tesla battery temp monitor

whatever

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just a thought:
the white silicon type material which is in contact with the cells and transfers heat from the cells to the cooling
tubes . Since it is in contact with each cell, it might be possible to monitor the temp of each cell.
Some sort of strip built into the silicon with thermocouples or similar of micro size, something like an led strip but
an integral part of the white silicon. How to comunicate with each thermocouple considering the numbers involved I'm not sure but i'm guessing would be possible.
 
there are probably many ways to do it, but here is an interesting example of how a very thin optic fibre
could be used to gather the individual cell temp data
https://www.jove.com/video/54076/fiber-optic-distributed-sensors-for-high-resolution-temperature-field
 
seems there is a technique recently developed called
distributed temperature sensing using optic fibres.
in this paper

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0ahUKEwjJ68762ejXAhXCJpQKHZAPBvYQFghMMAU&url=http%3A%2F%2Flunainc.com%2Fwp-content%2Fuploads%2F2012%2F08%2FDistributed-Sensing-in-Single-and-Multi-mode-Fiber.pdf&usg=AOvVaw0rArlhZkeHIzyT0ftHjEzW

the authors say:
Our SWI technique is highly capable of measuring the spectral shift in the Rayleigh backscatter along an optical
fiber with high spatial resolution and spectral sensitivity. The linear relationship between strain or temperature and the spectral shift enables distributed sensing along any standard single-mode or gradient index multimode fiber with millimeter-range spatial resolution over tens of meters of fiber with strain and temperature resolution better than 1μe and 0.1 ºC. The instrument is robust and simple to use. In addition, as the measurement does not require specialty fiber or discrete elements, sensors are very economical.

This might be ideal for tesla battery module, as the resolution is down to mm level ( each cell temperature would be easily recognised) and it works over a length of 10m or so of optic fibre ( probably long enough for each battery module). It would allow to recognise early which cells are generating more heat and likely to fail. Although the tesla battery is not designed for easy replacement of individual cells it might be integrated into later iterations of the design.
Just a thought.
 
In fact, Linear Technology has a more pragmatic approach to this.

In their LTC680x application notes, they suggest using diodes in series/parallel to monitor individual cell temperatures. Each cell has its diode and a few diodes are placed in // to make a diode bank to be compared to others.

Whenever a diode bank has a lower forward voltage than others, it means one of the cells is overheating. (Vf decreases with temperature)

You don't get 1°C accuracy but 30°C+ abnormalities are made visible using this cheap technique that does not require 1ADC channel per cell.
 
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