Lithium Ion Battery Anode Composite Volume Change Control
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Solution Overview
Problem
Lithium ion batteries face performance and lifetime limitations due to high volume changes in anode active materials during charge/discharge cycles, leading to electrode deformation and peeling from the current collector, which restricts the use of high-capacity anode materials.
Innovation Solution
An anode composite with a component selected from Si, SiOx, Si-C composite, alloys of Si and Bi/Sn, or conversion materials, combined with a porosity modifier to achieve a volume change of 180% or less and a peeling strength of 2.5 N/m or more, stabilizing the anode composite and preventing peeling during the first charge/discharge cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high capacity anode active materials (such as Si, SiOx, conversion materials) are used to increase battery capacity, then the achievable capacity of the lithium ion battery is improved, but the volume change during charge/discharge cycles increases significantly, leading to electrode deformation and peeling from the current collector
Solution Approach 1:
The patent applies parameter changes by carefully controlling the volume change of the anode composite during charge/discharge cycles to be 180% or less. This parameter control is achieved through selecting specific high-capacity anode active materials (Si, SiOx, conversion materials) and optimizing their composition and structure, thereby maintaining anode composite integrity while maximizing battery capacity.
Solution Approach 2:
The patent employs composite materials by combining high-capacity anode active materials with other components to form an anode composite. This composite structure allows the integration of materials with high lithium insertion/extraction capacity while managing their volume expansion through the composite's overall design, preventing peeling and maintaining structural stability.
2Reliability
If the volume change of the anode composite is limited to prevent peeling, then the anode composite integrity is maintained, but the achievable capacity of the lithium ion battery is restricted
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range: volume change of the anode composite is controlled to be 180% or less during charge/discharge cycles. This parameter threshold allows sufficient use of high-capacity materials while preventing excessive expansion that would cause peeling, thus balancing reliability and capacity.
Solution Approach 2:
The patent applies local quality by allowing different regions or components of the anode to have different properties. High-capacity materials with higher volume changes can be used in specific locations or compositions, while the overall anode composite is designed to maintain volume change within acceptable limits, enabling localized optimization without compromising overall stability.
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 approach allows the use of high-capacity anode materials while maintaining the integrity of the anode composite, resulting in extended lithium ion battery lifetime and improved performance by controlling volume change and peeling strength.
Implementation Method 1
both the anode and the cathode must be able to reversibly take up and dispense lithium ions to allow charge/discharge cycles of the lithium ion battery, also termed insertion and extraction of lithium ions, respectively
Data Source
AI summary
An anode for a lithium ion battery has an anode composite comprising an anode active material supported on a current collector, wherein the anode active material comprises a component selected from the group consisting of Si, SiOx, Si-C-composite, alloys of Si, Bi and/or Sn, conversion materials and combinations thereof, wherein the anode shows a volume change of 180 % or less during a first charge/discharge cycle of the lithium ion battery and wherein the anode composite has a peeling strength after the first charge/discharge cycle of 2.5 N/m or more. Further, a lithium ion battery with such an anode is presented.