Li-Ion Cell Architecture for Extreme Fast Charging Stability
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Solution Overview
Problem
Existing Li-ion batteries struggle with achieving extreme fast charging capabilities due to heat generation, inefficient ion transport, and the risk of side reactions, making it difficult to charge quickly without compromising energy density and safety.
Innovation Solution
The rechargeable battery cells incorporate a conductive current collector coated with a composite containing at least 30% Si by weight, a high porosity separator with at least 38% porosity, and an electrolyte capable of carrying Li-ions, along with a pressurized interface between the anode and cathode to manage volumetric changes, enabling sequential charging and discharging to achieve 70% usable capacity within 15 minutes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher charging currents are supplied to achieve extreme fast charging, then charging speed is improved, but heat generation increases and side reactions risk increases
Solution Approach 1:
The patent employs a porous separator with high porosity (at least 38%) to facilitate faster ion transport between electrodes during extreme fast charging. The porous structure provides multiple pathways for Li-ion movement, reducing ionic resistance and enabling higher charging currents without excessive heat buildup, thus resolving the contradiction between charging speed and heat generation.
Solution Approach 2:
The patent uses composite electrode materials, specifically a conductive current collector coated with a composite containing at least 30% Si by weight. This composite anode material combines silicon's high capacity with conductive additives to maintain electrical conductivity during rapid charging, enabling faster charging while managing heat generation through the composite's thermal and electrical properties.
2Speed
If higher charging currents are supplied to achieve extreme fast charging, then charging speed is improved, but the risk of side reactions increases
Solution Approach 1:
The high porosity separator (at least 38%) not only facilitates ion transport but also provides a safety mechanism by allowing rapid ion movement that prevents concentration gradients and localized stress that could trigger side reactions. The porous structure ensures uniform ion distribution across the electrode interface, reducing the risk of dendrite formation and other side reactions during extreme fast charging.
Solution Approach 2:
The patent changes the physical parameters of the battery components, specifically the separator porosity (increased to at least 38%) and anode composition (at least 30% Si by weight in composite). These parameter changes enable the system to handle higher charging currents by improving ion transport efficiency and electrode stability, thereby reducing side reactions while maintaining fast charging capability.
3Speed
If a high porosity separator is used to facilitate faster ion transport, then ion transport efficiency is improved, but energy density may be reduced
Solution Approach 1:
The patent uses a high porosity separator (at least 38%) to enable extreme fast charging by facilitating rapid ion transport. The porous structure provides multiple pathways for Li-ion movement, reducing ionic resistance and enabling faster charging rates. This directly addresses the ion transport efficiency requirement while the thin design minimizes the volume penalty.
Solution Approach 2:
The separator is designed as a thin film with high porosity, combining the benefits of thinness (minimal volume occupation preserving energy density) with high porosity (fast ion transport). The thin film structure allows the separator to occupy minimal space between electrodes while maintaining sufficient mechanical integrity and ionic conductivity for extreme fast charging application.
4Quantity of substance
If anode materials with high capacity are used to increase energy density, then energy density is improved, but volumetric changes during charging increase
Solution Approach 1:
The patent employs a composite anode material consisting of silicon (at least 30% by weight) combined with conductive additives. This composite structure provides high capacity from silicon while the conductive matrix maintains electrical conductivity and accommodates volumetric changes. The composite design allows the anode to expand and contract during charging cycles without structural failure, preserving both high energy density and mechanical integrity.
Solution Approach 2:
The patent changes the anode material composition to include at least 30% Si by weight in a composite structure. This parameter change enables the anode to achieve high capacity while the composite formulation and structural design accommodate the associated volumetric changes during charging, preventing electrode degradation and maintaining cycle life.
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 configuration allows for extremely fast charging of at least 70% of usable capacity within 15 minutes while maintaining energy density and cycle life, minimizing heat generation and side reactions, thus overcoming the limitations of traditional charging methods.
Implementation Method 1
An electrolyte in contact with the anode, the cathode, and the separator, may be capable of carrying Li-ions between the anode and the cathode
Implementation Method 2
a high porosity separator between the anode and the cathode, such as a separator having a porosity of at least 38%
Implementation Method 3
The at least one anode may contain mixtures and/or composites of Si—C within a porous structure
Data Source
AI summary
Rechargeable battery cells and methods for extreme fast charging are disclosed. For example, such a rechargeable battery cell might be chargeable to at least 70% of usable capacity within 15 minutes. Such a rechargeable battery cell may include an anode having at least one surface with a reversible areal capacity, after formation, up to 8.0 mAh/cm2, containing a Si—C composite within a porous structure and including a carbon-based conductive additive, wherein the Si—C composite is at least 30% Si by weight, and the material is at least 85% Si—C composite. The rechargeable battery cell may also include a cathode having at least one surface with a reversible areal capacity, after formation, up to 6 mAh/cm2, wherein a ratio of areal capacity of the at least one surface of the anode to the at least one surface of the cathode is between 1.15 to 1.45.