Battery Pack Cell Restraint for Vibration and Prismatic Growth

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Solution Overview

Problem

Battery packs face issues with cell motion relative to the housing due to vibrations and prismatic cell growth, leading to potential damage and reduced cell life, which affects operability, reliability, and longevity.

Innovation Solution

The battery pack incorporates spring plates between the cell array and the container to apply a spring force, restraining cell motion in the direction parallel to the row axis and accommodating cell growth, while restraining pins provide additional restraint in the orthogonal direction, ensuring consistent cell stack forces and maintaining a stable sidewall to enhance sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If spring force is applied to restrain cell motion, then cell stability improves, but sidewall dimensional stability may be compromised

Engineering Contradiction:
Improvecell stabilityVSAvoidsidewall dimensional stability
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The spring plate acts as an intermediary element between the cells and the rigid sidewall. It transmits the restraining force to the cells while absorbing deformations through its own elastic compliance, preventing direct transmission of cell growth forces to the sidewall and thus protecting sidewall dimensional stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple restraint mechanisms are added to control cell motion in multiple directions, then cell motion control improves, but device complexity increases

Engineering Contradiction:
Improvecell motion controlVSAvoidrestraint mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring plate performs multiple functions simultaneously: it restrains cell motion laterally, accommodates prismatic growth through deformation, and maintains consistent contact force. This multi-functionality reduces the need for separate restraint mechanisms for each function, thereby reducing overall complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 cell damage, maintains dimensional stability of the sidewall, improves sealing, and enhances the reliability and longevity of the battery pack by accommodating cell growth and restraining motion, thereby improving battery pack operability.

Implementation Method 1

a spring plate disposed at an end of the row of cells so as to reside between an outermost cell of the row and a corresponding sidewall of the container. The spring plate is free of attachment to the container or to the cells, and is configured to apply a spring force to the array.

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

The spring plate includes a first surface that faces the cells, an opposed second surface that faces the container sidewall, and a thickness corresponding to the distance between the first surface and the second surface. The first surface is non-planar and the thickness of the spring plate is uniform.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3688826B1Battery pack including cell restraint
Publication Date: 2024.12.11 ROBERT BOSCH GMBH
  • EP3688826B1 patent drawingFigure 1
  • EP3688826B1 patent drawingFigure 2
  • EP3688826B1 patent drawingFigure 3

AI summary

A battery pack(1) includes a housing(2) and an array of electrochemical cells(80) disposed in the housing(2). The housing(2) includes a container (3)and a lid (30)that closes an open end of the container(3). The container (3)has a base(4), a sidewall(8) that surrounds the base(4), and a spring plate(110) disposed inside the sidewall(8) between the cells(80) and the sidewall(8). The spring plate(110)is free standing within the container(3) and applies a spring force to the cell array that restrains the cells(80) along an axis normal to the surface of the spring plates(110). The lid(30)includes inwardly-protruding pins (50,60)that further restrain the cells(80) within the housing(2).