Electrification of powertrain products by major suppliers including BorgWarner

SAE Exposition 2018: EV and HV systems including eAxle, eDrive, PCU, and battery

2018/07/11

Summary

EV Powertrain of Nissan LEAF
(JSAE Exposition 2018)

This report covers some of the key products and technologies, developed in response to the increase of EVs and HVs in the vehicle line-up of automakers, that were exhibited by Tier 1 suppliers at the JSAE Automotive Engineering Exhibition 2018 (period: May 23 to 25, 2018, venue: Pacifico Yokohama).

Electric axle (eAxle) systems integrating the transmission for electrified vehicles with the electric motor can be, for example, easily mounted on the rear axle in combination with an electric 4WD system to electrify the platforms of vehicles produced for the mass market. Electric drive (eDrive) systems, consisting of an electric motor and inverter, can be applied not only to the drive systems of 48V hybrid vehicles (HV) being introduced mainly in Europe, but also as the drive motor for small EV mobility solutions.

For the power control unit (PCU) comprised of devices such as the inverter, DC/DC converter and car charger, technologies were introduced to efficiently utilize battery energy as well as to achieve size and weight reduction, and high output. A SiC (silicon carbide) power device mounted on the inverter was also exhibited.

Optimized battery materials (e.g. cathodes, anodes, separators) are being developed for lithium ion batteries, the mainstream battery technology for EVs, to improve energy density and capacity to extend range as well as to improve battery performance in areas such as safety, longer battery life, and fast charging. Also, materials required to reduce the weight of battery packs that were introduced by chemical manufacturers included high-performance plastics having excellent properties such as heat resistance, heat dissipation, and insulation properties.



Related reports:
JSAE Exposition 2018: CASE Technologies of System Suppliers (Jun. 2018)
Transmission.tech 2018: Technologies for Future Mobility (May 2018)
WCX18: SAE World Congress Experience - Clean Vehicle Technology (May 2018)
TECHNO-FRONTIER 2018: Manufacturing changes in the age of electrification and autonomous driving (May 2018)





eAxle: BorgWarner, ZF, Schaeffler, and Univance

To respond to the growing lineup of EVs and HVs in the product portfolio of automakers, suppliers exhibited electric axle (eAxle) drive systems that integrate the 1st and 2nd speed gear sets of EV transmissions with the electric motor. The eAxle drive systems are highly efficient gear boxes that make it easy to electrify car production platforms for the mass market because they can be scaled to the various sized motors used for numerous applications such as small cars, large passenger cars, and commercial vehicles by the adoption of features including electric 4WD rear axles.



BorgWarner: "eDM" electric drive module

BorgWarner's "eDM" electric drive module solution integrates its "eGearDrive" EV transmission and its "HVH 250" electric drive motor in a lightweight and compact package. The eDM is a system for EVs and P4-type HVs (layout on rear shaft) and has been adopted for the Mitsubishi Fuso "eCanter".

The eGearDrive transmission is scalable to motors of various sizes, adopts a highly efficient helical gear, and contributes to extending the range of EVs. Instead of conventional round wire windings, the HVH250 motor uses precision-formed rectangular wires and multiple layers of interlocking “hairpins”. The high voltage hairpin (HVH) technology enables the HVH250 motor to produce up to 425 Nm of torque and 300 kW of power at 700 volts, with a more compact design and higher output.

"eDM" electric drive module Left: P2 transaxle module
Right: Motor drive chain, adopted for Suzuki "Solio Hybrid"
Inverter

 

P2 transaxle module

The P2 transaxle module (transmission axes parallel to the spindle) for HVs enables various hybrid clutch functions such as pure EV drive, stop-start, and regenerative braking, as well as a reduction in CO2 emissions and provides high power density. The module can be easily mounted on various drive trains, and is compatible for both 48V mild hybrid as well as conventional hybrid applications.

 

BorgWarner EV product lineup BorgWarner HV product lineup



ZF: "mSTARS" Modular Semi Trailing Arm Rear Suspension

ZF exhibited its "mSTARS" rear axle system that contributes to space savings. The system integrates the interfaces such as electric motors, gear drives, differentials, and power electronics. It can be used in combination with conventional 4WD modules as well as adopted for electrified vehicle applications such as EVs, HVs, and FCVs. Only minor modifications to the car body are required for installing the mSTARS system in vehicles in lieu of conventional axles. The mSTARS system is designed to be easily converted to the electrified platforms of vehicles produced for the mass market, with a single body type able to satisfy various market requirements.

"mSTARS" Modular Semi Trailing Arm Rear Suspension Advanced integrated electric central drive 48V compatible integrated starter generator (iSG48)
Display Panel

 

Advanced integrated electric central drive

The electric motor achieves a compact design by integration of the 2-stage 1st speed transmission, the differential, and the power electronics.
ZF demonstrated its "CeTrax" electric central drive for electric-powered city buses in October 2017. The system can be mounted on low-floor bus axle platforms.

 

48V compatible integrated starter generator (iSG48)

The module integrates the inverter and power electronics into the transmission housing and can be mounted with any type of drivetrain. The ISG system enables HV features such as torque assist when accelerating, and engine idling start/stop.



Schaeffler: One speed coaxial electric axle

Schaeffler exhibited an electric axle that couples the electric motor with the transmission. The gears sets have been established for the 1st and 2nd gears. The compact and lightweight coaxial transmission is based on a planetary reduction mechanism and Schaeffler’s lightweight differential mechanism. The modular design with its selectable transmission ratio (8.5 to 10.5) contributes to high cost-effectiveness and cost reduction. The design concept can be combined with an optional parking lock. It can be mounted as an electric 4WD rear axle or in the front as an FF axle.

One speed coaxial electric axle
adapted for Audi e-tron
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3K hybrid module triple clutch
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3K hybrid module

This module combines a thin motor and triple clutch that is located between the engine and the transmission.



Univance: Gearbox for EV/HEV

Univance exhibited a system that combines two small motors with the 2nd speed gearbox. This design enhances the high efficiency operating range compared to 1 motor type gearboxes, improving high speed driving performance. Power consumption is also reduced. As a compact, lightweight, low friction, and high efficiency gearbox, Univance is targeting this product for adoption on minicars, passenger cars, and SUVs, and is also considering its adoption on large buses and heavy duty truck applications in the future. By matching the mass-produced motors to the vehicle classifications to control costs, the company will be able to provide a series of inexpensive and highly efficient gearboxes.

Gearbox for EV/HEV
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48V add-on simple hybrid system
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Electric Drive (eDrive) systems: Mitsubishi Electric, Magna, Valeo, and Mahle

A number of suppliers exhibited electric drive (eDrive) systems that consist of an inverter configured to control the electric motor. The systems are supplied mainly for the drive systems of 48V hybrid vehicles in Europe and also can be adopted as the drive motor of low-speed EVs, such as small mobility vehicles.

Suppliers have developed eDrive systems with more compact designs, higher output, and improved ease of installation that can be adopted for a wide range of electrically powered vehicles. By equipping a vehicle with an eDrive system, electric 4WD and limited zero emission drive tailored to the battery size of each vehicle becomes possible. Valeo and Mahle have equipped their own EV demo cars with 48V systems, and Mitsubishi Electric's 48V system has been adopted for the new generation inline-six gasoline engines in the Mercedes-Benz S-class.



Mitsubishi Electric: ISG system for 48V hybrid vehicles

Mitsubishi Electric developed the integrated starter-generator (ISG) system for 48V hybrid vehicles. It consists of motor and an inverter that controls the motor. The ISG system is a crankshaft direct-driven system that achieves higher output power and improved power generation than conventional belt-driven systems, contributing to better fuel efficiency in 48V hybrid vehicles.

By using Mitsubishi Electric’s original split core winding technology for the motor, high density winding can be realized even with thick coils. This technology realizes a thin-profile, high-power motor that adapts flexibly to various vehicle layouts. A transfer-molded power module is adopted as an inverter for 48V systems. An optimally designed cooling unit enhances cooling performance to realize a compact, highly reliable inverter.

ISG system for 48V hybrid vehicles
Adopted for the new generation inline-six gasoline engines in the Mercedes-Benz S-class
Display Panel
Power devices for EV/HEV
Display Panel: J1-Series / Evaluation Kit / T-PM



Magna: Highly integrated electric drive system

Magna's highly integrated electric drive system has a coaxial design integrating the countershafts, induction motors and inverters, and oil and water cooling into a single unit. The system is used for 4WD modules and is installed in HV and small EV applications.

Highly integrated electric drive system
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48V torque auxiliary electric axle
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48V torque auxiliary electric axle

The system integrates the electric motor, control software, temperature management system, and detachment mechanism. Noise and vibration (NVH) performance has been improved at low speeds and during coasting.



Valeo: 48V electric rear axle drive "eRAD 48V"

Valeo's 48V electric rear axle drive eRAD technology consists of a high efficiency motor and inverter. Combined with its 48V belt-driven starter generator (48V BSG), 4WD operation in electric mode and limited zero emission drive are possible, depending on battery size. The motor can be used for P4-type hybrid vehicles (layout on rear shaft), as well as the drive motor for low-speed EVs. It was installed in Valeo’s EV demo car exhibited at the CES 2018.

 

High power electric drive system

The system incorporates an inverter and speed reducer into an electric motor. Electric 4WD operation is realized by mounting the system on the rear axle and connecting it with the electronic devices mounted on the front axle. The system realizes 4WD operation without using the mechanical parts necessary for 4×4 transmissions. The system is installed in the Volvo S90 and XC90 T8 plug-in hybrid.

Left: 48V electric rear axle drive "eRAD 48V"
Right: DC/DC converter
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High power electric drive system Water cooled battery cooler
Display Panel

 

Water cooled battery cooler

The battery cooler utilizes the space between the cells of cylindrical lithium ion batteries. By placing the corrugated cooling plates at the surface of the battery cells, the contact area is maximized and cooling efficiency improved.



Mahle: 48V driving motor for mild hybrid

Mahle’s IPM (Interior Permanent Magnet Synchronous Motor) traction drive is a combination of a permanent magnet synchronous motor and integrated 48V system. It was installed in the MEET (Mahle Efficient Electric Transport) 48V concept car for urban mobility announced in 2017.

Mahle EV products 48V drive motor for mild hybrids Car charger





Power control unit (PCU): Calsonic Kansei, Keihin, and Rohm

The power control unit (PCU) is mounted in the engine room and configured with devices such as the inverter, DC/DC converter, and car charger. As PCUs become smaller and lighter, increased output power is required to yield high power performance.

Calsonic Kansei and Keihin exhibited PCUs that have realized compact packaging. Integration technology for some of the PCU's core elements such as the inverter and electronic control unit allow for more compact and lightweight designs to expand the interior space and improve fuel economy.

Inverters for EV and HV applications require technology to efficiently utilize battery energy. Rohm exhibited its SiC (silicon carbide) power device mounted on the inverter used in Formula E racing vehicles as a technology to realize weight reduction, miniaturization, and satisfy the high load requirements of inverters.



Calsonic Kansei: Power control system

Calsonic Kansei's power control system integrates the inverter, DC/DC converter, charger, and quick charge relays. Miniaturization is realized by integrating coolers and sharing capacitors.

Electrical energy management system
Display Panel
Electrical energy management roadmap

Power control system
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Lithium-ion battery controller



Keihin: Power control unit (PCU)

Keihin's PCU achieves miniaturization with high output (output density 4.3 kVA/L). The PCU can be mounted directly onto the transmission using a vibration resistant design, thus contributing to a reduction in the number of parts.

Power control unit (PCU)
Adopted for Honda Accord
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Battery Management System (BMS)
Display Panel: 1 / 2
Cell voltage sensor
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Management electronic control unit
Display Panel

 

Management electronic control unit

This system transmits the necessary information to the PCU based on information obtained from the battery management system (BMS) and the degree of accelerator opening. By using a common electronic control unit for EV and gasoline cars applications, the control unit can be adopted for various types of powertrains.



Rohm: SiC power device

The Rohm booth featured a Formula E display that showed the transition to full SiC power modules for the inverter. Rohm emphasized that it was able to reduce the power device’s weight by 6 kg and its size by 43% from season 2 to season 4 of the Formula E hybrid racing circuit.

SiC technology used in the Formula E SiC products

 

Rohm is the official technology partner of the Venturi Formula E team (Venturi Automobiles) who participated in the FIA Formula E Championship 2017-2018 (Season 4) electric car race, providing its inverter SiC (silicon carbide) power device. In season 2, the IGBT (Insulated Gate Bipolar Transistor) with power transistor used an inverter weighing 15 kg with an output of 200 kW, but in season 3 by using its SiC SBD (Schottky barrier diode) the weight of the inverter was reduced to 13 kg with 200 kW of output, while in season 4 it was able to realize a lightweight, compact and high-load device using its full SiC module in which the weight of the inverter was reduced to 9 kg with an output of 220 kW.





Battery: Toshiba, JTEKT, Toyota Boshoku, and NTK

Lithium ion batteries, the mainstream battery technology for EVs, are required to have improved energy density and capacity to extend range as well as to improve battery performance in areas such as safety, battery life, and fast charging. To meet these needs, battery makers are promoting the research and development of more efficient battery materials (e.g. cathodes, anodes, separators).

At this exhibition, Toshiba exhibited batteries that adopt oxide-based materials for the cathodes. NTK Spark Plug Co., Ltd. exhibited all-solid-state batteries that use oxides as electrolytes. Although batteries using sulfides may generate harmful gases, oxides are said to be free of such risk and very safe.

Toyota Boshoku developed a lithium-ion secondary battery featuring its own separator, stating that it has achieved both an energy density comparable to lithium ion batteries for HV applications and a high output comparable to that of capacitors. JTEKT is developing a highly heat-resistant lithium ion capacitor to be used as an auxiliary power source for electric power steering (EPS) in automobiles and for other applications. In the future, JTEKT plans to apply this technology to the development of lithium ion secondary batteries.



Toshiba: Industrial lithium ion secondary battery "SCiB"

The industrial lithium ion secondary battery "SCiB" of Toshiba Infrastructure Systems & Solutions Corporation is used for automobiles, buses, railways as well as industrial equipment such as elevators and infrastructure such as power plants. An oxide material (lithium titanate) is adopted for the negative electrode (cathode). The SCiB has a life of over 20,000 charges/discharges, is capable of quick charging in 6 minutes, has an input/output density comparable to capacitors, and can be operated at temperatures as low as minus 30 degrees C. As a result, it has exceptional performance with regards to safety, long battery life, low temperature performance, fast charging, high power input/output, and high input/output capacity.

Industrial lithium ion secondary battery "SCiB" Silicon nitride insulating heat dissipation substrate
Si3N4 substrate for PCU

 

Silicon nitride insulating heat dissipation substrate

Silicon nitride (Si3N4) is a high performance material that has been used for applications such as the space shuttle and wind power generation due to its mechanical properties of high strength and high toughness. Semiconductor power modules configured with PCUs mounted on the inverter in EV and HV applications are required to have high insulation and heat dissipation properties, requiring the development of insulating substrates with high thermal conductivity. Insulating substrates are generally classified as either a resin substrate or a ceramic substrate (alumina, aluminum nitride, silicon nitride). Until now, alumina and aluminum nitride have been mainly used for insulating substrates, but Toshiba has replaced these materials with the silicon nitride substrate it has developed because of its high thermal conductivity. The silicon nitride ceramics substrate of Toshiba Materials is one of the world's best ceramic materials for heat dissipation and strength.



JTEKT: Highly heat-resistant lithium ion capacitor and lithium ion secondary battery

At the front of its booth, JTEKT exhibited its highly heat-resistant lithium ion capacitor. JTEKT originally developed the capacitor as an auxiliary power source for its electric power steering (EPS) system, but has been receiving an increasing number of inquiries for other applications such as for construction machinery. The company is strengthening its in-vehicle power device business, and plans to start the production of highly heat-resistant lithium ion capacitors at its existing plant in Japan from April 2019.

Highly heat-resistant lithium ion capacitor
Module
Display Panel: 1 / 2 / 3 / 4
Auxiliary power supply system for EPS
Backup power supply unit
Rack Parallel type EPS
Display Panel
Highly heat-resistant lithium ion secondary battery
Display Panel

 

JTEKT's highly heat-resistant lithium ion capacitor can be used in temperature environments of minus 40 to plus 85 degrees, and since a cooling system is unnecessary it can save space in the design of products.

In addition, the company plans to apply the technologies it developed for the capacitor to the development of lithium ion secondary batteries, which it will likely be able to bring to market by around 2021, with plans to license its technology to battery and battery material manufacturers.



Toyota Boshoku: Laminated lithium-ion secondary battery

This was the first time for Toyota Boshoku to exhibit its laminated lithium-ion secondary battery developed for next-generation automobiles. It features a separator that utilizes fine fiber and precision press processing technologies developed in-house, with an input/output density comparable to that of capacitors with the same energy density as the lithium ion batteries used for conventional HV applications. The company plans to promote the adoption of this battery for super sports cars and premium cars, which require high power.

Materials used for elements such as the cathode, anode, and electrolytic solution are similar to those used in the lithium ion batteries of common passenger vehicles, but elements such as the separators used to isolate the positive and negative electrodes are made using filtering technology as well as filtering and fine fiber manufacturing technology developed in-house. Moreover, in the case of a fuel cell stack, the company applies precision metal molding and precision press production technology. The company believes that it has improved input/output density due to the high performance of the separator, because among the three resistance components (ion resistance, reaction resistance, electronic resistance) generated in the battery, it is able to suppress the ion resistance of the lithium ions travelling between the positive and negative electrodes. In an HV equipped with a 1 kWh battery, the technology can assist to generate an output equivalent to 100 kW for 30 seconds during acceleration. In addition, the battery capacity is maintained at 99.9% of the initial performance even after 30,000 charge/discharge test cycles, equivalent to the life of a vehicle, demonstrating high reliability performance.



NTK: Solid-state battery

NTK exhibited a reference sample of its all solid-state battery. A conventional lithium ion battery uses a liquid organic solvent as the electrolyte, whereas an all solid battery uses an inorganic solid electrolyte. All solid-state batteries are expected to become the next-generation battery to extend the range of EVs, because safety is enhanced due to the absence of any danger of electrolyte leakage, and because the energy density can be improved to widen the operating temperature range.

Other companies developing all-solid-state batteries have adopted sulfide for the electrolyte, but NTK batteries will use sulfur-free oxide. In the case of sulfides, there is the risk of a reaction with moisture to generate harmful hydrogen sulfide gas, but the use of oxides will not result in the burning or generation of toxic gases. NTK has developed an oxide solid electrolyte based on chemical substitution technology that replaces some elements with another as well as sintering technology that makes the ceramic material dense and strong, technologies developed by NTK through years of experience in the ceramics business. NTK believes that the highest levels of lithium ion conductivity have been achieved with oxides.

Toyota Boshoku
Laminated lithium-ion secondary battery
Display Panel: 1 / 2 / 3
NTK
Solid-state battery
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Materials for lithium-ion battery packs: Mitsubishi Chemical, and Sekisui Chemical

Chemical manufacturers introduced highly functional plastics with excellent performance in areas such as in heat resistance, heat dissipation, and insulation to be used in the design of battery packs that are required to be lightweight.



Mitsubishi Chemical: Materials for lithium-ion battery packs

Mitsubishi Chemical exhibited materials for lithium-ion battery packs for EV applications. The company also introduced plastic resin products that have excellent properties such as heat resistance, heat dissipation, and insulation.

In addition, the company proposed the optimization of chemical combinations by conducting simulations for electrolytic solutions and negative electrode materials, which are main materials of lithium ion batteries.



Sekisui Chemical: Products for EV related parts

Sekisui Chemical introduced high performance plastic products for EV related parts such as the battery pack and ECU. The company introduced plastics for molded products used to suppress electromagnetic waves and minimize heat dissipation, which are concerns in the design of plastic battery packs, as well as products under development such as flame retardant acrylic tape and heat dissipation cushioning materials.

Mitsubishi Chemical
Materials for lithium-ion battery packs
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Optimization of electrolyte and anode materials
Sekisui Chemical
Products for EV related parts
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Keywords
electrification, EV, HV, hybrid, 48V, eAxle, motor, PCU, inverter, SiC, lithium-ion battery, battery, battery pack, solid-state battery, BorgWarner, Schaeffler, Mahle, Magna, ZF, Univance, Mitsubishi Electric, Keihin, Calsonic Kansei, Rohm, Toshiba, JTEKT, Toyota Boshoku, NTK, Valeo, Mitsubishi Chemical, Mitsubishi Chemical, Sekisui Chemical

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