The electric drive system has emerged as the primary decision-making factor for new energy vehicle (NEV) buyers, surpassing range anxiety. According to Sina Mobile News, China’s NEV passenger vehicle electric drive installations reached 9.89 million units in 2025, with the…
How to Choose an NEV Electric Drive System? Deep Dive into 3-in-1, Coaxial, and Multi-in-1 Technologies + FAQ
Type: News Repost
The electric drive system has emerged as the primary decision-making factor for new energy vehicle (NEV) buyers, surpassing range anxiety. According to Sina Mobile News, China’s NEV passenger vehicle electric drive installations reached 9.89 million units in 2025, with the market value surging from RMB 30 billion in 2020 to RMB 120 billion in 2024. This article provides a comprehensive technical breakdown of current mainstream architectures, comparing permanent magnet synchronous motors, coaxial layouts, and multi-in-one integration platforms. It also examines the industry shift toward 800V high-voltage architectures paired with silicon carbide (SiC) inverters and advanced oil-cooling solutions. By analyzing performance metrics, cost structures, and spatial efficiency, the piece offers targeted procurement and purchasing recommendations for passenger vehicles, commercial fleets, and high-performance applications. Readers will also find a practical FAQ section addressing maintenance, cost-benefit analysis, and technology selection. The analysis is based on publicly available industry data and technical specifications.
> This article is republished by AIC Engineering. Copyright belongs to the original author. The original link is provided at the end under "Sources".
The electric drive system has replaced driving range as the primary battlefield in NEV purchasing decisions. According to Sina Mobile News, China’s NEV passenger vehicle electric drive installations reached 9.89 million units in 2025, with the electric drive market size surging from RMB 30 billion in 2020 to RMB 120 billion in 2024. Currently, the mainstream choice is a "permanent magnet synchronous motor (PMSM) + 3-in-1 integrated system." For those prioritizing extreme spatial efficiency and performance, "coaxial electric drives" are the preferred option, while commercial heavy-duty trucks typically rely on "asynchronous motors + multi-speed reducers."
01 Motor Types:
PMSM Leads in Efficiency, While Asynchronous and Switched Reluctance Hold Specific Niches
The motor serves as the "heart" of the electric drive system. The passenger vehicle market is currently dominated by PMSMs, which boast efficiencies exceeding 97%, high power density, and compact dimensions that align with NEV lightweighting requirements. Under identical battery capacities, PMSMs deliver longer driving ranges and higher starting torque, providing the responsive acceleration familiar in urban commuting—a characteristic that asynchronous motors struggle to match.
AC asynchronous motors feature robust construction, lower costs, and high reliability, but their efficiency and power density are comparatively lower. They are primarily deployed in NEV commercial vehicles and highly cost-sensitive applications. Switched reluctance motors offer simple structures and wide speed regulation ranges, but their vibration and noise levels are relatively high, limiting their current use mainly to commercial buses.
Flat-wire winding technology is currently a key enabler for enhancing motor performance. Compared to traditional round wires, it increases the slot fill rate by 10%–20% and reduces copper losses by 15%, resulting in smaller and lighter motors. When combined with direct rotor oil-spray cooling, power density can increase by an additional 32%. For instance, the GAC Aion Quark Electric Drive M25 achieves a rotational speed of 22,000 rpm and a power density of 12 kW/kg, and has already been mass-produced and installed in vehicles.
Motor Type | PMSM | AC Asynchronous | Switched Reluctance |
|---|---|---|---|
Efficiency | >97% | Lower | Medium |
Power Density | High | Medium | Medium |
Cost | Higher | Low | Low |
Primary Application | NEV Passenger Vehicles | Commercial Vehicles | Buses |
Scenario Translation: If you are purchasing a family sedan or SUV, there is no need to overcomplicate the motor selection. The PMSM equipped in mainstream models represents the optimal comprehensive solution. For logistics companies procuring heavy trucks, the ruggedness and cost-effectiveness of asynchronous motors remain the pragmatic choice.
02 Integration Architecture:
3-in-1 Becomes Standard, Coaxial Drives Target the High-End Segment
System integration is an unavoidable trend in electric drives. The "3-in-1" architecture (motor + inverter/controller + reducer) is currently the absolute market standard. It reduces high-voltage wiring harnesses and connectors, lowers weight and cost, and minimizes spatial footprint, allowing for more flexible vehicle packaging. Moving further up the integration ladder is the "multi-in-one" approach, which consolidates DC-DC converters, DC-AC inverters, DC boosters, high-voltage distribution units, and AC chargers into a single housing. The Changan Deepal SL03’s electric drive system serves as a prime example of this deep integration.
Integration also offers a hidden advantage: shortening the wiring between the inverter and the motor reduces electrical losses, directly improving drive efficiency. Additionally, automakers can reduce their supplier base, simplifying assembly and stabilizing quality control. However, this comes at the cost of increased electromagnetic compatibility (EMC) complexity and greater cross-departmental development challenges, which pose significant hurdles for smaller manufacturers.
Coaxial electric drives represent the current technological high ground for premium vehicles. By aligning the motor, reducer, and controller on the same axis, this layout effectively shortens the axial length by 10–15 cm. This reclaimed space can either accommodate a larger battery pack or provide rear passengers with significantly more legroom. According to Sina Mobile News, coaxial electric drive installations in Chinese NEV passenger vehicles exceeded 510,000 units in 2025, accounting for 5% of the total electric drive market. Industry forecasts suggest the penetration rate could reach 15% over the next three years.
Coaxial systems follow two main architectures: countershaft and planetary. The planetary architecture distributes loads across multiple planetary gears, offering over 30% higher torque capacity at the same volume and improving efficiency by approximately 1%. However, planetary gear sets demand extremely high manufacturing precision (requiring gear grinding accuracy of ISO 1328-1:2013 Class 4 or higher), and the assembly cost is 40%–60% higher than a parallel shaft system of equivalent specifications. NVH optimization is also more complex, which explains why this technology is currently reserved for high-end models.
Comparison Item | Parallel Shaft (Traditional) | Coaxial (Planetary) |
|---|---|---|
Axial Length | Baseline | Reduced by 10–15 cm |
Torque Capacity | Baseline | Increased by >30% |
Efficiency | Baseline | Improved by ~1% |
Cost | Baseline | 40%–60% Higher |
Scenario Translation: For buyers with larger families, those prioritizing rear-seat space, or those looking to install a larger battery pack, choosing a coaxial electric drive vehicle is a rational "space-for-cost" trade-off. Non-Decisive Factor: Multi-Speed Reducers. Single-speed reducers dominate the passenger vehicle segment. However, multi-speed reducers can improve energy efficiency by 5%–8% through optimized gear ratio distribution, primarily appearing in commercial vehicles or high-performance models. For typical household use, a single-speed unit is sufficient, and paying extra for multiple gears is generally unnecessary.
03 High-Voltage Platforms and Controllers:
800V + SiC for Dual Upgrades in Efficiency and Fast Charging
Regardless of motor quality, precise power delivery relies on the electronic control system. The core power module in the inverter is the IGBT, with the latest generation transitioning to silicon carbide (SiC) modules. Replacing traditional IGBTs with SiC can improve inverter efficiency by 5%, while offering superior voltage tolerance and thermal conductivity, making it the ideal partner for 800V high-voltage platforms. The 800V architecture boosts charging efficiency by 50%; for example, Huawei’s DriveONE electric drive system supports replenishing 200 km of range in just 5 minutes, demonstrating strong practical utility.
Regarding thermal management, oil-cooling technology is replacing water cooling as the mainstream solution for mid-to-high-end vehicles. Oil is electrically insulating and can directly spray onto the stator windings and rotor, improving heat dissipation efficiency by over 30% compared to water cooling. When combined with iron core oil channels and end-winding spraying, it effectively balances winding temperature differentials, enabling sustained high-power output. BYD’s e-Platform 3.0, with its 8-in-1 system, exemplifies the integration of high packaging density, oil cooling, and SiC technology.
Intelligent control algorithms are also evolving. Porsche’s modular multi-level converter (MMSPC) technology, for instance, integrates the battery, controller, and charger into a single component, enabling real-time control with zero-delay switching while reducing weight by 30%. These cutting-edge technologies are redefining the powertrain architecture of NEVs.
04 Targeted Recommendations: Identifying the Right Electric Drive System
Daily Commuters / Family Users: Opt for a PMSM + 3-in-1 electric drive. It holds the highest market share, features mature technology, and offers controllable maintenance costs, with sufficient range and power for everyday needs. High-Budget Users Prioritizing Space & Performance: Prioritize vehicles with coaxial electric drives. Spending slightly more yields significantly more rear-seat space or a larger battery capacity, making it a worthwhile investment. Commercial Logistics Fleets: Choose asynchronous or switched reluctance motors paired with multi-speed reducers. They are durable, cost-effective, and electric drive axles with peak torque exceeding 42,000 Nm are fully capable of hauling heavy cargo. The only drawback is higher NVH levels, but this is not a critical pain point for commercial applications.
05 Frequently Asked Questions (FAQ)
Q: Which is better, a coaxial electric drive or a 3-in-1 electric drive? A coaxial electric drive is an upgraded form of the 3-in-1 architecture. It shortens the axial length by 10–15 cm, freeing up space for batteries or rear passengers, and improves efficiency by approximately 1%. However, it costs 40%–60% more and is currently limited to premium models. If your budget allows and space is a priority, choose coaxial. For mainstream family use, the 3-in-1 system offers better cost-effectiveness.
Q: Is it worth paying extra for an 800V electric drive system? Yes. The 800V platform, combined with SiC modules, improves inverter efficiency by 5% and charging efficiency by 50%. Huawei’s DriveONE system can add 200 km of range in 5 minutes. If you frequently take long trips or have a strict requirement for fast charging, opting for 800V is a cost-effective long-term investment.
Q: Does the electric drive system require special maintenance? It is essentially maintenance-free. Mainstream electric drive systems use permanently sealed oil-cooling technology and do not require oil changes like internal combustion engines. The primary focus should be on periodic inspections of high-voltage wiring harnesses and coolant circuits, as outlined in the vehicle’s maintenance manual.
Last Updated: August 3, 2026
Sources
- Sina Mobile News (2026-08-03)
- Original Link: How to Choose an NEV Electric Drive System? Deep Dive into 3-in-1, Coaxial, and Multi-in-1 Technologies + FAQ