WO2017212815A1

WO2017212815A1 - Trickle charging power supply system

Info

Publication number: WO2017212815A1
Application number: PCT/JP2017/016609
Authority: WO
Inventors: 悠宇田川; 前田　謙一; 大祐保坂; 近藤　隆文; 哲也松本; 有広櫛部
Original assignee: 日立化成株式会社
Priority date: 2016-06-06
Filing date: 2017-04-26
Publication date: 2017-12-14
Also published as: TW201743497A; JP2017220993A; JP6690414B2

Abstract

The present invention relates to a trickle charging system, a power supply system and the like, and provides a technology that can realize a higher output and a larger current discharge from a storage battery during an electrical outage than were previously possible. Provided is a trickle charging power supply system that comprises: a storage battery unit 3 that includes a nickel-zinc battery as a storage battery 30; a commercial power network; a load 2; and a charging power supply 1 that is connected to the storage battery unit 3. The trickle charging power supply system trickle charges the storage battery 30 from the charging power supply 1 as a state where the storage battery 30 is not connected to the load 2 during a normal time, and supplies direct-current power to the load 2 via a discharge from the storage battery 30 as a state in which the storage battery 30 is connected to the load 2 during a power outage. The storage battery 30 operates in an SOC range of 95-100% in the case where a fully charged state is 100%. A trickle charging voltage of trickle charging is a constant voltage within a range of 1.82-1.86 V. A maximum current of a trickle charging current is 1C.

Description

Trickle charge power supply system

The present invention relates to a technology that uses a storage battery (also called a secondary battery), and relates to a trickle charge of the storage battery, a power supply system, and the like.

There are various types of storage batteries such as lead storage batteries, nickel metal hydride batteries, and nickel zinc batteries. When the storage battery is left after being fully charged, the amount of charge power is reduced by self-discharge. In other words, the state of charge of the storage battery (SOC: State Of Charge) is in a state of a value lower than 100%.

As a system that uses a storage battery, for example, there is a power supply system that uses a storage battery to take measures in an emergency such as a power failure. This power supply system is called an emergency power supply system or a backup power supply system. In this power supply system, a storage battery is electrically connected between a charging power supply connected to a commercial power system and a device as a load. This power supply system normally operates a device that is a load based on AC power from a commercial power system, while charging a storage battery from a power source for charging, and discharges from the storage battery to a device that is a load during a power failure. To supply power.

As a method for charging a storage battery, a float charging method or a trickle charging method can be given. The float charging method is a method in which a storage battery is charged at a constant voltage in a system in which a storage battery is electrically connected in parallel to a charger as a charging power source and a load. This charging power source is used for both power supply to the load and charging of the storage battery. The storage battery is always applied with a voltage even in a fully charged state, and a current flows through the storage battery in accordance with a decrease in the amount of charge due to self-discharge of the storage battery, so that the fully charged state is maintained.

The trickle charging method is a method in which a storage battery is charged with a minute current in a system in which the storage battery is electrically connected between a charger as a charging power source and a load. In this system, normally, a device as a load is operated from a charging power source based on AC power of a commercial power system. On the other hand, the storage battery is charged with a minute current from the charging power source in a state where the storage battery is electrically disconnected from the load. At this time, in the trickle charging method, charging is continuously performed with a minute current of, for example, about 0.001 C to 0.1 C in order to compensate for the decrease in charging power from the fully charged state due to the self-discharge of the storage battery. Thereby, the fully charged state of the storage battery is maintained. In this system, at the time of a power failure, that is, when the AC power supply from the commercial power system is interrupted, the storage battery is connected to the load, and the power from the discharge from the storage battery is supplied to the load. As a result, the operation of the equipment that is a load at the time of a power failure is continued and the system operation is continued. The configuration of such a trickle charging system, for example, a trickle charging system that performs trickle charging for a lead-acid battery, is well known.

Patent No. 5514594 (patent document 1) is mentioned as a prior art example regarding charge of a storage battery. Patent Document 1 describes that a float charge system for a nickel metal hydride battery performs float charge on the nickel metal hydride battery, and particularly determines that a float charge current value is determined according to the storage battery state.

Japanese Patent No. 5514594

As a result of the reduction in the amount of charge power due to the self-discharge of the storage battery, there may be a case where sufficient discharge power cannot be taken out from the storage battery when necessary. For example, in the above power supply system, in the event of an emergency such as a power failure, when the storage battery charge power amount and SOC are low, there is a possibility that sufficient power required by the load cannot be supplied from the storage battery by discharging. is there. In order to reduce the possibility, it is desirable to keep the storage battery fully charged in the power supply system or the like. For this purpose, a mechanism for suitably charging the storage battery and maintaining a fully charged state in a power supply system or the like is necessary. As the mechanism, a trickle charging method or the like is applied in a power supply system or the like.

Conventionally, trickle charging systems that perform trickle charging of lead-acid batteries and emergency power supply systems that use lead-acid batteries are common. However, in an emergency power supply system including the trickle charging system, an inexpensive lead storage battery can be used, but the discharge of the lead storage battery has a low output and a large current discharge cannot be realized. Therefore, the system may not be able to supply sufficient power to the load during a power failure. That is, the trickle charge system and power supply system of the prior art have problems with respect to trickle charge and discharge output of the storage battery.

An object of the present invention is to provide a technology capable of realizing a higher output and higher current discharge from a storage battery at the time of a power failure with respect to a trickle charging system including a storage battery and a power supply system. Another object of the present invention is to provide a technique capable of realizing such a discharge function and preventing the overcharge or the like while extending the life of the storage battery as much as possible, that is, maintaining the discharge function for a long period of time. . Another object of the present invention is to provide a technique capable of realizing cleanness in the environment at a lower cost, space saving and higher safety than the conventional one while realizing such a discharge function.

A representative embodiment of the present invention is a trickle charge power supply system that is a power supply system including a trickle charge system, and has the following configuration.

A trickle charge power supply system according to an embodiment includes a storage battery unit including a nickel-zinc battery as a storage battery, a commercial power system, a load, and a charging power source connected to the storage battery unit. The storage battery is not connected to the load, and based on the AC power of the commercial power system, trickle charging is performed on the storage battery of the storage battery unit by DC power from the charging power source. At the time of a power failure when AC power is interrupted, the storage battery of the storage battery unit is connected to the load, and DC power is supplied from the storage battery of the storage battery unit to the load, and the storage battery is fully charged. When it is 100%, it is operated in the SOC range of 95% or more and 100% or less, and the trickle charge voltage of the trickle charge is 1 A constant voltage in the range of up to 1.86V or 82V, the maximum current trickle charge current is 1C.

According to a typical embodiment of the present invention, regarding a power supply system that performs trickle charging using a storage battery, power supply to a load can be realized by discharging the storage battery with as high output and large current as possible at the time of a power failure. In addition, according to a typical embodiment of the present invention, such a discharge function is realized, and the life of the storage battery can be extended as long as possible while preventing overcharging, that is, the discharge function is maintained for a long period of time. it can. In addition, according to a typical embodiment of the present invention, it is possible to realize cleanness in the environment with as low cost, space saving and high safety as possible while realizing such a discharge function.

It is a figure which shows the structure of the trickle charge power supply system of embodiment of this invention. It is a figure which shows the structural example of a storage battery part in the trickle charge power supply system of embodiment. It is a figure which shows the table | surface which put together the control conditions and the result in a test example and a comparative example in the trickle charge power supply system of embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

[Issues]
A supplementary explanation of the above-described problems will be given. There are various storage batteries such as a lead storage battery and a nickel metal hydride battery as candidate storage batteries for use in the trickle charge power supply system. Various storage batteries have characteristics including advantages and disadvantages.

Conventionally, storage batteries that can be used for trickle charging and float charging have been almost limited to lead storage batteries and the like. The reason is as follows. As lead-acid batteries are charged, the internal resistance increases. From this, even if a lead storage battery continues to be charged at a constant voltage in a fully charged state, almost no current flows to the lead storage battery. In the trickle charging method, only a minute current flows as described above. Therefore, the lead storage battery is less affected by the decrease in battery life due to overcharging, and can be fully charged for a long period of time.

Lead acid batteries have advantages such as low cost and excellent stability compared to other batteries. The lead storage battery, on the other hand, has disadvantages such as a small charge / discharge current, that is, low output. The lead-acid battery is suitable for long-time use, for example, an emergency power system for a specific load with a small load fluctuation amount. Since lead-acid batteries have a small discharge current, they are not suitable for applications that require a large current discharge. In order to realize a large current discharge using a lead storage battery, the required capacity becomes large. As a result, a large installation space is required, resulting in high cost.

Nickel metal hydride batteries have advantages such as a larger charge / discharge current than lead acid batteries. However, nickel-metal hydride batteries have low energy density and large self-discharge. Moreover, the cost per unit capacity (kwh) of a nickel metal hydride battery is higher than that of a lead battery. For this reason, in the case of installation of a large-capacity nickel metal hydride battery, the cost becomes great. In addition, nickel-metal hydride batteries are also required to prevent overdischarge and overcharge.

On the other hand, a nickel zinc battery is known as a storage battery capable of discharging at a high output. The nickel zinc battery is an alkaline secondary battery in which the negative electrode material of the nickel metal hydride battery is changed to zinc. The nickel zinc battery can be charged and discharged at a higher current value than the lead acid battery. Nickel zinc batteries have high energy density and low self-discharge. Since the nickel zinc battery has a battery voltage about 0.4 V higher than that of the nickel metal hydride battery, the energy density per volume is 1.4 times larger. Nickel zinc batteries are superior in cost to nickel hydrogen batteries. The nickel-zinc battery is highly safe because a water-based electrolyte is used in the same manner as lead-acid batteries and nickel-metal hydride batteries. Zinc of the negative electrode of the nickel-zinc battery is excellent in environmental compatibility and material cost, so that a small, lightweight, and inexpensive system can be configured. Further, similarly to the nickel-metal hydride battery, the nickel-zinc battery can absorb oxygen generated from the positive electrode by overcharging at the negative electrode.

Nickel-zinc batteries have been slow to spread as storage batteries because they have faded in terms of cycle life due to dendrites. Recently, research and development of nickel-zinc batteries with a long cycle life with reduced dendrites is underway.

In addition, since the float charge system like patent document 1 uses a nickel metal hydride battery, compared with a lead storage battery, the energy density per volume is twice as large and can comprise a small and lightweight system. However, when a trickle charge system using a nickel metal hydride battery is configured, the cost becomes high as described above.

Note that alkaline storage batteries using nickel electrodes, such as nickel-zinc batteries, have a problem in terms of charging efficiency because charging reaction and oxygen generation reaction occur in a trickle charge. The problem is particularly remarkable in the case of trickle charging at a high temperature. Here, the high temperature is a temperature higher than room temperature of about 30 to 60 ° C. When a large amount of oxygen generation reaction due to overcharging occurs in the storage battery, the electrolytic solution decreases, the internal resistance increases, and finally discharge becomes impossible.

The adoption of the trickle charging method is as follows. In an emergency power supply system or the like, when the storage battery is kept in a fully charged state for a long period of time, the amount of power stored in the storage battery is reduced due to the self-discharge of the storage battery, and the SOC value is lowered. Therefore, when using the discharge of the storage battery in the event of an emergency such as a power failure after a long period of time, the rated performance may not be exhibited and may not be used. Therefore, it is preferable to perform trickle charging in order to compensate for the power reduction due to the self-discharge of the storage battery and keep the storage battery in a fully charged state. In trickle charging, when the SOC of the storage battery approaches a fully charged state, the trickle charging current naturally decreases. Therefore, the trickle charging method is effective in preventing overcharge of the storage battery.

Based on the above-mentioned problems and the like, the trickle charge power supply system of the embodiment is configured. In the trickle charge power supply system of the embodiment, a nickel zinc battery is newly applied as a storage battery, and the trickle charge for the storage battery is performed. The trickle charge power supply system according to the embodiment has a configuration in which suitable trickle charge control, control conditions, and the like are designed so that the preferred trickle charge of the nickel zinc battery can be performed. Thereby, the trickle charge power supply system of the embodiment realizes higher output and higher current discharge than the conventional system, and maximizes the life of the nickel zinc battery.

[the term]
The terms are as follows. CA is a unit representing the charge / discharge characteristics of a storage battery. C in CA is a unit representing the discharge rate of the storage battery, and A represents a unit such as an ampere representing a current value. The discharge rate is a relative ratio of current during discharge to battery capacity. The battery capacity indicates the amount of electricity that can be discharged and taken out before the end of discharge, and its unit is Ah (ampere hour) or the like. 1C indicates a current value at which discharge of a single cell having a capacity of a nominal capacity value is constant-current discharged and discharge is completed in one hour. 1CA indicates a current value that actually flows in the case of 1C.

[Trickle charge characteristics]
The charging characteristics of general trickle charging will be described in detail below. During trickle charging, in the first short period (for example, 1 hour), as constant current charging, the voltage value is gradually increased from a voltage value such as 1 V so as to maintain a constant current value such as 0.2 C, for example. To be controlled. When the voltage value reaches a constant voltage value such as 1.86 V in order to prevent overcharging, the voltage value is maintained within a range near the constant voltage value as constant voltage charging for a long period thereafter. To be controlled. During that period, the current value decays from the initial constant current value, for example, becomes a minute current such as 0.001 C, and charging is continued with the minute current.

In trickle charging, charging is performed over a long period of time, so the effect of the charging voltage value on the life is large, so it is necessary to pay attention to the charging voltage value. In addition, since the charging characteristics are affected by temperature, it is necessary to pay attention to the temperatures of the storage battery and the charger unit. The type and capacity of the storage battery need to be designed according to the time of power failure, that is, the time of discharge and the power consumption of the load.

(Embodiment 1)
A trickle charge power supply system according to an embodiment of the present invention will be described with reference to FIGS.

[Trickle charge power supply system]
FIG. 1 shows a configuration of a trickle charge power supply system according to an embodiment. The trickle charge power supply system of the embodiment is a system connected to a commercial power system and a load 2 and includes a trickle charge system 10, a power failure detection relay unit 4, a switch 5, and the like. The trickle charging system 10 is a system that performs trickle charging, and includes a charging power source 1 and a storage battery unit 3. The load 2 is a device or system that becomes an electrical load.

The trickle charging system 10 is normally in a standby state, that is, in a state where trickle charging is performed from the charging power source 1 to the storage battery 30 in order to prepare for a power failure or the like.

In other words, the charging power source 1 is a charger unit, and the input side is connected to the terminal unit 6 of the commercial power system through an AC electric wire 71. The output side of the charging power source 1 is connected to the load 2 through the DC electric wire 72. Further, the charging power source 1 is connected to the storage battery unit 3 through a DC electric wire 73.

The terminal unit 6 inputs AC power from the commercial power system and outputs it to the charging power source 1. The power failure detection relay unit 4 is connected to the AC wire 71 through the wire 75. The power failure detection relay unit 4 includes a relay circuit and detects a power failure state as a supply state of AC power of the commercial power system. The power failure detection relay unit 4 is connected to the switch 5 through a signal line, and switches the switch 5 between an on state and an off state by a control signal 81 to be output. The power failure detection relay unit 4 gives an off signal for turning off the switch 5 as the control signal 81 in the normal state, that is, the time during which the non-power failure state is detected. The power failure detection relay unit 4 gives an ON signal for turning on the switch 5 as the control signal 81 during the time when the power failure state is detected.

The charging power source 1 includes an inverter that is a conversion circuit that converts AC power from a commercial power system into DC power. Further, the charging power source 1 includes a control circuit for performing trickle charging of the storage battery 30 of the storage battery unit 3.

A DC electric wire 74 from the storage battery unit 3 is connected to the DC electric wire 72 between the charging power source 1 and the load 2. The DC power 103 from the charging power source 1 and the storage battery unit 3 is input to the load 2 as a load input through the DC wire 72 and the DC wire 73.

In the DC electric wire 73 between the charging power source 1 and the storage battery unit 3, DC power is normally supplied from the charging power source 1 to the storage battery 30 of the storage battery unit 3. That is, charging 101 for the storage battery 30 of the storage battery unit 3 is performed by the DC current of the DC power.

The DC power line 74 outputs DC power from the storage battery 30 of the storage battery unit 3 at the time of a power failure. That is, the discharge 102 from the storage battery 30 is performed by the direct current of the direct-current power. The electric power of the discharge 102 is supplied as DC power 103 to the load 2 through the DC electric wire 74.

A switch 5 is provided in the middle of the DC electric wire 74. The switch 5 is switched between an on state and an off state based on a control signal 81 input to the control terminal. Normally, when the switch 5 is in the OFF state, the DC electric wire 74 is not connected to the DC electric wire 72, so that the discharge 102 from the storage battery 30 is not performed. At the time of the power failure, during the time when the switch 5 is on, the DC electric wire 74 is connected to the DC electric wire 72, so that the discharge 102 from the storage battery 30 is performed.

The storage battery unit 3 includes a storage battery 30. The storage battery 30 is constituted by a nickel zinc battery. The storage battery unit 3 receives charge 101 which is trickle charge from the charging power source 1 at normal times, and discharges 102 to the load 2 at power failure.

In the trickle charge power supply system, normally, the storage battery 30 is disconnected from the load 2 device, that is, the switch 5 is turned off. Then, the storage battery 30 of the storage battery unit 3 is charged 101 from the charging power source 1 with a small current, for example, 0.001 to 0.1 C as a trickle charging current. By this trickle charge, the storage battery 30 is held in a fully charged state. When a power failure from the commercial power system is interrupted, the trickle charge power supply system detects a power failure by the power failure detection relay unit 4 and turns on the switch 5 so that the storage battery 30 is connected to the load 2. Then, discharging 102 is performed from the storage battery 30 of the storage battery unit 3, and the electric power is supplied to the load 2 as DC power 103. As a result, supply of the DC power 103 with a sufficient amount of discharged power from the storage battery 30 is realized, and the operation of the device that is the load 2 is continued during a power failure.

Thereby, the trickle charge power supply system according to the embodiment realizes high output and large current discharge as compared with a trickle charge power supply system using a conventional lead storage battery. In addition, the trickle charge power supply system of the embodiment prevents overcharge of the storage battery 30 and maximizes the life of the storage battery 30 by the trickle charge method. Further, the trickle charge power supply system according to the embodiment realizes an inexpensive system as compared with a system using a conventional nickel metal hydride battery or the like. In addition, the trickle charge power supply system of the embodiment realizes a system that is safer and more environmentally friendly than a system using a conventional nickel metal hydride battery or the like.

[Storage battery section]
FIG. 2 shows a configuration of the storage battery unit 3 in the embodiment. The storage battery unit 3 has a configuration in which nickel zinc batteries that are a plurality of storage batteries 30 are connected in series. In the storage battery unit 3, a plurality of single cells are connected in series, whereby an assembled battery is configured. In the storage battery unit 3, a DC electric wire 73 and a DC electric wire 74 are connected to a plurality of storage batteries 30 through a storage battery control unit 31. A positive electrode terminal is provided on the uppermost potential side of the battery pack of the storage battery 30 and is electrically connected to the DC electric wire 73 and the DC electric wire 74. A negative electrode terminal is provided on the lowest potential side of the assembled battery and is connected to the ground.

The storage battery control unit 31 adjusts and controls states of currents and voltages of the plurality of storage batteries 30.

Further, a storage battery state detection unit 32 is connected to a plurality of storage batteries 30 through a storage battery control unit 31. The storage battery state detection unit 32 measures and detects states such as current, voltage, and temperature of the plurality of storage batteries 30. Further, the storage battery state detection unit 32 may detect the SOC value of the storage battery 30 of the storage battery unit 3 by calculation based on the current, voltage, temperature, and the like of the plurality of storage batteries 30. The trickle charging system 10 may determine normality / abnormality of the storage battery 30 using the detection value of the storage battery state detection unit 32 of the storage battery unit 3. Trickle charging system 10 may determine the fully charged state of storage battery 30 using the SOC value of the detected value, and execute control according to the state. Examples of the control include control for stopping the charging 101 and the discharging 102 according to the SOC value.

[Modification of storage battery section]
As a modification, the storage battery unit 3 is not limited to a configuration in which the plurality of storage batteries 30 are connected in series, but may be configured in a parallel connection of the plurality of storage batteries 30. In addition, the storage battery unit 3 may have both a series connection and a parallel connection, that is, a structure in which a plurality of assembled batteries are connected in parallel. Any form is possible, and what is necessary is just to select according to designs, such as required storage battery capacity.

[Nickel zinc battery]
The detailed configuration example of the nickel zinc battery used as the storage battery 30 is as follows. The nickel-zinc battery has nickel (Ni) at one electrode of the positive electrode or the negative electrode, zinc (Zn) at the other electrode of the positive electrode or the negative electrode, and an electrolytic solution made of an alkaline aqueous solution.

The nickel electrode includes, as a component and a manufacturing method, an additive, a binder, and the like with respect to an active material mainly composed of nickel hydroxide particles. The nickel hydroxide particles may be solid-solved with cobalt, zinc, cadmium, or the like, or the surface may be coated with a cobalt compound. As the additive, in addition to cobalt oxide, cobalt compounds such as metal cobalt and cobalt hydroxide, rare earth compounds such as zinc compounds such as metal zinc, zinc oxide, and zinc hydroxide can be used. As the binder, a hydrophilic or hydrophobic polymer or the like can be used. More specifically, the binder may be at least one selected from hydroxypropyl methylcellulose (HPMC), carboxymethylcellulose (CMC), and sodium polyacrylate (SPA). The binder is preferably 0.01 parts by mass or more and 0.5 parts by mass or less with respect to 100 parts by mass of the positive electrode active material particles, for example.

The zinc electrode includes at least zinc oxide, zinc, polytetrafluoroethylene, and the like as constituent elements and manufacturing methods. Examples of the alkaline aqueous solution include an aqueous potassium hydroxide solution. A hydrophilic microporous membrane is used as the separator between the positive electrode and the negative electrode.

The nickel zinc battery is a single cell, for example, having a nominal voltage of 1.65V and a full charge voltage of 1.9V.

In order to extend the charge / discharge cycle life of the nickel-zinc battery, for example, it is necessary to change the shape of the negative electrode, aggregate, suppress dendrite, improve the conductivity of the negative electrode, and the like. Examples of effective countermeasures for this purpose include the following. That is, calcium, hydroxide, fluoride, and phosphoric acid are added as the negative electrode active material. Add phosphoric acid, fluoride, and carbonate to the electrolyte. Use a polyolefin microporous membrane for the separator. Add bismuth, lead, carbon, etc. as the negative electrode active material.

[Trickle charge voltage and trickle charge current]
FIG. 2 shows a trickle charge voltage V1 and a trickle charge current I1 when trickle charging the storage battery 30. In the embodiment, as a definition, the trickle charge voltage refers to a voltage per nickel zinc battery that is the storage battery 30, that is, a voltage per unit cell.

Trickle charge voltage V1 is set to an appropriate value so that overcharge of storage battery 30 can be prevented. In the embodiment, the trickle charge voltage V1 is set to a constant voltage value in the range of 1.82 V or more and 1.86 V or less as the trickle charge characteristics and control conditions (Test Examples 1 to 5 described later). See). The trickle charge voltage V1 is preferably a constant voltage value in the range of 1.84 V to 1.86 V from the viewpoint of battery life and performance (see Test Examples 3 to 5 described later). ). The trickle charge voltage V1 is further set to 1.85 V as a preferable value from the range (see Test Example 4 described later).

As a modification, a current limiting circuit or the like may be provided in the trickle charging system 10 to limit the trickle charging current I1 with a predetermined upper limit value. Thereby, the life shortening of the storage battery 30 due to an excessive current is prevented.

In the embodiment, the current value of the trickle charge current I1 is set to 1 C or less as a preferable condition. Here, 1C is a current value at which discharge of a nickel-zinc battery cell having a nominal capacity is constant-current discharged and the discharge is completed in one hour. The current value of the trickle charging current I1 is more preferably 0.5C, and still more preferably 0.2C.

[SOC management]
When performing trickle charging of a nickel zinc battery, from the viewpoint of battery life and performance, the SOC range is preferably in the range of 80% to 100% with the fully charged state being 100%. In the trickle charge power supply system of the embodiment, the SOC of the nickel-zinc battery that is the storage battery 30 is set to 95% to 100% as the SOC range. That is, in the SOC range, the upper limit is 100%, which is a fully charged state, and the lower limit is 95%, which is a state close to that. The trickle charging system 10 performs control so that the SOC value of the storage battery 30 is within the SOC range during normal operation.

As a modification, it may be managed in a range other than the SOC range (for example, a range of 80% to 95%).

[Control of Trickle Charging and Control Conditions-Examples]
Control of trickle charging from the charging power source 1 to the storage battery unit 3 in the trickle charging system 10 and its control conditions are as follows. The trickle charge power supply system of the embodiment is designed based on an example of a trickle charge test described below regarding control of trickle charge.

FIG. 3 shows a table summarizing the control conditions and results in the test example and the comparative example in the trickle charge power supply system of the embodiment. As trickle charge tests, Test Examples 1 to 5 are shown. Further, Comparative Examples 1 and 2 are shown for Test Examples 1 to 5. In the embodiment, Examples 1 to 5 are configured based on Test Examples 1 to 5.

In the table, the identification names of the test example and the comparative example, test temperature [° C.], trickle charge voltage [V], initial capacity [%], third capacity retention rate [%], and sixth capacity retention rate are arranged in order as columns. [%] Shows the results. “Initial capacity” or the like is represented by the SOC value of the storage battery. The “third capacity maintenance rate” represents, for example, a rate at which the capacity of the storage battery is maintained from the initial capacity after about six months after the third trickle charge cycle. The “sixth capacity retention rate” represents a similar rate after about one year, for example, after the sixth trickle charge cycle. The values in the “Result” column are the evaluation values of the test examples and comparative examples of each trickle charge characteristic, and in particular, the evaluation values for the value of the “sixth capacity retention rate”. This result value indicates that the double circle (◎) was 70% or more as its value. Similarly, a circle (◯) indicates 60% or more and less than 70%, a triangle (Δ) indicates 50% or more and less than 60%, and a cross (x) indicates less than 50%.

In the test example, a nickel zinc battery of 8 Ah-1.65 V (nominal voltage value) was used as a storage battery. In the nickel-zinc battery, nickel hydroxide was used for the positive electrode and zinc oxide was used for the negative electrode. The capacity ratio (N / P) between the negative electrode and the positive electrode was 2.5. As a separator between the positive electrode and the negative electrode, a hydrophilized polypropylene nonwoven fabric and PP / PE were used. As the electrolytic solution, KOH (5M) was used.

The storage battery configured in the test example was subjected to chemical conversion treatment at room temperature of 25 ° C. As chemical formation conditions, after charging for about 1.5 hours at 1 C as a charging current, an operation of discharging at 1 C and 1.9 V as a cutoff voltage was performed. After this operation, the result of measuring the internal resistance of the storage battery with a milliohm meter was 0.0016Ω (1.6 mΩ). Next, the nickel zinc battery thus obtained was charged at a constant voltage until the charging current reached 1 C, the charging voltage 1.90 V, and the cut-off current 0.05 C. As a result, the nickel zinc battery was fully charged, that is, the SOC value was 100%.

In each test example and comparative example, each of the nickel-zinc batteries that were in a fully charged state as an initial capacity was subjected to a test of trickle charging for a plurality of cycles using a charge / discharge test apparatus. In either case, the test temperature was 45 ° C., which was a high temperature. In either case, constant voltage charging with 60 days as one cycle, that is, trickle charging was performed during that period so as to be held at a constant voltage value in the vicinity of the set trickle charging voltage. All were carried out as a constant current discharge under the conditions of a discharge current value of 0.25 C and a cut-off voltage of 1.1 V for 6 cycles, that is, about one year.

[Example 1 (Test Example 1)]
In Example 1, which is Test Example 1, as shown in the table, the trickle charge voltage was set to 1.82 V and the maximum current of the trickle charge current was set to 0.2 C for the nickel zinc battery. One cycle of constant voltage charging was performed while the trickle charging voltage was 1.82V. The constant current discharge cycle was performed 6 times under the above conditions.

[Example 2 (Test Example 2)]
In Example 2, which is Test Example 2, the trickle charge voltage was set to 1.83 V and the maximum trickle charge current was set to 0.2 C for the nickel zinc battery. The constant voltage charge of 1 cycle was performed with the trickle charge voltage kept at 1.83V. The constant current discharge cycle was performed 6 times under the above conditions.

[Example 3 (Test Example 3)]
In Example 3 as Test Example 3, the trickle charge voltage was set to 1.84 V and the maximum current of the trickle charge current was set to 0.2 C for the nickel zinc battery. The constant voltage charge of 1 cycle was performed with the trickle charge voltage being 1.84V. The constant current discharge cycle was performed 6 times under the above conditions.

[Example 4 (Test Example 4)]
In Example 4 which is Test Example 4, the trickle charge voltage was set to 1.85 V and the maximum current of the trickle charge current was set to 0.2 C for the nickel zinc battery. One cycle of constant voltage charging was performed while the trickle charging voltage was 1.85V. The constant current discharge cycle was performed 6 times under the above conditions.

[Example 5 (Test Example 5)]
In Example 5 which is Test Example 5, the trickle charge voltage was set to 1.86 V and the maximum current of the trickle charge current was set to 0.2 C for the nickel zinc battery. The constant voltage charge of 1 cycle was performed with the trickle charge voltage being 1.86V. The constant current discharge cycle was performed 6 times under the above conditions.

[Comparative Example 1]
In Comparative Example 1, for the nickel zinc battery, the trickle charge voltage was set to 1.81 V, and the maximum current of the trickle charge current was set to 0.2 C. One cycle of constant voltage charging was performed while the trickle charging voltage was 1.81V. The constant current discharge cycle was performed 6 times under the above conditions.

[Comparative Example 2]
In Comparative Example 2, for the nickel zinc battery, the trickle charge voltage was set to 1.87 V, and the maximum current of the trickle charge current was set to 0.2 C. One cycle of constant voltage charging was performed while the trickle charging voltage was 1.87V.

[Result (Evaluation of trickle charge characteristics)]
The results of evaluation of the trickle charge characteristics of the test example and the comparative example are as shown in the “Result” column of the table of FIG. A value such as “sixth capacity retention rate” corresponds to a value of the discharge capacity, which is the capacity of the storage battery after constant-current discharge under the above conditions (0.25 C) after constant-voltage charging in each cycle. In particular, the discharge capacity before the trickle charge test is taken as 100% as the initial capacity, and the values of the third and sixth discharge capacities are shown.

In Test Example 1, constant voltage charging was performed at 45 ° C. for about one year, but the discharge capacity was maintained at 50% or more. The sixth capacity retention rate was 51%. In the trickle charge test of this nickel zinc battery, the current value was charged with a small current of about 0.0100 C by controlling the charge voltage to 1.82 V (= tricle charge voltage). As a result, it became clear that the nickel-zinc battery can maintain its capacity without being overcharged or insufficiently charged.

In Test Example 2, constant voltage charging was performed for about one year in the same manner, but the discharge capacity was maintained at 50% or more. The sixth capacity retention rate was 58%. By controlling to a charging voltage of 1.83 V, the current value was charged with a small current of about 0.0125 C. As a result, it has been clarified that the capacity of the nickel zinc battery can be maintained.

In Test Example 3, constant voltage charging was performed for about one year in the same manner, but the discharge capacity was maintained at 60% or more. The sixth capacity retention rate was 68%. By controlling to a charging voltage of 1.84 V, the current value was charged with a current of about 0.0140 C, which is a small value. As a result, it has been clarified that the capacity of the nickel zinc battery can be maintained.

In Test Example 4, constant voltage charging was performed for about one year in the same manner, but the discharge capacity was maintained at 70% or more. The sixth capacity retention rate was 72%. In this test, by controlling to a charging voltage of 1.85 V, the current value was charged with a small current of about 0.0165 C. As a result, it has been clarified that the capacity of the nickel zinc battery can be maintained.

In Test Example 5, constant voltage charging was similarly performed for about one year, but the discharge capacity was maintained at 60% or more. The sixth capacity retention rate was 65%. In this test, by controlling to a charging voltage of 1.86 V, the current value was charged with a current of about 0.0178 C which is a small value. As a result, it has been clarified that the capacity of the nickel zinc battery can be maintained.

In Comparative Example 1, constant voltage charging was similarly performed for about one year, but the discharge capacity was 50% or less. The sixth capacity retention rate was 38%. In this test, by controlling to a charging voltage of 1.81 V, the current value was charged with a small current of about 0.0090C. However, it became clear that the capacity of the nickel zinc battery could not be maintained due to insufficient charging.

In Comparative Example 2, constant voltage charging was similarly performed for about one year. However, since the voltage of the storage battery decreased to about 0.3 V after about one year, the discharge capacity could not be measured. By controlling to a charging voltage of 1.87 V, a current of about 0.051 C, which is a large current value, continued to flow, and it became clear that the capacity of the storage battery could not be maintained due to overcharging.

Suppose 50% of the nominal capacity is defined as the battery life. In that case, in Comparative Example 1, the battery life is 9 months. In Comparative Example 2, the battery life is 8 months when the discharge capacity was measurable.

The battery life of the test example is estimated by simple calculation as follows. That is, in Test Example 1, it is one year. In Test Example 2, it is one year and two months. In Test Example 3, it is one year and seven months. In Test Example 4, it is 1 year and 10 months. In Test Example 5, it is 1 year and 6 months. In Test Examples 1 to 5, trickle charging can be performed during each battery life.

In addition, this test was a trickle life test at a high temperature of 45 ° C. If it is defined that the rate of battery deterioration due to a temperature of 10 ° C. is doubled, the battery life at room temperature of 25 ° C. can be estimated as follows. That is, in Test Example 1, it is 4 years. In Test Example 2, it is 4 years and 8 months. In Test Example 3, it is 6 years and 4 months. In Test Example 4, it is 7 years and 4 months. In Test Example 5, it is 6 years. In Test Examples 1 to 5, trickle charging can be performed during each battery life.

As shown in the table, in Test Example 4, the capacity retention rate at the sixth time in about one year was 72%, which is 70% or more, so the result value was a double circle (◎), the most suitable. Evaluated that there was. Test Example 4 is adopted as the most preferred embodiment. In Test Example 3 and Test Example 5, since the sixth capacity retention rate was 60% or more and less than 70%, the value of the result was a circle (◯), and it was evaluated that it was suitable. Test Example 3 and Test Example 5 are employed as preferred embodiments. In Test Example 1 and Test Example 2, since the sixth capacity retention rate was 50% or more and less than 60%, the value of the result was set as a triangle (Δ) and evaluated as possible. Although Test Example 1 and Test Example 2 are less effective than Test Examples 3, 4, and 5, they have sufficient effects and are employed as embodiments.

In Comparative Example 1 and Comparative Example 2, since the 6th capacity retention rate was less than 50% (particularly less than 40%) or measurement was impossible, the result value was evaluated as “unsatisfactory” (×). Since Comparative Example 1 and Comparative Example 2 have low effects, they are not adopted as the embodiments.

As a result of the above-described test, the inventors have examined from Examples 1 to 5 corresponding to Test Examples 1 to 5, and the trickle charge voltage V1 in the trickle charge power supply system of the embodiment ranges from 1.82 V to 1. 86V was obtained. As in the comparative example, outside the range of the trickle charge voltage V1, the sixth capacity retention rate was particularly less than 40% or could not be measured, but within this range, 50% or more, particularly 70% in Example 4. That's it. That is, within the range of the trickle charge voltage V1, a significantly superior effect and a more preferable effect were obtained as compared with outside the range. That is, the trickle charge power supply system of the embodiment set to the trickle charge voltage V1 within the range of Examples 1 to 5 has a sufficient capacity maintenance rate of the storage battery 30 after performing trickle charge and discharge for a long time. The effect is high and the battery life is long.

[Effects]
As described above, according to the trickle charge power supply system of the embodiment, it is possible to supply power to a load by discharging a high output and a large current from a storage battery at the time of a power failure, compared to a power supply system using a conventional lead storage battery or the like. A certain discharge function can be realized. In addition, according to the embodiment, such a discharge function can be realized and the life of the storage battery can be made as long as possible while preventing overcharge of the storage battery, that is, the discharge function can be maintained for a long period of time. Further, according to the embodiment, while realizing such a discharge function, it is possible to realize that the environment is clean with lower cost, space saving, and higher safety than in the past.

The trickle charge power supply system of the embodiment is a system in which a trickle charge system for nickel zinc batteries is combined with an emergency power supply system. According to the embodiment, it is possible to provide a suitable emergency power supply system capable of realizing sufficient discharge power supply from a storage battery to a load device during a power failure. Although the trickle charge power supply system of the embodiment is preferably applied to an emergency power supply system, it can also be applied to other uses. The trickle charge power supply system of the embodiment can be applied to ground storage facilities such as a hybrid system and an uninterruptible power supply (UPS).

The present invention has been specifically described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Power supply for charge, 2 ... Load, 3 ... Storage battery part, 4 ... Power failure detection relay part, 5 ... Switch, 6 ... Terminal part, 30 ... Storage battery, 71 ... AC electric wire, 72, 73, 74 ... DC electric wire, 81 …Control signal.

Claims

A storage battery unit including a nickel zinc battery as a storage battery;
A commercial power system, a load, and a charging power source connected to the storage battery unit;
With
In a normal state, the storage battery of the storage battery unit is not connected to the load, and trickle charging is performed on the storage battery of the storage battery unit with DC power from the charging power source based on AC power of the commercial power system. ,
At the time of a power failure when the AC power of the commercial power system is interrupted, the storage battery of the storage battery unit is connected to the load, and DC power by discharge is supplied from the storage battery of the storage battery unit to the load.
When the fully charged state is 100%, the storage battery is operated in the SOC range of 95% or more and 100% or less,
The trickle charge voltage of the trickle charge is a constant voltage within a range of 1.82V to 1.86V, and the maximum current of the trickle charge current is 1C.
Trickle charging power system.
In the trickle charge power supply system according to claim 1,
The nickel zinc battery is
A positive electrode using nickel hydroxide or nickel oxide as a positive electrode active material;
A negative electrode using zinc oxide or zinc as a negative electrode active material;
An electrolyte comprising an alkaline aqueous solution;
Having
Trickle charging power system.
In the trickle charge power supply system according to claim 1,
The storage battery unit has a plurality of nickel zinc batteries connected in series as the nickel zinc battery,
Trickle charging power system.
In the trickle charge power supply system according to claim 1,
The storage battery unit has a plurality of nickel zinc batteries connected in parallel as the nickel zinc battery,
Trickle charging power system.