Shared-Inductor Cell Balancing Circuit for Lower BMS Cost
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Solution Overview
Problem
The high cost of active cell balancing circuits in battery management systems due to the large number of elements required for effective voltage balancing, which limits the balancing current and increases costs.
Innovation Solution
A reduced-element cell balancing circuit design using transistors and inductors to transfer energy between battery cells, minimizing the number of components while maintaining effective voltage balancing by controlling the switching of transistors to manage current paths through inductors and diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active cell balancing circuit is used to transfer energy between battery cells, then voltage balancing effectiveness is improved, but the number of elements increases and cost increases
Solution Approach 1:
The patent combines multiple balancing circuits into a shared architecture where inductors and control units are共用 among multiple battery cell groups. This merging approach maintains the active energy transfer capability for effective voltage balancing while reducing the total number of elements by eliminating redundant components across different cell groups
Solution Approach 2:
The inductors and control units are designed to serve multiple functions and multiple battery cell groups simultaneously. A single inductor can facilitate energy transfer between different cell groups, and control units manage multiple balancing operations, thereby reducing overall device complexity while maintaining balancing effectiveness
2Use of energy by moving object
If many elements are used in the active cell balancing circuit, then energy transfer capability is improved, but the cost of the cell balancing circuit increases
Solution Approach 1:
The patent merges energy transfer pathways by using shared inductors that can transfer energy between multiple battery cell groups. This approach maintains robust energy transfer capability while reducing the total component count and associated costs by eliminating the need for separate inductors for each cell group
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 design reduces the overall cost of the cell balancing circuit while maintaining effective voltage balancing by efficiently transferring energy between battery cells, reducing the number of elements needed compared to conventional active balancing circuits.
Implementation Method 1
a first inductor L1 having a first terminal connected to a first battery cell C1 and a second terminal connected to a second battery cell C2
Data Source
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AI summary
A cell balancing apparatus of a battery module in which a first battery cell, a plurality of second battery cells, and a third battery cell are connected in series is provided. A first terminal of a first inductor is connected to a negative electrode of the first battery cell, and a first terminal of a second inductor is connected to a positive electrode of the third battery cell. A first transistor is connected between a second terminal of the first inductor and a second terminal of the second inductor. A first active element is connected between a positive electrode of the first battery cell and the second terminal of the first inductor, and a second active element is connected between a negative electrode of the third battery cell and the second terminal of the second inductor.