Solid-State Pouch Cell Pack Pressure Control Using Drive Plates
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Solution Overview
Problem
Solid-state battery cells face issues with uneven expansion and contraction during charge and discharge cycles, leading to improper pressure distribution between layers, which can result in increased resistance, non-uniformities, capacity fade, and dendrite growth, among other problems.
Innovation Solution
A battery force management system that includes a drive unit to controllably apply force on solid-state pouch cells, using a combination of threaded drive rods and planetary gear assemblies or pulley systems to maintain optimal pressure by adjusting the position of end plates relative to the cells based on changes in cell stack pressure during charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible pouch is used to encase the layered structure, then the cell can accommodate expansion and contraction during charge and discharge, but uneven pressure distribution occurs between layers leading to increased resistance and capacity fade
Solution Approach 1:
A drive mechanism acts as an intermediary between the pouch and the cell layers, applying distributed force through multiple contact points via threaded drive rods and end plates to ensure uniform pressure distribution across the layers during charge and discharge cycles
Solution Approach 2:
The system dynamically adjusts the applied pressure parameter based on the cell's expansion and contraction state, maintaining optimal pressure distribution by changing the force magnitude in response to varying cell dimensions during charging and discharging
2Device complexity
If no active force management is applied, then the device complexity is reduced, but improper pressure management leads to dendrite growth and decreased cycle life
Solution Approach 1:
The drive mechanism is operably coupled to sense the cell's state and automatically adjust the applied force without external intervention, allowing the system to self-regulate pressure based on real-time cell expansion and contraction during charge and discharge cycles
Solution Approach 2:
The system incorporates feedback from the cell's dimensional changes during charging and discharging, using this information to dynamically adjust the applied pressure through the drive mechanism, ensuring optimal pressure is maintained throughout the battery's operational cycles
3Reliability
If threaded drive rods with planetary gear assemblies are used to adjust end plate position, then optimal pressure is maintained during charge and discharge, but the device complexity increases
Solution Approach 1:
The system replaces complex electronic control systems with a mechanically self-regulating drive mechanism that uses threaded drive rods and planetary gear assemblies to automatically adjust end plate position and maintain optimal pressure through mechanical feedback from the cell's expansion and contraction
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 system ensures even and optimal pressure distribution across battery cells, enhancing their operational performance by preventing issues like increased resistance and capacity fade, and maintaining consistent contact between layers, thereby extending the cycle life and stability of the battery pack.
Implementation Method 1
a first threaded drive rod operably coupled with the drive unit to rotate the first threaded drive rod with the first threaded drive rod operably coupled with a threaded portion of the first member
Implementation Method 2
The drive unit may comprise a planetary gear assembly with a planet gear operably coupled with the drive rod and a sun gear to drive the planet gear
Implementation Method 3
the anode and cathodes expand and contract during charge and discharge albeit unequally. Namely, the anode expands disproportionally more than the cathode shrinks, resulting in a net positive expansion of a cell as the ions move from the cathode to the anode when charging
Data Source
AI summary
Aspects of the disclosure involve a battery pack involving one or more stacks of battery cells, where the stacks of battery of cells are captured between plates or other members that are controlled to maintain force on the cells to manage the pressure on the cells in the stack. Some battery cells technologies, such as some forms of solid-state cells, optimally operate under a controlled stack pressure provided by the systems described herein.