Battery Casting Shoe Passages for Flash-Free Grid Formation
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Solution Overview
Problem
Existing continuous casting machines for lead-acid battery grids face challenges in consistently producing high-quality grids at high speeds over long periods, including flashing of lead between drum grooves, incomplete filling of mold cavities, and cold welded seams, which affect structural quality and current carrying capacity.
Innovation Solution
A casting shoe with a longitudinally elongate orifice slot and separate molten lead supply and return passages, inclined to manage the flow of molten lead effectively, reducing upflow and ensuring complete filling and homogeneous casting, along with a return passage system that enhances the return of excess lead, improving the integrity of the cast grids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional casting shoe with a single orifice slot and supply passage is used, then the structure is simple, but lead flashes between drum grooves and mold cavities are not completely filled, producing poor grid quality
Solution Approach 1:
The casting shoe is segmented into multiple functional zones: a first orifice slot for supplying molten lead to the mold cavity, a second orifice slot for supplying lead to the groove, and separate supply passages for each. This segmentation allows independent control of lead flow to different areas, preventing flashing while ensuring complete filling, thereby improving grid quality without excessive complexity.
Solution Approach 2:
Different regions of the casting shoe are provided with different structures: the first orifice slot has a supply passage inclined downward toward the drum to facilitate complete filling of the mold cavity, while the second orifice slot has a separate supply passage to prevent lead flashing between grooves. This local differentiation addresses specific problems in specific areas, achieving high grid quality.
2Productivity
If the casting machine operates at high speed for long periods, then productivity increases, but cold welded seams and knitted joints occur, reducing current carrying capacity
Solution Approach 1:
The supply passages are designed to pre-heat the molten lead before it reaches the orifice slots through downward inclination, ensuring the lead maintains proper temperature and fluidity. This preliminary thermal preparation prevents cold welded seams and knitted joints even during high-speed continuous operation, maintaining joint integrity and current carrying capacity.
Solution Approach 2:
The casting shoe design ensures continuous, smooth flow of molten lead through separate supply passages to both the mold cavity and groove, preventing interruptions or turbulence that could cause cold welding. The downward inclination of supply passages promotes continuous laminar flow, ensuring reliable homogeneous casting and fused joints during prolonged high-speed operation.
3Productivity
If excess molten lead is not properly returned, then the process is simple, but dross accumulates and requires frequent removal, reducing productivity
Solution Approach 1:
A separate excess molten lead return passage is extracted from the casting shoe structure, distinct from the supply passages. This dedicated return passage efficiently collects and removes excess lead and dross from the casting area, preventing accumulation and enabling longer continuous operation without dross removal, thereby increasing productivity.
Solution Approach 2:
The return passage acts as an intermediary channel that separates the excess lead removal function from the molten lead supply function. This intermediary structure allows independent optimization of both supply and return flows, enabling continuous casting for longer periods by efficiently managing dross removal without complicating the overall system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables longer continuous casting without dross removal, increased production rate, improved grain structure, and enhanced lug integrity, allowing for higher quality and more efficient production of lead-acid battery grids.
Implementation Method 1
the supply passage may be inclined downwardly generally toward the direction of rotation of the drum past the orifice slot(s)
Implementation Method 2
the return passage(s) may be inclined generally downwardly away from the direction of rotation of the drum past the orifice slot(s)
Implementation Method 3
a homogeneously fused joint of the lug with the adjacent wire portions of the cast grid
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A shoe for dispensing a molten metal such as lead into a mold cavity of a rotating drum to continuously cast a web of a plurality of serially connected grids or battery composite electrodes of a carbon fiber material with a cast metal conductor. The shoe may have at least one elongate orifice slot in a face confronting the drum, a molten metal supply passage communicating with the orifice slot and an excess molten metal return slot opening into the confronting face downstream of the supply slot relative generally to the direction of rotation of the drum.