CN103594755A - Power battery group liquid flow non-contact thermal-control device - Google Patents

Abstract

The invention discloses a power battery group liquid flow non-contact thermal-control device. In a heat management structure of the power battery group liquid flow non-contact thermal-control device, a high-thermal conductivity piece such as a graphite piece is used as a heat exchange bridge of a circulating liquid flow and a power battery. Through an excellent plane heat conduction capability of the graphite piece, heat is transferred effectively and power battery group temperature stability and uniformity are guaranteed. A liquid flowing process and a medium space between the existing batteries are avoided so that power battery package volume and weight are reduced obviously and compactness and lightweighting of a power battery group thermal-control package are realized.

Description

Power battery group liquid flow non-contact thermal control device

technical field

The invention belongs to the field of thermal management of electric vehicles and power batteries, and in particular relates to a power battery liquid flow heat exchange structure and a synergistic control method for improving the temperature balance of battery packs. the

Background technique

The increasingly serious energy and environmental problems have made traditional internal combustion engine vehicles face severe challenges, and more and more attention has been paid to energy-saving and environmentally friendly electric vehicles. The world's major automobile manufacturers have already regarded electric vehicles (Electric Vehicle, EV) and hybrid electric vehicles (Hybrid Electric Vehicle, HEV) as important directions for future automobile development. the

The power battery is a key component of electric vehicles, which directly affects the performance and range of electric vehicles. The driving conditions of the car are complex and changeable, high temperature environment, heavy load, instant acceleration, and if the heat is not dissipated in time when climbing, the battery temperature will be too high, which will greatly affect the battery capacity and service life; at the same time, poor temperature balance in the battery pack will also cause Cause internal friction, affect the efficiency and cruising range. Therefore, timely and effective thermal control of power batteries is particularly important. the

At present, the temperature control methods for power batteries are mainly air-cooled and liquid-cooled according to the classification of heat transfer media. The air-cooled system has simple structure, light weight and low cost, and is mainly used in the case of simple structure and small power load; the disadvantages are low heat transfer coefficient between battery walls, slow cooling speed, poor thermal response, and poor heat transfer. low efficiency. However, the liquid cooling system has strong heat exchange capacity and fast heat transfer rate, which is convenient for two-way thermal control of heating and cooling, and easy for integrated thermal management of the whole vehicle, that is, the strong controllability of the liquid flow is conducive to the thermal control linkage of the battery, motor and control unit, and It is thermally coupled with air conditioning and other systems, which is beneficial to realize energy complementary reuse. The liquid flow structure has become the mainstream choice for the battery pack system with large load and high power. Of course, the liquid medium process space and heat dissipation circulation system usually have a large space, high sealing requirements, complex structure, and heavy weight, which also restrict the development and application of liquid flow systems. Therefore, the demand for liquid flow structure with compact structure and strong heat transfer capacity has always been the focus and key technology of people's continuous efforts. Such as graphite heat conduction sheet not only has extremely high thermal conductivity, but also has a unique grain orientation, which makes the thermal conductivity of the sheet type as high as 1500W/m·k or more. Such outstanding planar thermal conductivity is not only conducive to the realization of planar heat transfer The temperature of the battery is uniform, and it is convenient for the heat to spread out. Thus, it is possible to avoid the complicated liquid flow structure from contacting the batteries one by one to transfer heat, that is, the so-called non-contact thermal control structure means that the liquid flow process does not adopt the form of direct convective heat exchange throughout the battery group, but through efficient heat conduction and heat exchange. After the sheet completes heat conduction and heat transfer, it then convects and transfers heat with the external liquid flow medium. In addition, the unit weight of this type of material heat conduction sheet is 25% lighter than aluminum and 75% lighter than copper. Such a good lightweight and high-conductivity material further reduces the weight of a large-capacity battery pack. The device method of the present invention proposes to apply graphite and other light sheets with high thermal conductivity to the thermal control and heat exchange structure of the grouped liquid flow of the power battery, and use the high thermal conductivity sheet as the heat transfer medium for the group intervals of the batteries, and then transfer the heat to the battery pack Laminated outer end liquid flow heat exchanger. Among them, the liquid flow does not participate in the heat exchange between the batteries, and the flow of the liquid flow does not run through the batteries, so that the liquid flow cavity is in a non-contact state. Therefore, the liquid flow non-contact thermal control device ensures the good heat transfer characteristics and temperature balance of the battery, reduces the liquid medium capacity and process space, and simplifies the heat exchange structure of the battery group; in the realization of the compact volume and the high-capacity battery group At the same time of light weight, the high thermal conductivity sheet is used to effectively implement the thermal control and thermal management of the power battery. the

There are some related patents in the technology of power battery liquid flow and heat transfer, such as the Chinese patent "A power battery thermal management system based on pulsating heat pipes (201110066246.5)", which proposes that there are reciprocating heat pipes distributed on the surface of each battery cell Bending rows of pulsating heat pipe heat exchange structure; Chinese patent "battery thermal management equipment with efficient and balanced heat dissipation function and electric heating function (201310063494.3)" mentions that single batteries are arranged The thermal control of the battery by variable latent heat; the Chinese patent "A water-cooled thermal management system for electric vehicle battery packs (201210376200.8)" proposes that the cooling partitions with cooling channels inside are closely attached to both sides of the power battery unit, and the cooling channels The two ends are respectively connected with the liquid inlet pipe and the liquid outlet pipe to realize the liquid cooling temperature control of the power battery. However, the battery thermal management system involved in these patents has a complex heat transfer structure, a large liquid medium capacity and a large process space, and does not use high thermal conductivity sheets for heat transfer efficiency control to achieve a simple and lightweight structure. the

Internationally, some relevant research has been carried out on liquid cooling of power batteries, such as the US patent "Vehicle Battery Cooling structure (US20120055725A1)", "Power Battery Pack Cooling Apparatus (US201200282511A1)", "Vehicle Battery Cooling Device (US20117905308B2)" "Cooling System For a Battery Pack (US20036569556B2)" etc. However, issues such as the use of high thermal conductivity sheets for heat transfer efficiency control and structural optimization have not been elaborated. the

Contents of the invention

The present invention proposes that in the thermal management structure of the non-contact thermal control device for the grouped liquid flow of the power battery, a high thermal conductivity sheet such as graphite is used as a heat exchange bridge between the circulating liquid flow and the power battery, and the superior plane thermal conductivity of the graphite sheet is used to achieve high efficiency. Transfer heat, ensure the temperature stability and balance of the battery pack, remove the liquid flow process and medium space between the batteries in the past, significantly reduce the volume and weight of the battery pack, and realize the compactness and light weight of the power battery thermal control pack. the

Description of drawings

Fig. 1 Schematic diagram of heat exchange between liquid flow medium and power battery pack. the

Figure 2 Schematic diagram of the structure of the high thermal conductivity heat exchanger. Among them, the dotted line frame is the groove, louver and other enhanced heat transfer structures opened on the surface of the heat transfer fins. the

Fig. 3 is a schematic diagram of arrangement of power battery cells and heat exchange fins with high thermal conductivity in groups. the

The numbers and corresponding names of the components in the figure are as follows:

In Fig. 1-3: 1-high heat conduction heat exchange sheet, 2-power battery unit, 3-enhanced heat exchange structure such as grooves, louvers, 4-liquid flow medium, 5-end liquid flow heat exchanger

Detailed ways

As shown in the drawings, in this embodiment, high thermal conductivity heat exchange fins 1 are arranged on both sides of the unit cells 2 of the power battery group, and are arranged in groups at intervals, so as to realize decent heat dissipation of the battery by utilizing its high thermal conductivity. Transmission and temperature uniformity, to ensure efficient heat transfer and compact structure of stacked batteries. The high thermal conductivity heat exchange sheet 1 and the side of the battery 2 are attached with a high thermal conductivity adhesive to reduce thermal resistance and achieve good heat transfer between the battery body and the high thermal conductivity heat exchange sheet. the

Furthermore, the end liquid flow heat exchanger 5 is set, and the end of the high heat conduction heat exchange sheet 1 is placed in the end liquid flow heat exchanger 5, and the high heat conduction heat exchanger is made by utilizing the superior plane heat conduction capacity of the high heat conduction sheet such as graphite. The heat sheet 1 is used as a heat exchange bridge between the circulating liquid flow and the power battery, and flows through the end liquid flow heat exchanger 5, and the forward and reverse flow medium 4 mainly exchanges heat with the power battery 2 through the high thermal conductivity heat exchange sheet 1. Optimize the heat exchange structure, reduce the liquid medium capacity and process space, reduce the total weight of the battery pack, and realize the effective heat exchange between the heat transfer heat of the battery body cooling and preheating and the liquid flow medium. the

At the same time, the insertion part of the high thermal conductivity heat exchange fin 1 in the end liquid flow heat exchanger 5 is provided with enhanced heat exchange structures 3 such as grooves and louvers, and the forward and reverse liquid flow media 4 are placed in the end liquid flow heat exchanger 5. The heat exchange structure 3 is enhanced by scouring grooves and louvers along the liquid flow channel, and using multi-dimensional convective heat transfer to realize efficient heat exchange in the flow of the liquid flow medium and ensure the rapid heat transfer of the liquid flow thermal control of the battery group. the

Claims (4)

1. The non-contact thermal control device of the power battery group liquid flow, which is characterized in that the surface of both sides of the single battery (2) of the power battery group is arranged with high heat conduction heat exchange fins (1), and the high heat conduction capacity is used to realize the good appearance of the battery Excellent heat transfer and temperature uniformity ensure efficient heat transfer and compact structure of stacked batteries. the 2. According to claim 1, the high thermal conductivity heat exchange sheet of the power battery group liquid flow non-contact thermal control device is characterized in that an end liquid flow heat exchanger (5) is provided, and the high thermal conductivity heat exchange sheet ( 1) The end is placed in the end liquid flow heat exchanger (5) to realize the effective heat exchange between the heat conduction heat transfer amount for cooling and preheating of the battery body and the liquid flow medium. the 3. According to claim 2, the end liquid flow heat exchanger (5) of the power battery group liquid flow non-contact thermal control device is characterized in that the high thermal conductivity of the end liquid flow heat exchanger (5) The insertion part of the heat exchange fin (1) is equipped with enhanced heat exchange structures (3) such as grooves and louvers, and uses multi-dimensional convection heat transfer to realize efficient heat exchange of the liquid flow medium (4) and ensure the thermal control of the liquid flow in the battery group. The heat is transferred quickly. the 4. According to claim 1, the power battery group liquid flow non-contact thermal control device is characterized in that the high thermal conductivity heat exchange sheet (1) is attached to the side of the battery (2) with a high thermal conductivity adhesive to reduce heat conduction Thermal resistance, to achieve good heat transfer between the battery body and the high thermal conductivity heat exchange sheet. the

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