Hybrid EV Battery Cooling Control During Thermal Runaway

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Solution Overview

Problem

Existing methods for managing thermal runaway in hybrid electric vehicle batteries involve disabling the high voltage to prevent further thermal runaway, which is a conservative approach that does not address the underlying issue of cooling the battery effectively, potentially leading to severe safety risks.

Innovation Solution

Utilizing the engine as a power source to drive a power generator, which supplies power to the cooling system to cool down the thermal runaway battery, thereby preventing the spread of thermal runaway and reducing safety hazards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the high voltage of the vehicle is disabled directly after thermal runaway to prevent further thermal runaway, then the risk of electrical abuse and thermal runaway deterioration is reduced, but the ability to cool down the battery is lost and thermal runaway may propagate to adjacent battery cores

Engineering Contradiction:
Improvesafety of battery systemVSAvoidthermal runaway propagation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent dynamically adjusts the high voltage disable strategy based on real-time battery temperature monitoring. Instead of immediately disabling high voltage upon detecting thermal runaway, the system continues to supply power to the cooling system as long as temperatures remain below a threshold, enabling adaptive response that balances safety with cooling effectiveness

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary cooling system that acts as a buffer between the thermal runaway event and the battery cores. By maintaining cooling system operation through alternative power sources (engine or kinetic energy recovery), the system creates a protective thermal barrier that prevents heat propagation while still allowing electrical systems to be disabled

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the cooling system is maintained operational to cool down the thermal runaway battery core, then thermal runaway propagation is suppressed, but additional power is required which may not be available when the traction battery is disabled

Engineering Contradiction:
Improvethermal runaway propagationVSAvoidpower consumption for cooling
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent implements self-service by utilizing the vehicle's own engine or kinetic energy recovery systems to generate power for the cooling system. The engine, which is already running to power the vehicle, can directly drive the cooling system, and kinetic energy during braking is recovered and used to sustain cooling operations without requiring external power sources

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the power source parameter from exclusively traction battery to multiple alternative sources including engine direct drive and kinetic energy recovery. This parameter change enables the cooling system to operate under different power availability conditions, transforming the energy supply approach to match the thermal management needs

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If the engine is controlled to drive the power generator to generate power for the cooling system, then the cooling system can operate continuously to cool the battery, but the engine operation may increase vehicle complexity and control difficulty

Engineering Contradiction:
Improvecooling system operation durationVSAvoidpower transmission system
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent makes the engine multi-functional by enabling it to serve both as the primary propulsion power source and as an auxiliary power source for the cooling system. The engine can directly drive the cooling system or drive a generator to produce electrical power for cooling, eliminating the need for dedicated cooling system motors or separate power transmission paths

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 method effectively cools the thermal runaway battery, reducing the risk of fire and explosion, and enhances vehicle safety by maintaining the cooling system operation even when the traction battery is disabled.

Implementation Method 1

a cooling system is controlled to cool down the thermal runaway battery

Methodology Applied
Scientific EffectHeat removal: Cooling

Implementation Method 2

an engine is controlled to drive a power generator to generate power

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

thermal runaway may occur sequentially in adjacent battery cores due to impact of a high temperature and smoke of the runaway battery core

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

thermal runaway may occur sequentially in adjacent battery cores due to impact of a high temperature and smoke of the runaway battery core

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP4596293A1Method for controlling hybrid electric vehicle, controller, medium, and vehicle
Publication Date: 2025.08.06 BYD CO LTD
  • EP4596293A1 patent drawingFigure 1~2
  • EP4596293A1 patent drawingFigure 3~5
  • EP4596293A1 patent drawing

AI summary

The present disclosure discloses a method for controlling a hybrid electric vehicle, a controller, a medium, and a vehicle. The method includes: A power generator is controlled to supply power to a cooling system when a thermal runaway state occurs in a traction battery of the vehicle, to cause the cooling system to cool down the traction battery. In view of the above, in the present disclosure, in the thermal runaway state, an engine is started to supply power to the entire vehicle. This can achieve rapid cooling of the traction battery in an emergency situation.