Liquid-cooled battery pack structure with forced air cooling heat exchange function

Abstract

The utility model discloses a liquid-cooled battery pack structure with forced air cooling heat exchange, which comprises a battery pack lower shell, a cooling liquid flow channel is arranged in the battery pack lower shell, a cooling liquid inlet and a cooling liquid outlet are arranged on the end face of the battery pack lower shell, and an end plate is connected in the battery pack lower shell and parallel to the end face of the battery pack lower shell. The battery pack lower shell is matched with the end plate to accommodate and place the battery pack, a heat-conducting structural adhesive is sprayed above the battery pack, the battery pack is connected with a fixed pressing plate, and a battery pack upper cover connected with the battery pack lower shell is arranged above the fixed pressing plate; an air cooling heat exchange device is connected above the battery pack upper cover, a side plate of the battery pack lower shell is hollow, the top of the side plate of the battery pack lower shell is communicated with the air cooling heat exchange device, and a communicated bottom air inlet device is arranged at the bottom of the side plate of the battery pack lower shell. Air cooling and liquid cooling can be cooperated according to the heat dissipation requirement of the battery pack, and the service life of the battery pack is prolonged.

Description

Technical Field

[0001] This utility model belongs to the field of battery pack technology, specifically relating to a liquid-cooled battery pack structure with forced air cooling heat exchange. Background Technology

[0002] Currently, liquid cooling has become the preferred method for battery pack thermal management due to its high heat exchange efficiency and excellent stability. Liquid cooling can carry away the large amount of heat generated by the cells during high-rate charging and discharging. However, liquid cooling systems require a complete cooling system, such as water pumps, plate heat exchangers, and compressors, which consume a significant amount of the vehicle's battery pack power during operation, resulting in a reduction in the vehicle's driving range.

[0003] In some liquid-cooled battery packs that are used for long-term low-rate charging and discharging scenarios, the heat generated during charging and discharging is relatively small. Turning on the liquid cooling system wastes the vehicle's total power and reduces the vehicle's range. If it is not turned on, the temperature difference of the battery pack will be large, and some cells will be in a high-temperature state for a long time, which will accelerate the aging of cell materials and shorten the life of the overall battery pack.

[0004] As the requirements for battery pack integration increase, integrating the liquid cooling plate with the lower or upper housing of the battery pack is gradually becoming one of the mainstream choices. The material used for the integrated liquid cooling lower housing solution is generally aluminum such as Al6061, which has a thermal conductivity as high as 154W / (m·k). The increased heat loss of the battery pack to the external environment leads to poor thermal insulation performance of the battery pack, that is, the battery pack's ability to resist harsh environments such as high temperature and low temperature is relatively reduced.

[0005] Forced air cooling is simple in structure and has extremely low energy consumption. It uses a fan or blower as its driving source and air as its heat exchange medium. With the help of the natural cooling capacity of the transitional season, it can control the battery temperature at a comfortable temperature (about 20-35°C) with very low operating costs and without worrying about a series of problems caused by working fluid leakage. However, because air has a low specific heat capacity, its ability to carry cold air is limited, and it is generally used in scenarios with relatively low heat dissipation requirements.

[0006] Natural cooling has extremely low heat exchange efficiency and is only used in low-end electric vehicles. Furthermore, the overall temperature is relatively high and the temperature field is uneven during use, which leads to a decrease in the expected lifespan of the battery pack.

[0007] Existing battery packs generally only use one heat exchange method, making it difficult to balance the relationship between energy saving, heat dissipation, and environmental adaptability. Utility Model Content

[0008] The purpose of this invention is to provide a liquid-cooled battery pack structure with forced air cooling heat exchange, in which air cooling and liquid cooling can work together according to the heat dissipation needs of the battery pack, thereby extending the service life of the battery pack.

[0009] To achieve the above objectives, this utility model provides a liquid-cooled battery pack structure with forced air cooling heat exchange, including a lower battery pack housing, a coolant flow channel inside the lower battery pack housing, a coolant inlet and a coolant outlet on the end face of the lower battery pack housing, an end plate connected to the lower battery pack housing parallel to the end face of the lower battery pack housing, the lower battery pack housing and the end plate accommodate the battery pack, a thermally conductive structural adhesive is sprayed on the top of the battery pack and a fixing plate is connected thereto, and a battery pack cover connected to the lower battery pack housing is provided above the fixing plate.

[0010] A heat exchanger is connected to the top of the battery pack cover. The lower side panel of the battery pack is hollow inside, and the top of the lower side panel is connected to the heat exchanger. A bottom air intake device is connected to the bottom of the lower side panel of the battery pack.

[0011] As a further embodiment of this utility model: the air-cooled heat exchange device includes a base plate and a cover plate. The cover plate is connected above the base plate. Ventilation openings are provided on both sides of the base plate to communicate with the side plate of the lower housing of the battery pack. An exhaust port is provided on the cover plate, and a cooling fan is installed on the exhaust port. An arc-shaped rib is connected around the cooling fan on the base plate, and a gap is left between the top of the arc-shaped rib and the cover plate.

[0012] As a further embodiment of this utility model: the side plate of the lower shell of the battery pack has a rectangular cross-section, and several heat exchange fins are connected inside, which divide the rectangular cross-section into several triangular cross-sections.

[0013] As a further embodiment of this utility model: the bottom air intake device includes a trough, the top opening of the trough is connected to the side plate of the lower housing of the battery pack, a motor is connected to the outer end face of the trough, the outer side plate of the trough is a dustproof and breathable plate, and a baffle parallel to the dustproof and breathable plate is slidably connected inside the trough, the baffle is driven by the motor.

[0014] As a further embodiment of this utility model: thermally conductive silicone pads are respectively connected to the upper and lower surfaces of the battery pack cover.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. By setting thermally conductive silicone pads on the upper and lower surfaces of the battery pack cover, the thermal resistance on the heat transfer path of the battery cell is reduced, enabling the heat generated by the battery cell to be quickly conducted to the heat exchange surface of the external heat exchange device.

[0017] 2. The lower shell side plate of the battery pack is set as a vertical heat exchange channel with a cross-section of several interlaced triangles. On the one hand, it can meet the requirements of the battery pack for lightweight and structural strength. On the other hand, when the cooling fan is running, the heat exchange ribs arranged in an interlaced manner between the two lower shell side plates of the battery pack can evenly divide the airflow and increase the heat exchange area. The air from the outside environment entering from the bottom air inlet can fully exchange heat with the lower shell side plate of the battery pack before being discharged, thereby improving the heat exchange uniformity and heat exchange efficiency of the entire pack.

[0018] 3. The bottom plate of the air-cooled heat exchanger is equipped with arc-shaped ribs. The arc-shaped ribs and the cover plate form several air ducts. The air passing through the side plate of the lower shell of the battery pack is uniformly heated under the guidance of the heat exchange ribs and arc-shaped ribs. The arc-shaped ribs and the cover plate are separated, thereby cutting off the heat transfer path between the external environment and the top cover of the battery pack, so that the battery pack has good thermal insulation performance.

[0019] 4. Using a cooling fan as the power source for the air-cooled heat exchange device can enhance the convective heat transfer intensity between the external environment and the entire battery pack heat exchange surface, which is beneficial for reducing battery temperature and improving temperature uniformity among individual cells.

[0020] 5. A bottom air inlet device is installed at the bottom of the side panel of the lower casing of the battery pack. The outer side of the bottom air inlet device is a dustproof and breathable plate, which can reduce the entry of dust and large particles into the entire heat exchange channel and reduce the overall heat exchange efficiency. The bottom air inlet device is also equipped with a motor-driven baffle, which can block the dustproof and breathable plate when the air-cooling device is not in use, thereby closing the air inlet and achieving better thermal insulation performance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the liquid-cooled battery pack with forced air cooling heat exchange according to this utility model.

[0022] Figure 2 This is an exploded view of the liquid-cooled battery pack structure with forced air cooling heat exchange according to this utility model.

[0023] Figure 3 This is a partially enlarged cross-sectional view of the liquid-cooled battery pack structure with forced air cooling heat exchange according to this utility model.

[0024] Figure 4 The figure shows the change of the NTC temperature curve of the battery pack over time, which is used to verify the thermal performance of this utility model through numerical simulation.

[0025] Figure 5 The graph shows the change of NTC temperature difference within the battery pack over time, used for numerical simulation verification of the thermal performance of this utility model.

[0026] Figure 6 This is a schematic diagram of the temperature field of the battery pack used for numerical simulation verification of the thermal performance of this utility model.

[0027] In the diagram: 1. Lower housing of battery pack, 2. Coolant inlet, 3. Coolant outlet, 4. Bottom air intake device, 5. Air-cooled heat exchange device, 6. End plate, 7. Battery pack, 8. Thermally conductive structural adhesive, 9. Fixing plate, 10. Thermally conductive silicone pad, 11. Battery pack top cover, 12. Heat exchange fins.

[0028] 4.1 Motor, 4.2 Slot, 4.3 Mounting hole 1, 4.4 Fastening bolts, 4.5 Baffle, 4.6 Dustproof and breathable plate;

[0029] 5.1 Base plate, 5.2 Arc-shaped rib plate, 5.3 Cooling fan, 5.4 Cover plate, 5.5 Exhaust vent, 5.6 Mounting hole 2, 5.7 Fixing bolts. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings.

[0031] like Figure 1 and Figure 2 As shown, the liquid-cooled battery pack structure with forced air cooling heat exchange includes a lower battery pack housing 1. The lower battery pack housing 1 has a coolant flow channel. A coolant inlet 2 and a coolant outlet 3 are located on the end face of the lower battery pack housing 1. The coolant inlet 2, coolant flow channel, and coolant outlet 3 form a circulation loop to dissipate heat from the entire battery pack 7. An end plate 6 is connected parallel to the end face of the lower battery pack housing 1. The lower battery pack housing 1, in conjunction with the end plate 6, accommodates and houses the battery pack 7. Figure 2 As shown, there is a set of end plates 6. The battery pack 7 is divided into two modules by the end plates 6. Each module has aerogel attached to both ends. The number of end plates 6 can be adjusted according to actual use needs. Thermally conductive structural adhesive 8 is sprayed on the top of the battery pack 7 and a fixing plate 9 is connected to it. A battery pack cover 11 connected to the lower housing 1 of the battery pack is provided on the top of the fixing plate 9.

[0032] A forced-air cooling heat exchange device 5 is connected to the top of the battery pack cover 11. The side panel of the lower battery pack housing 1 is hollow, and the top of the side panel is connected to the forced-air cooling heat exchange device 5. The bottom of the side panel of the lower battery pack housing 1 is provided with a bottom air intake device 4. The forced-air cooling heat exchange device 5 provides power so that outside air enters through the bottom air intake device 4, passes through the hollow side panel of the lower battery pack housing 1, and is then discharged through the forced-air cooling heat exchange device 5, forming a forced-air cooling heat exchange.

[0033] To improve the effectiveness of air-cooled heat exchange, the air-cooled heat exchange device 5 further includes a base plate 5.1 and a cover plate 5.4. The cover plate 5.4 is connected above the base plate 5.1. The base plate 5.1 is connected to the lower housing 1 of the battery pack by fixing bolts 5.7. The cover plate 5.4 has a second mounting hole 5.6 for easy installation and fixing of the fixing bolts 5.7. Ventilation openings communicating with the side plates of the lower housing 1 of the battery pack are provided on both sides of the base plate 5.1. The cover plate 5.4 is provided with an exhaust port 5.5, and a cooling fan 5.3 is installed on the exhaust port 5.5. An arc-shaped rib plate 5.2 is connected around the cooling fan 5.3 on the base plate 5.1. The top of the arc-shaped rib plate 5.2 is left with a gap of 1mm-5mm between it and the cover plate 5.4 to avoid thermal or cold bridges. The lower end face of the cooling fan 5.3 has a large vertical distance from the base plate 5.1 to reduce the pressure drop of the cooling fan 5.3; the arc-shaped rib plate 5.2 mainly guides the airflow and increases the contact area with the air, thereby improving the heat exchange efficiency and heat exchange uniformity.

[0034] The air-cooled heat exchanger 5 adopts a modular design and is a square shape. Different numbers of air-cooled heat exchangers 5 can be matched according to the actual length of the battery pack, which reduces the cost of mold opening and increases versatility.

[0035] To further improve the heat exchange effect of the side plate of the lower housing 1 of the battery pack, such as... Figure 2 As shown, the side plate of the lower housing 1 of the battery pack is preferably made of 6000 series aluminum profile. The cross-section of the side plate of the lower housing 1 of the battery pack is rectangular, and several heat exchange fins 12 are connected inside, which divide the rectangular cross-section into several triangular cross-sections. The heat exchange fins 12 can divide the airflow and increase the heat exchange area, while meeting the requirements of lightweight and structural strength, and improving heat exchange performance.

[0036] In practical use, air cooling and liquid cooling need to work together. Furthermore, the bottom air intake device 4 includes a tank 4.2. The top opening of the tank 4.2 connects to the side plate of the lower housing 1 of the battery pack. A motor 4.1 is connected to the outer end face of the tank 4.2. The outer side plate of the tank 4.2 is a dustproof and breathable plate 4.6. A baffle 4.5 parallel to the dustproof and breathable plate 4.6 is slidably connected inside the tank 4.2. The baffle 4.5 is driven by the motor 4.1. The tank 4.2 is fixed to the lower housing 1 of the battery pack by fastening bolts 4.4. Mounting holes 4.3 are provided on both the baffle 4.5 and the dustproof and breathable plate 4.6 corresponding to the fastening bolts 4.4, facilitating the installation and tightening of the fastening bolts 4.4. By driving the baffle 4.5 with the motor 4.1, the air intake volume of the bottom air intake device 4 can be adjusted, thereby coordinating with the liquid cooling to adjust the heat exchange intensity as needed.

[0037] Furthermore, such as Figure 2As shown, thermally conductive silicone pads 10 are connected to the upper and lower surfaces of the battery pack cover 11, respectively. The thermally conductive silicone pads 10 can reduce the contact thermal resistance between the battery pack cover 11 and the fixing plate 9 and the base plate 5.1 of the air-cooled heat exchange device 5, thereby ensuring the air-cooled heat dissipation effect.

[0038] This invention can operate with low energy consumption and high efficiency across the entire temperature range (-20℃ to 60℃): it has good thermal insulation performance in ambient temperatures of -20℃ to 10℃, reducing the heat loss of the battery pack to the outside environment in low-temperature environments, thereby reducing the power consumption for preheating the battery pack; in environments of 10℃ to 30℃, forced air cooling heat exchange is used; in environments of 30℃ to 60℃, a liquid cooling system is used. Whether to activate forced air cooling heat exchange in this environment depends on the NTC temperature inside the battery pack and the ambient temperature. When the battery pack temperature is lower than the ambient temperature, forced air cooling heat exchange is turned off, and the bottom air intake device 4 is closed by the motor 4.1 driving the baffle 4.5 to improve the thermal insulation performance of the battery pack; when the NTC temperature is higher than the ambient temperature, forced air cooling heat exchange is activated, working together with the liquid cooling system to quickly dissipate the heat inside the battery pack to the outside, extending the service life of the battery pack 7.

[0039] The thermal performance of this invention was numerically simulated and verified using computational fluid dynamics simulation software. Under an ambient temperature of 25℃, the battery cell underwent two consecutive charge-discharge cycles at a charging rate of 0.5C. With only forced air cooling heat exchange enabled, the thermal performance was as follows: Figure 4 As shown, the final maximum battery temperature stabilized at around 29.6℃. Figure 5 As shown, the temperature difference of the NTC inside the battery pack is about 0.9℃, indicating a significant cooling effect. Under ambient temperature conditions of -20℃, when the bottom air intake device 4 is closed, the average temperature drop rate of the entire battery pack over 12 hours is 3.2℃ / h, demonstrating good thermal insulation performance. The final temperature field of the battery pack is as follows... Figure 6 As shown.

Claims

1. A liquid-cooled battery pack structure with forced air cooling heat exchange, comprising a lower housing (1) of the battery pack, wherein a coolant flow channel is provided inside the lower housing (1), and a coolant inlet (2) and a coolant outlet (3) are provided on the end face of the lower housing (1), characterized in that, An end plate (6) is connected inside the lower housing (1) of the battery pack, parallel to the end face of the lower housing (1). The lower housing (1) of the battery pack, in conjunction with the end plate (6), accommodates and places the battery pack (7). Thermally conductive structural adhesive (8) is sprayed on the top of the battery pack (7), and a fixing plate (9) is connected thereto. A battery pack cover (11) connected to the lower housing (1) of the battery pack is provided on the top of the fixing plate (9). A wind-cooled heat exchange device (5) is connected above the top cover (11) of the battery pack. The side plate of the lower housing (1) of the battery pack is hollow inside, and the top of the side plate of the lower housing (1) of the battery pack is connected to the wind-cooled heat exchange device (5). A bottom air intake device (4) is provided at the bottom of the side plate of the lower housing (1) of the battery pack.

2. The liquid-cooled battery pack structure with forced air cooling heat exchange according to claim 1, characterized in that, The air-cooled heat exchange device (5) includes a base plate (5.1) and a cover plate (5.4). The cover plate (5.4) is connected above the base plate (5.1). The base plate (5.1) has ventilation openings on both sides that communicate with the side plates of the lower housing (1) of the battery pack. The cover plate (5.4) is provided with an exhaust port (5.5). A cooling fan (5.3) is installed on the exhaust port (5.5). An arc-shaped rib (5.2) is connected around the cooling fan (5.3) on the base plate (5.1). The top of the arc-shaped rib (5.2) is separated from the cover plate (5.4).

3. The liquid-cooled battery pack structure with forced air cooling heat exchange according to claim 1 or 2, characterized in that, The side plate of the lower housing (1) of the battery pack has a rectangular cross-section and is connected with several heat exchange fins (12) arranged in an interlaced manner, which divide the rectangular cross-section into several triangular cross-sections.

4. The liquid-cooled battery pack structure with forced air cooling heat exchange according to claim 1 or 2, characterized in that, The bottom air intake device (4) includes a trough (4.2), the top opening of the trough (4.2) is connected to the side plate of the lower housing (1) of the battery pack, a motor (4.1) is connected to the outer end face of the trough (4.2), the outer side plate of the trough (4.2) is a dustproof and breathable plate (4.6), and a baffle (4.5) parallel to the dustproof and breathable plate (4.6) is slidably connected inside the trough (4.2), and the baffle (4.5) is driven by the motor (4.1).

5. The liquid-cooled battery pack structure with forced air cooling heat exchange according to claim 1 or 2, characterized in that, Thermally conductive silicone pads (10) are connected to the upper and lower surfaces of the battery pack cover (11).

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