CN205646054U - Power battery heat radiation structure - Google Patents

Abstract

A heat dissipation structure for a power battery, in which several cylindrical batteries are vertically arranged at intervals in the battery pack box with the opening upward, near the top of the battery, and an upper insulating positioning plate is arranged in the battery pack box, and the upper insulating positioning plate is tightly sleeved on the battery. Between the bottom and the bottom of the battery pack case, there is a gasket to cushion the lower insulating plate, and a thermal diffusion plate is arranged between the upper insulating positioning plate and the buffer lower insulating plate. The outer edge of the thermal diffusion plate is close to the side wall of the battery pack box. A through-hole corresponding to the battery is opened on the top. The through-hole has an enlarged thermal diffuser, which is tightly covered on the outer wall of the battery. The interface heat-conducting material layer is filled between the two, and several heat-conducting columns are arranged at intervals around the battery. The upper and lower ends of the heat-conducting column are respectively In close contact with the thermal diffusion plate and the battery pack box, the phase change material layer or thermoplastic potting material layer is filled under the thermal diffusion plate. The device has excellent heat transfer enhancement effect, better heat dissipation effect, more uniform temperature distribution, compact shape and simple structure, and is suitable for power battery systems.

Description

A power battery cooling structure

technical field

The utility model relates to the technical field of power battery cooling, in particular to a composite heat dissipation device with a heat diffusion plate and a heat conduction column.

Background technique

Power batteries such as lithium-ion batteries have high energy density, small size, and long cycle life. They have great application potential and market in electric passenger cars and commercial vehicles. However, since the temperature rise of the lithium-ion battery during charging and discharging affects its performance and cycle life, too high temperature may even cause thermal runaway, resulting in accidents such as spontaneous combustion and explosion. The temperature of the conventional lithium cobaltate cathode material battery needs to be controlled at 50 degrees Celsius. Within, to avoid thermal runaway and fire explosion, improve safety. With the advancement of battery materials and processes, although the operating temperature of batteries using lithium iron phosphate as the positive electrode material can be raised to 60 degrees Celsius or higher, as the temperature rises further, the battery capacity decays significantly, and thermal runaway will still occur at high temperatures and fire phenomena. Therefore, the research and implementation of power lithium-ion battery heat dissipation technology is particularly urgent.

The power lithium-ion battery cooling system usually adopts air cooling to cool the battery channel. The air cooling cooling system is small in size, but the heat dissipation effect is very limited, and the battery temperature uniformity is poor; in addition, the use of phase change materials is usually paraffin material, which has the ability to absorb latent heat during the phase change process. High, small temperature rise, good chemical stability, small size, simple structure, low price and other advantages, it can reduce the temperature rise rate of the battery, ease the thermal shock, and improve the battery life and stability when applied to the power lithium-ion battery. However, phase change materials also have disadvantages such as low thermal conductivity and inability to conduct heat quickly and uniformly.

Patent 201210399617.6 discloses a battery module comprising: a plurality of prismatic battery cells; and corrugated fins defining a generally meandering shape, the corrugated fins have alternating straight segments and top segments, such that the multiple groups At least one of the battery cells is disposed in a region of the corrugated fin defined between adjacent straight segments. Although this patent has a certain heat dissipation effect, there is no special fastening mechanism for heat transfer from the power battery to the fins, resulting in large contact gaps and contact thermal resistance, and a large temperature difference in heat transfer from the center to the outside, which is not suitable for high-power power. type battery.

Patent 200910039125.4 discloses a power battery device with a phase change material cooling system, which includes screws, several battery cells, vent holes in the case cover, electrode connecting shafts, top cover of the case body, side vent holes, and a frame; The above-mentioned battery cell uses the battery as the base body, and a shell is installed on the outside; the phase change material is filled between the battery and the shell and sealed with insulating rubber; the battery box is provided with ventilation holes for heat dissipation. Although the patent alleviates the thermal impact of the battery by filling the phase change material, it does not solve the shortcomings of slow heat dissipation and insufficient temperature control caused by the low thermal conductivity of the phase change material. When the phase change material is completely melted, the latent heat absorption ends, and the low thermal conductivity actually blocks the heat dissipation speed to the battery case.

Patent 201110345442.6 discloses a solar flower radiator for LED lamps, which includes a circular heat sink and a number of heat sink fins. The heat sink fins are arranged on the outer circle of the circular heat sink. It is characterized in that it also includes heat sink ribs. A heat dissipation rib is connected between two adjacent heat dissipation fins, and the heat dissipation rib is arc-shaped. The heat sink is made of copper material. The heat dissipation fins of this patent are prepared by an extrusion process, which is relatively complicated and time-consuming, and the heat dissipation fins produced are too heavy and bulky, and cannot be used for power plants that require high weight and volume, such as automobiles. battery system.

Utility model content

The technical problem to be solved by the utility model is to provide a power battery heat dissipation structure. The device forms a heat conduction path through a thermal diffusion plate and a heat conduction column, and uses multiple heat dissipation methods such as phase change materials to absorb heat. The heat dissipation speed is fast and the heat dissipation effect is excellent. Well, the battery has good temperature uniformity during use, and the device is compact in structure and relatively light in weight, which is good for arrangement in a limited space.

The utility model is achieved through the following technical solutions:

Several cylindrical batteries are vertically arranged in the battery pack box with the opening upward;

At least one thermal diffusion plate is horizontally arranged in the battery pack box between the top and the bottom of the battery, and a through hole corresponding to the battery is opened on the thermal diffusion plate, and the inner edge of the through hole is closely covered with the outer wall of the battery;

Several heat conduction columns are arranged at intervals around the battery, and the heat conduction columns are in close contact with the thermal diffusion plate and the battery pack box.

The battery pack box is pre-processed, installed with heat conduction columns, and connected with the heat diffusion plate to form a heat conduction path from the battery cell – heat diffusion plate – heat conduction column – bottom of the battery pack box. The heat diffusion plate is tightly fitted in the middle and lower part of the battery, The height of the middle part or the upper part can prevent the top of the cylindrical battery from being overheated due to the lack of heat dissipation channels. The exterior of the battery cell is coated or wrapped with an insulating film layer to achieve electrical insulation of the exterior of the battery.

Further, the space of the battery pack box below the thermal diffusion plate is filled with a phase change material layer or a thermoplastic potting material layer. The phase change material layer is a phase change material layer containing one or more of paraffin wax, fatty acid and inorganic salt phase change materials with a phase change temperature of 30-80°C; the porous foam structure layer of the composite phase change material is high The thermally conductive foam structure layer, such as aluminum foam metal, copper foam structure layer, graphite foam structure layer, etc., has a vacancy between 70% and 98%, and the porous structure is filled with phase change materials, which has a light structure and high phase efficiency. The role of thermal conductivity of variable materials.

The thermoplastic potting material layer is a silicone or polyurethane material layer with a thermal conductivity greater than 0.2W/mK. The phase change material layer or thermoplastic potting material layer filled in the space of the battery pack box under the thermal diffusion plate has a certain heat conduction effect: the latent heat of the phase change material when melting can absorb part of the heat generated by the battery and keep the temperature constant , so as to reduce the thermal shock amplitude of the battery temperature. In addition, another part of the heat is exported through the thermal diffusion plate, the heat conduction column and the battery pack box, thereby further reducing the battery temperature; thermoplastic potting materials usually have heat conduction fillers, which can also further enhance heat conduction and reduce the battery temperature. Thermal shock. In addition, thermoplastic potting materials have good toughness and ductility, which can reduce mechanical stress and slow down mechanical shock.

Still further, the space of the battery pack box below the thermal diffusion plate is partially or completely filled with insulating and heat-conducting oil or composite insulating and heat-conducting oil with heat-conducting filler; Oil, one of ordinary synthetic oil or refined mineral oil, such as: alkylbenzene type (benzene ring type) heat transfer oil, biphenyl and biphenyl ether low-melt heat transfer oil, silicone oil, typical brands such as DowTherm of Dow Chemical Heat conduction oil, the thermal conductivity of the heat conduction filler is above 10W/mK, and the main choices include alumina, aluminum hydroxide, boron nitride, aluminum nitride, silicon carbide and similar insulating particles with heat conduction function. During the driving process of the vehicle, the combined effect of heat conduction and convection generated by the liquid vibration of the heat transfer oil is conducive to the external heat dissipation of the battery. Thermally conductive fillers further enhance heat transfer.

Still further, the inner edge of the through hole has an enlarged thermal diffuser, and the enlarged thermal diffuser tightly covers the outer wall of the battery. Enlarging the heat diffuser can increase the heat conduction area between the heat spreader plate and the battery, and improve the heat conduction efficiency.

Still further, an interface thermally conductive material layer is filled between the enlarged thermal diffuser and the battery. The interface thermally conductive material layer is a thermally conductive adhesive layer with polyurethane, silicone, epoxy resin or acrylic as the matrix and a thermal conductivity of not less than 0.2W/mK. The interface thermally conductive material layer has two functions: one is to ensure that the thermally conductive contact surface between the thermal diffuser and the battery is sufficiently enlarged, and to avoid the thermally conductive hollow belt caused by the gap formed in the local area due to processing, assembly, etc.; the other is that the interface thermally conductive material The layer can also play a sealing role to prevent the phase change material or insulating heat transfer oil, composite insulating heat transfer oil and other fillers under the thermal diffusion plate from leaking due to melting.

Still further, the through hole on the thermal diffusion plate is punched and formed, and the enlarged thermal diffuser is a right angle of 70 to 90 degrees formed on the inner edge of the through hole during stamping or a folded surface close to a right angle, and the enlarged thermal diffuser It can face upwards or downwards, and the enlarged heat diffuser naturally formed by turning the four sides into straight sides when the through hole is stamped has a simple structure and is convenient for processing.

Still further, the thermal diffusion plate is two layers arranged at intervals above and below, which are respectively located at the height positions of the middle, lower and upper parts of the battery. In order to further reduce the temperature rise and temperature gradient, the multi-layer thermal diffusion plates are connected by heat conduction columns, thereby increasing the heat conduction path of the battery to the outside, eliminating local hot spots and reducing temperature rise.

Furthermore, the heat conduction columns between the multi-layer heat diffusion plates can adopt the following connection method: the heat conduction columns are two-stage heat conduction columns arranged up and down, and the connecting end faces of the two heat conduction columns are located in the lower heat diffusion plate, The fixing bolts firmly connect the upper thermal diffusion plate and the two sections of heat conduction columns together. During installation, first fix the lower heat conduction column on the bottom of the battery pack box body, then install the lower heat diffusion plate, and then install the upper heat conduction column and the upper heat diffusion plate, which is convenient for assembly and positioning.

Still further, the through holes are arranged in a fork or in a row on the thermal diffusion plate, the heat conduction columns are arranged in a fork or in a row in the battery pack box, and the heat conduction columns are arranged in parallel with the battery at intervals. This arrangement method not only makes full use of the internal space of the battery pack box, arranges as many thermal conduction columns and batteries as possible in the limited space, and has a compact structure, and the evenly spaced arrangement of thermal conduction columns and batteries is also conducive to improving thermal conductivity .

Furthermore, the thermal diffusion plate is a metal plate with high thermal conductivity such as aluminum, copper, titanium, iron, etc., and the thickness is 0.3-3 mm; the heat conduction column is a metal cylinder with high thermal conductivity such as aluminum or copper. The material selection of the heat spreading plate and the heat conduction column not only has high heat conduction efficiency, but also is easy to process.

Still further, the thermal diffusion plate is an aluminum plate or an aluminum alloy plate, and its outer surface is covered with an oxide film layer with medium-voltage electrical insulation strength after anodic oxidation passivation treatment. The anodized aluminum or its alloys have improved hardness and wear resistance. The melting point of the hard anodized film is as high as 2320K, the breakdown voltage is as high as 2000V, and it has excellent electrical insulation.

Still further, the cross-section of the heat-conducting column is circular, square, diamond-shaped, star-shaped or other similar cross-sectional shapes with larger heat-conducting outer edges.

Furthermore, the heat conduction column and the heat diffusion plate are fixed by fixing bolts, welded or heat conduction sleeves or other connection methods that have both fixation and heat conduction, and the heat conduction column and the bottom of the battery pack box are fixed by fix bolts , or fixed by welding, or integrally formed with the bottom of the battery pack box, or fixed by other connection methods that have both fixing and heat conduction. On the one hand, it forms the heat dissipation path of battery-thermal diffusion plate-thermal conduction column-battery box bottom plate, on the other hand, it strengthens the thermal diffusion plate to improve the mechanical strength.

Furthermore, an upper insulating positioning plate is arranged in the battery pack box, and the upper insulating positioning plate is tightly sleeved on the top of the battery; the bottom of the battery and the bottom of the battery pack box are cushioned by a cushioning lower insulating plate; the battery pack box is cooled by air or liquid Cooling, the material of the battery box is metal aluminum with reinforcing ribs. An insulating plate is installed between the battery pack box and the battery to achieve electrical insulation, and, in addition to the heat conduction from the bottom of the battery to the bottom of the battery pack box through the buffer lower insulating plate, the heat conduction to the side wall of the battery pack box through the upper insulating positioning plate In addition, the ribs not only increase the mechanical strength and impact resistance of the battery pack box, but also increase the surface area of the battery box and accelerate the heat transfer on the surface of the battery pack box.

The beneficial effects of the utility model are:

1. Excellent heat transfer enhancement effect. Due to the low internal thermal conductivity and large thermal resistance of the battery, the utility model uses high thermal conductivity metal materials to make thermal diffusion plates and enlarged thermal diffusers. The thermal diffusers are closely connected with the middle or upper part of the battery, and the lower part is connected with the thermal conduction column and the battery box. Fixed connection, forming a parallel heat conduction path of battery cell-thermal diffusion plate-heat conduction column-bottom of the battery box, which reduces the thermal resistance of the battery heat dissipation, thereby solving the problem of excessive temperature at the top of the battery, and greatly reducing the maximum temperature of the battery and Temperature inhomogeneity, with excellent enhanced heat transfer effect.

2. Apply the thermal diffusion plate of the present utility model to composite cooling devices for power lithium-ion batteries, etc., and arrange a phase change material between the battery box and the thermal diffusion plate, and the phase change material absorbs heat during the phase change process to make the battery The highest temperature is kept near the melting point of the phase change, and the heat transfer to the phase change material can be accelerated through the structure of the thermal diffusion plate and the heat conduction column, thereby further reducing the temperature rise of the battery and easing the thermal shock. The porous foam structure layer adopts composite phase change materials. The foam structure materials are aluminum, copper and graphite with high thermal conductivity, and the voids are between 70% and 98%. The pore structure can be filled with phase change materials, thereby improving Heat transfer speed and keep the battery temperature at a low level. At the same time, compared with the battery system without the heat diffusion plate and the heat conduction column, the battery system with the composite heat dissipation device of the heat diffusion plate and the heat conduction column of the present utility model has a better heat dissipation effect and a more uniform temperature distribution.

3. Good impact buffering effect and low cost: The structure of the thermal diffusion plate has lower hardness. In extreme cases such as external impact, it can be bent and deformed by impact, absorbing stress to buffer the impact strength on heat-generating devices. In addition, The heat conduction path formed by the thermal diffusion plate and the heat conduction column has a compact shape, a simple structure, less material consumption and cost savings, and is suitable for a power battery system.

Description of drawings

Fig. 1 is a schematic diagram of a perspective front view structure of a preferred solution of the device.

FIG. 2 is a schematic top view of the structure of FIG. 1 (with the upper insulating plate removed).

Fig. 3 is a sectional view taken along line A-A of Fig. 2 .

Fig. 4 is a sectional view taken along line B-B of Fig. 2 .

FIG. 5 is a schematic diagram of heat conduction columns with different cross-sectional shapes, and the dotted line indicates a basic unit area.

Figures 6 to 12 show the calculation and simulation results of 18650 cylindrical batteries (18 means diameter, 65 means length, all in mm), where:

Figure 6 Simulation results: the temperature cloud map (unit: K) of the battery cell under the steady state condition without installing the thermal diffusion plate and the heat conduction column (corresponding to H=0mm);

Fig. 7 Simulation results: the temperature cloud diagram (unit: K) under the steady state condition of the battery cell with the thermal diffusion plate installed at a height of H = 30mm;

Fig. 8 Simulation results: the temperature cloud diagram (unit: K) under the steady state condition of the battery cell with the thermal diffusion plate installed at a height of H = 40mm;

Fig. 9 Simulation results: the temperature cloud map (unit: K) of the battery cell under the steady state condition of the thermal diffusion plate installation height H = 50mm;

Figure 10 Simulation results: the maximum temperature of the battery cell in the steady state corresponding to different installation heights of the thermal diffusion plate (the phase change material PCM is not filled in Figures 6 to 10);

Fig. 11 Simulation results: the temperature contour (unit: K) of a battery cell with a thermal diffusion plate installed at a height of H = 40 mm and heated for 900 seconds with the addition of a phase change material.

Fig. 12 Simulation results: the temperature cloud map (unit: K) of a battery cell with a thermal diffusion plate installed at a height of H = 50 mm and heated for 900 seconds with the addition of a phase change material.

Fig. 13 is a schematic diagram of the perspective front view structure of another preferred solution of the device

Fig. 14 is a schematic diagram of the perspective front view structure of the third preferred solution of the device

In Figures 1-5, 13-14: 1 is the battery, 2 is the thermal diffusion plate, 3 is the heat conduction column, 4 is the side wall of the battery pack box, 5 is the phase change material layer, 6 is the bottom of the battery pack box, 7 For buffering the lower insulating plate, 8 is for enlarging the thermal diffuser, 9 is for connecting the circuit, 10 is for the upper insulating positioning plate, 11 is for fixing bolts, 12 is for a heat conduction sleeve, and 20 is for filling holes.

detailed description

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

As shown in Figures 1 to 5, several cylindrical batteries 1 are vertically arranged in the battery pack box with the opening upward, and the batteries 1 can be in the shape of square columns, cylinders, or aluminum-plastic film soft packs. Near the top of the battery 1, an upper insulating plate 10 is arranged in the battery pack box, the upper insulating positioning plate 10 is tightly sleeved on the battery 1, and the lower insulating plate 7 is cushioned between the bottom of the battery 1 and the bottom plate 6 of the battery pack box.

A thermal diffusion plate 2 is arranged between the upper insulating positioning plate 10 and the buffer lower insulating plate 7. The thermal diffusion plate 2 is a metal plate with high thermal conductivity such as aluminum, copper, titanium, iron, etc., and the thickness is 0.3-3mm. 2 The outer surface has a layer of oxide film layer with electrical insulation strength after anodic oxidation passivation treatment; the outer edge of the thermal diffusion plate 2 is close to the side wall 4 of the battery pack box, and the thermal diffusion plate 2 is punched out to match the battery 1 For a corresponding through hole, the upward or downward 90-degree right-angled surface formed on the inner edge of the through hole during punching is the enlarged heat diffuser 8, and the enlarged heat diffuser 8 is tightly sheathed in the center of the battery 1. At the upper height position, increase the gap between the thermal diffuser 8 and the battery 1 and fill the interface thermally conductive material layer. The interface thermally conductive material layer is based on polyurethane, silicone, epoxy resin or acrylic, and the thermal conductivity is not less than 0.2W/mK. Adhesive adhesive layer; several heat conduction columns 3 are arranged at intervals under the heat diffusion plate 2, and the heat conduction columns 3 are metal cylinders with high thermal conductivity such as aluminum and copper; the upper ends of the heat conduction columns 3 are locked to the bottom of the heat diffusion plate 2 by fixing bolts 11, The lower end is welded and fixed on the bottom plate 6 of the battery pack box; the through holes are arranged on the thermal diffusion plate 2 in a fork or in a row, and the heat conduction columns 3 are arranged in a fork or in a row in the battery pack box, and the heat conduction columns 3 and the battery 1 are arranged in parallel at intervals.

The space of the battery pack box under the thermal diffusion plate 2 is filled with a phase change material layer 5, a porous foam structure layer of a composite phase change material, or a thermoplastic potting material layer. The phase change material layer 5 contains One or more phase change material layers in paraffin wax, fatty acid and inorganic salt phase change materials at ℃; the foam structure material of the porous foam structure layer of the composite phase change material is high thermal conductivity material aluminum, copper, graphite, The vacancy is between 70% and 98%, and its pore structure can be filled with phase change materials, which has the functions of light structure and improving heat conduction of phase change materials. Taking aluminum metal foam as an example, according to published literature (V.V.Calmidi and R.L.Mahajan, The Effective Thermal Conductivity of High Porosity Fibrous MetalFoams, ASME J.Heat Transfer, Vol.1 2 1, pp.466-471 , 1999) it can be calculated that the effective thermal conductivity of the composite material is 6.8W/mK and 0.99W/mK when the void is 70% and 98%, respectively, which are much greater than the thermal conductivity of the phase change material itself (0.2W/mK), thus accelerating the phase change. The heat absorption effect of the variable material reduces the temperature rise rate of the battery. The thermoplastic potting material layer is a silicone or polyurethane material layer with a thermal conductivity greater than 0.2W/mK, such as Dow Corning 8760 potting compound.

As shown in Figure 13, the positive poles of the batteries 1 are grouped upwards, and the battery pack box is provided with thermally conductive columns 3. In order to further reduce the temperature rise and temperature gradient, multi-layer thermal diffusion plates can be installed, which are respectively located at the height of the middle, lower and upper parts of the battery 1. Location. The heat conduction column 3 is a two-stage heat conduction column with upper and lower configurations. The connecting end faces of the two heat conduction columns are located in the lower thermal diffusion plate 2, and the fixing bolts 11 fasten the upper thermal diffusion plate and the two thermal conduction columns together. By adding the heat diffusion plate 2 and the heat conduction column 3, the outward heat conduction path of the battery is increased, local hot spots are eliminated, and the temperature rise is reduced.

As shown in Figure 14, the positive electrodes of the batteries 1 are grouped upwards, and the battery pack box is provided with a thermal diffusion plate 2 and a thermal conduction column 3. The thermal diffusion plate 2 is provided with two enlarged thermal diffusers of different sizes. The enlarged heat diffuser 8 is set on the battery, and the gap between the set and the connection can be filled with thermal conductive glue, that is, the interface heat conduction material layer. In this embodiment, the thermal diffusion plate 2 is located at the waist of the enlarged heat diffuser 8; the other is The heat conduction sleeve 12 set on the heat conduction column 3, the heat conduction sleeve 12 not only plays the role of closely connecting the heat conduction column 3 and the heat diffusion plate 2, but also plays the role of enlarging the heat diffuser to enhance heat conduction. Increase the space between the heat diffuser 8 and the heat diffusion plate 2, and connect the heat conduction sleeve 12 and the heat diffusion plate 2 through welding or new three-dimensional printing technology. The gap between the sets can be filled with heat conduction glue or partially welded to increase the interface contact area , reduce thermal resistance.

As shown in FIG. 5 , the cross section of the heat conduction column 3 can be circular, square, rhombus or star.

As shown in Figures 6 to 12, during the computer numerical simulation process, the material of the thermal diffusion plate 2, the thermal conduction column 3, and the bottom 6 of the battery pack box are all aluminum alloy 6063, the thickness of the thermal diffusion plate 2 is 1mm, and the battery model is 18650 lithium The battery (where 18 indicates a diameter of 18mm, 65 indicates a length of 65mm, and 0 indicates a cylindrical battery), the heating power simulates the heating situation under high-rate discharge, and the heating value is 4W. The bottom 6 of the battery pack box is set at a constant temperature of 298K (25 ℃).

As shown in Figure 6, when there is no thermal diffusion plate 2 and heat conduction column 3, its heat dissipation mainly depends on the heat conduction of the bottom 6 of the battery pack box and the natural convection on the side. The temperature gradient is high, the local temperature at the top of battery 1 is the highest, and the local temperature reaches 423K (150°C), and the local temperature at the bottom of battery 1 is the lowest, at 380K (because the bottom of the battery is close to the buffer lower insulation plate, so Figures 6~9 and 11~ The lower part of the light-colored dotted line filled area in 12 is the temperature gradient of the bottom insulating material, not the internal temperature difference of the battery.), the internal temperature difference of the battery is 43K.

As shown in Figures 7 to 9, when the thermal diffusion plate 2 is used, the heat from the upper part of the battery 1 can be directly dissipated to the bottom of the battery box through the thermal diffusion plate 2 and the heat conduction column 3, thereby reducing the thermal resistance of the upper part of the battery and avoiding a sudden increase in battery temperature. raised. At the same time, since each battery 1 is connected to the bottom 6 of the battery pack box to form a heat conduction path, the temperature uniformity of the battery is good, which avoids the rapid attenuation of the capacity of some batteries caused by the temperature gradient, thereby improving the overall life and service life of the battery. As shown in Figure 7, when the installation height of the thermal diffusion plate is H=30mm, the maximum temperature of the battery isotherm is 346K, the local minimum temperature of the battery is 327K, and the internal temperature difference of the battery is 19K; as shown in Figure 8, at the installation height of the thermal diffusion plate When H=40mm, the local maximum temperature of the battery is 338K, the local minimum temperature of the battery is 328K, and the internal temperature difference of the battery is 10K; The local minimum temperature is 332K, and the temperature difference inside the battery is 8K. Different installation heights of thermal diffusion plates have a significant impact on the maximum temperature of the battery and the temperature difference inside the battery. It can be seen from Figures 7 to 10 that in this example, when the installation height is 40mm, the maximum temperature of the isotherm inside the battery is 338K. is the lowest value of the local maximum temperature of the battery in the three embodiments; when the installation height is 50mm, the temperature difference inside the battery is the smallest, which is 8K.

As shown in Figures 11-12, adding phase change materials can further reduce the temperature rise. In this embodiment, paraffin is used as the phase change material, and its melting point is set at 313K (40° C.). The numerical simulation temperature nephogram based on heating for 900 s is shown in FIGS. 11-12 . The simulation results show that the maximum temperature of the battery is reduced due to the latent heat absorption effect of the phase change material. Under H=40mm, the maximum temperature of the battery isotherm is 324K, the local temperature is close to 326K, the local minimum temperature of the battery is 313K, and the internal temperature difference of the battery is 13K, which is lower than that without adding phase change materials. In the case of installation height H=30mm and adding phase change material, the local maximum temperature of the battery is 332K, the local minimum temperature of the battery is 314K, and the internal temperature difference of the battery is 18K, which shows that the installation situation of adding phase change material is better than that of H=40mm H=30mm case.

Claims (10)

1. A power battery cooling structure, characterized in that: A plurality of cylindrical batteries (1) are vertically arranged at intervals in the battery pack box with the opening upward; At least one thermal diffusion plate (2) is horizontally arranged in the battery pack box between the top and the bottom of the battery, and a through hole corresponding to the battery (1) is opened on the thermal diffusion plate (2), and the inner edge of the through hole is tightly covered with the battery ( 1) the outer wall; Several heat conduction columns (3) are arranged at intervals around the battery, and the heat conduction columns (3) are in close contact with the thermal diffusion plate (2) and the box body of the battery pack. 2. The power battery cooling structure according to claim 1, characterized in that: The space of the battery pack box below the thermal diffusion plate (2) is filled with a phase-change material layer (5), or a porous foam structure layer of a composite phase-change material, or a thermoplastic potting material layer, or insulating heat-conducting oil; The phase change material layer (5) is a paraffin, fatty acid or inorganic salt phase change material layer with a phase transition temperature of 30-80°C; The phase change material is a paraffin, fatty acid or inorganic salt phase change material with a phase change temperature of 30-80°C; The porous foam structure layer of the composite phase change material is a highly thermally conductive foam structure layer with a porosity between 70% and 98%, and the porous structure is filled with phase change materials; The thermoplastic potting material layer is a silicone or polyurethane material layer with a thermal conductivity greater than 0.2W/mK; The insulating and heat-conducting oil is an organic heat-conducting oil with a thermal conductivity greater than 0.05W/mK. 3. The power battery heat dissipation structure according to claim 1, characterized in that: the inner edge of the through hole has an enlarged thermal diffuser (8), and the enlarged thermal diffuser (8) is tightly sheathed on the battery (1) outer wall. 4. The power battery cooling structure according to claim 3, characterized in that: The interface thermally conductive material layer is filled between the enlarged thermal diffuser (8) and the battery (1); The interface thermally conductive material layer is a thermally conductive adhesive layer with a matrix of polyurethane, silicone, epoxy resin or acrylic, and a thermal conductivity of not less than 0.2W/mK. 5. The power battery heat dissipation structure according to claim 3, characterized in that: the through hole on the heat diffusion plate (2) is formed by stamping, and the enlarged heat diffuser (8) is in the through hole when stamping The 70-90 degree turning surface formed by the edge. 6. The power battery heat dissipation structure according to claim 1, characterized in that: the through holes are arranged in a fork or in a row on the thermal diffusion plate (2), and the heat conduction columns (3) are in a fork or in a row in the battery pack box. The heat conduction column (3) is arranged in parallel with the battery (1) at intervals. 7. The power battery heat dissipation structure according to claim 1, characterized in that: the thermal diffusion plate (2) is a metal plate with high thermal conductivity of aluminum, copper, titanium, or iron, with a thickness of 0.3-3 mm; (3) It is a metal cylinder with high thermal conductivity such as aluminum and copper. 8. The power battery heat dissipation structure according to claim 7, characterized in that: the thermal diffusion plate (2) is an aluminum plate or an aluminum alloy plate, and its outer surface is covered with a layer after anodic oxidation passivation treatment, which has a medium pressure Oxide film layer with electrical insulation strength. 9. The power battery heat dissipation structure according to claim 1, characterized in that: the heat conduction column (3) and the heat diffusion plate (2) are fixed by fixing bolts (11), welded or heat conduction sleeve (12 ) is fixed, and the heat conduction column (3) and the bottom of the battery pack box (6) are fixed by fixing bolts (11), or fixed by welding, or integrally formed with the bottom of the battery pack box (6). 10. The power battery heat dissipation structure according to claim 1, characterized in that: an upper insulating positioning plate (10) is arranged in the battery pack box, and the upper insulating positioning plate (10) is tightly sleeved on the top of the battery (1); the battery ( The bottom of 1) and the bottom of the battery pack case (6) are cushioned with a lower insulating plate (7); the battery pack case is cooled by air or liquid, and the battery case is made of metal aluminum with reinforcing ribs.