Phase change material battery temperature control system and control method thereof

Abstract

The invention belongs to the technical field of battery temperature control, and particularly relates to a phase change material battery temperature control system and a control method thereof. By introducing a natural environment cold source and utilizing natural heat exchange between the phase change material and ambient air, efficient temperature control of the battery is realized. The system adopts air liquid cooling heat dissipation in a medium-temperature environment, compressor starting is avoided, refrigeration power consumption is reduced, and the energy utilization rate of the energy storage system is improved. Meanwhile, due to the cold storage function of the phase change material, the size of the heat exchanger and the air volume of a fan are reduced, the refrigerating and heating energy efficiency is improved, the product size and operation noise are reduced, and the product performance and application comfort are improved. The invention provides a solution with low energy consumption, low noise and high temperature control precision for the field of battery temperature control.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery temperature control, and in particular relates to a phase change material battery temperature control system and a control method thereof. Background Art

[0002] As energy storage equipment is increasingly used in power systems, transportation and other fields, battery temperature control technology has become one of the key technologies to ensure the safe and reliable operation of energy storage systems. At present, common battery temperature control technologies are mainly divided into two methods: air cooling and liquid cooling.

[0003] Air cooling technology: uses a fan to take away the heat generated by the battery. It has a simple structure and low cost, but has low heat dissipation efficiency, uneven temperature distribution, and is easily affected by ambient temperature.

[0004] Liquid cooling technology: uses liquid coolant to take away the heat generated by the battery. It has high heat dissipation efficiency and uniform temperature distribution, but the system is complex, the cost is high, the operating energy consumption is large, and the noise is relatively high.

[0005] At present, the existing battery temperature control technology has the following main defects:

[0006] High energy consumption: Existing liquid cooling systems usually use compressor refrigeration, which consumes a lot of energy and reduces the overall energy utilization of the energy storage system.

[0007] Loud noise: The operation of the compressor and fan will generate loud noise, affecting the use environment.

[0008] Insufficient temperature control accuracy: The existing temperature control system has limited control accuracy for battery temperature and cannot meet the needs of certain specific application scenarios. Summary of the invention

[0009] The purpose of the present invention is to provide a phase change material battery temperature control system and a control method thereof, so as to solve the problems of high energy consumption, high noise and insufficient temperature control accuracy in the battery temperature control system in the prior art.

[0010] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0011] In a first aspect, the present invention provides a phase change material battery temperature control system, the system comprising a water inlet and a water outlet connected to a battery thermal management system; and:

[0012] The first circulation system includes a condenser connected between the water inlet and the water outlet, a heat exchange component, a compressor, and a phase change material 1 arranged between the condenser and the compressor; when the ambient temperature value is higher than the first preset temperature value of the water outlet, the compressor refrigeration mode is entered;

[0013] The second circulation system includes a cooler and a phase change material connected between the water inlet and the water outlet; when the ambient temperature value is lower than the first preset temperature value of the water outlet, the air-liquid cooling mode is entered;

[0014] The control module is used to switch to the first circulation system or the second circulation system according to the relationship between the water outlet temperature value and the first preset water outlet temperature value.

[0015] Furthermore, the system also includes:

[0016] An electric three-way valve and a PTC heater provided at the inlet side of the first circulation system and the second circulation system, and a water pump provided between the water inlet and the electric three-way valve for driving the flow of heat exchange medium;

[0017] When the water outlet temperature value is lower than the second preset water outlet temperature value, the PTC heater is started to heat the heat exchange medium, and the system enters the heating mode;

[0018] Wherein, the first preset temperature value is greater than the second preset temperature value.

[0019] Furthermore, the system also includes a fan, which is arranged on the air side of the cooler and is used to perform heat exchange between the heat exchange medium flowing through the cooler and the air.

[0020] Furthermore, in the first circulation system, the heat exchange component includes a plate heat exchanger and an electronic expansion valve; the compressor is used to send the compressed hot steam into the phase change material 1 for pre-cooling; the condenser is used to receive the pre-cooled hot steam and release heat to the phase change material 1 and the air driven by the fan to form a liquid refrigerant; the electronic expansion valve is used to transform the liquid refrigerant into wet steam; the plate heat exchanger is used to receive the wet steam and evaporate it into a gaseous refrigerant; the compressor is also used to inhale the gaseous refrigerant to form a refrigerant circulation cooling.

[0021] Furthermore, the freezing point temperature of the phase change material 1 is higher than the freezing point temperature of the phase change material 2.

[0022] Furthermore, the control module includes:

[0023] A standby switching unit, used to control the system to enter a standby state when the battery temperature difference is higher than a third preset temperature value;

[0024] A mode switching unit, configured to switch to the first circulation system or the second circulation system when the water inlet temperature value is higher than the first preset temperature value of the water outlet plus the set value, or to enter the water pump circulation mode when the water inlet temperature value is between the second preset temperature value and the first preset temperature value of the water outlet plus the set value;

[0025] An environmental temperature control unit is used to switch to the second circulation system when the environmental temperature value is higher than the first preset temperature value, and otherwise switch to the first circulation system.

[0026] Furthermore, the system also includes:

[0027] A first temperature sensor for detecting the ambient temperature value, a second temperature sensor for detecting the water outlet temperature value, and a third temperature sensor for detecting the water inlet temperature value, and a signal processing unit connected to each sensor, the signal processing unit is used to receive the temperature signal of each sensor and transmit it to the control module to control the switching of each mode and the start and stop of each system.

[0028] In a second aspect, the present invention provides a control method for a phase change material battery temperature control system as described in any one of the above items, comprising the following steps:

[0029] S1. Detect and read the battery temperature difference, ambient temperature and water outlet temperature;

[0030] S2, judging whether the battery temperature difference is higher than the third temperature preset value, if so, controlling the temperature control system to enter the standby state; otherwise, judging whether the water outlet temperature value is higher than the first preset temperature value plus the set value, if so, entering the cooling mode; otherwise, judging whether the water outlet temperature is lower than the second preset temperature value, if so, entering the heating mode; otherwise, judging whether the ambient temperature is higher than the first preset temperature value, if so, entering the compressor cooling mode; otherwise, entering the air-liquid cooling mode;

[0031] S3. According to the judgment result, the electric three-way valve is controlled to switch the first circulation system or the second circulation system, the start and stop of the compressor, the water pump and the PTC heater are controlled, and the operating state of the fan is controlled.

[0032] The beneficial effects of the present invention are:

[0033] 1. The present invention introduces a natural cold source to cool the battery in a medium temperature environment, avoiding the high energy consumption caused by the start-up of a traditional compressor, thereby significantly improving the energy utilization rate of the energy storage system. The use of air-liquid cooling not only reduces the cooling power consumption, but also reduces the operating noise of the system, improving the overall environmental adaptability and economy of the system.

[0034] 2. The present invention utilizes the natural heat exchange between phase change materials and ambient air to effectively realize the cold storage function of phase change materials, thereby reducing the size of the heat exchanger and the air volume of the cooling fan, further improving the energy efficiency of cooling and heating. This innovation not only reduces the size and operating noise of the product, but also improves the performance and comfortable applicability of the product, providing an efficient and environmentally friendly solution for the field of battery temperature control. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A working principle diagram of a phase change material battery temperature control system provided in an embodiment of the present application;

[0036] Figure 2 A schematic diagram of an operation flow of a phase change material battery temperature control system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0038] Example 1

[0039] like Figure 1-2 As shown, this embodiment proposes a phase change material battery temperature control system, the system includes a water inlet and a water outlet connected to the battery thermal management system; the system mainly includes the following components:

[0040] The first circulation system (refrigeration system): includes the compressor, condenser, fan, electronic expansion valve, plate heat exchanger and phase change material 1. These components work together to achieve heat exchange and temperature control in the compressor refrigeration mode.

[0041] More specifically, the first circulation system includes a condenser connected between a water inlet and a water outlet, a heat exchange component, a compressor, and a phase change material 1 disposed between the condenser and the compressor; when the ambient temperature value is higher than the first preset temperature value of the water outlet (the corresponding battery pack needs to be cooled), the phase change material 1 is used to perform heat exchange with the heat exchange medium circulating through the second condensation component, the first heat exchange component, and the compressor to cool the heat exchange medium, and the system enters the compressor refrigeration mode;

[0042] The second circulation system (water circulation system): includes a water pump, an electric three-way valve, a cooler, a PTC heater, an inlet and outlet water temperature sensor, and a phase change material. This system is responsible for circulating the heat exchange medium (such as a coolant) and sending the temperature-regulated coolant to the battery side through different cooling or heating modes.

[0043] More specifically, the second circulation system includes a cooler and phase change material 2 connected between the water inlet and the water outlet; when the ambient temperature value is lower than the first preset temperature value of the water outlet, the phase change material 2 is used to exchange heat with the heat exchange medium flowing through the cooler to cool the heat exchange medium, and the system enters the air-liquid refrigeration mode.

[0044] Control module: used to switch different working modes and control the start and stop of related components according to real-time temperature data (such as ambient temperature, water outlet temperature, etc.) and preset temperature values.

[0045] Sensors: including a first temperature sensor for detecting the ambient temperature, a second temperature sensor for detecting the water outlet temperature, and a third temperature sensor for detecting the water inlet temperature. These sensors transmit data to the control module in real time for decision making.

[0046] Further preferably, the system also includes: an electric three-way valve and a PTC heater arranged on the inlet side of the first circulation system and the second circulation system, and a water pump arranged between the water inlet and the electric three-way valve for driving the flow of the heat exchange medium; when the water outlet temperature value is lower than the second preset temperature value of the water outlet (the corresponding battery pack needs to be heated), the PTC heater is started to heat the heat exchange medium, and the system enters the heating mode; wherein the first preset temperature value is greater than the second preset temperature value.

[0047] Further preferably, the system further comprises a fan, which is arranged on the air side of the cooler and is used for performing heat exchange between the heat exchange medium flowing through the cooler and the air.

[0048] Further preferably, in the first circulation system, the heat exchange component includes a plate heat exchanger and an electronic expansion valve; the compressor is used to send the compressed hot steam into the phase change material 1 for pre-cooling; the condenser is used to receive the pre-cooled hot steam and release heat to the phase change material 1 and the air driven by the fan to form a liquid refrigerant; the electronic expansion valve is used to transform the liquid refrigerant into wet steam; the plate heat exchanger is used to receive the wet steam and evaporate it into a gaseous refrigerant; the compressor is also used to inhale the gaseous refrigerant to form a refrigerant circulation cooling.

[0049] Further preferably, the freezing point temperature of the phase change material 1 is higher than the freezing point temperature of the phase change material 2.

[0050] It should be noted that in this embodiment, phase change material 1 and phase change material 2 should have suitable solidification temperatures to meet the cooling and heating requirements under different ambient temperatures. Normally, the solidification temperature of phase change material 1 is higher than that of phase change material 2. Exemplarily, the solidification temperature of phase change material 1 is 35°C, and the solidification temperature of phase change material 2 is 18°C. When the ambient temperature is lower than the solidification temperature, the phase change material releases a large amount of latent heat and solidifies from liquid phase to solid phase. During this process, the temperature of the phase change material remains relatively constant, which makes it an efficient thermal energy storage medium.

[0051] Further preferably, the control module includes:

[0052] A standby switching unit, used to control the system to a standby state when the battery temperature difference is higher than a third preset temperature value;

[0053] A mode switching unit is used to switch to the first circulation system or the second circulation system when the water inlet temperature value is higher than the first preset temperature value of the water outlet plus the set value, otherwise when the water inlet temperature value is between the second preset temperature value and the first preset temperature value of the water outlet plus the set value, enter the water pump circulation mode; wherein, in the water pump circulation mode, other loads of the temperature control unit are turned off, and only the water pump is turned on to circulate the water circuit;

[0054] The environment temperature control unit is used to switch to the second circulation system when the environment temperature value is higher than the first preset temperature value, and otherwise switch to the first circulation system.

[0055] Further preferably, the system further comprises:

[0056] A first temperature sensor for detecting the ambient temperature value, a second temperature sensor for detecting the water outlet temperature value, and a third temperature sensor for detecting the water inlet temperature value, and a signal processing unit connected to each sensor, the signal processing unit is used to receive the temperature signal of each sensor and transmit it to the control module to control the switching of each mode and the start and stop of each system.

[0057] The description of some technical features in this embodiment is as follows:

[0058] When the battery in the battery pack needs to be cooled, the temperature control system sets the target water outlet temperature to T 制冷；

[0059] When the battery in the battery pack needs to be heated up, the temperature control system sets the target water outlet temperature to T 制热；

[0060] The freezing point temperature of phase change material 1 is T 冰1 , the freezing point temperature of phase change material 2 is T 冰2 , T 冰1 >T 冰2 ;

[0061] The ambient temperature sensor detects the temperature in real time as T 环境 ;

[0062] Low power consumption ambient temperature T Low , lower than T 制冷 ;

[0063] The outlet water temperature sensor detects the real-time water temperature as T 水温 ;

[0064] According to the above embodiment of the present invention, the temperature control system has the following specific working modes and operation procedures:

[0065] ① Standby state: After the system is powered on, it first enters the standby state. At this time, the control module detects the battery temperature difference. If the battery temperature difference is higher than the preset third temperature value (the temperature is set according to the battery pack type), the system continues to be in the standby state; otherwise, the subsequent mode judgment is performed based on the water outlet temperature and the ambient temperature.

[0066] ②Cooling mode:

[0067] When the outlet temperature is higher than the preset first temperature value plus a certain set value (such as T 水温 >T 制冷 +1), the system enters cooling mode.

[0068] If the ambient temperature is lower than the low power consumption ambient temperature (such as T 环境 ≤T Low ), it enters the air-liquid cooling mode. There is no need to start the high-power consumption components of the compressor. The water pump drives the coolant to flow through the electric three-way valve-cooler-phase change material-PTC heater. The fan rotates the coolant in the cooler to exchange heat indirectly with the air flowing through it, dissipating the heat in the coolant to the air flowing through it, achieving the purpose of cooling, and then sending it to the battery side.

[0069] If the ambient temperature is higher than T Low (such as T 环境 >T Low), the air-liquid refrigeration mode cannot continuously cool the refrigerant, and the compressor refrigeration mode is entered. The electric three-way valve is switched to the vertical path to ensure that the water pump drives the refrigerant to flow into the plate heat exchanger; the electric energy input starts the compressor, sucks in the low-pressure and low-temperature refrigerant vapor, and increases its pressure and temperature through mechanical compression. The compressed high-pressure hot steam is sent to the phase change material for pre-cooling. Then entering the condenser, the high-temperature and high-pressure refrigerant vapor releases heat to the phase change material and the air driven by the fan, thereby condensing into a high-pressure liquid. When the high-pressure liquid refrigerant passes through the electronic expansion valve, the pressure drops suddenly, causing part of the refrigerant to flash into steam, forming a low-temperature and low-pressure wet steam mixture, and entering the plate heat exchanger. The refrigerant absorbs the heat of the refrigerant, thereby evaporating into low-pressure and low-temperature steam, which is sucked in by the compressor again to complete a cycle. The refrigeration system and the water circulation system work continuously in a cycle to achieve continuous cooling of the refrigerant and send it to the battery side.

[0070] ③ Heating mode: When the water outlet temperature is lower than the preset second temperature value, the PTC heater is started to heat the heat exchange medium, and the system enters the heating mode.

[0071] ④Mode switching:

[0072] The control module switches the mode according to the real-time data of the water outlet temperature and the ambient temperature, as well as the preset temperature value. Specifically, a smooth switch between different working modes is achieved through a mode switching unit, an ambient temperature control unit, etc.

[0073] During the mode switching process, the electric three-way valve is responsible for switching different circulation systems (the first circulation system or the second circulation system). The start and stop of the compressor, water pump and PTC heater are controlled by the control module, and the operating status of the fan is also adjusted as needed.

[0074] In the above embodiment, the phase change material 1 and the phase change material in this application have the following principle flow:

[0075] For phase change material 1, phase change material 1 in T 环境 ≤T 冰1 Under the condition that the compressor refrigeration mode is not working, the phase change material 1 is equivalent to an energy storage unit, which continuously releases heat into the air and changes from liquid phase to solid phase to store cold source; when the compressor refrigeration mode is working, the solid phase change material 1 absorbs the heat of the high-temperature and high-pressure refrigerant discharged by the compressor, gradually turns into liquid to release the heat of solution, and forms a bridge for heat exchange. By utilizing the cold storage and heat exchange bridge of the phase change material 1, the heat exchange demand of the condenser can be reduced, the size of the heat exchanger can be reduced, and the fan speed can be reduced, which has the effect of energy saving and noise reduction.

[0076] For phase change material 2, when the air-liquid refrigeration mode is not working, phase change material 2 is equivalent to an energy storage unit, continuously releasing heat into the air, and changing from liquid phase to solid phase to store cold source; when the air-liquid refrigeration mode is working, the solid phase phase change material 2 absorbs the heat from the coolant on the battery side, gradually turns into liquid to release the heat of dissolution, and forms a bridge for heat exchange. By utilizing the cold storage and heat exchange bridge of phase change material 2, the heat exchange demand of the cooler can be reduced, the size of the cooler can be reduced, the fan speed can be reduced, and the effect of energy saving and noise reduction can be achieved.

[0077] In another embodiment of the present invention, a control method for a phase change material battery temperature control system as described above is proposed, comprising the following steps:

[0078] S1. Detect and read the battery temperature difference, ambient temperature and water outlet temperature;

[0079] S2, judging whether the battery temperature difference is higher than the third temperature preset value, if so, controlling the temperature control system to enter the standby state; otherwise, judging whether the water outlet temperature value is higher than the first preset temperature value plus the set value, if so, entering the cooling mode; otherwise, judging whether the water outlet temperature is lower than the second preset temperature value, if so, entering the heating mode; otherwise, judging whether the ambient temperature is higher than the first preset temperature value, if so, entering the compressor cooling mode; otherwise, entering the air-liquid cooling mode;

[0080] S3. According to the judgment result, the electric three-way valve is controlled to switch the first circulation system or the second circulation system, the start and stop of the compressor, the water pump and the PTC heater are controlled, and the operating state of the fan is controlled.

[0081] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A phase change material battery temperature control system, characterized in that: The system includes a water inlet and a water outlet connected to the battery thermal management system; as well as: The first circulation system includes a condenser connected between the water inlet and the water outlet, a heat exchange component, a compressor, and a phase change material 1 disposed between the condenser and the compressor; When the ambient temperature is higher than the first preset temperature of the water outlet, the compressor cooling mode is entered; A second circulation system, comprising a cooler and a phase change material 2 connected between the water inlet and the water outlet; When the ambient temperature is lower than the first preset temperature of the water outlet, the air-liquid cooling mode is entered; The control module is used to switch to the first circulation system or the second circulation system according to the relationship between the water outlet temperature value and the first preset water outlet temperature value.

2. A phase change material battery temperature control system according to claim 1, characterized in that: The system further comprises: An electric three-way valve and a PTC heater provided at the inlet side of the first circulation system and the second circulation system, and a water pump provided between the water inlet and the electric three-way valve for driving the flow of heat exchange medium; When the water outlet temperature value is lower than the second preset water outlet temperature value, the PTC heater is started to heat the heat exchange medium, and the system enters the heating mode; Wherein, the first preset temperature value is greater than the second preset temperature value.

3. A phase change material battery temperature control system according to claim 1, characterized in that: The system further comprises a fan, which is arranged on the air side of the cooler and is used for performing heat exchange between the heat exchange medium flowing through the cooler and the air.

4. A phase change material battery temperature control system according to claim 3, characterized in that: In the first circulation system, the heat exchange component includes a plate heat exchanger and an electronic expansion valve; the compressor is used to send the compressed hot steam into the phase change material 1 for pre-cooling; the condenser is used to receive the pre-cooled hot steam and release heat to the phase change material 1 and the air driven by the fan to form a liquid refrigerant; the electronic expansion valve is used to transform the liquid refrigerant into wet steam; the plate heat exchanger is used to receive the wet steam and evaporate it into a gaseous refrigerant; the compressor is also used to inhale the gaseous refrigerant to form a refrigerant circulation cooling.

5. A phase change material battery temperature control system according to claim 1, characterized in that: The freezing point temperature of the phase change material 1 is higher than the freezing point temperature of the phase change material 2.

6. A phase change material battery temperature control system according to claim 4, characterized in that: The control module comprises: A standby switching unit, used to control the system to enter a standby state when the battery temperature difference is higher than a third preset temperature value; A mode switching unit, configured to switch to the first circulation system or the second circulation system when the water inlet temperature value is higher than the first preset temperature value of the water outlet plus the set value, or to enter the water pump circulation mode when the water inlet temperature value is between the second preset temperature value and the first preset temperature value of the water outlet plus the set value; An environmental temperature control unit is used to switch to the second circulation system when the environmental temperature value is higher than the first preset temperature value, and otherwise switch to the first circulation system.

7. A phase change material battery temperature control system according to claim 6, characterized in that: The system further comprises: A first temperature sensor for detecting the ambient temperature value, a second temperature sensor for detecting the water outlet temperature value, and a third temperature sensor for detecting the water inlet temperature value, and a signal processing unit connected to each sensor, the signal processing unit is used to receive the temperature signal of each sensor and transmit it to the control module to control the switching of each mode and the start and stop of each system.

8. A control method for a phase change material battery temperature control system according to any one of claims 1 to 7, characterized in that: The steps include: S1. Detect and read the battery temperature difference, ambient temperature and water outlet temperature; S2, determining whether the battery temperature difference is higher than a third temperature preset value, and if so, controlling the temperature control system to enter a standby state; Otherwise, when judging whether the water outlet temperature is higher than the first preset temperature value plus the set value, if so, enter the cooling mode; otherwise, judge whether the water outlet temperature is lower than the second preset temperature value, if so, enter the heating mode; otherwise, judge whether the ambient temperature is higher than the first preset temperature value, if so, enter the compressor cooling mode; otherwise, enter the air-liquid cooling mode; S3. According to the judgment result, the electric three-way valve is controlled to switch the first circulation system or the second circulation system, the start and stop of the compressor, the water pump and the PTC heater are controlled, and the operating state of the fan is controlled.

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