EV Battery Pack Crash Structure for Front Collision Energy Absorption

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Solution Overview

Problem

Designing a collision energy absorbing system for electric vehicles with heavy battery packs poses challenges in safety, production complexity, and cost efficiency, as existing solutions do not adequately address the unique safety demands and weight distribution of electric vehicle battery packs.

Innovation Solution

A collision energy absorbing system is implemented, featuring a first absorbing structure positioned between the battery pack and the vehicle's front, which absorbs most of the collision energy during a head-on collision, thereby reducing the load on the vehicle body frame structure, allowing for a simpler and lighter frame design. This system includes deformation sections and rigid parts that distribute energy and prevent battery pack damage, with the battery pack being releasably attached to the frame to decouple during severe collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the battery pack is arranged in the bottom of the vehicle below the floor of the passenger compartment, then the centre of gravity of the vehicle is lowered, but the collision energy absorption design becomes more complex and the battery pack is vulnerable to puncture damage

Engineering Contradiction:
Improvecentre of gravity positionVSAvoidbody frame structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The body frame structure is segmented into a first body frame part and a second body frame part, with the battery pack positioned between them. This segmentation allows the first part to specifically handle collision energy absorption while the second part provides structural support, simplifying the overall design by dividing functions into separate components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A deformable member is introduced as an intermediary element between the battery pack and the rigid members of the body frame. This deformable member absorbs collision energy through controlled deformation, protecting the battery pack from direct impact forces while maintaining the structural integrity of the overall frame.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If a heavy battery pack is installed to extend the driving distance, then the vehicle's electric energy storage capacity is improved, but the collision energy that must be absorbed by the vehicle structure increases

Engineering Contradiction:
Improveelectric energy storage capacityVSAvoidcollision energy
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The collision energy absorption function is segmented from the main body frame structure and assigned to a dedicated first body frame part. This part is specifically designed with deformable members that absorb collision energy, allowing the rest of the body frame to focus on structural support without being overloaded by collision forces from the heavy battery pack.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the body frame are given different mechanical properties: the first body frame part contains deformable members with controlled deformation characteristics for energy absorption, while the second body frame part maintains high rigidity for structural support. This local differentiation of material properties optimizes both collision energy absorption and structural integrity.

Inventive Principle:
Principle #3Local quality

3Reliability

If the body frame structure is designed to handle the collision energy of the battery pack, then the safety is improved, but the weight of the body frame structure increases

Engineering Contradiction:
Improvecollision safetyVSAvoidbody frame structure weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The body frame is divided into functional segments where only the first body frame part is designed for collision energy absorption using deformable members. The second body frame part uses rigid members for structural support without the added weight of energy absorption features, reducing the overall frame weight while maintaining safety through localized energy management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A deformable member acts as an intermediary between the battery pack and the rigid body frame structure. This intermediary absorbs collision energy through controlled deformation, protecting the rigid frame from direct impact forces and allowing the frame to be designed with less weight while maintaining equivalent safety performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If rigid members are used throughout the body frame structure, then the structural strength is improved, but the collision energy from the battery pack cannot be absorbed effectively

Engineering Contradiction:
Improvebody frame structural strengthVSAvoidcollision energy absorption
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The body frame is segmented into a first part with deformable members for energy absorption and a second part with rigid members for structural strength. This segmentation allows each segment to perform its optimized function: the deformable part absorbs collision energy through controlled deformation while the rigid part maintains overall structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The body frame exhibits local quality variations where the first body frame part has deformable characteristics for energy absorption while the second body frame part has rigid characteristics for structural support. This local differentiation allows the structure to both absorb collision energy effectively and maintain the necessary structural strength.

Inventive Principle:
Principle #3Local quality

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

The solution enhances safety by isolating the battery pack's collision energy from the vehicle frame, simplifies production by reducing frame complexity and weight, and allows for the reuse of existing vehicle platforms, reducing production costs and enabling easier adaptation to future battery advancements.

Implementation Method 1

a deformable member arranged between the battery pack and the at least one rigid member, wherein the deformable member is configured to, in case the vehicle is subject to a head-on collision with an object, deform elastically upon exposure to a collision force in a longitudinal direction of the vehicle

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the first absorbing structure may extend in a substantially longitudinal direction of the vehicle between the battery pack and a front of the vehicle and may contain one or several deformation sections/parts configured to absorb collision energy while deforming (buckling, bending, crumpling etc.)

Methodology Applied
Scientific EffectInelastic deformation: Deformation

Data Source

PatentEP3444138B1vehicle
Publication Date: 2024.12.11 POLESTAR PERFORMANCE
  • EP3444138B1 patent drawingFigure 1
  • EP3444138B1 patent drawingFigure 2a
  • EP3444138B1 patent drawingFigure 2b

AI summary

The invention concerns a vehicle (1) comprising: at least one electric motor configured for driving the vehicle (1); a battery pack (2, 2') configured to supply the electric motor with electric power for driving the vehicle (1); a vehicle body frame structure (3, 4, 5) configured to form a main supporting structure of the vehicle (1); and a collision energy absorbing system (6, 7, 8, 9, 10, 11, 12, 13) configured to absorb collision energy in the event of an accident. The invention is characterized in that the collision energy absorbing system comprises a first absorbing structure (6, 7, 8, 11, 12, 13) that is positioned between the battery pack (2, 2') and a front (1 a) of the vehicle (1), wherein the first absorbing structure (6, 7, 8, 11, 12, 13) is configured to, in case the vehicle (1) is subject to a head-on collision with an object, act against said object and absorb all or most of a collision energy of the battery pack (2, 2') without transferring said battery pack collision energy to the vehicle body frame structure (3, 4, 5).