Battery Life Model Controller for Grid Energy Storage

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Solution Overview

Problem

Conventional ramp rate control and frequency regulation techniques for stabilizing energy grids with intermittent solar power sources, such as photovoltaic fields, often conflict and lead to premature battery degradation, failing to maintain battery state-of-charge within acceptable ranges.

Innovation Solution

An electrical energy storage system with a controller using a battery life model to generate optimal power setpoints for both frequency regulation and ramp rate control, considering variables like temperature, state-of-charge, and power ratios, to estimate degradation and revenue, thereby balancing battery usage and revenue generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional ramp rate control and frequency regulation techniques are used simultaneously, then grid stability is improved, but battery degradation accelerates and state-of-charge control fails

Engineering Contradiction:

Improvegrid stabilityVSAvoidbattery life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The system dynamically adjusts battery power setpoints by changing operational parameters (power levels, charge/discharge rates) based on real-time conditions including grid frequency deviations and PV ramp rates. This allows the battery to operate within safe parameter ranges that prevent degradation while effectively providing both ramp rate control and frequency regulation services to maintain grid stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The controller continuously monitors battery state-of-charge, power output, and grid conditions, then adjusts power setpoints based on this feedback. The system uses feedback loops to ensure state-of-charge remains within acceptable ranges while coordinating ramp rate control and frequency regulation actions, preventing battery degradation through adaptive control based on real-time system state.

Inventive Principle:

Principle #23Feedback

2Reliability

If battery power setpoints are increased to improve frequency regulation performance, then grid frequency stability is improved, but battery degradation accelerates

Engineering Contradiction:

Improvefrequency regulation performanceVSAvoidbattery degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system employs dynamic power setpoint adjustment rather than static operating points. Power setpoints are continuously adapted based on grid frequency deviations, battery state-of-charge, and PV ramp rate conditions. This dynamic approach allows the battery to provide effective frequency regulation when needed while reducing power levels during periods of low grid stress, thereby preventing excessive degradation from sustained high-power operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller implements periodic assessment and adjustment of power setpoints based on changing grid conditions and battery state. By alternating between active regulation periods and rest periods, the system provides frequency regulation services when required while allowing the battery to recover and avoid continuous high-stress operation that would accelerate degradation.

Inventive Principle:

Principle #19Periodic action

3Measurement precision

If aggressive battery control is used to maintain state-of-charge within narrow ranges, then state-of-charge control precision is improved, but battery flexibility for simultaneous ramp rate control and frequency regulation is reduced

Engineering Contradiction:

Improvestate-of-charge control precisionVSAvoidbattery operational flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The battery control system is designed to perform multiple functions simultaneously: ramp rate control, frequency regulation, and state-of-charge management. The unified controller coordinates these competing objectives by calculating power setpoints that satisfy all three requirements, allowing the single battery asset to provide diverse grid services while maintaining state-of-charge within acceptable ranges through integrated multi-objective optimization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11296511B2Energy storage controller with battery life model

Publication Date: 2022.04.05 CON EDISON BATTERY STORAGE LLC

AI summary

An electrical energy storage system includes a battery configured to store and discharge electric power to an energy grid, a power inverter configured to use battery power setpoints to control an amount of the electric power stored or discharged from the battery, the battery power setpoints comprising at least one of frequency regulation power setpoints and ramp rate control power setpoints, and a controller. The controller is configured to use a battery life model to generate the battery power setpoints for the power inverter. The battery life model includes one or more variables that depend on the battery power setpoints.