Split EV Battery Underbody Layout for Propeller Shaft Clearance

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Solution Overview

Problem

Existing high voltage battery units for electric vehicles pose challenges when installed under the center floor of a vehicle, as they occupy space needed for a propeller shaft, limiting power transmission to the rear wheel and requiring a separate motor for all-wheel drive, which restricts motor size and power performance.

Innovation Solution

A battery unit design with a lower case featuring two battery compartments and a connecting portion bent convex upwardly, incorporating a reinforcing structure and power wire configuration that allows the propeller shaft to pass through, thereby securing space for power transmission while preventing damage to high voltage wires during collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the high voltage battery unit is mounted under the center floor of the vehicle, then the utilization of the trunk or the luggage space is maximized, but it is difficult to secure a space for disposing a propeller shaft for transmitting power from the power train to the rear wheel

Engineering Contradiction:

Improveluggage spaceVSAvoidspace for propeller shaft

Core Design Contradiction:

Area of stationary objectVSVolume of moving object

Solution Approach 1:

The battery case is divided into two separate battery compartments (first and second battery compartments) positioned on opposite sides of the vehicle. This segmentation creates a central space between the compartments where the propeller shaft can be disposed, allowing both maximum luggage space utilization and adequate space for power transmission components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The battery compartments are arranged in a lateral direction (left and right sides of the vehicle) rather than occupying the entire under-floor space. This dimensional reorganization frees up the central vertical space needed for the propeller shaft while maintaining compact battery placement.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the high voltage battery unit is mounted under the center floor of the vehicle, then it is possible to maximize the utilization of the trunk or the luggage space, but a separate motor must be mounted for driving the rear wheel to implement all-wheel drive operation

Engineering Contradiction:

Improveluggage spaceVSAvoidmotor configuration

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

By dividing the battery case into two compartments positioned laterally, the design creates central space that accommodates the propeller shaft, enabling all-wheel drive through mechanical power transmission rather than requiring separate electric motors for each wheel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent enables mechanical power transmission (propeller shaft system) to replace the need for separate electric motors, combining mechanical and electrical systems to achieve all-wheel drive capability with simpler architecture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If the battery unit is installed under the center floor outside the vehicle, then it is possible to maximize luggage space, but it is not possible to increase the size of the motor for driving the rear wheel due to limited installation space

Engineering Contradiction:

Improveluggage spaceVSAvoidmotor power performance

Core Design Contradiction:

Area of stationary objectVSPower

Solution Approach 1:

The lateral segmentation of battery compartments creates unused central space that can accommodate larger power transmission components, eliminating the space constraint that would otherwise limit motor or propeller shaft sizing for all-wheel drive operation.

Inventive Principle:

Principle #1Segmentation

4Volume of moving object

If a connecting portion is bent convex upwardly between battery compartments, then space is secured for the propeller shaft, but the high voltage wires may be damaged during collisions

Engineering Contradiction:

Improvespace for propeller shaftVSAvoidwire protection

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

A reinforcing structure is pre-installed on the connecting portion before the battery unit is installed in the vehicle. This preliminary reinforcement protects the high voltage wires from collision damage while maintaining the convex upward shape needed for propeller shaft accommodation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reinforcing structure acts as a protective barrier that absorbs or deflects collision forces before they can reach the high voltage wires, providing beforehand cushioning that prevents wire damage during side collisions or impacts.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS12280653B2Battery unit for vehicle and underbody of vehicle including the same

Publication Date: 2025.04.22 KIA CORPORATION

AI summary

A battery unit for a vehicle is provided. The battery unit includes a lower case having two battery compartments arranged in a direction toward opposite sides of the vehicle, respectively, and a connecting portion bent to be convex upwardly between the two battery compartments. A reinforcing structure is disposed on the connecting portion. Two battery modules are installed in the two battery compartments, respectively and a power wire is electrically connected to at least one of the two battery modules and extends from one of the two battery compartments to the other one of the two battery compartments through the connecting portion.