Battery Pack Equalization Circuit Using a Resonant Energy Bus
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Solution Overview
Problem
In energy storage systems, battery packs connected in series develop varying states of charge over time due to manufacturing differences and usage environments, leading to inefficient charging and discharging, where some packs have surplus energy that cannot be released or charged, affecting the overall efficiency of the system.
Innovation Solution
An equalization circuit with a transformer, bridge resonant circuit, and bridge circuit is used to connect battery packs to an equalization bus, allowing energy transfer between packs to equalize their states of charge, utilizing switch transistors and resonant components for efficient power conversion and isolation, thereby ensuring all packs are fully charged or discharged simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If battery packs are connected in series to increase voltage and capacity, then the energy storage capability is improved, but the uniformity of states of charge deteriorates due to manufacturing differences and usage environments
Solution Approach 1:
The patent divides the battery system into independent battery packs, each with its own equalization circuit. This segmentation allows individual monitoring and equalization of each pack's state of charge, addressing the uniformity issue while maintaining the series connection for high voltage and capacity.
Solution Approach 2:
The patent introduces an equalization bus as an intermediary component that facilitates energy transfer between battery packs. This mediator enables charge redistribution from packs with higher SOC to packs with lower SOC, resolving the non-uniformity problem while preserving the series connection architecture.
2Stability of the object's composition
If traditional equalization methods are used between battery packs, then energy uniformity is improved, but system complexity increases due to multiple multi-level equalization circuits
Solution Approach 1:
The patent designs a universal equalization bus that can serve multiple battery packs simultaneously. This single multi-functional bus replaces what would otherwise require multiple separate equalization circuits, reducing system complexity while maintaining equalization capability across all packs.
Solution Approach 2:
The patent combines multiple equalization functions into a single integrated equalization bus structure. By merging the equalization paths of different battery packs through this common bus, the system achieves simplified architecture compared to having individual equalization circuits for each pack pair.
3Productivity
If battery packs with different SOCs are charged/discharged simultaneously, then charging/discharging speed is improved, but energy utilization deteriorates due to surplus energy that cannot be released or stored
Solution Approach 1:
The patent implements a feedback mechanism where the equalization bus continuously monitors and adjusts energy flow between battery packs based on their respective states of charge. This feedback control enables real-time optimization of energy distribution, ensuring high energy utilization while maintaining fast charging/discharging operations.
Solution Approach 2:
The patent enables battery packs to self-equalize through the equalization bus without requiring external intervention. Packs with surplus energy automatically transfer charge to packs needing charge, allowing the system to self-correct SOC imbalances and maximize energy utilization during simultaneous charging/discharging operations.
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
This solution ensures that all battery packs in the energy storage system are uniformly charged or discharged, improving the overall efficiency of the energy storage system by eliminating the need for external energy and simplifying the system architecture, while also providing fault isolation and flexible equalization strategies.
Implementation Method 1
a transformer, a bridge resonant circuit, a bridge circuit... The first end is connected to a primary-side winding of the transformer through the bridge resonant circuit. The second end is connected to a secondary-side winding of the transformer through the bridge circuit
Implementation Method 2
The bridge resonant circuit includes a resonant inductor and at least one bridge arm... utilizing switch transistors and resonant components for efficient power conversion
Data Source
AI summary
Examples of an equalization circuit, a battery pack, and an energy storage system are described. In one example, an equalization circuit is configured to: when a difference between a state of charge (SOC) of a battery pack and an SOC or SOCs of any one or more other battery packs exceeds an equalization threshold, by turning on or off switch transistors of a bridge resonant circuit and a bridge circuit, receive, through an equalization bus, discharge power of the one or more other battery packs, and input charge power to the battery pack; or receive discharge power output by the battery pack, and output, to the equalization bus, charge power for inputting to the one or more other battery packs, so that uniformity between SOCs of the battery packs can be flexibly adjusted.