Li-Ion BMS

My book “Battery Management Systems for Large Lithium-Ion Battery Packs” was just published.

The process started 11  months ago (mid November ‘09), when the publisher, Artech House, send me a generic postcard asking if I had a book in me. It turns out I did, and I didn’t even know it. I signed their contract, which stipulated that the book would have to be finished by the end of April: that would give me 4-1/2 months to write it. But, the published didn’t sign the contract until 6 weeks later, in February, meaning that now I had only 3 months to write the book!

I wrote the book in secret: I didn’t want to jinx it by talking about it. I only told the few people whose products I was describing, to get them to review what I wrote.

It was a grueling job. The worst part was preparing the index, which, in the end, I paid a professional to do. Now I understand why many authors only write one book.

Each time I finished a chapter, I sent it to the publisher for review. The publisher in turn passed it to a reviewer they hired, keeping from dealing directly with him; though I really knew it was Bill Cantor, Vice-President of Technology, at TPI in Shrewsbury, PA, and an expert in Lead Acid BMS. I would get Bill’s reviews a month afterward, which was not as useful as if I had received them more promptly. But Bill gave me some very valuable insights; for example, the entire chapter 1, discussing Li-Ion cells, came about because of his suggestion. The stipulation was that anything that the reviewer flagged had to be addressed in the book; now I know that that’s bogus: no one checked, so I was really free to take anything worthwhile from Bill’s reviews, and the rest I could safely ignore.

Artech House was not ready for the manuscript on the original due date, so they moved it to May 17th, though they presented it as if it was to help me, which it certainly did. I was done on the 16th, a day early; the book took 3-1/2 month to write, which I did part time, while also running the company, Elithion. I understand that is quite fast.

The publisher wanted the manuscript on paper (2 copies) and CD, FedExed to them so that it would be in their hands on the 17th; this being 2010, I thought that was an anachronistic request: instead I upload it on line and gave them a link. They said that 2 hard copies were required, to allow me to check the result, and for them to compare the book to the hard copy. I insisted that I was not going to print it, because, even if I did so,  I would just ship it unchecked. Finally, they agreed to print it themselves, which saved be a great hassle and for which I am very grateful.

For some strange reason, for the illustrations, the publisher would only take TIFF files (for pictures) and Illustrator files 9for graphics); they would not take PDF files. I wasn’t about to buy Illustrator, and especially I wasn’t about to learn how to use it. Hiring a graphics person to do my drawings was out of the question, not just because of the cost, but because it would deprive me from the ability to change a drawing on the spur of the moment. So I used whatever application worked best (my schematic program (McCAD), a flow chart drawing program (Diagram Designer), a spreadsheet program (Open Office’s Calc), and even Paint), and printed it to TIFF files, using high resolution). The publisher wasn’t happy. They asked me to send original files, which I did to humor them, knowing full well that there was no way they could open them.) Eventually, they accepted the TIFF files, and that was good: the pictures look great.

The book was scheduled for publication at the beginning of September, leaving 3-1/2 months for the editing process. I figured that during that time they would proofread the book carefully; now I know that it wasn’t proofread: there are many silly errors left in the book; yes, I made the errors, but they sure didn’t catch them.

In the end, the book was published, as planned on the 30th of September. Soon thereafter, a few people started telling me that they got their copies; yet, I still hadn’t received mine! Finally I got my 10 copies 2 weeks later; that was really exciting!

As the Lithiumate BMS is selling steadily and requires less and less of my time for support and manufacturing management, I have now shifted my attention to a new design, the Lithiumotive.

As the name implies, the Lithiumotive is a Li-Ion BMS designed specifically for the automotive market, though its ruggedness makes it appropriate also for marine applications; its wide scalability makes it ideal for land-based, large storage facilities.

The Lithiumotive design is in response to the various request we received from Lithiumate users:

• “I need redundancy”
• “I need support for more than 256 cells in series”
• “I need a sealed product”
• “I need absolute immunity to electrical noise”
• “I prefer spaghetti wiring to distributed cell boards”
• “I love the Linear Technology LTC6802 chips”
• “I need active balancing”
• “I need to make full use of all the energy in each and every cell”

So I went to the drawing board, with the goal of meeting all these requirements.

So far it’s coming along quite nicely. The biggest challenge? Connectors. Selecting connectors that are automotive grade, sealed, available, not too expensive, can handle the high voltage or the high current, has taken many days. Other than that, the electronics and the software are easy, especially after they have been validated by the Lithiumate’s success in the field.

The BMS family consist of 6 modules:

• Master
• HVFE (High Voltage Front End)
• Slaves: wired, optical, spaghetti, redistributor

Lithiumotive module

A system requires a master, an HVFE, and one and more slave, of any type. The various modules communicate through a dedicated CAN bus (digital BMS) plus a daisy chain (redundant, analog BMS).

The Lithiumotive is a professional product, and will only be marketed to professional industries (we will continue to provide the Lithiumate to hobbyists). Its release has not been announced, but it will be no sooner than the 2nd quarter of 2011.

We are in Seattle, WA, for the bankruptcy hearing of EV Components (or what’s left of it).

This area is a hotbed of EV related activity!

Yesterday we visited with Rich Rudman, of Manzanita Micro, in Kingston WA.  We saw Manzanita Micro’s new headquarters: an elegant, spacious building with lots of garage space and tasteful offices up stairs. Rich’ “gnomes” are busily building product (pretty much everything is done in house), while he and his partners are developing more and greater things. One of those partners is Mike Willmon, formerly of EV Components, who we were glad to meet.

Later, I met Jake Oshins, a fellow Sparrownaut, who showed me his Li-Ion converted Sparrow (I did a similar conversion to my Sparrow).

—

The bankruptcy hearing was in Downtown Seattle. As we were walking out of the parking lot, we heard a scraping sound: it was a sports car scraping its bottom entering the parking garage: a Tesla. A Tesla? I wonder who that might be!

Upstairs we met Ken Vatz, the lawyer hired by EV Components’ clients to do a class action suit against that company. Nice man, obviously quite smart. We also met Dave Kois, finally, after such a long time working together long distance.

The hearing was in a courtroom. The trustee and his secretary were sitting on one side of a table, facing the audience. Chairs across the table were for the people being questioned. The meeting started exactly on time, and the first two cases were heard rapidly.

Then came the turn of EV Components. The man from EV Components and his lawyer joined  the Trustee and his assistant at their table. Three of those people were dressed professionally and appropriately for the occasion.

We all sat in the second row, yet we could not hear very much of what was being said. Ken and Dave moved closer, to hear better. But it was clear that the Trustee knew what he was doing, had studied the case, and was quite good at challenging the man’s statements with pointed questions.

Afterward, the Trustee asked if there were any creditors in the courtroom. Ken stood up and gave a succinct but effective rebuttal to the man’s claims. At one point the lawyer objected to Ken’s line, but Ken quickly replied and continued making his points, ending with a request for dismissal of EV Components’ bankruptcy request. The Trustee replied that that was an option, but that he needed to consider other options as well, and that he wished to talk to his own lawyer before he could make a decision. He was definitely non-committal.

Dave offered the Trustee a list of EV Components inc.’s inventory at the time of his departure in April, which the Trustee gladly accepted given that the man had stated that the last inventory was taken in March (before EV Components inc. was formed).

The Trustee asked whether any other creditors were present, so I stood up a briefly described that EV Components owes Elithion $ 12,8 K.

Then, the Trustee closed the hearing. The man and his lawyer left first, quickly, without looking at us.