Tapered Electrode Active Material Layers for Battery Impregnation

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Solution Overview

Problem

Existing electrode assemblies for secondary batteries face issues with uneven impregnation of electrolyte solution and insufficient capacity due to the lack of specific structures to promote electrolyte solution supply to active material layers and prevent uneven distribution between positive and negative electrode plates.

Innovation Solution

The electrode assembly features positive and negative electrode plates with tapered active material layers inclined at specific angles, alternately laminated with separators to ensure even electrolyte solution distribution and retention, enhancing impregnation efficiency and capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrolyte solution is filled in the case to surround active material layers, then the active material layers are initially covered, but over time the electrolyte solution is reduced due to electrolysis or evaporation causing the active material layers to be exposed and creating uneven impregnation

Engineering Contradiction:
Improveelectrolyte solution retentionVSAvoiduniformity of electrolyte solution distribution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a built-up electrolyte solution structure with specific height variations in different regions. The electrolyte solution is retained at higher levels in certain areas (forming reservoirs) to ensure continuous supply to active material layers, while maintaining appropriate levels in other areas. This non-uniform distribution strategy addresses the contradiction by locally optimizing electrolyte retention where needed most.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-forming the built-up electrolyte solution structure before the electrolyte solution is reduced over time. The reservoirs and retention structures are prepared in advance, ensuring that when electrolyte solution levels drop, the stored electrolyte can immediately continue to impregnate the active material layers without interruption or uneven distribution.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If the electrolyte solution is reduced over time, then the active material layers become exposed, but this creates uneven impregnation and insufficient capacity for active materials

Engineering Contradiction:
Improveelectrolyte solution volumeVSAvoiduniformity of impregnation
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent creates local quality variations in electrolyte solution distribution by forming built-up structures with different heights in different regions. These localized reservoirs ensure that even when overall electrolyte volume is reduced, critical areas maintain sufficient electrolyte levels for uniform impregnation of active material layers.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of electrolyte solution distribution from uniform to non-uniform, creating a built-up structure with varying heights. This parameter change allows the system to maintain sufficient electrolyte volume in key areas while accommodating overall volume reduction, thereby preventing uneven impregnation and ensuring adequate active material capacity.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the active material layers expand and contract during charging and discharging, then the electrolyte solution flows out and back, but this creates insufficient capacity and uneven impregnation without proper structural support

Engineering Contradiction:
Improvebattery capacityVSAvoiduniformity of electrolyte solution distribution
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating built-up electrolyte solution structures with specific height variations that provide localized reservoirs. These structures ensure that during active material layer expansion and contraction, electrolyte solution is retained in appropriate quantities and distributed uniformly, preventing both insufficient capacity and uneven impregnation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements beforehand cushioning by pre-forming built-up electrolyte solution structures that act as reservoirs. These structures provide a buffer or cushion of electrolyte solution that compensates for volume changes during charging and discharging cycles, ensuring continuous and uniform impregnation of active material layers regardless of expansion and contraction movements.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 configuration promotes efficient supply and retention of electrolyte solution, preventing uneven impregnation and ensuring sufficient active material capacity, thereby improving battery performance.

Implementation Method 1

The electrolyte solution immersed in the active material layers stays around the active material layers due to surface tension so as to form the built up electrolyte solution

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS10658643B2Electrode assembly and method of manufacturing electrode assembly
Publication Date: 2020.05.19 TOYOTA INDUSTRIES CORP
  • US10658643B2 patent drawing
  • US10658643B2 patent drawing
  • US10658643B2 patent drawing

AI summary

A positive electrode plate includes a front positive electrode active material layer on a front surface of a positive electrode metal foil, and having a positive electrode large tapered portion that extends at an incline from one edge of the front surface of the positive electrode metal foil at a positive electrode large inclination angle. A negative electrode plate includes a front negative electrode active material layer on a front surface of a negative electrode metal foil, and having a negative electrode large tapered portion that extends at an incline from one edge of the front surface of the negative electrode metal foil at a negative electrode large inclination angle. The positive and negative electrode plates are alternately laminated with a separator interposed therebetween such that each of their front surfaces is oriented in the same direction in the rear-to-front directional axis along the thickness of the plates.