Battery pack

Abstract

The utility model relates to the technical field of thermal management, in particular to a battery pack. The battery pack comprises a box body, a heat exchange medium and a plurality of battery cells; the box body comprises a frame, a panel, a reinforcing plate and a bottom plate; a closed inner cavity is defined by the frame, the panel and the bottom plate. The reinforcing plate is arranged between the panel and the bottom plate; a heat exchange area is defined by the panel, the inner wall of the frame and the reinforcing plate, and a protection area is defined by the reinforcing plate, the inner wall of the frame and the bottom plate; a plurality of liquid distribution holes are formed in the reinforcing plate; the heat exchange medium is arranged in the heat exchange area and the protection area; the panel is provided with a through hole, the lower portion of the battery cell is inserted into the heat exchange area through the through hole and abuts against the reinforcing plate, and the upper portion of the battery cell is located above the box body. Therefore, the structural strength can be enhanced, the protection of the bottom of the battery cell is enhanced, the protection and the current sharing need are considered, the space multiplexing is realized, the sealing is reliable, and the maintenance convenience is provided.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal management, and more specifically, to a battery pack. Background Art

[0002] The battery pack is a core component of new energy vehicles. With the competition in performance such as safety, ultra-fast charging, long endurance, and rapid acceleration, and the continuous improvement of application modes such as CTB and CTC, more and more and higher requirements are put forward in terms of the functional performance of the battery pack, such as density, temperature, stiffness, strength, safety, economy, reliability, and maintainability. All of these can only be met by the technological innovation of the battery pack.

[0003] The mainstream technology for the thermal management of existing battery packs is liquid-cooled plate heat exchange. Due to the limited heat exchange area and heat transfer coefficient, the existing thermal management technology still has difficulty meeting the requirements of high-rate charging and discharging, cannot effectively prevent thermal runaway, and is even more difficult to cope with the spread of thermal runaway. In application modes such as CTB and CTC, the battery pack is an integral part of the vehicle body structure, and high requirements are imposed on aspects such as structural strength, torsional stiffness, and collision resistance. The battery pack also needs to provide comprehensive protection for the battery cells to avoid thermal runaway after mechanical damage.

[0004] In order to meet the requirement of lightweight, only materials such as structural adhesives and polyurethanes can be used to bond the liquid-cooled plate and the battery cells together as structural components. Although this can obtain certain strength and protection, it sacrifices maintainability. A problem with one battery cell will cause the entire battery pack to be scrapped. Although the manufacturing cost is reduced, the maintenance cost and insurance cost are increased. In addition, insufficient protection at the bottom of the battery pack is likely to cause damage to the battery cells and trigger vehicle spontaneous combustion.

[0005] Semi-immersed batteries can expand the heat exchange area and increase the heat transfer coefficient, and can effectively block the spread of thermal runaway. However, the large-sized battery pack makes it difficult to achieve uniform flow of the heat exchange medium. The existing uniform flow design is prone to too low local flow velocity, resulting in inconsistent battery cell performance and even thermal runaway; the problem of heat exchange medium leakage has not been completely solved, and it is also difficult to meet the high requirements of application methods such as CTP, CTB, and CTC in terms of structural strength; if a heat exchange medium with good electrical insulation performance is used, the price is high, and there is a risk of electric leakage when using cheap ethylene glycol aqueous solution.

[0006] The above problems limit the popularization and application of semi-immersed power batteries. Summary of the Utility Model

[0007] The objectives of the present utility model include, for example, providing a battery pack that can enhance structural strength, strengthen the protection of the bottom of the battery cells, achieve space multiplexing for both protection and uniform flow, provide a reliable sealing method, and provide maintenance convenience.

[0008] The embodiments of the present utility model can be implemented as follows:

[0009] In a first aspect, the present utility model provides a battery pack, comprising:

[0010] a box body, a heat exchange medium, and a plurality of battery cells;

[0011] The box body includes a frame, a panel, a reinforcing plate, and a bottom plate; the frame, the panel, and the bottom plate enclose a sealed inner cavity;

[0012] The reinforcing plate is disposed between the panel and the bottom plate; the panel, the inner wall of the frame, and the reinforcing plate enclose a heat exchange area, and the reinforcing plate, the inner wall of the frame, and the bottom plate enclose a protection area; a plurality of liquid distribution holes are provided on the reinforcing plate; the heat exchange medium is disposed in the heat exchange area and the protection area;

[0013] A through hole is formed on the panel, and the lower part of the battery cell is inserted into the heat exchange area through the through hole and abuts against the reinforcing plate, and the upper part of the battery cell is located above the box body.

[0014] In an optional embodiment, a plurality of reinforcing columns are further included, and the reinforcing columns are all located between the panel and the reinforcing plate; along the height direction of the reinforcing column, one end of each reinforcing column is connected to the panel, and the other end is connected to the reinforcing plate.

[0015] In an optional embodiment, a flow channel for the liquid-phase heat exchange medium to pass through is formed between the reinforcing column and the outer wall of the adjacent battery cell.

[0016] In an optional embodiment, a plurality of through holes are formed on the panel; along the width direction of the panel, the plurality of through holes form a plurality of parallel through hole groups; a distance is maintained between adjacent through hole groups, and the through holes in each through hole group are all kept at intervals; along the width direction of the panel, the through holes in one through hole group are located between two adjacent through holes in the adjacent other through hole group; the reinforcing column is located between adjacent through holes.

[0017] In an optional embodiment, a plurality of through holes are formed on the panel; along the width direction of the panel, the plurality of through holes form a plurality of parallel through hole groups; in each through hole group, adjacent through holes are arranged in parallel; and along the width direction of the panel, the through holes in adjacent through hole groups are arranged in a facing manner; the reinforcing column is located between adjacent through holes.

[0018] In an optional embodiment, a downward first protrusion is provided at the bottom of the reinforcing plate, and an upward second protrusion is provided at the top of the bottom plate; the first protrusion and the second protrusion can abut against each other.

[0019] In an alternative embodiment, a seal is further included; the seal is disposed between the battery cell and the through hole; the outer side of the seal fits the through hole, and the inner side of the seal fits the outer wall of the battery cell.

[0020] In an alternative embodiment, a circulation pump is further included. The box body is provided with a liquid inlet and a liquid outlet. The liquid inlet is connected to the inlet of the circulation pump, and the liquid outlet is connected to the outlet of the circulation pump.

[0021] The liquid inlet is located in the heat exchange area or the protection area, and the liquid outlet is located in the heat exchange area or the protection area.

[0022] In an alternative embodiment, along the circumferential direction of the frame, a ring-shaped boss that is connected end to end is provided on the inner wall of the frame; the top of the boss forms an upper boss with the inner wall of the frame, and the panel is disposed on the upper boss; the bottom of the boss forms a lower boss with the inner wall of the frame, and the reinforcing plate abuts against the lower boss.

[0023] In an alternative embodiment, above the immersion liquid level of the heat exchange medium in the liquid phase in the heat exchange area is a non-immersion area; the non-immersion area is configured to be able to accommodate the heat exchange medium in the gas phase; at least part of the battery cell is immersed in the liquid-phase heat exchange medium.

[0024] The battery pack further includes a negative pressure device, and the negative pressure device is communicated with the non-immersion area so that the air pressure in the non-immersion area can be lower than the ambient atmospheric pressure.

[0025] At least part of the heat exchange medium is configured to be able to evaporate into steam in the inner cavity, and the steam quickly moves to the low-temperature place under the drive of the pressure difference and condenses to release heat, so as to realize the cooling of the battery cell.

[0026] The beneficial effects of the embodiments of the present invention include, for example:

[0027] The battery pack of the present solution includes a box body, a heat exchange medium and a plurality of battery cells. The frame, the panel and the bottom plate of the box body enclose a closed inner cavity; and a reinforcing plate is disposed between the panel and the bottom plate, such as dividing the inner cavity into a heat exchange area above the reinforcing plate and a protection area below the reinforcing plate, and the heat exchange area and the protection area are communicated through the liquid distribution holes on the reinforcing plate. The heat exchange medium in the heat exchange area can be used for immersing and cooling the battery, while the protection area is beneficial to evenly distribute the heat exchange medium and improve the efficiency of the circulation and flow of the heat exchange medium. The reinforcing plate of such a battery pack integrates the multiple requirements of distributing the heat exchange medium, storing liquid and enhancing the bottom protection, saves materials and space, and the heat exchange medium in the protection area can play a role in absorbing impact energy when the bottom is impacted, and together with the bottom plate, provides better protection for the battery cell; the negative pressure can generate a phase change to enhance the temperature equalization effect and prevent the leakage of the heat exchange medium. Description of the Drawings

[0028] To more clearly illustrate the technical solutions of the embodiments of the present utility model, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following accompanying drawings only show certain embodiments of the present utility model and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related accompanying drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a schematic structural diagram of the battery pack according to Embodiment 1 of the present utility model;

[0030] Figure 2 It is an assembly schematic diagram of the battery pack according to Embodiment 1 of the present utility model;

[0031] Figure 3a It is a schematic structural diagram of the battery pack according to Embodiment 1 of the present utility model from one perspective;

[0032] Figure 3b It is along Figure 3a The cross-sectional view in the A-A direction in;

[0033] Figure 4 It is a schematic structural diagram of the battery pack according to Embodiment 1 of the present utility model from another perspective;

[0034] Figure 5 It is a partially enlarged schematic diagram of the battery pack according to Embodiment 1 of the present utility model;

[0035] Figure 6a It is a schematic structural diagram of the reinforcing plate of the battery pack according to Embodiment 1 of the present utility model;

[0036] Figure 6b It is a schematic structural diagram of the reinforcing plate of the battery pack according to Embodiment 1 of the present utility model from another perspective;

[0037] Figure 7a It is a schematic structural diagram of the bottom plate of the battery pack according to Embodiment 1 of the present utility model;

[0038] Figure 7b It is a schematic structural diagram of the bottom plate of the battery pack according to Embodiment 1 of the present utility model from another perspective;

[0039] Figure 8 Another perspective assembly schematic diagram of the battery pack according to Embodiment 1 of the present utility model;

[0040] Figure 9 It is a schematic structural diagram of the cell arrangement of the battery pack according to Embodiment 2 of the present utility model;

[0041] Figure 10 It is a schematic structural diagram of the cell arrangement of the battery pack according to Embodiment 2 of the present utility model from another perspective;

[0042] Figure 11 It is a partially enlarged schematic view of the battery pack according to the second embodiment of the present utility model;

[0043] Figure 12 It is a partially enlarged schematic view of another perspective of the battery pack according to the second embodiment of the present utility model;

[0044] Figure 13 It is a structural schematic view of the reinforcing plate of the battery pack according to the second embodiment of the present utility model;

[0045] Figure 14 It is a structural schematic view of the cooperation between the bottom plate and the battery cells of the battery pack according to the second embodiment of the present utility model.

[0046] Icon: 1 - battery cell; 101 - first electrode; 102 - second electrode; 2 - seal; 30 - box body; 301 - air extraction port; 302 - liquid outlet; 303 - liquid inlet; 304 - total exhaust port; 310 - panel; 311 - through hole; 312 - compression screw hole; 313 - compression screw; 314 - compression gasket; 320 - frame; 321 - boss; 322 - transfer cavity; 330 - reinforcing plate; 331 - liquid distribution hole; 340 - bottom plate; 350 - reinforcing column; 400 - flow channel; 500 - through hole group; 610 - first protrusion; 620 - second protrusion; 630 - support protrusion. Detailed implementation manners

[0047] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Usually, the components of the embodiments of the present utility model described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present utility model provided in the accompanying drawings is not intended to limit the scope of the present utility model to be protected, but merely represents the selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts fall within the scope of protection of the present utility model.

[0049] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0050] In the description of the present utility model, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present utility model is usually placed during use, it is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0051] In addition, if terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0052] It should be noted that, without conflict, the features in the embodiments of the present utility model can be combined with each other.

[0053] Embodiment 1

[0054] Please refer to Figure 1 , this embodiment provides a battery pack, including Please refer to Figure 1 , this embodiment provides a battery pack, including a box body 30, a heat exchange medium, and a plurality of battery cells 1;

[0055] The box body 30 includes a frame 320, a panel 310, a reinforcing plate 330, and a bottom plate 340; the frame 320, the panel 310, and the bottom plate 340 enclose to form a sealed inner cavity;

[0056] The reinforcing plate 330 is disposed between the panel 310 and the bottom plate 340; the panel 310, the inner wall of the frame 320, and the reinforcing plate 330 enclose to form a heat exchange area, and the reinforcing plate 330, the inner wall of the frame 320, and the bottom plate 340 enclose to form a protection area; a plurality of liquid distribution holes 331 are provided on the reinforcing plate 330; the heat exchange medium is disposed in the heat exchange area and the protection area;

[0057] A through hole 311 is formed on the panel 310, and the lower part of the battery cell 1 is inserted into the heat exchange area through the through hole 311 and abuts against the reinforcing plate 330, and the upper part of the battery cell 1 is located above the box body 30.

[0058] The frame 320, the panel 310, and the bottom plate 340 of the battery pack in this solution enclose a sealed inner cavity; and the reinforcing plate 330 is disposed between the panel 310 and the bottom plate 340, dividing the inner cavity into a heat exchange area above the reinforcing plate 330 and a protection area below the reinforcing plate 330, and the heat exchange area and the protection area are connected through the liquid distribution holes 331 on the reinforcing plate 330. The heat exchange medium in the heat exchange area can be used for immersion cooling of the battery, and the protection area is conducive to evenly distributing the heat exchange medium and improving the efficiency of the circulation and flow of the heat exchange medium. The lower part of the battery cell 1 is inserted into the heat exchange area through the through hole 311 and contacts the reinforcing plate 330; a protection area is formed between the reinforcing plate 330 and the bottom plate 340, and the protection area communicates with the liquid outlet 302 and / or the liquid inlet 303; a plurality of liquid distribution holes 331 are provided on the reinforcing plate 330 for the heat exchange medium to flow orderly between the heat exchange area and the protection area. The reinforcing plate 330 integrates multiple requirements of distributing the heat exchange medium, storing liquid, and enhancing bottom protection, saving materials and space, and the heat exchange medium in the protection area can absorb the impact energy when being impacted at the bottom, providing better protection for the battery cell 1 together with the bottom plate 340.

[0059] It should be noted that the battery cell 1 includes a first electrode 101 and a second electrode 102 located above the box body 30. The box body 30 is provided with a liquid inlet 303 and a liquid outlet 302 communicating with the inner cavity. In an alternative embodiment, the battery pack further includes a circulation pump. The box body 30 is provided with a liquid inlet 303 and a liquid outlet 302. The liquid inlet 303 is connected to the inlet of the circulation pump, and the liquid outlet 302 is connected to the outlet of the circulation pump; the liquid inlet 303 is located in the heat exchange area or the protection area, and the liquid outlet 302 is located in the heat exchange area or the protection area.

[0060] From Figure 1 、 Figure 2 、 Figure 3a and Figure 3b It can also be seen that in an alternative embodiment, along the circumferential direction of the frame 320, the inner wall of the frame 320 has a ring-shaped boss 321 connected end to end; the top of the boss 321 and the inner wall of the frame 320 form an upper boss, and the panel 310 is disposed on the upper boss; the bottom of the boss 321 and the inner wall of the frame 320 form a lower boss, and the reinforcing plate 330 abuts against the lower boss. The boss 321 can enhance the overall strength of the battery pack on the one hand and serve as the installation structure for the panel 310 and the reinforcing plate 330 on the other hand.

[0061] Optionally, the panel 310 can be fixed on the upper boss by means of integral casting, welding, flange surface screw assembly, etc., and the reinforcing plate 330 can be fixed on the lower boss by means of integral casting, welding, flange surface screw assembly, etc.

[0062] Further, in an alternative embodiment, the battery pack further includes a plurality of reinforcing columns 350, and the reinforcing columns 350 are all located between the panel 310 and the reinforcing plate 330; along the height direction of the reinforcing column 350, one end of each reinforcing column 350 is connected to the panel 310, and the other end is connected to the reinforcing plate 330. The reinforcing columns 350 can further increase the strength and stiffness of the battery pack. Specifically, reinforcing columns 350 are provided between the panel 310 and the reinforcing plate 330, the number of the reinforcing columns 350 is not less than the number of the battery cells 1, one end of each reinforcing column 350 is connected to the panel 310, and the other end is connected to the reinforcing plate 330. The reinforcing columns 350 can also adjust the shape and installation position according to the need to control the flow direction and flow rate of the heat exchange medium. Combining with the arrangement of the liquid distribution holes 331 on the reinforcing plate 330, a good flow equalization effect can be obtained. Since the reinforcing plate 330 does not have a high sealing requirement, a large number of screw holes will not have a great influence on the flow direction of the heat exchange medium, so the reinforcing plate 330 and the reinforcing columns 350 can be directly connected by screws.

[0063] In an alternative embodiment, the battery pack further includes a seal 2; the seal 2 is arranged between the battery cell 1 and the through hole 311; the outer side of the seal 2 is attached to the through hole 311, and the inner side of the seal 2 is attached to the outer wall of the battery cell 1.

[0064] Further, in this embodiment of the present invention, the diameter of the upper part of the through hole 311 is larger than the diameter of the lower part of the through hole 311; the wall thickness of the lower part of the seal 2 is greater than the average gap between the battery cell 1 and the through hole 311.

[0065] To prevent the heat exchange medium from leaking through the through hole 311, the panel 310 should be made of a thick material or formed by stamping a plate, and it is necessary to ensure that the depth of the through hole 311 is greater than 5 mm, and the upper diameter of the through hole 311 is larger than the lower diameter; a seal 2 is also provided between the battery cell 1 and the through hole 311. The outer shape of the seal 2 fits the through hole 311, and the inner shape fits the outer shape of the battery cell 1. The seal 2 has elasticity, and the wall thickness of its lower part is slightly greater than the average gap between the battery cell 1 and the through hole 311 in the natural state, ensuring that when the battery cell 1 is inserted into the through hole 311, the seal 2 can be pressed to deform to prevent leakage.

[0066] In this embodiment of the present invention, the height of the seal 2 is less than 80% of the depth of the through hole 311; the seal 2 can be flush with the top surface of the through hole 311, and there is a gap between the bottom of the seal 2 and the bottom surface of the through hole 311; the liquid level of the liquid-phase heat exchange medium is lower than the bottom of the through hole 311, so as to form an air cushion around the battery cell 1 and the through hole 311.

[0067] To prevent the heat exchange medium from shaking and repeatedly impacting the seal during the movement state, resulting in leakage, by making the depth of the seal 2 less than 80% of the depth of the through hole 311, the static immersion liquid level of the heat exchange medium is lower than the bottom of the through hole 311, and an air cushion is formed between the battery cell 1 and the through hole 311, the impact intensity of the heat exchange medium can be reduced.

[0068] In this embodiment of the present utility model, the battery pack further includes a compression screw 313 and a compression gasket 314. The panel 310 is provided with compression screw holes 312 corresponding to the battery cells 1; the compression screw holes 312 pass through the compression gasket 314 and are provided in the compression screw holes 312; the compression screw 313 is configured to press the battery cell 1 against the reinforcement plate 330 through the compression gasket 314, so as to press the battery cell 1 and the seal 2 against the through hole 311.

[0069] In this way, the battery cell 1 is pressed against the reinforcement plate 330 by the compression screw 313 and the compression gasket 314, and the seal 2 is pressed against the through hole 311 by the battery cell 1, so that the battery cell 1, the panel 310, the frame 320, the reinforcement column 350, and the reinforcement plate 330 form a composite structural member with high strength and high torsional stiffness. The seal 2 not only plays a sealing role, but also plays a role in buffering and absorbing impact energy, making the battery pack rigid and flexible and having excellent impact resistance.

[0070] From Figure 3a and Figure 3b it can also be seen that in an alternative embodiment, the panel 310 is provided with a plurality of through holes 311; along the width direction of the panel 310, the plurality of through holes 311 form a plurality of through hole groups 500 arranged in parallel; there is a spacing between adjacent through hole groups 500, and the through holes 311 of each through hole group 500 are kept at intervals; along the width direction of the panel 310, the through holes 311 in one through hole group 500 are located between two adjacent through holes 311 in the adjacent other through hole group 500; the reinforcement column 350 is located between adjacent through holes 311.

[0071] In this embodiment, the through holes 311 are densely arranged in a triangular shape, and each through hole 311 surrounds three compression screw holes 312. The cross section of the through hole 311 is larger at the top and smaller at the bottom. The seal 2 is a silicone rubber ring. When the battery cell 1 enters, it will stretch the seal 2 to make it thinner. When the vacuum is pumped after the assembly is completed, the seal 2 will rebound and become thicker under the push of negative pressure, more thoroughly closing the space between the battery cell 1 and the through hole 311.

[0072] As Figure 4 shown, in an alternative embodiment, the bottom of the reinforcement plate 330 is provided with a downward first protrusion 610, and the top of the bottom plate 340 is provided with an upward second protrusion 620; the first protrusion 610 and the second protrusion 620 can abut against each other. The first protrusion 610 and the second protrusion 620 cooperate to increase the stability and reliability between the reinforcement plate 330 and the bottom plate 340.

[0073] Further, the reinforcing plate 330 is provided with a double-sided protrusion, where the first protrusion 610 faces the bottom plate 340, and the bottom plate 340 is also provided with a second protrusion 620 whose position corresponds to that of the first protrusion 610 and whose height sum can ensure close contact. The protrusion structures (the first protrusion 610 and the second protrusion 620) not only increase the strength respectively but also form mutual support, providing a larger deformation space and better absorption effect when the bottom is impacted. Usually, the liquid inlet 303 and the liquid outlet 302 are arranged on the frame 320. To reduce the space occupation, the height of the protection area needs to be compressed. The liquid outlet 302 can be arranged at a height corresponding to the heat exchange area and is connected to the protection area through the downward transfer cavity 322. The liquid inlet 303 can be directly connected to the heat exchange area.

[0074] As Figure 5 shown, in an alternative embodiment, a flow channel 400 for the liquid-phase heat exchange medium to pass through is formed between the reinforcing column 350 and the outer wall of the adjacent battery cell 1. The shape of the reinforcing column 350 is designed according to the need of guiding the liquid flow, and a screw hole is provided in the center for fastening the reinforcing plate 330. The reinforcing column 350 guides the liquid flow to flow through all surfaces of the battery cell 1 by setting a resistance on the liquid flow shortcut, and the effect is as shown in the partial enlarged view Figure 5 shown, where the thick black line represents the flow path of the liquid flow.

[0075] Figure 6a 、 Figure 6b shows a schematic structural view of the reinforcing plate 330. The reinforcing plate 330 is formed by stamping a steel plate. The upward protrusion of the reinforcing plate 330 is used to position the battery cell 1, and the downward first protrusion 610 of the reinforcing plate 330 is used to drain liquid and release gas when the thermal runaway explosion-proof valve is opened.

[0076] Figure 7a 、 Figure 7b shows a schematic structural view of the bottom plate 340. The upward second protrusion 620 of the bottom plate 340 is used to contact the downward first protrusion 610 of the reinforcing plate 330 to form an elastic support, and the downward reinforcing protrusion 630 of the bottom plate 340 is used to enhance the strength of the single-board structure and increase the deformation space.

[0077] As Figure 4 、 Figure 6a 、 Figure 6b 、 Figure 7a and Figure 7b , in the present embodiment of the present invention, the top of the bottom plate 340 is provided with a second protrusion 620 for support extending towards the reinforcing plate 330, and the second protrusion 620 abuts against the reinforcing plate 330; the bottom of the bottom plate 340 is provided with a reinforcing protrusion 630 extending away from the reinforcing plate 330, and the reinforcing protrusion 630 is used to enhance the strength of the single-board structure and increase the deformation space. In the present embodiment of the present invention, the support protrusion 630 abuts against the bottom of the pressure relief groove.

[0078] Optionally, a partition plate is provided between the reinforcing plate 330 and the bottom plate 340 to divide the protection area into a liquid inlet area and a liquid outlet area. The liquid inlet area communicates with the liquid inlet 303, and the liquid outlet area communicates with the liquid outlet 302. The reinforcing plate 330 is provided with liquid distribution holes 331 in both the liquid inlet area and the liquid outlet area. The liquid inlet 303 and the liquid outlet 302 can both communicate with the liquid inlet area and the liquid outlet area through the downward transfer cavity 322, and then the inlet and outlet positions of the liquid in the heat exchange area can be set through the liquid distribution holes 331 on the reinforcing plate 330.

[0079] To further increase the structural strength, reduce the assembly complexity, improve the assembly accuracy and avoid leakage, it is a preferred solution that the panel 310, the reinforcing column 350 and the frame 320 are integrally die-cast from aluminum alloy. The reinforcing column 350 is provided with screw holes, and the reinforcing plate 330 can be directly fixed to the reinforcing column 350 and the frame 320 with screws.

[0080] Since the outer shell of the battery cell 1 is in direct contact with the heat exchange medium, if a heat exchange medium with insufficient insulation performance such as pure water or ethylene glycol aqueous solution is used, the outer shell of the battery cell 1 must ensure insulation, and at the same time, the thermal conductivity cannot drop too much. Therefore, methods such as anodic oxidation and micro-arc oxidation are required to form a dense chemical film with good insulation performance on the outer surface of the outer shell of the battery cell 1.

[0081] To avoid vibration and wear of the insulation layer of the outer shell of the battery cell 1, an elastic rubber ring is provided at the bottom edge of the outer shell of the battery cell 1 in contact with the reinforcing plate 330. In addition to reducing wear, it also enhances the stability of the assembly and the elasticity when dealing with impacts.

[0082] Please refer to Figure 8 , Figure 8 , which shows that the battery pack can be directly connected to the vehicle frame, and the bottom plate 340 can be directly docked above the battery pack. A thermal insulation layer and an outer protection plate are usually required below the battery pack.

[0083] In an alternative embodiment, the non-immersion area is above the immersion liquid level of the heat exchange medium in the liquid phase in the heat exchange area; the non-immersion area is configured to be able to accommodate the gaseous heat exchange medium; at least part of the battery cell 1 is immersed in the liquid-phase heat exchange medium;

[0084] The battery pack further includes a negative pressure device, which communicates with the non-immersion area so that the air pressure in the non-immersion area can be lower than the ambient atmospheric pressure;

[0085] At least part of the heat exchange medium is configured to be able to evaporate into steam in the inner cavity, and the steam quickly moves to the lower temperature under the drive of the pressure difference and condenses to release heat to achieve the cooling of the battery cell 1.

[0086] Although the present utility model has taken measures to ensure the uniform flow of the heat exchange medium and also taken multiple measures to prevent the leakage of the heat exchange medium, in order to further improve the heat exchange performance and further prevent leakage, the box body 30 is provided with an air extraction port 301. The air extraction port 301 is internally connected to the top inside the box body 30 and externally connected to a vacuum device. By evacuating the air, the box body 30 presents a negative pressure state, allowing the heat exchange medium to boil at a higher temperature, quickly dispersing the heat throughout the battery pack, and then releasing the heat to the outside through the circulation of the heat exchange medium. If there is a leak in the box body 30, due to the negative pressure, only external air can enter the box body 30, and the heat exchange medium will not leak out to damage the battery pack. The air that leaks into the box body 30 can be continuously discharged by the vacuum device.

[0087] Embodiment 2

[0088] Please refer to Figure 9 、 Figure 10 In an alternative embodiment, a plurality of through holes 311 are formed in the panel 310; along the width direction of the panel 310, the plurality of through holes 311 form a plurality of through hole groups 500 arranged in parallel; in each through hole group 500, adjacent through holes 311 are arranged in parallel; and along the width direction of the panel 310, the through holes 311 in adjacent through hole groups 500 are arranged opposite to each other; the reinforcing columns 350 are located between adjacent through holes 311.

[0089] Optionally, the battery cell 1 is a square battery cell 1, which is arranged in a horizontal and vertical combination, taking into account the higher anti-collision ability requirements on the side and the requirements for large-size longitudinal strengthening. Referring to a battery pack of the same size with 216 battery cells 1 of the same specification, immersion cooling can make the spacing between the battery cells 1 smaller and the installation density higher. In the figure, the positions of 2 battery cells 1 are left empty at the bottom for the transfer of the heat exchange medium in and out and the installation of the air extraction and exhaust ports. The main body of the battery pack structure is integrally cast with the panel 310, the frame 320, and the reinforcing columns 350, ensuring accuracy and strength and reducing the complexity of assembly. The main body of the battery pack structure is integrally cast with the panel 310, the frame 320, and the reinforcing columns 350, ensuring accuracy and strength and reducing the complexity of assembly.

[0090] From Figure 11 it can be seen that the through holes 311 of the battery cells 1 in different directions, the flow guiding columns of different shapes, the liquid inlet 303 and the transfer cavity 322, as well as the bosses for installing the reinforcing plate 330 and the outer frame of the installation bottom plate 340. From Figure 12 it can be seen the partial view after placing the reinforcing plate 330. The reinforcing plate 330 of this embodiment is provided with liquid distribution holes 331 and double-sided protrusions.

[0091] Figure 13It is a schematic structural diagram of the reinforcement plate 330 of this embodiment, which is provided with an opening for docking the inlet and outlet liquid transfer cavity 322, and is respectively provided with a liquid inlet distribution hole 331 and a liquid outlet distribution port on both sides. The heat exchange medium flows left and right, and flows through each immersed surface of the battery cell 1 under the guidance of the reinforcement column 350.

[0092] Figure 14 It is a schematic structural diagram of the bottom plate 340 of this embodiment, which is provided with a double-sided protrusion, and is provided with two partition plates in the middle. The partition plates press the reinforcement plate 330, dividing the protection area into a liquid inlet area, a partition area, and a liquid outlet area.

[0093] In summary, the embodiment of the present utility model provides a battery pack, which has at least the following advantages:

[0094] The structural parts of the battery in this solution and the battery cell 1 support and combine with each other to form a rigid-flexible integrated whole, with strength and torsional stiffness superior to various existing technical solutions, fully meeting the application requirements of CTP, CTB, and CTC. In particular, the protection capabilities on the side and bottom are strengthened, creating a safe and reliable working environment for the battery cell 1, and minimizing the possibility of fire and explosion of the battery pack caused by external intrusion.

[0095] High space utilization and less material consumption, bottom protection and liquid storage and diversion, eliminating the liquid collecting pipes and space on both sides, and direct immersion cooling eliminating the liquid cooling plate, the battery cells 1 can be arranged more densely, and the number of battery cells 1 that can be installed in a battery pack of the same volume is increased by at least 10%.

[0096] The liquid distribution holes 331 on the reinforcement plate 330 can flexibly distribute the position and quantity of the heat exchange medium in and out, the reinforcement column 350 can guide the flow path of the heat exchange medium, and combined with the smaller spacing between the battery cells 1, the flow direction and flow rate of the heat exchange medium can be evenly controlled. Coupled with the phase change and temperature equalization under negative pressure, it provides a uniform and stable temperature environment for the battery cell 1, and can meet the heat dissipation performance requirements of battery supercharging and vehicle rapid acceleration.

[0097] There are only elastic constraints on the upper and bottom parts of the periphery of the battery cell 1, and the middle part that may expand has no constraints at all, providing an adaptive space for the expansion of the battery cell 1.

[0098] Large inclined plane sealing and air cushion buffering, combined with negative pressure, the leakage risk is completely controllable. After eliminating the risk of liquid leakage causing electric leakage, the battery shell is insulated, and the electric leakage risk is basically eliminated.

[0099] Higher reliability and maintainability, all assemblies of the battery pack are visible, verifiable, and repeatable, and are all mature and reliable assembly processes, facilitating robot assembly. Any battery cell 1 can be simply replaced without using destructive means, greatly reducing the maintenance difficulty and maintenance cost.

[0100] The safety guarantee is more comprehensive. When abnormal conditions such as short circuit occur in the battery cell 1, the heat exchange medium in full contact can quickly spread the heat through boiling to the entire battery pack to share, thereby suppressing the early thermal runaway and preventing the situation from deteriorating, leaving enough warning time. After the thermal runaway of a single battery cell 1, the surrounding temperature is controlled below the boiling temperature of the heat exchange medium, which will not cause the thermal runaway of the surrounding battery cells 1 and can well prevent the spread of thermal runaway. The exhaust valve can timely discharge the generated gas to prevent problems before they become serious, and the explosion-proof valve at the bottom can quickly drain the liquid to reduce the quantity of combustible gas discharged after the thermal runaway occurs. A small amount of non-condensable gas is discharged to a safe position through the total exhaust port 304 to prevent the vehicle from catching fire and exploding. Although the thermal runaway of the battery cell 1 may not be completely eliminated, the utility model can reduce the loss caused by the thermal runaway of the battery cell 1 from the vehicle level to the battery pack level, or even to the battery cell 1 level. More importantly, it guarantees the safety of the driver and passengers.

[0101] The above is only the specific implementation manner of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the utility model should be covered by the protection scope of the utility model. Therefore, the protection scope of the utility model shall be subject to the protection scope of the claims.

Claims

1. A battery pack, characterized in that, Comprising: A box body (30), a heat exchange medium, and a plurality of battery cells (1); The box body (30) includes a frame (320), a panel (310), a reinforcing plate (330), and a bottom plate (340); the frame (320), the panel (310), and the bottom plate (340) enclose to form a sealed inner cavity; The reinforcing plate (330) is disposed between the panel (310) and the bottom plate (340); the panel (310), the inner wall of the frame (320), and the reinforcing plate (330) enclose to form a heat exchange area, and the reinforcing plate (330), the inner wall of the frame (320), and the bottom plate (340) enclose to form a protection area; a plurality of liquid distribution holes (331) are provided on the reinforcing plate (330); the heat exchange medium is disposed in the heat exchange area and the protection area; A through hole (311) is formed on the panel (310), and the lower part of the battery cell (1) is inserted into the heat exchange area through the through hole (311) and abuts against the reinforcing plate (330), and the upper part of the battery cell (1) is located above the box body (30).

2. The battery pack according to claim 1, wherein: It further includes a plurality of reinforcing columns (350), and the reinforcing columns (350) are all located between the panel (310) and the reinforcing plate (330); along the height direction of the reinforcing column (350), one end of each reinforcing column (350) is connected to the panel (310), and the other end is connected to the reinforcing plate (330).

3. The battery pack according to claim 2, wherein: A flow channel (400) for the liquid-phase heat exchange medium to pass through is formed between the reinforcing column (350) and the outer wall of the adjacent battery cell (1).

4. The battery pack according to claim 2, wherein: A plurality of through holes (311) are formed on the panel (310); along the width direction of the panel (310), the plurality of through holes (311) form a plurality of parallelly arranged through hole groups (500); a gap is maintained between adjacent through hole groups (500), and the through holes (311) of each through hole group (500) are all maintained with a gap; along the width direction of the panel (310), the through holes (311) in one through hole group (500) are located between two adjacent through holes (311) in the adjacent other through hole group (500); the reinforcing column (350) is located between the adjacent through holes (311).

5. The battery pack according to claim 2, wherein: A plurality of through holes (311) are formed on the panel (310); along the width direction of the panel (310), the plurality of through holes (311) form a plurality of parallelly arranged through hole groups (500); in each through hole group (500), the adjacent plurality of through holes (311) are maintained in parallel arrangement; and along the width direction of the panel (310), the through holes (311) in the adjacent through hole groups (500) are maintained in a facing arrangement; the reinforcing column (350) is located between the adjacent through holes (311).

6. The battery pack according to claim 1, wherein: A first protrusion (610) extending downward is provided at the bottom of the reinforcing plate (330), and a second protrusion (620) extending upward is provided at the top of the bottom plate (340); the first protrusion (610) and the second protrusion (620) can abut against each other.

7. The battery pack according to claim 1, wherein: It further includes a seal (2); the seal (2) is disposed between the battery cell (1) and the through hole (311); the outer side of the seal (2) abuts against the through hole (311), and the inner side of the seal (2) abuts against the outer wall of the battery cell (1).

8. The battery pack according to claim 1, wherein: It further includes a circulation pump. An inlet (303) and an outlet (302) are provided on the box body (30). The inlet (303) is connected to the inlet of the circulation pump, and the outlet (302) is connected to the outlet of the circulation pump; The inlet (303) is located in the heat exchange area or the protection area, and the outlet (302) is located in the heat exchange area or the protection area.

9. The battery pack according to claim 1, wherein: Along the circumferential direction of the frame (320), a ring-shaped boss (321) with ends connected is provided on the inner wall of the frame (320); the top of the boss (321) and the inner wall of the frame (320) form an upper boss, and the panel (310) is disposed on the upper boss; the bottom of the boss (321) and the inner wall of the frame (320) form a lower boss, and the reinforcing plate (330) abuts against the lower boss.

10. The battery pack according to claim 1, wherein: Above the immersion liquid level of the heat exchange medium in the liquid phase in the heat exchange area is a non-immersion area; the non-immersion area is configured to be able to accommodate the heat exchange medium in the gas phase; at least part of the battery cell (1) is immersed in the liquid-phase heat exchange medium; The battery pack further includes a negative pressure device, and the negative pressure device is communicated with the non-immersion area so that the air pressure in the non-immersion area can be lower than the ambient atmospheric pressure; At least part of the heat exchange medium is configured to be able to evaporate into steam in the inner cavity, and the steam quickly moves to the low-temperature area under the drive of the pressure difference and condenses to release heat to achieve cooling of the battery cell (1).

Images