In the dynamic landscape of electric vehicles (EVs), staying abreast of the latest technological advancements is pivotal. Our team, deeply entrenched in the EV industry, unveils the most crucial components defining these eco-friendly marvels’ prowess. Buckle up as we dissect the intricacies and unveil the driving force behind the EV revolution.
BMW’s electric vehicles (EVs) are designed with cutting-edge technology and incorporate several key components that contribute to their performance, efficiency, and sustainability. Here are some key components of BMW electric cars:
Electric Motor
The two primary types of Permanent Magnet Synchronous Motors (PMSMs) commonly used in electric vehicles (EVs) are interior and surface PMSMs. Both utilize rare earth magnets in the rotor field due to their high field strength (typically 0.9 to 1.2 Teslas) and resistance to demagnetization. However, rare earth magnets are expensive, and their demagnetization resistance decreases at elevated temperatures.
PMSMs offer advantages such as predictable torque at 0 RPM, but they face challenges with back electromotive force (EMF) limiting top speed. Field weakening, a method to increase speed, poses risks of demagnetization and uncontrolled generation, potentially damaging the motor and inverter components.
The alternative motor commonly used in EVs is the AC Induction Motor (ACIM). While cost-effective and robust, ACIMs face challenges in delivering high torque at low RPMs and have complex control schemes.
A less common motor, the Wound Rotor Synchronous Motor (WRSM), utilizes electromagnets for its field, eliminating some downsides of PMSMs. However, it requires power supplied to the field via slip rings and brushes. Unlike PMSMs, WRSMs can present a unity power factor to the inverter, reducing reactive current and associated losses.
The WRSM’s control scheme involves varying the field current based on torque demand, offering simplicity but lacking sophistication compared to PMSMs. Electromagnets in WRSMs can achieve higher field flux intensity than rare earth magnets, potentially reducing motor size.
However, challenges arise from the choice of materials for the stator and rotor, considering factors like AC losses and tensile strength.
Battery Pack
BMW’s i Vision Dee concept car, unveiled at CES 2023, showcases significant advancements in the automaker’s electric vehicle (EV) technology. The car is based on BMW’s Neue Klasse EV architecture, departing from traditional rectangular prismatic batteries to adopt large cylindrical-form-factor cells similar to Tesla’s “4680” cells.
The new battery cells, developed in collaboration with partners such as CATL and EVE Energy, feature dimensions labeled “4595” and “46120.” These cells boast at least 10% more active battery material within their metal cases and offer a 20% increase in energy density.
The batteries serve as structural, crash-resistant chassis members, allowing for flexible pack sizes ranging from 75 kWh to 150 kWh, with motor outputs spanning from 268 horsepower to an impressive 1341 hp (1000 kW).
The innovative “pack-to-open-body” design not only enables diverse applications but also reduces vehicle height by more than 10 mm, improving aerodynamics, lowering the center of gravity, and cutting costs. BMW aims to maximize mileage per cell rather than increasing battery size excessively.
The cylindrical cells, shielded against heat, can be individually monitored, minimizing the risk of thermal runaway and enhancing safety. This layout eliminates a modular structure, simplifies access to electronic controls, and addresses maintenance concerns.
In terms of chemistry, BMW employs an improved nickel-cobalt-manganese (NCM) chemistry, reducing cobalt content by 50% and utilizing 20% less graphite in the anode. Silicon content in anodes is increased to enhance efficiency and performance, with a bold claim of a 100% solid-state battery in a BMW Group model by 2030.
BMW’s Neue Klasse design supports not only nickel-rich cells but also lithium-iron-phosphate (LFP) cell chemistry for lower-end models. LFP offers cost advantages, safety, and durability without cobalt or nickel, contributing to a 30% increase in driving range.
The company adopts an 800-volt architecture, matching competitors like Tesla, Hyundai, and Kia, enabling 30% faster DC charging rates exceeding 200 kW.
As BMW plans to have 10 million EVs on the roads by 2030, the company is confident in its ability to scale up production. The new cells are expected to reduce battery costs by 50% at the pack level, contributing to the elusive goal of price parity between EVs and traditional internal combustion engine models.
BMW plans to establish six cylindrical-cell gigafactories globally, with partnerships and supply chain development focused on localized materials, including those from North America. This effort aligns with President Biden’s infrastructure law, linking EV tax breaks to local assembly and sourcing critical battery minerals.
Power Electronics
BMW’s fifth-generation powertrain, named eDrive, revolutionizes electric vehicle technology by integrating the electric motor, transmission, and power electronics into a single housing.
Notably, this design innovation eliminates the dependency on rare earth elements for the magnetics, contributing to resource sustainability.
In addition to the integrated powertrain design, BMW has implemented several key advancements:
- Reduced Traction Inverter Components
By leveraging built-in overcurrent detection and self-diagnostics in integrated circuits (ICs), BMW has successfully reduced the number of components in the traction inverter. This enhancement streamlines the powertrain system.
- Strategic Partnership with Scilab
BMW has chosen Scienlab as a strategic partner for the development of energy storage. This collaboration aims to advance the energy storage capabilities of BMW’s electric vehicles.
- Long-Term Supply Agreement with Onsemi
BMW has entered into a long-term supply agreement with Onsemi, a notable semiconductor solutions provider. This partnership involves equipping BMW Group’s upcoming electric drivetrains with Onsemi’s EliteSiC die, enhancing the efficiency and performance of the drivetrain.
- Utilization of a Novel British Power Inverter Tester
BMW has employed an innovative power inverter tester, sourced from British expertise. This testing approach ensures the reliability and functionality of the new power inverter, showcasing BMW’s commitment to rigorous quality control.
The electric motor featured in the BMW i3, a component of the fifth-generation eDrive powertrain, is specifically designed for urban environments, providing an impressive output of 125 kW/170 hp. This underscores BMW’s dedication to creating electric vehicles optimized for city traffic scenarios, sustainably combining power and efficiency.
Charging System
BMW is now offering the Wireless Charging option for the BMW 530e iPerformance, available for lease. This innovative technology allows electric energy to be transferred from the main supply to the vehicle’s high-voltage battery without the need for any cables.
The feature is currently applicable to the BMW 530e iPerformance model, with specific fuel consumption and CO2 emission figures in the legislative EU test cycle.
BMW Wireless Charging is designed to simplify the charging process for electric vehicles. The system comprises an inductive charging station (GroundPad) that can be installed either indoors or outdoors, and a secondary vehicle component (CarPad) affixed to the underside of the car.
Energy is transferred contactlessly over a distance of approximately eight centimeters. The GroundPad generates a magnetic field, inducing an electric current in the CarPad, subsequently charging the high-voltage battery.
The system boasts a charging power of 3.2 kW, allowing the BMW 530e iPerformance’s high-voltage batteries to be fully charged in around three-and-a-half hours.
With an impressive efficiency rate of about 85 percent, the BMW Wireless Charging System represents a significant step toward creating an infrastructure that rivals the convenience of refueling traditional combustion engine vehicles. Customers can opt for this technology, enhancing the overall charging experience for electrified vehicles.
Regenerative Braking
BMW’s Brake Energy Regeneration system is designed to enhance efficiency by converting kinetic energy into electricity, which is then stored in the vehicle’s battery. This process occurs specifically when the car is braking, decelerating, or coasting.
Notably, the alternator is disengaged from the drivetrain during acceleration and, whenever feasible, during other driving scenarios. This unique feature contributes to both improved fuel economy and enhanced overall performance.
Regenerative braking, a key element of this system, is a prevalent mechanism in most hybrid and fully electric vehicles. Its primary function is to capture and store energy during braking, reducing the reliance on conventional engine power. This, in turn, leads to a decreased consumption of gasoline, offering cost savings to the driver.
It’s worth noting that BMW plug-in hybrids also incorporate regenerative braking functionality, albeit to a lesser extent compared to fully electric vehicles. In these hybrids, energy is stored when the brakes are applied. However, the primary source of charging for plug-in hybrids is through external means—plugging the vehicle into a power source.
This dual approach allows BMW plug-in hybrid drivers to benefit from both regenerative braking and the convenience of charging their vehicles externally, providing a versatile and efficient driving experience.
As electric vehicles redefine the automotive landscape, staying informed about the core components is paramount. Our insightful exploration sheds light on the pivotal elements shaping the future of EV technology. Join us on this journey towards a sustainable and electrifying future.