Battery Circuit Voltage Balancing Across Parallel Bridge Arms
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Solution Overview
Problem
Battery assemblies experience inconsistent charging and discharging due to differences in initial capacity, equivalent series internal resistance, temperature, and voltage among cells, leading to over-charging or over-discharging, which reduces capacity, safety, and service life.
Innovation Solution
A battery circuit with an energy storage unit and processing unit that controls the connection of cells to ensure they have the same rated voltage, using switches to balance voltages across cells and bridge arms, allowing for parallel and serial connections to achieve voltage balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cells are connected in series and parallel to form battery assembly to meet high power requirements, then power capability is improved, but voltage inconsistency among cells causes over-charging or over-discharging
Solution Approach 1:
The battery assembly is divided into multiple bridge arms, with each bridge arm containing multiple cells. This segmentation allows independent voltage balancing control for each bridge arm, addressing the voltage inconsistency problem while maintaining the high power capability provided by the series-parallel configuration.
Solution Approach 2:
An energy storage unit is introduced as an intermediary component between the battery assembly and the external circuit. This energy storage unit enables voltage balancing by storing excess energy from cells with higher voltage and releasing it to cells with lower voltage, thereby resolving the voltage inconsistency without compromising the overall power output.
2Reliability
If voltage balancing is implemented using energy storage unit and processing unit, then voltage consistency is improved, but device complexity increases
Solution Approach 1:
The energy storage unit serves multiple functions: it acts as both an energy buffer for voltage balancing and as part of the power delivery system. The processing unit simultaneously manages switching control and voltage monitoring. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity.
Solution Approach 2:
The system employs dynamic switching control where the processing unit adjusts the connection states of switches in real-time based on voltage measurements. This dynamic approach allows voltage balancing to be achieved adaptively without requiring a permanently complex circuit structure, as the complexity is activated only when needed.
3Productivity
If inconsistent charging and discharging occurs due to manufacturing differences, then initial capacity utilization is improved, but service life is reduced
Solution Approach 1:
The system performs preliminary voltage measurement and comparison among all cells before charging or discharging operations. The processing unit identifies cells with abnormal voltages in advance and adjusts the charging/discharging strategy accordingly. This preliminary action prevents over-charging or over-discharging that would otherwise occur due to manufacturing differences, thereby extending service life while maintaining capacity utilization.
Solution Approach 2:
The system continuously monitors the voltage of each cell and provides feedback to the processing unit, which adjusts the switching control in real-time. This feedback mechanism ensures that cells with lower capacity or higher internal resistance are protected from over-charging or over-discharging, allowing the battery assembly to fully utilize the capacity of weaker cells without compromising their longevity.
Data Source
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AI summary
The present disclosure relates to the technical field of batteries, and discloses a battery circuit, a control method for a battery circuit, a device, and a medium. The battery circuit includes: an energy storage unit, at least one battery assembly, and a processing unit. For each battery assembly, the battery assembly is connected parallelly to two terminals of the energy storage unit, and the battery assembly includes a first bridge arm, where the first bridge arm includes at least two serially connected first cells. The processing unit is connected to a control terminal of the energy storage unit and a control terminal of each first bridge arm, and configured to control at least one first cell in at least one first bridge arm to connect to the energy storage unit, where different first cells have the same rated voltage. The battery circuit provides a hardware basis for the voltage balancing of cells.