Secondary Battery Control via Electrode Potential Monitoring

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Solution Overview

Problem

Existing secondary battery control methods fail to effectively suppress side reactions by monitoring voltage rather than electrode potentials, leading to potential overcharge and overdischarge issues.

Innovation Solution

A control apparatus and method that monitor and control the positive and negative electrode potentials within set limits, using resistance components to correct open circuit potentials and prevent side reactions by adjusting charge and discharge rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If voltage monitoring is used to control charge and discharge, then the control system is simple to implement, but side reactions cannot be effectively suppressed

Engineering Contradiction:
Improvecontrol system simplicityVSAvoidside reaction suppression
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention changes the monitoring parameter from voltage to electrode potential. By measuring the potential of each electrode relative to a reference electrode, the system can directly monitor the electrochemical state that causes side reactions, thereby improving reliability while maintaining operational simplicity through the use of a straightforward potential measurement system.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces a reference electrode as an intermediary to measure the potential of each electrode. This reference electrode serves as a stable baseline, allowing the system to accurately determine the potential difference between electrodes and the reference, enabling effective side reaction suppression without complex control mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If electrode potential monitoring is implemented, then side reactions can be suppressed, but the device complexity increases

Engineering Contradiction:
Improveside reaction suppressionVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A single reference electrode is introduced as an intermediary measurement point. This reference electrode provides a stable potential baseline against which both the positive and negative electrode potentials can be measured. This approach achieves accurate electrode potential monitoring without requiring multiple complex measurement systems, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The reference electrode serves multiple functions simultaneously: it provides a stable potential reference for measuring both electrode potentials, enables calculation of cell voltage, and facilitates monitoring of both charging and discharging states. This multi-functionality reduces the need for separate measurement systems, thereby limiting complexity increase.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If voltage-based control is used, then the control method is simple, but overcharge and overdischarge protection is insufficient

Engineering Contradiction:
Improvecontrol method simplicityVSAvoidovercharge and overdischarge protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control method changes from voltage-based to potential-based monitoring. By measuring the potential of each electrode relative to a reference electrode, the system can directly detect the electrochemical state that precedes overcharge and overdischarge conditions, enabling more accurate and timely protection while maintaining control simplicity through straightforward potential comparison with threshold values.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2804249B1Method for controlling and device for controlling secondary battery
Publication Date: 2017.08.30 TOYOTA JIDOSHA KK
  • EP2804249B1 patent drawingFigure 1
  • EP2804249B1 patent drawingFigure 2
  • EP2804249B1 patent drawingFigure 3

AI summary

[PROBLEM] To suppress a side reaction of a secondary battery associated with a positive electrode potential and a negative electrode potential. [SOLVING MEANS] A control apparatus has a controller configured to control charge and discharge of a secondary battery. The controller acquires a positive electrode potential and a negative electrode potential of the secondary battery. The controller controls the charge and discharge of the secondary battery such that each of the positive electrode potential and the negative electrode potential changes within a range between an upper limit value and a lower limit value set for each of the positive electrode potential and the negative electrode potential.