Dynamic Demand Threshold Optimization for Battery Lifetime

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Solution Overview

Problem

Conventional energy management systems fail to effectively reduce peak demand charges while maximizing the usable lifetime of energy storage systems, as they often rely on fixed thresholds that lead to battery degradation and increased costs.

Innovation Solution

A method that determines a dynamic monthly demand threshold using mixed-integer linear programming to minimize peak demand charges and extend the battery's lifetime by optimizing the split between power drawn from the electrical grid and the energy storage system, based on load profiles and demand charge rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a fixed threshold is set for user load and the energy storage system discharges when the load exceeds this threshold, then peak demand charges are reduced, but the battery capacity diminishes and the battery's useful lifetime is shortened

Engineering Contradiction:
Improvepeak demand chargesVSAvoidbattery useful lifetime
Core Design Contradiction:
Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The patent applies dynamics by transitioning from a fixed threshold to a dynamic, adaptive threshold that changes based on battery state of charge, time of day, and predicted load patterns. The threshold is continuously adjusted to optimize both peak demand charge reduction and battery lifetime extension, allowing the system to respond flexibly to varying conditions rather than following a rigid fixed threshold approach.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the discharge threshold parameter dynamically based on multiple factors including battery state of charge, time of day, seasonal variations, and predicted load patterns. This allows the system to adapt the discharge behavior to current conditions, optimizing the balance between reducing peak charges and preserving battery lifetime through intelligent parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the energy storage system maintains a high state of charge with large battery throughput, then peak demand charges are minimized, but the battery capacity diminishes rapidly

Engineering Contradiction:
Improvepeak demand chargesVSAvoidbattery capacity
Core Design Contradiction:
Loss of energyVSQuantity of substance

Solution Approach 1:

The patent applies partial action by discharging the battery only when necessary and beneficial, rather than maintaining constantly high throughput. The system intelligently determines when discharge should occur based on predicted peak periods and current state of charge, avoiding unnecessary discharge cycles that would degrade battery capacity while still achieving sufficient peak charge reduction.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system uses feedback mechanisms by continuously monitoring battery state of charge, discharge cycle history, and performance metrics to adjust discharge behavior. This feedback loop allows the system to learn from past performance and optimize future discharge decisions, balancing peak charge reduction with battery capacity preservation through adaptive control based on real-time and historical data.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS10511179B2Energy storage-aware demand charge minimization
Publication Date: 2019.12.17 NEC CORP
  • US10511179B2 patent drawing
  • US10511179B2 patent drawing
  • US10511179B2 patent drawing

AI summary

Systems and methods for power management include determining a demand threshold by solving an optimization problem that minimizes peak demand charges and maximizes a usable lifetime for a power storage system. Power is provided to a load from an electrical grid when the load is below the demand threshold and from a combination of the electrical grid and the power storage system when the load is above the demand threshold.