A power battery thermal management device based on soft heat pipe

Abstract

The present invention relates to the technical field of thermal management of power batteries for electric vehicles, and specifically to a thermal management device for power batteries based on a soft heat pipe. The thermal management device for the power battery comprises: a battery pack, a battery box, a cover plate, a heat dissipation soft plate and a reflux component, and has the following beneficial effects: by arranging the heat dissipation soft plate, the heat generated by the battery is directed out of the narrow battery gap, and the phase change material absorbs heat and vaporizes by clinging to the wall of the heat dissipation soft plate under the action of the capillary force of the liquid absorption layer, and the vaporized phase change material condenses into liquid reflux at the upper end of the heat dissipation soft plate, and the coolant in the heat dissipation soft plate can be adsorbed on the entire liquid absorption layer by capillary force, which is beneficial to improving the uniformity of the battery surface temperature during the heat dissipation process; compared with the large-scale use of traditional heat pipes, the heat dissipation soft plate structure is more conducive to the lightweight design of the whole vehicle; the materials for preparing the heat dissipation soft plate are common and inexpensive, and no complex process is required, and the production cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management of power batteries for electric vehicles, and in particular to a thermal management device for power batteries based on a soft heat pipe. Background Art

[0002] Lithium-ion batteries are currently the first choice for power batteries for pure electric vehicles. Their performance is very sensitive to temperature. Too high, too low, and uneven temperature distribution will affect battery performance. In particular, high temperature can even lead to safety issues such as combustion and explosion.

[0003] Due to the requirements of long driving range and high power for electric vehicles, a large number of batteries need to be integrated and high-power discharge is required, which will inevitably cause the battery to generate more heat and the temperature to rise. The optimal operating temperature range of lithium-ion batteries is 25~40℃.

[0004] At present, air cooling and liquid cooling are commonly used in engineering for thermal management of batteries. For air cooling system, its structure is simple, easy to implement and low cost, which meets the requirements of lightweight vehicles, but the air heat exchange coefficient is small, and it is difficult to achieve the battery cooling effect in high temperature environment and high power operation; for liquid cooling system, compared with air cooling system, the heat dissipation is increased, and the system is more complicated.

[0005] Heat pipes are widely used in aerospace, electronic device cooling and other fields due to their high thermal conductivity and temperature uniformity. Placing them between adjacent batteries as heat transfer elements for battery cooling can quickly remove battery heat without consuming additional energy.

[0006] However, heat pipes are mostly made of metal. On the one hand, hard heat pipes are prone to collision and extrusion with batteries under complex driving conditions, causing battery damage. On the other hand, metal has a high density, and the large-scale use of heat pipes in battery packs is not conducive to the lightweight design of the entire vehicle. Furthermore, the relatively complicated heat pipe manufacturing process and the large-scale use of metal are not conducive to cost reduction. Summary of the invention

[0007] The object of the present invention is to provide a power battery thermal management device based on a flexible heat pipe to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A power battery thermal management device based on a flexible heat pipe, the power battery thermal management device comprising:

[0010] A battery pack, wherein the battery pack is composed of a plurality of groups of linearly arranged batteries fixedly connected;

[0011] A battery box, wherein a groove for accommodating a battery pack is provided in the battery box, and a cover plate is provided at the upper end of the battery box;

[0012] A heat dissipation soft plate, wherein a plurality of groups of the heat dissipation soft plates are clamped between adjacent batteries, the heat dissipation soft plates include a sealing outer layer, a liquid absorption layer, a structural support layer and a phase change material, the heat dissipation soft plate is in the form of a flexible sheet, the width of the heat dissipation soft plate is the same as the width of the battery, the lower end of the heat dissipation soft plate is flush with the lower end surface of the battery, the upper end of the heat dissipation soft plate extends to the upper end of the battery, the liquid absorption layer is tightly attached to the inner wall of the sealing outer layer, the liquid absorption layer is made of a super-hydrophilic material, the strength of the structural support layer is greater than the liquid absorption layer, the structural support layer is placed between the liquid absorption layers on both sides, and the structural support layer is made of a breathable material; the phase change material is made of a material that undergoes phase change between liquid and gas, the phase change temperature of the phase change material is within the operating temperature range of the battery, and the phase change material is filled and adsorbed in the liquid absorption layer;

[0013] The reflux component is installed in the cover plate. The reflux component includes a manifold and a reflux pipe connected to the upper end of the heat dissipation soft board. The other end of the manifold is connected to the heat dissipation exhaust pipe. The lower end of the heat dissipation exhaust pipe is provided with a reflux pipe connected to the heat dissipation soft board.

[0014] Preferably, a pair of stepped bottom plates are provided at the lower end of the groove, and a stepped groove is provided at the upper end of the groove. The battery pack is pressed onto the upper end of the stepped bottom plate, and a gap of 2-5 mm in height is left between the lower end of the battery pack and the inner wall of the lower end of the groove. The outer edge of the cover plate is pressed onto the stepped groove, and the cover plate is fastened to the upper end of the battery box by screws.

[0015] Preferably, the reflux assembly is installed in the inner cavity of the cover plate, a cooling coil is arranged between the heat dissipation pipe and the inner cavity of the cover plate, a water inlet and a water outlet connected to the cooling coil are arranged at both ends of the cover plate, the cooling coil is attached to the heat dissipation pipe, and the water inlet is connected to an external water pump.

[0016] Preferably, a plurality of groups of side grooves distributed linearly are arranged on the inner wall of the groove, the side grooves are directly opposite to the side walls of the heat dissipation soft plate, side plates are plugged and installed in the side grooves, and a double-chamber airbag is arranged between the side plates and the side walls of the heat dissipation soft plate.

[0017] Preferably, the side panel is provided with a first arc groove running through from top to bottom, and the outer walls on both sides of the heat dissipation soft plate are provided with a second arc groove, the first arc groove and the second arc groove are connected to each other, the double-chamber airbag is hollow in the shape of an 8, and the two ends of the double-chamber airbag are inserted in the first arc groove and the second arc groove, and the inner cavity of the double-chamber airbag is filled with expansion gas.

[0018] Preferably, the lower end of the cover plate is pressed onto the battery pack, the lower end surface of the cover plate is provided with a positioning slot facing the heat dissipation soft plate, the lower end of the manifold is provided with a sealing strip, and an air guide inner tube pressed onto the upper end of the structural support layer is vertically provided inside the sealing strip.

[0019] Preferably, a gap is left between the inner wall of the sealing strip and the outer wall of the air guide inner tube, the gap is located just above the liquid absorption layer, and the side wall of the gap is provided with a through hole connected to the lower end port of the return tube.

[0020] Preferably, the thickness of the heat dissipation soft plate is equal to the gap between adjacent batteries, the heat dissipation soft plate is sandwiched between adjacent batteries, the contact surface of the heat dissipation soft plate is provided with thermal conductive silicone grease to reduce contact thermal resistance, and the sealing outer layer is provided with puncture-proof high-temperature resistant plastic with elastic sealing.

[0021] Preferably, the liquid-absorbing layer is made of plant fiber raw silk non-woven fabric, and the structural support layer is made of air-permeable nylon mesh.

[0022] Preferably, the liquid filling amount of the phase change material in the heat dissipation soft plate does not exceed 1 / 10% of the total volume, and the liquid absorption layer can be completely filled at normal temperature and pressure. The phase change material is composed of monofluorodichloroethane with electrical insulation.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention arranges a heat dissipation soft plate to directionally guide the heat generated by the battery out of the narrow battery gap, thereby enhancing the heat dissipation of the battery thermal management system. The phase change material absorbs heat and vaporizes in close contact with the wall of the heat dissipation soft plate under the action of the capillary force of the liquid absorption layer. The vaporized phase change material condenses as liquid reflux at the upper end of the heat dissipation soft plate. This unpowered drainage structure does not require additional power consumption. The coolant in the heat dissipation soft plate can be adsorbed on the entire liquid absorption layer through capillary force, which is beneficial to improving the uniformity of the battery surface temperature during the heat dissipation process. The heat dissipation soft plate is flexible and can be bent at will according to the secondary heat dissipation device. It has flexible shape and can prevent battery damage caused by collision and extrusion compared to hard heat pipes. Compared with the extensive use of traditional heat pipes, the heat dissipation soft plate structure is more conducive to the lightweight design of the entire vehicle. The materials used to prepare the heat dissipation soft plate are common and inexpensive, do not require complex processes, and have low production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the battery box installation structure of the present invention;

[0026] Figure 2 A top view of a battery pack of the present invention;

[0027] Figure 3 It is a schematic diagram of the installation structure of the dual-chamber airbag of the present invention;

[0028] Figure 4 It is a schematic diagram of the three-dimensional structure of the battery box of the present invention;

[0029] Figure 5 It is a schematic diagram of the connection structure between the battery box and the battery pack of the present invention;

[0030] Figure 6It is a schematic diagram of the three-dimensional structure of the reflux assembly of the present invention;

[0031] Figure 7 It is a cross-sectional view of the heat dissipation soft board of the present invention.

[0032] In the figure: 1. battery box; 2. battery; 3. heat dissipation soft board; 4. stepped bottom plate; 5. groove; 6. stepped groove; 7. cover plate; 8. positioning slot; 9. water inlet; 10. water outlet; 11. air guide inner tube; 12. manifold; 13. return pipe; 14. side plate; 15. first arc groove; 16. double-chamber airbag; 17. side groove; 18. heat dissipation exhaust pipe; 19. sealing strip; 20. second arc groove; 31. sealing outer layer; 32. liquid absorption layer; 33. structural support layer; 34. phase change material. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figures 1 to 7 , the present invention provides a technical solution:

[0035] Embodiment 1:

[0036] A power battery thermal management device based on a soft heat pipe, the power battery thermal management device comprising: a battery pack, a battery box 1, a cover plate 7, a heat dissipation soft plate 3 and a reflux component.

[0037] The battery pack is composed of a plurality of linearly arranged batteries 2 that are fixedly connected. A groove 5 for accommodating the battery pack is provided in the battery box 1 , and a cover plate 7 is provided at the upper end of the battery box 1 .

[0038] The battery pack is fixedly installed by means of the groove 5 in the battery box 1 .

[0039] A plurality of groups of heat dissipation soft plates 3 are clamped between adjacent batteries 2. The heat dissipation soft plates 3 include a sealing outer layer 31, a liquid absorption layer 32, a structural support layer 33 and a phase change material 34. The heat dissipation soft plates 3 are in the form of flexible sheets. The width of the heat dissipation soft plates 3 is the same as the width of the battery 2. The lower end of the heat dissipation soft plates 3 is flush with the lower end surface of the battery 2. The upper end of the heat dissipation soft plates 3 extends to the upper end of the battery 2. The liquid absorption layer 32 is tightly attached to the inner wall of the sealing outer layer 31. The liquid absorption layer 32 is made of super hydrophilic material. The strength of the structural support layer 33 is greater than that of the liquid absorption layer 32. The structural support layer 33 is placed between the liquid absorption layers 32 on both sides. The structural support layer 33 is made of breathable material. The phase change material 34 is made of a material that undergoes phase change between liquid and gas. The phase change temperature of the phase change material 34 is within the battery operating temperature range. The phase change material 34 is filled and adsorbed in the liquid absorption layer 32.

[0040] The heat dissipation soft plate 3 is close to the battery 2. When the battery 2 is running at high power, the heat generated is absorbed by the phase change material 34. The phase change material 34 absorbs heat and vaporizes by the capillary force of the liquid absorption layer 32 when it is close to the wall of the heat dissipation soft plate 3. The vaporized phase change material 34 is ventilated along the structural support layer 33. The discharged phase change gas is condensed into liquid at the upper end of the heat dissipation soft plate 3 and refluxes. This unpowered drainage structure does not require additional power consumption. The refluxed coolant can be adsorbed on the entire liquid absorption layer through capillary force to circulate and dissipate heat, which is beneficial to maintaining the uniformity of the surface temperature of the battery 2 during the heat dissipation process.

[0041] The reflux assembly is installed in the cover plate 7, and the reflux assembly includes a manifold 12 and a reflux pipe 13 connected to the upper end of the heat dissipation soft board 3. The other end of the manifold 12 is connected to the heat dissipation exhaust pipe 18, and the lower end of the heat dissipation exhaust pipe 18 is provided with a reflux pipe 13 connected to the heat dissipation soft board 3.

[0042] The vaporized phase change material 34 is absorbed by the manifold 12 , condensed in the heat dissipation pipe 18 , and refluxed along the reflux pipe 13 to the upper end of the liquid absorption layer 32 .

[0043] Embodiment 2:

[0044] On the basis of Example 1, the material for preparing the heat dissipation soft plate 3 may be:

[0045] The thickness of the heat dissipation soft plate 3 is equal to the gap between adjacent batteries 2. The heat dissipation soft plate 3 is sandwiched between adjacent batteries 2. The contact surface of the heat dissipation soft plate 3 is provided with thermal conductive silicone grease to reduce the contact thermal resistance. The sealing outer layer 31 is provided with a puncture-proof and high-temperature resistant plastic with an elastic seal. The liquid absorption layer 32 is made of plant fiber raw silk non-woven fabric, and the structural support layer 33 is made of a breathable nylon mesh. The liquid filling amount of the phase change material 34 in the heat dissipation soft plate 3 does not exceed 1 / 3 of the total volume, and the liquid absorption layer 32 can be completely filled at room temperature and pressure. The phase change material 34 is composed of monofluorodichloroethane with electrical insulation. The preparation material is common and cheap, does not require complex processes, and has low production cost.

[0046] Embodiment 3:

[0047] On the basis of Example 2, a pair of stepped bottom plates 4 are provided at the lower end of the groove 5, and a stepped groove 6 is provided at the upper end of the groove 5. The battery pack is pressed on the upper end of the stepped bottom plate 4, and a gap of 2-5 mm in height is left between the lower end of the battery pack and the lower end inner wall of the groove 5. The outer edge of the cover plate 7 is pressed on the stepped groove 6, and the cover plate 7 is fastened to the upper end of the battery box 1 by screws.

[0048] The cover plate 7 is fixedly installed by providing the stepped groove 6, and a gap is left between the lower end of the battery pack and the inner wall of the groove 5 by providing the stepped bottom plate 4, so as to avoid heat accumulation caused by pressing and clogging, resulting in local overheating.

[0049] Embodiment 4:

[0050] On the basis of Example 2, the reflux assembly is installed in the inner cavity of the cover plate 7, a cooling coil is arranged between the heat dissipation pipe 18 and the inner cavity of the cover plate 7, and a water inlet 9 and a water outlet 10 connected to the cooling coil are arranged at both ends of the cover plate 7. The cooling coil is attached to the heat dissipation pipe 18, and the water inlet 9 is connected to an external water pump.

[0051] By setting up a cooling coil with circulating water supply, secondary cooling can be achieved to increase the efficiency of heat dissipation and condensation.

[0052] Embodiment 5:

[0053] On the basis of Example 4, a plurality of linearly distributed side grooves 17 are provided on the inner wall of the groove 5, the side grooves 17 are directly opposite to the side walls of the heat dissipation soft plate 3, the side plates 14 are plugged and installed in the side grooves 17, and a double-chamber airbag 16 is provided between the side plates 14 and the side walls of the heat dissipation soft plate 3.

[0054] By providing the dual-chamber airbag 16, buffering is achieved for the heat dissipation soft board 3 and the front and rear sides of the battery pack to avoid excessive squeezing and collision under vibration.

[0055] Embodiment 6:

[0056] On the basis of Example 5, a first arc groove 15 is provided on the side panel 14 and runs through from top to bottom, and a second arc groove 20 is provided on the outer walls on both sides of the heat dissipation soft plate 3, the first arc groove 15 and the second arc groove 20 are connected to each other, the double-chamber airbag 16 is hollow in the shape of a figure 8, and the two ends of the double-chamber airbag 16 are inserted in the first arc groove 15 and the second arc groove 20, and the inner cavity of the double-chamber airbag 16 is filled with expansion gas.

[0057] During the use of the battery box 1, due to the use environment, vibration is easily caused, which causes the batteries 2 in the battery pack to be relatively squeezed, and then the heat dissipation soft plate 3 is squeezed. The heat dissipation soft plate 3 is deformed and expands to both sides, so that one side of the dual-chamber airbag 16 is squeezed, and at the same time, the squeezing force is buffered to avoid excessive deformation. At the same time, the heat dissipation soft plate 3 is reset in time under the action of the internal pressure of the dual-chamber airbag 16.

[0058] Embodiment 7:

[0059] On the basis of Example 6, the lower end of the cover plate 7 is pressed onto the battery pack, and the lower end surface of the cover plate 7 is provided with a positioning slot 8 facing the heat dissipation soft plate 3, and the lower end of the manifold 12 is provided with a sealing strip 19, and the sealing strip 19 has an air guide inner tube 11 vertically arranged therein and pressed onto the upper end of the structural support layer 33.

[0060] By providing the inner air guide tube 11 , the vaporized phase change material 34 can be accurately absorbed into the heat dissipation reflux component.

[0061] A gap is left between the inner wall of the sealing strip 19 and the outer wall of the air guide inner tube 11 , the gap is located just above the liquid absorbing layer 32 , and a through hole connected to the lower end port of the return tube 13 is provided on the side wall of the gap.

[0062] The sealing strip 19 is provided with a gap fit with the inner air guide tube 11 so that the liquefied phase change material falls on the upper end of the liquid absorbing layer 32. The inner air guide tube 11 is used to separate the structural support layer 33 from the upper end of the liquid absorbing layer 32 to avoid blockage of the upper end of the structural support layer 33.

[0063] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A power battery thermal management device based on a soft heat pipe, characterized in that: The power battery thermal management device comprises: A battery pack, wherein the battery pack is composed of a plurality of groups of linearly arranged batteries (2) fixedly connected; A battery box (1), wherein a groove (5) for accommodating a battery pack is provided in the battery box (1), and a cover plate (7) is provided at the upper end of the battery box (1); A heat dissipation soft plate (3), wherein a plurality of groups of the heat dissipation soft plates (3) are sandwiched between adjacent batteries (2), the heat dissipation soft plates (3) comprising a sealing outer layer (31), a liquid absorbing layer (32), a structural support layer (33) and a phase change material (34), the heat dissipation soft plate (3) being in the form of a flexible sheet, the width of the heat dissipation soft plate (3) being the same as the width of the battery (2), the lower end of the heat dissipation soft plate (3) being flush with the lower end surface of the battery (2), the upper end of the heat dissipation soft plate (3) extending to the upper end of the battery (2), the liquid absorbing layer (32) being tightly attached to the battery (2), and the lower end of the heat dissipation soft plate (3) extending to the upper end of the battery (2). Closely attached to the inner wall of the sealing outer layer (31), the liquid absorbing layer (32) is made of a super-hydrophilic material, the strength of the structural support layer (33) is greater than that of the liquid absorbing layer (32), the structural support layer (33) is placed between the liquid absorbing layers (32) on both sides, and the structural support layer (33) is made of a breathable material; the phase change material (34) is made of a material that undergoes phase change between liquid and gas, the phase change temperature of the phase change material (34) is within the battery operating temperature range, and the phase change material (34) is filled and adsorbed in the liquid absorbing layer (32); A reflux assembly, the reflux assembly being mounted in the cover plate (7), the reflux assembly comprising a collector pipe (12) and a reflux pipe (13) connected to the upper end of the heat dissipation soft plate (3), the other end of the collector pipe (12) being connected to the heat dissipation exhaust pipe (18), the lower end of the heat dissipation exhaust pipe (18) being provided with a reflux pipe (13) connected to the heat dissipation soft plate (3); The inner wall of the groove (5) is provided with a plurality of groups of side grooves (17) distributed linearly, the side grooves (17) facing the side wall of the heat dissipation soft plate (3), a side plate (14) is inserted and installed in the side groove (17), and a double-chamber airbag (16) is provided between the side plate (14) and the side wall of the heat dissipation soft plate (3); the lower end of the cover plate (7) is pressed onto the battery pack, and the lower end surface of the cover plate (7) is provided with a positioning slot (8) facing the heat dissipation soft plate (3); the lower end of the manifold (12) is provided with a sealing strip (19), and an air guide inner tube (11) pressed onto the upper end of the structural support layer (33) is vertically provided inside the sealing strip (19); a gap is left between the inner wall of the sealing strip (19) and the outer wall of the air guide inner tube (11), the gap is located at the upper end of the liquid absorption layer (32), and the side wall of the gap is provided with a through hole connected to the lower end port of the return tube (13).

2. A power battery thermal management device based on a flexible heat pipe according to claim 1, characterized in that: A pair of stepped bottom plates (4) are provided at the lower end of the groove (5), and a stepped groove (6) is provided at the upper end of the groove (5). The battery pack is pressed onto the upper end of the stepped bottom plate (4), and a gap of 2-5 mm in height is left between the lower end of the battery pack and the inner wall of the lower end of the groove (5). The outer edge of the cover plate (7) is pressed onto the stepped groove (6), and the cover plate (7) is fastened to the upper end of the battery box (1) by screws.

3. A power battery thermal management device based on a flexible heat pipe according to claim 1, characterized in that: The reflux assembly is installed in the inner cavity of the cover plate (7); a cooling coil is provided between the heat dissipation pipe (18) and the inner cavity of the cover plate (7); a water inlet (9) and a water outlet (10) connected to the cooling coil are provided at both ends of the cover plate (7); the cooling coil is attached to the heat dissipation pipe (18); and the water inlet (9) is externally connected to a water pump.

4. A power battery thermal management device based on a flexible heat pipe according to claim 1, characterized in that: The side plate (14) is provided with a first arc groove (15) penetrating vertically, and the outer walls of both sides of the heat dissipation soft plate (3) are provided with second arc grooves (20), the first arc groove (15) and the second arc groove (20) are connected to each other, the double-chamber airbag (16) is hollow in the shape of a figure 8, and the two ends of the double-chamber airbag (16) are inserted into the first arc groove (15) and the second arc groove (20), and the inner cavity of the double-chamber airbag (16) is filled with expansion gas.

5. The power battery thermal management device based on a flexible heat pipe according to claim 1, characterized in that: The thickness of the heat dissipation soft plate (3) is equal to the gap between adjacent batteries (2). The heat dissipation soft plate (3) is sandwiched between adjacent batteries (2). The contact surface of the heat dissipation soft plate (3) is provided with thermal conductive silicone grease to reduce contact thermal resistance. The sealing outer layer (31) is provided with puncture-proof and high-temperature resistant plastic with elastic sealing.

6. A power battery thermal management device based on a flexible heat pipe according to claim 5, characterized in that: The liquid-absorbing layer (32) is made of plant fiber raw silk non-woven fabric, and the structural support layer (33) is made of a nylon mesh with air permeability.

7. A power battery thermal management device based on a flexible heat pipe according to claim 6, characterized in that: The liquid filling amount of the phase change material (34) in the heat dissipation soft plate (3) does not exceed 1 / 3 of the total volume, and can completely fill the liquid absorption layer (32) at normal temperature and pressure. The phase change material (34) is composed of monofluorodichloroethane with electrical insulation properties.

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