Tesla Batteries

Moksha D -

Hi everyone and welcome back to my blog! 

This week I had the privilege of seeing lithium-ion batteries in person and to many people’s interest, they were Tesla batteries. 

Tesla not only makes batteries for cars, but also batteries for utility companies like Salt River Project, SRP. SRP purchases some of their lithium-ion batteries from Tesla as storage units for solar energy. These units are known as megapacks. 

Pictured below is a 12kv feeder which goes to 4 way switches. The switches have different configurations that communicate to transformers in different ways allowing them to stay on or off. 

 

12kv feeder to 4 way switches

Each transformer is associated with a Tesla megapack (a lithium-ion battery for storage) which is pictured below. 

 

Tesla megapack

 

The megapacks have labels which describe the voltage and current that it has. Below is an example of what a label looks like. 

 

Megapack label

 

The 2899.2kWh means that it can discharge power for about 4 hours considering it has 724.8kw. Each megapack can have a different kWh. 

 

Underneath the megapacks, are cooling units to ensure they stay at a consistent temperature so it does not catch on fire. Other safety features include keeping the megapacks at least 6 inches apart and then each unit around 14 feet apart.

In case a pack catches on fire, it will stay contained to one pack and not destroy all of them. The fronts of the packs face opposite ways to uphold these regulations as well. Space is a huge safety feature when dealing with batteries. 

Seen below is the configuration they keep the Tesla megapacks in to ensure a fire will not penetrate more than one. 

 

Tesla megapacks setup

 

Luckily in Arizona, because of how much space we have, it is relatively easy to keep these megapacks at a good distance from each other. If they are all confined to one building, it is very difficult to prevent a fire from spreading. 

Because these are in packs, if one catches on fire, there is a guarantee that there is no human inside whereas when batteries are kept in a building where engineers could be researching, there is a lot of potential energy stored in one place. If something catches on fire, when a firefighter opens the door and the air mixes, this can cause explosions which are catastrophic for both the batteries and the people inside. 

Pictured below is where all the information about these battery packs is fed.

 

Information from packs

 

This information then goes to a control room pictured below where the engineers can see the condition of each pack and whether they are on or off or if there are any problems with them.

 

Control room

 

As you can see, all the boxes on the computer are green meaning all the packs were in good condition at the time. 

Next week, I will talk more about the efficiency of these packs, safety features, and public perception. Thank you for reading!

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Comments:

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    Mr White
    Hey Moksha, I really like how you highlighted the safety of the battery storage. I was watching an episode of Grand Tour, and one of the electric cars crashed and would keep catching fire up to 5 days after the crash because of the damaged battery cells, mostly because of the extremely close proximity of all the cells. I'm glad that, in non-automobile application, many more precaution's are taken to prevent catastrophic outcomes!
    rohan_k
    Hi Moksha. It's interesting to see how data is collected and fed into a computer system for monitoring the megapacks. How expensive is it to replace one if it deteriorates?
    Moksha Dalal
    Thank you Mr. White! Because these batteries are so large, making sure they have enough space between them is critical as the fires would be extremely large and hard to contain.
    Moksha Dalal
    Hi Rohan! Each megapack (depicted in the second picture) costs $1.24 million. This location specifically had 34 megapacks making the value $42 million for all the batteries.
    nicholas_a
    Hi Moksha, where are these batteries typically located?
    Kashish
    Hi Moksha, this is really cool! I’m excited to learn more about the applications of these batteries!
    Moksha Dalal
    Thank you Kashish!
    Moksha Dalal
    Hi Nick! Usually SRP keeps these battery sites in the suburbs of the city away from the public. In case one catches on fire, they want to ensure it is away from residential areas and the public does not panic that something is on fire without knowing the safety measures that are being used.
    camillebennett
    So interesting!!! Does the external temperature of where the batteries are stored affect their safety or efficiency?

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