E-Mobility

Battery Heating

Direct heating for HV traction batteries — ultra-thin PTC foils up to 350 kW/m² for rapid warm-up and pre-conditioning. 15+ years of expertise.

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Challenge

Li-ion battery performance deteriorates significantly at low temperatures: reduced electrochemical reaction rate, accelerated health degradation, and lithium plating risk. Battery thermal management systems (BTMS) must enable rapid warm-up while being ultra-thin, lightweight, and safe. Conventional solutions add significant package space and weight. With growing battery capacities and the demand for fast charging in cold climates, the requirement for efficient, safe battery heating has become a critical factor in EV competitiveness.

Our Solution

ATT offers direct battery heating via ultra-thin PTC foils placed between cells or on cooling plates (up to 350 kW/m² in boost mode, 50 V, 40 W per foil). The PTC self-regulation at a defined temperature (e.g. 45°C) eliminates thermal runaway risk without requiring external temperature sensors or control electronics. As area heaters, our foils achieve uniform temperature distribution with minimal package space — ideal for space-constrained battery architectures.

How It Works

Thermal System Analysis

Joint analysis of your battery architecture, cell chemistry and thermal targets. We determine the optimal heating solution for your pack design — whether cell wall, cell bottom or cooling plate integration.

Solution Design & Simulation

Custom heater layout designed using proprietary thermal simulation tools. Foil geometry matched to cell dimensions, power distribution optimised for uniform temperature.

Prototyping & Validation

Functional prototypes manufactured in-house for thermal performance testing. Validation includes temperature uniformity, heat-up rate, power consumption and integration fit in your module or pack.

Qualification & Series

Full automotive qualification per OEM requirements. PTC foils are designed, developed and manufactured in-house — ensuring full lifecycle support from pre-development to series production.

PTC Foil Heating

Cell wall heating: ultra-thin foil between cells, ideal for pouch cells (165 × 125 mm, customizable)
Cell bottom heating: rigid or flexible foil on cooling plate with integrated temp sensor
Self-regulating PTC — no risk of thermal runaway, no external temp control needed
Up to 350 kW/m² in boost mode, virtually no impact on cooling system effectiveness

Application Areas

Pouch Cell Modules

Ultra-thin PTC foils (165 × 125 mm standard, customizable) placed between pouch cells for direct cell wall heating. Virtually no additional package height — critical in space-constrained modules.

Prismatic Cell Packs

Rigid or flexible PTC foils mounted on cooling plates below prismatic cells. Integrated temperature sensor enables cell-level monitoring while the PTC effect ensures inherent safety.

Fast Charging Pre-Conditioning

Rapid battery warm-up before DC fast charging in cold conditions. Direct PTC foils deliver up to 350 kW/m² in boost mode for minimal pre-conditioning time, maximizing charging throughput.

Technical Data

Heating Power Density Up to 350 kW/m²

Cell Wall Heater Voltage 50 V (NV/HV, AC/DC)

Cell Wall Heater Power 40 W per foil

PTC Self-Regulation e.g. 45°C

Heating Circuits 2 (optimized distribution)

Key Advantages

15+ years of battery thermal engineering experience
Single source: development, design and manufacturing all in-house
PTC self-regulation: inherent safety without additional sensors or electronics
Full lifecycle support: pre-development through series production

Frequently Asked Questions

How does PTC self-regulation prevent thermal runaway?

PTC (Positive Temperature Coefficient) materials increase their electrical resistance as temperature rises. At the defined regulation temperature (e.g. 45°C), power output drops to near zero — the heater physically cannot exceed this temperature. No external temperature sensors, control circuits or safety cutoffs are required. This inherent self-limiting behavior makes PTC heating the safest option for battery applications.

What cell formats are compatible with ATT direct heating foils?

Standard cell wall foils measure 165 × 125 mm, designed for common pouch cell dimensions. However, geometry, size and power density are fully customizable. Foils can be engineered for prismatic and cylindrical cell formats, as well as cooling plate integration. Contact us with your cell and module specifications.

What voltage range do ATT battery heating solutions support?

PTC foils operate at 50 V, compatible with NV/HV and AC/DC configurations. The solutions are designed for the voltage and safety requirements of modern EV traction battery systems.

How does ATT support battery heating projects from concept to series?

ATT provides full lifecycle support: initial thermal analysis, solution concept, prototype manufacturing, validation testing, and series production — all from in-house capabilities. With 15+ years of battery thermal engineering experience, we understand not just the heating element but the entire thermal management system context.

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