Secondary Battery Terminal Heat-Resistant Insulating Layer
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Solution Overview
Problem
Secondary batteries connected in parallel face reliability issues due to short circuits, where the current interrupting mechanism or fuse part may not effectively prevent abnormal events, as the insulating member made of resin can melt, causing a closed circuit and potentially leading to large currents flowing through other batteries, resulting in abnormal events.
Innovation Solution
Incorporating an electrically insulating, intermediate heat-resistant layer or member with a resistivity of 1.0×10^4 Ω·cm or higher and a melting point of 400° C or higher between the terminal and the sealing plate, which prevents electrical connection even if the insulating member made of resin melts, thus avoiding a conduction path and preventing abnormal events in other secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If secondary batteries are connected in parallel, then productivity is improved by increasing power output, but reliability deteriorates because a short circuit in one battery can cause large currents to flow through other batteries when the insulating member melts
Solution Approach 1:
The electrically insulating, intermediate heat-resistant layer serves as a protective intermediary between the terminal and sealing plate, preventing direct electrical contact even when the resin insulating member melts. This ensures that parallel-connected batteries remain electrically isolated during short circuit conditions, allowing safe parallel operation for increased power output.
Solution Approach 2:
The heat-resistant layer is positioned beforehand between the terminal and sealing plate to cushion against the potential failure of the resin insulating member. This preventive measure ensures that even if the resin melts under high temperature, the electrical insulation is maintained, preventing abnormal events in parallel-connected batteries.
2Ease of manufacture
If an insulating member made of resin is used between the terminal and sealing plate, then ease of manufacture is improved, but the insulating member may melt under high temperature, causing electrical connection between terminal and sealing plate
Solution Approach 1:
The invention creates a composite insulating structure combining a resin insulating member with an electrically insulating, intermediate heat-resistant layer. The resin insulating member provides ease of manufacture and basic insulation, while the heat-resistant layer (which may be made of different material with higher thermal stability) provides high-temperature resistance, together forming a composite structure that maintains both manufacturability and 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
This configuration enhances the reliability of secondary batteries and battery packs by preventing large currents from flowing into other batteries in case of a short circuit, thereby reducing the likelihood of abnormal events and maintaining the integrity of the battery pack.
Implementation Method 1
an electrically insulating, intermediate heat-resistant layer or an electrically insulating, intermediate heat-resistant member is disposed between the terminal and the sealing plate
Implementation Method 2
an electrically insulating, intermediate heat-resistant layer or an electrically insulating, intermediate heat-resistant member is disposed between the terminal and the sealing plate
Data Source
AI summary
A secondary battery includes an electrode body that includes a positive electrode plate and a negative electrode plate; an outer body that houses the electrode body; a sealing plate that is made of metal and seals an opening of the outer body; and a positive electrode terminal that is electrically connected to the positive electrode plate. At least part of the positive electrode terminal is disposed on the battery outer side with respect to the sealing plate. An external insulating member made of resin is disposed between the sealing plate and the positive electrode terminal. The conduction path between the positive electrode plate and the positive electrode terminal is provided with a current interrupting mechanism. An electrically insulating, heat-resistant layer is disposed between the positive electrode terminal and the sealing plate.