WO2021026979A1 - Plate-type heating and cooling heat conduction apparatus, and temperature-controllable lithium battery pack using same - Google Patents

Abstract

A plate-type heating and cooling heat conduction apparatus, comprising a heating and cooling heat conduction member (1), wherein the heating and cooling heat conduction member (1) is composed of a heat exchange plate (105) and an infrared heating film (106) attached to a side face of the heat exchange plate (105); the heat exchange plate (105) is provided with a first flow guide cavity (103) used for loading a graphene fluid medium; in a low-temperature environment, the infrared heating film (106) is electrified and emits heat so as to heat an object in contact therewith; and in a high-temperature environment, the electrification of the infrared heating film (106) is stopped, and heat generated by the object itself is transferred to the graphene fluid medium by means of heat conduction. The flowing of a graphene fluid medium takes away heat, such that the aim of cooling an object is achieved, and the aim of the temperature of the object being controllable is achieved by means of heating, temperature rise, heat conduction, and cooling; thus, it is guaranteed that the object is not affected by environmental changes, and the original functions of the object are not affected.

Description

Plate type heating and cooling heat conduction device and temperature controllable lithium battery pack adopting the device

This application is based on the Chinese patent application with the application number 201910745766.5 and the filing date of August 13, 2019, and claims its priority. The entire content of the application is hereby incorporated into this application as a whole.

Technical field

This application relates to the technical field of temperature control devices, in particular to a plate-type heating and cooling heat conduction device and a temperature controllable lithium battery pack using the device.

Background technique

In new energy auto parts, lithium batteries are widely used as a source of power energy. The operating temperature of lithium batteries is limited to a certain range. In a low temperature environment, the increase in electrolyte viscosity prevents lithium ions from traveling between the positive and negative electrodes, which will affect the discharge characteristics. Below -40°C, the electrolyte will crystallize ice, resulting in capacity Reduce to no current output. According to literature: -20℃ is 50% less than 25℃. The power attenuation is more obvious, -20℃, 0.2C discharge voltage platform 3.3V; -20℃, 0.5C discharge, voltage platform <3V; -20℃, 1C discharge almost no current output [Chen Jitao, Zhou Henghui, Ni Jiangfeng, Chang Wen Bao, Ci Yunxiang, Low-temperature charge and discharge performance of C/LiCoO ₂ series lithium batteries [J] Battery 2004, Vol. 34, No. 2], will cause electric vehicles to fail to start.

When a lithium battery is charged and discharged, the internal heat produced by the battery includes: ohmic heat, electrochemical reaction heat, side reaction heat and polarization heat of internal resistance in the battery system; the side reaction heat is due to the decomposition of the electrolyte during the battery use. However, polarization heat is generated due to the deviation of the electromotive force of the electrode from the equilibrium electromotive force. During the continuous charging or discharging process of the lithium battery, if the internal heat of the battery is not timely generated through effective heat dissipation, the battery temperature may be overheated in a high temperature environment. High and cause thermal runaway, and in severe cases, the battery may even catch fire and explode.

All in all, in order to ensure the normal output power of the battery and extend the battery cycle life, the battery must be thermally managed-to maintain the normal operating temperature of the battery and improve the overall performance of electric vehicles in low temperature environments. It is necessary to meet the warming and heat preservation of the cold season. It is also necessary to ensure that the power lithium battery of an electric vehicle cools and dissipates in a hot environment.

Application content

The technical problem to be solved by this application is to design a device for heat dissipation at high temperature and heat preservation at low temperature.

In order to solve the above technical problems, the technical solution adopted in this application is: a plate-type heating and cooling heat conduction device, including a heating and cooling heat conduction member, the heating and cooling heat conduction member consists of a heat exchange plate and a heat exchange plate attached to one side of the heat exchange plate It is composed of infrared heating film, and the heat exchange plate is provided with a first diversion cavity for loading graphene fluid medium.

Further, it also includes a radiator, the radiator is provided with a second diversion cavity for loading the graphene fluid medium; the first diversion cavity is provided with a first liquid inlet and a first liquid outlet, The second diversion cavity is provided with a second liquid inlet and a second liquid outlet; the first liquid outlet is connected to the second liquid inlet, and the second liquid outlet is connected to the first liquid outlet. A liquid inlet connection.

Further, a circulating pump is also connected between the second liquid outlet and the first liquid inlet.

Further, a circulation conduction valve is also provided between the circulation pump and the first liquid inlet.

Further, a liquid storage tank is also provided between the circulation pump and the circulation conduction valve.

Further, there are two heating and cooling heat conducting parts; the two first liquid outlets are connected to the second liquid inlet through a first three-way pipe; the two first liquid inlets are connected through a second The three-way pipe is connected with the circulation conduction valve.

Further, the infrared heating film, the heat exchange plate and the first diversion cavity are all rectangular, and the first diversion cavity is provided with a baffle group that restricts the graphene fluid medium from flowing in a waveform; The heat sink is a finned heat sink.

Further, the infrared heating film is composed of an infrared radiation generating layer and an insulating layer that wraps the infrared radiation generating layer; the infrared radiation generating layer is composed of carbon black or micro-nano graphite powder or carbon nanofiber or carbon nanotube or Made of graphene material; the heat exchange plate is made of aluminum; the graphene fluid medium is composed of graphene and dimethicone, and the mass ratio of the graphene to the dimethicone is 5- 10:90-95.

A temperature-controllable lithium battery pack includes a lithium battery pack and a plate-type heating and cooling heat conduction device. The plate-type heating and cooling heat conduction device is connected to the lithium battery pack through the heating and cooling heat conduction member.

Further, the lithium battery cell of the lithium battery pack is composed of at least two laminated sheets, and the edge of each layer of the laminated sheet is connected with the infrared heating film of the heating and cooling heat conducting member; the lithium battery pack is located at two Between the heating and cooling heat conducting parts.

The beneficial effect of the present application is that in a low temperature environment, the infrared heating film is energized and generates heat to heat the objects in contact with it. In a high-temperature environment, the infrared heating film stops energizing, and the heat generated by the object itself is transferred to the graphene fluid medium through thermal conduction. The flow of graphene fluid medium takes away heat to achieve the purpose of cooling the object. The temperature control of the object is achieved through heating and heat conduction, ensuring that the object is not affected by environmental changes and performs its original function.

Description of the drawings

The specific structure of the application is detailed below in conjunction with the drawings

FIG. 1 is a schematic diagram of the structure connection of a temperature-controllable lithium battery pack adopting a plate-type heating and cooling heat conduction device of the application;

2 is a detailed cross-sectional structure diagram of the heating and cooling heat-conducting component of the application and a schematic diagram of graphene fluid flow;

Fig. 3 is a detailed side view of the heating and cooling heat conducting member of the application;

Figure 4 is a detailed diagram of the lithium battery structure of the application;

Among them, 1- heating and cooling heat conduction element, 101- first liquid inlet, 102- first liquid outlet, 103- first diversion cavity, 104- baffle group, 105- heat exchange plate, 106- infrared heating Membrane; 2- radiator, 201- second liquid inlet, 202- second liquid outlet; 3- circulation pump; 4- circulation pilot valve; 5- liquid storage tank; 6-lithium battery, 601- lamination , 602- battery shell; 7- first three-way pipe fitting; 8- second three-way pipe fitting; 9- third three-way pipe fitting; 10- tank valve; 11- tightening hoop.

detailed description

The most critical idea of the application is to set the infrared heating film to heat up uniformly, and set the heat exchange plate to quickly remove excess heat.

In order to further discuss the feasibility of the application concept, specific implementations of the technical content, structural features, objectives and effects achieved in this application are combined with the drawings to explain in detail.

Please refer to Figure 1, Figure 2 and Figure 3, a plate-type heating and cooling heat conduction device, including a heating and cooling heat conduction member 1, the heating and cooling heat conduction member 1 is composed of a heat exchange plate 105 and attached to one side of the heat exchange plate 105 The infrared heating film 106 is composed of an infrared heating film 106, and the heat exchange plate 105 is provided with a first diversion cavity 103 for loading a graphene fluid medium. In a low temperature environment, the infrared heating film 106 is energized and generates heat to heat the objects in contact with it. The infrared radiation generated by the infrared heating film 106 forms a planar heat source by uniform radiation on the film surface, and is uniformly heated by the area covered by the planar radiation. These substances covered by the planar radiation absorb the infrared radiation to produce a temperature increase effect. In a high temperature environment, the infrared heating film 106 stops being energized, and the heat generated by the object itself is transferred to the graphene fluid medium through thermal conduction. The flow of graphene fluid medium takes away heat to achieve the purpose of cooling the object. The temperature control of the object is achieved through heating and heat conduction, ensuring that the object is not affected by environmental changes and performs its original function.

Further, it also includes a radiator 2, the radiator 2 is provided with a second diversion cavity for loading graphene fluid medium; the first diversion cavity 103 is provided with a first liquid inlet 101 and a first The liquid outlet 102, the second diversion cavity is provided with a second liquid inlet 201 and a second liquid outlet 202; the first liquid outlet 102 is connected to the second liquid inlet 201, the The second liquid outlet 202 is connected to the first liquid inlet 101. The first diversion cavity 103, the first liquid outlet 102, the second liquid inlet 201, the second diversion cavity, the second liquid outlet 202, the first liquid inlet 101, the first diversion cavity 103 Connected in sequence, so that the graphene fluid medium circulates between the first diversion cavity 103 and the second diversion cavity, that is, the heat absorbed by the graphene fluid medium in the first diversion cavity 103 follows the graphene fluid medium It flows into the second diversion cavity and is transferred to the radiator 2. The radiator 2 dissipates heat, and the cooled graphene fluid medium circulates back to the first diversion cavity 103 again to take away more heat, so as to achieve continuous cooling of the object.

Further, a circulating pump 3 is also connected between the second liquid outlet 202 and the first liquid inlet 101. The circulating pump 3 drives the graphene fluid medium to accelerate the flow and accelerate the heat dissipation speed.

Further, a circulation conduction valve 4 is also provided between the circulation pump 3 and the first liquid inlet 101. In a high temperature environment, the circulation conduction valve 4 is opened, and the graphene fluid medium circulates between the first diversion cavity 103 and the second diversion cavity. In a low temperature environment, the circulating pilot valve 4 is closed, and the graphene fluid medium without relatively low temperature enters the first diversion cavity 103 again to take away more object heat or heat generated by the infrared heating film 106, reducing heat loss .

Further, a liquid storage tank 5 is further provided between the circulation pump 3 and the circulation conduction valve 4. The circulating pump 3 and the circulating pilot valve 4 are connected to the liquid storage tank 5 through a third three-way pipe 9. A tank valve 10 is also provided between the third three-way pipe 9 and the liquid storage tank 5. Both the tank inlet valve 10 and the circulation pilot valve 4 are solenoid valves. The fluid inlet and outlet of the liquid storage tank 5 are arranged at the bottom of the tank body, and the position of the tank body is higher than the position of the circulation pipeline. In a low temperature environment, when the object needs to be heated, the circulation pilot valve 4 is closed, the tank valve 10 is opened, and the circulation pump 3 transports the graphite fluid medium on the circulation pipeline into the storage tank 5. After the delivery is completed, the tank inlet valve 10 is closed, and the infrared heating film 106 is energized and heated. At this time, the first diversion cavity 103 and the second diversion cavity are both cavities, and the air in the cavity is relatively static. In a cavity where the air is relatively static, the thermal conductivity of air temperature "zero" ℃ is 0.024W/m·℃, and the thermal conductivity of air temperature "100" ℃ is 0.031W/m·℃. That is, when the infrared heating film 106 is heated, the heat dissipation to the outside by heating and cooling the heat-conducting member 1 can be ignored. When the temperature is too high and the object needs to be cooled, the tank valve 10 is opened, and the graphene fluid medium in the liquid storage tank 5 flows into the circulation pipeline again by the action of the liquid level difference and its own gravity. After the tank inlet valve 10 is closed, the circulation conduction valve 4 is opened, and then the circulation pump 3 is opened to enter a cooling state.

Further, there are two heating and cooling heat conducting parts 1; two first liquid outlets 102 are connected to the second liquid inlet 201 through a first three-way pipe 7; two first liquid inlets The port 101 is connected to the circulation conduction valve 4 through a second three-way pipe 8. Two heating and cooling heat-conducting parts 1 are provided to increase the heating and cooling area, and realize the rapid cooling and heating of the three-dimensional object. The two heating and cooling heat-conducting parts 1 are connected by the first three-way pipe fitting 7 and the second three-way pipe fitting 8, and share the radiator 2, the circulation pump 3, the liquid storage tank 5 and the circulation conduction valve 4. Even using a small number of components to achieve better heat dissipation and heating effects.

Further, the infrared heating film 106, the heat exchange plate 105, and the first diversion cavity 103 are all rectangular, and the first diversion cavity 103 is provided with a wave-like flow restricting graphene fluid medium. The baffle set 104; the radiator 2 is a finned radiator. The infrared heating film 106, the heat exchange plate 105, and the first diversion cavity 103 are all rectangular, that is, the heating and cooling heat conducting member 1 is rectangular, which is convenient for being close to the plane of a regular object to dissipate heat or heat. Since the heating and cooling heat conduction element 1 has a large plane and a small circulation pipeline, in order to ensure that the graphene fluid medium flows uniformly in the first diversion cavity 103, that is, to increase the effective area of heat dissipation, the baffle set 104 is set to make the graphene fluid medium appear Waves flow. As shown by the arrow in Figure 2. The finned heat sink has a large heat dissipation area, which is beneficial to quickly dissipate the heat of the graphene fluid medium in the second diversion cavity. The finned radiator is made of aluminum foil, the thermal conductivity of aluminum is 230W/m·℃, the density is small, and the machining performance is superior.

Further, the infrared heating film 106 is composed of an infrared radiation generating layer and an insulating layer wrapping the infrared radiation generating layer; the infrared radiation generating layer is composed of carbon black or micro-nano graphite powder or carbon nanofibers or carbon nanotubes Or graphene material; the heat exchange plate 105 is made of aluminum; the graphene fluid medium is composed of graphene and dimethyl silicone oil, and the mass ratio of the graphene to the dimethyl silicone oil is 5 -10:90 -95. The insulating layer wraps the infrared radiation generating layer to avoid leakage. The thickness of the infrared radiation generating layer can be 80 μm or 100 μm or 120 μm. Preferably, the mass ratio between the graphene and the simethicone is: graphene: simethicone=5:95. The graphene fluid medium composed of graphene and dimethyl silicone oil has high thermal conductivity, that is, excellent thermal conductivity, but it has heat resistance, cold resistance, water resistance, and has low surface tension, small viscosity change with temperature, and stable chemical properties , Harmless to the human body. The graphene fluid medium can be used for a long time under the environment of -50℃～200℃. Graphene is a two-dimensional nanomaterial with a resistivity of about 10-6Ω·cm, lower than copper or silver, and a thermal conductivity of 5300W/m·℃, which is 14 times higher than the thermal conductivity of copper, which is 377W/m·℃. The theoretical specific surface area of graphene is 2630m ² /g. When it is uniformly dispersed in dimethyl silicone oil, it can form a better thermal conductivity network. Therefore, in a low temperature environment, when the infrared heating film 106 is heated, the graphene fluid medium in the first diversion cavity 103 is transferred to the storage tank 5 for storage, so that a cavity is formed in the first diversion cavity 103 to avoid heat The graphene fluid medium is emitted from the other side of the heating and cooling heat conducting member 1 that is not in contact with the infrared heating film 106.

Please refer to Figure 1, Figure 2 and Figure 3, a temperature-controlled lithium battery pack, including a lithium battery pack and a plate-type heating and cooling heat conduction device, the plate-type heating and cooling heat conduction device through the heating and cooling heat conduction member 1 and the lithium Battery pack connection. Placing the lithium batteries that make up the lithium battery pack neatly and regularly can form five flat planes—the side walls of the lithium battery pack. The heating and cooling heat conduction member 1 is arranged on the side wall of the lithium battery pack, and the infrared heating film 106 of the plate heating and cooling heat conduction device provides heating and heating for the lithium battery pack, so that the lithium battery pack can be used normally in cold seasons. The graphene fluid medium circulating in the first diversion cavity 103 of the heat exchange plate transfers the heat generated during charging and discharging of the lithium battery pack to the radiator 2 for dissipation. The plate-type heating and cooling heat conduction device not only ensures the safety of the lithium battery pack at high temperatures, but also heats the lithium battery pack in the cold season, so that the lithium battery pack can work normally under various complex and changing temperature environments.

When the lithium battery 6 is charged and discharged, the heat dissipation mechanism of the battery includes heat conduction, heat convection, and heat radiation. Heat conduction, there is a temperature difference between the lithium battery 6 and the object in contact with the outside. On a macro level, it transfers heat from a high temperature object to a low temperature object, and on a micro level, it performs disordered thermal movement for microscopic particles in the substance. Thermal convection. Thermal convection occurs between a fluid and another fluid or solid. The fluid moves relative to each other while taking away the surrounding heat. Heat conduction occurs at the same time of thermal convection, and thermal convection cannot exist alone. When the lithium battery 6 is charged and discharged, the temperature of the lithium battery 6 rises, and the heated lithium battery 6 exchanges heat with the surrounding air. Thermal radiation, thermodynamics theory believes that the thermal effect produced by the disordered motion of microscopic particles on the surface of the object is collectively called thermal radiation. As long as the temperature of the object is higher than the absolute "zero" ℃, it will produce radiation to the outside, and the higher the temperature, the stronger the radiation. Thermal radiation does not require a transfer medium or direct contact. The object is constantly absorbing the radiant energy of foreign objects and emitting radiant energy to the outside. The difference is the heat generated by the radiation heat exchange. The lithium battery pack, which is integrated with multiple lithium batteries 6 for electric vehicles, is arranged in a small car body with high integration, compact structure, and narrow air convection space. It is difficult to provide enough external space for the lithium battery pack. The heat transfer of thermal convection and the heat dissipation of thermal convection are difficult to be realized directly on the structure of the lithium battery pack. Compared with the use and installation environment of the power lithium battery, the installation environment is in a closed battery box. Usually the lithium battery and the battery box have a tight structure without gaps. The temperature difference between the lithium battery and the battery box is very small. The battery cooling is not obvious. Therefore, the temperature-controllable lithium battery pack is formed by combining the lithium battery pack and the plate-type heating and cooling heat conduction device, that is, the temperature-controllable lithium battery pack formed by heat conduction to dissipate heat is more suitable for electric vehicles.

Further, referring to FIG. 4, the lithium battery 6 cells of the lithium battery pack are composed of at least two laminated sheets 601, and the edge of each laminated sheet 601 is connected to the infrared heating film 106 of the heating and cooling heat conducting member 1 Connected; the lithium battery pack is located between the two heating and cooling heat conducting parts 1. The cell stack 601 of each lithium battery 6 is composed of a positive pole piece, a separator material and a negative pole piece in sequence. The positive pole piece includes a positive electrode material coating and an aluminum foil current collector, and the negative pole piece includes a negative electrode material coating and a copper foil current collector. Both the positive electrode material coating and the negative electrode material coating are mixtures of powder and binder colloid, that is, the thermal resistance coefficients of the separator, the positive electrode material coating and the negative electrode material coating are relatively large. Therefore, the lithium battery cell is composed of multiple laminated sheets 601, and the plane of the laminated sheets 601 has a large thermal resistance to external contact heat transfer. If the heating and cooling heat conducting member 1 is in contact with the laminated sheet 601, the heating and heat dissipation effects are better. difference. The edge of the laminated sheet is the cut surface of the aluminum foil current collector and the copper foil current collector. The infrared heating film 106 for heating and cooling the thermal conductive member 1 only needs to pass through a 16μm diaphragm, and the battery case 602 is connected to the edge of the laminated sheet 601, and the connections are all Without coating, the thermal resistance of the joint is small. Therefore, by contacting the battery casing 602 with an external heat source (ie, the infrared heating film 106) or a cold source (ie, the heat exchange plate 105), better heat transfer and heating or cooling and heat dissipation effects can be achieved. Heating and cooling heat conducting elements 1 are provided on the opposite edges of the laminated sheet 601 to improve the overall temperature control effect of the temperature-controllable lithium battery pack. In addition, in order to ensure the effect of heating and cooling, a binding band 11 is used to fix the heating and cooling heat conduction member 1 and the lithium battery pack together. When the lithium battery pack is scrapped, loose the tightening band 11 to replace the lithium battery pack, and the plate heating and cooling heat conduction device will continue to be used and form a new temperature-controlled battery pack with the lithium battery pack, reducing the customer's auto parts replacement cost.

In summary, the plate heating and cooling heat conduction device provided by the present application and the temperature controllable lithium battery pack using the device, the heating and cooling heat conduction element, the radiator, the circulation pump, and the circulation conduction valve are sequentially connected to make the first diversion cavity A circulating pipeline for graphene fluid medium flow is formed between the second guide cavity and the second guide cavity. In a high-temperature environment, the heating and cooling heat-conducting member transfers the heat of the lithium battery pack in contact with it to the graphene fluid medium, and the heat is transferred to the radiator along with the flow of the graphene fluid medium for dissipation. A liquid storage tank is connected between the circulation pump and the circulation conduction valve through a third three-way pipe. In a low temperature environment, the circulating pump pump transfers the graphene fluid medium on the circulating pipeline to the storage tank, so that the first diversion cavity forms a cavity to reduce the heat transfer rate, and the infrared heating film heats the lithium battery pack and its surroundings The border heats up. Through the plate heating and cooling heat conduction device, the temperature of the lithium battery pack is controllable, can be used normally in various natural temperature environments, and is suitable for use as auto parts.

Here, the first and second... only represent the distinction between their names, and do not represent any difference in their importance and position.

The above are only examples of this application, and do not limit the scope of this application. Any equivalent structure or equivalent process transformation made using the content of the description and drawings of this application, or directly or indirectly applied to other related technologies In the same way, all fields are included in the scope of patent protection of this application.

Summary of the invention

technical problem

The solution to the problem

The beneficial effects of the invention

Claims (10)

1. A plate-type heating and cooling heat conduction device, which is characterized in that it comprises a heating and cooling heat conduction element, which is composed of a heat exchange plate and an infrared heating film attached to one side of the heat exchange plate. A first diversion cavity for loading graphene fluid medium is provided.
2. The plate heating and cooling heat conduction device of claim 1, further comprising a radiator, the radiator is provided with a second diversion cavity for loading graphene fluid medium; the first diversion cavity is provided There is a first liquid inlet and a first liquid outlet, the second diversion cavity is provided with a second liquid inlet and a second liquid outlet; the first liquid outlet and the second liquid inlet Connected, the second liquid outlet is connected with the first liquid inlet.
3. The plate heating and cooling heat conduction device according to claim 2, wherein a circulating pump is also connected between the second liquid outlet and the first liquid inlet.
4. The plate-type heating and cooling heat conduction device according to claim 3, wherein a circulation conduction valve is further provided between the circulation pump and the first liquid inlet.
5. The plate heating and cooling heat conduction device according to claim 4, wherein a liquid storage tank is also provided between the circulation pump and the circulation conduction valve.
6. The plate heating and cooling heat conduction device of claim 5, wherein there are two heating and cooling heat conduction members; the two first liquid outlets are connected to the second liquid inlet through a first three-way pipe ; The two first liquid inlets are connected to the circulation pilot valve through a second three-way pipe.
7. The plate heating and cooling heat conduction device according to any one of claims 1 to 6, wherein the infrared heating film, the heat exchange plate and the first diversion cavity are all rectangular, and the first diversion cavity A group of baffles that restrict the flow of the graphene fluid medium in a waveform is arranged in the cavity.
8. The plate heating and cooling heat conduction device according to claim 7, wherein the infrared heating film is composed of an infrared radiation generating layer and an insulating layer that wraps the infrared radiation generating layer; the infrared radiation generating layer is made of carbon black or micro Nano graphite powder or carbon nanofiber or carbon nanotube or graphene material; the heat exchange plate is made of aluminum; the graphene fluid medium is composed of graphene and dimethyl silicone oil, and the graphene The mass ratio to the dimethyl silicone oil is 5-10:90-95.
9. A temperature-controllable lithium battery pack, comprising a lithium battery pack, characterized in that it further comprises the plate-type heating and cooling heat conduction device according to any one of claims 1 to 8, wherein the plate-type heating and cooling heat conduction device conducts heat through the heating and cooling Connected to the lithium battery pack.
10. The temperature-controllable lithium battery pack according to claim 9, wherein the lithium battery cell of the lithium battery pack is composed of at least two laminated sheets, and the edge of each layer of the laminated sheet is connected to the heating and cooling heat conducting member. The infrared heating film is connected; the lithium battery pack is located between the two heating and cooling heat conducting parts.

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