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Battery holder
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A battery holder is one or more compartments or chambers for holding a battery or batteries.
In the case of dry cells the holder is also usually responsible for making electrical contact.
In the case of wet cells cables normally make contact with posts or terminals like commonly found
on automobiles or emergency lighting and power. Battery holders developed in parallel
with batteries over time and as battery package sizes shrunk so did the holders.
Today's battery holders typically are either a plastic case with the shape molded
in the housing as a compartment that accepts batteries or a separate plastic holder that
is mounted with screws, eyelets, glued or double sided taped down.
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Encyclopedia
A battery holder is one or more compartments or chambers for holding a battery or batteries.
In the case of dry cells the holder is also usually responsible for making electrical contact.
In the case of wet cells cables normally make contact with posts or terminals like commonly found
on automobiles or emergency lighting and power. Battery holders developed in parallel
with batteries over time and as battery package sizes shrunk so did the holders.
Today's battery holders typically are either a plastic case with the shape molded
in the housing as a compartment that accepts batteries or a separate plastic holder that
is mounted with screws, eyelets, glued or double sided taped down. New retainers have been designed for coin cells on surface mount boards.
Using either coiled spring wire or flat tabs that press against the battery are the two
most common methods of making the electrical connection inside a holder.
External connections on battery holders are usually made by contacts with the following feature: PC pins, Surface mount feet, solder lugs or wire leads.
History
In the late 1800s patents were issued for consumer products like flashlights and radios, patent no. 617,592 is dated March 1898 for an early metal flashlight that accepted D batteries.
1900s, Some early battery holders were often no more than a cardboard box with copper contacts. By the 1920's battery holders used twin metal clips like fuse holders to hold the battery. Patent no. 1,439,429 was granted Dec 12 1922 for an assembly with two spring arm clips, a small switch and lamp assembly on the end of wires.
The introduction of Polypropylene in the 1950's and the first miniature batteries by Eveready were the next big changes "small plastic battery holders"
These are still on the market today and common in toys, decorations and lighted or blinking items.
In 1957 electric wrist watches arrived on the scene and quickly gained popularity with the public.
In the 1980's the first circuit board mounting lithium coin cell battery holders appeared. As introduced in Dec 1984 under patent no 4,487,820 by M.P.D and still widely available today in the original form.
C. 1998. The electronics industry is shifting to surface mounted lithium battery holders or sockets as quickly as possible, Surface-mount technology C. 2001 Battery holders with pressure contacts become widely available in the market place along with increased use of sub A batteries. CR2/3A, CR1/2AA and CR123A batteries began in camera applications but expanded into new markets like alarms, hand held computers, keyfobs.
Design Considerations
How will the product be used, portable or stationary and under what conditions. Indoor, outdoor, beach, remote jungle, design for the worst case conditions that can be expected. Thermal cycling, vibration, ease of battery exchange, age range and physical condition of the intended user. These elements must be taken into account for a design to be successful and are part of the design process.
Your first choice is will the holder be part of the case or an additional part added later. To help decide one has to compare assembly, component, tooling and fixture costs with the cost of prefabricated holders.
A. Review a design check list (sample below) to be sure everything’s included like UL, CSA, RoHS, etc.
B. Amortize any tooling, setup, fixtures, minimums qty’s, misc. charges into the projected quantity to be produced.
Generally speaking it is easier to buy for small production runs and build-in a compartment for larger runs.
The majority of AAA, AA, C and D battery holders available on the market are made with polypropylene or nylon bodies rated for 80-100ºc. Lithium coin cell holders are made with high temperature PBT, nylon or LCP bodies because they normally are circuit board mounting and require wave soldering at 180-240ºc or reflow soldering and rated 260-300ºc.
Battery contacts are the most important part of the design and require serious consideration. Since batteries are nickel plated it is recommended the contacts be nickel plated to prevent galvanic corrosion between dissimilar metals.
Very generally speaking the design choices of battery contacts are: fixed contacts, flexible contacts and combinations of the two.
Fixed contacts , inexpensive but prone to loss of electrical connection.
Combination of fixed and flexible, better but subject to an open circuit upon movement in the direction away from the fixed position. Example, a spring compresses and the battery moves away from the fixed member.
Flexible contacts on both side of the battery, better resistance to loss of electrical connection upon movement of the battery.
Flexible contacts with multiple fingers touching the anode and cathode, Best !
Allows for movement in multiple directions without losing electrical connection.
Features like reverse battery protection can be part of the design. The contact for the anode side can be recessed behind plastic and receive a battery nub common on Alkaline batteries. Another method is a plastic channel to receive a battery post or terminal.
See also
External links
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