EV Battery Unit Mounting Structure for Resonance Suppression

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Solution Overview

Problem

The challenge of reducing traveling noises in electric vehicles due to resonance between the battery unit and the vehicle body, while maintaining the mounting rigidity of the battery, is addressed by ensuring the battery module is firmly connected to the vehicle-body-side floor frames via side frames, with a module supporting mechanism that includes a combination of a pair of right and a pair of front-and-rear cross frames, and a pair of mounting brackets that allow for vertical movement of the battery module, thereby separating the vertical moves of the side frame and battery module to suppress resonance.

Innovation Solution

The battery unit is connected to the vehicle body via a pair of right-and-left side frames and a pair of front-and-rear module supporting mechanisms, comprising a pair of front-and-rear cross frames and mounting brackets, which allow for vertical movement of the battery module, thus separating its vertical move from the side frame's move, using a double vibration-proof mechanism to suppress resonance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the battery unit is firmly mounted to the vehicle body, then the mounting rigidity is improved, but resonance between the battery unit and vehicle body occurs, generating traveling noises

Engineering Contradiction:
Improvemounting rigidityVSAvoidtraveling noises
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The mounting structure is divided into multiple independent components: side frames, cross frames, and mounting brackets. This segmentation allows each component to have optimized rigidity characteristics, preventing overall resonance while maintaining local mounting strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the mounting structure have different rigidity characteristics. The side frames have high rigidity for stable mounting, while the cross frames and mounting brackets have lower rigidity to allow vibration isolation. This local differentiation of quality prevents resonance while maintaining necessary mounting stability.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If damping materials are added to suppress traveling noises, then the noise level is reduced, but the vehicle weight increases

Engineering Contradiction:
Improvetraveling noisesVSAvoidvehicle weight
Core Design Contradiction:
Object-generated harmful factorsVSWeight of moving object

Solution Approach 1:

The cross frames and mounting brackets act as intermediary vibration isolation components between the battery unit and vehicle body. These intermediaries absorb and isolate vibrations mechanically, replacing the need for additional damping materials that would increase weight.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mounting structure is designed with controlled flexibility in specific components (cross frames and mounting brackets) to dynamically respond to vibrations. This dynamic design allows the structure to adapt to vibration frequencies, isolating noise without requiring heavy damping materials.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the battery unit weight is increased to improve stability, then the mounting stability is improved, but the resonance frequency shifts, potentially worsening traveling noises

Engineering Contradiction:
Improvemounting stabilityVSAvoidtraveling noises
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The mounting system is segmented into stable support structures (side frames) and flexible isolation elements (cross frames and mounting brackets). This segmentation allows the battery unit's weight to provide stability through the rigid side frames, while the flexible intermediate components prevent resonance by decoupling the heavy battery from the vehicle body's vibration modes.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively reduces traveling noises by suppressing resonance between the battery unit and the vehicle body, achieving weight reduction and improved vibration characteristics without increasing the vehicle's weight.

Implementation Method 1

the bending rigidity, in the vertical direction, of the module supporting mechanism is lower than that of the side frame, so that the vertical move of the side frame and the vertical move of the battery module can be separated from each other, thereby the resonance, in the vertical direction, of the vehicle body and the battery unit can be suppressed

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3744547B1Electric vehicle, and use of battery unit
Publication Date: 2025.12.17 MAZDA MOTOR CORP
  • EP3744547B1 patent drawingFigure 1
  • EP3744547B1 patent drawingFigure 2
  • EP3744547B1 patent drawingFigure 3

AI summary

There are provided a floor panel 2, a pair of right-and-left floor frames 3, and a battery unit 10 supporting a battery module 11 and mounted at the floor frames 3. The battery unit 10 comprises the battery module 11, a pair of right-and-left side frames 21 mounted at the pair of floor frames 3, and a pair of front-and-rear module supporting mechanisms which comprises a pair of front-and-rear cross frames 33, 31 respectively extending in a vehicle width direction and interconnecting the pair of side frames 21 and mounting brackets 51, 52 supporting a front end portion and a rear end portion of the battery module 11. Bending rigidity, in a vertical direction, of the module supporting mechanism comprising the third cross frame 33 and the first mounting bracket 51 is set to be lower than that of the side frame 21.