Blended Cathode Voltage Estimation via Circuit Segmentation

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Solution Overview

Problem

Existing secondary battery technologies face challenges in accurately estimating voltage, particularly when using blended cathode materials with distinct voltage behaviors, which complicates charge/discharge control and requires precise interpretation of voltage patterns.

Innovation Solution

A voltage estimating apparatus and method that utilize a blended cathode material comprising at least two cathode materials with different operating voltage ranges, coupled with a control unit and sensor to measure current and voltage, and a circuit model to calculate the estimated voltage by integrating currents and voltages through separate cathode and anode material circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If blended cathode materials with different operating voltage ranges are used, then energy capacity and high-temperature stability are improved, but voltage estimation accuracy deteriorates due to complex voltage behavior

Engineering Contradiction:
Improveenergy capacityVSAvoidvoltage estimation accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent divides the voltage estimation problem into two separate estimations: one for the first cathode material and another for the second cathode material. Each material's voltage is estimated independently using its own equivalent circuit model, then the results are combined. This segmentation allows accurate tracking of each material's contribution to the total voltage despite their different operating voltage ranges and complex interactions.

Inventive Principle:
Principle #1Segmentation

2Reliability

If blended cathode materials are used to supplement weaknesses, then reliability is improved, but device complexity increases due to multiple cathode materials

Engineering Contradiction:
Improvehigh-temperature stabilityVSAvoidcathode material composition
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite cathode materials consisting of two distinct cathode materials with complementary properties. The first cathode material provides high energy capacity while the second cathode material provides high-temperature stability. By combining these materials in a blended cathode structure, the system achieves both high energy capacity and high-temperature stability, resolving the contradiction between reliability improvement and material complexity through purposeful composite design.

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If separate equivalent circuit models are used for each cathode material, then voltage estimation accuracy is improved, but calculation complexity increases

Engineering Contradiction:
Improvevoltage estimation accuracyVSAvoidcalculation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges two separate equivalent circuit models into a unified blended cathode equivalent circuit model. The first equivalent circuit model represents the first cathode material, and the second equivalent circuit model represents the second cathode material. These are combined in a way that allows independent voltage estimation for each material while maintaining a unified calculation framework. This merging approach enables accurate voltage estimation without requiring completely separate calculation systems, thus managing calculation complexity while maintaining precision.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables reliable voltage estimation in secondary batteries with blended cathode materials, allowing for optimized blending ratios and improved performance in electric vehicles and power storage devices, even in voltage ranges with complex behavior.

Implementation Method 1

A battery generates electric energy by oxidation and reduction reactions

Methodology Applied
Scientific EffectOxidation and reduction reactions: Redox Reactions

Implementation Method 2

an electrolyte allowing the transfer of operating ions between the anode and the cathode

Methodology Applied
Scientific EffectIon transfer: Ion Exchange

Data Source

PatentEP3136118B1Apparatus and method for estimating voltage of secondary battery including blended cathode material
Publication Date: 2018.01.31 LG CHEM LTD
  • EP3136118B1 patent drawingFigure 1~2
  • EP3136118B1 patent drawingFigure 3~4
  • EP3136118B1 patent drawingFigure 5~6

AI summary

Disclosed is an apparatus for estimating a voltage of a secondary battery which includes a cathode comprising a first cathode material and a second cathode material with different operating voltage ranges, an anode comprising an anode material and a separator for separating the cathode from the anode. The apparatus comprises a control unit configured to estimate a voltage of a secondary battery based on a circuit model including a first cathode material circuit, a second cathode material circuit and an anode material circuit, each circuit being modeled to change its voltage according to State Of Charge (SOC) of the electrode material corresponding the circuit and a current flowing through the circuit.