Nonaqueous Lithium Storage Element High Temperature Durability
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Solution Overview
Problem
Conventional methods for producing nonaqueous lithium-type storage elements face challenges such as energy loss due to voltage reduction at high temperatures and increased resistance from lithium compound decomposition in the positive electrode, leading to inferior charging and discharging cycle characteristics under high load and durability at high temperatures.
Innovation Solution
A method involving a nonaqueous lithium-type storage element with a positive electrode containing a lithium compound, where lithium ions are pre-doped into the negative electrode, and the positive electrode active material layer includes a high content of carbon materials like activated carbon, optimized for high I/O characteristics, and a lithium compound that decomposes to reduce voltage reduction and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lithium compound is added to the positive electrode to improve high-temperature durability, then storage durability at high temperature is improved, but energy loss due to voltage reduction increases
Solution Approach 1:
The patent applies local quality by adding a lithium compound specifically to the positive electrode rather than uniformly distributing it throughout the battery. This localized addition targets the positive electrode's vulnerability to high-temperature degradation, improving storage durability at high temperature while minimizing the overall impact on energy loss. The lithium compound concentration is optimized at 1-50 wt% of the positive electrode active material to achieve the desired balance between durability improvement and energy loss minimization.
2Reliability
If the positive electrode contains lithium compound to enhance high-temperature stability, then storage durability is improved, but charging and discharging cycle characteristics under high load deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the lithium compound concentration within 1-50 wt% of the positive electrode active material. This parameter optimization ensures that the lithium compound provides sufficient high-temperature stability without excessive accumulation that would hinder ion transport. The controlled concentration range allows the positive electrode to maintain both high-temperature durability and acceptable charging/discharging performance under high load conditions.
3Loss of energy
If lithium compound is decomposed to reduce voltage reduction, then energy loss is reduced, but resistance increases leading to inferior cycle characteristics
Solution Approach 1:
The patent applies preliminary action by pre-doping lithium ions into the negative electrode before the battery enters service. This preliminary lithium ion insertion into the negative electrode creates a reservoir that can supply lithium ions during subsequent charging and discharging cycles. As the lithium compound in the positive electrode decomposes and releases lithium ions, the pre-doped negative electrode maintains electrical neutrality and facilitates smooth ion transport, thereby reducing voltage reduction and energy loss while preserving charging/discharging cycle characteristics under high load.
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 method results in a storage element with reduced energy loss at high temperatures, superior charging and discharging cycle characteristics under high load, and improved storage durability, achieving high I/O characteristics and energy density.
Implementation Method 1
non-Faraday reaction based on adsorption/desorption of anions, similar to an electric double layer capacitor, at about 3 V or higher, at the positive electrode
Implementation Method 2
Faraday reaction based on occlusion/releasing of lithium ions, similar to a lithium ion battery, at the negative electrode
Implementation Method 3
a lithium compound that decomposes to reduce voltage reduction and enhance durability
Data Source
AI summary
The invention relates to a method of producing a nonaqueous lithium-type storage element.