18 minutes reading time (3505 words)

Importance of Safety & Standards in Energy Storage Systems

India is on the verge of adopting energy storage systems in a big way. For the smooth adoption and operation of these systems, it is important to understand the safety standards and requirements of these systems right at the beginning of the journey.

Emerging Tech Radio (ETR) host, Netra Walawalkar spoke to global safety science leader, Dr. Judy Jeevarajan, VP & Executive Director, Electrochemical Safety Research Institute, Underwriters Laboratories (UL) to get insights into the importance of safety standards for energy storage systems, and how standards help achieve safety, security, and sustainability goals to meet quality and performance expectations, manage risk, and achieve regulatory compliance.

Dr. Judy Jeevarajan, VP & Executive Director, Electrochemical Safety Research Institute, Underwriters Laboratories (UL).

Q: Your journey in the field of chemistry began in  India. Please brief our listeners on your journey from Chennai to becoming VP of research at UL.

A: I was born and brought up in Chennai and my graduate degree was in chemistry. Soon after that, I went to Loyola College to do my master's, again, with chemistry as my major. In Loyola college, I performed my first research project in chemistry and I liked research.

After I got married, I moved to the United States. Here, I completed a master's degree at Notre Dame University majoring in Physical Chemistry, and completed my Ph.D. at the University of Alabama, Tuscaloosa. Here again, I majored in physical chemistry with a focus on electrochemistry.

Everything to do with batteries is related to electrochemistry. So, in my first job, when I was given the project of making electrolytes for batteries, I was very involved with that work and I also got an opportunity to do a postdoctoral research fellowship at Texas A&M University. In that project, I worked completely on batteries.

It was early times when, Lithium-ion was just being introduced into the commercial market and some of them were still in research form so I was able to, fortunately, get many different types of cells from commercial cell manufacturers and test them at Texas A&M University. That is where I got expansive knowledge into Lithium-ion cells and batteries.

Soon after, our family had to move to Houston and I was lucky to get a job as a NASA contractor, that was because we were still not citizens at that time. Five years into that job, I was able to get it converted to a civil servant because we were citizens by then. So, I was a Civil Servant at NASA for 11-and-a-half-years before I decided to switch my career and join UL.

I had been working with UL on collaborative research projects, so when I decided to do move out of NASA, it was natural for me to work with UL based on the type of research they were doing and because of their focus on safety -- which was their mission.

At the time, I joined as a Research Director at UL, and currently, I'm the VP, of Research. I have been the VP for almost seven years and I also head Electrochemical Safety Research Institute, where we also work on energy storage. Our big focus is on batteries, but they are also branching off into other forms of energy storage. A major part of it involves hydrogen storage and looking at other energy forms like capacitors and so on in the future.

Q: In India and around the world, people have started acknowledging the importance of sustainability, and corporates today have de-carbonization on their agenda, and net-zero is the buzzword. How do you see the role of UL in the current scenario with safety and standards?

A: I think they have a really big role to play because when we talk about the net-zero, green environment, and so on, they all need in some ways safety for a safer environment for the future generations.

So, with our mission being to always improve safety and make lives safer, I think UL plays a significant role. We do that in many ways, one is of course by setting standards. We also do a lot of research that goes hand-in-hand with not only, looking into new forms of renewable energy, but also in understanding their safety.

We are playing a very proactive in all the new forms of energy, renewable energy that could replace the existing forms of energy that are causing pollution and harm to human beings. To summarize, we will be playing a role involved in the research part of it, as well as, contributing to writing new standards or updating existing standards.

Q: In India, we are at the very beginning of the adoption of electric mobility, especially in the electric two-wheeler and three-wheeler space, however, there have been few incidences of electric vehicles catching fire. Therefore, safety concerns need to be on high priority so that consumers' confidence is not shaken, can you talk briefly about the process of coming up with safety standards for lithium-ion batteries and batteries of other chemistries?

A: Sure. The way standards are written at UL is, firstly, someone brings in a proposal to write a standard. So, we have several new stationary grid energy storage systems coming into being, say someone brings up a proposal saying these are large systems and we need to make sure they are safe where they are installed.

Then, we form a committee, it is called the Standards Technical Panel. In the panel, we have a group of a minimum of 30 people, and sometimes we do have a much larger group, too. This panel is usually populated with members from different sectors (government officials, manufacturers, users, regulators, installers, etc.) and anyone category cannot be 30 percent of the entire group, so we ensure there is a balance. 

Once the panel is formed, they write the first draft. Sometimes, this can take a few weeks or a few months to complete the draft, and then it is a consensus process. The members of the panel see if they have a majority vote for the draft for it to become a standard and then it is used as a standard that the people who want to get a UL certification.

Q: Do these standards evolve over a period? As new applications come up with specific technology for safe operations.

A: Yes. So, any member of the panel or even an outsider can bring in a proposal, if they think that something needs to be updated or reviewed.

The panel will then meet to find out whether that proposal is valid, and if there is enough data to support the new proposal. Once they do that, they will update the existing standard and again they will review. Depending on that, they will update the wording or they will redo the wording and they will publish a new document. 

It is a little bit easier for UL standards because we are a smaller organization so we can do things faster than the larger, standard-setting bodies like the IEC (The International Electrotechnical Commission). In a few organizations, they have a period of 3-5 years where no changes can be made. So you can submit proposals, but only when the time comes for the document to be updated, only then can the document be updated.

Q: So how much time does it typically take at UL for updating?

A: Again, it depends on the type of proposals that are brought in and whether a consensus can be reached quickly. Anywhere between 2-4 months they can make changes to the document.

Q: Great, could you talk about the international experience on the adoption of safety standards?

A: I do not have too much first-hand experience on the adoption of standards internationally, what I do know is that most of the installers, developers, developing a product like to complete standard and get the certification. And sometimes, they can do a self-certification. In that case, UL provides the capability to audit the facility and provide the certification.

There is also another nuance to it, in the sense that, you can get many types of certifications, and not everyone is aware of that. So, one is where you can get a full UL certification, and then there are some things that if you do only partial testing, you will get something called UL-listed.

Sometimes you might do a little bit more tests and not do the entire standard. And then, depending on the category of tests that are done, they may get a UL recognized certification.

So, there are different ways to get the certification, I would recommend that anyone who wants to get a certification, that they do the entire standard, all the requirements given in the standard so they have a rigorous process of going into what needs to be completed and verified, using the test methods and the test requires that are given in the standard. That way, they know for sure that the system they are setting up is fully safe.

If you look at the other side of it, when you don't do everything that you need to do and it results in a failure, then you invest a lot more money to do the investigation and understand why something failed.

If you complete all the certifications as needed in a very comprehensive manner then the amount of money you are spending, the time, and the name [product brand], will be better than having a failure and then doing some follow-ups to figure out what went wrong.

I would say invest at the very beginning and get a good product out than trying to go back and find out what went wrong. Internationally I find that some of the companies are in a hurry to go to the market without actually completing everything as they should do.

I would say invest at the very beginning and get a good product out than trying to go back and find out what went wrong. Internationally, I find that some of the companies are in a hurry to go to the market without actually completing everything as they should do.

by Dr. Judy Jeevarajan, VP & Executive Director, Electrochemical Safety Research Institute, Underwriters Laboratories (UL).

Q: Do it right at the beginning, that is very important. As you know, India is starting the Greenfield project for advanced chemistry cell manufacturing. It will be prudent to ensure proper standards are followed right from the manufacturing of cells to assembling and then going forward to stationary projects, EV batteries, and EV charging infrastructure. So, what role will standards play in India, in your opinion?

A: I think when you look at standards, standards help you verify the performance and the safety to a certain level but standards typically do not tell you how to manufacture a cell or how to manufacture a battery. It only tells you after your cell is made, once you run the tests, whether your cell is safe to a certain tolerance level. In the same way, it tells if your battery has been made to a certain safety level but it does not also push the cell or the battery beyond its limits.

So I think, when it comes down to manufacturing cells or batteries, it starts from the lab where the research is being done to the technology transfer that is being done till the industry and those things that are learned in the lab should be implemented in the industry.

It is very difficult to find a book that will tell you how to do the manufacturing process, although we are trying to do something like that based on our experience, it is not easy to find a standard that will tell you how to put things together. It comes from experience and practice.

But to figure out the end product you have made – be it cell, battery, or a system – whether it is working the way it should then I think standards play a very significant role in confirming that you have the product that you wanted in first place concerning safety.

That gives you the final confirmation that you did everything right and one of the things that are a little bit more complicated, especially when you start getting into stationary grid energy storage systems and so on is making sure that the design is done correctly, and the tests are done correctly, in a relevant way. So, you can understand the failures that can happen at different levels and not just in one test that would tell you whether the system as such is fast or not.

Q: What we notice in India is that electric two-wheelers generally do not have an active cooling system for battery packs so that may be the reason for having some fire incidents. Please touch upon the significance of the battery management system?

A: Yes, so when you look at a battery management system, the controls that are set in it should be relevant to the battery, cell chemistry, and the cell design so they should be set in a very stringent manner.

For instance, if you are looking at an over-charge, there should be at least two levels of control, I would prefer three levels of control in the battery pack. Similarly, when you look at over-discharge, most of the battery packs do not have a control for over-discharge because when you do an over-discharge test on a battery and you take it into extreme over-discharge, even at the cell level, the cell dies. So, they think that it is not a problem, but if you continuously over-discharge your battery beyond what the manufacturer tells you to, then you start building up the copper dissolves from the anode and it starts spreading on the electrodes as well as the separator. And then, it starts blocking the sites for intercalation as well de-intercalation, so at one point, you will have heat build-up and lithium Dendrite deposition, and domino runaway. And all this usually happens in the child's step, even without going into an over-charge.

So those are the things that people need to take into consideration and make sure that they are putting the right controls in place and not overlooking something. What I would say is when they look at the BMS, they need to make sure that all of the controls that need to be placed are placed and that they should not skip anything or cut any corners that would make the battery unsafe.

The BMS is important and what is inside the battery is also important.

When you take a look cooling system, it is not easy to put an active cooling system in a small battery pack as with an e-bike or an e-scooter. But, if the manufacturer of the battery did a good thermal analysis for the relevant configurations then they can find out which areas of battery are getting hotter from other areas and they can design heat dissipation paths that will remove the heat from areas that are getting hot.

So you can also not only have a small thermal gradient but when you have cells that are always similar to each other, then the life of your battery is longer and it is also safe. But, when you start having different thermal environments even within the battery pack, the values of the cells in terms of voltage and the internal assistance starts changing so much that now the battery has to work harder to achieve the charge or the discharge and so the life of the battery and its safety is compromised.

Q: So, if any OEM is purchasing cells from any supplier they have to ensure when they assemble packs,  they are packing a batch of cells that have similar internal resistance, right?

A: Yes. So, we recommend that the battery should be made from cells from the same manufacturing date lot.

Q: People do talk about performance cycle, life, and cost, but there is little understanding about safety standards. How do you see the enforcement of standards? What is your opinion about the enforcement of standards?

A: Standards for cells are voluntary, it is only the regulations that are mandatory. In many places, the regulations are placed by the government, and they are mandatory. But I think in certain countries like India, standards are also mandatory because it is done by the government with the support of the government.

I think that is a good thing because the government can now impose those regulations or standards on the people who are doing the lines. So, people need to follow standards, but the catch here is that many people who use it as a business plan or a business method where they find making batteries lucrative, do not even know sometimes that they have to meet some standards. I think that is where a lot of problems start to emerge that they are not even aware of, or they do not even have the knowledge that they have to do certain tests and get certified and meet certain standards.

I think building the awareness that these things need to be done is probably the first step that will help in having more people or more manufacturers complete what they need to do and make everything safe.

Q: Is there any database where there is a list of certified cells or certified manufacturers?

A: Yes, UL has a very large database on what products have certification and what type of certification. And I think, from what I have heard, it is a publicly available database. I do not know too much about others like the European CE standards and those but I am pretty sure that one can get that kind of information.

Q: You mentioned there is a difference between certification of cell versus certification of a total system date? 

A: Yes, there are different standards for each of them.

Q: In case of any fire accident in EVs, most responders should also be aware of how to react. So, what are your thoughts on training firefighters and first responders in that case?

A: Yes. I think that's very important because they are the first people on the scene when something happens. Based on the speed with which industry has gone forward with electric vehicles, be it two-wheelers or four-wheelers, or even trucks, there are many things we still do not know.

For instance, how do you know how much energy is left in the battery pack after the fire? Are the first responders safe enough to approach that vehicle or a particular system where there is energy left in certain parts of the entire battery?

The second thing is, is it continuing to burn? I know the question of fire suppression has been studied to a certain extent by certain groups, but it has not been optimized to the level that you can tell a firefighter, this is what you need to do to suppress the fire, for this type of battery or this type of system. So, I think there is a lot more that needs to be clearly understood and optimized.

And then the next step is to provide training. The training has to be provided to first responders and firefighters and all of this needs to be done in a very systematic manner.

The thing that I worry about is that everything is going at such a high speed that people are not stopping to think where the issue has been worked out, but are reacting to an event after the event has occurred. That is something that has been a concern for me.

Q: Coming to the end-user, how can they identify something is wrong with the battery and take some precautions ahead of time, or just make sure that something doesn't go wrong with their battery in terms of charging?

A: So it depends on the type of battery they have. We can take a simple example of an e-bike where people can feel the presence of the battery, right.

So a few things that they can look out for is whether the time it takes to charge the battery has changed. Then, if the battery is running down very quickly. If these things are happening, then that is something that they need to think about.

If they observe that the battery is getting too hot, more than what it normally does. At the most, the battery temperature should be 5-10 degrees higher than the ambient temperature of the environment even at the end of charge, if the battery is getting much hotter than that, then it is a sign that something is not okay.

Another thing to watch out for is, bulging. If people are using pouch format batteries those can swell. So, if they see any change in the shape or dimension of the battery pack then that is another thing to look at.

Lastly, I would say if they see any liquid coming out of the battery that could mean there is a leakage somewhere in the cells, so that is also something that they need to look out for and probably take for service or maintenance.

(The interview was conducted by Netra Walawalkar for ETR. The conversation has been transcribed and edited by Shraddha Kakade, Asst Editor, ETN). 

Author : Shraddha Kakade
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