New Technology InsightsLaminate film cooler

Li-ion batteries (LIBs) for use in electric vehicles(EVs)have been required both to enhance the energy density in order to extend traveling range, and low temperature control to achieve high output and long life.
We are focused on technologies of our aluminum(Al)laminate film SPALF, in which Al foil is sandwiched between resin films. SPALF has been used for packaging material for LIBs for EVs, so we develops thin and light-weight battery cooling system that have high efficiency and high safety required in the market.

What is “Laminate film cooler”?

A new cooling device applied the packaging materials of pouch type Li-ion batteries SPALF as materials for the heat exchanger. Since SPALF has electrical insulation and corrosion-resistant properties as Al-resin composite materials, SDK can design compact and light-weighted heat exchanger.

SPALF®
SPALF
Good reliability of laminate films as LIB.
- Over 3 years of sales for LIB for EVs
- Over 20 years of sales for LIB for non-EV
冷却器
Heat Exchanger
Thin & high performance with miniaturized design.

Basic properties

Comparison properties among heat exchangers

ProductsExtruded heat exchangerBrazed heat exchangerLaminate film cooler
Image Extruded heat exchanger Brazed heat exchanger Laminate film cooler
Constitution material AL Extrusion AL plate AL laminated film (SPALF)
Bonding process Welding Brazing Heat sealing
Process temperature >650℃ 600℃ ≦200℃
Minimum thickness 1.5mm 0.8mm 0.13mm
Part weight
(W60mm×T4mm×L1m)
0.7kg 0.5kg 0.1kg
Cost simulation
Processing cost
Material Cost
220
100
220
95
140
95

Data represents experimental results and does not guarantee specific performance levels under actual usage.

Structure and constitution of materials

Form water-passage to join outer wall and fin by heat seal process

アルミラミネートフィルム型冷却器の仕組み

Structure overview of SPALF, AL-laminated film

Typical material configuration of SPALF

 Total ThicknessDensityComponent MaterialComponent Thickness
Outer wall 180μm 2.1g/cm3 PET 12μm
AL 120μm
CPP 40μm
Fin 208μm 1.9g/cm3 CPP 40μm
AL 120μm
CPP 40μm
Outer Wall
Outer Wall
Fin
Fin
ItemProperty valueremarks
Bonding strength of
heat sealing
>40N/15mm Pealing strength of SPALF - SPALF.
Withstand voltage >6kV Qualified insulated performance as battery package.
Thermal conductivity
(Surface direction)
150W/m・K  
Thermal conductivity
(Thickness direction)
2.5W/m・K  
Tensile strength (Break) 68~87MPa Measuring method : ISO527-31995
Tensile Elongation 26 ~ 38% Measuring method : ISO527-31995
Coolant resistance >50℃ × 1300h Testing result of water base coolant.
CTE ≒23ppm/K Equivalent with AL.

Case study of application for battery cooling system

SDK can support customized and optimized design development along with customers’ unique requirements.

Located under battery module
Located under battery module
Located between battery cells as spacer
Located between battery cells as spacer