Bilayer Negative Electrode With Through-Hole Current Collector
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium-ion accumulators experience significant irreversible capacity loss due to lithium reaction with the electrolyte and surface reactions during the first charging cycle, limiting their energy density and requiring additional lithium sources to compensate for these losses.
Innovation Solution
A negative electrode design featuring a bilayer structure with a current collector having through holes, allowing lithium ions to diffuse from one active material layer coated with a metal layer to another, thereby compensating for irreversible capacity losses and enhancing lithium utilization throughout the electrode volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additional lithium is introduced into the negative electrode to compensate for irreversible capacity losses, then the energy density is improved, but the device complexity increases due to additional manufacturing steps and materials
Solution Approach 1:
The patent applies preliminary action by pre-lithiating the negative electrode before final assembly. The negative electrode is prepared with additional lithium in advance, allowing it to compensate for irreversible capacity losses that occur during the first charging cycle. This preliminary preparation ensures that sufficient lithium is available for subsequent charge-discharge cycles without requiring complex post-assembly modifications.
Solution Approach 2:
The patent implements the nesting principle by incorporating a lithium-containing layer within the multi-layer structure of the negative electrode. The negative electrode consists of multiple functional layers including an active material layer, a binder layer, and a lithium-containing layer nested between them. This nested structure allows the lithium source to be integrated seamlessly within the electrode architecture, avoiding additional external components.
2Stability of the object's composition
If the negative electrode uses a multi-layer structure with through-holes in the current collector, then the lithium diffusion is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the negative electrode into multiple functional layers separated by a current collector with through-holes. The electrode is segmented into an active material layer, a binder layer, and a lithium-containing layer, with the through-holes providing vertical channels for lithium ion transport. This segmentation allows each layer to perform its specific function while maintaining overall structural integrity and lithium distribution uniformity.
Solution Approach 2:
The patent implements local quality by creating regions with different properties within the negative electrode structure. The through-holes in the current collector create localized channels with high lithium conductivity, while the surrounding solid matrix provides structural support and hosts the active materials. This local differentiation optimizes lithium diffusion pathways without compromising the overall electrode structure.
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 design effectively minimizes irreversible capacity losses and improves the energy density of lithium-ion accumulators by ensuring homogeneous lithium diffusion and utilization, as demonstrated by improved cyclability and reduced irreversibility rates.
Implementation Method 1
allowing lithium ions to diffuse from one active material layer coated with a metal layer to another, thereby compensating for irreversible capacity losses and enhancing lithium utilization throughout the electrode volume
Implementation Method 2
part of the lithium will react with the electrolyte on the surface of the grains of active material of the negative electrode to form a passivation layer on its surface
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a negative electrode for a battery operating according to the principle of ionic insertion and deinsertion and/or according to the principle of alloy formation and de-alloying, said negative electrode comprising: -a first layer (3) comprising an active material deposited, via one of its faces, on a first face of a current collector (5); -a second layer (7) comprising an active material deposited, via one of its faces, on a second face of a current collector (5), said first face being opposite said second face;characterized in that the current collector (5) is provided with through holes (6) connecting the first layer to the second layer and in that the first layer is coated with a layer composed of a metal (1), the corresponding cations of which are those involved in the ionic insertion or deinsertion process and/or in the alloying and de-alloying process in the active material of the first and second layers.;