Talk:18650 battery

Article is in dire need of expansion and modernization.

This article should be greatly expanded, as 18650 cells are quickly becoming the "new AA batteries" nowadays. (They are found not just in EV cars and laptop battery packs but also in portable radios, cordless tools and flashlights, etc.)

First of all, the article should explain that 18 x 65mm refers just to the size of energy production enclosure. That's because 18650 cells come in two major varieties: unprotected and protected, which are of different lenght but have the same diameter. Unprotected cells must only be used in "smart" devices, because "dumb" (un-monitored and un-regulated) charging can literally set Lithium-ion chemistry on fire and metal fires are notoriously hard to extinguish. Yet, very small and cheap devices (like single cell powered pocket torchlights) cannot afford such circuitry, so they must use 18650 cells which incorporate self-protection in themselves. Those cells are app. 5mm longer, because the monitoring chip and emergency fuse are installed at the + end of the energy producing enclosure, held together and hidden from view by the colorful plastic sheet wrapping.

Beyond the issue of protection, 18650 cells are also differentiated by the steady and peak amperage / coloumb ratings, which they can supply to the device they power. Cells with high amperage (e.g for EV car or cordless power tool use) usually have less total mAh capacity than cells used in e.g. portable radiation detectors or pocket radios. Vendors usually wrap their cells in different colors of plastic sheet, to visibly differentiate high / mid / low amperage 18650 varieties. 78.131.76.159 (talk) 23:00, 4 November 2023 (UTC)

Fair enough! I'll add that aswell.  🇮🇱JayCubby🇮🇱  talk 17:41, 13 November 2023 (UTC)

Review of article

The lead section is actually fairly good for how short it is. I would say that the lead is not even a paragraph and more like three sentences, yet it clearly states the topic of the article, it's concise and doesn't include information that isn't said throughout the entire article. However, it is not up to date (last source was from mid 2024) and it does not have brief descriptions about the topic's major article sections. It just defines what a 18650 battery is, and jumps right into the chemistry of it.

This part is where the article falls off the wagon. On the Chemistry part of this page, it is incomplete. Citations are needed to figure out if the battery is lithium-based, if sodium-ion variants were made in 18650 batteries, and lithium-ion chemistry. There are about a grand total of 4 sentences in this section, which leads me to believe that this probably shouldn't have been a section and more of a blimp in a section, but I digress. The content of the article overall is consistent with the topic; the last source is from August 2024 so the information might not be up to date entirely, and it does not include any Wikipedia equity gaps.

The claims they make are general and neutral. The sections are made up of short sentences that focus on a specific part of the 18650 batteries whether it be its dimensions, the chemical used to charge the battery, its composition, what it's used for everything. All of these viewpoints though are underrepresented due to the amount of information on this article being approximately 3-4 paragraphs. It isn't persuasive nor is it a call-to-action style article. Just generic and neutral. The sources they do use for this information is scattershot which makes their claims seem biased and/or weak, but it holds up I think.

The sources vary from scholarly works from the Journal of Electrochemical Society to news articles about the most popular lithium-ion cells for batteries. It varies widely which means that this article probably isn't the most accurate with its sparse information. The sources aren't very current with some works going as far back as 1993, while the youngest article is from August 2024 (believe it or not it's the news article source). The sources that are shown on the article when I click it, all of them work as far as there being an actual book or article with words that pertain to this subject. The older sources from 1993-2015 seem to be the more reliable sources and the most scholarly as the more recent sources are more news article-style, promotionalesque sources. I think there could be more sources to put in here that are scholarly and up to date, given how useful this battery is (being used in the Tesla Model S and Tesla Model X cars). The sources are from a diverse selection of authors as well.

The article is well written to the amount of information this article has displayed. This article needs LOTS MORE information, but from what they have already, sentences are structured good. No grammatical errors, doesn't look like they were copied and pasted by ChatGPT, and are concise and straight to the point. However, the organization of this article could be better as I believe 3-4 sentences for a major section shouldn't happen.

The image they use capture what the inside of an 18650 battery looks like and I think it does its job well. It shows the circuitry and metals used to make the battery and it relates to the topic very well. The description could've been better in describing what it is. I don't know if it's necessarily visually appealing, but it works. I also believe it may be copyrighted but highly doubt it if this article has been up for 12 years and no one has taken down the picture yet.

The talk page is barren, last time someone talked in there was in 2014. The only topic that was being discussed throughout 2012-2014 was actually the missing part of the Chemistry major section and who was going to complete that. However, nobody answered until 2014 when someone said they would, but did not complete the offer.

This article clearly needs work. It is very unorganized, limited information, and doesn't have very reliable sources. Some sources need citations, others need a whole source. It is all over the place. It gets to the point however and doesn't have any misinformation. The status of this article is a Stub-Class article which I can figure given the lack of information on here. This article in my opinion is underdeveloped due to the aforementioned paragraphs above me.

My question relevant to this article is how much voltage does a 18650 battery need to properly work? I know batteries for a Tesla need lots of voltage so I'm wondering what the minimum is to make it work properly and maybe the maximum to where it starts overheating and burning up?

Mathis40 (talk) 00:36, 1 February 2026 (UTC)

@Mathis40, thank you for the detailed review. I will expand based on this. This was my first (and so far only) article, so it's far from perfect.

As for your last point, it depends. For li-ion 18650s, they are discharged down to about 2.7 volts under normal conditions, but (from my own experience) damage usually occurs if they are below 2v. Lithium dendrites start forming, among other problems. Usually they are fully charged at 4.2v, and they are not supposed to explode under any circumstances, per the EC61960-2011 standard, but might at more than half a volt overcharge.

This all depends on the cell brand, look up the datasheet for your cell. Cheers! JayCubby 00:46, 1 February 2026 (UTC)

Form Factor Inconsistency

There should probably also be some talk about the `0` on the end. This is a large amount of inconsistency in how it is used. According to the official spec, it is intended to be tenths of a millimeter (0.1mm), however some manufacturers are using it to denote the form factor of the cell (`0` being "cylindrical"). In addition, "18650" cells can also be longer than 65mm. Some manufacturers do not include the protection circuitry in the form factor. In both of these cases, the improper use is technically out of spec, but both of these issues are so widespread that it warrants explanation in the article. MyzMax (talk) 05:38, 26 June 2026 (UTC)