Last time, I introduced the S-82B1B series, Battery Protection IC with the Power-saving function, which protects batteries against deep discharge by stopping discharge from the battery pack and reducing current consumption of the protection circuit. The Power-saving function of the S-82B1B prolongs time from state of 30% charged to power 0 even with the small battery such as 25mAh. When you use S-82B1B series, run time is 17 years and it is 30 times longer than ABLIC’s predecessor, S-8240A series, and 60 times longer than a competitor’s product (See Fig.1).
As I described in the previous article, after battery power become 0 and further discharging, it reaches deep discharge. What is happening inside the battery after deep discharge?
Inside the lithium-ion batteries, after reaching deep discharge, the potential of the negative electrode is rebounded. And it increases over the dissolution and precipitation potential of copper, the copper foil around the negative electrode dissolves into electrolysis solution as ionic substances and the negative electrode is damaged (See Fig.2-1). When the ions in electrolysis solution move towards the positive electrode, copper precipitates on it (See Fig.2-2) and internal short occurs due to the copper precipitation (See Fig.2-3).
If you recharge the battery, it may cause an exothermal reaction and sometimes an accident of fire.
Thus, the battery has been deteriorated which is related to the safety of the battery after deep discharge. And the safety of the product is directly impacted by its battery’s deterioration.
By the way, what kind of products use small li-ion batteries which are target market of S-82B1B series?
Fig.3 shows variety of the products that use relatively small batteries. They are sorted by field of the application and power of the battery from tens of milliampere per hour (mAh) to 800mAh. These data are from our market research reports. There are mini drones, drive recorders, cameras, small smartphones.
And the batteries under 100mAh are all equipped in wearable devices.
Wearable devices, as the name implies, used directly on the human body such as our wrists and ears for a long time. If wearable products become widely used for the purpose of health care and monitoring against a background of super-aging society in the future, it will be expected to run constantly and improve the safety and security. High safety is also required for the battery.
The S-82B1B series responds to these market demands and extends battery run time practically with power-saving function. We have to admit to prepare additional resources for inspection and so on to adopt the Power-saving function. But it enhances entire safety of the product. In that sense, the S-82B1B series is no longer just a “Battery Protection IC”. It might be the “Safety IC” supporting safety and security of the entire product (See Fig.4).
- [Application] ICs ideal for Smart Watches and Smart Bands
- [Product information/Datasheet] Battery Protection IC with Power-saving Function for 1-Cell Pack S-82B1B