Battery Cell Sleeve Cooling Using Capillary Liquid Channels

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Solution Overview

Problem

Battery cells in electrical storage systems generate heat, requiring cooling, but existing cooling methods often have insufficient heat extraction rates and complex designs that complicate manufacturing and service.

Innovation Solution

An energy storage system design featuring a base plate with cell holders, a top plate with sleeves, and capillary channels for liquid flow, allowing for improved heat extraction via capillary action, simplified structure, and controlled liquid/gas management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a cooling liquid is supplied to the battery cells, then heat extraction is achieved, but the heat extraction rate is insufficient

Engineering Contradiction:
Improveheat extraction rateVSAvoidcooling effectiveness
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent replaces the conventional mechanical pump-based liquid circulation system with a capillary action-based passive cooling system. The capillary channels formed between the battery cell and the cooling plate enable liquid flow without mechanical pumping, improving heat extraction efficiency while simplifying the system structure and eliminating pump-related reliability issues.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes capillary channels with specific dimensional characteristics (1-10 mm width) formed between the battery cell and cooling plate. These capillary structures enable passive liquid transport through surface tension and capillary pressure, enhancing heat extraction without requiring external energy input or mechanical components.

Inventive Principle:
Principle #31Porous materials

2Reliability

If conventional cooling systems are used, then cooling function is provided, but the design becomes overly complex

Engineering Contradiction:
Improvecooling functionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the cooling plate with the battery cell assembly structure, integrating the cooling function directly into the structural components. The cooling plate is positioned in direct thermal contact with the battery cell, and the capillary channels are formed in the interface between these components, eliminating the need for separate cooling circuits, pumps, and complex piping systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling system is designed to be self-regulating through capillary action. The liquid automatically flows through the capillary channels based on temperature-driven pressure differentials and surface tension forces, without requiring external control systems, sensors, or active management, thereby reducing system complexity while maintaining reliable cooling function.

Inventive Principle:
Principle #25Self-service

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

Enhances heat extraction efficiency, simplifies manufacturing, and reduces complexity by ensuring effective cooling and liquid/gas handling.

Implementation Method 1

a capillary channel is formed between the at least one battery cell and the at least one sleeve. The energy storage system is configured such that by supplying a liquid to the first volume, the liquid travels through the capillary channel via capillary action

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a cooling liquid may be supplied to the battery cells such that heat may be extracted from the battery cells

Methodology Applied
Scientific EffectHeat extraction: Conduction (thermal)

Data Source

PatentEP4645519A1An energy storage system comprising at least one battery cell
Publication Date: 2025.11.05 VOLVO TRUCK CORP
  • EP4645519A1 patent drawingFigure 1
  • EP4645519A1 patent drawingFigure 2a
  • EP4645519A1 patent drawingFigure 2b

AI summary

An energy storage system (4) comprising at least one battery cell (6) comprising a first end (8), a second end (10), and a central axis (c) extending therebetween. The energy storage system further comprises a base plate (12) comprising at least one cell holder (14). Each cell holder configured to hold the first end of one battery cell. The energy storage system further comprises a top plate (16), spaced from the base plate such that a first volume (18) is formed therebetween. The top plate comprising at least one sleeve (20). The energy storage system configured such that each sleeve extends along the central axis of one battery cell and is fluidly connected to the first volume, and wherein a capillary channel (22) is formed between each battery cell and each sleeve, the energy storage system being configured such that by supplying a liquid to the first volume, the liquid travels through each capillary channel via capillary action.