Methods for controlling temperature, equipment and devices for battery packs, and new energy vehicles.

Abstract

Invention details;

Description

Battery pack temperature control method, device, equipment and new energy vehicle

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on April 28, 2023, with application number 202310479144.9 and application name “Temperature control method, device, equipment and new energy vehicle for battery pack”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of new energy vehicles, and specifically to a temperature control method, device, equipment and new energy vehicle for a battery pack. Background Art

[0003] New energy vehicles offer significant advantages in improving energy efficiency and reducing carbon emissions, and their popularity and market share in the consumer market are gradually increasing. With the increasing popularity of new energy vehicles, the demand for their range is also increasing. However, due to vehicle space constraints, increasing battery size is not feasible. Therefore, increasing the energy density of power batteries has become a long-standing and effective solution in the industry to improve the range of new energy vehicles. This increase in power battery energy density also creates the problem of increased heat generation and high temperatures, which negatively impacts battery capacity and lifespan.

[0004] Currently, new energy vehicles primarily use battery packs as their energy source. These systems typically dynamically adjust the cooling level based on the air conditioning heat load and battery cooling requirements to ensure vehicle comfort and save energy. However, related technologies typically control the cooling level of the air conditioning compressor based on the maximum temperature of the battery pack, resulting in uneven temperature distribution across the battery pack. This can lead to inconsistent discharge and even thermal runaway, shortening the battery pack's service life.

[0005] Summary of the Invention

[0006] The purpose of this application is to provide a temperature control method, device, equipment and new energy vehicle for a battery pack, which can finely control the temperature inside the battery pack, avoid thermal runaway of the battery pack due to uneven discharge, and increase the service life of the battery pack.

[0007] In the first aspect, an embodiment of the present application provides a temperature control method for a battery pack, which is applied to a passenger compartment thermal management circuit and a battery pack thermal management circuit arranged in parallel. The passenger compartment thermal management circuit includes a main circuit and a first branch circuit and a second branch circuit connected to the main circuit and in parallel. The main circuit includes a compressor, a condenser, and a liquid reservoir arranged in sequence. The first branch circuit includes an evaporator and an electronic expansion valve connected to the inlet of the evaporator. The second branch circuit includes a cooler, a thermal expansion valve connected to the inlet of the cooler, and a stop valve connected to the thermal expansion valve. The battery pack thermal management circuit includes a battery pack, a first water pump, and a cooler arranged in sequence. The cooler The side of the cooler facing the evaporator is refrigerant, and the side of the cooler facing the battery pack is coolant. A plurality of temperature sensors are provided in the battery pack to detect the temperature of various positions in the battery pack. The temperature control method includes: obtaining the maximum temperature value and the minimum temperature value in the battery pack; comparing whether the difference between the maximum temperature value and the minimum temperature value is greater than the design threshold, and whether the maximum temperature value is greater than or equal to the first tolerance temperature threshold of the battery pack; if so, turning on the compressor, the first water pump and the shut-off valve to enable the first water pump to drive the coolant into the battery pack, and exchange the heat generated by the battery pack with the refrigerant in the cooler.

[0008] Furthermore, the temperature control method also includes: comparing whether the maximum temperature value is less than or equal to a second tolerance temperature threshold of the battery pack; if so, closing the shut-off valve and reducing the speed of the compressor, wherein the first tolerance temperature threshold is greater than the second tolerance temperature threshold.

[0009] Furthermore, the temperature control method further includes: comparing whether the difference between the maximum temperature value and the minimum temperature value is less than or equal to a design threshold and greater than 0; if so, turning off the first water pump.

[0010] Furthermore, the temperature control method also includes: obtaining the temperature value of the passenger compartment; if the temperature value of the passenger compartment is greater than the target threshold, turning on the electronic expansion valve and the compressor to cool the passenger compartment, and adjusting the opening of the electronic expansion valve and the speed of the compressor according to the temperature change of the battery pack.

[0011] Furthermore, adjusting the opening of the electronic expansion valve and the speed of the compressor according to the temperature change of the battery pack includes: when the difference between the maximum temperature value and the minimum temperature value of the battery pack is greater than the design threshold, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold of the battery pack, the opening of the electronic expansion valve is increased to the first opening, and the speed of the compressor is increased to the first speed; if the maximum temperature value is less than or equal to the second tolerance temperature threshold of the battery pack, the opening of the electronic expansion valve is reduced to the second opening, and the speed of the compressor is reduced to the second speed, wherein the first tolerance temperature threshold is greater than the second tolerance temperature threshold; at the maximum temperature When the difference between the maximum temperature value and the minimum temperature value is less than or equal to the design threshold and greater than 0, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold, the stop valve and the first water pump are opened, and at the same time, the opening of the electronic expansion valve is increased to the third opening, and the speed of the compressor is increased to the third speed; if the maximum temperature value is less than or equal to the second tolerance temperature threshold, the stop valve is closed, the opening of the electronic expansion valve is reduced to the fourth opening, and the speed of the compressor is reduced to the fourth speed; wherein the first opening, the second opening, the third opening and the fourth opening are reduced in sequence; and the first speed, the second speed, the third speed and the fourth speed are reduced in sequence.

[0012] Furthermore, the condenser is an air-cooled condenser, and the passenger compartment thermal management circuit also includes a first fan arranged adjacent to the condenser; the temperature control method also includes: when increasing or decreasing the speed of the compressor, simultaneously increasing or decreasing the speed of the first fan.

[0013] Furthermore, the condenser is a water-cooled condenser, and the passenger compartment thermal management circuit also includes a second water pump connected to the condenser, a radiator, and a second fan arranged adjacent to the radiator; the temperature control method also includes: when increasing or decreasing the speed of the compressor, simultaneously increasing or decreasing the speed of the second fan.

[0014] In the second aspect, an embodiment of the present application provides a temperature control device for a battery pack, which is applied to a passenger compartment thermal management circuit and a battery pack thermal management circuit arranged in parallel. The passenger compartment thermal management circuit includes a main line and a first branch and a second branch connected to the main line and in parallel. The main line includes a compressor, a condenser, and a liquid reservoir arranged in sequence. The first branch includes an evaporator and an electronic expansion valve connected to the inlet of the evaporator. The second branch includes a cooler, a thermal expansion valve connected to the inlet of the cooler, and a stop valve connected to the thermal expansion valve; the battery pack thermal management circuit includes a battery pack, a first water pump, and a cooler arranged in sequence. The side of the cooler facing the evaporator is a refrigerant, and the cooler facing One side of the battery pack is coolant, and multiple temperature sensors are provided in the battery pack for detecting the temperature of various positions in the battery pack; the temperature control device includes: an acquisition unit, configured to obtain the maximum temperature value and the minimum temperature value in the battery pack; a comparison unit, configured to compare whether the difference between the maximum temperature value and the minimum temperature value is greater than the design threshold, and whether the maximum temperature value is greater than or equal to the first tolerance temperature threshold of the battery pack, and output the comparison result; a control unit, configured to start the compressor, the first water pump and the shut-off valve if the comparison result is yes, so that the first water pump drives the coolant into the battery pack, and exchanges the heat generated by the battery pack with the refrigerant in the cooler.

[0015] Furthermore, the comparison unit is further configured to compare whether the maximum temperature value is less than or equal to the second tolerance temperature threshold of the battery pack and output the comparison result; the control unit is further configured to close the shut-off valve and reduce the speed of the compressor if the comparison result is yes, wherein the first tolerance temperature threshold is greater than the second tolerance temperature threshold.

[0016] Furthermore, the comparison unit is further configured to compare whether the difference between the maximum temperature value and the minimum temperature value is less than or equal to the design threshold and greater than 0; the control unit is further configured to, if the comparison result is yes, turn off the first water pump.

[0017] Furthermore, the acquisition unit is further configured to obtain the minimum temperature value in the battery pack; the control unit is further configured to close the shut-off valve if the difference between the maximum temperature value and the minimum temperature value is less than or equal to the design threshold, and the maximum temperature value is less than the first tolerance temperature threshold of the battery pack and greater than the second tolerance temperature threshold, wherein the first tolerance temperature threshold is greater than the second tolerance temperature threshold.

[0018] Furthermore, the control unit is further configured to turn off the first water pump if the maximum temperature value is less than or equal to a second tolerance temperature threshold.

[0019] Furthermore, the acquisition unit is further configured to obtain a temperature value of the passenger compartment; the control unit is further configured to, if the temperature value of the passenger compartment is greater than a target threshold, turn on the electronic expansion valve and the compressor to cool the passenger compartment, and adjust the opening of the electronic expansion valve and the speed of the compressor according to the temperature change of the battery pack.

[0020] Furthermore, when the comparison result of the comparison unit is that the difference between the maximum temperature value and the minimum temperature value of the battery pack is greater than the design threshold, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold of the battery pack, the control unit is further configured to increase the opening of the electronic expansion valve to the first opening and increase the speed of the compressor to the first speed; if the maximum temperature value is less than or equal to the second tolerance temperature threshold of the battery pack, the control unit is further configured to reduce the opening of the electronic expansion valve to the second opening and reduce the speed of the compressor to the second speed, wherein the first tolerance temperature threshold is greater than the second tolerance temperature threshold; the comparison result of the comparison unit is that the difference between the maximum temperature value and the minimum temperature value is less than When the maximum temperature value is greater than or equal to the design threshold and greater than 0, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold, the control unit is further configured to open the stop valve and the first water pump, and at the same time increase the opening of the electronic expansion valve to a third opening, and increase the speed of the compressor to a third speed; if the maximum temperature value is less than or equal to the second tolerance temperature threshold, the control unit is further configured to close the stop valve, reduce the opening of the electronic expansion valve to a fourth opening, and reduce the speed of the compressor to a fourth speed. The opening of the electronic expansion valve and the speed of the compressor are reduced; wherein the first opening, the second opening, the third opening and the fourth opening are reduced in sequence; the first speed, the second speed, the third speed and the fourth speed are reduced in sequence.

[0021] Furthermore, the condenser is an air-cooled condenser, and the passenger compartment thermal management circuit also includes a first fan arranged adjacent to the condenser; the control unit is further configured to increase or decrease the speed of the first fan at the same time when increasing or decreasing the speed of the compressor.

[0022] Furthermore, the condenser is a water-cooled condenser, and the passenger compartment thermal management circuit also includes a second water pump connected to the condenser, a radiator, and a second fan arranged adjacent to the radiator; the control unit is further configured to increase or decrease the speed of the second fan at the same time when increasing or decreasing the speed of the compressor.

[0023] In a third aspect, an embodiment of the present application provides a temperature control device for a battery pack, comprising: a memory storing computer program instructions; and a processor, which implements the temperature control method for the battery pack as described above when the computer program instructions are executed by the processor.

[0024] In a fourth aspect, an embodiment of the present application provides a new energy vehicle, comprising a passenger compartment thermal management circuit and a battery pack thermal management circuit arranged in parallel, and a temperature control device of the battery pack as described above, wherein the temperature control device is electrically connected to the passenger compartment thermal management circuit and the battery pack thermal management circuit respectively.

[0025] In a fifth aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method described in the first aspect or any one of the above methods.

[0026] In a sixth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the method as described in the first aspect or any one of the methods above. The temperature control method, device, equipment and new energy vehicle of the battery pack provided in accordance with the embodiments of the present application are applied to a passenger compartment thermal management circuit and a battery pack thermal management circuit arranged in parallel, the passenger compartment thermal management circuit including a main road and a first branch and a second branch connected to the main road and in parallel, the main road including a compressor, a condenser and a liquid reservoir arranged in sequence, the first branch including an evaporator and an electronic expansion valve connected to the inlet of the evaporator, the second branch including a cooler, a thermal expansion valve connected to the inlet of the cooler and a stop valve connected to the thermal expansion valve; the battery pack thermal management circuit includes a battery pack, a first water pump and a cooler arranged in sequence, the side of the cooler facing the evaporator is Refrigerant, the side of the cooler facing the battery pack is coolant, and multiple temperature sensors are provided in the battery pack to detect the temperature of various positions in the battery pack; thus, by sharing the same cooler in the passenger compartment thermal management circuit and the battery pack thermal management circuit, and the side of the cooler facing the evaporator is coolant, and the side of the cooler facing the battery pack is refrigerant, and a combination valve group of a thermal expansion valve and a shut-off valve is provided at the inlet of the cooler, the on and off of the shut-off valve can be controlled according to the temperature difference inside the battery pack, and the flow of the refrigerant can be actively adjusted to achieve fine control of the temperature inside the battery pack, avoid thermal runaway of the battery pack due to uneven discharge, and improve the service life of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a schematic diagram showing the structure of a passenger compartment thermal management circuit and a battery pack thermal management circuit in a new energy vehicle provided by an embodiment of the present application;

[0028] FIG2 is a schematic structural diagram of a passenger compartment thermal management circuit and a battery pack thermal management circuit in another new energy vehicle provided by an embodiment of the present application;

[0029] FIG3 is a flow chart showing a temperature control method for a battery pack according to an embodiment of the present application;

[0030] FIG4 shows a schematic structural diagram of a temperature control device for a battery pack provided in an embodiment of the present application.

[0031] Among them, M1-passenger compartment thermal management circuit; M2-battery pack thermal management circuit; L-main line; B1-first branch; B2-second branch; 1-compressor; 2-condenser; 21-first fan; 22-second fan; 23-second water pump; 24-radiator; 3-liquid reservoir; 4-evaporator; 5-electronic expansion valve; 6-cooler; 7-thermal expansion valve; 8-stop valve; 9-first water pump; 10-battery pack;

[0032] Tmax-maximum temperature value; Tmin-minimum temperature value; T1-design threshold; Tba1-first tolerance temperature threshold; Tba2-second tolerance temperature threshold; T2-target threshold;

[0033] 100 - acquisition unit; 200 - comparison unit; 300 - control unit. DETAILED DESCRIPTION

[0034] The following will describe the embodiments of the present application with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand the other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for the purpose of illustrating the present application and are not intended to limit the scope of protection of the present application.

[0035] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. Therefore, the illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0036] As shown in Figures 1 and 2, an embodiment of the present application provides a new energy vehicle, including a passenger compartment thermal management circuit M1 and a battery pack thermal management circuit M2 arranged in parallel. The passenger compartment thermal management circuit M1 includes a main line L and a first branch B1 and a second branch B2 connected to the main line L and in parallel. The main line L includes a compressor 1, a condenser 2, and a liquid reservoir 3 arranged in sequence. The first branch B1 includes an evaporator 4 and an electronic expansion valve 5 connected to the inlet of the evaporator 4. The second branch B2 includes a cooler 6, a thermal expansion valve 7 connected to the inlet of the cooler 6, and a stop valve 8 connected to the thermal expansion valve 7.

[0037] The main trunk L of the passenger compartment thermal management loop M1 includes a compressor 1, a condenser 2, and a liquid reservoir 3, which are arranged in sequence. As shown in Figure 1, the condenser 2 can be an air-cooled condenser 2. The passenger compartment thermal management loop M1 also includes a first fan 21 disposed adjacent to the condenser 2. As shown in Figure 2, the condenser 2 is a water-cooled condenser 2. The passenger compartment thermal management loop M1 also includes a second water pump 23 connected to the condenser 2, a radiator 24, and a second fan 22 disposed adjacent to the radiator 24.

[0038] First branch B1 includes an evaporator 4 and an electronic expansion valve 5 connected to the inlet of evaporator 4. Evaporator 4 is a core component of the heating, ventilation, and air conditioning (HVAC) system. Heat is exchanged between evaporator 4 and the driver's cabin via the HVAC's air supply equipment. When electronic expansion valve 5 is open, first branch B1 is connected, and refrigerant flows through evaporator 4 and condenser 2 under the action of compressor 1, achieving cooling control of the passenger compartment. When electronic expansion valve 5 is closed, first branch B1 is disconnected, and cooling control of the passenger compartment is no longer provided.

[0039] The second branch B2 includes a cooler 6, a thermal expansion valve 7 connected to the inlet of the cooler 6, and a stop valve 8 connected to the thermal expansion valve 7. The side of the cooler 6 facing the evaporator 4 is a refrigerant, and the side of the cooler 6 facing the battery pack 10 is a coolant. The thermal expansion valve 7 can be a temperature control valve, and its working principle is to passively adjust the refrigerant flow in the cooler 6 by sensing the degree of superheat of the refrigerant flowing through, and to achieve on-off control through the stop valve 8. When the stop valve 8 is opened, the second branch B2 is connected, and the passenger compartment thermal management circuit M1 can be used to actively adjust the refrigerant flow in the cooler 6, wherein the refrigerant can be tetrafluoroethane refrigerant (such as R134a) or a mixed refrigerant (such as R410a), etc., but is not limited to this.

[0040] The battery pack thermal management circuit M2 includes a battery pack 10, a first water pump 9, and a cooler 6, which are arranged in sequence. Multiple temperature sensors are installed within the battery pack 10 to detect the temperature at various locations within the battery pack 10. When the first water pump 9 is turned on, it drives the coolant through the battery pack 10, removing the heat generated by the battery pack 10, thereby achieving cooling control of the battery pack 10. If the shut-off valve 8 is also opened, the coolant can exchange heat with the refrigerant as it flows through the cooler 6. The evaporation of the refrigerant removes the heat from the coolant, improving cooling efficiency.

[0041] Furthermore, the components within the passenger compartment thermal management circuit M1 and the battery pack thermal management circuit M2 are connected by pipes. These pipes can be metal pipes, such as copper or aluminum alloy pipes, or rubber or plastic pipes, without limitation. The pipes between components can be made of the same material, or the material can be appropriately selected based on the temperature of the coolant in each pipe during operation, without limitation.

[0042] As shown in Figure 3, an embodiment of the present application provides a battery pack temperature control method, which is applied to the passenger compartment thermal management circuit M1 and the battery pack thermal management circuit M2 arranged in parallel as described above. The temperature control method includes the following steps S1 to S3. The specific steps of the battery pack temperature control method are described in detail below in conjunction with Figures 1 and 2.

[0043] Step S1: Obtain the maximum temperature value and the minimum temperature value in the battery pack.

[0044] The maximum temperature value Tmax and the minimum temperature value Tmin within the battery pack 10 can be screened from a set of data measured by multiple temperature sensors installed within the battery pack 10. For example, the maximum temperature value Tmax is located at the electrode terminals of the battery pack, and the minimum temperature value Tmin is located at the position of the battery pack casing farthest from the electrode terminals. The maximum temperature value Tmax and the minimum temperature value Tmin at different times within the battery pack 10 can be located at the same or different locations.

[0045] Step S2 : comparing whether the difference between the maximum temperature value and the minimum temperature value is greater than a design threshold, and whether the maximum temperature value is greater than or equal to a first tolerance temperature threshold of the battery pack 10 .

[0046] The design threshold T1 is the temperature difference allowed for the battery pack 10 in the working state, and the value range of T1 is 5°C to 10°C. In one example, T1 = 6°C. The first tolerance temperature threshold Tba1 is the tolerance temperature value at which the battery pack 10 does not experience thermal runaway in the working state. Optionally, the value range of Tba1 is 43°C to 50°C. In one example, Tba1 = 45°C. The design threshold T1 and the first tolerance temperature threshold Tba1 can be determined according to the specific application environment of the actual product, and are not limited to the examples.

[0047] Step S3: If yes, turn on the compressor 1 , the first water pump 9 and the shut-off valve 8 so that the first water pump 9 drives the coolant into the battery pack 10 and exchanges the heat generated by the battery pack 10 with the refrigerant in the cooler 6 .

[0048] If Tmax-Tmin≥T1, and Tmax≥Tba1, it indicates that the temperature difference within the battery pack 10 is large, and the maximum temperature is about to enter a thermal runaway state, requiring the battery pack 10 to be cooled as soon as possible. At this time, in addition to starting the first water pump 9 in the battery pack thermal management circuit M2 to drive coolant into the battery pack 10 to remove heat from the battery pack 10, the shut-off valve 8 and compressor 1 can also be opened, and the second branch L2 in the passenger compartment thermal management circuit M1 can be started to circulate the refrigerant in the passenger compartment thermal management circuit M1. The refrigerant flow rate is actively adjusted to improve the heat exchange efficiency between the refrigerant and the coolant in the cooler 6, further improving the cooling efficiency of the battery pack 10.

[0049] Therefore, the temperature control method of the battery pack provided in the embodiment of the present application shares the same cooler 6 in the passenger compartment thermal management circuit M1 and the battery pack thermal management circuit M2, and the side of the cooler 6 facing the evaporator 4 is the refrigerant, and the side of the cooler 6 facing the battery pack 10 is the coolant, and a combined valve group of a thermal expansion valve 7 and a stop valve 8 is provided on one side of the cooler 6. The on and off of the stop valve 8 can be controlled according to the temperature difference inside the battery pack 10, and the flow rate of the refrigerant can be actively adjusted to achieve fine control of the internal temperature of the battery pack 10, avoid thermal runaway of the battery pack 10 due to uneven discharge, and improve the safety and reliability of the battery pack 10.

[0050] In some embodiments, the temperature control method of the battery pack further includes:

[0051] Step S4: comparing whether the maximum temperature value is less than or equal to a second tolerance temperature threshold of the battery pack 10;

[0052] Step S5: If yes, close the stop valve 8 and reduce the rotation speed of the compressor 1, wherein the first tolerance temperature threshold Tbat1 is greater than the second tolerance temperature threshold Tbat2.

[0053] Optionally, the value range of Tba2 is 41° C. to 50° C.; further optionally, Tba1-Tba2=2° C. to 5° C. In one example, the second temperature tolerance threshold Tba2=43° C.

[0054] When Tmax≤Tbat2, the battery pack 10 gradually drops from the state of impending thermal runaway to Tbat1 and Tbat2, and then the battery pack 10 leaves the thermal runaway state. The shut-off valve 8 can be closed to disconnect the second branch B2 of the passenger compartment thermal management loop M1, and the speed of the compressor 1 can be reduced, even to 0, so as to reduce the flow of the refrigerant. The coolant can be driven into the battery pack 10 by the first water pump 9 of the battery pack thermal management loop M2 itself to dissipate heat until the average temperature of the battery pack 10 drops to a safe operating temperature range, thereby ensuring uniform discharge of the battery pack 10 while greatly reducing energy consumption.

[0055] In some embodiments, the temperature control method of the battery pack further includes:

[0056] Step S5: Compare whether the difference between the maximum temperature value and the minimum temperature value is less than or equal to the design threshold and greater than 0;

[0057] Step S6: If so, turn off the first water pump 9.

[0058] When 0 < Tmax - Tmin ≤ T1, it indicates that the internal temperature difference of the battery pack 10 is small and within the safe operating temperature range, and there is no need to continue cooling. Just turn off the first water pump 9 to reduce energy waste and lower energy consumption.

[0059] In some embodiments, when both the battery pack 10 and the passenger compartment have a cooling requirement, in order to improve the comfort of the passenger compartment, the temperature control method of the battery pack further includes:

[0060] Step S1': Obtain the temperature value of the passenger compartment;

[0061] Step S2': If the temperature value of the passenger compartment is greater than the target threshold, turn on the electronic expansion valve 5 and the compressor 1 to cool the passenger compartment, and adjust the opening degree of the electronic expansion valve 5 and the rotation speed of the compressor 1 according to the temperature change of the battery pack 10.

[0062] The target threshold T2 of the passenger compartment is generally 27°C to 30°C. If the temperature value of the passenger compartment is greater than the target threshold T2, it is necessary to turn on the electronic expansion valve � to connect the main road L and the first branch L1 of the passenger compartment thermal management circuit M1, and cool the passenger compartment through the combined action of the compressor 1, the condenser 2 and the evaporator 4. At the same time, the opening degree of the electronic expansion valve 5 and the rotation speed of the compressor 1 can also be adjusted according to the temperature change of the battery pack 10 to change the refrigerant flow rate, and then adjust the cooling effect of the battery pack 10 to minimize energy waste and reduce energy consumption as much as possible.

[0063] Specifically, in step S2', adjusting the opening degree of the electronic expansion valve 5 and the rotation speed of the compressor 1 according to the temperature change of the battery pack 10 includes:

[0064] Step S21: When the difference between the maximum temperature value and the minimum temperature value of the battery pack 10 is greater than the design threshold, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold of the battery pack 10, increase the opening degree of the electronic expansion valve 5 to the first opening degree and increase the rotation speed of the compressor I to the first rotation speed;

[0065] If the maximum temperature value is less than the second tolerance temperature threshold of the battery pack 10, reduce the opening degree of the electronic expansion valve 5 to the second opening degree and reduce the rotation speed of the compressor 1 to the second rotation speed, where the first tolerance temperature threshold is greater than the second tolerance temperature threshold.

[0066] Step S22: When the difference between the maximum temperature value and the minimum temperature value is less than or equal to the design threshold and greater than 0, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold, the stop valve 8 and the first water pump 9 are opened, and at the same time, the opening of the electronic expansion valve 5 is increased to a third opening, and the speed of the compressor 1 is increased to a third speed;

[0067] If the maximum temperature value is less than the second tolerance temperature threshold, the stop valve 8 is closed, the opening of the electronic expansion valve 5 is reduced to a fourth opening, and the speed of the compressor 1 is reduced to a fourth speed;

[0068] The first opening, the second opening, the third opening and the fourth opening decrease in sequence; the first rotational speed, the second rotational speed, the third rotational speed and the fourth rotational speed decrease in sequence.

[0069] Assuming that under normal working conditions, only the passenger compartment has a cooling demand, the opening of the electronic expansion valve 5 is the fourth opening, which can be, for example, 40% to 50% of the maximum opening; the speed of the compressor 1 is the fourth speed, which can be, for example, 60% of the maximum speed.

[0070] When the passenger compartment has a cooling demand and the temperature difference of the battery pack 10 is large and is in a state of imminent thermal runaway (Tmax-Tmin≥T1, and Tmax≥Tba1), the opening of the electronic expansion valve 5 can be increased to a first opening, which can be, for example, 80% to 100% of the maximum opening, and the speed of the compressor 1 can be increased to a first speed, which can be, for example, 80% to 100% of the maximum speed. This can actively increase the opening of the temperature control valve 7, thereby increasing the refrigerant flow in the cooler 6, improving the heat exchange efficiency between the coolant and the refrigerant of the battery pack 10, and achieving simultaneous cooling of the passenger compartment and the battery pack 10.

[0071] When the battery pack 10 is out of the thermal runaway state (Tmax≤Tbat2), the opening of the electronic expansion valve 5 can be reduced to a second opening, which can be, for example, 60% to 80% of the maximum opening, and the speed of the compressor 1 can be reduced to a second speed, which can be, for example, 60% to 80% of the maximum speed, thereby reducing the heat exchange efficiency of the cooler 6. Only the first water pump 9 is used to drive the coolant flowing through the inside of the battery pack 10 to exchange heat with the refrigerant, thereby reducing energy waste and energy consumption.

[0072] When the occupant compartment has a cooling requirement, the internal temperature difference of the battery pack 10 is small, and the maximum temperature value is large (0 < Tmax - Tmin ≤ T1, and Tmax ≥ Tba1), it is necessary to quickly cool the local high-temperature area of the battery pack 10. At this time, the cut-off valve 8 and the first water pump 9 are opened, and at the same time, the opening degree of the electronic expansion valve 5 is increased to the third opening degree. The third opening degree can be, for example, 50% - 60% of the maximum opening degree, and the rotational speed of the compressor 1 is increased to the third rotational speed. The third rotational speed can be, for example, 50% - 60% of the maximum rotational speed, so as to actively increase the opening degree of the temperature control valve 7, and then increase the refrigerant flow rate in the cooler 6, and further improve the heat exchange efficiency between the coolant of the battery pack 10 and the refrigerant, realizing the simultaneous cooling of the occupant compartment and the battery pack 10.

[0073] When the battery pack 10 gets out of the thermal runaway state (Tmax ≤ Tbat2) and reaches the safe operating temperature range, the cut-off valve 8 can be closed at this time. Only by driving the coolant to flow through the inside of the battery pack 10 through the first water pump 9 to take away heat can the cooling requirement of the battery pack be met. At the same time, the opening degree of the electronic expansion valve 5 and the rotational speed of the compressor 1 are adjusted to the normal operating state, that is, the opening degree of the electronic expansion valve 5 is reduced to the fourth opening degree. The fourth opening degree can be, for example, 40% - 50% of the maximum opening degree, and the rotational speed of the compressor 1 is reduced to the fourth rotational speed. The fourth rotational speed can be, for example, 60% of the maximum rotational speed. Only cooling the occupant compartment can reduce energy waste and energy consumption.

[0074] In some embodiments, as shown in FIG. 1, the condenser 2 is an air-cooled condenser 2, and the occupant compartment thermal management circuit M1 further includes a first fan 21 disposed adjacent to the condenser 2. The temperature control method for the battery pack further includes: when increasing or decreasing the rotational speed of the compressor 1, simultaneously increasing or decreasing the rotational speed of the first fan 21. The magnitude of the rotational speed of the first fan 21 depends on the specific application environment. The first fan 21 can accelerate or reduce the air flow, change the cooling effect of the refrigerant in the condenser 2 and the evaporator 4, and then actively adjust the opening degree of the temperature control valve 7, increase the refrigerant flow rate in the cooler 6, and further improve the heat exchange efficiency between the coolant of the battery pack 10 and the refrigerant.

[0075] In some embodiments, as shown in FIG2 , the condenser 2 is a water-cooled condenser 2 , and the passenger compartment thermal management circuit M1 further includes a second water pump 23 connected to the condenser 2 , a radiator 24 , and a second fan 22 disposed adjacent to the radiator 24 . The temperature control method further includes: when the speed of the compressor 1 is increased or decreased, the speed of the second fan 22 is simultaneously increased or decreased. The speed of the second fan 22 is determined according to the specific application environment. The second fan 22 can accelerate or decrease air flow, change the cooling effect of the refrigerant in the condenser 2 and evaporator 4 , and then actively adjust the opening of the temperature control valve 7 , increase the refrigerant flow in the cooler 6 , and further improve the heat exchange efficiency between the coolant and the refrigerant in the battery pack 10 .

[0076] As shown in Figure 4, an embodiment of the present application also provides a temperature control device for a battery pack, which is applied to the passenger compartment thermal management loop M1 and the battery pack 10 thermal management loop M2 arranged in parallel as described above. The temperature control device includes: an acquisition unit 100, a comparison unit 200 and a control unit 300.

[0077] The acquisition unit 100 is configured to acquire a maximum temperature value and a minimum temperature value within the battery pack 10;

[0078] The comparison unit 200 is configured to compare whether the difference between the maximum temperature value and the minimum temperature value is greater than a design threshold, and whether the maximum temperature value is greater than or equal to a first tolerance temperature threshold of the battery pack 10 , and output a comparison result.

[0079] The control unit 300 is configured to, if the comparison result is yes, turn on the compressor 1, the first water pump 9 and the shut-off valve 8, so that the first water pump 9 drives the coolant into the battery pack 10 and exchanges the heat generated by the battery pack 10 with the refrigerant in the cooler 6.

[0080] Therefore, the temperature control device of the battery pack provided in the embodiment of the present application shares the same cooler 6 in the passenger compartment thermal management circuit M1 and the battery pack thermal management circuit M2, and the side of the cooler 6 facing the evaporator 4 is the refrigerant, and the side of the cooler 6 facing the battery pack 10 is the coolant, and a combined valve group of a thermal expansion valve 7 and a stop valve 8 is provided on one side of the cooler 6. The on and off of the stop valve 8 can be controlled according to the temperature difference inside the battery pack 10, and the flow rate of the refrigerant can be actively adjusted to achieve fine control of the internal temperature of the battery pack 10, avoid thermal runaway of the battery pack 10 due to uneven discharge, and improve the safety and reliability of the battery pack 10.

[0081] In some embodiments, the comparison unit 200 is further configured to compare whether the maximum temperature value is less than or equal to the second tolerance temperature threshold of the battery pack 10 and output the comparison result; the control unit 300 is further configured to close the shut-off valve 8 and reduce the speed of the compressor 1 if the comparison result is yes, wherein the first tolerance temperature threshold is greater than the second tolerance temperature threshold.

[0082] In some embodiments, the comparison unit 200 is further configured to compare whether the difference between the maximum temperature value and the minimum temperature value is greater than 0 and less than or equal to the design threshold; the control unit is further configured to turn off the first water pump 9 if the comparison result is yes.

[0083] In some embodiments, the acquisition unit 100 is further configured to obtain the temperature value of the passenger compartment; the control unit 300 is further configured to, if the temperature value of the passenger compartment is greater than the target threshold, open the electronic expansion valve 5 and the compressor 1 to cool the passenger compartment, and adjust the opening of the electronic expansion valve 5 and the speed of the compressor 1 according to the temperature change of the battery pack 10.

[0084] In some embodiments, when the comparison result of the comparison unit 200 is that the difference between the maximum temperature value and the minimum temperature value of the battery pack 10 is greater than the design threshold, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold of the battery pack 10, the control unit 300 is further configured to increase the opening of the electronic expansion valve 5 to a first opening, and increase the speed of the compressor 1 to a first speed; if the maximum temperature value is less than or equal to the second tolerance temperature threshold of the battery pack 10, the control unit 300 is further configured to reduce the opening of the electronic expansion valve 5 to a second opening, and reduce the speed of the compressor 1 to a second speed, wherein the first tolerance temperature threshold is greater than the second tolerance temperature threshold.

[0085] Furthermore, when the comparison result of the comparison unit 200 is that the difference between the maximum temperature value and the minimum temperature value is less than or equal to the design threshold and greater than 0, if the maximum temperature value is greater than or equal to the first tolerance temperature threshold, the control unit 300 is further configured to open the stop valve 8 and the first water pump 9, and at the same time increase the opening of the electronic expansion valve 5 to the third opening, and increase the speed of the compressor 1 to the third speed; if the maximum temperature value is less than or equal to the second tolerance temperature threshold, the control unit 300 is further configured to close the stop valve 8, reduce the opening of the electronic expansion valve 5 to the fourth opening, and reduce the speed of the compressor 1 to the fourth speed.

[0086] In some embodiments, the condenser 2 is an air-cooled condenser 2, and the passenger compartment thermal management circuit M1 also includes a first fan 21 arranged adjacent to the condenser 2; the control unit is further configured to increase or decrease the speed of the first fan 21 at the same time when increasing or decreasing the speed of the compressor 1.

[0087] In some embodiments, the condenser 2 is a water-cooled condenser 2, and the passenger compartment thermal management circuit M1 also includes a second water pump 23 connected to the condenser 2, a radiator 24, and a second fan 22 arranged adjacent to the radiator 24; the control unit is further configured to increase or decrease the speed of the second fan 22 at the same time when increasing or decreasing the speed of the compressor 1.

[0088] It can be understood that the temperature control device of the battery pack provided in the embodiment of the present application is the executor of the aforementioned temperature control method of the battery pack. For the specific execution methods and beneficial effects of each unit, please refer to the contents of the aforementioned temperature control method of the battery pack, which will not be repeated here.

[0089] In addition, an embodiment of the present application provides a temperature control device for a battery pack, including:

[0090] a memory storing computer program instructions;

[0091] The processor implements the temperature control method of the battery pack as described above when the computer program instructions are executed by the processor.

[0092] The temperature control device is electrically connected to the passenger compartment thermal management circuit M1 and the battery pack thermal management circuit M2 respectively. It can be integrated into the passenger compartment thermal management circuit M1, the battery pack thermal management circuit M2, or be set separately, which will not be repeated here.

[0093] In addition, an embodiment of the present application provides a new energy vehicle, including a passenger compartment thermal management circuit M1 and a battery pack 10 thermal management circuit M2 arranged in parallel, and a temperature control device of the battery pack as described above, and the temperature control device is electrically connected to the passenger compartment thermal management circuit M1 and the battery pack 10 thermal management circuit M2 respectively.

[0094] In addition, the present application provides a computer-readable storage medium, which stores computer execution instructions. When the computer execution instructions are executed by a processor, they are used to implement any of the above-mentioned method embodiments. The specific implementation methods and technical effects are similar and will not be repeated here.

[0095] The present application provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements any one of the above method embodiments. The specific implementation methods and technical effects are similar and will not be repeated here.

[0096] The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. Such program code can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable interrupt handling device, so that when the program code is executed by the processor or controller, the functions / operations specified in the flow chart and / or block diagram are implemented. The program code can be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0097] In the context of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of machine-readable storage media may include an electrical connection based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. It should be noted that references in the specification to "one embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether explicitly or not explicitly described.

[0098] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

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