Battery Charge Equalization Circuit Using Energy Buffer
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Solution Overview
Problem
Battery systems with cells connected in series or parallel exhibit varying charging and discharging behaviors due to different internal parameters, necessitating a method for charge equalization that accounts for these differences to ensure efficient and balanced energy distribution.
Innovation Solution
A charge equalization method and circuit that utilizes an energy buffer and switchable connections to transfer energy between cells, allowing the charging voltage to exceed individual cell open-circuit voltages, thereby equalizing the state of charge across cells, potentially connecting cells in series or parallel to optimize energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cells are connected in series or parallel in a battery system, then the battery system can provide higher voltage or capacity, but the different internal parameters of cells cause varying charging and discharging behaviors that make charge equalization difficult
Solution Approach 1:
The battery system is divided into multiple cell groups (first cell group and second cell group) that can be independently managed. The charge equalization circuit operates on specific groups rather than the entire battery system at once, allowing targeted charge redistribution while maintaining overall system power output.
Solution Approach 2:
A charge equalization circuit is introduced as an intermediary component between cell groups to transfer charge. This circuit includes switching elements and energy storage components that mediate the charge transfer process, enabling equalization without directly connecting cells and preventing interference with normal battery operation.
2Reliability
If conventional charge equalization methods are used, then some charge transfer is achieved, but the process is slow and inefficient due to direct cell connections
Solution Approach 1:
The charge equalization process uses periodic switching of the charge equalization circuit between different operational states. The switching elements alternately connect and disconnect energy storage components to create oscillating charge transfer, which accelerates the equalization process compared to continuous direct connection methods.
Solution Approach 2:
The charge equalization circuit dynamically changes electrical parameters such as resistance, capacitance, and inductance by switching between different circuit configurations. These parameter changes optimize the charge transfer rate at different stages of the equalization process, improving both speed and efficiency.
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 enhances the efficiency and speed of charge equalization, preventing overcharging and extending battery discharge time by ensuring all cells reach chemical energy storage levels uniformly, thus improving the overall battery system performance.
Implementation Method 1
a charge equalization circuit (260) which can be brought into a first state and a second state, and an energy buffer store (280)
Data Source
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Figure 2
AI summary
The invention relates to a method for charge equalization between two cells of a cell network of a battery system, and to a battery system having a charge equalization circuit and comprising two or more cells having a resting voltage. The charge equalization circuit feeds an intermediate energy store in a first state. In a second state of the charge equalization circuit, a cell is charged at a charging voltage, wherein the charging voltage is greater than any of the two cell resting voltages.