JP2016205983A - Charge/discharge test apparatus and charge/discharge control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital control charge/discharge test apparatus capable of preventing fluctuation in an initial stage of a charge/discharge test of a secondary battery.SOLUTION: The charge/discharge test apparatus which performs a charge/discharge test on a secondary battery connected thereto, includes: a selection section unit selects a parameter for the charge/discharge test based on an impedance of the secondary battery; and a control unit that controls a converter using the parameter to execute the charge/discharge test of the secondary battery.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a charge / discharge test apparatus and a charge / discharge control method.

  In recent years, secondary batteries have been used in various fields ranging from large devices such as electric vehicles and solar cell systems at night and emergency storage batteries in disasters to small devices such as mobile phones. The manufacturer of the secondary battery maintains the quality of the secondary battery by performing a charge test and a discharge test using a charge / discharge test apparatus. On the other hand, the secondary battery test has been shifted from a conventional analog control method to a digital control method that is superior in cost, function, and the like (see, for example, Patent Document 1).

JP 2012-002640 A

  However, since the operation range of the digital control method is narrower than that of the analog control method, for example, when parameters suitable for the impedance of the secondary battery are not used, unexpected fluctuations (overshoot, undershoot, (Or oscillation, etc.) occurs, and the test result is affected.

  An object of the charge / discharge test apparatus and the charge / discharge control method disclosed herein is to provide a technique for suppressing fluctuation at the start of a test.

  According to one aspect, a charge / discharge test apparatus that performs a charge / discharge test by connecting a secondary battery, a selection unit that selects a parameter of the charge / discharge test based on the impedance of the secondary battery, and a converter is controlled by the parameter. And a control unit that performs a charge / discharge test of the secondary battery.

  According to one aspect, a charge / discharge control method in which a secondary battery is connected to perform a charge / discharge test selects a charge / discharge test parameter based on the impedance of the secondary battery, and controls the converter according to the parameter. A charge / discharge test of the secondary battery is performed.

  The charge / discharge test apparatus and the charge / discharge control method of the present disclosure can suppress variations at the start of the test by using a parameter suitable for the impedance of the secondary battery.

It is a figure which shows an example of the charging / discharging test apparatus which concerns on this embodiment. It is a figure which shows an example of the charging / discharging test apparatus of a comparative example. It is a figure which shows an example of a parameter table. It is a figure which shows an example of the voltage fluctuation at the time of parameter use below 1 m (ohm). It is a figure which shows an example of the voltage fluctuation at the time of parameter use below 50 mohm. It is a figure which shows the process example of a charging / discharging test. It is a figure which shows an example of the method of measuring the impedance of a secondary battery. It is a figure which shows the process example of the charging / discharging test in this embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 shows an example of a charge / discharge test apparatus 101 according to this embodiment. In FIG. 1, the charge / discharge test apparatus 101 includes a charge / discharge block 102 and a charge / discharge control block 103.

  The charge / discharge block 102 supplies charge / discharge voltage and charge / discharge current to the secondary battery 150 connected to the charge / discharge test apparatus 101. In FIG. 1, the charge / discharge block 102 includes a converter circuit 201 and a shunt resistor 202. The converter circuit 201 sets the charge / discharge voltage supplied to the secondary battery 150 according to the reference voltage controlled from the charge / discharge control block 103. The shunt resistor 202 is a resistor for measuring a charge / discharge current flowing between the converter circuit 201 and the secondary battery 150. The charge / discharge current flowing between the converter circuit 201 and the secondary battery 150 is measured by the charge / discharge control block 103 as a potential difference between both ends of the shunt resistor 202.

  The charge / discharge control block 103 controls the charge / discharge block 102 and performs a charge / discharge test of the secondary battery 150 in accordance with a command from a control personal computer (personal computer) 160 connected to the outside. For example, the charge / discharge control block 103 is configured to control the secondary battery 150 in a test mode such as a constant current (CC) test, a constant voltage (CV) test, or a constant power (CP) test. Conduct charge / discharge test.

  In FIG. 1, the charge / discharge control block 103 includes a control unit 301, a reference voltage D / A converter 302, a current measurement A / D converter 303, a voltage measurement A / D converter 304, an IF ( interface) 305 and memory 306.

  The control unit 301 uses a device capable of high-speed processing such as a DSP (Digital Signal Processor), and controls the overall operation of the charge / discharge test apparatus 101. In the present embodiment, the control unit 301 includes a charge / discharge control unit 351, an impedance acquisition unit 352, and a parameter selection unit 353. The charge / discharge control unit 351 sets the charge / discharge voltage and charge / discharge current of the charge / discharge block 102 according to the test mode instructed from the control personal computer 160. Further, the charge / discharge control unit 351 measures the charge / discharge voltage and the charge / discharge current and outputs them to the control personal computer 160. The impedance acquisition unit 352 performs a process of acquiring the value of the impedance Rz of the secondary battery 150 connected to the charge / discharge test apparatus 101. The impedance acquisition unit 352 acquires the value of the impedance Rz input by the operator from the control personal computer 160, for example. Alternatively, the impedance acquisition unit 352 measures the impedance Rz of the secondary battery 150 connected to the charge / discharge test apparatus 101 and acquires the value of the impedance Rz. A method for measuring the impedance Rz will be described later. The parameter selection unit 353 performs processing for selecting a parameter for controlling the converter circuit 201 in accordance with the value of the impedance Rz of the secondary battery 150 acquired by the impedance acquisition unit 352.

  The D / A converter 302 converts the digital signal output from the control unit 301 into an analog signal in order to control the converter circuit 201. Here, the control unit 301 outputs a reference voltage for controlling the charge / discharge voltage of the converter circuit 201 as a digital signal. Converter circuit 201 controls the charge / discharge voltage applied to secondary battery 150 in accordance with the reference voltage output from D / A converter 302. For example, when the reference voltage is positive, the converter circuit 201 controls the charging voltage according to the magnitude of the reference voltage, and when the reference voltage is negative, the converter circuit 201 controls the discharge voltage according to the magnitude of the reference voltage. Here, the control of the charge / discharge voltage at the time of the CV test has been described, but the control of the charge / discharge current at the time of the CC test or the CP test can be performed in the same manner.

  The A / D converter 303 converts an analog voltage generated across the shunt resistor 202 into a digital voltage. The voltage generated at both ends of the shunt resistor 202 changes according to the magnitude of the charge / discharge current flowing through the shunt resistor 202. The control unit 301 measures the charge / discharge current flowing through the secondary battery 150 by reading the voltage generated across the shunt resistor 202 via the A / D converter 303.

  The A / D converter 304 converts the analog voltage at both ends of the secondary battery 150 into a digital voltage. The control unit 301 measures the voltage between the terminals of the secondary battery 150 during the charge / discharge test by reading the voltage across the secondary battery 150 via the A / D converter 304.

  The IF 305 has an interface circuit for connecting the control personal computer 160. The control personal computer 160 transmits and receives control data and measurement data to and from the control unit 301 via the IF 305. As the control data, for example, the control personal computer 160 transmits charge / discharge test information (test mode, test time, etc.) to the charge / discharge test apparatus 101. Alternatively, as the control data, the charge / discharge test apparatus 101 transmits response information (such as test start and test end) and alarm information (such as operation failure and temperature abnormality) to the control personal computer 160. Further, the charge / discharge test apparatus 101 transmits measurement data (charge / discharge voltage, charge / discharge current, etc.) of the charge / discharge test of the secondary battery 150 to the control personal computer 160.

  As the memory 306, a semiconductor memory or the like is used, and information on parameters necessary for the operation of the charge / discharge test apparatus 101 is stored in the memory 306. In the present embodiment, parameter information corresponding to the impedance of the secondary battery 150 is stored in the memory 306 in advance.

  FIG. 2 shows an example of the charge / discharge test apparatus 901 of the comparative example. In FIG. 2, the charge / discharge test apparatus 901 includes a charge / discharge block 102 and a charge / discharge control block 903. 2, blocks having the same reference numerals as those in FIG. 1 have the same or similar functions as those in FIG.

  As described with reference to FIG. 1, the charge / discharge block 102 supplies a charge / discharge voltage and a charge / discharge current to the secondary battery 150 connected to the charge / discharge test apparatus 901. The converter circuit 201 sets the charge / discharge voltage supplied to the secondary battery 150 according to the reference voltage controlled from the charge / discharge control block 903. The charge / discharge current flowing between the converter circuit 201 and the secondary battery 150 is measured by the charge / discharge control block 903 as a potential difference between both ends of the shunt resistor 202.

  Similarly to the charge / discharge control block 103, the charge / discharge control block 903 controls the charge / discharge block 102 and performs a charge / discharge test of the secondary battery 150 in accordance with a command from the control personal computer 160 connected to the outside. 2, the charge / discharge control block 903 includes a control unit 801, a reference voltage D / A converter 302, a current measurement A / D converter 303, a voltage measurement A / D converter 304, an IF 305, An analog correction circuit 802 and a diode 803 are included.

  The control unit 801 uses a built-in CPU (Central Processing Unit) or the like, and sets the charge / discharge voltage and charge / discharge current of the charge / discharge block 102 according to the test mode instructed from the control personal computer 160. In addition, the control unit 801 measures the charge / discharge voltage and charge / discharge current of the secondary battery 150 and outputs them to the control personal computer 160.

  Here, the D / A converter 302, the A / D converter 303, the A / D converter 304, and the IF 305 are the D / A converter 302, A / D converter 303, and A / D converter described in FIG. Since the operation is similar to that of the device 304 and the IF 305, a duplicate description is omitted.

  The analog correction circuit 802 has an analog circuit for monitoring the voltage between the terminals of the secondary battery 150 and controlling the control voltage output from the D / A converter 302 to the converter circuit 201.

  The diode 803 functions as a switch that lowers the control reference voltage output from the D / A converter 302 in accordance with the output voltage of the analog correction circuit 802.

  In this way, the charge / discharge test apparatus 901 of the comparative example monitors the inter-terminal voltage of the secondary battery 150 in real time by the analog correction circuit 802, and lowers the control voltage so that the inter-terminal voltage does not become too large. Can do.

  Next, a method for controlling the charge / discharge voltage when the CV test is performed will be described. When the CV test is performed by digital control, the charge / discharge control unit 351 outputs the reference voltage to the D / A converter 302 so that the charge / discharge voltage becomes a set voltage according to a differential equation based on PI (Proportional Integral) control. Control the control voltage. Since digital control is difficult to perform continuously like analog control, the control is discretely performed at a predetermined sampling interval.

Here, the control amount of the control voltage is U, the error between the set voltage and the measurement voltage is E, the coefficient B0, and the coefficient B1. Also, the current sampling process is the nth (n is a positive integer) process, the previous sampling process is the (n-1) th time, and the second sampling process is the (n-2) th time. When the inter-terminal voltage of the n-th secondary battery 150 is Vd (n) and the set voltage of the charge / discharge test is Vs, an error E (n) with respect to the set voltage is expressed by (Equation 1).
E (n) = Vs-Vd (n) (Formula 1)
Further, if the control amount updated in the n-th sampling is U (n), the control amount U (n) is expressed by (Expression 2).
U (n) = B0 · E (n) + B1 · E (n-1) + U (n-1) (Formula 2)
In (Expression 2), the coefficients B0 and B1 are expressed as (Expression 3) and (Expression 4) using a sampling constant Fs indicating a sampling period used in digital control, a proportional coefficient P, and an integral coefficient I. Is done.
B0 = P + Fs / (2 · I) (Formula 3)
B1 = -P + Fs / (2 · I) (Formula 4)
In the present embodiment, a case where the sampling period for updating the control amount is 10 μsec (Fs = 0.00001) will be described.

  FIG. 3 shows an example of the parameter table 306 a stored in the memory 306. In FIG. 3, the parameter table 306a shows an example of the proportional coefficient P and the integral coefficient I when the impedance Rz of the secondary battery 150 is 1 mΩ or less, 10 mΩ or less, and 50 mΩ or less. In addition, 10 mΩ or less includes 1 mΩ or less, and 50 mΩ or less includes 10 mΩ or less and 1 mΩ or less.

  Here, in FIG. 3, it is known that the voltage is stable when the proportional coefficient P is inversely proportional to the impedance Rz and the integral coefficient I is proportional to the impedance Rz. For example, the proportional coefficient P and the integral coefficient I when the impedance Rz is 10 mΩ or 50 mΩ can be obtained on the basis of the proportional coefficient P when the impedance Rz is 1 mΩ and the integral coefficient I is 0.0001. When the impedance Rz is 10 mΩ, since the impedance Rz is 10 times as large as 1 mΩ, the proportionality coefficient P is 1/10 that of 1 mΩ, and the integration coefficient I is 10 times that of 1 mΩ. 0.001. Similarly, when the impedance Rz is 50 mΩ, 50 mΩ is 50 times as large as the impedance Rz of 1 mΩ, so the proportionality coefficient P is 2/50 compared to 1 mΩ, and the integral coefficient I is 1 mΩ. 50 times, 0.005.

  The proportional coefficient P and the integral coefficient I shown in the parameter table 306a are used when obtaining the coefficient B0 and the coefficient B1 described in (Expression 3) and (Expression 4). That is, the control amount of the voltage applied to the secondary battery 150 differs according to the impedance Rz of the secondary battery 150. For example, in FIG. 3, when the impedance Rz of the secondary battery 150 is 1 mΩ or less, the proportionality coefficient P is 100, and the integration coefficient I is 0.0001. Here, the control amount increases as the proportional coefficient P increases, and conversely, the control amount decreases as the proportional coefficient P decreases. Further, the control amount decreases as the integration coefficient I increases, and the control amount increases as the integration coefficient I decreases. Here, it is known from the experiment result of the inventor that it is desirable to control so that the product of the proportional coefficient P and the integral coefficient I is constant. In the case of the parameter table 306a shown in FIG. 3, the proportional coefficient P and the integral coefficient I are set so that the product of the proportional coefficient P and the integral coefficient I becomes 0.01.

  Here, when an appropriate parameter suitable for the impedance Rz of the secondary battery 150 is not set, the voltage applied from the charge / discharge test apparatus 101 to the secondary battery 150 at the start of the CV test varies, or in the worst case, oscillation occurs. There is a risk of doing.

  FIG. 4 shows an example of voltage fluctuation when using a parameter of 1 mΩ or less. In FIG. 4, the horizontal axis represents time t, and the vertical axis represents the voltage V between terminals of the secondary battery 150.

  FIG. 4A shows an example of fluctuations in the voltage between the terminals of the secondary battery 150 when the CV test is started when the impedance Rz of the secondary battery 150 is 1 mΩ or less. FIG. 4B shows a variation example of the inter-terminal voltage of the secondary battery 150 when the CV test is started when the impedance Rz of the secondary battery 150 is 10 mΩ or less. Further, FIG. 4C shows an example of fluctuation in the voltage between the terminals of the secondary battery 150 when the CV test is started when the impedance Rz of the secondary battery 150 is 50 mΩ or less.

  Here, in the three cases of FIGS. 4A to 4C, the parameters to be used are the same value. In the example of FIG. 4, the proportionality coefficient P of 1 mΩ or less shown in the parameter table 306a of FIG. And the integral coefficient I is used. Accordingly, FIG. 4A uses parameters that match the impedance Rz (1 mΩ or less) of the secondary battery 150, but FIGS. 4B and 4C show the impedance Rz of the secondary battery 150. Matched parameters are not used.

  In FIG. 4A, the voltage fluctuation at the start of the CV test is smaller and the fluctuation time is shorter than those in FIG. 4B and FIG. On the other hand, in the example of FIG. 4B, the impedance Rz of the secondary battery 150 is 10 mΩ or less for a parameter of 1 mΩ or less, and an appropriate parameter is not used. In comparison, the voltage fluctuation at the start of the CV test is large and the fluctuation time is long. Furthermore, in the example of FIG. 4C, the impedance Rz of the secondary battery 150 is 50 mΩ or less for a parameter of 1 mΩ or less, and an appropriate parameter is not used. The voltage fluctuation at the start of the test is large, and it is in an oscillation state. In FIG. 4C, the charge / discharge test apparatus 101 detects that the secondary battery 150 is in the oscillation state when the voltage across the terminals of the secondary battery 150 exceeds the range of the determination value ± Vx for a predetermined time. The alarm is notified to the control personal computer 160. The operator is required to stop the charge / discharge test and perform the retest.

  Here, in the case of the CV test, it is required to keep the voltage between the terminals of the secondary battery 150 constant. Since the charge / discharge test apparatus 901 of the comparative example described in FIG. 2 uses an analog circuit, the reference voltage can be controlled in real time so that fluctuations in the voltage between the terminals of the secondary battery 150 are suppressed. On the other hand, in the digital control, since the reference voltage is controlled discretely, there is a problem that it is difficult to cope with a rapid voltage fluctuation. For this reason, like the charge / discharge test apparatus 101 of this embodiment, when performing a charge / discharge test by digital control, it is required to use an appropriate parameter that matches the impedance Rz of the secondary battery 150.

  FIG. 5 shows an example of voltage fluctuation when using a parameter of 50 mΩ or less. In FIG. 5, the horizontal axis represents time t, and the vertical axis represents the voltage V between terminals of the secondary battery 150.

  FIG. 5A shows a variation example of the voltage between the terminals of the secondary battery 150 when the CV test is started when the impedance Rz of the secondary battery 150 is 1 mΩ or less. FIG. 5B shows a variation example of the inter-terminal voltage of the secondary battery 150 when the CV test is started when the impedance Rz of the secondary battery 150 is 10 mΩ or less. Further, FIG. 5C shows an example of fluctuation in the voltage between the terminals of the secondary battery 150 when the CV test is started when the impedance Rz of the secondary battery 150 is 50 mΩ or less.

  Here, in the three cases of FIGS. 5A to 5C, the parameters used are the same values, and the proportional coefficient P and the integral coefficient I of 50 mΩ or less shown in the parameter table 306a of FIG. 3 are used. It is done.

  In the example of FIG. 5C, parameters that match the impedance Rz (50 mΩ or less) of the secondary battery 150 are used. Therefore, compared to FIGS. 5A and 5B, the CV test is started. Voltage fluctuation is small and fluctuation time is short. On the other hand, in the example of FIG. 5A, the impedance Rz of the secondary battery 150 is 1 mΩ or less for a parameter of 50 mΩ or less, and an appropriate parameter is not used. Fluctuation time after test start is long and convergence is slow. Furthermore, in the example of FIG. 5B, the impedance Rz of the secondary battery 150 is 10 mΩ or less for a parameter of 50 mΩ or less, and an appropriate parameter is not used. In the example of FIG. 5B, the variation time after the start of the CV test is shorter than that of FIG. 5A, but longer than that of FIG. 5C, and the convergence is slower than that of FIG.

As described above, in the example of FIG. 5, by using a parameter of 50 mΩ or less, problems such as severe voltage fluctuation and oscillation as shown in FIGS. 4B and 4C can be solved. However, as shown in FIGS. 5A and 5B, there is a problem that convergence is slow and small fluctuations continue for a long time. On the other hand, the charge / discharge test apparatus 901 of the comparative example described in FIG. 2 controls the control voltage so that the voltage between the terminals of the secondary battery 150 is monitored in real time by an analog circuit so that the voltage between the terminals does not become too large. For this reason, even when the convergence is controlled so as to be accelerated, no severe voltage fluctuation or oscillation occurs as shown in FIGS. 4B and 4C. On the other hand, when performing digital control like the charge / discharge test apparatus 101 according to the present embodiment, it is required to use an appropriate parameter that matches the impedance Rz of the secondary battery 150.
[Example]
FIG. 6 shows a processing example of the charge / discharge test. The charge / discharge test described with reference to FIG. 6 starts after the operator selects the impedance Rz of the secondary battery 150.

  In step S <b> 101, control personal computer 160 receives an input from an operator who specifies impedance Rz of secondary battery 150. For example, the operator reads the parameter table 306 a stored in the memory 306 of the charge / discharge test apparatus 101 from the control personal computer 160 and displays it on the monitor screen of the control personal computer 160. Then, the operator selects a parameter corresponding to the impedance Rz of the secondary battery 150 connected to the charge / discharge test apparatus 101. Thereby, an input for designating the impedance Rz of the secondary battery 150 is made to the control personal computer 160. The impedance Rz of the secondary battery 150 may be measured when the secondary battery 150 is connected to the charge / discharge test apparatus 101, or information on the secondary battery 150 is input to the control personal computer 160 in advance. You may make it refer to the information of the input secondary battery 150. FIG.

  In step S <b> 102, the control personal computer 160 waits until the operator transmits a command to start the charge / discharge test to the control unit 301 of the charge / discharge test apparatus 101. For example, when the operator presses the test start button displayed on the monitor screen of the control personal computer 160 by operating the mouse or the like, the process proceeds to step S103.

  In step S103, upon receiving a test start command from the control personal computer 160, the control unit 301 selects a parameter according to the impedance Rz of the secondary battery 150 specified by the operator in step S101 with reference to the parameter table 306a. .

  In step S104, the control unit 301 executes the CV test by applying the parameters selected in step S103 to (Expression 2) to (Expression 4).

In this way, the charge / discharge test apparatus 101 according to the present embodiment uses parameters suitable for the impedance Rz of the connected secondary battery 150, which causes the problem described with reference to FIGS. 4 and 5. CV test can be performed.
[Other embodiments]
In the embodiment shown in FIG. 6, the operator selects the impedance Rz of the secondary battery 150, but in this embodiment, the charge / discharge test apparatus 101 measures the impedance Rz of the secondary battery 150, Automatically select parameters.

  FIG. 7 shows an example of a method for measuring the impedance Rz of the secondary battery 150 before the start of the test. In FIG. 7, the horizontal axis indicates time t, and the vertical axis indicates current i. Here, the control of FIG. 7 is executed by the charge / discharge control block 103 shown in FIG. In FIG. 7, the control unit 301 of the charge / discharge control block 103 executes a sequence for obtaining the impedance Rz of the secondary battery 150 before the test start timing T6. In FIG. 7, the control unit 301 measures the impedance Rz of the secondary battery 150 by causing the secondary battery 150 to pass a preliminary current Ip that is smaller than the current passed to the secondary battery 150 in the charge / discharge test. Here, as the preliminary current Ip, in order to reduce the influence on the test of the secondary battery 150, it is preferable to use a current that is smaller than the initial current Is. For example, when the initial current Is is 80 A, the reserve current Ip is set to about ± 1 A to ± 10 A. In FIG. 7, the control unit 301 changes the standby current Ip (± 5 A) that flows through the secondary battery 150 at intervals of 10 msec, for example, and measures the current ΔIp and the voltage ΔVp at the moment when the standby current Ip starts to flow. In the example of FIG. 7, the control unit 301 changes the preliminary current Ip at intervals of 10 msec, but may measure at intervals other than 10 msec. Further, the control unit 301 may change the preliminary current Ip only to the + side or only the − side.

  Here, as described in FIG. 1, the current flowing through the secondary battery 150 can be measured as the voltage value across the shunt resistor 202. The control unit 301 converts the voltage value at both ends of the shunt resistor 202 into a digital value by the A / D converter 303 for current measurement, and measures the current ΔIp. Further, the voltage ΔVp can be measured by converting the voltage value between the terminals of the secondary battery 150 into a digital value by the A / D converter 304 for voltage measurement, as described with reference to FIG.

In FIG. 7, the current i in the 10 msec period from the timing T1 to the timing T2 is 0 (A). Then, the control unit 301 measures the current ΔIp1 and the voltage ΔVp1 at the moment when the current changes from 0A to + 5A at the timing T2. And the control part 301 calculates | requires the impedance R1 in the timing T2 by (Formula 5).
R1 = ΔVp1 / ΔIp1 (Formula 5)
Similarly, the control unit 301 measures the current ΔIp2 and the voltage ΔVp2 at the moment when the current I changes from 0A to −5A at the timing T4. Then, the impedance R2 at the timing T4 is obtained by (Equation 6).
R2 = ΔVp2 / ΔIp2 (Formula 6)
Thereafter, the control unit 301 obtains an average value of two times of the impedance R1 obtained at the timing T2 and the impedance R2 obtained at the timing T4, and obtains the impedance Rz of the secondary battery 150 by (Equation 7).
Rz = (R1 + R2) / 2 (Formula 7)
In this way, the control unit 301 of the charge / discharge control block 103 can measure the impedance Rz of the secondary battery 150 connected to the charge / discharge test apparatus 101. Here, since the impedance Rz of the secondary battery 150 actually has an imaginary part, it is difficult to obtain an accurate impedance Rz by the method shown in FIG. 7, but the value of the impedance Rz can be easily known. . Thereby, the charge / discharge test apparatus 101 according to the present embodiment can perform the charge / discharge test with the parameters suitable for the secondary battery 150 with reference to the parameter table 306a described with reference to FIG.

  FIG. 8 shows a processing example of the charge / discharge test in the present embodiment. In the charge / discharge test described in FIG. 8, the charge / discharge test apparatus 101 automatically acquires the impedance Rz of the secondary battery 150 as described in FIG. 7 and starts the charge / discharge test.

  In step S <b> 201, the control personal computer 160 waits until the operator transmits a command to start the charge / discharge test to the control unit 301 of the charge / discharge test apparatus 101. For example, when the operator presses the test start button displayed on the monitor screen of the control personal computer 160 by operating the mouse or the like, the process proceeds to step S202.

  In step S202, the control unit 301 measures the impedance Rz of the secondary battery 150 by the method described in FIG.

  In step S203, the control unit 301 selects a parameter according to the impedance Rz of the secondary battery 150 measured in step S202 with reference to the parameter table 306a.

  In step S204, the control unit 301 executes the CV test by applying the parameters selected in step S203 to (Expression 2) to (Expression 4).

  In this way, the charge / discharge test apparatus 101 according to the present embodiment uses parameters suitable for the impedance Rz of the connected secondary battery 150, which causes the problem described with reference to FIGS. 4 and 5. CV test can be performed.

  Here, a method of selecting a parameter with reference to the parameter table 306a based on the measured impedance Rz of the secondary battery 150 in step S203 will be described. For example, when the measured impedance Rz is 0.5 mΩ, the proportional coefficient P is set to 100 and the integral coefficient I is set to 0.0001. Alternatively, when the measured impedance Rz is 8 mΩ, the proportional coefficient P is set to 10 and the integral coefficient I is set to 0.001. Similarly, when the measured impedance Rz is 45 mΩ, the proportional coefficient P is set to 2 and the integral coefficient I is set to 0.005.

  However, when the measured impedance Rz is 2 mΩ, for example, a parameter of 1 mΩ or less (proportional coefficient P is 100, integration coefficient I is set to a parameter of 10 mΩ or less (proportional coefficient P is 10, integral coefficient I is 0.001). May be set to 0.0001). Therefore, the coefficient may be optimized so that the product of the proportional coefficient P and the integral coefficient I becomes a constant value 0.01. For example, when the measured impedance Rz of the secondary battery 150 is 2 mΩ, a value obtained by halving a proportionality factor P (100) of 1 mΩ or less is a proportionality factor P (50) in the case of 2 mΩ. Similarly, the integral coefficient I when the impedance Rz is 2 mΩ is a value (0.0002) obtained by doubling the integral coefficient I (0.0001) of 1 mΩ or less.

  In this way, a parameter corresponding to the impedance Rz of the secondary battery 150 may be obtained.

  As described above, the charge / discharge test apparatus 101 according to the present embodiment reduces the voltage fluctuation at the start of the test by selecting a parameter according to the impedance Rz of the secondary battery 150 performing the charge / discharge test. be able to.

  From the above detailed description, features and advantages of the embodiments will become apparent. This is intended to cover the features and advantages of the embodiments described above without departing from the spirit and scope of the claims. Also, any improvement and modification should be readily conceivable by those having ordinary knowledge in the art. Therefore, there is no intention to limit the scope of the inventive embodiments to those described above, and appropriate modifications and equivalents included in the scope disclosed in the embodiments can be used.

DESCRIPTION OF SYMBOLS 101,901 ... Charge / discharge test apparatus; 102 ... Charge / discharge block; 103 ... Charge / discharge control block; 150 ... Secondary battery; 160 ... Control personal computer; 202 ... Shunt resistor; 301, 801 ... Control unit; 302 ... D / A converter; 303 ... A / D converter; 304 ... A / D converter; IF; 306a, parameter table; 306, memory; 351, charge / discharge control unit; 352, impedance acquisition unit; 353, parameter selection unit; 802, analog correction circuit; ..Diodes; Rz ... impedance

Claims (12)

In a charge / discharge test apparatus for performing a charge / discharge test by connecting a secondary battery,
A selection unit for selecting a parameter of a charge / discharge test based on the impedance of the secondary battery;
A charge / discharge test apparatus comprising: a control unit that controls the converter according to the parameter and performs a charge / discharge test of the secondary battery. The charge / discharge test apparatus according to claim 1,
A measurement unit for measuring the impedance of the secondary battery;
The said selection part measures the impedance of the said secondary battery by the said measurement part before a test start, and selects the parameter of a charging / discharging test based on the said impedance. The charging / discharging test apparatus characterized by the above-mentioned. The charge / discharge test apparatus according to claim 1 or 2,
The charge / discharge test apparatus is a constant voltage charge / discharge test. In the charge / discharge test apparatus according to any one of claims 1 to 3,
The said control part discretely performs the process which measures charging / discharging electric current and charging / discharging voltage, and controls the said converter at a predetermined sampling interval, The charging / discharging test apparatus characterized by the above-mentioned. The charge / discharge test apparatus according to claim 4,
The parameter is a combination of a proportional constant P and an integral constant I corresponding to the impedance of the secondary battery, and the control amount U (n) at the time of sampling of the converter (n: positive integer) is The set voltage Vs of the charge / discharge test, the inter-terminal voltage Vd of the secondary battery, and the sampling constant Fs are obtained by the following equation.
B0 = P + Fs / (2 ・ I)
B1 = -P + Fs / (2 ・ I)
E (n) = Vs-Vd (n)
U (n) = B0 ・ E (n) + B1 ・ E (n-1) + U (n-1)
The charge / discharge test apparatus characterized by the above-mentioned. In the charge / discharge test apparatus according to claim 5,
The charge / discharge test apparatus according to claim 1, wherein the parameter is set so that a product of the proportionality constant P and the integral constant I becomes a predetermined constant value regardless of the impedance of the secondary battery. In the charge / discharge control method of connecting a secondary battery and performing a charge / discharge test,
A charge / discharge control method comprising: selecting a charge / discharge test parameter based on the impedance of the secondary battery, and controlling the converter according to the parameter to perform the charge / discharge test of the secondary battery. The charge / discharge control method according to claim 7,
Before starting the test, the impedance of the secondary battery is measured, and a charge / discharge test parameter is selected based on the impedance. The charge / discharge control method according to claim 7 or 8,
The charge / discharge test method is a constant voltage charge / discharge test. The charge / discharge control method according to any one of claims 7 to 9,
A charge / discharge control method characterized by discretely executing a process of measuring a charge / discharge current and a charge / discharge voltage and controlling the converter at a predetermined sampling interval. The charge / discharge control method according to claim 10,
The parameter is a combination of a proportional constant P and an integral constant I corresponding to the impedance of the secondary battery, and the control amount U (n) at the time of sampling of the converter (n: positive integer) is The set voltage Vs of the charge / discharge test, the inter-terminal voltage Vd of the secondary battery, and the sampling constant Fs are obtained by the following equation.
B0 = P + Fs / (2 ・ I)
B1 = -P + Fs / (2 ・ I)
E (n) = Vs-Vd (n)
U (n) = B0 ・ E (n) + B1 ・ E (n-1) + U (n-1)
The charge / discharge control method characterized by the above-mentioned. The charge / discharge control method according to claim 11,
The charge / discharge control method, wherein the parameter is set so that a product of the proportionality constant P and the integral constant I becomes a predetermined constant value regardless of the impedance of the secondary battery.

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