EV Battery Charger Preheating via High-Frequency Switching

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Solution Overview

Problem

Electric vehicle batteries perform poorly in cold temperatures, as existing charging systems do not effectively address the reduction in battery performance and efficiency during charging and discharging in cold ambient environments.

Innovation Solution

A method utilizing a battery charger to generate heat without charging the battery, by actuating switches at high frequencies and transferring this heat to the battery through conductive or convective means, ensuring the battery reaches an optimal temperature before charging, thereby improving performance in cold conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a battery charger is used to generate heat without charging the battery, then the battery temperature increases to improve performance in cold environments, but the charging process is delayed or prevented

Engineering Contradiction:
Improvebattery temperatureVSAvoidcharging speed
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The system performs preliminary heating of the battery before initiating the charging process. The battery charger operates in a heating mode that generates heat through resistive heating of internal components without transferring significant electric power to the battery, thereby preparing the battery at an optimal temperature for subsequent charging operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system employs periodic switching of the battery charger operates by repeatedly actuating switches at high frequencies (50 kHz to 1 MHz). This periodic action generates heat through resistive heating while preventing sustained charging current flow, allowing temperature increase without significant energy transfer to the battery.

Inventive Principle:
Principle #19Periodic action

2Temperature

If a dedicated battery heater is added to the system, then battery heating capability is improved, but system complexity and cost increase

Engineering Contradiction:
Improvebattery heating capabilityVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The battery charger is designed to perform multiple functions: normal charging operation and battery heating. By utilizing the existing charger circuitry for both purposes, the system eliminates the need for a separate dedicated heater, thereby reducing overall system complexity and cost while maintaining effective battery heating capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The battery charger serves itself by generating heat through its own internal resistive heating during operation. The charger's internal components act as heating elements, and the system uses its own operational modes to provide the heating function without requiring external or additional heating devices.

Inventive Principle:
Principle #25Self-service

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 enhances battery performance and efficiency in cold temperatures by preheating the battery before charging, potentially eliminating the need for a dedicated battery heater and improving overall system efficiency and cost-effectiveness.

Implementation Method 1

using the battery charger to generate heat without charging the battery with the battery charger may include repeatedly actuating a switch of the battery charger to generate heat

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

using a thermal fluid to transfer the heat generated using the battery charger to the battery to heat the battery

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The method may comprise transferring the heat generated using the battery charger to the battery by conductive heat transfer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4140802A1Battery charging system and method for electric vehicle
Publication Date: 2023.03.01 TAIGA MOTORS INC
  • EP4140802A1 patent drawingFigure 1
  • EP4140802A1 patent drawingFigure 2
  • EP4140802A1 patent drawingFigure 3

AI summary

Systems and methods for charging a battery of an electric vehicle are provided. One method includes heating a battery of the electric vehicle using a battery charger of the electric vehicle. The method includes using the battery charger to generate heat without charging the battery with the battery charger, and transferring the heat generated using the battery charger to the battery to heat the battery. Once a temperature of the battery is sufficiently high to accept a charge, the battery charger may be used to charge the battery.