System, device and method for testing heat dissipation performance of power battery

Abstract

The invention discloses a system, a device and a method for testing the heat dissipation performance of a power battery, relates to the technical field of battery heat dissipation, and is technically characterized by comprising a temperature and humidity control module, a monitoring module, a refrigerant circulation module and a battery cooling liquid circulation module. The test system for integrating the air conditioning loop with the battery cooling loop is developed, the heating simulator and the resistance simulator are used for replacing the battery pack, the power of the heating simulator is changed to simulate the heating value of the battery pack under different working conditions, and the rotating speed of the compressor, the rotating speed of the water pump and the wind speed rotating speed are adjusted to test the heat dissipation performance of the battery under different environment temperatures. The method has the characteristics of simple system, high test efficiency and strong replaceability.

Description

Technical Field

[0001] The present invention relates to the technical field of battery heat dissipation, and in particular to a system, device and method for testing the heat dissipation performance of a power battery. Background Art

[0002] In order to reduce dependence on fossil energy and reduce automobile pollutant emissions, the development focus of the automobile industry has shifted to new energy vehicles. New energy vehicles use batteries to provide energy for the entire vehicle. Usually, in order to increase the range of new energy vehicles, higher-power power batteries are used. Since the operating temperature of the battery will have a serious impact on the range of commercial vehicles, the requirements for the thermal management performance of the battery have also become higher, so it is necessary to test the heat dissipation performance of the battery.

[0003] At present, when testing the heat dissipation performance of power batteries, the battery pack needs to be placed on a test bench as a whole. This method has certain disadvantages: 1. Due to the large size of the battery pack, it is not convenient to move and fix when there are a large number of battery packs. 2. The battery pack needs to be equipped with a battery charging and discharging system, which is relatively expensive. 3. The operating voltage of the battery pack is relatively high, and there are certain safety hazards during bench testing. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and to provide a system, device and method for testing the heat dissipation performance of a power battery.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] The present invention provides a testing system for the heat dissipation performance of a power battery, comprising the following modules:

[0007] Temperature and humidity control module: including constant temperature and humidity chamber;

[0008] Monitoring module: including a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor, a first pressure sensor, a second pressure sensor, a third pressure sensor, a fourth pressure sensor, a first flow meter, a second flow meter and an anemometer;

[0009] Refrigerant cycle module: including compressor, condensing mechanism, electronic expansion valve and gas-liquid separator;

[0010] Battery coolant circulation module: includes refrigeration device, water pump, expansion water tank and testing device.

[0011] The present invention is further configured as follows: the monitoring module and the heat dissipation module are placed inside a constant temperature and humidity chamber; the gas-liquid separator absorbs liquid in the refrigerant to prevent the liquid from entering the compressor; the output end of the gas-liquid separator is connected to the input end of the compressor; the compressor compresses the low-temperature and low-pressure gaseous refrigerant into a high-temperature and high-pressure gaseous refrigerant; the output end of the compressor is provided with a first temperature sensor and a first pressure sensor; the output end of the compressor is connected to the input end of a condensing mechanism; the condensing mechanism includes a condenser and a fan; the condenser condenses the high-temperature and high-pressure gaseous refrigerant into a medium-temperature and high-pressure liquid refrigerant; the fan is fixed on the outside of the condenser; the condensing mechanism is provided with a fifth temperature sensor and an anemometer; the output end of the condensing mechanism is provided with a second temperature sensor, a second pressure sensor and a first flow meter; the output end of the condensing mechanism is connected to the input end of the electronic expansion valve; The electronic expansion valve changes the pressure of the refrigerant to ensure the purity of the liquid refrigerant entering the chiller refrigeration device. The output end of the electronic expansion valve is connected to the input end of the refrigeration device. The refrigeration device enables heat exchange between the refrigerant and the coolant of the test device. The output end of the refrigeration device is connected to a water pump. A second flow meter is provided on the output end of the water pump. The output end of the water pump is connected to an expansion water tank. The expansion water tank replenishes the coolant in the cooling circuit of the test device. A fourth temperature sensor and a fourth pressure sensor are provided on the output end of the expansion water tank. The output end of the expansion water tank is connected to the test device. The test device includes a heating simulator, a resistance simulator and a DC power supply. The resistance simulator includes a flow regulating valve and a pressure gauge. A third temperature sensor and a third pressure sensor are provided on the output end of the test device. The output end of the test device is connected to the refrigeration device.

[0012] The present invention is further configured as follows: the first temperature sensor and the second temperature sensor measure the refrigerant temperature for calculating the superheat of the refrigerant, the third temperature sensor and the fourth temperature sensor measure the coolant temperature for calculating the battery cooling capacity, and the fifth temperature sensor measures the air side temperature of the condenser.

[0013] The present invention is further configured as follows: the first pressure sensor and the second pressure sensor measure the refrigerant pressure for calculating the superheat of the refrigerant, and the third pressure sensor and the fourth pressure sensor measure the coolant pressure for calculating the pressure drop of the resistance simulator.

[0014] The present invention is further configured as follows: the first flow meter measures the flow rate of the refrigerant circuit, and the second flow meter measures the flow rate of the coolant circuit.

[0015] The present invention is further configured as follows: the anemometer measures the air side flow velocity of the condenser, which matches the rotation speed of the compressor.

[0016] The present invention also provides a testing device for the heat dissipation performance of a power battery: the DC power supply is connected to a heating simulator, the main body of the heating simulator is an aluminum alloy cylindrical container, including a top plate, a bottom plate and a thin-walled tube, the top plate, the bottom plate and the thin-walled tube are welded together, there are four openings on the top plate, heating tubes are inserted into three of the openings, the heating tubes have an external thread of DN40, and are fixedly installed by a matching wire seat, the matching wire seat is welded to the top plate, the other opening is a water injection port, and an aluminum alloy coil is welded and wrapped around the outer wall of the thin-walled tube; the resistance simulator includes a flow regulating valve and a pressure gauge, the flow regulating valve is electrically adjusted, the pressure adjustment range of the resistance simulator is 0 to 0.25 MPa, the left and right sides of the resistance simulator are DN20 internal threads, and the resistance simulator is connected to the external thread of a nylon bellows joint through an adapter.

[0017] The present invention is further configured as follows: the model of the heating tube is determined according to the heating power requirement, the power of a single heating tube is selected to be 9kW, the diameter is 47mm, the length is 450mm, the single heating tube is composed of three heating wires in parallel, the total thermal resistance of the heating tube is 5.3Ω, and when the voltage is 220V, the total current of the single heating tube is 42A; in order to achieve a higher heating power, three 9kW heating tubes are selected in series, when the current of a single heating tube reaches a maximum of 42A, the total power is 28kW, and the total voltage is 667V; in actual use, the heating tube is connected to a DC power supply, the voltage of the heating tube can be remotely adjusted to achieve the adjustment of the heating power, and the corresponding heating power is set according to the working state of the test device.

[0018] The present invention also provides a method for testing the heat dissipation performance of a power battery, comprising the following steps:

[0019] Step S1: adjusting the ambient temperature of the test system through a constant temperature and humidity chamber;

[0020] Step S2: setting the power of the heating simulator according to the heat generated by the battery under different working conditions;

[0021] Step S3: Selecting a test method for maintaining a maximum coolant circuit flow rate or a maximum cooling capacity according to the test situation;

[0022] Step S4: measuring the temperature of the coolant before and after the test device, and the flow rate of the coolant circuit of the test device;

[0023] Step S5: Analyze the heat dissipation performance of the battery to obtain the relationship between the battery temperature and time, and the optimal cooling capacity required under different working conditions.

[0024] The present invention is further configured as follows: in the step S3, when it is necessary to test the influence of different cooling capacities on the heat dissipation performance of the battery, the water pump speed is adjusted to the maximum, the cooling liquid pressure drop before and after the test device is controlled by the flow regulating valve, the fan speed is adjusted to control the air flow rate passing through the condenser surface, and the fan speed is proportional to the compressor speed; when it is necessary to test the influence of the coolant flow rate on the heat dissipation performance of the battery, the maximum fan speed and the maximum compressor speed are adjusted to maintain the maximum cooling capacity, the water pump speed is adjusted from small to large, and the cooling liquid pressure drop before and after the test device is controlled by the flow regulating valve.

[0025] Compared with the prior art, this solution has the following beneficial effects:

[0026] The present invention develops a test system that integrates a battery cooling circuit with an air-conditioning circuit, utilizes a heating simulator and a resistance simulator to replace a battery pack, changes the power of the heating simulator to simulate the heat generation of the battery pack under different working conditions (charging, discharging, driving, etc.), and adjusts the compressor speed, water pump speed, and wind speed to test the battery heat dissipation performance under different ambient temperatures. The system has the characteristics of simple system, high test efficiency, and strong substitutability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A heat dissipation performance testing system according to an embodiment of the present invention;

[0028] Figure 2 is a heating and resistance simulator in an embodiment of the present invention;

[0029] Figure 3 This is the working principle of the heating simulator and the resistance simulator in the embodiment of the present invention;

[0030] Figure 4 It is a flow chart of battery thermal management performance testing in an embodiment of the present invention.

[0031] In the figure: 1. Constant temperature and humidity chamber; 2. Compressor; 3. Condenser; 4. Fan; 5. Electronic expansion valve; 6. Refrigeration device; 7. Gas-liquid separator; 8. Water pump; 9. Expansion water tank; 10. Heating tube; 11. Water inlet; 12. Coil; 13. Water tank; 14. Heating simulator; 15. DC power supply; 16. Flow control valve; 17. Pressure gauge; T1, first temperature sensor; T2, second temperature sensor; T3, third temperature sensor; T4, fourth temperature sensor; T5, fifth temperature sensor; Q1, first flow meter; Q2, second flow meter; P1, first pressure sensor; P2, second pressure sensor; P3, third pressure sensor; P4, fourth pressure sensor; V1, anemometer; L1 is the refrigerant circulation loop; L2 is the coolant circulation loop. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution of the present invention will be further described in detail below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0034] Example:

[0035] Power battery heat dissipation performance test system, such as Figure 1 As shown, based on the air conditioning cooling loop, a test system for the heat dissipation performance of the battery pack is constructed. The refrigerant in the air conditioning loop and the coolant in the battery pack loop exchange heat in the chiller refrigeration device. The entire test system is placed in a constant temperature and humidity chamber, and different environmental conditions are simulated by controlling the temperature of the constant temperature and humidity chamber. The test system connects the test system loop through pipes and valves, and simulates the heat generation and cooling method of the battery pack through a heating simulator and a resistance simulator. The water pump and fan are used to adjust the coolant and air flow to test the battery heat dissipation performance under different conditions.

[0036] The main technical solutions are as follows:

[0037] 1. Control the temperature and humidity of the external environment of the test system through a constant temperature and humidity chamber;

[0038] 2. Control the air volume of the condenser by a fan, measure the air temperature of the condenser by a fifth temperature sensor, and measure the air flow rate through the condenser by an anemometer;

[0039] 3. Measure the refrigerant pressure flowing through the condenser by means of the first pressure sensor and the second pressure sensor, measure the refrigerant temperature flowing through the condenser by means of the first temperature sensor and the second temperature sensor, and measure the refrigerant flow by means of the first flow meter;

[0040] 4. Measure the pressure of the coolant flowing through the test device through the third pressure sensor and the fourth pressure sensor, measure the temperature of the coolant flowing through the test device through the third temperature sensor and the fourth temperature sensor, and measure the coolant flow rate of the test device circuit through the second flow meter;

[0041] 5. Heat exchange between the test device circuit and the refrigerant circuit is achieved through the chiller refrigeration device.

[0042] The key components are shown in Table 1:

[0043] Table 1 Description of key components

[0044] Key components Key Parameters Functional Description Constant temperature and humidity chamber Adjust the temperature to 15~60℃ Regulate the temperature and humidity outside the test system compressor With 540V power supply Compress low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gaseous refrigerant Condenser Test Unit Condensing high temperature and high pressure gaseous refrigerant into medium temperature and high pressure liquid refrigerant fan With 540V power supply The refrigerant is cooled by forcing air to flow across the condenser surface. Electronic expansion valve Maximum flow rate 60L / min Change the refrigerant pressure to ensure the purity of the liquid refrigerant entering the chiller chiller refrigeration device Maximum heat exchange capacity 30kW Heat exchange between refrigerant and test device coolant Gas-liquid separator Applicable R124a refrigerant Absorbs liquid in refrigerant to prevent liquid from entering the compressor Water Pump Maximum flow rate 35L / min Realize the circulation of coolant in test equipment Expansion tank Volume greater than 3L Refilling the coolant in the test rig cooling circuit <![CDATA[Temperature sensors (T1, T2)]]> Range: -40~200℃ Measures refrigerant temperature and is used to calculate the refrigerant superheat <![CDATA[Pressure sensors (P1, P2)]]> Range 0~2.5MPa Measuring refrigerant pressure to calculate refrigerant superheat <![CDATA[Flowmeter Q1]]> Range 0~60L / min Measuring flow rates in refrigerant circuits <![CDATA[Temperature sensors (T3, T4)]]> Range: -40~200℃ Measure coolant temperature to calculate battery cooling capacity <![CDATA[Pressure sensors (P3, P4)]]> Range 0~0.25MPa Measures coolant pressure for calculating drag simulator pressure drop <![CDATA[Flowmeter Q2]]> Range 0~35L / min Measuring flow in coolant circuits <![CDATA[Temperature sensor T5]]> Range: -20~60℃ Measuring the air side temperature of the condenser <![CDATA[Wind speed meter V1]]> Wind speed 0~25m / s Measure the air side flow rate of the condenser and match it with the compressor speed

[0045] 2. Test equipment

[0046] The battery pack is simulated by the test device, and the heat generation of the battery is achieved by the heating simulator, such as Figure 2 As shown, the main body of the heating simulator is an aluminum alloy cylindrical container with a diameter of 270 mm and a height of 510 mm. The wall thickness of the cylindrical tube is 1.5 mm, the thickness of the upper and lower plates is 2.5 mm, the upper and lower bottom plates are welded together with the thin-walled tube, and there are four openings on the top plate, three of which are used to insert heating tubes, and the other opening is a water injection port. The outer wall of the aluminum alloy container is wrapped with an aluminum alloy coil and fixed to the outer wall by welding. After installation, a certain amount of water is added to the container through the water injection port. The heating tube has a DN40 external thread and is fixedly installed by a matching wire seat. The matching wire seat is welded to the top plate. The heating tube transfers heat to the coolant of the coil through water at a given power.

[0047] The model of the heating tube is determined according to the heating power requirement. The power of a single heating tube is selected to be 9kW, the diameter of the heating tube is 47mm, and the length is 450mm. A single heating tube is composed of three heating wires in parallel. The total thermal resistance of the heating tube is 5.3Ω. When the voltage is 220V, the total current of a single heating tube is 42A. In order to achieve greater heating power, three 9kW heating tubes are selected in series. When the current of a single heating tube reaches the maximum of 42A, the total power is 28kW and the total voltage is 667V. In actual use, the heating tube is connected to a DC power supply. The voltage of the heating tube can be remotely adjusted to adjust the heating power. The corresponding heating power is set according to the working status of the battery pack (charging, discharging, driving, etc.).

[0048] In addition to simulating the battery pack heating, it is also necessary to simulate the resistance of the battery pack. Install a resistance simulator behind the heating simulator, such as Figure 3 As shown, the resistance simulator uses an electric regulating valve to adjust the resistance of the fluid by controlling the opening of the valve. The pressure adjustment range of the resistance simulator is 0-0.25MPa. The left and right sides of the resistance simulator are DN20 internal threads, which are connected to the external threads of the nylon bellows connector through an adapter.

[0049] 3. Test Method

[0050] During the test, the test device heating and resistance simulator simulates the heat generation of the battery pack and the heat exchange flow resistance of the water cooling plate. The cooperation of the water pump, flow control valve, heating tube and power supply can realize the heat generation and coolant circulation process of the test device. The coolant and the refrigerant of the air conditioning system exchange heat in the chiller refrigeration device to achieve the cooling of the test device. The temperature, pressure and flow data of the coolant circuit of the test device are recorded through the temperature sensor, pressure sensor and flow meter of the coolant circuit, and the measurement data is analyzed and processed, so as to realize the analysis of the heat dissipation efficiency and reliability of the battery pack.

[0051] Battery thermal management performance test process Figure 4 As shown, in order to simulate the high temperature working environment in summer, the temperature of the constant temperature and humidity chamber is set to 35°C, so that the condenser inlet air temperature and the battery temperature are maintained at 35°C. The heating simulator is used to give the corresponding power to the heat generated by the battery in different working states (discharging, charging, driving, etc.). The test process is divided into two categories. The first category is to maintain the maximum flow rate of the coolant circuit, change the cooling capacity of the refrigerant circuit, and test the impact of different cooling capacities on the heat dissipation performance of the battery; the second category is to maintain the maximum cooling capacity, change the flow rate of the coolant circuit, and test the impact of the coolant flow rate on the heat dissipation performance of the battery. During the test, the temperature before and after the coolant flows through the test device, as well as the flow rate of the coolant circuit of the test device, are recorded to analyze the heat dissipation performance of the power battery. The relationship between the change of battery temperature over time and the minimum cooling capacity required under different working conditions can be obtained.

[0052] The above specific embodiments are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make modifications to the embodiments without any creative contribution as needed. However, such modifications are protected by the patent law as long as they are within the scope of the claims of the present invention.

Claims

1. The test system for heat dissipation performance of power batteries is characterized by: Includes the following modules: Temperature and humidity control module: including constant temperature and humidity chamber; Monitoring module: including a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor, a first pressure sensor, a second pressure sensor, a third pressure sensor, a fourth pressure sensor, a first flow meter, a second flow meter and an anemometer; Refrigerant cycle module: including compressor, condensing mechanism, electronic expansion valve and gas-liquid separator; Battery coolant circulation module: includes refrigeration device, water pump, expansion water tank and testing device.

2. The power battery heat dissipation performance testing system according to claim 1, characterized in that: The monitoring module and the heat dissipation module are placed inside the constant temperature and humidity chamber; the gas-liquid separator absorbs the liquid in the refrigerant to prevent the liquid from entering the compressor, the output end of the gas-liquid separator is connected to the input end of the compressor, the compressor compresses the low-temperature and low-pressure gaseous refrigerant into a high-temperature and high-pressure gaseous refrigerant, the output end of the compressor is provided with a first temperature sensor and a first pressure sensor, the output end of the compressor is connected to the input end of the condensing mechanism, the condensing mechanism includes a condenser and a fan, the condenser condenses the high-temperature and high-pressure gaseous refrigerant into a medium-temperature and high-pressure liquid refrigerant, the fan is fixed on the outside of the condenser, the condensing mechanism is provided with a fifth temperature sensor and an anemometer, the output end of the condensing mechanism is provided with a second temperature sensor, a second pressure sensor and a first flow meter, the output end of the condensing mechanism is connected to the input end of the electronic expansion valve, the electronic expansion valve The valve changes the pressure of the refrigerant to ensure the purity of the liquid refrigerant entering the chiller refrigeration device. The output end of the electronic expansion valve is connected to the input end of the refrigeration device. The refrigeration device enables heat exchange between the refrigerant and the coolant of the test device. The output end of the refrigeration device is connected to a water pump. A second flow meter is provided on the output end of the water pump. The output end of the water pump is connected to an expansion water tank. The expansion water tank replenishes the coolant in the cooling circuit of the test device. A fourth temperature sensor and a fourth pressure sensor are provided on the output end of the expansion water tank. The output end of the expansion water tank is connected to the test device. The test device includes a heating simulator, a resistance simulator and a DC power supply. The resistance simulator includes a flow regulating valve and a pressure gauge. A third temperature sensor and a third pressure sensor are provided on the output end of the test device. The output end of the test device is connected to the refrigeration device.

3. The power battery heat dissipation performance testing system according to claim 2, characterized in that: The first temperature sensor and the second temperature sensor measure the refrigerant temperature for calculating the superheat of the refrigerant, the third temperature sensor and the fourth temperature sensor measure the coolant temperature for calculating the battery cooling capacity, and the fifth temperature sensor measures the air side temperature of the condenser.

4. The power battery heat dissipation performance testing system according to claim 2, characterized in that: The first pressure sensor and the second pressure sensor measure the refrigerant pressure for calculating the superheat of the refrigerant, and the third pressure sensor and the fourth pressure sensor measure the coolant pressure for calculating the pressure drop of the resistance simulator.

5. The power battery heat dissipation performance testing system according to claim 2, characterized in that: The first flow meter measures the flow rate of the refrigerant circuit, and the second flow meter measures the flow rate of the coolant circuit.

6. The power battery heat dissipation performance testing system according to claim 2, characterized in that: The anemometer measures the air side flow rate of the condenser, which matches the compressor speed.

7. A test device for heat dissipation performance of a power battery, characterized by: The DC power supply is connected to the heating simulator. The main body of the heating simulator is an aluminum alloy cylindrical container, including a top plate, a bottom plate and a thin-walled tube, which are welded together. There are four openings on the top plate, three of which are used to insert heating tubes. The heating tubes have DN40 external threads and are fixedly installed by matching wire seats, which are welded to the top plate. The other opening is a water injection port, and an aluminum alloy coil is welded and wrapped around the outer wall of the thin-walled tube. The resistance simulator includes a flow regulating valve and a pressure gauge. The flow regulating valve is electrically adjusted. The pressure adjustment range of the resistance simulator is 0 to 0.25 MPa. The left and right sides of the resistance simulator are DN20 internal threads. The resistance simulator is connected to the external thread of a nylon bellows joint through an adapter.

8. The device for testing the heat dissipation performance of a power battery according to claim 7, characterized in that: The model of the heating tube is determined according to the heating power requirement. The power of a single heating tube is selected to be 9kW, the diameter is 47mm, and the length is 450mm. A single heating tube is composed of three heating wires in parallel. The total thermal resistance of the heating tube is 5.3Ω. When the voltage is 220V, the total current of the single heating tube is 42A. In order to achieve a higher heating power, three 9kW heating tubes are selected in series. When the current of a single heating tube reaches a maximum of 42A, the total power is 28kW and the total voltage is 667V. In actual use, the heating tube is connected to a DC power supply, and the voltage of the heating tube can be remotely adjusted to adjust the heating power. The corresponding heating power is set according to the working status of the test device.

9. The test method for heat dissipation performance of power batteries is characterized by: The following steps are involved: Step S1: adjusting the ambient temperature of the test system through a constant temperature and humidity chamber; Step S2: setting the power of the heating simulator according to the heat generated by the battery under different working conditions; Step S3: Selecting a test method for maintaining a maximum coolant circuit flow rate or a maximum cooling capacity according to the test situation; Step S4: measuring the temperature of the coolant before and after the test device, and the flow rate of the coolant circuit of the test device; Step S5: Analyze the heat dissipation performance of the battery to obtain the relationship between the battery temperature and time, and the optimal cooling capacity required under different working conditions.

10. The method for testing the heat dissipation performance of a power battery according to claim 9, characterized in that: In step S3, when it is necessary to test the influence of different cooling capacities on the heat dissipation performance of the battery, the water pump speed is adjusted to the maximum, the cooling liquid pressure drop before and after the test device is controlled by the flow regulating valve, the fan speed is adjusted to control the air flow rate passing through the condenser surface, and the fan speed is proportional to the compressor speed; when it is necessary to test the influence of the coolant flow rate on the heat dissipation performance of the battery, the maximum fan speed and the maximum compressor speed are adjusted to maintain the maximum cooling capacity, the water pump speed is adjusted from small to large, and the cooling liquid pressure drop before and after the test device is controlled by the flow regulating valve.

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