Batteries

There are many materials joining requirements in battery manufacture. Depending on the size, type, and capacity, these include both internal and tab-to-terminal connections, can and fill plug sealing, and external connections. Several joining options can be considered including ultrasonic , resistance, and laser welding. Ultrasonic welding is most often used to join the internal electrode battery materials which are typically constructed of thin foils of copper and aluminum. The remaining joins - including connections inside the can, and external terminal tab connections - are suited to both resistance and laser welding. The decision to use one technology or the other is determined both by the type of weld required and production requirements. Laser welding is the joining technology of choice for can and plug applications (seam sealing).

Resistance welding is a well-established joining technology - 40 years old - and has been used in the battery industry for almost as long. Since then, advances in resistance welding equipment and systems have given users improved capabilities to control different aspects of the process. The introduction of DC inverter power supplies with closed-loop control, for example, enabled welding engineers to accommodate changes in the secondary loop to address resistance. Similarly, polarity switching for capacitive discharge power supplies to enable weld nugget balancing, as well as the addition of electrode force measurement and displacement, provides manufacturers with more tools to ensure weld quality.

Laser welding was introduced to the manufacturing marketplace in the mid-1980's. As the technology has matured, and the awareness spread, laser welding has become an established process. Today, it is just another tool in the manufacturing engineer's toolbox, implemented as needed. The laser produces a high intensity beam of light that can be focused to diameters as small as 0.01". The concentration of light energy is able to melt metals rapidly, instantaneously forming a weld nugget. The non-contact process has no consumables, provides extremely tight control over the process to size the weld nugget according to requirements, and allows for implementation methods that can be geared toward the specific manufacturing requirements. Laser welding enables joining of many materials/combinations of materials, can weld thick parts, and has no limitation on proximity of weld spots.

Miyachi Unitek has extensive experience welding and marking batteries including Lithium Ion, Nickel-Metal Hydride, Lead Acid, Nickel-Cadmium and Alkaline in many different sizes: N - all sizes, AAA (LR03 / R03) - all sizes, AA (LR6 / R6) - all sizes, Sub C & C, D.

Contact us for more information or a free sample evalution.