Battery Cooling Control During Thermal Runaway Shutdown

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Solution Overview

Problem

Existing methods for preventing thermal propagation in vehicle batteries are complex and inefficient, particularly during thermal runaway, as they rely on active cooling systems that shut down with the high-voltage system, allowing heat to spread and potentially ignite neighboring cells.

Innovation Solution

A control device activates a coolant pump using a low-voltage system to circulate coolant and distribute heat away from thermal runaway cells, utilizing the existing thermal capacity of the cooling system and other components to absorb and dissipate heat, even when the high-voltage system is deactivated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If active cooling is used to cool the battery during normal operation, then cooling efficiency is improved, but in the event of thermal runaway the high-voltage system shuts down and active cooling becomes unavailable

Engineering Contradiction:

Improvebattery temperatureVSAvoidcooling availability during thermal runaway

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The cooling system is segmented into two independent power supply paths: high-voltage power supply for normal active cooling operation, and low-voltage power supply for emergency cooling operation during thermal runaway. This segmentation ensures that cooling functionality is not completely lost when the high-voltage system shuts down.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control device is configured to detect thermal runaway conditions and activate the low-voltage coolant pump in advance before thermal propagation occurs. This preliminary action ensures that cooling is maintained during the critical transition period when the high-voltage system shuts down but before neighboring cells ignite.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If thermally insulating cell intermediate materials are used to block heat conduction paths, then thermal propagation prevention is improved, but the complexity of the battery structure increases

Engineering Contradiction:

Improvethermal propagationVSAvoidbattery structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The coolant acts as an intermediary heat transfer medium that absorbs heat from the battery cells and transports it away from the battery pack. This intermediary approach provides thermal management without requiring complex insulating structures between cells, as the flowing coolant dynamically manages heat distribution.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling system utilizes the battery's own cooling infrastructure (coolant channels and pump) to prevent thermal propagation, rather than adding separate insulating components. The existing cooling system is repurposed for safety functions, eliminating the need for additional structural complexity.

Inventive Principle:

Principle #25Self-service

3Use of energy by moving object

If the coolant pump is deactivated during thermal runaway to save energy, then energy consumption is reduced, but heat dissipation capability is lost

Engineering Contradiction:

Improveenergy consumptionVSAvoidheat dissipation capability

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The system changes the operating parameters of the cooling system during thermal runaway: switching from high-voltage/high-power cooling to low-voltage/continuous cooling. The coolant flow rate and pump power are adjusted to match the reduced thermal load while maintaining sufficient heat dissipation to prevent thermal propagation.

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

This method effectively reduces heat transfer to neighboring cells, preventing or delaying thermal runaway by using the existing cooling system to absorb and distribute heat, ensuring safety and preventing battery ignition.

Implementation Method 1

the coolant can flow as part of at least one cooling circuit through which the coolant can flow

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

circulates the coolant present in at least one cooling circuit

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

utilizing the existing thermal capacity of the cooling system and other components to absorb and dissipate heat

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentUS12548819B2Method for cooling a battery of a motor vehicle, cooling arrangement, and motor vehicle

Publication Date: 2026.02.10 AUDI AG

AI summary

A method for cooling a battery of a motor vehicle, which includes multiple battery cells, by a cooling device through which a coolant can flow, as part of at least one cooling circuit through which the coolant can flow, which includes at least one coolant pump, which in an active state circulates the coolant present in at least one cooling circuit in the cooling circuit. In particular, a control device controls at least one coolant pump depending on a detection of a faul state which is connected to a thermal runaway of at least one of the battery cells of the battery, such that the at least one coolant pump is activated or continues to be operated in the active state when the faul state is detected.