Charge Equalization Circuit for Series Battery Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing charge equalization methods for series-connected lithium-ion battery cells are inefficient due to energy losses and the need for multiple cycles to balance cell voltages, which reduces the overall energy capacity and shortens the operational time of battery-powered devices.
Innovation Solution
A circuit with a storage device, such as an inductor, and semiconductor switches that allow for direct energy transfer between battery cells, enabling efficient charge equalization by intermediately storing energy in the magnetic field and selectively connecting cells for charging or discharging, thereby balancing the entire stack quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing charge equalization methods are used, then battery cells can be balanced, but energy losses occur and multiple cycles are required
Solution Approach 1:
The patent introduces a storage device as an intermediary energy buffer between battery cells. Energy is first stored in the storage device from a first battery cell, then transferred to a second battery cell. This indirect transfer path reduces energy losses compared to direct cell-to-cell equalization methods, while enabling complete energy utilization without requiring multiple balancing cycles.
2Stability of the object's composition
If existing charge equalization methods are used, then cell voltages can be balanced, but operational time of battery-powered devices is shortened
Solution Approach 1:
The patent changes the operational parameters by utilizing the complete energy capacity of battery cells through controlled charging and discharging cycles via the storage device. By fully charging each cell to its maximum capacity and then fully discharging when needed, the system extends operational time while maintaining cell voltage balance, rather than conservatively limiting capacity to prevent imbalance.
3Reliability
If multiple cycles are used for charge equalization, then complete balancing is achieved, but charge equalization time increases
Solution Approach 1:
The patent implements continuous useful action by establishing a seamless energy transfer pathway through the storage device. Energy flows continuously from charged cells to discharged cells without interruption or requirement for multiple discrete balancing cycles. This continuous operation achieves complete charge equalization in a single operational phase, reducing time while maintaining reliability through the buffered energy transfer mechanism.
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 allows for each battery cell to be fully charged to its maximum capacity, increasing the range of electric vehicles and reducing costs by using fewer standard components, while minimizing energy dissipation and shortening the charge equalization time.
Implementation Method 1
enabling efficient charge equalization by intermediately storing energy in the magnetic field
Data Source
AI summary
In one embodiment, a circuit comprising a first set of one or more semiconductor switches coupled to a first node and a first terminal of an energy store configured to store energy, and a second set of one or more semiconductor switches coupled to a second node and a second terminal of the energy store, each of the first and second sets of semiconductor switches being configured to couple to a terminal of a battery cell.