JP6759892B2 - Power storage device characteristic measurement device, power storage device characteristic measurement method, and power storage device characteristic measurement program - Google Patents

Description

The present invention relates to a power storage device characteristic measurement device, a power storage device characteristic measurement method, and a power storage device characteristic measurement program.

Patent Document 1 describes a battery model identification method. In this method, the current waveform input to the battery is measured using a current sensor, and the voltage waveform of the terminal voltage of the battery is measured using the voltage sensor. Then, the system identification calculation unit identifies the parameters of the battery model based on these current waveforms and voltage waveforms. The current waveform is a square wave, and the amplitude of the current is a constant value.

Japanese Unexamined Patent Publication No. 2016-3963

Currently, various power storage devices such as lead storage batteries, lithium ion batteries, and lithium ion capacitors are used as vehicle power storage devices. Then, by combining these batteries, various types of hybrid systems have been put into practical use. For example, in recent years, the so-called μHEV method, in which a sub storage battery for energy regeneration during deceleration and driving of a starter motor after idling stop is provided separately from the main storage battery, has been particularly useful.

On the other hand, conventionally, in the fuel consumption simulation of a vehicle, various power sources such as an engine and a power storage device and a load are modeled, and a predetermined driving pattern is input to the model to calculate the fuel consumption. In such a model, it is extremely important to accurately model the complicated power storage device configuration in the hybrid system in order to accurately calculate the fuel consumption. When modeling a power storage device, a predetermined current waveform is input to the actual power storage device, the terminal voltage and input current are measured to obtain the current-voltage characteristics of the power storage device, and then the actual power storage device is obtained. The parameters of the power storage device model are identified by comparing the characteristics of the power storage device with the characteristics estimated by the power storage device model. Therefore, in order to obtain an accurate power storage device model, it is important to accurately measure the characteristics of the actual power storage device.

For example, in the conventional parameter identification method as described in Patent Document 1, a square wavy current having a certain peak value is repeatedly input to the power storage device, and a change in voltage between terminals of the power storage device is measured. However, with such a method, it is difficult to accurately measure the current-voltage characteristics of the power storage device. This is because the current-voltage characteristics of the power storage device are strictly non-linear, and the characteristics change depending on the magnitude of the input current.

The present invention has been made in view of such problems, and provides a power storage device characteristic measuring device, a power storage device characteristic measurement method, and a storage device characteristic measurement program capable of accurately measuring the characteristics of the power storage device. The purpose is to provide.

In order to solve the above-mentioned problems, the power storage device characteristic measuring device of the present invention is a device for measuring the characteristics of an in-vehicle power storage device, and is a current source that inputs a current to the power storage device and a current source that outputs a current. A control unit that controls the amount of current, a voltage sensor that measures the voltage between terminals of the power storage device, and a current sensor that measures the magnitude of the current input to the power storage device are provided, and the control unit discharges constant current. A current waveform including a state, a hibernation state after a constant current discharge state, a constant voltage charge state, and a hibernation state after a constant voltage charge state is output at least once within a predetermined measurement time from the current source. It is characterized by that.

Further, the method for measuring the characteristics of a power storage device of the present invention is a method for measuring the characteristics of a power storage device for a vehicle, and while inputting a current from a current source to the power storage device, the voltage between terminals of the power storage device and the power storage device Including the step of measuring the magnitude of the current input to, in the step, the constant current discharge state, the hibernation state after the constant current discharge, the constant voltage charge state, and the hibernation state after the constant voltage charge are simulated respectively. It is characterized in that a current waveform including a period at least once within a predetermined measurement time is output from a current source.

Further, the power storage device characteristic measurement program of the present invention is a program for operating a control unit that controls the amount of current output from a current source that inputs a current to the power storage device in a device that measures the characteristics of the power storage device for a vehicle. A current that includes at least one period within a predetermined measurement time for simulating a constant current discharge state, a hibernation state after a constant current discharge state, a constant voltage charging state, and a hibernation state after a constant voltage charging state. It is characterized in that the control unit is operated so that the waveform is output from the current source.

In the above-mentioned power storage device characteristic measurement device, power storage device characteristic measurement method, and power storage device characteristic measurement program, the current waveform output from the current source is a constant current discharge state, a hibernation state after a constant current discharge state, and a constant voltage charge. A period for simulating the state and the hibernation state after the constant voltage charging state is included at least once within a predetermined measurement time. That is, changes in the input current to the power storage device in the actual vehicle driving pattern, specifically, a constant current discharge state, a dormant state after the constant current discharge state, a constant voltage charging state, and a hibernation state after the constant voltage charging state. The current waveform including all of the above is input to the power storage device. This makes it possible to accurately measure the characteristics of the non-linear power storage device.

Further, the above-mentioned power storage device characteristic measuring device may be characterized in that the current waveform further includes a period of simulating a cranking state after a constant current discharge state at least once. As a result, the characteristics of the power storage device can be measured more accurately, including the change in the input current to the power storage device when restarting after the idling stop.

Further, the above-mentioned power storage device characteristic measuring device is characterized in that the control unit changes the amount of current in at least one of the period for simulating the constant current discharge state and the period for simulating the constant voltage charge state according to the charge rate. May be. Since the characteristics of the power storage device differ depending on the charge rate, the control unit performs such an operation, so that more accurate power storage device characteristics can be measured according to the charge rate.

Further, the above-mentioned power storage device characteristic measuring device is characterized in that the current waveform includes a period of simulating a constant current discharge state a plurality of times, and the amount of current in at least two of the plurality of periods is different from each other. May be good. As a result, it is possible to collect data on the characteristics of the power storage device for various current amounts and measure the characteristics of the power storage device with higher accuracy.

Further, in the above-mentioned power storage device characteristic measuring device, the current waveform includes a plurality of periods for simulating a hibernation state after constant voltage charging, and the lengths of at least two of the plurality of periods are different from each other. May be a feature. As a result, it is possible to collect data on the characteristics of the power storage device after various pauses and measure the characteristics of the power storage device more accurately.

According to the power storage device characteristic measurement device, the power storage device characteristic measurement method, and the power storage device characteristic measurement program according to the present invention, the characteristics of the power storage device can be measured with high accuracy.

It is a figure which shows the structure of the power storage device characteristic measuring apparatus by one Embodiment of this invention. It is a graph which shows an example of the current waveform output from a current source. (A) It is a graph which shows the part A of FIG. 2 enlarged. (B) It is a graph which shows enlarged part B of FIG. It is a flowchart which shows the power storage device characteristic measurement method by one Embodiment of this invention.

Hereinafter, embodiments of the power storage device characteristic measurement device, the power storage device characteristic measurement method, and the power storage device characteristic measurement program according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. In the following description, the input current to the power storage device refers to both the charge current input to the power storage device and the discharge current output from the power storage device, and when the sign of the input current is positive, charging is performed. When the sign of the input current is negative, it represents a discharge.

FIG. 1 is a diagram showing a configuration of a power storage device characteristic measuring device 1A according to an embodiment of the present invention. The power storage device characteristic measuring device 1A of the present embodiment is a device that measures the characteristics of the power storage device 10 for a vehicle. Here, the vehicle-mounted power storage device 10 refers to, for example, a lead storage battery, a lithium ion battery, a lithium ion capacitor, and the like. In particular, in a μHEV system vehicle, a lead storage battery is used as a main battery, and a lead storage battery, a lithium ion battery, a lithium ion capacitor, or the like is used as a sub battery. As shown in FIG. 1, the power storage device characteristic measuring device 1A includes a current source 20, a control unit 30 for controlling the current source 20, a voltage sensor 40, and a current sensor 50.

The current source 20 is an electric circuit that inputs a current to the power storage device 10. Usually, the current source of a vehicle is a three-phase alternator that generates electricity by using the rotation of an engine as a power source, and is called an alternator. Both ends of the alternator are connected to a full-wave rectifier circuit, and the output current from the alternator is converted into a direct current by the full-wave rectifier circuit. Here, a DC current source simulating an alternator and a full-wave rectifier circuit is used as the current source 20. The positive electrode 22 of the current source 20 is electrically connected to one terminal 11 of the power storage device 10, and the negative electrode 23 of the current source 20 is electrically connected to the other terminal 12 of the power storage device 10.

The control unit 30 is electrically connected to the control terminal 21 of the current source 20, and controls the amount of current output from the current source 20 by sending an electric signal to the control terminal 21. The control unit 30 is composed of, for example, a computer having a CPU and a memory, and operates according to a pre-recorded program. The detailed operation of the control unit 30 will be described later.

The voltage sensor 40 measures the voltage between terminals of the power storage device 10. One end 41 of the voltage sensor 40 is electrically connected to one terminal 11 of the power storage device 10, and the other end 42 of the voltage sensor 40 is electrically connected to the other terminal 12 of the power storage device 10. The voltage between terminals of the power storage device 10 measured by the voltage sensor 40 is recorded in the recording device 60 as time-series data indicating a part of the characteristics of the power storage device 10.

The current sensor 50 measures the magnitude of the current input to the power storage device 10. One end 51 of the current sensor 50 is electrically connected to the other terminal 12 (or one terminal 11) of the power storage device 10, and the other end 52 of the current sensor 50 is electrically connected to the negative electrode 23 (or positive electrode 22) of the current source 20. Is connected. The amount of current output from the current source 20 is controlled by the control unit 30, but the amount of current input to the power storage device 10 slightly fluctuates due to the electric resistance existing between the current source 20 and the power storage device 10. To do. The current sensor 50 accurately measures the amount of current input to the power storage device 10. The amount of input current to the power storage device 10 measured by the current sensor 50 is recorded in the recording device 60 as time-series data indicating a part of the characteristics of the power storage device 10. The amount of current measured by the current sensor 50 may be fed back to the control unit 30.

Here, the operation of the control unit 30 will be described in detail. FIG. 2 is a graph showing an example of a current waveform output from the current source 20 of the present embodiment. FIG. 3A is an enlarged graph showing part A in FIG. FIG. 3B is an enlarged graph showing part B of FIG. In these figures, the vertical axis represents the amount of current input to the power storage device 10, and the horizontal axis represents the elapsed time. The amount of current is represented as a positive value when charging the power storage device 10 and as a negative value when discharging. The control unit 30 outputs, for example, the current waveform shown in FIG. 2 from the current source 20.

As shown in FIGS. 3 (a) and 3 (b), this current waveform defines the first period D1, the second period D2, the third period D3, the fourth period D4, and the fifth period D5. Include at least once within the measurement time of. The predetermined measurement time is, for example, 1200 seconds. Basically, as shown in FIG. 3A, the first period D1, the second period D2, the third period D3, and the fourth period D4 continuously form one unit waveform. Further, as shown in FIG. 3B, the first period D1 and the fifth period D5 may continuously form one unit waveform. Then, in this current waveform, these unit waveforms are arranged in an arbitrary order in the time direction. The frequency of appearance of the former unit waveform is higher than the frequency of appearance of the latter unit waveform. The order of the periods D1 to D5 is not limited to those shown in these figures, and the periods D1 to D5 may be randomly arranged.

The first period D1 is a period for simulating a constant current discharge state. The first period D1 simulates a state in which the engine is stopped due to the idling stop, the alternator's power generation is insufficient, and the electric power for the electric equipment inside and outside the living room is discharged from the power storage device 10. The amount of discharge current at this time is constant with respect to time. The elements controlled by the control unit 30 in the first period D1 are the length of the period and the amount of current. The length of the first period D1 is preferably, for example, 10 seconds or more.

The current waveform shown in FIG. 2 includes the first period D1 a plurality of times. In this case, it is desirable that the current amounts of at least two periods out of the plurality of first period D1 are different from each other. For example, 10 (A) in the first first period D1, 20 (A) in the second first period D1, 30 (A) in the third first period D1, and 40 (A) in the fourth first period D1. As in A), the amount of current in the first period D1 may be gradually increased and returned to the first 10 (A) in the first period D1 of the nth time (n is an integer of 3 or more). By changing the discharge current in this way, the time constant can be determined for each of the plurality of first periods D1. In that case, it is preferable that the amount of current is the maximum rated current of the power storage device 10 or the alternator for at least one of the plurality of first periods D1. When the amount of current in the first period D1 changes for each of the plurality of first periods D1, the amount of current in the subsequent third period D3 also changes for each of the plurality of third periods D3.

The second period D2 is a period for simulating the cranking state after the constant current discharge state. That is, this second period D2 simulates a state in which the electric power for driving the starter motor is discharged from the power storage device 10 when the engine is restarted. The amount of discharge current at this time is also substantially constant with respect to time, but the time is extremely short as compared with the first period D1, and the absolute value of the amount of current is large. The elements controlled by the control unit 30 in the second period D2 are the length of the period and the amount of current.

The third period D3 is a period for simulating a constant voltage charging state. The third period D3 simulates a state in which the alternator generates electricity using the rotation of the engine as a power source and charges the power storage device 10 after the engine is restarted. At this time, the output current from the alternator rises sharply, and the voltage also rises accordingly, but the upper limit of the voltage is limited to a constant value for the protection of the power storage device 10 and other electrical equipment. Therefore, the third period D3 is a constant voltage charge, and the amount of current input to the power storage device 10 gradually decreases with the passage of time. The elements controlled by the control unit 30 in the third period D3 are the peak current amount and the time constant. The length of the third period D3 is determined so that the total charge amount in the third period D3 is equal to the total discharge amount in the first period D1 and the second period D2. However, if it is less than 10 seconds in such a case, it is desirable to set the length to 10 seconds.

The fourth period D4 is a period for simulating the hibernation state after the constant voltage charging state. In the fourth period D4, after the power storage device 10 is charged, all the electric power of the alternator is consumed by the electric equipment, and the power storage device 10 is not charged or discharged. In the fourth period D4, the amount of current is zero, and the only element controlled by the control unit 30 is the length of the period.

The current waveform shown in FIG. 2 includes the fourth period D4 a plurality of times. In this case, the lengths of at least two of the plurality of fourth periods D4 may be different from each other. For example, the length of the fourth period D4 may be gradually increased and returned to the initial length in the nth time (n is an integer of 3 or more) in the fourth period D4.

The fifth period D5 is a period for simulating the hibernation state after the constant current discharge state. In this fifth period D5, after the engine is stopped by idling stop and power for the electric equipment is supplied from the power storage device 10, all the electric equipment is stopped and the power storage device 10 is not charged or discharged. To do. In the fourth period D4, the amount of current is zero, and the only element controlled by the control unit 30 is the length of the period.

The current waveform may include the fifth period D5 multiple times. In this case, the lengths of at least two of the plurality of fifth periods D5 may be different from each other. For example, the length of the fifth period D5 may be gradually increased and returned to the initial length in the nth time (n is an integer of 3 or more) in the fifth period D5.

The control unit 30 may change the current amounts of the first period D1, the second period D2, and the third period D3 according to the charge rate (State Of Charge; SOC). For example, when the charging rate is large, it is desirable that the charging current value is smaller than when the charging rate is small. The discharge amount and charge amount in the first period D1, the second period D2, and the third period D3 are set so that the amount of change in the charge rate in one measurement is equal to or less than a predetermined threshold value (for example, 3%). To.

FIG. 4 is a flowchart showing a method for measuring the characteristics of the power storage device according to the present embodiment. The program that operates the control unit 30 operates the control unit 30 according to the flowchart shown in FIG.

First, as the first step S11, the current source 20, the voltage sensor 40, and the current sensor 50 are connected to the power storage device 10 to be measured, and recording of the output from the voltage sensor 40 and the current sensor 50 is started. Next, as the second step S12, the supply of the current whose waveform is controlled by the control unit 30 is started. The waveform of the current supplied here includes the waveform shown in FIG. 2, that is, the above-mentioned first period D1 to fifth period D5. After that, while inputting the current from the current source 20 to the power storage device 10, the voltage between the terminals of the power storage device 10 and the magnitude of the current input to the power storage device 10 are measured (third step S13).

The effects obtained by the power storage device characteristic measurement device 1A, the power storage device characteristic measurement method, and the power storage device characteristic measurement program of the present embodiment described above will be described. For example, in the conventional parameter identification method as described in Patent Document 1, a square wavy current having a constant peak value is repeatedly input to the power storage device, and a change in voltage between terminals of the power storage device is measured. However, with such a method, it is difficult to accurately measure the characteristics of the power storage device. There is no problem if the characteristics of the power storage device are linear, but in reality, the characteristics of the power storage device (particularly the polarization characteristics) are non-linear, and the characteristics change depending on the magnitude of the charging / discharging current. On the other hand, in the power storage device characteristic measurement device 1A, the power storage device characteristic measurement method, and the power storage device characteristic measurement program of the present embodiment, the current waveform output from the current source 20 simulates a constant current discharge state. A predetermined measurement time is a period D1, a third period D3 that simulates a constant voltage charging state, a fourth period D4 that simulates a hibernation state after constant voltage charging, and a fifth period D5 that simulates a hibernation state after constant current discharge. Include at least once in. That is, changes in the input current to the power storage device 10 in the actual vehicle running pattern, specifically, a constant current discharge state, a dormant state after constant current discharge, a constant voltage charging state, and a hibernation state after constant voltage charging. The current waveform including all of them is input to the power storage device 10. This makes it possible to cover various current input situations in the traveling pattern and accurately measure the characteristics of the non-linear power storage device 10. Further, since the hibernation state is included, the voltage return (return polarization) during the hibernation state can be reproduced, and the characteristics of the power storage device 10 can be measured more accurately.

Further, as in the present embodiment, the current waveform output from the current source 20 may include the second period D2 that simulates the cranking state after constant current discharge at least once. As a result, especially when measuring the characteristics of the lead-acid battery, the change in the input current to the power storage device 10 at the restart (cell start) after idling stop is further included in the current waveform, and the characteristics of the power storage device 10 are measured more accurately. it can.

Further, as described above, the control unit 30 sets the current amount of at least one of the first period D1 simulating the constant current discharge state and the third period D3 simulating the constant voltage charging state according to the charge rate (SOC). May be changed. Since the characteristics of the power storage device 10 differ depending on the charge rate, the control unit 30 can perform such an operation to measure more accurate power storage device characteristics according to the charge rate.

Further, as described above, the current waveform output from the current source 20 includes the first period D1 simulating the constant current discharge state a plurality of times, and is at least two times out of the plurality of first period D1s. The amounts of current may differ from each other. As a result, it is possible to collect data on the characteristics of the power storage device 10 with respect to various current amounts and measure the characteristics of the power storage device 10 with higher accuracy.

Further, as described above, the current waveform output from the current source 20 includes the fourth period D4 simulating the hibernation state after constant voltage charging a plurality of times, and at least two times out of the plurality of fourth period D4s. The lengths of the periods may differ from each other. As a result, it is possible to collect data on the characteristics of the power storage device 10 after various pauses and measure the characteristics of the power storage device 10 with higher accuracy.

The power storage device characteristic measurement device, the power storage device characteristic measurement method, and the power storage device characteristic measurement program according to the present invention are not limited to the above-described embodiments, and various other modifications are possible. For example, in the above embodiment, the current waveform includes a period for simulating a constant current discharge state, a cranking state, a hibernation state after a constant current discharge state, a constant voltage charging state, and a hibernation state after a constant voltage charging state. However, periods other than these may be further included. Further, in the above embodiment, the period for simulating the cranking state is included in the current waveform, but when measuring the characteristics of a power storage device other than the lead storage battery such as a lithium ion battery or a lithium ion capacitor, the cranking state is included. The period of simulation may be omitted.

1A ... Power storage device characteristic measuring device, 10 ... Power storage device, 11, 12 ... Terminal, 20 ... Current source, 21 ... Control terminal, 22 ... Positive electrode, 23 ... Negative electrode, 30 ... Control unit, 40 ... Voltage sensor, 50 ... Current Sensor, 60 ... Recording device, D1 ... 1st period, D2 ... 2nd period, D3 ... 3rd period, D4 ... 4th period, D5 ... 5th period.

Claims (7)

A device that measures the characteristics of in-vehicle power storage devices.
A current source that inputs a current to the power storage device and
A control unit that controls the amount of current output from the current source,
A voltage sensor that measures the voltage between the terminals of the power storage device and
A current sensor that measures the magnitude of the current input to the power storage device,
With
The control unit simulates each of the constant current discharge state, the hibernation state after the constant current discharge state, the constant voltage charging state, and the hibernation state after the constant voltage charging state at least once within a predetermined measurement time. A power storage device characteristic measuring device characterized in that a current waveform including each is output from a current source. The power storage device characteristic measuring device according to claim 1, wherein the current waveform further includes a period for simulating a cranking state after the constant current discharge state at least once. The first or second claim is characterized in that the control unit changes the amount of current in at least one of the period for simulating the constant current discharge state and the period for simulating the constant voltage charge state according to the charge rate. The power storage device characteristic measuring device described. Any of claims 1 to 3, wherein the current waveform includes a plurality of periods for simulating the constant current discharge state, and the amount of current in at least two of the plurality of periods is different from each other. The power storage device characteristic measuring device according to item 1. Claims 1 to 4, wherein the current waveform includes a plurality of periods for simulating a hibernation state after charging at a constant voltage, and the lengths of at least two of the plurality of periods are different from each other. The power storage device characteristic measuring device according to any one of the above items. It is a method of measuring the characteristics of an in-vehicle power storage device.
The step includes measuring the voltage between terminals of the power storage device and the magnitude of the current input to the power storage device while inputting the current from the current source to the power storage device.
In the step, the period for simulating the constant current discharge state, the hibernation state after the constant current discharge state, the constant voltage charge state, and the hibernation state after the constant voltage charge state is simulated at least once within a predetermined measurement time. A method for measuring characteristics of a power storage device, which comprises outputting a current waveform including the current from the current source. A program that operates a control unit that controls the amount of current output from a current source that inputs a current to the power storage device in a device that measures the characteristics of the power storage device for a vehicle.
A current waveform including a period for simulating a constant current discharge state, a hibernation state after the constant current discharge state, a constant voltage charge state, and a hibernation state after the constant voltage charge state at least once within a predetermined measurement time. A program for measuring the characteristics of a power storage device, which comprises operating the control unit so as to output from the current source.

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