BU-301: A look at Old and New Battery Packaging

Discover familiar battery formats, some of which going back to the late 1800s.

Early batteries of the 1700s and 1800s were mostly encased in glass jars, and as the batteries grew in size, sealed wooden containers were used. There were few standards, except perhaps the old No. 6 Dry Cell, a designation most likely given because the cell measured six inches in height. All the rest were improvised and hand-built cells for specific uses. With the need for more portability, sealed cylindrical cells appeared that eventually led to some standardization in format. In around 1917, the National Institute of Standards and Technology formalized the alphabet nomenclature that is still used today. Table 1 summarizes these historic and current battery sizes.

In the early days, standardization involved primary cells mostly in carbon-zinc; alkaline came only in the early 1960s. With the advent of the sealed nickel-cadmium batteries in the 1950s and 1960s, new sizes appeared, many of which were derived from the standard “A” and “C” sizes. Manufacturers of lithium-ion departed from the conventional sizes and invented their own formats of cylindrical, prismatic and pouch shapes. The 18650 and 26650 are examples of cylindrical formats.

The International Electrochemical Commission (IEC) developed standards for most rechargeable batteries under the number of 600086. The relevant US standards are the ANSI C18 series developed by US National Electrical Manufacturers Association (NEMA).

For cylindrical cells, the first two digits designate the diameter in millimeters; the next three digits are the length in tenths of millimeters. The 18650 and 26650 are examples of cylindrical formats. The 18650 is 18mm in diameter and 65.0mm in length. Prismatic cells use the first two digits to indicate the thickness in tenth of millimeters. The next two digits designate the widths and the last two provide the length of the cell in millimeters. The 564646P prismatic cell, for example, is 5.6mm thick, 46mm wide and 56mm long. P stands for prismatic. Because of the large variety of chemistries and their diversity within, battery cells do not mark the chemistry.

Looking at the batteries in mobile phone and laptop, one realizes a departure of established standards or the inability to agree on new ones. Most consumer devices come with their own custom-made battery. Compact design, high volume and tailoring a product to exact market demands gravitate away from suggested standards, introducing many sizes that are short-lived.





F cell

33 x 91 mm

Introduced in 1896 for lanterns; later used for radios; only available in nickel-cadmium today

E cell


Introduced ca. 1905 to power box lanterns and hobby applications. Discontinued ca. 1980

D cell

34.2 x 61.5mm

Introduced in 1898 for flashlights and radios; still current


22.2 x 42.9mm

Cordless tool battery. Other sizes are ½, 4/5 and 5/4 sub-C lengths. Mostly NiCd.

B cell

20.1 x 56.8mm

Introduced in 1900 for portable lighting, including bicycle lights in Europe; discontinued in in North America in 2001 

A cell

17 x 50mm

Only available as a NiCd or NiMH cell; also available in 2/3 and 4/5 size. Popular in old laptops and hobby batteries.

AA cell

14.5 x 50mm

Introduced in 1907 known as penlight batteries for pocket lights, spy tool in WWI; added to ANSI standard in 1947.

AAA cell

10.5 x 44.5mm

Developed in 1954 to reduce size for Kodak and Polaroid cameras. Added to ANSI standard in 1959

AAAA cell

8.3 x 42.5mm

Offshoot of 9V, since 1990s; used for laser pointers, LED penlights, computer styli, headphone amplifiers.

4.5V battery

67 x 62
x 22mm

Three cells form a flat pack; short terminal strip is positive, long strip is negative; common in Europe, Russia

9V battery

48.5 x 26.5
x 17.5mm

Introduced in 1956 for transistor radios; contains six prismatic or AAAA cells. Added to ANSI standard in 1959


18 x 65mm

Developed in the mid-1990s for lithium-ion-ion; commonly used in laptops, e-bikes, including Tesla EV cars


26 x 65mm

Larger Li-ion battery for industrial applications


26 x 70mm

Same as 26650 with slightly larger diameter. Common as LiFeO4 for wheeled mobility, UPS and hobby use

Table 1: Common old and new battery norms. Some sizes come in fractural lengths mostly in nickel-based chemistries.

When first invented, a battery was perceived as being “big” and this reflects in the sizing convention. While “F” was chosen as a medium-size battery in the late 1800s, our forefathers did not anticipate the need for miniature batteries. Running out of letters towards smaller sizes brought on the awkward designations of AA, AAA and AAAA. It’s also interesting that many sizes never took off and “A” was replaced with the thinner “AA.”

A successful standard for a cylindrical cell is the 18650. Developed in the mid 1990s for lithium-ion, these cells are used for laptops, electric bicycles and even electric vehicles, such as the Tesla Roadster car.

Since the introduction of the 9V battery in 1956, no new consumer format has emerged. Meanwhile, portable devices have lowered the operating voltages and 9V is overkill. The 9V battery is expensive to manufacture and has a low specific energy. A 3.6V battery alternative should be offered in primary and secondary versions with different chemistries. Similar in size to the 9V, this pack would be protected with unique battery terminals that would only allow charging secondary batteries. A code would apply the appropriate algorithm.

Starter batteries for cars also follow battery norms, which consist of the North American BCI, the European DIN and the Japanese JIS standards. These batteries are similar in footprint to allow easy interchange. In an effort to standardize, all American car manufacturers are in the process of converting to the American DIN size batteries. Most manufacturers of deep-cycle and stationary batteries produce their own sizes and the replacement must be sourced from the original maker. Standardizing of the electric vehicle may be too early. Forcing the issue could follow the failed attempt to standardize laptop batteries in the 1990s.

Last updated 12/23/2014


On March 1, 2011 at 2:37am
Atul Gupta wrote:

i have seen some Li-ion pouch cells packaging with terminals on top. can we mount the same cell in 90 Deg rotation condition i.e. terminals are in side instead of top?

On August 18, 2011 at 11:00am
Steven wrote:

The B cell battery is 20.1 millimeters in diameter and 56.8 millimeters in length. It is still in use in Europe.

On February 17, 2012 at 3:58pm
BWMichael wrote:

Atul Gupta: Of course. You could easily modify the battery yourself to have the contacts on the side. Or just turn the battery 90 degrees? I see mobile phone batteries all the time which go in the phone sideways, the contacts being on the side of the phone.

On December 21, 2012 at 9:42pm
Matty deBarri wrote:

Slight correction to table 1:  26700 slightly longer than 26650 (5mm).  Diameters identical.

On October 25, 2013 at 11:20am
Eric Q wrote:

There are also two even larger sizes of Li-Ion batteries which are used in flashlights, among other things.  They are, the 32600(32mm X 60mm) which is about the size of “D” cell; and the 32650(32mm X 65mm), just slightly longer, the largest cylindrical size that I am aware of.  It’s a continuation of the 18650 and 26650 format, which allows an even higher capacity.  There are also similar numbered sizes, such as 14500, and 10440, which are equivalent to the “AA” and “AAA”, respectively; and many, many other variations.

On November 23, 2013 at 7:17pm
Heiko wrote:

I didn’t know the 18650 were used in almost all laptop batteries and even electric vehicles.

But they are also typical batteries for modern led flashlights, I learned about them looking for a professional head-mounted flashlight - I finally got a Spark headlight and two 3400mAh protected 18650s with Panasonic cells. Perfect combination, that thing is an intense flood light and the batteries last for hours on full power smile

On December 13, 2013 at 8:52am
ian wrote:

There used to be a flashlight size called Double-D.  It was twice the length of a d-cell and put out 3v.  It was popular in the maglite style flashlights of the 60’s and 70’s.  Could use them anywhere you had a 2-d stack.

On August 3, 2014 at 7:48pm
Edward wrote:

i am a battery engineer in a battery company, any battery questions please email to me zzrm316@163.com Edward