Galvanic Isolation Circuit for Battery Pack Communication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Battery packs with low side FETs face issues of excessive current consumption and potential damage from high voltage when communicating with external systems, leading to overcurrent, low-voltage failures, and system hardware failures.
Innovation Solution
A communication system for battery packs that includes a transmitter and receiver configuration using transistors and diodes to separate the battery pack's ground from the external system's ground, preventing excessive current consumption and high voltage damage, with P-type and N-type transistors and diodes controlling signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a low side FET is used in the battery pack communication system, then the battery management system can control the protection FET gate with respect to battery ground voltage, but the communication unit may consume excessive current and be damaged by high voltage when communicating with external systems
Solution Approach 1:
The communication system is divided into two separate ground domains: battery pack ground and external system ground. The galvanic isolation device creates distinct electrical domains that are physically separated, allowing the communication unit to operate safely within its own ground reference without being exposed to external system voltage fluctuations or high voltage conditions.
Solution Approach 2:
A galvanic isolation device acts as an intermediary between the battery pack communication unit and the external system. This isolation device includes separate primary and secondary sides with coupled inductors that transfer signals while blocking direct electrical connection, thereby preventing high voltage from reaching the communication unit while still enabling bidirectional communication.
2Productivity
If the battery pack ground and external system ground are electrically connected, then communication signals can be transmitted directly, but excessive current may occur leading to overcurrent, low-voltage failure, and system hardware failure
Solution Approach 1:
The galvanic isolation device serves as a mediator that enables communication signal transmission while preventing direct current flow between the battery pack and external system. The coupled inductors transfer magnetic flux to convey signals without providing a direct electrical path for excessive current, thus maintaining communication efficiency while eliminating the harmful current path.
Solution Approach 2:
The electrical connection is segmented into magnetically coupled but electrically isolated paths. The primary side inductor and secondary side inductor are positioned to couple magnetic flux while maintaining physical separation of windings, creating multiple isolated current paths that prevent excessive current from flowing through the communication unit.
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
The solution effectively prevents excessive current consumption and hardware damage by physically separating the battery pack's ground from the external system's ground, ensuring safe and reliable communication.
Implementation Method 1
a first transistor configured to perform a switching operation in response to a first communication signal output from a battery management system (BMS) of the battery pack; a second transistor configured to perform a switching operation in response to the switching operation of the first transistor
Implementation Method 2
a first diode configured to transmit the first communication signal to the external device in response to the switching operations of the first and second transistors
Implementation Method 3
a third transistor configured to perform a switching operation in response to a second communication signal received from the external device; a fourth transistor configured to perform a switching operation in response to the switching operation of the third transistor
Implementation Method 4
a second diode configured to transmit the second communication signal to the BMS in response to the switching operations of the third and fourth transistors
Data Source
AI summary
Provided are a communication system of a battery pack, and a battery pack including the communication system. According to an embodiment of the present disclosure, the communication system includes a transmitter configured to transmit a communication signal from the battery pack to an external device and a receiver configured to receive a communication signal from the external device, wherein the transmitter includes: a first transistor configured to perform a switching operation in response to a first communication signal output from a battery management system (BMS) of the battery pack; a second transistor configured to perform a switching operation in response to the switching operation of the first transistor; and a first diode configured to transmit the first communication signal to the external device in response to the switching operations of the first and second transistors, wherein the receiver includes: a third transistor configured to perform a switching operation in response to a second communication signal received from the external device; a fourth transistor configured to perform a switching operation in response to the switching operation of the third transistor; and a second diode configured to transmit the second communication signal to the BMS in response to the switching operations of the second and fourth transistors.