Inverter Reactive Current Battery Self-Heating

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Solution Overview

Problem

Existing methods for heating vehicle batteries in cold climates, such as using external heat sources or charging processes, are inefficient due to high energy expenditure and limitations in electric vehicles without an additional power source.

Innovation Solution

A DC to AC inverter circuit with a controller that generates a heating mode AC current with a reactive AC component and no DC current component, allowing the battery to self-heat internally by selectively controlling the inverter switches to produce high frequency harmonics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If external heat sources (heated jacket or block heater) are used to warm the battery, then the battery temperature increases, but the energy expenditure is relatively high compared to the small increase in internal temperature

Engineering Contradiction:

Improvebattery temperatureVSAvoidenergy expenditure

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The battery warms itself by utilizing its own stored electrical energy converted to heat through resistive heating elements integrated into the battery structure, eliminating the need for external power sources and reducing overall energy expenditure

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical/external heating systems with an electrical heating system that uses the battery's own electrical energy, converting electrical energy directly to thermal energy through resistance heating within the battery cells

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If the battery charging process is used to warm the battery in hybrid-electric vehicles, then the battery is warmed internally through current flow, but this approach does not work with electric vehicles due to the absence of an additional power source

Engineering Contradiction:

Improvebattery temperatureVSAvoidapplicability to different vehicle types

Core Design Contradiction:

TemperatureVSAdaptability or versatility

Solution Approach 1:

The heating system is designed to function in both hybrid-electric vehicles (using regenerative braking energy) and electric vehicles (using stored battery energy), making the solution universally applicable across different vehicle architectures

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The battery uses its own stored energy to generate heat, eliminating the need for external power sources or additional power sources, thereby enabling the system to work in both HEVs and EVs

Inventive Principle:

Principle #25Self-service

3Temperature

If traditional heating methods are used, then the battery can be warmed, but idle periods in the battery current profile are wasted and preheating time is extended

Engineering Contradiction:

Improvebattery temperatureVSAvoidpreheating time

Core Design Contradiction:

TemperatureVSLoss of time

Solution Approach 1:

The heating system operates continuously during idle periods by converting what would be wasted current into useful heat, eliminating idle time and reducing overall preheating duration through continuous effective action

Inventive Principle:

Principle #20Continuity of useful action

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 solution enables efficient internal battery heating in electric vehicles, reducing energy expenditure and eliminating idle periods in the battery current profile, thus achieving faster preheating without the need for external power sources or center taps.

Implementation Method 1

the heating mode AC current will cause the battery to internally self-heat

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS7382102B2Heating of batteries using reactive power

Publication Date: 2008.06.03 FCA US LLC

AI summary

A circuit and method are provided for allowing self-heating of a battery used to power an AC motor by way of connection to a DC to AC inverter circuit. The inverter is selectively controlled to generate a heating mode AC current at the DC side connection to the battery, wherein the heating mode AC current is formed substantially of only a reactive AC current component and substantially no DC current component. In accordance with another aspect, the heating mode AC current is generated to fill the idle time in the operation of the battery.