Lithium Metal Battery Pressurization for Stable Electrode Interfaces
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Solution Overview
Problem
Lithium metal batteries face issues with stability and shortened cycle life due to localized lithium deposition, electrode separation, and increased resistance during charging and discharging, leading to potential short circuits and deterioration of internal components.
Innovation Solution
Applying a predetermined pressure of 2 kgf/cm² to 30 kgf/cm², specifically 7 kgf/cm² to 12 kgf/cm² or 4 kgf/cm² to 25 kgf/cm², to lithium metal batteries using constant-position, constant-pressure, or constant-variable pressure pressurization methods to stabilize the battery during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as the negative electrode active material to achieve high energy density, then the energy density is improved, but localized electrodeposition occurs causing needle-like lithium formation that increases resistance and causes internal short circuits
Solution Approach 1:
The patent applies pressure as a physical parameter to control lithium deposition behavior. By maintaining a predetermined pressure of 0.1 MPa or more during charging, the lithium ions are forced to deposit uniformly across the negative electrode surface rather than forming localized needle-like structures. This pressure parameter change directly addresses the harmful electrodeposition pattern while preserving the high energy density benefit of lithium metal.
2Use of energy by moving object
If lithium metal is used as the negative electrode active material, then high energy density is achieved, but the separator and negative electrode interface grows apart during discharge increasing resistance
Solution Approach 1:
The patent applies pressure in advance and maintains it throughout charging and discharging cycles to prevent interface separation before it occurs. The predetermined pressure of 0.1 MPa or more keeps the separator and negative electrode in close contact during discharge, preventing the interface from growing apart and avoiding the associated resistance increase.
3Reliability
If pressure is applied to prevent localized electrodeposition and maintain interface contact, then battery stability is improved, but the device complexity increases due to pressurization system requirements
Solution Approach 1:
The patent specifies a minimum pressure threshold of 0.1 MPa rather than requiring a complex active control system. This parameter-based approach allows for simpler implementation using passive pressure maintenance mechanisms, such as pre-compressed structural elements or elastic components, thereby reducing device complexity while still achieving the reliability benefits of prevented electrodeposition and maintained interface contact.
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
Improves the stability and extends the lifetime of lithium metal batteries by preventing localized electrodeposition and maintaining minimal resistance, thereby enhancing safety and performance.
Implementation Method 1
the lithium metal battery is charged and discharged under a state where a pressure of 2 kgf/cm 2 or more is applied
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(c)
AI summary
A lithium metal battery according to one embodiment of the present disclosure comprises an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; an electrolyte that impregnates the electrode assembly; and a battery case that incorporates the electrode assembly and the electrolyte, wherein the negative electrode comprises a negative electrode current collector and a lithium metal layer formed on at least one surface of the negative electrode current collector, and wherein the lithium metal battery is charged and discharged under a state where a pressure of 2 kgf/cm2 or more and 30 kgf/cm2 or less is applied thereto.