Lead-acid Battery Negative Electrode Bushing Rib Design
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Solution Overview
Problem
Lead-acid batteries face electrolyte leakage issues due to the close proximity of the electrolyte solution to the negative electrode bushing, leading to corrosion and stress that causes cracks and leakage, especially in configurations aimed at improving volumetric efficiency.
Innovation Solution
A lead-acid battery design with a maximum gap of 0.5 mm to 2.5 mm between the negative electrode post and bushing, and a rib protrusion height of 1.5 mm to 4.0 mm, ensures the negative electrode terminal's structural integrity and prevents electrolyte leakage by allowing expansion and maintaining vibration resistance while avoiding excessive stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the electrolyte solution surface and the negative electrode bushing is reduced to improve volumetric efficiency, then the battery volume is reduced, but electrolyte leakage occurs at the end of battery life due to corrosion and stress
Solution Approach 1:
The patent applies local quality by providing a rib structure at a specific location (lower part) of the negative electrode bushing with different properties (protrusion height of 1.5-4.0 mm) than the rest of the bushing. This localized structural modification addresses the corrosion and stress concentration at the critical area where electrolyte contact occurs, without changing the overall battery volume configuration.
Solution Approach 2:
The rib structure serves as a preemptive protective measure against future corrosion and stress damage. By providing this structural reinforcement in advance (before corrosion occurs), the patent prevents electrolyte leakage that would otherwise happen at the end of battery life, allowing the electrolyte surface to be positioned closer to the bushing.
2Object-affected harmful factors
If the gap between the negative electrode post and negative electrode bushing is increased to prevent corrosion, then corrosion is reduced, but the structural integrity and vibration resistance deteriorate
Solution Approach 1:
The patent maintains a controlled gap (0.5-2.5 mm) between the negative electrode post and bushing to prevent corrosion, while simultaneously providing a rib structure at a critical location to maintain structural integrity. The rib's protrusion height (1.5-4.0 mm) compensates for the gap-induced weakness, creating a localized reinforcement that preserves overall strength without requiring a larger gap throughout.
Solution Approach 2:
The bushing structure is segmented by adding a rib feature that divides the wall structure into distinct regions. This segmentation allows different portions of the bushing to serve different functions: the gap region prevents corrosion while the rib region provides structural reinforcement and vibration resistance.
3Reliability
If the rib protrusion height is increased to prevent cracks and leakage, then reliability is improved, but the manufacturing complexity and stress concentration increase
Solution Approach 1:
The patent optimizes the rib protrusion height within a specific range (1.5-4.0 mm) to achieve the desired reliability without excessive complexity. This parameter optimization balances the competing requirements: sufficient protrusion height to prevent cracks and leakage, but not so high as to create excessive stress concentration or manufacturing difficulty. The gap width (0.5-2.5 mm) is also optimized within a specific range to achieve similar balance.
Data Source
AI summary
A lead-acid battery includes an electrode plate assembly, a battery case, a positive electrode strap, a negative electrode strap, a positive electrode post, a negative electrode post, a cover, and an electrolyte solution. A negative electrode bushing provided in the cover and the negative electrode post together constitute a negative electrode terminal. A maximum value of a gap between an outer circumferential surface of the negative electrode post and an inner circumferential surface of the negative electrode bushing in the negative electrode terminal is 0.5 mm or more and 2.5 mm or less. A rib is provided in a lower part of the negative electrode bushing, and a minimum value of a protrusion height of the rib is 1.5 mm or more and 4.0 mm or less. A distance between a surface of the electrolyte solution and a lowermost portion of the negative electrode bushing is 15 mm or less.