Battery Core Pack Uniform Pressure Containment for Dendrite Suppression
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Solution Overview
Problem
Current techniques for controlling dendrite growth in lithium metal batteries are inadequate, leading to short circuits and degradation after a limited number of discharge/charge cycles due to non-uniform lithium plating and stripping.
Innovation Solution
A battery core pack design that applies a substantially uniform surface pressure of at least 50 psi to the cell stack using a containment structure and compliant pads, which distributes pressure evenly during charging and discharging, suppressing dendrite growth and extending cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal ions are re-plated onto the anode during charging, then the battery can be recharged, but non-uniform plating causes dendrite growth that pierces the separator and causes short circuits
Solution Approach 1:
The patent applies mechanical pressure (a physical parameter) to the battery cell to change the plating behavior of lithium ions. By applying pressure during charging, the plating becomes more uniform, preventing dendrite formation while maintaining rechargeability. This parameter change directly addresses the contradiction between rechargeability and reliability.
2Duration of action of moving object
If individual cells contract and expand during ion stripping and re-plating, then the battery functions during charge/discharge cycles, but this causes problematic dendrite growth on re-plating
Solution Approach 1:
The patent applies mechanical pressure during the charge/discharge cycles to modify the expansion/contraction behavior of the cells. This pressure parameter change suppresses the problematic dendrite growth that occurs during re-plating while maintaining the necessary ion stripping and re-plating functionality.
3Reliability
If current techniques are used to control dendrite growth, then some suppression may occur, but the techniques are less than satisfactory and battery life cycles are not extended
Solution Approach 1:
The patent introduces mechanical pressure as a new parameter to control dendrite growth, achieving superior results compared to current techniques. This pressure parameter not only suppresses dendrite growth effectively but also extends battery life cycles, simultaneously improving both reliability and duration.
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 uniform pressure effectively suppresses dendrite growth, maintaining cycle life and preventing cell degradation, with improved performance at pressures above 50 psi, resulting in a significant increase in battery life cycles.
Implementation Method 1
the containment structure imparts a substantially uniform surface pressure at certain value to the cell stack
Implementation Method 2
a pre-loaded surface pressure of at least about 50 psi... the housing has sufficient stiffness to maintain the surface pressure
Implementation Method 3
When a battery of this type discharges, lithium metal ions are stripped from the anode and travel to the cathode through the separator
Implementation Method 4
During charging, the ion flow is reversed and the metal ions are re-plated back onto the anode
Data Source
AI summary
Battery core packs employing minimum cell-face pressure containment devices and methods are disclosed for minimizing dendrite growth and increasing cycle life of metal and metal-ion battery cells.