Si-Composite Battery Cell for Fast Charging at High Areal Capacity
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Solution Overview
Problem
Current lithium-ion batteries face challenges in achieving extreme fast charging without compromising energy density and cycle life, as existing methods often result in heat generation, reduced durability, and safety concerns due to faster ion and electron movement.
Innovation Solution
The development of rechargeable battery cells with a conductive current collector coated with a composite containing at least 30% Si by weight, a high porosity separator, and an electrolyte capable of carrying Li-ions, along with a metal oxide-based cathode and pressurized interface to manage volumetric changes, enabling sequential charging and discharging that loads at least 70% of usable capacity within 15 minutes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher charging currents are supplied to achieve extreme fast charging, then charging speed is improved, but heat generation increases and battery durability deteriorates
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 allows efficient Li-ion movement while maintaining thermal stability, enabling high charging currents without compromising battery durability through enhanced heat dissipation and ion conductivity.
Solution Approach 2:
The patent utilizes composite materials including Si-C anode (containing at least 30% Si by weight) and metal oxide-based cathode to achieve both high capacity and structural stability. These composite materials accommodate volumetric changes during charging/discharging while maintaining integrity, enabling extreme fast charging without sacrificing cycle life through improved mechanical robustness.
2Productivity
If higher charging currents are supplied to achieve extreme fast charging, then charging speed is improved, but heat generation increases
Solution Approach 1:
The high porosity separator (at least 38%) provides enhanced ion transport pathways that reduce resistance and associated heat generation during fast charging. The porous structure facilitates efficient electrolyte distribution and heat dissipation, enabling high charging currents while controlling temperature rise.
3Quantity of substance
If a conductive current collector coated with Si composite is used, then areal capacity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs Si-C composite coating on conductive current collectors to achieve high areal capacity (anode up to 8.0 mAh/cm²). The composite structure combines silicon's high capacity with carbon's conductivity and structural stability, enabling straightforward manufacturing processes while achieving superior electrochemical performance through material composition rather than complex structures.
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 allows for extreme fast charging of lithium-ion batteries while maintaining energy density and cycle life, ensuring safe and efficient charging processes without significant trade-offs in performance indicators.
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%
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, and 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. Methods of charging rechargeable battery cells disclosed herein under conditions sufficient to enable charging of at least 70% of usable capacity to the rechargeable battery cell within 15 minutes, are also disclosed.