ASTM D7148-19a

Standard Test Method for Determining the Ionic Resistivity (ER) of Alkaline Battery Separator Using a Carbon Electrode in an Electrolyte Bath Measuring System

SIGNIFICANCE AND USE
5.1 The ER of a battery separator is a standard measurement used by separator and battery manufacturers for quality control purposes and separator selection.  
5.2 Separator ER and the separator's interaction with the electrolyte, that is resistance to wetting or flow, will contribute to the internal resistance of the battery and this has the potential to limit the electrical output of a battery. The ER determination is a tool for battery manufacturers to use in design, material selection, and performance specifications.  
5.3 The change in the bath electrical resistance imparted by a separator is affected by the porosity, thickness, and tortuousity of the pore structure of the separator, the wettability of the separator to the electrolyte, and the temperature and concentration of the electrolyte.  
5.4 Incomplete wetting or saturation of the pore structure limits the lowest ER value obtainable from a separator structure. Separators are pretreated to assure that the specimen being tested has been adequately wetted out. A separator that is not fully wetted out (saturated) will give a higher ER.  
5.5 This test method is intended to give a rapid and repeatable measurement that approximates the change in ER that could happen when the separator is used in a battery.
SCOPE
1.1 This test method covers the pretreatment, test conditions, apparatus, and procedure to determine the ionic resistivity, commonly referred to in the battery industry as electrical resistance (ER) of an alkaline battery separator immersed in an electrolyte of 40 % potassium hydroxide (KOH).  
1.2 The values stated in SI units are to be regarded as the standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Oct-2019
• ICS: 29.220.30 - Alkaline secondary cells and batteries
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.01 - Electrical Insulating Products

Relations

• Refers: ASTM D1711-24 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Mar-2024
• Refers: ASTM E2935-17 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Oct-2017
• Refers: ASTM E2935-16 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 15-Nov-2016
• Refers: ASTM D1711-15 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Nov-2015
• Refers: ASTM E2935-15 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Oct-2015
• Refers: ASTM D1711-14a - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Nov-2014
• Refers: ASTM E2935-14 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Oct-2014
• Refers: ASTM D1711-14 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-May-2014
• Refers: ASTM D1711-13 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Nov-2013
• Refers: ASTM E2935-13 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Aug-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM D1711-11a - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Aug-2011
• Refers: ASTM E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008
• Refers: ASTM D1711-08 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-May-2008

Overview

ASTM D7148-19a is a standard test method developed by ASTM International for determining the ionic resistivity (ER) of alkaline battery separators using a carbon electrode in an electrolyte bath measuring system. Ionic resistivity, also commonly referred to as electrical resistance (ER) in the battery industry, is a critical property influencing battery performance, internal resistance, and output. This standard guides separator and battery manufacturers in performing repeatable, accurate measurements for quality control and separator selection, particularly for alkaline batteries using a 40% potassium hydroxide (KOH) electrolyte solution.

Key Topics

• Purpose of Testing: ER measurements are essential for quality control and material selection in battery manufacturing. They help ensure that battery separators enable efficient ion transfer and do not add excessive internal resistance to the finished battery.
• Factors Affecting ER: Test results are influenced by separator porosity, thickness, tortuosity, pore structure, and how well the separator is wetted by the electrolyte. Temperature and concentration of the KOH solution also have significant effects.
• Rapid, Repeatable Measurement: The method provides a fast and reproducible way to approximate real-world changes in ER when separators are used in batteries.
• Pretreatment and Sample Preparation: Complete wetting or saturation of separator specimens is critical. Inadequate wetting may yield artificially high ER values. The document outlines proper sample pretreatment and apparatus setup to ensure accuracy.
• Measurement Procedure: The ER is determined by measuring the change in resistance in an electrolyte bath with and without the separator specimen placed between carbon electrodes. Specific calculation methods and reporting requirements are provided, emphasizing reproducibility and standardization.

Applications

• Separator Quality Assurance: Battery and separator manufacturers utilize this standard to monitor the consistency and suitability of separator materials during production and prior to use in battery assembly.
• Battery Design and Performance: By accurately characterizing the ER of various separator options, battery designers can select materials that minimize internal resistance and maximize electrical output, charge retention, and life cycle.
• Material Research and Development: Researchers engaged in developing advanced battery separators use ASTM D7148-19a to benchmark new compositions versus established materials.
• Regulatory Compliance: This standardized approach aids in meeting internationally recognized measurement practices, supporting compliance with technical barriers to trade provisions and ensuring comparability across industries.

Related Standards

• ASTM D1711: Terminology Relating to Electrical Insulation – defines relevant terms used in ER testing.
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method – informs interlaboratory validation procedures.
• ASTM E2935: Practice for Conducting Equivalence Testing in Laboratory Applications – supports method validation and equivalence studies.
• Battery Council International Test Method: Standard for measuring battery separator resistance using alternative measuring systems.

Practical Value

Implementing ASTM D7148-19a in quality control and R&D ensures that alkaline battery separators meet stringent industry expectations for ionic resistivity. Accurate ER assessment directly impacts battery performance, energy efficiency, and operational life. Adhering to this method helps manufacturers maintain competitive advantage, minimize costly recalls, and facilitate international trade of battery components. By providing a consistent, reliable approach to measuring separator ER, this test method supports innovation and high standards in the battery industry.

Keywords: ASTM D7148-19a, ionic resistivity, electrical resistance, alkaline battery, battery separator, ER measurement, potassium hydroxide electrolyte, separator quality control, battery performance, ASTM standard.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7148 − 19a
Standard Test Method for
Determining the Ionic Resistivity (ER) of Alkaline Battery
Separator Using a Carbon Electrode in an Electrolyte Bath
Measuring System
This standard is issued under the fixed designation D7148; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* System, Section 3.3b
1.1 This test method covers the pretreatment, test
3. Terminology
conditions, apparatus, and procedure to determine the ionic
3.1 Definitions of Terms Specific to This Standard:
resistivity, commonly referred to in the battery industry as
3.1.1 barrier resistance (RB), n—the resistance of the bath
electrical resistance (ER) of an alkaline battery separator
with a solid, nonporous sheet of alkaline resistant, electrical
immersed in an electrolyte of 40 % potassium hydroxide
insulation that separates the electrodes.
(KOH).
3.1.2 bath resistance (RC), n—the resistance of the bath
1.2 The values stated in SI units are to be regarded as the
without the specimen (separator).
standard.
3.1.3 bath resistance (RT), n—the total electrical resistance
1.3 This standard does not purport to address all of the
of the bath and a separator specimen.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1.4 battery separator, n—an ion-permeable, nonconduc-
priate safety, health, and environmental practices and deter- tive material that prevents electrical contact between electrodes
mine the applicability of regulatory limitations prior to use. of opposite polarity.
1.4 This international standard was developed in accor-
3.1.5 electrolyte, n—a 40 % potassium hydroxide solution.
dance with internationally recognized principles on standard-
3.1.6 ionic resisitivity (ER), n—the product of a change in
ization established in the Decision on Principles for the
electrical resistance times an area.
Development of International Standards, Guides and Recom-
3.1.6.1 Discussion—The area is the aperture area divided by
mendations issued by the World Trade Organization Technical
the number of separators between the electrodes. The change in
Barriers to Trade (TBT) Committee.
resistance is the difference, in ohms, of the electrical resistance
with and without the seperator(s). The SI units for ER are
2. Referenced Documents
ohms-metre but the customary practice in the battery industry
2.1 ASTM Standards:
is to report the ER in units of ohms-cm . This terminology is
D1711 Terminology Relating to Electrical Insulation
not in conflict with Terminology D1711.
E691 Practice for Conducting an Interlaboratory Study to
3.2 Symbols:
Determine the Precision of a Test Method
3.2.1 ER—a symbol, peculiar to the battery industry, denot-
E2935 Practice for Evaluating Equivalence of Two Testing
ing that characteristic of a sheet material that is related to the
Processes
rate of transfer of ions through the interstices of a porous sheet
2.2 Battery Council International:
immersed between two carbon electrodes in an aqueous
Standard Test Method for Determining the Electrical Resis-
electroyte.
tance of a Battery Separator Using a Palico Measuring
4. Summary of Test Method
4.1 This test method detects small changes in ohmic resis-
This test method is under the jurisdiction of ASTM Committee D09 on
Electrical and Electronic Insulating Materials and is the direct responsibility of tance between carbon electrodes immersed in an alkaline
Subcommittee D09.01 on Electrical Insulating Products.
electrolyte with and without separator material between the
Current edition approved Nov. 1, 2019. Published November 2019. Last previous
carbon electrodes. This change is related to the rate of transfer
edition approved in 2019 as D7148 – 19. DOI: 10.1520/D7148-19A.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from Battery Council International, 330 N. Wabash Ave., Ste. 2000,
the ASTM website. Chicago, IL 60611.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7148 − 19a
of ions through a separator material. The ER is calculated from 8. Hazards
the fixed aperture area. The sensitivity and resolution of the
8.1 Safety goggles and face shield, lab coat, and rubber
apparatus detects electrical resistance changes of 60.1 %.
apron and gloves must be worn during KOH dilution opera-
tions. Enclose the glass-mixing bottle in a plastic container of
5. Significance and Use
sufficient capacity to contain the solution in case of bottle
5.1 The ER of a battery separator is a standard measurement
breakage. To prevent excessive heating, add concentrated KOH
used by separator and battery manufacturers for quality control
slowly to water with adequate agitation to produce thorough
purposes and separator selection.
mixing. The diluted KOH is sufficiently corrosive at both
ambient and elevated temperatures that careful handling is
5.2 Separator ER and the separator’s interaction with the
necessary to prevent injury or damage.
electrolyte, that is resistance to wetting or flow, will contribute
to the internal resistance of the battery and this has the potential
8.2 The hazard associated with mixing KOH with water is
to limit the electrical output of a battery. The ER determination
that it generates a lot of heat as it dissolves; this has the
is a tool for battery manufacturers to use in design, material
potential to lead to spattering. A concentrated KOH solution
selection, and performance specifications.
will erode skin and eyes. Avoid these hazards by wearing safety
glasses, face shield, and protective gloves, and immediately
5.3 The change in the bath electrical resistance imparted by
rinsing with water if any skin contact occurs. (If any eye
a separator is affected by the porosity, thickness, and tortuous-
contact occurs, flush the eyes with water for 15 min and then
ity of the pore structure of the separator, the wettability of the
get medical attention.)
separator to the electrolyte, and the temperature and concen-
tration of the electrolyte.
9. Sampling, Test Specimens, and Test Units
5.4 Incomplete wetting or saturation of the pore structure
9.1 Select samples representative of the separator material
limits the lowest ER value obtainable from a separator struc-
to be tested.
ture. Separators are pretreated to assure that the specimen
9.2 Use a specimen size of at least 120 by 120 mm and no
being tested has been adequately wetted out. A separator that is
larger than what will fit in the bath.
not fully wetted out (saturated) will give a higher ER.
9.3 If specimens require identification, use an alkaline
5.5 This test method is intended to give a rapid and
resistant marker. Mark an area of the specimen that will not
repeatable measurement that approximates the change in ER
interfere with the ion transfer through the separator.
that could happen when the separator is used in a battery.
10. Preparation of Apparatus
6. Apparatus
10.1 Fill the ER bath with prepared battery electrolyte (40
6.1 Stainless steel container or equivalent to accommodate
6 1 % KOH solution) to a level above the aperture opening (12
the separator test samples.
to 25 mm below the top of the ER bath). Adjust the bath’s
6.2 Hot plate or other heating device suitable to boil water.
temperature to 25 6 5°C .
6.3 Stainless steel screen.
10.2 Connect the electrodes to the resistance meter control
unit using alkali-resistant wire and hardware.
6.4 Glass or plastic separator tank for presoaking separators
in battery electrolyte.
10.3 Turn on the resistance meter. Allow the equipment to
stabilize for at least 20 min. If the meter includes a standard
6.5 Interval timer.
reference resistor (place in “Standby” mode and “Standard”
6.6 Safety glasses.
scaling on the resistance meter control unit and set to the
6.7 Thermometer.
appropriate resistance range scale for a 0.14-Ω resistor read-
ing). Unless the meter reading is within 60.1 % of the value of
6.8 Alkaline resistant gloves, that is neoprene latex or
the resistor, service will be required.
polyethylene gloves.
10.4 If available, check the resistance standard for the
6.9 Plastic tongs for handling KOH-wetted separators.
system outlined in 11.4. If this agrees within 61 %, proceed to
6.10 ER bath with a fixed aperture area (32 cm is standard)
Section 13.
that puts a uniform current flux through a fixed area of the
10.5 Periodically, or when problems occur or changes are
separator sample for measurement. A drawing of an ER bath is
made to the system, test the stability, polarization, current
included in Annex A1.
leakage, and standardization using the maintenance procedures
6.11 A.C. resistance meter or bridge with sufficient sensi-
set forth in Section 11.
tivity and resolution to measure 60.1 % change in the ER bath
resistance in the presence of potentials generated in the ER
11. Testing and Maintenance of Equipment
bath.
11.1 Stability of Equipment:
11.1.1 Check the resistance of the ER bath. (Place the meter
7. Reagents and Materials
in “Operate” mode and “Standard” scaling and press “Reset.”
7.1 Distilled or deionized water.
Set the appropriate resistance range to give the maximum
7.2 Reagent grade KOH. meter reading without going off scale.)
D7148 − 19a
11.1.2 Agitate the electrolyte to make certain that the 11.4.4 In the resistance measuring system, it is possible to
temperature and concentration are uniform. set the meter to “Scaled” mode and to press the “Preset” switch
with the plastic standard in the test area with a closed slide.
11.1.3 Ensure the bath resistance (RC) is constant within
60.5 % at a given temperature and electrolyte concentration. When the standard is removed, ensure that the reading on the
meter equals the standardized value within 61 % when cor-
11.1.4 If readings are inconsistent, proceed to 11.2 and 11.3
for polarization and leakage determination. rected for temperature.
11.4.5 Clean the surfaces of the bath and the surroundings
11.2 Polarization of Equipment:
after each use to remove spilled electrolyte on the surfaces and
11.2.1 Polarization affects the reading of any resistance
connections. Ensure that the resistance meter is far enough
measuring system differently. Follow manufacturer instruc-
from the KOH bath to prevent fumes from corroding the meter.
tions.
Check and if necessary adjust the electrolyte to the proper
11.2.2 For the res
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7148 − 19 D7148 − 19a An American National Standard
Standard Test Method for
Determining the Ionic Resistivity (ER) of Alkaline Battery
Separator Using a Carbon Electrode in an Electrolyte Bath
Measuring System
This standard is issued under the fixed designation D7148; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the pretreatment, test conditions, apparatus, and procedure to determine the ionic resistivity,
commonly referred to in the battery industry as electrical resistance (ER) of an alkaline battery separator immersed in an electrolyte
of 40 % potassium hydroxide (KOH).
1.2 The values stated in SI units are to be regarded as the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1711 Terminology Relating to Electrical Insulation
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2935 Practice for Conducting Equivalence Testing in Laboratory Applications
2.2 Battery Council International:
Standard Test Method for Determining the Electrical Resistance of a Battery Separator Using a Palico Measuring
System, Section 3.3b
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 barrier resistance (RB), n—the resistance of the bath with a solid, nonporous sheet of alkaline resistant, electrical
insulation that separates the electrodes.
3.1.2 bath resistance (RC), n—the resistance of the bath without the specimen (separator).
3.1.3 bath resistance (RT), n—the total electrical resistance of the bath and a separator specimen.
3.1.4 battery separator, n—an ion-permeable, nonconductive material that prevents electrical contact between electrodes of
opposite polarity.
3.1.5 electrolyte, n—a 40 % potassium hydroxide solution.
3.1.6 ionic resisitivity (ER), n—the product of a change in electrical resistance times an area.
This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of Subcommittee
D09.01 on Electrical Insulating Products.
Current edition approved March 1, 2019Nov. 1, 2019. Published March 2019Nvember 2019. Last previous edition approved in 20132019 as D7148 – 13.D7148 – 19. DOI:
10.1520/D7148-19.10.1520/D7148-19A.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Battery Council International, 330 N. Wabash Ave., Ste. 2000, Chicago, IL 60611.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7148 − 19a
3.1.6.1 Discussion—
The area is the aperture area divided by the number of separators between the electrodes. The change in resistance is the difference,
in ohms, of the electrical resistance with and without the seperator(s). The SI units for ER are ohms-metre but the customary
practice in the battery industry is to report the ER in units of ohms-cm . This terminology is not in conflict with Terminology
D1711.
3.2 Symbols:
3.2.1 ER—a symbol, peculiar to the battery industry, denoting that characteristic of a sheet material that is related to the rate
of transfer of ions through the interstices of a porous sheet immersed between two carbon electrodes in an aqueous electroyte.
4. Summary of Test Method
4.1 This test method detects small changes in ohmic resistance between carbon electrodes immersed in an alkaline electrolyte
with and without separator material between the carbon electrodes. This change is related to the rate of transfer of ions through
a separator material. The ER is calculated from the fixed aperture area. The sensitivity and resolution of the apparatus detects
electrical resistance changes of 60.1 %.
5. Significance and Use
5.1 The ER of a battery separator is a standard measurement used by separator and battery manufacturers for quality control
purposes and separator selection.
5.2 Separator ER and the separator’s interaction with the electrolyte, that is resistance to wetting or flow, will contribute to the
internal resistance of the battery and this has the potential to limit the electrical output of a battery. The ER determination is a tool
for battery manufacturers to use in design, material selection, and performance specifications.
5.3 The change in the bath electrical resistance imparted by a separator is affected by the porosity, thickness, and tortuousity
of the pore structure of the separator, the wettability of the separator to the electrolyte, and the temperature and concentration of
the electrolyte.
5.4 Incomplete wetting or saturation of the pore structure limits the lowest ER value obtainable from a separator structure.
Separators are pretreated to assure that the specimen being tested has been adequately wetted out. A separator that is not fully
wetted out (saturated) will give a higher ER.
5.5 This test method is intended to give a rapid and repeatable measurement that approximates the change in ER that could
happen when the separator is used in a battery.
6. Apparatus
6.1 Stainless steel container or equivalent to accommodate the separator test samples.
6.2 Hot plate or other heating device suitable to boil water.
6.3 Stainless steel screen.
6.4 Glass or plastic separator tank for presoaking separators in battery electrolyte.
6.5 Interval timer.
6.6 Safety glasses.
6.7 Thermometer.
6.8 Alkaline resistant gloves, that is neoprene latex or polyethylene gloves.
6.9 Plastic tongs for handling KOH-wetted separators.
6.10 ER bath with a fixed aperture area (32 cm is standard) that puts a uniform current flux through a fixed area of the separator
sample for measurement. A drawing of an ER bath is included in Annex A1.
6.11 A.C. resistance meter or bridge with sufficient sensitivity and resolution to measure 60.1 % change in the ER bath
resistance in the presence of potentials generated in the ER bath.
7. Reagents and Materials
7.1 Distilled or deionized water.
7.2 Reagent grade KOH.
8. Hazards
8.1 Safety goggles and face shield, lab coat, and rubber apron and gloves must be worn during KOH dilution operations.
Enclose the glass-mixing bottle in a plastic container of sufficient capacity to contain the solution in case of bottle breakage. To
D7148 − 19a
prevent excessive heating, add concentrated KOH slowly to water with adequate agitation to produce thorough mixing. The diluted
KOH is sufficiently corrosive at both ambient and elevated temperatures that careful handling is necessary to prevent injury or
damage.
8.2 The hazard associated with mixing KOH with water is that it generates a lot of heat as it dissolves; this has the potential
to lead to spattering. A concentrated KOH solution will erode skin and eyes. Avoid these hazards by wearing safety glasses, face
shield, and protective gloves, and immediately rinsing with water if any skin contact occurs. (If any eye contact occurs, flush the
eyes with water for 15 min and then get medical attention.)
9. Sampling, Test Specimens, and Test Units
9.1 Select samples representative of the separator material to be tested.
9.2 Use a specimen size of at least 120 by 120 mm and no larger than what will fit in the bath.
9.3 If specimens require identification, use an alkaline resistant marker. Mark an area of the specimen that will not interfere with
the ion transfer through the separator.
10. Preparation of Apparatus
10.1 Fill the ER bath with prepared battery electrolyte (40 6 1 % KOH solution) to a level above the aperture opening (12 to
25 mm below the top of the ER bath). Adjust the bath’s temperature to 25 6 5°C .
10.2 Connect the electrodes to the resistance meter control unit using alkali-resistant wire and hardware.
10.3 Turn on the resistance meter. Allow the equipment to stabilize for at least 20 min. If the meter includes a standard reference
resistor (place in “Standby” mode and “Standard” scaling on the resistance meter control unit and set to the appropriate resistance
range scale for a 0.200-Ω0.14-Ω resistor reading). Unless the meter reading is within 60.1 % of the value of the resistor, service
will be required.
10.4 If available, check the resistance standard for the system outlined in 11.4. If this agrees within 61 %, proceed to Section
13.
10.5 Periodically, or when problems occur or changes are made to the system, test the stability, polarization, current leakage,
and standardization using the maintenance procedures set forth in Section 11.
11. Testing and Maintenance of Equipment
11.1 Stability of Equipment:
11.1.1 Check the resistance of the ER bath. (Place the meter in “Operate” mode and “Standard” scaling and press “Reset.” Set
the appropriate resistance range to give the maximum meter reading without going off scale.)
11.1.2 Agitate the electrolyte to make certain that the temperature and concentration are uniform.
11.1.3 Ensure the bath resistance (RC) is constant within 60.5 % at a given temperature and electrolyte concentration.
11.1.4 If readings are inconsistent, proceed to 11.2 and 11.3 for polarization and leakage determination.
11.2 Polarization of Equipment:
11.2.1 Polarization affects the reading of any resistance measuring system differently. Follow manufacturer instructions.
11.2.2 For the resistance measuring system, place the resistance unit in “Operate” mode and “Standard” scaling and press
“Reset.”
11.2.3 Set the appropriate resistance range to give the maximum meter reading (RC) without going over scale.
11.2.4 Press “Test Offset.” If the reading is higher than midrange of the set value then the polarization is too high.
11.2.5 If the polarization is above the maximum, allow 30 min for stabilization or discharge, or both. Then repeat measurement.
11.2.6 If the polarization persists, change the electrolyte and clean the electrodes.
11.3 Leakage Current:
11.3.1 Leakage currents potentially e
...