KR20070104110A - Method of monitoring voltage for energy storage device and apparatus using the method - Google Patents

Abstract

A method of monitoring voltage for an energy storage device and a circuit using the same are provided to prevent the damage of the device by informing the abnormality of the device in case that the voltage of a unit cell is greater than an upper limit value or smaller than a lower limit value. A method of monitoring voltage for an energy storage device includes the steps of: detecting the voltage of at least one unit cell(C1) of the energy storage device; generating a logic signal according to the detected voltage level; and generating a detection signal indicating whether the at least one unit cell(C1) is abnormal according to the logic signal. The first step uses a switching device, which is switched on/off at predetermined voltage.

Description

TECHNICAL OF MONITORING VOLTAGE FOR ENERGY STORAGE DEVICE AND APPARATUS USING THE METHOD

1 is a circuit diagram of detecting an abnormality of a unit cell constituting an electric energy storage device according to an exemplary embodiment of the present invention.

2 illustrates a circuit for detecting an abnormality of an electrical energy storage device in which four unit cells are connected in series according to an exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: voltage detector

20: unit circuit

21: light emitting element

22: light receiving element

50: logical operation unit

The present invention relates to an electrical energy storage device, and more particularly, to a voltage monitoring method and a voltage monitoring circuit of the electrical energy storage device.

When a plurality of unit cells are connected in series, if irregularities exist in the characteristics of each unit cell, some unit cells may be in an overcharged state or an overdischarged state. In order to avoid falling into such a state, monitoring of the voltage of each unit cell is performed, and there exists a voltage monitoring apparatus for it.

When electrical energy storage devices such as secondary batteries or ultracapacitors are connected in series to constitute an electrical energy storage device, all unit cells of the secondary battery or ultracapacitors must be operated within the allowable operating voltage range. Various voltage equalization methods are used for this purpose. Detecting whether voltage equalization is maintained is important in that it prevents failure in advance. Therefore, in addition to the voltage equalization circuit, a method of monitoring the voltage of each unit cell is used. It is not difficult to continuously measure the voltages of all unit cells when the number of series connections is small, but in the case of a large number of series connections, the unit cells that constitute the electrical energy storage device to monitor the voltages of all the unit cells in the electrical energy storage device. It is very complicated to connect the voltage detection line to the external voltage monitoring circuit. In order to solve such a complexity, a method of transmitting a voltage of a unit cell to the outside of the electric energy storage device in a time division by installing a communication circuit inside is also used. From the point of view of the user of the electric energy storage device, it is difficult to use a complicated device to know whether the electric energy storage device is normal.

In general, when an abnormality occurs in an electrical energy storage device such as a secondary battery or an ultra capacitor connected in series, most of the abnormality may be determined through voltage detection. The increase in the resistance of a specific unit cell, the decrease in the capacity of a specific unit cell, the increase in the leakage current of a specific unit cell, and the like can all be determined by detecting voltage. In particular, it is important to monitor the existence of a unit cell in which a failure occurs because a failure of a specific unit cell eventually leads to a failure of the entire electrical energy storage device.

An object of the present invention is to provide a voltage monitoring method of an electrical energy storage device that can detect the presence of an abnormality by detecting the voltage of the unit cell.

Another object of the present invention is to provide a voltage monitoring circuit of an electric energy storage device capable of detecting an abnormality by detecting a voltage of a unit cell.

According to an embodiment of the present invention, a voltage monitoring method includes detecting a voltage of at least one unit cell of an electrical energy storage device; Generating a logic signal according to the detected voltage level; And generating a detection signal indicating an abnormality of the at least one unit cell according to the logic signal.

The detecting of the voltage of the at least one unit cell may use a switching device turned on / off at a predetermined voltage.

The generating of the logic signal may include: activating a light emitting device only when the detected voltage level is within a setting range of an operating voltage; And outputting the logic signal by activating the light receiving element according to the output of the light emitting element.

The generating of the logic signal may include: deactivating a light emitting device only when the detected voltage level is within a setting range of an operating voltage; And outputting the logic signal by activating the light receiving element according to the output of the light emitting element.

The light emitting device and the light receiving device may be electrically separated from each other. Generating the logic signal may include outputting the logic signal using an opto coupler.

The generating of the detection signal may include receiving a logic signal and performing an AND operation of outputting a “high” signal only when all unit cells are normal.

Voltage monitoring circuit according to an embodiment of the present invention comprises at least one unit cell constituting the electrical energy storage device; At least one voltage detector detecting a voltage of each of the at least one unit cell by using a switching element turned on / off at a predetermined voltage; At least one unit circuit each generating a logic signal corresponding to a voltage level detected by the at least one voltage detector; And a logic operation unit configured to perform a logic operation on the logic signal to generate a detection signal indicating whether the at least one unit cell is abnormal.

The at least one unit circuit may include a light emitting device that is activated only when the voltage detected by the at least one voltage detector is within a set range; And a light receiving element electrically separated from the light emitting element and outputting the logic signal according to the output of the light emitting element.

The at least one unit circuit may include a light emitting device that is inactivated only when a voltage detected by the at least one voltage detector is within a set range; And a light receiving element electrically separated from the light emitting element and outputting the logic signal according to the output of the light emitting element.

The at least one unit circuit may include an opto coupler.

The logic operation unit may include an AND gate that receives the logic signal and outputs a “high” signal only when all unit cells are normal.

The voltage detection unit may be disposed on one surface of the printed circuit board, and the unit circuit and the logic operation unit may be disposed on the other surface of the printed circuit board.

With respect to the embodiments of the present invention disclosed in the text, specific structural to functional descriptions are merely illustrated for the purpose of describing embodiments of the present invention, embodiments of the present invention may be implemented in various forms and It should not be construed as limited to the embodiments described in.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosure form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for the components.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between. Other expressions describing the relationship between components, such as "between" and "immediately between," or "neighboring to," and "directly neighboring to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is described, and that one or more other features or numbers are present. It should be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. The same reference numerals are used for the same elements in the drawings, and duplicate descriptions of the same elements are omitted.

1 is a circuit diagram of detecting an abnormality of a unit cell constituting an electric energy storage device according to an exemplary embodiment of the present invention. The circuit is a circuit for determining whether an abnormality is detected by detecting a voltage of one unit cell C1 that is connected in series to form an electrical energy storage device.

Referring to FIG. 1, the voltage monitoring circuit of the electrical energy storage device may include a unit cell C1, a voltage detector 10, and a unit circuit 20.

Although the unit cell C1 is illustrated as one capacitor, it is only one embodiment of the present invention, and it is apparent to those skilled in the art that a rechargeable battery such as a lithium and a lithium ion secondary battery cell or an ultra capacitor may be used.

The voltage detector 10 may include resistors R1, R2, R3, R4, and R5 and a switching element U1. The switching device U1 may be a switching device that performs an on / off operation based on a specific voltage, such as a zener diode or a shunt resistor. In the embodiment of the present invention, the switching device U1 is implemented using a programmable voltage reference. In general, the zener diode is used to generate a reference voltage (constant voltage) because the reverse breakdown voltage of the zener diode can be set to a specific voltage during device production. As described above, in the case of a normal zener diode, the breakdown voltage has a fixed value, but the programmable voltage reference U1 may program an output voltage according to a change of a reference input voltage.

The unit circuit 20 may include a light emitting element 21, a light receiving element 22, and a resistor R6. The light emitting element 21 may be formed of a light emitting diode (LED) as an element for converting an electrical signal into an optical signal, and the light receiving element 22 is an element for converting an optical signal into an electric signal. It may be made of a photo diode or a photo transistor.

In the exemplary embodiment of the present invention, the light emitting device 21 and the light receiving device 22 are implemented as one device by using an opto coupler. The optocoupler is responsible for transferring the input and output electrical signals as light. In general, an optical coupling device that combines a light emitting device and a light receiving device into one package to electrically insulate between input and output to transmit a signal as light, also called a photo coupler. Optocouplers are completely isolated between the input and output and are used to carry signals between two circuits with different potential differences. Because signal transmission is unidirectional, there is no influence on the input from the output, the interface with logic elements is easy, and the response speed is fast. And because it is small and light, the mounting density can be increased, the life is semi-permanent, and high reliability. In addition, since the signal is transmitted using light, it has a strong characteristic against noise. An optocoupler is a device that replaces an insulation transformer or an electronic relay that is generally used as a signal interface between circuits having different ground potentials by optically coupling a high insulating material between the light emitting element and the light receiving element. ) Is transferred to the other side with a photo transistor (22) in the electrical insulation state.

Hereinafter, an operation of determining whether there is an abnormality by detecting the voltage of the unit cell C1 will be described in detail.

The upper and lower limits of the operating voltage of the unit cell C1 may be set using a ratio of the resistors R1, R2, R4, and R5. By dividing the voltage of the unit cell C1 by using the resistors R1 and R2, the voltage between both ends of the resistor R2 among the divided voltages is equal to the reference input voltage of the programmable voltage reference U1. Reference Input Voltage). As the voltage of the unit cell C1 is increased or decreased, the voltage of the resistor R2, that is, the reference input voltage of the programmable voltage reference U1 is linearly increased or decreased.

The resistors R4 and R5 divide the voltage of the unit cell C1, so that the LED 21 differs between the voltage of the programmable voltage reference U1 connected to both ends of the LED 21 and the voltage of the resistor R5. Accordingly. That is, the LED 21 is turned on when the voltage of each unit cell C1 is within the set section, and the LED 21 is turned off when the voltage is outside the set section. Of course, it is also possible to reverse the on / off of the LED 21, which is obvious to those skilled in the art.

When the LED 21 is on, a current flows in the photo transistor 22, and when the LED 21 is off, a current does not flow in the photo transistor 22. That is, the photo transistor 22 outputs a "high" or "low" signal used for a logic operation in accordance with the on / off of the LED 21. When the voltage of the unit cell C1 is within the operating voltage range, the LED 21 is turned on so that the photo transistor 22 outputs a logic "high" signal. When the voltage of the unit cell C1 is out of the operating voltage range, the LED 21 is turned off, and the photo transistor 22 outputs a logic "low" signal. The output logic signal is an input of a logical operation unit to be described later.

2 illustrates a circuit for detecting an abnormality of an electrical energy storage device in which four unit cells are connected in series according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the voltage monitoring circuit of the electrical energy storage device includes unit cells C1, C2, C3 and C4, voltage detectors 31, 32, 33, and 34, and unit circuits 41, 42, and 43. And 44) and a logic operation unit 50.

The unit cells C1, C2, C3, and C4 are connected in series to form a battery energy storage device.

The voltage detectors 31, 32, 33, and 34 are connected to the unit cells C1, C2, C3, and C4, respectively, to detect voltages of the unit cells C1, C2, C3, and C4. . Operation of each of the voltage detectors 31, 32, 33, and 34 is the same as that described with reference to FIG. 1.

The unit circuits 41, 42, 43, and 44 are connected to the voltage detectors 31, 32, 33, and 34, respectively, so that the voltage levels detected by each of the voltage detectors 31, 32, 33, and 34, respectively. Generates a logic signal according to

The logic operation unit 50 may include an AND gate 50. The AND gate 50 performs an AND operation on the logic values of the output voltages of the unit circuits 41, 42, 43, and 44. The logic operation unit may be used only when the logic values of the output voltages of the unit circuits 41, 42, 43, and 44 are all high, that is, when the unit cells C1, C2, C3, and C4 are all normal. A high signal is output. In addition, when any one of the logic values of the output voltages of the unit circuits 41, 42, 43, and 44 is “low”, that is, at least one of the unit cells C1, C2, C3, and C4 is present. In this case, the "low" signal is output from the logic operation unit 50. Therefore, it is possible to determine whether there is an abnormality of the entire electrical energy storage device by using the output signal of the logic operation unit 50. In the exemplary embodiment of the present invention, an AND operation is performed using one AND gate, but it is obvious to those skilled in the art that the present invention is not limited thereto.

When power is supplied to the logic operation unit 50 from the outside of the electrical energy storage device, it is possible to operate with three lines of "+" power, "-" power and a signal. Of course, since the electric energy storage device itself is used in the voltage detection unit, the electric energy storage device itself may be used instead of an external power source for the logic operation unit 50. However, in the embodiment of the present invention, the voltage detection units 31, 32, 33, and 34 and the logic operation unit 50 are electrically insulated, and an external power supply is supplied to the logic operation unit 50 because the failure of the logic operation unit 50 does not spread as a failure of the electrical energy storage device. Advantageous to use is the same as described above.

The voltage detectors 31, 32, 33, and 34 are disposed on one surface of a printed circuit board, and the unit circuits 41, 42, 43, and 44 and the logic operator 50 are disposed on the surface of the printed circuit board. It may be disposed on the other side of the printed circuit board.

In particular, as the number of series connections increases, that is, as the voltage of the electrical energy storage device increases, electrical insulation becomes important and difficult. When the number of series connections of the electrical energy storage device is large, the voltage monitoring circuit includes the voltage detectors and the unit circuits as many as the number of unit cells, and includes a logic operation unit for performing a logical operation on the output of the unit circuits. Accordingly, by monitoring only one output signal of the logic operation unit, it is possible to determine whether an abnormality of the entire electrical energy storage device exists.

In the case of using the voltage monitoring method and circuit of the electric energy storage device according to an embodiment of the present invention, there is an abnormality of the electric energy storage device in a simple circuit by an optical method using an opto coupler instead of using a complicated device. It is easy to see.

As described above, the voltage monitoring method according to an embodiment of the present invention monitors whether the unit cell of the electrical energy storage device operates within a set voltage range, and if the voltage value is greater than the upper limit or less than the lower limit, there is an abnormality of the corresponding system. It can prevent the damage of the equipment in advance.

As described above, the voltage monitoring circuit according to an embodiment of the present invention monitors whether the unit cell of the electrical energy storage device operates within a set voltage range, and checks whether there is an abnormality of the corresponding system when the voltage value is larger than the upper limit or smaller than the lower limit. In this way, damage to the equipment can be prevented.

Although described with reference to the examples, those skilled in the art can understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention described in the claims below. There will be.

Claims (13)

Detecting a voltage of at least one unit cell constituting the electrical energy storage device; Generating a logic signal according to the detected voltage level; And And generating a detection signal indicating an abnormality of the at least one unit cell according to the logic signal. The voltage monitoring method of claim 1, wherein the detecting of the voltage of the at least one unit cell comprises using a switching device turned on / off at a predetermined voltage. The method of claim 1, wherein generating the logic signal Activating a light emitting device only when the detected voltage level is within a set range of an operating voltage; And And activating a light receiving element according to the output of the light emitting element to output the logic signal. The method of claim 1, wherein generating the logic signal Deactivating a light emitting device only when the detected voltage level is within a set range of an operating voltage; And And activating a light receiving element according to the output of the light emitting element to output the logic signal. The method of claim 3 or 4, wherein the light emitting element and the light receiving element are electrically separated from each other. 5. The method of claim 3 or 4, wherein generating the logic signal comprises outputting the logic signal using an opto coupler. The method of claim 1, wherein the generating of the detection signal comprises receiving a logic signal and performing an AND operation of outputting a "high" signal only when all unit cells are normal. Voltage monitoring method. At least one unit cell constituting the electrical energy storage device; At least one voltage detector detecting a voltage of each of the at least one unit cell by using a switching element turned on / off at a predetermined voltage; At least one unit circuit each generating a logic signal corresponding to a voltage level detected by the at least one voltage detector; And And a logic calculator configured to perform a logic operation on the logic signal to generate a detection signal indicating whether there is an abnormality in the at least one unit cell. The method of claim 8, wherein the at least one unit circuit A light emitting element that is activated only when the voltage detected by the at least one voltage detector is within a set range; And And a light receiving element electrically separated from the light emitting element and outputting the logic signal in accordance with the output of the light emitting element. The method of claim 8, wherein the at least one unit circuit A light emitting device which is inactivated only when the voltage detected by the at least one voltage detector is within a set range; And And a light receiving element electrically separated from the light emitting element and outputting the logic signal in accordance with the output of the light emitting element. The voltage monitoring circuit of claim 8, wherein the at least one unit circuit comprises an opto coupler. The voltage monitoring circuit of claim 8, wherein the logic operation unit comprises an AND gate that receives the logic signal and outputs a “high” signal only when all of the unit cells are normal. The voltage monitoring circuit of claim 8, wherein the voltage detection unit is disposed on one surface of the printed circuit board, and the unit circuit and the logic operation unit are disposed on the other surface of the printed circuit board.

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