Hybrid Vehicle Battery Warm-Up Using Engine Coolant Heat Exchange

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In hybrid vehicles, abnormal temperature detection of the battery pack can lead to incorrect control of the bypass valve, resulting in a decrease in battery output due to inadequate warming using cooling water from the internal combustion engine.

Innovation Solution

The system initiates the internal combustion engine when the battery's State of Charge (SOC) reaches a predetermined level and the output falls below a threshold, then uses a control valve to facilitate heat exchange between the cooling water for the internal combustion engine and the battery, warming the battery and maintaining its output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bypass valve is controlled based on battery temperature sensor detection, then the battery can be warmed up by engine cooling water, but when temperature detection is abnormal, the bypass valve is incorrectly controlled and battery output deteriorates

Engineering Contradiction:

Improvebattery outputVSAvoidtemperature detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The control device continuously monitors battery temperature and adjusts the bypass valve opening degree based on real-time temperature feedback. When the battery temperature is below the target temperature, the bypass valve is opened to allow engine cooling water to flow through the battery cooling system, providing heat to warm up the battery. This closed-loop feedback control ensures reliable battery output by maintaining appropriate temperature regardless of detection abnormalities.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system pre-warms the battery using engine cooling water before the battery is needed for high-power output. By monitoring battery temperature in advance and activating the bypass valve when temperature is low, the system ensures the battery reaches optimal temperature before critical operations, cushioning against potential output deterioration.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the internal combustion engine is started to warm the battery, then battery output is maintained, but fuel consumption increases

Engineering Contradiction:

Improvebattery outputVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system uses the internal combustion engine's own cooling water, which is already being circulated for engine temperature management, to warm up the battery. The bypass valve redirects existing cooling water flow to pass through the battery cooling system, allowing the battery to utilize the thermal energy already present in the cooling circuit. This self-service approach maintains battery output without requiring additional fuel consumption for dedicated heating.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system converts the thermal energy in the engine cooling water, which would otherwise be wasted to the environment, into a useful resource for warming up the battery. By opening the bypass valve, the cooling water transfers its thermal energy to the battery, turning a potential waste stream into a beneficial heating source that maintains battery performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach effectively suppresses the deterioration of battery output due to temperature decreases, ensuring reliable EV travel by maintaining the battery's temperature and output within optimal ranges.

Implementation Method 1

heat exchange between a first refrigerant for cooling the internal combustion engine and a second refrigerant for cooling the battery is carried out

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the second refrigerant is warmed by the first refrigerant so as to warm up the battery

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20250033528A1Hybrid vehicle control method and hybrid vehicle control device

Publication Date: 2025.01.30 NISSAN MOTOR CO LTD

AI summary

In a hybrid vehicle, the warm-up of a battery (2) is controlled in consideration of the SOC of battery (2) and the temperature of battery (2). That is, in the hybrid vehicle, for example, when the SOC of battery (2) reaches a preset predetermined value and the output of battery (2) is lower than a first threshold value, a first control valve (8) is opened to perform the heat exchange between a first cooling water and a second cooling water by a heat exchanger (6). Consequently, in the hybrid vehicle, the second cooling water in a second cooling path (4) is warmed by the first cooling water in a first cooling path (3) to warm up battery (2), thereby suppressing a decrease in output of battery (2) due to a temperature decrease in battery (2).