Lightweighting for NEVs: Safety Cannot Be Compromised — How This Bumper Beam Achieves 9% Weight Reduction While Withstanding 37kN Impact Load

Currently, as new energy vehicles universally pursue extended driving range, the accompanying increase in battery capacity has significantly added to overall vehicle weight. With curb weights frequently exceeding two tons, this not only leads to higher energy consumption but also impairs handling dynamics and places greater loads on tire and suspension systems. Under complex road conditions, it may even amplify risks such as vehicle instability or rollover tendencies.

Achieving vehicle weight reduction while guaranteeing body structural strength and crash safety has become an unavoidable challenge in the R&D of new energy vehicles, as well as a key contributor to product competitiveness. Today, we will take a crash beam as an example to illustrate how new energy vehicles can reduce weight while maintaining rigorous safety thresholds.

Today we'll use a bumper beam as an example to see how NEVs achieve lightweighting without crossing safety red lines.

1. High-Strength & High-Toughness Aluminum Alloy KS370
KS370 is a high-strength and high-toughness 6xxx series aluminum alloy independently developed by Xinbo Alloy Materials Research Institute. It is mainly applied to structural components such as new energy vehicle bumper beams, as well as battery tray side rails of commercial vehicles and heavy trucks. During the development project of a certain type of bumper beam, we adopted the widely used 6082-T6 aluminum alloy for automotive structural parts as the control reference.

All test data are measured and issued by an independent third-party laboratory based on customer-specified customized products.

A：Yield strength increased by approximately 17.9%
Yield strength determines the critical point where a material transitions from elastic deformation to irreversible plastic deformation. The increment from 280 MPa to 330 MPa indicates that under identical cross-section and loading conditions, KS370 can sustain higher loads before substantial plastic deformation takes place. On the other hand, this surplus performance capacity can be utilized to optimize wall thickness and cross-sectional profiles, cutting down material usage.
This enhancement in mechanical performance constitutes the core material foundation for weight reduction of the bumper beam.

B：Tensile strength increased by approximately 12.9%
Tensile strength reflects the maximum stress a material can withstand during tension. 
Rising from 310 MPa to 350 MPa represents a further upgrade in the ultimate load-bearing capacity of the material. It helps delay material failure under complex stress states during a crash. However, this 12.9% strength improvement cannot be directly interpreted as a 12.9% enhancement in overall vehicle safety. The crash performance of the complete vehicle is also governed by cross-sectional design, joining methods, deformation path in crumple zone‌ and auto body structure.

C: Elongation increased from 10% to 12%
Generally speaking, the plasticity of a material tends to decrease when its strength is improved. For KS370, elongation is raised from 10% to 12% alongside the strength upgrade, which demonstrates that the material maintains superior plasticity even under large deformation.
For bumper beams, this property means the material not only possesses high load-bearing capacity but also enables sustained progressive deformation under loading. This reduces the risk of premature cracking or sudden fracture.

2. Why can KS370, a stronger material, also be lighter?
Both KS370 and 6082 are aluminum alloys, and the density difference between them is not the primary source of weight reduction in this project. 

The true logic of weight reduction is as follows: improved material strength → enables optimization of cross-section and wall thickness → reduces material usage → lowers component weight.

In this project, the bumper beam was reduced from 6.088 kg to 5.538 kg, a decrease of 0.55 kg, representing a weight reduction of approximately 9.03%.

Notably, the elongation of KS370 did not decline despite the increase in strength, preserving sufficient plasticity to accommodate significant deformation during collision events. This demonstrates not a simplistic "substituting strength for weight" approach, but rather a strategy that enhances strength while retaining plasticity, and then leverages the improved material properties to achieve structural lightweighting.

3. How does the weight-reduced bumper beam perform?
The KS370 bumper beam was subjected to quasi-static three-point bending tests. Under conditions of a 254 mm diameter indenter and an 880 mm span, the specimen achieved a loading displacement of 220 mm without exhibiting any penetrating cracks. The maximum load reached 37.224 kN—significantly exceeding the typical OEM requirement of ≥25 kN for current 6082 bumper beams.

In dynamic bending tests, the samples once again showed no signs of penetrating cracks, with the peak acceleration reaching 22.6158 g.

These tests verify that the weight-reduced specimens still deliver excellent load-bearing capacity and structural integrity under large deformation.

4. What does a weight reduction of 0.55 kg mean?
It is important to maintain an objective perspective: each bumper beam achieves a weight reduction of 0.55 kg. For a nearly 2-ton new energy vehicle, this accounts for only approximately 0.03% of the total vehicle weight. Relying solely on this single beam can hardly bring about perceptible changes in overall vehicle weight or energy consumption.

Yet the value brought by this 0.55 kg cut cannot be measured merely by the number.

★ Value 1 | Validating a Feasible Weight Reduction Solution 
KS370 proves that high-toughness 6xxx series aluminum alloys allow optimized cross-sectional profiles and wall thicknesses for safety structural parts.

★ Value 2 | Accumulated Incremental Effect through Gradual Weight 
Reduction When this alloy is extended to front/rear bumper beams, battery tray side beams, sill beams and other load-bearing parts, the summed weight savings will collectively bring tangible improvements to NEV energy efficiency, cruising range and vehicle handling.

★ Value 3 | Lightweight Design and Safety Are Not Mutually Exclusive
The true value lies not merely in the 0.55 kg weight reduction, but in the fact that the bumper beam retains its load-bearing capacity and deformation performance under existing test conditions even after approximately 9% weight cut.

Core Conclusion
The value of KS370 does not lie in directly converting the 0.55 kg weight reduction of a single bumper beam into extended driving range. Instead, it validates a replicable lightweighting methodology: relying on elevated strength and elongation to unlock weight-reduction potential for safety-critical structural components, and verifying the load-bearing and deformation performance of lightweighted parts through component-level tests.

This also represents the core R&D focus of Xinbo Alloy Materials Research Institute in its long-term in-depth research on high-strength and high-toughness aluminum alloys: Let lightweighting stand every challenge.

5. New materials create new possibilities for lightweighting.
Through this one bumper beam, KS370 offers a glimpse into a single dimension of what it takes to lightweight a modern EV—but the full picture is far larger.

Different vehicle models, components, and operating conditions impose varying requirements on material strength, toughness, formability, and joining performance. Currently, KS400, developed to meet higher-performance requirements, has completed R&D and pilot test and is about to enter mass production. Xinbo Alloy Materials Research Institute is expanding the KS-series material system to more structural applications, including sill beams, battery trays and subframes.

Cross-sectional views of various conventional bumper beam structures

Truly viable lightweighting must start from the application scenario, advancing material R&D, structural design, and manufacturing processes in parallel. The ultimate value of a material must be validated in real products.

Lightweighting does not mean pursuing the lowest possible weight, but retaining sufficient strength, toughness and safety margins while achieving weight reduction.

About Xinbo Alloy Materials Research Institute
Chuzhou Xinbo Alloy Materials Research Institute (Xinbo Research Institute) is an innovative R&D institution jointly established by Xinbo Aluminum Co., Ltd. (003038.SZ), Tianchang Tianchuang Technology Industry Development Co., Ltd., and relevant participants in the alloy material industrial chain. It focuses on the R&D and application of high-performance alloy materials such as aluminum and magnesium. Maintaining open cooperation with vehicle manufacturers, auto parts suppliers, universities and industrial partners, the institute provides customized R&D of high-performance aluminum alloys, material replacement and lightweighting solutions, material testing, prototype trial production, and component performance verification services.

If your team is exploring alloy material upgrades, lightweight structural design, or component-level validation, we invite you to get in touch. Together, we can uncover new solutions and push the boundaries of what's achievable.