JP5595981B2 - Battery control method and battery control system - Google Patents

Description

  The present invention relates to a battery control method and a battery control system that can appropriately raise the temperature of a battery whose output power is reduced as the temperature decreases in a cold region or the like.

  For example, a lithium ion battery, which is a secondary battery used in a hybrid vehicle, an electric vehicle, or the like, has an output power when the temperature is −20 ° C. is about 1/10 of the output power when the temperature is 25 ° C. Decrease to a degree. Considering this decrease in output power, the number of batteries that can be reliably started even at low temperatures is set, so the number of batteries installed in the vehicle increases, increasing the battery mounting space and the battery This has led to an increase in weight.

Therefore, the conventional technology described in Patent Document 1 includes an electric device (bidirectional DC / DC converter, boost converter, motor, etc.) capable of operating charging / discharging of a battery mounted on a vehicle, and the electric device. There is disclosed a battery temperature increase control device including selection means for performing battery temperature increase control by selecting an appropriate electric device and charging and discharging the battery. This temperature increase control device forcibly charges and discharges the battery, thereby increasing the temperature by causing Joule heat generated by the internal resistance of the battery to generate heat from the inside of the battery and recovering the output power of the battery.
Further, in the prior art described in Patent Document 2 and Patent Document 3, when the battery is at a low temperature, Joule heat is generated by alternately and periodically charging and discharging the battery to raise the temperature of the battery 2. A control device for a secondary battery is disclosed.

JP 2010-93483 A JP 2007-28702 A JP 2007-12568 A

The “internal resistance” used for internal heat generation of the battery is “electron resistance” that is resistance when electrons flow through the positive and negative electrode collectors, and resistance when ions flow through the electrolyte. `` Liquid resistance '', `` Reaction resistance '' which is the resistance when ions enter and exit the active material, and resistance when ions in the active material diffuse into the active material and when ions move in the electrolyte And “diffusion resistance”. And “Reaction resistance” and “Diffusion resistance” have their own capacitance components, etc., and the impedance changes depending on the frequency, and the value is about several mΩ. It is difficult to.
Therefore, in the prior art described in Patent Document 1, the “internal resistance” is not calculated, and the charge / discharge amplitude for raising the temperature of the battery is determined using a map created based on experimental data, simulation, or the like. The charge / discharge cycle is obtained from the battery temperature and the amplitude. Therefore, it is not mentioned that “internal resistance” includes “electronic resistance”, “liquid resistance”, “reaction resistance”, and “diffusion resistance”. Moreover, although the battery mounted in a hybrid vehicle or an electric vehicle is used in the form of a battery pack in which a plurality of batteries are connected in series, the output voltage and the internal resistance are different for each battery. Further, both the output voltage and the internal resistance vary individually depending on the deterioration state of the battery. Therefore, even if the temperature rises uniformly with the amplitude and cycle obtained using the battery temperature, it is thought that each battery can be heated appropriately, but not optimally. .
Similarly to Patent Document 1, Patent Document 2 and Patent Document 3 do not calculate “internal resistance”, and charge and discharge using a motor or a boost converter to raise the temperature. However, it does not mention that “internal resistance” includes “electronic resistance”, “liquid resistance”, “reaction resistance”, and “diffusion resistance”, and does not require “internal resistance”. Although it is possible to raise the temperature of the battery as it is, it is thought that the temperature cannot be raised optimally.
The present invention was devised in view of the above points, and battery control that can appropriately determine the internal resistance of each battery and appropriately raise the temperature of the battery using the determined internal resistance. It is an object to provide a method and a battery control system.

In order to solve the above problems, the battery control method according to the present invention takes the following means.
First, the first aspect of the present invention is a battery control method for charging and discharging a target battery and raising the temperature of the battery by internal heat generation utilizing the internal resistance of the battery.
The internal resistance can follow a first resistance component, which is a resistance component capable of following an alternating voltage of all frequencies, and an alternating voltage of a frequency equal to or lower than the first frequency, but to an alternating voltage of a frequency higher than the first frequency. A second resistance component, which is a resistance component that cannot be followed, and a resistance component that is capable of following an AC voltage of a second frequency lower than the first frequency but cannot follow an AC voltage having a frequency higher than the second frequency. A third resistance component.
An AC voltage having a first predetermined amplitude set to an internal resistance measurement frequency that is equal to or lower than the first frequency and equal to or higher than the second frequency and two or more different frequencies with respect to the battery. Each internal resistance measurement AC voltage is applied, each AC current that is a follow-up current generated for each applied internal resistance measurement AC voltage is measured, and each internal resistance measurement applied Internal resistance calculation for calculating at least the first resistance component and the second resistance component in the battery based on the AC voltage and each AC current measured corresponding to each AC voltage for measuring the internal resistance. A step, an ambient temperature of the battery, a target battery temperature, the calculated first resistance component and the second resistance component, and the first frequency And a temperature rising frequency set to a frequency equal to or higher than the second frequency and an AC voltage for temperature rising that is an AC voltage having a second predetermined amplitude, and is necessary for temperature rising of the battery. A temperature rising time calculation step for calculating a temperature rising time, which is a long time, and a temperature rising voltage obtained by superimposing the temperature rising AC voltage on a DC voltage corresponding to the output voltage of the battery during the temperature rising time. And a temperature raising step in which the temperature is raised by charging and discharging the battery by applying to the battery.

  According to the first aspect of the invention, in the internal resistance calculation step, the first resistance component (corresponding to electronic resistance and liquid resistance) and the second resistance component (corresponding to reaction resistance) in the internal resistance of the battery are appropriately calculated. be able to. Then, using the calculated internal resistance, it is possible to calculate an appropriate temperature increase time in the temperature increase time calculation step, and it is possible to increase the battery temperature more appropriately to the target battery temperature in the temperature increase step. It is.

Next, 2nd invention of this invention is a battery control method which concerns on the said 1st invention, Comprising: The said battery is comprised as a battery pack by which the plurality was connected in series.
Performing the internal resistance calculating step and the temperature rising time calculating step for each battery, calculating the first resistance component, the second resistance component, and the temperature increasing time for each battery; Before the calculation, a battery average voltage is calculated by dividing the output voltage of the battery pack by the number of batteries connected in series.
Then, in the temperature raising step, for each battery, a specific output voltage that is an output voltage of each battery is measured, and gradually from the specific output voltage over the temperature rising time corresponding to each battery. To set the specific DC voltage reaching the battery average voltage, the temperature rising voltage obtained by superimposing the temperature rising AC voltage on the set specific DC voltage, during the temperature rising time corresponding to each battery, respectively The battery is charged and discharged to increase the temperature.

According to the second aspect of the present invention, when a battery pack in which a plurality of batteries are connected in series is configured, the output voltage and the internal resistance of each battery are different. The temperature can be raised to the target battery temperature.
Furthermore, since the variation in the output voltage of each battery can be flattened to obtain a battery average voltage, the charge / discharge characteristics of a battery pack in which a plurality of batteries are connected in series can be utilized to the maximum.

Next, according to a third aspect of the present invention, there is provided a battery control system that charges and discharges a target battery and raises the temperature of the battery by internal heat generation utilizing the internal resistance of the battery. AC voltage generating means for generating the AC voltage, DC voltage generating means for generating a DC voltage of a predetermined voltage, power supply means for supplying the AC voltage and the DC voltage, and superimposing the AC voltage and the DC voltage Possible voltage superimposing means, alternating current measuring means capable of measuring alternating current, direct current voltage measuring means capable of measuring direct current voltage, temperature measuring means capable of measuring the temperature of the target battery atmosphere, and control means And comprising.
The internal resistance can follow a first resistance component, which is a resistance component capable of following an alternating voltage of all frequencies, and an alternating voltage of a frequency equal to or lower than the first frequency, but to an alternating voltage of a frequency higher than the first frequency. A second resistance component, which is a resistance component that cannot be followed, and a resistance component that is capable of following an AC voltage of a second frequency lower than the first frequency but cannot follow an AC voltage having a frequency higher than the second frequency. A third resistance component.
The control means uses the power supply means and the AC voltage generation means to measure an internal resistance that is a frequency not higher than the first frequency and not lower than the second frequency and not lower than the second frequency. Each of the internal resistance measurement AC voltages, which are AC voltages having a first predetermined amplitude set at a frequency for application, is applied to the battery, and each of the applied AC resistance measurement AC is applied using the AC current measuring means. Each alternating current, which is each follow-up current generated with respect to the voltage, is measured, and each alternating current measured in accordance with each of the applied internal resistance measuring AC voltage and each of the internal resistance measuring voltages. Based on the current, at least the first resistance component and the second resistance component in the battery are calculated.
The control means includes the battery ambient temperature measured using the temperature measurement means, a preset target battery temperature, the calculated first resistance component and the second resistance component, and the first frequency. The temperature of the battery is increased based on a temperature increase frequency that is a frequency equal to or lower than the second frequency and is set to a frequency equal to or higher than the second frequency and an AC voltage having a second predetermined amplitude. Calculate the heating time, which is the required time.
The control means uses the power supply means, the AC voltage generating means, the DC voltage generating means, the voltage superimposing means, and the DC voltage measuring means, and measures the DC voltage measuring means. The temperature rising voltage obtained by superimposing the temperature rising AC voltage on the DC voltage corresponding to the output voltage of the battery is applied to the battery during the temperature rising time to charge and discharge the battery. Warm up.

  According to the third aspect of the present invention, it is possible to appropriately realize a battery control system that can raise the battery temperature more appropriately to the target battery temperature.

Next, 4th invention of this invention is a battery control system which concerns on the said 3rd invention, Comprising: The said battery is comprised as a battery pack with which two or more were connected in series.
The control means calculates the first resistance component, the second resistance component, and the temperature rising time for each battery, measures the output voltage of the battery pack using the DC voltage measuring means, A battery average voltage is calculated by dividing the measured output voltage by the number of batteries connected in series.
The control means measures the specific output voltage, which is the output voltage of each battery, using the DC voltage measuring means when applying the temperature rising voltage to each battery, and the power supply means. And using the AC voltage generating means, the DC voltage generating means, and the voltage superimposing means, for each battery, the specific output voltage is increased over the temperature rising time corresponding to each battery. Is set to a specific DC voltage that gradually reaches the battery average voltage, and the temperature rising voltage obtained by superimposing the temperature rising AC voltage on the set specific DC voltage is set for the temperature rising time corresponding to each battery. In the meantime, the temperature is increased by charging and discharging each battery.

According to the fourth aspect of the invention, it is possible to appropriately realize a battery control system that can raise the temperature of each individual battery to a target battery temperature more appropriately.
Furthermore, it is possible to flatten the variation in the output voltage of each battery to obtain a battery average voltage, and to make maximum use of the charge / discharge characteristics of a battery pack in which a plurality of batteries are connected in series The control system can be realized appropriately.

In the case of the hybrid vehicle 1 as an example, it is a figure explaining the example of the mounting position of the battery pack BP, the control apparatus 20, and the power supply means 30. FIG. (A) is a figure explaining the example of the external appearance of the battery B, and the example of the external appearance of the battery pack BP which connected the some battery B in series, (B) demonstrates the example of the equivalent circuit of the internal resistance of the battery B. It is a figure to do. (A) is a figure explaining the example of the temperature rising voltage which superimposed the AC voltage for temperature rising on battery output voltage (DC voltage), (B) is the temperature of the voltage for temperature rising, and the temperature rising in each frequency It is a graph explaining efficiency of. (A) is a figure explaining the example of a structure of the control apparatus 20, and connection with the battery Bn, (B) is an example of the voltage output circuit 22 containing an alternating voltage generation means, a direct current voltage generation means, and a voltage superimposition means. It is a figure explaining. It is a figure explaining the example of the alternating voltage for internal resistance measurement, and a follow-up current. It is a figure explaining the example of Cole * Cole plot utilized when calculating | requiring internal resistance. 4 is a flowchart illustrating an example of a processing procedure of a control unit 21. (A) is a figure explaining the example of the voltage for temperature rising in the case of charging / discharging the battery Bn which has the higher specific output voltage An than the battery average voltage E, (B) is a characteristic lower than the battery average voltage E It is a figure explaining the example of the voltage for temperature rising in the case of charging / discharging the battery Bm which has the output voltage Am.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. FIG. 1 shows an example of the appearance of a vehicle 1 (hybrid vehicle, electric vehicle, etc.) to which the battery control system of the present invention is applied.

[Mounting position of battery pack BP, control device 20 and power supply means 30 (FIG. 1)]
The battery control system of the present invention includes a control device 20 and power supply means 30, and is mounted at a position adjacent to the battery pack BP on the lower floor of the vehicle 1 as shown in FIG.

● [Battery pack BP, battery B appearance and battery B internal resistance (Fig. 2)]
As shown in FIG. 2, the battery pack BP is configured by connecting a plurality of batteries B in series. The battery B is, for example, a lithium ion secondary battery, and although not shown in the figure, the positive electrode and the negative electrode of adjacent batteries are connected in series by a conductor called a bus bar.
It is known that the output power of the battery pack BP at a temperature of −20 ° C. is reduced to about 1/10 of the output power of the battery pack BP at a temperature of 25 ° C. Therefore, since the battery pack BP is configured by the number of batteries B necessary for ensuring startability at a low temperature such as −20 ° C., the number of the batteries B is large, space is required and the weight is large. It has increased.

In order to reduce the number of batteries B constituting the battery pack BP, it is sufficient that the temperature of the battery B can be raised appropriately.
In order to raise the temperature of the battery B, it is more efficient to generate heat from the inside by Joule heat using the internal resistance of the battery B, rather than applying heat from the outside with a heater or the like.
In order to generate Joule heat, it is only necessary to repeatedly charge and discharge the battery B. However, since the internal resistances of the batteries B have different values, the same frequency and the same amplitude voltage are applied to each battery B. Even if only the time is input, the temperature is raised to different temperatures.
In order to raise the temperature so that the temperature of each battery B becomes the same temperature while using the conventional techniques described in Patent Documents 1 to 3, it is necessary to provide a temperature sensor for each battery B, cost, space, The number of wirings will increase greatly.

The internal resistance of the battery B is as shown in the equivalent circuit of FIG. 2B, and includes an electronic resistance Re, a liquid resistance Rs, a reaction resistance Rct, and a diffusion resistance Zw.
The electronic resistance Re is a resistance when electrons flow through the positive and negative electrode collectors, does not include a capacitance component, is expressed only by the resistance component Re, and can follow all frequencies. Resistance. Note that “followable” means that a current flows in real time with respect to an applied voltage. For example, when a sine AC voltage is applied, a sine AC current is generated although there is a delay time. Point to.
The liquid resistance Rs is a resistance when ions flow in the electrolytic solution, does not include a capacitance component, is expressed only by the resistance component Rs, and is a resistance that can follow all frequencies.
The reaction resistance Rct is a resistance when ions enter and exit the active material, includes a capacitance component, and is represented by a parallel circuit of the resistance component Rr and the capacitance component Cr. The reaction resistance Rct can follow, for example, a frequency of 800 Hz or less (corresponding to the first frequency), but cannot follow a frequency exceeding 800 Hz due to the influence of the capacitive component Cr.
The diffusion resistance Zw is a resistance when ions in the active material diffuse to the back of the active material, and a resistance when ions move in the electrolytic solution, and includes a capacitance component. The diffusion resistor Zw can follow a frequency of 0.5 Hz or less (corresponding to the second frequency), but cannot follow a frequency exceeding 0.5 Hz due to the influence of the capacitance component.
In addition, in the battery B, the place where the temperature is most desired is the entire inside of the battery excluding the electrode part, which is a part having reaction resistance. Therefore, it is preferable to generate Joule heat using reaction resistance.

● [Selecting the frequency of the voltage to be raised when charging the battery B to raise the temperature (Fig. 3)]
Next, with reference to FIG. 3A, an example of the temperature raising voltage applied when the temperature of the battery B is raised will be described.
In order to increase the temperature by charging / discharging the battery B, a temperature increasing voltage obtained by superimposing the temperature increasing AC voltage on the DC voltage having the same voltage as the output voltage of the battery B is applied to the battery B. Thereby, when the voltage for raising temperature is higher than the battery output voltage, the battery B is charged, and when the voltage for raising temperature is lower than the battery output voltage, the battery B is discharged and the battery B can be charged / discharged. .
In the description of the present embodiment, an example in which the amplitude of the AC current for temperature increase is set to ± 50 mV will be described, but the amplitude of the AC current for temperature increase is not limited to ± 50 mV.
Further, the frequency of the AC current for temperature increase is determined as follows.

FIG. 3B is a graph showing the relationship between the frequency of the voltage for raising temperature and the energy / input power used for raising the temperature in the lithium ion battery. From the graph, it can be seen that the temperature can be most efficiently raised when the frequency of the temperature raising voltage is fmx. When the battery B was a lithium ion battery, the frequency fmx was about 400 Hz. This frequency is a frequency that can generate Joule heat using reaction resistance, and is very preferable.
If the frequency of the temperature raising voltage is 400 Hz, Joule heat is generated by the impedance of the internal resistance at this frequency. Therefore, at a frequency of 400 Hz, among the internal resistances, the electronic resistance Re, the liquid resistance Rs, and the reaction resistance Rct generate Joule heat. If these are calculated | required, the temperature rise per unit time from the consumption current of charging / discharging by the alternating current for temperature rise, the impedance of the internal resistance including the electronic resistance Re, the liquid resistance Rs, and the reaction resistance Rct, the specific heat of the battery B, etc. The temperature can be determined.
Furthermore, the temperature increase time can be obtained from the temperature difference between the temperature of the battery B at the start of temperature increase and the target battery temperature.
The temperature of the battery B at the start of temperature rise is detected by a temperature sensor 25 (see FIG. 4A) that is directly attached to the battery B or arranged around the battery B. The target battery temperature may be a previously fixed temperature such as 25 ° C., or may be obtained from the temperature of the battery B at the start of temperature rise, the output voltage of the battery B before temperature rise, or the like. In the present embodiment described below, an example in which the target battery temperature is fixed at 25 ° C. will be described.

[[Configuration of control device 20 and connection state of each battery Bn (FIG. 4)]
Next, the configuration of the control device 20 and the connection between the control device 20, the power supply means 30, and each battery Bn of the battery pack BP will be described with reference to FIG.
The control device 20 includes a control unit 21 such as a CPU, a voltage output circuit 22 including an AC voltage generating unit, a DC voltage generating unit, and a voltage superimposing unit, a current detection circuit 23 including an AC current measuring unit, and a DC voltage measuring unit. A voltage detection circuit 24 and a selection circuit SL are included.
The positive and negative poles of the batteries B1, B2,... Bn are connected to the terminals S1, S2,. Further, the positive electrode and the negative electrode of the battery pack BP in which the batteries B1 to Bn are connected in series by the bus bar Bb are connected to the terminal ST.
Based on the signal from the control means 21, the selection circuit SL sets the + pole and the −pole connected to any one of the terminals S 1, S 2... Sn, ST, the voltage output circuit 22 and the current detection circuit 23. And connected to the voltage detection circuit 24.
Further, a temperature sensor 25 (corresponding to temperature measuring means) for detecting the ambient temperature of the battery pack BP is directly attached to the battery Bn or disposed around the battery pack BP.
The power supply means 30 is a capacitor, a secondary battery, or the like, and accumulates discharged power during the discharging operation of the battery B, and supplies the accumulated power during the charging operation of the battery B. The power supply means 30 is connected to the voltage output circuit 22.

With the above configuration and connection, the control means 21 outputs a control signal to the selection circuit SL to select one of the terminals S1, S2,... Sn, ST, and to the positive electrode and negative electrode of the selected battery. The voltage (AC voltage or DC voltage) generated by the voltage output circuit 22 can be applied using the power from the power supply means 30. The control means 21 can output a control signal to the voltage output circuit 22 to generate DC voltages having various voltage values, and can generate AC voltages having various frequencies and amplitudes. It is possible to generate a voltage in which the generated DC voltage and AC voltage are superimposed. Then, the generated voltage is applied to the positive electrode and the negative electrode of the selected battery.
Further, the control means 21 can detect an alternating current generated between the positive electrode and the negative electrode of the selected battery via the current detection circuit 23.
Further, the control means 21 can detect a DC voltage generated between the positive electrode and the negative electrode of the selected battery via the voltage detection circuit 24.
Further, the control means 21 can detect the ambient temperature of the battery pack BP (or the temperature of the battery Bn) based on the detection signal from the temperature sensor 25.

FIG. 4B shows an example of the voltage output circuit 22.
A diode D1 is connected between the source and drain of the MOS transistor Tr1, and a control signal from the control means 21 is input to the gate of Tr1. The drain of Tr1 is connected to the positive pole of the power supply means 30, and the source of Tr1 is connected to one end of the coil L1.
A diode D2 is connected between the source and drain of the MOS transistor Tr2, and a control signal from the control means 21 is input to the gate of Tr2. The drain of Tr2 is connected to one end of the coil L1, and the source of Tr2 is grounded.
A diode D3 is connected between the source and drain of the MOS transistor Tr3, and a control signal from the control means 21 is input to the gate of Tr3. The drain of Tr3 is connected to the other end of the coil L1, and the source of Tr3 is grounded.
A diode D4 is connected between the source and drain of the MOS transistor Tr4, and a control signal from the control means 21 is input to the gate of Tr4. The drain of Tr4 is connected to one end of the capacitor C1, and the source of Tr4 is connected to the other end of the coil L1.
The other end of the capacitor C1 is grounded, and both ends of the capacitor C1 are connected to the selection circuit SL.

[Processing procedure of control means 21 (FIG. 5)]
Next, the processing procedure of the control means 21 will be described using the flowchart shown in FIG.
The flowchart shown in FIG. 5 is executed, for example, before starting the vehicle 1 or when receiving a start command from a remote controller or the like.
And the process of the control means 21 shown in FIG. 5 is the internal resistance calculation step S100 which calculates | requires internal resistance of each battery B1-Bn, The temperature rising time calculation step S200 which calculates | requires the temperature rising time of each battery B1-Bn, Each battery And a temperature raising step S300 for raising the temperature by charging and discharging B1 to Bn.

In step S110, the control means 21 substitutes 1 for n for specifying any one of the batteries B1 to Bn, and proceeds to step S120.
In step S120, control means 21 outputs a signal for selecting terminal S (n) (in this case, terminal S1) corresponding to battery B (n) (in this case, battery B1) to selection circuit SL. The process proceeds to step S130.
In step S130, the control means 21 controls the voltage output circuit 22 to apply an alternating voltage (f1) having a predetermined amplitude at the frequency f1 to the battery B (n), and generates a detection signal from the current detection circuit 23. Based on this, the tracking current (f1) is measured, and the process proceeds to step S140.
In step S140, the control means 21 controls the voltage output circuit 22 to apply an alternating voltage (f2) having a predetermined amplitude at the frequency f2 to the battery B (n), and generates a detection signal from the current detection circuit 23. Based on this, the follow-up current (f2) is measured, and the process proceeds to step S150.
In step S150, the control means 21 controls the voltage output circuit 22 so as to apply an alternating voltage (f3) having a predetermined amplitude at the frequency f3 to the battery B (n), and to detect the detection signal from the current detection circuit 23. Based on this, the follow-up current (f3) is measured, and the process proceeds to step S160.
In step S160, the control means 21 at least based on the alternating voltage (f1) and the follow-up current (f1), the alternating voltage (f2) and the follow-up current (f2), the alternating voltage (f3) and the follow-up current (f3). Electronic resistance Re, liquid resistance Rs (corresponding to the first resistance component) and reaction resistance Rct (corresponding to the second resistance component) are calculated, and the process proceeds to step S170.

Here, the internal resistance calculation step (particularly, steps S130 to S160) in step S100 will be described in detail with reference to FIGS. In this step, the internal resistance (electronic resistance Re + liquid resistance Rs and reaction resistance Rct) is calculated from a Cole-Cole plot using a so-called AC impedance method. Since the AC impedance method and the Cole / Cole plot are already existing, the outline will be described.
FIG. 6 shows an example of the follow-up current generated when an AC voltage is applied. There is a delay time ΔT in the follow-up current with respect to the applied AC voltage. In addition, the amplitude of the follow-up current is an amplitude corresponding to the impedance of the internal resistance with respect to the amplitude of the applied AC voltage.
In the present embodiment, the frequency of the applied AC voltage (f1) is 800 Hz, the frequency of the AC voltage (f2) is 400 Hz, and the frequency of the AC voltage (f3) is 0.5 Hz. The amplitudes of the alternating voltage (f1) to the alternating voltage (f3) were all ± 20 mV. The frequency of the AC voltage (f1) to AC voltage (f3) corresponds to the internal resistance measurement frequency, and the amplitude of the AC voltage (f1) to AC voltage (f3) corresponds to the first predetermined amplitude.
The position of P (f1) in the Cole / Cole plot shown in FIG. 7 is determined from the delay time ΔT (f1), amplitude (f1), etc. of the follow-up current (f1) with respect to the AC voltage (f1). Similarly, the position of P (f2) is determined with respect to the alternating voltage (f2), and the position of P (f3) is determined with respect to the alternating voltage (f3).
In the Cole / Cole plot shown in FIG. 7, it is known that P (f1), P (f2), and P (f3) are located on an arc (on a semicircle). The real component of the impedance of the electronic resistance Re + liquid resistance Rs and the real component of the impedance of the reaction resistance Rct can be obtained.
In the above example, an example is described in which AC voltages having three different internal resistance measurement frequencies are applied to obtain the internal resistance. However, the present invention is not limited to three, and AC voltages having two or more different frequencies may be used. It is only necessary to apply and obtain the respective follow-up currents.
Further, the alternating voltage (f1) to alternating voltage (f3) can be sufficiently measured by applying about 10 cycles, and can be measured in a relatively short time.
In step S170, the control means 21 determines whether or not the calculation of the internal resistance of all the batteries B (n) has been completed. If the calculation of the internal resistance of all the batteries B (n) has been completed (Yes), the process proceeds to Step SA10. If not (No), n + 1 is substituted into n via Step S180 (next battery B (Preparing (n + 1)) The process returns to step S120.

When the process proceeds to step SA10, the control means 21 outputs a signal for selecting the terminal ST corresponding to the battery pack BP to the selection circuit SL, and the process proceeds to step SA20.
In step SA20, the control means 21 measures the output voltage of the battery pack BP via the terminal ST and the voltage detection circuit 24. Then, the measured output voltage of the battery pack BP is divided by the number of the batteries B1 to Bn constituting the battery pack BP to calculate the battery average voltage, and the process proceeds to Step SA30.
In step SA30, the control means 21 uses the selection circuit SL to connect the batteries B1 to Bn to the voltage detection circuit 24 in order, and measures the specific output voltage (n) that is the output voltage of each of the batteries B1 to Bn. Then, the order of the batteries to be heated is determined, and the process proceeds to step S210. For example, the first is the battery with the highest specific output voltage, the second is the battery with the lowest specific output voltage, the third is the second battery with the specific output voltage from the top, and the fourth is the second battery with the specific output voltage from the bottom. The order is determined so that the specific output voltage becomes high-low-high-low.

In step S210, the control means 21 measures the ambient temperature of the batteries B1 to Bn (the temperature of the batteries B1 to Bn) based on the detection signal from the temperature sensor 25, and calculates the required amount of heat from the ambient temperature and the target battery temperature. Calculate and go to step S220. The target battery temperature may be a fixed temperature such as 25 ° C., or a temperature corresponding to the ambient temperature or the like may be obtained.
In step S220, the control means 21 substitutes 1 for n for specifying any one of the batteries B1 to Bn, and proceeds to step S230.
In step S230, control means 21 outputs a signal for selecting terminal S (n) (in this case, terminal S1) corresponding to battery B (n) (in this case, battery B1) to selection circuit SL. The process proceeds to step S240.
In step S210, the control means 21 calculates the temperature increase time (n) of the battery B (n) from the internal resistance (n) of the battery B (n), the AC voltage for temperature increase, and the necessary heat amount, Proceed to step S250. The AC voltage for temperature increase is, for example, an AC voltage having a frequency of 400 Hz (the most efficient frequency in FIG. 3B) and an amplitude of ± 50 mV (corresponding to the second predetermined amplitude). The frequency of the AC voltage for temperature rise is a frequency that the reaction resistance Rct can follow, and the diffusion resistance Zw cannot follow, is equal to or lower than the first frequency (in this case, 800 Hz) and the second frequency (in this case) , 0.5 Hz) or higher. The internal resistance (n) is the electronic resistance Re, the liquid resistance Rs (first resistance component), and the reaction resistance Rct (second resistance component) obtained in step S160.
In step S250, the control means 21 determines whether or not the calculation of the temperature increase time for all the batteries B (n) has been completed. When the calculation of the temperature rising time of all the batteries B (n) is completed (Yes), the process proceeds to step S310. Otherwise (No), n + 1 is substituted for n via the step S260 (next battery B (n + 1) is prepared) and the process returns to step S230.

In step S310, the control means 21 selects the battery Bn to be first heated based on the result of step SA30, and proceeds to step S320.
In step S320, the control means 21 gradually increases the battery from the specific output voltage (n) over the temperature of the specific output voltage (n), the battery average voltage, and the temperature increase time (n) over the temperature increase time (n). The inherent DC voltage (n) reaching the average voltage is set, and the process proceeds to step S330.
In step S330, the control means 21 sets the temperature rising voltage (n) obtained by superimposing the temperature rising AC voltage on the inherent DC voltage (n) during the temperature rising time (n) corresponding to the battery B (n). , Applied to battery B (n), and proceeds to step S340.
In step S340, the control means 21 determines whether or not the temperature increase of all the batteries B (n) has been completed. If all the batteries B (n) have finished raising the temperature (Yes), the process is finished, and if not (No), the battery to be heated next through step S350 based on the result of step SA30. Select Bn and return to step S320.

Here, with reference to FIG. 8, an example of the intrinsic DC voltage in step S320 and the temperature rising voltage in step S330 will be described in detail.
FIG. 8 (A) shows an example of the temperature rising voltage when the specific output voltage V (j) of the battery B (j) is higher than the battery average voltage E. FIG. 8 (B) shows the battery B (k ) Shows an example of the temperature rising voltage when the specific output voltage V (k) is lower than the battery average voltage E.
In the case of the example shown in FIG. 8A, the control means 21 takes the time of the temperature rise time (j) of the battery B (j) from the specific output voltage V (j) of the battery B (j) to the battery average voltage. An intrinsic DC voltage reaching E (rectangle V (j) -OC (j) -D (j) in FIG. 8A) is set. Then, a temperature raising voltage obtained by superimposing the temperature raising AC voltage on this inherent DC voltage is applied to the battery B (j).
As described above, the AC voltage for temperature increase is, for example, an AC voltage having a frequency of 400 Hz and an amplitude of ± 50 mV. In this case, the output voltage of the battery B (j) is lowered by ΔV (j). Electric power corresponding to this ΔV (j) is stored in the power supply means 30.
In the case of the example shown in FIG. 8B, the control means 21 takes the time of the temperature rise time (k) of the battery B (k) and calculates the battery average from the specific output voltage V (k) of the battery B (k). The intrinsic DC voltage reaching the voltage E (rectangle V (k) -OC (k) -D (k) in FIG. 8B) is set. Then, a temperature raising voltage obtained by superimposing the temperature raising AC voltage on this inherent DC voltage is applied to the battery B (k). As described above, the AC voltage for temperature increase is, for example, an AC voltage having a frequency of 400 Hz and an amplitude of ± 50 mV. In this case, the output voltage of the battery B (k) is boosted by ΔV (k). Electric power corresponding to this ΔV (k) is supplied from the power supply means 30.
That is, after the excess power is accumulated in the power supply means 30 from the battery having the specific output voltage higher than the battery average voltage, the power stored in the power supply means 30 is supplied to the battery having the specific output voltage lower than the battery average voltage. The order of batteries to be heated determined in step SA30 is based on this concept.

For example, when the temperature of one lithium ion battery Bn of the battery pack BP mounted on the vehicle 1 is raised from −20 ° C. to 25 ° C., the temperature raising time (n) is about 20 seconds under the above conditions.
In the conventional vehicle 1 that does not use the battery control system (or battery control method) described in the present embodiment, the output power of the battery pack BP decreases to about 1/10 at a low temperature such as −20 ° C. In consideration, 48 battery Bn are connected in series to form a battery pack BP. However, by raising the temperature of the battery Bn, it is possible to recover the reduced power. From the viewpoint of ensuring startability at low temperatures, it is sufficient to recover at least five batteries. In this case, even if it takes about 20 seconds to raise the temperature of one battery Bn, it is possible to raise the temperature of all the batteries in a sufficiently short time. And there is a possibility that the number of batteries Bn constituting the battery pack BP can be greatly reduced.

As described above, the battery control system (or battery control method) described in the present embodiment can appropriately determine the internal resistance of the battery including the reaction resistance by determining the internal resistance of the battery using the AC impedance method. it can.
In addition, since the temperature of the portion having the reaction resistance in the battery Bn, that is, the entire inside of the battery Bn can be effectively increased, the energy efficiency is good.
Further, since the output voltage variation of each battery Bn constituting the battery pack BP can be flattened and the output voltage of each battery can be brought close to the battery average voltage, the charge / discharge characteristics of the battery pack BP can be utilized to the maximum. Will be able to.
In addition, since the current at the time of temperature rise is relatively small, it is not necessary to increase the thickness of the plurality of wirings so much, and an increase in weight, cost, and the like can be suppressed.
In addition, the process of step S110-S170 in the flowchart shown in FIG. 5 is performed by the timer process etc. at midnight when the vehicle 1 is not used, and the process after step SA10 is performed immediately before starting of the vehicle 1. It is also possible to do.

The battery control method and battery control system of the present invention are not limited to the appearance, configuration, processing, and the like described in this embodiment, and various modifications, additions, and deletions can be made without changing the gist of the present invention. .
In addition, the battery control method and the battery control system described in this embodiment are not limited to batteries mounted on hybrid vehicles and electric vehicles, and can be applied to batteries used in various devices.
In addition, the battery control method and the battery control system described in this embodiment are not limited to lithium ion batteries, and can be applied to temperature rising of various batteries.
Further, the above (≧), the following (≦), the greater (>), the less (<), etc. may or may not include an equal sign.
The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.

DESCRIPTION OF SYMBOLS 1 Vehicle 20 Control apparatus 21 Control means 22 Voltage output circuit 23 Current detection circuit 24 Voltage detection circuit 25 Temperature sensor 30 Power supply means Bn Battery BP Battery pack SL selection circuit

Claims (4)

In the battery control method of charging and discharging the target battery and raising the temperature of the battery by internal heat generation using the internal resistance of the battery,
The internal resistance can follow a first resistance component, which is a resistance component capable of following an alternating voltage of all frequencies, and an alternating voltage of a frequency equal to or lower than the first frequency, but to an alternating voltage of a frequency higher than the first frequency. A second resistance component, which is a resistance component that cannot be followed, and a resistance component that is capable of following an AC voltage of a second frequency lower than the first frequency but cannot follow an AC voltage having a frequency higher than the second frequency. A third resistance component, and
An AC voltage having a first predetermined amplitude set to an internal resistance measurement frequency that is equal to or lower than the first frequency and equal to or higher than the second frequency and two or more different frequencies with respect to the battery. Each internal resistance measurement AC voltage is applied, and each AC current that is a follow-up current generated for each applied internal resistance measurement AC voltage is measured, and each applied internal resistance measurement AC voltage is measured. And an internal resistance calculating step for calculating at least the first resistance component and the second resistance component in the battery based on each AC current measured corresponding to each of the internal resistance measuring AC voltages; ,
The battery ambient temperature, the target battery temperature, the calculated first resistance component and the second resistance component, and a temperature rise that is set to a frequency not higher than the first frequency and not lower than the second frequency. A temperature rising time calculating step for calculating a temperature rising time that is a time required for temperature rising of the battery based on an AC voltage for temperature rising that is an AC voltage having a frequency and a second predetermined amplitude;
A heating voltage obtained by superimposing the heating AC voltage on a DC voltage corresponding to the output voltage of the battery is applied to the battery during the heating time to charge and discharge the battery to raise the temperature. A temperature raising step,
Battery control method. The battery control method according to claim 1,
The battery is configured as a battery pack in which a plurality are connected in series,
Performing the internal resistance calculating step and the temperature rising time calculating step for each battery, calculating the first resistance component, the second resistance component, and the temperature rising time for each battery;
Before the heating step,
Dividing the output voltage of the battery pack by the number of batteries connected in series, calculating the battery average voltage,
In the heating step,
For each battery, the specific output voltage that is the output voltage of each battery is measured, and the direct current that gradually reaches the battery average voltage from the specific output voltage over the temperature increase time corresponding to each battery. A voltage is set, and the temperature rising voltage obtained by superimposing the temperature rising AC voltage on the set inherent DC voltage is applied to each battery during the temperature rising time corresponding to each battery to charge and discharge. To raise the temperature,
Battery control method. In a battery control system that charges and discharges a target battery and raises the temperature of the battery by internal heat generation using the internal resistance of the battery,
AC voltage generating means for generating an AC voltage having a predetermined frequency and a predetermined amplitude;
DC voltage generating means for generating a DC voltage of a predetermined voltage;
Power supply means to be a power source of the AC voltage and the DC voltage;
Voltage superimposing means capable of superimposing the AC voltage and the DC voltage;
AC current measuring means capable of measuring AC current;
DC voltage measuring means capable of measuring DC voltage;
Temperature measuring means capable of measuring the temperature of the target battery atmosphere;
Control means,
The internal resistance can follow a first resistance component, which is a resistance component capable of following an alternating voltage of all frequencies, and an alternating voltage of a frequency equal to or lower than the first frequency, but to an alternating voltage of a frequency higher than the first frequency. A second resistance component, which is a resistance component that cannot be followed, and a resistance component that is capable of following an AC voltage of a second frequency lower than the first frequency but cannot follow an AC voltage having a frequency higher than the second frequency. A third resistance component, and
The control means includes
Using the power supply means and the AC voltage generating means, the internal resistance measurement frequency is set to two or more types of frequencies that are the frequencies equal to or lower than the first frequency and the frequencies equal to or higher than the second frequency. Each of the internal resistance measuring AC voltages, which is an AC voltage having a first predetermined amplitude, is applied to the battery,
Using the alternating current measuring means, measure each alternating current that is each following current generated for each applied internal resistance measuring alternating voltage,
Based on each applied AC voltage for measuring internal resistance and each AC current measured corresponding to each of the internal resistance measuring voltages, at least the first resistance component and the second in the battery. Calculate the resistance component,
The battery ambient temperature measured using the temperature measuring means, a preset target battery temperature, the calculated first resistance component and the second resistance component, and a frequency equal to or lower than the first frequency, and Based on the temperature-raising AC voltage that is a frequency for raising the temperature set to a frequency equal to or higher than the second frequency and having a second predetermined amplitude, the rise is a time required for raising the temperature of the battery Calculate the warm time,
The output voltage of the battery measured by the DC voltage measuring means using the power supply means, the AC voltage generating means, the DC voltage generating means, the voltage superimposing means, and the DC voltage measuring means. The temperature rising voltage obtained by superimposing the temperature rising AC voltage on the DC voltage corresponding to is applied to the battery during the temperature rising time to charge and discharge the battery to raise the temperature.
Battery control system. The battery control system according to claim 3,
The battery is configured as a battery pack in which a plurality are connected in series,
The control means includes
Calculating the first resistance component, the second resistance component, and the temperature raising time for each battery;
Using the DC voltage measuring means, the output voltage of the battery pack is measured, and the average output voltage is calculated by dividing the measured output voltage by the number of batteries connected in series.
When applying the temperature raising voltage to each battery,
Using the DC voltage measuring means, the specific output voltage that is the output voltage of each battery is measured,
Using the power supply means, the AC voltage generating means, the DC voltage generating means, and the voltage superimposing means, for each battery, take the temperature rising time corresponding to each battery, The intrinsic DC voltage that gradually reaches the battery average voltage from the intrinsic output voltage is set, and the temperature raising voltage obtained by superimposing the temperature raising AC voltage on the set intrinsic DC voltage corresponds to each battery. During the temperature raising time, it is applied to each battery to charge / discharge to raise the temperature,
Battery control system.

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