Battery Module Fluid Cushion Support for Cell Expansion Durability

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Solution Overview

Problem

The existing battery systems with fluid pressure adjusting means suffer from reduced energy density and durability issues due to fluid springs' susceptibility to damage from repeated charging/discharging, which affects endplates and tab leads.

Innovation Solution

A battery module design incorporating a battery cell stack with plate-shaped endplates, fluid cushions, and holders that support regions not facing the cells, along with integrated positioners and concave side surfaces, to manage expansion and prevent damage, while using stretchable materials for fluid cushions and rigid holders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluid pressure adjusting means are used to control fluid springs, then the battery system can maintain proper pressure and support, but the energy density is reduced due to the additional components

Engineering Contradiction:

Improvepressure control reliabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent removes the fluid pressure adjusting means from the system, extracting the problematic component that reduced energy density. The fluid springs are designed to function autonomously without external pressure adjustment mechanisms, thereby eliminating the trade-off between pressure control reliability and energy density.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The fluid springs are designed to self-regulate their function without requiring external control systems. The holders provide fixed support points that allow the fluid springs to autonomously maintain proper pressure and support during battery cell expansion and contraction, eliminating the need for energy-consuming pressure adjustment mechanisms.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If fluid springs are used to accommodate battery cell expansion, then the battery module can handle charging-induced expansion, but the fluid springs and endplates become susceptible to damage from repeated charging/discharging

Engineering Contradiction:

Improveexpansion accommodationVSAvoiddurability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the support function by introducing holders that provide fixed support points for the fluid springs. This segmentation prevents the fluid springs from bearing the full mechanical stress of repeated expansion and contraction, distributing the load and reducing damage susceptibility while maintaining expansion accommodation capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The holders are positioned beforehand to provide pre-established support points for the fluid springs. This prior cushioning arrangement ensures that during repeated charging and discharging cycles, the fluid springs have predetermined support structures that prevent excessive deformation and reduce the risk of damage to both the fluid springs and endplates.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If holders are added to support fluid cushions, then durability is improved by preventing damage, but the device complexity increases

Engineering Contradiction:

ImprovedurabilityVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The holders are designed to perform multiple functions simultaneously: they provide fixed support points for fluid springs, maintain proper spacing between battery cells, and contribute to the overall structural integrity of the battery module. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving improved durability.

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

The design suppresses energy density reduction and enhances durability by controlling fluid cushion expansion, protecting tab leads and endplates from damage, and ensuring smooth operation under varying charge states.

Implementation Method 1

the fluid pressure in the fluid springs increases when the fluid springs contract in the stacking direction of the battery cells and expand in a direction perpendicular to the stacking direction of the battery cells in response to the expansion of the battery cells that is associated with the charging

Methodology Applied

Scientific EffectFluid expansion and contraction: Thermal Expansion

Implementation Method 2

holders that support regions of the fluid cushions, the regions not facing the battery cells

Methodology Applied

Scientific EffectMechanical support and constraint: Mechanical Force

Data Source

PatentUS20250226504A1Battery module and method for manufacturing battery module

Publication Date: 2025.07.10 HONDA MOTOR CO LTD

AI summary

Provided is a battery module including: a battery cell stack that has a plurality of battery cells stacked atop one another; a pair of plate-shaped members that are provided on the two ends of the battery cell stack in the stacking direction; fluid cushions that are disposed between the plurality of battery cells; and holders that support regions of the fluid cushions, the regions not facing the battery cells.