Charging control method and system of power battery and vehicle

Abstract

The invention relates to the technical field of battery charging, in particular to a charging control method and system of a power battery and a vehicle. The remaining charging time and the remaining available maximum charging time are determined, the remaining charging time is the time required by the power battery to be fully charged from the current electric quantity, and the remaining available maximum charging time is equal to the result of subtracting the current time from the reserved vehicle using time; when it is judged that the remaining available maximum charging time is larger than the remaining charging time, the charging current is dynamically adjusted based on the BMS request charging current, the remaining charging time and the remaining available maximum charging time, and the charging current is smaller than the BMS request charging current; and performing charging control based on the charging current. According to the method, the remaining available maximum charging time can be intelligently calculated for the reserved vehicle use, and when the remaining available maximum charging time is longer than the remaining charging time, a mild charging mode is adopted to prolong the service life of the power battery.

Description

Technical Field

[0001] The present invention relates to the technical field of power battery charging, and in particular to a power battery charging control method, system and vehicle. Background Art

[0002] With the continuous advancement and popularization of electric vehicle technology, users' requirements for electric vehicle experience and battery management efficiency are increasing. Current control during electric vehicle charging is one of the key factors affecting the life and charging efficiency of power batteries. Traditional charging methods often use a fixed charging current, which lacks flexible response to users' actual car needs. In some special scenarios, in order to shorten the charging time and meet users' demand for high charging efficiency, the fixed current may be set relatively large. However, although this approach can charge more power to the power battery in a short period of time, in the long run, excessive current may damage the power battery, accelerate the aging process of the power battery, and thus shorten the service life of the power battery.

[0003] In recent years, although some intelligent charging systems have appeared on the market that can automatically adjust the charging current according to the status of the power battery (such as battery temperature, power level, etc.), most of these systems are only based on the immediate status of the power battery itself for regulation and control, and fail to fully consider the user's actual vehicle usage plans and needs.

[0004] Therefore, it is necessary to develop a new power battery charging control method, system and vehicle. Summary of the invention

[0005] The object of the present invention is to provide a charging control method, system and vehicle for a power battery, which can adjust the charging current according to the user's actual vehicle use plan and needs to extend the service life of the power battery.

[0006] In a first aspect, a method for controlling charging of a power battery according to the present invention comprises the following steps: Get the reserved car time; Determine the remaining charging time and the remaining maximum available charging time, wherein the remaining charging time is the time required for the power battery to be fully charged from the current power level, and the remaining maximum available charging time is equal to the reserved vehicle time minus the current time; When it is determined that the remaining available maximum charging time is greater than the remaining charging time, dynamically adjusting the charging current based on the BMS requested charging current, the remaining charging time, and the remaining available maximum charging time, the charging current being less than the BMS requested charging current; Charging control is performed based on the charging current.

[0007] Optionally, the charging current is determined as follows: Charging current = BMS requested charging current * (remaining charging time ÷ remaining available maximum charging time). By dynamically adjusting the charging current to match the remaining charging time and the remaining available maximum charging time, a more gentle charging method can be achieved without affecting the user's use of the vehicle, thereby extending the service life of the power battery.

[0008] Optionally, the vehicle has a charging and heating mode, and the conditions for the vehicle to enter the charging and heating mode are: When there is no heating circuit fault and no fault prohibiting heating, when it is determined that the minimum value of the battery cell temperature is greater than or equal to the charging lower limit temperature and less than the heating start temperature + CAL1, and the charging capacity of the external charging equipment is greater than the sum of the allowable charging capacity of the power battery and the threshold of heating while charging, the vehicle enters the heating while charging mode; Among them, CAL1 is the first preset value; the threshold for heating while charging is determined according to the current battery system voltage and PTC internal resistance. The threshold for heating while charging is set to a dynamically adjusted value to ensure that the battery system can still accurately control the balance between heating and charging in an extremely low temperature environment. This design effectively avoids frequent fluctuations in the temperature of the power battery, which not only ensures the smooth progress of the charging process, but also prevents charging interruptions or overheating problems that may be caused by unstable temperature, and effectively maintains the health of the power battery. In addition, this strategy also simplifies the calibration test process, improves development efficiency, and reduces overall costs.

[0009] Optionally, the method for determining the threshold of heating while charging is: The threshold for heating while charging = current battery system voltage ÷ PTC internal resistance. The present invention dynamically adjusts the threshold for heating while charging based on the real-time battery system voltage and PTC internal resistance, thus realizing intelligent management of the PTC heating element. This design can not only maximize the heating efficiency of the PTC and accelerate the charging process, but also avoid the problem of limited charging efficiency due to excessive current, ensuring that the power battery can be charged in the most optimized state, thereby improving the overall charging rate and efficiency.

[0010] Optionally, the vehicle also has a charging and non-heating mode. When the vehicle is in the charging and heating mode or in the initial state, the charging and non-heating mode is entered when any of the following conditions is met; Condition 1: The minimum value of the battery cell temperature is greater than or equal to the heating start temperature + CAL1; the heating start temperature is higher than the charging lower limit temperature.

[0011] Condition 2: The maximum value of the battery cell temperature is greater than or equal to the cooling start temperature.

[0012] Condition 3: The charging capacity of the power battery is greater than the charging capacity of the external charging equipment.

[0013] The initial state is the first state after the external charging device is connected and the charging initialization process is completed. Under certain conditions, the vehicle can intelligently switch from charging and heating mode to charging without heating mode. This helps to avoid unnecessary heating operations when the battery temperature is already high enough or the charging capacity of the external charging device is insufficient. This strategy helps to protect the health of the power battery and improve charging efficiency and safety. At the same time, the strategy also takes into account the initial state of the vehicle to ensure that the vehicle can correctly enter the corresponding charging mode after connecting to the external charging device and completing the initialization process.

[0014] Optionally, the vehicle also has a no-charging and no-heating mode, and the conditions for the vehicle to enter the no-charging and no-heating mode are: The minimum temperature of the battery cell is lower than the lower limit temperature of charging and a preset fault occurs; The preset fault includes at least one of a heating circuit fault and a heating prohibition fault. This is a safety protection measure to prevent the power battery from being charged or heated under adverse conditions, thereby avoiding potential power battery damage or safety accidents. By entering the no-charging and no-heating mode in a timely manner, the vehicle can ensure that it remains in a safe state in the event of a fault, waiting for further maintenance or inspection.

[0015] Optionally, the vehicle also has a non-charging and heating mode, and the conditions for entering the non-charging and heating mode from the non-charging and non-heating mode or the initial state are: When there is no heating circuit fault and no fault prohibiting heating, the minimum value of the battery cell temperature is less than the lower limit temperature for charging. The vehicle is equipped with a non-charging and heating mode. After eliminating the heating circuit fault and the conditions prohibiting heating, it is enabled when the battery cell temperature is lower than the lower limit temperature for charging. The power battery can only be charged after it is heated to the appropriate temperature range. This mechanism ensures that the power battery is charged under the optimal temperature conditions, prolongs the life of the power battery, and improves charging efficiency and safety.

[0016] Optionally, the condition for the vehicle to enter the charging and non-heating mode from the non-charging and heating mode is: When there is no heating circuit fault and no fault prohibiting heating occurs, when the minimum value of the battery cell temperature is greater than or equal to the lower limit temperature of charging + CAL2, and the charging capacity of the external device is ≤ the allowable charging capacity of the power battery; Or Tmax ≥ cooling start temperature; Among them, CAL2 is the second preset value. This design ensures that when the battery temperature reaches the range suitable for charging (i.e. greater than or equal to the lower limit temperature of charging + CAL2), and the charging capacity of the external charging equipment does not exceed the maximum charging capacity allowed by the power battery, the vehicle can safely and effectively switch from heating mode to charging mode. In addition, when the battery temperature reaches or exceeds the cooling start temperature, the vehicle is also allowed to enter the charging without heating mode to prevent the power battery from overheating. This intelligent switching mechanism helps to protect the health of the power battery and improve charging efficiency and safety.

[0017] In a second aspect, a power battery charging control system according to the present invention comprises: A memory for storing a computer readable program; A controller is used to call the computer-readable program to execute the steps of the power battery charging control method as described in the present invention.

[0018] In a third aspect, a vehicle according to the present invention stores a computer-readable program therein, and when the computer-readable program is called, the steps of the power battery charging control method according to the present invention can be executed.

[0019] Beneficial effects of the present invention: (1) For the scenario where users make car reservations, the present invention calculates the difference between the reservation time and the current time to obtain the maximum remaining available charging period. When this period is sufficient to cover the charging time required for the power battery, the system will automatically adjust to a more gentle charging mode. This strategy effectively reduces the heat generated by the power battery during charging, reduces the damage to the power battery caused by thermal stress, and slows down the chemical aging process of the power battery, significantly extending the cycle life of the power battery.

[0020] (2) The present invention innovatively sets the threshold for heating while charging as a dynamic adjustment value, ensuring that the system can still accurately control the balance between heating and charging in an extremely low temperature environment. This design effectively avoids frequent fluctuations in battery temperature, not only ensuring the smooth progress of the charging process, but also preventing charging interruptions or overheating problems that may be caused by unstable temperature, effectively maintaining the health of the power battery. In addition, this strategy also simplifies the calibration test process, improves development efficiency, and reduces overall costs.

[0021] (3) The present invention dynamically adjusts the threshold of heating while charging based on the real-time system voltage and PCT internal resistance, thus realizing intelligent management of the PTC heating element. The present invention can maximize the heating efficiency of the PTC and accelerate the charging process, while avoiding the problem of limited charging efficiency due to excessive current, ensuring that the power battery can be charged in the most optimized state, thereby improving the overall charging rate and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of a charging control method for a power battery described in an embodiment of the present application; Figure 2 Schematic diagram of switching between modes in the embodiment of the present application; Figure 3 This is a principle block diagram of a charging control system for a power battery described in an embodiment of the present application; In the figure: 1- memory, 2- controller. DETAILED DESCRIPTION

[0023] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can 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 illustrating the present invention, not for limiting the scope of protection of the present invention.

[0024] like Figure 1 As shown, in an embodiment of the present application, a charging control method for a power battery includes the following steps: Get the scheduled car time.

[0025] Determine the remaining charging time and the remaining maximum available charging time, where the remaining charging time is the time required to charge the power battery from the current power to full charge, and the remaining maximum available charging time is equal to the reserved vehicle time minus the current time.

[0026] When it is determined that the remaining available maximum charging time is greater than the remaining charging time, the charging current is dynamically adjusted based on the BMS requested charging current, the remaining charging time and the remaining available maximum charging time, and the charging current is less than the BMS requested charging current.

[0027] Charging control is performed based on the charging current.

[0028] When the user has a car use plan, the reserved car use time is obtained, and the remaining available maximum charging time is calculated based on the reserved car use time and the current time. When the remaining available maximum charging time is greater than the remaining charging time, the battery system uses a more gentle charging current for charging. A gentle charging current can reduce the heat generated by the power battery during the charging process, thereby reducing the thermal stress of the power battery and reducing power battery damage caused by high temperature. In addition, a gentle charging method can also help slow down the chemical aging of the power battery and extend the cycle life of the power battery.

[0029] If the user has no plan to use the car, charging will be carried out according to the existing charging method.

[0030] In a possible embodiment, when a user has a plan to use the vehicle, the user sets the reservation time through a mobile phone APP, and the vehicle then obtains the reservation time from the mobile phone APP through the network.

[0031] In a possible embodiment, the charging current is determined as follows: Charging current = BMS requested charging current * (remaining charging time ÷ remaining available maximum charging time). This method dynamically adjusts the charging current to match the remaining charging time and the remaining available maximum charging time. This helps to achieve a gentler charging method without affecting the user's use of the vehicle, thereby extending the service life of the power battery.

[0032] In addition, low temperature is also a key factor affecting the life and performance of power batteries. Taking lithium batteries as an example, low temperature will greatly weaken the performance of lithium batteries and prolong the charging time, which not only reduces the user experience, but also restricts the popularity of electric vehicles. In addition, the health of lithium batteries that are in a low temperature state for a long time will also be significantly affected. Therefore, keeping the power battery at the optimal operating temperature has become a problem that must be solved in the industry. At present, the basic strategy adopted by many electric vehicles is to heat the power battery at low temperatures and then charge it with AC, or use a simple threshold to determine the timing of entering the charging and heating mode. However, the simple design may fail at extremely low temperatures, causing the power battery temperature to fluctuate repeatedly, and charging to be suspended or continuously heated. This will affect the health of the power battery and give users a very bad charging experience.

[0033] In order to avoid the adverse effects of low temperature on power batteries, such as Figure 2 As shown, the vehicle is configured with the following multiple modes: Mode 1: No charging and no heating mode.

[0034] Mode 2: No charging and heating mode.

[0035] Mode 3: Charging and heating mode.

[0036] Mode 4: Charging without heating.

[0037] In a possible embodiment, the vehicle enters the charging and heating mode (i.e., mode 3) from the initial state or the non-charging and heating mode (i.e., mode 2) under the condition (i.e. Figure 2 Condition 5) in is: When there is no heating circuit fault and no fault prohibiting heating, when it is determined that the minimum value of the battery cell temperature is greater than or equal to the lower limit charging temperature and less than the heating start temperature + CAL1, and the charging capacity of the external charging equipment is greater than the sum of the allowable charging capacity of the power battery and the threshold of heating while charging, the vehicle enters the charging and heating mode. Among them, CAL1 is the first preset value; the threshold of heating while charging is determined according to the current battery system voltage and PTC internal resistance. Since the threshold of heating while charging is a dynamic value, the adaptability of the system is significantly improved. By real-time monitoring of the current battery system voltage and PTC internal resistance, the system can intelligently adjust the threshold of heating while charging, thereby maximizing the heating capacity of PTC (positive temperature coefficient thermistor).

[0038] In a possible embodiment, the condition for the vehicle to switch from the charging and non-heating mode (i.e., mode 4) to the charging and heating mode (i.e., mode 3) is: When there is no heating circuit fault and no fault prohibiting heating occurs, the minimum temperature of the battery cell drops to a level greater than or equal to the lower charging limit temperature and less than the heating start-up temperature + CAL1, and the charging capacity of the external charging device is greater than the sum of the battery's allowable charging capacity and the threshold for heating while charging.

[0039] In a possible embodiment, a method for determining a threshold value of heating while charging is as follows: Heating threshold while charging = current battery system voltage ÷ PTC internal resistance.

[0040] This method can accurately control the threshold of heating while charging even under extremely low temperature conditions by designing the threshold of heating while charging as a dynamic value, thereby avoiding repeated fluctuations in battery temperature. This precise control not only ensures the smooth progress of the charging process, but also effectively prevents the phenomenon of charging suspension or continuous heating caused by temperature fluctuations, thereby protecting the health of the power battery. In addition, it also reduces the task items of calibration testing. In the past, engineers needed to perform a large number of calibration tests to ensure the stability of the system under various conditions. Now, because the system can dynamically adjust the threshold of heating while charging and keep the temperature of the power battery stable, the number and complexity of these tests have been significantly reduced, thereby improving development efficiency and reducing costs. In addition, by dynamically adjusting the threshold of heating while charging in the entry condition of the heating while charging mode based on the real-time current battery system voltage, the PTC can be used to heat the power battery to the maximum extent and improve the charging rate, and excessive current can be prevented from flowing into the PTC, resulting in the failure to charge according to the maximum capacity of the power battery, thereby affecting the charging rate.

[0041] like Figure 2As shown, in a possible embodiment, when the vehicle is in the charging and heating mode (i.e., mode 3) or the initial state, when any of the following conditions (i.e. Figure 2 When condition 6) in the above is met, the charging mode without heating (i.e. mode 4) is entered; Condition a: The minimum value of the battery cell temperature is greater than or equal to the heating start temperature + CAL1.

[0042] Condition b: The maximum value of the battery cell temperature is greater than or equal to the cooling start temperature.

[0043] Condition c: The allowable charging capacity of the power battery is greater than the charging capacity of the external charging equipment.

[0044] The initial state is the first state after the external charging device is connected and the charging initialization process is completed (i.e. Figure 2 Condition 1 in ). Under certain conditions, the vehicle can intelligently switch from charging and heating mode to charging without heating mode. This helps avoid unnecessary heating when the battery temperature is already high enough or the external charging device has insufficient charging capacity. This strategy helps protect the health of the power battery and improve charging efficiency and safety. At the same time, the strategy also takes into account the initial state of the vehicle, ensuring that the vehicle can correctly enter the corresponding charging mode after connecting to the external charging device and completing the initialization process.

[0045] like Figure 2 As shown, in a possible embodiment, the vehicle enters the non-charging and heating mode (i.e., mode 2) from the initial state and the non-charging and non-heating mode (i.e., mode 1) under the condition (i.e., Figure 2 Condition 3) in is: When there is no heating circuit fault and no fault prohibiting heating occurs, the minimum value of the battery cell temperature is less than the lower limit temperature of charging.

[0046] like Figure 2 As shown, in a possible embodiment, the condition for the vehicle to enter the non-charging and heating mode (i.e., mode 2) from the charging and heating mode (i.e., mode 3) is: When there is no heating circuit fault and no fault that prohibits heating, the minimum value of the battery cell temperature drops to less than the charging lower limit temperature.

[0047] like Figure 2 As shown, in a possible embodiment, the vehicle switches from the non-charging and heating mode (i.e., mode 2) to the charging and non-heating mode (i.e., mode 4) under the following conditions (i.e., Figure 2 Condition 4) in is: When there is no heating circuit fault and no fault prohibiting heating, when the minimum value of the battery cell temperature is greater than or equal to the lower limit charging temperature + CAL2, and the charging capacity of the external device ≤ the allowable charging capacity of the power battery; or Tmax ≥ the cooling start temperature; wherein CAL2 is the second preset value. This method ensures that when the battery temperature reaches a suitable charging range (i.e., greater than or equal to the lower limit charging temperature + CAL2), and the charging capacity of the external charging device does not exceed the maximum charging capacity allowed by the power battery, the vehicle can safely and effectively switch from heating mode to charging mode. In addition, when the power battery temperature reaches or exceeds the cooling start temperature, the vehicle is also allowed to enter the charging and non-heating mode to prevent the power battery from overheating. This intelligent switching mechanism helps to protect the health of the power battery and improve charging efficiency and safety.

[0048] In the embodiment of the present application, CAL1 and CAL2 are both calibrated values.

[0049] like Figure 2 As shown, in a possible embodiment, the vehicle enters the condition of no charging and no heating mode (ie, mode 1) (ie Figure 2 Condition 1) in is: The minimum temperature of the battery cell is less than the lower limit temperature for charging and a preset fault occurs; the preset fault includes at least one of a heating circuit fault and a heating prohibition fault. When the power battery temperature is too low (less than the lower limit temperature for charging) and a preset fault occurs (such as a heating circuit fault or a heating prohibition fault), the vehicle will automatically enter the no-charging and no-heating mode. This is a safety protection measure designed to prevent the power battery from being charged or heated under adverse conditions, thereby avoiding potential power battery damage or safety accidents. By entering the no-charging and no-heating mode in a timely manner, the vehicle can ensure that it remains in a safe state in the event of a fault, awaiting further repairs or inspections.

[0050] like Figure 3 As shown, in an embodiment of the present application, a charging control system for a power battery includes a memory 1 and a controller 2. The memory 1 stores a computer-readable program. When the computer-readable program is called by the controller 2, it can execute the steps of the power battery charging control method described in the embodiment of the present application.

[0051] In an embodiment of the present application, a vehicle adopts the charging control system of the power battery described in the embodiment of the present application.

[0052] The above-mentioned embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A charging control method for a power battery, characterized in that: The following steps are involved: Get the reserved car time; Determine the remaining charging time and the remaining maximum available charging time, wherein the remaining charging time is the time required for the power battery to be fully charged from the current power level, and the remaining maximum available charging time is equal to the reserved vehicle time minus the current time; When it is determined that the remaining available maximum charging time is greater than the remaining charging time, dynamically adjusting the charging current based on the BMS requested charging current, the remaining charging time, and the remaining available maximum charging time, the charging current being less than the BMS requested charging current; Charging control is performed based on the charging current.

2. The power battery charging control method according to claim 1, characterized in that: The method for determining the charging current is as follows: Charging current = BMS requested charging current * (remaining charging time ÷ remaining available maximum charging time).

3. The power battery charging control method according to claim 1, characterized in that: The vehicle has a charging and heating mode. The conditions for the vehicle to enter the charging and heating mode are: When there is no heating circuit fault and no fault prohibiting heating, when it is determined that the minimum value of the battery cell temperature is greater than or equal to the charging lower limit temperature and less than the heating start temperature + CAL1, and the charging capacity of the external charging equipment is greater than the sum of the allowable charging capacity of the power battery and the threshold of heating while charging, the vehicle enters the heating while charging mode; Among them, CAL1 is a first preset value; the heating-while-charging threshold is determined according to the current battery system voltage and PTC internal resistance.

4. The power battery charging control method according to claim 3, characterized in that: The method for determining the heating-while-charging threshold is as follows: Heating threshold while charging = current battery system voltage ÷ PTC internal resistance.

5. The power battery charging control method according to claim 3, characterized in that: The vehicle also has a charging and non-heating mode. When the vehicle is in the charging and heating mode or the initial state, it enters the charging and non-heating mode when any of the following conditions are met; Condition 1: The minimum value of the battery cell temperature is greater than or equal to the heating start temperature + CAL1; Condition 2: The maximum value of the battery cell temperature is greater than or equal to the cooling start temperature; Condition 3: The charging capacity of the power battery is greater than the charging capacity of the external charging equipment; The initial state is the first state after the external charging device is connected and the charging initialization process is completed.

6. The power battery charging control method according to claim 5, characterized in that: The vehicle also has a no-charging and no-heating mode. The conditions for entering the no-charging and no-heating mode are: The minimum temperature of the battery cell is lower than the lower limit temperature of charging and a preset fault occurs; The preset fault includes at least one of a heating circuit fault and a heating prohibition fault.

7. The power battery charging control method according to claim 6, characterized in that: The vehicle also has a non-charging and heating mode. The conditions for entering the non-charging and heating mode from the non-charging and non-heating mode or the initial state are: When there is no heating circuit fault and no fault prohibiting heating occurs, the minimum value of the battery cell temperature is less than the lower limit temperature of charging.

8. The power battery charging control method according to claim 7, characterized in that: The conditions for the vehicle to enter the charging and non-heating mode from the non-charging and heating mode are: When the minimum value of the battery cell temperature is greater than or equal to the lower limit temperature of charging + CAL2, and the charging capacity of the external device is less than or equal to the allowable charging capacity of the power battery; Or Tmax ≥ cooling start temperature; Among them, CAL2 is the second preset value.

9. A power battery charging control system, characterized in that: include: A memory (1) for storing a computer-readable program; A controller (2) is used to call the computer-readable program to execute the steps of the power battery charging control method according to any one of claims 1 to 8.

10. A vehicle, characterized in that: A charging control system for a power battery as claimed in claim 9 is adopted.

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