Battery Pack Compensation Element for Solid-State Cell Swelling

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Solution Overview

Problem

Existing battery packs for electric and hybrid road vehicles face challenges in managing the thickness variation of solid-state electrolyte cells, requiring high maximum force values that lead to bulky and heavy compensation elements, compromising energy density and weight optimization.

Innovation Solution

The battery pack incorporates a modular structure with compensation elements that elastically and plastically deform to maintain contact between the solid-state electrolyte and electrodes, reducing the force required and minimizing the weight and size of the compensation elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rigid compensation elements are used to maintain contact with cells during thickness increase, then the solid-state electrolyte remains in contact with electrodes, but the compensation elements become bulky and heavy

Engineering Contradiction:

Improvecontact maintenance between solid-state electrolyte and electrodesVSAvoidweight of compensation elements

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The compensation element transitions from a rigid structure to a flexible membrane that can elastically deform. This parameter change in material properties allows the membrane to adapt to cell thickness variations without requiring excessive force or bulky dimensions, thereby reducing weight while maintaining reliable contact.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention employs a flexible membrane instead of rigid compensation elements. This thin film structure can conformally contact the cell surface and maintain electrical contact through elastic deformation, significantly reducing the mass and volume of the compensation structure compared to rigid alternatives.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If high maximum force values are applied to compensate for thickness variation, then contact is maintained, but the compensation elements become bulky and heavy

Engineering Contradiction:

Improvecontact pressure maintenanceVSAvoidvolume of compensation elements

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The membrane is designed to dynamically adapt its shape and contact pressure in response to cell thickness changes during operation. This dynamic behavior allows the system to maintain optimal contact without requiring oversized compensation elements, reducing overall volume.

Inventive Principle:

Principle #15Dynamics

3Force

If stiff compensation elements are used to obtain required pressure, then contact force is sufficient, but tolerances of individual cell components cannot be compensated

Engineering Contradiction:

Improvepressure on cellsVSAvoidtolerance compensation

Core Design Contradiction:

ForceVSAdaptability or versatility

Solution Approach 1:

The flexible membrane can conformally adapt to slight variations in cell dimensions and surface topology, providing uniform pressure distribution across the cell surface. This flexibility enables the system to accommodate manufacturing tolerances while maintaining sufficient contact force.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The membrane provides locally adapted pressure distribution, with each region of the membrane independently deforming to match the local cell surface geometry. This local adaptation capability ensures adequate contact pressure across the entire cell surface despite variations in cell component tolerances.

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

This solution effectively reduces the force exerted on the cells, minimizing the weight and size of the compensation elements, thereby enhancing energy density and reducing the overall weight and dimensions of the battery pack.

Implementation Method 1

compensation elements that elastically and plastically deform to maintain contact between the solid-state electrolyte and electrodes

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

compensation elements that elastically and plastically deform to maintain contact between the solid-state electrolyte and electrodes

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS20250125401A1Battery pack for an electric road vehicle and method for the compensation of the thickness variation of an electrochemical cell for said battery pack

Publication Date: 2025.04.17 FERRARI SPA

AI summary

A battery pack for an electric road vehicle includes a first electrochemical cell comprising a cathode, an anode and a solid electrolyte electrically connected thereto. The first cell has a first thickness along a direction increasing following the activation of the first cell. A first compensation element cooperates with the first cell along the direction and is subjected to a compression force, which is variable along the direction between a minimum value and a maximum value. The compensation element has a second thickness along the direction, which is variable between a maximum value and a minimum value. The first compensation element plastically deforms itself when it is subjected to a predetermined value of the compression force, which is greater than or equal the minimum value and is smaller than the maximum value, so as to plastically reduce the second thickness for values of the force exceeding the predetermined value.