Plate Curing
1. Definition
A controlled temperature and humidity process that transforms soft, mechanically weak pasted plates into hard, porous, electrochemically active battery plates. Curing converts free lead in the paste to lead oxide, forms the crystal structure (tribasic lead sulfate), and creates a strong bond between the paste and the grid. Improper curing is the #1 cause of premature battery failure.
2. Process
1. Curing Chamber Loading
Pasted plates are stacked in racks with uniform spacing for airflow. Plates are loaded into multi-zone curing chambers capable of precise temperature (35-85degC) and humidity (95%+ RH) control.
2. Curing Phases (24-72 hours total)
Phase A — High Humidity (6-12 hrs): 35-45degC, 95-98% RH. Free lead oxidizes to PbO. This exothermic reaction generates heat — chamber temperature must be carefully controlled to prevent thermal runaway. Phase B — Crystal Growth (12-24 hrs): 50-65degC, 90-95% RH. Tribasic lead sulfate (3BS) crystals nucleate and grow on the grid surface. 3BS crystal structure provides high initial capacity. Phase C — Drying (6-12 hrs): 65-85degC, gradually decreasing RH to <10%. Removes residual moisture. Plates develop their characteristic chocolate-brown color.
3. Cured Plate Testing
Free lead content: Must be <2% (XRF or wet chemistry). Crystal structure: 3BS confirmed by XRD (X-ray diffraction) or SEM (scanning electron microscopy). Plate strength: Drop test from 1m — no paste shedding. Moisture content: <0.5%.
4. 4BS Option (Heavy Duty Batteries)
For heavy-duty batteries (145G51, 190H52), a higher-temperature cure (70-85degC) promotes tetrabasic lead sulfate (4BS) crystal formation. 4BS provides superior mechanical strength and cycling durability at the cost of slightly lower initial capacity. Chengguang uses 3BS for SLI batteries and 4BS for heavy-duty batteries.
3. Quality Control at Chengguang
Free lead content (<2% by XRF), crystal structure (3BS or 4BS per battery type), plate strength (drop test — no shedding), moisture content (<0.5%), visual (uniform color, no cracking). Chengguang operates multi-zone curing chambers with automated temperature/humidity profiling.
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