Battery Spring Plate Tensioning for Dynamic Cell Compression

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Solution Overview

Problem

Existing battery designs face challenges in maintaining a consistent compressive force on battery cells as their state of charge changes, particularly in pouch battery cells with lithium chemistry, which can lead to inefficiencies and potential issues like lithium plating/dendrites and uneven compression distribution.

Innovation Solution

A battery design incorporating a spring plate with adjustable tension and varying radius of curvature, made of carbon fibers, that applies a compressive force through a top plate, allowing for easy assembly and maintaining a dynamic compression force throughout charging and discharging cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a rigid compression plate is used to apply force to battery cells, then assembly space is reduced, but the compression force cannot adapt to cell expansion/contraction during charging cycles

Engineering Contradiction:
Improvecompressive forceVSAvoidadaptability to cell size changes
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The spring plate is designed with dynamic properties, allowing it to flex and change its radius of curvature in response to battery cell expansion and contraction during charging cycles. This enables the compression force to adapt automatically without manual intervention or rigid structural constraints.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring plate's radius of curvature is configured to vary within a specific range (e.g., 50mm to 150mm) as the battery cells change size during operation. This parameter change allows the plate to maintain optimal contact and compression force across different cell states of charge.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the spring plate tension is fixed during assembly, then assembly is simplified, but the compression force becomes uneven as cells change state of charge

Engineering Contradiction:
Improveassembly simplicityVSAvoidcompression force consistency
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The spring plate is pre-configured with specific geometric parameters (radius of curvature, thickness, material properties) during manufacturing that enable it to automatically provide consistent compression force throughout the battery's operational cycles, eliminating the need for complex adjustment mechanisms during assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring plate serves itself by using its elastic properties to automatically adjust and maintain consistent compression force as battery cells expand and contract, without requiring external control systems or manual adjustments during operation.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If a flat rigid plate is used for compression, then manufacturing is simpler, but lithium plating/dendrites may occur due to insufficient compression adaptation

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidprevention of lithium plating/dendrites
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The spring plate's flexible, curved design allows it to dynamically adapt to battery cell volume changes during charging cycles, maintaining consistent compression force that prevents lithium plating and dendrite formation while keeping the manufacturing process relatively simple.

Inventive Principle:
Principle #15Dynamics

4Strength

If the spring plate radius of curvature is kept constant, then structural integrity is maintained, but compression force becomes uneven as cells shrink and expand

Engineering Contradiction:
Improvestructural integrityVSAvoidcompression force uniformity
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The spring plate is designed with a controlled variable radius of curvature that changes within a defined range as the battery cells expand and contract. This parameter variation maintains both structural integrity and uniform compression force distribution across different states of charge.

Inventive Principle:
Principle #35Parameter changes

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 design ensures a consistent and adjustable compressive force, preventing lithium plating/dendrites and promoting healthy aging of battery cells by adapting to changes in cell size, thereby enhancing battery performance and longevity.

Implementation Method 1

a spring plate providing a biasing force against the plurality of battery cells... the spring plate may provide a compressive force throughout a charging and discharging cycle as the battery cells shrink and expand

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The spring plate may include carbon fibers

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Data Source

PatentEP4421931A1Battery and battery with spring plate
Publication Date: 2024.08.28 SAFT AMERICA INC
  • EP4421931A1 patent drawingFigure 1
  • EP4421931A1 patent drawingFigure 2
  • EP4421931A1 patent drawingFigure 3~4

AI summary

A battery including a housing, a plurality of battery cells in the housing, and a spring plate providing a biasing force against the plurality of battery cells. The spring plate is configured such that a tension of the spring plate may be adjusted from outside of the housing.