Battery Module Undercut Fastening for Crash Force Management

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Solution Overview

Problem

Existing fastening devices for battery modules in motor vehicles fail to provide a secure and reliable connection, especially during crashes, which can lead to safety hazards due to high acceleration forces and potential displacement of the battery into the passenger compartment.

Innovation Solution

A device featuring a support with undercuts that interact with corresponding undercuts on the bodyshell, distributing crash forces and preventing the battery module from being dislodged, while also simplifying assembly alignment and ensuring secure screw connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If only screw connections are used to fasten the battery module to the bodyshell, then the device structure is simple, but the connection reliability is insufficient under high crash forces

Engineering Contradiction:

Improveconnection reliabilityVSAvoidfastening device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The fastening connection is segmented into two distinct functional elements: screw connections for normal mounting and undercuts for crash force absorption. This segmentation allows each element to be optimized for its specific function, with undercuts providing form-fitting engagement to absorb crash forces and protect the screw connections from damage

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The undercut structure is designed as a pre-existing protective feature that absorbs crash forces before they can damage the screw connections. The form-fitting engagement of undercuts creates a cushioning effect that prevents direct transmission of high crash forces to the screw fastening points

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Strength

If the battery module is secured with multiple screw points, then the connection strength increases, but the forces on each screw point become excessive during crashes

Engineering Contradiction:

Improveconnection strengthVSAvoidforce on screw points

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

The force transmission path is segmented by introducing undercuts that engage separately from the screw connections. During normal operation, both screws and undercuts provide strength, but during crashes the undercuts bear the majority of impact forces, protecting the screw points from excessive loading

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If the battery module design is simplified, then manufacturing ease increases, but alignment precision during assembly deteriorates

Engineering Contradiction:

Improveassembly easeVSAvoidalignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The undercut structure provides self-aligning functionality during assembly. The form-fitting engagement of undercuts automatically guides the battery module into the correct position relative to the bodyshell, eliminating the need for complex external alignment fixtures or procedures

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9358864B2Device for fastening a battery module to a bodyshell of a motor vehicle

Publication Date: 2016.06.07 DR ING H C F PORSCHE AG

AI summary

A device is provided for fastening a battery module (2) to a bodyshell (1) of a motor vehicle. The battery module has a battery (15) and a support (16) connected fixedly to the battery. The support (16) has an undercut (22) that interacts with an undercut (11) on the bodyshell. Such a connection can be produced in a simple manner and, moreover, is reliably secure in the event of a crash, in particular a rear crash of the motor vehicle.