Parallel Battery Branch Current Balancing With a DC/DC Converter
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Solution Overview
Problem
In energy storage systems, direct parallel connection of battery clusters leads to circulating currents and uneven charging/discharging, causing capacity loss and potential irreversible damage due to unbalanced current sharing.
Innovation Solution
Incorporating a DC/DC converter in one energy storage branch to adjust its output current, allowing for balanced current sharing between branches, thereby maximizing system capacity while minimizing cost and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If battery clusters are directly connected in parallel to increase capacity, then the energy storage capacity increases, but circulating currents occur between clusters causing uneven charging/discharging and potential battery damage
Solution Approach 1:
A DC/DC converter is introduced as an intermediary device between parallel-connected battery clusters. The converter regulates current flow between clusters, preventing circulating currents while enabling balanced charging and discharging. This mediator allows capacity expansion through parallel connection without the harmful effects of direct connection.
Solution Approach 2:
The DC/DC converter dynamically adjusts electrical parameters (voltage and current) between battery clusters to maintain balanced operation. By changing these parameters in real-time based on cluster states, the system prevents circulating currents while maximizing energy storage capacity through parallel configuration.
2Reliability
If DC/DC converters are added to balance current between branches, then current sharing and capacity are improved, but system cost and volume increase
Solution Approach 1:
The system divides battery clusters into separate energy storage branches with independent control. Each branch can be managed independently by DC/DC converters, allowing selective placement of converters only where needed to balance current, rather than requiring converters in all branches or throughout the entire system.
Solution Approach 2:
The DC/DC converter provides dynamic current regulation capability, adjusting output current in real-time to balance charging and discharging between branches. This dynamic control enables reliable current sharing without requiring static structural modifications or additional converters in every branch, thus controlling system complexity.
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 solution enables balanced charging and discharging across branches, increasing energy storage system capacity, reducing power loss, and lowering system volume and cost by ensuring synchronized operation of battery clusters.
Implementation Method 1
a first DC/DC converter, an output end of the first DC/DC converter being connected in series to the second battery cluster, the first DC/DC converter being configured for adjusting an output current of the second energy storage branch
Data Source
AI summary
An energy storage system includes a first energy storage branch and a second energy storage branch connected in parallel. The first energy storage branch includes a first battery cluster. The second energy storage branch includes a second battery cluster and a DC/DC converter connected to the second battery cluster in series, with an output end of the DC/DC converter being connected to the second battery cluster. The DC/DC converter is configured to adjust an output current of the second energy storage branch to balance an output current of the first energy storage branch and the output current of the second energy storage branch.