Chamfered Insulating Substrate for Protective Circuit Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The thermal runaway of lithium ion secondary batteries can lead to accidents due to inefficient heat conduction in protective elements with ceramic substrates, causing partial contact and reduced melting time of meltable conductors during abnormal conditions like over-charging or over-discharging.
Innovation Solution
A protective element with a chamfered corner on a rectangularly shaped insulating substrate ensures efficient heat conduction to the meltable conductor by preventing partial contact with the circuit substrate, even when mounted at a tilted angle, using a heat-generating element and meltable conductor configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic substrate with high thermal conductivity is used in the protective element, then heat dissipation occurs when the substrate contacts the circuit substrate at a tilted angle, but this reduces the melting time efficiency of the meltable conductor
Solution Approach 1:
The insulating substrate is designed with a chamfered corner (asymmetric shape) instead of a symmetric rectangular shape. This asymmetric design ensures that when the substrate is mounted at a tilted angle, the chamfered corner prevents partial contact with the circuit substrate, thereby preventing unwanted heat dissipation paths while maintaining efficient heat conduction to the meltable conductor for prompt interruption
2Ease of operation
If the insulating substrate is mounted at a tilted angle, then partial contact with the circuit substrate occurs, but this causes heat dissipation that reduces protective element reliability
Solution Approach 1:
The chamfered corner is pre-formed on the insulating substrate to prevent partial contact with the circuit substrate when mounted at a tilted angle. This preliminary structural feature creates an anti-action against the potential harmful effect of tilted mounting, ensuring that even with mounting angle variations, the substrate maintains proper spacing and prevents heat dissipation paths that would compromise protective reliability
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 chamfered design enhances the blowout property of the meltable conductor by suppressing heat dissipation and ensuring prompt interruption of the current path during abnormalities, thereby preventing accidents.
Implementation Method 1
a meltable conductor 83 is connected as a part of a current path between first and second electrodes 81, 82, and this meltable conductor 83 in the current path is blown by self-heating due to an overcurrent or by a heat-generating element 84 provided in the protective element 80
Implementation Method 2
The meltable conductor 83 is melted by this heat and gathers on the heat-generating element extracting electrode 88 to interrupt the current path between the first and second electrodes 81, 82
Data Source
AI summary
A protective element includes: a rectangurarly shaped insulating substrate; a heat-generating element formed on the insulating substrate; first and second electrodes laminated on a surface of the insulating substrate; first and second connecting terminals provided on a back surface of the insulating substrate and being continuous with the first and second electrodes; a heat-generating element extracting electrode provided on a current path between the first and the second electrodes and electrically connected to the heat-generating element; and a meltable conductor laminated on a region extending from the heat-generating element extracting electrode to the first and second electrodes and to be melted by heat to interrupt the current path between the first electrode and the second electrodes; wherein at least one of the corner portions of the insulating substrate is chamfered.