Secondary Battery Asymmetric Electrode Coating

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Solution Overview

Problem

Secondary batteries face safety issues due to overlapping protrusions of carbon coating and electrode active material layers, leading to delamination and lithium ion precipitation, which can cause defects and potential ignition.

Innovation Solution

The secondary battery design features a carbon coating layer and an electrode active material layer on the electrode plates, where the ends of these layers are positioned differently, with protrusions formed at the coating start and end portions to prevent overlap, and the distance between their ends is set between 1 mm to 10 mm to ensure non-overlapping configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the carbon coating layer and electrode active material layer are formed with their ends at the same position, then the coating process is simplified, but protrusions overlap causing delamination and lithium ion precipitation

Engineering Contradiction:

Improvecoating process simplicityVSAvoidbattery safety

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by intentionally positioning the ends of the carbon coating layer and electrode active material layer at different locations along the electrode plate. This asymmetric arrangement prevents the protrusions at the layer ends from overlapping, thereby avoiding delamination and lithium ion precipitation while maintaining manufacturing feasibility through adjusted coating parameters

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by creating a specific spatial relationship between the carbon coating layer and electrode active material layer at their boundary regions. By controlling the relative positioning of layer ends and adjusting protrusion dimensions locally, the patent prevents harmful overlaps at critical interfaces while maintaining overall coating integrity

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If the protrusions of carbon coating layer and electrode active material layer are allowed to overlap, then the coating coverage is maximized, but delamination and lithium ion precipitation occur

Engineering Contradiction:

Improvecoating coverageVSAvoiddelamination and lithium ion precipitation

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful overlap of protrusions into a beneficial non-overlapping configuration by carefully controlling the positioning of layer ends. This approach maintains adequate coating coverage while transforming the risk of protrusion overlap into a safety feature that prevents delamination and lithium ion precipitation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the ends of carbon coating layer and electrode active material layer are positioned differently, then overlapping protrusions are prevented, but manufacturing precision requirements increase

Engineering Contradiction:

Improvebattery safetyVSAvoidlayer positioning accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by optimizing the distance between the ends of the carbon coating layer and electrode active material layer, as well as adjusting the dimensions of protrusions. These parameter adjustments ensure non-overlapping configuration while maintaining manufacturing precision within achievable tolerances

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10916778B2Secondary battery

Publication Date: 2021.02.09 SAMSUNG SDI CO LTD

AI summary

Disclosed is a secondary battery which can improve safety by forming a carbon coating layer and an electrode active material layer on an electrode plate such that ends of the carbon coating layer and the electrode active material layer are in different positions. As an example, the disclosed secondary battery comprises: an electrode assembly including a first electrode plate, a second electrode plate, and a separator interposed therebetween; and a case for receiving the electrode assembly, wherein the first electrode plate comprises: a first electrode collector; a carbon coating layer formed on at least one surface of the first electrode collector; and a first electrode active material layer covering at least a portion of the carbon coating layer, wherein the carbon coating layer and the electrode active material layer are formed such that the end of the carbon coating layer and the end of the first electrode active material layer are in different positions, and a protrusion is formed on at least one of the end of the carbon coating layer and the end of the first electrode active material layer.