KR20080023989A - Circuit for equaling of voltage and electric energy storage device having the same - Google Patents

Abstract

A voltage equalizing circuit and an electric energy storage device having the same are provided to improve charge performance of the electric energy storage device effectively by connecting the voltage equalizing circuit having a light emitting device and a photoconductive cell to both ends of each unit cell. A voltage equalizing circuit(120) includes a light emitting unit and a voltage equalizing unit. The light emitting unit is connected to both ends of a unit cell(C1~Cn) in parallel to emit light by voltage applied to the both ends of the unit cell. The voltage equalizing unit is connected to the both ends of the unit cell in parallel, receives the light emitted from the light emitting unit, increases or decreases a resistance value according to intensity of the received light, and equalizes the voltage applied to the both ends of the unit cell according to increase or decrease of the resistance value.

Description

Voltage equalization circuit and electric energy storage device having the same {Circuit for equaling of voltage and Electric energy storage device having the same}

The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the detailed description of the present invention, serve to further understand the technical spirit of the present invention. It should not be construed as limited to.

1 is a circuit diagram illustrating a voltage equalization circuit electrically connected to each unit cell of an electric energy storage device according to the prior art.

2 is a circuit diagram illustrating a voltage equalization circuit electrically connected to each unit cell of an electrical energy storage device according to a preferred embodiment of the present invention.

<Description of Major Reference Marks in Drawing>

100 ... Electrical energy storage device 120 ... Voltage equalization circuit

121 ... Packaging Case C1, Cn ... First and Nth Unit Cell

V1, Vn ... first and Nth charging voltages R1 ... first resistance element

L ... light emitting element R2 ... second resistance element

P ... optical conductive element

The present invention relates to a voltage equalization circuit and an electric energy storage device including the same, and more particularly, to a voltage equalization circuit for improving the charging and discharging performance by uniformizing the voltage between unit cells constituting the electric energy storage device. It relates to an electrical energy storage device.

In general, a capacitor is a device for obtaining an electric capacity, and is used as a storage battery and a secondary battery as a means for storing electrical energy.

Capacitors have specifications such as capacity, withstand voltage, frequency characteristics, leakage current, and internal resistance depending on the material of the dielectric used to increase their capacity, and are used as electrolytic capacitors, tantalum capacitors, ceramic capacitors, and electric double layer capacitors. Are classified.

In addition, capacitors are used in a variety of applications, ranging from small-capacitor capacitors used in ultra-light-weight compact chips to medium and large-capacitor capacitors used in power systems, depending on their capacity and use.

Recently, medium and large capacity capacitors have been diversified according to specifications due to high capacity and high output, and ultracapacitors, which are a kind of electric double layer capacitors, have very long charge / discharge lifetime, high charge / discharge efficiency, and temperature. Good performance variation against change, relatively small resistance and fast charging compared to secondary batteries, making industrial power supplies such as electric vehicles, hydrogen fuel cell vehicles, solar power supplies and uninterruptible power supplies (UPS) Increasing use in devices and the like.

Usually, equipment using ultracapacitors as industrial power supplies requires high voltages of tens to thousands of volts, so a few volts of ultracapacitors are connected in series to be used as electrical energy storage devices. A voltage deviation occurs between each unit cell, that is, due to a capacitance variation, an initial voltage variation, a leakage current variation, and a capacity reduction rate variation with use time between each unit cell. This voltage deviation acts as a cause of failure of the electrical energy storage device, and acts as a factor to shorten the life of the electrical energy storage device.

A technique for improving the charging performance of the electrical energy storage device by solving the defects caused by the above-described voltage deviation has been proposed. In Japanese Patent Laid-Open No. 2004-222438, as shown in FIG. A technique is disclosed in which a balancing circuit composed of a zener diode (Z) and a resistor (R) is connected in parallel to each of the electric double layer capacitors (C) so that the charging voltage (V) of each of the double layer capacitors (C) is equalized. US 5,710,504 discloses a technique for equalizing the voltage of a unit cell by transferring energy from a high voltage unit cell to a low voltage unit cell using a switch and a capacitor.

However, the technique according to 2004-222438 can control the voltage of the electric double layer capacitor overcharged than the designed voltage using a zener diode, but cannot control the voltage of the electric double layer capacitor undercharged than the designed voltage. In addition, there is a problem in that the characteristic variation according to temperature is severe, and it is not effective in the device requiring partial charging and discharging.

In addition, the technique according to No. 5,710,504 is excellent in voltage equalization accuracy between unit cells, but there is a problem that the price is expensive due to the complex structure.

The present invention has been made in view of the above problems, and provides a voltage equalization circuit that simplifies the circuit structure and effectively suppresses voltage unbalance due to high and low charges between unit cells, and an electrical energy storage device having the same. The purpose is.

A voltage equalization circuit according to the present invention for achieving the above object is electrically connected to each of a plurality of unit cells connected in series to achieve a voltage equalization of each of the unit cells, both ends of the unit cells A light emitting unit connected in parallel to both ends of the unit cell so as to emit light by a voltage applied to the unit cell; And receiving light emitted from the light emitting unit, increasing or decreasing a resistance value according to the intensity of the received light, and equalizing a voltage applied to both ends of the unit cell according to the increase or decrease of the resistance value. And a voltage equalizer connected in parallel to both ends thereof.

In the present invention, the light emitting portion, the first resistance element; And a light emitting device connected in series with the first resistor to emit light in proportion to the intensity of the voltage.

Preferably, the light emitting elements are connected in parallel in the forward direction with respect to both ends of the unit cell.

According to the present invention, the voltage equalizing unit includes: a second resistor element; And an optically conductive element connected in series with the second resistance element and having a resistance value that increases or decreases with light intensity.

Preferably, the resistance value decreases as the light intensity increases, and increases as the light intensity decreases.

More preferably, the light emitting element and the photoconductive element are provided in a packaging case that blocks external light.

According to the present invention, the unit cell is an ultracapacitor provided in an electrical energy storage device.

According to another aspect of the present invention, an electric energy storage device used as an industrial power supply, comprising: a plurality of unit cells connected in series; A light emitting unit connected in parallel to both ends of each of the unit cells so as to emit light by a voltage applied to both ends of each of the unit cells; And receiving the light emitted from the light emitting unit, increasing or decreasing the resistance value according to the strength and weakness of the received light, and equalizing the voltage applied to each end of each unit cell according to the increase or decrease of the resistance value. Provides an electrical energy storage device comprising; a voltage equalizer connected in parallel to both ends of each cell.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in this specification and claims should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, which can be replaced at the time of the present application It should be understood that there may be various equivalents and variations.

The electrical energy storage device according to the present invention includes a plurality of unit cells connected in series to charge and discharge desired electric power. The unit cells are open at one side to accommodate the electrode assembly together with an electrolyte. And a terminal plate sealing the inside of the housing, and an external connection terminal connecting the electrode assembly and an external circuit.

In the exemplary embodiment of the present invention, the unit cell has been described based on an ultracapacitor, but is not limited thereto. For example, an electric double layer capacitor or a secondary battery including an ultracapacitor may be applied as a unit cell according to the purpose of use and the capacitance of the electric energy storage device.

In addition, the electric energy storage device configured by connecting the unit cells in series includes a voltage equalization circuit, and in FIG. 2, electrical energy including a voltage equalization circuit electrically connected to each of the unit cells according to an exemplary embodiment of the present invention. A circuit diagram of the storage device is shown.

As shown in FIG. 2, the electrical energy storage device 100 is provided at both ends of the first to Nth unit cells C1 to Cn and the first to Nth unit cells C1 to Cn connected in series. And a voltage equalization circuit 120 connected in parallel.

In an embodiment of the present invention, each of the first to Nth unit cells C1 to Cn has a structure in which an opening is formed at one side to accommodate the electrode assembly together with the electrolyte, although not shown in the drawing. And a pair of external connections provided on the terminal plate to seal the opening to block the inside and the outside of the housing, and to be electrically connected to the positive and negative lead wires of the electrode assembly to protrude out of the housing. It includes a terminal.

In addition, the electrode assembly is a stacked or wound assembly, which includes a positive electrode and a negative electrode body having a polarizable electrode formed on a surface of a current collector plate, a positive electrode and a negative electrode lead wire connected to the positive electrode and a negative electrode body, and the positive electrode and It consists of a separator interposed between the cathode electrode bodies, and serves to substantially charge and discharge electricity.

In addition, the positive and negative lead wires are electrically connected to a pair of external connection terminals, and the external connection terminals are electrically connected in parallel with the voltage equalization circuit 120.

The voltage equalization circuit 120 includes a light emitting part and a voltage equalizing part connected in parallel to both ends of each of the first to Nth unit cells C1 to Cn, that is, to external connection terminals.

The light emitting unit includes a first resistive element R1 and a light emitting element L connected in series with the first resistive element R1. The light emitting element L includes first to Nth unit cells C1 to Cn. Light is emitted by the voltages V1 to Vn applied to both ends thereof. At this time, the intensity of the light is proportional to the intensity of the voltage (V1 to Vn). For example, the light emitting device L emits weak light when the intensity of the voltages V1 to Vn is small, and emits strong light when the intensity of the voltages V1 to Vn is large.

In this case, the light emitting device L is preferably a light emitting diode LED, but is not limited thereto. The light emitting device L may be connected in parallel in the forward direction to both ends of each of the first to Nth unit cells C1 to Cn. That is, the light emitting element L is connected in a direction coinciding with the current path.

The voltage equalizer connected in parallel with the light emitting part includes a second resistance element R2 and a photoconductive cell P connected in series with the second resistance element R2. Is linked to the light emitting element L of the light emitting unit. That is, it receives the light emitted from the light emitting element (L), and has a resistance value that varies according to the intensity of the light. At this time, the resistance value is inversely proportional to the light intensity. For example, the resistance value of the photoconductive element P decreases as the light intensity increases, and increases as the light intensity decreases.

At this time, when the resistance value increases or decreases due to the light intensity, the amount of current flowing through each of the first to Nth unit cells C1 to Cn increases and decreases, and the first to Nth unit cells C1 increases or decreases according to the amount of current. To Cn), each of the charging voltages V1 to Vn increases or decreases.

In the embodiment of the present invention, the light emitting element (L) and the photoconductive element (P) is interlocked with the operation of the light, the operation error occurs when the light is affected by the external light, the light emitting element (L) ) And the photoconductive element P are provided in the packaging case 121 to be blocked from external light.

Referring back to FIG. 2, the operation of the voltage equalization circuit including the light emitting unit and the voltage equalizing unit to contribute to voltage equalization of each unit cell constituting the electric energy storage device will be described below. In this case, the first and the N-th unit cells constituting the electrical energy storage device, there is a voltage deviation, for better understanding according to an embodiment of the present invention, the voltage of the first unit cell is higher than the reference voltage, It is assumed that the voltage of the N unit cell is lower than the reference voltage.

As shown in FIG. 2, when a voltage is applied to the electrical energy storage device 100, the first to Nth charging voltages are respectively applied to the first to Nth unit cells C1 to Cn connected in series with the electrical energy storage device. (V1 to Vn) are applied.

In this case, a voltage applied to the light emitting units connected in parallel to both ends of the first unit cell C1 is applied with a voltage greater than a reference value, and more current than the reference value flows to the light emitting element L of the light emitting unit due to the voltage. The light emitting element L emits light stronger than the reference value toward the photoconductive element P side of the voltage equalizing portion.

As a result, the photoconductive element P has a lower resistance value than the reference value, and the amount of current flowing into the voltage equalizing part is greater than the reference value by the resistance value, so that the first charging voltage V1 higher than the initial reference voltage. It becomes equal to this reference value.

On the other hand, a voltage applied to the light emitting units connected in parallel to both ends of the Nth unit cell Cn is applied with a voltage smaller than a reference value, and a current smaller than the reference value flows to the light emitting element L of the light emitting unit due to the voltage. The light emitting element L emits light weaker than the reference value toward the photoconductive element P of the voltage equalizing portion.

Accordingly, the photoconductive element P has a larger resistance value than the reference value, and the amount of current flowing into the voltage equalizing part is smaller than the reference value by the resistance value, thereby lowering the Nth charging voltage Vn lower than the initial reference voltage. It becomes equal to this reference value.

As described above, each of the unit cells (C1 to Cn) of the electrical energy storage device 100 is different from the first to Nth charging voltage (V1 to Vn) due to the characteristic difference including the capacity deviation at the beginning of charging, Voltage equalization is performed by the voltage equalization circuit 120 provided in each of the unit cells C1 to Cn, and it can be seen that the voltage deviation between the unit cells C1 to Cn is eliminated.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

As described above, according to the present invention, the voltage equalization circuit including the light emitting element and the photoconductive element is connected in parallel to both ends of each unit cell, thereby eliminating voltage imbalance due to high and low charges between the unit cells, and storing electrical energy. The charging performance of the device can be effectively improved.

In addition, a simple circuit configuration can contribute to a reduction in manufacturing cost and productivity.

Claims (14)

In a circuit electrically connected to each of a plurality of unit cells connected in series to achieve voltage equalization of each of the unit cells, A light emitting unit connected in parallel to both ends of the unit cell so as to emit light by a voltage applied to both ends of the unit cell; And Receiving light emitted from the light emitting unit, the resistance value increases or decreases according to the intensity of the received light, and the voltage applied across the unit cell according to the increase or decrease of the resistance value, both ends of the unit cell, And a voltage equalizer connected in parallel to the voltage equalization circuit. The method of claim 1, wherein the light emitting unit, A first resistance element; And And a light emitting element connected in series with the first resistance element and emitting light in proportion to the intensity of the voltage. The method of claim 2, And the light emitting elements are connected in parallel in the forward direction with respect to both ends of the unit cell. The method of claim 2, wherein the voltage equalizer, A second resistance element; And And a photoconductive element connected in series with the second resistance element, the photoconductive element having a resistance value that increases or decreases according to the intensity of light. The method of claim 4, wherein And the resistance value decreases as the light intensity increases, and as the light intensity decreases, the voltage equalization circuit increases. The method of claim 4, wherein And the light emitting device and the photoconductive device are provided in a packaging case that blocks external light. The method of claim 1, The unit cell is a voltage equalization circuit, characterized in that the ultracapacitor. In the electrical energy storage device used as an industrial power supply, A plurality of unit cells connected in series; A light emitting unit connected in parallel to both ends of each of the unit cells so as to emit light by a voltage applied to both ends of each of the unit cells; And The unit cell receives the light emitted from the light emitting unit, the resistance value increases or decreases according to the intensity of the received light, and the voltage applied to both ends of each unit cell is equalized according to the increase or decrease of the resistance value. And a voltage equalizer connected in parallel to both ends thereof. The method of claim 8, wherein the light emitting unit, A first resistance element; And And a light emitting element connected in series with the first resistance element and emitting light in proportion to the intensity of the voltage. The method of claim 9, The light emitting device is an electrical energy storage device, characterized in that connected in parallel to both ends of the unit cell in the forward direction. The method of claim 9, wherein the voltage equalizer, A second resistance element; And And an optically conductive element connected in series with the second resistance element and having a resistance value that increases or decreases according to the intensity of light. The method of claim 11, And the resistance value decreases as the light intensity increases, and as the light intensity decreases, the voltage equalization circuit increases. The method of claim 11, The light emitting device and the photoconductive device is an electrical energy storage device, characterized in that provided in the packaging case for blocking external light. The method of claim 1, The unit cell is an electric energy storage device, characterized in that the ultracapacitor.

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