Power battery cooling control method and system and charging duration test method and system

Abstract

The invention belongs to the technical field of vehicle power batteries, and particularly relates to a power battery cooling control method and system and a charging duration testing method and system.The power battery cooling control method comprises the steps that the target temperature value of cooling liquid is obtained, and the target temperature value is pre-stored in a control module; a control module is used for controlling a cooling pump on a battery cooling liquid loop to enter a working mode according to battery temperature information, sent by a first temperature sensing assembly, of each single battery, so that cooling liquid circularly flows between the battery cooling liquid loop and a liquid cooling plate assembly, or controlling the cooling pump to enter a shutdown mode; when the cooling pump is in the working mode, the control module is used for dynamically adjusting the refrigeration power of the refrigeration unit on the battery cooling liquid loop according to the outlet temperature information, sent by the second temperature sensing assembly, of the cooling liquid at the outlet of the liquid cooling plate assembly and the pre-stored target temperature value. And the temperature of the cooling liquid at the inlet of the liquid cooling plate assembly is gradually reduced and then is kept at the target temperature value.

Description

Technical Field

[0001] This invention belongs to the field of vehicle power battery technology, specifically relating to a power battery cooling control method and system, and a charging time testing method and system. Background Technology

[0002] The power battery is the energy source for electric vehicles. During charging and discharging, the battery itself generates heat, leading to an increase in temperature. The operating temperature of the power battery directly affects performance parameters such as voltage, internal resistance, capacity, charge / discharge efficiency, safety, and cycle life. The power battery thermal management system is crucial for maintaining the power battery at a suitable operating temperature and improving its performance. Currently, liquid cooling is widely used in power battery cooling control systems due to its advantages such as high heat exchange efficiency, allowing for integrated heating, and ease of maintenance.

[0003] In a power battery cooling control system that uses liquid cooling, predicting the power battery charging time is an important means of verifying the rationality of the structural design of the liquid cooling plate assembly of the power battery cooling control system, and provides important support for optimizing the structural design of the liquid cooling plate assembly.

[0004] Existing methods for predicting the charging time of power batteries typically rely on simulation or bench testing. These methods define the required charging conditions and obtain the charging time. However, when simulating or testing the actual charging process of a power battery under cooling conditions, the common cooling control method involves continuously injecting coolant at the target flow rate and temperature into the inlet of the liquid cooling plate assembly. This approach fails to consider the dynamic changes in coolant temperature at the inlet of the liquid cooling plate assembly and their impact on the battery temperature. This discrepancy between the simulation or bench test and the actual operation of the power battery thermal management system under cooling conditions results in significant errors in the predicted charging time, making it difficult to accurately guide the structural design optimization of the liquid cooling plate assembly.

[0005] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] To address the shortcomings of the prior art, this invention provides a power battery cooling control method, system, and charging time testing method and system, thereby solving the technical problem that the charging time prediction results in the prior art have large errors and cannot accurately guide the structural design optimization of the liquid cooling plate assembly.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A power battery cooling control method includes: obtaining a target temperature value of the coolant and pre-storing the target temperature value in a control module; The control module uses the battery temperature information of each individual cell of the power battery sent from the first temperature sensing component to control the cooling pump on the battery coolant circuit to enter the working mode, so that the coolant circulates between the battery coolant circuit and the liquid cooling plate assembly of the power battery, or controls the cooling pump to enter the shutdown mode. When the cooling pump is in the operating mode, the control module dynamically adjusts the cooling power of the refrigeration unit in the battery coolant circuit based on the coolant outlet temperature information at the outlet of the liquid cooling plate assembly sent from the second temperature sensing component and the pre-stored target temperature value, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value.

[0008] When the power battery cooling control method provided by this invention is used to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions, the coolant temperature curve at the inlet of the liquid cooling plate assembly is closer to the actual coolant temperature curve at the inlet of the liquid cooling plate assembly under charging and cooling conditions during the simulation process. This can reduce the error of the charging time prediction result, improve the accuracy of the charging time prediction, and thus accurately guide the structural design optimization of the liquid cooling plate assembly.

[0009] Furthermore, the method by which the control module dynamically adjusts the cooling power of the refrigeration unit in the battery coolant circuit includes: The maximum cooling power of the refrigeration unit, the output flow rate of the cooling pump, and the density and specific heat capacity of the coolant when the temperature is the target temperature are obtained; and the obtained target temperature, maximum cooling power, output flow rate, density and specific heat capacity are pre-stored in the control module. The control module obtains the target cooling power value of the refrigeration unit based on the received outlet temperature information, as well as the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value. The control module adjusts the cooling power of the cooling unit according to the obtained target cooling power value.

[0010] By utilizing the outlet temperature information acquired by the control module, along with the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value, the cooling power required by the cooling unit to cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value (i.e., the target cooling power value) can be calculated. Then, by adjusting the cooling power of the cooling unit based on the obtained target cooling power value, it can be ensured that, during the actual charging process of the power battery thermal management system under charging and cooling conditions, the cooling power control method provided by this invention can gradually reduce the coolant temperature at the inlet of the liquid cooling plate assembly and maintain it at the target temperature value. This makes the coolant temperature curve at the inlet of the liquid cooling plate assembly during the simulation more closely resemble the actual coolant temperature curve at the inlet of the liquid cooling plate assembly during the actual operation of the power battery thermal management system under charging and cooling conditions.

[0011] Furthermore, the method for obtaining the target cooling power value of the refrigeration unit includes: The control module calculates the maximum temperature threshold of the coolant at the outlet of the liquid cooling plate assembly based on the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value. The control module obtains the target cooling power value of the refrigeration unit based on the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value, as well as the obtained maximum temperature threshold and outlet temperature information.

[0012] Furthermore, the method by which the control module obtains the target cooling power value of the refrigeration unit includes: The control module makes a judgment based on the obtained maximum temperature threshold and the outlet temperature information. If the outlet temperature of the coolant at the outlet of the liquid cooling plate assembly is not less than the maximum temperature threshold, the control module determines that the target cooling power value is equal to the maximum cooling power value. If the outlet temperature value is less than the maximum temperature threshold, the control module calculates the cooling power of the refrigeration unit based on the obtained outlet temperature value, as well as the pre-stored target temperature value, output flow rate value, density value, and specific heat capacity value, and determines that the target cooling power value is equal to the calculated cooling power value.

[0013] By using the control module to pre-calculate the maximum temperature threshold, and determining that the target cooling power value is equal to the maximum cooling power value when the outlet temperature of the coolant at the outlet of the liquid cooling plate assembly is not less than the maximum temperature threshold (that is, when it is determined that even if the cooling power of the refrigeration unit reaches the maximum cooling power value, it is impossible to directly cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value, or it is just able to directly cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value), the control module does not need to perform calculations when the target cooling power value will be not less than the maximum cooling power value, effectively reducing the calculation workload of the control module.

[0014] Furthermore, the maximum temperature threshold is calculated using the following formula: Where T is the maximum temperature threshold; T target The target temperature value; P max C is the maximum cooling power value; Q is the specific heat capacity value; ρ is the output flow rate value; and ρ is the density value.

[0015] Furthermore, the cooling power is calculated using the following formula: Where P1 is the calculated cooling power, T out The outlet temperature value; T target C is the target temperature value; Q is the specific heat capacity value; ρ is the output flow rate value; and ρ is the density value.

[0016] Furthermore, the battery temperature information includes the maximum and average temperature values ​​of each individual cell in the power battery. The method by which the control module controls the cooling pump based on the battery temperature information includes: The control module detects the battery temperature information. If the maximum temperature value is not less than the first preset temperature value T1 and the average temperature value is not less than the second preset temperature value T2, the control module controls the cooling pump to enter the working mode. If the maximum temperature value is not greater than the third preset temperature value T3 and / or the average temperature value is not greater than the fourth preset temperature value T4, the control module controls the cooling pump to enter the shutdown mode. Among them, T1 > T3, T2 > T4.

[0017] Based on the power battery cooling control method provided by the present invention, the present invention also provides a power battery cooling control system, including: a control module, a first temperature sensing component, a second temperature sensing component, a power battery, a battery coolant circuit, a cooling pump and a refrigeration unit installed on the battery coolant circuit; The power battery includes a liquid cooling plate assembly and multiple individual cells; the battery coolant circuit is connected between the inlet and outlet of the liquid cooling plate assembly. The first temperature sensing component is installed on each of the individual cells, and the second temperature sensing component is installed at the outlet of the liquid cooling plate assembly. The control module is used to control the cooling pump to enter the working mode or the shutdown mode according to the battery temperature information of each individual cell sent from the first temperature sensing component. The control module is also used to dynamically adjust the cooling power of the refrigeration unit according to the coolant outlet temperature information at the outlet of the liquid cooling plate assembly sent from the second temperature sensing component when the cooling pump is in the working mode, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value. The power battery cooling control system is used to execute the steps in the power battery cooling control method provided by the present invention.

[0018] The power battery cooling control system provided by this invention can be used to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions, thereby reducing the error of the charging time prediction result, improving the accuracy of the charging time prediction, and thus accurately guiding the structural design optimization of the liquid cooling plate assembly. It can also be used as the power battery cooling control system of a vehicle (that is, as at least part of the vehicle's power battery thermal management system). Based on the control module's control logic that when the cooling pump is in the working mode, it dynamically adjusts the cooling power of the refrigeration unit according to the received outlet temperature information, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is maintained at the target temperature value, when the power battery cooling control system provided by this invention is used as the power battery cooling control system of a vehicle, the temperature of the power battery can be maintained within a suitable temperature range while the cooling power of the refrigeration unit can be reasonably adjusted to reduce energy consumption.

[0019] Based on the power battery cooling control method provided by this invention, this invention also provides a power battery charging time testing method, including: Obtain the first design parameter information of the power battery, the power parameter information of the cooling unit, the second design parameter information of the cooling pump, the physical property parameter information of the coolant, and the standard parameter information of the charging equipment; A power battery cooling control submodule is established based on the first design parameter information, the power parameter information, the second design parameter information, the physical property parameter information, and the power battery cooling control method provided by the present invention; a charging equipment submodule is established based on the standard parameter information. A charging test model is established by combining the power battery cooling control submodule and the charging equipment submodule; the charging test model is a physical model or a simulation model. Based on the initial constraints of the power battery charging test, the power battery charging test is performed through the charging test model. During the test, the power battery in the power battery cooling control submodule is charged using the charging equipment submodule, and the steps in the power battery cooling control method provided by the present invention are executed using the power battery cooling control submodule. After completing the power battery charging test, the charging time information of the power battery is obtained.

[0020] By setting initial constraints for the power battery charging test before performing the charging test using the charging test model, testers can set the initial constraints according to test needs before using the power battery charging time test method provided by this invention to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions under different initial constraints, thereby improving the versatility and comprehensiveness of the power battery charging time test method.

[0021] The first design parameter information includes the performance parameters of each individual cell of the power battery and the structural parameters of the liquid cooling plate assembly of the power battery.

[0022] For ease of understanding, establishing a power battery cooling control sub-module based on the first design parameter information, the power parameter information, the second design parameter information, the physical property parameter information, and the power battery cooling control method provided by this invention can also be described as establishing a simulation sub-model or physical sub-model of the power battery cooling control system provided by this invention based on the first design parameter information, the power parameter information, the second design parameter information, the physical property parameter information, and the power battery cooling control method provided by this invention.

[0023] Furthermore, the initial constraints include the test environment temperature, the initial average temperature of each individual cell in the power battery cooling control submodule, and the initial temperature of the coolant in the power battery cooling control submodule.

[0024] The present invention also provides a power battery charging time testing system, comprising: a physical model established using the power battery charging time testing method provided by the present invention; The charging test entity model is used to perform power battery charging tests and obtain power battery charging time information.

[0025] The present invention also provides a computer program, which includes a simulation model established using the power battery charging time test method provided by the present invention; When the simulation model is run on a computer, a power battery charging test is performed to obtain the charging time information of the power battery. Attached Figure Description

[0026] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart of the power battery cooling control method in Example 1; Figure 2 This is a flowchart of the method for the control module to control the cooling pump and refrigeration unit in Embodiment 1; Figure 3 This is a comparison chart of the inlet water temperature change curves in Example 1; Figure 4 This is a comparison chart of the outlet water temperature change curves in Example 1; Figure 5 This is a comparison chart of the cooling power curves of the cooling unit in Example 1; Figure 6 This is a comparison graph of the charging current and SOC variation curves in Example 1; Figure 7 This is a schematic diagram of the power battery cooling control system in Example 2; Among them, 1—power battery, 2—cooling pump, 3—condenser, 4—compressor, 5—evaporator, 6—first expansion valve, 7—battery cooler, and 8—second expansion valve. Detailed Implementation

[0028] The power battery is the energy source for electric vehicles. During charging and discharging, the battery itself generates heat, leading to an increase in temperature. The operating temperature of the power battery directly affects performance parameters such as voltage, internal resistance, capacity, charging and discharging efficiency, safety, and cycle life. Specifically, the charging current of the power battery is determined by both the battery temperature and the state of charge (SOC), which can be expressed in the form of the following two-dimensional table: Among them, I i,jThe battery temperature is T. i And the state of charge is SOC j The corresponding charging current at that time.

[0029] The current relationship between SOC and charging current is as follows: Where C is the rated capacity of the battery cell; SOC tx State of Charge (SOC) is the battery charge level at time tx during the charging process. t0 I represents the battery charge level at time t0 (or the initial time) during the charging process; ti This represents the charging current of the battery at time ti during the charging process.

[0030] It can be seen that during the charging process, the charging current will change as the battery temperature and SOC change.

[0031] Therefore, the thermal management system of a power battery is crucial for maintaining the battery at a suitable operating temperature and improving its performance. Currently, liquid cooling is widely used in power battery cooling control systems due to its advantages such as high heat exchange efficiency, allowing for integrated heating, and ease of maintenance.

[0032] In a power battery cooling control system that uses liquid cooling, predicting the power battery charging time is an important means of verifying the rationality of the structural design of the liquid cooling plate assembly of the power battery cooling control system, and provides important support for optimizing the structural design of the liquid cooling plate assembly.

[0033] Existing methods for predicting the charging time of power batteries typically rely on simulation or bench testing. These methods define the required charging conditions to obtain the charging time and conditions (including at least the actual charging process under cooling conditions). However, in simulating or bench testing the actual charging process of power batteries, the commonly used cooling control method involves continuously injecting coolant at a target flow rate and target temperature into the inlet of the liquid cooling plate assembly. This approach fails to consider the dynamic changes in coolant temperature at the inlet of the liquid cooling plate assembly and their impact on the battery temperature. This discrepancy with the actual operation of the power battery thermal management system under cooling conditions leads to significant errors in the predicted charging time, hindering accurate guidance for optimizing the structural design of the liquid cooling plate assembly.

[0034] To address the shortcomings of the prior art, this invention provides a power battery cooling control method, system, and charging time testing method and system to solve the technical problem that the charging time prediction results in the prior art have large errors and cannot accurately guide the structural design optimization of the liquid cooling plate assembly.

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] Example 1: like Figure 1 As shown, this embodiment 1 provides a power battery cooling control method, including: obtaining a target temperature value of the coolant and pre-storing the target temperature value in the control module; The control module uses the battery temperature information of each cell of the power battery sent from the first temperature sensing component to control the cooling pump on the battery coolant circuit to enter the working mode, so that the coolant circulates between the battery coolant circuit and the liquid cooling plate assembly of the power battery, or controls the cooling pump to enter the shutdown mode. When the cooling pump is in working mode, the control module dynamically adjusts the cooling power of the cooling unit on the battery coolant circuit based on the coolant outlet temperature information at the outlet of the liquid cooling plate assembly sent from the second temperature sensing component, as well as the pre-stored target temperature value, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value.

[0037] When the power battery cooling control method provided by this invention is used to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions, the coolant temperature curve at the inlet of the liquid cooling plate assembly is closer to the actual coolant temperature curve at the inlet of the liquid cooling plate assembly under charging and cooling conditions during the simulation process. This reduces the error of the charging time prediction result, improves the accuracy of the charging time prediction, and thus accurately guides the structural design optimization of the liquid cooling plate assembly.

[0038] In one embodiment, the method for the control module to dynamically adjust the cooling power of the cooling unit in the battery coolant circuit includes: The system obtains the maximum cooling power of the refrigeration unit, the output flow rate of the cooling pump, and the density and specific heat capacity of the coolant when the temperature is the target temperature. The system then stores the target temperature, maximum cooling power, output flow rate, density, and specific heat capacity values ​​in the control module. The control module obtains the target cooling power value of the refrigeration unit based on the received outlet temperature information, as well as the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value and specific heat capacity value. The control module adjusts the cooling power of the cooling unit based on the obtained target cooling power value.

[0039] By utilizing the outlet temperature information acquired by the control module, along with pre-stored target temperature, maximum cooling power, output flow rate, density, and specific heat capacity, the cooling power required by the cooling unit to cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature (i.e., the target cooling power value) can be calculated. Then, by adjusting the cooling power of the cooling unit based on the obtained target cooling power value, it can be ensured that, during the actual charging process of the power battery thermal management system under charging and cooling conditions, the cooling power of the liquid cooling plate assembly can be gradually reduced and maintained at the target temperature value. This makes the coolant temperature curve at the inlet of the liquid cooling plate assembly during the simulation more closely resemble the actual coolant temperature curve at the inlet of the liquid cooling plate assembly during the actual operation of the power battery thermal management system under charging and cooling conditions.

[0040] In one embodiment, the method for obtaining the target cooling power value of the cooling unit includes: The control module calculates the maximum temperature threshold of the coolant at the outlet of the liquid cooling plate assembly based on the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value. The control module obtains the target cooling power value of the refrigeration unit based on the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, specific heat capacity value, as well as the obtained maximum temperature threshold and outlet temperature information.

[0041] Specifically, in this embodiment 1, the method by which the control module obtains the target value of the cooling power of the cooling unit includes: The control module makes a judgment based on the obtained maximum temperature threshold and outlet temperature information. If the outlet temperature of the coolant at the outlet of the liquid cooling plate assembly is not less than the maximum temperature threshold, the control module determines that the target cooling power value is equal to the maximum cooling power value. If the outlet temperature value is less than the maximum temperature threshold, the control module calculates the cooling power of the cooling unit based on the obtained outlet temperature value, as well as the pre-stored target temperature value, output flow rate value, density value, and specific heat capacity value, and determines that the target cooling power value is equal to the calculated cooling power value.

[0042] By using the control module to pre-calculate the maximum temperature threshold, and determining that the target cooling power value is equal to the maximum cooling power value when the outlet temperature of the coolant at the outlet of the liquid cooling plate assembly is not less than the maximum temperature threshold (that is, when it is determined that even if the cooling power of the refrigeration unit reaches the maximum cooling power value, it is still impossible to directly cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value, or it is just able to directly cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value), the control module does not need to perform calculations when the target cooling power value will not be less than the maximum cooling power value, effectively reducing the calculation workload of the control module.

[0043] In one embodiment, the maximum temperature threshold is calculated using the following formula: Where T is the maximum temperature threshold; T target The target temperature value; P max ρ is the maximum cooling power; C is the specific heat capacity; Q is the output flow rate; ρ is the density.

[0044] In one embodiment, the cooling power is calculated using the following formula: Where P1 is the calculated cooling power, T out This refers to the outlet temperature value; T target ρ is the target temperature; C is the specific heat capacity; Q is the output flow rate; and ρ is the density.

[0045] In one embodiment, such as Figure 2 As shown, the battery temperature information includes the maximum and average temperature values ​​of each individual cell in the power battery. The control module controls the cooling pump based on battery temperature information in the following ways: The control module detects battery temperature information. If the maximum temperature value detected is not less than the first preset temperature value T1 and the average temperature value is not less than the second preset temperature value T2, the control module controls the cooling pump to enter the working mode. If the maximum temperature value detected is not greater than the third preset temperature value T3 and / or the average temperature value detected is not greater than the fourth preset temperature value T4, the control module controls the cooling pump to enter the shutdown mode. Among them, T1 > T3, T2 > T4.

[0046] It should be noted that in this embodiment 1, when the power battery starts charging, the cooling pump will set an initial mode, which is either the working mode or the shutdown mode. When the initial mode is set to shutdown mode, the control module will only control the cooling pump to enter the working mode for the first time when the control module detects that the maximum temperature value is not less than the first preset temperature value T1 and the average temperature value is not less than the second preset temperature value T2. When the initial mode is set to working mode, the control module will only control the cooling pump to enter the shutdown mode for the first time when the control module detects that the maximum temperature value is not greater than the third preset temperature value T3 and / or detects that the average temperature value is not greater than the fourth preset temperature value T4.

[0047] To facilitate understanding, this invention also provides a comparative experiment between a power battery charging test based on the power battery cooling control method provided in Example 1 (hereinafter referred to as the verification group) and a power battery charging test based on the existing power battery cooling control method (hereinafter referred to as the control group) as an example to illustrate the technical effects of this invention. The comparative experiment is as follows: In both the verification group and the control group tests, the ambient temperature and the initial average temperature of each individual cell of the power battery were set to 40℃, and the target temperature of the coolant was set to 20℃.

[0048] In the verification group, since the test environment temperature and the initial average temperature of each individual cell of the power battery were both set to 40℃, the initial temperature of the coolant in the battery coolant circuit and the liquid cooling plate assembly was also set to 40℃.

[0049] In the control group, the power battery was cooled by continuously injecting 20°C coolant at the inlet of the liquid cooling plate assembly at a target flow rate.

[0050] After comparative experiments, a comparison chart of inlet water temperature change curves can be obtained (e.g., Figure 3 A comparison chart of the outlet water temperature change curves (as shown) and the curves shown in the figure. Figure 4 (as shown), here Figure 3 and Figure 4 The given curve comparison chart is just one example, showing only the comparison results where the difference between the two is the smallest, and does not show all the comparison results (such as the comparison results when the maximum cooling power configuration of the refrigeration unit is too small).

[0051] like Figure 3 As shown, in the control group, the coolant temperature at the inlet of the liquid cooling plate assembly was kept constant at 20°C of the target temperature (i.e., Figure 3 As shown by the "constant inlet water temperature" line in the test, in the verification group, the coolant temperature at the inlet of the liquid cooling plate assembly was a dynamically changing curve for a period of time in the initial stage of the test, until it finally reached the target temperature value and stabilized (i.e., ...). Figure 3 (As shown by the "Inlet Dynamic Water Temperature" line in the image).

[0052] Clearly, the coolant temperature change at the inlet of the liquid cooling plate assembly in the verification group is closer to the actual coolant temperature change at the inlet of the liquid cooling plate assembly during the charging process of the power battery thermal management system under charging cooling conditions.

[0053] Especially when the maximum cooling power of the cooling unit is too small, the coolant temperature at the inlet of the liquid cooling plate assembly may not be able to drop to the target temperature value until the end of the charging process under the charging and cooling conditions of the power battery thermal management system. This will result in a greater deviation from the coolant temperature change at the inlet of the liquid cooling plate assembly in the control group. However, under the same conditions, the coolant temperature change at the inlet of the liquid cooling plate assembly in the verification group can still closely match the coolant temperature change at the inlet of the liquid cooling plate assembly in the actual charging process under the charging and cooling conditions of the power battery thermal management system.

[0054] like Figure 4 As shown, in the control group, the coolant temperature at the outlet of the liquid cooling plate assembly exhibited a sharp downward trend (i.e., Figure 4 The line in the diagram shows the "outlet water temperature corresponding to constant inlet water temperature," while in the verification group, the coolant temperature change at the outlet of the liquid cooling plate assembly was relatively slow (i.e., Figure 4 The line showing "outlet water temperature corresponding to inlet dynamic water temperature" more closely reflects the actual coolant temperature change at the outlet of the liquid cooling plate assembly during the charging process of the power battery thermal management system under charging and cooling conditions.

[0055] In summary, during the verification group's tests, when the coolant temperature at the inlet of the liquid cooling plate assembly was dynamically changing, the refrigeration unit dynamically adjusted its refrigeration power by coupling and iterating the coolant temperature at the outlet of the liquid cooling plate assembly with the coolant temperature at the inlet of the liquid cooling plate assembly. This method better reflects actual operating conditions and improves the accuracy of charging time prediction.

[0056] like Figure 5 As shown, in the verification group's tests, for a period of time after the start of the power battery charging test, the coolant temperature at the outlet of the liquid cooling plate assembly was not lower than the maximum temperature threshold. At this time, the cooling power of the refrigeration unit (if the refrigeration unit uses a battery cooler installed on the air conditioning circuit to exchange heat with the battery coolant circuit, then the cooling power of the refrigeration unit at this time is also the heat exchange power of the battery cooler) can reach the maximum cooling power. As the power battery charging test progresses, the cooling power will gradually decrease until it basically stabilizes (i.e., Figure 5 The line indicating "cooling power of the cold plate corresponding to the inlet dynamic water temperature" is shown in the figure. However, in the control group test, the corresponding cooling power for a period of time after the start of the test (since the control group continuously injects coolant at 20°C at the inlet of the liquid cooling plate assembly at the target flow rate, the cooling power here is the calculated equivalent power) was consistently much greater than the maximum cooling power in the verification group test (i.e., Figure 5As shown by the line "Heat exchange power of the cold plate corresponding to constant inlet water temperature" in the figure, using a control group to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions can lead to overly idealized charging time predictions. The predicted charging time will have a relatively large error compared to the actual charging time. The results of the above comparative experiment also verify this problem. In the above comparative experiment, the charging time predicted by the control group was two minutes and twenty-four seconds shorter than the charging time predicted by the verification group (e.g., ...). Figure 6 (As shown).

[0057] It should be noted that during the charging process of the power battery, both the initial trickle charging stage (0% to 20% capacity in this comparative experiment) and the final constant voltage charging stage (80% to 100% capacity in this comparative experiment) involve low-current charging. Therefore, the temperature of the power battery has a minimal impact on the charging current. Consequently, the time spent in the initial trickle charging stage and the final constant voltage charging stage are essentially the same for both the verification group and the control group. Figure 6 The data presented only show the experimental data of the validation and control groups during the mid-term fast charging phase. Figure 6 The "charging current at constant water temperature" line is the charging current-time curve of the control group during the fast charging phase in the middle stage; the "charging current at dynamic water temperature" line is the charging current-time curve of the verification group during the fast charging phase in the middle stage; the "SOC at constant water temperature" line is the SOC-time curve of the control group during the fast charging phase in the middle stage; and the "SOC at dynamic water temperature" line is the SOC-time curve of the verification group during the fast charging phase in the middle stage.

[0058] Example 2: Based on the power battery cooling control method provided in Embodiment 1, Embodiment 2 provides a power battery cooling control system, including: a control module, a first temperature sensing component, a second temperature sensing component, a power battery, a battery coolant circuit, a cooling pump and a refrigeration unit installed on the battery coolant circuit; The power battery includes a liquid cooling plate assembly and multiple individual cells; the battery coolant circuit is connected between the inlet and outlet of the liquid cooling plate assembly. The first temperature sensing component is installed on each individual cell, and the second temperature sensing component is installed at the outlet of the liquid cooling plate assembly. The control module is used to control the cooling pump to enter the working mode or the shutdown mode based on the battery temperature information of each individual cell sent from the first temperature sensing component. The control module is also used to dynamically adjust the cooling power of the refrigeration unit based on the coolant outlet temperature information at the outlet of the liquid cooling plate assembly sent from the second temperature sensing component when the cooling pump is in working mode, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value. The power battery cooling control system is used to execute the steps in the power battery cooling control method provided in Example 1.

[0059] The power battery cooling control system provided by this invention can be used to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions, thereby reducing the error of the charging time prediction test and improving the accuracy of charging time prediction, thus accurately guiding the structural design optimization of the liquid cooling plate assembly. It can also be used as the power battery cooling control system of a vehicle (i.e., as at least part of the vehicle's power battery thermal management system). Based on the control logic that the control module dynamically adjusts the cooling power of the refrigeration unit according to the received outlet temperature information when the cooling pump is in working mode, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value, when the power battery cooling control system provided by this invention is used as the power battery cooling control system of a vehicle, the temperature of the power battery can be maintained within a suitable temperature range while the cooling power of the refrigeration unit is reasonably adjusted to reduce energy consumption.

[0060] For ease of understanding, an example of the specific configuration structure of the power battery cooling control system is given in this embodiment 2, as follows: like Figure 7 As shown, in this example, the power battery cooling control system includes a control module, a first temperature sensing component, a second temperature sensing component, a power battery 1, a battery coolant circuit, a cooling pump 2 installed on the battery coolant circuit, and a refrigeration unit. The power battery 1 includes multiple individual cells and a liquid cooling plate assembly; the battery coolant circuit is connected between the inlet and outlet of the liquid cooling plate assembly; The first temperature sensing component is installed on each individual cell, and the second temperature sensing component is installed at the outlet of the liquid cooling plate assembly. The control module is used to control the cooling pump 2 to enter the working mode or the shutdown mode based on the battery temperature information of each individual cell sent from the first temperature sensing component. The control module is also used to dynamically adjust the cooling power of the refrigeration unit based on the coolant outlet temperature information at the outlet of the liquid cooling plate assembly sent from the second temperature sensing component when the cooling pump 2 is in working mode, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value. The power battery cooling control system is used to execute the steps in the power battery cooling control method provided in Example 1.

[0061] Specifically, in this example, such as Figure 7 As shown, the refrigeration unit includes a compressor branch, a crew cabin refrigeration branch, and a battery cooling branch arranged in parallel; A condenser 3 and a compressor 4 are sequentially installed on the compressor branch; a first expansion valve 6 and an evaporator 5 are sequentially installed on the crew cabin cooling branch; and a second expansion valve 8 and a battery cooler 7 are sequentially installed on the battery cooling branch. The battery cooler 7 is connected between the battery cooling branch and the battery coolant circuit. The battery cooler 7 is used to transfer heat from the battery coolant circuit to the battery cooling branch.

[0062] In this example, the cooling power of the refrigeration unit is also the heat exchange power of the battery cooler 7. The function of the control module to adjust the cooling power of the refrigeration unit (i.e., the heat exchange power of the battery cooler 7) can be achieved by controlling the opening degree of the second expansion valve 8 and / or the speed of the compressor 4 through the control module.

[0063] The mapping relationship between the opening degree of the second expansion valve 8 and / or the rotational speed of the compressor 4 and the cooling power of the refrigeration unit (i.e., the heat exchange power of the battery cooler 7) can be obtained through calibration testing. The specific calibration testing method is common knowledge in the field and will not be described in detail in this invention.

[0064] It should be noted that this example is only a specific application example of the present invention (especially regarding the structural part of the refrigeration unit, various refrigeration units that can adjust the refrigeration power through the control module can be used; the above example is only an example of a vehicle air conditioning system that integrates passenger compartment cooling and power battery cooling as a refrigeration unit), and does not constitute any limitation on the scope of protection of the present invention.

[0065] Example 3: Based on the power battery cooling control method provided in Example 1, Example 3 provides a power battery charging time testing method, including: Obtain the first design parameter information of the power battery, the power parameter information of the cooling unit, the second design parameter information of the cooling pump, the physical property parameter information of the coolant, and the standard parameter information of the charging equipment; A power battery cooling control submodule is established based on the first design parameter information, power parameter information, second design parameter information, physical property parameter information, and the power battery cooling control method provided in Example 1; a charging equipment submodule is established based on the standard parameter information. A charging test model is established by combining the power battery cooling control submodule and the charging equipment submodule; the charging test model can be a physical model or a simulation model. Based on the initial constraints of the power battery charging test, the power battery charging test is executed through the charging test model. During the test, the power battery in the power battery cooling control submodule is charged using the charging equipment submodule, and the steps in the power battery cooling control method provided in Example 1 are executed using the power battery cooling control submodule. After completing the power battery charging test, the charging time information of the power battery is obtained.

[0066] By setting initial constraints for the power battery charging test before using the charging test model, testers can set the initial constraints according to test needs before using the power battery charging time test method provided by this invention. This allows the test to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions under different initial constraints, thus improving the versatility and comprehensiveness of the power battery charging time test method.

[0067] By making the established charging test model either a physical model or a simulation model, the established simulation model can be used to perform power battery charging tests, saving the cost required to establish a physical model and improving testing efficiency; alternatively, the established physical model can be used to perform power battery charging tests, thereby improving the accuracy of the tests and enhancing the flexibility and versatility of the power battery charging time testing method provided by this invention.

[0068] Specifically, in this embodiment 3, the first design parameter information includes the performance parameters of each individual cell of the power battery and the structural parameters of the liquid cooling plate assembly of the power battery.

[0069] For ease of understanding, the establishment of a power battery cooling control sub-module based on the first design parameter information, power parameter information, second design parameter information, physical property parameter information, and the power battery cooling control method provided in Example 1 can also be described as establishing a simulation sub-model or physical sub-model of the power battery cooling control system provided in Example 2 based on the first design parameter information, power parameter information, second design parameter information, physical property parameter information, and the power battery cooling control method provided in Example 1.

[0070] Specifically, in this embodiment 3, the initial constraints include the test environment temperature, the initial average temperature of each individual cell of the power battery in the power battery cooling control submodule, and the initial temperature of the coolant in the power battery cooling control submodule.

[0071] Example 4: Example 4 provides a power battery charging time testing system, including: a physical model established using the power battery charging time testing method provided in Example 3; The charging test entity model is used to perform power battery charging tests and obtain charging time information of the power battery.

[0072] Example 5: Example 5 provides a computer program, which includes a simulation model established using the power battery charging time test method provided in Example 3; When the simulation model is run on a computer, a power battery charging test is performed to obtain information on the charging time of the power battery.

[0073] The power battery cooling control method, system, and charging time testing method and system provided by this invention have at least the following technical effects or advantages: 1. When the power battery cooling control method provided by this invention is used to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions, the coolant temperature curve at the inlet of the liquid cooling plate assembly is closer to the actual coolant temperature curve at the inlet of the liquid cooling plate assembly under charging and cooling conditions during the simulation process. This reduces the error of the charging time prediction result, improves the accuracy of the charging time prediction, and thus accurately guides the structural design optimization of the liquid cooling plate assembly.

[0074] 2. By utilizing the outlet temperature information acquired by the control module, along with pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value, the cooling power required by the cooling unit to cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value (i.e., the target cooling power value) can be calculated. Then, by adjusting the cooling power of the cooling unit based on the obtained target cooling power value, it can be ensured that the cooling control method for power batteries provided by this invention can gradually reduce the coolant temperature at the inlet of the liquid cooling plate assembly and maintain it at the target temperature value during the actual charging process of the power battery thermal management system under charging and cooling conditions. This makes the coolant temperature curve at the inlet of the liquid cooling plate assembly during the simulation process closer to the coolant temperature curve at the inlet of the liquid cooling plate assembly during the actual operation of the power battery thermal management system under charging and cooling conditions.

[0075] 3. By using the control module to pre-calculate the maximum temperature threshold, and when the outlet temperature of the coolant at the outlet of the liquid cooling plate assembly is not less than the maximum temperature threshold (that is, when it is determined that even if the cooling power of the refrigeration unit reaches the maximum cooling power value, it is still impossible to directly cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value, or it is just able to directly cool the coolant at the inlet of the liquid cooling plate assembly to the target temperature value), the target cooling power value is determined to be equal to the maximum cooling power value. This eliminates the need for the control module to perform calculations when the target cooling power value will be not less than the maximum cooling power value, effectively reducing the calculation workload of the control module.

[0076] 4. The power battery cooling control system provided by this invention can be used to simulate the actual charging process of the power battery thermal management system under charging and cooling conditions, so as to reduce the error of the charging time prediction result, improve the accuracy of the charging time prediction, and thus accurately guide the structural design optimization of the liquid cooling plate assembly; it can also be used as the power battery cooling control system of a vehicle (that is, as at least part of the vehicle's power battery thermal management system). Based on the control logic that the control module dynamically adjusts the cooling power of the refrigeration unit according to the received outlet temperature information when the cooling pump is in working mode, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is maintained at the target temperature value, when the power battery cooling control system provided by this invention is used as the power battery cooling control system of a vehicle, the temperature of the power battery can be maintained within a suitable temperature range while the cooling power of the refrigeration unit can be reasonably adjusted to reduce energy consumption.

[0077] 5. By setting initial constraints for the power battery charging test before using the charging test model to perform the power battery charging test, testers can set the initial constraints according to test needs before using the power battery charging time test method provided by this invention to perform the power battery charging test. This can simulate the actual charging process of the power battery thermal management system under charging and cooling conditions under different initial constraints, thereby improving the versatility and comprehensiveness of the power battery charging time test method.

[0078] 6. By establishing a charging test model, which can be either a physical model or a simulation model, the established simulation model can be used to conduct power battery charging tests, thereby saving the cost required to establish a physical model and improving testing efficiency; alternatively, the established physical model can be used to conduct power battery charging tests, thereby improving the accuracy of the tests and enhancing the flexibility and versatility of the power battery charging time testing method provided by this invention.

[0079] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. All technical solutions formed by equivalent transformation or equivalent substitution fall within the scope of protection of the present invention.

Claims

1. A method for controlling the cooling of a power battery, characterized in that, include: Obtain the target temperature value of the coolant and pre-store the target temperature value in the control module; The control module uses the battery temperature information of each individual cell of the power battery sent from the first temperature sensing component to control the cooling pump on the battery coolant circuit to enter the working mode, so that the coolant circulates between the battery coolant circuit and the liquid cooling plate assembly of the power battery, or controls the cooling pump to enter the shutdown mode. When the cooling pump is in the operating mode, the control module dynamically adjusts the cooling power of the refrigeration unit in the battery coolant circuit based on the coolant outlet temperature information at the outlet of the liquid cooling plate assembly sent from the second temperature sensing component and the pre-stored target temperature value, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value.

2. The power battery cooling control method according to claim 1, characterized in that, The method by which the control module dynamically adjusts the cooling power of the refrigeration unit in the battery coolant circuit includes: The maximum cooling power of the refrigeration unit, the output flow rate of the cooling pump, and the density and specific heat capacity of the coolant when the temperature is the target temperature are obtained; and the obtained target temperature, maximum cooling power, output flow rate, density and specific heat capacity are pre-stored in the control module. The control module obtains the target cooling power value of the refrigeration unit based on the received outlet temperature information, as well as the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value. The control module adjusts the cooling power of the cooling unit according to the obtained target cooling power value.

3. The power battery cooling control method according to claim 2, characterized in that, The method for obtaining the target cooling power value of the refrigeration unit includes: The control module calculates the maximum temperature threshold of the coolant at the outlet of the liquid cooling plate assembly based on the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value. The control module obtains the target cooling power value of the refrigeration unit based on the pre-stored target temperature value, maximum cooling power value, output flow rate value, density value, and specific heat capacity value, as well as the obtained maximum temperature threshold and outlet temperature information.

4. The power battery cooling control method according to claim 3, characterized in that: The method by which the control module obtains the target cooling power value of the refrigeration unit includes: The control module makes a judgment based on the obtained maximum temperature threshold and the outlet temperature information. If the outlet temperature of the coolant at the outlet of the liquid cooling plate assembly is not less than the maximum temperature threshold, the control module determines that the target cooling power value is equal to the maximum cooling power value. If the outlet temperature value is less than the maximum temperature threshold, the control module calculates the cooling power of the refrigeration unit based on the obtained outlet temperature value, as well as the pre-stored target temperature value, output flow rate value, density value, and specific heat capacity value, and determines that the target cooling power value is equal to the calculated cooling power value.

5. The power battery cooling control method according to claim 1, characterized in that: The battery temperature information includes the maximum and average temperature values ​​of each individual cell in the power battery. The method by which the control module controls the cooling pump based on the battery temperature information includes: The control module detects the battery temperature information. If the maximum temperature value is not less than the first preset temperature value T1 and the average temperature value is not less than the second preset temperature value T2, the control module controls the cooling pump to enter the working mode. If the maximum temperature value is not greater than the third preset temperature value T3 and / or the average temperature value is not greater than the fourth preset temperature value T4, the control module controls the cooling pump to enter the shutdown mode. Among them, T1 > T3, T2 > T4.

6. A power battery cooling control system, characterized in that, include: The system includes a control module, a first temperature sensing component, a second temperature sensing component, a power battery, a battery coolant circuit, a cooling pump and a refrigeration unit installed on the battery coolant circuit. The power battery includes a liquid cooling plate assembly and multiple individual cells; the battery coolant circuit is connected between the inlet and outlet of the liquid cooling plate assembly. The first temperature sensing component is installed on each of the individual cells, and the second temperature sensing component is installed at the outlet of the liquid cooling plate assembly. The control module is used to control the cooling pump to enter the working mode or the shutdown mode according to the battery temperature information of each individual cell sent from the first temperature sensing component. The control module is also used to dynamically adjust the cooling power of the refrigeration unit according to the coolant outlet temperature information at the outlet of the liquid cooling plate assembly sent from the second temperature sensing component when the cooling pump is in the working mode, so that the coolant temperature at the inlet of the liquid cooling plate assembly gradually decreases and is then maintained at the target temperature value. The power battery cooling control system is used to execute the steps in the power battery cooling control method according to any one of claims 1-5.

7. A method for testing the charging time of a power battery, characterized in that, include: Obtain the first design parameter information of the power battery, the power parameter information of the cooling unit, the second design parameter information of the cooling pump, the physical property parameter information of the coolant, and the standard parameter information of the charging equipment; A power battery cooling control submodule is established based on the first design parameter information, the power parameter information, the second design parameter information, the physical property parameter information, and the power battery cooling control method as described in any one of claims 1-5; a charging equipment submodule is established based on the standard parameter information; A charging test model is established by combining the power battery cooling control submodule and the charging equipment submodule; the charging test model is a physical model or a simulation model. Based on the initial constraints of the power battery charging test, the power battery charging test is performed through the charging test model; during the test, the power battery in the power battery cooling control submodule is charged using the charging equipment submodule, and the steps in the power battery cooling control method as described in any one of claims 1-5 are performed using the power battery cooling control submodule. After completing the power battery charging test, the charging time information of the power battery is obtained.

8. The method for testing the charging time of a power battery according to claim 7, characterized in that: The initial constraints include the test environment temperature, the initial average temperature of each individual cell in the power battery cooling control submodule, and the initial temperature of the coolant in the power battery cooling control submodule.

9. A power battery charging time testing system, characterized in that, include: A physical model established using the power battery charging time test method described in claim 7 or 8; The charging test entity model is used to perform power battery charging tests and obtain power battery charging time information.

10. A computer program, characterized in that, The computer program includes a simulation model established using the power battery charging time test method described in claim 7 or 8; When the simulation model is run on a computer, a power battery charging test is performed to obtain the charging time information of the power battery.

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