Thin film batteries, in the simplest terms, are batteries designed to be a thinner version of a typical battery with as few tradeoffs as possible. The increased interest in this form factor has come alongside the rapid growth of the Internet of Things as well as the emergence of wearable electronics. Thin film batteries enable new unique devices, but they come with a set of challenges that must be considered.
Pros of Thin Film Batteries
Size and Shape
The reduced thickness of thin film batteries make them a unique solution to many power source problems. With the rapid growth of wearable technology and the Internet of Things, devices are getting smaller. These smaller devices need smaller batteries, which has resulted in more interest in thin film batteries. They are couple of millimeters down to tenths of millimeters thick, with a thin flat shape. The thinner and smaller the battery, the easier it is to craft the device to a manageable size. With less space devoted to the battery, the designers and engineers have more options in product development.
Specific products stand to benefit from the advantages of thin film batteries. Wearable devices, for example, can benefit from thin film batteries because of their inherent need for thin power storage units. A thin film battery can fit in a smart watch, a shoe, or a vest, enabling wearable electronic applications.
The flat form factor of thin film batteries enables their incorporation into labels and patches to be applied on various surfaces. Radio Frequency Identification (RFID) devices which emit data on their own are one application that can benefit from a thin film battery. Businesses use RFID technology in their logistics to track the shipping of important products as are transported from one location to another. These labels can also monitor and transmit data like the temperature of the label or send out data when the label passes certain security checkpoints.
Powered patches that apply directly to the people’s skin, such as drug patches or Transcutaneous Electrical Nerve Stimulation (TENS) devices, are another application that can benefit from thin film batteries. Each of these devices require battery power to be built in, and thin film batteries allow for the design to be less bulky and more concealable.
While any battery can be customized, thin film batteries provide a unique set of options to craft devices alongside. Their unique flat shape and small size present more options for a developer trying to fit a battery into their plan. Thin film batteries can fit into narrower spaces than conventional power sources which makes them a versatile solution to the issue of power storage in any device that should be thin and compact.
Thin film batteries have another unique characteristic: they can be flexible. With thin and flexible batteries that can be tailored to a developer’s needs, thin film batteries present themselves as a battery type with a lot to offer. In the medical field, wearable devices engineered with a thin film battery form factor to reduce their size are a significant step towards furthering network integration while increasing comfort during use.
Cons of Thin Film Batteries
Design and Production
The thin film battery does not come without challenges to overcome. The thinner makeup of the battery presents an increased risk of failure. A well-engineered battery will not present any health or safety risks when a dramatic failure occurs, but thin film battery limits must be understood and accommodated.
With much thinner electrodes, thin film batteries generally have less duration than a typical battery would. However, if the thin film battery needs to provide greater operational life, the engineering of the electrodes can be altered to increase capacity at the cost of reducing the current rate capability for example. A significant challenge that comes with a thin film battery is balancing the battery capacity (duration), the current rate, and the battery volume. Of these three, volume typically presents the greatest challenges.
With this in mind, it is important for designers who want to use thin film batteries to understand what their priorities are, going into the battery design. If they do not, there may be a cascading effect eventually requiring a complete recalculation and overhaul of the entire device design.
Generally speaking, thin film batteries are not broadly available on a commercial level, but conventional batteries are in large volumes. Additionally, the cost of typical batteries is much lower than the cost of thin film batteries. This is mostly due to the need for specificity in thin film battery design and the fact that thin film batteries do not benefit from the mature production lines in place for conventional batteries. Thin film batteries could, however, eventually attain a low production cost as production volume scales up.
While there are several challenges that come with utilizing thin film batteries, these issues can be overcome with a focused plan, realistic expectations, and a strong relationship between the device developers and the battery developers. Under these conditions, the device developers can take advantage of the relatively untapped benefits of thin film batteries. According to market research from Technavio, the compound annual growth rate of the global thin film battery market will be 45% by 2019. The market for thin film batteries is rapidly expanding, and if you can offset their limitations, they are an excellent option for any future device.