Charging control method and system of power battery and vehicle

Abstract

The application relates to the technical field of battery charging, in particular to a charging control method and system of a power battery and a vehicle, which comprises the following steps: acquiring a reservation vehicle time; determining a residual charging time and a residual available maximum charging time, wherein the residual charging time is the time required for charging the power battery from the current power to full power, and the residual available maximum charging time is equal to the reservation vehicle time minus the current time; when it is judged that the residual available maximum charging time is greater than the residual charging time, dynamically adjusting a charging current based on a BMS requested charging current, the residual charging time and the residual available maximum charging time, and the charging current is less than the BMS requested charging current; and performing charging control based on the charging current. The application can intelligently calculate the residual available maximum charging time for the reservation vehicle, and when the residual available maximum charging time is greater than the residual charging time, a moderate charging mode is adopted to prolong the service life of the power battery.

Description

Technical Field

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

[0002] With the continuous advancement and popularization of electric vehicle technology, users are increasingly demanding higher standards for the user experience and battery management efficiency. Current control during electric vehicle charging is a key factor affecting battery life and charging efficiency. Traditional charging methods often employ a fixed charging current, which lacks flexibility to meet actual user needs. In certain scenarios, to shorten charging time and meet high charging efficiency requirements, the fixed current may be set relatively high. However, while this approach can charge the battery more power in a short time, excessive current can damage the battery in the long run, accelerating its aging process and shortening its lifespan.

[0003] In recent years, although some intelligent charging systems have emerged on the market that can automatically adjust the charging current based on the state of the power battery (such as battery temperature and charge), most of these systems only adjust based on the real-time state of the power battery itself and fail to fully consider the user's actual vehicle use plan and needs.

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

[0005] The purpose of this 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, so as to extend the service life of the power battery.

[0006] In a first aspect, the present invention provides a charging control method for a power battery, comprising the following steps:

[0007] Get your reserved car time;

[0008] 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 charge from its current charge level to full charge, and the remaining maximum available charging time is equal to the scheduled vehicle usage time minus the current time;

[0009] 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, wherein the charging current is less than the BMS requested charging current.

[0010] Charging control is performed based on the charging current.

[0011] Optionally, the charging current is determined as follows:

[0012] Charging current = BMS requested charging current * (remaining charging time ÷ remaining maximum available charging time). By dynamically adjusting the charging current to match the remaining charging time and remaining maximum available charging time, a gentler charging method is achieved without affecting user vehicle operation, thereby extending the lifespan of the power battery.

[0013] Optionally, the vehicle has a charging and heating mode. The conditions for the vehicle to enter the charging and heating mode are as follows:

[0014] When there is no heating circuit fault and no heating prohibition fault occurs, when it is determined that the minimum temperature of the battery cell is greater than or equal to the lower charging 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 charging and heating threshold, the vehicle enters the charging and heating mode.

[0015] CAL1 is the first preset value; the simultaneous charging and heating threshold is determined based on the current battery system voltage and PTC internal resistance. Setting the simultaneous charging and heating threshold as a dynamically adjustable value ensures that the battery system can accurately control the balance between heating and charging even in extremely low-temperature environments. This design effectively avoids frequent fluctuations in the power battery temperature, ensuring not only a smooth charging process but also preventing charging interruptions or overheating problems that may occur due to temperature instability, thus effectively maintaining the health of the power battery. In addition, this strategy simplifies the calibration and testing process, improves development efficiency, and reduces overall costs.

[0016] Optionally, the method for determining the simultaneous charging and heating threshold is as follows:

[0017] The simultaneous charging and heating threshold is calculated as: Current battery system voltage ÷ PTC internal resistance. This invention dynamically adjusts the simultaneous charging and heating threshold based on real-time battery system voltage and PTC internal resistance, achieving intelligent management of the PTC heating element. This design maximizes the utilization of the PTC's heating efficiency, accelerating the charging process, while avoiding the problem of limited charging efficiency due to excessive current. This ensures the power battery can be charged in an optimized state, thereby improving the overall charging rate and efficiency.

[0018] Optionally, the vehicle also has a charging and not heating mode. When the vehicle is in the charging and heating mode or in the initial state, it enters the charging and not heating mode when any of the following conditions are met.

[0019] Condition 1: The minimum temperature of a single battery cell is greater than or equal to the heating start temperature + CAL1; the heating start temperature is higher than the lower charging limit temperature.

[0020] Condition 2: The maximum temperature of a single battery cell is greater than or equal to the cooling start temperature.

[0021] Condition 3: The charging capacity of the power battery is greater than the charging capacity of the external charging equipment.

[0022] The initial state refers to the first state after connecting to an external charging device and completing the charging initialization process. Under certain conditions, the vehicle can intelligently switch from a charging-while-heating mode to a charging-without-heating mode. This helps avoid unnecessary heating operations when the battery temperature is already high enough or the external charging device's charging capacity is insufficient. This strategy helps protect the health of the power battery and improves charging efficiency and safety. Simultaneously, this strategy also considers the vehicle's initial state, ensuring that the vehicle correctly enters the appropriate charging mode after connecting to the external charging device and completing the initialization process.

[0023] Optionally, the vehicle also has a non-charging and non-heating mode. The conditions for the vehicle to enter the non-charging and non-heating mode are as follows:

[0024] The minimum temperature of a single battery cell is lower than the lower limit of charging temperature and a preset fault occurs;

[0025] The preset faults include at least one of a heating circuit fault and a heating prohibition fault. This is a safety protection measure designed to prevent charging or heating of the power battery under adverse conditions, thereby avoiding potential power battery damage or safety accidents. By promptly entering a non-charging and non-heating mode, the vehicle can ensure a safe state in the event of a fault, awaiting further repair or inspection.

[0026] Optionally, 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 heating mode or the initial state are as follows:

[0027] When there is no heating circuit fault and no heating-prohibition fault occurs, the minimum temperature of the battery cells is lower than the lower charging limit temperature. The vehicle adds a non-charging, heating-only mode, which is activated after ruling out heating circuit faults and heating-prohibition conditions, when the battery cell temperature is below the lower charging limit temperature. This mode heats the battery to a suitable temperature range before charging can begin. This mechanism ensures the battery is charged under optimal temperature conditions, extending battery life and improving charging efficiency and safety.

[0028] Optionally, the conditions for the vehicle to switch from non-charging and heating mode to charging and non-heating mode are as follows:

[0029] When there is no heating circuit fault and no fault prohibiting heating, the minimum temperature of the battery cell is greater than or equal to the lower charging limit temperature + CAL2, and the charging capacity of the external device is less than or equal to the allowable charging capacity of the power battery.

[0030] Or Tmax ≥ cooling start temperature;

[0031] CAL2 is the second preset value. This design ensures that when the battery temperature reaches a suitable charging range (i.e., greater than or equal to the lower charging limit temperature + CAL2), and the charging capacity of the external charging equipment does not exceed the maximum allowable charging capacity of the power battery, the vehicle can safely and effectively switch from heating mode to charging mode. Furthermore, when the battery temperature reaches or exceeds the cooling activation temperature, the vehicle is also allowed to enter a charging without heating mode to prevent the power battery from overheating. This intelligent switching mechanism helps protect the health of the power battery and improves charging efficiency and safety.

[0032] Secondly, the charging control system for a power battery according to the present invention includes:

[0033] Memory, used to store computer-readable programs;

[0034] A controller is used to invoke the computer-readable program to perform the steps of the charging control method for a power battery as described in this invention.

[0035] Thirdly, the present invention provides a vehicle that stores a computer-readable program, which, when invoked, can execute the steps of the charging control method for a power battery as described in the present invention.

[0036] The beneficial effects of this invention are:

[0037] (1) For user-booked vehicle scenarios, this invention calculates the difference between the booked time and the current time to determine the maximum remaining available charging period. When this period is sufficient to cover the charging time required by the power battery, the system automatically adjusts to a gentler charging mode. This strategy effectively reduces the heat generated by the power battery during charging, alleviates the damage to the power battery caused by thermal stress, slows down the chemical aging process of the power battery, and significantly extends the cycle life of the power battery.

[0038] (2) This invention innovatively sets the threshold for simultaneous charging and heating as a dynamically adjustable value, ensuring that the system can still accurately control the balance between heating and charging even in extremely low-temperature environments. This design effectively avoids frequent fluctuations in battery temperature, ensuring not only a smooth charging process but also preventing charging interruptions or overheating problems that may be caused by unstable temperatures, thus effectively maintaining the health of the power battery. In addition, this strategy simplifies the calibration and testing process, improves development efficiency, and reduces overall costs.

[0039] (3) The present invention dynamically adjusts the charging and heating threshold based on the real-time system voltage and PCT internal resistance, thereby realizing intelligent management of the PTC heating element. The present invention can maximize the use of PTC heating efficiency and accelerate the charging process, while avoiding the problem of limited charging efficiency caused by excessive current, ensuring that the power battery can be charged in the optimal state, thereby improving the overall charging rate and efficiency. Attached Figure Description

[0040] Figure 1 This is a flowchart of the charging control method for the power battery described in the embodiments of this application;

[0041] Figure 2 This is a schematic diagram illustrating the switching of various modes in the embodiments of this application;

[0042] Figure 3 This is a schematic block diagram of the charging control system of the power battery described in the embodiments of this application;

[0043] In the diagram: 1-Memory, 2-Controller. Detailed Implementation

[0044] The embodiments of the present invention will be described below 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 content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed 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 and not for limiting the scope of protection of the present invention.

[0045] like Figure 1 As shown in the embodiments of this application, a charging control method for a power battery includes the following steps:

[0046] Get your reserved car time.

[0047] Determine the remaining charging time and the remaining maximum available charging time. The remaining charging time is the time required for the power battery to charge from its current charge level to full capacity. The remaining maximum available charging time is equal to the scheduled vehicle usage time minus the current time.

[0048] 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, so that the charging current is less than the BMS requested charging current.

[0049] Charging control is based on the charging current.

[0050] When a user has a vehicle booking plan, the system obtains the scheduled usage time and calculates the remaining maximum available charging time based on the scheduled time and the current time. If the remaining maximum available charging time exceeds the remaining charging time, the battery system uses a gentler charging current. This gentler charging current reduces the heat generated by the battery during charging, thereby reducing thermal stress and minimizing damage caused by high temperatures. Furthermore, this gentler charging method helps slow down the chemical aging of the battery, extending its cycle life.

[0051] If the user has no plans to use the vehicle, then charge it using the existing charging method.

[0052] In one possible implementation, when a user has a car booking plan, the user sets a reservation time through a mobile app, and the vehicle then obtains the reservation time from the mobile app via the network.

[0053] In one possible embodiment, the charging current is determined as follows:

[0054] Charging current = BMS requested charging current * (remaining charging time ÷ remaining maximum available charging time). This method dynamically adjusts the charging current to match the remaining charging time and remaining maximum available charging time. This helps to achieve a gentler charging method without affecting the user's vehicle use, thereby extending the lifespan of the power battery.

[0055] Furthermore, low temperature is a key factor affecting the lifespan and performance of power batteries. Taking lithium batteries as an example, low temperatures significantly weaken their efficiency and prolong charging time. This not only reduces user experience but also hinders the widespread adoption of electric vehicles. Additionally, the health of lithium batteries exposed to prolonged low temperatures is significantly impacted. Therefore, maintaining power batteries at their optimal operating temperature has become a crucial issue that the industry must address. Currently, many electric vehicles employ a basic strategy of heating the power battery before AC charging at low temperatures, or using simple thresholds to determine when to enter a simultaneous charging and heating mode. However, such simple designs may fail at extreme low temperatures, causing repeated fluctuations in battery temperature, resulting in charging interruptions or continuous heating. This negatively impacts the battery's health and creates a poor charging and driving experience for users.

[0056] To avoid the adverse effects of low temperatures on the power battery, such as Figure 2 As shown, the vehicle can be configured with the following multiple modes:

[0057] Mode 1: No charging and no heating mode.

[0058] Mode 2: No charging and heating mode.

[0059] Mode 3: Heating while charging.

[0060] Mode 4: Charging without heating mode.

[0061] In one possible embodiment, the condition for the vehicle to enter the charging and heating mode (i.e., mode three) from the initial state or non-charging and heating mode (i.e., mode two) is... Figure 2 Condition 5) is:

[0062] When there is no heating circuit fault and no heating prohibition fault occurs, and the minimum battery cell temperature is determined to be greater than or equal to the lower charging 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 simultaneous charging and heating threshold, the vehicle enters the simultaneous charging and heating mode. Here, CAL1 is the first preset value; the simultaneous charging and heating threshold is determined based on the current battery system voltage and PTC internal resistance. Because this simultaneous charging and heating threshold is a dynamic value, the system's adaptability is significantly improved. By monitoring the current battery system voltage and PTC internal resistance in real time, the system can intelligently adjust the simultaneous charging and heating threshold, thereby maximizing the heating capacity of the PTC (positive temperature coefficient thermistor).

[0063] In one possible embodiment, the condition for the vehicle to switch from the charging and non-heating mode (i.e., mode four) to the charging and heating mode (i.e., mode three) is:

[0064] When there is no heating circuit fault and no heating prohibition fault 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 temperature + CAL1. At the same time, the charging capacity of the external charging device is greater than the sum of the battery's allowable charging capacity and the charging-while-heating threshold.

[0065] In one possible embodiment, the method for determining the simultaneous charging and heating threshold is as follows:

[0066] The threshold for simultaneous charging and heating is calculated as: current battery system voltage ÷ PTC internal resistance.

[0067] This method designs the simultaneous charging and heating threshold as a dynamic value, precisely controlling it even under extreme low-temperature conditions to avoid repeated fluctuations in battery temperature. This precise control not only ensures smooth charging but also effectively prevents charging interruptions or continuous heating caused by temperature fluctuations, thus protecting the health of the power battery. Furthermore, it reduces the number of calibration tests. Previously, engineers needed to perform numerous calibration tests to ensure system stability under various conditions. Now, because the system can dynamically adjust the simultaneous charging and heating threshold and maintain stable battery temperature, the number and complexity of these tests are significantly reduced, improving development efficiency and lowering costs. Moreover, by dynamically adjusting the simultaneous charging and heating threshold in the entry conditions of the simultaneous charging and heating mode based on the real-time current battery system voltage, it maximizes the use of the PTC to heat the power battery, increasing the charging rate, while preventing excessive current from flowing into the PTC, which could prevent charging at the power battery's maximum capacity and thus affect the charging rate.

[0068] like Figure 2 As shown, in one possible embodiment, when the vehicle is in the charging and heating mode (i.e., mode three) or the initial state, under any of the following conditions (i.e. Figure 2 When condition 6) is met, the charging and non-heating mode (i.e., mode four) is entered.

[0069] Condition a: The minimum temperature of a single battery cell is greater than or equal to the heating start temperature + CAL1.

[0070] Condition b: The maximum temperature of a single battery cell is greater than or equal to the cooling start temperature.

[0071] Condition c: The charging capacity of the power battery is greater than the charging capacity of the external charging equipment.

[0072] The initial state is the first state after the external charging device has been connected and the charging initialization process has been completed (i.e., ...). Figure 2 (Condition 1) Under specific conditions, the vehicle can intelligently switch from a charging-while-heating mode to a charging-without-heating mode. This helps avoid unnecessary heating operations when the battery temperature is already high enough or the external charging equipment's charging capacity is insufficient. This strategy helps protect the health of the power battery and improves charging efficiency and safety. Simultaneously, this strategy also considers the vehicle's initial state, ensuring that after connecting to the external charging equipment and completing the initialization process, the vehicle can correctly enter the corresponding charging mode.

[0073] like Figure 2As shown, in one possible embodiment, the conditions under which the vehicle transitions from the initial state and the non-charging and non-heating mode (i.e., mode one) to the non-charging and heating mode (i.e., mode two) are as follows: Figure 2 Condition 3) is:

[0074] When there is no heating circuit fault and no fault prohibiting heating, the minimum temperature of a single battery cell is less than the lower charging limit temperature.

[0075] like Figure 2 As shown, in one possible embodiment, the condition for the vehicle to switch from the charging and heating mode (i.e., mode three) to the non-charging and heating mode (i.e., mode two) is:

[0076] When there is no heating circuit fault and no fault prohibiting heating, the minimum temperature of the battery cell drops below the lower charging limit temperature.

[0077] like Figure 2 As shown, in one possible embodiment, the conditions for the vehicle to switch from a non-charging and heating mode (i.e., mode two) to a charging and non-heating mode (i.e., mode four) are as follows: Figure 2 Condition 4) is:

[0078] When there is no heating circuit fault and no heating prohibition fault occurs, the vehicle can safely and effectively switch from heating mode to charging mode when the minimum temperature of a single battery cell is greater than or equal to the lower charging limit temperature + 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 is greater than or equal to the cooling activation temperature; where CAL2 is a 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 charging limit temperature + CAL2) and the charging capacity of the external charging device does not exceed the maximum allowable charging capacity of the power battery, the vehicle can switch from heating mode to charging mode. Furthermore, when the power battery temperature reaches or exceeds the cooling activation temperature, the vehicle is also allowed to enter charging mode without heating to prevent the power battery from overheating. This intelligent switching mechanism helps protect the health of the power battery and improves charging efficiency and safety.

[0079] In this embodiment, CAL1 and CAL2 are both calibration values.

[0080] like Figure 2 As shown, in one possible embodiment, the conditions under which the vehicle enters a non-charging and non-heating mode (i.e., mode one) are as follows (i.e. Figure 2 Condition 1) is:

[0081] When the minimum temperature of a single battery cell falls below the lower charging limit and a preset fault occurs, the vehicle will automatically enter a no-charging, no-heating mode. This is a safety protection measure designed to prevent charging or heating the battery under adverse conditions, thereby avoiding potential battery damage or safety accidents. By promptly entering the no-charging, no-heating mode, the vehicle can ensure a safe state in case of a fault, awaiting further repair or inspection.

[0082] like Figure 3 As shown in the embodiments of this 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, which, when called by the controller 2, can execute the steps of the charging control method for the power battery as described in the embodiments of this application.

[0083] In this embodiment of the application, a vehicle employs the power battery charging control system described in this embodiment of the application.

[0084] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A charge control method of a power battery, characterized by, The method comprises the following steps: Obtaining a reservation time for using the vehicle; Determining a remaining charging time and a remaining maximum available charging time, wherein the remaining charging time is the time required for charging the power battery from the current power to full power, and the remaining maximum available charging time is equal to the reservation time for using the vehicle minus the current time; When it is determined that the remaining maximum available charging time is greater than the remaining charging time, dynamically adjusting a charging current based on a BMS requested charging current, the remaining charging time and the remaining maximum available charging time, wherein the charging current is less than the BMS requested charging current; Performing charging control based on the charging current; The vehicle has a side charging and heating mode, and the vehicle enters the side charging and heating mode when the following conditions are met: When there is no heating loop fault and no fault of prohibiting heating, and when it is determined that the minimum value of the battery cell temperature is greater than or equal to the lower limit temperature of charging and less than the heating opening temperature + CAL1, and the charging capacity of the external charging device is greater than the sum of the allowed charging capacity of the power battery and the side charging and heating threshold, the vehicle enters the side charging and heating mode; Wherein, CAL1 is a first preset value; and the side charging and heating threshold is determined according to the current battery system voltage and the PTC internal resistance.

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

3. The charging control method of a power battery according to claim 2, characterized in that, The determination method of the side charging and heating threshold is as follows: Side charging and heating threshold = current battery system voltage ÷ PTC internal resistance.

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

5. The charging control method of a power battery according to claim 4, characterized in that, The vehicle also has a non-charging and non-heating mode, and enters the non-charging and non-heating mode when the following condition is met: The minimum value of the battery cell temperature is less than the lower limit temperature of charging and a preset fault occurs; The preset fault includes at least one of a heating loop fault and a fault of prohibiting heating.

6. The charging control method of a power battery according to claim 5, characterized in that, The vehicle also has a non-charging and heating mode, and enters the non-charging and heating mode from the non-charging and non-heating mode or the initial state when the following condition is met: When there is no heating loop fault and no fault of prohibiting heating, the minimum value of the battery cell temperature is less than the lower limit temperature of charging.

7. The charging control method of a power battery according to claim 6, characterized in that, The vehicle enters the charging and non-heating mode from the non-charging and heating mode when the following conditions are met: 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 allowed charging capacity of the power battery; Or Tmax≥ cooling opening temperature; Wherein, CAL2 is a second preset value.

8. A charge control system for a power cell, characterized by It comprises: A memory (1) for storing a computer readable program; A controller (2) for calling the computer readable program to execute the steps of the charging control method of the power battery according to any one of claims 1 to 7.

9. A vehicle characterized by comprising: A charging control system for a power battery as claimed in claim 8.

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