A smart battery or a smart battery pack is a rechargeable battery pack with a built-in battery management system (BMS), usually designed for use in a portable computer such as a

laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...

. In addition to the usual positive and negative terminals, a smart battery has two or more terminals to connect to the BMS; typically the negative terminal is also used as BMS "ground". BMS interface examples are: SMBus, PMBus,

EIA-232 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such ...

, EIA-485, and Local Interconnect Network. Internally, a smart battery can measure voltage and current, and deduce charge level and SoH (State of Health) parameters, indicating the state of the cells. Externally, a smart battery can communicate with a smart battery charger and a "smart energy user" via the bus interface. A smart battery can demand that the charging stop, request charging, or demand that the smart energy user stop using power from this battery. There are standard specifications for smart batteries: Smart Battery System
MIPI BIF
and many ad-hoc specifications.

Charging

A smart battery charger is mainly a

switch mode power supply A switched-mode power supply (switching-mode power supply, switch-mode power supply, switched power supply, SMPS, or switcher) is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently. Like ...

(also known as high frequency charger) that has the ability to communicate with a smart battery pack's battery management system (BMS) in order to control and monitor the charging process. This communication may be by a standard bus such as CAN bus in automobiles or

System Management Bus The System Management Bus (abbreviated to SMBus or SMB) is a single-ended simple two-wire bus for the purpose of lightweight communication. Most commonly it is found in computer motherboards for communication with the power source for ON/OFF instru ...

(SMBus) in computers. The charge process is controlled by the BMS and not by the charger, thus increasing security in the system. Not all chargers have this type of communication which is commonly used for lithium batteries. Besides the usual plus (positive) and minus (negative) terminals, a smart battery charger also has multiple terminals to connect to the smart battery pack's BMS. The Smart Battery System standard is commonly used to define this connection, which includes the

data bus In computer architecture, a bus (shortened form of the Latin '' omnibus'', and historically also called data highway or databus) is a communication system that transfers data between components inside a computer, or between computers. This ex ...

and the communications protocol between the charger and battery. There are other ''ad-hoc'' specifications also used.

Hardware

Smart battery controller integrated circuits are available. For example, Linear Technology manufactures the LTC4100 and the LTC4101 Smart Battery System-compatible products. Microchip Technology provides an application note for a smart battery charger based on the PIC16C73.direct link
The PIC16C73 source code is available for this application.

References

{{reflist Smart devices Rechargeable batteries Battery charging

Charging

Hardware

See also

References