CN106684285A - Grating composite radiator for battery pack - Google Patents

Abstract

The invention discloses a grid-shaped composite cooling device for a battery pack, which includes a box body, and a plurality of heat-conducting grid units are arranged in the box body, and a plurality of battery cells constituting the battery pack are respectively placed in a The grid unit, and between the grid unit and the battery cells and between the box and the grid unit are filled with phase change materials or/and heat-conducting potting materials. The grid-shaped composite cooling device provided by the invention has the advantages of simple structure, low cost, uniform heat dissipation, etc., can effectively reduce the maximum temperature of the battery pack, ensure good temperature uniformity in the battery pack, has strong practicability, and has popularization and application value.

Description

A grid-like composite cooling device for battery packs

technical field

The invention relates to a grid-like composite cooling device for a battery pack, belonging to the technical field of power battery temperature control.

Background technique

In recent years, lithium-ion power batteries have gradually become the mainstream power source for electric vehicles due to their high energy density, small size, and long cycle life. In electric vehicles, multiple single lithium batteries are usually connected in series or in parallel in different forms to form a battery device to provide the required voltage or capacity. Because the temperature of the battery itself will rise during the charge and discharge process, and the higher the charge and discharge rate, the faster the temperature will rise, especially for a device composed of multiple single cells, the temperature will accumulate faster, which will affect the best performance of the battery. In serious cases, the battery will burn or even explode. Therefore, temperature control has a great influence on the performance of the battery device. Too high, too low and unbalanced temperature will affect the performance of the battery. The ideal working temperature of the lithium battery is suitable to be kept within 50-60°C. around 5°C.

In order to prevent the performance and life of the battery from being too high due to high temperature, it is necessary to install a heat dissipation system in the battery. The traditional heat dissipation system usually adopts air cooling or liquid cooling. The air-cooled heat dissipation system is small in size, but has limited heat dissipation effect, while the liquid cooling system has better effect, but has large volume, complex structure, high pump function consumption, and potential disadvantages such as leakage. Chinese patent CN201210399617.6 discloses a corrugated-fin battery module, which includes two or more battery cells and continuous corrugated fins arranged between the battery cells, and also includes a rigid radiator and an expansion unit ; wherein the structure of the corrugated fins is substantially one-piece so that fewer parts are required to form the battery module; the corrugated fins are made of a high thermal conductivity material to facilitate removal of heat generated by the battery during operation of the battery; The heat sink is provided with channels through which the liquid coolant passes, and the corrugated fins are not in direct contact with the battery cells in direct contact with the heat sink to help remove excess heat from the module; expansion units are placed along the various battery cells Between corrugated fins of generally serpentine shape to provide uniformity of cell spacing. The battery module is equipped with corrugated fins on the basis of the radiator. Although the corrugated fins can be used to enhance heat dissipation, on the one hand, the corrugated fins occupy a large volume, and the layout requires multiple components, so the structure is relatively complicated. In this invention, the contact area between the corrugated fin and the battery is quite limited, and the heat dissipation is also limited.

Phase change materials have the advantages of high absorption latent heat, small temperature rise, good chemical stability, small size, simple structure, and low price during the phase change process. Applying them to power lithium-ion batteries can reduce battery temperature rise and ease thermal shock. Improve battery life and stability. Chinese patent CN200910039125.4 discloses a power battery device with a phase change material cooling system. The battery cell is based on the battery, and a box is installed outside; the phase change material is filled between the battery and the box and sealed with insulating rubber; the battery box is provided with ventilation holes for heat dissipation. This patent fills phase-change materials around each single battery to replace the traditional heat dissipation system, which can alleviate the heat generation of the battery. However, the phase-change materials have low thermal conductivity and cannot conduct heat quickly and evenly, so the heat dissipation effect is not up to the mark. To meet the expected requirements, it is usually necessary to improve the phase change materials, and use expensive composite phase change materials.

Chinese patent CN201110457984.2 discloses a power battery cooling system based on metal foam/composite phase change material. Including single battery, battery connecting pole, phase change material, foam metal, high thermal conductivity insulating glue, battery casing, battery upper baffle, battery lower baffle; the space between the battery cell and the battery casing is filled with foam metal as the skeleton material and a composite phase change material based on a phase change material. The phase change material is poured into the metal foam, and the single battery is connected to the foam metal after pouring with high thermal conductivity insulating glue. The upper baffle of the battery and the lower battery The baffles are installed on the upper end and the lower end of the single battery respectively, and the battery connecting pole is connected with the single battery. This patent combines metal foam with traditional phase change materials to prepare a composite phase change material. Although it overcomes the defects of low thermal conductivity of traditional phase change materials, it can keep the temperature of the battery module within the ideal working range of the battery, and can Keep the temperature difference between the single cells in the module within a few degrees, but the high cost of metal foam preparation makes the cost of the composite phase change material higher, and filling the metal foam in the phase change material will limit the natural convection of the phase change material , and the structure is more complicated.

Chinese patent CN201410006737.4 discloses a lithium battery module filled with a composite phase change material, including a top cover, a casing, a sealed grid, a lithium battery, a composite phase change material, a battery holding component, a thermally conductive rib, and a battery protection plate And the self-restoring circuit protector, the composite phase change material has 2 or more phase change points. In this patent, a composite phase change material with two or more phase change points is used for heat dissipation. The first phase change point can control the battery operating temperature within an ideal range, and the second phase change point can effectively absorb the thermal runaway of the battery. heat, avoid thermal runaway, and improve the safety of the battery module. However, the patent not only has a complex structure and is difficult to install, but also has a large difference in operating temperature between the two phase change materials, and there is no description of technical characteristics such as material compatibility and use effects. It is more difficult to use, and at the same time, the operation is more complicated in the actual operation process, and the operation effect cannot be guaranteed.

Therefore, there is an urgent need to develop a cooling device with simple structure, low cost, uniform heat dissipation, which can effectively reduce the maximum temperature of the battery pack and ensure good temperature uniformity in the battery pack.

Contents of the invention

In view of the above-mentioned problems and demands in the prior art, the object of the present invention is to provide a grid-shaped composite heat sink for battery packs with simple structure, low cost and uniform heat dissipation.

To achieve the above object, the present invention adopts the following technical solutions:

A grid-shaped composite cooling device for a battery pack, including a box body, the box is provided with a number of heat-conducting grid units, and a plurality of battery cells constituting the battery pack are respectively placed in a grid unit, Moreover, phase change materials or/and heat-conducting potting materials are filled between the grid unit and the battery cells and between the box body and the grid unit.

As a preferred solution, the battery cells placed in the grid unit are in contact with one side of the grid unit.

As a further preferred solution, thermal conductive glue is provided between the battery cells and the sides of the grid unit that are in contact with them.

As a further preferred solution, a fixing rib is provided on the side of the battery cell away from the grid unit, so as to further strengthen the close contact between the battery cell and one side of the grid unit.

As a preferred solution, a sealing insulating plate is provided on the top of the box, and a perforation for the electrodes of the battery cells to pass through is provided on the top of the sealing insulating plate where the grid unit is located.

As a preferred solution, the grid unit is made of thermally conductive materials, preferably copper, aluminum, graphite and other high thermally conductive materials, and most preferably aluminum whose surface has been anodized.

As a preferred solution, each grid unit is quadrangular or hexagonal, and several grid units are connected in parallel or fork to form the whole grid.

As a preferred solution, a composite material of phase change material and lightweight porous heat-conducting material is filled between the grid unit and the battery cell, for example: phase change material composite high-density foamed aluminum alloy (95-99% void, foam hole The density is 10-100 holes per inch, that is, 10-100PPI), to enhance the thermal conductivity of the phase change material.

As a preferred solution, the height of the grid unit matches the height of the battery cell. Generally, the height of the grid unit is similar to the height of the battery cell or lower than the height of the battery. The thickness of the frame of the grid unit is 0.01-10mm .

As a preferred solution, the cross-sectional size of the grid unit is 0.01-10 mm larger than the cross-sectional size of the battery cells.

As a preferred solution, the box body is made of high-strength materials, preferably high-strength materials such as aluminum and iron, and most preferably metal aluminum.

As a preferred solution, a cooling passage is provided on the side wall and the bottom wall of the box to let in air or liquid for cooling, so as to enhance the heat dissipation effect on the battery.

As a preferred solution, the thermal conductivity of the phase change material is ≥0.2W/mK, and it is selected from any one of paraffin wax, fatty acid, and inorganic salt, preferably paraffin wax with a melting point of 30-70°C.

As a preferred solution, the heat-conducting potting material has a thermal conductivity ≥ 0.2 W/mK, and is selected from any one of polyurethane, silicone, and epoxy resin.

Compared with the prior art, the beneficial technical effect of the present invention is:

In the present invention, a plurality of grid units with high thermal conductivity are provided in the box, and a plurality of battery cells constituting the battery pack are respectively placed in a grid unit, and between the grid unit and the battery cells and between the box body and the The grid units are filled with phase-change materials or/and heat-conducting potting materials, which can effectively reduce the maximum temperature of the battery pack by using conventional phase-change materials and ensure good temperature uniformity in the battery pack. The grid units are connected to each other, which not only plays the role of strengthening the device, but also enhances the heat conduction and uniform temperature between the units. operation reliability and service life; and, compared with the existing liquid-cooled and air-cooled methods, the present invention does not need additional power consumption devices (such as liquid-cooled pumps, air-cooled compressors, etc.) The battery pack cooling device has the disadvantages of heavy weight and difficult installation, but is easy to use and has strong practicability. Compared with the prior art, it has significant progress and is of popularization and application value.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of a grid-like composite cooling device for a battery pack provided in Example 1;

FIG. 2 is a schematic top view of a grid-shaped composite heat sink for a battery pack provided in Embodiment 1;

3 is a schematic cross-sectional structural view of a grid-shaped composite heat sink for a battery pack provided in Embodiment 1;

FIG. 4 is a schematic top view of a grid-shaped composite heat sink for a battery pack provided in Embodiment 2;

FIG. 5 is a schematic top view of a grid-shaped composite heat sink for a battery pack provided in Embodiment 3;

Fig. 6 is a diagram showing the variation of the maximum surface temperature of the battery packs located in different cooling devices with time;

Fig. 7 is the temperature nephogram of the cooling device that comparative example provides;

Fig. 8 is a temperature cloud diagram of the grid-shaped composite heat sink provided by Example 1.

The numbers in the figure are as follows: 1-box; 2-grid unit; 3-battery unit; 4-phase change material or heat-conducting potting material; 5-heat-conducting adhesive; -Reinforced ribs.

detailed description

The technical solutions of the present invention will be further clearly and completely described below in conjunction with the accompanying drawings and embodiments.

Example 1

As shown in Figure 1 and Figure 2: a grid-shaped composite cooling device for battery packs provided in this embodiment includes a box body 1, and a number of heat-conducting grid units 2 are arranged in the box body 1 to form a A plurality of battery cells 3 of the battery pack are respectively placed in a grid unit 2 , and phase change materials 4 are filled between the grid unit 2 and the battery cells 3 and between the box 1 and the grid unit 2 . The battery cell 3 placed in the grid unit 2 is in contact with one side of the grid unit 2, and a thermally conductive glue 5 (such as As shown in FIG. 2 , the thermal conductive adhesive can be Dow Corning EA9189 silica gel), so that the battery cell 3 and the grid unit 2 are closely connected to improve thermal conductivity.

The material of the box body 1 is metal aluminum with high strength (for example, it can be 6063 aluminum), and its height is similar to that of the battery cell 3, which can be designed as 65mm. The channel is used to pass air or liquid for cooling, so as to enhance the cooling effect on the battery.

The material of the grid unit 2 is metal aluminum with high strength and high thermal conductivity (such as 6063 aluminum), and the number of the grid unit 2 is consistent with the number of the battery cells 3, which is set to 12 in this embodiment , whose shape is set to a square.

The battery cell 3 is selected from 18650 columnar commercial lithium-ion batteries, and the phase change material 4 is selected from paraffin wax with a melting point of 41-43°C.

As shown in Figure 3: a sealing insulating plate 6 is provided on the top of the box body 1 to prevent the filled phase change material 4 from overflowing or leaking; The electrode of the battery cell 3 passes through the hole 61 , the size of the hole 61 is adapted to the size of the electrode of the battery cell 3 , so as to expose the electrode of the battery cell 3 .

Example 2

As shown in Figure 3 and Figure 4: a grid-shaped composite cooling device for battery packs provided by this embodiment includes a box body 1, and a number of heat-conducting grid units 2 are arranged in the box body 1 to form a A plurality of battery cells 3 of the battery pack are respectively placed in a grid unit 2 , and phase change materials 4 are filled between the grid unit 2 and the battery cells 3 and between the box 1 and the grid unit 2 . Wherein, the battery cell 3 is shifted to one side of the grid unit 2 and closely contacted, and the side of the battery cell 3 away from the grid unit 2 is provided with a fixed reinforcement rib 7 (as shown in FIG. 4 , the reinforcement rib can Select hard plastic) to further strengthen the close contact between the battery cells and one side of the grid unit.

The rest of the content of the grid-shaped composite cooling device described in this embodiment is the same as that described in Embodiment 1.

The grid unit 2 is made of graphite with high strength and high thermal conductivity. The number of grid units 2 is consistent with the number of battery cells 3. In this embodiment, there are 12 grid units, and their shape is set as a square.

The battery cell 3 is selected from 26650 columnar commercial lithium-ion batteries, and the phase change material 4 is selected from paraffin wax with a melting point of 50-53°C.

Example 3

As shown in FIG. 3 and FIG. 5 , the present embodiment provides a grid-shaped composite cooling device for a battery pack, which includes a box body 1, and a number of heat-conducting grid units 2 are arranged inside the box body 1. The grid unit 2 is a regular hexagon (as shown in FIG. 5 ).

The rest of the content of the grid-shaped composite cooling device described in this embodiment is the same as that described in Embodiment 1.

Example 4

Referring to Fig. 3 and Fig. 5, the present embodiment provides a grid-shaped composite cooling device for a battery pack, which includes a box body 1, and a number of heat-conducting grid units 2 are arranged inside the box body 1, forming a A plurality of battery cells 3 of the battery pack are respectively placed in a grid unit 2, and a heat-conducting potting material 4 is filled between the grid unit 2 and the battery cells 3, and a heat-conducting potting material 4 is filled between the box 1 and the grid unit 2. Both are filled with phase change material 4 . The remaining content of the grid-shaped composite heat sink in this embodiment is the same as that in Embodiment 3.

The battery cell 3 is a 26650 columnar commercial lithium-ion battery, the phase change material 4 is paraffin wax with a melting point of 50-53°C, and the heat-conducting potting material 4 is potted with silicone with a thermal conductivity of 0.6W/mK. glue.

Example 5

Referring to Fig. 3 and Fig. 5, the present embodiment provides a grid-shaped composite cooling device for a battery pack, which includes a box body 1, and a number of heat-conducting grid units 2 are arranged inside the box body 1, forming a A plurality of battery cells 3 of the battery pack are respectively placed in a grid unit 2 , and phase change materials 4 are filled between the grid unit 2 and the battery cells 3 and between the box 1 and the grid unit 2 .

The rest of the grid-shaped composite heat sink in this embodiment is the same as that in Embodiment 3, except that the battery cells 3 are not shifted to one side of the grid unit 2 .

comparative example

The cooling device of the comparative example is basically the same as that of the embodiment 1, except that the grill unit 2 is not provided in the box body 1 .

The working principle of the grid-shaped composite cooling device for the battery pack is as follows:

Since several grid units 2 with high thermal conductivity are arranged in the box body 1, a plurality of battery cells 3 constituting the battery pack are respectively placed in one grid unit 2, between the grid unit 2 and the battery cells 3 and Both the box body 1 and the grid unit 2 are filled with phase-change materials or heat-conducting potting materials 4. Therefore, when the battery pack is working in a high-power state, part of the heat generated by the battery cells 3 is directly transferred to the grid. The phase change material or heat conduction potting material 4 of the unit 2 and the battery cell 3, another part of the heat is directly transferred to the grid unit 2, and dissipated to the external environment through the box body 1, and is stored in the phase change material or heat conduction potting material 4. The part of the heat in the material 4 can be gradually transferred to the box body 1 through the high thermal conductivity grid unit 2, and finally dissipated to the external environment, so as to realize the temperature control of the battery pack and keep the temperature of the battery pack within a reasonable range.

Performance Testing

Test of average surface temperature:

Select the grid-shaped composite cooling device provided by Embodiment 1 and Embodiment 3, and the cooling device in the comparison example without grid units and only phase-change materials, and carry out numerical simulations under the same test conditions, respectively. The average surface temperature of the battery pack in the cooling device provided in Example 1, Example 3 and Comparative Example, the phase change material is paraffin wax with a melting point of 41-43°C, and the heating power of the battery pack is adjusted to 4.4W to simulate Table 1 shows the test results of numerical simulation for 15 minutes of lithium-ion battery heating during high-rate discharge.

sample comparative example Example 3 Example 1 Average battery surface temperature (°C) 60 50 48

As can be seen from Table 1: the heat dissipation device obtained by the technical solution of the present invention can make the average surface temperature of the battery pack in operation far lower than the surface average temperature of the battery pack in the heat sink without grid units, so It shows that the grid-shaped composite heat dissipation device provided by the invention can make the temperature difference inside the battery pack smaller, the heat dissipation performance is more excellent, and the temperature of the battery, especially the lithium ion battery, can be effectively reduced.

The test of the maximum surface temperature:

Select the grid-shaped composite cooling device provided in Embodiment 1, Embodiment 3, and Embodiment 5, and the cooling device provided in the comparison example without a grid unit and only have phase-change materials, and test them at different times under the same test conditions. The highest surface temperature of the battery pack within which the point is located, the specific test results are shown in Figure 6.

Fig. 6 is the change figure of the surface maximum temperature of the battery packs located in different heat sinks with time; as can be seen from the figure, with the prolongation of working time, the battery located in the heat sink (comparative example) without grid unit The highest surface temperature of the pack is much higher than the highest surface temperature of the battery pack in the grid-shaped composite cooling device provided by Embodiments 1, 3, and 5, especially higher than the side of the battery cell and the grid unit. The highest surface temperature of the battery pack that contacts (embodiment 1, 3), for example: during 900s, the highest surface temperature of the battery pack that is positioned in the heat sink (comparative example) without grid unit is up to 333K, while it is located in embodiment 1, 3 The highest surface temperatures of the battery packs in the grid-shaped composite cooling device provided were 321K and 323K, respectively, and the temperatures were reduced by 12°C and 10°C, respectively. This also shows that the grid-shaped composite heat dissipation device provided by the present invention has more excellent heat dissipation performance, and can effectively reduce the surface temperature of batteries, especially lithium-ion batteries.

Temperature cloud map test:

Select the grid-shaped composite cooling device provided in Example 1 and the cooling device provided by the comparative example without a grid unit and only have a phase change material, and measure the surface temperature of the battery at different positions in it under the same test conditions , the specific test results are shown in Figure 7 and Figure 8.

Fig. 7 is the temperature nephogram of the battery pack located in the cooling device provided by the comparative example, and the temperature unit is K; is K, and it can be seen from Figures 7 and 8 that the highest temperature difference of the battery cells in the heat sink provided by the comparative example reaches 6.4°C, while that of the battery cells in the grid-shaped composite heat sink provided by Example 1 The highest temperature difference is about 4°C (within the ideal operating temperature range of the lithium battery), and the temperature difference of the battery pack is effectively reduced by 2.4°C, which shows that the grid-shaped composite cooling device of the present invention can effectively reduce the temperature difference of the battery pack. The temperature difference is controlled within a small range.

Finally, it is necessary to point out that: the above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and any person familiar with the technical field can understand the technical scope disclosed in the present invention. Any easily conceivable changes or substitutions within the scope of the present invention shall be covered within the protection scope of the present invention.

Claims (10)

1. a kind of grid-like composite heat dissipation device for set of cells, it is characterised in that：Including casing, if being provided with the casing The grill unit of dry heat conduction, the multiple battery cells for constituting set of cells are individually positioned in a grill unit, also, in grid Phase-change material or/and heat conduction Embedding Material are filled between unit and battery cell and between casing and grill unit.

2. grid-like composite heat dissipation device according to claim 1, it is characterised in that：The battery being placed in grill unit Monomer contacts with the side of the grill unit.

3. grid-like composite heat dissipation device according to claim 2, it is characterised in that：It is in contact in battery cell Heat-conducting glue is provided between the side of grill unit.

4. the grid-like composite heat dissipation device according to Claims 2 or 3, it is characterised in that：In battery cell away from grid The sidepiece of unit is provided with fixed reinforcement.

5. grid-like composite heat dissipation device according to claim 1, it is characterised in that：It is provided with close at the top of the casing Envelope insulation board, is located at the top of grid cell in the sealed insulation plate and is provided with the perforation passed for the electrode of battery cell.

6. grid-like composite heat dissipation device according to claim 1, it is characterised in that：Grill unit and battery cell it Between fill the composite of phase-change material and light porous Heat Conduction Material.

7. grid-like composite heat dissipation device according to claim 1, it is characterised in that：Each grill unit be tetragon or Hexagon, grid entirety is formed between some grill units with in-line arrangement or fork row's connection；The material of the grill unit is to lead Hot material.

8. grid-like composite heat dissipation device according to claim 1, it is characterised in that：The sectional dimension of grill unit is than electricity Big 0.01~the 10mm of sectional dimension of pond monomer.

9. grid-like composite heat dissipation device according to claim 1, it is characterised in that：In the side wall and diapire of the casing It is provided with and is passed through the cooling duct that air or liquid are cooled down.

10. grid-like composite heat dissipation device according to claim 1, it is characterised in that：The thermal conductivity of the phase-change material >=0.2W/mK, the thermal conductivity >=0.2W/mK of the heat conduction Embedding Material.