Electric Vehicle Battery Heating Circuit Isolation Switch

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Solution Overview

Problem

The existing electric vehicle running control systems face issues where the heating circuit interferes with the load capacitor, causing voltage fluctuations and preventing the heating circuit from functioning normally, especially in low temperature environments.

Innovation Solution

The system incorporates a switchgear and switch control module that disconnects the in-vehicle battery from the load capacitor when the heating circuit is active, allowing the heating circuit and load capacitor to operate independently, using a bidirectional switchgear and heating circuit control module to manage energy flow and polarity reversal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the heating circuit and load capacitor work simultaneously to provide heating and power supply, then the battery can maintain temperature and supply power, but the voltage fluctuates violently and the heating circuit cannot work normally

Engineering Contradiction:
Improvedual function of heating and power supplyVSAvoidheating circuit normal operation
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the circuit into two independent operational modes using switch control: (1) heating mode where the heating circuit connects to the battery while the load capacitor disconnects, and (2) power supply mode where the load capacitor connects to the battery while the heating circuit disconnects. This segmentation eliminates the interference between heating and power supply functions that caused voltage fluctuations, while maintaining both functions through time-division multiplexing.

Inventive Principle:
Principle #1Segmentation

2Temperature

If the heating circuit is connected to the in-vehicle battery to heat the battery in low temperature, then the charging and discharging performance is improved, but the voltage fluctuates and the heating circuit may not work normally due to load capacitor interference

Engineering Contradiction:
Improvebattery temperatureVSAvoidheating circuit stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses a control module to detect battery temperature in advance and switch the circuit to heating mode before the battery temperature becomes critically low. The control module monitors battery parameters and proactively activates the heating circuit while disconnecting the load capacitor, preventing voltage fluctuations from occurring in the first place rather than reacting after problems arise.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the switchgear is controlled to disconnect the heating circuit from the load capacitor during heating, then the voltage stability is improved, but the circuit complexity increases

Engineering Contradiction:
Improvevoltage stabilityVSAvoidcircuit structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent employs a bidirectional switchgear that can operate in multiple modes: connecting the heating circuit to the battery, connecting the load capacitor to the battery, or disconnecting both. This universal switch component consolidates what would otherwise require multiple separate switches, reducing overall circuit complexity while achieving the necessary isolation between heating and power supply functions for voltage stability.

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

This configuration prevents interference between the heating circuit and load capacitor, ensuring stable voltage and efficient battery heating, thereby prolonging battery life and maintaining performance in low temperature conditions.

Implementation Method 1

By controlling an energy to flow between the in-vehicle battery E and the heating circuit F so as to heat a damping element in the heating circuit F, the in-vehicle battery E is heated

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2804780B1Electric vehicle running control system
Publication Date: 2017.12.20 SHENZHEN BYD AUTO R&D
  • EP2804780B1 patent drawingFigure 1~2
  • EP2804780B1 patent drawingFigure 3~5
  • EP2804780B1 patent drawingFigure 6~7

AI summary

An electric vehicle running control system is provided. The electric vehicle running control system comprises: a heating circuit (11); a load capacitor (C12); a switchgear (20) connected with the heating circuit (11) and the load capacitor (C12) respectively; and a switch control module (200) connected with the switchgear (20) for controlling the switchgear (20) to switch off when the heating circuit (11) is connected with an in-vehicle battery (5) to form a heating loop for heating the in-vehicle battery (5).