Battery pack and energy storage device

Abstract

The application provides a battery pack and an energy storage device. The battery pack comprises a first shell, an insulating liquid, a second shell and a cell assembly. The first shell comprises a first accommodating cavity with a first opening, the insulating liquid is arranged in the first accommodating cavity, a liquid level of the insulating liquid is lower than the first opening, the second shell is connected with the first shell, the second shell comprises a second accommodating cavity with a second opening, at least part of the second shell is located in the first accommodating cavity, the second opening is located in the first accommodating cavity and the insulating liquid immerses the second opening, and at least part of the cell assembly is located in the second accommodating cavity.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery pack and an energy storage device. Background Technology

[0002] A battery pack is a device that can continue to be used after the battery cells have been discharged, by recharging to reactivate the active materials. Battery packs are commonly used in energy storage devices. Improving the safety of battery packs is one of the research directions in battery technology development. Summary of the Invention

[0003] In view of the above problems, this application provides a battery pack and an energy storage device, which helps to improve the safety of the battery pack.

[0004] This application provides a battery pack including a first housing, an insulating liquid, a second housing, and a cell assembly. The first housing includes a first receiving cavity with a first opening, the insulating liquid is disposed in the first receiving cavity, the liquid level of the insulating liquid is lower than the first opening, the second housing is connected to the first housing, the second housing includes a second receiving cavity with a second opening, at least a portion of the second housing is located in the first receiving cavity, the second opening is located in the first receiving cavity and the insulating liquid submerges the second opening, and at least a portion of the cell assembly is located in the second receiving cavity.

[0005] In the battery pack of this embodiment, an insulating liquid is disposed within the first housing. The cell assembly is connected to the second housing, and at least a portion of the cell assembly is immersed in the insulating liquid. The insulating liquid also submerges the second opening of the second housing. The insulating liquid acts as an air barrier, reducing the likelihood of the cell coming into contact with oxygen outside the second housing in the event of thermal runaway. This controls the scale of combustible gas combustion and reduces the possibility of open flames from thermal runaway spreading to other normal cells. Furthermore, the insulating liquid absorbs the heat generated by the thermally runaway cell, dissipating heat and cooling the cell, further reducing the possibility of heat conduction from the thermally runaway cell to other normal cells, thus improving the safety of the battery pack. Both the first and second housings provide protection for the cell assembly, enhancing the safety of the cell assembly and the overall battery pack.

[0006] In one or more of the above optional embodiments, the first housing includes a first bottom wall and a first peripheral wall, the first bottom wall and the first peripheral wall are connected to form a first receiving cavity, the second housing includes an extension wall, a second bottom wall and a second peripheral wall, the second bottom wall and the second peripheral wall are connected to form a second receiving cavity, the extension wall is connected to the first peripheral wall and the second peripheral wall, and the second housing closes the first opening.

[0007] The first housing and the second housing are connected and fixed by an extension wall, which improves the connection strength between the first housing and the second housing.

[0008] By sealing the first opening with an extension wall, the extension wall can play a protective role. It can prevent external air or dust from coming into contact with the insulating liquid, and it can also reduce the possibility of the insulating liquid overflowing through the first opening.

[0009] In one or more of the above optional embodiments, the second opening is disposed facing the first bottom wall, a first gap is formed between the first bottom wall and the cell assembly, the first gap is filled with insulating liquid, a second gap is formed between the first peripheral wall and the second peripheral wall and communicates with the first gap, and at least a portion of the second gap is filled with insulating liquid.

[0010] The insulating liquid in the first gap can contact the cell assembly to dissipate heat and cool it. The insulating liquid filling the first gap restricts the air from entering the second cavity from the second gap, further reducing the possibility of the cell assembly coming into contact with oxygen outside the second cavity. In the event of thermal runaway in the cell, this helps control the scale of combustible gas combustion, reduces the possibility of open flames from thermal runaway spreading to other normal cells, and improves the safety of the battery pack.

[0011] In one or more of the above optional embodiments, the battery pack includes an exhaust section configured to discharge gas generated by the cell assembly to the outside of the battery pack, and a first gap and a second gap configured to discharge gas generated by the cell assembly.

[0012] When a cell in a battery pack experiences thermal runaway, the cell releases high-temperature, high-pressure gas to relieve internal pressure, reducing the likelihood of a sustained pressure rise and explosion, thus improving cell safety. The released high-temperature, high-pressure gas flows through a first and second gap to the exhaust section. As the gas flows through these gaps, it is cooled by the insulating liquid, resulting in a decrease in temperature and pressure. This reduces the internal pressure of the battery pack and lowers the temperature of the gas exiting the pack. The exhaust section opens when it reaches the withstand pressure threshold, releasing the internal pressure and expelling the gas, further reducing the risk of a sustained pressure rise and explosion, and enhancing battery pack safety.

[0013] In one or more of the above optional embodiments, the first peripheral wall is provided with an exhaust section, and the liquid level of the insulating liquid is lower than the exhaust section.

[0014] By keeping the level of the insulating liquid below the vent, the amount of insulating liquid discharged to the outside of the first casing is reduced after the vent is opened. This reduces the possibility of insufficient insulating liquid due to excessive discharge, allowing the insulating liquid to continuously dissipate heat and cool the thermally runaway cell. It also reduces the possibility of heat from the thermally runaway cell being conducted to other normal cells, thus improving the safety of the battery pack.

[0015] In one or more of the above optional embodiments, end plates are respectively provided on opposite sides of the battery cell assembly, the end plates are connected and fixed to the first bottom wall, and at least part of the end plates have a third gap with the first bottom wall, the third gap being filled with insulating liquid.

[0016] The end plate can press the battery cells in the battery cell assembly, forming a limiting constraint on the cells and reducing their expansion. The end plate also protects the battery cell assembly, improving its safety. The first and second gaps are connected to the third gap, which is configured to allow gas to pass through. The high-temperature, high-pressure gas released from the battery cells can pass through the first, third, and second gaps and flow to the exhaust section, reducing the possibility of the end plate creating resistance to gas flow and thus improving the safety of the battery pack.

[0017] In one or more of the above optional embodiments, the battery cell assembly includes a plurality of battery cells arranged along a first direction. Each battery cell has a pressure relief portion, which is spaced apart from the first bottom wall. Along the first direction, at least a portion of the projection of the pressure relief portion is located within the projection of the end plate, and at least a portion of the pressure relief portion is wetted by insulating liquid.

[0018] In one or more of the above optional embodiments, the first direction is the thickness direction of the battery cell.

[0019] At least part of the pressure relief section is immersed in the insulating liquid. In the event of thermal runaway of the battery cell, the gas discharged from the pressure relief section can first enter the insulating liquid. During the flow of the gas inside the insulating liquid, both the temperature and flow rate of the gas will decrease. When the gas is discharged from the surface of the insulating liquid, the amount of insulating liquid carried by the gas is relatively reduced.

[0020] In one or more of the above optional embodiments, the battery pack includes a connector and a conductive element, the connector is disposed in the first housing, the conductive element connects the cell assembly and the connector, and an insulating liquid immerses at least a portion of the conductive element.

[0021] The method of immersing at least part of the conductive component in an insulating liquid enables heat exchange between the insulating liquid and the conductive component, thereby dissipating heat and cooling the conductive component and reducing the possibility of the conductive component overheating.

[0022] In one or more of the above alternative embodiments, the second housing includes a third receiving cavity having a third opening, the second receiving cavity and the third receiving cavity being isolated from each other, the third opening being located within the first receiving cavity and the third opening being submerged by an insulating liquid, and the third receiving cavity being configured to receive electronic devices connected to the cell assembly.

[0023] The second and third receiving cavities are independently configured and not connected to each other. The battery cell assembly is isolated from the electronic components in the third receiving cavity. If the electronic components in the third receiving cavity are damaged or fail, the impact on the safety of the battery cell assembly is minimal, which helps to improve the safety of the battery cell assembly.

[0024] The insulating liquid immerses at least a portion of the electronic device, thereby dissipating heat and cooling the electronic device, reducing the possibility of the electronic device malfunctioning due to excessive temperature, and improving the safety of the battery cell assembly.

[0025] In one or more of the above optional embodiments, the battery pack includes a circuit board connected to the cell assembly. The circuit board is disposed on the side of the cell assembly facing the first bottom wall. A first gap provides mounting space for the circuit board, reducing the possibility of positional interference between the circuit board and the first bottom wall. An insulating liquid is used to immerse the circuit board, enhancing its insulation protection.

[0026] In one or more of the above optional embodiments, the battery cell has an electrical connection portion connected to a circuit board, and the electrical connection portion is immersed in an insulating liquid to enhance the insulation protection of the electrical connection portion.

[0027] In one or more of the above optional embodiments, the end plate extends 2 to 3 millimeters beyond the pressure relief portion along the second direction, which is a vertical direction.

[0028] In one or more of the above optional embodiments, the first bottom wall and the second peripheral wall are spaced apart, such that the second gap and the first gap are connected.

[0029] In one or more of the above optional embodiments, the second peripheral wall is connected to the first bottom wall, and the second peripheral wall is provided with a through hole so that the second gap and the first gap are connected.

[0030] This application provides an energy storage device, which includes a battery pack. Attached Figure Description

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1This is a schematic diagram of the structure of a battery pack provided in one embodiment of this application; Figure 2 This is a partially exploded structural diagram of a battery pack provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the second housing provided in one embodiment of this application; Figure 4 This is a cross-sectional view of a battery pack provided in an embodiment of this application; Figure 5 This is a cross-sectional view of a battery pack without insulating liquid provided in one embodiment of this application; Figure 6 This is a schematic diagram of the connection structure of the battery cell assembly and the end plate provided in an embodiment of this application; Figure 7 This is a partial cross-sectional view of a battery pack provided in an embodiment of this application; Figure 8 This is a partial cross-sectional view of a battery pack provided in an embodiment of this application; Figure 9 This is a schematic diagram of the structure of the second housing provided in another embodiment of this application; Figure 10 This is a cross-sectional structural diagram of a battery pack provided in another embodiment of this application.

[0032] Explanation of reference numerals in the attached figures: 10. Battery pack; 101. First gap; 102. Second gap; 103. Third gap; 104. Circuit board; 20. First housing; 201. First receiving cavity; 2011. First opening; 21. First bottom wall; 22. First perimeter wall; 23. Sealing part; 30. Insulating liquid; 40. Second housing; 401. Second receiving cavity; 4011. Second opening; 402. Third receiving cavity; 4021. Third opening; 41. Second bottom wall; 42. Second peripheral wall; 43. Extension wall; 50. Battery cell assembly; 51. Battery cell; 511. Pressure relief section; 512. Electrical connection section; 60. Exhaust section; 70. End plate; 80. Connector; 90. Conductive components; 100. Electronic components; 110. Fasteners; 120. Sealing gasket; X, first direction; Y, the second direction; Z, Third-party orientation. Detailed Implementation

[0033] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0034] It should be noted that, unless otherwise stated, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by those skilled in the art to which the embodiments of this application pertain.

[0035] In the description of the embodiments of this application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of 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. Therefore, they should not be construed as limitations on the embodiments of this application.

[0036] Furthermore, technical terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise explicitly defined.

[0037] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" 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. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0038] See Figures 1 to 4 As shown, this application embodiment provides a battery pack 10, which includes a first housing 20, an insulating liquid 30, a second housing 40, and a cell assembly 50. The insulating liquid 30 is disposed within the first housing 20, and at least a portion of the cell assembly 50 is disposed within the second housing 40. The cell assembly 50 includes a plurality of cells 51. The second housing 40 can protect the cell assembly 50.

[0039] In one feasible manner, a plurality of battery cells 51 are arranged along a first direction X. The first direction X is the thickness direction of the battery cells 51.

[0040] In one example, cell 51 is a square cell 51, the second direction Y is the width direction of cell 51, and the third direction Z is the length direction of cell 51. The first direction X, the second direction Y, and the third direction Z are all perpendicular to each other. Battery pack 10 as follows. Figure 4 When placed on the ground, the second direction Y is the vertical direction.

[0041] In one possible implementation, the first housing 20 includes a first receiving cavity 201 having a first opening 2011, and an insulating liquid 30 is disposed within the first receiving cavity 201, the liquid level of the insulating liquid 30 being below the first opening 2011. A second housing 40 is connected to the first housing 20, and the second housing 40 includes a second receiving cavity 401 having a second opening 4011, at least a portion of the second housing 40 being located within the first receiving cavity 201, the second opening 4011 being located within the first receiving cavity 201 and submerged by the insulating liquid 30, and at least a portion of the battery cell assembly 50 being located within the second receiving cavity 401.

[0042] The assembly process of the battery pack 10 may include: placing the cell assembly 50 into the first housing 20, then inserting the second housing 40 into the first receiving cavity 201 along the second direction Y, and then injecting insulating liquid 30 into the first receiving cavity 201.

[0043] The insulating liquid 30 itself has good cooling and insulation properties. The insulating liquid 30 immerses at least a portion of the battery cell assembly 50, and the insulating liquid 30 can provide physical insulation and isolation for the battery cell assembly 50, reducing the possibility of electrical connection between the battery cell assembly 50 and other conductive parts 90. At the same time, the insulating liquid 30 also has the function of isolating the battery cell assembly 50 from the air.

[0044] Under normal operating conditions, the insulating liquid 30 can absorb the heat generated by the battery cell 51, enabling the battery cell 51 to effectively dissipate heat and cool down, maintaining the battery cell 51 at its normal operating temperature, which is beneficial to improving the performance of the battery cell 51.

[0045] When the battery cell 51 inside the battery pack 10 experiences thermal runaway, it will generate high-temperature substances, such as flammable gases or high-temperature particulate matter. The internal temperature and pressure of the battery pack 10 may continue to rise, which could lead to structural failure of the battery pack 10 and cause abnormalities.

[0046] The insulating liquid 30 acts as an air barrier, reducing the likelihood of cell 51 coming into contact with oxygen in the event of thermal runaway, preventing the combustion of flammable gases, and reducing the possibility of open flames from thermal runaway spreading to other normal cells 51. In addition, the insulating liquid 30 absorbs the heat generated by the thermally runaway cell 51, dissipating heat and cooling the thermally runaway cell 51, reducing the possibility of heat from the thermally runaway cell 51 being conducted to other normal cells 51, which helps to improve the safety of the battery pack 10.

[0047] In one feasible manner, the insulating liquid 30 comprises liquid insulating oil.

[0048] In one feasible manner, the insulating liquid 30 includes at least one of hydrocarbon synthetic oil, silicone oil, and synthetic ester.

[0049] In one feasible manner, the vaporization point of the insulating liquid 30 is 500° to 600°.

[0050] In the battery pack 10 of this embodiment, an insulating liquid 30 is disposed inside the first housing 20. The cell assembly 50 is connected to the second housing 40, and at least a portion of the cell assembly 50 is immersed in the insulating liquid 30. The insulating liquid 30 also submerges the second opening 4011 of the second housing 40, thus acting as an air barrier. In the event of thermal runaway of the cell 51, the likelihood of the cell 51 coming into contact with oxygen outside the second housing 401 is reduced, controlling the scale of combustible gas combustion and reducing the possibility of open flames from thermal runaway spreading to other normal cells 51. Furthermore, the insulating liquid 30 absorbs the heat generated by the thermally runaway cell 51, dissipating heat and cooling the thermally runaway cell 51, reducing the possibility of heat conduction from the thermally runaway cell 51 to other normal cells 51, thereby improving the safety of the battery pack 10. Both the first housing 20 and the second housing 40 can protect the cell assembly 50, improving the safety of the cell assembly 50 and the battery pack 10.

[0051] In one feasible approach, see Figures 2 to 4 As shown, the first housing 20 includes a first bottom wall 21 and a first peripheral wall 22, which are connected to form a first receiving cavity 201. The second housing 40 includes an extension wall 43, a second bottom wall 41, and a second peripheral wall 42, which are connected to form a second receiving cavity 401. The extension wall 43 connects the first peripheral wall 22 and the second peripheral wall 42. The second housing 40 closes the first opening 2011.

[0052] The first housing 20 and the second housing 40 are connected and fixed by the extension wall 43, thereby improving the connection strength between the first housing 20 and the second housing 40.

[0053] The extension wall 43 can play a protective role. It can prevent external air or dust from coming into contact with the insulating liquid 30, and can also reduce the possibility of the insulating liquid 30 overflowing through the first opening 2011.

[0054] In one example, the extension wall 43 is an annular structural member surrounding the second peripheral wall 42. Exemplarily, the extension wall 43 is a plate-like structure.

[0055] In one example, the extension wall 43 is sealed to the first peripheral wall 22. See, for example, [link to example]. Figure 2 and Figure 4 As shown, the first housing 20 includes a sealing part 23, which is connected to the first peripheral wall 22 and surrounds the first peripheral wall 22. The extension wall 43 and the sealing part 23 can be connected and fixed by fasteners such as screws, bolts or rivets. A sealing gasket 120 can be provided between the extension wall 43 and the sealing part 23.

[0056] In one feasible embodiment, the second opening 4011 is disposed facing the first bottom wall 21, and a first gap 101 is formed between the first bottom wall 21 and the cell assembly 50, the first gap 101 being filled with insulating liquid 30. A second gap 102 is formed between the first peripheral wall 22 and the second peripheral wall 42. Insulating liquid 30 fills at least a portion of the second gap 102. See also Figure 5 As shown, Figure 5 Insulating liquid 30 is not shown. The second gap 102 and the first gap 101 are connected.

[0057] In one feasible approach, see Figure 5 The first bottom wall 21 and the second peripheral wall 42 are spaced apart, so that the second gap 102 and the first gap 101 are connected.

[0058] In another possible implementation, the second peripheral wall 42 is connected to the first bottom wall 21, and the second peripheral wall 42 is provided with a through hole (not shown) so that the second gap 102 and the first gap 101 are connected.

[0059] The insulating liquid 30 at the first gap 101 can contact the cell assembly 50 to dissipate heat and cool the cell assembly 50. The first gap 101 is filled with insulating liquid 30, which restricts the air in the second gap 102 from entering the second receiving cavity 401, further reducing the possibility of the cell assembly 50 coming into contact with oxygen outside the second receiving cavity 401. In the event of thermal runaway of the cell 51, this helps to control the scale of combustible gas combustion, reduces the possibility of open flames from thermal runaway and spread to other normal cells 51, and improves the safety of the battery pack 10.

[0060] See one example. Figure 5As shown, the battery pack 10 includes a circuit board 104 connected to the cell assembly 50. The circuit board 104 is disposed on the side of the cell assembly 50 facing the first bottom wall 21. A first gap 101 provides mounting space for the circuit board 104, reducing the possibility of positional interference between the circuit board 104 and the first bottom wall 21. See also... Figure 4 As shown, the insulating liquid 30 is immersed in the circuit board 104 to enhance the insulation protection of the circuit board 104.

[0061] In one example, board 104 can be a BMS board. In another example, board 104 can be a circuit adapter board.

[0062] See one example. Figure 6 As shown, the battery cell 51 has an electrical connection portion 512, which is connected to the circuit board 104. The insulating liquid 30 is immersed in the electrical connection portion 512 to enhance the insulation protection of the electrical connection portion 512.

[0063] Optionally, electronic components may be installed within the second gap 102. These electronic components include, but are not limited to, high-voltage boxes or circuit boards. The second housing 40 isolates the electronic components from the battery cell assembly 50. If the electronic components installed within the second gap 102 are damaged or fail, the impact on the safety of the battery cell assembly 50 is minimal, which helps to improve the safety of the battery cell assembly 50.

[0064] When the first peripheral wall 22 is deformed towards the second peripheral wall 42 under force, the second gap 102 can act as a buffer space, reducing the possibility that the first peripheral wall 22 will deform and squeeze the second peripheral wall 42, thus reducing the possibility that the deformation of the second peripheral wall 42 will squeeze the cell assembly 50, and improving the safety of the cell assembly 50.

[0065] In one example, the second opening 4011 is spaced apart from the second bottom wall 41, and the second opening 4011 is located at the lower edge of the second peripheral wall 42 away from the second bottom wall 41. The insulating liquid 30 is immersed in the lower edge of the second peripheral wall 42 away from the second bottom wall 41. Along the second direction Y, the distance between the liquid surface of the insulating liquid 30 and the lower edge of the second peripheral wall 42 is greater than or equal to 10 mm.

[0066] In one feasible approach, see Figure 2 As shown, the battery pack 10 includes a vent 60 configured to discharge gas generated by the cell assembly 50 to the outside of the battery pack 10. A first gap 101 and a second gap 102 are configured to discharge gas generated by the cell assembly 50. Optionally, the vent 60 is configured to open for pressure relief in response to the internal pressure of the battery pack 10 reaching a threshold.

[0067] When a cell 51 in the battery pack 10 experiences thermal runaway, the cell 51 releases internal pressure by venting high-temperature, high-pressure gas. This reduces the possibility of a continuous rise in internal pressure and potential explosion, thus improving the safety of the cell 51. The released high-temperature, high-pressure gas from the cell 51 can flow to the exhaust section 60 through the first gap 101 and the second gap 102. As the high-temperature, high-pressure gas flows through the first gap 101 and the second gap 102, it is cooled by the insulating liquid 30, resulting in a decrease in temperature and pressure. This reduces the gas pressure inside the battery pack 10 and also lowers the temperature of the gas exiting the battery pack 10. When the exhaust section 60 reaches the withstand pressure threshold, it opens to release the internal pressure of the battery pack 10, expelling the gas and reducing the possibility of a continuous rise in internal pressure and potential explosion, thereby improving the safety of the battery pack 10.

[0068] In one example, the exhaust section 60 includes, but is not limited to, a pressure relief valve.

[0069] In one feasible approach, see Figure 2 As shown, the first peripheral wall 22 is provided with an exhaust section 60, and the liquid level of the insulating liquid 30 is lower than that of the exhaust section 60.

[0070] When the cell 51 in the battery pack 10 experiences thermal runaway, the gas released from the cell 51 is discharged from the insulating liquid 30 at the second gap 102, and then flows to the exhaust section 60. After the exhaust section 60 is opened, the gas is discharged through the exhaust section 60.

[0071] By keeping the level of the insulating liquid 30 below that of the vent 60, the amount of insulating liquid 30 discharged to the outside of the first housing 20 is reduced after the vent 60 is opened. This reduces the possibility of insufficient insulating liquid 30 due to excessive discharge, allowing the insulating liquid 30 to continuously dissipate heat and cool the thermal runaway cell 51. This also reduces the possibility of heat from the thermal runaway cell 51 being conducted to other normal cells 51, thereby improving the safety of the battery pack 10.

[0072] In one example, the exhaust portion 60 and the first housing 20 can each be separately manufactured components. The exhaust portion 60 and the first peripheral wall 22 can be assembled by mechanical connection. In one example, the exhaust portion 60 is disposed through the first peripheral wall 22, with part of the exhaust portion 60 inside the first housing 20 and part of it outside the first housing 20.

[0073] In one feasible approach, see Figure 5 and Figure 6As shown, end plates 70 are respectively provided on opposite sides of the battery cell assembly 50. In one example, the end plates 70 are provided at both ends of the battery cell assembly 50 along the arrangement direction of the battery cells 51. The end plates 70 are connected and fixed to the first bottom wall 21. The end plates 70 have at least a third gap 103 between them and the first bottom wall 21. The third gap 103 is filled with insulating liquid 30.

[0074] The end plate 70 can press the battery cell 51 in the battery cell assembly 50, forming a limiting constraint on the battery cell 51 and reducing the expansion of the battery cell 51. The end plate 70 can also protect the battery cell assembly 50 and improve its safety. The first gap 101 and the second gap 102 are respectively connected to the third gap 103. The third gap 103 is configured to allow gas to pass through. The high-temperature and high-pressure gas released from the battery cell 51 can pass through the first gap 101, the third gap 103 and the second gap 102 and flow to the exhaust section 60, reducing the possibility of the end plate 70 causing resistance to gas flow and improving the safety of the battery pack 10.

[0075] In one example, a strap can be used to secure the end plate 70 and the cell assembly 50, reducing the likelihood of the end plate 70 and the cell assembly 50 separating and the cell assembly 50 detaching from the second housing 40. Exemplarily, the strap can be, but is not limited to, a steel strip.

[0076] In one example, the distance between the end plate 70 and the second peripheral wall 42 is 0 mm to 5 mm, and an assembly space is reserved between the end plate 70 and the second peripheral wall 42 so that the end plate 70 and the cell assembly 50 can be smoothly installed into the second receiving cavity 401. In the event of thermal runaway of the cell assembly 50, the possibility of gas entering the space between the end plate 70 and the second peripheral wall 42 and being unable to be discharged is reduced.

[0077] See one example. Figure 7 and Figure 8 As shown, the end plate 70 is connected and fixed to the first bottom wall 21 by fasteners 110 such as screws. The end plate 70 includes a mounting hole extending along the second direction Y, through which the fastener 110 passes and is connected and fixed to the first bottom wall 21. In one example, the first bottom wall 21 has a boss, and the end plate 70 has a groove that matches the boss, through which the fastener 110 passes and is connected and fixed to the boss.

[0078] In one feasible embodiment, the cell 51 has a pressure relief portion 511, which is disposed at a distance from the first bottom wall 21. At least a portion of the projection of the pressure relief portion 511 is located within the projection of the end plate 70 along the first direction X, and at least a portion of the pressure relief portion 511 is wetted by insulating liquid 30.

[0079] When thermal runaway occurs in cell 51 and gas is discharged, the gas can be blocked by end plate 70, which prolongs the gas flow path, prolongs the contact time between the gas and insulating liquid 30, increases the heat exchange between the gas and insulating liquid 30, reduces the temperature when the gas is discharged, and improves the safety of exhaust. At the same time, it is not easy for the gas to flow to the second gap 102 due to the obstruction of end plate 70.

[0080] At least a portion of the pressure relief section 511 is immersed in the insulating liquid 30. In the event of thermal runaway of the cell 51, the gas discharged from the pressure relief section 511 can first enter the insulating liquid 30. During the flow of the gas inside the insulating liquid 30, the temperature and flow rate of the gas will decrease. When the gas is discharged from the surface of the insulating liquid 30, the amount of insulating liquid 30 carried by the gas is relatively reduced.

[0081] The pressure relief section 511 is positioned towards the first bottom wall 21, and the gas discharged from the pressure relief section 511 avoids the second housing 40. This reduces the structural strength requirements of the second housing 40 for preventing heat diffusion. The material of the second housing 40 can include, but is not limited to, plastic, sheet molding compound (SMC), etc., which helps to reduce the weight of the second housing 40 and increase the energy density of the battery pack 10.

[0082] The material of the first housing 20 includes, but is not limited to, aluminum, aluminum alloy or steel. The first housing 20 has high structural strength, which improves the impact resistance of the first housing 20. When the gas discharged from the pressure relief part 511 acts on the first housing 20, the first housing 20 is not easily damaged, thus improving the safety of the battery pack 10.

[0083] In one example, cell 51 can be a pouch cell 51 or a prismatic cell 51.

[0084] In one example, the projection of the pressure relief section 511 is located within the projection of the end plate 70, and the insulating liquid 30 completely submerges the pressure relief section 511.

[0085] In one example, along the second direction Y, the end plate 70 extends 2 to 3 millimeters beyond the pressure relief section 511.

[0086] In one example, along the second direction Y, the distance between the pressure relief part 511 and the first bottom wall 21 is greater than or equal to 10 mm. The cross-sectional area of ​​the gas channel between the pressure relief part 511 and the first bottom wall 21 is relatively large, and the resistance to the gas discharge from the pressure relief part 511 is relatively small, which is conducive to the smooth exhaust of the pressure relief part 511. In addition, a safe insulation distance is maintained between the cell assembly 50 and the first bottom wall 21, which improves the safety of the cell assembly 50.

[0087] In one example, a circuit board may be disposed between the pressure relief section 511 and the first bottom wall 21 along the second direction Y, and the circuit board is separate from the first bottom wall 21.

[0088] In one feasible approach, see Figure 4 As shown, the battery pack 10 includes a connector 80 and a conductive element 90. The connector 80 is disposed in the first housing 20, and the conductive element 90 connects the cell assembly 50 and the connector 80. An insulating liquid 30 immerses at least a portion of the conductive element 90.

[0089] Connector 80 is configured to connect to an external device. Electrical power and / or signals can be transmitted between the battery pack 10 and the external device via connector 80 and conductive element 90. Optionally, the external device includes a charging device. Optionally, the electrical device includes a shared electric bicycle.

[0090] By immersing at least a portion of the conductive component 90 in the insulating liquid 30, heat exchange is achieved between the insulating liquid 30 and the conductive component 90, thereby dissipating heat and cooling the conductive component 90 and reducing the possibility of the conductive component 90 overheating.

[0091] In one example, insulating liquid 30 immerses all conductive parts 90.

[0092] In one example, the conductive element 90 may include, but is not limited to, a wire harness or a copper busbar.

[0093] In one example, connector 80 may include, but is not limited to, an aviation connector.

[0094] In one example, connector 80 is disposed on the first peripheral wall 22, and a portion of conductive element 90 is located within the second gap 102.

[0095] In one feasible approach, see Figure 9 and Figure 10 As shown, the second housing 40 includes a third receiving cavity 402 having a third opening 4021. The second receiving cavity 401 and the third receiving cavity 402 are isolated from each other. The third opening 4021 is located within the first receiving cavity 201 and is submerged by insulating liquid 30. The third receiving cavity 402 is configured to receive an electronic device 100 connected to the cell assembly 50.

[0096] The second receiving cavity 401 and the third receiving cavity 402 are each independently configured and not connected to each other. The battery cell assembly 50 is isolated from the electronic devices 100 in the third receiving cavity 402. When the electronic devices 100 in the third receiving cavity 402 are damaged or fail, the impact on the safety of the battery cell assembly 50 is small, which helps to improve the safety of the battery cell assembly 50.

[0097] The insulating liquid 30 immerses at least a portion of the electronic device 100, and the insulating liquid 30 dissipates heat and cools the electronic device 100, reducing the possibility of the electronic device 100 malfunctioning due to excessive temperature, and improving the safety of the battery cell assembly 50.

[0098] The second housing 40 can protect the electronic device 100 inside the third receiving cavity 402, reducing the possibility of damage or failure of the electronic device 100.

[0099] In one example, electronic device 100 includes, but is not limited to, a high-voltage box and a circuit board.

[0100] This application provides an energy storage device, which includes the battery pack 10 of the above embodiments.

[0101] Energy storage devices are used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery pack characterized by comprising: include: The first housing includes a first receiving cavity having a first opening; An insulating liquid is disposed within the first receiving cavity, wherein the liquid level of the insulating liquid is lower than the first opening; A second housing, connected to the first housing, the second housing including a second receiving cavity having a second opening, at least a portion of the second housing located within the first receiving cavity, the second opening located within the first receiving cavity and the insulating liquid immersing the second opening; A battery cell assembly, at least a portion of which is located within the second receiving cavity.

2. The battery pack according to claim 1, characterized in that, The first housing includes a first bottom wall and a first peripheral wall, the first bottom wall and the first peripheral wall being connected to form the first receiving cavity; The second housing includes an extension wall, a second bottom wall, and a second peripheral wall. The second bottom wall and the second peripheral wall are connected to form the second receiving cavity. The extension wall connects the first peripheral wall and the second peripheral wall. The second housing closes the first opening.

3. The battery pack according to claim 2, characterized in that, The second opening is disposed facing the first bottom wall, and there is a first gap between the first bottom wall and the cell assembly, the insulating liquid filling the first gap; There is a second gap communicating with the first gap between the first peripheral wall and the second peripheral wall, and the insulating liquid fills at least a portion of the second gap.

4. The battery pack according to claim 3, characterized in that, The battery pack includes an exhaust section configured to discharge gases generated by the cell assembly to the outside of the battery pack. The first gap and the second gap are configured to discharge the gas generated by the battery cell assembly.

5. The battery pack according to claim 4, characterized in that, The first peripheral wall is provided with an exhaust section, and the liquid level of the insulating liquid is lower than the exhaust section.

6. The battery pack according to any one of claims 3 to 5, characterized in that, End plates are respectively provided on opposite sides of the battery cell assembly, and the end plates are connected and fixed to the first bottom wall; The end plate has at least a third gap between itself and the first bottom wall, and the insulating liquid fills the third gap.

7. The battery pack according to claim 6, characterized in that, The battery cell assembly includes a plurality of battery cells arranged in a first direction. The battery cell has a pressure relief section, which is spaced apart from the first bottom wall. Along the first direction, at least a portion of the projection of the pressure relief section is located within the projection of the end plate. The insulating liquid wets at least a portion of the pressure relief section.

8. The battery pack according to any one of claims 1 to 7, characterized in that, The battery pack includes a connector and a conductive element. The connector is disposed in the first housing, and the conductive element connects the cell assembly and the connector. The insulating liquid immerses at least a portion of the conductive element.

9. The battery pack according to any one of claims 1 to 8, characterized in that, The second housing includes a third receiving cavity having a third opening, the second receiving cavity and the third receiving cavity being isolated from each other, the third opening being located within the first receiving cavity and the insulating liquid immersing the third opening, the third receiving cavity being configured to receive electronic devices connected to the cell assembly.

10. An energy storage device, characterized in that, Includes the battery pack as described in any one of claims 1 to 9.

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