KR20180120500A - Energy storage system with solar cell - Google Patents

Abstract

Disclosed is a solar connected type energy storage system. The solar connected type energy storage system of the present invention comprises: a storage battery; a solar cell; a charger receiving electric energy from a common distribution network as grid input voltage to supply to a load, or converting the electric energy into direct current to store in the storage battery; an inverter converting the electric energy stored in the storage battery into alternating current to supply to the load; and a charging/discharging control part controlling the solar cell and the charger so as to store the electric energy in the storage battery according to a preset environment, and controlling the inverter so as to supply the electric energy stored in the storage battery to the load. Therefore, the present invention can supply a power in evening and night time zones in an area in which a power situation is poor or power supply is impossible.

Description

[0001] ENERGY STORAGE SYSTEM WITH SOLAR CELL [0002]

The present invention relates to an energy storage device, and more particularly, to an energy storage device that not only stores and supplies energy using sunlight but also adds a power supply using a power distribution scheme The present invention relates to a solar-energy-linked energy storage system capable of efficiently supplying electric power by using sunlight and an outlook.

Energy storage system (ESS: Energystoragesystem), which is the core of smart grid recently, is a system for storing energy, and various devices are being developed. Typical ones are stored in a battery through a charger at night, The electric power demand will discharge at a high time. This is commonly referred to as a grid-connected energy storage system.

In addition, various types of energy utilization schemes using solar power, solar power, geothermal energy, etc., which are eco-friendly energy sources, are stored in a storage device and used in parallel with electric power supplied in a commercial manner are disclosed in Korean Patent Registration No. 10-1216704 (Method of connecting grid power of stand-alone solar street lamp and its operation method), Korean Patent Laid-Open Publication No. 2012-0100157 (load power supply system and method using energy storage device)

The power management system that utilizes the renewable energy as described above has the problem of inefficiently utilizing the generated electric power due to its nature due to the characteristics thereof and the electric power should be used at the expensive electric power fee if necessary, And it does not contribute to the recovery of the investment cost.

KR Patent Registration No. 10-1216704 (2012.12.21)

In order to solve these problems, the present invention is directed to a solar-energy-type energy storage system for reducing electric power charges through ESS in a home or small-scale enterprise, and enabling power to be used at evening and night time in an area where the power condition is poor, System.

In addition, the present invention provides a system configuration and operation method for a power storage device used by a home or small-sized company, and a photovoltaic energy storage system capable of being connected to a solar power generation device and being applicable to a stand- To provide another purpose.

In order to solve the above-mentioned problems, the solar energy-linked energy storage system of the present invention for solving the above-mentioned problems comprises a storage battery for storing electric energy, a solar battery for converting the light energy of sunlight into electric energy and storing it in the storage battery, A charger for supplying electric energy to the load as a grid input voltage, converting the electric energy into a DC voltage and storing the electric energy in the battery, an inverter for converting electric energy stored in the battery into an AC voltage and supplying the AC voltage to a load, And a charging / discharging control unit for controlling the solar cell and the charger to be stored in the storage battery, and controlling the inverter to supply electric energy stored in the storage battery to the load.

The charging / discharging control unit starts charging when the charging start time arrives, when the battery voltage is below the set voltage, when the charging start temperature is below the set temperature, or when the grid power source is being charged. If no voltage is detected, the UPS proceeds to uninterruptible power supply (UPS) discharge mode and the discharging current lasts for a certain period of time at a voltage lower than the battery voltage set at a current higher than the set battery current, And stops discharging when the voltage is less than the set battery voltage and lasts for a predetermined time or more.

In addition, when the grid input voltage flows into the UPS discharge mode and the set discharge time has arrived, or when the grid input voltage is not sensed, and when the grid input voltage flows into the discharge set time during the discharge mode, the system goes to the economic discharge mode and proceeds to the UPS discharge mode when the grid input voltage is inputted and is switched to the grid off state at the discharge set time.

When the load power is larger than the generated power of the solar cell, the charge / discharge control unit discharges the insufficient power to the battery to supply power to the load. When the load power is smaller than the generated power of the solar cell, As shown in Fig.

Therefore, according to the solar-energy-linked energy storage system of the present invention, it is possible to supply necessary power in evening and night time zones in a region where the power condition is poor or the power supply is impossible.

Further, according to the photovoltaic energy storage system of the present invention, it is possible to supply emergency power when the power supply is stopped due to a power failure even in the grid connection operation, and the user can reduce the electric power charge There is an effect that can be achieved.

According to the photovoltaic energy storage system of the present invention, the amount of solar power generated between the power unit price supplied from the power system, the peak time, the diurnal state of the next day, By determining the transmission, grid power and parallel operation, it is possible to operate the power facility under the most economical cost conditions, thereby saving energy and reducing electric power charges.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main configuration diagram of a solar energy-linked energy storage system according to an embodiment of the present invention;
FIG. 2 is a flowchart illustrating a charging process of the energy storage system of the present invention.
FIG. 3 is a flowchart for explaining a charge stopping process of the energy storage system of the present invention.
FIG. 4 is a flowchart illustrating a UPS discharge mode of the energy storage system of the present invention. FIG.
FIG. 5 is a flowchart for explaining the energy discharge mode of the energy storage system of the present invention,
And
FIG. 6 is a flowchart for explaining the EC mode of the energy storage system of the present invention.

It is to be understood that the words or words used in the present specification and claims are not to be construed in a conventional or dictionary sense and that the inventor can properly define the concept of a term in order to describe its invention in the best possible way And should be construed in light of the meanings and concepts consistent with the technical idea of the present invention.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. It should be noted that the terms such as " part, "" module, " .

It is to be understood that the term "and / or" throughout the specification includes all possible combinations from one or more related items. For example, the meaning of "first item, second item and / or third item" may be presented from two or more of the first, second or third items as well as the first, second or third item It means a combination of all the items that can be.

Identification codes (e.g., a, b, c, ...) in each step throughout the specification are used for convenience of description, and the identification codes do not limit the order of each step, Unless the context clearly states a particular order, it may take place differently from the stated order. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

The terms used in the present invention are defined as follows.

"Economical discharge mode" means discharging at the time desired by the user when the system is connected.

"UPS Discharge Mode" means discharge when system is not connected.

Hereinafter, a photovoltaic energy storage system according to an embodiment of the present invention will be described with reference to the drawings.

1 is a block diagram of a solar energy-linked energy storage system according to an embodiment of the present invention. As shown in FIG. 1, the solar energy-linked energy storage system according to an embodiment of the present invention includes a storage battery An inverter 160 for converting the electric energy stored in the storage battery 150 into AC and supplying the load to the load, and a solar cell 140. The solar cell 140 includes a solar cell 140, a charger 120 that stores the solar cell 140, And a charge / discharge controller 110 for controlling the inverter 160 by controlling the charger 120, storing the chargeable battery 120 in the battery 150, and the like.

The solar cell 140, which is also referred to as a photocell, is a device capable of converting solar energy into electrical energy. When a semiconductor junction region having a PN junction surface is irradiated with light having an energy greater than the forbidden band width, electrons and holes are generated, An electron is an N-type semiconductor, and a hole is a P-type semiconductor, and an electromotive force is generated.

That is, the solar cell 140 is operated to convert the light energy of the sunlight into electric energy and store it in the battery 150.

STORAGE BATTERY 150 is a type of battery in which two electrodes (positive and negative electrodes) are immersed in an electrolyte to convert the active energy of each electrode and the chemical energy of the electrolyte into electrical energy, To generate electric energy in the external circuit connecting the anode and the cathode.

The charger 120 is operative to receive electrical energy from a common distribution line (AC IN) 130 as a grid input voltage, convert it into a DC current, and store it in the battery 150.

The relay 170 is controlled by the charge / discharge control unit 110 so that the electric energy input from the common distribution line (AC IN) 130 is bypassed and directly supplied to the load 180, The power supply of the inverter 160 that outputs the power supplied from the inverter 180 is supplied to the load 180.

Discharge control unit 110 controls the solar cell 140 and the charger 120 to store electric energy in the battery 150 according to a predetermined environment and controls the charging and discharging of the battery 150 by using the electric energy stored in the battery 150 to the load 180 Controls the inverter 160 and controls the relay 170 so as to supply it.

The charging / discharging control unit 110 of the present invention having the above-described configuration supplies the grid input power by bypass to the load 180 during normal operation, and the charging power of the storage battery 150 is supplied to the inverter 160, To be supplied to the load 180. [0050]

In addition, the charge / discharge control unit 110 has a timer function therein, and the charge time can be adjusted by user setting.

That is, the battery 150 can be controlled to charge and discharge in the night time zone or in the required time zone or when the condition is established, and the battery 150 can be charged with the output voltage of the solar cell 140 using the overcharge control function.

The energy storage system having the above-described configuration can shorten the battery usage time by the bypass function, and can maintain the backup time (Back-up time) even when using the constant load with the overcharge prevention function through the solar light charge control.

Hereinafter, an operation algorithm of the energy storage system of the present invention will be described with reference to the drawings.

FIG. 2 is a flow chart for explaining the charging process of the energy storage system according to the present invention. In the present invention, the voltage (Batt V) of the battery 150 is defined as 12 V and the current (Batt I) (S110).

Discharge control unit 110 determines that the set charging time has come (S111), the battery voltage (Batt V) has dropped below "1.04 * Batt V" after the previous charging mode (S112) If the temperature is lower than 40 (S113) and the grid power source AC IN is introduced (S114), the battery 150 is charged (S115).

In step S115, the charging is stopped when the set condition is satisfied so that the overcharge can be protected.

3, the charge / discharge control unit 110 determines that the set charge stop time has come (S121) ), The battery voltage (Batt V) becomes equal to or greater than "1.23 * Batt V" (S122) after the previous charging mode, the temperature of the battery is maintained at 50 for 3 minutes or more (S123) (S124). If the rate of decrease of "Batt V" exceeds 0.01 x (Batt V / 12) (S125), charging is stopped (S126).

As described above, when the battery 150 is charged, the discharge progresses when the grid input voltage is not sensed. In the present invention, the discharge is referred to as a UPS discharge mode.

This is because when the power of the system is shut off due to a power failure, the power can be supplied from the battery through the relay interception of the system line and the relay on control of the inverter line, and the function of the uninterruptible power supply (UPS) to be.

In the meantime, according to the present invention, even if the system is connected, the discharging function can be performed according to the set condition, which is called an economic discharge mode.

FIG. 4 is a flowchart illustrating a UPS discharge mode of the energy storage system of the present invention. When the grid input voltage is not sensed (S 130), the charge / discharge control unit 110 proceeds to UPS discharge mode (S 131).

In the UPS discharge mode, the relay 170 is controlled so that the voltage charged in the battery 150 is supplied to the load 180 via the inverter 160.

When the following condition is satisfied during the UPS discharge mode in step S131, the charge / discharge control unit 110 controls the relay 170 to stop the discharge.

That is, when the discharging current exceeds "0.5xBatt I" and continues for less than "0.83xBatt V" for one minute (S132), the discharging current is less than "0.92xBatt V" (S133), when the discharge current is maintained at 0.96xBatt V or less for 1 minute or less (S134) while the discharge current is lower than "0.2xBatt I ", and when the battery temperature is 45 or more and lasts more than 5 minutes (S135) stops discharging (S136).

The following describes the economic mode during the discharge mode.

FIG. 5 is a flowchart for explaining the energy discharge mode of the energy storage system of the present invention. In the UPS discharge mode, when a grid input voltage flows, a discharge set time comes, or a grid input voltage is not detected, In the case where the grid voltage flows into the in-progress discharge setting time (S143), the mode enters the electric discharge mode.

First, the charge / discharge control unit 110 determines whether the grid input voltage is sensed. If no voltage is sensed, the UPS discharge mode is first performed (S140 to S141).

In step S141, when the UPS discharging mode is proceeded, if the following condition is satisfied, the mode enters the economic discharge mode.

That is, when the grid input voltage flows into the UPS discharge mode and the discharge set time arrives (S142), when the grid voltage enters the discharge set time during the discharge mode in the state where the grid input voltage is not detected S143), the mode enters the economic discharge mode (S146).

Or when the grid voltage is turned off at the discharge set time with the grid input voltage flowing (S144), the UPS goes to the discharge mode (S145).

Finally, FIG. 6 is a flowchart for explaining the EC mode of the energy storage system of the present invention.

As shown in the drawing, when the discharge current is greater than or equal to "0.96xBatt V" for one minute or more (S161) while the discharge current exceeds "0.5xBatt I" while the economy discharge mode is in progress (S160) When discharging current exceeds "0.2xBatt I" and lasts for less than "1.00xBatt V" for more than one minute (S162), discharging current is less than "0.2xBatt I" and less than "1.04xBatt V" (S163), and when the battery temperature is 45 or more (S164) for more than 5 minutes, the discharge is stopped (S165).

The charge / discharge control unit 110 proceeds to the UPS discharge mode when the grid input voltage is switched to the grid off state at the discharge set time, and maintains the discharge stop mode when the discharge set time is reached after the UPS discharge stop mode.

As described above, according to the photovoltaic energy storage system of the present invention, in the grid-connected operation, the constant load supplies power to the lower stage through the by-pass of the grid power, The battery can be charged with electric power through the discharge control unit, and the electric power can be also charged to the battery through the charger and the charge / discharge control unit.

The charging / discharging control unit controls the charging of the battery according to the charging algorithm, and performs on / off of the charger, relay on / off of the inverter on / off, and by-pass.

The charging and discharging control unit can charge the battery through the charging algorithm of the battery and the solar MPPT function.

In addition, the operator can use the inverter from the battery in place of the grid power at the required time (the relay can be controlled by turning on / off the inverter and the bypass).

In addition, when the grid power is cut off due to a power failure or the like, the battery charging and discharging of the relays of the inverter line and the inverter line, On control can be used to supply power from the battery, which can also be used as a UPS function.

On the other hand, in the stand-alone operation, the functions of the main parts are the same as those of the grid-connected functions, and only the grid power and the charger function are eliminated. In the evening, solar power is charged to the storage battery, So that power can be supplied to the load.

If necessary, the power can be supplied to the load through the battery even during the daytime solar power generation, and can be operated according to the following conditions.

That is, in the case of "load power> photovoltaic power generation", power is supplied to the load by discharging the insufficient power to the battery.

In the case of "load power <photovoltaic power generation", the remaining solar photovoltaic power is to be charged into the storage battery.

This is the same as in the case of grid linkage operation and can be operated through functions.

And charge / discharge control block is overheated for battery and system safety. It is also possible to perform safety functions such as overcurrent, battery voltage cutoff, cooling fan operation, and the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.

110: charge / discharge control unit 120: charger
140: Solar cell 150: Storage battery
160: inverter 170: relay
180: Load

Claims (6)

A battery storing electrical energy;
A solar cell for converting light energy of sunlight into electrical energy and storing the electrical energy in the battery;
A charger that receives electric energy from a common distribution line as a grid input voltage and supplies the load to a load or converts the electric energy into a direct current and stores the electric energy in the accumulator;
An inverter for converting the electric energy stored in the storage battery into an alternating current and supplying the alternating current to the load; And
A charge / discharge control unit for controlling the solar cell and the charger to store electric energy in the battery according to a predetermined environment, and controlling the inverter to supply electric energy stored in the battery to a load;
And an energy storage system.
The method according to claim 1,
The charge / discharge control unit
Wherein the charging is started when the charging start time arrives, the battery voltage is lower than the set voltage, the charging start temperature is lower than the set temperature, or the grid power is supplied.
The method according to claim 1,
The charge / discharge control unit
If the grid input voltage is not detected, the UPS proceeds to an uninterruptible power supply (UPS) discharge mode and the discharge current is maintained at a voltage lower than the battery voltage set at a current higher than the set battery current for a certain period of time, The solar energy-linked energy storage system stops discharging when the voltage is less than the battery voltage set by the current for a certain period of time. The method according to claim 1,
The charge / discharge control unit
In the case where the set discharge time comes when the grid input voltage flows in the UPS discharge mode, or when the grid input voltage flows into the discharge set time during the discharge mode in the state where the grid input voltage is not detected, Ongoing solar photovoltaic energy storage system.
The method of claim 4,
The charge / discharge control unit
A solar energy-linked energy storage system that goes to a UPS discharge mode when a grid input voltage is introduced and the grid is turned off at a discharge setup time.
The method according to claim 1,
The charge / discharge control unit
When the load power is larger than the generated power of the solar cell, the battery is supplied with power by discharging the insufficient power to the load, and when the load power is smaller than the generated power of the solar cell, Linked energy storage system.

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