Positive Electrode Packing Density for High-Voltage Battery Cycling

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Solution Overview

Problem

Existing electrochemical devices, such as lithium-ion batteries, face challenges in achieving both excellent high-temperature cycle performance and low-temperature discharge performance under high-voltage conditions, due to issues like surface oxidizability of positive active materials and increased direct current resistance.

Innovation Solution

The electrochemical device incorporates a positive electrode with a high packing efficiency and density positive active material layer, optimized by controlling the volume ratio of the active material layer to the true active material volume, and an electrolytic solution containing nitrile and carboxylate compounds to reduce reactions between the positive electrode and the electrolyte.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the surface of positive active material is coated with metal oxide to improve high-temperature cycle performance, then high-temperature cycle performance is improved, but direct current resistance increases and low-temperature discharge performance deteriorates

Engineering Contradiction:

Improvehigh-temperature cycle performanceVSAvoiddirect current resistance

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolytic solution by introducing specific compounds (cyclic carboxylate 12-40 wt%, chain nitrile 0.5-10 wt%, cyclic carbonate 10-30 wt%, chain carbonate 30-60 wt%) to optimize the interface between positive active material and electrolyte, reducing surface oxidizability without adding coating layers that会增加 resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses specific electrolyte compounds as intermediaries to mediate the interface between positive active material and electrolyte. The cyclic carboxylate and chain nitrile compounds act as mediators that form protective interfaces, reducing direct contact reactions while maintaining ion transfer efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If voltage is increased to discharge more energy and increase energy density, then energy density is improved, but surface oxidizability increases and interface relationship deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidsurface oxidizability

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical environment parameters by optimizing electrolyte composition (cyclic carboxylate 12-40 wt%, chain nitrile 0.5-10 wt%) to create a more stable chemical environment that suppresses surface oxidizability even at high voltages, enabling higher energy density without compromising interface stability

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If low-temperature discharge performance is optimized, then low-temperature discharge performance is improved, but high-temperature cycle performance may decline

Engineering Contradiction:

Improvelow-temperature discharge performanceVSAvoidhigh-temperature cycle performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent creates a universal electrolyte composition that performs multiple functions simultaneously: cyclic carboxylate and chain nitrile compounds work together to protect the positive electrode interface (improving high-temperature cycle performance) while chain carbonate and cyclic carbonate maintain ion conductivity (improving low-temperature discharge performance), achieving both goals at once

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances the cycle performance under high voltage and high temperature while improving low-temperature discharge performance, by reducing contact reactions and optimizing lithium ion transfer efficiency.

Implementation Method 1

a positive active material layer disposed on at least one surface of the positive current collector. The positive active material layer includes a positive active material

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

an electrolytic solution... optimized lithium ion transfer efficiency

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS20250118745A1Electrochemical device and electronic device

Publication Date: 2025.04.10 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

An electrochemical device, including a positive electrode, a negative electrode, a separator, and an electrolytic solution. The positive electrode includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector. The positive active material layer includes a positive active material. A volume of the positive active material layer is V1 cm3. A true volume of the positive active material is V2 cm3, and 0.8≤V2/V1≤0.92. The positive active material layer possesses a relatively high packing efficiency and density, and can store more energy under a condition that the volume is constant, and reduce a space in which the electrolytic solution infiltrates the positive active material, thereby reducing reactions between a positive electrode material and the electrolytic solution, improving the cycle performance of the electrochemical device under a high voltage and a high temperature.