Gradient Insulator Electrode for Battery Safety and Energy Density
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Solution Overview
Problem
Nonaqueous electrolyte batteries, particularly those used in electric vehicles, face challenges in achieving high energy density and safety, with existing technologies struggling to balance energy capacity with safety concerns and internal resistance issues.
Innovation Solution
The development of an electrode with an active material-containing layer featuring a gradient of insulator particles, where the volume ratio of insulator particles decreases from the second face towards the first face, which suppresses side reactions and enhances uniform resistance, thereby improving the battery's life performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the discharge capacity per unit weight or unit volume is increased to achieve high energy density, then the energy density is improved, but the safety risk increases
Solution Approach 1:
The patent applies local quality by creating a density gradient within the electrode active material layer, where the concentration of electrolyte salt varies from the surface toward the collector. This gradient structure allows different regions of the electrode to have optimized properties: the surface region maintains high ion conductivity for safety, while the deeper regions maximize energy storage capacity, thus resolving the contradiction between energy density and safety.
2Use of energy by moving object
If a liquid organic electrolyte is used to achieve high discharge capacity, then the energy density is improved, but the ignitability and safety deteriorate
Solution Approach 1:
The patent changes the concentration parameter of electrolyte salt throughout the electrode active material layer by creating a density gradient. This parameter change optimizes the balance between ion conductivity (affecting discharge capacity) and safety (reducing ignitability risks). The gradient concentration distribution allows the electrolyte to function effectively while reducing the overall risk associated with liquid organic electrolytes.
3Reliability
If an all-solid-state secondary battery is used to improve safety, then the safety is improved, but the energy density and discharge capacity decrease
Solution Approach 1:
The patent employs a composite structure within the electrode active material layer, combining electrolyte salt with active material particles in a gradient distribution. This composite approach allows the benefits of solid-state safety to be maintained while the optimized gradient structure ensures sufficient ion conductivity and energy density, thus resolving the contradiction between safety and energy density.
4Use of energy by moving object
If a bipolar electrode structure is used to increase voltage and energy density, then the energy density is improved, but the uniformity of current distribution and resistance uniformity deteriorate
Solution Approach 1:
The patent applies local quality by implementing a density gradient in the electrode active material layer that varies the electrolyte salt concentration from the surface toward the collector. This gradient compensates for the non-uniform current distribution inherent in bipolar structures, ensuring that regions with higher current density have correspondingly higher ion conductivity, thus maintaining resistance uniformity across the electrode while preserving the high voltage benefits of the bipolar structure.
Data Source
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AI summary
According to one embodiment, an electrode (1) is provided. The electrode (1) includes a current collector (1a) and an active material-containing layer (1b). The active material-containing layer (1b) is provided on the current collector (1a). The active material-containing layer (1b) includes active material particles (11) and insulator particles (12). The active material-containing layer (1b) has a first surface (1b-1) facing the current collector (1a) and a second face (1b-2) as a surface of the active material-containing layer (1b). The second face (1b-2) includes a surface of a part of the insulator particles (12). A volume ratio of the insulator particles (12) decreases from the second face (1b-2) toward the first surface (1b-1) in the active material-containing layer (1b).