Intermediate Layer Insulating Particle Distribution for Battery Safety
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Solution Overview
Problem
Existing energy storage devices face challenges in inhibiting short-circuit currents due to increased electric resistance in intermediate layers, which also raises internal losses and reduces energy efficiency.
Innovation Solution
A plate with a current collector, an intermediate layer containing electrically conductive and insulating particles, and an aggregation inhibitor, where the intermediate layer has a higher mass content of insulating particles in regions without active material, increasing electric resistance and preventing short-circuit currents without increasing internal device resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric resistance of the intermediate layer is increased to inhibit short-circuit current, then the effect of preventing short-circuit current is improved, but the electric resistance between the current collector and the active material layer increases, leading to increased internal loss and reduced energy efficiency
Solution Approach 1:
The intermediate layer is designed with spatially varying properties: regions adjacent to the tab extension have higher electric resistance (with insulating particles) to prevent short-circuit current, while other regions maintain lower electric resistance to minimize internal loss. This local differentiation allows the intermediate layer to simultaneously provide short-circuit protection and maintain energy efficiency.
Solution Approach 2:
The intermediate layer is segmented into functionally distinct regions: a first region with higher insulating particle content for short-circuit prevention near the tab, and a second region with lower insulating particle content for maintaining conductivity elsewhere. This segmentation enables different parts of the same layer to serve different purposes, resolving the contradiction between safety and efficiency.
2Quantity of substance
If a porous resin film separator is used to increase electric capacity per unit volume, then the electric capacity density is improved, but the risk of separator contraction and direct contact between plates increases
Solution Approach 1:
The intermediate layer with high electric resistance is pre-positioned in regions where short-circuit risk is highest (near tab extensions) before any thermal contraction occurs. This preliminary protective measure ensures that even if the separator contracts under thermal stress, the tab cannot make direct contact with the counter plate, preventing short-circuit current while allowing the use of thin separators for high capacity density.
3Reliability
If the intermediate layer is extended to the tab region to prevent direct contact, then short-circuit prevention is improved, but the internal resistance increases due to the electric resistance of the intermediate layer
Solution Approach 1:
The intermediate layer's insulating particle content is locally optimized: higher concentration in tab-adjacent regions for short-circuit prevention, lower concentration in other regions for maintained conductivity. This spatial variation allows the extended intermediate layer to prevent short-circuits without uniformly increasing internal resistance across the entire layer.
Solution Approach 2:
The intermediate layer is formulated as a composite material containing both conductive particles (to maintain low resistance in most regions) and insulating particles (to provide high resistance where needed). This composite structure enables the intermediate layer to simultaneously provide electrical connectivity where required and electrical insulation where safety is prioritized, resolving the contradiction between extended coverage and internal loss.
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 inhibits short-circuit currents between plates while maintaining energy efficiency by optimizing the mass content and distribution of insulating particles in the intermediate layer.
Implementation Method 1
the aggregation inhibitor is an anionic surfactant, a cationic surfactant, a bipolar surfactant, a non-ionic surfactant, or a polymer surfactant
Data Source
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AI summary
A plate includes a current collector, an intermediate layer layered on the current collector, and an active material layer layered on the intermediate layer. The intermediate layer contains conductive particles and insulating particles. At least a portion of an end edge of the intermediate layer is not covered with the active material layer. The intermediate layer has a higher mass content of the insulating particles in a region not covered with the active material layer than that in a region covered with the active material layer.