Rigid Lithium-Ion Cell Pressure Control for Anode Volume Change
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Solution Overview
Problem
Lithium-ion batteries using silicon or lithium metal anodes face mechanical stress, particle cracking, electrolyte interface instability, and lithium dendrite growth due to significant volume changes during lithiation and de-lithiation cycles, which reduce battery lifespan and safety.
Innovation Solution
Applying controlled pressure from within the rigid housing using an adjustable pressure element, such as an inflatable bag or mechanical positioning unit, to maintain uniform pressure distribution and stabilize the SEI layer, reduce particle cracking, and prevent lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon or lithium metal anodes are used to achieve higher theoretical capacity, then battery capacity is improved, but mechanical stress and particle cracking occur due to significant volume expansion and contraction
Solution Approach 1:
The patent employs a flexible bladder that can dynamically adjust its volume to accommodate the expansion and contraction of the silicon or lithium metal anode during lithiation and de-lithiation cycles. This dynamic adjustment maintains continuous contact between the anode and cathode while relieving mechanical stress, preventing particle cracking, and preserving electrode structural integrity throughout battery cycling
Solution Approach 2:
The patent changes the physical state and volume of the electrolyte within the flexible bladder to match the volume changes of the anode material. By adjusting the electrolyte volume parameter in response to anode expansion and contraction, the system maintains optimal electrode contact and prevents mechanical degradation while preserving the high capacity benefits of silicon or lithium metal anodes
2Stability of the object's composition
If graphite anode is used to achieve stability and avoid volume changes, then mechanical stress and particle cracking are reduced, but battery theoretical capacity decreases
Solution Approach 1:
The flexible bladder dynamically adapts its volume to match graphite anode expansion and contraction, maintaining stable electrode contact throughout cycling. This dynamic adjustment preserves the inherent stability and mechanical integrity of graphite anodes while preventing capacity loss from poor contact, enabling the system to achieve both stability and optimal capacity utilization
3Quantity of substance
If volume expansion and contraction occur during lithiation and de-lithiation cycles, then higher capacity is achieved, but electrolyte interface instability and lithium dendrite growth occur
Solution Approach 1:
The flexible bladder acts as an intermediary between the anode and cathode, absorbing volume changes and maintaining uniform pressure on the electrodes. This intermediary function stabilizes the electrolyte interface by preventing direct mechanical stress transmission, eliminating conditions that lead to dendrite growth and interface instability while preserving high capacity cycling
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
Enhances battery performance by improving lithium diffusion, maintaining electrode-electrolyte contact, and reducing mechanical stress, thereby extending cycle life and safety.
Implementation Method 1
applying a controlled pressure from within the rigid housing using an adjustable pressure element
Implementation Method 2
maintain uniform pressure distribution and stabilize the SEI layer
Implementation Method 3
improving lithium diffusion
Data Source
AI summary
A device that includes an electrochemical cell that includes a rigid housing, electrodes that comprises an anode, a cathode, and an adjustable pressure element configured to assert a controlled pressure on at least one of the electrodes. The controlled pressure is set to a first value during a first point in time and is set to a second value during a second point in time. The electrodes and the adjustable pressure element are located within the rigid housing.