CN220964372U

CN220964372U - Charging protection circuit

Info

Publication number: CN220964372U
Application number: CN202322554973.7U
Authority: CN
Inventors: 江宜建; 秦满桃; 邓传强; 李润朝; 廖兴群
Original assignee: Guangdong Highpower New Energy Technology Co Ltd
Current assignee: Guangdong Highpower New Energy Technology Co Ltd
Priority date: 2023-09-19
Filing date: 2023-09-19
Publication date: 2024-05-14
Anticipated expiration: 2033-09-19

Abstract

The utility model relates to the technical field of battery protection, in particular to a charging protection circuit; the device comprises a battery connecting end, a load connecting end, a fuse, a switching tube, an overvoltage protection chip, an AFE chip and a main control chip, wherein one end of the fuse is connected with the positive electrode of the battery connecting end, the other end of the fuse is connected with the positive electrode of the load connecting end, the input end of the overvoltage protection chip and the input end of the AFE chip are both used for being connected with a battery cell, the output end of the overvoltage protection chip is connected with the input end of the switching tube, the output end of the AFE chip is respectively connected with the input end of the switching tube and the input end of the main control chip, and the output end of the main control chip is connected with the input end of the switching tube; the scheme can carry out multiple protection through the combination of an overvoltage protection chip, an AFE chip and an AEF chip and a main control chip; and the trigger protection value in the AFE chip can be preset according to actual conditions, so that the method has higher practicability.

Description

Charging protection circuit

Technical Field

The utility model relates to the technical field of battery protection, in particular to a charging protection circuit.

Background

The current secondary protection of lithium battery mainly uses a special secondary protection IC to collect voltage information, and judges whether the voltage value collected by the secondary protection IC exceeds the protection value set in the IC or not so as to output a high-level signal, so that an external N-channel MOSFET is conducted and short circuit is generated between battery terminals, thereby cutting off an internal fuse and preventing the battery pack from recharging.

The protection mode is single, and when the primary protection failure triggers the secondary protection condition, once the secondary protection IC sampling circuit is abnormal or the control signal output is abnormal, the function of the whole secondary protection circuit of the lithium battery is failed, and the lithium battery can be exploded or ignited due to continuous overcharge. Secondly, the protection values of the secondary protection IC are fixed after being set and cannot be changed, and only one protection value can be set. Operability is not flexible enough.

Therefore, it is important for those skilled in the art to design a charge protection circuit with multiple protection and adjustable protection value.

Disclosure of utility model

The embodiment of the utility model aims to solve the technical problems of insufficient secondary protection safety and unadjustable protection value in the prior art by providing a charging protection circuit with multiple protection and adjustable protection value.

The utility model discloses a charging protection circuit which is characterized by comprising a battery connecting end, a load connecting end, a fuse, a switch tube, an overvoltage protection chip, an AFE chip and a main control chip, wherein one end of the fuse is connected with the positive electrode of the battery connecting end, the other end of the fuse is connected with the positive electrode of the load connecting end, the input end of the overvoltage protection chip and the input end of the AFE chip are both connected with a battery cell, the output end of the overvoltage protection chip is connected with the input end of the switch tube, the output end of the AFE chip is respectively connected with the input end of the switch tube and the input end of the main control chip, the output end of the main control chip is connected with the input end of the switch tube, and the output end of the switch tube is connected with the fuse.

Optionally, the switch tube is a first MOS tube, a gate of the first MOS tube is connected to the overvoltage protection chip and the output end of the AFE chip, a drain of the first MOS tube is connected to the fuse, and a source of the first MOS tube is grounded.

Optionally, a first protection diode is arranged between the gate of the first MOS transistor and the output end of the overvoltage protection chip.

Optionally, a second protection diode is arranged between the grid electrode of the first MOS tube and the output end of the AFE chip.

Optionally, a protection capacitor and a third protection diode are arranged between the output end of the main control chip and the grid electrode of the first MOS tube.

Optionally, the charging protection circuit further includes a plurality of sampling resistors, one end of each sampling resistor is connected with the battery cell, and the other end of each sampling resistor is connected with the input ends of the overvoltage protection chip and the AFE chip respectively.

Optionally, a plurality of sampling resistors are all connected in parallel with a filter capacitor.

Optionally, the main control chip is provided with a charging control pin and a discharging control pin, the charging control pin is provided with a charging control module, and the discharging control pin is provided with a discharging control module.

Optionally, the charging control module includes a first resistor and a second MOS tube, a gate of the second MOS tube is connected to the charging control pin, and the first resistor is disposed between the gate of the second MOS tube and the charging control pin.

Optionally, the discharge control module includes a second resistor and a third MOS tube, a gate of the third MOS tube is connected to the discharge control pin, and the second resistor is disposed between the gate of the third MOS tube and the discharge control pin.

Compared with the prior art, the charging protection circuit provided by the embodiment of the utility model has the beneficial effects that: the charging protection can be realized by acquiring the core voltage through the overvoltage protection chip, the charging protection can be realized by simulating the acquired core voltage through the AFE chip, and the charging protection can be realized by a mode of matching the AEF chip and the main control chip, so that the charging multiple protection is realized, the protection is more comprehensive, and the safety is realized; further, the trigger protection value in the AFE chip can be preset according to actual conditions, so that the AFE chip has more application scenes and has practicability.

Drawings

The technical scheme of the utility model will be further described in detail below with reference to the accompanying drawings and examples, wherein:

Fig. 1 is a schematic structural diagram of a charge protection circuit according to an embodiment of the present utility model;

Fig. 2 is a circuit diagram of a charge protection circuit according to an embodiment of the present utility model.

Detailed Description

It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be combined with each other. Preferred embodiments of the present utility model will now be described in detail with reference to the accompanying drawings.

As shown in fig. 1, the present utility model provides a preferred embodiment of a charge protection circuit.

Referring to fig. 1, the charging protection circuit comprises a battery connection end 1, a load connection end 2, a fuse 3, a switch tube 4, an overvoltage protection chip 5, an AFE chip 6 and a main control chip 7, wherein one end of the fuse 3 is connected with the positive electrode of the battery connection end 1, the other end of the fuse 3 is connected with the positive electrode of the load connection end 2, the input end of the overvoltage protection chip 5 and the input end of the AFE chip 6 are both used for being connected with a battery core of the battery, the output end of the overvoltage protection chip 5 is connected with the input end of the switch tube 4, the output end of the AFE chip 6 is respectively connected with the input end of the switch tube 4 and the input end of the main control chip 7, and the output end of the main control chip 7 is connected with the input end of the switch tube 4.

Specifically, referring to fig. 1, a battery connection terminal 1 is mainly used for connecting a battery, the battery connection terminal 1 includes a positive electrode b+, a negative electrode B-, and a plurality of battery cell connection terminals 11, a load connection terminal 2 is mainly used for connecting a load, and the load connection terminal 2 includes a positive electrode p+ and a negative electrode P-; the fuse 3 is mainly used for charging protection, and the fuse 3 is arranged between the positive electrode B+ of the battery connecting end 1 and the positive electrode P+ of the load connecting end 2; during charging, the fuse 3 will be blown when the battery output voltage is too high to cut off the line between the battery and the load.

Further, referring to fig. 1, the overvoltage protection chip 5 is mainly used for overvoltage protection, the input ends of the overvoltage protection chip 5 are respectively connected with the plurality of battery cell connection ends 11, and the overvoltage protection chip 5 collects the voltage information of each battery cell in the lithium battery pack through its own voltage sampling channel; the output end of the overvoltage protection chip 5 is connected with the switch tube 4, when the voltage value collected by the overvoltage protection chip 5 reaches the internal set value, the overvoltage protection chip 5 outputs a high level to the switch tube 4, the switch tube 4 is opened, the fuse 3 is heated and fused to disconnect a charging circuit, and then charging is stopped.

It should be noted that, the hardware of the overvoltage protection chip 5 has a fixed voltage protection value, specific data of the voltage protection value is determined according to the hardware of the chip, and if the voltage value collected by the overvoltage protection chip 5 reaches the voltage protection value of the hardware of the chip, a high level is output to the switching tube 4.

Further, referring to fig. 1, the AFE chip 6 is mainly used for analog acquisition, the input ends of the AFE chip 6 are respectively connected with the plurality of battery cell connection ends 11, the AFE chip 6 acquires voltage information of each battery cell in the lithium battery pack through a voltage acquisition channel of the AFE chip 6, and when the voltage value acquired by the AFE chip 6 reaches a preset trigger protection value, a high level is output; the specific trigger protection value of the AFE chip 6 is preset, and can be set correspondingly according to the needs.

Further, referring to fig. 1, the main control chip 7 is mainly used for data processing and sending a control instruction, and the high level output by the AFE chip 6 can be output to the switching tube 4, and the switching tube 4 is directly opened, so that the fuse 3 is heated and melted to disconnect a charging circuit, and further, charging is stopped; the fuse 3 is heated and fused by being capable of being output to the main control chip 7, and the main control chip 7 receives the high level and controls the switch to be turned on, so that a charging circuit is disconnected, and charging is stopped.

The current secondary protection of the lithium battery mainly comprises the steps of collecting voltage information through a single secondary protection IC, judging whether the voltage value collected by the secondary protection IC exceeds a protection value set in the IC or not through the voltage value collected by the secondary protection IC, so that an external N-channel MOSFET is conducted, short circuits are generated between battery terminals, and internal fuses are cut off, and the battery pack is prevented from being charged again; operability is not flexible enough.

In the embodiment, the charging protection can be realized by acquiring the voltage of the current core through the overvoltage protection chip, the charging protection can be realized by simulating the acquisition of the voltage of the current core through the AFE chip, the charging protection can be realized by the cooperation mode of the AEF chip and the main control chip, and the charging multiple protection is realized, so that the protection is more comprehensive and the safety is realized; further, the trigger protection value in the AFE chip can be preset according to actual conditions, so that the AFE chip has more application scenes and has practicability.

In one embodiment, referring to fig. 1 and 2, the switch tube 4 is a first MOS tube Q1, the gate of the first MOS tube Q1 is connected to the output ends of the overvoltage protection chip 5 and the AFE chip 6, the drain of the first MOS tube Q1 is connected to the fuse 3, and the source of the first MOS tube Q1 is grounded.

Specifically, referring to fig. 1 and 2, the gate of the first MOS transistor Q1 is connected to the output end of the overvoltage protection chip 5, the output end of the AFE chip 6, and the output end of the main control chip 7, respectively, so as to receive the level information output by the overvoltage protection chip 5, the AFE chip 6, and the main control chip 7, and turn on or off according to the level information; when the output end of the overvoltage protection chip 5 outputs a high level, or the output end of the AFE chip 6 outputs a high level, or the output end of the main control chip 7 outputs a high level, the first MOS tube Q1 is started, the fuse 3 is heated and fused, and then a charging circuit is cut off, so that charging is finished.

In one embodiment, referring to fig. 1 and 2, a first protection diode D1 is disposed between the gate of the first MOS transistor Q1 and the output terminal of the overvoltage protection chip 5.

Specifically, referring to fig. 1 and 2, the anode of the first protection diode D1 is connected to the output terminal of the overvoltage protection chip 5, and the cathode of the first protection diode D1 is connected to the gate of the first MOS transistor Q1 for protecting the overvoltage protection chip 5.

In one embodiment, referring to fig. 1 and 2, a second protection diode D2 is disposed between the gate of the first MOS transistor Q1 and the output terminal of the AFE chip 6.

Specifically, referring to fig. 1 and 2, the anode of the second protection diode D2 is connected to the output terminal of the AFE chip 6, and the cathode of the second protection diode D2 is connected to the gate of the first MOS transistor Q1 for protecting the AFE chip 6.

In one embodiment, referring to fig. 1 and 2, a protection capacitor C7 and a third protection diode D3 are disposed between the output end of the main control chip 7 and the gate of the first MOS transistor Q1.

Specifically, referring to fig. 1 and 2, one end of a protection capacitor C7 is connected to an output end of the main control chip 7, a resistor R9 is further disposed between the protection capacitor C7 and the output end of the main control chip 7, the other end of the protection capacitor C7 is connected to an anode of a third protection diode D3, and a cathode of the third protection diode D3 is connected to a gate of the first MOS transistor Q1; the protection capacitor C7 is turned on at an instant of charging and turned off after being fully charged, so as to protect the main control chip 7.

In one embodiment, referring to fig. 1 and 2, the charging protection circuit further includes a plurality of sampling resistors, one ends of the sampling resistors are connected to the battery cells, and the other ends of the sampling resistors are connected to the input ends of the overvoltage protection chip 5 and the AFE chip 6, respectively.

Specifically, referring to fig. 1 and 2, one end of a sampling resistor is connected with a battery cell and is mainly used for collecting sampling current of battery telecommunication, the other end of the sampling resistor is respectively connected with an input end of an overvoltage protection chip 5 and an input end of an AFE chip 6, the overvoltage protection chip 5 can obtain the sampling current through the sampling resistor and calculate sampling voltage, and then the sampling voltage is compared with an overvoltage trigger value fixed by the sampling resistor, when the sampling voltage is too high, a high level is output to a first MOS tube Q1, and otherwise, a low level is output; the AFE protection chip can obtain sampling current through the sampling resistor and calculate sampling voltage, and then through comparing the sampling voltage with a trigger value preset by the AFE protection chip, when the sampling voltage is too high, the AFE protection chip outputs a high level to the first MOS tube Q1, and otherwise, outputs a low level.

Referring to the drawings, referring to fig. 1 and 2, taking a 4-cell as an example, the battery includes four cells B1, B2, B3, and B4, respectively, and the charge protection circuit includes four sampling resistors, respectively R4 connected to B1 to sample a B1 current, R3 connected to B2 to sample a B2 current, R2 connected to B4 to sample a B4 current, and R1 connected to B4 to sample a B4 current; the other ends of the four sampling resistors are respectively connected to the input ends of the overvoltage protection chip 5 and the AFE chip 6 so as to obtain the output voltages of the four battery cells.

In one embodiment, a filter capacitor is disposed on each of the plurality of sampling resistors.

Specifically, referring to fig. 2, a filter capacitor C1 is disposed on a sampling resistor R1, a filter capacitor C3 is disposed on a sampling resistor R2, a filter capacitor C3 is disposed on a sampling resistor R3, and a filter capacitor C4 is disposed on a sampling resistor R4.

In one embodiment, referring to fig. 2, the charge protection circuit further includes a charge control module 8 and a discharge control module 9, the main control chip 7 is provided with a charge control pin CO and a discharge control pin DO, the charge control pin CO is provided with the charge control module 8, and the discharge control pin DO is provided with the discharge control module 9.

Specifically, referring to fig. 2, the charge control module 8 and the discharge control module 9 are mainly used for managing the charge and discharge process of the battery so as to ensure safe and efficient charge and discharge of the battery; wherein the charging control module 8 is responsible for monitoring and controlling the charging process of the battery; the discharge control module 9 is responsible for monitoring and controlling the discharge process of the battery.

In one embodiment, referring to fig. 2, the charge control module 8 includes a first resistor R11 and a second MOS transistor Q3, a gate of the second MOS transistor Q3 is connected to the charge control pin CO, and the first resistor R11 is disposed between the gate of the second MOS transistor Q3 and the charge control pin CO.

Specifically, referring to fig. 2, one end of the first resistor R11 is connected to the charge control pin CO, and the other end of the first resistor R11 is connected to the gate of the second MOS transistor Q3.

In one embodiment, referring to fig. 2, the discharge control module 9 includes a second resistor R10 and a third MOS transistor Q2, a gate of the third MOS transistor Q2 is connected to the discharge control pin DO, and the second resistor R10 is disposed between the gate of the third MOS transistor Q2 and the discharge control pin DO.

Specifically, referring to fig. 2, one end of the second resistor R10 is connected to the discharge control pin DO, and the other end of the second resistor R10 is connected to the gate of the third MOS transistor Q2.

It should be understood that the foregoing embodiments are merely illustrative of the technical solutions of the present utility model, and not limiting thereof, and that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art; all such modifications and substitutions are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

1. The utility model provides a charge protection circuit, its characterized in that includes battery link, load link, fuse, switch tube, overvoltage protection chip, AFE chip and main control chip, the one end of fuse with the positive pole of battery link is connected, the other end of fuse with the positive pole of load link is connected, the input of overvoltage protection chip with the input of AFE chip all is used for being connected with the battery cell, the output of overvoltage protection chip with the input of switch tube is connected, the output of AFE chip connect respectively in the input of switch tube with the input of main control chip, the output of main control chip with the input of switch tube is connected, the output of switch tube with the fuse is connected.

2. The charge protection circuit of claim 1, wherein the switching tube is a first MOS tube, a gate of the first MOS tube is connected to the output terminals of the overvoltage protection chip and the AFE chip, a drain of the first MOS tube is connected to the fuse, and a source of the first MOS tube is grounded.

3. The charge protection circuit of claim 2, wherein a first protection diode is disposed between the gate of the first MOS transistor and the output of the overvoltage protection chip.

4. The charge protection circuit of claim 2, wherein a second protection diode is disposed between the gate of the first MOS transistor and the output of the AFE chip.

5. The charge protection circuit of claim 2, wherein a protection capacitor and a third protection diode are disposed between the output terminal of the main control chip and the gate of the first MOS transistor.

6. The charge protection circuit of claim 1, further comprising a plurality of sampling resistors, one end of each sampling resistor being connected to a battery cell, and the other end of each sampling resistor being connected to the input terminals of the overvoltage protection chip and the AFE chip, respectively.

7. The charge protection circuit of claim 6, wherein a filter capacitor is connected in parallel to each of the plurality of sampling resistors.

8. The charge protection circuit of claim 1, wherein the main control chip is provided with a charge control pin and a discharge control pin, the charge control pin is provided with a charge control module, and the discharge control pin is provided with a discharge control module.

9. The charge protection circuit of claim 8, wherein the charge control module comprises a first resistor and a second MOS transistor, a gate of the second MOS transistor is connected to the charge control pin, and the first resistor is disposed between the gate of the second MOS transistor and the charge control pin.

10. The charge protection circuit of claim 8, wherein the discharge control module comprises a second resistor and a third MOS transistor, a gate of the third MOS transistor is connected to the discharge control pin, and the second resistor is disposed between the gate of the third MOS transistor and the discharge control pin.