Secondary Battery Layer Structure for Low Self-Discharge

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Solution Overview

Problem

Current secondary batteries require further performance enhancement to improve energy density retention and minimize self-discharge.

Innovation Solution

Incorporating a tantalum oxide layer as a solid electrolyte between the negative and positive electrode active material layers, with nickel oxide and silicon oxide layers, and using titanium dioxide as n-type oxide semiconductor materials to optimize electron and ion movement, thereby reducing leakage and maintaining high energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional solid electrolyte layers are used between electrodes, then basic battery operation is achieved, but self-discharge occurs and energy density retention deteriorates over time

Engineering Contradiction:
Improveself-discharge rateVSAvoidenergy density retention
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

A tantalum oxide layer is introduced as an intermediary between the negative electrode active material layer and the solid electrolyte layer. This intermediate layer prevents direct contact and harmful interactions between the electrodes and solid electrolyte, thereby suppressing self-discharge and improving energy density retention over time.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite structure combining multiple materials: negative electrode active material, tantalum oxide, solid electrolyte, positive electrode active material, and nickel oxide layers. This composite architecture leverages the complementary properties of each material to achieve both low self-discharge and high energy density retention.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple protective layers are added to prevent self-discharge, then energy retention improves, but device structure becomes more complex

Engineering Contradiction:
Improveenergy density retentionVSAvoidlayer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Protective layers are applied selectively at specific interfaces where they are most needed. The tantalum oxide layer is positioned only between the negative electrode and solid electrolyte, while the nickel oxide layer is positioned between the positive electrode and solid electrolyte. This localized approach provides maximum protection with minimal added complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The battery structure is segmented into distinct functional layers with clear interfaces. Each layer serves a specific purpose: energy storage (electrode active materials), protection (tantalum oxide and nickel oxide layers), and ion conduction (solid electrolyte). This segmentation allows for optimized performance of each component while maintaining overall system reliability.

Inventive Principle:
Principle #1Segmentation

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 configuration significantly improves the secondary battery's performance by maintaining a high remaining energy rate over extended periods, preventing rapid self-discharge, and achieving energy retention of 80% or more after several hours.

Implementation Method 1

Incorporating a tantalum oxide layer as a solid electrolyte between the negative and positive electrode active material layers

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

an amorphous layer including tantalum oxide or a nanoparticle layer including a plurality of tantalum oxide nanoparticles may be formed by sputter deposition

Methodology Applied
Scientific EffectSputter deposition: Sputtering

Data Source

PatentEP3882996B1Secondary battery and manufacturing method therefor
Publication Date: 2024.03.27 NIHON MICRONICS KK
  • EP3882996B1 patent drawingFigure 1
  • EP3882996B1 patent drawingFigure 2
  • EP3882996B1 patent drawingFigure 3

AI summary

A technique of improving the performance of a secondary battery is provided. A secondary battery (100) according to an embodiment includes a first electrode (21), a second electrode (22), a first layer (11) disposed on the first electrode (21) and including a first n-type oxide semiconductor, a second layer (12) disposed on the first layer (11) and including a second n-type oxide semiconductor material and a first insulating material, a third layer (13) disposed on the second layer (12) and including tantalum oxide, and a fourth layer (14) disposed on the third layer (13) and including a second insulating material.