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IS 652:1960 is the Indian Standard (BIS) for wooden separators for lead-acid storage batteries. This standard specifies the physical, chemical, and electrical requirements for wooden separators used in lead-acid storage batteries. It details the selection of suitable timber species, necessary chemical treatments to remove harmful organic acids, and permissible tolerances to ensure proper electrical insulation and electrolyte permeability.
Wooden Separators for Lead-Acid Storage Batteries
Overview
Status
Current
Usage level
Rare
Domain
Materials Science — Wood and Other Lignocellulosic Products
! Wooden separators are virtually obsolete in modern battery manufacturing, having been entirely superseded by synthetic materials like microporous polyethylene (PE) and Absorbed Glass Mat (AGM).
! When referring to this code for historic restoration or specialized legacy applications, ensure the timber is thoroughly treated; untreated wood contains acetic acid which rapidly degrades lead plates.
woodtimberlead-acidseparatorselectrolyte
International Equivalents
Similar International Standards
SAE J2800:2016SAE International, USA
MediumCurrent
Materials for Lead-Acid Battery Separators
Covers modern separator materials (PE, AGM) for the same application, but not wood.
JIS C 2315:1990Japanese Industrial Standards, Japan
HighWithdrawn
Separators for lead-acid batteries
Directly addressed separators for lead-acid batteries, covering various materials of its time.
DIN 43557:1982Deutsches Institut für Normung, Germany
HighWithdrawn
Separators for lead-acid batteries; technical conditions of delivery
Specified technical requirements and delivery conditions for various types of battery separators.
IEC 60095-1:2018International Electrotechnical Commission, International
LowCurrent
Lead-acid starter batteries - Part 1: General requirements and methods of test
A battery system standard whose performance tests implicitly govern separator properties.
Key Differences
≠Material Specification: IS 652 is prescriptive, specifying wood types (Port Orford Cedar, Douglas Fir). Modern standards like SAE J2800 are performance-based and material-focused (PE, AGM), not prescribing specific sources.
≠Technology Focus: IS 652 is based on obsolete 1960s technology (treated wood). Modern equivalents focus on microporous polyethylene (PE) or absorbed glass mat (AGM) separators, which offer lower resistance and better performance.
≠Test Methodologies: IS 652 specifies older, often qualitative or manual test methods (e.g., visual comparison for manganese test). Current standards mandate sophisticated, instrument-based quantitative analysis for impurities and performance characteristics.
≠Separator Thickness: Wooden separators specified in IS 652 are very thick (1.5-3.0 mm), increasing internal resistance. Modern PE separators are much thinner (0.15-0.3 mm base web), improving power density.
Key Similarities
≈Core Function: Both IS 652 and its modern equivalents specify the separator's fundamental role: acting as an electronic insulator between plates while allowing ionic transport through the electrolyte.
≈Chemical Purity: All standards emphasize the need for high chemical purity. IS 652 explicitly limits harmful impurities like iron and manganese, a principle that remains critical in modern standards, albeit with stricter limits and broader scope.
≈Fundamental Parameters: Key parameters like electrical resistance, mechanical strength (resistance to puncture), and dimensional stability are central to both the old Indian standard and modern international ones.
≈Dimensional Control: IS 652 provides tolerances for length, width, and thickness. This focus on precise dimensions to ensure proper fit and prevent short circuits is a common feature in all separator standards.
Parameter Comparison
Parameter
IS Value
International
Source
Material Type
Prescribed wood types: Port Orford Cedar, Douglas Fir, Cypress
Microporous Polyethylene (PE) with silica filler, Absorbed Glass Mat (AGM)
SAE J2800:2016
Typical Thickness
1.5 mm to 3.0 mm
0.15 mm to 0.30 mm (base web thickness for PE)
SAE J2800:2016
Electrical Resistance (qualitative)
High (e.g., not to exceed 0.00065 ohm/cm²/mm)
Very Low (e.g., typically < 0.0001 ohm/cm² for a finished PE separator)
SAE J2800:2016
Iron Content (max)
0.02% by weight (200 ppm)
Much lower; typically < 20 ppm as a leachable impurity
JIS C 2315:1990 / Modern Practice
Manganese Content (max)
0.0005% by weight (5 ppm)
Typically < 0.5 ppm
JIS C 2315:1990 / Modern Practice
Porosity
Not explicitly defined; a result of wood structure and treatment
Defined and controlled; ~55% for PE, >90% for AGM
SAE J2800:2016
⚠ Verify details from original standards before use
Key Values0
No quick reference values available for this code yet.
Tables & Referenced Sections
Key Tables
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Key Clauses
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Frequently Asked Questions2
Why were wooden separators originally used in batteries?+
Wood is naturally porous, allowing battery electrolyte (acid) to flow between plates while providing a solid physical barrier that prevents positive and negative plates from short-circuiting.
What has replaced wooden separators in modern applications?+
Microporous polymers (like PE and PVC) and Absorbed Glass Mat (AGM) have replaced wood due to better chemical resistance, lower electrical resistance, and longer lifespan.