Summary of Key Points
Recently, new energy vehicles (NEVs) have become increasingly heavier. Many models have a curb weight (weight without passengers and cargo) exceeding 3 tons, which is even heavier than that of light trucks from a decade ago. The reasons include the high weight of batteries (low energy density), the addition of two energy systems in plug-in hybrid/extended range vehicles, market demand for larger vehicles with advanced features, and the increasing use of intelligent technologies. Although automakers are calling for weight reduction, engineering challenges, cost pressures, and market demands are making vehicles heavier. In the future, systemic technological innovations will be needed, and policies are beginning to restrict heavier vehicles. Therefore, lightweighting has become a critical issue for automakers' survival.
Detailed Explanation
1. Why are NEVs heavier than fuel-powered cars? Batteries are the "primary culprit"
NEVs should be lighter because they lack engines and transmissions. However, the reality is the opposite: the fuel-powered version of the BYD Tang weighs 1.89 tons, while the electric version weighs 2.45 tons (an increase of 560 kilograms); the fuel-powered BMW X3 weighs 1.85 tons, whereas the electric iX3 weighs 2.80 tons (an increase of 350 kilograms). The core issue is the energy density difference: gasoline can store 12 kilowatt-hours per kilogram, while lithium-ion batteries can only store 0.2-0.3 kilowatt-hours per kilogram (a difference of 40-60 times). To travel 500 kilometers, a fuel-powered car requires only about 30 kilograms of gasoline, whereas an electric vehicle's battery needs 300-400 kilograms.
2. The heavier the vehicle, the more weight is required to compensate
An increase in vehicle weight triggers a vicious cycle:
- Larger batteries → heavier vehicles → higher energy consumption → larger batteries needed → even heavier vehicles;
- Heavier vehicles require stronger motors, suspensions, and brakes (otherwise, they won't stop effectively), which further increases the weight;
- To improve noise and vibration insulation (NVH), more insulation materials are added; to optimize performance, various additional components are installed, leading to a continuous increase in weight.
For example, NIO's new models use 900V high-voltage technology to reduce the weight of wiring harnesses, but this requires changes to the entire electronic architecture. Simply replacing individual wires is not enough; systemic improvements are necessary.
3. Automakers want to reduce weight but find it difficult
Automakers want to reduce weight, but they face three major obstacles:
- Engineering challenges: Reducing weight at specific points (such as by using aluminum alloy components) is easy, but systemic weight reduction (e.g., integrating multiple systems into a single powertrain) requires cross-departmental and cross-supplier collaboration, increasing development risks;
- Cost considerations: Lightweight materials (like carbon fiber) are expensive, and companies need to balance cost and weight reduction benefits;
- Market factors: Larger vehicles generate higher profits (for example, flagship SUVs earn more than smaller cars). Consumers prefer larger spaces and more advanced features, and there are no additional taxes on heavier vehicles in some markets, so automakers naturally prefer to produce larger models.
4. Types of weight increases: necessary vs. unnecessary
Not all weight increases are undesirable. It's important to distinguish between:
- Necessary weight increases: For safety (high-strength steel required by crash standards, battery protection systems) and reliability (thermal management systems), which are essential for passenger safety;
- Unnecessary weight increases:
- Extra components added for marketing purposes (e.g., rarely used features);
- Subsequent additions due to poor initial design (e.g., thick walls with weak structures).
For instance, the Lotus Elise sports car does not include a refrigerator because it adds weight and goes against the principle of lightweighting.
5. The way forward: technological innovation + policy constraints
To address the issue of heavy vehicles, a combination of technology and policy is needed:
- Technological solutions:
- Integrated powertrains: Combining motors and electronic controls to reduce weight by up to 20%;
- Semi-solid-state batteries: Higher energy density, resulting in lighter batteries for the same range (expected to be mass-produced by 2026-2027);
- Axial flux motors: These motors are 30-50% lighter than traditional ones;
- Integrated casting: Used in the Tesla Model Y, which reduced the vehicle weight by 30%.
- Policy measures:
- Paris imposes triple parking fees on heavier vehicles (1.6 tons for fuel-powered cars, 2 tons for electric vehicles);
- The EU requires battery carbon footprint reporting (larger batteries emit more carbon);
- Regulations on the total vehicle weight are approaching the limits of 3.5 tons in Europe and 4.5 tons in China; policies may be adjusted accordingly.
These changes will force automakers to prioritize lightweighting. After all, heavier vehicles may face both compliance costs and market rejection in the future.
Final Conclusion
The increasing weight of NEVs is a result of physical limitations, market demands, and engineering compromises. However, with technological advancements and stricter policies, lightweighting will become a necessity rather than an option. This is crucial for automakers to overcome current challenges and thrive in the industry.
(End of article)