Thermal management system for air-liquid crossflow cooling of lithium battery packs

Abstract

The present application relates to a kind of air-liquid cross-flow cooling heat management systems for lithium battery pack, the air inlet and air outlet are arranged on the both sides of the battery compartment of lithium battery pack, the air inlet air is cooled battery after around-flow in battery compartment, and it is exported from air outlet;Several microchannel tube bundles connected with cooling water circulation are vertically arranged between each battery pack in battery compartment, microchannel tube bundle is along the air flow direction of air inlet to air outlet, and it is distributed in the range of angle of air flow injection, and air cross-flow heat exchange with cooling water in battery compartment, to maintain the constant of lithium battery operating temperature.Air and liquid cross-flow cooling mode is used, and microchannel tube bundle arranged between battery pack cools the air heated by battery pack, and according to the distribution of microchannel tube bundle in battery compartment, the temperature of air in battery compartment tends to be uniform.The problem that battery temperature is not uniform is overcome, and the maximum temperature difference in battery pack is maintained in relatively safe interval.

Description

Technical Field

[0001] This invention relates to a new energy vehicle battery technology, and more particularly to a thermal management system for air-liquid crossflow cooling of lithium battery packs. Background Technology

[0002] The power battery is a key component of electric vehicles, both a symbol and a constraint on their development. To improve battery performance and extend cycle life, the optimal maximum operating temperature for lithium batteries is 45℃, and the maximum temperature difference between individual cells should not exceed 5℃. Therefore, an efficient battery thermal management system (BTMS) is crucial for electric vehicles, determining the overall vehicle performance, safety, battery life, and manufacturing cost. Currently, air cooling is a common method for battery thermal management. Its principle is that air carries away heat by flowing over the battery surface through natural or forced convection. It features simple structure, easy manufacturing, and low cost. However, due to the low specific heat capacity of air, the temperature difference between the air inlet and outlet is large, resulting in a large temperature difference between battery cells, making it difficult to control below 5℃. This reduces battery charging and discharging efficiency and, in severe cases, can lead to thermal runaway, affecting the safety and lifespan of the entire system. Summary of the Invention

[0003] To address the issue of improving the performance of battery thermal management systems, an air-liquid crossflow cooling thermal management system for lithium battery packs is proposed. This system combines the advantages of air cooling and liquid cooling, effectively maintaining the uniformity of battery pack temperature, regulating the overall temperature level of the battery pack, and keeping the temperature inside the battery compartment at a healthy level.

[0004] The technical solution of the present invention is as follows: a thermal management system for air-liquid crossflow cooling of lithium battery packs, wherein air inlets and air outlets are provided on both sides of the battery compartment where the lithium battery packs are placed. The air entering through the air inlets flows around the battery compartment to cool the batteries and then exits through the air outlets. Several microchannel tube bundles connected to the cooling water circulation are vertically arranged between the battery packs in the battery compartment. The number of microchannel tube bundles gradually increases along the airflow direction from the air inlet to the air outlet and is distributed in a stepped manner in the direction of the airflow jet angle. The cooling water and air in the battery compartment exchange heat through crossflow to maintain a constant operating temperature of the lithium battery.

[0005] Preferably, the battery compartment is a thin-walled, open-top cube with an air inlet on one side and an air outlet on the opposite side. After the top cover is closed on the cube, the top surface of the cube has a microchannel cooling medium inlet, and the bottom surface has a microchannel cooling medium outlet. The two ends of the microchannel tube bundle pass through and are connected to the microchannel cooling medium inlet and the microchannel cooling medium outlet, respectively.

[0006] Preferably, the bottom of the battery compartment is fixedly connected to the battery sleeve by welding, and the battery sleeves are arranged in an array, with each battery sleeve accommodating one single battery cell.

[0007] Preferably, a temperature sensor is installed on the surface of the battery sleeve to monitor the battery temperature level and temperature uniformity.

[0008] Preferably, the battery sleeve is made of aluminum foil with a thickness of 1mm to prevent the battery from directly contacting air or moisture and causing corrosion, while maintaining heat conduction.

[0009] Preferably, the microchannel bundle has a diameter of 1.5 mm and is made of copper tubing.

[0010] Preferably, the air inlet and air outlet are equipped with speed sensors to adjust the air speed according to the battery temperature.

[0011] An application of an air-liquid crossflow cooling thermal management system for lithium battery packs: When installing the air-liquid crossflow cooling thermal management system for lithium battery packs, the microchannel tube bundle arrangement density in the battery compartment is selected according to the usage scenario; during battery pack operation, the air cooling and liquid cooling systems are turned on simultaneously, and the air intake volume and cooling water flow rate are adjusted by the temperature sensor on the battery surface. The overall temperature of the battery pack is controlled by the air intake volume, and the temperature uniformity inside the battery pack is controlled by the cooling water flow rate.

[0012] The beneficial effects of this invention are as follows: The air-liquid crossflow cooling thermal management system for lithium battery packs employs an air-liquid crossflow cooling method. Microchannel bundles arranged between the battery packs cool the air heated by the battery packs, and the distribution of the microchannel bundles within the battery compartment ensures a more uniform temperature distribution. Compared to traditional air-cooled battery pack thermal management systems, this invention overcomes the problem of uneven battery temperature by regulating the overall temperature level of the battery pack, maintaining the maximum temperature difference within the battery pack within a relatively safe range. This achieves the goals of improved performance, extended lifespan, and enhanced safety, which is of great significance for the development of efficient and stable battery thermal management systems. Attached Figure Description

[0013] Figure 1 This is an exploded view of the thermal management system for air-liquid crossflow cooling of lithium battery packs according to the present invention.

[0014] Figure 2 This is a schematic cross-sectional view of the thermal management system for air-liquid crossflow cooling of lithium battery packs according to the present invention;

[0015] Figure 3This is a schematic diagram of the low-density arrangement of microchannels in the thermal management system for air-liquid crossflow cooling of lithium battery packs according to the present invention.

[0016] Figure 4 This is a schematic diagram of the high-density arrangement of microchannels in the thermal management system for air-liquid crossflow cooling of lithium battery packs according to the present invention. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0018] like Figure 1 The exploded view shown is of an air-liquid crossflow cooling thermal management system for lithium battery packs. The main structures include battery compartment 1, upper cover plate 2, air inlet 3, air outlet 4, microchannel bundle 5, individual cells 6, and battery sleeve 7.

[0019] The battery compartment 1 is a thin-walled, open-top cube with an air inlet 3 on one side and an air outlet 4 on the opposite side. After the top cover 2 closes the cube, the top surface of the cube has a microchannel cooling medium inlet, and the bottom surface has a microchannel cooling medium outlet. The two ends of the microchannel tube bundle 5 pass through and connect to the microchannel cooling medium inlet and the microchannel cooling medium outlet, respectively. Several microchannel tube bundles 5 are arranged vertically between the various battery packs 6 in the battery compartment.

[0020] The battery sleeve 7 is fixedly connected to the bottom of the battery compartment 1 by welding. The arrangement of the battery sleeves 7 is as follows: Figure 3 It is a rectangular array of four rows and five columns. Each battery sleeve 7 can hold one single cell battery 6, for a total of twenty single lithium-ion cells.

[0021] Reference Figure 2 The battery compartment 1 is placed horizontally, and the microchannel bundle 5 is arranged vertically within it. The microchannel bundle 5 enters the battery compartment 1 through the top cover 2 and exits from the bottom. The distribution of the microchannel bundle 5 is determined based on the temperature distribution of the air and the battery within the air-cooled battery compartment 1. Specifically, it is distributed in a stepped manner along the airflow direction (from the air inlet 3 to the air outlet 4) and towards the airflow injection angle. To adapt to different scenario requirements, this invention provides both high-density and low-density solutions. The specific arrangement is described in [reference needed]. Figure 3 , 4 .

[0022] During operation, such as Figure 2As shown, cooling water flows from top to bottom through the inlet of the upper microchannel bundle 5 and to the outlet of the lower microchannel bundle 5. Air enters the battery compartment 1 through the air inlet 3 and exits through the air outlet 4. The air flows in the main channel, circulating around and cooling the battery. Then, the cooling water in the microchannel bundle 5 cross-flows with the air for heat exchange, carrying away the heat accumulated in the air to maintain the temperature uniformity within the battery compartment 1. As the air flows through the battery compartment 1, the temperature at the air inlet is lower than that at the air outlet, causing the air's heat exchange capacity to gradually weaken. Therefore, the number of microchannels gradually increases along the airflow direction, arranged in a stepped manner. The arrangement density is set according to the heat load requirements. This invention provides two arrangement schemes, high density and low density, to adapt to different heat load requirements. The arrangement method is shown in the attached figure. Figure 4 and Figure 3 .

[0023] A temperature sensor is installed on the surface of the battery sleeve 7 to monitor the battery temperature level and temperature uniformity.

[0024] The air inlet 3 and air outlet 4 can be equipped with speed sensors to adjust the air speed according to the battery temperature.

[0025] The battery sleeve 7 is made of aluminum foil with a thickness of 1mm to prevent the battery from directly contacting air or moisture and causing corrosion, while maintaining good heat conduction.

[0026] The microchannel bundle 5 has a diameter of 1.5 mm and is made of copper tubing.

[0027] During system installation, high- or low-density microchannel tube bundle schemes are selected based on the usage scenario. During battery pack operation, both air cooling and liquid cooling systems are activated simultaneously, with airflow and cooling water flow rate adjusted via temperature sensors on the battery surface. Typically, the overall battery pack temperature is controlled by the airflow, while the internal temperature uniformity is controlled by the cooling water flow rate. These parameters can be adjusted in real-time based on data collected by the temperature sensors. A healthy temperature range is maintained where the overall battery pack temperature does not exceed 318.5K, and the maximum internal temperature difference does not exceed 5K.

[0028] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An air-liquid cross flow cooled thermal management system for a lithium battery pack, characterized by, A plurality of micro-channel tube bundles connected with cooling water circulation are arranged vertically between each battery pack in the battery compartment, and the number of micro-channel tube bundles gradually increases along the airflow direction from the air inlet to the air outlet, and the micro-channel tube bundles are distributed in a stepped manner along the air injection angle direction; The battery compartment is a thin-walled lidless cube, one side of which is provided with an air inlet, and the opposite side is provided with an air outlet. After the upper cover plate covers the cube, the top surface of the cube is left with a micro-channel cooling medium inlet, and the bottom surface is a micro-channel cooling medium outlet. The two ends of the micro-channel tube bundle pass through and connect the micro-channel cooling medium inlet and the micro-channel cooling medium outlet, respectively; The diameter of the micro-channel tube bundle is 1.5 mm, and the copper pipe material is used; The bottom of the battery compartment is fixedly connected with the battery sleeve by welding, and the battery sleeve is arranged in an array. Each battery sleeve contains a single battery; A temperature sensor is installed on the surface of the battery sleeve to monitor the battery temperature level and temperature uniformity; During operation, cooling water flows from the top to the bottom through the micro-channel tube bundle inlet at the top and the micro-channel tube bundle outlet at the bottom; Air enters the battery compartment through the air inlet and leaves the battery compartment through the air outlet; Air flows in the main flow channel, flows around the battery, and then the cooling water in the micro-channel tube bundle cross-flow exchanges heat with the air to take away the heat accumulated in the air to maintain the uniformity of the temperature in the battery compartment.

2. The air-liquid cross flow cooling thermal management system for lithium battery packs of claim 1, wherein, The battery sleeve is made of aluminum foil with a thickness of 1 mm to avoid direct contact between the battery and air or moisture, which can cause corrosion, while maintaining the heat conduction effect.

3. The air-liquid cross flow cooling thermal management system for lithium battery packs of claim 1 or 2, characterized in that, Speed sensors are arranged at the air inlet and the air outlet to adjust the air speed according to the battery temperature condition.

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