Implementation circuit for lithium battery charging protection

Abstract

The utility model discloses an implementation circuit for lithium battery charging protection. The implementation circuit comprises a voltage anode, a first divider resistor, a grid pull-up resistor, a second divider resistor, a battery body, an MOS effect transistor and a grounding end, one end of the battery body is connected in series with an MOS effect transistor, a source electrode of the MOS effect transistor is electrically connected with a negative electrode of the battery body, and a drain electrode of the MOS effect transistor is electrically connected with a grounding end; the first divider resistor is electrically connected with a second divider resistor, the first divider resistor and the second divider resistor are connected in series, and the second divider resistor is electrically connected to the grounding end; according to the utility model, the lithium battery charging protection circuit is designed, and when the charging voltage exceeds 4.2 V, the MOS is turned off to stop charging, so that the battery is prevented from being overcharged, the risk of spontaneous combustion rupture caused by decomposition of electrolyte due to temperature rise of the battery caused by overcharging of the battery is avoided, and the safety performance of charging of the lithium battery is improved; and meanwhile, the problem of durability reduction caused by battery degradation is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a circuit for realizing charging protection of lithium batteries. Background Art

[0002] In recent years, more and more devices use lithium batteries as the main power source. Lithium batteries have the advantages of small size, high energy density, no memory effect, long cycle life, high voltage and low self-discharge rate. However, the existing lithium batteries lack a charging protection circuit during the charging process, which can easily lead to overcharging of the lithium batteries. In the overcharged state, the battery temperature rises, the electrolyte decomposes to produce gas, and the internal pressure rises, causing natural or rupture, posing a safety hazard. In addition, the decomposition of the electrolyte will cause the battery to deteriorate, reduce durability, and reduce the number of recharges. Utility Model Content

[0003] The purpose of the utility model is to provide a circuit for realizing charging protection of a lithium battery to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the utility model provides the following technical solutions: a circuit for implementing lithium battery charging protection, comprising a battery body, one end of the battery body being connected in series with a MOS effect tube, and the source of the MOS effect tube being electrically connected to the negative electrode of the battery body, and the drain of the MOS effect tube being electrically connected to a ground terminal.

[0005] Preferably, the positive electrode of the battery body is electrically connected to a positive voltage electrode.

[0006] Preferably, a first voltage-dividing resistor is electrically connected to the voltage positive electrode.

[0007] Preferably, a second voltage-dividing resistor is electrically connected to the first voltage-dividing resistor, and the first voltage-dividing resistor and the second voltage-dividing resistor are connected in series with each other, and the second voltage-dividing resistor is electrically connected to a ground terminal.

[0008] Preferably, a gate pull-up resistor is electrically connected to the positive voltage electrode.

[0009] Preferably, the gate pull-up resistor is electrically connected to the gate of the MOS effect transistor.

[0010] Preferably, a voltage-stabilizing diode is electrically connected to the gate pull-up resistor, and the voltage-stabilizing diode is electrically connected to the gate of the MOS effect transistor, and the voltage-stabilizing diode and the second voltage-dividing resistor are connected in parallel.

[0011] Compared with the prior art, the beneficial effects achieved by the utility model are as follows: the utility model is designed with a lithium battery charging protection circuit. When the charging voltage exceeds 4.2V, the MOS is shut down to stop charging, thereby preventing the battery from being overcharged, thereby avoiding the risk of battery overcharging causing battery temperature rise and electrolyte decomposition leading to spontaneous combustion and rupture, and at the same time preventing the problem of battery degradation leading to reduced durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 This is a circuit diagram of the utility model.

[0014] In the figure: 1. Positive voltage pole; 2. First voltage-dividing resistor; 3. Gate pull-up resistor; 4. Zener diode; 5. Second voltage-dividing resistor; 6. Battery body; 7. MOS effect tube; 8. Ground terminal. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0016] See also Figure 1The utility model provides an embodiment: a lithium battery charging protection implementation circuit, including a battery body 6, one end of the battery body 6 is connected in series with a MOS effect tube 7, and the source of the MOS effect tube 7 is electrically connected to the negative electrode of the battery body 6, and the drain of the MOS effect tube 7 is electrically connected to the ground terminal 8; the positive electrode of the battery body 6 is electrically connected to a voltage positive electrode 1, and the voltage positive electrode 1 is used to connect a charging power source; the voltage positive electrode 1 is electrically connected to a first voltage dividing resistor 2; the first voltage dividing resistor 2 is electrically connected to a second voltage dividing resistor 5, and the first voltage dividing resistor 2 and the second voltage dividing resistor 5 are connected in series with each other, and the second voltage dividing resistor 5 is electrically connected to the ground terminal 8. The resistor 5 is electrically connected to the ground terminal 8, and the first voltage-dividing resistor 2 and the second voltage-dividing resistor 5 are used for voltage division to reduce the voltage at both ends of the circuit; the voltage positive electrode 1 is electrically connected to the gate pull-up resistor 3, and the gate pull-up resistor 3 is used to protect the MOS effect tube 7 to prevent the MOS effect tube 7 from malfunctioning or being broken down; the gate pull-up resistor 3 is electrically connected to the gate of the MOS effect tube 7, and the voltage-stabilizing diode 4 is used to obtain a stable voltage; the gate pull-up resistor 3 is electrically connected to the voltage-stabilizing diode 4, and the voltage-stabilizing diode 4 is electrically connected to the gate of the MOS effect tube 7, and the voltage-stabilizing diode 4 and the second voltage-dividing resistor 5 are connected in parallel with each other;

[0017] Working principle: When the utility model is used for lithium battery charging protection, the charging power supply is connected through the voltage positive electrode 1, and the voltage at both ends of the circuit is reduced by dividing the voltage through the first voltage dividing resistor 2 and the second voltage dividing resistor 5, and a higher stable voltage is obtained through the voltage stabilizing diode 4 to charge the battery body 6. When the control IC monitors that the voltage of the battery body 6 reaches the overcharge cut-off voltage and the duration meets the delay time of the overcharge voltage, the control IC will turn off the MOS effect tube 7 and cut off the charging circuit. At this time, the battery body 6 can only discharge to prevent the battery from overcharging. The condition for releasing the overcharge protection is that the voltage at both ends of the battery body 6 drops to the overcharge recovery voltage of the protection IC, or a load is added to the output end of the battery body 6 to discharge and discharge to a voltage less than the overcharge protection voltage. The gate pull-up resistor 3 is used to protect the MOS effect tube 7 to prevent the MOS effect tube 7 from malfunctioning or being broken down, and the ground terminal 8 is used for the grounding protection circuit.

[0018] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A lithium battery charging protection implementation circuit, comprising a battery body (6), characterized in that: One end of the battery body (6) is connected in series with a MOS effect tube (7), and the source electrode of the MOS effect tube (7) is electrically connected to the negative electrode of the battery body (6), and the drain electrode of the MOS effect tube (7) is electrically connected to the ground terminal (8).

2. A lithium battery charging protection implementation circuit according to claim 1, characterized in that: The positive electrode of the battery body (6) is electrically connected to the positive voltage electrode (1).

3. A lithium battery charging protection implementation circuit according to claim 2, characterized in that: The voltage positive electrode (1) is electrically connected to a first voltage dividing resistor (2).

4. A lithium battery charging protection implementation circuit according to claim 3, characterized in that: The first voltage-dividing resistor (2) is electrically connected to a second voltage-dividing resistor (5), and the first voltage-dividing resistor (2) and the second voltage-dividing resistor (5) are connected in series with each other, and the second voltage-dividing resistor (5) is electrically connected to a ground terminal (8).

5. A lithium battery charging protection implementation circuit according to claim 3, characterized in that: The voltage positive electrode (1) is electrically connected to a gate pull-up resistor (3).

6. A lithium battery charging protection implementation circuit according to claim 5, characterized in that: The gate pull-up resistor (3) is electrically connected to the gate of the MOS effect tube (7).

7. A lithium battery charging protection implementation circuit according to claim 5, characterized in that: The gate pull-up resistor (3) is electrically connected to a voltage-stabilizing diode (4), and the voltage-stabilizing diode (4) is electrically connected to the gate of the MOS effect tube (7), and the voltage-stabilizing diode (4) and the second voltage-dividing resistor (5) are connected in parallel.

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