Smart Battery System (SMBus)

How does a smart battery work?

Background and Challenges

The battery has the inherent problem of not being able to communicate with the user. Neither weight, color, nor size provide any indication of the battery's state of charge (SoC) and state of health (SoH).

There are several types of "smart" batteries, each with varying degrees of complexity and cost. The most basic "smart" battery may contain only a chip responsible for configuring the charger to the correct charging algorithm.

Defining a 'smart' battery remains a subject of different interpretations among organizations and manufacturers. As per the SBS forum, a 'smart' battery must be capable of delivering State of Charge (SoC) indications. Currently, this technology is being produced by multiple manufacturers, utilizing systems that range from the single-wire to the two-wire system and the System Management Bus (SMBus).

The single-wire system enables data communication through a single wire. This battery employs three wires, including the positive and negative battery terminals, in addition to a data terminal that doubles as the clock information provider.

For safety reasons, many battery manufacturers include a dedicated wire for temperature sensing. The single-wire system stores the battery code and monitors various battery metrics such as temperature, voltage, current, and state of charge (SoC).

Due to its cost-effectiveness, the single-wire system has gained acceptance in the market for high-end two-way radios, camcorders, and portable computing devices. However, the lack of a standardized form factor in most single-wire systems and the inability to conduct uniform measurements of their State of Health (SoH) present challenges for a universal charger concept.

SMBus stands out as the most comprehensive of all systems, representing a significant collaborative effort within the electronics industry to establish a unified communications protocol and data set. The Duracell/Intel SBS currently in use was standardized in 1993.

It operates as a two-wire interface system with separate lines for data and clock. This setup is conducive to standardized state of charge and state of health measurements.

The purpose of the SMBus battery is to transfer charge control from the charger to the battery. In a true SMBus system, the battery is the master and the charger is the slave that must follow the battery's instructions.

The "smart" battery has certain disadvantages, one of which is its higher cost. An SMBus battery is about 25% more expensive than its 'dumb' counterpart. It also adds complexity to chargers, as most chargers designed for smart batteries are hybrid and also compatible with nonsmart batteries.

Another challenge with the SMBus battery is non-compliance. Unlike other tightly regulated standards, the SMBus protocol allows for certain variations. This flexibility can lead to compatibility issues with existing chargers, emphasizing the need to test the SMBus battery for compatibility before use.

Solution

Jarltech is dedicated to helping other companies develop their products. Our experienced engineers have a wealth of knowledge in various fields and have successfully developed products ranging from laser range finders to safety switches.

We are currently dedicated to helping other companies design their power solutions, including batteries, power supplies, and DC-DC converters. It makes sense for you to focus on your expertise while we focus on ours.

We also offer a variety of readily available products to accelerate your product development. Our expertise extends to custom, semi-custom and off-the-shelf solutions for power supplies, battery chargers, UPS and battery backups. In addition, we help our customers certify their batteries to BSMI and MSDS standards.

We specialize in helping our customers design custom battery pack products that are highly cost effective, environmentally friendly, and exceed all specified requirements.

Our selection of batteries and custom battery packs allows us to work with our customers and their engineering teams to meet the power requirements of their end products. Our goal is to exceed your specifications while staying within your budget.

We not only design products, but we also manufacture them globally. This not only benefits our customers, but also fosters strong, long-term relationships with both our customers and our manufacturing partners.

Our products are both cost effective and environmentally friendly, with custom designs tailored to your specifications. We pride ourselves on our easy-to-work-with approach and our ability to quickly develop custom products.