Thermal management control strategy analysis method for liquid-cooled battery of new energy automobile

Abstract

The invention discloses a new energy automobile liquid cooling battery thermal management control strategy analysis method, which has the main conception that an external temperature control device is connected to a whole automobile battery cooling loop; activating a battery management system when a charging gun connected with the direct current charging pile is in a non-charging state; temperature control parameters of an external temperature control device are set according to the set temperature test area, and temperature control is started; when the actually measured temperature of the water inlet and the water outlet of the battery pack and the battery temperature output by the charging pile meet the set standard, the temperature control parameters are changed according to the preset gradient, and temperature control and standard judgment are executed again; executing temperature control of all the temperature control parameters in the temperature test area room, and recording the control duration under each temperature control parameter and the temperature difference between the water inlet and the water outlet; and thermal management strategy analysis is started, and the advantages and disadvantages of thermal management system control of the battery liquid cooling system are analyzed, so that the thermal management comfort and thermal management energy consumption of the new energy automobile are improved, and the cruising ability of the whole automobile is further improved.

Description

Technical Field

[0001] The present invention relates to the field of thermal management tests for new energy vehicles, and in particular to a method for analyzing a thermal management control strategy for a liquid-cooled battery in a new energy vehicle. Background Art

[0002] The development of new energy vehicles has brought new challenges and requirements to thermal management. Its thermal management system has gradually developed from a single engine cooling and air conditioning system to an integrated and intelligent one. With the help of advanced sensor technology, intelligent control algorithms and Internet of Vehicles technology, it can sense the vehicle's status, external ambient temperature, component internal temperature, driver and passenger comfort requirements, and expected road conditions in real time, and automatically adjust the thermal management strategy based on this information, combining the thermal management of components such as batteries, motors, and electronic controls with the air conditioning system, achieving comprehensive utilization and coordinated control of heat, and focusing on cabin comfort and vehicle energy consumption while meeting the vehicle's thermal management performance.

[0003] Taking the battery liquid cooling temperature control management system as an example, the electric coolant pump drives the coolant to circulate in the battery pack to maintain the ideal temperature. The main components of its temperature control management system include electric water pump, battery cell cooling circuit, temperature sensor, air conditioning system (compressor, condenser, evaporator), heater and liquid-liquid heat exchanger. These components work together to achieve precise control of battery temperature. Different models have different control strategies. In order to compare the advantages and disadvantages of the thermal management control logic of different models, it is necessary to gradually analyze the thermal management control strategy of the vehicle in order to smoothly carry out comparative analysis.

[0004] However, at present, there is no effective thermal management control strategy analysis solution for liquid-cooled battery systems in the industry. Summary of the invention

[0005] In view of the above, the present invention aims to provide a method for analyzing the thermal management control strategy of a liquid-cooled battery of a new energy vehicle, so as to analyze the thermal management control strategy of the vehicle, facilitate a clear analysis of the advantages and disadvantages of different control modes, and thus improve the thermal management comfort and energy consumption of the new energy vehicle.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for analyzing a thermal management control strategy of a liquid-cooled battery of a new energy vehicle, which includes:

[0008] Connect the external temperature control device to the vehicle battery cooling circuit;

[0009] When the vehicle is connected to the charging gun of the DC charging pile and is in a non-charging state, activate the battery management system;

[0010] According to the established temperature test interval, starting from the endpoint temperature of the interval, set the temperature control parameters of the external temperature control device and start the temperature control;

[0011] When the measured temperatures of the water inlet and outlet of the battery pack and the battery temperature value output by the charging pile meet the established standards, the temperature control parameters are changed according to the preset gradient and the temperature control and compliance determination are performed again;

[0012] Perform temperature control of all temperature control parameters within the temperature test interval in the above manner, and record the control time under each temperature control parameter and the temperature difference between the water inlet and the water outlet;

[0013] Start thermal management strategy analysis:

[0014] Setting the vehicle status and the initial setting value of the external temperature control device;

[0015] If the current temperature difference between the battery water inlet and outlet and the current control time are measured to meet the established requirements, the temperature is raised and lowered step by step, and the inlet and outlet temperatures of the battery pack, battery pack cooler, liquid-liquid heat exchanger, and the operating parameters of the air-conditioning compressor, battery water pump, and PTC are recorded respectively;

[0016] During the heating process or the cooling process, the inlet and outlet temperatures and the operating parameters are used to analyze key information of the thermal management strategy, and the key information includes at least any one of the following: a temperature threshold for starting battery cooling, a battery cooling requirement level, a temperature threshold for downgrading or exiting the battery cooling requirement, a temperature threshold for starting battery heating, and a temperature threshold for downgrading or exiting the battery heating requirement.

[0017] In at least one possible implementation, after meeting the established requirements, the step-by-step temperature increase and temperature decrease control includes: when the current temperature difference is consistent with the temperature difference at the corresponding temperature previously recorded, and the current control time is not less than the control time previously recorded, the temperature is increased or decreased according to the established step length.

[0018] In at least one possible implementation, the thermal management strategy analysis includes: high temperature thermal management strategy analysis;

[0019] During the temperature rise process of the high-temperature thermal management strategy analysis, when the average value of the battery inlet and outlet water temperatures is at the current temperature point, if the compressor and water pump generate current signals and the inlet and outlet temperature difference of the cooler increases, the current temperature point is the start-up temperature threshold for battery cooling;

[0020] During the cooling process of the high-temperature thermal management strategy analysis, when the average temperature of the battery inlet and outlet water is at the current temperature point, if the current value of the compressor and water pump is reduced or exited, the current temperature point is the temperature threshold for the battery cooling demand to be degraded or exited.

[0021] In at least one possible implementation, during the high-temperature thermal management strategy analysis process, as the internal temperature of the battery increases, the battery cooling requirement level corresponding to the current temperature point is obtained through the compressor power and the water pump power.

[0022] In at least one possible implementation, the thermal management strategy analysis includes: low temperature thermal management strategy analysis;

[0023] During the heating process of the low-temperature thermal management strategy analysis, when the average value of the battery inlet and outlet water temperatures is at the current temperature point, if the PTC and water pump generate current signals and the inlet temperature of the liquid-liquid heat exchanger rises, the current temperature point is the start-up temperature threshold for battery heating.

[0024] In at least one possible implementation, during the low-temperature thermal management strategy analysis process, as the internal temperature of the battery increases, the temperature threshold for downgrading or exiting the battery heating demand corresponding to the current temperature point is obtained through the PTC power, water pump power, and the inlet temperature of the liquid-liquid heat exchanger.

[0025] In at least one possible implementation, the predetermined standard includes: a battery temperature value output by the charging pile is equal to an average value of actually measured temperatures at a water inlet and a water outlet.

[0026] In at least one possible implementation, the external temperature control device is connected to the liquid cooling water inlet and outlet of the battery pack, and specifically includes: a heating unit, a refrigeration unit and a temperature control unit.

[0027] Compared with the prior art, the main design concept of the present invention is to connect an external temperature control device to the battery cooling circuit of the whole vehicle; activate the battery management system when the whole vehicle is connected to the charging gun of the DC charging pile and is in a non-charging state; set the temperature control parameters of the external temperature control device and start temperature control according to a predetermined temperature test interval, starting from the endpoint temperature of the interval; when the measured temperatures of the water inlet and outlet of the battery pack and the battery temperature value output by the charging pile meet the established standards, change the temperature control parameters according to a preset gradient and perform temperature control and compliance judgment again; perform temperature control of all temperature control parameters within the temperature test interval in the above manner, and record the control time under each temperature control parameter and the temperature difference between the water inlet and the water outlet; start thermal management strategy analysis, through which the advantages and disadvantages of the thermal management system control of the battery liquid cooling system can be analyzed, thereby improving the thermal management comfort and thermal management energy consumption of new energy vehicles, and further improving the endurance of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0029] Figure 1 A schematic diagram of a method for analyzing a thermal management control strategy for a liquid-cooled battery in a new energy vehicle provided by an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of an external temperature control device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0032] The present invention proposes an embodiment of a method for analyzing a thermal management control strategy of a liquid-cooled battery in a new energy vehicle. Specifically, Figure 1 shown, including:

[0033] Step S1, connecting the external temperature control device to the vehicle battery cooling circuit;

[0034] Can be combined Figure 2 The schematic diagram of the external temperature control device connected to the battery pack at the vehicle end and used for liquid-cooled batteries is shown, which mainly includes: a heating unit, a refrigeration unit and a temperature control unit. Through the temperature regulation function of the external temperature control device in the test scenario of the present invention, it can ensure that the internal circulation flow of the battery thermal management circuit is small and the temperature control accuracy is high, thereby realizing convenient heating and cooling of the internal temperature of the battery to improve the test efficiency.

[0035] Step S2: When the vehicle is connected to the charging gun of the DC charging pile and is in a non-charging state, activate the battery management system (BMS).

[0036] Step S3, according to the established temperature test interval, starting from the endpoint temperature of the interval, setting the temperature control parameters of the external temperature control device and starting the temperature control;

[0037] Step S4: when the measured temperatures of the water inlet and outlet of the battery pack and the battery temperature value output by the charging pile meet the established standards, the temperature control parameters are changed according to the preset gradient and the temperature control and standard compliance determination are performed again;

[0038] Step S5, and so on, perform temperature control of all temperature control parameters within the temperature test interval, and record the control time under each temperature control parameter and the temperature difference between the water inlet and the water outlet;

[0039] The above process can be specifically described as, for example, setting the temperature test interval to -25°C~50°C, initially setting the temperature control parameter of the external temperature control device to -25°C, and using this set value to control the battery pack circuit temperature, while collecting the temperature of the battery inlet and outlet, the temperature difference, the battery temperature displayed by the charging pile, and the duration of control when the standard is met. In some preferred embodiments, when the battery temperature displayed on the charging pile end is equal to the average value of the battery inlet and outlet temperatures, adjust the set temperature of the external temperature control device to -24°C and continue to carry out the above test steps. By analogy, gradually increase the temperature to 50°C with a step size of 1°C, and record the control time and inlet and outlet temperature difference of each temperature setting point in the process; through the above steps, it can be analyzed that when the control time and the inlet and outlet temperature difference meet a certain range, the average value of the battery inlet and outlet water temperature will be approximately close to the internal temperature of the battery, which can be used to replace the internal temperature of the battery.

[0040] Step S6: Start thermal management strategy analysis:

[0041] Setting the vehicle status and the initial setting value of the external temperature control device;

[0042] If the current temperature difference between the battery water inlet and outlet and the current control time are measured to meet the established requirements, the temperature is raised and lowered step by step, and the inlet and outlet temperatures of the battery pack, battery pack cooler, liquid-liquid heat exchanger, and the operating parameters of the air-conditioning compressor, battery water pump, and PTC are recorded respectively;

[0043] During the heating process or the cooling process, the inlet and outlet temperatures and the operating parameters are used to analyze key information of the thermal management strategy, and the key information includes at least any one of the following: a temperature threshold for starting battery cooling, a battery cooling requirement level, a temperature threshold for downgrading or exiting the battery cooling requirement, a temperature threshold for starting battery heating, and a temperature threshold for downgrading or exiting the battery heating requirement.

[0044] The following is a detailed description of the strategy analysis for different thermal management scenarios of high temperature and low temperature.

[0045] 1. Analysis of high temperature thermal management strategy

[0046] 1) Set the vehicle to READY status and shift the gear to D. Set the external temperature control device's inspiration control temperature to 30°C. When the temperature difference between the battery inlet and outlet is consistent with the data at the corresponding temperature recorded in the previous step, and the control time of this temperature point is not less than the control time recorded in the previous step, increase the temperature to 31°C in steps of 1°C. And so on, gradually increase the temperature to 50°C (in line with the range set in the previous step), and then gradually cool down to the starting 30°C. During the process, at least record the compressor current and voltage, battery water pump current and voltage, battery inlet and outlet temperatures, battery pack cooler CHILLER inlet and outlet temperatures (refrigerant side), etc.;

[0047] 2) During the above-mentioned heating process, when the average temperature of the battery inlet and outlet water is at a certain temperature, the compressor and water pump generate current signals, and the temperature difference between the CHILLER inlet and outlet shows a significant increasing trend according to the preset quantitative threshold, then it can be determined that the current temperature point is the threshold for turning on battery cooling; and as the internal temperature of the battery increases, the battery cooling demand level at the corresponding current temperature can also be analyzed through the compressor power and water pump power;

[0048] 3) During the above cooling process, when the average temperature of the battery inlet and outlet water reaches a certain temperature, the current value of the compressor and water pump is significantly reduced (which can also be determined based on quantitative indicators) or exits. At this time, it can be determined that the current temperature point is the threshold for battery cooling level degradation or exit.

[0049] 2. Analysis of low temperature thermal management strategy

[0050] 1) Set the vehicle to READY status and shift the gear to D. Set the external temperature control device's inspiration control temperature to -25°C. When the temperature difference between the battery inlet and outlet is consistent with the data at the corresponding temperature recorded in the previous step, and the control time of this temperature point is not less than the control time recorded in the previous step, increase the temperature to -24°C in steps of 1°C. And so on, gradually increase the temperature to 30°C (in line with the range set in the previous step). During the process, at least record the PTC current and voltage, battery water pump current and voltage, battery inlet and outlet temperatures, and liquid-liquid heat exchanger inlet and outlet temperatures;

[0051] 2) During the above-mentioned heating process, when the average temperature of the battery inlet and outlet water reaches a certain temperature, the PTC and the water pump generate current signals, and the inlet temperature of the liquid-liquid heat exchanger increases significantly (measured by a quantitative threshold). At this time, it can be determined that the current temperature point is the threshold for turning on battery heating; and as the internal temperature of the battery increases, the PTC power, water pump power, and the inlet temperature of the liquid-liquid heat exchanger can be used to analyze whether the battery heating demand at the current temperature is downgraded or exited.

[0052] To summarize, the main design concept of the present invention is to connect an external temperature control device to the battery cooling circuit of the whole vehicle; activate the battery management system when the whole vehicle is connected to the charging gun of the DC charging pile and is in a non-charging state; set the temperature control parameters of the external temperature control device and start temperature control according to a predetermined temperature test interval, starting from the endpoint temperature of the interval; when the measured temperatures of the water inlet and outlet of the battery pack and the battery temperature value output by the charging pile meet the established standards, change the temperature control parameters according to a preset gradient and perform temperature control and compliance judgment again; perform temperature control of all temperature control parameters within the temperature test interval in the above manner, and record the control time under each temperature control parameter and the temperature difference between the water inlet and the water outlet; start thermal management strategy analysis, through which the advantages and disadvantages of the thermal management system control of the battery liquid cooling system can be analyzed, thereby improving the thermal management comfort and thermal management energy consumption of new energy vehicles, and thus improving the endurance of the whole vehicle.

[0053] It should also be pointed out here that although the present invention mainly relates to the battery thermal management analysis of the liquid-cooled battery system of new energy vehicles, based on this concept, it can also be combined with the coupling of passenger compartment thermal management and battery thermal management for in-depth analysis, as well as the analysis of high and low temperature charging thermal management, etc., and the present invention is not limited to this.

[0054] If the expressions expressing orientation are mentioned in the embodiments of the present invention, they are relative concepts based on the embodiments. In addition, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c can be single or multiple.

[0055] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the present invention is not limited to the scope of implementation shown in the drawings, and all changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the specification and drawings, should be within the protection scope of the present invention.

Claims

1. A method for analyzing the thermal management control strategy of liquid-cooled batteries for new energy vehicles, characterized in that: include: Connect the external temperature control device to the vehicle battery cooling circuit; When the vehicle is connected to the charging gun of the DC charging pile and is in a non-charging state, activate the battery management system; According to the established temperature test interval, starting from the endpoint temperature of the interval, set the temperature control parameters of the external temperature control device and start the temperature control; When the measured temperatures of the water inlet and outlet of the battery pack and the battery temperature value output by the charging pile meet the established standards, the temperature control parameters are changed according to the preset gradient and the temperature control and compliance determination are performed again; Perform temperature control of all temperature control parameters within the temperature test interval in the above manner, and record the control time under each temperature control parameter and the temperature difference between the water inlet and the water outlet; Start thermal management strategy analysis: Setting the vehicle status and the initial setting value of the external temperature control device; If the current temperature difference between the battery water inlet and outlet and the current control time are measured to meet the established requirements, the temperature is raised and lowered step by step, and the inlet and outlet temperatures of the battery pack, battery pack cooler, liquid-liquid heat exchanger, and the operating parameters of the air-conditioning compressor, battery water pump, and PTC are recorded respectively; During the heating process or the cooling process, the inlet and outlet temperatures and the operating parameters are used to analyze key information of the thermal management strategy, and the key information includes at least any one of the following: a temperature threshold for starting battery cooling, a battery cooling requirement level, a temperature threshold for downgrading or exiting the battery cooling requirement, a temperature threshold for starting battery heating, and a temperature threshold for downgrading or exiting the battery heating requirement.

2. The method for analyzing the thermal management control strategy of a liquid-cooled battery for a new energy vehicle according to claim 1 is characterized in that: After meeting the established requirements, step-by-step temperature increase and temperature decrease control includes: when the current temperature difference is consistent with the temperature difference at the corresponding temperature previously recorded, and the current control time is not less than the control time previously recorded, the temperature is increased or decreased according to the established step length.

3. The method for analyzing the thermal management control strategy of a liquid-cooled battery for a new energy vehicle according to claim 1 is characterized in that: The thermal management strategy analysis includes: high temperature thermal management strategy analysis; During the temperature rise process of the high-temperature thermal management strategy analysis, when the average value of the battery inlet and outlet water temperatures is at the current temperature point, if the compressor and water pump generate current signals and the inlet and outlet temperature difference of the cooler increases, the current temperature point is the start-up temperature threshold for battery cooling; During the cooling process of the high-temperature thermal management strategy analysis, when the average temperature of the battery inlet and outlet water is at the current temperature point, if the current value of the compressor and water pump is reduced or exited, the current temperature point is the temperature threshold for the battery cooling demand to be degraded or exited.

4. The method for analyzing the thermal management control strategy of a liquid-cooled battery for a new energy vehicle according to claim 3 is characterized in that: During the high-temperature thermal management strategy analysis process, as the internal temperature of the battery increases, the battery cooling requirement level corresponding to the current temperature point is obtained through the compressor power and water pump power.

5. The method for analyzing the thermal management control strategy of a liquid-cooled battery for a new energy vehicle according to claim 1, characterized in that: The thermal management strategy analysis includes: low temperature thermal management strategy analysis; During the heating process of the low-temperature thermal management strategy analysis, when the average value of the battery inlet and outlet water temperatures is at the current temperature point, if the PTC and water pump generate current signals and the inlet temperature of the liquid-liquid heat exchanger rises, the current temperature point is the start-up temperature threshold for battery heating.

6. The method for analyzing the thermal management control strategy of a liquid-cooled battery for a new energy vehicle according to claim 5 is characterized in that: During the low-temperature thermal management strategy analysis process, as the internal temperature of the battery increases, the temperature threshold for downgrading or exiting the battery heating demand corresponding to the current temperature point is obtained through the PTC power, water pump power, and the inlet temperature of the liquid-liquid heat exchanger.

7. The method for analyzing the thermal management control strategy of a liquid-cooled battery for a new energy vehicle according to claim 1, characterized in that: The established standard includes: the battery temperature value output by the charging pile is equal to the average value of the measured temperatures of the water inlet and the water outlet.

8. The method for analyzing the thermal management control strategy of a liquid-cooled battery for a new energy vehicle according to any one of claims 1 to 7, characterized in that: The external temperature control device is connected to the liquid cooling water inlet and outlet of the battery pack, and specifically includes: a heating unit, a refrigeration unit and a temperature control unit.

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