Energy Storage Module Selection by State of Charge and Temperature
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Solution Overview
Problem
Energy storage devices, such as batteries, face inefficiencies due to varying state of charge and ageing among individual modules, leading to uneven stress and reduced service life, as they are typically selected based solely on current state of charge without considering additional operating parameters.
Innovation Solution
An electric energy storage device with a control system that assesses the state of charge and further operating parameters of each module to calculate and select the required number of modules for series connection, optimizing their usage and extending their service life by prioritizing modules based on factors like remaining service life, temperature, and voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If modules are selected based solely on current state of charge, then the selection process is simple, but the service life of individual modules varies and efficiency is reduced
Solution Approach 1:
The patent extends the selection criteria from a single parameter (state of charge) to multiple parameters including state of charge, temperature, and cycle count. This multi-parameter approach allows the system to balance simplicity with improved reliability by considering additional factors that affect module longevity without making the selection process overly complex.
Solution Approach 2:
The selection strategy is made dynamic by continuously monitoring multiple parameters and adjusting module selection based on their current state. Modules are rotated in and out of service based on their accumulated stress, temperature exposure, and charge state, creating a dynamic balancing act that extends overall system life while maintaining operational simplicity.
2Device complexity
If all modules are used continuously, then the device complexity is reduced, but individual modules experience uneven stress and reduced service life
Solution Approach 1:
The patent divides the battery system into individually monitorable and selectable modules, each tracked for its own state of charge, temperature, and cycle count. This segmentation allows the control system to manage modules differently based on their individual conditions, extending service life through selective usage while maintaining relatively simple overall device architecture.
Solution Approach 2:
Modules are temporarily taken out of service (discarded from active duty) when they reach certain stress thresholds, allowing them to rest and recover. The system rotates modules in and out of active service based on their condition, effectively recovering their capacity and extending their usable life before permanent replacement is needed.
3Reliability
If modules with higher remaining service life are prioritized, then immediate reliability is improved, but modules with lower remaining life are overstressed and fail sooner
Solution Approach 1:
The system implements periodic rotation of modules through active and inactive states. Rather than permanently prioritizing certain modules, the system cycles modules in and out of service based on their current condition, ensuring that no single module is continuously overstressed while maintaining reliable operation through adequate module availability.
Solution Approach 2:
The control system continuously monitors module parameters (state of charge, temperature, cycle count) and uses this feedback to dynamically adjust which modules are active. This closed-loop control ensures that modules approaching stress thresholds are rotated out, preventing failure while maintaining optimal system reliability through informed decision-making.
Data Source
AI summary
The invention relates to an energy storage device and a method for operating an energy storage device comprising a plurality of energy storage modules. In order to adjust the output voltage to the energy storage device, one or more energy storage modules is/are connected in series. According to the invention, the series-connected energy storage modules are selected in accordance with the state of charge and at least one other operating parameter in order to be able to use the individual energy storage modules in a particularly efficient manner.