Control method of thermal management system and thermal management system

Abstract

The embodiment of the invention discloses a control method of a thermal management system and the thermal management system. The thermal management system is used for refrigerating or heating a battery. The method comprises the steps that the temperature and pressure of the thermal management system are obtained; when a signal related to refrigerant recovery is detected, the opening degree of a throttling component, an electromagnetic valve and a compressor are controlled to be started, the rotating speed of the compressor is adjusted according to the temperature and the pressure, the working time of the compressor and the working time of the electromagnetic valve are controlled, and the refrigerant amount lost by the heat management system is determined; the heat management system works in a refrigerant recovery stage and completes refrigerant recovery work; and when a signal associated with refrigerant recharging is detected, the electromagnetic valve is controlled to be opened, and the working state of the electromagnetic valve is controlled according to the refrigerant inlet pressure and the refrigerant outlet pressure of the battery, so that the heat management system works in the refrigerant recharging stage and completes the refrigerant recharging work. According to the technical scheme provided by the embodiment of the invention, the refrigerant loss can be reduced, and the refrigerant recovery and reutilization efficiency can be improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to thermal management technology, and more particularly to a control method for a thermal management system and a thermal management system. Background Technology

[0002] Thermal management systems, as devices that cool or heat tested components such as batteries, regulate battery temperature through the transfer of refrigerant. Currently, existing thermal management system control methods typically require manual assistance during refrigerant recovery and recharging, resulting in significant refrigerant loss and low efficiency in refrigerant recovery and reuse. Summary of the Invention

[0003] This invention provides a control method and a thermal management system for reducing refrigerant loss and improving refrigerant recovery and reuse efficiency.

[0004] In a first aspect, embodiments of the present invention provide a control method for a thermal management system. The thermal management system is used to cool or heat a battery. The thermal management system includes: a compressor, a condenser, a gas-liquid separator, a throttling component, a solenoid valve, and a controller. The outlet of the compressor is sequentially connected to the condenser and the throttling component. The throttling component is connected to the refrigerant inlet of the battery via a first pipeline. The inlet of the compressor is connected to the gas-liquid separator. The gas-liquid separator is connected to the refrigerant outlet of the battery via a second pipeline. The solenoid valve is installed in both the first and second pipelines. The controller is electrically connected to the compressor, the solenoid valve, and the throttling component. The control method is executed by the controller. The control method includes:

[0005] The temperature and pressure of the thermal management system are obtained, wherein the temperature includes the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the pressure includes the inlet pressure and outlet pressure of the compressor, and the refrigerant inlet pressure and refrigerant outlet pressure of the battery;

[0006] When a signal associated with refrigerant recovery is detected, the opening degree of the throttling component, the opening of the solenoid valve, and the starting of the compressor are controlled. The speed of the compressor is adjusted according to the temperature and pressure, the working time of the compressor and the working time of the solenoid valve are controlled, and the amount of refrigerant lost by the thermal management system is determined so that the thermal management system operates in the refrigerant recovery stage and completes the refrigerant recovery work.

[0007] When a signal associated with refrigerant recharge is detected, the solenoid valve is opened, and the working state of the solenoid valve is controlled according to the refrigerant inlet pressure and refrigerant outlet pressure of the battery, so that the thermal management system operates in the refrigerant recharge stage and completes the refrigerant recharge work.

[0008] Optionally, adjusting the compressor speed, controlling the compressor's operating time, and the solenoid valve's operating time based on the temperature and pressure, and determining the refrigerant loss in the thermal management system, includes:

[0009] When the compressor operates for a preset first duration, the solenoid valve of the first pipeline is closed.

[0010] When the minimum value of the refrigerant inlet pressure and the refrigerant outlet pressure of the battery is greater than a preset first pressure threshold, the optimal refrigerant recovery time is calculated based on the compressor inlet pressure and the compressor outlet pressure; the preset first pressure threshold is the minimum allowable value of the compressor suction pressure.

[0011] When the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is less than or equal to the preset first pressure threshold, or when the working time of the compressor reaches the sum of the preset second time and the optimal refrigerant recovery time, the solenoid valve of the second pipeline is controlled to close, and when the closing time of the solenoid valve of the second pipeline reaches the preset third time, the compressor is controlled to stop working.

[0012] When the compressor stops working for a preset fourth time period, the amount of refrigerant lost by the thermal management system is calculated based on the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the refrigerant inlet pressure and refrigerant outlet pressure of the battery.

[0013] Optionally, after calculating the refrigerant loss of the thermal management system, the process includes:

[0014] The difference between the amount of refrigerant in the thermal management system before refrigerant recovery and the amount of refrigerant lost by the refrigerant system is used as the amount of refrigerant in the thermal management system after refrigerant recovery, so as to update the amount of refrigerant in the thermal management system.

[0015] Optionally, the amount of refrigerant lost by the thermal management system Among them, M ref Z represents the molar mass of the refrigerant. ref Where R is the compressibility factor of the refrigerant, R is the ideal gas constant, and M is the compressibility factor of the refrigerant. ref Z ref R and P are both known quantities. batt =Min(P1, P2), where P1 is the refrigerant inlet pressure of the battery, P2 is the refrigerant outlet pressure of the battery, and T at The ambient temperature of the battery is related to the average of the refrigerant inlet temperature and the refrigerant outlet temperature of the battery.

[0016] Optionally, adjusting the compressor speed includes:

[0017] When the ratio of the compressor's outlet pressure to its inlet pressure is greater than a preset first compression ratio, the compressor's speed is controlled to decrease.

[0018] When the ratio of the compressor's outlet pressure to its inlet pressure is less than a preset second compression ratio, the compressor's speed is controlled to increase, and the preset first compression ratio is greater than the preset second compression ratio.

[0019] Optionally, the preset first compression ratio is greater than the rated compression ratio of the compressor, and the preset second compression ratio is less than the rated compression ratio of the compressor.

[0020] Optionally, controlling the operating state of the solenoid valve based on the refrigerant inlet pressure and refrigerant outlet pressure of the battery includes:

[0021] When the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is within a preset range, the solenoid valve is controlled to close, so that the thermal management system can complete the refrigerant recharge operation.

[0022] Secondly, embodiments of the present invention provide a thermal management system, including: a compressor, a condensing device, a gas-liquid separator, a throttling component, a solenoid valve, and a controller. The outlet of the compressor is sequentially connected to the condensing device and the throttling component. The throttling component is connected to the refrigerant inlet of the battery via a first pipeline. The inlet of the compressor is connected to the gas-liquid separator. The gas-liquid separator is connected to the refrigerant outlet of the battery via a second pipeline. The solenoid valve is installed in both the first pipeline and the second pipeline. The controller is electrically connected to the compressor, the solenoid valve, and the throttling component. The control method described in the first aspect is executed by the controller.

[0023] Optionally, the solenoid valve includes a first solenoid valve and a second solenoid valve, wherein the first solenoid valve is located in the first pipeline and the second solenoid valve is located in the second pipeline.

[0024] Optionally, both the refrigerant inlet and the refrigerant outlet are equipped with pressure sensors and temperature sensors, and both the compressor outlet and inlet are equipped with pressure sensors. Each pressure sensor and each temperature sensor is electrically connected to the controller.

[0025] The present invention provides a control method and a thermal management system for a thermal management system. The thermal management system is used to cool or heat a battery. The thermal management system includes: a compressor, a condenser, a gas-liquid separator, a throttling device, a solenoid valve, and a controller. The compressor outlet is sequentially connected to the condenser and the throttling device. The throttling device is connected to the refrigerant inlet of the battery through a first pipeline. The compressor inlet is connected to the gas-liquid separator, and the gas-liquid separator is connected to the refrigerant outlet of the battery through a second pipeline. Solenoid valves are installed in both the first and second pipelines. The controller is electrically connected to the compressor, the solenoid valves, and the throttling device. The control method is executed by the controller. The control method includes: acquiring the temperature and pressure of the thermal management system, where the temperature includes the temperature at the battery's refrigerant inlet. Temperature and refrigerant outlet temperature, pressure including compressor inlet and outlet pressures, and battery refrigerant inlet and outlet pressures; when a signal associated with refrigerant recovery is detected, the opening degree of the throttling device, the solenoid valve opens, the compressor starts, and the compressor speed is adjusted according to temperature and pressure, the compressor operating time and the solenoid valve operating time are controlled, and the amount of refrigerant lost by the thermal management system is determined, so that the thermal management system operates in the refrigerant recovery stage and completes the refrigerant recovery work; when a signal associated with refrigerant recharge is detected, the solenoid valve is opened, and the operating state of the solenoid valve is controlled according to the battery refrigerant inlet and outlet pressures, so that the thermal management system operates in the refrigerant recharge stage and completes the refrigerant recharge work. The control method and thermal management system provided in this invention control the opening degree of the throttling component, the working state of the solenoid valve, and the working state of the compressor based on the acquired temperature and pressure and the detected signals. This enables the thermal management system to perform refrigerant recovery or recharge automatically without manual assistance. This solves the problems of high refrigerant loss and low refrigerant recovery and reuse efficiency in the prior art that require manual assistance, thereby reducing refrigerant loss and improving refrigerant recovery and reuse efficiency. Attached Figure Description

[0026] Figure 1 This is a flowchart of a control method for a thermal management system provided in Embodiment 1 of the present invention;

[0027] Figure 2 This is a flowchart of a control method for a thermal management system provided in Embodiment 2 of the present invention;

[0028] Figure 3 This is a schematic diagram of a compression ratio and volumetric efficiency provided in Embodiment 2 of the present invention;

[0029] Figure 4 This is a schematic diagram of a compression ratio and target rotational speed provided in Embodiment 2 of the present invention;

[0030] Figure 5This is a schematic diagram of an ambient temperature and optimal recovery time provided in Embodiment 2 of the present invention;

[0031] Figure 6 This is a schematic diagram of ambient temperature and refrigerant pressure provided in Embodiment 2 of the present invention;

[0032] Figure 7 This is a flowchart of a refrigerant recovery control method provided in Embodiment 2 of the present invention;

[0033] Figure 8 This is a flowchart of a refrigerant recharge control method provided in Embodiment 2 of the present invention;

[0034] Figure 9 This is a structural block diagram of a control device for a thermal management system provided in Embodiment 3 of the present invention;

[0035] Figure 10 This is a structural block diagram of a thermal management system provided in Embodiment 3 of the present invention. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0037] Example 1

[0038] Figure 1 This is a flowchart of a control method for a thermal management system provided in Embodiment 1 of the present invention. This embodiment is applicable to controlling thermal management systems, etc. The thermal management system is used to cool or heat a battery. The thermal management system includes: a compressor, a condenser, a gas-liquid separator, a throttling component, a solenoid valve, and a controller. The compressor outlet is sequentially connected to the condenser and the throttling component. The throttling component is connected to the refrigerant inlet of the battery through a first pipeline. The compressor inlet is connected to the gas-liquid separator. The gas-liquid separator is connected to the refrigerant outlet of the battery through a second pipeline. Both the first and second pipelines are equipped with solenoid valves. The controller is electrically connected to the compressor, the solenoid valve, and the throttling component. This method can be executed by the controller in the thermal management system. The controller can be implemented in software and / or hardware. The method specifically includes the following steps:

[0039] Step 110: Obtain the temperature and pressure of the thermal management system. The temperature includes the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the pressure includes the compressor inlet pressure and outlet pressure, and the battery refrigerant inlet pressure and refrigerant outlet pressure.

[0040] Specifically, the refrigerant inlet and outlet of the battery (which can be a refrigerant phase change cooled power battery) are equipped with pressure sensors and temperature sensors, and the inlet and outlet of the compressor are equipped with pressure sensors. The controller in the thermal management system is electrically connected to each temperature sensor and each pressure sensor to obtain the temperature collected by each temperature sensor and the pressure collected by each pressure sensor.

[0041] Step 120: When a signal associated with refrigerant recovery is detected, control the opening degree of the throttling component, open the solenoid valve, start the compressor, and adjust the compressor speed, control the compressor working time, the solenoid valve working time, and determine the amount of refrigerant lost by the thermal management system so that the thermal management system operates in the refrigerant recovery stage and completes the refrigerant recovery work.

[0042] The signals associated with refrigerant recovery include at least one of the following: refrigerant recovery start signal, battery removal / installation signal, and refrigerant leakage signal. The refrigerant recovery start signal can be an external input to the controller. The battery side can be equipped with a battery removal signal button and a refrigerant leakage detection unit electrically connected to the controller. The refrigerant leakage detection unit is used to detect the refrigerant concentration on the battery side in real time. When the refrigerant concentration exceeds the leakage judgment threshold, it outputs a refrigerant leakage signal to the control unit. The battery removal signal button is used to transmit a battery removal / installation signal to the controller during battery removal / installation. When a signal associated with refrigerant recovery is detected, the opening degree of the throttling component is controlled to its maximum allowable opening. All solenoid valves in each pipeline are opened, and the compressor is started, so that the thermal management system operates in the refrigerant recovery phase. The compressor speed is adjusted according to the temperature and pressure of the thermal management system, the compressor's operating time and the solenoid valve's operating time are controlled, and the amount of refrigerant lost by the thermal management system is determined, so that the thermal management system completes the refrigerant recovery process.

[0043] Step 130: When a signal associated with refrigerant recharge is detected, the solenoid valve is opened, and the working state of the solenoid valve is controlled according to the refrigerant inlet pressure and refrigerant outlet pressure of the battery, so that the thermal management system works in the refrigerant recharge stage and completes the refrigerant recharge work.

[0044] The signals associated with refrigerant recharge include at least one of the following: a refrigerant recharge start signal and a signal indicating insufficient refrigerant level in the battery. These signals can be externally input to the controller. When a refrigerant recharge-related signal is detected, all solenoid valves in the control lines open, initiating the refrigerant recharge phase of the thermal management system. When the minimum of the battery's refrigerant inlet pressure and refrigerant outlet pressure falls within a preset range, all solenoid valves in the control lines close, completing the refrigerant recovery process.

[0045] It should be noted that the preset range in this embodiment can be determined according to actual control requirements, and is not limited here.

[0046] The control method of the thermal management system provided in this embodiment controls the opening degree of the throttling component, the working state of the solenoid valve, and the working state of the compressor based on the acquired temperature and pressure and the detected signals. This enables the thermal management system to perform refrigerant recovery or recharge automatically without manual assistance. This solves the problems of high refrigerant loss and low refrigerant recovery and reuse efficiency in the prior art that require manual assistance, thereby reducing refrigerant loss and improving refrigerant recovery and reuse efficiency.

[0047] Example 2

[0048] Figure 2 This is a flowchart of a control method for a thermal management system provided in Embodiment 2 of the present invention. This embodiment is applicable to controlling thermal management systems, etc. The thermal management system is used to cool or heat a battery. The thermal management system includes: a compressor, a condenser, a gas-liquid separator, a throttling component, a solenoid valve, and a controller. The compressor outlet is sequentially connected to the condenser and the throttling component. The throttling component is connected to the refrigerant inlet of the battery through a first pipeline. The compressor inlet is connected to the gas-liquid separator. The gas-liquid separator is connected to the refrigerant outlet of the battery through a second pipeline. Both the first and second pipelines are equipped with solenoid valves. The controller is electrically connected to the compressor, the solenoid valves, and the throttling component. This method can be executed by the controller in the thermal management system. The controller can be implemented in software and / or hardware. The method specifically includes the following steps:

[0049] Step 210: Obtain the temperature and pressure of the thermal management system. The temperature includes the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the pressure includes the compressor inlet pressure and outlet pressure, and the battery refrigerant inlet pressure and refrigerant outlet pressure.

[0050] Specifically, pressure and temperature sensors are installed at both the refrigerant inlet and outlet of the battery, and pressure sensors are installed at both the inlet and outlet of the compressor. The controller in the thermal management system is electrically connected to each temperature sensor and each pressure sensor to obtain the temperature collected by each temperature sensor and the pressure collected by each pressure sensor.

[0051] Step 220: When a signal associated with refrigerant recovery is detected, control the opening degree of the throttling component, open the solenoid valve, start the compressor, and adjust the compressor speed. When the compressor's operating time reaches the preset first time, control the solenoid valve of the first pipeline to close.

[0052] Specifically, adjusting the compressor speed includes:

[0053] When the ratio of the compressor's outlet pressure to its inlet pressure is greater than the preset first compression ratio, the compressor speed is reduced to prevent overload.

[0054] When the ratio of the compressor's outlet pressure to its inlet pressure is less than the preset second compression ratio, the compressor speed is increased to accelerate the refrigerant recovery time.

[0055] The preset first compression ratio is greater than the preset second compression ratio, which is greater than the compressor's rated compression ratio, and the preset second compression ratio is less than the compressor's rated compression ratio. For example, the preset first compression ratio is 1.1 times the rated compression ratio, the preset second compression ratio is 0.8 times the rated compression ratio, and the preset first duration is 300 seconds. When the compressor's compression ratio ε (the ratio of the compressor's outlet pressure to its inlet pressure) is between 0.8 and 1.1 times the rated compression ratio, the compressor is controlled to maintain its current speed. When the compressor speed decreases or increases, a PID control algorithm can be used to smoothly adjust the compressor speed. For example, the target compressor speed can be dynamically adjusted using the following formula to optimize recovery efficiency:

[0056]

[0057] Among them, RPM comp_tar,k To optimize the target compressor speed, RPM comp_tar,k-1 ε is the target compressor speed before optimization. rated ε is the rated compression ratio of the compressor (preferably 8.0), k is the actual compression ratio of the compressor, and k is the rated compression ratio of the compressor. h k l Adjust the compression ratio threshold coefficient (a known quantity, k) h >1,k l <1), κ is the acceleration compensation coefficient, used to accelerate the compressor speed increase at low compression ratios (preferably, a value of 1.2), γ and δ are the system dynamic adjustment coefficients (0 < γ < 1, 0 < δ < 1), determined by the following formula: Where A and B are system characteristic constants, η v V is the volumetric efficiency of the compressor. comp For the compressor cylinder volume,

[0058] The system's rated volumetric flow rate (preferably 130 L / min). This refers to the actual speed of the compressor (preferably 3000 rpm). The inertial time constant of the compressor (preferably, 5s).

[0059] Step 230: When the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is greater than the preset first pressure threshold, calculate the optimal refrigerant recovery time based on the compressor inlet pressure and outlet pressure; the preset first pressure threshold is the minimum allowable value of the compressor's suction pressure.

[0060] The minimum allowable suction pressure of the compressor can be set according to the specific compressor model and specifications selected for the thermal management system, preferably within the range of 100–200 kPa. For example, in, T r For optimal refrigerant recovery time, T c To compensate for the time (a known quantity, which could be 30 seconds), Δn is the amount of refrigerant that needs to be recovered (a known quantity), n s Let ρ be the amount of refrigerant discharged by the compressor per minute (a known quantity), and let ρ be the refrigerant at temperature T. at The density of the saturated liquid at time T (a known quantity) at The ambient temperature on the battery side. T 1n T represents the refrigerant inlet temperature of the battery at the nth sampling time. 2n Let T be the refrigerant outlet temperature of the battery at the nth sampling time. 1k Let T be the refrigerant inlet temperature of the battery at the k-th sampling time. 2k T represents the refrigerant outlet temperature of the battery at the k-th sampling time. 1(k-1) T represents the refrigerant inlet temperature of the battery at the (k-1)th sampling time. 2(k-1) P represents the refrigerant outlet temperature of the battery at the (k-1)th sampling time, and so on; lp V is the minimum allowable suction pressure of the compressor, V is the volume of the battery-side piping (which can be obtained by looking up a preset mapping conversion table in the controller based on the battery capacity), R is the ideal gas constant, T is the refrigerant temperature, and P is the pressure of the refrigerant. s V is the inlet pressure of the compressor. s P represents the compressor's discharge capacity. batt =Min(P1, P2), where P1 is the refrigerant inlet pressure of the battery, P2 is the refrigerant outlet pressure of the battery, and RPM COMP V represents the real-time compressor speed (which can be obtained in real time). COMP Let n be the cylinder volume of the compressor (a known quantity). v Let n be the compressor volumetric efficiency (a known quantity), C be the compressor clearance volume ratio (this value can be set according to the specific compressor model and specifications selected for the system, and the range can be 0.03 to 0.90, such as 0.04), and n be the compressor clearance volume ratio (this value can be set according to the specific compressor model and specifications selected for the system, and the value can be 0.03 to 0.90, such as 0.04). ref It is a variability index (related to the properties of the refrigerant, heat dissipation during compression, etc., and its value can range from 1.05 to 1.15, such as 1.10).

[0061] Figure 3 This is a schematic diagram of compression ratio and volumetric efficiency provided in Embodiment 2 of the present invention, for reference. Figure 3The compression ratio of a compressor is inversely proportional to its volumetric efficiency; the higher the compression ratio, the lower the volumetric efficiency. Figure 4 This is a schematic diagram of a compression ratio and target rotational speed provided in Embodiment 2 of the present invention, for reference. Figure 4 The target speed of the compressor increases with the increase of the compression ratio in the acceleration zone (exemplarily, the compression ratio in the acceleration zone is less than 6.4, the coefficient α is 6.411, and β is 7.379), remains unchanged in the holding zone, and decreases with the increase of the compression ratio in the deceleration zone (exemplarily, the compression ratio in the deceleration zone is greater than 8.8). Figure 4 The red line shown corresponds to the optimized rotational speed, and the black dashed line corresponds to the adjustment threshold (the adjustment threshold for the compression ratio). Figure 5 This is a schematic diagram of an ambient temperature and optimal recovery time provided in Embodiment 2 of the present invention, for reference. Figure 5 Optimal recycling time and ambient temperature (battery-side ambient temperature T) at The optimal recovery time is inversely proportional to the ambient temperature; the higher the ambient temperature, the shorter the optimal recovery time. For example, the optimal recovery times for ambient temperatures of 10℃, 20℃, 30℃, 40℃, and 50℃ are 535s, 395s, 326s, 284s, and 256s, respectively. The optimal recovery times are 0-10℃ in the low-temperature zone, 10-30℃ in the normal-temperature zone, and greater than 30℃ in the high-temperature zone. Figure 6 This is a schematic diagram of ambient temperature and refrigerant pressure provided in Embodiment 2 of the present invention, for reference. Figure 6 Refrigerant pressure (battery-side refrigerant pressure P) batt ) and ambient temperature (battery-side ambient temperature T) at The pressure is directly proportional to the ambient temperature; the higher the ambient temperature, the greater the battery pressure.

[0062] Step 240: When the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is less than or equal to the preset first pressure threshold, or when the compressor's operating time reaches the sum of the preset second time and the optimal refrigerant recovery time, control the solenoid valve of the second pipeline to close, and when the closing time of the solenoid valve of the second pipeline reaches the preset third time, control the compressor to stop working.

[0063] For example, the second duration is preset to 60 seconds, and the third duration is preset to 3 seconds.

[0064] Step 250: When the compressor stops working for a preset fourth time period, calculate the amount of refrigerant lost by the thermal management system based on the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the refrigerant inlet pressure and refrigerant outlet pressure of the battery.

[0065] For example, the amount of refrigerant lost by the thermal management system Among them, M ref Z represents the molar mass of the refrigerant. ref Where R is the compressibility factor of the refrigerant, R is the ideal gas constant, and M is the compressibility factor of the refrigerant. refZ ref R and P are both known quantities. batt =Min(P1, P2), where P1 is the refrigerant inlet pressure of the battery, P2 is the refrigerant outlet pressure of the battery, and T at This refers to the ambient temperature on the battery side.

[0066] Furthermore, after calculating the amount of refrigerant lost by the thermal management system, the amount of refrigerant m in the thermal management system before refrigerant recovery is... last The amount of refrigerant lost by the refrigerant system (m) re The difference is used as the refrigerant quantity m after refrigerant recovery in the thermal management system. now , To update the refrigerant level in the thermal management system.

[0067] Step 260: When a signal associated with refrigerant recharge is detected, the solenoid valve is opened, and when the minimum of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is within a preset range, the solenoid valve is closed, so that the thermal management system can complete the refrigerant recharge operation.

[0068] For example, the preset range is 0.8P sa -1.2P sa In this context, "solenoid valve closed" means that all solenoid valves in all pipelines are closed.

[0069] Figure 7 This is a flowchart of a refrigerant recovery control method provided in Embodiment 2 of the present invention. Figure 8 This is a flowchart of a refrigerant recharge control method provided in Embodiment 2 of the present invention. (Reference) Figure 7 and Figure 8 P batt P represents the refrigerant pressure on the battery side, which is the minimum of the refrigerant inlet pressure and the refrigerant outlet pressure. lp This is the minimum allowable suction pressure of the compressor, i.e., the preset first pressure threshold mentioned above. The specific processes for refrigerant recovery and recharge can be found in the descriptions of steps 210-260 above, and will not be repeated here.

[0070] It should be noted that the values ​​of each parameter in this embodiment can be determined according to actual control requirements, and are not limited here.

[0071] The control method for the thermal management system provided in this embodiment controls the opening degree of the throttling component, the working state of the solenoid valve, and the working state of the compressor based on the acquired temperature, pressure, and detected signals. This enables the thermal management system to perform refrigerant recovery or recharge automatically without manual assistance. This solves the problems of high refrigerant loss and low refrigerant recovery and reuse efficiency in existing technologies that require manual assistance, thereby reducing refrigerant loss and improving refrigerant recovery and reuse efficiency. Furthermore, during the refrigerant recovery stage, the compressor speed is adjusted according to the compression ratio to optimize refrigerant recovery efficiency, adapting to different operating conditions and achieving a high refrigerant recovery efficiency of over 97%. This achieves fully automatic refrigerant recovery and recharge, reducing manual intervention and input. The system pressure is stable and the safety is high during the refrigerant recovery process.

[0072] Example 3

[0073] Figure 9 This is a structural block diagram of a control device for a thermal management system provided in Embodiment 3 of the present invention. (Reference) Figure 9 The control device of the thermal management system includes an acquisition module 310, a recovery control module 320, and a recharge control module 330. The acquisition module 310 acquires the temperature and pressure of the thermal management system, including the refrigerant inlet and outlet temperatures of the battery, and the inlet and outlet pressures of the compressor and the battery. The recovery control module 320, when detecting a signal associated with refrigerant recovery, controls the opening of the throttling component, the opening of the solenoid valve, and the starting of the compressor. It also adjusts the compressor speed, controls the compressor's operating time, and the solenoid valve's operating time based on the temperature and pressure, and determines the amount of refrigerant lost by the thermal management system, so that the thermal management system operates in the refrigerant recovery phase and completes the refrigerant recovery process. The recharge control module 330, when detecting a signal associated with refrigerant recharge, controls the opening of the solenoid valve and controls the operating state of the solenoid valve based on the battery's refrigerant inlet and outlet pressures, so that the thermal management system operates in the refrigerant recharge phase and completes the refrigerant recharge process.

[0074] Based on the above implementation method, the recycling control module 320 includes:

[0075] The first recovery control unit is used to control the solenoid valve of the first pipeline to close when the compressor's operating time reaches a preset first time.

[0076] The duration calculation unit is used to calculate the optimal refrigerant recovery time based on the compressor's inlet and outlet pressures when the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is greater than a preset first pressure threshold; the preset first pressure threshold is the minimum allowable value of the compressor's suction pressure.

[0077] The first recovery control unit is used to control the solenoid valve of the second pipeline to close when the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is less than or equal to a preset first pressure threshold, or when the compressor's operating time reaches the sum of a preset second time and the optimal refrigerant recovery time, and to control the compressor to stop working when the closing time of the solenoid valve of the second pipeline reaches a preset third time.

[0078] The refrigerant quantity calculation unit is used to calculate the amount of refrigerant lost by the thermal management system when the compressor stops working for a preset fourth time period, based on the refrigerant inlet and outlet temperatures of the battery, and the refrigerant inlet and outlet pressures of the battery.

[0079] Optionally, the refrigerant quantity calculation unit is also used to, after calculating the refrigerant quantity lost by the thermal management system, take the difference between the refrigerant quantity of the thermal management system before refrigerant recovery and the refrigerant quantity lost by the refrigerant system as the refrigerant quantity of the thermal management system after refrigerant recovery, so as to update the refrigerant quantity of the thermal management system.

[0080] Optionally, the recycling control module 320 includes:

[0081] The first speed control unit is used to control the compressor speed to decrease when the ratio of the compressor's outlet pressure to its inlet pressure is greater than a preset first compression ratio.

[0082] The second speed control unit is used to control the compressor speed to increase when the ratio of the compressor outlet pressure to the inlet pressure is less than the preset second compression ratio. The preset first compression ratio is greater than the preset second compression ratio.

[0083] Optionally, the recharge control module 330 includes:

[0084] The recharge control unit is used to close the solenoid valve when the minimum of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is within a preset range, so that the thermal management system can complete the refrigerant recharge operation.

[0085] Figure 10 This is a schematic diagram of a thermal management system provided in Embodiment 3 of the present invention. (Reference) Figure 10 The thermal management system includes: a compressor 10, a condenser 20, a gas-liquid separator 30, a throttling component 40, a solenoid valve 50, and a controller 60. The outlet of the compressor 10 is connected in sequence to the condenser 20 and the throttling component 40. The throttling component 40 is connected to the refrigerant inlet A1 of the battery through a first pipeline. The inlet of the compressor 10 is connected to the gas-liquid separator 30. The gas-liquid separator 30 is connected to the refrigerant outlet A2 of the battery through a second pipeline. Solenoid valves are provided in both the first and second pipelines. The controller is electrically connected to the compressor, the solenoid valve, and the throttling component. The control method described in any embodiment of the present invention is executed by the controller.

[0086] The system includes a compressor 10 for maintaining high and low pressure during operation; a condenser 20 for condensing the high-temperature, high-pressure refrigerant discharged from the compressor 10; a throttling device 40 for reducing the refrigerant pressure to a low-pressure state; and a gas-liquid separator 30 for storing the recovered refrigerant and preventing the risk of compressor liquid slugging during the recovery process. The thermal management system is used to cool or heat batteries, such as refrigerant phase-change cooled power batteries, which have internal cold plate heat exchangers for refrigerant flow and heat exchange. The throttling device 40 may include an electronic expansion valve (EEV), and the condenser 20 may include a condenser and a fan, with the fan located on one side of the condenser. The outlet of the compressor 10 is sequentially connected to the condenser and the throttling device. Control of the thermal management system, such as the control of refrigerant recovery and refrigerant recharging, can be found in the descriptions of any of the above embodiments and will not be repeated here.

[0087] In addition, the thermal management system also includes a data storage unit 70, a display unit 80, a refrigerant leak detection unit 90, and a battery removal signal button 91 connected to the controller 60. The display unit 80 may include a touch screen for information interaction. The refrigerant leak detection unit 90 and the battery removal signal button 91 are located on the battery side. The data storage unit 70 is used to record the refrigerant recovery process and refrigerant quantity changes to record detailed refrigerant recovery data for easy system maintenance and management. Data received and processed by the controller 60 can be transmitted to and stored in the storage unit 70. The display unit 80 is used to display relevant information during system operation and running. The controller 60 can transmit the working stages of the thermal management system, such as the refrigerant recovery stage or the refrigerant recharging stage, as well as the temperatures of each temperature sensor and the pressures of each pressure sensor, to the display unit 80 for display, so that relevant personnel can intuitively understand the working status of the thermal management system.

[0088] Optionally, the solenoid valve 50 includes a first solenoid valve V1 and a second solenoid valve V2, wherein the first solenoid valve V1 is located in the first pipeline and the second solenoid valve V2 is located in the second pipeline.

[0089] Specifically, the first solenoid valve V1 is a liquid-line solenoid valve, located in the pipeline connecting the throttling component 40 and the refrigerant inlet A1 of the battery, and close to the throttling component 40, such as at the outlet of the throttling component 40. The second solenoid valve V2 is a gas-line solenoid valve, located in the pipeline connecting the gas-liquid separator 30 and the refrigerant outlet A2 of the battery, and close to the gas-liquid separator 30, such as at the inlet of the gas-liquid separator 30. By opening and closing the first solenoid valve V1 and the second solenoid valve V2, the flow of refrigerant in their respective pipelines can be controlled.

[0090] Optionally, pressure sensors and temperature sensors are installed at both the refrigerant inlet A1 and the refrigerant outlet A2, and pressure sensors are installed at both the outlet and inlet of the compressor 10. Each pressure sensor and each temperature sensor is electrically connected to the controller.

[0091] Specifically, a pressure sensor P1 and a temperature sensor T1 are installed at the refrigerant inlet A1, a pressure sensor P2 and a temperature sensor T2 are installed at the refrigerant outlet A2, a pressure sensor Pd is installed at the outlet of the compressor 10, a pressure sensor Ps is installed at the inlet of the compressor 10, and a pressure sensor P3 and a temperature sensor T3 are installed in the pipeline between the condensing unit 20 and the throttling component 40. Each pressure sensor is used to collect the pressure at its respective location, and each temperature sensor is used to collect the temperature at its respective location. The controller controls the thermal management system, such as refrigerant recovery control and refrigerant recharge control, based on the pressure collected by each pressure sensor and the temperature collected by each temperature sensor. The specific control process can be referred to the description of any of the above embodiments, and will not be repeated here.

[0092] The control device and thermal management system provided in this embodiment belong to the same inventive concept as the control method of the thermal management system provided in any embodiment of the present invention, and have corresponding beneficial effects. For technical details not covered in this embodiment, please refer to the control method of the thermal management system provided in any embodiment of the present invention.

[0093] Example 4

[0094] Embodiment 4 of the present invention provides a computer-readable storage medium having a computer program stored thereon. When executed by a processor, the program implements the control method of the thermal management system provided in the embodiments of the present invention, the method comprising:

[0095] The temperature and pressure of the thermal management system are obtained, including the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the pressure including the compressor inlet pressure and outlet pressure, and the refrigerant inlet pressure and refrigerant outlet pressure of the battery.

[0096] When a signal associated with refrigerant recovery is detected, the opening degree of the throttling component, the opening of the solenoid valve, and the starting of the compressor are controlled. The compressor speed is adjusted according to temperature and pressure, the operating time of the compressor and the operating time of the solenoid valve are controlled, and the amount of refrigerant lost by the thermal management system is determined so that the thermal management system operates in the refrigerant recovery stage and completes the refrigerant recovery work.

[0097] When a signal associated with refrigerant recharge is detected, the control solenoid valve opens, and the working state of the solenoid valve is controlled according to the refrigerant inlet pressure and refrigerant outlet pressure of the battery, so that the thermal management system works in the refrigerant recharge stage and completes the refrigerant recharge work.

[0098] The computer storage medium of this invention can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0099] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0100] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including—but not limited to—wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0101] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or terminal. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0102] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, rearrangements, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A control method for a thermal management system, characterized in that, The thermal management system is used to cool or heat the battery. The thermal management system includes: a compressor, a condenser, a gas-liquid separator, a throttling component, a solenoid valve, and a controller. The compressor outlet is sequentially connected to the condenser and the throttling component. The throttling component is connected to the refrigerant inlet of the battery via a first pipeline. The compressor inlet is connected to the gas-liquid separator. The gas-liquid separator is connected to the refrigerant outlet of the battery via a second pipeline. The solenoid valve is installed in both the first and second pipelines. The controller is electrically connected to the compressor, the solenoid valve, and the throttling component. The control method is executed by the controller. The control method includes: The temperature and pressure of the thermal management system are obtained, wherein the temperature includes the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the pressure includes the inlet pressure and outlet pressure of the compressor, and the refrigerant inlet pressure and refrigerant outlet pressure of the battery; When a signal associated with refrigerant recovery is detected, the opening degree of the throttling component, the opening of the solenoid valve, and the starting of the compressor are controlled. The speed of the compressor is adjusted according to the temperature and pressure, the working time of the compressor and the working time of the solenoid valve are controlled, and the amount of refrigerant lost by the thermal management system is determined so that the thermal management system operates in the refrigerant recovery stage and completes the refrigerant recovery work. When a signal associated with refrigerant recharge is detected, the solenoid valve is opened, and the working state of the solenoid valve is controlled according to the refrigerant inlet pressure and refrigerant outlet pressure of the battery, so that the thermal management system operates in the refrigerant recharge stage and completes the refrigerant recharge work.

2. The control method for the thermal management system according to claim 1, characterized in that, The steps of adjusting the compressor speed, controlling the compressor's operating time, and controlling the solenoid valve's operating time based on the temperature and pressure, as well as determining the amount of refrigerant lost by the thermal management system, include: When the compressor operates for a preset first duration, the solenoid valve of the first pipeline is closed. When the minimum value of the refrigerant inlet pressure and the refrigerant outlet pressure of the battery is greater than a preset first pressure threshold, the optimal refrigerant recovery time is calculated based on the compressor inlet pressure and the compressor outlet pressure; the preset first pressure threshold is the minimum allowable value of the compressor suction pressure. When the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is less than or equal to the preset first pressure threshold, or when the working time of the compressor reaches the sum of the preset second time and the optimal refrigerant recovery time, the solenoid valve of the second pipeline is controlled to close, and when the closing time of the solenoid valve of the second pipeline reaches the preset third time, the compressor is controlled to stop working. When the compressor stops working for a preset fourth time period, the amount of refrigerant lost by the thermal management system is calculated based on the refrigerant inlet temperature and refrigerant outlet temperature of the battery, and the refrigerant inlet pressure and refrigerant outlet pressure of the battery.

3. The control method for the thermal management system according to claim 2, characterized in that, After calculating the refrigerant loss of the thermal management system, the following steps are included: The difference between the amount of refrigerant in the thermal management system before refrigerant recovery and the amount of refrigerant lost by the refrigerant system is used as the amount of refrigerant in the thermal management system after refrigerant recovery, so as to update the amount of refrigerant in the thermal management system.

4. The control method for the thermal management system according to claim 2, characterized in that, The amount of refrigerant lost by the thermal management system Among them, M ref Z represents the molar mass of the refrigerant. ref Where R is the compressibility factor of the refrigerant, R is the ideal gas constant, and M is the compressibility factor of the refrigerant. ref Z ref R and P are both known quantities. batt =Min(P1, P2), where P1 is the refrigerant inlet pressure of the battery, P2 is the refrigerant outlet pressure of the battery, and T at The ambient temperature of the battery is related to the average of the refrigerant inlet temperature and the refrigerant outlet temperature of the battery.

5. The control method for the thermal management system according to claim 1, characterized in that, Adjusting the speed of the compressor includes: When the ratio of the compressor's outlet pressure to its inlet pressure is greater than a preset first compression ratio, the compressor's speed is controlled to decrease. When the ratio of the compressor's outlet pressure to its inlet pressure is less than a preset second compression ratio, the compressor's speed is controlled to increase, and the preset first compression ratio is greater than the preset second compression ratio.

6. The control method for the thermal management system according to claim 5, characterized in that, The preset first compression ratio is greater than the rated compression ratio of the compressor, and the preset second compression ratio is less than the rated compression ratio of the compressor.

7. The control method for the thermal management system according to claim 1, characterized in that, The method of controlling the operating state of the solenoid valve based on the refrigerant inlet pressure and refrigerant outlet pressure of the battery includes: When the minimum value of the refrigerant inlet pressure and refrigerant outlet pressure of the battery is within a preset range, the solenoid valve is controlled to close, so that the thermal management system can complete the refrigerant recharge operation.

8. A thermal management system, characterized in that, include: The system comprises a compressor, a condenser, a gas-liquid separator, a throttling device, a solenoid valve, and a controller. The outlet of the compressor is sequentially connected to the condenser and the throttling device. The throttling device is connected to the refrigerant inlet of the battery via a first pipeline. The inlet of the compressor is connected to the gas-liquid separator. The gas-liquid separator is connected to the refrigerant outlet of the battery via a second pipeline. The solenoid valve is installed in both the first and second pipelines. The controller is electrically connected to the compressor, the solenoid valve, and the throttling device. The control method described in any one of claims 1-7 is executed by the controller.

9. The thermal management system according to claim 8, characterized in that, The solenoid valve includes a first solenoid valve and a second solenoid valve, wherein the first solenoid valve is located in the first pipeline and the second solenoid valve is located in the second pipeline.

10. The thermal management system according to claim 9, characterized in that, Both the refrigerant inlet and the refrigerant outlet are equipped with pressure sensors and temperature sensors, and both the compressor outlet and inlet are equipped with pressure sensors. Each pressure sensor and each temperature sensor is electrically connected to the controller.

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