Battery Cell Stack Overcharge Bypass Circuit
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Solution Overview
Problem
Existing battery pack systems face the risk of overcharge leading to potential explosion, as current solutions like electrical separation from the high current path can cause sudden vehicle stoppage and imbalance in voltage between cell stacks, which may result in damage or unsafe conditions.
Innovation Solution
An apparatus that bypasses the overcharged cell stack, allowing charge current to be supplied to remaining stacks while adjusting resistance values in bypass paths to prevent overcurrent, ensuring continuous charging and safe operation of non-overcharged cell stacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is electrically separated from the high current path when overcharged, then overcharge is prevented, but the electric vehicle may suddenly stop and operation continuity is compromised
Solution Approach 1:
The patent introduces a bypass circuit as an intermediary path that allows charge current to flow around the overcharged cell stack. This mediator enables the system to prevent overcharge in the affected stack while maintaining continuous charging operation for the entire battery pack, avoiding sudden vehicle stoppage.
Solution Approach 2:
The patent segments the battery pack into individual cell stacks with independent monitoring and control. When one stack becomes overcharged, only that specific stack is diverted through the bypass circuit while other stacks continue normal charging. This segmentation allows selective protection without compromising the entire system's operation continuity.
2Reliability
If charge current is diverted from an overcharged cell stack, then overcharge is prevented, but voltage imbalance between cell stacks increases
Solution Approach 1:
The patent incorporates a control unit that continuously monitors the voltage of each cell stack and dynamically adjusts the bypass circuit operation. When voltage imbalance is detected, the control unit regulates the bypass current to prevent excessive voltage differences between stacks, maintaining overall voltage balance while still preventing overcharge.
Solution Approach 2:
The bypass circuit resistance is made dynamically adjustable rather than fixed. The control unit modifies the bypass path resistance in real-time based on the charging state and voltage differences between stacks, enabling adaptive current distribution that prevents both overcharge and excessive voltage imbalance.
3Ease of operation
If bypass paths are provided for overcharged cell stacks, then charging continuity is maintained, but device complexity increases
Solution Approach 1:
The bypass circuit is designed with multi-functionality to reduce overall system complexity. The same bypass path structure serves multiple purposes: it provides alternative current routing for overcharged stacks, enables voltage balancing through controlled current diversion, and can be integrated with existing battery management system components. This universal design approach minimizes the number of additional components needed.
4Reliability
If resistance values in bypass paths are adjusted to prevent overcurrent, then safety is improved, but control complexity increases
Solution Approach 1:
The patent pre-configures the bypass circuit with predetermined resistance values and control logic that are established before operation. The control unit contains pre-programmed thresholds and response protocols for detecting overcharge conditions and adjusting bypass resistance accordingly. This preliminary preparation simplifies real-time control by relying on pre-established parameters rather than complex real-time calculations.
Data Source
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AI summary
Provided is an apparatus and method for protecting each of a plurality of cell stacks included in a battery pack from overcharge. The overcharge prevention apparatus according to an aspect of the present disclosure is for preventing the overcharge of a plurality of cell stacks connected in series within a high current path. The overcharge prevention apparatus includes a voltage measuring unit configured to measure voltage of each cell stack, and generate a first monitoring signal indicating the measured voltage, a current regulating unit configured to selectively provide a bypass path to each cell stack, and a controller connected to the voltage measuring unit and the current regulating unit allowing communication. The controller is configured to control the current regulating unit based on the first monitoring signal from the voltage measuring unit.