CN219960153U

CN219960153U - Battery cell protection circuit and battery cell management system

Info

Publication number: CN219960153U
Application number: CN202320878958.5U
Authority: CN
Inventors: 陈龙扣; 桂登宇; 陈明道
Original assignee: Shenzhen Baseus Technology Co Ltd
Current assignee: Shenzhen Baseus Technology Co Ltd
Priority date: 2023-04-17
Filing date: 2023-04-17
Publication date: 2023-11-03
Anticipated expiration: 2033-04-17

Abstract

The embodiment of the utility model provides a battery core protection circuit and a battery core management system, wherein the battery core protection circuit comprises: the device comprises a switch driving module, a protection switch and a battery cell group; the battery cell group consists of at least one battery cell unit; one end of the switch driving module is connected with the first end of the protection switch; the other end of the switch driving module is a level signal control end; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group; when the physical state information of any one of the battery cells in the battery cell group is monitored to be in an abnormal working state, the switch driving module is controlled to be turned off according to a first control signal received by the level signal control module, and the voltage flowing in the branch of the protection switch is blocked so as to drive the protection switch to be turned off; when the protection switch is turned off, a charging or discharging loop formed by the first negative electrode terminal and the first positive electrode terminal of the battery cell group is disconnected, and the battery cell group is controlled to be in an uncharged or uncharged state.

Description

Battery cell protection circuit and battery cell management system

Technical Field

The utility model relates to the technical field of battery management, in particular to a battery cell protection circuit and a battery cell management system.

Background

A battery management system (Battery Management System, BMS), also called a battery manager, is primarily used to manage and maintain the individual cells in the battery cell stack. At present, a plurality of battery core units are widely applied to the fields of energy storage power supplies, floor sweeping machines, electric tools, electric bicycles, unmanned aerial vehicles and the like, various abnormal conditions possibly occur in the use process of a battery pack formed by the plurality of battery core units, the states of the battery core units in the battery pack are monitored through a BMS, the states of overcharging or overdischarging of a battery can be prevented, and the service life of the battery is prolonged.

At present, based on the in-process that BMS monitored the battery, utilize two MOS pipes of two-way charge-discharge, monitor the state of each electric core unit in the battery through this structure, realize protecting BMS circuit, its circuit structure is complicated, and the great current path of two MOS pipes of flow through will lead to great switching on pressure drop, and then can make charging tube and discharge tube produce higher power loss.

Disclosure of Invention

In view of the foregoing, it is desirable to provide a cell protection circuit and a cell management system that can simplify the circuit structure and reduce the power loss in the circuit structure.

In order to achieve the above purpose, the technical scheme of the utility model is realized as follows:

in a first aspect, an embodiment of the present utility model provides a battery cell protection circuit, including: the device comprises a switch driving module, a protection switch and a battery cell group; the battery cell group consists of at least one battery cell unit;

one end of the switch driving module is connected with the first end of the protection switch; the other end of the switch driving module is a level signal control end; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group;

under the condition that the physical state information of any one of the battery cells in the battery cell group is in an abnormal working state, the switch driving module is controlled to be turned off according to a first control signal received by the level signal control module, and the voltage flowing in a branch of the protection switch is blocked so as to drive the protection switch to be turned off; when the protection switch is turned off, a charging or discharging loop formed by the first negative electrode terminal and the first positive electrode terminal of the battery cell group is disconnected, and the battery cell group is controlled to be in an uncharged or uncharged state.

In the above-mentioned cell protection circuit, the switch driving module includes a first transistor and a second transistor;

The source electrode of the first transistor is grounded; the drain electrode of the first transistor is connected with the grid electrode of the second transistor; the grid electrode of the first transistor is a level signal control end; the source electrode of the second transistor is connected with the positive electrode of the direct current power supply; the drain electrode of the second transistor is connected with the first end of the protection switch; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group;

under the condition that the physical state information of any one of the battery core units in the battery core group is in an abnormal working state, the first transistor is controlled to be turned off according to a first control signal received by the grid electrode of the first transistor, the second transistor is turned off when the first transistor is turned off, and the voltage flowing in a branch of the protection switch is blocked so as to drive the protection switch to be turned off.

In the above-mentioned cell protection circuit, the protection switch includes a gallium nitride transistor;

the source electrode of the first transistor is grounded; the drain electrode of the first transistor is connected with the grid electrode of the second transistor; the grid electrode of the first transistor is a level signal control end; the source electrode of the second transistor is connected with the positive electrode of the direct current power supply; the drain electrode of the second transistor is connected with the grid electrode of the gallium nitride transistor; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; the second drain electrode of the gallium nitride transistor is connected with the second negative terminal of the battery cell group;

Under the condition that the physical state information of any one of the battery core units in the battery core group is in an abnormal working state, the first transistor is controlled to be turned off according to a first control signal received by the grid electrode of the first transistor, the second transistor is turned off when the first transistor is turned off, and the voltage flowing into the grid electrode of the gallium nitride transistor is blocked, so that the gallium nitride transistor is driven to be in a turned-off state.

In the above-mentioned battery cell protection circuit, the battery cell protection circuit further includes: a protection switch protection module; the switch driving module comprises a first transistor and a second transistor;

the first end of the protection switch protection module is connected with the first end of the protection switch; the second end of the protection switch protection module is grounded; the third end of the protection switch protection module is connected with a branch where the drain electrode of the first transistor and the grid electrode of the second transistor are positioned; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group;

when the protection switch is driven to be turned on or off by the switch driving module, the protection switch protection module outputs current on a branch where the drain electrodes of the protection switch and the second transistor are positioned to the grounding end.

In the above-mentioned cell protection circuit, the protection switch protection module includes a third transistor, a first diode, and a first resistor;

the source electrode of the third transistor is grounded; the drain electrode of the third transistor is connected with the cathode electrode of the first diode; the grid electrode of the third transistor is connected with the branch circuit where the drain electrode of the first transistor and the grid electrode of the second transistor are positioned; the anode of the first diode is connected with one end of the first resistor; the other end of the first resistor is connected with the first end of the protection switch; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group;

when the protection switch is driven to be turned on or off by the switch driving module, current on a second branch where the drains of the protection switch and the second transistor are located is output to the ground end through a first branch consisting of a first resistor, a first diode and a third transistor.

In the above-mentioned battery cell protection circuit, the battery cell protection circuit further includes: the battery cell is reversely connected with the protection module; the protection switch is a gallium nitride transistor;

the first end of the battery cell reverse connection protection module is connected with the second negative terminal of the battery cell group; the second end of the cell reverse connection protection module is connected with the grid electrode of the gallium nitride transistor; the third end of the battery cell reverse connection protection module is connected with the second positive terminal of the battery cell group; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; the second drain electrode of the gallium nitride transistor is connected with the second negative terminal of the battery cell group;

Under the condition that the second negative electrode terminal of the battery cell group is reversely connected with the second positive electrode terminal of the battery cell group, the voltage flowing into the battery cell reverse connection protection module is reversed, so that the battery cell reverse connection protection module is conducted, the protection switch is conducted with a branch formed by the battery cell reverse connection protection module, and the voltage flowing through the protection switch is adjusted to control the protection switch to be turned off.

In the above-mentioned battery cell protection circuit, the battery cell reverse connection protection module includes a fourth transistor and a second resistor; the protection switch comprises a gallium nitride transistor;

the grid electrode of the fourth transistor is connected with one end of the second resistor; the other end of the second resistor is connected with a second negative terminal of the battery cell group; the drain electrode of the fourth transistor is connected with the grid electrode of the gallium nitride transistor; the source electrode of the fourth transistor is connected with the second positive terminal of the battery cell group; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; the second drain electrode of the gallium nitride transistor is connected with the second negative terminal of the battery cell group;

under the condition that the second negative electrode terminal of the battery cell group is reversely connected with the second positive electrode terminal of the battery cell group, the voltage flowing in by the grid electrode of the fourth transistor is reversed, so that the fourth transistor is turned on, a third branch consisting of the protection switch, the fourth transistor and the second resistor is turned on, and the voltage flowing through the grid electrode of the gallium nitride transistor is adjusted to control the protection switch to be turned off.

In the above-mentioned battery cell protection circuit, the battery cell protection circuit further includes: an overvoltage clamping protection module; the overvoltage clamping protection module comprises a fourth branch and a fifth branch; the fourth branch consists of a second diode, a third diode and a first voltage stabilizing diode; the fifth branch consists of a fourth diode, a fifth diode and a second zener diode; the switch driving module comprises a first transistor and a second transistor; the protection switch is a gallium nitride transistor;

the cathode of the first zener diode and the cathode of the second zener diode are respectively connected with the drain of the second transistor and the branch where the grid of the gallium nitride transistor is positioned; the anode of the first voltage stabilizing diode is connected with the anode of the second diode, the cathode of the second diode is connected with the anode of the third diode, and the cathode of the third diode is connected with the first drain electrode of the gallium nitride transistor; the anode of the second voltage stabilizing diode is connected with the anode of the fourth diode, the cathode of the fourth diode is connected with the anode of the fifth diode, and the cathode of the fifth diode is connected with the second drain electrode of the gallium nitride transistor;

when the switch driving module drives the protection switch to be turned on or off, the fourth branch and/or the fifth branch control the on or off driving voltage of the gallium nitride transistor to be within a preset voltage threshold.

In the above-mentioned battery cell protective circuit, under the condition that the physical state information of each battery cell unit in the battery cell group is in the normal working condition of monitoring, according to the second control signal that the signal control end of the level receives, control the switch to drive the module to turn on, through the voltage flowing in on the branch of the protective switch, in order to drive the protective switch to turn on; when the protection switch is conducted, a charging or discharging loop formed by the first negative electrode terminal and the first positive electrode terminal of the battery cell group is conducted, and the battery cell group is controlled to be in a charging or discharging state.

In a second aspect, an embodiment of the present utility model provides a battery management system, which includes a battery protection circuit.

The embodiment of the utility model provides a battery core protection circuit and a battery core management system, wherein the battery core protection circuit comprises: the device comprises a switch driving module, a protection switch and a battery cell group; the battery cell group consists of at least one battery cell unit; one end of the switch driving module is connected with the first end of the protection switch; the other end of the switch driving module is a level signal control end; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group; when the physical state information of any one of the battery cells in the battery cell group is monitored to be in an abnormal working state, the switch driving module is controlled to be turned off according to a first control signal received by the level signal control module, and the voltage flowing in the branch of the protection switch is blocked so as to drive the protection switch to be turned off; when the protection switch is turned off, a charging or discharging loop formed by the first negative electrode terminal and the first positive electrode terminal of the battery cell group is disconnected, and the battery cell group is controlled to be in an uncharged or uncharged state. By adopting the implementation scheme, in the process of protecting the battery cells, the working state of the battery cell group is monitored, the level signal output by the level signal control end is controlled, the on and off of the switch driving module is further controlled by the output level signal, and the switch driving module is connected with the protection switch, so that the protection switch is driven to be opened and closed, and the battery cells are further controlled to be in a charging or discharging state and an uncharged or uncharged state. By utilizing the circuit structure, the switch driving module can be controlled to drive the protection switch to be turned on and off only by one path of level signal, and the circuit structure is simple; when the battery core is in an uncharged or uncharged state, the protection switch is in an off state, no current or voltage flows, and the power loss in the circuit structure can be reduced.

Drawings

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

fig. 2 is a schematic diagram of a second embodiment of a cell protection circuit according to the present utility model;

fig. 3 is a schematic diagram III of a structure of a protection circuit for a battery cell according to an embodiment of the present utility model;

fig. 4 is a schematic diagram of a structure of a battery cell protection circuit according to an embodiment of the present utility model;

fig. 5 is a schematic diagram of a battery core protection circuit according to an embodiment of the present utility model;

fig. 6 is a schematic diagram of a battery core protection circuit according to an embodiment of the present utility model;

fig. 7 is a schematic diagram seventh of a structure of a protection circuit for a battery cell according to an embodiment of the present utility model;

fig. 8 is a schematic diagram eight of a structure of a protection circuit for a battery cell according to an embodiment of the present utility model;

fig. 9 is a schematic diagram nine of a structure of a protection circuit for a battery cell according to an embodiment of the present utility model;

fig. 10 is a schematic structural diagram of a BMS system according to an embodiment of the present utility model;

FIG. 11 is a schematic diagram of a prior art cell protection circuit structure;

fig. 12 is a flow chart of the working principle of the BMS system according to the embodiment of the present utility model.

Detailed Description

In order to more fully understand the features and technical content of the embodiments of the present utility model, the following detailed description of the embodiments of the present utility model refers to the accompanying drawings, which are not intended to limit the embodiments of the present utility model.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein is for the purpose of describing embodiments of the utility model only and is not intended to be limiting of the utility model.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with one another without conflict. It should also be noted that the term "first/second/third" is used merely to distinguish similar objects and does not represent a specific ordering of objects, it being understood that the "first/second/third" may be interchanged with a specific order or sequence, as permitted, to enable embodiments of the utility model described herein to be implemented in an order other than that illustrated or described herein.

Currently, when a battery cell group is managed by a BMS, the BMS includes a motor control unit (Motor Control Unit, MCU), an Analog Front End (AFE), a battery cell protection module, and a battery cell balancing module. The MCU mainly realizes the functions of communication, data storage, command execution and the like among all the components; the AFE mainly realizes functions such as monitoring the voltage, the current and the temperature of the battery cells; the battery cell protection module mainly realizes functions such as overvoltage protection, overcurrent protection, overtemperature protection, short-circuit protection and the like of the battery cell, and the battery cell equalization module mainly realizes the function of equalization of the battery cell.

In some existing alternative embodiments, when an abnormality occurs in the BMS system, such as overcurrent, overvoltage, or short circuit, two N-type MOS transistors are commonly connected back to back in a circuit structure, and a drain side is used to block a charging input voltage or a discharging output voltage. In the conventional circuit structure of two bidirectional charge and discharge tubes, when charging and discharging are performed, current flows through the charge tube or the discharge tube, and a larger current path causes a larger conduction voltage drop, so that the charge and discharge tube has higher power loss.

In order to solve the technical problems in the prior art, an embodiment of the present utility model provides a battery cell protection circuit 1, as shown in fig. 1, the battery cell protection circuit 1 includes: the device comprises a switch driving module 10, a protection switch 11 and a battery cell group 12; wherein the battery cell group 12 is composed of at least one battery cell. Specifically, one end of the switch driving module 10 is connected to a first end of the protection switch 11; the other end of the switch driving module 10 is a level signal control end; the second end of the protection switch 11 is connected with a first negative terminal of the battery cell group 12; a third end of the protection switch 12 is connected to a second negative terminal of the battery cell stack 12.

In the embodiment of the utility model, the first control signal is a low level control signal. The cell stack may include a first negative terminal, a second negative terminal, a first positive terminal, and a second positive terminal.

Conversely, if the physical state information of each cell unit in the cell group is in the normal working state, the switch driving module is controlled to be conducted according to the second control signal received by the level signal control end, and the voltage flowing in the branch of the protection switch is used for driving the protection switch to be conducted; when the protection switch is conducted, a charging or discharging loop formed by the first negative electrode terminal and the first positive electrode terminal of the battery cell group is conducted, and the battery cell group is controlled to be in a charging or discharging state.

In the embodiment of the present utility model, the second control signal is a high level control signal.

In the embodiment of the utility model, through improving the battery cell protection module in the BMS, the purpose is to simplify a circuit and reduce the power loss of the power tube caused by a bidirectional charge and discharge tube structure adopted in the prior art.

Based on this, in the embodiment of the present utility model, by connecting the switch driving module 10 with the protection switch 11, the protection switch 11 is driven to be turned on and off by the switch driving module 10. I.e. it can be understood that the switch driving module 10 is a switch that opens or closes the protection switch 11.

In the embodiment of the present utility model, when the protection switch 11 works normally, that is, when the protection switch is in an on state, the battery cell group can perform normal charging and discharging, and conversely, when the protection switch is in an off state, the battery cell group does not perform charging or discharging.

In the embodiment of the present utility model, when the switch driving module 10 drives the protection switch 11 to be turned on or off, the switch driving module 10 may control the switch to be turned on or off through one path of level signal, specifically, when the level signal received by the switch driving module 10 is a low level control signal, the switch driving module 10 is turned off, and the switch driving module 10 is connected with the protection switch 11, so as to drive the protection switch 11 to be turned off; when the level signal received by the switch driving module 10 is the high level control signal, the switch driving module 10 is turned on, and the switch driving module 10 is connected to the protection switch 11, so that the protection switch 11 is driven to be turned on.

In the embodiment of the utility model, the high-level control signal and the low-level control signal are mainly determined by the physical state information of the monitored battery cell unit, when the physical state information of the battery cell unit is in a normal working state, the battery cell group is characterized as being capable of being normally charged or discharged, and at the moment, the high-level control signal is received by the level signal control end of the switch driving module 10 to drive the protection switch to be in a conducting state; when the physical state information of the battery cell unit is in an abnormal working state, the battery cell group is characterized in that normal charging or discharging cannot be performed, and in this case, the protection switch 11 needs to be driven to be turned off, so that the input current in the battery cell charging process or the output current in the battery cell discharging process is turned off.

In the embodiment of the utility model, the cell state of the cell unit can be physical state information such as voltage, current, temperature and the like. It can be understood that when the state of the battery cell is in an abnormal working state, that is, the battery cell is in an abnormal condition such as overcharge, overdischarge or over-temperature, in this case, if the battery cell continues to charge or discharge, the battery cell or the circuit will burn out.

Based on the above embodiment, it may be understood that if it is monitored that the physical state information of any one of the battery cells in the battery cell group is abnormal, the level signal control end of the switch driving module may receive the low level control signal, and may control the switch driving module to be turned off according to the low level control signal received by the level signal control end, in this case, no voltage flows into the branch of the protection switch, and the protection switch is turned off. After the protection switch is turned off, the branch where the protection switch is located is equivalent to an open circuit, so that the output of the voltage of the battery cell group or the input of the voltage to the battery cell group is forbidden, and the protection of the battery cell is realized.

In the embodiment of the present utility model, if it is monitored that the physical state information of all the battery cells included in the battery cell group is in the normal working state, the level signal control end of the switch driving module 10 may receive the high level control signal, and may control the switch driving module to be turned on according to the high level control signal received by the level signal control end, in this case, the protection switch is driven to be turned on by the voltage flowing in the branch of the protection switch, so it can be understood that the branch where the protection switch is located is turned on, and normal charging or discharging of the battery cell group may be realized.

It can be understood that in the process of protecting the battery cell, the battery cell protection circuit provided by the embodiment of the utility model controls the level signal output by the level signal control end by monitoring the working state of the battery cell group, and further controls the on and off of the switch driving module by the output level signal, so that the switch driving module is connected with the protection switch, and the protection switch is driven to be opened and closed, and then the battery cell is controlled to be in a charging or discharging state, an uncharged or uncharged state. By utilizing the circuit structure, the switch driving module can be controlled to drive the protection switch to be turned on and off only by one path of level signal, and the circuit structure is simple; when the battery core is in an uncharged or uncharged state, the protection switch is in an off state, no current or voltage flows, and the power loss in the circuit structure can be reduced.

Optionally, the switch driving module includes a first transistor and a second transistor; the source electrode of the first transistor is grounded; the drain electrode of the first transistor is connected with the grid electrode of the second transistor; the grid electrode of the first transistor is a level signal control end; the source electrode of the second transistor is connected with the positive electrode of the direct current power supply; the drain electrode of the second transistor is connected with the first end of the protection switch; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group.

Wherein the first control signal is a low level control signal.

In the embodiment of the present utility model, as shown in fig. 2, the switch driving module 10 may be composed of a first transistor Q1 and a second transistor Q2, and the types of Q1 and Q2 may be selected according to actual situations, which is not specifically limited in this scheme.

In the embodiment of the utility model, a source electrode of Q1 is connected with a ground end GND, a drain electrode of Q1 is connected with a grid electrode of Q2, the grid electrode of Q1 is a level signal control end GnD _EN, a source electrode of Q2 is connected with a positive electrode DC+ of a direct current power supply, a drain electrode of Q2 is connected with a first end of a protection switch, and a second end of the protection switch is connected with a first negative electrode terminal PACK-of a battery cell group; the third end of the protection switch is connected with a second negative terminal BAT-of the battery cell group.

In the embodiment of the utility model, if it is detected that the physical state information of the battery core is abnormal, that is, in an abnormal working state, the grid electrode of the Q1, that is, the first level signal received by the level signal control terminal GnD _en is a low level control signal, the Q1 is controlled to be turned off by the low level control signal, and then the Q2 connected with the drain electrode of the Q1 is controlled to be turned off, and the branches where the Q1 and the Q2 are located can drive the protection switch to be turned on and off, so that when the Q1 and the Q2 are turned off, that is, the switch driving module is turned off, the voltage flowing in the branches of the protection switch is blocked, and the protection switch is driven to be turned off. The charging or discharging loop corresponding to the battery cell group is disconnected, and the battery cell group is forbidden to be charged or is forbidden to be discharged, so that the protection of the battery cell group is realized.

And when each cell unit in the cell group is in a normal working state, the embodiment for realizing normal charging or discharging of the cell group is opposite to the above implementation manner, and is not described herein in detail.

Optionally, the protection switch comprises a gallium nitride transistor; the source electrode of the first transistor is grounded; the drain electrode of the first transistor is connected with the grid electrode of the second transistor; the grid electrode of the first transistor is a level signal control end; the source electrode of the second transistor is connected with the positive electrode of the direct current power supply; the drain electrode of the second transistor is connected with the grid electrode of the gallium nitride transistor; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; the second drain of the gallium nitride transistor is connected with the second negative terminal of the battery cell group.

Wherein the first control signal is a low level control signal.

In the embodiment of the present utility model, as shown in fig. 3, the protection switch is a gallium nitride transistor K1, the source electrode of Q1 is connected to the ground terminal GND, the drain electrode of Q1 is connected to the gate electrode of Q2, the gate electrode of Q1 is a level signal control terminal GnD _en, the source electrode of Q2 is connected to dc+, the drain electrode of Q2 is connected to the gate electrode of K1, the first drain electrode of K1 is connected to the first negative terminal PACK of the battery cell group, and the second drain electrode of K1 is connected to the second negative terminal BAT of the battery cell group.

In the embodiment of the present utility model, the implementation manner of turning on and off the driving gan transistor K1 may refer to the implementation manner of turning on and off the driving protection switch in the above embodiment, which is not described herein again.

Optionally, the battery cell protection circuit further comprises a protection switch protection module; the switch driving module comprises a first transistor and a second transistor; the first end of the protection switch protection module is connected with the first end of the protection switch; the second end of the protection switch protection module is grounded; the third end of the protection switch protection module is connected with a branch where the drain electrode of the first transistor and the grid electrode of the second transistor are positioned; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group;

In the embodiment of the utility model, in the process of protecting the battery core by using the battery core protection circuit, parasitic capacitance or induction electric quantity exists in the circuit structure, and if the parasitic capacitance or induction electric quantity is not released in time, the circuit is easy to damage.

In the embodiment of the utility model, as shown in fig. 4, a first end of the protection switch is connected with the protection switch protection module, and a second end of the protection switch protection module is grounded, so that when parasitic capacitance or induction electric quantity is generated in the circuit, the parasitic capacitance or induction electric quantity in the circuit can be output to the grounding end through the protection switch protection module.

Specifically, in the embodiment of the utility model, under the condition that the switch driving module drives the protection switch to be turned on or turned off, the protection switch protection module forms a rapid discharging loop, and the protection switch protection module outputs the current on the branch where the drain electrodes of the protection switch and the second transistor are positioned to the grounding end, so that the protection switch is prevented from being damaged in the processes of turning on and off.

Optionally, the protection switch protection module includes a third transistor, a first diode, and a first resistor; the source electrode of the third transistor is grounded; the drain electrode of the third transistor is connected with the cathode electrode of the first diode; the grid electrode of the third transistor is connected with the branch circuit where the drain electrode of the first transistor and the grid electrode of the second transistor are positioned; the anode of the first diode is connected with one end of the first resistor; the other end of the first resistor is connected with the first end of the protection switch; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group.

In the embodiment of the utility model, as shown in fig. 5, the protection switch protection module is composed of a third transistor Q3, a first diode D1 and a first resistor R1, the source electrode of Q3 is connected with a ground terminal GND, the drain electrode of Q3 is connected with the cathode of D1, the gate electrode of Q3 is connected with the branch where the drain electrode of Q1 and the gate electrode of Q2 are located, the anode of D1 is connected with one end of R1, the other end of R1 is connected with the first end of the protection switch, and the second end of the protection switch is connected with a first negative terminal PACK-of the battery cell group; the third end of the protection switch is connected with the second negative terminal BAT-of the battery cell group.

The protection switch can be a gallium nitride transistor K1, the circuit connection relation of the protection switch can be that a source electrode of the Q3 is connected with a grounding end GND, a drain electrode of the Q3 is connected with a cathode of the Q1, a grid electrode of the Q3 is respectively connected with a drain electrode of the Q1 and a branch circuit where a grid electrode of the Q2 is located, an anode of the D1 is connected with one end of the R1, the other end of the R1 is connected with a grid electrode of the K1, a first drain electrode of the K1 is connected with a first negative electrode terminal PACK-of the battery cell group, a second drain electrode of the K1 is connected with a second negative electrode terminal BAT-of the battery cell group, a source electrode of the Q1 is grounded, a grid electrode of the Q1 is a signal control port GnD _EN, a source electrode of the Q2 is connected with a positive electrode DC+ of a direct current power supply, and a drain electrode of the Q2 is connected with a grid electrode of the K1.

In the embodiment of the utility model, the first branch is formed by R1, D1 and Q3, namely the protection switch protection module, when the switch driving module drives the protection switch to be turned on or off, the first branch can output the current on the second branch where the drains of the protection switch K1 and the second transistor are positioned to the grounding end GND, so that the protection switch is prevented from being damaged in the processes of turning on and off.

Optionally, the cell protection circuit further includes: the battery cell is reversely connected with the protection module; the protection switch is a gallium nitride transistor; the first end of the battery cell reverse connection protection module is connected with the second negative terminal of the battery cell group; the second end of the cell reverse connection protection module is connected with the grid electrode of the gallium nitride transistor; the third end of the battery cell reverse connection protection module is connected with the second positive terminal of the battery cell group; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; the second drain of the gallium nitride transistor is connected with the second negative terminal of the battery cell group.

In the embodiment of the utility model, as shown in fig. 6, in order to prevent the second negative terminal and the second positive terminal of the battery cell group from being reversely connected in the battery cell protection circuit, a battery cell reverse connection protection module is designed in the battery cell protection circuit.

In the embodiment of the utility model, the protection switch is a gallium nitride transistor K1, the first end of the cell reverse connection protection module is connected with the second negative terminal BAT-of the cell group, and the second end of the cell reverse connection protection module is connected with the grid electrode of the K1; the third end of the battery cell reverse connection protection module is connected with a second positive terminal BAT+ of the battery cell group; the first drain electrode of K1 is connected with the first negative electrode terminal PACK-of the battery cell group, and the second drain electrode of K1 is connected with the second negative electrode terminal BAT-of the battery cell group.

In the embodiment of the utility model, under the condition of reverse connection of BAT-and BAT+, the protection of the circuit is realized by turning off the protection switch K1.

Specifically, under the condition that the second negative terminal BAT-of the battery cell group is reversely connected with the second positive terminal BAT+ of the battery cell group, namely, the first end of the battery cell reverse connection protection module is changed from the original input BAT-to BAT+, when the first end of the battery cell reverse connection protection module inputs BAT+, the battery cell reverse connection protection module is conducted, and then the branch where the protection switch and the battery cell reverse connection protection module are located is conducted, so that the potential of the grid electrode of the protection switch K1 is directly pulled down to BAT+, and the protection switch is controlled to be turned off, thereby realizing the protection of a circuit.

It should be noted that, even if the switch driving module drives the switch K1 to be turned on, it can be understood that the protection of the circuit is formed by turning off the protection switch K1 when the BAT-and bat+ are connected reversely due to the conduction of the reverse connection protection module of the battery core under the condition that the battery core is charged or discharged normally.

Optionally, the cell reverse connection protection module comprises a fourth transistor and a second resistor; the protection switch comprises a gallium nitride transistor; the grid electrode of the fourth transistor is connected with one end of the second resistor; the other end of the second resistor is connected with a second negative terminal of the battery cell group; the drain electrode of the fourth transistor is connected with the grid electrode of the gallium nitride transistor; the source electrode of the fourth transistor is connected with the second positive terminal of the battery cell group; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; the second drain of the gallium nitride transistor is connected with the second negative terminal of the battery cell group.

In the embodiment of the present utility model, as shown in fig. 7, the cell reverse connection protection module may be composed of a fourth transistor Q4 and a second resistor R2, and the protection switch may be a gallium nitride transistor K1. The grid electrode of the Q4 is connected with one end of the R2, the other end of the R2 is connected with a second negative electrode terminal BAT-of the battery cell group, the drain electrode of the Q4 is connected with the grid electrode of the K1, the source electrode of the Q4 is connected with a second positive electrode terminal BAT+ of the battery cell group, the first drain electrode of the K1 is connected with a first negative electrode terminal PACK-of the battery cell group, and the second drain electrode of the K1 is connected with the second negative electrode terminal BAT-of the battery cell group.

In the embodiment of the utility model, a battery cell reverse connection protection module is formed by Q4 and R2, when the BAT-and BAT+ of the battery cell group are reversely connected, namely, the grid electrode of the Q4 is changed from the BAT-which is originally input into the BAT+, when the grid electrode of the Q4 is input into the BAT+, the Q4 is conducted, the grid electrode of the K1 is conducted with a branch circuit connected with the drain electrode of the Q4, namely, a third branch circuit formed by the K1, the Q4 and R2 is conducted, the potential of the grid electrode of the protection switch K1 is directly pulled down to the BAT+, and the protection switch K1 is controlled to be turned off, so that the protection of a circuit is realized.

Optionally, the cell protection circuit further includes: an overvoltage clamping protection module; the overvoltage clamping protection module comprises a fourth branch and a fifth branch; the fourth branch consists of a second diode, a third diode and a first voltage stabilizing diode; the fifth branch consists of a fourth diode, a fifth diode and a second zener diode; the switch driving module comprises a first transistor and a second transistor; the protection switch is a gallium nitride transistor; the cathode of the first zener diode and the cathode of the first zener diode are respectively connected with the drain electrode of the second transistor and the branch where the grid electrode of the gallium nitride transistor is positioned; the anode of the first voltage stabilizing diode is connected with the anode of the second diode, the cathode of the second diode is connected with the anode of the third diode, and the cathode of the third diode is connected with the first drain electrode of the gallium nitride transistor; the anode of the second voltage stabilizing diode is connected with the anode of the fourth diode, the cathode of the fourth diode is connected with the anode of the fifth diode, and the cathode of the fifth diode is connected with the second drain electrode of the gallium nitride transistor.

In the embodiment of the present utility model, as shown in fig. 8, the protection switch is a gallium nitride transistor K1, the switch driving module includes a first transistor Q1 and a second transistor Q2, the cell protection circuit further includes an overvoltage clamping protection module, the overvoltage clamping protection module includes two branches, namely a fourth branch and a fifth branch, the fourth branch includes a first zener diode ZD1, a second diode D2, and a third diode D3, the fifth branch includes a second zener diode ZD2, a fourth diode D4, and a fifth diode D5, as in the connection manner in fig. 8, the cathode of D2 in the fourth branch is connected with the anode of D3, the anode of D2 is connected with the anode of ZD1, the cathode of ZD1 and the cathode of ZD2 are respectively connected with the drain of Q2 and the branch where the gate of K1 is located, and the cathode of D3 is connected with the first drain of K1. The cathode of D4 is connected with the anode of D5, the anode of D4 is connected with the anode of ZD2, and the cathode of D5 is connected with the second drain electrode of K1.

The switch driving module 10 includes a first transistor Q1 and a second transistor Q2, wherein the gates of the transistors Q1 are level signal control terminals, the source of the transistor Q1 is connected to the ground GND, the drain of the transistor Q1 is connected to the gate of the transistor Q2, the source of the transistor Q2 is connected to the positive dc+ of the DC power supply, and the drain of the transistor Q2 is connected to the gate of the transistor K1.

In the embodiment of the present utility model, the fourth branches ZD1, D2 and D3 and the fifth branches ZD2, D4 and D5 form an overvoltage clamping protection module, and when the protection switch K1 is driven to be turned on or off by the switch driving module 10, as shown in the circuit connection relationship shown in fig. 8, the driving voltage for controlling the on or off of the K1 can be within the preset voltage threshold through the fourth branch and/or the fifth branch.

It should be noted that, the preset voltage threshold may be determined according to an actual situation, which is not specifically limited in the present embodiment.

In the embodiment of the present utility model, as shown in fig. 9, the cell protection circuit further includes a first capacitor C1 and a second capacitor C2, one end of the sixth diode D6, one end of the C1 and one end of the C2 are connected to the cathode of the D6, the anode of the D6 is connected to the positive dc+ of the DC power supply, and the other end of the C1 and the other end of the C2 are connected to the negative of the DC power supply.

With continued reference to fig. 9, the cell protection circuit further includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9. One end of R3 is connected with DC+, one end of R4 is connected with the grid electrode of Q2, and the other end of R3 and the other end of R4 are connected with the drain electrode of Q1. One end of R5 is connected with the drain electrode of Q2, the other end of R5 is connected with one end of R6, and the other end of R6 is connected with the grid electrode of K1. One end of R7 is connected to the level signal control port GnD _en, the other end of R7 is connected to one end of R8, and the other end of R8 is connected to the ground GND. One end of R9 is connected with the second negative terminal of the battery cell group, and the other end of R9 is connected with the second drain electrode of K1.

In the embodiment of the present utility model, with continued reference to fig. 9, a first fuse F1 and a second fuse F2 are connected in parallel to a branch where the first positive terminal pack+ of the battery cell group is located, so as to protect a circuit.

Based on the above embodiments, the present utility model has the following technical advantages:

the gallium nitride transistor is used as one of third-generation semiconductor power components, has the characteristics of bidirectional double-drain single grid, high power, radiation resistance, smaller size, smaller internal resistance and the like, and solves the problems of low charging or discharging efficiency and large heating of the BMS based on the characteristics of the gallium nitride transistor. Because the MOS tube has a body diode, the traditional BMS protection adopts an N-channel MOS pair tube and a common source electrode to be connected, thereby realizing a load switch. According to the utility model, the gallium nitride transistor (GaN) is used for realizing the protection switch function of the BMS system, and the traditional double-tube protection mechanism is overturned, so that the PCB of the BMS system has smaller volume, higher efficiency, smaller heating and more stable performance.

In the scheme, because the gallium nitride transistor has very high driving requirement, the current flow direction can be known by the body diode in the traditional pair transistor MOS, and the GaN does not have the body diode, in order to ensure the stable and reliable operation of the gallium nitride transistor, an algorithm and a mechanism are needed to protect the gallium nitride transistor in different working states, such as discharging, charging and standby, namely, a gallium nitride driving circuit is designed through software and hardware collocation processing, and the gallium nitride driving circuit is used in a BMS protection system to realize the optimal gallium nitride driving scheme. The voltage can be controlled within a small range of values by voltage clamping, rapid discharge, reverse connection prevention, and the like.

In the scheme, a reverse connection prevention mechanism of the battery cell is further provided, so that the circuit can run more reliably and stably.

Based on the above embodiments, the present utility model provides a BMS system as shown in fig. 10. Wherein, pack+ is the first positive terminal, PACK-is the first negative terminal, bat+ is the second positive terminal, BAT-is the second negative terminal. F1 and F2 are fuses, and are used for ensuring the overcurrent protection of the system.

Cell Balancing circuit Cell Balancing provides equalization for the Cell units.

The analog front end AFE monitors the operating states of the individual cell units in the BMS system.

The MCU is a module for controlling the BMS system and is responsible for software protection, communication and the like.

The gallium nitride transistor is driven (GaN driven), and a reliable and stable driving voltage is provided for the gallium nitride transistor K1 in an independent control mode.

The DC-DC Buck provides a power supply system for the BMS.

Based on this, a lower internal resistance and smaller device size are achieved with one GaN transistor in this scheme as shown in fig. 11, compared to the conventional 2 unidirectional MOS as a bidirectional switch solution.

Based on the above embodiments, a workflow diagram of a BMS protection system is provided in this solution, as shown in fig. 12. In the operational principle flow diagram of the BMS system, the BMS protection system has a high-precision voltage detection circuit and a current detection circuit, which can be realized by a detection mechanism. And the voltage, charging or discharging current, temperature and other information of each cell unit can be detected through the AFE, so that the functions of overcharge, overdischarge, cell equalization, disconnection, low-voltage charge inhibition, discharge overcurrent, short circuit, charge overcurrent, over-temperature protection, discharge overcurrent protection, over-current delay protection and the like of the battery are realized. Wherein the logic processor may be implemented in the form of a software algorithm.

When the BMS of the traditional energy storage power supply fails, the output levels of CO and DO are forced to be reversed, and meanwhile, the charging and discharging MOS tube is turned off, so that charging and discharging are forbidden. The gallium nitride transistor in the scheme only needs to output one path of level, and is matched with software and hardware to realize the protection of the circuit. In a BMS system, a circuit is provided with a drive overvoltage clamping protection function, a reverse connection protection function and a drive quick discharge function, and through a software and hardware algorithm, gallium nitride is controlled to realize quick on and off, namely, the switching function of a gallium nitride transistor is realized.

Based on the foregoing embodiments, a battery management system provided in the present utility model includes any one of the foregoing embodiments of the battery protection circuit, and the composition of the battery protection circuit and the implementation principle thereof have been discussed in the foregoing embodiments, and reference may be made to the battery protection circuit in the foregoing embodiments, which is not described herein again.

In the embodiments provided in the present utility model, the above-described structural embodiments are merely illustrative, for example, the division of modules is merely a logic function division, and there may be other division manners in actual implementation, such as: multiple modules or components may be combined, or may be integrated into another system, or some features may be omitted, or not performed. In addition, the components shown or discussed are coupled to each other or directly.

The features disclosed in the several method or structure embodiments provided by the utility model can be arbitrarily combined without conflict to obtain new method embodiments or structure embodiments.

The above embodiments are only some embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present utility model, and the changes and substitutions should be covered in the protection scope of the present utility model. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.

Claims

1. A cell protection circuit, the circuit comprising: the device comprises a switch driving module, a protection switch and a battery cell group; wherein the battery cell group consists of at least one battery cell unit;

under the condition that the physical state information of any one of the battery core units in the battery core group is in an abnormal working state, the switch driving module is controlled to be turned off according to a first control signal received by the level signal control end, and the voltage flowing in the branch circuit of the protection switch is blocked so as to drive the protection switch to be turned off; when the protection switch is turned off, a charging or discharging loop formed by the first negative electrode terminal and the first positive electrode terminal of the battery cell group is disconnected, and the battery cell group is controlled to be in an uncharged or uncharged state.

2. The circuit of claim 1, wherein the switch drive module comprises a first transistor and a second transistor;

and under the condition that the physical state information of any one of the battery core units in the battery core group is in an abnormal working state, the first transistor is controlled to be turned off according to the first control signal received by the grid electrode of the first transistor, and the second transistor is turned off when the first transistor is turned off, so that the voltage flowing in the branch of the protection switch is blocked, and the protection switch is driven to be turned off.

3. The circuit of claim 2, wherein the protection switch comprises a gallium nitride transistor;

The source electrode of the first transistor is grounded; the drain electrode of the first transistor is connected with the grid electrode of the second transistor; the grid electrode of the first transistor is a level signal control end; the source electrode of the second transistor is connected with the positive electrode of the direct current power supply; the drain electrode of the second transistor is connected with the grid electrode of the gallium nitride transistor; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; a second drain electrode of the gallium nitride transistor is connected with a second negative terminal of the battery cell group;

under the condition that the physical state information of any one of the battery core units in the battery core group is in an abnormal working state, the first transistor is controlled to be turned off according to the first control signal received by the grid electrode of the first transistor, the second transistor is turned off when the first transistor is turned off, and the voltage flowing into the grid electrode of the gallium nitride transistor is blocked, so that the gallium nitride transistor is driven to be in a turn-off state.

4. The circuit of claim 1, wherein the circuit further comprises: a protection switch protection module; the switch driving module comprises a first transistor and a second transistor;

The first end of the protection switch protection module is connected with the first end of the protection switch; the second end of the protection switch protection module is grounded; the third end of the protection switch protection module is connected with a branch where the drain electrode of the first transistor and the grid electrode of the second transistor are located; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group;

when the switch driving module drives the protection switch to be turned on or turned off, the protection switch protection module outputs the current on the branch where the drain electrodes of the protection switch and the second transistor are positioned to the grounding end.

5. The circuit of claim 4, wherein the protection switch protection module comprises a third transistor, a first diode, and a first resistor;

the source electrode of the third transistor is grounded; the drain electrode of the third transistor is connected with the cathode electrode of the first diode; the grid electrode of the third transistor is connected with the drain electrode of the first transistor and the branch where the grid electrode of the second transistor is positioned; the anode of the first diode is connected with one end of the first resistor; the other end of the first resistor is connected with the first end of the protection switch; the second end of the protection switch is connected with the first negative terminal of the battery cell group; the third end of the protection switch is connected with the second negative terminal of the battery cell group;

When the switch driving module drives the protection switch to be turned on or off, the current on the second branch where the drains of the protection switch and the second transistor are located is output to the ground terminal through the first branch consisting of the first resistor, the first diode and the third transistor.

6. The circuit of claim 1, wherein the circuit further comprises: the battery cell is reversely connected with the protection module; the protection switch is a gallium nitride transistor;

the first end of the battery cell reverse connection protection module is connected with the second negative terminal of the battery cell group; the second end of the cell reverse connection protection module is connected with the grid electrode of the gallium nitride transistor; the third end of the battery cell reverse connection protection module is connected with the second positive terminal of the battery cell group; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; a second drain electrode of the gallium nitride transistor is connected with a second negative terminal of the battery cell group;

and under the condition that the second negative electrode terminal of the battery cell group is reversely connected with the second positive electrode terminal of the battery cell group, the voltage flowing into the battery cell reverse connection protection module is reversed, so that the battery cell reverse connection protection module is conducted, the protection switch is conducted with a branch circuit formed by the battery cell reverse connection protection module, and the voltage flowing through the protection switch is regulated so as to control the protection switch to be turned off.

7. The circuit of claim 6, wherein the reverse cell protection module comprises a fourth transistor and a second resistor; the protection switch comprises a gallium nitride transistor;

the grid electrode of the fourth transistor is connected with one end of the second resistor; the other end of the second resistor is connected with a second negative terminal of the battery cell group; the drain electrode of the fourth transistor is connected with the grid electrode of the gallium nitride transistor; the source electrode of the fourth transistor is connected with the second positive electrode terminal of the battery cell group; the first drain electrode of the gallium nitride transistor is connected with the first negative terminal of the battery cell group; a second drain electrode of the gallium nitride transistor is connected with a second negative terminal of the battery cell group;

and under the condition that the second negative electrode terminal of the battery cell group is reversely connected with the second positive electrode terminal of the battery cell group, the voltage flowing in by the grid electrode of the fourth transistor is reversed, so that the fourth transistor is conducted, a third branch consisting of the protection switch, the fourth transistor and the second resistor is conducted, and the voltage flowing through the grid electrode of the gallium nitride transistor is regulated so as to control the protection switch to be turned off.

8. The circuit of claim 1, wherein the circuit further comprises: an overvoltage clamping protection module; the overvoltage clamping protection module comprises a fourth branch and a fifth branch; the fourth branch consists of a second diode, a third diode and a first voltage stabilizing diode; the fifth branch consists of a fourth diode, a fifth diode and a second zener diode; the switch driving module comprises a first transistor and a second transistor; the protection switch is a gallium nitride transistor;

The cathode of the first zener diode and the cathode of the first zener diode are respectively connected with the drain of the second transistor and the branch where the grid of the gallium nitride transistor is located; the anode of the first voltage stabilizing diode is connected with the anode of the second diode, the cathode of the second diode is connected with the anode of the third diode, and the cathode of the third diode is connected with the first drain electrode of the gallium nitride transistor; the anode of the second voltage stabilizing diode is connected with the anode of the fourth diode, the cathode of the fourth diode is connected with the anode of the fifth diode, and the cathode of the fifth diode is connected with the second drain electrode of the gallium nitride transistor;

when the switch driving module drives the protection switch to be turned on or turned off, the fourth branch and/or the fifth branch are used for controlling the on or off driving voltage of the gallium nitride transistor to be within a preset voltage threshold.

9. The circuit of claim 1, wherein the circuit comprises a plurality of capacitors,

under the condition that the physical state information of each cell unit in the cell group is in a normal working state, the switch driving module is controlled to be conducted according to a second control signal received by the level signal control end, and the protection switch is driven to be conducted through the voltage flowing in the branch circuit of the protection switch; when the protection switch is conducted, a charging or discharging loop formed by the first negative electrode terminal and the first positive electrode terminal of the battery cell group is conducted, and the battery cell group is controlled to be in a charging or discharging state.

10. A cell management system, characterized in that it comprises a cell protection circuit according to any one of claims 1-9.