Technical manual section 03b

BCI Battery Technical Manual BCIS-03B REV DEC02 Issued Current Revision: 1992-03 2002-12 BCI RECOMMENDED MATERIALS SPECIFICATIONS BATTERY SEPARATOR TEST METHODS TABLE OF CONTENTS 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Standard Test Method for Overall Thickness of Battery Separator Standard Test Method for Overall Thickness of Battery Separator Including Attached Retainer Mat Standard Test Method for Backweb Thickness of Battery Separator Standard Test Method to Determine Squareness of Battery Separator Standard Procedure to Determine Height and Width of Battery Separators 11 Standard Test Method to Determine the Skew of Roll Stock Battery Separator Material 14 Standard Test Method to Determine Volume Porosity and Moisture Content of Battery Separators 16 Standard Test Method for Pore Size Characteristics by the Mercury Intrusion Method for Microporous Separators 18 Standard Procedure for Dimensional Stability of Separators in Group Formation Dry and Wet Charge Batteries 21 Standard Procedure for Dimensional Stability of Separators to Air Drying 23 Standard Test Method for Elongation and Tensile Strength of Microporous Polyethylene Battery Separator 25 Standard Test Method for Taber Stiffness of Leaf Separators 29 Standard Test Method to Determine Pin Puncture Resistance of Battery Separator Using a Manual Chatillon Tester 32 Standard Test Method to Determine Puncture Resistance of Battery Separators Using a Tensile (Instron®) Machine .35 Test VIII - Wetting Properties Procedure VIIIA - Acid Floatation Method 37 Test VIII - Wetting Properties Procedure VIIIB - Acid Drop Absorption Method 39 Test VIII - Re-Wetting Properties Procedure VIIIC - Dry Charge Process Simulation 41 Standard Test Method for Determining the Electrical Resistance of Battery Separator Using a PalicoMeasuring System 43 Standard Procedure for Separator Degradation Testing 51 Standard Test Method for Acid Extraction by Acid Reflux Procedure A-1 52 Standard Test Method for Hot Acid Soak Procedure A-2 54 Standard Test Method for Metal Analysis by Inductively Coupled Plasma Emission (ICP) Procedure C-2 56 Standard Test Method for Atomic Absorption Spectrophotometer (AA) Procedure C-1 63 Standard Test Method for Total Organic Carbon (TOC) Procedure D-1 64 Standard Method for Chloride Analysis in Sulfuric Acid by Atomic Absorption Spectrophotometer (AAS) 67 BCIS-03B Rev DEC02 26 27 28 29 30 31 32 33 34 Standard Test Method to Determine Chlorides in Sulfuric Acid by Turbidimetry 71 Standard Procedure to Determine Chlorides by Ion Specific Electrode 74 Standard Test Method to Determine Pin Puncture Resistance of Battery Separator Using a Motorized Chatillon Tester 78 Standard Test Method to Determine Resistance of Battery Separators to Oxidative Degradation Using Hydrogen Peroxide in Sulfuric Acid as Oxidizing Medium 80 Standard Test Method to Determine Resistance of Battery Separators to Hold Sulfuric Acid 85 Standard Test Method to Determine Resistance of Battery Separators to Oxidative Degradation Using Potassium Dichromate in Sulfuric Acid as Oxidizing Medium 89 Standard Test Method to Determine Reistance of Battery Separators to Oxidative Degradation Using Simulated Electrochemical Cell Environment as Oxidizing Medium 95 Standard Test Method to Determine Elemental Chlorine in Sulfuric Acid Solutions by Inductively Coupled Argon Plasma Optical Emission Spectroscopy (ICP/OES) 100 Standard Test Method to Determine Chlorides by Potentiometric Chloride Determination in Aqueous Extracts 104 BCIS-03B Rev DEC02 STANDARD TEST METHOD FOR OVERALL THICKNESS OF BATTERY SEPARATOR 1.1 SCOPE 1.1.1 This procedure provides a method of measuring the overall thickness of a battery separator using three different pressures depending on the application and type of separator 1.1.2 This procedure should not be used for separators with a retainer mat or with recombinant battery separator mat (RBSM) 1.2 SIGNIFICANCE AND USE 1.2.1 Accurate measurement and control of overall thickness of battery separators are essential to ensure correct assembly, and acceptable performance and life characteristics of the battery 1.2.2 The variety of separators and their end uses requires that three methods of measurement are available 1.2.3 Ribbed, corrugated, or embossed separators intended for SLI and most stationary applications are tested at 2.1 kPa (0.3 psi) See section 1.3.1 1.2.4 Separators intended for motive power and heavy duty stationary applications are generally thicker and stiffer They are best measured at a higher pressure See Subsections 1.3.2 and 1.3.3 1.3 APPARATUS 1.3.1 TYPE A - A gauge equipped with a 50 mm (2 in), diameter upper contact foot that exerts a pressure of 2.1 kPa (0.3 psi) on the full area of the anvil The anvil to be equal to or larger than the upper contact foot Dial graduation of the gauge is either 0.01 mm or 0.0001 in Examples are Ames's Dial Micrometer Model 262 with base Model #16, and Emveco's Microgauge Model 200A or equivalent 1.3.2 TYPE B - A gauge equipped with a 76 mm x 76 mm (3 in x in) upper contact foot that exerts a pressure of 6.9 kPa (1.0 psi) on the full area of the anvil Dial graduation of the gauge is either 0.01 mm or 0.0001 in e.g Amerace gauge, figure 1, or equivalent 1.3.3 TYPE C - A gauge equipped with a 76 mm x 76 mm (3 in x in) upper contact foot that exerts a pressure of 3.45 kPa (0.5 psi) on the full area of the anvil This gauge is equivalent to TYPE B except that the loading is only at 3.45 kPa 1.4 CALIBRATION 1.4.1 Make sure that the lower anvil and upper contact foot are clean, and operating smoothly without binding Check to ensure that the anvil is parallel with the contact foot, making uniform contact when they are closed This is done by using a gauge block and checking the reading obtained at a minimum of three spots 1.4.2 Check micrometer accuracy using certified gauge blocks Be sure the dial micrometer is zeroed when anvil and foot are in contact without the sample To adjust the gauge, check the manufacture’s instructions BCIS-03B Rev DEC02 1.5 PROCEDURE 1.5.1 Raise the foot and insert the separator sample, major rib-side up on the anvil 1.5.2 Gently lower the contact foot until it contacts the ribs The upper foot should not extend beyond the last rib of the separator by more than mm (0.24 in) Do not allow the foot to free fall or be spring driven onto the separator Take a minimum of three (3) readings 1.5.3 Measure the separator at each side and in the center Read the thickness to the nearest limiting decimal point of the gauge Record all numbers and location of measurements 1.6 REPORT 1.6.1 Report all readings of overall thickness per customer/ vendor requirements 1.6.2 Report apparatus type used BCIS-03B Rev DEC02 STANDARD TEST METHOD FOR OVERALL THICKNESS OF BATTERY SEPARATOR INCLUDING ATTACHED RETAINER MAT 2.1 SCOPE 2.1.1 This procedure provides a method of measuring the overall thickness of a battery separator with attached retainer mat The retainer mat is usually a glass mat 2.2 SIGNIFICANCE AND USE 2.2.1 Some batteries use separators with a retainer mat attached, usually to their major ribbed side The purpose of the retainer mat, positioned facing against the positive plate in the battery, is to reduce shedding of positive active material during the service of a battery 2.2.2 Unlike most rigid battery separators, the retainer mat is compressible under low pressure similar to Recombinant Battery Separator Mat (RBSM) The measured thickness of a retainer mat or a separator with a retainer mat attached depends on the pressure applied by the thickness gauge Therefore, the accuracy and value obtained for thickness of a separator with a retainer mat attached depends on the pressure applied by the thickness gauge 2.2.3 The ideal pressure of the thickness gauge may be the one that will simulate the pressure the element exerts on the glass mat in the cell Since the pressure varies depending on the intended battery design, the purpose of this procedure is to provide a standard method that should be universally acceptable for most battery assemblies and designs 2.2.4 The compressibility of a retainer mat attached to a separator varies depending on the configuration and area of separator ribs against which a glass mat is compressed The measured thickness of a separator / retainer mat assembly may not necessarily be the same as the sum of individually measured thickness of a separator and a retainer mat 2.2.5 With this method one may specify the thickness of a separator / retainer mat assembly, specify the thickness of a retainer mat, or thickness of a separator to which retainer mat will be attached 2.3 APPARATUS 2.3.1 A precision deadweight micrometer with a 50 mm (2 in) diameter upper contact foot and anvil, exerting a pressure of 3.0 kPa (0.435 psi) Two models are TMI’s No 553M and Ames No 24, or comparable gauge with 3.0 kPa spring tension with suitable loads and anvil sizes Dial graduation of the gauges is either 0.01 mm or 0.0001 in 2.4 CALIBRATION 2.4.1 Make sure that the lower anvil and upper contact foot are clean and operating smoothly without binding Check to ensure that the anvil is parallel with the contact foot making uniform contact when they are closed 2.4.2 Check the accuracy of the micrometer using certified gauge blocks Make sure that the dial micrometer is zeroed when the anvil and the foot are in contact without the sample To adjust the gauge, check the manufacturer’s instructions 2.4.3 The load applied to the anvil should be checked with a load cell or other suitable force measurement device 2.5 PROCEDURE BCIS-03B Rev DEC02 2.5.1 Raise the contact foot and insert the retainer mat or separator / retainer mat or assembly, retainer mat side up on the anvil 2.5.2 Gently lower the contact foot until it contacts the sample The upper contact foot should not extend beyond the last rib of the separator by more than mm (0.24in) Do not allow the foot to free-fall or be spring driven onto the sample backweb Take a minimum of three (3) readings Measure the separator at each side and in the center 2.5.3 Record all readings and locations measured 2.6 REPORT 2.6.1 Report all readings and overall thickness per customer/vendor requirements 2.6.2 Report the gauge, anvil size, loading of the gauge and what was measured BCIS-03B Rev DEC02 STANDARD TEST METHOD FOR BACKWEB THICKNESS OF BATTERY SEPARATOR 3.1 SCOPE 3.1.1 This procedure describes the general method for measuring backweb thickness between major ribs of various battery separators 3.2 SIGNIFICANCE AND USE 3.2.1 Accurate measurement and control of backweb are essential to ensure performance and life characteristics of the battery 3.2.2 The true backweb excludes the height of the mini-ribs However, for separators that have mini-ribs on either side of the backweb, those ribs may be included in the backweb reading If mini-ribs are included in the backweb thickness, then this fact should be noted 3.2.3 The wide variations in separator materials (degrees of web compressibility, rib pitch, composition, etc.) dictate the use of different micrometer types (see Apparatus) 3.3 APPARATUS 3.3.1 The gauge with a circular upper contact foot of 9.5mm (0.374 in.) in diameter that exerts a pressure of 2.1 kPa (0.3 psi) on the sample Gauge graduation must have at least 0.01mm (for metric) or 0.001 in (for English) resolution 3.3.2 Fibrous separators that are compressible, such as paper and non-wovens made from such material as cellulose, glass fiber and synthetic wood pulp and that have rib pitch values of 10mm (0.4 in.) or more, should be measured with this gauge 3.3.3 This method should not be used for recombinant battery separator mat (RBSM) 3.3.4 A gauge with a suitable contact foot and load so that pressure is exerted on the separator to equal 110 kPa ± 20 kPa (16 psi ± 2.9 psi) The gauge graduation must have at least 0.001mm (for metric) or 0.0001 in (for English) resolution 3.3.5 Non-fibrous, non-compressible separators, such as polyethylene, PVC, microporous rubber and other non-fibrous type separators should use this type of gauge 3.4 TERMINOLOGY 3.4.1 MINI-RIBS - Another name for smaller ribs located either on the seal shoulder or on either side of the backweb, between or opposite the major ribs 3.4.2 NEGATIVE'S MINI-RIBS - Separators that have mini-ribs on the backside This is the side that normally faces the negative plate 3.4.3 SHOULDER - This is the margin between either side edge of the separator and the adjacent major rib 3.4.4 SHOULDER MINI-RIBS - The ribs in the area of the shoulders 3.4.5 MAJOR RIBS - The ribs that normally face the positive plate These ribs are normally the tallest ribs 3.5 CALIBRATION BCIS-03B Rev DEC02 3.5.1 Make sure that the lower anvil and upper contact foot are clean and operating smoothly without binding Check to ensure that the anvil is parallel with the contact foot, making uniform contact when they are closed This is done by using a gauge block and checking the reading obtained at a minimum of three spots 3.5.2 Check micrometer accuracy using certified gauge blocks Be sure the dial micrometer is zeroed when anvil and foot are in contact without a sample To adjust gauge, check manufacturer's instructions 3.6 PROCEDURE 3.6.1 Raise the foot and insert the separator sample, rib-side up on the base plate 3.6.2 Center the measurement foot between ribs 3.6.3 Gently lower the contact foot down between the ribs until it contacts the backweb area Do not allow the foot to free fall, be spring driven onto the separator, or impinge on the radius base corner of the rib 3.6.4 Measure the backweb thickness of the separator at each side and in the center Read the thickness to the nearest limiting decimal point of the gauge 3.7 REPORT 3.7.1 Report all readings per customers / vendor requirements 3.7.2 Fibrous - nearest 0.1mm or 0.001 in 3.7.3 Non-Fibrous - nearest 0.01mm or 0.0001 in 3.7.4 The presence of mini-ribs that are included in the backweb thickness 3.7.5 The gauge used and the loading of this gauge BCIS-03B Rev DEC02 STANDARD TEST METHOD TO DETERMINE SQUARENESS OF BATTERY SEPARATOR 4.1 SCOPE 4.1.1 This procedure provides a method of measuring the squareness of sheet or leaf battery separator 4.2 SIGNIFICANCE AND USE 4.2.1 A sheet or leaf separator which is not square will result in difficulty during the battery assembly process and risk premature battery failure 4.3 APPARATUS 4.3.1 Square rule or squareness set-up plate which consists of a flat surfaced plate with locating bars positioned at right angle ( the vertical and horizontal members) 4.3.2 Steel rule graduated in a 0.5 mm or 1/64 in increments 4.4 TERMINOLOGY 4.4.1 The squareness of a separator is a linear measure of the deviation from exact squareness that two adjacent sides exhibit If those two sides form an exact 90 degree angle, the squareness value is zero 4.5 PROCEDURE 4.5.1 Place the separator to be checked on working surface of the apparatus of choice with "higher rib side" up 4.5.2 Place the side edge of separator against vertical member of the apparatus The side edge is that parallel to the ribs 4.5.3 Gently slide the separator toward the horizontal member until the end edge of the separator or some portion of the end edge of the separator, first makes contact with horizontal member, all the while keeping the side edge of separator against vertical member 4.5.4 Using the steel rule measure the squareness of the separator as the furthest distance (widest edge) between side edge and the end edge of the separator Record squareness to the nearest 0.5 mm or 1/64 in 4.5.5 Repeat above procedure after rotating separator 180 degrees 4.5.6 Steps 4.5.1 to 4.5.5 yields a squareness value for the end of the separator (Width) and is called end squareness By performing steps 4.5.1 to 4.5.5 with the separator rotated 90 degrees so that the end edge is placed against the vertical member and the side edge contacts the horizontal member, the squareness value for the side of the separator (height or length) can be determined This value is called side squareness and may be of greater significance where especially long separators are used (e.g., industrial cells) 4.6 REPORT 4.6.1 Report side squareness in mm (in) 4.6.2 Record width and height of the separator in mm (in) BCIS-03B Rev DEC02 4.6.3 The value can also be reported as mm/ mm of width for end squareness or mm/mm of height for side squareness 10 BCIS-03B Rev DEC02 31.9.3 Place the specimens in oven and dry for one hour at 70°C ± 2°C (158°F ± 3.6°F) 31.9.4 Remove the specimens from drying oven and place in the desiccator for cooling Weigh the specimens as rapidly as possible to the nearest 0.001 g using a laboratory balance Note initial weight Wi 31.9.5 Fill the appropriate size wide mouth glass reagent bottle, containing a ground glass stopper (e.g 500 or 1000 ml bottle) with oxidizing solution Use 150 ml of oxidizing solution for each gram of sample 31.9.6 Place the bottle into an oven and heat it until temperature of oxidizing solution reaches 80°C ± 2°C (176°F ± 3.6°F) 31.9.7 Introduce samples into the wide mouth, reagent glass bottle Make certain that the samples are immersed under oxidizing solution by using glass rods or other chemically inert material allowing separation of samples and circulation of oxidizing solution and heat Close the bottle with ground glass stopper 31.9.8 Heat the bottle with the samples immersed in the oxidizing solution for hours Maintain the solution temperature at 80°C ± 2°C (176°F ± 3.6°F) NOTE: The recommended time of exposure is three hours It is recognized that to obtain meaningful results a different time may be selected (or a different concentration of reagent), depending on the type and dimensions of materials being tested If a different time or reagent concentration is used, these changes should be so noted when the data is reported 31.9.9 Remove the samples from beaker and rinse them gently with water 31.9.10 Place the sample into a clean 600 ml beaker and add approximately 500 ml of fresh water and allow to soak at least for one hour to ensure that no residual oxidizing solution will remain in the pores of separator material 31.9.11 Gently and thoroughly rinse the sample again with water 31.9.12 Remove the sample from the rinse bottle Either air-dry the sample or remove excess water with a paper towel Use this step for Tensile Strength and Elongation Test (Subsection 31.10.2) and Puncture Resistance Test (Subsection 31.10.4) NOTE: The samples can still be corrosive and oxidize the jaws of the tensile or puncture tester 31.9.13 To determine Oxidative Weight loss (Subsection 31.10.1) dry the sample in an oven for 90 minutes at 70°C ± 2°C (158°F ± 3.6°F) and cool the sample in desiccator Weigh the sample as rapidly as possible after removing from desiccator Note final weight Wf 31.10 SAMPLE EVALUATION TESTS AND CALCULATIONS 31.10.1 Oxidation Weight Loss Test % Oxidation Weight Loss = ((Wi - Wf)/ Wi) x 100 Where Wi = Initial sample weight from Subsection 31.9.4 Wf = Final sample weight from Subsection 31.9.12 31.10.2 Tensile Strength and Elongation Test 92 BCIS-03B Rev DEC02 31.10.2.1 Perform tensile strength and elongation tests on control sample and oxidized sample Refer to Subsection 11: Standard Test Method for Elongation and Tensile Strength of Microporous Polyethylene Battery Separator 31.10.2.2 Record tensile strength of untreated control sample in MPa Note tensile strength of control sample A 31.10.2.3 Record tensile strength of oxidized sample in MPa Note tensile strength of oxidized sample B 31.10.2.4 % Retention of Tensile Strength = (B/ A) x 100 Where A = Tensile Strength of Control Sample from Subsection 31.10.2.2 B = Tensile Strength of Oxidized Sample from Subsection 31.10.2.3 31.10.2.5 Record elongation of untreated control sample in % Note elongation of control sample C 31.10.2.6 Record elongation of oxidized sample in % Note elongation of oxidized sample D 31.10.2.7 % Retention of Elongation = ((C - D)/ C) x 100 Where 31.10.3 C = Elongation of Control Sample from Subsection 31.10.2.5 D = Elongation of Oxidized Sample from Subsection 31.10.2.6 Puncture Resistance Test 31.10.3.1 Perform puncture resistance tests on control sample and oxidized sample Refer to Subsection 13: Standard Test Method to Determine Pin Puncture Resistance of Battery Separator Using a Manual Chatillon Tester, Subsection 28: Standard Test Method to Determine Puncture Resistance to Battery Separator Using an Automatic Chatillon Tester, or Subsection 14: Standard Test Method to Determine Puncture Resistance of Microporous Polyethylene, Rubber and PVC Battery Separator Using Tensile (Instron) Machine 31.10.3.2 Record puncture resistance force of untreated control sample in kg (or Newton) Note puncture resistance of control sample A 31.10.3.3 Record puncture resistance force of oxidized sample in kg (or Newton) Note puncture resistance of oxidized sample B 31.10.3.4 Report % Retention of Puncture Resistance = ((A - B)/ A) x 100 Where A = Puncture Resistance of Control Sample from Subsection 31.11.3.2 B = Puncture Resistance of Oxidized Sample from Subsection 31.11.3.3 31.10.4 Delamination of Glass Fiber Test 31.10.4.1 Proceed with accelerated oxidation test procedure Subsection 31.9.1 through Subsection 31.9.12 31.10.4.2 Remove the sample and visually inspect individual sample for blisters or other signs of delamination 31.11 REPORT 31.11.1 Oxidation Weight Loss Test 93 BCIS-03B Rev DEC02 31.11.1.1 Report % weight loss to nearest 0.1% 31.11.1.2 Report oxidative degradation test procedure used for the test 31.11.2 Tensile Strength and Elongation Test 31.11.2.1 Report tensile and elongation test procedure used 31.11.2.2 Report tensile strength MPa and elongation in % of untreated control sample and oxidized sample Report backweb thickness of sample 31.11.2.3 Report % retention of elongation and tensile strength 31.11.3 Puncture Resistance Test 31.11.3.1 Report puncture tester and puncture resistance test procedure used 31.11.3.2 Report puncture resistance of untreated control sample and oxidized sample Report backweb thickness of sample 31.11.3.3 Report % retention of puncture resistance 31.11.4 Delamination of Glass Fiber Test 31.11.4.1 Report presence of blisters or other signs of fiber delamination after visual inspection 31.12 PRECISION AND BIAS 31.12.1 Precision 31.12.1.1 A round robin test study conducted with very limited number of tests on polyethylene separators and hard rubber separators showed very wide variations of test results among testing laboratories 31.12.1.2 No statement on repeatability (within a laboratory), comparability (between materials) or reproducibility (between laboratories) can be made due to lack of sufficient test data 31.12.2 Bias 31.12.2.1 No statement on bias can be made due to lack of a standard reference material 94 BCIS-03B Rev DEC02 32 STANDARD TEST METHOD TO DETERMINE RESISTANCE OF BATTERY SEPARATORS TO OXIDATIVE DEGRADATION USING SIMULATED ELECTROCHEMICAL CELL ENVIRONMENT AS OXIDIZING MEDIUM 32.1 SCOPE 32.1.1 This test procedure provides a test method to determine resistance of separator material to oxidative degradation by simulated electrochemical cell environment as oxidizing medium 32.1.2 This test procedure is intended to simulate the resistance of separators to oxidative degradation in lead-acid batteries at an accelerated rate 32.1.2.1 If used for quality control (comparative) purposes the test can be terminated after a prescribe time, e.g 50 or l00 h 32.1.2.2 If used for initial evaluation and acceptance purposes, the test should be continued until failure (Subsection 32.9.6) 32.1.3 Procedure is one of the four test methods made available by BCI that require exposure of separators to various corrosive environments which include: 32.1.3.1 Heated sulfuric acid 32.1.3.2 Hydrogen peroxide in sulfuric acid 32.1.3.3 Potassium dichromate in sulfuric acid 32.1.3.4 Simulated electrochemical oxidative conditions in battery cell under charging 32.2 REFERENCE DOCUMENTS 32.2.1 BCIS-03B Subsection 29, “Standard Test Method to Determine Resistance of Battery Separators to Oxidative Degradation Using Hydrogen Peroxide in Sulfuric acid as Oxidizing Medium.” 32.2.2 BCIS-03B Subsection 30,”Standard Test Method to Determine Resistance of BatterySeparators to Corrosive Degradation Using Hot Sulfuric Acid as Corrosion Medium.” 32.2.3 BCIS-03B Subsection 31, “Standard Test Method to Determine Resistance of Battery Separators to Oxidative Degradation Using Potassium Dichromate In Sulfuric Acid As Oxidizing Medium.” 32.3 SIGNIFICANCE AND USE 32.3.1 Battery separators are exposed to distinctive physical and chemical degradation in battery service Significant variations in temperature, electrolyte concentration, overcharge, chemical impurities, physical stresses and service duration are not uncommon Failure modes of separators due to physical or chemical degradation are generally unique to the type of separator, battery design construction and type of battery service Tests to accelerate degradation through high temperatures and corrosive chemicals or electrochemical treatments can often lead to failure modes not representative of and/or disproportional to physical service life 32.3.2 Due to conditions described above, there may not be one definitive test that will adequately define separator degradation 95 BCIS-03B Rev DEC02 32.3.3 It is the responsibility of battery producer and separator manufacturer to jointly agree on test method(s) that will accelerate degradation modes normally seen in the service of a particular type of battery and separator 32.3.4 Adoption of proper degradation resistance test methods for a particular type of battery separator should be determined by the similarity between the test method and actual degradation mode of the separator in the applicable battery cells during the service 32.3.5 This test procedure, in general, can be used as qualification testing, verification testing or validation testing of separator materials 32.4 SAFETY 32.4.1 Read and comprehend the sulfuric acid, safety data sheets and your company’s safety procedure Safety goggles, lab coats and rubber apron must be worn during acid dilution operations The glass mixing bottle should be enclosed in a plastic container of sufficient capacity to contain the solution in case of bottle breakage To prevent excessive heating, concentrated sulfuric acid should be added slowly to water with adequate agitation to produce thorough mixing The diluted acid is sufficiently corrosive at both ambient and elevated temperatures that careful handling is necessary to prevent injury or damage 32.4.2 32.4.3 Test cells may explode since the sulfuric acid in the cell produces an explosive mixture of hydrogen and oxygen Extreme caution should be taken to make sure that the test cells are stored, and worked on, in a well-ventilated area Always wear safety glasses and a face shield when working on or near the test cells Keep all sparks, flames and cigarettes away from the test cells 32.4.4 Follow current Federal, State, and Local regulations for the safe disposal of all chemicals used, including sulfuric acid 32.5 APPARATUS 32.5.1 The assembly of electrochemical test apparatus including electric circuits is shown in figure 32.5.2 Lead Plates 32.5.2.1 Electrodes for both anode and cathode are fabricated by cutting a mm thick lead plate as shown in Figure 35.2 Thicker lead plates can be used A thickness of mm, is the minimum that is recommended 32.5.2.2 Dimension of an electrode for effective testing area is 50 mm x 50 mm 32.5.2.3 The surface of the electrode facing the separator must be clean (free of oxide) smooth and flat 32.5.2.4 The electrode should be replaced with a fresh electrode after each test 32.5.3 Polyethylene or Polypropylene cable ties 32.5.4 Lead wire and connecting hardware made of type 316 stainless steel 32.5.5 Glass plate, 75mm high x 75mm wide x to 20 mm thick 32.5.6 Container, 200 mm high x 80 mm wide x 120 mm long or a battery container having a cell compartment 170 to 270 mm high x 35 to 85 mm wide x 120 to 190 mm long, e.g BCI Group 96 BCIS-03B Rev DEC02 Numbers 24 or 75 for 12 volt batteries, with compartments; or Group Numbers or C2 for volt batteries, with compartments 32.5.7 Container must be washed with water after each test or once a week 32.5.8 Bundle of separators and glass mats (battery retainer type or RBSM type) cut to 79 mm x 70 mm for shimming 32.5.9 Water bath equipped with thermostat capable of maintaining bath temperature at 50°C ± °C 32.5.10 Ammeter 32.5.11 Voltage recorder 32.5.12 DC stabilizing power supply 32.6 REAGENTS 32.6.1 Sulfuric acid, reagent ACS grade or battery grade, specific gravity 1.300 at 2O °C 32.6.2 Distilled water 32.7 PREPARATION OF SEPARATOR TEST 32.7.1 Specimen 32.7.1.1 Cut a separator to 70 mm by 70 mm 32.7.1.2 Leave ribs on any separator if the separator has ribs 32.7.1.3 Remove any glass mat from the separator if it has glass mat attached 32.8 PROCEDURE TO SET UP ASSEMBLY OF TEST EQUIPMENT 32.8.1 Prepare a separator test stack by placing glass plate, anode, separator sample, cathode, and glass plate in the order as shown in Figure 32.8.2 The entire stack must be centered, aligned and tied with Polyethylene cable ties as shown in Figure 32.3 97 BCIS-03B Rev DEC02 32.8.3 Build shimming material by stacking separator sheets and glass mats (flooded battery retainer type or valve regulated RBSM type) cut to 75 mm x 75 mm wide which consists of separators / glass mats / separators at approximately 40% / 20% / 40% of space between separator test stack and container wall respectively Sheets of glass mat, acting as a cushion, are inserted between bundles of rigid separators to provide adequate fit under compression for separator test stack 32.8.4 Insert the separator test stack in the middle and shimming stack on each end in a vertical position in the container as shown in Figure Make certain that adequate fit or compression is provided to the separator test stack by selecting the proper number of separator (s), and glass mat sheets used as the shim stock 32.8.5 Fill the test container with 1.300 (20°C) specific gravity sulfuric acid to a level 25 mm above the top of the test stack Allow the separator test stack to be wetted with the acid at least hours before starting the test This allows the test cell to be warmed up and separator test piece to be thoroughly wetted 98 BCIS-03B Rev DEC02 32.8.6 If a commercial battery container with multiple compartments is used, fill the unused compartments with 1.30 specific gravity sulfuric acid or water to provide appropriate heat transfer to the test cell 32.8.7 Place the test container in water bath with thermostat, (or air oven) which is capable of maintaining water temperature at 50°C ± 2°C 32.8.8 Maintain the temperature of test container and the bath at 50°C ± 2°C throughout the test period 32.9 PROCEDURE FOR ACCELERATED DEGRADATION TEST 32.9.1 Set up the test assembly as described in Subsection 32.88 and shown in Figure 32.3 32.9.2 After wiring as shown in Figure 32.1, turn on the power Adjust current to 2.5 A before commencement of testing 32.9.3 Set the voltage recorder paper so that one can see the timer easily 32.9.4 Start the test 32.9.5 Initial electrolyte level should be maintained by adding distilled water when the level decreases during the prolonged test period 32.9.6 Terminate the test when either the voltage fluctuates more than 0.2 V/minute or if a short circuit occurs Note time (in hours) and type of failure 32.10 REPORT 32.10.1 Report 32.10.1.1 If following the protocol in Subsection 32.1.2.1, report whether the material passed or failed and the length of time used 32.10.1.2 If following the protocol in Subsection 32.1.2.2, report the time to failure in hours and method (Subsection 32.9.6) 32.11 PRECISION AND BIAS 32.11.1 Precision 32.11.1.1 No statement on precision can be made 32.11.2 Bias 32.11.2.1 No statement on bias can be made due to a lack of standard reference material 99 BCIS-03B Rev DEC02 33 STANDARD TEST METHOD TO DETERMINE ELEMENTAL CHLORINE IN SULFURIC ACID SOLUTIONS BY INDUCTIVELY COUPLED ARGON PLASMA OPTICAL EMISSION SPECTROSCOPY (ICP/OES) 33.1 SCOPE 33.1.1 This procedure provides a method for determining the leachable elemental chlorine from battery separators by Inductively Coupled Argon Plasma Optical Emission Spectroscopy (ICP/OES) at a wavelength of 134.724 nm This low UV ICP emission spectrometer is specially designed for analysis of atomic line emissions down to 120.000 nm (ref 2.1, 2.2, 2.3, 2.4) The separator leach solution (ref 2.5, 2.6) is analyzed directly for chlorine along with other leachable elemental impurities No additional sample preparation is needed as required by other methods 33.1.2 Interference's such as bromide and Iodide not affect the ICP/OES analysis because the ICP/OES is measuring chloride directly and not a precipitate (ref 2.7, 2.8) Chloride concentrations can be measured down to 1.0 part per million (ppm) in solution by the ICP/OES method 33.1.3 The type of ICP/OES needed for this method is quite specific: Most units will not meet these requirements A unit must be able to read the atomic line spectra for chloride that is at 134.724 nm 33.2 REFERENCED DOCUMENTS 33.2.1 Spectro Analytical Instruments, News of the Americas, “New Spectro M120 ICP”, spring 1998 33.2.2 JY Emission Horiba Group, The SpectraLink, “Analysis of Chlorine in an Aqueous Matrix”, Vol 1, issue 1, September 1998 33.2.3 LaFreniere, B.R.; Houk, R.S.; Fassel, V.A Anal Chem 1987, 59, 2276-2282 33.2.4 Denton, M.B.; Pilon, M.J.; Babis, J.S., Appl Spectrosc 1990, 44, 975-978 33.2.5 BCI Standard Test Method for Acid Extraction By Acid Reflux, BCIS-03B Subsection 20 33.2.6 BCI Standard Test Method for Acid Extraction By Hot Acid Soak, BCIS-03B Subsection 21 33.2.7 BCI Standard Test Method for Chloride Analysis By Atomic Absorption Spectrophotometer (AAS), BCIS-03B Subsection 25 33.2.8 BCI Standard Test Method to Determine Chlorides in Sulfuric Acid By Turbidimetry, BCIS03B Subsection 26 33.3 SIGNIFICANCE AND USE 33.3.1 Soluble chloride in battery electrolyte can increase the rate of positive grid corrosion and can increase the solubility of active material in the electrolyte 33.4 APPARATUS 33.4.1 All reagents must conform to American Chemical Society (ACS) reagent grade specifications (chlorine free) 33.4.2 Purified water must be Type I, 18 MΩ•cm 100 BCIS-03B Rev DEC02 33.4.3 Matrix matched Calibration Standards made from chlorine free elemental stock solutions 33.4.4 Concentrated sulfuric acid (18 M) 33.4.5 Spectro’s M120 ICP, low UV ICP/OES (down to 120.000 nm) or equivalent instruments that can read down to 120.000 nm 33.4.6 Purified Water System 33.4.7 Pipettes, 0.05 to 10.0 mL 33.4.8 Class A, volumetric flasks, 10, 25, 50, 100, 1000 ml 33.4.9 Analytical balance with decimal place accuracy 33.5 SAFETY 33.5.1 The operator must be familiar with the Material Safety Data Sheets for all reagents used and follow company Standard Operating Procedures Always wear lab coats, safety glasses, and protective gloves (powder free) Know where safety showers and eyewash stations are in case of accidental contact Always wash hands thoroughly after reagent use 33.5.2 Always handle all reagents and prepare sample solutions in an acid fume hood 33.5.3 Sulfuric acid and water mixing can be a violent exothermic reaction if improper mixing takes place Always add sulfuric acid very slowly to water under agitation, and the solution will generate heat, but under controlled conditions It is important to agitate the dilution too avoid the possibility of a thermal gradient breaking the glass 33.5.4 Follow site disposal procedures for old samples and unwanted reagents 33.6 PREPARATION 33.6.1 No further preparation is needed for the resulting leached solution which is 1.265 g/mL sulfuric acid obtained by following BCIS-03B Subsection 20: Standard Test Method for Acid Extraction by Acid Reflux- Procedure A-1 or BCIS-03B Subsection 21: Standard Test Method for Hot Acid Soak-Procedure A-2 33.6.1.1 Either method can be used 33.6.1.2 The procedure used should be reported, either BCIS-03B Subsection 21 33.6.2 Prepare two to three matrix matched calibration standards from 1.000 μg/ml Cl to 50.00 μ g/ml Cl in 1.265 g/mL sulfuric acid 33.6.2.1 Failure to have exactly the same acid concentration in the standards as in the samples will lead to inaccurate results 33.6.3 If the calibration standards are made in sulfuric acid solutions other than 1.265 g/ml sulfuric acid solutions, then the leach sample solution must be diluted so that the resulting diluted leach sample solution matches the sulfuric acid concentration of the calibration standards Then an appropriate dilution factor is calculated and is used to obtain the original concentration in the 1.265 g/ml sulfuric acid leach solution Note: Failure to have exactly the same acid concentration in the standards as in the sample will lead to inaccurate results 101 BCIS-03B Rev DEC02 33.7 PROCEDURE 33.7.1 Calibrate low UV ICP/OES 33.7.2 Run samples directly using a dilution factor of 0.79 The dilution factor will convert the result from μg/mL to μg/g 33.7.3 If the original leach sample was diluted as described in Subsection 33.6.3, then the dilution factor for the μg/mL to μg/g conversion will be different and it will have to be determined by the user 33.8 CALCULATION 33.8.1 Calculations are done using the instrumental software and the results are reported as μg/g Cl in the sample Report the leaching procedure used Comparative Data for Chloride Analysis Table ICP/OES Turbidemetric No Test Period Low UV (mg/kg Cl) (9/98-11/98) method (mg/kg Cl) ('96 - '98) 51.1 49.0 53.1 49.0 53.7 50.4 50.4 49.0 49.9 45.1 45.4 46.6 45.3 46.5 47.4 47.6 44.2 47.3 average std.dev std dev 50.6 1.7 5.1 46.2 1.2 3.6 Theoretical % Difference 48.0 5.4 48.0 -3.8 102 BCIS-03B Rev DEC02 Note: Each of the above tests represent different samples Table ll Table II Supplemental Individual Data Points 1070 acid water soln #1 water soln #2 water soln #3 water soln #4 water soln #6 water soln #7 10.5 21.9 21.0 26.9 26.8 14.8