EV Heat Pump Thermal Control for Extreme Cold Cabin Heating

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Solution Overview

Problem

Conventional electric vehicle thermal management systems are inefficient and complex, with limited capabilities for heating and cooling, especially in extreme cold conditions, and rely on high-voltage cabin heaters that reduce battery range and increase costs.

Innovation Solution

A vehicle thermal management system incorporating a vehicle heat pump with a compressor, cabin condenser, cabin evaporator, and chiller, along with control electronics that adjust the compressor and cabin blower to operate in efficient or lossy modes based on ambient, battery, and cabin temperatures, utilizing heat from the battery and drive train to assist in cabin heating, and allowing the heat pump to operate in various configurations to optimize heating and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional high-voltage cabin heaters are used for heating, then heating capability is achieved, but battery range is reduced and system cost increases

Engineering Contradiction:

Improvecabin heating capabilityVSAvoidbattery range

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent combines the cabin heating function with waste heat recovery from the battery thermal management system. The battery coolant loop, which normally only cools the battery, is modified to also serve as a heat source for cabin heating through a heat exchanger, merging two separate thermal management functions into one integrated system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent converts the waste heat generated by the battery during operation, which would otherwise be discarded to the environment, into a useful resource for cabin heating. By capturing this waste heat through a heat exchanger in the battery coolant loop, the system transforms a harmful thermal byproduct into a beneficial heating source, reducing the need for high-voltage cabin heaters.

Inventive Principle:

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

2Temperature

If conventional heat pump systems are used, then cooling capability is achieved, but heating capacity is insufficient in extremely cold conditions

Engineering Contradiction:

Improvecabin heating capacity in cold conditionsVSAvoidheating performance in extreme cold

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The system performs preliminary heating of the battery pack using waste heat from the drive train or ambient air before cold weather driving conditions begin. This pre-conditioning of the battery thermal management system ensures that waste heat is available when needed for cabin heating, even in extremely cold conditions where conventional heat pumps struggle.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The battery thermal management system is designed to perform multiple functions: cooling the battery during normal operation, heating the battery during cold conditions, and providing waste heat for cabin heating. This multi-functional approach allows the system to maintain reliable heating performance across a wide range of ambient temperatures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple independent thermal management subsystems are used, then specific thermal control functions are achieved, but system complexity increases

Engineering Contradiction:

Improvethermal control capabilityVSAvoidnumber of subsystems

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the cabin heating subsystem and battery thermal management subsystem into a single integrated system. By using the battery coolant loop to provide both battery cooling and cabin heating through a heat exchanger, the system eliminates the need for separate high-voltage cabin heaters and reduces the overall number of thermal management components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

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 system reduces the need for high-voltage cabin heaters, enhances cabin heating efficiency in low ambient temperatures, and improves overall vehicle efficiency by utilizing stored heat from the battery and drive train, while maintaining battery performance and extending vehicle range.

Implementation Method 1

a compressor, a cabin condenser, a cabin evaporator

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

a cabin condenser, a cabin evaporator

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

a cabin condenser, a cabin evaporator

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 4

a chiller. The battery system coolant loop is in thermal communication with a battery system

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentUS11807067B2Optimal source electric vehicle heat pump with extreme temperature heating capability and efficient thermal preconditioning

Publication Date: 2023.11.07 TESLA INC

AI summary

A vehicle thermal management system includes a vehicle heat pump system, a battery system coolant loop, a drive train coolant loop, and control electronics. The vehicle heat pump system includes a compressor, a cabin condenser, a cabin evaporator, a cabin blower, and a chiller. The battery system coolant loop is in thermal communication with a battery system and with the chiller and selectively in thermal communication with the drive train coolant loop. The control electronics control the components of the vehicle thermal management system to heat the cabin, cool the cabin, heat the battery system, cool the battery system, and cool the drive train. The control electronics may control the compressor to operate in an efficient mode or a lossy mode in which the compressor generates heat. The control electronics may also control the components of the vehicle thermal management system to precondition the battery.