Ripple Current Battery Heating Control

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Solution Overview

Problem

Existing secondary battery temperature control technologies are inefficient in quickly increasing battery temperature, especially in cold climates, and do not ensure optimal temperature control.

Innovation Solution

A secondary battery temperature-increasing control apparatus that uses a ripple generating device to actively cause a ripple current to flow in the battery, with a controller determining the optimal frequency and duration of the ripple current based on the battery's state of charge and temperature, ensuring the allowable output power is maintained or increased.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If discharge controller performs control so that an output electric current greater than the requested electric current flows to heat the battery, then the battery temperature increases quickly, but the allowable output power of the battery is reduced and the state of the secondary battery is degraded

Engineering Contradiction:
Improvebattery temperatureVSAvoidstate of the secondary battery
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention applies periodic action by using a ripple generating device to cause a ripple current (periodic current fluctuation) to flow in the secondary battery. This periodic current causes internal heat generation through the battery's internal resistance, efficiently increasing battery temperature without requiring excessive discharge current that would degrade battery state. The controller determines optimal ripple current parameters based on battery temperature and SOC to achieve effective heating while maintaining battery reliability.

Inventive Principle:
Principle #19Periodic action

2Speed

If discharge controller increases the output electric current to heat the battery quickly, then the temperature increase speed improves, but the efficiency in increasing the temperature is not optimized and the state of charge decreases excessively

Engineering Contradiction:
Improvetemperature increase speedVSAvoidstate of charge
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The invention converts the harmful effect of internal resistance (which normally causes energy loss and heat generation as a byproduct) into a beneficial heating mechanism. By deliberately inducing ripple current through the internal resistance, the system efficiently generates heat within the battery to increase temperature. The controller optimizes the ripple current parameters to achieve effective temperature increase while minimizing excessive SOC depletion, thus converting what is normally an energy loss into a useful heating function.

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

3Temperature

If no determination is made before performing temperature increase operation, then the temperature can be increased, but the allowable output power may be reduced and the temperature increase may not be optimal

Engineering Contradiction:
Improvebattery temperatureVSAvoidallowable output power
Core Design Contradiction:
TemperatureVSPower

Solution Approach 1:

The invention applies preliminary action by having the controller determine whether to perform the temperature increase operation before actually executing it. The controller calculates the allowable output power both before and after the temperature increase operation, and only proceeds with the ripple current heating when the post-operation allowable output power is equal to or greater than the pre-operation value. This preliminary determination ensures that temperature increase does not compromise the battery's power delivery capability.

Inventive Principle:
Principle #10Preliminary 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

Efficiently increases the temperature of the secondary battery using internal resistance heat generation, optimizing the temperature increase operation to prevent reduction in allowable output power.

Implementation Method 1

the temperature of the battery is increased by actively causing a ripple current to flow in the battery

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2451674B1Secondary battery temperature-increasing control apparatus, vehicle including the same, and secondary battery temperature-increasing control method
Publication Date: 2013.08.21 TOYOTA JIDOSHA KK
  • EP2451674B1 patent drawingFigure 1~2
  • EP2451674B1 patent drawingFigure 3~4
  • EP2451674B1 patent drawingFigure 5~6

AI summary

Λ first calculating section (118) calculates an allowable output power (WoutA) of the secondary battery before a ripple temperature increase operation for increasing the temperature of a secondary battery by causing a ripple current to flow in the secondary battery is performed, the allowable output power being determined in advance based on the temperature and a state of charge (SOC) of the secondary battery. A second calculating section (120) calculates the allowable output power (WoutB) achieved when the ripple temperature increase operation is performed. A determining section (122) determines whether to perform the ripple temperature increase operation so that when the allowable output power (WoutB) is equal to or greater than the allowable output power (WoutA), the ripple temperature increase operation is performed and, when the allowable output power (WoutB) is smaller than the allowable output power (WoutA), the ripple temperature increase operation is not performed.