Battery Pack Insulating Pads Prevent Electric Arcs
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Solution Overview
Problem
The existing vehicle battery packs are prone to thermal runaway and fires due to the formation of electric arcs between battery modules and adjacent metallic components, which can occur when gaps between these components act as capacitors and allow off-gassing and foreign materials to enter, reducing insulation and causing electrical arcs.
Innovation Solution
The implementation of insulating cut-off pads made of heat-resistant materials in strategic locations within the battery pack, such as between endplates and casings, clamps, and between battery modules and structural members, to prevent the formation of electric arcs by eliminating potential capacitive gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic components (endplates, clamps, casing, structural members) are used in the battery pack, then structural strength and rigidity are improved, but the risk of electric arc formation increases due to capacitive gaps between components
Solution Approach 1:
An insulating member (intermediary component) is introduced between the battery module and the lower casing to prevent direct contact and eliminate capacitive coupling. This mediator maintains the structural support function while blocking the harmful electrical interaction that could lead to arcs and thermal runaway.
Solution Approach 2:
The harmful capacitive coupling effect is extracted and eliminated by introducing the insulating member. The insulating component removes the direct electrical pathway between metallic components, separating the structural support function from the electrical hazard.
2Ease of manufacture
If small gaps are left between battery modules and adjacent components for assembly tolerance, then ease of assembly is improved, but the insulating distance is reduced increasing electric arc risk
Solution Approach 1:
The insulating member acts as an intermediary that fills the gap between battery modules and adjacent components. It accommodates assembly tolerances while simultaneously providing adequate insulating distance to prevent electric arc formation, thus resolving the contradiction between ease of assembly and safety.
3Productivity
If battery cells are closely packed to maximize energy density, then productivity and energy capacity are improved, but the risk of thermal runaway increases due to reduced spacing for heat dissipation and gas venting
Solution Approach 1:
The harmful effect of heat and off-gas accumulation is extracted and managed by providing dedicated venting pathways and heat dissipation channels in the lower casing. The insulating member also helps channel heat away from the battery module while maintaining close packing for high energy density.
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 prevents electric arcs and subsequent thermal runaway and fires, significantly enhancing the safety of the battery pack by ensuring insulating distances are maintained and reducing the risk of electrical discharges.
Implementation Method 1
the foregoing portion leaving only a little gap from the battery module may potentially serve as a capacitor
Implementation Method 2
electric charges accumulated in the gap between the battery module and its adjacent components may form an electric arc
Implementation Method 3
first cut-off pads, each of which is made of an insulating material, disposed between the endplates of the battery modules and the lower casing
Data Source
AI summary
A safety structure for a vehicle battery pack includes: a battery module each including a plurality of battery cells stacked between opposite endplates; a lower casing which covers a lower side of the battery modules that are two-dimensionally arrayed; an upper cover coupled to an upper side of the lower casing and covering an upper side of the battery modules; and first cut-off pads, each of which is made of a heat-resistant and insulating material, disposed in a portion where a gap between the endplate of the battery module and the lower casing becomes locally narrow.