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A battery holder is one or more compartments or chambers for holding a battery. For dry cells, the holder must also make electrical contact with the battery terminals. For wet cells, cables are often connected to the battery terminals, as is found in automobiles or emergency lighting equipment.
A battery holder is either a plastic case with the shape of the housing moulded as a compartment or compartments that accepts a battery or batteries, or a separate plastic holder that is mounted with screws, eyelets, glue, double-sided tape, or other means. Battery holders may have a lid to retain and protect the batteries or may be sealed to prevent damage to circuitry and components from battery leakage. Coiled spring wire or flat tabs that press against the battery terminals 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 pins, surface mount feet, solder lugs, or wire leads.
Where the battery is expected to last over the life of the product, no holder is necessary, and a tab welded to the battery terminals can be directly soldered to a printed circuit board.
In the late 1800s, patents were issued for consumer products like flashlights; US patent no. 617592 dated March 1898 is for an early metal flashlight that accepted D batteries.
Some early 1900s battery holders were often no more than a cardboard box with copper contacts. By the 1920s, battery holders used twin metal clips (like fuse holders) to hold the battery in place while making electrical contact. Patent no. 1439429 was granted in Dec. 1922 for an assembly with two spring arm clips, a small switch, and a lamp assembly on the end of connected wires.
The introduction of polypropylene in the 1950s and miniature batteries by Eveready allowed for the use of small plastic battery holders. These are still common in toys, decorations, and lighted or blinking items. In 1957, electric wrist watches gained popularity with the public.
Battery holders developed in parallel with batteries over time; as battery-package sizes shrank so did the holders. In the 1980s, the first circuit board mounting lithium coin or button cell battery holders appeared in the form of patent no. 4487820 by the battery holder manufacturer MPD.
The electronics industry now uses many surface-mounted lithium battery holders or sockets. CR2/3A, CR1/2AA, and CR123A batteries began in camera applications but expanded into new markets like alarm systems, hand held computers and keyfobs.
Design of the battery holder requires knowledge of how and where the larger product will be used. Human factors to be considered include 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. A designer must select between a battery holder molded into the product case or made as a separate part. For many products regulations and product safety standards affect the battery holder selection.
Most current battery holders are made with polypropylene or nylon bodies rated for 80–100 °C (176–212 °F). Lithium coin cell holders are made with high temperature PBT, nylon or LCP bodies because they normally are circuit board mounted and require wave soldering at 180–240 °C (356–464 °F) or reflow soldering at 230–300 °C (446–572 °F).
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. [1] Battery contacts may be fixed contacts, flexible contacts, or some combination of the two. [2]
Fixed contacts are inexpensive but prone to loss of electrical connection. [3] Combination of fixed and flexible contacts are a better solution, but this is subject to an open circuit upon movement in the direction away from the fixed position; the spring contact compresses and allows the battery to move away from the fixed contact. A flexible contact allows for slight expansion of the cell on discharge, as internal chemicals increase in volume. Flexible contacts with multiple fingers touching the anode and cathode allow for movement in multiple directions without losing electrical connection.
Polarity, or 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. In July 2010, Microsoft said it hoped to sell its InstaLoad polarity protection technology, which allows batteries to be inserted in either orientation and still operate properly. [4] Prior methods to accomplish this were expensive or caused a passive energy drain on the battery, whereas this solution is purely mechanical and affordable to produce.
Battery types such as the 9-volt have snap-on contacts.
Battery holders for zinc-air batteries must not be completely air-tight since approximately 1 litre of air is required per ampere-hour of discharge per cell. The battery holder may include a valve integrated with the device power switch to allow air to be admitted when the device is switched on. [5]
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit. Electrodes are essential parts of batteries that can consist of a variety of materials depending on the type of battery.
A soldering iron is a hand tool used in soldering. It supplies heat to melt solder so that it can flow into the joint between two workpieces.
A printed circuit board (PCB), also called printed wiring board (PWB), is a medium used to connect or "wire" components to one another in a circuit. It takes the form of a laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with a pattern of traces, planes and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds vias, plated-through holes that allow interconnections between layers.
A breadboard, solderless breadboard, or protoboard is a construction base used to build semi-permanent prototypes of electronic circuits. Unlike a perfboard or stripboard, breadboards do not require soldering or destruction of tracks and are hence reusable. For this reason, breadboards are also popular with students and in technological education.
Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between parts of an electrical circuit, or between different electrical circuits, thereby joining them into a larger circuit.
A lithium polymer battery, or more correctly lithium-ion polymer battery, is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyte. Highly conductive semisolid (gel) polymers form this electrolyte. These batteries provide higher specific energy than other lithium battery types and are used in applications where weight is a critical feature, such as mobile devices, radio-controlled aircraft and some electric vehicles.
A flashlight (US) or electric torch (CE), usually shortened to torch, is a portable hand-held electric lamp. Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the early 2000s. A typical flashlight consists of the light source mounted in a reflector, a transparent cover to protect the light source and reflector, a battery, and a switch, all enclosed in a case.
Flexible electronics, also known as flex circuits, is a technology for assembling electronic circuits by mounting electronic devices on flexible plastic substrates, such as polyimide, PEEK or transparent conductive polyester film. Additionally, flex circuits can be screen printed silver circuits on polyester. Flexible electronic assemblies may be manufactured using identical components used for rigid printed circuit boards, allowing the board to conform to a desired shape, or to flex during its use.
In electronics and electrical engineering, a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, thereby stopping or interrupting the current. It is a sacrificial device; once a fuse has operated, it is an open circuit, and must be replaced or rewired, depending on its type.
A crocodile clip or alligator clip is a plier-like spring-tensioned metal clip with elongated, serrated jaws that is used for creating a temporary electrical connection. This simple mechanical device gets its name from the resemblance of its serrated jaws to the toothed jaws of a crocodile or alligator. It is used to clamp and grab onto a bare electrical cable to a lead on a battery or some other electrical component. The clip's tapered, serrated jaws are forced together by a spring to grip an object. A Clothespin or Kelvin clip is a special form of crocodile clip whose jaws are insulated from each other, allowing two isolated wires to connect to a single test point. This enables 4-wire measurement of circuits with very low resistances. When manufactured for electronics testing and evaluation, one jaw of the clip is typically permanently crimped or soldered to a wire, or is bent to form the inner tubular contact of a ~4 mm (0.16 in) female banana jack, enabling quick non-permanent connection between a circuit under test and laboratory equipment or to another electrical circuit. The clip is typically covered by a plastic shroud or "boot" to prevent accidental short-circuits.
The AA battery is a standard size single cell cylindrical dry battery. The IEC 60086 system calls the size R6, and ANSI C18 calls it 15. It is named UM-3 by JIS of Japan. Historically, it is known as D14, U12 – later U7, or HP7 in official documentation in the United Kingdom, or a pen cell.
A battery pack is a set of any number of (preferably) identical batteries or individual battery cells. They may be configured in a series, parallel or a mixture of both to deliver the desired voltage and current. The term battery pack is often used in reference to cordless tools, radio-controlled hobby toys, and battery electric vehicles.
Capacitors are manufactured in many styles, forms, dimensions, and from a large variety of materials. They all contain at least two electrical conductors, called plates, separated by an insulating layer (dielectric). Capacitors are widely used as parts of electrical circuits in many common electrical devices.
A button cell, watch battery, or coin battery is a small single-cell battery shaped as a squat cylinder typically 5 to 25 mm in diameter and 1 to 6 mm high – resembling a button. Stainless steel usually forms the bottom body and positive terminal of the cell; insulated from it, the metallic top cap forms the negative terminal.
Batteries provided the primary source of electricity before the development of electric generators and electrical grids around the end of the 19th century. Successive improvements in battery technology facilitated major electrical advances, from early scientific studies to the rise of telegraphs and telephones, eventually leading to portable computers, mobile phones, electric cars, and many other electrical devices.
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell.
The thin film lithium-ion battery is a form of solid-state battery. Its development is motivated by the prospect of combining the advantages of solid-state batteries with the advantages of thin-film manufacturing processes.
Film capacitors, plastic film capacitors, film dielectric capacitors, or polymer film capacitors, generically called film caps as well as power film capacitors, are electrical capacitors with an insulating plastic film as the dielectric, sometimes combined with paper as carrier of the electrodes.
InstaLoad is a patented technology developed by Microsoft which allows cylindrical batteries to function in a battery holder regardless of the batteries' polarity.
The MX-991/U Flashlight from the TL-122 military flashlight series of 1937-1944 and is a development of the MX-99/U flashlight issued in 1963. In use since the Vietnam War, the MX-991/U has been made by various contractors over the years, including GT Price, Bright Star, and Fulton Industries. MX-991/U flashlights currently issued to the United States Army and United States Marines are produced by Fulton Industries.