EV Battery Module Mounting Rigidity for Road Noise Suppression

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing battery mounting structures in electric vehicles face challenges in reducing traveling noises while maintaining compactness, as the resonance of battery modules with the vehicle-body vibration can amplify noise in the middle-frequency band, particularly affecting road-noise performance.

Innovation Solution

The battery unit is designed with a configuration of right-and-left side frames and cross frames, where battery modules are arranged in multiple rows with varying mounting rigidity, including different mounting brackets to differentiate natural frequencies, thereby suppressing resonance and vehicle-body vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If battery modules are arranged in multiple rows at the same position with uniform mounting, then the battery unit achieves compactness, but the modules resonate with vehicle-body vibration at middle-frequency band (100-400Hz) deteriorating road-noise performance

Engineering Contradiction:
Improvebattery unit arrangement spaceVSAvoidroad noise
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by differentiating the mounting rigidity of battery modules based on their position. Specifically, battery modules in odd-numbered rows are mounted with different rigidity compared to those in even-numbered rows. This creates local variations in mounting characteristics across the uniform battery module array, causing each row to have distinct natural frequencies that avoid resonance with vehicle-body vibration in the middle-frequency band, thereby reducing road noise while maintaining compact arrangement.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If battery modules are mounted with uniform rigidity to simplify structure, then manufacturing is easier, but all modules resonate together amplifying vehicle-body vibration

Engineering Contradiction:
Improvemounting structure simplicityVSAvoidvibration resonance
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies segmentation by dividing the battery modules into distinct groups based on their row positions. Battery modules in odd-numbered rows are segmented from those in even-numbered rows, with each group having different mounting rigidity characteristics. This segmentation prevents uniform resonance across all modules while maintaining relatively simple mounting structures within each group, thus reducing vibration amplification without overly complicating manufacturing.

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 resonance and noise levels by varying the mounting rigidity of battery modules, enhancing the compactness and noise suppression performance of the battery unit.

Implementation Method 1

since each of the battery modules has substantially the same natural frequency, all of these battery modules so resonate with vehicle-body vibration at a specified frequency band that the vehicle-body vibration may be improperly amplified

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

Vibration energy caused by a wheel running on a road surface is transmitted to a vehicle-body strength member through a suspension member and then vibrates a panel member

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3744621B1Electric vehicle and use of battery unit
Publication Date: 2026.05.06 MAZDA MOTOR CORP
  • EP3744621B1 patent drawingFigure 1
  • EP3744621B1 patent drawingFigure 2
  • EP3744621B1 patent drawingFigure 3

AI summary

A battery unit 10 comprises side frames 21, cross frames 31 - 33, and plural battery modules 11 having substantially the same size comprising a longitudinal dimension, a lateral dimension, and a height dimension. The battery modules 11 are respectively mounted at the cross frames 31 - 33 in the same position and arranged in plural rows adjacently to a vehicle width direction such that a direction of the above-described longitudinal dimension is substantially parallel to a vehicle longitudinal direction, and mounting rigidity of the battery modules 11 stored in a first storage area S1 is set to be different from that of the battery modules 11 stored in second and third storage areas S2, S3.