Battery Electrode Plate Multi-Step Coating and Calendering

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Solution Overview

Problem

Conventional battery electrode plate manufacturing processes limit battery capacity and cycling performance due to constraints on the thickness of the electrode plate and uneven material distribution, leading to poor surface smoothness and adherence issues.

Innovation Solution

A method involving multiple coating and calendering steps to form multiple electrode material layers on a current collector substrate, increasing the density and uniformity of the electrode active material, thereby enhancing battery capacity and cycling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the amount of electrode material coated once is increased to increase battery capacity, then the battery capacity increases, but the electrode material becomes uneven during calendering and is easy to drop out

Engineering Contradiction:

Improveamount of electrode materialVSAvoiduniformity of electrode material

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent divides the single coating process into multiple coating steps (first coating step and second coating step). Each step applies a layer of electrode material slurry, followed by drying and calendering. This segmentation allows the total amount of electrode material to be distributed in controlled increments, preventing the unevenness and dropout issues that occur when too much material is applied in a single step.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If the thickness of the electrode plate is increased to increase battery capacity, then the battery capacity increases, but the space in the battery shell is limited

Engineering Contradiction:

Improvebattery capacityVSAvoidthickness of electrode plate

Core Design Contradiction:

Quantity of substanceVSLength of stationary object

Solution Approach 1:

The patent improves the density and compactness of the electrode material locally through the calendering process applied after each coating step. By applying controlled pressure during calendering, the electrode material layers become more densely packed, increasing the amount of active material per unit volume without significantly increasing the overall plate thickness, thus accommodating more capacity within limited battery shell space.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If the amount of electrode material coated once is increased, then the battery capacity increases, but the surface of the electrode plate becomes not smooth

Engineering Contradiction:

Improveamount of electrode materialVSAvoidsmoothness of surface

Core Design Contradiction:

Quantity of substanceVSShape

Solution Approach 1:

By dividing the coating process into multiple steps with intermediate drying and calendering, each layer has a chance to set properly before the next layer is applied. This prevents the surface defects and unevenness that occur when excessive material is applied in one step, resulting in a smoother final electrode plate surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary drying and calendering actions between coating steps. The drying step removes solvent to stabilize the coated layer, and the calendering step pre-compacts the layer before subsequent coating. These preliminary actions prepare the surface for the next coating step, ensuring smoothness and preventing defects.

Inventive Principle:

Principle #10Preliminary action

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 method allows for a higher density and uniform distribution of electrode active material, improving battery capacity and cycling performance by repeating the coating, drying, and calendering process, resulting in a smoother surface and increased peeling strength between the electrode material and the current collector.

Implementation Method 1

coating an electrode material slurry containing an electrode active material onto a current collector substrate to thereby form an electrode material layer

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 2

drying the current collector substrate on which the electrode material layer is formed

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

calendering the current collector substrate on which the electrode material layer is formed

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentEP2417653B1Battery electrode plate and preparation method thereof

Publication Date: 2015.05.06 BYD CO LTD

Figure 1~2C
Figure 2D~3

AI summary

A battery electrode plate, a method of preparing thereof, and a secondary battery with the same are provided. The method of preparing the battery electrode plate comprises coating electrode material onto a current collector substrate (1), drying, calendaring, and repeating coating, drying and calendaring at least once. The capacity of batteries employing the battery electrode plate of the present invention is high.