Silicon Anode Cycle Life via High Temp Deep Discharge
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Solution Overview
Problem
Conventional battery technologies, particularly those using silicon-dominant anodes, face challenges in achieving stable cycle life due to large volume changes during lithiation and delithiation, leading to electrical isolation and capacity loss, as well as issues with trapped lithium that existing formation protocols do not adequately address.
Innovation Solution
Implementing high temperature deep discharge cycling during battery formation and operation to reactivate trapped lithium and prevent its entrapment, thereby enhancing cycle life by optimizing the formation protocol to include elevated temperatures and specific voltage and capacity limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional formation protocols are used for Si/Li batteries, then manufacturing process is simple, but cycle life is limited due to trapped lithium and SEI growth
Solution Approach 1:
The patent applies preliminary action by performing deep discharge cycles at elevated temperatures during the formation process before the battery enters normal operation. This pre-treatment reactivates trapped lithium and establishes a stable SEI layer, preventing future capacity loss and improving cycle life.
Solution Approach 2:
The patent changes key parameters of the formation protocol by implementing deep discharge cycles (discharging to lower voltage thresholds) at elevated temperatures (40-60°C). These parameter modifications enable lithium reactivation and SEI stabilization without requiring fundamental changes to the battery structure or chemistry.
2Reliability
If deep discharge cycling at high temperature is implemented, then cycle life and coulombic efficiency improve, but energy loss during cycling increases
Solution Approach 1:
The patent applies periodic action by implementing deep discharge cycles periodically during formation (e.g., every few cycles) rather than continuously. This approach provides the benefits of lithium reactivation and SEI stabilization while minimizing cumulative energy losses, as the battery returns to normal operation between deep discharge events.
3Quantity of substance
If silicon-dominant anodes are used to increase energy density, then capacity increases, but volume expansion causes electrical isolation and capacity loss
Solution Approach 1:
The patent applies beforehand cushioning by using deep discharge cycling at elevated temperatures during formation to pre-stabilize the silicon anode structure. This process creates a more robust SEI layer and reactivates trapped lithium before normal operation begins, cushioning against the detrimental effects of silicon volume expansion that would otherwise cause electrical isolation and capacity loss.
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 use of high temperature deep discharge cycling improves the cycle life and coulombic efficiency of silicon-dominant anode batteries by effectively managing lithium distribution and reducing solid electrolyte interphase growth, leading to increased energy density and prolonged battery performance.
Implementation Method 1
high temperature deep discharge cycling
Implementation Method 2
charging and discharging the cell
Data Source
AI summary
Systems and methods are provided for improvement of cycle life in Si/Li batteries using high temperature deep discharge cycling. One or more deep discharge cycles may be applied to a cell that includes a cathode, a separator, and a silicon-dominant anode, with each of the one or more deep discharge cycles including at least charging and discharging the cell, and with each of the one or more deep discharge cycles being performed at a higher temperature that is above normal operating temperature range. The higher temperature may be 40° C. or higher, 45° C. or higher, or around 45° C.