CN209766601U - Battery pack thermal management system based on flat heat pipe - Google Patents

Abstract

the utility model relates to the field of power battery thermal management, and discloses a battery pack thermal management system based on a flat heat pipe, which comprises a battery pack, a flat heat pipe, a U-shaped graphite sheet and a heat exchange plate; the battery pack comprises a plurality of square single batteries, and the U-shaped graphite sheets correspond to the single batteries one by one; the U-shaped graphite sheet at least covers two opposite side surfaces of the single battery to form a battery unit, and the plurality of battery units are sequentially attached to form a battery module; the plurality of heat exchange plates are arranged at intervals in sequence, the battery module is arranged in the interval between two adjacent heat exchange plates along the length direction of the battery module, and the flat heat pipe is positioned between the battery module and the heat exchange plates. The beneficial effects are that: the system has simple and compact structure and small occupied area, and can effectively improve the uniformity of the internal temperature of the battery pack while efficiently radiating/heating the battery pack.

Description

A battery pack thermal management system based on flat heat pipes

technical field

The utility model relates to the field of thermal management of power batteries, in particular to a thermal management system of a battery pack based on a flat heat pipe.

Background technique

As the main power source of electric vehicles, the parameters and performance of batteries directly affect the power, safety and economy of electric vehicles. Heat will be generated during battery work, which will increase the temperature of the battery, resulting in changes in battery voltage and thermal runaway; in cold winter areas, the battery temperature is too low will reduce the battery capacity, power and charge and discharge efficiency, which will reduce the mileage and battery life of electric vehicles. The maximum speed is greatly reduced. The uneven temperature of the battery pack will lead to uneven discharge of the battery pack, and the local temperature difference of the single battery will even cause pressure difference and mechanism expansion. Therefore, it is particularly important to study efficient battery thermal management technologies to improve the performance of electric vehicles.

Contacting the heat pipe or cold water pipe with the battery is a common heat dissipation method for battery thermal management to absorb the heat generated by the battery, which makes the heat exchange area extremely limited, the heat exchange is concentrated, and the temperature distribution inside the single battery is uneven. When the battery is heated, there is also a phenomenon in which the temperature difference is increased due to heating concentration.

Utility model content

The purpose of this utility model is to overcome the shortcomings of the above prior art and provide a battery pack heat management system based on flat heat pipes, which aims to efficiently dissipate heat/heat the single battery while ensuring the uniform temperature of the battery pack sex.

The purpose of this utility model is achieved through the following technical solutions: a battery pack thermal management system based on a flat heat pipe, including a battery pack, a flat heat pipe, a U-shaped graphite sheet, and a heat exchange plate with a circulating working fluid inside; The group includes a plurality of square single cells, the U-shaped graphite sheets correspond to the single cells one by one, and the U-shaped graphite sheets cover at least two opposite sides of the single cells to form a battery unit. A plurality of battery units are sequentially bonded to form a battery module; wherein, the two side plates of each U-shaped graphite sheet are parallel to the length direction of the battery module, and a plurality of heat exchange plates are arranged at intervals in sequence, and the battery module is arranged along its length. The direction is set in the interval between two adjacent heat exchange plates. The flat heat pipe is located between the battery module and the heat exchange plate. One side of the flat heat pipe is closely attached to the U-shaped graphite sheet, and the other side is in contact with the heat exchange plate. snug fit.

Further, the size of the two side plates of the U-shaped graphite sheet matches the two opposite sides of the single battery, so that the two side plates of the U-shaped graphite sheet completely cover the two opposite sides of the single battery , both side plates of the U-shaped graphite sheet are parallel to the length direction of the battery module.

Further, the U-shaped graphite sheet completely covers three adjacent sides of the single battery, two of which are opposite to each other, and these two sides are parallel to the length direction of the battery module, and the other side is perpendicular to the battery module In the length direction of the U-shaped graphite sheet, the U-shaped graphite sheet has opposite open ends and closed ends. In the same battery module, the open end of the U-shaped graphite sheet is attached to the back of the closed end of the adjacent U-shaped graphite sheet, so that the monomer The four sides of the battery are bonded to the U-shaped graphite sheet.

Further, the heat exchange plate has a plurality of circulation flow channels inside, and each of the circulation flow channels has a working medium inlet and a working medium outlet that are oppositely arranged.

Further, the circulation flow channel includes at least two parallel flow channels, each parallel flow channel is connected in parallel, one end of each parallel flow channel is connected to the working fluid inlet, and the other end of each parallel flow channel is Connect with working fluid outlet.

Further, the flat heat pipe is a sintered liquid-absorbent wick type steam cavity flat heat pipe with supporting columns inside.

Further, the battery module has a cuboid structure.

Further, thermal conductive silica gel is coated between the flat heat pipe and the U-shaped graphite sheet and between the flat heat pipe and the heat exchange plate.

A working method of a battery pack thermal management system based on flat heat pipes, comprising the following steps,

Heat dissipation process: When the working temperature of the battery pack is too high, the working fluid circulating in the heat exchange plate is the cooling medium, and the heat generated by the single battery is transferred to the heat exchange plate through U-shaped graphite sheets and flat heat pipes in turn; at the same time, The cooling working fluid flows in from the working fluid inlet, and flows out from the working fluid outlet after absorbing heat to cool the battery pack; during the heat dissipation process, the side where the flat heat pipe contacts the U-shaped graphite sheet is the heat-absorbing surface, and the flat heat pipe and the heat exchange The side where the plate contacts is the heat release surface;

Heating process: When the battery pack is working in a low-temperature environment, the working fluid circulating in the heat exchange plate is the heating medium, which acts as a heat source, flows in from the working medium inlet, releases heat, and flows out from the working medium outlet; at the same time, the heat Through the heat exchange plate, flat heat pipe and U-shaped graphite sheet in turn, it is transmitted to the battery pack to realize the heating of the battery pack; The side where the graphite sheet contacts is the heat release surface.

Further, the cooling working medium is water or ethylene glycol aqueous solution, and the heating working medium is water or ethylene glycol aqueous solution.

Compared with the prior art, the utility model has the following advantages:

1. The thermal management system of the battery pack of the present invention has a simple and compact structure, a small footprint, convenient and flexible layout, high safety, and low manufacturing cost. Combining graphite sheets, flat heat pipes and heat exchange plates, on the basis of graphite sheets, combined with the characteristics of large heat exchange area and strong heat transfer performance of flat heat pipes, the temperature distribution of the battery pack is uniform, and the single cells do not directly contact The heat exchange plate can effectively avoid the danger of liquid leakage and greatly improve the safety of the battery thermal management system.

2. The surroundings of the single battery in the utility model are covered by graphite sheets. Graphite has good plasticity and toughness, is light and thin, and has strong thermal conductivity. Using graphite as a thermal conductivity material is beneficial to the uniform conduction of heat and effectively improves the performance of the battery pack. Uniformity of temperature.

3. The flat heat pipe in this utility model is a sintered liquid-absorbing core type steam chamber flat heat pipe with supporting columns inside; compared with ordinary heat pipes, the flat heat pipe structure can have better contact with graphite sheets and heat exchange plates ; The support column made of sintered powder in the heat pipe can effectively improve the rigidity and critical heat flux density of the flat heat pipe. The support column can not only provide auxiliary liquid circulation channels, but also provide additional heat conduction channels, thereby reducing thermal resistance and improving Heat exchange efficiency: the internal working medium of the flat heat pipe transfers heat evenly in the form of phase change in the steam chamber, so that the surface temperature of the flat heat pipe is uniform, which is conducive to improving the temperature uniformity of the battery pack.

4. The arrangement of the parallel channels in the heat exchange plate in the utility model is simple, the resistance of the flowing working fluid is small in the flow process, and the energy loss is small, which is beneficial to reduce the secondary energy consumption in the heat management system. The materials used in the utility model are energy-saving and environment-friendly, easy to install and easy to maintain, can solve the heat exchange requirements of the square battery pack under different working conditions, ensure that the battery works in a suitable temperature range, and have broad application prospects.

Description of drawings

Fig. 1 shows a schematic structural view of a battery pack thermal management system based on a flat heat pipe according to the present invention;

Figure 2 shows a top view of Figure 1;

Fig. 3 shows the exploded diagram of place A in Fig. 2;

Fig. 4 shows a schematic structural diagram of bonding a U-shaped graphite sheet and a single battery according to the utility model;

Figure 5 shows a schematic structural view of the heat exchange plate according to the present invention;

Fig. 6 shows a schematic diagram of the flow of working fluid in the circulation channel according to the present invention;

In the figure, 1 is a U-shaped graphite sheet; 101 is an open end; 102 is a closed end; 2 is a battery pack; 201 is a single battery; 3 is a flat heat pipe; 4 is a heat exchange plate; 401 is a circulation channel; 402 is Working fluid import; 403 is working fluid export; 404 is parallel flow channel.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Example:

A battery pack thermal management system based on flat heat pipes as shown in Figures 1-3 includes a battery pack 2, a flat heat pipe 3, a U-shaped graphite sheet 1 and a heat exchange plate 4 with a circulating working medium inside; The battery pack 2 includes a plurality of square unit batteries 201, the U-shaped graphite sheet 1 corresponds to the unit batteries 201 one by one, and the U-shaped graphite sheet 1 covers at least two opposite sides of the unit batteries 201 To form a battery unit, a plurality of battery units are laminated in sequence to form a battery module, wherein the two side plates of the U-shaped graphite sheet 1 are parallel to the length direction of the battery module, (that is, the two sides of the U-shaped graphite sheet 1 The side plates are arranged sequentially along the length direction of the battery module), and a plurality of heat exchange plates 4 are sequentially arranged at intervals. Between the module and the heat exchange plate 4 , one side of the flat heat pipe 3 is in close contact with the U-shaped graphite sheet 1 , and the other side is in close contact with the heat exchange plate 4 . The U-shaped graphite sheet 1 on both sides of the single battery 201 is bonded to the flat heat pipe 3, and the U-shaped graphite sheet 1 is in indirect contact with the heat exchange plate 4 through the flat heat pipe 3. Adopting this structure can effectively avoid the internal flow path of the heat exchange plate 4. Safety problems caused by quality leakage. Adjacent battery modules use the same heat exchange plate 4 for heat exchange, making the system simple and compact in structure and occupying a small area. When the temperature of the battery pack 2 is high, the heat generated by the single battery 201 is transferred to the flat heat pipe 3 through the U-shaped graphite sheet 1, and then the cooling fluid flowing in the heat exchange plate 4 takes away the heat, thereby realizing the cooling of the battery pack 2. cooling; when the working environment temperature of the battery pack 2 is low, the heating medium flows in the heat exchange plate 4, and the heat of the heating medium is transferred to the single battery 201 through the flat heat pipe 3 and the U-shaped graphite sheet 1, so as to realize the cooling of the battery. Group 2 heating. This design is convenient, flexible and highly safe, and can ensure that the single battery 201 works within a suitable temperature range.

The size of the two side plates of the U-shaped graphite sheet 1 matches the two opposite sides of the unit battery 201, so that the two side plates of the U-shaped graphite sheet 1 completely cover the two opposite sides of the unit battery 201. On the side, both side plates of the U-shaped graphite sheet are parallel to the length direction of the battery module. Adopting this structure can improve the heat exchange efficiency between the U-shaped graphite sheet 1 and the single battery 201 , and improve the temperature uniformity of the single battery 201 itself.

As shown in Figures 3 and 4, the volume wrapped by the U-shaped graphite sheet 1 is equal to the volume of the single battery 201, so that the U-shaped graphite sheet 1 completely covers three adjacent sides of the single battery 201, Two of the sides are opposite to each other, and the two sides are parallel to the length direction of the battery module, and the other side is perpendicular to the length direction of the battery module. The U-shaped graphite sheet 1 has an opposite open end 101 and a closed end 102, the same In the battery module, the open end 101 of the U-shaped graphite sheet 1 is attached to the back of the closed end 102 of the adjacent U-shaped graphite sheet 1, so that the four sides of the single battery 201 are attached to the U-shaped graphite sheet 1 . With this structure, the four sides of the single battery 201 are surrounded by the U-shaped graphite sheet 1 , and the adjacent single batteries 201 are not in contact with each other, which is beneficial to reduce the mutual influence between the adjacent single batteries 201 . At the same time, the U-shaped graphite sheet 1 has good thermal conductivity, which is beneficial to reduce the temperature difference between the single cells 201 and maintain the temperature uniformity of the battery pack 2 .

As shown in FIG. 5 , the heat exchange plate 4 has a plurality of circulation flow channels 401 inside, and each circulation flow channel 401 has a working medium inlet 402 and a working medium outlet 403 oppositely arranged. Setting a plurality of circulation flow channels 401 can improve the uniformity of the distribution of the working medium in the heat exchange plate 4, thereby improving the heat exchange efficiency of the entire system.

As shown in Figures 5 and 6, the circulation channel 401 includes three parallel channels 404, each parallel channel 404 is connected in parallel, one end of each parallel channel 404 is connected to the working fluid inlet 402, each The other ends of the parallel channels 404 are connected to the working medium outlet 403 . The parallel flow channels 404 are arranged in parallel, and the parallel flow channels 404 are all rectangular, with reasonable design and simple structure, so that the resistance of the flowing working fluid is small during the flow process, and the energy loss is small, which is beneficial to reduce the energy loss in the heat management system. secondary energy consumption.

The flat heat pipe 3 is a sintered liquid-absorbing core type steam cavity flat heat pipe with supporting columns inside. The flat heat pipe 3 with a steam chamber not only has a strong heat transfer capacity in the normal direction of the plate, but also helps to transfer the heat generated by the heat source evenly on the entire plate, which can effectively eliminate hot spots and improve the heat exchange effect; the flat heat pipe The flat structure of 3 is also easy to contact with U-shaped graphite sheet 1 and heat exchange plate 4, which simplifies the installation of the system. This kind of flat heat pipe 3 can be purchased from the market.

The battery module has a cuboid structure. The battery module with a cuboid structure matches the flat structure of the flat heat pipe 3, and the whole system is compact in structure, which effectively improves heat exchange efficiency.

Between the flat heat pipe 3 and the U-shaped graphite sheet 1 and between the flat heat pipe 3 and the heat exchange plate 4 are coated with thermally conductive silica gel. This setting can reduce the thermal resistance and improve the heat transfer efficiency of the system.

A working method of a battery pack thermal management system based on flat heat pipes, comprising the following steps,

Heat dissipation process: when the working temperature of the battery pack 2 is too high, the working medium circulating in the heat exchange plate 4 is the cooling medium, and the heat generated by the single battery 201 is transferred to the heat exchanger through the U-shaped graphite sheet 1 and the flat heat pipe 3 in sequence. Hot plate 4; At the same time, the cooling working fluid flows in from the working fluid inlet 402, and flows out from the working fluid outlet 403 after absorbing heat, so as to realize the cooling of the battery pack 2; during the heat dissipation process, the contact between the flat heat pipe 3 and the U-shaped graphite sheet 1 One side is the heat-absorbing surface, and the side where the flat heat pipe 3 is in contact with the heat exchange plate 4 is the heat-releasing surface;

Heating process: when the battery pack 2 works in a low-temperature environment, the working fluid circulating in the heat exchange plate 4 is a heating medium, and the heating medium acts as a heat source, flows in from the working medium inlet 402, and flows out from the working medium outlet 403 after releasing heat Simultaneously, the heat passes through the heat exchange plate 4, the flat heat pipe 3 and the U-shaped graphite sheet 1 successively, and is transferred to the battery pack 2 to realize the heating of the battery pack 2; The side is the heat-absorbing surface, and the side where the flat heat pipe 3 is in contact with the U-shaped graphite sheet 1 is the heat-releasing surface.

The cooling working medium is water or ethylene glycol aqueous solution, and the heating working medium is water or ethylene glycol aqueous solution. In specific use, the cooling working medium is at normal temperature, and the heating working medium can be used after being heated.

The specific implementation described above is a preferred embodiment of the utility model, and does not limit the utility model. Any other changes or other equivalent replacement methods that do not deviate from the technical solution of the utility model are included in the utility model. within the scope of the new protection.

Claims (8)

1. the utility model provides a group battery thermal management system based on flat heat pipe which characterized in that: the heat exchanger comprises a battery pack, a flat heat pipe, a U-shaped graphite sheet and a heat exchange plate with a circulating flowing working medium inside; the battery pack comprises a plurality of square single batteries, the U-shaped graphite sheets correspond to the single batteries one by one, the U-shaped graphite sheets at least cover two opposite side surfaces of the single batteries to form a battery unit, and the plurality of battery units are sequentially attached to form a battery module; the battery module is arranged in the interval between two adjacent heat exchange plates along the length direction of the battery module, the flat heat pipe is positioned between the battery module and the heat exchange plates, one side surface of the flat heat pipe is tightly attached to the U-shaped graphite sheet, and the other side surface of the flat heat pipe is tightly attached to the heat exchange plates.

2. The flat heat pipe based battery pack thermal management system of claim 1, wherein: the size of the two side plates of the U-shaped graphite sheet is matched with the two opposite side surfaces of the single battery, so that the two side plates of the U-shaped graphite sheet completely cover the two opposite side surfaces of the single battery, and the two side plates of the U-shaped graphite sheet are parallel to the length direction of the battery module.

3. The flat heat pipe based battery pack thermal management system of claim 1, wherein: the U type graphite flake totally wraps three adjacent sides of single battery, wherein two sides set up relatively, and these two sides are on a parallel with the length direction of battery module, the length direction of another side perpendicular to battery module, U type graphite flake has relative open end and blind end, and in same battery module, the open end of U type graphite flake is rather than the back laminating of the blind end of adjacent U type graphite flake to make four sides of single battery all laminate with U type graphite flake.

4. The flat heat pipe based battery pack thermal management system of claim 1, wherein: the heat exchange plate is internally provided with a plurality of circulation flow channels, and each circulation flow channel is provided with a working medium inlet and a working medium outlet which are oppositely arranged.

5. The flat heat pipe based battery pack thermal management system of claim 4, wherein: the circulating flow channel comprises at least two parallel flow channels, each parallel flow channel is connected in parallel, one end of each parallel flow channel is connected with the working medium inlet, and the other end of each parallel flow channel is connected with the working medium outlet.

6. The flat heat pipe based battery pack thermal management system of claim 1, wherein: the flat heat pipe is a sintered wick-absorbing type steam cavity flat heat pipe with a support column inside.

7. The flat heat pipe based battery pack thermal management system of claim 1, wherein: the battery module is of a cuboid structure.

8. The flat heat pipe based battery pack thermal management system of claim 1, wherein: and heat-conducting silica gel is coated between the flat heat pipe and the U-shaped graphite sheet and between the flat heat pipe and the heat exchange plate.