Grid Casting
1. Definition
Production of lead alloy grids — the metallic skeleton that conducts current and supports the active material in every lead-acid battery plate. Grid casting is the first and arguably most critical manufacturing step: grid alloy composition and casting quality determine the battery's corrosion resistance, mechanical strength, and electrical performance.
2. Process
1. Alloy Preparation
Pure lead (99.97%+) is melted in a kettle at 450-500degC. Alloying elements are added: Calcium (0.06-0.09%) for maintenance-free operation and low water loss, Tin (0.3-1.5%) for improved castability and corrosion resistance. For heavy-duty batteries: Antimony (1.5-3.0%) replaces calcium for mechanical strength and deep-cycle tolerance.
2. Gravity Casting (Chengguang Method)
Molten alloy at 480-520degC is poured into water-cooled cast-iron book molds. The mold closes, alloy fills the grid cavity, solidifies within 3-5 seconds, and the mold opens to eject the grid. Water cooling maintains mold temperature at 120-150degC for consistent solidification.
3. Alternative: Expanded Metal
Cast lead strip is slit and mechanically stretched into a diamond-mesh grid. Faster and cheaper than gravity casting, but with less design flexibility and poorer corrosion resistance. Chengguang uses gravity casting exclusively for automotive batteries.
4. Grid Trimming & Inspection
Excess flash is trimmed. Grids are visually inspected for: complete filling (no missing wires), uniform thickness, no cracks. Sample grids are weighed and measured. Defective grids are returned to the lead pot for remelting.
3. Quality Control at Chengguang
Grid wire thickness (1.2-4.0mm depending on battery type), grid weight (target +/- 2%), alloy composition (spectrometer verification per melt), dimensional check (length, width, lug position), visual inspection for casting defects. IATF 16949 requires alloy certification per heat lot with full traceability to the grid production batch.
4. Why Grid Quality Matters for OEM Buyers
Every manufacturing step directly impacts the battery you receive. When sourcing OEM batteries, ask your manufacturer about their grid alloy, paste formulation, curing profile, and formation process — these are the four factors that determine real-world battery life in your market. Chengguang's IATF 16949 certification guarantees documented, audited, and traceable manufacturing at every step.
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Author: Chengguang Power Tech Engineering Team | Reviewed: IATF 16949 Quality Department | Battery Database