Thermal Runaway Overview

I created the following device after I saw a problem where expensive battery strings were being destroyed from thermal runaway.  Nothing came of the project but it was an interesting exercise in identifying a problem and creating a fix for it.  The device has four temperature sensor channels and four interrupt relays.  Temperature set points can be set through a serial interface with the device.  Alarms can be set for various temperature levels and a trip point can be set when a critical high temperature is reached.  When the trip point is reached, one or more of the relays will change state.  These relays are designed to interface with an under voltage release (UVR) breaker.  The relay interrupts the control signal to the breaker causing it to trip open and physically isolate the battery string from the charger.  There are two small signal relays to provide simple normally open (NO) dry contacts for alarm monitoring.  The following is a quick instruction manual I made for the device:

Thermal Runaway Detector/Interruptor Instruction Manual


Thermal Runaway Pictures

PCBs, Top

PCBs, Top

PCBs, Bottom

PCBs, Bottom

Printed Enclosure and Temperature Sensor Holders

Printed Enclosure and Temperature Sensor Holders

Assembled Device With Top Removed

Assembled Device With Top Removed

 
Assembled Device With Temperature Sensors Attached

Assembled Device With Temperature Sensors Attached

 

Thermal Runaway Schematics

Main Board And Temperature Sensors Schematic

Main Board And Temperature Sensors Schematic

IO Board Schematic

IO Board Schematic

HMI Board Schematic

HMI Board Schematic


Thermal Runaway PCB Designs

Main PCB Top Layer

Main PCB Top Layer

Main PCB Bottom Layer

Main PCB Bottom Layer

Main PCB Top, Bottom and Silkscreen Layers

Main PCB Top, Bottom and Silkscreen Layers

IO PCB Top Layer

IO PCB Top Layer

IO PCB Bottom Layer

IO PCB Bottom Layer

IO PCB Top, Bottom and Silkscreen Layers

IO PCB Top, Bottom and Silkscreen Layers

HMI PCB Top Layer

HMI PCB Top Layer

HMI PCB Bottom Layer

HMI PCB Bottom Layer

HMI PCB Top, Bottom and Silkscreen Layers

HMI PCB Top, Bottom and Silkscreen Layers

Temperature Sensor Top Layer

Temperature Sensor Top Layer

Temperature Sensor Bottom Layer

Temperature Sensor Bottom Layer

Temperature Sensor Top, Bottom and Silkscreen Layers

Temperature Sensor Top, Bottom and Silkscreen Layers


Thermal Runaway CAD Enclosure

CAD Enclosure

CAD Enclosure


Thermal Runaway Source Code

The source code for this project was developed using Atmel Studios.

Thermal_Runaway.h    Thermal_Runaway.c    Helper.h    Helper.c    LCD_Control.h

LCD_Control.c    EEPROM_Control.h    EEPROM_Control.c    USART_Control.h    USART_Control.c