Lithium battery/battery pack metering and protection circuit based on current segment detection technology

Abstract

The invention relates to a lithium battery / battery pack measuring and protecting method based on a current subsection detecting technique, which realizes intelligent controls of electric quantity detection for batteries, charge and discharge control, overcurrent / overvoltage protection, short circuit protection, and the like, and adopts a micro-control unit (MCU) mode to realize precision measuring control and intelligent management. The MCU transmits battery sampling voltage and current data to an analog-to-digital converter (ADC) to carry out quantitative analysis; the quantitative data and optimization data prestored in the MCU are compared; and the minimus information is fed back to a switch controlled by an analog front end (AFE) module to precisely control parameters of charge and discharge current, voltage, and the like. The detection mode of the MCU for the charge and discharge current of the batteries adopts the subsection detecting technique, wherein the charge and discharge current of the batteries are converted into digital signals by a voltage-mode converting circuit and a current-mode comparator, and the digital signals are sent to a central processing unit (CPU) in the MCU to carry out analysis and battery control. The invention improves the measuring precision, reduces the cost of design and production of chips and reduces the power consumption of the chips.

Description

technical field [0001] The invention belongs to the current measurement and protection of a rechargeable battery or a battery pack, in particular to a lithium battery / battery pack measurement and protection circuit based on current segment detection technology. Background technique [0002] Rechargeable batteries are reusable batteries, usually lead-acid, nickel-cadmium, nickel-metal hydride, lithium-ion, fuel cells, etc. In recent years, with the wide application of portable products, more and more products use lithium batteries as their main power supply. Lithium batteries have the following characteristics: small size, high energy density, no memory effect, high cycle life, high voltage battery, self- Low discharge rate, environmental protection and no pollution, etc., especially in the power supply of notebook computers, its excellent high energy advantage is brought into full play. However, due to the high energy density and unique chemical characteristics, there are a...

AI Technical Summary

Problems solved by technology

However, when the charging and discharging current is in milliamps, the converted voltage signal is on the order of several microvolts, which is a very weak signal, and the noise in the circuit will lead to inaccurate detection of such a current

At the same time, the charging and discharging current of the lithium battery pack may reach several amperes, tens of amperes or even higher, such as in applications such as electric vehicles, so that its dynamic range will reach 10 4 ~10 5 , which will require an analog-to-digital conversion precision higher than 14 bits, which greatly increases the complexity of the hardware and the implementation cost of the circuit

[0007] The measurement of charging and discharging current must be accurate, otherwise, the capacity state of the battery cannot be calculated correctly: when discharging, it may cause over-discharging, which may cause battery failure; Cause battery failure, even cause fire and explosion

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