Fusible Bus Bar Design for Energy Storage Overcurrent Protection
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Solution Overview
Problem
Conventional energy storage modules experience increased temperatures at external terminals due to overcurrents, leading to reduced gas tightness and potential damage from melted bus bars.
Innovation Solution
An energy storage apparatus with a bus bar featuring a fusible portion and enlarged width portions, where the fusible portion is positioned to accumulate heat and fuse quickly, interrupting the current path and preventing excessive temperature rise at external terminals, while stress relaxing portions manage stress concentration and heat diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bus bar connects external terminals of energy storage devices, then electrical connection is achieved, but temperature increases at external terminals when overcurrent flows
Solution Approach 1:
The bus bar is segmented into different portions with different width dimensions. The first portion has a smaller width than the second portion, creating a fusible portion that can be sacrificed to protect other components. This segmentation allows the bus bar to have both a robust connection area and a vulnerable protective area.
Solution Approach 2:
Different portions of the bus bar are given different local qualities through varying width dimensions. The first portion (fusible portion) has a smaller width making it more susceptible to melting, while the second portion has a larger width for stable connection. This local quality differentiation enables the bus bar to perform both protection and connection functions.
2Ease of manufacture
If the bus bar has uniform width, then manufacturing is simple, but stress concentration occurs and heat cannot be effectively managed
Solution Approach 1:
The bus bar features local quality variations with different width portions. The first portion has a smaller width for stress management and heat dissipation, while the second portion has a larger width for stable connection. This localized differentiation improves stress distribution and thermal management while maintaining manufacturing feasibility through standard forming processes.
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
Effectively suppresses temperature increases at external terminals by rapidly fusing the bus bar when an overcurrent occurs, preventing damage and ensuring the energy storage device's integrity.
Implementation Method 1
when an overcurrent flows in the energy storage apparatus, temperatures of the positive electrode terminal structure 103 and the negative electrode terminal structure 104 are increased
Implementation Method 2
the fusible portion is disposed at a position where the fusible portion overlaps with the neighboring member... rapidly fusing the bus bar when an overcurrent occurs
Data Source
AI summary
An energy storage apparatus includes: energy storage devices each including an external terminal, the energy storage devices being arranged in a first direction; a bus bar including a plate-like conductive portion; and a neighboring member disposed between the energy storage devices. The conductive portion includes: a fusible portion where a width size, which is a size in a second direction orthogonal to the first direction, is defined by a pair of edges, the width size being smaller than a width size of other portions of the conductive portion; and a pair of enlarged width portions contiguously formed with both sides of the fusible portion in the first direction, a width size of the pair of enlarged width portions increasing in a direction away from the fusible portion. The fusible portion is disposed at a position where the fusible portion overlaps with the neighboring member, and a size of the neighboring member in the first direction is equal to or more than a size of the fusible portion in the first direction.