Lithium Accumulator with 3D Electrodes and Porous Separator
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Solution Overview
Problem
Lithium batteries face safety issues with graphite electrodes, such as overheating and lithium metal growth, which limit their capacity and size, and existing technologies struggle to achieve high energy density and voltage while maintaining safety.
Innovation Solution
A lithium accumulator design featuring three-dimensional electrodes with a minimum thickness of 0.5 mm, using a homogenous mixture of conductive components and active materials with hollow sphere morphology, and a highly porous ceramic separator, allowing for the use of lithium metal as a negative electrode, which increases safety and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite is used as an active material for the negative electrode, then the battery can operate, but safety problems occur such as overheating, swelling, and risk of explosion or fire when the battery weight exceeds 0.5-1 kg
Solution Approach 1:
The patent extracts graphite from the negative electrode composition and replaces it with lithium metal. This removal of the problematic graphite material eliminates the safety issues associated with graphite-based batteries at higher weights, while maintaining the battery's operational functionality through the use of lithium metal as the active material.
Solution Approach 2:
The patent changes the physical and chemical parameters of the negative electrode by using lithium metal with specific purity (99.9% or higher) and controlling its form (foil, powder, or granules). This parameter change enables the battery to achieve both high weight and high safety, as lithium metal does not exhibit the same safety problems as graphite when scaled up.
2Quantity of substance
If lithium metal is used as a negative electrode in planar thin-film configuration, then high energy density can be achieved, but lithium metal grows in the form of dendrites during charging and discharging, causing electric short circuit
Solution Approach 1:
The patent applies local quality by using a highly porous separator material with specific pore structure and composition that is locally positioned between the lithium metal negative electrode and the positive electrode. This localized structural feature prevents dendrite penetration while maintaining high energy density, as the separator's specific properties at the critical interface prevent short circuits without compromising the overall battery design.
Solution Approach 2:
The patent introduces a highly porous separator as an intermediary layer between the lithium metal negative electrode and the positive electrode. This mediator prevents direct contact and potential short circuits caused by dendrite growth, while still allowing ionic transport. The separator acts as a protective intermediate that enables the use of lithium metal without the dendrite-related safety problems.
3Quantity of substance
If the thickness of planar electrodes is increased to improve energy storage capacity, then volumetric capacity increases, but the electrodes overheat and exhibit poor vibration resistance
Solution Approach 1:
The patent transitions from two-dimensional planar electrodes to three-dimensional electrode structures. The negative electrode is formed as a porous mass or aggregate of lithium metal particles rather than a flat thin-film layer. This dimensional change allows for better heat dissipation throughout the three-dimensional structure, preventing overheating while maintaining high energy storage capacity through increased volumetric utilization.
Solution Approach 2:
The patent employs porous materials for the electrodes, particularly the negative electrode made of porous lithium metal aggregate with controlled porosity (30-70%). This porous structure provides increased surface area for electrochemical reactions, improved heat dissipation pathways, and better mechanical flexibility, thereby preventing overheating and improving vibration resistance while maintaining high energy storage capacity.
4Reliability
If graphite is replaced with lithium titanate spinel Li4Ti5O12 (LTS) to improve safety parameters, then safety is improved, but cell voltage significantly decreases
Solution Approach 1:
The patent inverts the conventional approach by using lithium metal (the more reactive and higher voltage material) as the negative electrode instead of using it as the positive electrode or using it in combination with LTS. This inversion allows the battery to achieve both high voltage (from the lithium metal/LTS combination) and high safety (through the use of porous electrodes and separators that prevent dendrite formation and improve thermal management).
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 design achieves up to five times higher voltage and energy storage capacity compared to lead accumulators, with improved safety and faster charging capabilities, while being cost-effective and vibration-resistant.
Implementation Method 1
The lithium batteries are filled with an electrolyte, which is a non-aqueous solution of a lithium salt in an organic polar solvent
Implementation Method 2
at least one electrode comprises a homogenous, compressed mixture of an electron conductive component and an active material, capable to absorb and extract lithium
Data Source
AI summary
A lithium accumulator includes at least two three-dimensional electrodes separated by a separator and encased together into an accumulator body with an electrolyte that is a non-aqueous solution of a lithium salt in an organic polar solvent. The two electrodes have a minimum thickness of 0.5 mm each. At least one electrode is a homogenous, compressed mixture of an electron conductive component and an active material. The active material is capable of absorbing and extracting lithium in the presence of electrolyte. The porosity of the pressed electrodes is 25 to 90%. The active material has morphology of hollow spheres with a wall thickness of maximum 10 micrometers, or morphology of aggregates or agglomerates of maximum 30 micrometers in size. The separator includes a highly porous electrically insulating ceramic material with open pores and porosity from 30 to 95%.