Battery String Balancing via Common Charge-Discharge Node
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Solution Overview
Problem
Existing battery balancing methods, such as passive and active balancing, are inefficient and complex, and require auxiliary power storage devices, adding weight and complexity to battery management systems.
Innovation Solution
A battery management system that uses a common charge/discharge node connected to each intermediate node of a battery string, allowing for rapid balancing without auxiliary power storage, using a minimum number of sensors and switches, and employing a buck-boost chopper for charging and discharging subsets of the battery string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive or active balancing methods are used, then battery cells can be balanced, but auxiliary power storage devices are required, adding weight and complexity to the battery management system
Solution Approach 1:
The patent extracts and eliminates the auxiliary power storage devices from the balancing system. Instead of using separate batteries or capacitors to transfer charge between cells, the system directly connects cell groups through switching circuitry, removing the disturbing component (auxiliary storage) while maintaining the balancing function.
Solution Approach 2:
The switching circuitry serves multiple functions: it connects cell groups for balancing, disconnects them for charging/discharging, and reconfigures the circuit topology dynamically. This multi-functional approach replaces the need for dedicated auxiliary power storage components.
2Reliability
If passive or active balancing methods are used, then battery cells can be balanced, but the system requires additional components, increasing weight
Solution Approach 1:
The patent removes auxiliary power storage devices (additional batteries, capacitors) from the system architecture. By using the existing battery cells themselves as both the source and destination for charge transfer through direct switching connections, the system eliminates the extra weight of auxiliary storage components.
Solution Approach 2:
The patent merges the balancing function with the existing battery string structure. Instead of adding separate balancing components, the system uses the battery cells themselves and reconfigures their connections through switching circuitry, combining the balancing operation with the existing energy storage structure.
3Productivity
If traditional balancing methods are used, then cell capacity utilization can be improved, but the balancing process is slow and inefficient
Solution Approach 1:
The patent employs dynamic reconfiguration of the battery string topology through switching circuitry. The system can dynamically connect and disconnect different cell group configurations, enabling rapid charge transfer between cells with varying states of charge, thereby significantly accelerating the balancing process compared to static passive methods.
Solution Approach 2:
The system performs periodic state-of-charge measurements and reconfigures connections between cell groups in cycles. This periodic action allows the system to identify imbalances and execute corrective charge transfers efficiently, improving both balancing speed and energy utilization.
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
Enables high-power, cost-effective, and lightweight battery balancing with reduced complexity by minimizing the need for additional components, achieving uniform charging across battery cells.
Implementation Method 1
Battery cells are often arranged in a series connection to establish a desired voltage and current capability
Implementation Method 2
a power sink connected via a discharge switch to the CCD node, the power sink configured to dissipate power discharged from a particular intermediate node or the battery string
Data Source
AI summary
This disclosure describes a battery management system that can balance a string of battery cells rapidly, at high power, and without the use of a large auxiliary battery or excessive switches/transistors. A single switched tap is provided at each intermediate node of the battery string, allowing charging and discharging of subsets of the battery string (e.g., cell 1, cells 1 and 2, cells 1-3, etc.). A common charge/discharge (CCD) node can be connected to any one of the intermediate nodes, resulting in a parallel connection with the battery string for each cell at or below the connected intermediate node in the string. A sink is provided which can be used to discharge groups of cells using the connected intermediate node. Additionally, a source can be provided, such as a buck-boost chopper acting as a current supply, to charge the group of cells using the connected intermediate node.