the battery pack reduces the time for emergency response and escape from the vehicle, and poses a significant threat to the personal safety of passengers, resulting in low overall safety of the battery pack. Utility Model Content

[0004] In view of this, the present invention provides a battery pack to solve the problems of rapid heat spread rate inside the battery pack and low overall safety of the battery pack.

[0005] In a first aspect, this utility model provides a battery pack, comprising: a side beam enclosing an installation space suitable for installing battery cells; a hollow cavity formed inside the side beam, the hollow cavity extending along the length of the side beam to form a channel; the side beam further comprising a partition structure, the partition structure comprising a first elastic membrane, the first elastic membrane being transverse to the length of the side beam and disposed within the side beam to partition the hollow cavity into a negative pressure chamber and a normal pressure chamber; a first through hole being provided on the side of the side beam, the first through hole being suitable for connecting the negative pressure chamber and the installation space, the first through hole being suitable for corresponding to a battery cell venting structure; and a second elastic membrane covering the first through hole to isolate the negative pressure chamber from the installation space; wherein the pressure inside the negative pressure chamber is preset to be lower than atmospheric pressure.

[0006] Beneficial effects: When the battery cell experiences thermal runaway and vents to the installation space, the high-temperature jet breaks through the melted second elastic membrane and is drawn into the negative pressure chamber. The space of the negative pressure chamber can buffer, cool, and reduce pressure, thereby slowing down the rate of heat spread inside the battery pack, providing more time for passengers to handle emergencies and escape from the vehicle, and improving the overall safety of the battery pack.

[0007] In one alternative embodiment, the system further includes a first explosion-proof valve, which connects the atmospheric pressure chamber to the external environment.

[0008] In one optional embodiment, the breakdown pressure differential of the second elastic membrane is higher than that of the first elastic membrane; and / or, the breakdown pressure differential of the second elastic membrane is higher than the opening pressure of the first explosion-proof valve.

[0009] Beneficial effects: The pressure difference of the second elastic membrane is higher than that of the first elastic membrane and the opening pressure of the first explosion-proof valve. After the pressure in the negative pressure chamber increases, the first elastic membrane is guaranteed to be destroyed first, preventing the gas from breaking through the intact part of the second elastic membrane and causing backflow, thus avoiding the impact of high-temperature gas on the uncontrolled battery cells.

[0010] In one optional embodiment, the opening pressure of the first explosion-proof valve is 5 kPa ± 1 kPa, the rupture pressure difference of the first elastic membrane is 3 kPa ± 1 kPa, and the rupture pressure difference of the second elastic membrane is 12 kPa ± 1 kPa.

[0011] In one optional embodiment, the side beam includes a first side beam, a second side beam, and a third side beam. Two first side beams are spaced apart along a first direction, and the second and third side beams are spaced apart along a second direction. The first and second directions intersect. The two ends of the first side beam are connected to the second and third side beams respectively to enclose and form the installation space. A negative pressure cavity is formed inside the first side beam. The first through hole is opened on the side of the first side beam facing the installation space. At least one of the partition structures is provided inside the first side beam so that at least one end of the negative pressure cavity is adapted to communicate with the normal pressure cavity.

[0012] In one optional embodiment, the partition structure further includes an insert plate disposed within the first side beam. The insert plate has a second through hole adapted to connect the negative pressure chamber and the normal pressure chamber. The first elastic membrane is disposed on the insert plate and covers the second through hole.

[0013] In an optional embodiment, the battery pack further includes: a longitudinal beam extending along a second direction within the mounting space, the longitudinal beam being connected to a second side beam, the interior of the longitudinal beam communicating with the interior of the second side beam and forming the negative pressure chamber therein, a third through hole being provided on the side of the longitudinal beam, the third through hole being adapted to connect the negative pressure chamber and the mounting space, the third through hole being adapted to correspond to the cell venting structure, a second elastic membrane covering the third through hole to isolate the negative pressure chamber from the mounting space, and at least one of the partition structures being provided in the second side beam so that at least one end of the negative pressure chamber forms the normal pressure chamber.

[0014] Beneficial effects: By forming a negative pressure cavity within the connected longitudinal beam and the second side beam, more space is provided to buffer, cool, and reduce pressure, further slowing down the rate of increase in internal air pressure and temperature of the battery pack, and delaying the rate of thermal spread of the entire battery pack.

[0015] In one optional embodiment, the battery pack further includes: a battery cell disposed within the mounting space; a top cover assembly disposed on top of the side beam and connected to the side beam along the thickness direction of the battery pack; and a bottom plate disposed at the bottom of the side beam and connected to the side beam along the thickness direction of the battery pack.

[0016] In one alternative embodiment, a plurality of battery cells are provided, and the plurality of battery cells are arranged in a plurality of rows along a first direction.

[0017] In one optional embodiment, the battery pack further includes a heat insulation structure, and a plurality of battery cells are arranged along a second direction, with the heat insulation structure disposed between two adjacent battery cells along the second direction.

[0018] Beneficial effects: By setting up a heat insulation structure, heat is blocked from being transferred between two adjacent cells, preventing heat diffusion and thus slowing down the rate of thermal runaway. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a top view of the battery pack according to an embodiment of the present invention (the top cover assembly is not shown).

[0021] Figure 2 This is a schematic diagram of the connection structure between the side beam and the longitudinal beam in an embodiment of this utility model;

[0022] Figure 3 This is a structural schematic diagram of the first side beam at one angle according to an embodiment of the present utility model;

[0023] Figure 4 This is a structural schematic diagram of the first side beam from another angle in an embodiment of this utility model;

[0024] Figure 5 This is a schematic diagram of the connection structure between the second side beam and the longitudinal beam in an embodiment of this utility model;

[0025] Figure 6 This is a schematic diagram of the partition structure according to an embodiment of the present utility model;

[0026] Figure 7This is a schematic diagram of the cross-sectional structure of the battery pack in an embodiment of the present invention, perpendicular to the thickness direction (the cell exhaust structure faces the first side beam and the longitudinal beam);

[0027] Figure 8 This is a schematic diagram of the cross-sectional structure of the battery pack in an embodiment of the present invention, perpendicular to the thickness direction (the cell exhaust structure faces only the first side beam);

[0028] Figure 9 for Figure 2 Enlarged diagram of point A in the diagram.

[0029] Explanation of reference numerals in the attached figures:

[0030] 10. Side beam; 11. First side beam; 111. First slot; 112. Air extraction hole; 113. Third slot; 12. Second side beam; 121. Second slot; 13. Third side beam; 14. First through hole; 20. Separation structure; 21. First elastic membrane; 22. Insert plate; 30. Second elastic membrane; 41. First explosion-proof valve; 42. Second explosion-proof valve; 50. Longitudinal beam; 51. Third through hole; 80. Battery cell; 90. Enclosure plate; 101. Installation space; 102. Negative pressure chamber; 103. Buffer zone; 104. Normal pressure chamber; 105. Base plate. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0032] The following is combined with Figures 1 to 9 The following describes embodiments of the present invention.

[0033] According to an embodiment of the present invention, in a first aspect, a battery pack is provided, including a side beam 10 and a second elastic membrane 30. For example... Figure 2 As shown, the side beam 10 encloses and forms an installation space 101; the installation space 101 is suitable for installing the battery cell 80, and a hollow cavity is formed inside the side beam 10, which extends along the length of the side beam 10 to form a channel; the side beam 10 also includes a partition structure 20, such as Figure 6 As shown, the separating structure 20 includes a first elastic membrane 21; as Figure 7 As shown, the first elastic membrane 21 is transverse to the length direction of the side beam 10 and disposed within the side beam 10, so as to divide the hollow cavity of the side beam 10 into a negative pressure chamber 102 and a normal pressure chamber 104 in the length extension direction of the side beam 10. Please refer to [link to relevant documentation]. Figure 3A first through hole 14 is provided on the side of the side beam 10. The first through hole 14 is suitable for connecting the negative pressure chamber 102 and the installation space 101. The first through hole 14 is suitable for corresponding to the battery cell exhaust structure. Figure 2 and Figure 9 As shown, the second elastic membrane 30 covers the first through hole 14 to isolate the negative pressure chamber 102 from the installation space 101; wherein the pressure in the negative pressure chamber 102 is preset to be lower than atmospheric pressure.

[0034] For the battery pack used in this embodiment, please refer to [link / reference]. Figure 7 or Figure 8 When cell 80 thermally runs away and vents to the installation space 101, the high-temperature jet breaks through the melted part of the second elastic membrane 30 and is drawn into the negative pressure chamber 102. The space of the negative pressure chamber 102 can play the role of buffering, cooling and pressure drop, thereby slowing down the rate of heat spread inside the battery pack, providing more time for passengers to handle emergencies and escape from the vehicle, and improving the overall safety of the battery pack.

[0035] It should be noted that the first elastic membrane 21 is suitable to be ruptured by high-pressure gas, and the second elastic membrane 30 is suitable to be ruptured by the high-temperature jet discharged from the battery cell 80.

[0036] It should be noted that you should refer to [link / reference]. Figure 3 , Figure 3 The dashed line with an arrow indicates the gas flow path within the first side beam 11; please refer to [link / reference]. Figure 5 , Figure 5 The dashed lines with arrows indicate the flow path of gas within the longitudinal beam 50 and the second side beam 12.

[0037] It should be noted that the negative pressure in the negative pressure chamber 102 is lower than the pressure difference that causes the first elastic membrane 21 and the second elastic membrane 30 to break, so as to avoid damaging the first elastic membrane 21 and the second elastic membrane 30 when negative pressure is formed.

[0038] Specifically, the first elastic membrane 21 and the second elastic membrane 30 are thermoplastic polyurethane films.

[0039] In one embodiment, such as Figure 1 As shown, the battery pack also includes a first explosion-proof valve, the first explosion-proof valve 41 being connected to the normal pressure chamber 104 and the external environment.

[0040] Specifically, the first explosion-proof valve 41 is installed on the side beam 10.

[0041] In one embodiment, the pressure differential at which the second elastic diaphragm 30 breaks down is higher than that at which the first elastic diaphragm 21 breaks down; and the pressure differential at which the second elastic diaphragm 30 breaks down is higher than the opening pressure of the first explosion-proof valve 41. Since the pressure differential at which the second elastic diaphragm 30 breaks down is higher than both the pressure differential at which the first elastic diaphragm 21 breaks down and the opening pressure of the first explosion-proof valve 41, the pressure in the negative pressure chamber 102 increases, ensuring that the first elastic diaphragm 21 breaks down preferentially. This prevents backflow caused by gas rupturing the intact portion of the second elastic diaphragm 30, thus avoiding the impact of high-temperature gas on the uncontrolled battery cell 80.

[0042] It should be noted that the pressure difference between the first elastic membrane 21 and the second elastic membrane 30 can be determined by the combined effect of the internal volume of the battery pack, the volume of the negative pressure chamber 102, the gas generation rate of the battery cell 80, and the opening pressure of the first explosion-proof valve 41.

[0043] It should be noted that if the pressure difference of the second elastic membrane 30 is lower than that of the first elastic membrane 21, when the pressure in the negative pressure chamber 102 starts to rise, the other intact parts of the second elastic membrane 30 will be damaged by the pressure before the first elastic membrane 21 is damaged. In this case, the high temperature gas in the negative pressure chamber 102 will flow back into the installation space 101 and affect the uncontrolled battery cell 80, which may cause the normal battery cell 80 to quickly experience thermal runaway.

[0044] Furthermore, if the pressure difference at which the second elastic membrane 30 breaks is higher than that at which the first elastic membrane 21 breaks, but is lower than the opening pressure of the first explosion-proof valve 41, after the first elastic membrane 21 breaks, gas enters the atmospheric pressure chamber 104. Before the gas pressure in the atmospheric pressure chamber 104 reaches the opening pressure of the first explosion-proof valve 41, the other intact parts of the second elastic membrane 30 will break due to pressure, and high-temperature gas will still flow back into the installation space 101, which will lead to thermal runaway of the normal battery cell 80. Therefore, it is preferable that the pressure difference at which the second elastic membrane 30 breaks is higher than that at which the first elastic membrane 21 breaks and the opening pressure of the first explosion-proof valve 41.

[0045] In one embodiment, the opening pressure of the first explosion-proof valve 41 is preferably 5 kPa ± 1 kPa, the rupture pressure difference of the first elastic membrane 21 is set to 3 kPa ± 1 kPa, and the rupture pressure difference of the second elastic membrane 30 is set to 12 kPa ± 1 kPa.

[0046] Furthermore, the internal volume of the battery pack is approximately 20L, the volume of the negative pressure chamber 102 inside the first side beam 11 is approximately 12L, and the gas generation rate of the battery cell 80 is approximately 7L / s.

[0047] In one embodiment, such as Figure 2As shown, the side beam 10 includes a first side beam 11, a second side beam 12, and a third side beam 13. Two first side beams 11 are spaced apart along a first direction, and the second side beams 12 and 13 are spaced apart along a second direction. The first and second directions intersect. The two ends of the first side beam 11 are connected to the second side beam 12 and the third side beam 13 respectively, to enclose and form an installation space 101. Figure 7 As shown, a negative pressure cavity 102 is formed in the first side beam 11, and a first through hole 14 is opened on the side of the first side beam 11 facing the installation space 101. At least one partition structure 20 is provided in the first side beam 11 so that at least one end of the negative pressure cavity 102 is adapted to connect to the normal pressure cavity 104.

[0048] Specifically, negative pressure cavities 102 are formed within both first side beams 11, such as... Figure 3 As shown, several first through holes 14 are evenly provided on the first side beam 11 along the second direction, and the several first through holes 14 are arranged in a one-to-one correspondence with several exhaust structures of the battery cell.

[0049] It should be noted that, in some embodiments not shown, negative pressure cavities 102 may also be formed in the second side beam 12 and the third side beam 13, thereby expanding the space for buffering and pressure drop.

[0050] It should be noted that the length direction of the first side beam 11 is also the second direction, and the length direction of the second side beam 12 is also the first direction; the first elastic membrane 21 is transverse to the length direction of the side beam 10 and is disposed within the side beam 10. That is, when the first elastic membrane 21 is disposed within the first side beam 11, the first elastic membrane 21 is perpendicular to the second direction, and when the first elastic membrane 21 is disposed within the second side beam 12, the first elastic membrane 21 is perpendicular to the first direction.

[0051] In one embodiment, such as Figure 7 As shown, the battery pack also includes: a battery cell 80, a top cover assembly (not shown in the figure) and a bottom plate 105; the battery cell 80 is disposed in the mounting space 101 of the battery pack; the top cover assembly is disposed on the top of the side beam 10 along the thickness direction of the battery pack and is connected to the side beam 10; the bottom plate 105 is disposed on the bottom of the side beam 10 along the thickness direction of the battery pack and is connected to the side beam 10.

[0052] In one embodiment, such as Figure 1 As shown, there are several battery cells 80, and the several battery cells 80 are arranged in several rows along the first direction.

[0053] It is understood that in this embodiment, the battery cell 80 can be a square hard-shell battery cell in various blade or half-blade (also known as a short blade or dagger) forms. The venting structure of the battery cell 80 is typically located at both ends along its length.

[0054] Specifically, the battery cells 80 are arranged in several rows along the first direction, and the exhaust structure in each row of battery cells 80 is arranged facing the first side beam 11 to correspond to the first through hole 14.

[0055] In one embodiment, the battery pack further includes a heat insulation structure (not shown in the figure), and a plurality of battery cells 80 are arranged along a second direction, with the heat insulation structure disposed between two adjacent battery cells 80 along the second direction. By providing the heat insulation structure, heat transfer between two adjacent battery cells 80 is blocked, preventing heat diffusion and thus slowing down the rate of thermal runaway.

[0056] Specifically, in this embodiment, the thermal insulation structure is an aerogel felt.

[0057] Of course, in other alternative implementations, the insulation structure can also be a vacuum insulation panel, etc.

[0058] In one embodiment, see Figure 6 The partition structure 20 also includes an insert plate 22, which is disposed within the first side beam 11. The insert plate 22 has a second through hole adapted to connect the negative pressure chamber 102 and the normal pressure chamber 104. A first elastic membrane 21 is disposed on the insert plate 22 and covers the second through hole. The partition structure 20 is inserted into the first slot 111. When the first elastic membrane 21 is damaged, the partition structure 20 can be removed to replace the first elastic membrane 21, facilitating maintenance and reducing maintenance costs.

[0059] Specifically, such as Figure 3 and Figure 4 As shown, the first side beam 11 has a first slot 111; as Figure 7 As shown, the insert plate 22 is inserted into the first slot 111 (that is, the partition structure 20 is inserted into the first slot 111) so that a negative pressure cavity 102 is formed between one end of the first side beam 11 and the partition structure 20 in the length direction of the first side beam 11, and at least a part of the normal pressure cavity 104 is formed between the partition structure 20 and the other end of the first side beam 11.

[0060] It should be noted that, in order to prevent the insert plate 22 from being dislodged from the first slot 111 due to vibration, after the insert plate 22 is inserted into the first slot 111, the insert plate 22 can be fixed by spot welding at the corresponding edges of the insert plate 22 and the first slot 111, and glue can be applied to the edges where the insert plate 22 is inserted.

[0061] Specifically, the first slot 111 is formed by pre-cutting an opening on the first side beam 11.

[0062] Furthermore, such as Figure 3 and Figure 4 As shown, a third slot 113 is also provided on the first side beam 11, and the third slot 113 is spaced apart from the first slot 111, as shown. Figure 7As shown, the battery pack also includes a sealing plate 90, which is inserted into the third slot 113, and a negative pressure cavity 102 is formed between the sealing plate 90 and the partition structure 20.

[0063] It should be noted that the sealing plate 90 is a solid plate. The sealing plate 90 blocks the flow of gas so as to form a negative pressure cavity 102 between the sealing plate 90 and the partition structure 20. When high pressure gas enters the first side beam 11, the first elastic membrane 21 at the first slot 111 is broken by the high pressure gas, and the negative pressure cavity 102 is connected to the normal pressure cavity 104. The sealing plate 90 at the third slot 113 is always in a closed state.

[0064] For details, please refer to Figure 4 The first side beam 11 is provided with an air extraction hole 112, through which air is extracted from the negative pressure chamber 102 so that a negative pressure is formed inside the negative pressure chamber 102.

[0065] It should be noted that after the negative pressure chamber 102 is evacuated, a rubber plug or an interference fit plug structure, along with sealant, is required to block and seal the evacuation port.

[0066] It should be noted that in some embodiments not shown, the partition structure 20 further includes a first plate and a second plate, which are spaced apart. The partition structure 20 has a fourth through hole that penetrates the first plate and the second plate. A first elastic membrane 21 is disposed between the first plate and the second plate and abuts against the first plate and the second plate respectively. The first elastic membrane 21 covers the fourth through hole.

[0067] It is worth noting that the first elastic membrane 21 is located between the first plate and the second plate. When the first elastic membrane 21 needs to be replaced, it can be easily replaced simply by pulling out the first elastic membrane 21.

[0068] In one embodiment, such as Figure 2 As shown, the battery pack also includes: a longitudinal beam 50; the longitudinal beam 50 extends along the second direction and is disposed within the mounting space 101, the longitudinal beam 50 is connected to the second side beam 12, the interior of the longitudinal beam 50 is connected to the interior of the second side beam 12, and a negative pressure cavity 102 is formed therein, as shown. Figure 5 As shown, a third through hole 51 is provided on the side of the longitudinal beam 50. The third through hole 51 is suitable for connecting the negative pressure chamber 102 and the installation space 101. The third through hole 51 is suitable for corresponding to the cell exhaust structure, such as... Figure 2 and Figure 9 As shown, the second elastic membrane 30 covers the third through hole 51 to isolate the negative pressure chamber 102 from the installation space 101, as... Figure 7 As shown, at least one partition structure 20 is provided in the second side beam 12 so that at least one end of the negative pressure chamber 102 forms a normal pressure chamber 104.

[0069] It is worth noting that by forming a negative pressure cavity 102 within the connected longitudinal beam 50 and the second side beam 12, more space is provided to buffer, cool, and reduce pressure, thereby further slowing down the rate of increase in internal air pressure and temperature of the battery pack and delaying the rate of thermal spread of the entire battery pack.

[0070] Specifically, the third through hole 51 is provided with several at intervals.

[0071] For details, please refer to Figure 1 The longitudinal beam 50 divides the installation space 101 into two parts, and battery cells 80 are provided on both sides of the longitudinal beam 50 along the first direction.

[0072] Specifically, the venting structure of cell 80 is usually located at both ends along the length of cell 80. Please refer to [link / reference]. Figure 7 Two rows of battery cells 80 are arranged along the first direction. The exhaust structure in each row of battery cells 80 is respectively arranged facing the first side beam 11 and the longitudinal beam 50 to correspond to the first through hole 14 and the third through hole 51, so as to absorb the high temperature gas discharged by the battery cells by utilizing the negative pressure cavity 102 formed in the first side beam 11, the second side beam 12 and the longitudinal beam 50.

[0073] It should be noted that in other alternative embodiments, the number of longitudinal beams 50 can be increased according to the actual situation to increase the volume of the negative pressure chamber, thereby enhancing the effect of slowing down the rate of heat spread inside the battery pack.

[0074] Specifically, such as Figure 5 As shown, two second slots 121 are provided on the second side beam 12, as... Figure 7 As shown, two partition structures 20 are respectively inserted into two second slots 121, so that a partial negative pressure cavity 102 is formed between the two partition structures 20 in the length direction of the second side beam 12, and a partial normal pressure cavity 104 is formed between the partition structure 20 and the end of the second side beam 12.

[0075] In other alternative embodiments, the second side beam 12 may also have a partition structure 20 at only one end and be closed at the other end.

[0076] It should be noted that you should refer to [link / reference]. Figure 7 When the exhaust structure of the battery cell 80 is directed toward the first side beam 11 and the longitudinal beam 50, the high-temperature jet breaks through and melts the second elastic membrane 30, and the gas enters the negative pressure chamber 102. The first elastic membrane 21 in the first side beam 11 and the second side beam 12 is destroyed by the high-pressure gas, and the gas enters the normal pressure chamber 104. The gas pressure in the normal pressure chamber 104 exceeds the opening pressure of the first explosion-proof valve 41, and then the first explosion-proof valve 41 opens to release pressure.

[0077] It should be noted that you should refer to [link / reference]. Figure 8 When the exhaust structure of the battery cell 80 faces only the first side beam 11, the high-temperature jet breaks through and melts the second elastic membrane 30. The gas enters the negative pressure chamber 102 in the first side beam 11. After the first elastic membrane 21 in the first side beam 11 is destroyed by the high-pressure gas, the gas enters the normal pressure chamber 104. The gas pressure does not exceed the opening pressure of the first explosion-proof valve 41. The gas will break through the first elastic membrane 21 in the second side beam 12. The negative pressure chamber 102 in the second side beam 12 is connected to the normal pressure chamber 104. The negative pressure chamber 102 in the second side beam 12 produces a suction effect, which further slows down the rate of increase of gas pressure and temperature inside the battery pack, thereby delaying the rate of heat spread of the entire pack. When the gas pressure in the negative pressure chamber 102 and the normal pressure chamber 104 exceeds the opening pressure of the first explosion-proof valve 41, the first explosion-proof valve 41 opens to release pressure.

[0078] In one embodiment, such as Figure 1 As shown, a buffer zone 103 is also provided within the side beam 10. The buffer zone 103 is spaced apart from the area where the battery cell 80 is located. The buffer zone 103 is adapted to have a buffer structure to buffer the impact force on the battery pack from the third side beam 13 to the first side beam 11. A second explosion-proof valve 42 is provided on the third side beam 13. The second explosion-proof valve 42 is adapted to connect the external environment and the buffer zone. When the discharge rate of the first explosion-proof valve 41 is lower than the discharge rate of the battery cell 80, the gas pressure in the battery pack will continue to rise. The high-pressure gas will push the top cover assembly upward, and the gas will enter the buffer zone from the area where the battery cell 80 is located. When the gas pressure in the buffer zone exceeds the opening pressure of the second explosion-proof valve 42, the second explosion-proof valve 42 on the third side beam 13 opens and begins rapid venting, further improving the safety of the battery pack.

[0079] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A battery pack, characterized in that, include: Side beam (10), the side beam (10) encloses to form an installation space (101), the installation space (101) is suitable for installing battery cell (80), a hollow cavity is formed inside the side beam (10), the hollow cavity extends along the length direction of the side beam (10) to form a channel; The side beam (10) further includes a partition structure (20), the partition structure (20) includes a first elastic membrane (21), the first elastic membrane (21) is transverse to the length direction of the side beam (10) and disposed in the side beam (10) to divide the hollow cavity into a negative pressure cavity (102) and a normal pressure cavity (104); The side beam (10) has a first through hole (14) on its side. The first through hole (14) is adapted to connect the negative pressure chamber (102) and the installation space (101). The first through hole (14) is adapted to be set in accordance with the cell exhaust structure. A second elastic membrane (30) covers the first through hole (14) to separate the negative pressure chamber (102) from the installation space (101); The pressure inside the negative pressure chamber (102) is preset to be lower than atmospheric pressure.

2. The battery pack according to claim 1, characterized in that, Also includes: The first explosion-proof valve (41) connects the atmospheric pressure chamber (104) to the external environment.

3. The battery pack according to claim 2, characterized in that, The rupture pressure differential of the second elastic membrane (30) is higher than that of the first elastic membrane (21); and / or, the rupture pressure differential of the second elastic membrane (30) is higher than that of the opening pressure of the first explosion-proof valve (41).

4. The battery pack according to claim 3, characterized in that, The opening pressure of the first explosion-proof valve (41) is 5KPa±1KPa, the rupture pressure difference of the first elastic membrane (21) is 3KPa±1KPa, and the rupture pressure difference of the second elastic membrane (30) is 12KPa±1KPa.

5. The battery pack according to any one of claims 1 to 4, characterized in that, The side beam (10) includes a first side beam (11), a second side beam (12), and a third side beam (13). Two first side beams (11) are spaced apart along a first direction. The second side beams (12) and the third side beams (13) are spaced apart along a second direction. The first direction and the second direction intersect. The two ends of the first side beam (11) are connected to the second side beam (12) and the third side beam (13) respectively to enclose and form the installation space (101). The negative pressure cavity (102) is formed in the first side beam (11). The first through hole (14) is opened on the side of the first side beam (11) facing the installation space (101). At least one of the partition structures (20) is provided in the first side beam (11) so that at least one end of the negative pressure cavity (102) is suitable for connecting to the normal pressure cavity (104).

6. The battery pack according to claim 5, characterized in that, The partition structure (20) further includes a insert plate (22), which is disposed in the first side beam (11). The insert plate (22) has a second through hole, which is adapted to connect the negative pressure chamber (102) and the normal pressure chamber (104). The first elastic membrane (21) is disposed on the insert plate (22) and covers the second through hole.

7. The battery pack according to claim 5, characterized in that, The battery pack also includes: A longitudinal beam (50) extends along a second direction and is disposed within the installation space (101). The longitudinal beam (50) is connected to a second side beam (12). The interior of the longitudinal beam (50) is connected to the interior of the second side beam (12) and a negative pressure chamber (102) is formed therein. A third through hole (51) is provided on the side of the longitudinal beam (50). The third through hole (51) is adapted to connect the negative pressure chamber (102) and the installation space (101). The third through hole (51) is adapted to correspond to the cell exhaust structure. A second elastic membrane (30) covers the third through hole (51) to separate the negative pressure chamber (102) from the installation space (101). At least one of the partition structures (20) is provided in the second side beam (12) so that at least one end of the negative pressure chamber (102) forms the normal pressure chamber (104).

8. The battery pack according to any one of claims 1-4, characterized in that, The battery pack also includes: A battery cell (80) is disposed within the mounting space (101); The top cover assembly is disposed on the top of the side beam (10) and connected to the side beam (10) along the thickness direction of the battery pack; The base plate (105) is disposed at the bottom of the side beam (10) along the thickness direction of the battery pack and is connected to the side beam (10).

9. The battery pack according to claim 8, characterized in that, The battery cell (80) is provided in a plurality of columns, and the plurality of battery cells (80) are arranged in a plurality of columns along a first direction.

10. The battery pack according to claim 9, characterized in that, The battery pack also includes a heat insulation structure. A plurality of the battery cells (80) are arranged along the second direction, and the heat insulation structure is disposed between two adjacent battery cells (80) along the second direction.

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