Insulating Layer for Battery Electrode Heat Management
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Solution Overview
Problem
Nonaqueous power storage elements, such as lithium ion secondary batteries, face challenges in achieving higher output, higher capacity, and longer life due to safety issues like heat generation when the cathode and anode are short-circuited, leading to melting of the separator and abnormal heat generation.
Innovation Solution
An electrode with an insulating layer containing 80% insulating inorganic particulate and a resin, applied using a specific liquid with a controlled viscosity and boiling point, is used to form a porous structure that reduces heat generation by improving bonding strength and reducing resin content, thereby suppressing heat when the cathode and anode are short-circuited.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is disposed between the cathode and anode to prevent short-circuit, then safety is improved, but when short-circuit occurs the separator melts and heat generation expands abnormally
Solution Approach 1:
The insulating layer is segmented into multiple functional zones: a first insulating layer with resin and inorganic particulates for heat resistance, and a second insulating layer with different inorganic particulates for bonding strength. This segmentation allows each layer to address specific aspects of the heat generation problem independently.
Solution Approach 2:
The insulating layer uses composite materials combining organic resin with multiple types of inorganic particulates (alumina, silica, titania, zirconia) in specific proportions. This composite structure provides both heat resistance and bonding strength, preventing separator melting while controlling heat generation during short-circuit events.
2Strength
If an insulating layer with high resin content is used to improve bonding strength, then bonding strength is improved, but heat generation is increased
Solution Approach 1:
The resin content is precisely controlled within 1-20 mass% of the insulating layer, and the inorganic particulate content is controlled at 80-99 mass%. This parameter optimization ensures sufficient bonding strength while minimizing heat generation, as the inorganic particulates provide structural integrity without the thermal issues of high resin content.
Solution Approach 2:
The composite of resin and inorganic particulates creates a balanced structure where the resin provides bonding adhesion and the inorganic particulates (alumina, silica, titania, zirconia) provide heat resistance and structural strength, achieving both bonding strength and heat generation control simultaneously.
3Object-generated harmful factors
If an insulating layer with high inorganic particulate content is used to reduce heat generation, then heat generation is reduced, but bonding strength decreases
Solution Approach 1:
The composite material combines 1-20 mass% resin with 80-99 mass% inorganic particulates, creating a synergistic effect where the small amount of resin provides sufficient bonding adhesion while the dominant inorganic particulates ensure heat resistance and structural integrity, preventing both heat generation and bonding strength issues.
Solution Approach 2:
Different inorganic particulates are distributed throughout the insulating layer with specific content ratios: alumina (30-70 mass%), silica (10-50 mass%), titania (5-20 mass%), and zirconia (5-20 mass%). This local quality distribution optimizes both bonding strength and heat generation reduction in different regions of the insulating layer.
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 solution effectively reduces heat generation during short-circuit events, enhancing the safety and performance of nonaqueous power storage elements by maintaining the structural integrity of the insulating layer and preventing excessive heat buildup.
Implementation Method 1
the insulating layer contains an insulating inorganic particulate... effectively reduces heat generation during short-circuit events... maintaining the structural integrity of the insulating layer and preventing excessive heat buildup
Implementation Method 2
an organic solvent having a boiling point of from 140 to 300 degrees C.... applying the above-described insulating layer application liquid onto the electrode mixture layer to form an insulating layer
Data Source
AI summary
An electrode is provided which includes an electrode substrate, an electrode mixture layer overlying the electrode substrate, and an insulating layer overlying the electrode mixture layer. The electrode mixture layer contains an active material and a void. The insulating layer contains a resin and an insulating inorganic particulate accounting for 80% by mass of the insulating layer. In a boundary region of the electrode mixture layer with the insulating layer, the resin and the insulating inorganic particulate are present in a part of the void.