Battery Self-Heating Control Using Temperature and State of Charge

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Solution Overview

Problem

Electric vehicle batteries experience performance degradation and safety issues in low-temperature environments, leading to inefficient charging and reduced service life, particularly due to reduced electrochemical reaction activity and lithium ion precipitation.

Innovation Solution

A battery self-heating method that involves obtaining the battery's temperature and state of charge, determining current amplitude and frequency for self-heating, and performing closed-loop control on a battery self-heating device to optimize heating efficiency using impedance characteristics at different frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If battery heating is performed in low-temperature environments, then battery performance and charging speed are improved, but power consumption increases and heating efficiency is reduced due to impedance characteristics

Engineering Contradiction:
Improvecharging speedVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamic adjustment of heating current parameters (amplitude and frequency) based on real-time battery temperature and state of charge. The control system dynamically modifies the AC component amplitude and frequency of the heating current to adapt to changing battery impedance characteristics, thereby optimizing heating efficiency and reducing power consumption while maintaining charging speed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters of heating current (amplitude and frequency) according to battery temperature and state of charge. By adjusting the AC component amplitude and frequency based on battery impedance characteristics at different states, the system optimizes heating efficiency and reduces power consumption while maintaining effective charging speed.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If heating current is applied to battery in low-temperature environments, then battery temperature is increased, but heating uniformity is poor and power consumption is high

Engineering Contradiction:
Improvebattery temperatureVSAvoidheating uniformity
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent employs periodic AC current components superimposed on the DC heating current. The AC component with adjustable frequency and amplitude creates periodic heating effects that promote more uniform heat distribution throughout the battery, reducing temperature gradients and improving heating uniformity while controlling overall power consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control system dynamically adjusts the AC component parameters (amplitude and frequency) based on real-time battery temperature feedback and state of charge. This dynamic adjustment ensures uniform heating by adapting the periodic action intensity to the battery's thermal state, preventing localized overheating while maintaining overall heating efficiency.

Inventive Principle:
Principle #15Dynamics

3Productivity

If conventional heating control is used, then heating process is simple, but heating efficiency is low and battery life is reduced

Engineering Contradiction:
Improveheating efficiencyVSAvoidcontrol complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a closed-loop feedback control system that continuously monitors battery temperature and state of charge, and uses this information to adjust the heating current parameters. The control unit modifies the AC component amplitude and frequency based on feedback from temperature sensors and battery state measurements, thereby optimizing heating efficiency and protecting battery life through adaptive control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system changes the amplitude and frequency parameters of the heating current based on battery temperature and state of charge feedback. By dynamically adjusting these parameters according to battery impedance characteristics at different states, the system achieves high heating efficiency while extending battery life through optimized thermal management.

Inventive Principle:
Principle #35Parameter changes

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

Improves battery self-heating efficiency and reduces power consumption by applying current excitation based on temperature and state of charge, ensuring uniform heating and extending battery life.

Implementation Method 1

performing a closed-loop control on a battery self-heating device according to the current amplitude and the frequency, so as to self-heat the battery

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4368444A1Battery self-heating method, and vehicle
Publication Date: 2024.05.15 XIAOMI EV TECH CO LTD
  • EP4368444A1 patent drawingFigure 1
  • EP4368444A1 patent drawingFigure 2
  • EP4368444A1 patent drawingFigure 3~5

AI summary

A battery self-heating method includes: obtaining (S 101) a temperature and a state of charge of a battery; determining (S 102) a current amplitude and a frequency during self-heating of the battery according to the temperature and the state of charge; and performing (S103) a closed-loop control on a battery self-heating device according to the current amplitude and the frequency, so as to self-heat the battery.