Two-Stage Battery Charging with Nitrile Additive

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Solution Overview

Problem

Existing lithium-ion battery charging methods lead to high positive electrode potentials during full charge, causing damage and reducing high-temperature cycle performance and safety, especially due to prolonged high-potential states.

Innovation Solution

A method involving a two-stage charging process with a nitrile compound additive in the electrolytic solution, where the battery is charged at a first-stage current until a first-stage voltage and then at a second-stage current until a higher voltage, with the nitrile compound present at 0.5% to 5% mass percent, to enhance high-temperature cycle performance and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If constant-voltage charging is used to achieve full charge, then the battery reaches full capacity, but the positive electrode potential remains high for a long time causing material damage

Engineering Contradiction:

Improvecharging efficiencyVSAvoidpositive electrode material stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The charging process is divided into two distinct stages: first-stage charging at a first voltage threshold and second-stage charging at a second voltage threshold. This segmentation allows the battery to reach full capacity while limiting the duration of high-potential exposure by transitioning to a lower voltage threshold for the second stage, thereby protecting the positive electrode material from prolonged high-potential damage.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If high charge voltage is applied to maximize capacity, then energy density is improved, but high-temperature storage expansion rate increases

Engineering Contradiction:

Improveenergy densityVSAvoidstorage expansion rate

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The charging method dynamically adjusts the voltage threshold based on the charging stage. By implementing a two-stage charging process with different voltage thresholds, the system optimizes energy density during first-stage charging while protecting against storage expansion during second-stage charging, thus adapting to different charging requirements throughout the process.

Inventive Principle:

Principle #15Dynamics

3Productivity

If prolonged high-potential charging is used to achieve full charge, then charging speed is maintained, but hot-oven safety performance deteriorates

Engineering Contradiction:

Improvecharging speedVSAvoidhot-oven safety

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The method performs preliminary action by establishing a two-stage charging protocol before the damaging high-potential effects can occur. The first-stage charging at a higher voltage threshold quickly charges the battery, while the second-stage charging at a lower voltage threshold prevents the accumulation of harmful high-potential effects, thereby proactively protecting against hot-oven safety issues.

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 effectively reduces high-temperature storage expansion and enhances hot-oven safety performance by shortening the high-potential duration and forming a stable solid electrolyte interphase film, significantly improving battery cycle performance and safety.

Implementation Method 1

forming a stable solid electrolyte interphase film

Methodology Applied

Scientific EffectSolid electrolyte interphase film formation:

Data Source

PatentUS20230117982A1Method for enhancing battery cycle performance and electronic device

Publication Date: 2023.04.20 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

A method for enhancing battery cycle performance is applied in a battery and includes the following steps: charging, at a first stage, the battery at a first-stage current until reaching a first-stage voltage; and charging, at a second stage, the battery at a second-stage current until reaching a second-stage voltage. The second-stage voltage is greater than the first-stage voltage. The second-stage current is less than the first-stage current. The battery includes an electrolytic solution containing an additive. The additive includes a nitrile compound. A mass percent of the nitrile compound in the electrolytic solution is 0.5% to 5%. This application further provides an electronic device. The method and electronic device according to this application can enhance high-temperature cycle performance of the battery, reduce a high-temperature storage expansion rate, and enhance hot-oven safety performance.