KR101544215B1 - System for Monitoring Battery State of Health - Google Patents

Abstract

The present invention relates to a battery diagnostic apparatus. More specifically, an impedance equivalent circuit reflecting the metal resistance, internal resistance, capacitance, nonlinear resistance, and inductance value of a polar contact point is constructed to measure an accurate impedance value of a battery, so that an absolute measurement value can be mathematically measured, The present invention relates to a battery diagnosis apparatus capable of preventing an overcurrent, a surge voltage and a short circuit current from being damaged by a circuit by constituting an additional protection circuit using a photocoupler.

To this end, the present invention provides a battery management system comprising: a cell selection unit for selecting a cell so as to enable remote diagnosis of the number of batteries for each cell constituting the battery group; A comparison detector for comparing and detecting a plurality of internal impedances without noise in at least a part of the selected cells; A central processing unit for determining whether a difference between the plurality of impedances is within a predetermined range; And a status display unit for displaying the determination result of the central processing unit.

Uninterruptible Power Supplies, DC Power Supplies, Inverters, Converters, Power Converters, Batteries, Conductance, Impedance, Charging Capacity, Discharge Test, Equalization, Floating Charge

Description

[0001] System for Monitoring Battery State of Health [

The present invention relates to a battery diagnostic apparatus. More specifically, an impedance equivalent circuit reflecting the metal resistance, internal resistance, capacitance, nonlinear resistance, and inductance value of a polar contact point is constructed to measure an accurate impedance value of a battery, so that an absolute measurement value can be mathematically measured, The present invention relates to a battery diagnosis apparatus capable of preventing an overcurrent, a surge voltage and a short circuit current from being damaged by a circuit by constituting an additional protection circuit using a photocoupler.

Electronic and communication systems have been developed and used for convenience of living in accordance with the development of electronic and communication technologies. Stable power supply is essential for stable operation of electronic system and communication system. To this end, uninterruptible power supply devices are installed in electronic systems and communication systems.

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

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

The uninterruptible power supply unit includes a battery, and operates when power is supplied from the battery when the power 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. However, the capacity of the battery may be reduced due to a change in charging characteristics due to an increase in impedance due to aging with time, erosion of poles, decrease in electrolyte, and the like.

In order to prevent this, it is desirable to regularly check the charge capacity of the battery, and the following methods are used for the battery inspection method.

First, power is supplied to the load through the discharge of the battery while the commercial power applied to the uninterruptible power supply is shut off, and the voltage drop and current amount of the discharged battery are monitored.

Second, portable voltage and current meter measures battery voltage and current to measure battery condition.

Third, it is a method of inspecting impedance by applying a constant voltage and frequency to two points of battery anode and cathode of one cell.

Fourth, it is a method to measure impedance change of the battery remotely by drawing two points of anode and cathode to every cell in each cell of the battery.

However, these methods have the inconvenience of accurately grasping peripheral elements such as initial impedance value, manufacturer, type, charging capacity, ambient temperature, and year of use depending on the year of use in order to measure the charging capacity of the battery. In this method, it is possible to accurately detect whether there is a defect in a state in which the battery is completely separated. However, in order to diagnose the battery, the frequency transmitted from the diagnostic device may be a fine Since the result is distorted by ripple and reliability is low, the same phenomenon occurs due to the harmonic components generated in the load even if the battery is separated from the power converter and the battery is discharged. do.

In particular, since the performance and discharge characteristics of a battery are determined not only by internal resistance but also by various parameters such as chemical and mechanical factors and operating environment, it is meaningless to measure only one element. In the field, It is used only as a limited reference for judging the state.

In addition, the fourth method can induce the deterioration of the battery by periodically supplying a constant value of noise to the battery of the uninterruptible power supply with the problem of the third method. This can adversely affect the normal operation of communication systems such as electronic systems such as precision industrial devices, medical devices, and wired / wireless communication devices. In addition, the fourth method requires a lot of cost for the construction and installation of the test apparatus since the measurement point for the test of the battery must be configured for each cell of the battery.

Therefore, it is necessary to study the battery diagnosis device which can confirm the accurate battery number (SOH) value while solving such problems.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method of measuring an absolute value of a battery by mathematically measuring an absolute value, The present invention has been made in view of the above problems.

In order to achieve the above object, a battery diagnosis apparatus according to the present invention includes a cell selection unit for selecting a cell to enable remote diagnosis of the number of batteries for each cell constituting the battery group of the battery group to measure a battery group of batteries; A comparison detector for comparing and detecting a plurality of internal impedances without noise in at least a part of the selected cells; A central processing unit for determining whether a difference between the plurality of impedances is within a predetermined range; And a status display unit for displaying the determination result of the central processing unit.

The battery diagnosis apparatus may further include a protection circuit unit positioned between the comparison detection unit and the central processing unit to protect the circuit.

Each cell constituting the cell selector may be represented by an impedance equivalent circuit including a metal resistance Rm of a polar contact point, an internal resistance Ra, a nonlinear resistor R1 connected in parallel with a capacitance C, and an inductance L. [

In the impedance equivalent circuit, the internal impedance can be calculated by the following equation.

The cell selection unit may further include a switch for selecting the same equivalent circuit as the battery to be measured among the impedance equivalent circuit.

In addition, the battery diagnosis apparatus may further include an additional protection circuit portion including an photocoupler for protecting the switch when the reference voltage or more flows.

In addition, the battery diagnosis apparatus may be classified into a steady state, an error range step, a voltage compensation step by a battery potential difference, an internal impedance difference generation deterioration step, an increase in deterioration and a polar part corrosion step, And the number of battery cells can be displayed in seven steps of disconnection step of polarized part disconnection step, polarity disconnection and inspection.

According to the present invention, an impedance equivalent circuit reflecting the metal resistance, internal resistance, capacitance, nonlinear resistance, and inductance value of the polar contact point is constructed to measure the accurate impedance value of the battery, so that an absolute measurement value can be mathematically measured have.

In addition, according to the present invention, it is possible to prevent the circuit from being damaged by the overcurrent, the surge voltage and the short-circuit current by constructing the additional protection circuit using the photocoupler.

According to the diagnosis apparatus and method for diagnosing a battery according to the present invention, in diagnosing a group of accumulators coupled to a power conversion apparatus, at least some of the accumulators of a group of accumulators are compared with each other using a Wheatstone bridge method, The charging performance can be diagnosed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the preferred embodiments of the present invention will be described below, but it is needless to say that the technical idea of the present invention is not limited thereto and can be variously modified by those skilled in the art.

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

2, the battery diagnosis apparatus includes a cell selection unit 210, a comparison detection unit 220, a central processing unit 230, a status display unit 240, and a protection circuit unit 250, .

The cell selection unit 210 selects a cell so that the number of batteries for each cell can be remotely diagnosed in a group of battery cells in order to measure a group of battery cells.

For example, when the first battery or the second battery is the target, the cell selector 210 may be connected to both the positive (+) and negative (-) terminals of the first battery by the comparison detector 220 Drive the relay contact at point B. Next, when the second battery is to be measured, the positive terminal of the first battery is opened and the negative terminal of the first battery is connected to the comparison detector 220 to drive the relay contact of the point C. If the last cell of the group to be measured is continuously measured in this manner, it is repeated from the first cell again.

In the case of the battery of the "A" type, if the selection switch is set to the "A" position, the battery of the "A" type is selected as the standardized equivalent battery of the battery Lt; / RTI > In the initial installation, errors may occur due to the line resistance depending on the contact resistance of the connection part or the length difference of the detection line for each cell. Therefore, by adjusting n variable resistors (R1 to R3) Is set to be zero.

The equivalent battery according to the present invention takes into account the error due to the line resistance depending on the contact resistance of the connecting portion or the length difference of the detection line. A circuit diagram of such an equivalent battery is shown in FIG.

Referring to FIG. 3, an equivalent battery according to the present invention includes a metal resistance component and a chemical component. The metal resistance component includes the connection terminal resistance component R _TERMINALS , the negative plate corrosion resistance component R _{STRAPS & POSTS} , and the plate resistance variable metal resistance component R _PLATES . The connection terminal resistance component R _TERMINALS varies between 0 and 12% of its contact resistance value. The negative plate corrosion resistance component R _{STRAPS & POSTS} fluctuates between 0 and 25% of contact resistance value between plate. The plate resistance variable metal resistance component R _PLATES fluctuates between 0 and 40% of its contact resistance value.

The chemical element component includes the chemical resistance component R _ELECTROLYTE of the electrolytic solution, the temperature resistance coefficient, the component value according to the material composition ratio, and the like. The chemical resistance component R _ELECTROLYTE of the electrolyte varies between 0 and 15% of its resistance and increases when impurities are produced or depleted. The temperature resistance coefficient fluctuates between 0 and 40% depending on the ambient temperature. Also, the resistance value varies between 0 and 30% depending on the material composition ratio of the equivalent battery such as lead sulfate, lead peroxide, sulfuric acid, and separator.

The impedance Z of the equivalent battery can be expressed by the metal resistance Rm, the internal resistance Ra, the nonlinear resistance Rl, the inductance L, and the like of the contact point such as a polarized line as shown in Equation 1 below. At this time, the metal resistance Rm is a concept including R _{STRAPS & POSTS} and R _PLATES , the internal resistance Ra is a concept including R _TERMINALS , and the nonlinear resistor R 1 is a concept including R _ELECTROLYTE .

By connecting to the equivalent battery and comparing it with the amount of current flowing through the measured battery relative to the equivalent battery through the whistle bridge method and the tebbing theorem, the number of batteries is displayed in seven steps as shown below.

Step 0: Steady state

Step 1: Error range step (daily check)

Step 2: Voltage compensation due to battery potential difference Required step (before replenishment)

Step 3: Internal impedance difference generation deterioration increase step (inspection step)

Step 4: Increase of deterioration and erosion of pole part (emergency maintenance)

Step 5: Increase of Polar corrosion and disconnection of pole part (emergency repair)

Step 6: Disconnection due to polarity disconnection and inspection (emergency)

Primary battery count, secondary cell voltage measurement, tertiary current and temperature measurements are performed, and current and temperature are detected separately through the sensor in the first or last cell of a set.

Referring again to FIG.

The comparison detector 220 compares the number of batteries in each cell with the optimum number of battery cells in the battery cell, and makes a relative diagnosis. The comparison detecting unit 220 compares and detects a plurality of impedances without noise from different battery cells.

Specifically, the comparison detector 220 compares the impedance between the node A and the node B and the impedance between the node B and the node C without noise.

The central processing unit 230 determines whether the difference between the plurality of impedances is within a predetermined range.

The status display unit 240 displays the determination result of the central processing unit 230 and can display the digital value. In addition, the status display unit 240 may display an analog value so that the user can easily check the alarm processing or the abnormality.

The protection circuit unit 250 protects the user and the diagnostic device from overvoltage that may be applied in transient situations due to inactivity of the user or battery failure.

4 is a circuit diagram of a battery diagnosis apparatus according to the present invention.

The first impedance C1 of the comparison detector 220 and the first impedance Xc1 of the first resistor R1 and the impedance of the first capacitor BA1 between the node B and the node C The product of the capacitor C (BC) and the internal impedance Xc3 of the internal resistance r (BC) is the product of the second impedance C2c of the second capacitor C2 and the second impedance Xc2 of the second resistor R2, And the internal impedance Xc4 of the internal capacitor r (AC) of the internal capacitor C (AC) of the second battery cell BA2 between the internal capacitors C and C. That is, the following equation is satisfied.

Xc1 x Xc3 = Xc2 x 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 in a state where the first impedance Xc1 and the second impedance Xc2 are constant, A voltage is applied and a current is generated.

At this time, not only the internal resistance value of the battery but also the integrated impedance value is detected as shown in the following equation.

The first and second impedances Xc1 and Xc2 are set so as to maintain the resonance state with respect to the internal impedance Xc3 of the first battery cell BA1 or the internal impedance Xc4 of the second battery cell, Capacitors C1 and C2 having appropriate capacitances are provided and the variable resistors R1 and R2 are properly adjusted and fixed so that the voltage across both ends of the detection resistor R3 is always zero.

When the impedance value of the individual accumulators fixed in the equilibrium state is unbalanced due to battery deterioration or the like, a voltage is applied across the detection resistor R3 and is detected without noise through IC-1 in the comparison detector 220.

Referring again to FIG.

The central processing unit 230 includes a transient state processing unit 231 for processing the transient state of the voltage across both ends of the detection resistor R3, and an amplification circuit for amplifying the weak voltage signal output through the transient state processing unit 231, A signal unit 232, first and second reference signal generators 233 and 235 for generating first and second reference signals to compare with the amplified voltage signal, first and second reference signals, And first and second comparators 234 and 236, respectively.

Specifically, the transient state processing unit 232 includes resistors R4, R5, and R7 coupled in series and parallel, and outputs a voltage signal by interrupting the transient voltage by a predetermined amount.

The amplified signal portion 232 includes an amplifier and amplifies a weak voltage signal at an amplification ratio (R9 / R6) of a resistor R9 to a resistor R6.

The first and second reference signal generators 233 and 235 may include variable resistors VR1 and VR2 to allow the user to specify the maximum allowable range for the impedance change of the battery.

The first and second comparators 234 and 236 receive the first and second reference signals at the inverting terminal (-) and the voltage signals output from the amplifying signal unit 232 at the non-inverting terminal (+) And outputs it.

If the second battery cell BA2 is defective, the first battery cell BA1 is displayed as a digital or analog value through a resistor R10 in the status display unit 240. If the first battery cell BA1 is defective, Digital or analog value.

The varistors C3 and C4 in the protection circuit unit 250 firstly cut off the surge voltage or the overvoltage applied due to the inactivity of the user or the failure of the battery and send them to the resistors R4 and R5, And a voltage is applied to the collector of the transistor TR1 through the resistor R7.

At this time, when a voltage higher than the reference voltage for transient voltage interrupter installed in the comparator IC2 in the protection circuit unit 250 flows, the transient voltage is applied while the voltage is applied to the base of the transistor TR1, Lt; / RTI > In order to prevent failures due to faulty transient conditions inside the diagnostic device, fuses (F1, F2, F3) with appropriate capacities are installed immediately after the point of contact with the nodes A, B, Protect.

5 is a circuit diagram of another embodiment of a battery diagnosis apparatus according to the present invention. The embodiment of FIG. 5 is similar to the embodiment of FIG. 4 except that a cell selector and an additional protection circuit are provided.

The batteries have various impedances according to the constituent materials, the manufacturing method and the usage and the capacity, and only the limited battery is used for the communication system and the industrial use. The impedance in the optimum state for each type and capacity of the battery can be represented by an equivalent circuit and expressed by the metal resistance Rm of the polar contact point, the internal resistance Ra, the nonlinear resistance R1 and the inductance L (see Equation 1).

311 to 31n constituting the cell selection unit 310 are equivalent circuits of the impedance values calculated and calculated by the method of Equation (1).

The switch 314 plays a role of selecting the same equivalent circuit among the impedance equivalent circuits 311 to 31n as the battery to be measured. That is, any one impedance equivalent circuit selected by the switch 314 serves as R4 in the Wheatstone bridge.

The additional protection circuitry 360 is a protection circuit for overcurrent, surge voltage, and short-circuit current. For example, a DC voltage of 12V for a server, 48V for a rectifier, 400V for UPS, and 720V for a battery is applied to each battery. Thus, if not proper selection is made, the circuit may be damaged by overvoltage and overcurrent, and the additional protection circuitry 360 is to prevent this.

The OP-AMP with IC6 as the center is a comparison amplifier circuit and the appropriate reference voltage is set for each application through RB4. OP-CO1 is a photocoupler which acts to electrically isolate the circuit and acts as a switch to protect the switch 314 when the reference voltage is exceeded and constitutes a closed circuit with R15 and R16.

According to the embodiment of FIG. 5, since the impedance value is calculated by reflecting the metal resistance, internal resistance, capacitance, nonlinear resistance, and inductance of the polar contact point in order to measure the accurate impedance value of the battery, .

It will be apparent to those skilled in the art that various modifications, substitutions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are intended to illustrate and not to limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings . The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be widely applied to the field of battery diagnosis, in particular, in the field of measuring the battery number of a battery used in an uninterruptible power supply for supplying power to an electronic system and a communication system.

1 is a circuit diagram of a general uninterruptible power supply,

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

3 is a circuit diagram showing an equivalent circuit of a battery,

4 is a circuit diagram of a battery diagnosis apparatus according to the present invention.

5 is a circuit diagram of another embodiment of a battery diagnosis apparatus according to the present invention.

Description of the Related Art

210 - cell selector 220 - comparison detector

230 - central processing unit 240 - status display

250 - Protection circuit

Claims (7)

A cell selector for selecting a cell so as to enable remote diagnosis of the number of batteries for each cell constituting the group of the batteries to measure a group of battery batteries; A comparison detector for comparing and detecting a plurality of internal impedances without noise in at least a part of the selected cells; A central processing unit for determining whether a difference between the plurality of impedances is within a predetermined range; A status display unit for displaying a determination result of the central processing unit; And And a protective circuit unit positioned between the comparison detection unit and the central processing unit to protect the circuit. delete The method according to claim 1, Wherein each cell constituting the cell selection unit is represented by an impedance equivalent circuit including a metal resistance Rm of a polar contact point, an internal resistance Ra, a nonlinear resistor R1 connected in parallel with a capacitance C, and an inductance L. The method of claim 3, Wherein the impedance equivalent circuit calculates an internal impedance by the following equation.

The method of claim 3, Wherein the cell selector further comprises a switch for selecting the same equivalent circuit as the battery to be measured among the impedance equivalent circuit. 6. The method of claim 5, Further comprising an additional protection circuit portion including a photocoupler for protecting the switch when the reference voltage or more is inputted. The method according to claim 1, Voltage compensation required by the battery potential difference, step of increasing the internal impedance difference, increase of deterioration, increase of the deterioration and erosion of the polar portion, increase of the erosion of the polar portion, disconnection of the polar portion, And the number of battery cells is displayed in seven disconnection states due to disconnection and inspection.

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