Around a year ago, I needed a replacement battery for my Samsung Galaxy SIII, which started a long series of posts encountering fake batteries. This provoked some responses, and a lot of interest, given the quality of the fake cells. I finally found a (believed to be) genuine cell and life was merry.
Or so I thought. Just a year on, the genuine cell I had decided to balloon out, just like the old one, pushing against the casing, leaning out so far as to occasionally lose contact and reset the phone.
The Curse of the Swollen Batteries
Swollen batteries are generally a big deal in the industry, and is one of the failure modes which have previously prompted recalls, as they can sometimes be the precursor to more destructive failure modes, such as an outright explosion. Most incidents are noticed by the user before they become too dangerous, and a small cut in the cell acting as a pressure relief vent often opens before something disastrous occurs, but it is a reminder of the volatility of Li-Ion chemistry.
The causes for swollen batteries are rather numerous. One of the main explanations involve the quality of the materials used in manufacturing. If the materials contain impurities, or excess humidity, this can cause gassing to develop during the charging process which causes the cell to balloon.
Another cause is overcharging. In Li-Ion, overcharging is not permissible, and many properly engineered systems take great lengths to ensure overcharging does not occur. This includes monitoring the temperature and voltage continually during charging and controlling the current accordingly. A failure of the charge controller to terminate the charge at the correct voltage can cause shortened cell life and swollen batteries.
Some seem to believe that swollen batteries tend to be due to storage at high states of charge. While it isn’t conclusive, generally, high states of charge cause voltage stress on the separator which could contribute to unwanted corrosion-style reactions. Unfortunately, I don’t know enough about the cells to explain this any further.
So, why did this battery end up swelling? Upon further reflection, it seems likely that manufacturing quality is probably a big part of the problem. The original cell I got with the phone was made 22nd June 2012, and the replacement claims to be manufactured 20th May 2012. This likely points to similar batches of material used in manufacturing. The original cell swelled to this state in about 1.5 years of use, with the replacement taking a year to reach the same state – again, a fairly similar amount of time.
Could the phone be sabotaging the battery? This is a distinct possibility, so I got out a multimeter and checked the charge termination voltage. The charge terminates reliably at 4.300v, as measured by an Agilent U1241B multimeter.
Modern cell phone batteries really push the boundaries of Lithium Ion chemistry, and in order to get a little more capacity out of the same sized cells, they tend to charge to slightly higher voltages than regular cells, and discharge deeper slightly deeper. This is why I really didn’t want a counterfeit cell as they are generally made to operate in the 3v to 4.2v “regular range”. The higher quality, high capacity cells, achieve their capacity by extending this range to about 2.8v to 4.35v. As the charge controllers are generally inside the phone, a counterfeit cell may be overcharged and overdischarged on every cycle resulting in a very short lifetime.
Unfortunately, such boundary-pushing also puts a lot of demands even on genuine cells, and if they aren’t made quite perfectly, then they will fail. It seems like this is the case with this one.
Sourcing Another Battery
Given that I did have a source of a (believed to be) genuine cell, why wouldn’t I purchase from them again? The phone is getting on a bit in terms of age, and the AU$50-ish cost to buy another genuine cell from them just wasn’t worth it.
Instead, I gave eBay another twirl, expecting to get a fake. Instead, I found a seller which claimed to have only genuine cells with working NFC functionality for a very reasonable AU$12.
This proved to be quite the mysterious item. Is it real, or is it a very very very good fake? I’ll let you be the judge – compare with this post.
Analyzing the Battery
The battery came in a thin plastic bag with a resealable edge and recycling logos printed in white. The battery inside seems to have a new style of print that doesn’t match either one of my former batteries. I suppose changes to packaging style is not unexpected over time.
Lets take a closer look at the cell printing itself.
The cell printing actually looks reasonable, with the label having very slightly rounded edges at the seam as expected. The battery claims to be “Manufactured by SDI”, which refers to Samsung SDI which is their energy solutions division. As nice as the label is, the text seems to have a slight thickness difference for the word China. Hmm. I’m not too sure.
The rear of the cell seems to have a mixture of font sizes, for the numbers in the brackets and for the phone numbers. It seems to be lacking a space after the word temperature/altas and the open-parenthesis, which I would expect if I was formatting the text. Inconsistently, between the word properly and call, the colon has a space on both sides, but that line omits a period at the end. I don’t have a genuine cell with this text to compare it with however.
On the upside, there is no obvious spelling mistakes on the label.
The printed datamatrix barcode does give some cause for concern. This datamatrix is low-density, and only encodes a simple string of GH43-03699A+AA1F920AS. My original battery encoded GH43-03699A+EB-L1G6LLU+C6NTX04261. The original battery string includes the model number and a alphanumeric string which is not related to the serial number (AA1C622TS/2-B). At least it does have some format resemblance and is not entirely garbage. I just hope that the serial number is unique. Anyway, this new cell does away with the manufacture date which seems a little strange.
Regardless, I have tested the cell and the NFC feature does work. This could be an indication that counterfeiters are getting much better and are able to include these features.
Lets go one step further, and start peeling back the label.
The label comes off rather smoothly, and reveals the NFC antenna on the cell, with a slight kink on the left side, mid-way up the cell. Looking at the end caps of the cells, we can see the “overlap” of the end into the battery area whose shape matches my original pretty much perfectly.
On the other side, we see a datamatrix code, some batch numbers and the correct cell type (i.e. an ICP515161A). Unusually, it claims to be made by Samsung SDIEM – I have no idea where the “EM” comes from, and I haven’t seen it elsewhere. If this is counterfeit, they’ve gone a long way.
I didn’t want to pull it apart any further, because I intended to use it, but for AU$12, this appears to be likely genuine in some way, but inconclusive based on the information I have. Good enough for an older phone, I suppose, provided it lasts.
Taking Apart the Old Swollen Replacement
As I have no use for the old swollen battery, I decided to peel it apart just to check.
The NFC antenna has that similar kink (the ripples are due to delamination in peeling the label back). The diagnostic text seems fairly similar, but the logo placement above the text differs.
The protection PCB has a single chip and a hardware fuse on a black PCB.
Again, it looks identical to my original battery that was my first swollen battery for the SIII. As a result, our conclusion that the Kogan supplied battery was a genuine was correct.