JPH0537637Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a charging/discharging circuit for a zinc-bromine battery.

B. Summary of the invention In this invention, multiple sets of batteries are installed in parallel and each battery is charged and discharged via a power conversion device, and each battery is provided with a semiconductor switch for charging and a semiconductor switch for complete discharge. In this way, even when one battery is completely discharged, another battery can be charged or discharged due to a momentary power failure.

C. Prior Art When a zinc-bromine battery is used for a long time, zinc adheres non-uniformly to its electrode plates, degrading its characteristics. For this reason, periodically reverse the polarity of the battery and discharge it.
Conditions are required to separate the zinc adhering to the electrode plates. (Hereinafter, this state will be referred to as complete discharge). By the way, if a battery is used in an actual system, for example as an uninterruptible power source, and a momentary power outage occurs during complete discharge, the polarity will be reversed and it will not be possible to take immediate action. Therefore, in order to cope with such a situation, a charging/discharging circuit as shown in FIG. 2 can be considered.
That is, when the battery 1 is divided into a plurality of sets 1a to 1n and the contactors 2a to 2n are connected to each set of batteries, and the movable piece of each contactor is connected to the contact A side, charging or complete discharge is performed through the converter 3. mode, and when connected to the contact B side, it becomes a discharge mode to the load through the inverter 4.

D Problems that the invention aims to solve If the circuit configuration is as shown in Figure 2, the batteries in other sets can be kept on standby even when some sets are completely discharged, which poses a problem when used in an actual system. However, this method requires as many contactors as there are batteries, resulting in large size and complicated switching operations.

This invention was made in view of these points,
The purpose is to provide a device of this type that is small and easy to operate.

E. Problems to be solved by the invention In a system in which multiple sets of batteries are installed in parallel and the charging and discharging of each battery is controlled via a power conversion device,
A diode is provided whose anode is connected to the positive electrode side of each battery, and whose cathode side is connected to one end of the power converter. A charging semiconductor switch is connected in antiparallel to each diode, and an anode of a complete discharge semiconductor switch is connected to the positive side of each battery, and each cathode is connected to the negative side of the converter. Connected. The positive side of the converter is connected to the negative side of each battery.

F Effect A complete discharge of a battery is achieved by turning on a semiconductor switch for complete discharge connected to the battery, which forms a closed circuit of this switch, converter, and battery and enters a complete discharge mode. When the device enters charging mode, it is sufficient to turn on a charging semiconductor switch, and discharging mode can be achieved by discharging through a diode.

G. Embodiment An embodiment of the present invention will be described below in detail based on FIG. Batteries 1a to 1n are divided into any number of groups and their negative electrode sides are connected in common, but the anodes of diodes D ₁ to _{D o} are individually connected to each positive electrode side. PC is a power conversion device, and this conversion device PC is connected between the cathode side to which each diode D ₁ to _{D o} is commonly connected and the negative electrode of the battery.
It has an inverter function that converts direct current to alternating current, and a converter function that converts alternating current to direct current.
Th ₁ to _{T o} are charging semiconductor switches connected in antiparallel to diodes D ₁ to _{D o} , respectively, and thyristors are used here. T ₁ to _{T o} are full discharge semiconductor switches made of, for example, thyristors, and the anodes of the switches T ₁ to T _o are connected to the positive electrode sides of the batteries 1a to 1n, respectively, and the cathodes are commonly connected to the converter C. connected to the negative side of The positive side of converter C is connected to the negative side of the battery.

The operation of the present invention configured as above will be explained.

First, the batteries 1a to 1n are charged by using the power converter PC as a converter function and turning on each of the charging semiconductor switches Th ₁ to _{T o} to charge the batteries 1a to 1n from the load side (charging side) → power converter PC → charging. A closed loop of semiconductor switches Th ₁ to T _o → batteries 1a to 1n → power converter PC is formed, and each battery is charged.

Next, due to long-term use of batteries, zinc adheres to their electrode plates, and when complete discharge is required, all batteries are not switched to full discharge mode at the same time, but are switched to complete discharge at a sequential time lag. For example, if you want to switch the battery 1a to full discharge, turn on the full discharge semiconductor switch _T1 and converter C, and the battery 1a will be completely discharged.
is charged to the opposite polarity through the converter C, and the battery 1a is discharged until the positive electrode side reaches zero volts, and the zinc attached to the electrode plate is removed. By sequentially turning on T _o from the semiconductor switch T ₂ in this manner, zinc adhering to the electrode plate can be removed, similar to the battery 1a.

Note that, for example, when charging other batteries 1b to 1n while battery 1a is completely discharged, if the switches Th ₂ to T _o are turned on in the same manner as described above, charging will be possible even if battery 1a is fully discharged. can.
Furthermore, if a momentary power outage occurs on the charging side while the battery 1a is completely discharged, a detection device (not shown) detects this and converts the power converter PC to an inverter function. By this, each battery 1
The charges charged in b to 1n are connected to the respective diodes.
It is discharged through D ₂ to _{D o} , converted into alternating current by the power converter PC, and supplied to the load.

H. Effects of the invention According to the invention, charging and instantaneous discharging are possible even when some batteries are completely discharged.
Moreover, the switching is performed by a combination of a diode and a semiconductor switch, which has the advantage of being compact and relatively easy to control.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing one embodiment of the present invention;
The figure is a configuration diagram of a conventional charging/discharging circuit. 1a to 1b are batteries, D ₁ to _{D o} are diodes,
Th ₁ to _{T o} are semiconductor switches for charging, T ₁ to _{T o} are semiconductor switches for complete discharge, PC is a power conversion device,
C is a converter.

Claims (1)

[Scope of utility model registration request] In a battery charging/discharging circuit that includes multiple sets of batteries arranged in parallel, charging and discharging each battery is controlled via a power converter, and a converter is provided to completely discharge each battery. A diode is connected to one end of the power converter with a common cathode, a charging semiconductor switch is connected in anti-parallel to each diode, and an anode is connected to the positive side of each battery. and the converter is connected between the cathode of each of the semiconductor switches for full discharge and the negative electrode of each battery in a polarity opposite to that of the battery. A battery charging/discharging circuit featuring: