Battery Module Bypass and String Isolation for Failsafe Storage
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Solution Overview
Problem
Aerospace battery storage systems face high failure rates due to the failure of a single battery cell in series-connected systems, which can lead to catastrophic failures, and existing solutions do not effectively manage power delivery and balancing without incurring losses or requiring idle times.
Innovation Solution
A battery storage system with multiple modules, each equipped with series and parallel switches for dynamic power management, allowing for the isolation and bypassing of failed modules, and proactive balancing to maintain power delivery and prevent unbalanced states, using inductors for current control and PWM switching to manage power states across modules and strings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery modules are connected in series to increase voltage for high power applications, then power delivery capability is improved, but system reliability deteriorates because a single cell failure causes whole system failure
Solution Approach 1:
The battery system is divided into multiple independent strings, each containing multiple modules connected in series. Each module is further segmented into individual battery cells with independent switching capability. This segmentation allows the system to maintain power delivery through parallel strings while isolating failures to specific modules or cells, preventing single-point failures from cascading throughout the entire system.
Solution Approach 2:
The system dynamically changes the operational state of individual battery cells by switching between connected and isolated states. When a cell fails or requires balancing, its state is changed from connected to isolated, allowing the system to maintain overall functionality by redistributing current through alternative paths while preserving the high voltage configuration needed for power delivery.
2Productivity
If battery modules are kept in connected state to maximize power delivery, then productivity is improved, but loss of energy increases due to inability to balance modules without idle times
Solution Approach 1:
The system enables continuous power delivery to the load while performing balancing operations on battery modules. By isolating individual modules that require balancing rather than taking the entire system offline, the useful action of power delivery continues uninterrupted. The balancing process occurs in parallel with power delivery, eliminating idle times and maintaining continuous productivity.
Solution Approach 2:
The system dynamically adjusts the connection state of individual battery modules in real-time based on their charge levels and operational requirements. Modules can be dynamically isolated for balancing and then reconnected without affecting the overall system operation. This dynamic reconfiguration allows the system to optimize energy distribution continuously while maintaining power delivery, preventing energy losses associated with static configurations.
3Reliability
If switches are added to each battery module for isolation and bypassing capability, then reliability is improved, but device complexity increases
Solution Approach 1:
The switches integrated into each battery module serve multiple functions: they enable isolation of failed cells, facilitate balancing operations, and provide bypass paths for current flow. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in device complexity while achieving enhanced reliability through improved failure tolerance and operational flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system maintains high reliability and power delivery even with module failures, reduces power degradation, and prevents unbalanced states without idle times or losses, ensuring continued operation and extended lifespan by dynamically managing power states and module usage.
Implementation Method 1
A string may include an inductor and/or a diode to improve current distribution and/or to avoid unwanted currents flowing between strings. An inductor may improve current control of a string as the current may be controlled by pulse width modulation (PWM) switching between the connected and open states of a string.
Implementation Method 2
A string may include an inductor and/or a diode to improve current distribution and/or to avoid unwanted currents flowing between strings.
Data Source
AI summary
A failsafe battery storage system contains a plurality of strings of battery modules. Within each string, the battery modules are connected in series and the strings are connected in parallel. Over multiple periods of time different combinations of battery modules are in a connected state with batteries connected, while the remaining battery modules are in a bypass state such that battery modules with a higher power state have longer times in a connected state than battery modules with a lower power state. Further, over multiple periods of time different combinations of strings are in a connected state, while the remaining strings are in an open state, such that strings with a higher power state of their battery modules have longer times in a connected state than strings with a lower power state. The discussed storage system puts failed battery modules into a bypass state and/or failed strings of battery modules into an open state.