Battery Terminal Fuse Structure for High-Current Heat Suppression
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Solution Overview
Problem
Conventional secondary batteries face challenges in minimizing heat generation and ensuring reliability when high currents flow, particularly in applications like vehicle power supplies, due to inadequate mechanisms for safely managing excessive current.
Innovation Solution
The secondary battery design includes an external conductive member with an approximately annular thin portion that melts when a current of 1000 A or more flows, creating a high-resistance conduction path and preventing cantilevered states during assembly, while maintaining mechanical reliability and reducing electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fuse mechanism is used to cut off conduction path during excessive current, then safety is improved, but heat generation inside the battery increases due to high electrical resistance at connection points
Solution Approach 1:
The invention extracts the fuse function from the internal battery structure and relocates it to an external conductive member that connects the terminal to the battery case. This external fuse element is positioned away from the internal battery components, allowing it to melt and cut off the conduction path during excessive current without generating heat inside the battery, thus resolving the contradiction between safety and heat generation.
Solution Approach 2:
The external conductive member acts as an intermediary between the terminal and the battery case, incorporating a fuse element that provides the safety function while being electrically connected through low-resistance paths. This intermediary structure allows the fuse to perform its protective function without the high resistance and heat generation that would occur with conventional internal fuse mechanisms.
2Reliability
If a thin portion is made very thin to ensure melting at 1000 A, then current protection is improved, but mechanical strength and reliability during assembly deteriorate
Solution Approach 1:
The external conductive member features a thin portion with a specific thickness (0.01 mm to 0.05 mm) located only at the fuse element region, while other portions of the conductive member maintain greater thickness for mechanical strength. This local variation in thickness allows the fuse portion to melt at 1000 A for current protection while the thicker sections provide the necessary mechanical strength during assembly and handling.
Solution Approach 2:
The invention carefully controls the thickness parameter of the thin portion within a specific range (0.01 mm to 0.05 mm) to achieve the desired melting current of 1000 A. By optimizing this parameter, the fuse element becomes sufficiently thin to melt at the target current while maintaining enough structural integrity for assembly, resolving the contradiction between current protection and mechanical strength.
3Ease of operation
If the external conductive member has a through-hole for terminal insertion, then assembly ease is improved, but cantilevered state and load on thin portion increase during assembly
Solution Approach 1:
The external conductive member features an asymmetric structure where the thin portion is strategically positioned and shaped to minimize cantilevered effects during assembly. The through-hole is designed with specific dimensions and the thin portion is configured to avoid creating excessive leverage loads, allowing easy terminal insertion while preventing the thin portion from experiencing excessive mechanical stress during the assembly process.
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 effectively suppresses heat generation and enhances reliability by ensuring a stable conduction path, allowing for controlled energy release and improved safety during high-current conditions.
Implementation Method 1
The thin portion is configured to melt when a current of 1000 A or more flows through the secondary battery
Implementation Method 2
the approximately annular thin portion provided around the joining portion between the terminal and the external conductive member melts and cuts off a conduction path
Data Source
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AI summary
A secondary battery disclosed herein includes: an electrode body; a battery case; a terminal extracted from a terminal extracting hole to outside of the battery case; and an external conductive member joined to the terminal. The external conductive member has a through-hole into which a part of the terminal is inserted, and a joining portion between the external conductive member and the terminal is formed at a peripheral edge of the through-hole. The external conductive member has an approximately annular thin portion provided around the joining portion, and the thin portion is configured to melt when a current of 1000 A or more flows through the secondary battery.