Dual-Cathode Secondary Battery Layout for Nickel Stability Tradeoffs
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Solution Overview
Problem
As the nickel content in cathode active materials for lithium secondary batteries increases, the chemical structure and stability of the active material particles deteriorate, leading to gas generation during high SOC charging and discharging, and decreased rapid charging performance.
Innovation Solution
A secondary battery design featuring a first cathode group with a high nickel content lithium-nickel-based metal oxide and a second cathode group with a lower nickel content lithium-nickel-based metal oxide, each with distinct active material layers and structures, to improve stability and charge/discharge properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel content lithium-nickel-based metal oxide is used as cathode active material, then capacity properties are increased, but chemical structure stability deteriorates and gas is generated during high SOC charging and discharging
Solution Approach 1:
The battery is divided into two separate cathode groups: a first cathode group using high nickel content lithium-nickel-based metal oxide for high capacity, and a second cathode group using lower nickel content lithium-nickel-based metal oxide for high stability. This segmentation allows each cathode group to specialize in different functions, resolving the contradiction between capacity and stability.
Solution Approach 2:
Different nickel content cathode materials are applied to different cathode groups based on their specific functional requirements. The first cathode group uses high nickel content (0.85-0.95) for capacity, while the second cathode group uses lower nickel content (0.80-0.88) for stability, optimizing local properties for specific purposes.
2Quantity of substance
If high nickel content lithium-nickel-based metal oxide is used as cathode active material, then capacity properties are increased, but rapid charging performance decreases
Solution Approach 1:
The battery is divided into two separate cathode groups: a first cathode group using high nickel content lithium-nickel-based metal oxide for high capacity, and a second cathode group using lower nickel content lithium-nickel-based metal oxide for rapid charging. This segmentation allows each cathode group to specialize in different functions, resolving the contradiction between capacity and rapid charging performance.
3Use of energy by moving object
If high nickel content lithium-nickel-based metal oxide is used as cathode active material, then energy density is improved, but stability at high temperature deteriorates
Solution Approach 1:
The battery is divided into two separate cathode groups: a first cathode group using high nickel content lithium-nickel-based metal oxide for high energy density, and a second cathode group using lower nickel content lithium-nickel-based metal oxide for high temperature stability. This segmentation allows each cathode group to specialize in different functions, resolving the contradiction between energy density and thermal stability.
Data Source
AI summary
A secondary battery includes a first cathode group in which first cathodes are stacked adjacent to each other, a second cathode group in which second cathodes are stacked adjacent to each other, and anodes facing the first cathode or the second cathode. Each of the first cathodes includes a first cathode current collector and a first cathode active material layer on the first cathode current collector. Each of the second cathodes includes a second cathode current collector and a second cathode active material layer on the second cathode current collector. The second cathode active material layer has a different active material composition or a different stacked structure from that of the first cathode active material layer.