Disclosure of Invention
In order to solve at least one of the problems in the charging equalization technology for the power battery in the related art, embodiments of the present application provide a power battery equalizing charging method, apparatus, control device and storage medium. The technical scheme is as follows:
in one aspect, a power battery equalizing charge method is provided, and the method comprises the following steps:
determining a first voltage difference value between a first battery cell and a second battery cell of the power battery, wherein the first battery cell is the battery cell with the highest current voltage, and the second battery cell is the battery cell with the lowest current voltage;
when the first voltage difference value is larger than a target voltage difference value, controlling the first battery cell to discharge;
determining a second voltage difference between the voltage of the first cell and a first target voltage;
adjusting a charging current based on the second voltage difference value;
and charging the power battery based on the adjusted charging current.
In a possible embodiment, the adjusting the charging current based on the second voltage difference value includes:
inputting the second voltage difference value into a proportional-integral controller, and performing proportional-integral operation by the proportional-integral controller based on the second voltage difference value to obtain a charging current adjustment value;
adjusting the charging current based on the charging current adjustment value.
In a possible embodiment, the controlling the first cell to discharge when the first voltage difference is greater than a target voltage difference includes:
the first battery cell is connected with an equalizing circuit for discharging in parallel, and the equalizing circuit comprises a switch and a shunt resistor;
and when the first voltage difference value is larger than the target voltage difference value, controlling the switch to be closed, so that the first battery cell is discharged.
In one possible embodiment, the method further comprises:
and when the power battery is determined to meet the target charging condition, executing the process of adjusting the charging current within the maximum allowable time period of equalization.
In one possible embodiment, the power battery meeting the target charging condition is: the residual electric quantity of the power battery is higher than at least one of the first target electric quantity and the voltage of the first battery cell is higher than the second target voltage.
In one aspect, a power battery equalizing charge device is provided, including:
the first voltage difference value determining module is used for determining a first voltage difference value between a first battery cell and a second battery cell of the power battery, wherein the first battery cell is the battery cell with the highest current voltage, and the second battery cell is the battery cell with the lowest current voltage;
the control module is used for controlling the first battery cell to discharge when the first voltage difference value is larger than a target voltage difference value;
a second voltage difference determination module, configured to determine a second voltage difference between the voltage of the first battery cell and a first target voltage;
the adjusting module is used for adjusting the charging current based on the second voltage difference value;
and the charging module is used for charging the power battery based on the adjusted charging current.
In a possible implementation, the adjusting module includes:
the operation unit is used for inputting the second voltage difference value into a proportional-integral controller, and the proportional-integral controller performs proportional-integral operation based on the second voltage difference value to obtain a charging current adjustment value;
and the adjusting unit is used for adjusting the charging current based on the charging current adjusting value.
In one possible embodiment, the first battery cell is connected in parallel with an equalizing circuit for discharging, where the equalizing circuit includes a switch and a shunt resistor;
the control module is further configured to control the switch to be closed when the first voltage difference is greater than the target voltage difference, so that the first cell is discharged.
In a possible embodiment, the apparatus further comprises:
and the execution module is used for executing the process of adjusting the charging current within the maximum allowable time length of equalization when the power battery is determined to meet the target charging condition.
In one possible embodiment, the power battery meeting the target charging condition is: the residual electric quantity of the power battery is higher than at least one of the first target electric quantity and the voltage of the first battery cell is higher than the second target voltage.
In one aspect, a control device is provided, which includes one or more processors and one or more memories, where at least one program code is stored in the one or more memories, and loaded into and executed by the one or more processors to implement the operations performed by the power battery equalizing charging method.
In one aspect, a storage medium is provided, and at least one program code is stored in the storage medium, and is loaded and executed by a processor to implement the operations performed by the power battery equalizing charging method.
The technical scheme provided by the embodiment of the application has the beneficial effects that: according to the equalizing charge method of the power battery provided by the embodiment of the application, the control device can determine a first voltage difference value between a first battery cell with the highest voltage and a second battery cell with the lowest voltage in the power battery, control the first battery cell to discharge when the first voltage difference value is larger than a target voltage difference value, adjust the charge current based on a second voltage difference value between the voltage of the first battery cell and the first target voltage, ensure that the first battery cell is not overcharged, continuously charge the second battery cell, reduce the first voltage difference value between the first battery cell and the second battery cell, and prolong the service life of the power battery.
Detailed Description
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
The power battery comprises at least two battery cores, and the battery cores are connected in series or in parallel, or connected in series and then in parallel, or connected in parallel and then in series. This may cause a problem that the charging degrees of the respective cells are different during charging, which is referred to as a difference in charging uniformity. That is, it may occur that the voltage of some cells is greater than that of other cells during charging, that is, a first cell with the highest voltage and a second cell with the lowest voltage are present. At this time, if the charging is stopped when the first battery cell is full, the first battery cell is full and the second battery cell is not full; if charging is to be continued while the first cell is full, so that the second cell is also full, overcharging of the first cell occurs when both the second cells are full.
In this embodiment of the application, the first battery cell refers to a battery cell with the highest voltage in the current power battery, or all battery cells with voltages greater than a first preset value; the second battery cell is a battery cell with the lowest voltage in the current power battery, or all battery cells with voltages lower than a second preset value.
The power battery charging method of the embodiment of the application adopts a proportional-integral control principle to control the consistency difference between the battery cores during charging, controls the voltage of each battery core to be basically consistent under the condition that each battery core is not overcharged, and eliminates the charging consistency difference.
Fig. 1 is a power battery equalizing charge method provided in an embodiment of the present application, and with reference to fig. 1, the method includes:
101. determining a first voltage difference value between a first battery cell and a second battery cell of the power battery, wherein the first battery cell is the battery cell with the highest current voltage, and the second battery cell is the battery cell with the lowest current voltage.
102. And when the first voltage difference value is larger than the target voltage difference value, controlling the first battery cell to discharge.
103. A second voltage difference between the voltage of the first cell and the first target voltage is determined.
104. The charging current is adjusted based on the second voltage difference value.
105. And charging the power battery based on the adjusted charging current.
According to the equalizing charge method of the power battery provided by the embodiment of the application, the control device can determine a first voltage difference value between a first battery cell with the highest voltage and a second battery cell with the lowest voltage in the power battery, control the first battery cell to discharge when the first voltage difference value is larger than a target voltage difference value, adjust the charge current based on a second voltage difference value between the voltage of the first battery cell and the first target voltage, ensure that the first battery cell is not overcharged, continuously charge the second battery cell, reduce the first voltage difference value between the first battery cell and the second battery cell, and prolong the service life of the power battery.
In one possible embodiment, adjusting the charging current based on the second voltage difference value includes:
and inputting the second voltage difference value into a proportional-integral controller, and performing proportional-integral operation by the proportional-integral controller based on the second voltage difference value to obtain a charging current adjustment value.
The charging current is adjusted based on the charging current adjustment value.
In one possible embodiment, when the first voltage difference is greater than the target voltage difference, controlling the first cell to discharge includes:
the first battery core is connected in parallel with an equalizing circuit used for discharging, and the equalizing circuit comprises a switch and a shunt resistor.
And when the first voltage difference value is larger than the target voltage difference value, the control switch is closed, so that the first battery cell is discharged.
In one possible embodiment, the method further comprises:
and when the power battery is determined to meet the target charging condition, executing the process of adjusting the charging current within the maximum allowable equalizing time period.
In one possible embodiment, the power battery meeting the target charging condition means that: the residual electric quantity of the power battery is higher than at least one of the first target electric quantity and the voltage of the first battery cell is higher than the second target voltage.
All the above optional technical solutions may be combined arbitrarily to form the optional embodiments of the present disclosure, and are not described herein again.
Fig. 2 is a flowchart of a method for equalizing charge of a power battery according to an embodiment of the present disclosure, fig. 3 is a logic flowchart of a method for equalizing charge of a power battery according to an embodiment of the present disclosure, fig. 4 is a logic flowchart of a method for equalizing charge of a power battery according to an embodiment of the present disclosure, with reference to fig. 2, fig. 3, and fig. 4, the method includes:
201. the control device determines whether the power battery meets the target charging condition and executes step 202 and 205 within the maximum allowable time period for equalization when the power battery meets the target charging condition.
Wherein, the power battery meeting the target charging condition means that: the method comprises the steps that the residual electric quantity of the power battery is higher than at least one of a first target electric quantity and the voltage of a first battery cell is higher than a second target voltage, the first battery cell is the battery cell with the highest current voltage, the maximum allowable equalization time length is the longest time length for executing the power battery equalization charging method provided by the embodiment of the application, when the power battery meets the target charging condition, the control equipment can start timing and execute the power battery equalization charging method provided by the embodiment of the application, and when the equalization charging time length recorded by the control equipment reaches the maximum allowable equalization time length, the charging operation of the power battery is stopped.
In one possible embodiment, the control device may obtain the voltage of each cell in the power battery, and use the cell with the highest voltage as the first cell.
In a possible implementation manner, the control device may acquire a State of charge (SOC) of the power battery, and the specific acquisition method may adopt an open-circuit voltage method, an ampere-hour integration method, an internal resistance method, an extended kalman filter algorithm, a neural network algorithm, and the like, and of course, multiple methods may also be used in combination, which is not limited in this embodiment of the present application.
It should be noted that, the first target electric quantity may be set according to actual needs, and for example, may be set to 95%, that is, the control device starts to execute the equalizing charge method for the power battery provided in the embodiment of the present application only when the electric quantity of the whole power battery reaches 95%, in other words, when the electric quantity of the power battery reaches 95%, which means that the charging phase of the power battery has reached the end of charging, the equalizing charge method for the power battery provided in the embodiment of the present application is executed at the end of charging, which may prevent situations that the first battery cell is overcharged and the second battery cell is not fully charged. Of course, the first target electric quantity may also be set to any value according to an actual situation, which is not limited in the embodiment of the present application.
The second target voltage may also be set according to actual needs, where the second target voltage may represent a voltage when the first battery cell is fully charged, and when the voltage of the first battery cell reaches the second target voltage, the control device may determine that the first battery cell is fully charged.
In a possible implementation manner, when the remaining power of the power battery is higher than the first target power or the voltage of the first battery cell is higher than the second target voltage, the control device may execute the equalizing charging method for the power battery provided by the embodiment of the present application. Of course, the control device may also execute the equalizing charge method for the power battery provided in the embodiment of the present application when the remaining power of the power battery is higher than the first target power and the voltage of the first battery cell is higher than the second target voltage. The embodiments of the present disclosure do not limit this.
The maximum allowable equalizing time length is the longest time for the control device to execute the equalizing charging method for the power battery provided by the embodiment of the application. Setting the maximum allowable time length of the equalization can avoid the situation that the second battery cell cannot be fully charged all the time under certain conditions, so that the first battery cell is continuously discharged or charged, and the whole charging time is too long. The equalization maximum allowable time period may be set in advance by the user, and if the equalization maximum allowable time period is not set in advance by the user, the control apparatus may directly assume a default value as the equalization maximum allowable time period, for example, 2 hours.
202. The control device determines a first voltage difference value between a first battery cell and a second battery cell of the power battery, the second battery cell is the battery cell with the lowest current voltage, and when the first voltage difference value is larger than a target voltage difference value, the control device controls the first battery cell to discharge.
In one possible embodiment, the control device may obtain a first voltage difference between a first cell with the highest voltage and a second cell with the lowest voltage in the power battery, where the first voltage difference reflects a situation of voltage imbalance between the cells in the power battery. When the first voltage difference is greater than the target voltage difference, the control device may control the first battery cell to discharge, so as to avoid overcharging of the first battery cell.
As shown in fig. 5, each battery cell in the power battery may be connected in parallel with an equalizing circuit for discharging, where the equalizing circuit includes a switch and a shunt resistor. When the first voltage difference is greater than the target voltage difference, the control device may control the switch to be closed, so that the first battery cell is discharged.
Specifically, when the control device controls the switch to be closed, the equalizing circuit and the first battery cell form a closed loop in which the discharge current I of the first battery cell is present3If the voltage of the first cell is recorded as UmaxThe resistance of the shunt resistor is denoted as R0According to ohm's law, I can be obtained3=Umax/R0If the charging current is denoted as I, the charging current is divided into a current I flowing through the shunt resistor after the switch is closed1And a current I flowing through the first cell2If the voltage of the first cell U ismaxHigher, indicating higher charge in the first cell, then corresponding I3The larger, when I3>I2In this case, the energy released by the discharge of the first cell is converted into heat energy by the shunt resistor and consumed, so that the voltage of the first cell is reduced, and when the voltage of the first cell is reduced, I is caused3And then decreases until I3=I2In this case, the voltage of the first cell does not rise nor decrease, and the current flowing through the first cell is 0, and the first cell is not in a discharge state nor in a charge state. The above description is in UmaxHigher, if U is illustrated as an examplemaxLower, i.e. I3<I2When the first cell is low, the first cell is actually I3-I2Until I is charged3=I2And when the first battery cell stops charging.
Of course, after the control device obtains the voltage of each electric core in the power battery, the control device may also calculate a voltage difference between each electric core, and when the voltage difference between any two electric cores is greater than the target voltage difference, control the electric core with higher voltage to discharge so as to ensure that the electric core with higher voltage is not overcharged, and the electric core with lower voltage may continue to be charged.
203. The control device determines a second voltage difference between the voltage of the first cell and the first target voltage.
In one possible embodiment, the control device may calculate, in real time, a second voltage difference between the voltage of the first cell and a first target voltage, where the first target voltage is a voltage of the first cell desired by the control device. The control device may store a correspondence between the first voltage difference value and the first target voltage, and when the control device acquires the first voltage difference value, the control device may determine the corresponding first target voltage based on the correspondence between the first voltage difference value and the first target voltage.
204. And the control equipment inputs the second voltage difference value into the proportional-integral controller, and the proportional-integral controller performs proportional-integral operation based on the second voltage difference value to obtain a charging current adjustment value. The charging current is adjusted based on the charging current adjustment value.
In one possible implementation, the proportional-integral controller may calculate the second voltage difference value based on equation (1) to obtain the charging current adjustment value.
ΔI=PI(ΔV)=Kp×ΔV+Ki∫0 tΔVdt (1)
Wherein Δ I is a charging current adjustment value, Δ V is a second voltage difference value, KpIs a proportionality coefficient, KiIs an integral coefficientAnd t is a control time duration.
In one possible embodiment, the control device may adjust the charging current based on a charging current adjustment value, e.g., the present charging current is I1If the charging current is adjusted by Δ I and the adjusted charging current is I, I ═ I can be obtained1+ Δ I, the control device may then send the adjusted charging current to the charge controller, which adjusts the charging current to I. Of course, the control device may also adjust the charging current to I by itself, which may be specifically implemented by adjusting a total resistance in the circuit, and the embodiment of the present application does not limit the manner in which the control device controls the charging current.
205. The control device charges the power battery based on the adjusted charging current.
For ease of understanding, reference is again made to FIG. 5 as an example, when I3=I2When the charging current is adjusted by the control device, the charging current I in fig. 5 is actually adjusted, that is, the charging current I is adjusted at the same time1And current I2Due to the resistance R of the shunt resistor0Not changed, then at this instant I3Also unchanged, if the control device decreases the charging current I, corresponding to I2Will also decrease, then I will be at this time3>I2When the first battery cell starts to discharge, the voltage of the first battery cell is slowly reduced in the discharging process, that is, the second voltage difference between the voltage of the first battery cell and the first target voltage is also slowly reduced, and accordingly, the proportional-integral controller also controls the charging current to be slowly reduced based on the slowly reduced second voltage difference. When the second voltage difference is less than the target threshold, the control device may stop controlling the charging current when I3=I2In this case, the voltage of the first cell is stabilized near the first target voltage. Meanwhile, the second battery cell with lower electric quantity does not stop charging, but continues to be charged by the adjusted charging current, and when the voltage of the second battery cell reaches the first target voltage, the control is carried outThe device may stop charging the power battery when the power battery is fully charged, or stop charging the power battery when the charging time reaches the maximum allowable time for equalization, as described in step 201, or stop charging the power battery when the second voltage difference is smaller than the target voltage difference and the charging time reaches the maximum allowable time for equalization, which is not limited in the embodiment of the present application.
According to the equalizing charge method of the power battery provided by the embodiment of the application, when the control equipment detects that the residual electric quantity of the power battery is higher than the first target electric quantity or the voltage of the first battery cell is higher than the second target voltage, the control equipment detects the first voltage difference value between the first battery cell and the second battery cell, when the first voltage difference value is larger than the target voltage difference value, the voltage of the first battery cell is controlled to be close to the first target voltage through the proportional-integral controller by means of the equalizing circuit, meanwhile, the second battery cell is enabled to keep a continuous charge state, the first battery cell can be prevented from being overcharged, the first voltage difference value between the first battery cell and the second battery cell can be gradually reduced, and the service life of the power battery is prolonged. In addition, a user can set a maximum allowable equalization duration in advance to ensure that the charging process of the power battery cannot be infinitely prolonged and save electric energy.
The following describes the beneficial effects of the embodiments of the present application with a specific embodiment:
the maximum allowable equalization time period in this embodiment is set by the user, and the value thereof is 2 hours, the target voltage difference is 0.1V, and the first target voltage is 4.2V. As shown in fig. 6, when the control device detects that the SOC of the power battery is 95%, at this time, the voltage of the first battery cell is 4.211V, and the voltage of the second battery cell is 4.025V, a first voltage difference between the first battery cell and the second battery cell is 0.186V, and the first voltage difference is greater than a target voltage difference, the control device controls the first battery cell to discharge, so that the voltage of the first battery cell is stabilized at about 4.2V.
Fig. 7 is a schematic structural diagram of an equalizing charging device for power batteries according to an embodiment of the present application, where the equalizing charging device includes: a first voltage difference value determining module 701, a control module 702, a second voltage difference value determining module 703, an adjusting module 704, and a charging module 705.
A first voltage difference determining module 701 is configured to determine a first voltage difference between a first cell and a second cell of the power battery, where the first cell is a cell with the highest current voltage, and the second cell is a cell with the lowest current voltage.
The control module 702 is configured to control the first cell to discharge when the first voltage difference is greater than the target voltage difference.
A second voltage difference determining module 703 is configured to determine a second voltage difference between the voltage of the first battery cell and the first target voltage.
An adjusting module 704, configured to adjust the charging current based on the second voltage difference value.
And a charging module 705 for charging the power battery based on the adjusted charging current.
In one possible embodiment, the adjustment module includes:
and the operation unit is used for inputting the second voltage difference value into the proportional-integral controller, and the proportional-integral controller performs proportional-integral operation based on the second voltage difference value to obtain the charging current adjustment value.
And the adjusting unit is used for adjusting the charging current based on the charging current adjusting value.
In one possible embodiment, the first battery cell is connected in parallel with an equalizing circuit for discharging, and the equalizing circuit includes a switch and a shunt resistor.
The control module is further configured to control the switch to close when the first voltage difference is greater than the target voltage difference, so that the first battery cell discharges.
In one possible embodiment, the apparatus further comprises:
and the execution module is used for executing the process of adjusting the charging current within the maximum allowable time length of the balance when the power battery is determined to meet the target charging condition.
In one possible embodiment, the power battery meeting the target charging condition means that: the residual electric quantity of the power battery is higher than at least one of the first target electric quantity and the voltage of the first battery cell is higher than the second target voltage.
Through the equalizing charge device for the power battery provided by the embodiment of the application, when the control equipment detects that the residual electric quantity of the power battery is higher than the first target electric quantity or the voltage of the first battery cell is higher than the second target voltage, the control equipment detects the first voltage difference value between the first battery cell and the second battery cell, when the first voltage difference value is larger than the target voltage difference value, the voltage of the first battery cell is controlled to be close to the first target voltage through the proportional-integral controller by means of the equalizing circuit, meanwhile, the second battery cell is enabled to keep the continuous charge state, the overcharge of the first battery cell can be prevented, the first voltage difference value between the first battery cell and the second battery cell can be gradually reduced, and the service life of the power battery is prolonged. In addition, a user can set a maximum allowable equalization duration in advance to ensure that the charging process of the power battery cannot be infinitely prolonged and save electric energy.
Fig. 8 is a schematic structural diagram of a control device 800 according to an embodiment of the present invention, where the control device 800 may generate a relatively large difference due to different configurations or performances, and may include one or more processors (CPUs) 801 and one or more memories 802, where the memory 802 stores at least one program code, and the at least one program code is loaded and executed by the processors 801 to implement the method for equalizing and charging a power battery according to the above-described method embodiments. Of course, the control device may also have components such as a wired or wireless network interface, a keyboard, and an input/output interface, so as to perform input/output, and the control device may also include other components for implementing the functions of the device, which are not described herein again.
In an exemplary embodiment, there is also provided a storage medium, such as a memory, including program code executable by a processor in a control device or a server to perform the power cell equalizing charge method in the above embodiments. For example, the storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a Compact Disc Read-Only Memory (CD-ROM), a magnetic tape, a floppy disk, an optical data storage device, and the like.
In embodiments of the present invention, it should be understood that the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated.
The invention is not to be considered as limited to the particular embodiments shown and described, but is to be understood that various modifications, equivalents, improvements and the like can be made without departing from the spirit and scope of the invention.