A smart battery or a smart battery pack is a rechargeable

battery pack A battery pack is a set of any number of (preferably) identical batteries or individual battery cells. They may be configured in a series, parallel or a mixture of both to deliver the desired voltage, capacity, or power density. The term battery ...

with a built-in battery management system (BMS), usually designed for use in a

portable computer A portable computer is a computer designed to be easily moved from one place to another and included a display and keyboard together, with a single plug, much like later desktop computers called '' all-in-ones'' (AIO), that integrate the sy ...

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 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 ...

PMBus The Power Management Bus (PMBus) is a variant of the System Management Bus (SMBus) which is targeted at digital management of power supplies. Like SMBus, it is a relatively slow speed two wire communications protocol based on I²C. Unlike either ...

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 RS-485, also known as TIA-485(-A) or EIA-485, is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. The s ...

, and

Local Interconnect Network LIN (Local Interconnect Network) is a serial network protocol used for communication between components in vehicles. It is a single wire, serial network protocol that supports communications up to 19.2 Kbit/s at a bus length of 40 meters. The need ...

. 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 Smart Battery System (SBS) is a specification for managing a smart battery, usually for a portable computer. It allows operating systems to perform power management operations via a smart battery charger based on remaining estimated run times by ...

MIPI BIF
and many ad-hoc specifications.

Charging

A smart battery charger is mainly a switch mode power supply (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 A Controller Area Network (CAN bus) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer. It is a message-based protocol, designed originally for mu ...

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

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 e ...

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

Hardware

Smart battery controller

integrated circuits An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...

are available. For example,

Linear Technology Linear Technology Corporation was an American semiconductor company that designed, manufactured and marketed high performance analog integrated circuits. Applications for the company's products included telecommunications, cellular telephones, ne ...

manufactures the LTC4100 and the LTC4101 Smart Battery System-compatible products.

Microchip Technology Microchip Technology Inc. is a publicly-listed American corporation that manufactures microcontroller, mixed-signal, analog and Flash-IP integrated circuits. Its products include microcontrollers ( PIC, dsPIC, AVR and SAM), Serial EEPROM ...

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