Voltage and Current Monitoring Systems for EV Batteries

Detecting thermal events in parallel-connected battery cells of an electric vehicle battery pack using voltage rebound monitoring. The technique involves confirming a voltage rebound in a group of parallel-connected cells as a faster and more effective way to detect thermal events compared to just monitoring voltage drop below a threshold. The voltage rebound is a characteristic voltage behavior during thermal propagation in parallel cells where the voltage rebounds slightly after an initial drop. Detecting this rebound along with other conditions like high temperature or pressure confirms a thermal event.

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Predicting and preventing thermal runaway in battery packs used in vehicles to prevent cascading cell failures. The method involves monitoring cell parameters like voltage, current, and temperature during charging to determine the charging response. This response is then analyzed to estimate the likelihood of thermal runaway. The vehicle operation can then be controlled to prevent runaway based on this predicted risk.

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Battery monitoring system for electric vehicles that detects potential cell imbalances and thermal runaway risks by ranking cell voltages and analyzing the ranking differences over time. The system uses a sensor to get cell voltages, sorts them into a ranking, repeats the ranking at regular intervals, and compares the changes. If a cell's ranking consistently lags behind, it indicates potential imbalance. If adjacent cells' rankings increase while the lagging cell's stays low, it indicates thermal runaway risk. The system uses this analysis to control battery operation and predict thermal runaway.

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Early warning system to detect thermal runaway risk in electric vehicles before it becomes critical. The system monitors cell voltages over time to identify voltage characteristics indicative of thermal runaway. It divides the cell voltage data into time windows based on collection timing, extracts voltage characteristics from each window, and checks if they meet thresholds to determine if the vehicle has a runaway risk. If so, it alerts the user to replace the battery before runaway occurs.

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Detecting and mitigating thermal runaway in vehicle battery packs to prevent cell fires. The method involves monitoring cell voltage and temperature in a vehicle battery pack. If a cell short occurs, it analyzes the voltage signal using techniques like wavelet transforms and power spectra to detect rapid voltage modulations and energy releases indicating thermal runaway. If runaway is confirmed, it initiates actions like stopping charging, releasing pressure, cooling, warning, and contacting emergency services.

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Monitoring system for detecting thermal runaway in rechargeable battery packs using sensors on the heat transfer plates between cells. The sensors monitor parameters like wave attenuation, temperature, or impedance to detect if the plate temperature exceeds a threshold indicative of a runaway event. This allows earlier detection and mitigation of thermal runaway compared to just monitoring the cells themselves. The sensors can be ultrasonic, temperature, or thin wire circuits.

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Detecting thermal runaway of battery cells in electric vehicles to quickly alert occupants of potential fire hazards. The system uses multiple sensing lines to monitor battery voltages. Main lines connect to individual cells to measure their voltages. Auxiliary lines connect to input and output terminals of the battery module. By comparing the sum of cell voltages to the module voltage, abnormalities in cells or main lines can be detected. If the cell sum and module voltages match, all is normal. If they differ, further checks are made. If module voltage is normal, the main lines are faulty. If module voltage is abnormal, the cells have runaway. This rapid detection allows warning occupants before serious damage occurs.

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Battery connector with integrated thermal cutoff to detect overtemperature and overcurrent conditions in battery packs and cells. The connector has a thermal switching device, like a temperature-sensitive resistor, mounted on the connector body and thermally coupled to the battery terminal. If the battery temperature exceeds a threshold, the switching device alters the signal conveyed by the connector to indicate overtemperature. This allows a battery management system to detect and respond to overheating without additional sensors.

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Detecting and mitigating thermal runaway in vehicle battery pack cells. The method involves monitoring cell voltages at a specific rate, identifying voltage decreases and modulations coincident with temperature increases indicating cell shorts, and signaling if a cell reaches 70°C and then rapidly rises to 500°C in 5 seconds. This indicates thermal runaway. The voltage analysis involves derivative calculation, FFT power spectrum estimation, and wavelet decomposition.

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Electrified vehicle battery pack with integrated temperature-regulated current shunts for measuring cell currents. The pack uses the liquid cooling system to regulate the shunt temperature. This prevents shunt errors due to temperature variation. The shunts are mounted directly on the pack's heat exchanger plate or cell end plates. The cooling system dissipates heat from the shunts. This allows accurate current sensing without the need for external shunts. The shunt temperature is monitored and controlled to ensure accurate current measurements.

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Storage battery device with improved safety and convenience by using a line heat detector (LHD) to detect issues like overcharging and ground faults in battery packs. The LHD is a continuous line that makes thermal contact with the bottom surfaces of the battery packs. It allows detecting heat generation due to factors like incomplete dielectric breakdown and ground faults, even when BMS and CMU fail. The LHD laid near the pack bottoms can detect heat from overcharging and ground fault currents. This improves safety by allowing advanced prevention of hazards like thermal runaway and fires.

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Monitoring systems and methods to detect faults in energy storage systems like batteries used in electric vehicles. The monitoring uses sensors and parameter estimations to detect unexpected behavior indicative of faults like loose connections, failed cells, or thermal issues. The monitoring compares sensed temperatures, electrical characteristics, and thermal calculations to expected values to identify deviations that may indicate faults.

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Detecting and warning of battery thermal runaway in electric vehicles to mitigate fires and hazards. The method involves monitoring voltages of individual battery cells using main sensing lines, and also monitoring the overall battery module voltage using auxiliary lines. By comparing the cell and module voltages, it can determine if there's a cell fault or main sensing line fault. This allows differentiating between cell and line issues during thermal runaway.

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Controlling thermal runaway propagation in battery packs with multiple modules by selectively discharging modules to prevent runaway spread. When a thermal runaway is detected in one module, the controller checks if current is flowing through that module. If not, it decouples the module to isolate the runaway. If current is flowing, it connects the other modules to an external load to discharge them, preventing runaway propagation. This controlled discharge can mitigate thermal runaway chain reactions in battery packs.

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Detecting and mitigating thermal events in battery packs of electrified vehicles. The battery pack has a controller that monitors parameters like cell temperatures, voltages, and currents. If a thermal event is detected based on the monitored data, the controller issues corrective actions like venting, slowing the vehicle, shutting down, providing prompts, etc. This rapid response helps prevent escalation and damage from thermal events in battery packs.

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Monitoring and balancing battery cells with voltage levels above the measurement range of the battery management system. It uses switch circuitry to selectively connect a monitoring circuit to distribute energy from the high voltage cell to a node. The voltage measurement circuit then compares voltages between the node and cell terminals to determine the actual cell voltage, even if it's above the direct measurement range. This allows monitoring and balancing cells with very high voltages that exceed the controller's range. The switching circuitry also balances cells by connecting them together when needed.

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Battery management system for high voltage battery packs that enables accurate and early detection and characterization of fault conditions, such as isolation faults and Y capacitance issues, to improve safety and reliability. The system uses switchable resistances connected between the battery stack and ground to measure currents and determine fault location. It also monitors Y capacitance by settling current sampling after switch closure. This allows identifying isolation faults within cells and quantifying Y capacitance changes.

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Electrified vehicle battery pack with integrated temperature regulated current shunts and liquid cooling to improve accuracy and reliability of battery monitoring. The battery pack uses temperature regulated current shunts to measure current flow into and out of the battery cells. These shunts are cooled using the pack's liquid cooling system to maintain accurate current measurements by preventing overheating. The cooled shunts are mounted on the heat exchanger plate or battery array. The cooling system dissipates heat from the shunts into the plate or end plate, which then transfers it to the main cooling circuit. This regulates the shunt temperature for accurate current sensing.

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Battery safety evaluation method that nondestructively estimates the thermal runaway temperature of a degraded battery cell in order to prevent spreading fires in multi-cell packs. The method involves estimating the internal state parameters of the battery during charge/discharge cycles using voltage and current data. It then estimates the heat generation of the battery during temperature changes using reference data. Finally, it calculates a safety index representing the temperature of the battery during temperature changes based on the estimated heat generation.

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Early detection of thermal runaway events in battery packs to mitigate damage and risks by monitoring the electrical isolation resistance. The system continuously monitors the isolation resistance of the battery pack. If it falls below a threshold, indicating cell failure, and certain conditions are met like rapid falloff rate, short recovery time, or secondary effects like voltage loss, humidity rise, temperature spike, or coolant overheat, it triggers a response like warnings, load reduction, cooling, or fire suppression.

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