Blended Cathode Voltage Relaxation for Battery Management

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Solution Overview

Problem

Lithium secondary batteries face challenges in achieving low production costs and high energy capacity while maintaining high-temperature stability, particularly due to limitations in the electrochemical reaction mechanisms of individual cathode materials.

Innovation Solution

A blended cathode material is introduced, comprising at least two different cathode materials with distinct operating voltage ranges, allowing for voltage relaxation by transferring operating ions between them when the battery is in an idle or no-load state, which enhances electrochemical performance and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single cathode material is used, then the battery structure is simple and manufacturing is easier, but the energy capacity and high-temperature stability are limited

Engineering Contradiction:
Improveenergy capacityVSAvoidcathode material composition
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies composite materials by blending multiple cathode materials (e.g., LiCoO2, LiMn2O4, LiFePO4) in specific ratios to create a cathode composite that achieves synergistic effects. This composite structure enables the battery to attain higher energy capacity and improved high-temperature stability that cannot be achieved with single cathode materials, while the blending approach provides a practical pathway to resolve the complexity issue through established manufacturing techniques.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple cathode materials are blended, then the energy capacity and stability are improved, but the electrochemical reaction mechanism becomes complex and difficult to predict

Engineering Contradiction:
Improvehigh-temperature stabilityVSAvoidelectrochemical reaction mechanism
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies segmentation by dividing the cathode into multiple distinct material phases, each with well-defined electrochemical characteristics and operating voltage ranges. This segmentation allows the complex blended cathode system to be understood as a collection of simpler, individual components whose behaviors can be independently characterized and then integrated. The voltage relaxation phenomenon serves as a natural indicator that helps segment and identify the contribution of each cathode material phase during battery operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by utilizing the voltage relaxation phenomenon as a measurable parameter that changes in response to the electrochemical states of different cathode materials. By monitoring voltage relaxation behavior, the system can infer the state of charge and electrochemical reactions occurring in each cathode material phase, thereby simplifying the detection and measurement of the overall electrochemical reaction mechanism in blended cathodes.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If cathode materials with different operating voltage ranges are used, then voltage relaxation occurs improving performance, but the charge-discharge control becomes more difficult

Engineering Contradiction:
Improvecharge-discharge efficiencyVSAvoidvoltage control
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent applies feedback by utilizing the voltage relaxation phenomenon as a real-time indicator of the electrochemical state of blended cathode materials. The voltage relaxation behavior provides feedback information about the state of charge and reaction progress in each cathode material phase, enabling the battery management system to adjust charge-discharge control strategies dynamically. This feedback mechanism simplifies the control of batteries with multiple cathode materials by providing natural, measurable signals that reflect the internal electrochemical state.

Inventive Principle:
Principle #23Feedback

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 blended cathode material enables reliable prediction of electrochemical behaviors and improves the battery's energy capacity and stability, allowing for more efficient charge and discharge cycles.

Implementation Method 1

allow voltage relaxation by transferring the operating ions between the first and second cathode materials when coming to an idle state or a no-load state in an intrinsic voltage range

Methodology Applied
Scientific EffectIon transfer: Ion Exchange

Implementation Method 2

The electrochemical reaction includes oxidation and reduction reactions of the first and second cathode materials accompanied with charging or discharging of the secondary battery

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Implementation Method 3

intercalating and deintercalating reactions of lithium ions occur at a cathode and an anode, respectively. During discharge, lithium ions are deintercalated from the anode material, transferred to the cathode through an electrolyte, and intercalated into the cathode material

Methodology Applied
Scientific EffectIntercalation: Absorption (physical)

Data Source

PatentEP3255444B1Method for managing a secondary battery
Publication Date: 2020.01.08 LG CHEM LTD
  • EP3255444B1 patent drawingFigure 1~2
  • EP3255444B1 patent drawingFigure 3
  • EP3255444B1 patent drawingFigure 4

AI summary

Disclosed is a battery system for a secondary battery including a blended cathode material, and an apparatus and method for managing a secondary battery having a blended cathode material. The blended cathode material includes at least a first cathode material and a second cathode material. The first and second cathode materials have different operating voltage ranges. When the secondary battery comes to an idle state or a no-load state, the battery system detects a voltage relaxation occurring by the transfer of operating ions between the first and second cathode materials.