Tesla's Innovations in Battery Management Systems

An operational mode for electric vehicles that extends the life of the vehicle's battery pack. The mode involves adjusting charging, discharging, and temperature limits when the vehicle is parked for extended periods. When selected, the mode allows the battery to self-discharge deeper before charging, limits charging rates, and maintains a higher minimum charge level. This reduces cycling and stress on the battery when left connected to a charger. The mode also sets temperature limits and balancing during discharge.

Source

Battery pack charging method and management system that improves cycle lifetimes for automotive lithium-ion batteries by adapting to capacity degradation with age. It involves charging to specific state-of-charge (SOC) windows based on the expected driving range needs. By charging to smaller SOC ranges as the pack ages to compensate for capacity loss, it extends overall pack life. The system determines the optimal SOC range based on past usage and user input.

Source

Improving cycle life of lithium-ion battery packs in electric vehicles by dynamically adjusting charge profiles based on anticipated usage. The battery pack management system determines optimal charging parameters to enhance pack performance and cycle life while meeting desired range requirements. It calculates target charge levels based on anticipated driving distances and weights user inputs versus actual usage. This allows balancing range and cycle life by tailoring charge profiles to individual user needs.

Source

Flexible management system and method for efficiently operating stationary rechargeable batteries to extend lifetime and decrease costs. The method involves operating the battery in a usage mode during active energy consumption periods and a storage mode during inactive periods. In the usage mode, the battery is charged to a higher state-of-charge (SOC) for higher power, while in the storage mode, it is charged to a lower SOC to minimize degradation.

Source

Adaptive battery charging for electric vehicles to reduce cost and extend battery life. It involves charging the battery based on context like electricity rates and vehicle usage patterns. The charging algorithm adapts the charge level and capacity based on factors like cheaper off-peak electricity, battery aging, and driving habits. This allows users to charge to lower levels during off-peak times to save cost, charge to higher levels before long trips, and maintain battery health by not overcharging. The system can also automatically switch to hybrid charging curves to extend range as battery degrades. Users can also select ranges to drive and have the charging adapt accordingly.

Source

Method to detect internal short circuits in battery packs containing multiple interconnected cells. The method involves monitoring specific data parameters during charging, comparing them against profiles indicative of internal shorts, and establishing an internal short state if the comparison meets certain conditions. This allows identifying short circuits within cells during charging, which is important to prevent hazardous conditions and performance degradation.

Source

Detecting and responding to internal short circuits in electric vehicle battery packs to prevent excessive heating and thermal runaway. The detection method involves monitoring voltage patterns across series-connected battery cells to identify imbalances that indicate internal shorts. If contiguous cells uniformly drop voltage consistent with overcurrent, it indicates an internal short. This allows detecting shorts between cells without fuses, as they are below the fusing threshold. The response is activating maximum cooling to prevent heating until the short clears. This allows discharging the affected cells to prevent thermal runaway.

Source

Detecting and responding to low voltage electrolysis in electric vehicle battery packs to prevent hazardous hydrogen gas buildup. The system uses sensors like hydrogen, voltage, current, and immersion sensors inside the battery pack to detect conditions indicative of low voltage electrolysis. If electrolysis is suspected, the system can activate remediation measures like stopping the battery charge/discharge, purging flammable gases, and adding inert gas to displace oxygen. This mitigates the risk of hydrogen accumulation from coolant leaks or other conductive fluid ingress.

Source

Early detection of thermal events in individual battery cells to prevent propagation of thermal runaway in battery modules. An optical pyrometer inside the battery module detects short wave radiation density increases indicative of a cell becoming too hot. This allows mitigation measures like full cooling or power reduction to be initiated before widespread thermal runaway. The pyrometer can be placed anywhere in the module since radiation from all cells reflects internally.

Source

Intelligent architecture for electric vehicle battery packs that can selectively disconnect faulty cells with weak shorts. The architecture involves connecting an electronically controlled switch in series with each cell and using embedded processors to monitor the cells. By tracking the balancing time for each cell group, weak shorts can be identified. The processor then opens the switch for the faulty cell to isolate it from the pack. This allows bad cells to be selectively removed without disassembling the pack.

Source

Detecting and responding to exceptional charge events in series-connected battery packs to prevent overcharge and overdischarge. The system uses two detection modalities: steady-state analysis of charge-dependent parameters like voltage and impedance, and transient analysis during charging and discharging to detect deviations from normal behavior. If an exceptional charge event is detected, responses like preventing further charging, increasing cooling, or service intervention are triggered to mitigate potential hazards.

Source

Detecting and remediating exceptional charge states in individual battery elements of a series-connected battery pack. The technique involves monitoring charge-dependent parameters during operation to establish characterizations for each element. If a selected element's characterization shows an exceptional charge pattern during operation, it indicates an imbalance. This detects charge anomalies that voltage monitoring misses. Responses to exceptional charge events include preventing charging, increasing cooling, and limiting charging cycles.

Source

Detection and remediation of exceptional charge states in battery packs with series-connected cells. The system detects excessive overcharge or overdischarge of individual cells in a pack beyond normal limits. It uses two types of charge event detection: one for steady state charging and one for transient charging. For steady state, statistical analysis of cell parameters is used. For transient, deviations in cell impedance during discharge are monitored. If an exceptional charge event is detected, responses like preventing charging, reduced cooling, or service are taken to mitigate risks like thermal runaway.

Source

Detecting and responding to exceptional charge events in series-connected battery packs to prevent overcharge and overdischarge of individual cells. The system uses two charge imbalance detection methods, one for steady-state and one for transient operations. If a cell imbalance is detected, steps are taken to reduce it. If an exceptional charge event is detected in a cell, different remediation actions are initiated to mitigate the risk. These include preventing further charging, increasing cooling, and limiting charging until servicing.

Source

Monitoring and reporting electric vehicle (EV) charging disruptions to notify users when charging is unexpectedly interrupted. The system detects charging initiation, monitors charging operation, and issues a command to a notification system if charging disruption is detected. The notification instructions specify conditions for authorized disruptions like user proximity, full charge, or safe zone. This allows differentiating between planned and unplanned disruptions. The system notifies users of unplanned disruptions to enable prompt remediation.

Source

Efficiently fast charging electric vehicle batteries by preconditioning the battery cells before charging to improve charging efficiency. The method involves predicting if an upcoming charge will be fast or slow, and if fast, adjusting the battery cell temperature above the standard operating temperature. This is done by identifying an impending fast charge opportunity and using that information to prepare the battery cells for the fast charge by raising their temperature above the normal operating temperature. This improves fast charging efficiency compared to trying to cool the cells during fast charging. The technique involves a charge prediction system that identifies upcoming fast or slow charges, and an environment control system that adjusts the battery cell temperature based on the prediction.

Source

Automated method and apparatus for low temperature fast charging of lithium-ion battery packs to enable fast charging at cold temperatures without risk of lithium plating. The method involves periodically monitoring critical parameters like cell temperature, state of charge, and current to determine if fast charging is safe. If conditions allow, fast charging is used. Otherwise, slower charging is used. This allows fast charging at low temperatures without disabling it completely. The charging rate scales dynamically based on the critical parameters.

Source

External thermal conditioning system for electric vehicles that provides active cooling or heating of the vehicle's battery pack during charging to maintain optimal operating temperatures. The charging station detects the battery's thermal information and provides customized thermal conditioning through connections like fluid loops, air intakes, or contact pads. This allows external cooling during fast charging when internal systems can't keep up, or heating to bring the battery up to a required temperature. It enables more efficient and flexible charging by supplementing the onboard cooling system.

Source

Fast charging lithium-ion batteries to reduce charging time without degrading cycle life. The charging process involves multiple stages with adjustable voltages and currents based on factors like cell state-of-charge, temperature, and internal resistance. This allows fast charging without excessive voltage or current levels that can damage the battery. The stages are: 1) initial constant current with increasing voltage, 2) intermediate stages like constant voltage, constant current, or decreasing current, 3) final constant voltage with decreasing current. The intermediate stages are selected based on resistance, SOC, and temperature to prevent overcharging or plating. The adjustable profile compensates for resistance changes and reduces degradation compared to fixed two-step CC-CV charging.

Source

Charging system for electric vehicle batteries that improves utilization of available AC power during onboard charging. The system uses AC current sensing and control to maximize charging efficiency by adjusting the DC charging current based on real-time AC power availability. It establishes a maximum DC charging current based on AC power and controls the charger to provide the actual DC current. This allows full use of the AC power versus conservatively assuming DC efficiency.

Source

Battery cell design to prevent cell rupture during thermal runaway by efficiently releasing hot gas and debris through the cell cap. The design involves creating a specialized ejectment structure in the cell cap that responds to specific combustion properties of the electrode materials. This structure provides an aperture to direct combustion gases and debris out of the cell in a controlled manner, reducing the likelihood of side wall perforation compared to conventional cells. The ejectment aperture is created by responding to preselected combustion properties like temperature and pressure. This allows hot gases to escape the cell through the cap rather than penetrating the side walls.

Source

A system for safely disconnecting the high voltage battery of an electric vehicle in the event of a crash. It uses a pyrotechnic switch instead of an inertial switch to decouple the battery. The pyrotechnic switch has a pre-activated state allowing normal battery operation. But upon receiving a collision signal from the airbag system, it activates to sever the battery connection. This prevents unnecessary battery decoupling for minor collisions while ensuring decoupling for severe crashes.

Source

Detecting thermal events like thermal runaway in battery packs using pressure data analysis. The method involves dividing pressure data into sets, detecting anomalies, fitting curves to trailing edges, and checking time constants. If an anomaly's trailing curve fits an exponential decay with a certain time constant range, it indicates a thermal event. This helps distinguish true thermal events from false positives caused by vibrations or noise. The system also checks curve goodness of fit. If a thermal event is detected, it triggers an appropriate response.

Source

Battery pack design to improve reliability, durability, and cooling for applications like electric vehicles. The pack sandwiches batteries between rigid substrates that distribute force to prevent crushing. Conductors draw power and connect parallel/series between the batteries. Holes in the substrates prevent shorting. Cooling is via air blown through the pack and interconnected cooling tubes. The pack shape closely fits space, reducing wasted area.

Source

Early detection of thermal events in batteries to prevent propagation and mitigate damage. The system monitors the electrical isolation resistance of a battery pack. If the resistance drops below a threshold, indicating cell failure, the system responds to contain the failure. The response can be a warning, reducing load, increasing cooling, or activating fire containment. The system also tracks the isolation resistance fall and recovery to distinguish between initial venting and subsequent runaway.

Source

Thermal management system for electric vehicles that allows continuous and optimized control of battery cooling and passenger cabin cooling. The system uses a bypass valve in the coolant loop that allows splitting the coolant flow between going through the heat exchanger and bypassing it. This allows independent regulation of the amount of coolant going through the heat exchanger versus bypassing it. By adjusting the bypass valve, the system can fine-tune the cooling of the battery pack and passenger cabin to maintain desired temperatures within preset ranges. It also provides flexibility to balance cooling demands when the compressor output of the refrigeration system cannot be increased further. The bypass valve also allows bypassing the heat exchanger entirely for very low battery pack temperatures, further optimizing cooling.

Source

Integrating a heat exchanger into the base plate of an underfloor battery pack in an electric vehicle. The heat exchanger is thermally coupled to the batteries when the pack is in operation. When the pack is not in use, the heat exchanger is decoupled from the batteries. This allows optimal heat transfer from the pack to the ambient air flowing over the exposed base plate during vehicle motion. An integrated heat exchanger like this provides efficient cooling without stacking multiple heat exchangers, reducing power losses and improving performance.

Source

Improving the manufacturing process of lithium-ion cells by using a liquid-based thermal system for accelerating chemical reactions, capacity testing, and OCV measurement during cell assembly and formation. The cells are stored in contact with circulating liquid at elevated temperatures to initiate and accelerate chemical reactions. After initial charging/discharging, open circuit voltage (OCV) testing is done at high and low temperatures. Cells are then cooled and tested again. Finally, capacity testing is performed. This sequence allows accurate detection of defects using OCV and capacity tests. The liquid thermal system provides even temperature distribution, faster reaction times, and more accurate capacity measurement.

Source

Efficiently controlling the temperature of an electric vehicle battery pack to extend battery life without excessive cost. After the vehicle is turned off, a method actively cools the battery pack using techniques like pumping coolant through loops or operating refrigeration systems. Temperature thresholds and SOC ranges are used to select the cooling implementation. This prevents overheating when the vehicle is idle.

Source

Cooling manifold assembly for battery packs that improves manufacturability and performance compared to conventional cooling systems. The assembly uses a flexible thermal interface layer with deflectable fingers between adjacent cell rows and a contoured coolant tube. This allows easier assembly compared to rigid spacers and prevents shorting. The fingers conform to the cell shapes, providing better heat transfer while avoiding electrical contact. The flexible interface layer also prevents damage during cell insertion/removal. The contoured tube matches cell curvature.

Source

Intentionally inefficient operation of an electric motor in cold weather to enhance vehicle performance by generating excess heat. The motor controller has two modes: an optimal efficiency mode and a dissipation mode. In the optimal mode, the motor operates at maximum efficiency to conserve energy. But in cold weather, when battery power is limited, the dissipation mode is selected. This involves operating the motor at lower efficiency to intentionally dissipate excess power as heat. The extra heat warms the vehicle's electronics and battery, mitigating cold weather performance degradation.

Source

Optimizing electric vehicle (EV) charging rate based on user needs to balance fast charging speed with battery life and cost. The charging system determines optimal charging profile based on factors like state of charge (SOC) and time constraints. If fast charging is not required to meet SOC and completion time targets, it slows down charging rate to improve battery life and cost. This allows users to prioritize convenience vs longevity when charging.

Source

System for optimizing metal-air battery packs by capturing and reusing the oxygen-rich exhaust during charging to supplement air intake during discharging. The system has a compressor between the battery pack outlet and a gas tank inlet. During charging, the compressor compresses the oxygen-rich exhaust and stores it in the tank. During discharging, the compressed oxygen is fed back into the battery pack. This recycles the oxygen and reduces the need for external air, avoiding excessive oxygen levels during charging. The system also has valves to isolate the battery pack from external air during charging/discharging.

Source

Optimizing the power source of an electric vehicle with two different types of batteries, one metal-air and one non-metal-air, to balance efficiency and range. The optimization involves determining optimal split between the battery packs to minimize use of the less efficient metal-air pack while providing enough power for the expected distance. It also sets acceleration limits based on battery SOC and vehicle efficiency. The optimization considers factors like SOC, efficiency, distance, environment, weather, driver, and itinerary.

Source

Mitigating thermal runaway in battery packs to prevent cascading cell failures and contain the thermal energy release. The system uses fluid-filled conduits around the cells that breach at lower temperatures than the cell materials. When a cell enters thermal runaway, the breach allows fluid to discharge onto the overheating cell, cooling it and nearby cells. This helps prevent propagation of thermal runaway. The fluid can be pumped or from a source, and sensors monitor pressure, temperature, and fluid level.

Source

Battery pack design to mitigate thermal runaway propagation in case of internal short circuits. It involves selecting one cell in the pack to be the last one to short circuit by using a higher temperature safety mechanism in that cell. This cell is then thermally isolated from the others using a barrier like ceramic enclosure, coating, or filler. This prevents excessive heating and collateral damage if the isolated cell shorts, as the barrier insulates it from the rest of the pack. The other cells still have their regular short circuit safety mechanisms.

Source

Battery pack design to mitigate thermal runaway hazards by guiding hot gases and debris away from the pack and vehicle during runaway events. The pack has a venting assembly with valves covering exhaust ports. During normal operation, the valves seal. But if pressure rises due to battery runaway, the valves unseal and gas escapes through the ports. An angled duct inside the pack guides the escaping gases away from the pack and vehicle. This prevents gas and debris from spreading inside the pack or vehicle, reducing collateral damage and propagation risks.

Source

Battery design to prevent thermal runaway propagation in battery packs. The battery assembly has a layer of intumescent material coating the cell casing sidewalls and bottom, excluding contact regions near the cap and bottom. The intumescent material absorbs heat, expands and hardens to contain thermal events and prevent cascading failures. It provides thermal insulation, contains gases and flames, and directs heat away from adjacent cells. The intumescent material is biologically inert, electrically non-conductive and has a set temperature above typical cell operating temps.

Source

Dispersing heat from battery cells to prevent chain reactions and failures. The method involves surrounding and contacting a portion of the cell cases and the cooling tubes with a thermally conductive material. This allows heat from a thermal event in one cell to be transferred to adjacent cells and the cooling liquid, preventing a chain reaction. The cells are arranged with offset rows and the cooling tubes between them. The thermally conductive material solidifies around the cells after application.

Source

A system for allowing controlled cooling of electric vehicle battery packs during internal thermal events. The system provides a way to ingress coolant like water into the sealed battery enclosure during thermal runaway conditions. This allows direct contact with the affected cells to remove heat and mitigate chain reactions. A specialized fill port is used for normal coolant refilling. But in emergency situations, a perforation tool can breach the enclosure wall to allow coolant ingress through a specific hole. The tool has features to prevent unintended breaches. The hole location is also designed to minimize damage and contamination. The breach-and-fill method provides a controlled way for first responders to cool a battery pack in an urgent situation where normal coolant access is unavailable.

Source

Detecting and mitigating high voltage electrolysis within electric vehicle battery packs to prevent thermal runaway and hydrogen buildup. The system uses sensors to monitor for conditions like coolant leaks and bridged terminals that can lead to electrolysis. If electrolysis is detected, the system responds by cutting power to prevent further energy input, and actively cooling the electrolyzing area to prevent boiling and temperature rise. This prevents chain reactions and thermal runaway that can occur from electrolysis.

Source

A multi-port, multi-mode valve with multiple inlets and outlets for fluid like coolant. It has a single actuator that can selectively open or close fluid flow between pairs of ports while simultaneously not affecting flow between other pairs. The valve uses a stemshell component as the actuated valve to regulate operational modes.

Source

Redundant function performance in the communications and data transmissions of energy storage systems using a looped communications medium. The looped medium connects nodes in the energy storage system. Each node has redundant devices for communication and data transmission using the looped medium. The devices can operate simultaneously on the same medium segment without interference. The looped medium allows redundant communication even if segments are disrupted. Passive frequency division multiplexing allows simultaneous operation without interference. The looped medium termination allows indeterminate reception detection. The redundant devices mitigate failure impacts on each other.

Source

Scalable, modular energy storage system that allows parallelization of multiple battery blocks with different cell types, ages, and voltages without requiring exact voltage matching. The system uses galvanic isolation and power electronics converters for each battery block to provide a common DC interface. This allows failure independence, scalability, and parallelization of dissimilar batteries without propagation or system-wide voltage balancing.

Source