JP2003017135A - Midnight power shifting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To earn a profit from the difference of electricity rate between night time and daytime by utilizing an inverter of a solar generator system which is not used while the sun is not shining, and to ensure the collection of investment by prolonging the life of a secondary battery. SOLUTION: A peak shift is realized by adding a charging device, a secondary battery, and a cooling device to an existing solar generation system, here, an existing inverter is utilized. The wave form of charging and discharging current is turned into a software, and a temperature management of the secondary battery electrode is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION As the proportion of nuclear power generation increases, the power output adjustment capacity of nuclear power generation becomes low, resulting in an excessive amount of electric power in the midnight hours. . Thermal power generation emits a large amount of carbon dioxide and is considered to be one of the main causes of global warming. Therefore, there is a strong need for peak shift in which electric power is transferred to the living time zone by using electric power in the midnight time zone.

An hourly electricity rate system has been introduced, and efforts are being made to reduce late-night electricity and spread heat storage services and electric water heaters. It is a device that charges a secondary battery with electric power in the midnight time period, converts it into commercial power with an inverter in the living time period, and sells it. It can be economically realized by diverting the inverter for solar power generation, which is becoming popular as a clean energy in general households. By operating this device, the output of thermal power generation can be narrowed down, reducing CO2 emissions and contributing to the prevention of global warming.

[0003]

2. Description of the Related Art A conventional photovoltaic power generation system has a configuration shown in FIG. 3 and does not function at all until the sun rises again and rises again as shown in the graph of FIG. Is not working. Moreover, the life of the secondary battery 8 is short and insufficient. As a similar device, JP-A-6-26645 is used.
There are 7,458, etc., but the purpose is different.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As shown in FIGS.
By charging the secondary battery 8 for 10 hours from 22:00 to 8:00 on the next day, discharging it in the living time when the sun is not shining, converting it into commercial power by the inverter 5, and transmitting it to the distribution system, Make it possible to contribute to load leveling of the power system.

The important thing to surely recover the investment of the charger 1 of the secondary battery 8 and the secondary battery and to make a profit is to prolong the life of the secondary battery due to the frequent deep charging and discharging of the secondary battery. To keep. It is considered that the life of the secondary battery 8 is caused by the temperature change and rate of change of the battery electrode plate due to charging and discharging, and the active material falling off due to expansion and contraction of the electrode plate due to temperature changes of the environment such as season and time. The problem is to prevent this.

In solving the above problems, the inverter 5 can be realized at a lower cost by utilizing an existing product for solar power generation.

[0007]

As shown in FIG. 1, a charger 1, a secondary battery 8 and a cooling device FIG. 7 are added to an existing photovoltaic power generation system to charge the secondary battery 8 with a cheap midnight power. To do. During the time when the sun is tilted, the inverter 5 for photovoltaic power generation is used to discharge electricity and sell the electricity. That is, the peak shift is realized.

FIG. 6 is a graph showing changes in the conventional charging / discharging current and changes in the temperature of the electrode plate. Since the rising and falling of the current are rapid, a large thermal stress is generated in the electrode plate at the portions A and B, and this repetition damages the electrode plate and shortens the life.

As a countermeasure against this, the rise and fall of the charging / discharging current of the secondary battery 8 is made to have a gradient to reduce the change and rate of change of the temperature of the electrode plate.

The secondary battery 8 is water-cooled and the following temperature control is performed to reduce the temperature change of the electrode plate and extend the life.

As shown in FIG. 7, the battery case of the secondary battery 8 is a water tank 12.
It exchanges heat with the surrounding cooling water. The cooling water tank 11 has two suction ports 11A and 11B of the cooling water circulation pump 9. When cooling, the cooling water having a low water temperature in the lower portion 11B is used, and when heating, the cooling water having a high water temperature in the upper portion 11A is used. Use water. This switching is performed by the solenoid valve 10.

Since the cooling water in the cooling water tank is used as the heat source for heating and cooling, it is not particularly necessary. As shown in FIG. 7, the return of the cooling water is discharged to the upper part 11A of the cooling water tank 11, and the return at the time of heating is discharged to the lower part 11B. The structure is such that cold water at the top separates at the bottom.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 5 is a graph showing a change in charge / discharge current and a change in temperature of an electrode plate when temperature control and softening for giving rise and fall of charge / discharge current are performed.

Normally, when the secondary battery is warmed to a temperature intermediate between the ambient temperature and the maximum temperature shown in FIG. 6 to start charging,
Switch 13A is closed, switch 13B is opened, and IGBT 14A
Control the charging current with. When starting discharge, switch 13
B is closed and the switch 13A is opened to control the discharge current by the IGBT or the like 14B. The above control is performed by the control device 2.

[0015]

EXAMPLE FIG. 1 shows. Secondary battery water tank 12 and cooling water tank 1
If the position 1 and other factors are taken into consideration, the power required for the cooling water circulation pump is small and the amount of water is small, which is not a problem. The control device 2 has a calendar and a clock therein, holds data of changes in sunrise and sunset depending on the season, and outputs signals at the start and end times of charging and discharging of the charger 1 and the solenoid valve 10. It does not compete with the output of solar power generation.
In this way, the system becomes completely trouble free.

[0016]

EFFECTS OF THE INVENTION On the power supply side, load leveling is promoted, which facilitates system operation, which is desirable, and since it is a distributed facility, no special reinforcement of the distribution system is required. .

Since the installer of the late-night power shift device can buy the cheap late-night power and sell it at the normal power rate, the difference becomes a profit. By controlling the temperature of the rechargeable battery, the life of the rechargeable battery can be maintained for a long time, so that the investment can be reliably recovered. The peak shift is promoted and it can contribute to the prevention of global warming.

[Brief description of drawings]

FIG. 1 Overall configuration of a solar power generation system with a midnight power shift function (Example 1)

[Fig. 2] Operating hours of a solar power generation system with a midnight power shift function

[Fig. 3] Configuration of a conventional photovoltaic power generation system

[Fig. 4] Operating hours of conventional solar power generation system

[Fig. 5] Graph of temperature-controlled soft change of charge / discharge current and temperature change of electrode plate

FIG. 6 is a graph of conventional charge / discharge current and temperature change of the electrode plate

FIG. 7: Cooling device

[Explanation of symbols]

1 charger 2 control device 3 distribution board 4 Electricity meter for trading power 5 inverters 6 generated electricity meter 7 solar cell module 8 secondary battery 9 Cooling water circulation pump 10 solenoid valve 11 cooling water tank 11A Upper suction port and discharge port 11B Lower suction port and discharge port 12 secondary battery water tank Switch for charging 13A Switch for 13B discharge 14A charging IGBT etc. 14B discharge IGBT etc. 15 solar power output 16 charging hours 17 discharge hours 18 fever 19 heating 20 cooling A, B sudden temperature change

Claims (4)

[Claims] 1. A charging / discharging control system in which a rising and a falling of a charging / discharging current have a gradient in order to extend the charging / discharging cycle life of a secondary battery. 2. The temperature change and temperature change rate of the electrode are obtained by cooling the battery case with water, cooling during charging / discharging, and always heating to extend the charging / discharging cycle life of the secondary battery. Cooling method with smaller size. 3. A peak shift device in which a charger, a secondary battery and a cooling device are added to an existing household solar power generation system. 4. A heating and cooling device for a secondary battery which does not require a cold heat source from the outside.