Smaller, more powerful handheld, portable, and wearable devices depend on a new generation of battery connectors.
By Jean Thimany
While many commercial off-the-shelf battery connectors remain unchanged even after many years on the market, connector companies are creating new battery connector designs to correspond with the increasing computerization and decreasing size of many battery-powered devices. In particular, new connectors are needed to meet the evolving needs of medical devices, wearable units for military and civilians, and other lightweight, portable applications. Modern battery connector designs must accommodate these trim systems and the powerful new batteries they depend on.
Wearable devices, such as fitness monitors; medical devices including portable glucose monitors and ultrasound equipment; personal communication systems; and a host of Internet of Things (IoT) devices all depend on battery power.
The latest generation of battery connectors is ruggedized for portability, durable enough to sustain numerous insertions, able to handle high energy loads, safely contains volatile battery substances, and fits into the slim package of today’s small devices. Advanced lithium batteries have enabled devices to deliver long-lasting power while scaling down in size.
“When it comes to battery connectors, most companies are looking for a different height or for a different size,” said Tom Anderson, connector product manager at AVX Corporation. “While people will usually find something close to what they need, they really want something a little different from that.”
AVX’s 9155-800 Series vertical-mate, 2mm-pitch battery connectors are designed to prevent end-user damage to the contacts in electronic devices with pluggable modules that vertically mate with a base unit. The company knew designers would welcome the vertical-mating connectors.
“Think, for example, of when you have to replace a battery in a cellphone. Those are small connectors, and when you put the battery pack in, you have to put it in an angle and rotate it down. If you pushed it straight in, you’d damage the contacts,” Anderson said. “Most of our right-angle battery connectors are made to mate horizontally or at a slight angle.”
Electronic devices with removable battery modules designed to be replaced by users — which range from consumer devices like smartphones and tablets to industrial electronics like rechargeable walkie-talkies — often experience connector damage resulting from improper module removal or insertion.
Many portable industrial and medical devices are designed to accept pluggable or disposable modules. In these devices, traditional compression- or battery-style connectors often require the initial engagement to be at a slight angle, then rotated into position. Vertical-mate connectors provide a foolproof, error-free mating engagement without contact stubbing or damage.
AVX’s 9155-700 Series 2mm-pitch, right-angle, board-to-board battery connectors are designed to provide miniaturized, mechanically stable, high-integrity connections in harsh-environment applications. Handheld and portable devices that require dock or cradle charging, patient monitoring devices and other portable medical electronics, industrial programming modules, point of sale terminals, and IoT devices are all subject to high shock and vibration, said Anderson.
“Many portable electronic devices are designed to accept right-angle modules, and these devices are especially subject to the overwhelming trend toward miniaturization,” he said. “So, we designed our new 9155-700 Series right-angle battery connectors with a minimal 2mm pitch and 4mm connector height while maintaining the 2A rating of our larger right-angle battery connectors to help engineers respond to continual requests to minimize size.”
Another factor impacting connector battery design is current levels. Materials and design must correspond with the amperages. Alloys such as phosphor bronze and beryllium copper are increasingly employed in battery connectors. Companies like SMK are offering connectors with increasing numbers of pins. The company’s FB-9 Series features a power terminal rated at 15A and a space-saving design suited to small devices.
The Multi-Direction Interconnection (MDI) System from TE Connectivity is a high-density interconnect with six-position receptacles and headers featuring contacts on a 2mm centerline. These connectors are available in right-angle or vertical-mount headers with left, right, or keyless polarization. The system is designed to permit mating and unmating at any angle between 0° and 90°.
Meritec offers a variety of vertical push-in, sliding, and push-down battery connectors designed for connecting a removable battery pack to a portable device. The company’s four-circuit, 3.5mm-pitch sliding battery connectors are rated for a maximum current of 2A and maximum voltage of 15VDC, and are designed to withstand 5,000 mating cycles.
The traditional button battery holder still has its place, but even this venerable design is getting an upgrade. LOTES offers button battery holders with right-angle or vertical orientation options in heights ranging from 5.1mm to 8.5mm to give customers flexibility.
Spring-loaded or pogo pin battery connectors are typically used in base charging units for rechargeable devices such as phones, bar-code scanners, and medical devices. They can also serve as a surface-to-surface contact between circuit boards and in spring probe units for testing equipment. Companies like Mill-Max, ECT, and Yokowo offer pogo connectors with a variety of features and contact metals, including high-current, waterproof, and easy assembly options. These connectors are designed to withstand multiple use cycles while maintaining a consistent current.
New battery connector designs are proliferating, and many companies also offer custom design capabilities so that a new system design isn’t constrained by the size or position of the battery connector. While the devices we use continue to scale down in size, they make no sacrifices in terms of power, thanks to long-lasting batteries securely held by efficiently designed battery connectors.
Jean Thilmany is a Twin Cities-based writer who covers engineering, technology, and science topics.