Panasonic 18650 ?

I am a very big fan of Panasonic products, now i read there are 18650 batteries with pcb from Panasonic, someone know this ? and where can i buy ?

Same question.

I am waiting for AW to come out with protected 18650 in 2500 mAh capacity, but estimated release date is unknown. Meanwhile, looking at other choices.

I have tried Panasonic 18650 in my MC-E flashlight. It gets more power than Ultrafire or Trustfire 18650 models...

But where can i buy them ??

A google search on CGR18650HG (the unprotected 1800 mAh Panasonic batteries model I have) produced:

http://www.1sourcecomponents.com/partinfo/CGR18650HG.htm

http://www.onlybatteries.com/showitem.asp?ItemID=15262

Thanks, but this are the unprotected, i will look a little bit more, if i find someone in Europe

Maxilux;

I have been using Panasonic, Sanyo & Sony #18650 Li-Ion batteries for many years in different capacities.

They have no protection PC boards, but have the normal over-current protection built in.

Out of over 500 batteries in daily use, I have never had a single one of them vent.

Larry

Duplicate Post

I'm using samsung unprotecteds from an old laptop battery pack, they work fine.

Panasonic has new NCR18650 2900mAh batteries. They can be safely discharged down to 2.5V and should be safer than LiCoO2 baterries (these are LiNiCoAlO2). I asked AW If he can get them, but the answer was negative, because they are available only for big corporate manufacturers. :mecry:

Statement retracted.

PTC element and a pressure release valve are good but they will not protect your cells from over(dis)charge. So even with these features it is generally not wise to use unprotected cells.

Statement retracted.

frank777 said:

The Panasonic 18650 batteries are one of the few models made in Japan as opposed to China. Many lithium-ion battery failures occur when tiny metallic dust particles found in ALL lithium-ion batteries are too highly concentrated in a single area within the battery. The eventual result can be thermal runaway. A PCB protection circuit will NOT help from this kind of failure. Additionally, PCB circuits have been known to fail, as one did on one of my Chinese made 18650's.

If you look at the statistics of lithium-ion battery failures, you'll see that most of the problems come from Chinese manufacturers who have a much higher amount of impurities (metallic dust particles). You cannot eliminate all the impurities in the manufacturing process, but you can certainly reduce them.

The Panasonic model CGR18650HG has a PTC element and a pressure release valve, both EXCELLENT safety features. This particular model has a capacity of only 1800 mAh, but again, this is done for safety. When you make battery capacity higher, you have to make the insulation protection plates much thinner...... a very dangerous trade-off. The Panasonic 18650 (model CGR18650HG) has received UL 1642 safety approval, something you will not see on Chinese made 18650s.

http://www.onlybatteries.com/showitem.asp?ItemID=15262

So, you can buy the Chinese 18650 models with PCB protection circuits, or you can buy the so-called "unprotected" Japanese made Panasonic batteries and drastically reduce your chance of failure in the first place. I tend to put my faith in the latter.

Click to expand...

Interesting post. Are there any other alternatives? Something with higher capacity, at least 2200 mAh?

Well, If you use more unprotected cells in series in your flashlight you can easily overdischarge them. I'm not saying that they will explode but they will be ruined.

frank777 said:

Underwriters Laboratory doesn't agree with you. They have set product safety standards for over 100 years. In their tests, the most important element was quality battery cell construction and standard reliable safety features. A protection circuit, although it does enhance safety, is not THE major contributor to lithium-ion battery safety. You may find it valuable to read UL 1642 standards.

UL tests lithium-ion batteries based on the following:

Abnormal Charging
Forced-Discharge Test
Crush Test
Impact Test
Shock Test
Vibration Test
Heating Test
Temperature Cycling Test
Low Pressure

A PCB protection circuit only addresses a few of these. Most are function of battery construction.

Click to expand...

Section 1.3 of UL 1642 clearly states:
"...The final acceptability of these batteries is dependent on their use in a complete product that complies with the requirements applicable to such product."

In other words (as i interpret them), the final product needs to comply with the requirements laid forth by the manufacture of the cells. In the case of LiCo cells, this means a form of charge and discharge cutoff, as well as maximum current thresholds, to protected those cells. In flashlights, those devices are not built in, so we are required to either provide protection manually or by selecting cells with the PCB built in.

I am no fan of poorly made and often improperly stored off-brand ("fire"-brand etc) cells. I agree that the manufacture process of many cells out there leaves much to be desired, and the results speak for themselves in product inconsistency. The only reports I can recall, of loose li-ion cell explosion, were cells from less than reputable points of origin and name.

However, no amount of impurity elimination will protect a user from the results of a LiCo cell that is repeatedly operated outside of the recommended range of acceptable voltage and/or load. The highest quality impurity free Japanese or US made LiCo cell can explode if abused. UL 1642 states this in more or less words.

------------------

Other areas of specific interest in UL 1642 worth mention....

Section 4.3.1 (in more or less words): "Shall be protected from abnormal charging currents..." not required in the device that drains the cell unless it is also the device that charges the cell, or in applications where a battery has been tested and approved as "safe chemistry" with no risk of explosion....

Table 6.2: Short circuit and abnormal discharge tests must be done 5 times on 5 cells to conform to the standards laid forth.
(my commentsAbnormal discharges could happen many more times than this in applications where an uninformed user were repeatedly using unprotected cells improperly.

Section 8.1: Makes note of the fact that the tests being performed to qualify lithium cells are capable of causing lithium cells to explode.

Section 10.4: Points out that exceptions to the short circuit test are made for those cells containing PTC devices that prevent a continuous short circuited discharge from completing. (this is most LiCo cells with PTC). The test is performed instead with the maximum possible load that does not trip the protective device. The reason I bring this up is that this is one of MANY areas in the UL 1642 criteria that makes exceptions to the testing criteria for particular cell designs that prevent the test from being completed as stated.

--------------------

If I had to choose a LiCo cell for someone to use in a device that contains no protective measures for a li-ion cell, that does not have experience with Li-Ion cells, I would absolutely, without a flinch, recommend a protected cell from a reputable manufacture (Wolf-Eyes, Pila, AW), long before recommending an unprotected cell that has achieved UL 1642.

Eric

Statement retracted.

Hello Frank,

I happen to think that the impurities in the cells did play a part in the Li-Ion problems, but the bigger problem had to do with cell imbalance in the battery packs. The RC people ran into this quite a while ago and solved it by incorporating balancing leads into pack design. It now seems that the laptop battery pack manufactures have also added balancing leads in their packs.

In normal use, a cell with higher impurities will degrade faster. In a battery pack, this allows a cell to behave differently, including different charging and discharging characteristics. You will notice that almost all of the battery problems occurred during charging. This leads me to think the cells in the pack got out of balance and a cell was forced to a higher voltage and rapidly vented with flame.

There is no doubt that impurities within the cells was involved, but the bigger picture is the balance of the cells within the battery pack.

Tom

I would be comfortable with an even larger font size. I'm making sure that the most important point of the post is very well highlighted. You have misinterpreted the UL listing that you have linked to. It is a dangerous misinterpretation to be spreading around, especially when the UL listing you have linked to, makes specific mention of meeting manufacture requirements in completed installations in order to meet the UL standard. In a loose cell application, the ONLY way to meet those requirements is to install a PCB. A loose Panasonic brand cell with no PCB being used in a flashlight with no low-voltage cutoff would not meet the UL listing requirements any more than a cell made in cave in Afghanistan since the application would not be meeting the installation requirements set forth by Panasonic.

Searching the internet for a case of li-ion explosion related to over-discharge doesn't return results because people who've had li-ion cells explode as a result of repeated abuse have no clue why the cell exploded in the first place (if they knew that their use was abusing the cell and was likely to lead to an explosion then they probably wouldn't have been doing it in the first place), and would never even know to report it as a case of "explosion caused by over-discharge." There are very few people using loose li-ion cells with no electronic protection whatsoever in the world, so finding any relevant data that compares to the MASSIVE market of cheap cell phone and laptop battery replacements is impossible. Understanding how to interpret the data available is more important than finding it. I can easily do a search on the internet about exploding li-ion batteries and come to the conclusion that there are a large number of explosions occurring in consumer devices that seem to be linked solely to the quality of the cell in question.

However....

In how many exploding cell phone or laptop cases have you seen any investigation into the cause of the explosion? Anyone check to see if the charging circuit developed a short that caused the 5.5V from the power supply to go straight to the cell? Is this so completely impossible in a device like a cell phone that gets dropped and thrown around and beat up in women's purses all day? (Or in our case, does combat with a flashlight in a pocket all day?) What about cell deformation from the same sort of abuses? They are Poly cells after-all, and usually there is only a very thin piece of plastic between the cell and the back of the phone. Phones are getting slimmer and slimmer these days, which translates to less and less rigid.

What percentage of li-ion cells in the hands of consumers are completely unprotected, being used as loose cells? 1%? 0.01%? Probably less. What percentage of those unprotected cells are being used by people who are routinely over-discharging or over-charging those cells that would actually show up statistically in a market of such massive proportions. I think we all have to agree, that there are VERY FEW cases in the world where there is even potential to prove that an explosion would have been or could be caused by these circumstances because the sample size is so remarkably small.

I want to make it clear that I am NOT disputing your argument that cell safety is very closely related to the quality of cell construction. However, I would like to make the point that there is more to it than that. Perhaps the REASON we don't hear about cells exploding as a result of over-discharge and overcharging is directly linked to the fact that 99.9% (actually probably a higher percentage) of cells out there are in protected applications. Again, we have no way to verify the exact causes of many of those explosions. We do know that if you search youtube, you can find many examples of documented li-ion explosions that are created by the maker of the video, often times the method of getting the "fire started" is to simply bypass the safety net of the built in charging circuits and overcharge the cells.

More thoughts:

Sony has been regarded as one of the better li-ion cell manufactures, they even pioneered the industry in the early 90s, but they have had some of the largest cell recalls over the years due to safety issues relating to manufacture process. All of the recalls were on cells installed in consumer devices that would have already had appropriate cell "protection" in place. As I understand, the issue may have been directly related to cell manufacture being outsourced to china, where certain critical steps were ignored in the manufacture process. With that in mind, again, there is no disputing that the quality of the construction is very important to the safety of the cell.



Eric

I support mdocod in his posts and comments. There are many posts about all these same issues. Some of them are in the pinned topics at top of this section of forum.

For the record, the problem is not necessarily whether a battery is made in USA, Japan, Korea, China, Hong Kong, Mexico, Canada, etc etc.

The issue is the QA and reputation of the brand...while recognizing that some manufacturing locations/countries have better/worse quality standards and overall histories.