Battery Module DC/DC Control for Series Voltage Consistency
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Solution Overview
Problem
Large-scale battery energy storage systems face inefficiencies due to voltage limitations of individual battery modules, leading to inconsistent charging and discharging, reduced utilization rates, and waste from derating, as well as increased costs and complexity from high boost ratios in DC/DC converters.
Innovation Solution
An energy storage system with a centralized monitoring system and DC/DC or DC/AC converters that manage energy storage modules in series or parallel configurations, ensuring consistent energy storage element parameters across modules through compensation currents, enhancing control flexibility and management effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery modules are connected in series to increase voltage for large-scale energy storage, then voltage requirement is met, but inconsistency between battery modules increases leading to derating and waste
Solution Approach 1:
The patent divides the battery system into multiple battery clusters, each with its own DC/DC converter. This segmentation allows independent control of each cluster, enabling consistent charging/discharging rates across modules while achieving high voltage through series connection within clusters. The segmentation resolves the contradiction by allowing voltage multiplication without sacrificing module consistency.
Solution Approach 2:
The patent introduces DC/DC converters as intermediary devices between battery clusters and the grid. These converters act as mediators that can independently regulate charging and discharging rates for each cluster, ensuring consistency among series-connected modules while achieving the required voltage level. The intermediary device enables both high voltage and consistent operation.
2Device complexity
If simple parallel connection of battery clusters is used, then system complexity is reduced, but inconsistent charging and discharging occurs due to different internal resistances and port voltages
Solution Approach 1:
The patent employs dynamic control through DC/DC converters that can adjust charging and discharging rates in real-time based on the state of each battery cluster. This dynamic adjustment ensures consistent operation despite differences in internal resistance and port voltage, while maintaining a relatively simple parallel connection structure. The dynamic control enables consistency without requiring complex static configuration.
Solution Approach 2:
The patent changes the operating parameters (charging/discharging rates) dynamically for each battery cluster through DC/DC converters. By adjusting these parameters based on real-time battery states, the system achieves consistent charging and discharging across clusters with different characteristics, while maintaining a simple parallel connection architecture.
3Quantity of substance
If one DC/AC inverter is shared by multiple battery clusters, then cost is reduced, but control flexibility and utilization rate are limited
Solution Approach 1:
The patent segments the power conversion function by placing DC/DC converters at each battery cluster level while sharing a common DC/AC inverter. This hierarchical segmentation provides control flexibility at the cluster level for consistent charging/discharging, while maintaining cost efficiency through shared grid interface equipment. The segmentation enables adaptability without proportionally increasing overall system cost.
Solution Approach 2:
The patent introduces dynamic control capability at the DC/DC converter level for each battery cluster, enabling flexible adjustment of charging and discharging rates. This dynamic control provides the necessary adaptability and control flexibility, while the shared DC/AC inverter maintains cost efficiency. The dynamic control layer enables versatility without requiring dedicated inverters for each cluster.
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 approach improves the utilization rate of energy storage modules, reduces waste, and lowers costs by maintaining consistent module performance and simplifying system management, while adapting to various application scenarios.
Implementation Method 1
One energy storage module in the energy storage unit cluster includes one energy storage element group and one DC/DC converter, and the energy storage element group is coupled to the second bus by using the DC/DC converter
Data Source
AI summary
An energy storage system includes one or more energy storage unit clusters, and the energy storage unit cluster includes at least two energy storage modules connected in series. The energy storage system further includes a first bus, a second bus, and a centralized monitoring system of the energy storage unit cluster, where the second bus is a direct current bus. The energy storage unit cluster is coupled to the first bus by using a first converter. One energy storage module includes one energy storage element group and one DC/DC converter, and the energy storage element group is coupled to the second bus by using the DC/DC converter. The centralized monitoring system is connected to the energy storage unit cluster through a control bus, and is configured to control a DC/DC converter in any energy storage module in the energy storage unit cluster.