Accumulator Terminal Nickel Plating Corrosion
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Solution Overview
Problem
Conventional accumulator devices face issues with increased electrical resistance and galvanic corrosion between electrode terminals, leading to potential short circuits due to the use of aluminum positive electrode terminals and nickel-plated terminals, especially when arrayed in series.
Innovation Solution
The accumulator device features an aluminum positive electrode terminal with a nickel-plating coating where the inner edge of the coating is within the bonding portion, and the negative electrode terminal is made of nickel, preventing oxidation and galvanic corrosion by ensuring the same material surface contact and avoiding nickel deposition on the negative electrode current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aluminum positive electrode terminal is used, then the terminal substrate provides good electrical conductivity, but the surface oxidizes during long-term service, leading to increased electrical resistance
Solution Approach 1:
The positive electrode terminal uses a composite structure with an aluminum terminal substrate and a nickel-plating coating layer. The aluminum substrate provides excellent electrical conductivity, while the nickel coating layer protects the aluminum surface from oxidation. This composite material approach resolves the contradiction by combining materials with complementary properties to maintain low electrical resistance throughout the service life.
2Object-affected harmful factors
If an aluminum positive electrode terminal with nickel-plating coating is used, then oxidation resistance is improved, but galvanic corrosion occurs at the welded portion during charging and discharging, leading to increased electrical resistance
Solution Approach 1:
The nickel-plating coating is applied selectively only to the outer end portion of the positive electrode terminal that protrudes outside the outer container. The inner edge of the nickel-plating coating is positioned within the bonding portion, so that the aluminum substrate remains exposed at the welded portion where it contacts the positive electrode sheet. This local quality approach allows the nickel coating to provide oxidation resistance at the external terminal surface while preventing galvanic corrosion at the internal welded portion by maintaining direct aluminum-to-aluminum contact.
3Ease of operation
If aluminum positive electrode terminals are welded to copper or nickel negative electrode terminals in series array, then electrical connection is achieved, but galvanic corrosion occurs at the welded portion during charging and discharging
Solution Approach 1:
The invention makes both the positive electrode terminal surface and negative electrode terminal surface nickel-plated (or nickel material). This homogenizes the terminal material composition, eliminating the aluminum-copper or aluminum-nickel dissimilar metal joints that cause galvanic corrosion in series connections. By ensuring both terminals have the same nickel-based material composition, galvanic corrosion is prevented while maintaining good electrical connection capability.
4Object-affected harmful factors
If nickel-plating coating is formed on the entire positive electrode terminal, then oxidation resistance is improved, but nickel dissolves in the electrolytic solution and deposits on the negative electrode current collector, causing short circuit
Solution Approach 1:
The nickel-plating coating is applied only to the outer end portion of the positive electrode terminal that protrudes outside the outer container, with the inner edge positioned within the bonding portion. This selective local plating provides oxidation resistance where needed (at the external terminal surface) while preventing nickel dissolution into the electrolytic solution and subsequent deposition on the negative electrode current collector, thereby avoiding short circuits.
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
This configuration prevents oxidation and galvanic corrosion, maintaining low electrical resistance and avoiding short circuits even after long-term service, ensuring reliable performance when accumulator devices are arrayed in series.
Implementation Method 1
the nickel-plating coating is formed on the surface of an outer end portion of the terminal substrate located outside the outer container... prevent an increase in electrical resistance between the electrode terminals
Implementation Method 2
two outer films bonded air-tightly to each other at a bonding portion formed along the respective outer peripheral edge portions
Data Source
AI summary
An accumulator device includes: an outer container with mutually overlapped outer films bonded air-tightly to each other at a bonding portion formed along respective outer peripheral edge portions; an electrode unit accommodated inside the outer container and including positive and negative electrode sheets stacked one on another with a separator disposed therebetween, the positive and negative electrode sheets each including a current collector on which an electrode layer is formed; positive and negative electrode terminals provided to protrude from inside the outer container to outside through the bonding portion; and an electrolytic solution injected in the outer container. The positive electrode terminal includes an aluminum terminal substrate and a nickel-plating coating formed on a surface of an outer end portion of the terminal substrate located outside the outer container; an inner edge of the nickel-plating coating is located within the bonding portion.