Power battery thermal management method, device, equipment and medium

Abstract

The invention discloses a thermal management method for a power battery. The thermal management method comprises the steps that the working state of a whole vehicle battery management system BMS is recognized; acquiring the battery temperature of the battery and the thermal management characteristic parameter of the current working condition; determining a corresponding thermal management mode according to the battery temperature; and controlling thermal management characteristic parameters of the current working condition according to the working state of the BMS and the thermal management mode. By dynamically identifying the working state of the battery management system and the battery temperature parameters, differentiated thermal management modes are established, accurate temperature control is achieved, and the method has the advantages that the energy efficiency ratio of the thermal management system is increased, and the charging efficiency is optimized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power battery of vehicle, and in particular to a power battery thermal management method and device, vehicle, equipment and medium. BACKGROUND

[0002] As a core component of new energy vehicles, the electrochemical performance of the power battery has a great influence on the power and safety of the vehicle, and the electrochemical performance is highly sensitive to the battery temperature. According to the electrochemical characteristics of the battery, the optimal charging temperature of the battery usually needs to be controlled in a suitable range (usually 15-35℃). The battery management system BMS (Battery Management System, BMS) usually limits the charging current at ultra-low temperature or ultra-high temperature, resulting in prolonged charging time. In low temperature working conditions (below-20℃), the charging efficiency will drop sharply, and there is a risk of lithium dendrite precipitation; in high temperature environment (more than 40℃), it is easy to cause thermal runaway precursors such as electrolyte decomposition and SEI (Solid Electrolyte Interphase) film failure. Such harsh thermal boundary conditions put forward higher precision control requirements for the thermal management system TMS (Engine Thermal Management System, TMS).

[0003] In the scenario of charging while parking, the core task of the TMS is to dynamically adjust the charging strategy to maintain the battery temperature in a safe and efficient range, so as to improve the charging rate, prevent battery thermal runaway and prolong the battery life. The current technology fails to establish differentiated thermal management strategies for different working conditions, resulting in low system energy efficiency.

[0004] In view of the above-mentioned problems of the prior art, the prior art needs to be improved. SUMMARY

[0005] In view of the above-mentioned problems of the prior art, the present application provides a power battery thermal management method, device, vehicle, equipment and medium, which is used to solve at least one defect in the prior art.

[0006] The power battery thermal management method provided by the present application comprises: identifying the working state of the vehicle battery management system BMS; obtaining the battery temperature and the current working condition thermal management characteristic parameter of the battery; determining the corresponding thermal management mode according to the battery temperature; controlling the current working condition thermal management characteristic parameter according to the working state of the battery management system BMS and the thermal management mode.

[0007] In an embodiment of the present application, the current working condition thermal management characteristic parameter is controlled according to the working state of the battery management system BMS and the thermal management mode, including: When the working state of the battery management system BMS is a slow charging state; If the thermal management mode is a pure heating mode, the thermal management system TMS heats the battery at a maximum heating power and a maximum cooling water pump flow until the battery temperature reaches a first target temperature within a first time; If the thermal management mode is a charging and heating mode or a charging and cooling mode, a temperature change trend of the battery based on the self-heating effect of the battery and the natural heat dissipation effect of the battery is calculated, and the thermal management characteristic parameter is controlled according to the temperature change trend.

[0008] In an embodiment of the present application, when the thermal management mode is a charging and heating mode, the thermal management characteristic parameter is controlled according to the temperature change trend, including: If the temperature change trend is less than zero, the thermal management system TMS operates at a first heating power and a first cooling water pump flow to make the temperature change trend of the battery zero, achieving temperature maintenance; If the temperature change trend is greater than or equal to zero, the thermal management system TMS is temporarily not started.

[0009] In an embodiment of the present application, when the thermal management mode is a charging and cooling mode, the thermal management characteristic parameter is controlled according to the temperature change trend, including: If the temperature change trend is greater than zero, the thermal management system TMS operates at a first cooling power and a second cooling water pump flow to make the temperature change trend of the battery zero, achieving temperature maintenance; If the temperature change trend of the battery is less than or equal to zero, the thermal management system TMS is temporarily not started.

[0010] In an embodiment of the present application, the current working condition thermal management characteristic parameter is controlled according to the working state of the battery management system BMS and the thermal management mode, including: When the working state of the battery management system BMS is a fast charging state; If the thermal management mode is a pure heating mode, the thermal management system TMS operates at a maximum heating power and a maximum cooling water pump flow until the battery temperature reaches a first target temperature within a second time; If the thermal management mode is a charging and heating mode or a charging and cooling mode, the temperature change trend of the battery based on the self-heating effect of the battery and the natural heat dissipation effect of the battery is calculated, and the thermal management characteristic parameter is controlled according to the temperature change trend. determining a current state point m(x0, y0) corresponding to a current battery state of charge SOC and a battery temperature based on a battery fast charging MAP, wherein x0 represents an SOC state and y0 represents a temperature state; obtaining a third time required for a battery state of charge SOC to change from a current state x0 to a next state window (x0+1); calculating a derivative of a battery charging rate with respect to temperature at the next state window (x0+1) ; controlling the thermal management characteristic parameter according to the derivative and the third time.

[0011] In an embodiment of the present application, when the thermal management mode is a charging and heating mode, the controlling the thermal management characteristic parameter according to the derivative and the third time includes: if the derivative is greater than 0, it is determined that the battery is in a temperature-increasing charging window, and the charging rate increases with the temperature; and the thermal management system TMS heats the battery according to the value of the partial derivative; if the derivative is less than 0, it is determined that the battery is in a balanced charging window, and the charging rate reaches a maximum value at the current temperature; and the thermal management system TMS operates at a second heating power and a third cooling water pump flow rate to keep the battery temperature stable within the third time.

[0012] In an embodiment of the present application, when the derivative , the method includes: calculating a rate of change of the derivative with respect to time ; if the rate of change , it is determined that the battery is in an accelerated charging window, and the growth rate of the charging rate increases with the temperature; and the thermal management system TMS operates at a maximum heating power and a maximum cooling water pump flow rate; if the rate of change , it is determined that the battery is in a decelerated charging window, and the growth rate of the charging rate decreases with the temperature; and the thermal management system TMS operates at a third heating power and a fourth cooling water pump flow rate to make the change amount of the battery temperature reach an expected temperature rise value within the third time.

[0013] In an embodiment of the present application, when the thermal management mode is a charging and cooling mode, the controlling the thermal management characteristic parameter according to the derivative and the third time includes: if the derivative If the battery is in a cooling charging window, the charging rate increases as the temperature decreases, and the thermal management system (TMS) cools the battery based on the value of the partial derivative.

[0014] In one embodiment of the present invention, in When, the method includes: Calculate the rate of change of the derivative with time. ; If the rate of change If the temperature decreases, the battery is determined to be in an accelerated charging window, and the rate of increase of the charging rate increases as the temperature decreases; the thermal management system (TMS) operates at maximum cooling power and maximum cooling water pump flow rate. If the rate of change If the battery is in a slow-down charging window, the rate of increase of the charging rate decreases as the temperature decreases; the control thermal management system TMS operates with the second cooling power and the fifth cooling water pump flow rate, so that the change in battery temperature reaches the expected temperature drop value in the third time period.

[0015] In one embodiment of the present invention, determining the corresponding thermal management mode based on the battery temperature includes: The thermal management mode of the corresponding battery is determined based on the relationship between the current battery temperature and the preset temperature threshold. The preset temperature threshold includes a pure heating threshold temperature, a charging allowable threshold temperature, and a charging high-temperature cooling threshold temperature. Among them, the pure heating threshold temperature < the charging allowable threshold temperature < the charging high-temperature cooling threshold temperature. If the current battery temperature is less than the pure heating threshold temperature, then the thermal management mode is determined to be the pure heating mode; If the pure heating threshold temperature is less than or equal to the current battery temperature and less than or equal to the charging allowable threshold temperature, then the thermal management mode is determined to be the simultaneous charging and heating mode. If the charging allowable threshold temperature is less than the current battery temperature and less than the charging high temperature cooling threshold temperature, then the thermal management mode is determined to be the pure charging mode. If the current battery temperature is greater than or equal to the high-temperature cooling threshold temperature during charging, then the thermal management mode is determined to be the simultaneous charging and cooling mode.

[0016] This application provides a power battery thermal management device, the power battery thermal management device comprising: The status recognition module is used to identify the working status of the vehicle's battery management system (BMS). The parameter acquisition module is used to acquire the battery temperature and current thermal management characteristic parameters of the battery. The mode determination module is used to determine the corresponding thermal management mode based on the battery temperature. The parameter control module is used to control the thermal management characteristic parameters under the current operating conditions according to the working status of the battery management system (BMS) and the thermal management mode.

[0017] The application provides a power battery thermal management device, comprising: one or more processors; and one or more machine-readable media having instructions stored thereon that, when executed by the one or more processors, cause the device to perform the power battery thermal management method.

[0018] The application provides a machine-readable medium having instructions stored thereon that, when executed by one or more processors, cause the processors to perform the power battery thermal management method.

[0019] The application has the following advantages: The application provides a power battery thermal management method, comprising: identifying the working state of a vehicle battery management system (BMS); obtaining the battery temperature and the current working condition thermal management characteristic parameter of a battery; determining the corresponding thermal management mode according to the battery temperature; and controlling the current working condition thermal management characteristic parameter according to the working state of the battery management system (BMS) and the thermal management mode. The application establishes a differentiated thermal management mode by dynamically identifying the working state of the battery management system and the battery temperature parameter, realizes precise temperature control, and has the advantages of improving the energy efficiency ratio of the thermal management system and optimizing the charging efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and serve to explain the principles of the application. It is clear that the drawings in the following description are only some embodiments of the application, and other drawings can be obtained from these drawings without creative labor for those skilled in the art.

[0021] In the drawings: Figure 1 A flowchart of a power battery thermal management method according to an embodiment of the application; Figure 2 A flowchart of controlling the current working condition thermal management characteristic parameter according to an embodiment of the application; Figure 3 A flowchart of controlling the thermal management characteristic parameter according to the temperature change trend according to an embodiment of the application; Figure 4 A flowchart of controlling the thermal management characteristic parameter according to the temperature change trend according to an embodiment of the application; Figure 5 A flowchart of controlling the current working condition thermal management characteristic parameter according to an embodiment of the application; Figure 6 A schematic diagram of a fast charging MAP according to an embodiment of the application; Figure 7 the derivative and the third time controlling the thermal management characteristic parameter; Figure 8 the flowchart for controlling the thermal management characteristic parameter at ; Figure 9 the flowchart for controlling the thermal management characteristic parameter at ; Figure 10 the flowchart for determining the thermal management mode according to the battery temperature; Figure 11 a schematic diagram of a power battery thermal management device according to an embodiment of the present application; Figure 12 a structural schematic diagram of a computer system suitable for implementing the memory according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail hereinafter with specific reference to the attached drawings and embodiments, but the present application can be implemented or applied in other different embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0023] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present application, and the drawings only show the components related to the present application, not the number, shape and size of the components when actually implemented. The shape, number and proportion of each component can be randomly changed when actually implemented, and the layout form of the components can be more complex.

[0024] In the following description, a large number of details are discussed to provide a more thorough explanation of the embodiments of the present application, however, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details, and in other embodiments, the known structures and devices are shown in the form of block diagrams instead of details, to avoid making the embodiments of the present application difficult to understand.

[0025] Please refer to Figure 1 , Figure 1 a flowchart of a power battery thermal management method according to an embodiment of the present application. In Figure 1 , the power battery thermal management method comprises: Step S110, identify the working state of the whole vehicle battery management system BMS; Step S120, obtain the battery temperature and the current working condition thermal management characteristic parameter of the battery; Step S130, determine the corresponding thermal management mode according to the battery temperature; Wherein, in the pure heating mode, the battery temperature is too low to allow charging; in the charging and heating mode, the battery temperature is low, allowing charging; in the pure charging mode, the battery temperature is suitable, and no further heating is needed; in the charging and cooling mode, the battery temperature is high, allowing charging.

[0026] Step S140, control the current working condition thermal management characteristic parameter according to the working state of the battery management system BMS and the thermal management mode.

[0027] The application dynamically identifies the working state of the battery management system and the battery temperature parameter, establishes a differentiated thermal management mode, realizes precise temperature control, and has the advantages of improving the energy efficiency ratio of the thermal management system and optimizing the charging efficiency.

[0028] The steps in the above scheme are described in detail as follows.

[0029] In step S110, the working state of the whole vehicle battery management system BMS is identified, and the working state includes slow charging state and fast charging state.

[0030] Wherein, the working state can be determined by analyzing the communication protocol of the battery management system BMS (Battery management system, BMS), which is used to distinguish the different thermal management requirements of slow charging and fast charging.

[0031] In step S120, the battery temperature and the current working condition thermal management characteristic parameter of the battery are obtained; Wherein, the battery temperature can be collected by the temperature sensor arranged in the battery module, and the temperature sensor can adopt NTC (Positive Temperature Coefficient thermistor) thermistor. The thermal management characteristic parameters include: heating power, cooling power, cooling water pump flow.

[0032] In step S130, the corresponding thermal management mode is determined according to the battery temperature; the thermal management mode includes pure heating mode, charging and heating mode, pure charging mode and charging and cooling mode; In the pure heating mode, the battery temperature is too low, only the battery is heated without charging; in the charging and heating mode, the battery temperature is low, charging is allowed and heating can be synchronized during charging; in the pure charging mode, the battery temperature is suitable, only charging is performed without heating the battery; in the charging and cooling mode, the battery temperature is high, charging is allowed, and the battery is cooled synchronously during charging.

[0033] Please refer to Figure 2 , Figure 2 The flow chart of controlling the current working condition thermal management characteristic parameter is an embodiment of the present application. In Figure 2 , the current working condition thermal management characteristic parameter is controlled according to the working state of the battery management system BMS and the thermal management mode, including: Step S210, when the working state of the battery management system BMS is a slow charging state, if the thermal management mode is a pure heating mode, the thermal management system TMS heats the battery with maximum heating power and maximum cooling water pump flow until the battery temperature reaches a first target temperature within a first time. Step S220, if the thermal management mode is a charging and heating mode or a charging and cooling mode, the temperature change trend of the battery based on the self-heating effect of the battery cell and the natural heat dissipation effect of the battery is calculated, and the thermal management characteristic parameter is controlled according to the temperature change trend.

[0034] Specifically, in the slow charging state, when the battery management system BMS detects that the battery temperature is too low, an instruction to enter the pure heating mode is issued, and the thermal management system TMS responds to the instruction of the battery management system BMS to enter the pure heating mode, controls the heater to run at maximum heating power, and controls the cooling water pump to run at maximum cooling water pump flow, rapidly heats the battery through forced circulation of high-temperature cooling liquid until the battery temperature reaches a first target temperature within a first time, wherein the first target temperature is the end threshold of the pure heating mode. When the battery temperature is in a critical low temperature interval, the charging and heating mode is entered, the temperature change trend of the battery is determined by real-time monitoring of the self-heating effect of the battery cell and the natural heat dissipation effect of the battery (without heating power and cooling water pump flow), and the heating power and the cooling water pump flow are dynamically adjusted according to the temperature change trend to control the battery temperature. When the battery temperature approaches a high temperature threshold, the charging and cooling mode is switched to, the temperature change trend of the interaction of the self-heating effect of the battery cell and the natural heat dissipation effect of the battery is analyzed, and the heating power and the cooling water pump flow are dynamically adjusted according to the temperature change trend to control the battery temperature.

[0035] It should be noted that the first time can also be understood as the time when the thermal management system TMS operates at the maximum heating power and the maximum cooling water pump flow. The first time can be obtained by a pre-established correlation between the battery temperature, the requested heating power, the cooling water pump flow and the time. For example, after obtaining the target battery temperature, the requested heating power and the cooling water pump flow, the three parameters are substituted into the correlation as input parameters to output the time when the battery temperature reaches the target temperature.

[0036] The application shortens the user waiting time by using the maximum power to quickly heat up in the pure heating mode. In the charging and heating mode or the charging and cooling mode, the temperature change trend is used as the control core to realize accurate on-demand control, so that the battery temperature is stabilized in the optimal charging efficiency interval, and the charging efficiency is improved.

[0037] Please refer to Figure 3 , Figure 3 The flowchart of controlling the thermal management characteristic parameters according to the temperature change trend is an embodiment of the application. In Figure 3 , when the thermal management mode is the charging and heating mode, the controlling the thermal management characteristic parameters according to the temperature change trend comprises: Step S310, if the temperature change trend is less than zero, the thermal management system TMS operates at the first heating power and the first cooling water pump flow, so that the temperature change trend of the battery is zero, and temperature maintenance is realized. Step S320, if the temperature change trend is greater than or equal to zero, the thermal management system TMS is temporarily not started.

[0038] It should be noted that the temperature change trend less than zero indicates that the battery temperature decreases, the temperature change trend greater than zero indicates that the battery temperature increases, and the temperature change trend equal to zero indicates that the battery temperature remains constant and does not change.

[0039] Specifically, when the battery temperature is in the critical low temperature interval, the charging and heating mode is entered, the change trend of the battery temperature is determined by real-time monitoring of the self-heating effect of the battery and the natural heat dissipation effect of the battery (without heating power and cooling water pump flow), and when the temperature change trend dT / dt is less than zero, the heating power and the cooling water pump flow are dynamically adjusted, so that the thermal management system TMS operates at the first heating power and the first cooling water pump flow, so that the battery temperature remains stable during charging. When the temperature change trend dT / dt of the battery is greater than or equal to zero, the thermal management system TMS is temporarily not started.

[0040] The application determines the control strategy according to the size of the temperature change trend, and only when the temperature change trend is greater than zero, the thermal management system TMS is operated at the first cooling power and the second cooling water pump flow to maintain the battery temperature balance, avoiding unnecessary frequent start and stop of the thermal management system TMS and energy consumption.

[0041] Please refer to Figure 4 , Figure 4 The flow chart for controlling the thermal management characteristic parameter according to the temperature change trend in an embodiment of the application. Figure 4 In the thermal management mode is the charging and cooling mode, the control of the thermal management characteristic parameter according to the temperature change trend comprises: Step S410, if the temperature change trend is greater than zero, the thermal management system TMS is operated at the first cooling power and the second cooling water pump flow to make the temperature change trend of the battery zero, realizing temperature maintenance. Step S420, if the temperature change trend of the battery is less than or equal to zero, the thermal management system TMS is not started temporarily.

[0042] Specifically, when the battery temperature approaches the high temperature threshold, the charging and cooling mode is switched to, the temperature change trend of the interaction of the self-heating effect of the battery and the natural heat dissipation effect of the battery is analyzed, and when the temperature change trend dT / dt is greater than zero, the thermal management system TMS is controlled to operate at the first cooling power and the second cooling water pump flow to make the temperature change trend of the battery zero, realizing temperature maintenance; if the temperature change trend dT / dt is less than or equal to zero, the thermal management system TMS is not started temporarily.

[0043] The application determines the control strategy according to the size of the temperature change trend, and only when the temperature change trend is greater than zero, the thermal management system TMS is operated at the first cooling power and the second cooling water pump flow to maintain the battery temperature balance, avoiding unnecessary frequent start and stop of the thermal management system TMS and energy consumption.

[0044] Please refer to Figure 5 , Figure 5 The flow chart for controlling the current working condition thermal management characteristic parameter in an embodiment of the application. Figure 5 In the thermal management mode is the charging and cooling mode, the control of the thermal management characteristic parameter according to the temperature change trend comprises: Step S510, when the working state of the battery management system BMS is the fast charging state, if the thermal management mode is the pure heating mode, the thermal management system TMS is operated at the maximum heating power and the maximum cooling water pump flow until the battery temperature reaches the first target temperature within the second time. It should be noted that the second time can also be understood as the time during which the thermal management system TMS operates at maximum heating power and maximum cooling water pump flow. The second time can be obtained by a pre-established correlation between the battery temperature, the requested heating power, the cooling water pump flow and the time. For example, after obtaining the target battery temperature, the requested heating power and the cooling water pump flow, the three parameters are substituted into the correlation as input parameters to output the time for the battery temperature to reach the target temperature.

[0045] Step S520, if the thermal management mode is the charging-while-heating mode or the charging-while-cooling mode, then: Step S5201, based on the fast charging MAP of the battery, determining the current state bit m(x0, y0) corresponding to the current battery state of charge SOC and the battery temperature, wherein x0 represents the SOC state and y0 represents the temperature state; wherein the fast charging map is as shown in Figure 6 ; the uppermost horizontal coordinate is SOC (%), the left vertical coordinate is the battery temperature (℃), and the state bit m(x0, y0) is determined by its position coordinate. In the map, (x0+1) can be regarded as the SOC moving to the right (SOC increasing), and (y0+1) can be regarded as the temperature moving downward (temperature increasing).

[0046] Step S5202, obtaining a third time required for the battery state of charge SOC to change from the current state x0 to the next state window (x0+1); Step S5203, calculating the derivative of the battery charging rate to the temperature in the next state window (x0+1) ; Step S5204, controlling the thermal management characteristic parameter according to the derivative and the third time.

[0047] Specifically, in the fast charging state, when the thermal management mode is the charging-while-heating or the charging-while-cooling, first, the fast charging MAP (such as Figure 6The state bit corresponding to the current battery state of charge SOC and battery temperature is determined (as shown in the figure). For example, if the current SOC is 30% and the temperature is 10℃, the corresponding state bit m(30%, 10℃) is determined. Then, the estimated time required for the battery state of charge SOC to change from the current state to the next state window is calculated, for example, it may take 5 minutes to change from 30% to 35%. At the same time, the partial derivative of the charging rate with respect to the temperature is calculated according to the charging rate-temperature relationship corresponding to the next state window. For example, if the charging rate is allowed to increase by 0.1C per 1℃ increase in temperature in the next state window, the partial derivative is 0.1C / ℃. According to the derivative value and the estimated time, the heating power or cooling power is dynamically adjusted. For example, if the derivative indicates that the temperature increase can significantly increase the charging rate, the heating power is increased to accelerate the temperature rise; if the derivative tends to zero, the current temperature is maintained to stabilize the charging efficiency.

[0048] By querying the MAP diagram and calculating the derivative of the charging rate with respect to the temperature, the present application can predict the characteristics of the charging window that the battery is about to enter, thereby adjusting the thermal management strategy in advance to prepare for subsequent fast charging and maximize the use of the battery's fast charging capability.

[0049] Please refer to Figure 7 , Figure 7 for an embodiment of the present application. The flowchart of the present application for controlling the thermal management characteristic parameter according to the derivative and the third time. In Figure 7 , when the thermal management mode is the charging-while-heating mode, the thermal management characteristic parameter is controlled according to the derivative and the third time, including: Step S710, if the derivative , it is determined that the battery is in a temperature-increasing charging window, in which the charging rate increases with the temperature increase; the thermal management system TMS heats the battery according to the value of the partial derivative; Step S720, if the derivative , it is determined that the battery is in a balanced charging window, in which the charging rate reaches a maximum value at the current temperature; the thermal management system TMS operates at a second heating power and a third cooling water pump flow rate to keep the battery temperature stable within the third time.

[0050] The temperature-increasing charging window refers to the interval in which the battery temperature is in the range where the charging rate increases with the temperature increase. The balanced charging window refers to the temperature at which the battery state of charge SOC reaches the temperature corresponding to the charging rate, and at this temperature, the battery charging rate is maximum.

[0051] Specifically, when the battery is in fast charging state and the thermal management mode is heating while charging, first, the state point corresponding to the current battery state of charge SOC and temperature is determined based on the fast charging MAP, and the time required for the battery to enter the next SOC window is predicted. By calculating the partial derivative of the charging rate to the temperature , it is determined whether the battery is in the temperature rising charging window or the balance charging window. If the derivative is greater than zero, it indicates that the battery is in the temperature rising charging window, and the temperature rise will increase the charging rate. At this time, the thermal management system TMS heats the battery according to the value of the partial derivative. If the derivative is equal to zero, it indicates that the battery is in the balance charging window, that is, the current temperature makes the charging rate reach the maximum value. At this time, the thermal management system switches to the second heating power and the third water pump flow, so that the battery maintains the temperature stable within the third time.

[0052] The present application distinguishes the temperature rising charging window and the balance charging window by the size of the derivative, raises the battery temperature to the optimal charging efficiency interval in the charging window, and maintains the temperature stable to keep the maximum charging rate in the balance charging window, thereby effectively shortening the charging time and reducing the energy consumption of the thermal management system.

[0053] Please refer to Figure 8 , Figure 8 is the flow chart of controlling the thermal management characteristic parameters of an embodiment of the present application. In , the method comprises: Figure 8 In , the method comprises: Step S810, calculating the change rate of the derivative with time ; Step S820, if , it is determined that the battery is in the accelerated charging window, wherein the growth rate of the charging rate increases with the temperature rise, and the thermal management system TMS operates at the maximum heating power and the maximum cooling water pump flow; Step S830, if , it is determined that the battery is in the decelerated charging window, wherein the growth rate of the charging rate decreases with the temperature rise, and the thermal management system TMS operates at the third heating power and the fourth cooling water pump flow, so that the change amount of the battery temperature reaches the expected temperature rise value within the third time t3.

[0054] Wherein, the accelerated charging window refers to the working condition interval in which the charging rate grows with the temperature rise; the decelerated charging window refers to the working condition interval in which the charging rate decreases with the temperature rise.

[0055] Specifically, in the fast charging state, when the battery is in the heating while charging mode, by monitoring the change rate of the partial derivative of the charging rate to the temperature with time , the charging process is identified. When the change rate is detected When the derivative is greater than zero, it indicates that the battery enters the accelerated charging window, at which time the thermal management system TMS is automatically switched to the maximum heating power and maximum cooling water pump flow combination operation to quickly raise the battery temperature to match the growth demand of the charging rate. Conversely, when the derivative is less than zero, it indicates that the battery enters the decelerated charging window, at which time the system is switched to a low-power heating mode and matched with a medium water pump flow, and the thermal management system TMS operates at a third heating power and a fourth cooling water pump flow, so that the change amount of the battery temperature reaches the expected temperature rise value within the third time t3, and the temperature rise amplitude is accurately controlled. The expected temperature rise value is the difference between the current battery temperature and the battery temperature of the next window.

[0056] The application distinguishes the accelerated charging window and the decelerated charging window by the derivative, maximizes the lifting amplitude of the charging speed in the accelerated charging window, and adopts moderate heating in the decelerated charging window to balance between the speed lifting and energy consumption, thereby avoiding energy loss caused by excessive heating.

[0057] In an embodiment, when the thermal management mode is the charging-while-cooling mode, the derivative and the third time control the thermal management characteristic parameters, including: If , it is determined that the battery is in the temperature-reducing charging window, in which the charging rate increases with the decrease of the temperature, and the thermal management system TMS cools the battery according to the value of the partial derivative.

[0058] The temperature-reducing charging window refers to the interval in which the battery temperature needs to be actively cooled, and at this time the charging rate increases with the decrease of the temperature.

[0059] Specifically, in the fast charging process, when it is detected that the battery temperature exceeds the high-temperature cooling threshold for charging, the system enters the charging-while-cooling mode. At this time, by analyzing the fast charging MAP graph, the charging rate corresponding to the current state of charge and temperature is obtained, and the partial derivative of the charging rate with respect to the temperature is calculated. If , it indicates that the charging rate increases with the decrease of the temperature at the current temperature, at which time it is determined that the battery enters the temperature-reducing charging window. The thermal management system TMS cools the battery according to the value of the partial derivative.

[0060] The application identifies the temperature-reducing charging window by analyzing the derivative of the charging rate with respect to the temperature in the fast charging MAP graph, and matches the cooling power and water pump flow according to the temperature-reducing charging window, thereby ensuring the charging efficiency while reducing the power consumption of the thermal management system.

[0061] Please refer to Figure 9 , Figure 9 for the charging-while-cooling mode of an embodiment of the application ​A flow chart for controlling the thermal management characteristic parameter over time. In Figure 9 In , the method comprises: Step S910, calculating the rate of change of the derivative over time ; Step S920, if , determining that the battery is in an accelerated charging window in which the rate of increase of the charging rate increases as the temperature decreases; the thermal management system TMS operates at maximum heating power and maximum cooling water pump flow rate; Step S930, if , determining that the battery is in a decelerated charging window in which the rate of increase of the charging rate decreases as the temperature decreases; the control thermal management system TMS operates at a second cooling power and a fifth cooling water pump flow rate, so that the amount of change in the battery temperature reaches an expected temperature drop value within the third time; the expected temperature drop value is the difference between the battery temperature at the current time and the battery temperature of the next window.

[0062] wherein the accelerated charging window refers to a state in which the rate of increase of the charging rate increases as the temperature decreases; and the decelerated charging window refers to a state in which the rate of increase of the charging rate decreases as the temperature decreases.

[0063] Specifically, when the battery is in the charging and cooling mode and the charging rate increases as the temperature decreases, the type of charging window in which the battery is located is dynamically identified by real-time calculation of the rate of change of the derivative over time . If the rate of change , it indicates that the battery is in an accelerated charging window, in which the charging rate presents an accelerated growth trend as the temperature decreases, and the thermal management system TMS operates in combination of maximum cooling power and maximum cooling water pump flow rate. If the rate of change , it indicates that the battery enters a decelerated charging window, in which the charging rate growth rate decays as the temperature decreases, and the thermal management system TMS switches to a combination of a second cooling power and a fifth cooling water pump flow rate, so as to increase the cooling power to make the battery temperature reach an expected temperature drop value within a third time, thereby avoiding the decrease of charging efficiency caused by excessive cooling.

[0064] The present application distinguishes whether the battery is in an accelerated charging window or a decelerated charging window through the rate of change of the partial derivative over time, controls the battery temperature of the TMS at the maximum cooling power in the accelerated charging window, and adjusts the battery state to the best in the shortest time. In the decelerated charging window, the TMS operates at a lower second cooling power, avoids energy waste, and realizes the best balance between charging speed and system energy consumption.

[0065] Referring to Figure 10 , Figure 10 is a flow chart for determining the thermal management mode according to the battery temperature in an embodiment of the present application.Figure 10 In some embodiments, the determining the corresponding thermal management mode according to the battery temperature comprises: In step S1010, the thermal management mode of the battery is determined according to the relationship between the current battery temperature and the preset temperature threshold; the preset temperature threshold includes a pure heating threshold temperature, a charging allowable threshold temperature and a charging high-temperature cooling threshold temperature; wherein the pure heating threshold temperature < the charging allowable threshold temperature < the charging high-temperature cooling threshold temperature. In step S1020, if the current battery temperature < the pure heating threshold temperature, the thermal management mode is determined as the pure heating mode. In step S1030, if the pure heating threshold temperature ≤ the current battery temperature ≤ the charging allowable threshold temperature, the thermal management mode is determined as the charging and heating mode. In step S1040, if the charging allowable threshold temperature < the current battery temperature < the charging high-temperature cooling threshold temperature, the thermal management mode is determined as the pure charging mode. In step S1050, if the current battery temperature ≥ the charging high-temperature cooling threshold temperature, the thermal management mode is determined as the charging and cooling mode.

[0066] In some embodiments, the preset temperature threshold refers to a temperature critical value preset for dividing different thermal management modes, for example, the pure heating threshold temperature can be set to -20℃, the charging allowable threshold temperature is set to 5℃, and the charging high-temperature cooling threshold temperature is set to 40℃.

[0067] Specifically, after the battery temperature detection module obtains the current temperature, the control unit compares the temperature data with the preset threshold. For example, when the battery temperature is detected to be -20℃, since it is lower than the pure heating threshold temperature, the pure heating mode is preferentially started, and when the temperature rises to above 5℃, the charging and heating mode is switched. When the temperature is 20℃, the system enters the pure charging mode, at which time the thermal management system stops working to reduce energy consumption. When the temperature exceeds 40℃, the system immediately starts the charging and cooling mode, and the temperature is controlled within a safe range through liquid cooling circulation.

[0068] The present application clearly divides the thermal management requirements of the battery into four modes by setting three key temperature thresholds, ensuring that the control strategy can seamlessly cover the entire working temperature range of the battery from extremely low temperature to high temperature, and ensuring the applicability in various environments.

[0069] Please refer to Figure 11 , Figure 11 A schematic diagram of a power battery thermal management device according to an embodiment of the present application. In Figure 11 In some embodiments, the power battery thermal management device comprises: The state recognition module 1110 is configured to recognize the working state of the battery management system (BMS) of the whole vehicle, and the working state includes a slow charging state and a fast charging state. obtain a battery temperature and a current operating thermal management characteristic parameter of the battery; determine a corresponding thermal management mode according to the battery temperature; the thermal management mode includes a pure heating mode, a charging and heating mode, a pure charging mode, and a charging and cooling mode; control the current operating thermal management characteristic parameter according to a working state of the battery management system BMS and the thermal management mode.

[0070] It should be noted that the power battery thermal management device provided in the above embodiment and the power battery thermal management method provided in the above embodiment belong to the same concept, and the specific manner in which each module and unit performs operations has been described in detail in the method embodiment, which will not be repeated here. The power battery thermal management device provided in the above embodiment can be used in actual application, and the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above, and this is not limited herein.

[0071] Embodiments of the present application also provide a power battery thermal management device, comprising: one or more processors; and a memory for storing one or more programs, when the one or more programs are executed by the one or more processors, the memory implements the power battery thermal management method in the above embodiments.

[0072] Embodiments of the present application also provide one or more machine readable media having instructions stored thereon, when executed by one or more processors, cause the processors to perform the power battery thermal management method in the above embodiments.

[0073] Figure 12 The structure schematic diagram of a computer system of the memory suitable for realizing the embodiments of the present application is shown. It should be noted that, Figure 12 The computer system of the memory shown is only an example, and should not bring any limitation to the functions and use range of the embodiments of the present application.

[0074] As Figure 12As shown, the computer system 1200 includes a central processing unit (CPU) 1201 which can perform various appropriate actions and processes in accordance with a program stored in a read-only memory (ROM) 1202 or a program loaded from a storage section into a random access memory (RAM) 1203, such as executing the method in the above-described embodiments. In the RAM, various programs and data required for system operation are also stored. The CPU 1201, the ROM 1202, and the RAM 1203 are connected to each other through a bus 1204. An input / output (I / O) interface 1205 is also connected to the bus 1204.

[0075] Connected to the I / O interface 1105 are an input section 1206 including a keyboard, a mouse, etc.; an output section 1207 including a display device such as a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1208 including a hard disk, etc.; and a communication section 1209 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 1209 performs communication processing via a network such as the Internet. A drive 1210 is also connected to the I / O interface 1205 as necessary. A removable recording medium 1211 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is attached to the drive 1210 as necessary, so that a computer program read therefrom is installed into the storage section 1208 as necessary.

[0076] In particular, according to the embodiments of the present application, the processes described above with reference to the flowcharts can be implemented as a computer software program. For example, the embodiments of the present application include a computer program product including a computer program carried on a computer-readable medium, the computer program containing a computer program for executing the power battery thermal management method of the aforementioned embodiments. In such embodiments, the computer program can be downloaded and installed from a network by the communication section, and / or installed from the removable recording medium 1211. When the computer program is executed by the central processing unit (CPU) 1201, various functions defined in the system of the present application are performed.

[0077] It should be noted that the computer-readable medium in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the two. The computer-readable storage medium may, for example, be an electrical, magnetic, optical, electromagnetic, infrared or semiconductor system, device or apparatus, or any combination of the above. More specific examples of the computer-readable storage medium can include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) 1203, a read-only memory (ROM) 1202, an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (Compact Disc Read-Only Memory, CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this application, the computer-readable signal medium can include a data signal carried in a baseband or as a part of a carrier wave, which carries computer-readable computer programs. Such a propagated data signal can take on various forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, which can send, propagate or transmit programs for use by or in connection with an instruction execution system, apparatus or device. The computer programs contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to wireless, wired, or the like, or any suitable combination of the above.

[0078] The flowcharts and block diagrams in the drawings illustrate the possible implementation architectures, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. Each block in the flowcharts or block diagrams can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions indicated in the blocks can also occur in a different order from that indicated in the drawings. For example, two blocks indicated in succession can actually be executed substantially in parallel, and sometimes in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, or a combination of blocks in the flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0079] The units described in the embodiments of the present application can be implemented in the form of software, or can be implemented in the form of hardware, and the described units can also be arranged in a processor. In some cases, the names of the units do not constitute a limitation on the units themselves.

[0080] Another aspect of the present application also provides a computer readable storage medium, which stores a computer program. When the computer program is executed by a processor of a computer, the computer executes the power battery thermal management method as described above. The computer readable storage medium can be included in the memory described in the above embodiments, or can exist separately and not be assembled into the memory.

[0081] Another aspect of the present application also provides a computer program product or a computer program, which includes computer instructions stored in a computer readable storage medium. A processor of a computer device reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions, so that the computer device executes the power battery thermal management method provided in each of the above embodiments.

[0082] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A method of thermal management of a power battery, characterized in that, The power battery thermal management method comprises: identifying a working state of a vehicle battery management system (BMS); obtaining a battery temperature and a current working condition thermal management characteristic parameter of the battery; determining a corresponding thermal management mode according to the battery temperature; controlling the current working condition thermal management characteristic parameter according to the working state of the battery management system (BMS) and the thermal management mode.

2. The power cell thermal management method of claim 1, wherein, The controlling the current working condition thermal management characteristic parameter according to the working state of the battery management system (BMS) and the thermal management mode comprises: when the working state of the battery management system (BMS) is a slow charging state; if the thermal management mode is a pure heating mode, the thermal management system (TMS) heats the battery at a maximum heating power and a maximum cooling water pump flow until the battery temperature reaches a first target temperature within a first time; if the thermal management mode is a charging-while-heating mode or a charging-while-cooling mode, a temperature change trend of the battery based on a self-heating effect of the battery and a natural heat dissipation effect of the battery is calculated, and the thermal management characteristic parameter is controlled according to the temperature change trend.

3. The power cell thermal management method of claim 2, wherein, When the thermal management mode is the charging-while-heating mode, the controlling the thermal management characteristic parameter according to the temperature change trend comprises: if the temperature change trend is less than zero, the thermal management system (TMS) operates at a first heating power and a first cooling water pump flow to make the temperature change trend of the battery zero, achieving temperature maintenance; if the temperature change trend is greater than or equal to zero, the thermal management system (TMS) is temporarily not started.

4. The power cell thermal management method of claim 2, wherein, When the thermal management mode is the charging-while-cooling mode, the controlling the thermal management characteristic parameter according to the temperature change trend comprises: if the temperature change trend is greater than zero, the thermal management system (TMS) operates at a first cooling power and a second cooling water pump flow to make the temperature change trend of the battery zero, achieving temperature maintenance; if the temperature change trend of the battery is less than or equal to zero, the thermal management system (TMS) is temporarily not started.

5. The power cell thermal management method of claim 2, wherein, The controlling the current working condition thermal management characteristic parameter according to the working state of the battery management system (BMS) and the thermal management mode comprises: when the working state of the battery management system (BMS) is a fast charging state; if the thermal management mode is a pure heating mode, the thermal management system (TMS) operates at a maximum heating power and a maximum cooling water pump flow until the battery temperature reaches a first target temperature within a second time; if the thermal management mode is a charging-while-heating mode or a charging-while-cooling mode, the following steps are performed: based on a fast charging map of the battery, a current state bit m(x0, y0) corresponding to a current battery state of charge (SOC) and a battery temperature is determined, wherein x0 represents an SOC state and y0 represents a temperature state; a third time required for the battery state of charge (SOC) to change from a current state x0 to a next state window (x0+1) is obtained; Compute the derivative of the battery charge rate with respect to temperature at the next state window (x0+1) ; According to the derivative and the third time control the thermal management characteristic parameter.

6. The power cell thermal management method of claim 5, wherein, when the thermal management mode is the charging-while-heating mode, the controlling the thermal management characteristic parameter according to the derivative and the third time includes: if the derivative is greater than, it is determined that the battery is in a warm-up charging window, in which the charging rate increases with increasing temperature; the thermal management system TMS heats the battery in dependence on the value of the partial derivative. If the derivative is greater than zero, it is determined that the battery is in the charging window, and the charging rate reaches a maximum value at the current temperature; the thermal management system TMS operates at a second heating power and a third cooling water pump flow rate to keep the battery temperature stable within the third time.

7. The power cell thermal management method of claim 6, wherein, At said derivative heating the battery in accordance with the value of the partial derivative comprises: computing a rate of change of the derivative over time ; if the rate of change then the battery is determined to be in an accelerated charging window, the rate of increase of the charge rate increases with temperature, and the thermal management system TMS operates at maximum heating power and maximum cooling water pump flow rate; if the rate of change then it is determined that the battery is in a reduced-rate charging window, in which the rate of increase of the charging rate decreases with increasing temperature, and the thermal management system TMS is operated at a third heating power and a fourth cooling water pump flow rate, such that the amount of change in the battery temperature reaches an expected temperature increase value within the third time.

8. The power cell thermal management method of claim 5, wherein, when the thermal management mode is the charging-while-cooling mode, the derivative and the third time control the thermal management characteristic parameter, comprising: if the derivative is positive, it is determined that the battery is in a cooling charging window, the charging rate increases with the decrease of temperature, and the thermal management system TMS cools the battery according to the value of the partial derivative.

9. The power cell thermal management method of claim 8, wherein, In case the value of the partial derivative is positive, the thermal management system TMS cools down the battery in dependence on the value of the partial derivative. computing a rate of change of the derivative over time ; if the rate of change then the battery is determined to be in an accelerated charging window, the rate of increase of the charge rate increases as the temperature decreases; the thermal management system TMS operates at maximum cooling power and maximum cooling water pump flow rate; if the rate of change then it is determined that the battery is in a reduced-rate charging window, in which the rate of increase of the charging rate decreases as the temperature decreases; the thermal management system TMS is controlled to operate at a second cooling power and a fifth cooling water pump flow rate, such that the amount of change in the battery temperature reaches an expected temperature drop value within the third time.

10. The power cell thermal management method of claim 1, wherein, The determining the corresponding thermal management mode according to the battery temperature comprises: According to the relationship between the current battery temperature and the preset temperature threshold, a heat management mode corresponding to the battery is determined; the preset temperature threshold includes a pure heating threshold temperature, a charging allowable threshold temperature, and a charging high-temperature cooling threshold temperature; wherein the pure heating threshold temperature < the charging allowable threshold temperature < the charging high-temperature cooling threshold temperature; If the current battery temperature < the pure heating threshold temperature, it is determined that the heat management mode is a pure heating mode; If the pure heating threshold temperature ≤ the current battery temperature ≤ the charging allowable threshold temperature, it is determined that the heat management mode is a charging and heating mode; If the charging allowable threshold temperature < the current battery temperature < the charging high-temperature cooling threshold temperature, it is determined that the heat management mode is a pure charging mode; If the current battery temperature ≥ the charging high-temperature cooling threshold temperature, it is determined that the heat management mode is a charging and cooling mode.

11. A power cell thermal management device, characterized by, The power battery heat management device comprises: a state recognition module for recognizing the working state of a battery management system (BMS) of a whole vehicle; a parameter acquisition module for acquiring the battery temperature and the current working condition heat management characteristic parameter of the battery; a mode determination module for determining the corresponding heat management mode according to the battery temperature; a parameter control module for controlling the current working condition heat management characteristic parameter according to the working state of the battery management system (BMS) and the heat management mode.

12. A power cell thermal management apparatus, characterized by, comprise: one or more processors; and one or more machine-readable media having instructions stored thereon that, when executed by the one or more processors, cause the device to perform the power battery heat management method as claimed in any one of claims 1-10.

13. A machine-readable medium, comprising: one or more machine-readable media having instructions stored thereon that, when executed by the one or more processors, cause the device to perform the power battery heat management method as claimed in any one of claims 1-10.

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