CN202127240U - A lithium battery charge and discharge overcharge and overdischarge protection circuit - Google Patents

Abstract

The utility model discloses an overcharging and over-discharging protection circuit of a lithium battery, which comprises a power supply circuit module, a switch circuit module, a lithium battery and a microcontroller microprogrammed control unit (MCU), wherein the power supply circuit module, the switch circuit module, the lithium battery and the microcontroller MCU are electrically connected in sequence. The microcontroller MCU is connected with the switch circuit module, and an over-voltage/over-current/short circuit protection circuit module is connected with the lithium battery. The overcharging and over-discharging protection circuit of the lithium battery is simple in structure and stable in performance, and can control overcharging and over-discharging protection of the lithium battery through the intelligent MCU.

Description

A lithium battery charge and discharge overcharge and overdischarge protection circuit

technical field

The utility model relates to a lithium battery charging circuit, in particular to a lithium battery charge and discharge overcharge and overdischarge protection circuit.

Background technique

With the development of science and technology, mobile electronic devices are more and more widely used, and mobile electronic devices generally use mobile batteries as power sources. Existing mobile batteries generally use rechargeable lithium batteries, because they can be repeatedly charged and discharged without frequent replacement, and are now widely used in the field of solar lamps. However, when a lithium battery is charging and discharging, it is easy to cause the charging power to be difficult to control. Overcharging will lead to a change in the structure of the positive electrode material and a loss of capacity. It will decompose and release oxygen and violently oxidize the electrolyte, resulting in combustion and explosion. decline, life expectancy is reduced. Therefore, setting a charging and over-discharging protection circuit in the battery charging and discharging circuit of a lithium battery can effectively improve this problem, but almost all existing charging and discharging protection circuits have the problems of complex structure and poor charging and discharging protection effect.

Utility model content

The technical problem to be solved by the utility model is to provide a lithium battery charge and discharge overcharge and overdischarge protection circuit to solve the problem of lithium battery charge and discharge overcharge and overdischarge, and has a simple structure and good charge and discharge protection effect.

The technical scheme of the utility model is:

A lithium battery charge and discharge overcharge and overdischarge protection circuit, which includes a charging power supply circuit module, a switch circuit module, a lithium battery and a microcontroller MCU connected in sequence, the microcontroller MCU is connected to the switch circuit module, and the The lithium battery is connected with an overvoltage/overcurrent/short circuit protection circuit module.

The charging power supply circuit module is connected with a battery voltage/current detection circuit module, and the battery voltage/current control module is connected with the microcontroller MCU.

The over-voltage/over-current/short-circuit protection circuit module adopts chip fuses.

Advantage of the utility model:

(1) The lithium battery is connected to the microcontroller MCU, and the control of the charge and discharge of the lithium battery is controlled by the MCU. The structure is simple, and the charge and discharge protection control effect is good;

(2) The overvoltage/overcurrent/short circuit protection circuit is connected in series on the lithium battery to ensure that when the microcontroller MCU is abnormal and cannot be controlled, the overvoltage/overcurrent/short circuit protection circuit module realizes the discharge overcurrent protection of the lithium battery , Battery over-discharge protection, charging over-current protection and charging over-voltage protection;

(3) A switching circuit module is set between the charging power circuit module and the lithium battery, and the switching circuit module is controlled by the microcontroller MCU to play the role of switching the charging circuit of the lithium battery, so as to avoid excessive damage to the lithium battery by the charging power circuit module. charging phenomenon.

Description of drawings

Fig. 1 is the schematic circuit diagram of the utility model.

Detailed ways

See Fig. 1, a kind of lithium battery charging and discharging overcharging and overdischarging protection circuit, comprises the charging power supply circuit module 1, switch circuit module 2, lithium battery 3 and microcontroller MCU 4 connected in sequence, connected with the charging power supply circuit module 1 Battery voltage/current detection circuit module 5 and overvoltage/overcurrent/short circuit protection circuit module 6 connected with lithium battery 3, switch circuit module 2, battery voltage/current control module 5 are all connected with microcontroller MCU 4.

Charging power supply circuit module 1 adopts constant voltage/constant current circuit, and the circuit adopts PWM switch to control integrated IC, and provides charging power for lithium battery 3 through BUCK circuit topology; /D conversion circuit to detect the voltage and current of the battery in real time; the overvoltage/overcurrent/short circuit protection circuit module uses a chip fuse. When the microcontroller MCU4 is abnormal and cannot be controlled, the overvoltage/overcurrent/short circuit protection circuit The module 6 implements discharge overcurrent protection, battery overdischarge protection, charging overcurrent protection and charging overvoltage protection of the lithium battery 3 .

When charging, the microcontroller MCU 4 controls the switch circuit module 2 to protect the overcharge, and when discharging, the microcontroller MCU 4 controls the lithium battery 3 to realize overdischarge protection. the

The parameters and functions of the lithium battery charge and discharge overcharge and overdischarge protection circuit:

Lithium battery discharge current during standby <22μA Discharge cut-off voltage 7V End-of-discharge voltage (single unit) 3.5V Maximum discharge current 500mA Discharge overcurrent protection Chip fuse 2A Battery over-discharge protection Chip fuse 2A Pre-charge current/terminate charge current 50mA Precharge voltage threshold (single unit) 2.75V Constant current charging current 500mA Constant voltage charging voltage 8.4V Constant voltage charging voltage (single unit) 4.2V Two batteries guarantee charging consistency Difference<0.1V Overshoot protection voltage (single unit) 4.25V Charging overcurrent protection Chip fuse 2A Charging overvoltage protection Chip fuse 2A Overcharge Protection MCU program Over temperature protection 60℃ Battery external short circuit protection Chip fuse 2A

Claims (3)

1. a lithium battery charge and discharge overcharge and overdischarge protection circuit is characterized in that: it includes a charging power supply circuit module, a switch circuit module, a lithium battery and a microcontroller MCU connected successively, and the microcontroller MCU and the switch The circuit module is connected, and the lithium battery is connected with an overvoltage/overcurrent/short circuit protection circuit module. 2. A lithium battery charge and discharge overcharge and overdischarge protection circuit according to claim 1, characterized in that: said charging power supply circuit module is connected with a battery voltage/current detection circuit module, and the battery voltage/current control The module is connected with the said microcontroller MCU. 3. A lithium battery charging and discharging overcharging and overdischarging protection circuit according to claim 1, characterized in that: said overvoltage/overcurrent/short circuit protection circuit module is a chip fuse.