KR100793666B1 - Battery Test Apparatus and its Methods - Google Patents

Abstract

An object of the present invention is to provide a battery diagnostic apparatus capable of accurately detecting relatively different capacitances and internal impedances among all battery cells.

The battery diagnostic apparatus of the present invention for achieving the above object, the battery diagnostic apparatus of the present invention is coupled to a power conversion device, in the device for diagnosing at least two or more batteries connected in series, using a Wheatstone bridge method A comparison detector for comparing and detecting internal impedances of at least two batteries of the batteries without noise; A central processing unit for determining whether a difference between internal impedances of the two storage batteries is within a predetermined range; And a status display unit for displaying the determination result of the central processing unit.

Uninterruptible Power Supply, DC Power Supply, Inverter, Converter, Power Converter Battery, Conductance, Impedance, Charge Capability, Discharge Test, Equal Charge, Floating Charge

Description

Battery test device and method {Battery Test Apparatus and its Methods}

1 is a circuit diagram of one embodiment of a general uninterruptible power supply;

2 is a block diagram of a battery diagnostic apparatus according to an embodiment of the present invention,

Figure 3 is a circuit diagram of one embodiment of a battery diagnostic apparatus according to the present invention.

<Brief description of symbols for the main parts of the drawings>

210: comparison detection unit 220: central processing unit

230: status display unit 240: protection circuit

The present invention relates to a battery diagnostic apparatus and method, and more particularly, connected to an uninterruptible power supply, a DC power supply, an inverter, a converter, and the like, and serve as a backup power supply to supply a load when the supply of input power is interrupted. The present invention relates to a battery diagnostic apparatus and method for diagnosing a deterioration state of a battery.

In general, with the development of electronic and communication technology, electronic systems and communication systems for the convenience of life have been developed and used. In order for the electronic and communication systems to operate stably, the power supply must be stable. To this end, an uninterruptible power supply is installed and operated in electronic systems and communication systems.

1 is a circuit diagram of a typical uninterruptible power supply.

The uninterruptible power supply includes a converter 110 for rectifying the applied AC power, an inverter 120 for converting the DC output from the rectifying unit into AC, a bypass unit 130 for directly applying the AC power to the load, A battery 140 and a load 150 for supplying power in an emergency between the converter and the inverter are included.

On the other hand, the uninterruptible power supply is provided with a storage battery to supply power to the electronic system and communication system when the power supply is interrupted due to the occurrence of an unexpected situation. In other words, the electronic system and the communication system operate by receiving power from a storage battery provided in the uninterruptible power supply when the power supply is interrupted. Therefore, the battery provided in the uninterruptible power supply must be charged with power for supplying the electronic system and the communication system in order to prepare for interruption of the power supply.

However, the charge capacity of the battery may be changed due to an increase in impedance due to deterioration (aging), pole corrosion, or a decrease in battery electrolyte due to deterioration of the battery over time, thereby reducing its capacity. In the worst case, when the power supply to the uninterruptible power supply is interrupted, the battery will not be able to supply power for the stable operation of the electronic and communication systems.

To prevent this, inspections of the battery's charge capacity should be made on a regular basis to ensure that it is capable of carrying out its original mission. In particular, there is a state in which the battery is kept in a fully charged state (floating charge state).

In order to solve the above problems, the following methods are used as inspection methods for existing storage batteries.

First, it is a method of supplying power to the load (electronic system and communication system) through the discharge of the battery in a state in which the commercial power applied to the uninterruptible power supply is cut off, and monitors the voltage drop and current amount of the discharged battery. In this method, when the voltage of the discharged battery drops below a certain voltage earlier than the reference time, the battery's voltage and current are measured remotely to determine that the battery is in a bad state.

Second, a method of measuring the state of the battery by measuring the voltage and current of the battery with a portable voltage and current meter.

Third, a method of testing impedance of a battery using a device for checking impedance by applying a predetermined voltage and frequency to two points of a battery anode and a cathode of a cell.

Fourth, the method similar to the third method is a method of measuring and monitoring the change in the impedance of the battery remotely by drawing two points of the positive electrode and the negative electrode for each cell in each cell.

However, the third and fourth methods are a method of transmitting noise having a constant value to the battery, calculating the reflected value to measure the impedance value, and determining the battery state based on the measured impedance value.

In this method, it is inconvenient to accurately determine the peripheral factors, such as the initial impedance value, the manufacturer, the type, the charging capacity, the ambient temperature, and the aging change according to the year of use, in order to measure the charging capacity of the battery.

In addition, such a method can accurately detect whether or not a defective battery is completely removed from the battery, but the frequency transmitted from the diagnostic device for diagnosing the battery is minutely generated from a power converter such as a DC power supply device or an uninterruptible power supply device. The result value is distorted by ripple, so the reliability of the diagnostic value is very low. Even if the battery is discharged from the power converter, the same phenomenon occurs due to the harmonic components generated at the load. Distortion is always present.

For this reason, all kinds of diagnostic devices using frequency emphasize the filtering function for noise, but the measurement is meaningless when connected to the load because the reference frequency is changed by the frequently distorted load.

In particular, the performance and discharge characteristics of a battery are determined by various parameters such as chemical, mechanical and operating environment as well as internal resistance. Therefore, measuring only one element is meaningless. It is only used as a reference for judging the problem.

In addition, the fourth method may induce deterioration of the capacitor by periodically supplying a predetermined value of noise to the battery of the uninterruptible power supply device together with the problem of the third method. This may adversely affect the normal operation of electronic systems (eg, precision industrial devices, medical devices, etc.) and communication systems (eg, wired and wireless communication devices, etc.). In addition, the fourth method requires a large cost for the construction and installation of the inspection apparatus because the measuring point for the inspection of the battery must be configured for each cell of the battery.

An object of the present invention is to provide a battery diagnostic apparatus and method capable of accurately detecting relatively different capacitances and internal impedances among all battery cells.

Another object of the present invention is to provide a battery diagnostic apparatus and method capable of detecting a difference in battery charging capability without sending noise to an object to be measured.

Another object of the present invention is to provide a battery diagnostic apparatus and method capable of accurately detecting an impedance value without being affected by a ripple voltage generated by a power converter and a harmonic component generated by a load. .

Another object of the present invention is to provide an apparatus and method for diagnosing a battery that can accurately detect an impedance in a state in which a battery connected to a power converter is being charged (evenly charged), fully charged (floatingly charged), or discharged. There is this.

In addition, the present invention determines a battery that is relatively degraded among all battery cells irrespective of reference values such as initial impedance value, manufacturer, voltage, type, capacity, and ambient temperature of the battery, as well as reference setting of secular variation according to the use year. Another object is to provide a battery diagnostic apparatus and method.

In addition, another object of the present invention is to provide an apparatus and method for diagnosing a battery capable of determining whether a value detected by an internal impedance of a battery and a voltage imbalance are within a relatively normal range.

The battery diagnostic apparatus of the present invention for achieving the above object is a device for diagnosing at least two or more storage batteries coupled to a power converter, and connected in series, wherein at least two storage batteries of the storage batteries are connected by using a Wheatstone bridge method. A comparison detector for comparing and detecting internal impedances without noise; A central processing unit for determining whether a difference between internal impedances of the two storage batteries is within a predetermined range; And a status display unit for displaying the determination result of the central processing unit.
According to another embodiment, the battery diagnostic apparatus of the present invention further includes a protection circuit unit positioned between the comparison detection unit and the central processing unit to protect the circuit in an inappropriate electrical situation.

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In addition, the battery diagnostic method of the present invention is a method for diagnosing at least two or more batteries coupled to a power conversion device, the internal impedance of at least two batteries of the batteries using the Wheatstone bridge method. Comparing and detecting without; Determining whether a difference between the plurality of impedances is within a predetermined range; And displaying a result according to the determining step.

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Advantageously, the detecting step comprises: providing a third impedance corresponding to a first internal impedance of a first storage battery of the storage battery; Providing a fourth impedance corresponding to a second internal impedance of a second storage battery of the storage battery; And detecting a voltage at both ends applied between the midpoint of the first and second storage batteries and the midpoint of the third and fourth impedances.

Preferably, the determining step includes: a transient state processing step of processing the transient state of the voltage between both ends; Amplifying a weak voltage signal output after the transient state processing step and outputting an amplified voltage signal; Generating first and second reference signals to contrast the amplified voltage signals; And comparing the amplified voltage signal with the first and second reference signals, respectively.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, 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, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

2 is a block diagram of a battery diagnostic apparatus according to an embodiment of the present invention.

According to an embodiment of the present invention, the battery diagnostic apparatus includes a comparison detector 210 for comparing and detecting a plurality of impedances without noise from different battery cells, and for determining whether a difference between the plurality of impedances is within a predetermined range. The central processing unit 220 and a status display unit 230 for displaying the determination result of the central processing unit may be included. According to another embodiment of the present invention, the battery diagnostic apparatus may further include a protection circuit unit 240 positioned between the comparison detection unit 210 and the central processing unit 220 to protect the circuit in an inappropriate electrical situation.

The comparison detector 210 compares and detects the impedance values of the batteries between the nodes A and B and the batteries between the nodes B and C without noise.

In addition, according to an embodiment of the present invention, the status display unit 230 may display a digital value. In addition, according to another embodiment of the present invention, the status display unit 230 may display as an analog value so that the user can easily check the alarm processing or abnormality. In addition, according to one embodiment of the present invention, analog or digital values may be output remotely via a communication network. At this time, the communication network may be any one of the Internet using RS232, RS422, and TCP-IP.

The protection circuit 240 performs a function of protecting the user and the diagnostic apparatus from an overvoltage that may be applied in a transient situation due to an immature operation of a user or a battery failure.

Figure 3 is a circuit diagram of one embodiment of a battery diagnostic apparatus according to the present invention.

The present invention utilizes the theorem of Thevenin, so that the first capacitor C1 and the first resistor Xc1 of the first resistor R1 in the comparison detection unit 210 and the first storage battery between the node B and the node C ( The product of the internal capacitor C (BC) and the internal resistance Xc3 of the internal resistance r (BC) of BA1 is equal to the second impedance Xc2 of the second capacitor C2 and the second resistor R2. It is always equal to the product of the internal capacitor C (AC) of the second storage battery BA2 between the node A and the node C and the internal impedance Xc4 of the internal resistance r (AC), that is, Equation 1 is satisfied. .

Xc1 * Xc2 = Xc3 * Xc4

Therefore, when any one of the internal impedance Xc3 of the first battery or the internal impedance Xc4 of the second battery is changed while the first impedance Xc1 and the second impedance Xc2 are constant, both ends of the detection resistor R3 are changed. Voltage is applied and current is generated.

At this time, the detected value is not only an internal resistance value of the battery but also a comprehensive impedance value as shown in Equation (2).

Here, when the storage battery is installed, the first and second impedances Xc1 and Xc2 are maintained in a resonance state with respect to the internal impedance Xc3 of the first storage battery BA1 or the internal impedance Xc4 of the second storage battery. Capacitors C1 and C2 of appropriate capacitance are provided so that the voltage across the detection resistor R3 is always zero, and the variable resistors R1 and R2 are properly adjusted and fixed.

If an impedance value of an individual battery fixed in an equilibrium state occurs due to deterioration of the battery, a voltage is applied across the detection resistor R3 and detected without noise through IC1 in the comparison detecting unit 210.

The central processing unit 220 processes the transient state of the voltage across the detection resistor R3, the transient state processing unit 221 and the amplifying signal unit 222 for amplifying the weak voltage signal outputted through the transient state processing unit to output the amplified voltage signal. Compares the first and second reference signal generators 223 and 225 and the first and second reference signals with the amplified voltage signal, respectively, to generate the first and second reference signals in order to contrast the amplified voltage signals. First and second comparators 224, 226 for the purpose of designation.

Specifically, the transient state processing unit 221 outputs a voltage signal by blocking a portion of the transient voltage, including resistors R4, R5, and R7 coupled in parallel.

The amplifying signal unit 222 includes an amplifier to amplify the weak voltage signal at an amplification ratio R9 / R6 of the resistor R9 to the resistor R6.

The first and second reference signal generators 223 and 225 may include the variable resistors VR1 and VR2 to designate a maximum allowable range for the impedance change of the battery.

The first and second comparators 224 and 226 receive the first and second reference signals to the inverting terminal (-) and the voltage signals output from the amplifying signal unit 222 to the non-inverting terminal (+). Compare and print.

If the second storage battery BA2 is defective, the display is displayed as a digital or analog value through the resistance R10 in the status display unit 230. If the first storage battery BA1 is defective, the resistance R11 in the status display unit 230 is displayed. Display as digital or analog value.

The varistors C3 and C4 in the protection circuit unit 240 primarily block the surge voltage or overvoltage applied due to a user's inexperienced operation or battery failure, and send them to the resistors R4 and R5 so that they are lower than the resistors R6. Voltage flows into the collector of transistor TR1 through resistor R7.

At this time, when a voltage higher than the reference voltage for transient voltage blocking installed in the comparator IC2 in the protection circuit 240 flows in, a voltage is applied to the base of the transistor TR1 to discharge the transient voltage. Protect.

In addition, in order to prevent failure due to abnormal internal situation such as failure in the diagnosis device, the battery is installed by installing fuses (F1, F2, F3) of suitable capacity immediately after the point where it is brought out in contact with Node A, Node B, and Node C. Protect it.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

According to the present invention, it is possible to accurately detect a minute difference in the internal impedance of a relatively different battery cell among all battery cells. In addition, it does not send noise to the measured object to induce the deterioration of the battery or detect the difference in battery charging capacity as a comparison value of the battery itself without affecting the load of precision industrial equipment, medical equipment, wired / wireless communication equipment, and high frequency equipment. can do. The impedance value can be detected accurately without being affected by the ripple voltage generated by the power converter and the harmonic components generated by the load. It is possible to detect the difference in battery charging capacity even when the battery connected to the power converter is being charged (evenly charged), fully charged (floatingly charged) and discharged. Regardless of the reference value of the initial impedance value, the manufacturer, voltage, type, capacity, and ambient temperature of the battery, as well as the aging change standard according to the year of use, the battery can be judged to be relatively degraded among all battery cells. It is possible to determine whether the value detected by the battery internal impedance and the voltage imbalance is relatively normal range.

Claims (24)

delete An apparatus for diagnosing at least two or more accumulators coupled to a power converter and connected in series, A comparison detecting unit for detecting and comparing the internal impedances of at least two of the batteries without noise by using a Wheatstone bridge method; A central processing unit for determining whether a difference between internal impedances of the two storage batteries is within a predetermined range; And Status display unit for displaying the determination result of the central processing unit Battery diagnostic apparatus comprising a. The method of claim 2, A protection circuit unit positioned between the comparison detection unit and the central processing unit to protect a circuit in an inappropriate electrical situation Storage battery diagnostic device further comprising. The method of claim 3, wherein the comparison detection unit, A third impedance disposed to face the first storage battery among the storage batteries, and to correspond to a first internal impedance of the first storage battery; A fourth impedance disposed opposite to the second storage battery among the storage batteries, and corresponding to a second internal impedance of the second storage battery; A detection resistor connecting the first node, which is the midpoint of the first and second storage batteries, and the second node, which is the midpoint of the third and fourth impedances; And A voltage detector for detecting a voltage across the detection resistor Battery diagnostic apparatus comprising a. The method of claim 4, wherein the central processing unit, A transient state processing unit for processing a transient state of the voltage across the detection resistor; An amplifying signal unit for amplifying the weak voltage signal outputted through the transient state processing unit and outputting an amplified voltage signal; First and second reference signal generators for generating first and second reference signals so as to be contrasted with the amplified voltage signals; And First and second comparators for comparing the first and second reference signals with an amplified voltage signal, respectively Battery diagnostic apparatus comprising a. The method of claim 5, The transient state processor comprises a plurality of resistors coupled in series and parallel. The method of claim 5, The first and second reference signal generators include a variable resistor, the battery diagnostic apparatus that the user can specify the maximum allowable range for the impedance change of the battery. The method of claim 5, The first and second comparators receive the first and second reference signals to the inverting terminal, and the non-inverting terminal receives a voltage signal output from the amplifying signal unit and compares the battery diagnostic device. The method of claim 5, wherein the protection circuit unit, A varistor for breaking a surge voltage or an overvoltage; And A discharge unit including a transistor for discharging when the voltage output from the voltage detector is higher than a predetermined reference voltage Battery diagnostic apparatus comprising a. The method of claim 5, The state display unit, the battery diagnostic device that can transmit the current comparison impedance value and the warning signal of the first storage battery or the second storage battery. The method of claim 5, The state display unit may output a digital command signal for the central processing unit to output the current comparison impedance value of the first storage battery or the second storage battery and to replace the battery when it is determined that the first storage battery or the second storage battery is abnormal. Battery diagnostic device. The method of claim 5, The status display unit, the battery diagnostic device that can output an analog or digital value. The method of claim 12, The analog or digital value can be output remotely via a communication network battery diagnostic apparatus. The method of claim 13, The communication network is a battery diagnostic apparatus of any one of the Internet using RS232, RS422, and TCP-IP. The method of claim 4, wherein And the third and fourth impedances include a resistor and a capacitor in series. delete A method for diagnosing at least two or more accumulators coupled to a power converter and connected in series, Detecting and comparing the internal impedances of at least two of the batteries without noise by using a Wheatstone bridge method; Determining whether a difference between the plurality of impedances is within a predetermined range; And Displaying a result according to the determining step Battery diagnostic method comprising a. The method of claim 17, wherein the detecting step, Providing a third impedance corresponding to a first internal impedance of a first storage battery of the storage battery; Providing a fourth impedance corresponding to a second internal impedance of a second storage battery of the storage battery; And Detecting a voltage at both ends applied between a midpoint of the first and second storage batteries and a midpoint of the third and fourth impedances. Battery diagnostic method comprising a. The method of claim 18, wherein the determining step, A transient state processing step of processing the transient state of the both ends of the voltage; Amplifying a weak voltage signal output after the transient state processing step and outputting an amplified voltage signal; Generating first and second reference signals to contrast the amplified voltage signals; And Comparing the amplified voltage signal with the first and second reference signals, respectively Battery diagnostic method comprising a. The method of claim 19, Generating the first and second reference signals, the battery diagnostic method that the user can specify the maximum allowable range for the impedance change of the battery. The method of claim 19, The displaying of the result may include transmitting a warning signal. The method of claim 19, The displaying of the result may include outputting a digital command signal informing of battery replacement when it is determined that the battery is abnormal. The method of claim 19, The displaying of the result may include outputting an analog or digital value. The method of claim 23, wherein And the analog or digital value is remotely output via a communication system.

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