Radial Unit-Cell Battery Structure for Uniform Electrolyte Concentration

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Solution Overview

Problem

Existing secondary batteries face issues with non-uniform electrolyte concentration due to varying lithium ion concentrations near the positive and negative electrodes, affecting performance.

Innovation Solution

A secondary battery design where unit cells are radially assembled with a decreasing thickness in one direction, incorporating a current collector with through-holes, and a structured mixture layer to maintain uniform electrolyte concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If unit cells are radially assembled with decreasing thickness toward the central axis, then electrolyte concentration uniformity is improved, but device complexity increases

Engineering Contradiction:
Improveelectrolyte concentration uniformityVSAvoidbattery structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The battery is divided into multiple unit cells (n≥5) arranged radially around a central axis. Each unit cell has a specific thickness profile that decreases toward the central axis, allowing independent optimization of electrolyte distribution in different radial zones while maintaining overall system functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the battery have different unit cell thicknesses tailored to local requirements. The outer regions have thicker unit cells while inner regions have thinner unit cells, creating a non-uniform thickness distribution that compensates for electrolyte concentration gradients and maintains uniformity throughout the battery.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the ratio of inner to outer diameter is optimized, then energy density is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveenergy densityVSAvoiddiameter ratio control
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The diameter ratio (inner to outer) is optimized within a specific range to maximize energy density. By controlling this geometric parameter, the battery achieves higher active material content per unit volume while the radial assembly structure provides tolerance to manufacturing variations through its modular design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The radial segmentation into multiple unit cells allows the overall diameter ratio to be controlled by adjusting the number and individual dimensions of unit cells, providing flexibility in optimizing energy density while distributing manufacturing precision requirements across multiple components rather than a single monolithic structure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3916865B1Secondary battery having structure in which unit cells which become thinner in one direction are radially assembled, and device comprising same
Publication Date: 2025.10.29 LG ENERGY SOLUTION LTD
  • EP3916865B1 patent drawingFigure 1
  • EP3916865B1 patent drawingFigure 2
  • EP3916865B1 patent drawingFigure 3

AI summary

The present invention provides a secondary battery having a novel structure in which unit cells which become thinner in one direction are radially assembled, and a device comprising same, and when a collector having a through-hole in the thickness direction is to be applied, the variation range of the concentration of the electrolyte in the battery is reduced, helping to improve the performance of the battery.