Electric Storage Device With Segmented Positive Electrode
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Solution Overview
Problem
Existing electric storage devices face challenges in achieving high energy and output densities while maintaining durability, particularly in hybrid capacitors where lithium cobalt oxide and activated carbon are used, as they suffer from internal resistance issues and potential differences between electrodes leading to overcharge or overdischarge, which deteriorate the device.
Innovation Solution
The electric storage device incorporates a positive electrode system with two different types of positive-electrode mixture layers connected via a through-hole in the current collector, allowing ion transfer between them, and a negative electrode with a larger surface area and polyacene-based organic semiconductor, ensuring balanced potential and enhanced energy and output densities without compromising durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If positive-electrode mixture layers of different types are connected directly without ion transfer path, then potential difference between electrodes causes overcharge or overdischarge, but durability deteriorates
Solution Approach 1:
A through-hole is formed in the current collector to serve as an intermediary ion transfer path between the first and second positive-electrode mixture layers. This mediator enables balanced ion transfer, preventing potential difference accumulation and overcharge/overdischarge, while maintaining durability by avoiding direct contact between different electrode materials.
2Power
If electrode mixture material is coated thin to reduce internal resistance, then output density improves, but energy density reduces
Solution Approach 1:
The positive electrode is segmented into two different positive-electrode mixture layers (e.g., lithium cobalt oxide and activated carbon) with distinct functions. One layer provides high energy density while the other provides high output density, allowing both requirements to be met simultaneously without compromising either parameter.
3Power
If battery and capacitor are connected in parallel to supply great electric current, then output density improves, but energy density of whole device reduces
Solution Approach 1:
The patent merges a battery-type positive-electrode mixture layer (lithium cobalt oxide) and a capacitor-type positive-electrode mixture layer (activated carbon) into a single integrated positive electrode system. This combination achieves both high energy density and high output density in one device without requiring separate battery and capacitor components, avoiding the need for control circuits and reducing overall device complexity.
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
This configuration enables high energy and output densities while preventing electrode deterioration, as the through-holes facilitate ion transfer between the layers, maintaining the device's durability and efficiency during charging and discharging operations.
Implementation Method 1
a through-hole is formed on the current collector arranged between the first positive-electrode mixture layer and the second positive-electrode mixture layer
Implementation Method 2
employs an activated carbon, which is used for the electric double layer capacitor, for a positive electrode so as to accumulate charges by utilizing the electric double layer in the positive electrode
Implementation Method 3
employs a carbon material, which is used for a lithium ion secondary battery, for a negative electrode, and lithium ions are doped into the carbon material of the negative electrode so as to accumulate charges
Data Source
AI summary
A positive electrode system of an electric storage device includes first and second positive electrodes. The first and second positive electrodes include current collectors, and first and second positive-electrode mixture layers, respectively. The negative electrode system of the electric storage device has a negative electrode including a current collector and a negative-electrode mixture layer. The first positive electrode and the second positive electrode are arranged across the negative electrode. The first positive-electrode mixture layer and the second positive-electrode mixture layer are connected to each other, and of different types. Through-holes are formed in the current collector of the negative electrode arranged between the first positive-electrode mixture layer and the second positive-electrode mixture layer.