In recent years, due to the rapid development of lithium batteries, many portable products use voltage measurements to estimate the residual capacity of batteries, but the relationship between battery voltage and residual capacity will change with discharge rate, temperature and aging degree of batteries. The maximum error rate is 50%. Due to the increasing demand for products with longer service time, more precise solutions are needed in design. Measuring the charge or consumption of batteries by using smart power meter IC will provide more accurate estimation of battery power in a wide range of application power levels.。
1. Design requirements of intelligent battery for notebook B-mode supersonic machine:
According to the requirements and specifications of customers, the design of intelligent battery pack for laptop B-mode supersonic computer matched with the host computer and the integration of intelligent meter with communication protocol, lithium battery and safety protection performance into your solution can achieve information sharing between the intelligent battery pack and the host computer, and ultimately achieve a reasonable, efficient and safe battery manager. Case. In the whole design process, to ensure the safety of batteries, batteries and the whole system is the premise, and to meet the corresponding design regulations and certification regulations is the first choice. At the same time, in order to ensure the safety and reliability of lithium batteries, multi-layer protection should be adopted to prevent the lithium batteries from being overcharged, overdischarged or short-circuit damaged.
2. Design scheme of intelligent battery for notebook B-mode supersonic machine:
_18650 lithium ion core/18650 Li-ion cell (NCR 18650A Panasonic).
_Battery Specification: NCR 18650A-4S2P-6200mAh-14.4V
_Protective board (PCM): The main protection circuit is designed for rechargeable batteries (generally referred to as lithium batteries). Due to the chemical characteristics of lithium batteries, it is necessary to provide over-charging, over-discharge, short circuit, over-current and over-temperature protection functions. In order to avoid the danger of combustion, explosion and so on.
Protection IC: BQ29330DBT is the main protection function chip of the design scheme, which monitors the functions of overcharge, overdischarge, overcurrent and short circuit on-line. Make the core work in a safe, stable and efficient range.
Fuse: T6D is mainly designed for secondary protection function. Fuse in battery products can prevent high temperature discharge and unsafe high current (self-burning can not be restored when the temperature is higher than 139 degrees).
_Field Effect Transistor (MOSFET): Two MOSFET transistors of the same type, AON6404, play a switching role in the protection circuit, and never increase or decrease the voltage at both ends of the load to ensure voltage stability.
Power Management Control Chip (BQ20z70DBT): A fully functional power detector with an analog-to-digital converter (ADC) for measuring voltage and temperature and an analog-to-digital converter for measuring current and charging sensing. The power meter has a microprocessor responsible for executing the power meter to provide information such as Remaining State of Capacity. The BQ20z70DBT product also provides Run Time to Empty. The host computer can inquire these information from the power meter at any time and inform the user of the battery information. The electric quantity detector is very convenient to use. Let the user grasp the battery power at any time.
Battery pack effect after packaging (rubber case):