Dynamic SOC Window Control for Battery Wear Reduction

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Solution Overview

Problem

Energy storage systems, particularly batteries, face inefficiencies and faster degradation due to overperformance at the beginning of life, leading to higher cycle rates and unnecessary wear, which results in higher operating costs and reduced lifespan.

Innovation Solution

Implementing a method to control performance parameters of energy storage devices by adjusting operating values to maintain minimum necessary levels, reducing charge and discharge cycles, and optimizing state of charge windows, temperature, and other parameters to extend battery life and improve efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If batteries are sized with 20-50% more capacity at BOL than needed, then they have enough capacity at EOL, but this results in overperformance and excess device wear without compensation

Engineering Contradiction:
Improvebattery capacity sufficiency at EOLVSAvoidexcess device wear and overperformance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the state of charge (SOC) window based on battery age. At BOL, it uses a narrower SOC window (e.g., 40-60%) to reduce wear, and gradually expands it as the battery ages. This dynamic adaptation resolves the contradiction by preventing overperformance wear early in life while ensuring sufficient capacity utilization later when degradation has occurred.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operating parameters (SOC window boundaries) based on battery lifecycle stage. By monitoring cycle count and adjusting the SOC window accordingly, the system optimizes the balance between reliability and wear prevention. The SOC window is a key parameter that is modified to resolve the contradiction between having excess capacity and avoiding unnecessary wear.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If batteries cycle through more MWh per day at BOL, then performance score is higher, but the battery system is not paid for that higher score and gives away performance without compensation

Engineering Contradiction:
Improveperformance score and MWh cyclingVSAvoiduncompensated performance degradation
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The system intentionally limits the battery's action (cycling) to a partial level by using a narrower SOC window at BOL. Instead of cycling through the full available capacity, it uses only a portion (e.g., 40-60% SOC range), thereby reducing uncompensated wear while still providing sufficient performance for grid services. This resolves the contradiction by avoiding excessive action that leads to uncompensated degradation.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If batteries are designed for frequency stabilization applications, then they can deliver constant active and reactive power, but this requires larger capacity to account for degradation over time

Engineering Contradiction:
Improvefrequency stabilization performanceVSAvoidbattery capacity and system size
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system dynamically optimizes capacity utilization by adjusting the SOC window based on age. This allows the same physical battery capacity to provide reliable frequency stabilization service throughout its lifecycle without requiring excessive initial oversizing. The dynamic adjustment ensures that the battery operates within safe limits early on while maximizing utilization later, resolving the contradiction between reliability and quantity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3261211B1Systems and methods for controlling performance parameters of an energy storage device
Publication Date: 2019.10.23 GENERAL ELECTRIC CO
  • EP3261211B1 patent drawingFigure 1~2
  • EP3261211B1 patent drawingFigure 3~4
  • EP3261211B1 patent drawingFigure 5

AI summary

Systems and methods 150 for controlling performance parameters for an energy storage device 108 include providing 152 primary control signals to an energy storage device 108 that indicate at least one operating value in a range defined by at least one set point value for one or more performance parameters of the energy storage device 108. In one embodiment, an actual performance score for the energy storage device operated in accordance with the primary control signals is determined 152 and compared with a required performance score to determine a performance score evaluation parameter 154. Additional control signals are then determined 156 and provided to the energy storage device 108 in a manner that adjusts the at least one operating value of the one or more primary control signals relative to the at least one set point value for the one or more performance parameters based at least in part on the performance score evaluation parameter.