JPH1123676A - Method and device for measuring charge characteristics of secondary cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make appropriate conformity judgment by calculating an average value from the measurement data of a specific number of samples obtained from a voltage or a current detection means and calculating the upper-limit and lower-limit values of reference data from the measurement data and the estimation value of calculated standard deviation. SOLUTION: With secondary cells 1a and 1b being retained at a retention mechanism 2 of a charge characteristic measuring device 16 of a secondary cell, data are read by a current detector 7a and a voltage detector 8b and are sent to a microprocessor 11 via a multiplexer 9 and an A/D converter 10. The data of charge characteristics that become a reference are stored at a memory 11b of the microprocessor 11 in advance, and the reference data are compared with measurement data. When a charge period is reached, the sample values of charge voltage and current are averaged and the amount of estimation of standard deviation is calculated. The lower-limit and upper-limit reliability section as conformity criterion are obtained from a correspondence table corresponding to the number of samples and a specific operation expression.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for measuring charging characteristics of mass-produced secondary batteries.

[0002]

2. Description of the Related Art Conventionally, in order to obtain average charging characteristics of mass-produced secondary batteries, a plurality of sheets on which the charging characteristics of individual secondary batteries are printed out are accumulated, and the characteristic curves on the sheets are averaged. Was. As shown in FIG. 7, the charging characteristic of the secondary battery is a change curve between the terminal voltage Vt of the secondary battery and the charging current it from the start to the end of the charging. The capacity of the battery.

[0003] However, this method involves manual calculations and is therefore unreliable. Since it takes a lot of man-hours for calculation, it is not possible to cover all channels in an actual production line. Another problem is that information cannot be directly handled by a computer. In addition, in the charging test, when monitoring for extracting a defective product, parameters for monitoring (upper limit and lower limit of pass / fail) were set in the charging device.
However, in that case, there is a disadvantage that the method of setting the parameters is complicated, and it takes time to determine an appropriate parameter.

[0004]

The problem to be solved by the present invention is to sequentially measure the charging characteristics of a large number of mass-produced secondary batteries and to extract those having abnormal characteristics at the time of measurement. For a battery with no abnormality, a measurement result is calculated as reference data, and an upper limit value and a lower limit value can be calculated from an estimated amount of a standard deviation in the calculation. It is an object of the present invention to provide a method and an apparatus for measuring a charging characteristic of a secondary battery, in which an upper limit value and a lower limit value of a characteristic for determining pass / fail are determined, and the determination of pass / fail is more accurately performed.

[0005]

According to a first aspect of the present invention, there is provided an apparatus for measuring charging characteristics of a secondary battery, comprising: means for charging a plurality of secondary batteries (power supply for charging); For detecting the current and voltage of the current (current detector, voltage detector)
Means for storing reference data of charging characteristics of the secondary battery (microprocessor); means for comparing the reference data with measurement data obtained from means for detecting individual current and voltage of the secondary battery (Microprocessor), a charging characteristic measuring apparatus for a secondary battery, comprising: means for calculating an average value from measurement data of a predetermined number of samples obtained from the means for detecting the voltage or current; Means for calculating an upper limit value and a lower limit value of the reference data from the estimated amount of the standard deviation calculated from the average value.

According to a second aspect of the present invention, there is provided an apparatus for measuring charging characteristics of a secondary battery, comprising: means for separating a secondary battery having an abnormality in the measured data from the charging means based on a comparison result of the comparing means. The configuration of the charging characteristic measuring device for a secondary battery according to claim 1, wherein:

According to a third aspect of the present invention, there is provided an apparatus for measuring charging characteristics of a secondary battery, comprising: means for acquiring data of voltage change or current change of the secondary battery having no abnormality in measured data; And means for storing the obtained data. The apparatus for measuring the charging characteristics of a secondary battery according to claim 1, further comprising:

According to a fourth aspect of the present invention, there is provided an apparatus for measuring charging characteristics of a secondary battery, comprising: a multiplexer for inputting at least one of current and voltage data of each of the plurality of secondary batteries; and the multiplexer. Means for sorting the output of each of the secondary batteries for each of the secondary batteries, means for storing the output of the multiplexer separated by the sorting means, and means for switching the output of the multiplexer for each of the secondary batteries at a constant cycle. The charge characteristic measuring device for a secondary battery according to claim 1 or claim 2 or claim 3 characterized by the following.

According to a fifth aspect of the present invention, there is provided a method for measuring charging characteristics of a secondary battery, comprising the steps of: charging a plurality of secondary batteries; detecting individual voltages or currents of the secondary batteries; Storing reference data of the charging characteristics of the secondary battery, and comparing the reference data with the measurement data obtained in the step of detecting individual voltages or currents of the secondary battery. In the characteristic measuring method, a step of calculating an average value from measurement data of a predetermined number of samples obtained in the step of detecting the voltage or the current, and a step of calculating an estimated amount of a standard deviation from the measurement data and the average value And calculating the upper limit value and the lower limit value of the reference data from the estimated amount of the standard deviation.

According to a sixth aspect of the present invention, there is provided a method for measuring charging characteristics of a secondary battery, comprising the step of disconnecting a secondary battery having an abnormality in measured data from charging means based on a result of the comparison. According to a fifth aspect of the present invention, there is provided a method for measuring charging characteristics of a secondary battery.

According to a seventh aspect of the present invention, there is provided a method for measuring a charging characteristic of a secondary battery, comprising the steps of obtaining data of a voltage change or a current change of the secondary battery having no abnormality in the measurement data, and obtaining the data. And storing the data obtained in the step (a).

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system block diagram of an apparatus for measuring the charging characteristics of a secondary battery according to the present invention. First, the secondary batteries 1a to 1d to be tested are held by a holding mechanism 2, and power is supplied from probes 3a and 3b. It has been done. The power source for charging is the charging power source 4 and the probes 3a, 3 of the holding mechanism 2 via the current control circuits 5a, 5b.
b.

A current detector 7a and a voltage detector 8a are connected to an electric path 6a between the current control circuit 5a and the probe 3a. The current detector 7a and the voltage detector 8a are connected to the charging current flowing through the secondary battery 1a. This is performed as if the charging voltage was detected. Adjacent to this, the secondary battery 1b held by the holding mechanism 2 also has the current detector 7b and the voltage detector 8b connected to the electric circuit 6b, and the charging current flowing through the secondary battery 1b and the secondary current rising with the charging are increased. This is performed as if the charging voltage of the secondary battery 1b was detected.

Although not shown here, there are 256 rechargeable batteries to be tested, which are held by the holding mechanism 2.
Charging power is supplied from a charging power supply 4 via a current control circuit provided in each of the secondary batteries, and a current detector and a voltage detector are connected to each electric circuit. The output terminals of the current detectors 7a and 7b and the voltage detectors 8a and 8b are connected to the multiplexer 9, and the output is connected to the A / D converter 10
Is input to

The multiplexer 9 is a circuit that reduces the number of output terminals and facilitates control of the device.
The data of the six rechargeable batteries is sorted, and one of the data can be selected. To select data, a selection command is issued from the control line 9a of the microprocessor 11 in accordance with the measurement program. Then, the selected data is digitized by the A / D converter 10,
The data is transmitted to the microprocessor 11 having the CPU 11a and the memory 11b therein so that the data can be stored.

The microprocessor 11 has a current control circuit 5
When an abnormality is detected in the charging characteristics of the secondary battery being measured, the current control circuits 5a and 5b are shut off and charging of the secondary battery is stopped. Further, the microprocessor 11 is connected to a host computer 13 via an interface (I / F) 12. Here, the connection means is a LAN cable 14 and is connected to the host computer 13 via the network controller 15.

The host computer 13 has a microprocessor 13a and a display 13b for displaying measurement data. The microprocessor 13a has an operation program including a command for controlling the rechargeable battery charge characteristic measuring device 16 mounted thereon. Then, commands such as charging start, voltage reading, and current reading are sent to the charging characteristic measuring device 16 of the secondary battery and operated.

The host computer 13 can perform an operation synchronized with the production system by communicating with an information processing device (for example, a host computer of a transport system) other than the charging characteristic measuring device of the secondary battery. The display 13b displays the read charging voltage value and current value, and displays the address of the secondary battery whose measurement has been stopped due to an abnormality.

Here, as shown in FIG. 2, the secondary batteries 1a and 1b are housed in a tray 17 divided into 256 squares such that the terminal electrodes face outward. The holding mechanism 2 for holding the tray 17 is, as shown in FIG.
a, 2b are opposed to each other. Probes 3a, 3b, etc., which come into contact with the terminal electrodes of the secondary batteries are provided on the opposing surfaces of the substrates 2a, 2b. , An air cylinder 2e pressing the substrate 2a,
This is like pressing the substrate 2a by 2f.

The secondary battery 1 is located between the substrates 2a and 2b.
When the tray 17 accommodating a and 1b is placed and the air cylinders 2e and 2f are operated to sandwich the substrates 2a and 2b, the terminal electrodes of the secondary batteries 1a and 1b contact the probes 3a and 3b and the like. A jumper wire 18 is connected to the probes 3a, 3b, etc., so that they can be connected to a transmission line or the like. Substrate 2a, 2b instead of jumper wire 18
May be taken out in a print pattern.

Next, the charging characteristic measuring device 1 for this secondary battery
6 will be described with reference to FIGS. When the charging is started, the secondary batteries 1a, 1b, etc. held by the holding mechanism 2 of the charging characteristic measuring device 16 of the secondary battery operate as shown in the flowchart of FIG. First, the charging start time T
= 0, and a determination reference value obtained from the result of the previous measurement is taken in through a determination step S1 of whether or not a scheduled charging time of about 7 hours has elapsed (step S1).
2). Next, one of the sample values of the charging voltage and the charging current is read (sample fetching step S3), and it is determined whether the charging characteristics are normal (pass / fail determination step S4). That is, the data read by the current detector 7a and the voltage detector 8b are combined with the multiplexer 9, the A / D converter 1
0 to the microprocessor 11. The memory 11b of the microprocessor 11 stores data of a reference charging characteristic in advance, and compares the reference data and the transmitted measurement data by the operation of the CPU 11a.

The permissible range is obtained by, for example, a statistical calculation. If the permissible range is out of the permissible range, the process exits from the loop of the processing flow as a measured value NG (step S7) (end step S8). Then, if normal, the measured charging voltage and charging current are stored in the array of the memory 11b using the time Ti as an element (recording of sample data S
5), the charging time T is counted up (step S6). This operation is performed until the charging time T (for example, 7 hours) determined for each type of the secondary battery is exceeded.

Next, when the charging time T is reached, the sample values of the charging voltage and the charging current are updated (step S9). Next, the average of the sample values is calculated (step S10). The calculation of the average value is as shown in Expression 1.

[0024]

(Equation 1)

The number n of samples is arbitrarily determined, but is, for example, 3rd to 5th. That is, replace the tray 17 five times,
If measured, five samples are obtained. Xi is the data value of each sample. Then, an estimated amount of the standard deviation is calculated from the sample data Xi and the sample average value. The arithmetic expression is, for example, as shown in Expression 2.

[0026]

(Equation 2)

When this estimated amount is calculated, it is possible to calculate a confidence interval as a criterion for pass / fail. When this confidence interval is set with, for example, a probability of 90%, the t distribution is obtained from the correspondence table (FIG. 8) corresponding to the number of samples, and
The lower limit value is obtained from the operation formula shown in Expression (4), and the upper limit value is obtained from the operation expression shown in Expression 4.

[0028]

(Equation 3)

[0029]

(Equation 4)

Then, a graph of the reference value and the actual value including the confidence intervals of the charging characteristics as shown in FIGS. 5 and 6 is created and displayed on the display 13b as required. In FIG. 5, the upper limit of the confidence interval of the voltage curve is 18a and the lower limit is 18
b, The actually measured voltage curve is indicated by 18c. The upper limit of the confidence interval of the current curve is 19a, and the lower limit is 19.
b, The actually measured current curve is indicated by 19c. The secondary battery in which an abnormality is detected during the measurement is excluded from the measurement target, but the charging characteristic of the normal secondary battery shown here falls within the upper and lower sections of the reference value.

[0031]

According to the apparatus for measuring the charging characteristics of a secondary battery according to the present invention, it is possible to reliably extract a secondary battery having an abnormality and to have a low probability that a battery having no abnormality is judged to be defective. Can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus for measuring charging characteristics of a secondary battery according to the present invention.

FIG. 2 is a perspective view of a storage tray for a secondary battery used in the secondary battery charging characteristic measuring device of the present invention.

FIG. 3 is a side sectional view of a holding mechanism used in the secondary battery charging characteristic measuring device of the present invention.

FIG. 4 is an operation flowchart of a method and apparatus for measuring a charging characteristic of a secondary battery according to the present invention.

FIG. 5 is a voltage curve of a charging characteristic.

FIG. 6 is a current curve of charging characteristics.

FIG. 7 is a voltage-current curve of charging characteristics.

FIG. 8 is a t-distribution table used for calculating a confidence interval.

[Explanation of symbols]

1a to 1d: secondary battery, 2: holding mechanism, 3a, 3b: probe, 4: charging power supply, 5a, 5b: current control circuit,
6a, 6b: electric circuit, 7a, 7b: current detector, 8a, 8
b: voltage detector, 9: multiplexer, 10: A / D converter, 11: microprocessor, 11a: CPU, 1
1b: memory, 12: interface, 13, 19a
19n: Host computer, 13a: Microprocessor, 13b: Display, 14: LAN cable, 15: Network controller, 16: Rechargeable battery charge characteristic measuring device, 17: Tray, 18: Jumper wire, 18a: Voltage curve Upper confidence interval, 18b: Lower confidence interval of voltage curve, 18c: Measured voltage curve,
19a: Upper confidence interval of current curve, 19b: Lower confidence interval of current curve, 19c: Actual measured current curve

Claims (7)

[Claims] A means for charging a plurality of secondary batteries; a means for detecting individual voltages or currents of the secondary batteries; a means for storing reference data of charging characteristics of the secondary batteries; A rechargeable battery charge characteristic measuring device comprising: means for comparing the reference data with measurement data obtained from means for detecting individual voltage or current of the secondary battery; Means for calculating an average value from the measured data of the predetermined number of samples, means for calculating an estimated amount of the standard deviation from the measured data and the average value, and an upper limit value of the reference data from the estimated amount of the standard deviation. And a means for calculating a lower limit value. 2. The secondary battery according to claim 1, further comprising a unit that disconnects the secondary battery having an abnormality in the measurement data from the charging unit based on a comparison result of the comparing unit. Charge characteristic measuring device. 3. The apparatus according to claim 2, further comprising: means for acquiring data of voltage change or current change of the secondary battery having no abnormality in the measured data; and means for storing data obtained from the data acquiring means. 2. The device for measuring charging characteristics of a secondary battery according to 1. 4. A multiplexer that inputs at least one of current and voltage data of each of the plurality of secondary batteries, a unit that separates an output of the multiplexer for each of the secondary batteries, and a classification unit. 4. The storage device according to claim 1, further comprising: a unit configured to store an output of the multiplexer that has been sorted by the unit, and a unit configured to switch an output of the multiplexer for each of the secondary batteries at a constant cycle. 5. Of the secondary battery charging characteristics. 5. A step of charging a plurality of secondary batteries; a step of detecting individual voltages or currents of the secondary batteries; a step of storing reference data of charging characteristics of the secondary batteries; In the method for measuring the charging characteristics of a secondary battery including a step of comparing the measurement data obtained in the step of detecting the individual voltage or current of the secondary battery with the reference data, the method is obtained in the step of detecting the voltage or current. Calculating an average value from measurement data of a predetermined number of samples; calculating an estimated amount of standard deviation from the measurement data and the average value; and an upper limit value and a lower limit value of reference data from the estimated amount of standard deviation. Calculating the charge characteristic of the secondary battery. 6. The method for measuring a charging characteristic of a secondary battery according to claim 5, further comprising the step of disconnecting a secondary battery having an abnormality in the measurement data from charging means based on a comparison result of the comparing step. 7. A method comprising: acquiring data of a voltage change or a current change of a secondary battery having no abnormality in the measurement data; and storing the data obtained in the data acquiring step. A method for measuring charging characteristics of a secondary battery according to claim 5.