Sodium-Sulfur Battery Depth of Discharge Correction via Weather Data

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Solution Overview

Problem

In small-scale interconnected systems combining renewable energy power generation devices with sodium-sulfur batteries for power compensation, there is a discrepancy between the actual and managed depth of discharge of the sodium-sulfur battery due to slight errors in current control, leading to potential sudden inability to charge or discharge, disrupting output fluctuations compensation.

Innovation Solution

Determine a time within a predetermined period based on weather and seasonal information to correct or reset the depth of discharge of the sodium-sulfur battery, setting output target values to lead the battery to charge or discharge ends, allowing for accurate management and eliminating discrepancies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the depth of discharge is managed by integrating current values in the control device, then the management value can be calculated continuously, but slight errors in current control accumulate over time causing discrepancy between actual and managed depth of discharge

Engineering Contradiction:
Improvecontinuous management capabilityVSAvoiddepth of discharge accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements periodic correction of the depth of discharge management value by detecting charge/discharge end states and resetting the management value to match the actual state. This periodic intervention prevents error accumulation while maintaining continuous management capability between corrections.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses feedback from charge/discharge end detection to correct the management value. When the battery reaches charge or discharge ends, the system detects this state and uses it as feedback to reset the management value, eliminating the discrepancy caused by integration errors.

Inventive Principle:
Principle #23Feedback

2Duration of action of stationary object

If the interconnected system operates over a long period, then power compensation capability is maintained, but discrepancy between actual and managed depth of discharge inevitably occurs

Engineering Contradiction:
Improveoperation durationVSAvoiddepth of discharge management reliability
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The system performs preliminary detection of charge/discharge end states and proactively corrects the management value before significant discrepancies accumulate. This preliminary action maintains management reliability throughout long-term operation by preventing error buildup.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The periodic correction mechanism acts as a cushioning measure that prevents the accumulation of management errors during long-term operation. By resetting the management value at charge/discharge ends, the system cushions against the inevitable drift that would otherwise occur over extended periods.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Measurement precision

If the sodium-sulfur battery reaches charge or discharge ends frequently, then the management value can be corrected often, but the battery availability for power compensation is reduced

Engineering Contradiction:
Improvemanagement value accuracyVSAvoidbattery availability
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system uses the battery's own charge/discharge end states as the triggering mechanism for correction. Rather than forcing the battery into artificial charge/discharge cycles solely for correction purposes, the system waits for the battery to naturally reach its operational boundaries, thereby correcting the management value without additional productivity loss.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2339685B1Method for controlling sodium-sulfur battery
Publication Date: 2014.11.12 NGK INSULATORS LTD
  • EP2339685B1 patent drawingFigure 1
  • EP2339685B1 patent drawingFigure 2
  • EP2339685B1 patent drawingFigure 3~4

AI summary

In a method for controlling a sodium-sulfur battery, a time of correcting or resetting a depth of discharge of the sodium-sulfur battery is determined within a predetermined period based on weather information, and the depth of discharge of the sodium-sulfur battery is corrected or reset in the determined time. According to this sodium-sulfur battery control method, the depth of discharge of the sodium-sulfur battery can be accurately managed in a small-scale interconnected system.