Battery Cell Pressure Chamber Control for Dendrite Prevention
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Solution Overview
Problem
Rechargeable energy storage devices, such as lithium metal battery cells, face performance degradation due to internal pressure increases during cycling, which can lead to dendrite formation and separator breakage, limiting their volume and efficiency.
Innovation Solution
A pressure control apparatus with a housing, a movable cell plate, a pressure chamber filled with pressurized fluid, and a valve that releases excess fluid when pressure exceeds a threshold, managed by pressure sensors and a fluid pump, to maintain optimal external pressure on the battery cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If initial external pressure is applied to the battery structure to prevent lithium dendrite growth, then dendrite prevention is improved, but internal cell pressure continuously increases during cycling leading to separator breakage
Solution Approach 1:
The patent applies a dynamic pressure control system where a piston moves within a pressure chamber to adjust the external pressure applied to the battery cell. As the battery expands during cycling, the piston moves to maintain optimal pressure, preventing both dendrite formation and separator breakage. This dynamic adjustment resolves the contradiction between maintaining sufficient pressure for dendrite prevention and avoiding excessive pressure that causes separator breakage.
Solution Approach 2:
The system incorporates pressure sensors that continuously monitor the external pressure applied to the battery cell and provide feedback to the control system. This feedback mechanism enables real-time adjustment of the piston position and pressure chamber volume to maintain pressure within the optimal range, preventing both dendrite growth and separator failure.
2Quantity of substance
If the battery cell volume is increased to improve energy storage capacity, then energy density is improved, but internal cell pressure increases leading to performance degradation
Solution Approach 1:
The pressure control system is segmented into distinct functional components: a pressure chamber separated from the battery cell chamber by a movable piston, with independent pressure sensors and fluid control mechanisms. This segmentation allows the pressure control system to operate independently from the battery cell, enabling volume expansion for higher capacity without compromising pressure management.
Solution Approach 2:
The patent introduces a fluid medium (hydraulic fluid) as an intermediary between the pressure control mechanism and the battery cell. This fluid transmits pressure forces through the piston to the battery cell, allowing smooth and controlled pressure adjustment that accommodates battery volume changes during cycling and charging, thereby preventing performance degradation.
3Reliability
If a fixed volume housing is used to apply initial external pressure, then dendrite prevention is improved, but the housing cannot accommodate battery expansion during cycling
Solution Approach 1:
The housing incorporates a dynamic piston assembly that can move within the pressure chamber to accommodate battery expansion. The piston is connected to the battery cell and moves with it during cycling, while maintaining constant pressure through the hydraulic fluid system. This dynamic design allows the fixed-volume housing to adapt to changing battery dimensions without compromising dendrite prevention.
Solution Approach 2:
The system uses a flexible sealing arrangement between the piston and pressure chamber walls, allowing the piston to move smoothly while maintaining pressure integrity. This flexible sealing mechanism enables the rigid housing to accommodate battery expansion through piston movement, resolving the contradiction between fixed volume for pressure maintenance and adaptability for expansion.
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 solution effectively prevents dendrite formation and separator breakage by regulating internal pressure, thereby enhancing the longevity and performance of lithium metal battery cells.
Implementation Method 1
a pressure chamber having a volume of pressurized fluid therein
Implementation Method 2
a valve configured to allow a portion of the pressurized fluid to be removed from the pressure chamber when the pressure in the pressure chamber exceeds a threshold
Implementation Method 3
a fluid pump is operably connected to the pressure chamber to pressurize the pressure chamber with fluid
Data Source
AI summary
A pressure control apparatus for a battery cell includes a housing in which the battery cell is positioned, and a cell plate movably positioned in the housing and separating an interior of the housing into a cell chamber having the battery cell therein, and a pressure chamber having a volume of pressurized fluid therein. The apparatus further includes a valve configured to allow a portion of the pressurized fluid to be removed from the pressure chamber when the pressure in the pressure chamber exceeds a threshold.