Multi-Layer Battery Cell Case for Overcurrent and Strength Balance
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Solution Overview
Problem
Existing battery technologies face challenges in improving both the performance and safety of battery cells, particularly in ensuring structural strength and overcurrent capability while maintaining energy density and cycle life.
Innovation Solution
A battery cell design featuring a multi-layer case structure with varying resistivity, where layers with low resistivity enhance overcurrent capability and layers with high resistivity improve structural strength, combined with a barrel connection for electrode terminals, simplifying the structure and facilitating integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer case structure is used, then the device complexity is reduced, but the overcurrent capability and structural strength cannot be simultaneously optimized
Solution Approach 1:
The case is divided into multiple layers with different materials and functions. The first case layer provides overcurrent protection with low resistivity, while the second case layer provides structural strength with high tensile strength, allowing each layer to specialize in one function rather than requiring a single layer to do everything
Solution Approach 2:
The patent uses composite material structure where the first case layer is made of material with resistivity of 1×10-8Ω·m≤K1≤6×10-8Ω·m for overcurrent capability, and the second case layer is made of material with tensile strength of 250 MPa≤Rm2≤2000 MPa for structural strength, combining different material properties in a multi-layer configuration
2Reliability
If the first case layer thickness is increased to improve overcurrent capability, then the structural strength is enhanced, but the thickness of other structural layers becomes excessively small
Solution Approach 1:
The case thickness is segmented into multiple layers with specific thickness ratios. The first case layer thickness T13 and case total thickness T10 satisfy 0.15≤T13/T10≤0.85, ensuring the low-resistivity layer is thick enough for overcurrent protection without compromising the overall structural integrity
Solution Approach 2:
The multi-layer composite structure allows the first case layer (low resistivity) and second case layer (high tensile strength) to have different thickness proportions optimized for their respective functions, with the thickness ratio controlled to balance electrical and mechanical performance
3Ease of manufacture
If the first case layer thickness is decreased to maintain other layer thicknesses, then the processing difficulty increases and thermal runaway risk increases
Solution Approach 1:
The patent specifies a minimum thickness ratio T13/T10≥0.15 to ensure the first case layer is thick enough to prevent thermal runaway and maintain safe processing conditions, while the maximum ratio T13/T10≤0.85 ensures other structural layers retain sufficient thickness for strength and manufacturability
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 design enhances the overcurrent capability and structural strength of the battery cell, prolonging its service life and reducing the risk of thermal runaway, while maintaining energy density and cycle life.
Implementation Method 1
The case is of a multi-layer structure. The multi-layer structure has different resistivity
Data Source
AI summary
Embodiments of the present application disclose a battery cell, a battery, and a power consuming device. The battery cell includes an electrode assembly, a first electrode terminal, and a case. The electrode assembly includes a first tab. The case includes a barrel and a cover connected to the barrel. The barrel is disposed around an outer periphery of the electrode assembly. The cover includes the first electrode terminal. The first tab is electrically connected to the first electrode terminal by using the barrel. The case is of a multi-layer structure. The multi-layer structure has different resistivity.