Cell-Level Battery Protective Device for Short-Circuit Isolation
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Solution Overview
Problem
Existing battery systems, particularly high-voltage batteries in motor vehicles, face challenges in quickly and reliably detecting and responding to electrical short-circuits, which can lead to safety issues and potential damage.
Innovation Solution
A protective device is integrated into each battery cell, featuring a microcontroller or analog circuit with sensors to detect voltage drops and isolate the energy storage unit from cell terminals upon detecting a short-circuit, allowing for rapid and precise identification and isolation of short-circuits, even at the individual cell level, using electronically controllable switches for quick power disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If main contactors are used to switch off the high-voltage battery in the event of a short-circuit, then the battery can be disconnected from the electrical system, but the response time is too slow due to the mechanical switching mechanism
Solution Approach 1:
The battery system is divided into individual battery cells, each equipped with its own protective device and electronically controllable switch. This segmentation allows independent monitoring and isolation of each cell, enabling faster response times compared to switching off the entire battery system through main contactors.
Solution Approach 2:
The patent replaces the mechanical main contactor switching mechanism with electronically controllable switches (such as transistors or other semiconductor devices) at the battery cell level. This substitution eliminates the inherent delay of mechanical contactors and enables much faster isolation of short-circuits through electronic control.
2Reliability
If the entire high-voltage battery is switched off upon detection of a short-circuit, then safety is improved, but the response cannot be localized to the affected cell level
Solution Approach 1:
Each battery cell is equipped with an independent protective device that monitors its own cell voltage and can independently isolate it from the electrical system. This segmentation enables precise localization of short-circuits to the affected cell while leaving other healthy cells operational.
Solution Approach 2:
The protective device continuously monitors the cell voltage of each individual battery cell and uses this feedback to detect short-circuits. When a short-circuit is detected in a specific cell, only that cell is isolated, providing localized response rather than system-wide shutdown.
3Measurement precision
If individual battery cells are monitored with separate protective devices, then short-circuit detection precision is improved, but the device complexity increases
Solution Approach 1:
Each battery cell is equipped with a protective device that autonomously monitors its own cell voltage and performs self-isolation in the event of a short-circuit. This self-service approach eliminates the need for complex centralized monitoring systems and reduces overall system complexity while maintaining high detection precision.
Solution Approach 2:
The protective device is designed as a universal module that can be applied to each battery cell with the same basic functionality. This standardized multi-functional design simplifies the overall system architecture compared to custom-designed monitoring systems for each cell.
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 enables faster and more reliable detection and isolation of short-circuits, enhancing safety by preventing damage and ensuring quicker power disconnection than previous designs, while also allowing for differentiation between internal and external short-circuits and adapting to cell parameters for improved reliability.
Implementation Method 1
detecting a voltage dropping via the energy storage unit
Data Source
AI summary
A protective device for switching off a battery cell of a motor vehicle battery in the event of an electrical short-circuit. The battery cell has two cell terminals and an energy storage unit for storing energy. The energy storage unit is connected to the cell terminals in an electrically conductive manner in order to provide cell voltage to the cell terminals. The protective device detects the short-circuit as a function of at least the cell voltage affecting the battery cell. In this case, the battery cell has the protective device and at least one switching device, which is arranged between the energy storage unit and at least one of the cell terminals. The protective device isolates the energy storage unit from the at least one of the cell terminals in order to switch off the battery cell by the switching device.