Lithium battery protection circuit
By using the protection chip R5438L305BA in the lithium battery protection circuit, the battery voltage difference is collected to control the fuse's on/off state, thus solving the problems of overcharging and over-discharging of lithium batteries and improving safety and service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU TAIDING INTELLIGENT TECH CO LTD
- Filing Date
- 2025-06-26
- Publication Date
- 2026-07-03
AI Technical Summary
Lithium batteries lack effective overcharge and over-discharge protection during charging and discharging, resulting in poor safety.
The protection chip R5438L305BA is used to control the opening and closing of the three-terminal fuse by collecting the voltage difference between the positive and negative terminals of the lithium battery, thereby achieving overcharge and over-discharge protection.
It improves the safety of lithium batteries, prevents overcharging and over-discharging, and extends their service life.
Smart Images
Figure CN224459239U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of lithium-ion battery technology, and in particular to a lithium battery protection circuit. Background Technology
[0002] Lithium batteries have advantages such as high energy density, long lifespan, high rated voltage, high power handling capacity, low self-discharge rate, light weight, and strong adaptability to high and low temperatures. However, they also have disadvantages such as poor safety and the need for protection circuits to prevent overcharging and over-discharging. Utility Model Content
[0003] The purpose of this invention is to provide a lithium battery protection circuit that provides overcharge and over-discharge protection.
[0004] The technical solution of this utility model is:
[0005] The lithium battery protection circuit includes a protection chip R5438L305BA. The positive and negative terminals B+ and B- of the lithium battery are connected to the positive and negative charging terminals P+ and P- for charging, respectively. A three-terminal fuse F1 is connected in series between the positive charging terminal P+ and the positive terminal B+ of the lithium battery. The voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected to the positive and negative terminals B+ and B- of the lithium battery, respectively. The output pin COUT of the protection chip R5438L305BA is connected to the control terminal SCF1 that controls the three-terminal fuse F1.
[0006] Preferably, the output pin COUT of the protection chip R5438L305BA is connected to the control terminal SCF1 of the three-terminal fuse F1 via the switching transistor Q7.
[0007] Preferably, the voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected to the positive and negative terminals B+ and B- of the lithium battery through resistors R22 and R19, respectively.
[0008] Preferably, the voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected by capacitor C12, and the voltage acquisition pin VC2 is grounded by capacitor C13.
[0009] Preferably, the power supply pin VDD of the protection chip R5438L305BA is powered by the positive and negative terminals B+ of the lithium battery through resistor R23, and the power supply pin VDD is also grounded through capacitor C11.
[0010] The advantages of this utility model are:
[0011] The lithium battery protection circuit of this utility model uses the protection chip R5438L305BA to collect the positive and negative B+ and B- voltages of the lithium battery. Based on the voltage difference, the charging and discharging state of the battery is determined, and then the charging and discharging is controlled by the three-terminal fuse F1 to realize overcharge and over-discharge protection and improve safety. Attached Figure Description
[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0013] Figure 1 This is a schematic diagram of the lithium battery protection circuit of this utility model. Detailed Implementation
[0014] like Figure 1 As shown, the lithium battery protection circuit of this utility model includes a protection chip R5438L305BA. The positive and negative terminals B+ and B- of the lithium battery are connected to the positive and negative charging terminals P+ and P- for charging, respectively. A three-terminal fuse F1 is connected in series between the positive charging terminal P+ and the positive terminal B+ of the lithium battery. The voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected to the positive and negative terminals B+ and B- of the lithium battery, respectively. The output pin COUT of the protection chip R5438L305BA is connected to the control terminal SCF1 that controls the three-terminal fuse F1.
[0015] The power supply pin VDD of the protection chip R5438L305BA is connected to the positive and negative terminals B+ of the lithium battery through resistor R23. The power supply pin VDD is also grounded through capacitor C11.
[0016] The voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected to the positive and negative terminals B+ and B- of the lithium battery through resistors R22 and R19, respectively. The voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected through capacitor C12, and the voltage acquisition pin VC2 is grounded through capacitor C13.
[0017] The output pin COUT of the protection chip R5438L305BA is connected to the control terminal SCF1 of the three-terminal fuse F1 via the switching transistor Q7. The switching transistor Q7 is a MOSFET, with its source grounded, its drain connected to the control terminal SCF1, and its gate connected to the output pin COUT of the protection chip R5438L305BA via resistor R20. There are also resistors R21 and capacitor C14 between the source and the gate.
[0018] When the voltage difference between the voltage acquisition pins VC1 and VC2 exceeds the charging threshold, the output pin COUT of the protection chip R5438L305BA outputs a high level, turning on the switching transistor Q7, thus switching the fuse on and off and stopping charging. When the voltage difference between the voltage acquisition pins VC1 and VC2 is less than the discharging threshold, discharging stops.
[0019] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All modifications made in accordance with the spirit and essence of the main technical solution of this utility model should be included within the scope of protection of this utility model.
Claims
1. A lithium battery protection circuit, characterized in that, The system includes a protection chip R5438L305BA. The positive and negative terminals B+ and B- of the lithium battery are connected to the positive and negative charging terminals P+ and P- for charging, respectively. A three-terminal fuse F1 is connected in series between the positive charging terminal P+ and the positive terminal B+ of the lithium battery. The voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected to the positive and negative terminals B+ and B- of the lithium battery, respectively. The output pin COUT of the protection chip R5438L305BA is connected to the control terminal SCF1 that controls the three-terminal fuse F1.
2. The lithium battery protection circuit of claim 1, wherein, The output pin COUT of the protection chip R5438L305BA is connected to the control terminal SCF1 of the three-terminal fuse F1 via the switching transistor Q7.
3. The lithium battery protection circuit of claim 2, wherein, The voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected to the positive and negative terminals B+ and B- of the lithium battery through resistors R22 and R19, respectively.
4. The lithium battery protection circuit of claim 3, wherein, The voltage acquisition pins VC1 and VC2 of the protection chip R5438L305BA are connected through capacitor C12, and the voltage acquisition pin VC2 is grounded through capacitor C13.
5. The lithium battery protection circuit of claim 1, wherein, The power supply pin VDD of the protection chip R5438L305BA is connected to the positive and negative terminals B+ of the lithium battery through resistor R23. The power supply pin VDD is also grounded through capacitor C11.