KR102581545B1 - Method for Verificating quality of Lead Acid Battery - Google Patents

Abstract

The present invention relates to a method for verifying the quality of a lead acid battery, comprising: classifying failure modes according to the cause of failure; Deriving first essential characteristics by evaluating the impact of each failure mode; Establishing suitability criteria for each of the first essential characteristics; Testing the first essential characteristic for a lead acid battery to be verified; Comparing the results of the test with the judgment criteria to determine the quality of the lead acid battery to be verified; preparing second essential characteristics for verification after installation of the lead acid battery subject to verification; and determining whether the second essential characteristic is satisfied after installing the lead acid battery to be verified.

Description

{Method for Verifying quality of Lead Acid Battery}

The present invention relates to a method for verifying the quality of lead acid batteries.

Due to the contraction of the nuclear industry, the supply of nuclear-grade components is becoming increasingly difficult due to discontinuation of nuclear-grade components and bankruptcy of manufacturers.

Due to this situation, lead acid batteries are also upgraded to meet the safety quality level by applying the General Standard Product Quality Verification (CGID, Commercial Grade Item Dedication) methodology when used in safety-grade devices at U.S. nuclear power plants.

In the case of domestic nuclear power plants, detailed standards like those in the United States have not yet been established, and it is necessary to establish quality verification evaluation procedures and methodologies for general standard products for use in nuclear safety grade devices.

Korea Registered Patent No. 10-1876632 (announced on July 9, 2018)

The purpose of the present invention is to provide a method for verifying the quality of lead acid batteries.

The object of the present invention is to provide a quality verification method for a lead acid battery, comprising: classifying failure modes according to the cause of failure; Deriving first essential characteristics by evaluating the impact of each failure mode; Establishing suitability criteria for each of the first essential characteristics; Testing the first essential characteristic for a lead acid battery to be verified; Comparing the results of the test with the judgment criteria to determine the quality of the lead acid battery to be verified; preparing second essential characteristics for verification after installation of the lead acid battery subject to verification; and determining whether the second essential characteristic is satisfied after installing the lead acid battery to be verified.

The first essential characteristic may include rated capacity and output voltage.

The second essential characteristic may include essential characteristics before replacement, essential characteristics after replacement, and essential characteristics after connection to the charger.

The essential characteristics before replacement include the unit cell voltage after a second charge, the electrolyte temperature after a second charge, and the converted specific gravity of each unit cell, and the essential characteristics after replacement include contact resistance between unit cells, contact resistance between columns, and contact resistance between mounts. It includes, and the essential characteristics after connecting the charger may include the voltage of the unit cell, the electrolyte temperature, the converted specific gravity of each unit cell, and the storage battery terminal voltage.

The failure mode may include a decrease in discharge voltage and capacity.

The lead acid battery can be used in nuclear power plants.

According to the present invention, a method for verifying the quality of a lead acid battery is provided.

Figure 1 shows the fully charged state of a lead acid battery,
Figure 2 shows the discharging process of a lead acid battery,
Figure 3 shows the charging process of a lead acid battery,
Figure 4 shows a method for verifying the quality of a lead acid battery according to an embodiment of the present invention.
Figure 5 shows the failure mode effect analysis and first essential characteristic derivation of a lead acid battery in an embodiment of the present invention;
Figure 6 shows a circuit diagram for measuring the rated capacity of a lead acid battery;
Figure 7 shows a circuit diagram for measuring the output voltage of a lead acid battery.

The present invention will be described in more detail below with reference to the drawings. The attached drawings are only an example to explain the technical idea of the present invention in more detail, so the idea of the present invention is not limited to the attached drawings.

A lead acid battery can perform the function of converting chemical energy into electrical energy to supply power (discharging) and the function of converting electrical energy supplied from an external power source into chemical energy (charging).

As shown in Figure 1, in a fully charged state, the positive (+) plate may be lead peroxide (PbO2), the negative (-) plate may be spongy lead (Pb), and the electrolyte may be dilute sulfuric acid (H2SO4).

Discharge refers to the process of converting chemical energy into electrical energy. When a load is connected to the cathode plate and the anode plate, the current (I) in the external circuit flows from the anode to the cathode through the load, and electrons can move from the cathode to the anode.

The flow of current in the electrolyte solution can be achieved by H+ ions being transported from the cathode plate to the anode plate.

As shown in Figure 2, lead peroxide (PbO2) can be converted into lead sulfate (PbSO4) by absorbing electrons in the positive electrode plate.

The cathode plate emits electrons so that spongy lead (Pb) can be converted to lead sulfate (PbSO4).

After discharge, both the lead peroxide (PbO2) on the positive plate and the spongy lead (Pb) on the negative plate are changed to lead sulfate (PbSO4), so electromotive force may not be generated.

At this time, after the sulfuric acid solution is ionized, water can be generated through an ionic reaction.

Charging refers to the process of converting electrical energy into chemical energy using a charger. When charging, the external power source, that is, the positive electrode of the charger and the positive electrode of the lead-acid battery, and the negative electrode of the charger and the negative electrode of the lead-acid battery can be connected to each other.

Charging current can flow from the anode to the cathode through the load inside the lead acid battery.

As shown in Figure 3, lead sulfate (PbSO4) can be converted to lead peroxide (PbO2) while emitting electrons from the positive plate.

In the negative plate, lead sulfate (PbSO4) can be converted to spongy lead (Pb) by attracting electrons.

At this time, water can be converted into a sulfuric acid solution.

In nuclear power plants, lead acid batteries can be classified as active devices because they perform the function of converting chemical energy into electrical energy to supply power (discharging) and the function of converting electrical energy supplied from an external power source into chemical energy (charging). .

Additionally, lead acid batteries can perform the safety function of supplying power using conversion of chemical energy and electrical energy.

Referring to Figure 4, the quality verification method of the lead acid battery according to the present invention will be described.

First, classify the failure mode according to the cause of the failure (S100). Failure modes may include degradation of discharge voltage and capacity.

As shown in Figure 5, causes of lead acid battery failure may include long-term discharge, high discharge current, insufficient charging repetition, contamination of impurities, lack of electrolyte, shock, corrosion, contamination, high charging voltage, overcharging, etc.

The stage of analyzing the effects of the failure mode considering the function of the lead-acid battery includes the sulfation phenomenon of the lead-acid battery, corrosion of the electrode plates, short circuit due to damage to the internal separator, loosening and corrosion of the connection, decrease in discharge voltage and capacity of the lead-acid battery, etc. This can be.

The first essential characteristics of a lead-acid battery can be evaluated through failure mode classification and impact analysis according to one or more failure causes of the lead-acid battery.

Afterwards, the impact of each failure mode is analyzed to derive the first essential characteristic (S110).

The first essential characteristic may include rated capacity and output voltage.

Rated Capacity is the amount of electricity that can be extracted in a fully charged state under the conditions of specified temperature, discharge current, and termination voltage, and is a standard value representing the capacity of a lead acid battery.

Output Voltage refers to the standard voltage used to display lead acid battery voltage.

Next, the second essential characteristic, which is a verification item after installation, is derived (S200).

The second essential characteristic may include essential characteristics before replacement, essential characteristics after replacement, and essential characteristics after connecting the charger.

Required characteristics before replacement may include the unit cell voltage after a second charge, the electrolyte temperature after a second charge, and the converted specific gravity of each unit cell.

Converted specific gravity is the specific gravity converted from the standard temperature to 25°C, and can be obtained using the following formula.

[Formula 1]

S25 = ST + 0.0006(T - 25)

Here, S25 is the specific gravity converted from the standard temperature to 25°C, ST = the actual specific gravity at T°C, and T is the actual measured temperature of the electrolyte solution.

Required characteristics after replacement may include contact resistance between unit cells and contact resistance between the rearmost unit cell and the rug and booth.

After connecting the charger, essential characteristics may include the voltage of the unit cell, electrolyte temperature, converted specific gravity of each unit cell, and storage battery terminal voltage.

Afterwards, suitability criteria are prepared for each first essential characteristic and second essential characteristic (S300). The decision standard preparation stage may be carried out at different times for each first essential characteristic and second essential characteristic.

Lead acid battery manufacturer, model name, voltage, capacity (Ampere Hr. Capacity@20Hrs), cold starting ability (CCA: Cold Cranking Ampere), and reserve capacity (RC: Reserve) of the lead acid battery specified in the catalog, data sheet, or product surface of existing lead acid battery products. By checking Capacity, etc., it is possible to establish suitability criteria for the first essential characteristic.

Additionally, the shape of the lead acid battery can be prepared by checking whether it is identical to the specifications described in the catalog or data sheet provided by the manufacturer.

Before use, lead acid batteries can be checked for imitations, counterfeit products, and suspect parts (CFSI) to confirm that they are genuine and that they are normal parts without any traces of use or defects.

For lead acid batteries, you can check whether the dimensions specifications described in the catalog or data sheet provided by the manufacturer are the same.

The order in which each step described above is performed is not limited.

Next, the first essential characteristic and the second essential characteristic are tested for the lead acid battery to be verified (S400).

The first essential characteristic can be verified by testing the lead acid battery subject to verification.

To check the rated capacity of a lead acid battery, the IEC 61056-1 test method can be used.

Rated Capacity can be used to determine whether power can be supplied until the terminal voltage is reached by discharging the current for a set period of time.

First, fully charge the lead acid battery at a constant voltage at an ambient temperature of (25 ± 2) ℃. During 6 hours or two consecutive operating periods, the current is 0.1 Charge until there is no change.

After full charging, the test piece is kept in an unloaded state for 5 to 24 hours and then discharged at the specified discharge current.

Measure the rated capacity of the discharged lead acid battery.

The discharge time (t) at the point when the terminal voltage reaches the specified discharge end voltage is measured and the rated capacity is calculated using [Equation 2].

[Formula 2]

From here is the actual capacity (Ah), is the discharge current (A) with a discharge time of 20 hours for a final voltage of 1.75 V/Cell, is the discharge current (A) with a discharge time of 1 hour for a final voltage of 1.60 V/Cel1.

Rated Capacity must be more than 95% of the capacity specified by the manufacturer when discharging and charging unless otherwise specified.

To check the output voltage of a lead acid battery, the IEC 61056-1 test method can be used.

You can check the output voltage after natural discharge without load for a certain period of time.

First, fully charge the lead acid battery at a constant voltage at an ambient temperature of (25 ± 2) ℃. After full charging, the test piece is kept in an unloaded state for 5 to 24 hours and then the output voltage is measured.

Measure the voltage between the terminals of the lead acid battery. Output Voltage must be higher than the value specified by the manufacturer.

The test procedure and conformity judgment criteria for the second essential characteristic of post-installation verification are as follows.

If the electrolyte falls below the upper limit, replenish it up to the upper limit, connect the charger and storage battery, and start charging.

During charging, the temperature of the electrolyte, specific gravity, charging current, and room temperature are recorded. After charging, check that the electrolyte specific gravity is 1.205~1.225 (based on 25℃). If it exceeds it, replenish distilled water.

After charging, perform floating charging. When floating charging before installation, the charging voltage per cell is 2.10~2.22(V).

Required characteristics before replacement may include the unit cell voltage after a second charge, the electrolyte temperature after a second charge, and the converted specific gravity of each unit cell.

After a second charge, the unit cell voltage may be 2.05V to 3.91V, 2.08V to 3.1V, or 2.10V to 3.0V.

The electrolyte temperature after initial charging may be 19.3 to 42°C, 18.3 to 45°C, or 21.3 to 45°C.

The converted specific gravity of each unit cell may be 1.200 to 1.220, 1.205 to 1.250, or 1.210 to 1.350.

Required characteristics after replacement may include contact resistance between unit cells, contact resistance between columns, and contact resistance between mounts.

The contact resistance between unit cells may be 55μΩ or less, 58μΩ or less, or 60μΩ or less, or is 90% to 120% of the initial measured value.

The contact resistance between columns and mounts may be 55 μΩ or less, 58 μΩ or less, or 60 μΩ or less, or 90% to 120% of the initial measured value.

After connecting the charger, essential characteristics may include the voltage of the unit cell, electrolyte temperature, converted specific gravity of each unit cell, and storage battery terminal voltage.

The unit cell voltage may be 2.13V to 2.22V, 2.15V to 2.19V, or 2.25V to 2.4V.

The electrolyte temperature may be 18.3 to 42°C, 18.8 to 45°C, or 19.3 to 45°C.

The converted specific gravity of each unit cell may be 1.200 to 1.220, 1.205 to 1.250, or 1.210 to 1.350.

The storage battery terminal voltage may be 124.7 to 125.7 V, 124.7 to 125.8 V, or 124.9 to 125.6 V.

Finally, quality judgment is made by comparing the suitability criteria and test results (S500). Quality judgment can be determined as acceptable or non-compliant. Suitability can be determined when the suitability criteria for all essential characteristics are satisfied, or when the suitability criteria for essential characteristics are met for a certain percentage or more.

If the suitability criteria for the first essential characteristic are not met, the second essential characteristic, which is the verification standard after installation, may not be tested.

According to the quality verification method and device for standard lead acid batteries for replacement with the nuclear power plant safety grade according to an embodiment of the present invention, it can be replaced with the nuclear power plant safety grade that can produce the same verification results regardless of the experience and skill level of the evaluator. Quality verification of standard lead acid batteries for use can be performed.

In addition, in order to perform quality verification, it is the most important standardized technical standard and has the advantage of efficiently applying general standard product verification work for nuclear safety grade equipment, and when applied to organizations preparing to perform quality verification and new evaluators, it is possible to provide replacement products. It is possible to secure quality and perform quality verification quickly and reliably. Furthermore, when applied to the same industry as nuclear power plant safety grade maintenance materials, it is possible to increase technological capabilities and create results with uniformity and reliability, which has the advantage of securing the quality and stable supply of nuclear power plant safety grade maintenance materials.

As the specific parts of the present invention have been described in detail above, it is clear to those skilled in the art that these specific techniques are merely preferred embodiments and do not limit the scope of the present invention. something to do. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (6)

In the quality verification method of lead acid batteries,
Classifying failure modes according to the cause of failure;
Deriving first essential characteristics by evaluating the impact of each failure mode;
Establishing suitability criteria for each of the first essential characteristics;
Testing the first essential characteristic for a lead acid battery to be verified;
Comparing the results of the test with the judgment criteria to determine the quality of the lead acid battery to be verified;
preparing second essential characteristics for verification after installation of the lead acid battery subject to verification; and
After installing the lead acid battery subject to verification, it includes determining whether the second essential characteristic is satisfied,
The second essential characteristics include essential characteristics before replacement, essential characteristics after replacement, and essential characteristics after connecting the charger,
The essential characteristics before replacement include the unit cell voltage after a second charge, the electrolyte temperature after a second charge, and the converted specific gravity of each unit cell,
The essential characteristics after the replacement include contact resistance between unit cells, contact resistance between columns, and contact resistance between mounts,
After connecting the charger, the essential characteristics are the voltage of the unit cell, the temperature of the electrolyte, the converted specific gravity of each unit cell, and the battery terminal voltage. A method of verifying the quality of a lead acid battery. According to paragraph 1,
The first essential characteristic is a quality verification method of a lead acid battery including rated capacity and output voltage. delete delete According to paragraph 1,
A method of verifying the quality of a lead acid battery in which the failure mode includes a decrease in discharge voltage and capacity. According to paragraph 1,
The above is a method of verifying the quality of lead acid batteries used in nuclear power plants.

Images