Power battery cooling device

Abstract

The invention discloses a power battery cooling device, and particularly relates to the technical field of power battery cooling, the power battery cooling device comprises a heat conduction bottom plate, a plurality of micro-channel heat exchange plates and a spray valve, the plurality of micro-channel heat exchange plates are uniformly distributed along the long edge direction of the heat conduction bottom plate and are fixedly connected with the heat conduction bottom plate; a containing cavity for containing a battery single body is formed between every two adjacent micro-channel heat exchange plates, a cooling water inlet channel and a cooling water outlet channel which are communicated with micro-channels in the micro-channel heat exchange plates are formed in the heat conduction bottom plate, and flow disturbing pieces are distributed in the micro-channels. The two side faces, attached to the battery single bodies, of the micro-channel heat exchange plate are each provided with a water spraying opening communicated with the micro-channel, and when the temperature of the battery single bodies reaches the melting point of a water spraying valve for blocking the water spraying openings, cooling water in the micro-channel can flow to the containing cavity through the water spraying openings. The power battery can be uniformly and quickly cooled, the heat exchange efficiency is improved, the propagation of thermal runaway of the battery pack is effectively delayed, and the loss is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power battery cooling, and in particular to a power battery cooling device. Background Art

[0002] As the mainstream power source for pure electric vehicles, the performance and service life of lithium-ion batteries are highly sensitive to temperature. The recommended operating temperature is generally between 15°C and 35°C. When lithium-ion batteries are charged and discharged, a large amount of heat will be generated due to internal impedance and a series of electrochemical reactions. Especially when discharged at a high rate, the temperature of lithium-ion batteries usually exceeds the upper limit of the optimal operating temperature. If the battery is not cooled and dissipated in time, the long-term high-temperature operation of the battery will cause side reactions between the positive and negative electrodes and the electrolyte, releasing additional heat. The accumulation of heat can easily dissolve the diaphragm, resulting in a large-area short circuit, causing thermal runaway of the battery, and causing accidents such as fire or explosion of electric vehicles. Therefore, in order to ensure that the battery operates within an appropriate temperature range, it is crucial to reasonably design and optimize the heat dissipation structure of the thermal management system.

[0003] The battery cells inside electric vehicles are arranged closely, and the thermal management system needs to dissipate heat efficiently in a limited space. At present, the battery thermal management system based on liquid cooling is relatively mature. Due to its strong heat exchange capacity and high reliability, it has become the mainstream thermal management solution for electric vehicles. Compared with natural convection and forced convection heat exchange, the liquid cooling system has a smaller volume and higher efficiency, which can effectively reduce the battery temperature and improve temperature uniformity. However, the disadvantage is that the traditional liquid cooling plate is heavy and has a small bonding area with the battery cell. Most liquid cooling plates on the market only contact the upper and lower surfaces of the battery cell and cannot cool the sides of the battery cell, resulting in a large loss of cooling area for the battery cell.

[0004] Therefore, the use of microchannel heat exchangers as liquid cooling plates can effectively improve the above problems. Microchannel heat exchangers generally refer to heat exchangers with a hydraulic diameter of less than 1 mm. At present, they have been relatively maturely applied in industrial fields (such as refrigeration and air conditioning) and chip fields (chip heat dissipation). Compared with traditional heat exchangers, microchannel heat exchangers have obvious advantages. 1) Small size: The microchannel heat exchanger has a small diameter and is suitable for heat exchange environments with limited space, which fits the narrow space in the battery pack of electric vehicles. 2) High heat exchange efficiency: The contact area between the fluid and the microchannel heat exchanger per unit volume is much larger than that of the traditional heat exchanger, thereby enhancing the heat exchange effect. 3) Save material costs: Under the same heat exchange capacity requirements, the material consumption of the microchannel heat exchanger is much smaller than that of the conventional heat exchanger. At the same time, the smaller pipe diameter can reduce the amount of coolant or refrigerant filled, further reducing the volume and weight of the device. Chinese patent publication number CN107834126A discloses a rapid cooling device for a power battery, in which a microchannel heat exchanger is arranged at the bottom of the battery module, and the heat generated by the battery is taken away by the flow of coolant in the pipe. However, when the batteries are grouped, the sides with the largest heat flow are usually in contact with each other. The cooling effect of this cooling method is limited by the layout of the cooling pipe and the flow rate of the coolant. On the one hand, the heat exchange area of ​​each battery cell is small, and on the other hand, the battery side with a large heat flow cannot be well cooled, and the temperature uniformity of the battery is poor. The heat generated by each battery cell cannot be dissipated in time, which will cause heat accumulation and easy thermal runaway propagation. The present invention can not only achieve rapid and balanced cooling of the power battery, but also avoid the heavy weight of the water-cooled plate cooling method. Once the coolant leaks, it will cause the battery to short-circuit, or even catch fire and explode. In addition, the traditional microchannel heat exchanger has a simple structure, a single flow channel cross-sectional shape, and a low heat dissipation efficiency. It often cannot achieve uniform and rapid cooling of the power battery, and cannot effectively block the propagation of thermal runaway in the battery pack. Summary of the invention

[0005] The purpose of the present invention is to provide a power battery cooling device to solve the problems existing in the above-mentioned prior art, which can evenly and quickly cool the power battery, improve the heat exchange efficiency, effectively delay the propagation of thermal runaway of the battery pack, and reduce losses.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a power battery cooling device, comprising a heat-conducting base plate, a plurality of microchannel heat exchange plates and a spray valve, wherein the plurality of microchannel heat exchange plates are evenly distributed along the long side direction of the heat-conducting base plate and are fixedly connected to the heat-conducting base plate, and a receiving cavity for receiving a battery cell is formed between adjacent microchannel heat exchange plates, a cooling water inlet channel and a cooling water outlet channel are respectively arranged along two long sides inside the heat-conducting base plate, a microchannel is arranged inside the microchannel heat exchange plate, an inlet of the microchannel is connected and communicated with the cooling water inlet channel, an outlet of the microchannel is connected and communicated with the cooling water outlet channel, a spoiler is arranged inside the microchannel, water spray outlets are arranged on two sides of the microchannel heat exchange plate which are attached to the battery cell, the water spray outlets are communicated with the microchannels, the water spray outlets are blocked by the water spray valve, and when the temperature of the battery cell reaches the melting point of the water spray valve, the cooling water in the microchannel can flow to the receiving cavity through the water spray outlet.

[0008] Preferably, the microchannel is a serpentine channel.

[0009] Preferably, the cross-sectional shape of the microchannel is circular, elliptical or polygonal.

[0010] Preferably, the equivalent diameter of the microchannel is 10 μm-1000 μm.

[0011] Preferably, the cross-sectional shape of the spoiler is corrugated, teardrop-shaped or polygonal.

[0012] Preferably, a plurality of equidistant annular grooves are formed on the inner side wall of the microchannel, and the cross-sectional shape of the annular grooves is semicircular, arc-shaped or polygonal.

[0013] Preferably, a fusible alloy is provided inside the water spray valve.

[0014] Preferably, the water spray port is arranged at one end of the microchannel heat exchange plate close to the heat conductive bottom plate.

[0015] Compared with the prior art, the present invention has achieved the following technical effects:

[0016] The present invention provides a power battery cooling device, wherein the microchannels of the microchannel heat exchange plate are connected to the cooling water channels of the heat conductive bottom plate, and an accommodating cavity for accommodating battery cells is formed between adjacent microchannel heat exchange plates. The largest side of the battery cell is in direct and close contact with the heat exchange surface of the microchannel heat exchange plate, which can increase the heat exchange area of ​​each battery cell, enable the largest side of the battery with a large heat flow to be well cooled, improve the temperature uniformity of the battery, and promptly dissipate the heat generated by each battery cell to avoid heat accumulation and thermal runaway propagation; the spoiler arranged in the microchannel can not only It can increase the convective heat transfer area of ​​the microchannel and accelerate the generation of secondary flow and vortex by the cooling water, thereby disturbing the flow state of the cooling water and continuously destroying the fluid boundary layer, thereby effectively reducing the thermal resistance generated by the convective heat transfer process and improving the heat transfer efficiency of the microchannel; when the temperature of the battery cell reaches the melting point of the water spray valve, that is, when the temperature of the battery cell in the battery pack is too high and thermal runaway occurs, the cooling water in the microchannel can flow to the accommodating cavity through the water spray port, and the cooling water is sprayed to the side of the battery cell to cool the battery cell, which can delay the propagation of thermal runaway of the battery pack and reduce losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic structural diagram of the power battery cooling device of the present invention;

[0019] Figure 2 A schematic diagram of the bending of the microchannel of the power battery cooling device of the present invention;

[0020] Figure 3 A partial cross-sectional view of a microchannel heat exchange plate having a triangular cross-sectional shape of a microchannel;

[0021] Figure 4 A partial cross-sectional view of a microchannel heat exchange plate having a microchannel with a diamond-shaped cross-sectional shape;

[0022] Figure 5 A partial cross-sectional view of a microchannel heat exchange plate having a trapezoidal cross-sectional shape of the microchannel;

[0023] Figure 6 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the microchannel is circular;

[0024] Figure 7 A partial cross-sectional view of a microchannel heat exchange plate having an elliptical cross-sectional shape of a microchannel;

[0025] Figure 8 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the spoiler is a triangle;

[0026] Fig. 9 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the spoiler is rectangular;

[0027] Fig.10 A partial cross-sectional view of a microchannel heat exchange plate having a spoiler with a diamond-shaped cross-sectional shape;

[0028] Fig.11 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the spoiler is a water drop shape;

[0029] Fig.12 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the annular groove is triangular;

[0030] Fig.13 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the annular groove is rectangular;

[0031] Fig.14 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the annular groove is a trapezoid;

[0032] Fig.15 A partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the annular groove is semicircular;

[0033] Fig.16 It is a partial cross-sectional view of a microchannel heat exchange plate in which the cross-sectional shape of the annular groove is an arc shape.

[0034] In the figure: 1-heat-conducting bottom plate; 2-microchannel heat exchange plate; 3-water spray valve; 4-cooling water inlet channel; 5-cooling water outlet channel; 6-microchannel; 7-battery cell; 8-spoiler; 9-annular groove. DETAILED DESCRIPTION

[0035] 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.

[0036] The purpose of the present invention is to provide a power battery cooling device to solve the problems existing in the above-mentioned prior art, which can evenly and quickly cool the power battery, improve the heat exchange efficiency, effectively delay the propagation of thermal runaway of the battery pack, and reduce losses.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] The present invention provides a power battery cooling device, such as Figure 1 As shown, it includes a heat-conducting base plate 1, a plurality of microchannel heat exchange plates 2 and a spray valve. The plurality of microchannel heat exchange plates 2 are evenly distributed along the long side direction of the heat-conducting base plate 1 and are fixedly connected to the heat-conducting base plate 1. An accommodating cavity for accommodating a battery cell 7 is formed between adjacent microchannel heat exchange plates 2. A cooling water inlet channel 4 and a cooling water outlet channel 5 are respectively arranged along the two long sides inside the heat-conducting base plate 1. A microchannel 6 is arranged inside the microchannel heat exchange plate 2. The inlet of the microchannel 6 is connected and communicated with the cooling water inlet channel 4, and the outlet of the microchannel 6 is connected and communicated with the cooling water outlet channel 5. A spoiler 8 is arranged in the microchannel 6. Water spray outlets are opened on the two sides where the microchannel heat exchange plate 2 and the battery cell 7 are attached. The water spray outlets are connected with the microchannel 6 and are blocked by the water spray valve 3. When the temperature of the battery cell 7 reaches the melting point of the water spray valve 3, the cooling water in the microchannel 6 can flow to the accommodating cavity through the water spray outlet. The microchannel 6 of the microchannel heat exchange plate 2 is connected with the cooling water channel of the heat conductive bottom plate 1, and a receiving cavity for accommodating the battery cell 7 is formed between adjacent microchannel heat exchange plates 2. The largest side of the battery cell 7 is in direct and close contact with the heat exchange surface of the microchannel heat exchange plate 2, which can increase the heat exchange area of ​​each battery cell 7, and can make the largest side of the battery with a large heat flow be well cooled, improve the temperature uniformity of the battery, and dissipate the heat generated by each battery cell 7 in time to avoid heat accumulation and thermal runaway propagation; the spoiler 8 arranged in the microchannel 6 can not only increase the microchannel The convection heat exchange area of ​​6 can also accelerate the cooling water to generate secondary flow and vortex, thereby disturbing the flow state of the cooling water, continuously destroying the fluid boundary layer, and effectively reducing the thermal resistance generated by the convection heat exchange process, and improving the heat exchange efficiency of the microchannel 6; when the temperature of the battery cell 7 reaches the melting point of the water spray valve 3, that is, when the temperature of the battery cell 7 in the battery pack is too high and thermal runaway occurs, the cooling water in the microchannel 6 can flow to the accommodating cavity through the water spray port, and the cooling water is sprayed to the side of the battery cell 7 to cool the battery cell 7, which can delay the spread of thermal runaway of the battery pack and reduce losses. The volume energy density of the battery pack can be significantly improved while ensuring the safety of the battery pack.

[0039] It is further preferred in the embodiment of the present invention that Figure 2As shown, the microchannel 6 is a serpentine channel, which first extends along the height direction of the microchannel heat exchange plate 2 to the top surface of the microchannel heat exchange plate 2, then extends along the length, and then returns to the bottom surface of the microchannel heat exchange plate 2, and finally detours to the outlet at the other end, which can effectively increase the heat exchange area between the cooling water and the microchannel heat exchange plate 2, thereby improving the utilization rate of the cooling water and reducing the operating cost of the cooling device.

[0040] It is further preferred in the embodiment of the present invention that Figure 3-7 As shown, the cross-sectional shape of the microchannel 6 is circular, elliptical or polygonal. Preferably, the polygon is a triangle, rhombus, trapezoid or other polygon. By changing the shape of the microchannel, the flow pattern in the microchannel can be changed, so that the heat transfer efficiency is significantly improved; the equivalent diameter of the microchannel 6 is 10μm-1000μm, which can ensure the heat exchange area between the cooling water and the heat exchange plate 2 of the microchannel 6.

[0041] It is further preferred in the embodiment of the present invention that Figure 8-11 As shown, the cross-sectional shape of the spoiler 8 is corrugated, drop-shaped or polygonal. Preferably, the polygon is a regular polygon such as a triangle, rectangle, rhombus, etc. The spoiler 8 can cause the cooling water to generate a longitudinal vortex moving along the mainstream direction after the turbulence. The longitudinal vortex can continuously affect the disturbance of the cooling water in the microchannel 6, thereby improving the heat transfer performance of the microchannel 6.

[0042] It is further preferred in the embodiment of the present invention that Figure 12-16 As shown, a plurality of equidistant annular grooves 9 are provided on the inner wall of the microchannel 6, and the cross-sectional shape of the annular grooves 9 is semicircular, arc-shaped or polygonal. Preferably, the polygon is a triangle, rectangle, trapezoid or other polygon, which can generate local rotating transverse vortices after the cooling water is disturbed. The transverse vortices can affect the local cooling water disturbance in the microchannel 6, thereby improving the heat transfer performance of the microchannel 6.

[0043] It is further preferred in the embodiment of the present invention that a fusible alloy is provided inside the water spray valve 3 .

[0044] In the embodiment of the present invention, it is further preferred that the water spray port is arranged at one end of the microchannel heat exchange plate 2 close to the heat conductive base plate 1, which is closer to the water inlet and outlet of the microchannel heat exchange plate, so as to reduce the energy required for turning or splitting the water flow during the spraying process, making the water flow easier to spray out.

[0045] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A power battery cooling device, characterized in that: It comprises a heat-conducting base plate, a plurality of microchannel heat exchange plates and a spray valve. The plurality of microchannel heat exchange plates are evenly distributed along the long side direction of the heat-conducting base plate and are fixedly connected to the heat-conducting base plate. A receiving cavity for receiving a battery cell is formed between adjacent microchannel heat exchange plates. A cooling water inlet channel and a cooling water outlet channel are respectively arranged along two long sides inside the heat-conducting base plate. A microchannel is arranged inside the microchannel heat exchange plate. The inlet of the microchannel is connected and communicated with the cooling water inlet channel, and the outlet of the microchannel is connected and communicated with the cooling water outlet channel. A spoiler is arranged in the microchannel. Water spray outlets are arranged on two sides of the microchannel heat exchange plate which are attached to the battery cell. The water spray outlets are communicated with the microchannels. The water spray outlets are blocked by the water spray valve. When the temperature of the battery cell reaches the melting point of the water spray valve, the cooling water in the microchannel can flow to the receiving cavity through the water spray outlet.

2. The power battery cooling device according to claim 1, characterized in that: The microchannel is a serpentine channel.

3. The power battery cooling device according to claim 1, characterized in that: The cross-sectional shape of the microchannel is circular, elliptical or polygonal.

4. The power battery cooling device according to claim 1, characterized in that: The equivalent diameter of the microchannel is 10 μm-1000 μm.

5. The power battery cooling device according to claim 1, characterized in that: The cross-sectional shape of the spoiler is a corrugated shape, a teardrop shape or a polygonal shape.

6. The power battery cooling device according to claim 1, characterized in that: A plurality of equally spaced annular grooves are provided on the inner side wall of the microchannel, and the cross-sectional shape of the annular grooves is semicircular, arc-shaped or polygonal.

7. The power battery cooling device according to claim 1, characterized in that: A fusible alloy is arranged inside the water spray valve.

8. The power battery cooling device according to claim 1, characterized in that: The water spray port is arranged at one end of the microchannel heat exchange plate close to the heat conduction bottom plate.

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