Slow-charging low-temperature heating control method and system and vehicle

Abstract

The invention relates to the technical field of charging, in particular to a slow-charging low-temperature heating control method and system and a vehicle. The method comprises the steps that after a whole vehicle enters a charging process, judgment is conducted according to the temperature of a battery module and a low-temperature heating threshold value; if the temperature of the battery module is less than or equal to the low-temperature heating threshold, the battery management system sends a heating mode request signal; the vehicle-mounted charger controls the high-voltage direct-current output current to be smaller than or equal to I1, collects the high-voltage direct-current output current in real time and sends the high-voltage direct-current output current to the battery management system, and meanwhile sends a signal that the maximum output current capacity of the charger is smaller than or equal to I1 to the battery management system; after the battery management system receives the high-voltage direct-current output current and the maximum output current capacity of the charger, the charging current of the battery module and the maximum output current capacity of the charger are compared with a heating mode starting current threshold value I2, and whether the heating mode is requested to exit or not is determined according to the comparison result. According to the invention, the battery can be heated at low temperature to accelerate charging, and the control strategy is relatively simple.

Description

Technical Field

[0001] The present invention relates to the field of charging technology, and in particular to a slow-charging and low-temperature heating control method, system, and vehicle. Background Art

[0002] With the booming new energy vehicle market and the increasing availability of charging infrastructure, more and more users are choosing to install home charging stations in their private parking spaces, providing a convenient way to recharge their electric vehicles. This not only makes daily driving more convenient, but also allows users to enjoy the economic benefits of peak and off-peak electricity prices.

[0003] However, new energy vehicles face a critical issue in practical use: the charging speed of power batteries is significantly affected by low temperatures. In low temperatures, the chemical reactions within the battery slow down, causing the charging speed to gradually decrease. This not only prolongs charging time but also seriously affects the user's charging experience.

[0004] Therefore, it is necessary to develop a slow charging and low temperature heating control method, system and vehicle. Summary of the Invention

[0005] The object of the present invention is to provide a slow charging and low temperature heating control method, system and vehicle, which can heat the battery at low temperatures to speed up charging, and the control strategy is relatively simple.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: In a first aspect, a slow charging and low temperature heating control method according to the present invention comprises the following steps: When the vehicle is plugged in and enters the charging process, the battery management system makes a judgment based on the battery module temperature and the low-temperature heating threshold; If the battery module temperature is less than or equal to the low-temperature heating threshold, the battery management system sends a heating mode request signal; After receiving the heating mode request signal, the on-board charger controls the high-voltage DC output current to be less than or equal to I1 and collects the high-voltage DC output current in real time and sends it to the battery management system. At the same time, it sends a signal indicating that the maximum output current capability of the charger is less than or equal to I1 to the battery management system; After receiving the high-voltage DC output current and the maximum output current capability of the charger, the battery management system compares the battery module charging current, the maximum output current capability of the charger with the heating mode start current threshold I2, and decides whether to request to exit the heating mode based on the comparison result; Among them, I2>I1, I1 is the minimum current output capacity value of the on-board charger at the current temperature, and I2 is the starting current threshold of the heating mode.

[0007] In one possible implementation, when both the charger's maximum output current capability and the battery module's charging current are less than or equal to I2, the battery management system controls the switch to disconnect and sends a switch-off signal to the onboard charger. By precisely controlling the timing of the switch disconnection, preparations are made for the subsequent stable heating power adjustment phase, ensuring that the heating process begins within a safe current range.

[0008] In one possible implementation, upon receiving a switch-off signal, the onboard charger controls the high-voltage DC output current to be less than or equal to I3, collects the high-voltage DC output current in real time, and sends it to the battery management system. Simultaneously, a signal indicating that the charger's maximum output current capability is less than or equal to I3 is sent to the battery management system for heating power level calculation. Here, I3 > I2, where I3 represents the current output capability of the onboard charger at the current temperature. This allows the onboard charger to adjust its output current appropriately based on its capabilities to accommodate heating requirements at varying temperatures.

[0009] In one possible implementation, the battery management system calculates the heating level based on the high-voltage DC output current and the charger's maximum output current capability, then controls the heating module to heat the battery module. During the heating process, the battery module temperature is collected in real time and reported to the battery management system. By accurately calculating the heating level, heating energy can be rationally allocated based on actual conditions, avoiding energy waste or insufficient heating. Real-time collection and reporting of battery module temperature enables the battery management system to keep abreast of heating progress and battery status, providing a basis for subsequent adjustment of control strategies based on temperature changes, ensuring that the heating process remains under control.

[0010] In a possible implementation, the battery management system compares the received battery module temperature with a low-temperature heating threshold. When the battery module temperature is less than or equal to the low-temperature heating threshold, the current heating state is maintained. When the battery module temperature is greater than the low-temperature heating threshold, the battery management system controls the switch to close and sends a switch-state closure signal to the onboard charger. The onboard charger controls the high-voltage DC output current to be less than or equal to I4, collects the high-voltage DC output current in real time, and sends it to the battery management system. Simultaneously, it sends a signal indicating that the charger's maximum output current capability is less than or equal to I4 to the battery management system. The battery management system dynamically calculates and allocates charging and heating power based on the high-voltage DC output current, the charger's maximum output current capability, and the battery module temperature, implementing simultaneous charging and heating until the low-temperature heating mode is exited. Where I4 > I3, and I4 represents the maximum current output capability of the onboard charger at the current temperature. When the battery module temperature is less than or equal to the low-temperature heating threshold, the heating state is maintained, ensuring continuous heating of the power battery in low-temperature environments until the appropriate temperature is reached. When the battery module temperature is greater than the low-temperature heating threshold, the switch is controlled to close and enter the simultaneous charging and heating mode, dynamically allocating charging and heating power based on various signals. This control method, which adjusts in real time according to temperature, can not only effectively increase the battery temperature, but also promptly switch to the parallel charging and heating mode when the temperature is suitable, thereby improving the overall energy replenishment efficiency. At the same time, dynamic power allocation ensures the stability and efficiency of the charging and heating process.

[0011] One possible implementation involves entering charging mode if the battery module temperature after charging is greater than the charging start temperature threshold. If the battery module temperature is greater than the low-temperature heating threshold but less than or equal to the charging start temperature threshold, the system directly enters a simultaneous charging and heating process until it exits heating mode, where the low-temperature heating threshold is less than the charging start temperature threshold. This clarifies the system's operating modes under different temperature conditions. If the battery module temperature after charging is greater than the charging start temperature threshold, the system directly enters charging mode, avoiding unnecessary heating and saving time and energy. If the battery module temperature is greater than the low-temperature heating threshold but less than or equal to the charging start temperature threshold, the system directly enters a simultaneous charging and heating process. This simplifies the control process, enabling the system to quickly respond to different temperature conditions and select the optimal operating mode based on actual conditions, improving the system's adaptability and efficiency.

[0012] In one possible implementation, if the battery module charging current and the charger's maximum output current capability are not both less than or equal to I2, indicating an anomaly, the battery management system requests that the heating mode be exited and a fault report be generated for troubleshooting. This mechanism promptly detects current anomalies, preventing damage to batteries, charging equipment, and other components, thereby ensuring system safety and stability. By promptly exiting heating mode and providing a fault notification, users or maintenance personnel can quickly identify the problem and implement appropriate remedial measures, mitigating potential risks.

[0013] In a second aspect, the present invention provides a slow-charging, low-temperature heating control system, comprising an on-board charger, a power battery, and a battery management system. The power battery comprises a battery module and a heating module, wherein the heating module is configured to heat the battery module. The on-board charger is connected to the battery module and the heating module respectively, and a switch is connected between the on-board charger and the battery module; The battery module and the heating module are respectively connected to the battery management system. The battery management system is connected to the on-board charger, the battery module and the heating module respectively; The slow charging and low temperature heating control system is configured to execute the steps of the slow charging and low temperature heating control method according to any one of claims 1 to 7.

[0014] In one possible implementation, the heating module is connected to the interior of the battery module via a resistance wire to achieve the heating function. This design allows heat to be transferred to the interior of the battery more directly and efficiently.

[0015] In a third aspect, a vehicle according to the present invention adopts the slow charging and low temperature heating control system according to the present invention.

[0016] The present invention has the following beneficial effects: 1. This invention only sets a low-temperature heating threshold, simplifying the control logic. Furthermore, when the power battery temperature falls below this threshold, the power battery does not need to immediately disconnect. Instead, the onboard charger first controls the high-voltage DC output current and transmits the relevant signal to the battery management system for comparative analysis before deciding whether to disconnect the switch. This improvement ensures that the onboard charger output current remains under control, effectively improving the stability and reliability of the slow-charging low-temperature heating function and enhancing the robustness of the system.

[0017] 2. This invention directly closes the switch when the power battery temperature exceeds the heating threshold, allowing the onboard charger to simultaneously heat and charge the power battery. This switching process not only simplifies and improves control, but also effectively shortens charging time and improves charging efficiency for users.

[0018] 3. During the heating process, the battery module charging current and the charger's maximum output current capability are crucial to the safe and stable operation of the system. This invention specifies that if the battery module charging current and the charger's maximum output current capability are not both less than or equal to the heating mode start current threshold, I2, this indicates an abnormality. At this point, the battery management system will promptly request to exit heating mode and report the fault for troubleshooting. This mechanism enables rapid response to abnormal conditions, preventing system damage or safety hazards caused by current anomalies, and further ensuring the safe and stable operation of the entire charging and heating system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the main flow chart of the slow charging and low temperature heating control method described in the embodiment of the present application; Figure 2 is a detailed flow chart of the slow charging and low temperature heating control method described in the embodiment of the present application; Figure 3 This is a principle block diagram of the slow charging and low temperature heating control system described in the embodiment of the present application; In the figure: 1. On-board charger, 2. Power battery, 21. Battery module, 22. Heating module, 3. Battery management system, 4. Switch. DETAILED DESCRIPTION

[0020] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will be able to understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for the purpose of illustrating the present invention and are not intended to limit the scope of protection of the present invention.

[0021] like Figure 1 As shown, in an embodiment of the present application, a slow charging and low temperature heating control method includes the following steps: When the vehicle is plugged in and enters the charging process, the battery management system 3 makes a judgment based on the battery module temperature and the low-temperature heating threshold.

[0022] If the battery module temperature is less than or equal to the low-temperature heating threshold, the battery management system 3 sends a heating mode request signal to the on-board charger 1 to request the on-board charger 1 to enter the low-temperature heating mode.

[0023] After receiving the heating mode request signal, onboard charger 1 switches to low-temperature heating mode. Onboard charger 1 controls the high-voltage DC output current to be less than or equal to I1, collects the high-voltage DC output current in real time, and sends it to battery management system 3. It also sends a signal to battery management system 3 indicating that the charger's maximum output current capability is less than or equal to I1. I1 is the minimum current output capability of the onboard charger at the current temperature. The minimum current output capability of the onboard charger varies at different temperatures, and the specific value is determined based on actual testing and calibration of product performance characteristics.

[0024] After receiving the high-voltage DC output current and the maximum output current capability of the charger, the battery management system 3 compares the battery module charging current and the maximum output current capability of the charger with the heating mode startup current threshold I2. Based on the comparison result, it determines whether to request to exit the heating mode. I2 is the heating mode startup current threshold, which is determined based on the actual vehicle system matching.

[0025] like Figure 2 As shown, in one possible embodiment, when both the charger's maximum output current capability and the battery module's charging current are less than or equal to I2, the battery management system 3 controls switch 4 (e.g., a high-voltage relay) to disconnect and sends a switch-off signal to the onboard charger 1. By precisely controlling the timing of switch 4's disconnection, preparations are made for the subsequent stable heating power adjustment phase, ensuring that the heating process starts within a safe current range.

[0026] like Figure 2 As shown, in one possible embodiment, when the onboard charger 1 receives a switch-off signal, it controls the high-voltage DC output current to be less than or equal to I3, collects the high-voltage DC output current in real time, and sends it to the battery management system 3. Simultaneously, it sends a signal indicating that the charger's maximum output current capability is less than or equal to I3 to the battery management system 3. The battery management system 3 calculates the heating power level based on the high-voltage DC output current and the charger's maximum output current capability, where I3 represents the current output capability of the onboard charger at the current temperature. This operation enables the onboard charger 1 to reasonably adjust the output current based on its own capabilities to adapt to heating requirements at different temperatures.

[0027] like Figure 2As shown, in one possible embodiment, after the battery management system 3 calculates the heating level based on the high-voltage DC output current and the maximum output current capability of the charger, it sends a heating level request signal to the heating module 22. The heating module 22 heats the battery module 21 in accordance with the heating level request signal. During the heating process, the battery module temperature is collected in real time and reported to the battery management system 3. By accurately calculating the heating level, heating energy can be rationally allocated based on actual conditions, avoiding energy waste or insufficient heating. Real-time collection and reporting of battery module temperature enables the battery management system 3 to promptly monitor the heating progress and battery status, providing a basis for subsequent adjustment of the control strategy based on temperature changes and ensuring that the heating process remains under control.

[0028] like Figure 2 As shown, in a possible embodiment, the battery management system 3 compares the received battery module temperature with the low-temperature heating threshold. When the battery module temperature is less than or equal to the low-temperature heating threshold, the current heating state is maintained; when the battery module temperature is greater than the low-temperature heating threshold, the battery management system 3 controls the switch 4 to close and sends a switch state closing signal to the on-board charger 1. After the on-board charger 1 receives the switch state closing signal, the on-board charger 1 controls the high-voltage DC output current to be less than or equal to I4 and collects the high-voltage DC output current in real time and sends it to the battery management system 3. At the same time, the signal indicating that the maximum output current capability of the charger is less than or equal to I4 is sent to the battery management system 3. The battery management system 3 calculates and dynamically allocates the charging power and heating power based on the high-voltage DC output current, the maximum output current capability of the charger and the battery module temperature to realize the function of charging and heating at the same time until the low-temperature heating mode is exited, where I4 is the maximum current output capability value of the on-board charger at the current temperature. When the battery module temperature is less than or equal to the low-temperature heating threshold, the heating state is maintained, ensuring continuous heating of the power battery 2 in low-temperature environments until it reaches the appropriate temperature. When the battery module temperature exceeds the low-temperature heating threshold, the control switch 4 closes and enters a simultaneous charging and heating mode, dynamically allocating charging and heating power based on various signals. This real-time temperature-adjusted control method effectively increases the battery temperature and promptly switches to a concurrent charging and heating mode when the temperature is appropriate, improving overall energy replenishment efficiency. Dynamic power allocation ensures stability and efficiency in the charging and heating processes.

[0029] In the embodiment of the present application, I4, I3, I2 and I1 satisfy the following relationship: I4>I3>I2>I1.

[0030] like Figure 2As shown, in one possible embodiment, after the vehicle is plugged in and enters the charging process, the battery module 21 in the power battery 2 reports the battery module temperature to the battery management system 3 in real time. If the battery module temperature is greater than the charging start temperature threshold, the charging mode is entered. If the battery module temperature is greater than the low-temperature heating threshold but less than or equal to the charging start temperature threshold, the charging and heating process is directly entered until the heating mode is finally exited. The low-temperature heating threshold is less than the charging start temperature threshold. This clarifies the operating mode of the system under different temperature conditions. If the battery module temperature is greater than the charging start temperature threshold after the vehicle is plugged in and enters the charging mode, unnecessary heating is avoided, saving time and energy. If the battery module temperature is greater than the low-temperature heating threshold but less than or equal to the charging start temperature threshold, the charging and heating process is directly entered. This simplifies the control process, enables the system to quickly respond to different temperature conditions, and selects the optimal operating mode based on actual conditions, thereby improving the system's adaptability and efficiency.

[0031] like Figure 2 As shown, in one possible embodiment, when the battery module charging current and the charger's maximum output current capability are not both less than or equal to I2, indicating an anomaly, the battery management system 3 requests exiting heating mode and reporting the fault for troubleshooting. This mechanism promptly detects current anomalies, preventing damage to batteries, charging equipment, and other components, thereby ensuring system safety and stability. By promptly exiting heating mode and providing a fault notification, users or maintenance personnel can quickly identify the problem and implement appropriate remedial measures, mitigating potential risks.

[0032] like Figure 3As shown, in an embodiment of the present application, a slow charging and low-temperature heating control system includes an on-board charger 1, a power battery 2 and a battery management system 3; the power battery 2 includes a battery module 21 and a heating module 22. The on-board charger 1 transmits the high-voltage DC output current and high-voltage DC output voltage to the battery module 21 and the heating module 22 in the power battery 2 through the DC bus to achieve charging and heating functions. At the same time, the on-board charger 1 is connected to the battery management system 3 through a signal harness, and signal transmission is achieved through the signal harness. The battery module 21 and the heating module 22 are connected to the high-voltage DC bus in a parallel structure inside the power battery 2, and the heating module 22 is connected to the inside of the battery module 21 through a resistance wire to achieve the heating function. A switch 4 is connected in series on the DC bus at the front end of the battery module 21. The switch 4 is used to cut off the input source of the high-voltage DC current and high-voltage DC voltage of the battery module 21. The battery module 21 and the heating module 22 are also connected to the battery management system 3 via signal harnesses, respectively, to report the battery module temperature and battery module charging current to the battery management system 3 in real time to control the switching between charging and heating modes. At the same time, the battery management system 3 sends a heating gear request signal to control the heating module 22 to heat the battery module 21. Ultimately, the battery module 21 in the power battery 2 is quickly heated, the charging speed is increased, and the charging time is shortened. The slow charging and low-temperature heating control system is configured to perform the steps of the slow charging and low-temperature heating control method in the embodiment of the present application.

[0033] like Figure 3 As shown, in one possible embodiment, the heating module 22 is connected to the interior of the battery module 21 via a resistance wire to achieve a heating function. This design of connecting to the interior of the battery module 21 via a resistance wire for heating enables heat to be transferred to the interior of the battery more directly and efficiently.

[0034] In an embodiment of the present application, a vehicle adopts a slow charging and low temperature heating control system as in the embodiment of the present application.

[0035] The vehicle may be, but is not limited to, a pure electric vehicle (Pure Electric Vehicle / Battery Electric Vehicle, PEV / BEV), a hybrid electric vehicle (Hybrid Electric Vehicle, HEV), a range extended electric vehicle (Range Extended Electric Vehicle, REEV), a plug-in hybrid electric vehicle (Plug-in Hybrid Electric Vehicle, PHEV), a new energy vehicle (New Energy Vehicle), etc.

[0036] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete the full classification or partial functions described above.

[0037] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A slow charging and low temperature heating control method, characterized in that: The following steps are involved: When the vehicle enters the charging process, the battery management system (3) makes a judgment based on the battery module temperature and the low-temperature heating threshold; If the battery module temperature is less than or equal to a low-temperature heating threshold, the battery management system (3) sends a heating mode request signal; After the on-board charger (1) receives the heating mode request signal, it controls the high-voltage DC output current to be less than or equal to I1 and collects the high-voltage DC output current in real time and sends it to the battery management system (3), and at the same time sends a signal indicating that the charger's maximum output current capability is less than or equal to I1 to the battery management system (3); After receiving the high-voltage direct current output current and the maximum output current capability of the charger, the battery management system (3) compares the battery module charging current, the maximum output current capability of the charger and the heating mode start current threshold I2, and decides whether to request to exit the heating mode based on the comparison result; Among them, I2>I1, I1 is the minimum current output capacity value of the on-board charger at the current temperature, and I2 is the starting current threshold of the heating mode.

2. The slow charging and low temperature heating control method according to claim 1, characterized in that: When the maximum output current capability of the charger and the battery module charging current are both less than or equal to I2, the battery management system (3) controls the switch (4) to disconnect and sends a switch state disconnection signal to the on-board charger (1).

3. The slow charging and low temperature heating control method according to claim 2, characterized in that: After receiving the switch state disconnection signal, the on-board charger (1) controls the high-voltage direct current output current to be less than or equal to I3 and collects the high-voltage direct current output current in real time and sends it to the battery management system (3). At the same time, a signal indicating that the charger's maximum output current capacity is less than or equal to I3 is sent to the battery management system (3) for heating power gear calculation, wherein I3>I2, and I3 is the current output capacity value of the on-board charger at the current temperature.

4. The slow charging and low temperature heating control method according to claim 3, characterized in that: The battery management system (3) calculates the heating gear based on the high-voltage direct current output current and the maximum output current capacity of the charger, and then controls the heating module (22) to heat the battery module (21). During the heating process, the battery module temperature is collected in real time and reported to the battery management system (3).

5. The slow charging and low temperature heating control method according to claim 4, characterized in that: The battery management system (3) compares the received battery module temperature with a low-temperature heating threshold. When the battery module temperature is less than or equal to the low-temperature heating threshold, the current heating state is maintained; when the battery module temperature is greater than the low-temperature heating threshold, the battery management system (3) controls the switch (4) to close and sends a switch state closing signal to the on-board charger (1), and the on-board charger (1) controls the high-voltage DC output current to be less than or equal to I4 and collects the high-voltage DC output current in real time and sends it to the battery management system (3), and at the same time sends a signal indicating that the maximum output current capacity of the charger is less than or equal to I4 to the battery management system (3). The battery management system (3) calculates and dynamically allocates the charging power and the heating power based on the high-voltage DC output current, the maximum output current capacity of the charger and the battery module temperature, realizing the function of charging and heating at the same time until the low-temperature heating mode is exited, wherein I4>I3, I4 is the maximum current output capacity value of the on-board charger at the current temperature.

6. The slow charging and low temperature heating control method according to claim 1, characterized in that: If the battery module temperature is greater than the charging start temperature threshold after the charging gun is plugged in, the charging mode is entered; if the battery module temperature is greater than the low-temperature heating threshold but less than or equal to the charging start temperature threshold, the charging and heating process is directly entered until the heating mode is finally exited, wherein the low-temperature heating threshold is less than the charging start temperature threshold.

7. The slow charging and low temperature heating control method according to claim 1, characterized in that: When the battery module charging current and the charger maximum output current capability are not both less than or equal to I2, it indicates that an abnormality exists, and the battery management system (3) requests to exit the heating mode and reports the fault prompt for troubleshooting.

8. A slow charging and low temperature heating control system, comprising an on-board charger (1), a power battery (2) and a battery management system (3), characterized in that: The power battery (2) comprises a battery module (21) and a heating module (22), wherein the heating module (22) is used to heat the battery module (21); The on-board charger (1) is connected to the battery module (21) and the heating module (22) respectively, and a switch (4) is connected between the on-board charger (1) and the battery module (21); The battery module (21) and the heating module (22) are respectively connected to the battery management system (3). The battery management system (3) is connected to the on-board charger (1), the battery module (21) and the heating module (22) respectively; The slow charging and low temperature heating control system is configured to execute the steps of the slow charging and low temperature heating control method according to any one of claims 1 to 7.

9. The slow charging and low temperature heating control system according to claim 8, characterized in that: The heating module (22) is connected to the interior of the battery module (21) via a resistance wire to achieve a heating function.

10. A vehicle, characterized in that: The slow charging and low temperature heating control system as claimed in claim 8 or 9 is adopted.

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