JPH0480352B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for determining the capacity of an assembled battery, and an object of the present invention is to automatically determine the capacity of a plurality of storage batteries connected in series in a floating charge state by command while in use. shall be.

If you use a storage battery for a long time, its capacity to store electricity will decrease. In order to determine the so-called lifespan of a storage battery, the amount of electricity (ampere-hours) actually stored in the storage battery is measured by discharging it.

Conventionally, in order to measure the capacity of a storage battery used as a power source even in a floating charging state, a method has been used in which an alternative storage battery or power source is prepared and replaced.

Naturally, with this conventional method, alternative storage batteries and power sources must be prepared, and if a power outage occurs during replacement work, there is a risk that power supply to the load will be cut off.

The present invention eliminates such drawbacks, and is an uninterruptible power supply circuit in which a composition battery constituted by connecting a plurality of storage batteries in series and a load are connected in parallel to the output of a rectifier. A charging circuit is installed at both ends of one to several storage batteries to be measured selected from among them.
A discharge circuit having a current detection means connected in series is connected thereto, and an ampere-hour meter that integrates the current flowing through the discharge circuit and a voltage relay that detects the voltage of the storage battery to be measured are provided, and when the assembled battery is in a floating charging state, The discharge circuit is operated according to the operation command, and when the voltage that decreases as the discharge progresses reaches the set value of the voltage relay, the discharge circuit is stopped, and the discharge capacity is measured with the ampere-hour meter and the discharge is started. This method is characterized in that after the circuit is stopped, the charging circuit is operated to return the storage battery to be measured to the charged state.

In general, a battery pack made up of multiple storage batteries connected in series is made up of batteries from the same production lot, so there should be little variation in individual characteristics. Also,
Since they are connected in series and used for charging and discharging with the same current, it can be assumed that the degree of capacity deterioration of each storage battery is almost the same as that of each individual battery in the same battery pack.If you can select any storage battery and understand its capacity, It is possible to approximately determine the capacity of the entire assembled battery.

The present invention will be explained below with reference to the figures. Figure 1 is a configuration diagram showing an embodiment of the present invention, 1 and 1' are output terminals of a capacitance measuring device, 2 is a discharge circuit whose main component is a transistor, 3 is an ampere-hour meter, and 31
4 is a detection resistor connected in series with the discharge circuit, 4 is a charging circuit, 5 is a voltage continuation device, 6 is a sequence control circuit, and 7 is an assembled battery.

Taking a telephone exchange as an example, the storage battery constituting the assembled battery 7 is composed of 24 cells connected in series, and a rectifier 9 for floating charging and a load 10 are connected in parallel to both ends of the storage battery. When the battery to be tested is a single cell, both ends of the single cell 71 as the battery to be measured in the assembled battery 7 are connected to the output terminals 1 and 1' of the capacity measuring device, and the capacity (ampere hours) of this single cell 71 is measured.
By measuring , the life state of the entire assembled battery 7 is determined. During capacity measurement, the discharge circuit 2 is operated in response to an operation command from a push button switch or the like provided in the sequence control circuit. The discharge circuit 2 uses a transistor as a main circuit element, and is controlled by a constant current whose value can be set.

Both ends of the assembled battery 7 have a floating charging voltage (approx.
Since the voltage is controlled by the rectifier 9 so that the voltage remains constant (2.15 volts), the voltage of the single cell 71 is applied to other cells by the amount that the voltage of the single cell 71 has decreased due to the discharge of the single cell 71. The increase in charging current is less than 0.001C even when the steady state floating charging current is added. On the other hand, the discharge current used to determine the capacity of the storage battery under test is 0.1C, which is more than 100 times larger, so it can be considered to be within the margin of error for capacity determination. However, excessively large amounts of current flow into the discharge circuit 2, causing an error in the value measured by the ampere-hour meter 3. Therefore, if necessary, the current in the discharge circuit 2 should be adjusted for several seconds or longer. It is desirable to perform a so-called soft start by gradually increasing the value to the set value. Furthermore, it is also possible to gradually change the current to prevent excessive voltage fluctuations from being applied to the load 10 to the floating charging rectifier 9 when discharging is stopped, when charging is started, and when charging is stopped. be.

As the discharge progresses, the voltage of the single cell 71 decreases, and when it reaches the set value of the voltage relay 5 (usually 1.7 to 1.9 volts/cell), the discharge circuit 7 is stopped, and the discharge capacity (ampere hour) during this period is reduced to ampere. Measure with hour meter 3.

When the discharging circuit 2 is stopped, the charging circuit 4 is operated to charge the single cell 71, and the capacitance measurement process ends when the charging is completed.

The charging circuit 4 may be a known thyristor rectifier circuit, a switching regulator, a transistor series regulator, or a combination thereof.

Note that in the event that a power outage occurs during discharging of the battery under test, power is supplied to the load using other cells of the assembled battery 7, but at this time there is a risk that the single cell 71 will be charged in the opposite direction. Since this leads to deterioration of the single cell 71, if necessary, a diode 9 is connected as shown by the dotted line in FIG. 1 to suppress the voltage applied to the single cell 71 in the reverse direction to the forward voltage of the diode 8. The above applies not only to lead-acid batteries, which were explained using the power supply for telephone exchanges as an example, but also to alkaline batteries.
It can be applied not only to 48V system (24 cells) but also to 100V system circuits. Further, in the embodiment, one cell is selected as the wave measurement storage battery, but it may be configured to measure a plurality of adjacent cells.

As described above, according to the present invention, it is possible to accurately and automatically measure the capacity (ampere hours) of a storage battery that is supplying power to a load in a floating charge state while in use.

[Brief explanation of the drawing]

The figure is a wiring diagram showing an embodiment of the capacity determination method of the present invention. 2...Discharge circuit, 3...Ampere hour meter, 4
... Charging circuit, 5 ... Voltage relay, 7 ... Battery pack, 71 ... Storage battery to be measured, 9 ... Rectifier, 10
……load.

Claims (1)

[Claims] 1. An uninterruptible power supply circuit in which an assembled battery consisting of a plurality of storage batteries connected in series and a load are connected in parallel to the output of a rectifier, and one to several storage batteries to be measured selected from the assembled batteries. A charging circuit and a discharging circuit having a current detecting means connected in series are connected to both ends of the assembly. When the battery is in a floating charging state, the discharge circuit is operated, and when the voltage that decreases as the discharge progresses reaches a set value of the voltage relay, the discharge circuit is stopped and the discharge capacity is measured with the ampere-hour meter. A method for determining the capacity of an assembled battery by measuring the discharge capacity of one to several storage batteries selected from among the assembled batteries, characterized in that the charging circuit is operated after the discharging circuit is stopped and the storage battery to be measured is returned to a charged state. .