Battery Management Systems for Electric Vehicles

Efficient thermal management system for warming batteries and cab of electric vehicles. It uses a primary circuit with a tank, pump, and bypass to circulate battery cooling fluid. A secondary circuit has an electric heater, heat exchangers, and valves. The secondary circuit heats a thermal fluid using the electric heater. This heated fluid then transfers heat to the battery fluid via an exchanger in the tank. Any remaining heat is transferred to the cab fluid via another exchanger before returning to the electric heater. This allows efficient warming of battery fluid using the electric heater instead of a separate battery heater, while also warming cab fluid.

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Determining short circuit risk in battery cells after manufacturing to reduce fire hazards. The technique involves monitoring self-discharge current and voltage during cell standby periods to calculate a total resistance. If the calculated resistance is below a threshold, it indicates accelerated short circuit degradation and raises a short circuit risk alert.

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Compact power electronics device for controlling batteries in electric vehicles that reduces size and cost compared to using standard DCDC converters. The device is a printed circuit board (PCB) with integrated power electronics to control battery cells. The DCDC converter on the PCB has a compact planar layout formed directly on the substrate. Features like a closed loop primary winding, integrated leakage inductance, planar integrated transformer, modular secondary winding, and rectifier variants allow high power output with fewer components. The planar geometry enables a thickness less than 1mm.

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Control method for charging facilities to enable stable charging of batteries even when the charging facility output voltage is lower than a minimum limit. The method involves transmitting an outputtable current value from the charging facility to the vehicle. The vehicle sets a charging current command based on this value. The charging facility then uses the command to supply charging power to the battery. The outputtable current is set to decrease as the battery voltage drops. This widens the charging range and allows stable charging of low-voltage batteries, even if the facility output voltage is below the minimum limit.

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A system to optimize electric vehicle (EV) charging by dynamically allocating charging stations based on vehicle battery size and charge rate. The system involves communication between EVs and charging stations using wireless signals. The EVs transmit their battery level, draw rate, destination, and charge capacity. The stations stack this data against their current status to determine optimal charging assignments. This allows faster, more efficient, and fairer utilization of charging infrastructure by matching EV needs to station capabilities.

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Early detection of thermal runaway events in batteries, like those used in electric vehicles, by detecting the initial venting of gases during the runaway process. A sensor measures the thermal conductivity of the gas atmosphere inside the battery. Changes in conductivity due to venting can be detected as an indicator of an impending thermal runaway. An apparatus with interface and processing circuitry receives the conductivity measurement and determines if venting has occurred. This allows early warning of potential thermal runaway events to mitigate safety risks.

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Battery control system that improves battery charging and discharging reliability and efficiency by accurately determining charging and discharging limits based on real-time battery conditions. The system predicts internal resistance based on projected operating conditions, but switches to using real-time measured internal resistance if the battery voltage is above a threshold. This prevents overcharging and undercharging by better matching the actual battery resistance.

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Reflector units for bi-directional vehicles that can change color to indicate front or rear depending on the vehicle's orientation. The reflector units have elements with two sides, one that reflects a first color and one that reflects a different color. An actuator rotates the elements to expose the appropriate side based on vehicle orientation. This allows bi-directional vehicles to comply with regulatory requirements for front/rear reflectors.

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Detecting the cause of discharging a vehicle battery by waking up a control module when a vehicle controller draws more current. The waking module identifies the first controller that powered on, then determines if other controllers should be sleeping but aren't. This allows finding devices that keep the battery drained when supposed to be off.

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Intelligent battery charge depletion system for range-extended electric vehicles (REEVs) that optimizes battery charging strategy based on estimated vehicle load. The system monitors battery state of charge, road load, and gross vehicle weight. It determines a modified charge depletion setpoint that increases as load increases, maintaining a torque reserve. This prevents premature depletion when load is low. The engine recharges the battery. It's more efficient than fixed charge depletion or sustained charging.

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Efficient thermal management system for warming electric vehicle batteries and cabins in cold weather without excessive viscous fluid issues. It uses a dual pump setup with a clutch to transfer power between pumps. One pump circulates battery fluid through the battery pack to warm it. The other pump circulates a separate fluid through a heat exchanger in the battery tank. In cold conditions, a magnetic clutch connects the pumps so the main pump's rotation drives both pumps. This allows efficient warming of the battery fluid using the main pump's power. In warmer conditions, the clutch disengages and the secondary pump warms the cabin fluid instead. This prevents high viscosity battery fluid issues by using the main pump for critical battery heating only when needed.

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Monitoring swelling of battery containers without internal sensors by attaching an external strain gauge to a tightening strap around the battery. The strap has a tightening mechanism to pull it taut against the battery container when swelling occurs. The strain gauge stretches with the container expansion and is connected to an electronics package that reads the gauge and transmits the strain data to a battery management system.

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Thermal runaway detection and control for lithium-ion batteries to prevent battery fires and explosions. The method involves mounting palladium-based nano sensors on individual battery cells to detect hydrogen concentrations. If hydrogen levels exceed a threshold, charging/discharging is stopped. If hydrogen stays below another threshold, charging/discharging resumes. This allows selective cell shutdown and restart based on hydrogen levels, preventing thermal runaway spread.

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Isolation resistance monitoring for battery management systems (BMS) in electric vehicles (EVs) that enables accurate and cost-effective isolation resistance measurement for both the high-voltage (HV) battery pack and the floating high-voltage link side when disconnected. The monitoring uses a single device and power supply powered from the 12V auxiliary voltage of the EV. The device applies a test voltage from the auxiliary supply to a resistor, measures the resulting current, and calculates the isolation resistance. This allows isolation resistance monitoring for both the HV pack and link sides using just one device and power source, simplifying and reducing cost compared to separate monitoring for each side.

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Reliable diagnosis of low battery voltage in electric vehicles to prevent cell swelling and fires. The method involves differentiating between low voltage and disconnection diagnosis. It uses a higher threshold voltage and longer time duration for low voltage diagnosis versus disconnection diagnosis. This prevents misdiagnosis when cells rapidly drop voltage due to degradation vs. disconnection. The battery diagnosis system also performs low voltage diagnosis regardless of disconnection diagnosis results if cell voltage meets the entry condition. This improves reliability compared to traditional methods that only diagnose low voltage when cell voltage stays below 1.5V for 5 seconds.

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Test fixture for battery cell chemistry evaluation that enables more comprehensive monitoring and sampling of battery performance parameters beyond voltage. The fixture has a housing with separate battery cell and sensor chambers, connectors for gas sampling, pressure sensing, and valve actuation. A biasing member urges the cell into contact with the cell chamber. Gas, pressure, and valve connectors are fluidically connected to the cell chamber. This allows sampling, sensing, and controlling cell gases, pressures, and valves during cycling.

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Early warning system to detect thermal runaway in electric vehicle batteries using acoustic sensors. The system monitors sound waves emitted from battery cells to predict thermal runaway before it escalates. Acoustic sensors detect low frequency infrasound generated by gas bubbles forming during early stages of thermal runaway. An algorithm analyzes the acoustic data to predict thermal runaway. This allows earlier intervention to prevent escalation compared to temperature sensors.

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Compensating open circuit voltage (OCV) of a battery to improve accuracy of battery state estimation algorithms, especially for aging batteries. The compensation is based on monitoring the voltage peaks in the cell's voltage range over cycling. By tracking the peak voltage and its SOC each cycle, and the peak voltage variation, the compensation factors are determined. This allows precisely adjusting the OCV for a given SOC based on the aging characteristics of the specific cell.

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Determining the health of a battery used in a hybrid vehicle by calculating its charge capacity. The method involves depleting the battery to a target low state, resting it, measuring the resting voltage, charging to a target high state, resting again, measuring the high state voltage, and calculating capacity from the low and high resting voltages. Accumulated charge during charging can also be used. This provides an accurate capacity measurement without relying on state of charge during operation.

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Battery diagnosis system for electric vehicles that can accurately diagnose voltage deviations in batteries, even when voltage suddenly drops due to severe cell degradation. The diagnosis is performed differently depending on whether the cell voltage is normal or abnormal. If abnormal, output power is limited. This prevents continued use of degraded batteries that could lead to fires. If normal, output power is limited more to mitigate potential issues. The differentiated diagnosis and response allows more effective battery management and safety for electric vehicles.

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