Battery Pack Current Control Circuits for Disparate Cell Impedance
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Solution Overview
Problem
Designing a battery pack for portable electronic devices that incorporates disparate battery cell types poses challenges due to impedance mismatches, leading to inefficient charge times and reduced battery performance, as existing solutions struggle to balance charge currents across cells of different impedances and chemistries.
Innovation Solution
Implementing a battery pack configuration with current control circuits, such as resistive elements, DC/DC regulators, or active current limiting devices, to manage charge currents and balance impedance across cells of different types, ensuring each cell type operates within its charge current limit, thereby optimizing charge rates and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If battery cells of disparate types with different impedances are used in a battery pack, then the battery pack can meet space constraints and performance requirements under particular environmental conditions, but impedance mismatches lead to inefficient charge times and charge current imbalance
Solution Approach 1:
The patent applies local quality by introducing individual current control circuits for each battery cell or cell group. These circuits provide localized impedance adjustment or current limiting specifically for cells with lower impedance, allowing each cell to be managed according to its specific characteristics rather than treating all cells uniformly. This resolves the charge current imbalance problem while maintaining the ability to use disparate cell types.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the impedance or current limits of individual battery cells through control circuits. By changing the electrical parameters (current, voltage, or impedance) of specific cells based on their characteristics and state of charge, the system optimizes charge distribution across disparate cell types, preventing overcharge of low-impedance cells while ensuring efficient charging overall.
2Adaptability or versatility
If battery cells of disparate types are used in a battery pack, then space constraints and environmental performance requirements can be satisfied, but voltage imbalances and reduced battery performance occur
Solution Approach 1:
The patent implements feedback mechanisms through control circuits that continuously monitor the state of charge, voltage, and current of each battery cell. This feedback allows the system to detect imbalances and adjust charging parameters in real-time, preventing voltage imbalances and ensuring reliable performance across disparate cell types. The feedback loop enables dynamic compensation for cell variations.
Solution Approach 2:
By applying local quality through individual cell monitoring and control, the patent ensures that each cell is managed according to its specific characteristics. This localized approach prevents voltage imbalances by addressing the needs of each cell type individually, thereby maintaining overall battery pack reliability and performance stability despite using disparate cell types.
3Productivity
If higher charge currents are applied to battery cells, then faster charging rates are achieved, but over-charge conditions and battery damage may occur
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting charge current levels based on real-time cell state monitoring. The control circuits modify charging parameters (current, voltage, or impedance) according to each cell's characteristics and state of charge, enabling fast charging when safe and reducing current when cells approach their limits. This prevents over-charge damage while maximizing charging rate.
Solution Approach 2:
The feedback mechanism continuously monitors cell voltage, current, and state of charge, allowing the system to detect when cells are approaching their charge limits. Based on this feedback, the control circuits automatically adjust or terminate charging for individual cells, preventing over-charge conditions while maintaining high overall charging efficiency through intelligent current management.
Data Source
AI summary
Methods and apparatus for controlling charge current in a battery pack containing cells of disparate types are disclosed. The methods include receiving a charge current for charging a battery pack that includes one or more battery cells of a first cell type, and one or more battery cells of a second cell type. Each battery cell of the first cell type has a first impedance and a first charge current limit. Each battery cell of the second cell type has a second impedance greater than the first impedance and a second charge current limit greater than the first charge current limit. The methods include reducing, by a respective current control circuit associated with each battery cell of the first cell type, the amount of the received charge current through the battery cell of the first cell type to an amount less than the first charge current limit.