JPH09133740A - Secondary battery discharge monitor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assess the deterioration characteristic of a secondary battery installed on earth satellite. SOLUTION: A lowest voltage memory part 2 latches the lowest voltage in the discharge mode of a secondary battery 9. Also, the discharge capacity thereof is latched in a discharge capacity integration part 4, and the lowest voltage is latched in a voltage latch part 5 in the discharge mode where the prescribed discharge capacity results. Furthermore, each latched data is outputted as a monitor signal. Then data is subjected to a long-term trend assessment process and compared with simulation test results on the ground, thereby assessing the deterioration characteristic of the secondary battery 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs a trend evaluation of deterioration characteristics of a secondary battery mounted on an artificial satellite or the like.
The present invention relates to a secondary battery discharge monitor device.

[0002]

2. Description of the Related Art Conventionally, a secondary battery discharge monitor for evaluating the deterioration characteristic of a secondary battery mounted on an artificial satellite or the like has been used to evaluate the deterioration characteristic based on the trend of the minimum voltage in the discharge mode of the secondary battery. A device has been proposed (for example, Japanese Utility Model Laid-Open No. 213178/1990).

FIG. 2 is a block diagram showing a conventional secondary battery discharge monitor device. In FIG. 2, 1 is a power supply system for an artificial satellite or the like, and 2 is a minimum voltage memory unit. Power system 1
A charging mode by detecting the charging / discharging mode of the solar cell 6, the charger 7, the diode 8, and the secondary battery 9 and the secondary battery 9 that store the power generated by the solar cell 6, which generates electric power by the irradiation of the sun rays during sunshine. A charge / discharge mode detection circuit 10 for outputting a signal or a discharge mode signal and a satellite load 11 are provided.

The lowest voltage memory unit 2 is an A / D converter 12 which samples the output voltage of the secondary battery 9 at a predetermined cycle clock and outputs it as a digital voltage, and a comparator circuit which compares the digital voltage with the memory voltage. 13, a memory circuit 14 that stores the digital voltage output from the comparator circuit 13 as a memory voltage, and a memory circuit 14 that stores the signal received from the charge / discharge mode detection circuit 10 when the discharge mode signal is switched to the charge mode signal. It is provided with a latch circuit 15 for latching the stored memory voltage B, which constitutes the minimum voltage memory means.

Next, the operation of the conventional example will be described in detail with reference to FIG. In the power supply system 1, the solar cell 6 during sunshine
The electric power generated in 1 is used for charging the secondary battery 9 via the charger 7 and is simultaneously supplied to the satellite load 11 (charge mode). In the shade, the discharge current of the secondary battery 9 is supplied to the satellite load 11 via the diode 8 (discharge mode). These charge / discharge modes are detected by the charge / discharge mode detection circuit 10. The charge / discharge mode detection circuit 10 outputs a charge mode signal in the charge mode and a discharge mode signal in the discharge mode.

Next, the lowest voltage memory unit 2 samples the output voltage of the secondary battery 9 for each clock in the A / D converter 12 and outputs it as a digital voltage A. This digital voltage A is supplied to the comparator circuit 13 every clock.
In, the magnitude comparison with the memory voltage B stored in advance in the memory circuit 14 is performed.

As the initial voltage of the memory voltage B, the first digital voltage A when switching to the discharge mode is used. Then, the comparison is sequentially performed for each clock, and when A <B, A is updated and stored in the memory circuit 14 instead of B, and when A ≧ B, update storage is not performed. As a result, the memory voltage B becomes the lowest voltage in the sampled voltage value for each comparison, and the memory voltage B becomes the lowest voltage of the secondary battery 9 in the discharge mode at the end of the discharge mode (hereinafter referred to as the discharge mode lowest voltage). .)

When the discharge mode of the secondary battery 9 ends and the received signal of the latch circuit 15 is switched from the discharge mode signal to the charge mode signal, the latch circuit 15 causes the memory circuit 14 to operate.
The memory voltage B stored in is latched and output as a monitor signal. Thus, every time the discharge mode ends, the discharge mode lowest voltage in the discharge mode is output to the ground as a monitor signal. The discharge mode minimum voltage output as these monitor signals is subjected to the trend evaluation with the simulation test result of the secondary battery performed on the ground in advance to evaluate the deterioration characteristic of the secondary battery mounted on the artificial satellite or the like.

[0009]

As described above, in the conventional secondary battery discharge monitor, the deterioration characteristic of the secondary battery is evaluated by monitoring the trend of the minimum voltage in each discharge mode. However, in general, 2 in discharge mode
Since the discharge capacity value of the secondary battery is not constant, the output voltage also changes with the change of the discharge capacity value, and it is difficult to precisely evaluate the deterioration characteristics of the secondary battery by simply monitoring the minimum discharge mode voltage. There was a problem. Furthermore, in artificial satellites, the satellite load mode may change significantly depending on the operating status of the satellite and the shade rate, etc., making it difficult to compare the test results with the ground simulation test conducted in the constant load mode. There is also. The present invention is intended to solve such a problem, and an object of the present invention is to provide a secondary battery discharge monitoring device in consideration of the discharge capacity value of a secondary battery and the load mode of an artificial satellite or the like.

[0010]

In order to achieve such an object, a secondary battery discharge monitor device according to the present invention is provided with
There is provided a discharge capacity integrating means for storing an integrated capacity value obtained by time-integrating the charging current and the discharging current of the secondary battery and outputting the integrated capacity value as a monitor signal at the end of the discharge mode of the secondary battery. With such a configuration, not only the minimum discharge mode voltage of the secondary battery but also the integrated capacity value can be detected, and the long-term trend evaluation of both the minimum discharge mode voltage and the discharge capacity value becomes possible. Further, by providing the voltage latch means, it is possible to detect the minimum voltage in the discharge mode when the integrated capacity value becomes equal to or less than a predetermined value, and the test result by the ground simulation test performed under the constant load mode. It provides a means to facilitate the comparison of

[0011]

Next, details of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, 3 is a voltage memory unit, 4 is a discharge capacity integrating unit, 5 is a voltage latch unit, and 22 is a resistor. The same reference numerals as those in FIG. 2 indicate the same parts.

The discharge capacity integrating section 4 is a charge / discharge current detection circuit 16 for detecting a charge current and a discharge current of the secondary battery 9, and an A for converting the detected charge current and discharge current into a digital current for each clock. / D converter 17, charge / discharge capacity integrating circuit 1 for time integration of this digital current to obtain an integrated capacity value
8. A latch circuit 19 is provided for latching the integrated capacity value from the charge / discharge capacity integration circuit 18 and outputting it as a monitor signal when the received signal from the charge / discharge mode detection circuit 10 is switched from the discharge mode signal to the charge mode signal. The discharge capacity integrating means is constituted by these.

The voltage latch unit 5 includes a comparator circuit 20.
And a latch circuit 21 constitute a voltage latch means. The comparator circuit 20 is the charge / discharge capacity integration circuit 1
The accumulated capacity value Q _DIS is input from 8 and compared with the predetermined capacity value Q _set . If the comparison result is Q _DIS ≤Q _set , a latch signal is output to the latch circuit 21, and if Q _DIS > Q _set , no latch signal is output.

Upon receiving the latch signal from the comparator 20, the latch circuit 21 latches the memory voltage B from the memory circuit 14 and outputs it as a monitor signal. The operation of the secondary battery discharge monitor device of the present invention having the above configuration will be described in detail.

When the fluctuation of the satellite load 11 is small (for example, when the fluctuation of the load due to the operation of the satellite is small, or when the orbiting satellite is in a low orbit and the change of the shade ratio is small), the deterioration characteristic evaluation of the secondary battery Suffices to perform a trend evaluation of the minimum discharge mode voltage of the secondary battery and the integrated capacity value. The specific operation is as follows.

In the discharge mode of the secondary battery 9, the voltage of the secondary battery 9 is supplied to the lowest voltage memory unit 2 every clock, and the lowest voltage in the discharge mode is obtained and output as a monitor signal as described in FIG. At the same time, the charge current and the discharge current of the secondary battery 9 are detected by the charge / discharge current detection circuit 16 via the resistor 22 at the same clocks as described above. Since these charging current and discharging current flow in opposite directions,
If the charging current has a positive value, the discharging current can be determined as a negative value.

The detected charging current and discharging current are A /
It is supplied to the D converter 17 and converted into a digital current.
Then, the digital current is time-integrated in the charge / discharge capacity integrating circuit 18 and stored in an up / down counter (not shown) in the charge / discharge capacity integrating circuit 18. It is cumulatively stored as a positive value in the charging mode and a negative value in the discharging mode. That is, in the charging mode, the integrated capacity value increases by the charging capacity value, and when it becomes equal to the rated capacity value of the secondary battery 9, the charging is completed.

After that, in the latch circuit 19, when the received signal from the charge / discharge mode detection circuit 10 is switched from the discharge mode signal to the charge mode signal, the charge / discharge capacity integrating circuit 18 latches the integrated capacity value to serve as a monitor signal. Output. In this way, the deterioration characteristics of the secondary battery 9 are evaluated by evaluating the long-term trend of the discharge mode minimum voltage output from the latch circuit 15 and the integrated capacity value output from the latch circuit 19.

When the fluctuation of the satellite load 11 is large (for example, when the load fluctuation due to the operation of the satellite is large, when the artificial satellite is a geostationary satellite, and the shade rate greatly changes each season), in this case, the fluctuation of the satellite load The discharge capacity value of the secondary battery also changes and cannot be compared with the test results of the ground simulation test performed in the constant load mode. Therefore, the trend of the lowest voltage in the discharge mode when the discharge capacity reaches a predetermined value is evaluated and compared with the result of the ground simulation test. The discharge capacity value is the current capacity of the secondary battery 9 discharged, and is obtained by taking the difference between the known rated capacity value and the integrated capacity value of the secondary battery 9 in advance. Therefore, the same result can be obtained even if the trend evaluation of the minimum voltage in the discharge mode when the predetermined integrated capacity value is reached is performed. Therefore, the trend of the integrated capacity value is evaluated.

First, the minimum voltage memory unit 2 and the discharge capacity integrating unit 3 are operated for each clock in the same procedure as the above, and the integrated capacity value Q _{DIS of the} charge / discharge capacity integrating circuit 18 is executed.
Is supplied to the comparator circuit 20. Then, the integrated capacity value Q _DIS is compared with a preset predetermined capacity value Q _set .

When Q _DIS ≤Q _set , the comparator circuit 20
Outputs a latch signal, and when the latch circuit 21 receives the latch signal, it latches the memory voltage B stored in the memory circuit 14 and outputs it as a monitor signal. Q _DIS ＞ Q
Latch is not performed when _set . As described above, by outputting the voltage of the secondary battery 9 when the predetermined integrated capacity value is reached (equivalent to when the predetermined discharge capacity is reached) from the latch circuit 21 as a monitor signal, long-term trend evaluation is performed and deterioration occurs. Conduct characterization.

[0022]

As described above, the present invention comprises the minimum voltage memory section and the discharge capacity integrating section, and can output the discharge mode minimum voltage and the discharge capacity value of the secondary battery as the monitor signal. Therefore, when the satellite load is constant, the deterioration characteristics of the secondary battery can be evaluated more accurately than the trend evaluation using only the discharge mode minimum voltage by performing trend evaluations on the discharge mode minimum voltage and the integrated capacity value. it can. Further, by providing the voltage latch unit in the above configuration, it is possible to detect the output voltage of the secondary battery when the predetermined integrated capacity value (predetermined discharge capacity value) is reached. As a result, even if the load mode of the artificial satellite or the like fluctuates greatly and the discharge capacity value of the secondary battery is not constant, the trend of the discharge mode minimum voltage at the predetermined integrated capacity value (predetermined discharge capacity value) is evaluated to make it constant. It facilitates comparison with the results of ground simulation tests conducted in load mode.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

1 ... Power supply system for artificial satellites, 2 ... Minimum voltage memory section, 3 ...
Voltage memory section, 4 ... Discharge capacity integrating section, 5 ... Voltage latch section, 6 ... Solar cell, 7 ... Charger, 8 ... Diode, 9 ...
Secondary battery, 10 ... Charge / discharge mode detection circuit, 11 ... Satellite load, 12, 17 ... A / D converter, 13, 20 ... Comparator circuit, 14 ... Memory circuit, 15, 19, 21 ... Latch circuit, 16 ... Charge / discharge current detection circuit, 18 ... Charge / discharge capacity integrating circuit, A ... Digital voltage, B ... Memory voltage, Q _DIS
... discharge capacity value, Q _set ... predetermined capacity value.

Claims (3)

[Claims] 1. A minimum voltage memory means for storing a minimum voltage in a discharge mode of a secondary battery in which a charge mode and a discharge mode alternately change, and outputting the minimum voltage as a monitor signal at the end of the discharge mode. In the secondary battery discharge monitoring device, the integrated capacity value obtained by time-integrating the charging current and the discharging current of the secondary battery is stored, and the integrated capacity value is output as a monitor signal at the end of the secondary battery discharge mode. A secondary battery discharge monitor device comprising means. 2. The minimum voltage memory means according to claim 1, wherein the voltage of the secondary battery is sampled at every clock of a predetermined cycle, and when the voltage is smaller than the previous voltage, the content of the memory circuit is updated and stored as the minimum voltage. Then, the integrated capacitance value is compared with the specified capacitance value, and the minimum voltage at that time stored in the memory circuit is latched and output as the monitor signal when the integrated capacitance value becomes less than the specified capacitance value. A secondary battery discharge monitor device comprising latch means. 3. The charging / discharging current detecting circuit according to claim 1, wherein the discharging capacity integrating means detects a charging current and a discharging current of the secondary battery and outputs the charging current and the discharging current, and samples the charging current and the discharging current. A / D converter that outputs a digital current as a digital current, a charge / discharge capacity integrating circuit that calculates the integrated capacity value by integrating the digital current with time, and a charge / discharge capacity when the secondary battery is switched from the discharge mode to the charge mode. A secondary battery discharge monitoring device, comprising: a latch circuit that latches an integrated capacity value from an integrating circuit and outputs it as a monitor signal.