Wound Cell Electrode Layout to Suppress Lithium Dendrites

Solution Overview

Problem

Existing battery technologies face issues with lithium dendrite formation and inefficient use of active materials, leading to reduced energy density and safety concerns due to the continuous coating process and risk of short circuits.

Innovation Solution

A wound cell design featuring an empty foil segment on the first electrode plate and a coated second head segment on the second electrode plate, where the active substance is applied only on one side of the empty foil segment facing the second head segment, forming a plug-in structure to prevent lithium precipitation and optimize material utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a continuous coating process is adopted for the electrode plate, then manufacturing efficiency is improved, but surface active substance is wasted and lithium precipitation risk increases

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidsurface active substance waste

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The electrode plate is divided into a coated section and an empty foil segment. The coated section contains active substance on both surfaces for normal electrochemical reactions, while the empty foil segment has active substance on only one surface. This segmentation allows the battery to utilize active material more efficiently without requiring continuous coating throughout the entire electrode plate length.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the electrode plate are given different coating characteristics. The coated section has active substance on both surfaces for high reactivity, while the empty foil segment has active substance on only one surface to prevent lithium precipitation. This local differentiation optimizes both energy density and safety by matching material distribution to functional requirements.

Inventive Principle:

Principle #3Local quality

2Productivity

If a continuous coating process is adopted for the electrode plate, then manufacturing efficiency is improved, but lithium precipitation risk increases due to short circuit at the first corner

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidlithium precipitation risk

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The electrode plate is divided into a coated section and an empty foil segment. The coated section contains active substance on both surfaces for normal electrochemical reactions, while the empty foil segment has active substance on only one surface. This segmentation allows the battery to utilize active material more efficiently without requiring continuous coating throughout the entire electrode plate length.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the electrode plate are given different coating characteristics. The coated section has active substance on both surfaces for high reactivity, while the empty foil segment has active substance on only one surface to prevent lithium precipitation. This local differentiation optimizes both energy density and safety by matching material distribution to functional requirements.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If active substance is coated on both sides of the second head segment, then energy density is improved, but material utilization efficiency must be optimized

Engineering Contradiction:

Improveenergy densityVSAvoidmaterial utilization efficiency

Core Design Contradiction:

Quantity of substanceVSLoss of substance

Solution Approach 1:

The electrode plate is divided into a coated section and an empty foil segment. The coated section contains active substance on both surfaces for normal electrochemical reactions, while the empty foil segment has active substance on only one surface. This segmentation allows the battery to utilize active material more efficiently without requiring continuous coating throughout the entire electrode plate length.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the electrode plate are given different coating characteristics. The coated section has active substance on both surfaces for high reactivity, while the empty foil segment has active substance on only one surface to prevent lithium precipitation. This local differentiation optimizes both energy density and safety by matching material distribution to functional requirements.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3678252B1Wound cell

Publication Date: 2023.09.06 NINGDE AMPEREX TECHNOLOGY LTD

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AI summary

The present application provides a wound cell, comprising a first and second electrode plates having a first and second current collectors respectively, the first electrode plate has an empty foil segment having an area where the first electrode plate is bent for the first time, and the second electrode plate has a second head segment; the second current collector in the second head segment is coated with active substance on both sides, and projections of a starting end and an ending end of the empty foil segment in a thickness direction fall on the second head segment. The purpose of the present application is to provide a wound cell to effectively avoid lithium dendrite while improving the utilization of the battery material and the energy density of the battery, thereby improving the safety performance of the battery.