CN113690965A

CN113690965A - Protection circuit and circuit board, battery management system and battery package

Info

Publication number: CN113690965A
Application number: CN202110912889.0A
Authority: CN
Inventors: 袁庆丰; 覃磊; 杜晓佳; 黄思林
Original assignee: Dongguan Poweramp Technology Ltd
Current assignee: Dongguan Poweramp Technology Ltd
Priority date: 2021-07-09
Filing date: 2021-08-10
Publication date: 2021-11-23

Abstract

The embodiment of the application discloses a protection circuit, a circuit board, a battery management system and a battery pack. The protection circuit comprises a fusing module, a switch module and a control unit, wherein the fusing module is used for being electrically connected with the battery cell module, the external equipment and the switch module respectively, the external equipment comprises electric equipment or charging equipment, the switch module is used for being electrically connected with the battery cell module, the external equipment and the control unit respectively, and the switch module is configured to be disconnected or closed according to a control signal output by the control unit. By the mode, the cost of the protection circuit can be reduced.

Description

Protection circuit and circuit board, battery management system and battery package

Technical Field

The present disclosure relates to electronic circuits, and particularly to a protection circuit, a circuit board, a battery management system and a battery pack.

Background

A Battery Management System (BMS), which is a System for managing a Battery, mainly aims to prevent the Battery from being overcharged and overdischarged, reduce safety risks, and improve the service life of the Battery. In a conventional design, when overcurrent, overvoltage or overtemperature occurs in a main circuit, the BMS may protect the battery by turning off a power switching tube and blowing a fuse.

Disclosure of Invention

In the process of implementing the embodiment of the present application, the inventors of the present application find that: at present, a power switch tube is equivalently connected with external equipment in series in a battery management system, the power switch tube cannot be normally disconnected due to the fact that current and time cannot meet disconnection conditions, and therefore the risk of failure in protection of a battery pack and the external equipment occurs.

The embodiment of the application aims to provide a protection circuit, a circuit board, a battery management system and a battery pack, and the cost of the protection circuit can be reduced.

To achieve the above object, in a first aspect, the present application provides a protection circuit including a fuse module, a switch module, and a control unit. The fusing module is used for being electrically connected with the battery cell module, the external equipment and the switch module respectively, wherein the external equipment comprises electric equipment or charging equipment. The switch module is used for being electrically connected with the battery cell module and the control unit respectively, and the switch module is configured to be opened or closed according to a control signal output by the control unit.

After external equipment and the battery cell module are connected to the protection circuit respectively, if abnormal conditions such as overcurrent, overvoltage or overtemperature occur in the main loop, the control unit can output a first control signal to control the switch unit in the switch module to be switched on in an off state so as to fuse the fusing module, and therefore the input voltage provided by the battery cell module is switched off, and the possibility of explosion of the battery cell module due to factors such as overcurrent, overvoltage or overtemperature can be reduced.

In an alternative, the fuse module includes a first fuse module, and the first fuse module includes two first fuse units. The switch module includes a first switch unit and a second switch unit. One first fuse unit is electrically connected with the battery cell module, the other first fuse unit is connected with external equipment, a connecting point between the two first fuse units is electrically connected with the first switch unit, and the second switch unit is arranged between the first fusing module and the battery cell module or between the first fusing module and the external equipment.

If the external equipment connected with the protection circuit is electric equipment, the control unit outputs a control signal to the first switch unit to close the first switch unit, so that the first fuse unit can be fused to disconnect the voltage provided by the battery cell module; if the external device connected to the protection circuit is a charging device, when the second switch unit is in a failure state without being controlled by the control unit and cannot be switched from on to off, the control unit outputs a control signal to the first switch unit to close the first switch unit and fuse the second first fuse unit so as to cut off the transmission voltage provided by the charging device. Therefore, the possibility of explosion of the battery cell module due to factors such as overcharge, overcurrent, overvoltage or overtemperature can be further reduced. Secondly, first switch unit is not in the main circuit of charging and discharging that electric core module and external equipment constitute, does not receive the interference of electric current or voltage in the main circuit of charging and discharging, only is driven by the control unit, and control accuracy is high.

In an optional manner, the fuse module includes a second fuse module and a third fuse module, the second fuse module includes a second fuse unit, and the third fuse module includes a third fuse unit. The switch module includes a first switch unit and a second switch unit. The second fuse unit is electrically connected with the battery cell module, the third fuse unit is electrically connected with external equipment, and the second fuse unit is connected with the third fuse unit in series through the second switch unit. The connecting point of the second fuse unit and the second switch unit is electrically connected with the first switch unit.

If the external equipment connected with the protection circuit is electric equipment, the control unit outputs a control signal to the first switch unit, so that the second fuse unit can be fused when the first switch unit is closed, and the voltage provided by the battery cell module is cut off; if the external device connected with the protection circuit is a charging device, when the second switch unit is in a failure state without being controlled by the control unit and cannot be switched from on to off, the control unit outputs a control signal to the first switch unit, and when the second switch unit is switched on, the third fuse unit can be fused to disconnect the voltage provided by the charging device. Therefore, the possibility of explosion of the battery cell module due to factors such as overcurrent, overvoltage or overtemperature can be further reduced. Secondly, first switch unit is not in the charge-discharge circuit that electric core module and external equipment constitute, does not receive the interference of electric current or voltage in the charge-discharge circuit, only is driven by the control unit, and control accuracy is high.

In an optional manner, at least one of the first fuse unit, the second fuse unit, and the third fuse unit includes a metal unit disposed on the circuit board.

In an optional manner, at least one fuse unit of the first fuse unit, the second fuse unit, and the third fuse unit includes: the fuse comprises a fuse and an insulating layer covering the fuse, wherein the insulating layer is formed by arranging an insulating material at the periphery of the fuse and solidifying the insulating material.

The fuse unit in the protection circuit adopts the insulating layer formed by the insulating material to replace a ceramic shell or a plastic shell of the fuse, so that the structure is simpler, and the cost is lower.

In an alternative mode, the fuse is fixedly connected to the circuit board, the insulating layer covers at least a part of the fuse, and the insulating layer is arranged on the fuse and the circuit board.

In an optional manner, the fuse unit further includes a first electrode and a second electrode. The first electrode and the second electrode are arranged on the circuit board, and the fuse is arranged between the first electrode and the second electrode.

In an optional manner, the protection circuit further comprises a current limiting module. The current limiting module is electrically connected with the fusing module and the switch module respectively.

In an alternative, the current limiting module includes a third resistor. The first end of the third resistor is electrically connected with the fusing module, and the second end of the third resistor is electrically connected with the switch module.

In an optional manner, the current limiting module further includes an inductor, and the inductor is connected in series with the third resistor.

In an optional mode, the first switch unit is respectively connected with the positive electrode of the battery cell module, the control unit and the negative electrode of the battery cell module, wherein the first switch unit is electrically connected with the negative electrode of any battery cell in the battery cell module.

In an alternative mode, the first switching unit includes a first switching tube, and the first switching tube includes two transistors. The first terminals of the two transistors are electrically connected, and the second terminals of the two transistors are electrically connected. The first end of at least one transistor is electrically connected with the control unit, the third end of one transistor is electrically connected with the positive electrode of the battery cell module, and the third end of the other transistor is electrically connected with the negative electrode of any battery cell in the battery cell module.

In the two transistors, no matter which transistor has the third terminal at a high level, the two transistors can be conducted under the driving of the control unit outputting the first control signal, i.e. the first switch tube can be conducted in two directions. Therefore, no matter the battery cell module is in the charging process or the discharging process, when overcurrent, overcharge and overvoltage occur or when the temperature is too high, the control unit can control the two transistors to be conducted by applying driving voltage to the first end of any transistor, so that the fusing module is rapidly fused due to short circuit, and the possibility of explosion of the battery cell module due to the overcharge, the overcurrent, the overvoltage or the over-temperature can be reduced. And, first switch tube simple structure need not complicated connection structure and can realize two-way electrically conductive.

In an alternative mode, the first switch unit includes a fourth switch tube and a fifth switch tube. The first end of fourth switch tube and/or the first end of fifth switch tube are connected with the control unit electricity, and the second end of fourth switch tube is connected with the positive pole of electric core module, and the third end of fourth switch tube is connected with the third end of fifth switch tube, and the second end of fifth switch tube is connected with the negative pole electricity of arbitrary electric core in the electric core module.

In an alternative mode, the first switching unit includes a sixth switching tube and a first diode. The first end and the control unit electricity of sixth switch tube are connected, and the second end and the positive pole of first diode of sixth switch tube are connected, and the third end and the anodal of electric core module of sixth switch tube are connected, and the negative pole of arbitrary electric core electricity in the negative pole and the electric core module of first diode are connected.

In an optional manner, the first switching unit includes N seventh switching tubes connected in parallel, where N is a positive integer greater than 1. The first end and the control unit of seventh switch tube are connected, and the second end and the negative pole electricity of arbitrary electric core in the electric core module of seventh switch tube are connected, and the third end and the anodal of electric core module of seventh switch tube are connected.

In an alternative mode, the second switching unit includes a second switching tube and a third switching tube. The first end of the second switch tube is electrically connected with the control unit, the second end of the second switch tube is electrically connected with the second end of the third switch tube, the third end of the second switch tube is electrically connected with the battery cell module, the first end of the third switch tube is electrically connected with the control unit, and the third end of the third switch tube is electrically connected with external equipment.

In an optional manner, the protection circuit further comprises a detection module. The detection module is used for being electrically connected with the battery cell module and the external equipment respectively, and is also electrically connected with the control unit. The detection module detects current for detecting the protection circuit.

In an alternative form, the detection module includes a shunt electrically connected to the control unit. The first end of shunt and the negative pole electricity of electric core module are connected, and the second end of shunt and external equipment's negative pole electricity are connected.

In a second aspect, the present application provides a circuit board comprising a substrate and the protection circuit of the first aspect. Wherein, the protection circuit is arranged on the substrate.

In a third aspect, the present application provides a battery management system comprising a circuit board as in the second aspect.

In a fourth aspect, the present application provides a battery pack, which includes a battery cell module and the battery management system as in the third aspect. Wherein, battery management system is connected with electric core module electricity, and electric core module includes at least one electricity core.

In a fifth aspect, the present application provides an electric device, comprising a load and the battery pack as in the fourth aspect. Wherein, the battery package is used for supplying power for the load.

One or more embodiments of the present application include the following advantageous effects: the application provides a protection circuit includes fusing module, switch module and the control unit, and fusing module is connected with electric core module, external equipment and switch module electricity respectively, and switch module is connected with electric core module electricity, and switch module is controlled by the control unit. Under the normal condition, first switch module among the switch module keeps the disconnection, when the electricity core module takes place overcharge, overcurrent, overvoltage or when unusual such as excess temperature, the switch unit that keeps the disconnection among the control unit control switch module under the normal condition is closed to make the fusing module take place the fusing because of the short circuit, and then the connection of disconnection electricity core module and external equipment, reducible electricity core module takes place the possibility of blasting because of factors such as excess charge, overcurrent, overvoltage or excess temperature. And the fuse unit in the fusing module comprises a fuse and an insulating layer coated on the fuse, and compared with the fuse adopting a ceramic shell or a plastic shell, the fuse unit is simpler in structure and lower in cost. Moreover, the switch unit which is kept disconnected in the switch module under the normal condition is not in a charge-discharge loop formed by the battery cell module and the external equipment, is not interfered by current or voltage in the charge-discharge loop, is only driven by the control unit, and is high in control accuracy. In addition, in the two transistors, no matter which transistor has the third terminal at the high level, the two transistors can be conducted under the driving of the first control signal output by the control unit, namely, the first switch tube can be conducted in two directions. Therefore, no matter the battery cell module is in the charging process or the discharging process, when overvoltage, overcurrent and overcharge occur or when the temperature is too high, the control unit can apply driving voltage to the first end of any transistor to control the conduction of the two transistors, so that the protection circuit is communicated, namely, the fusing module is rapidly fused, and the possibility of explosion of the battery cell module due to abnormal conditions such as overcurrent, overvoltage or overtemperature is reduced. And, first switch tube simple structure need not complicated connection structure and can realize two-way electrically conductive.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

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

fig. 2 is a schematic circuit structure diagram of a protection circuit according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of a first fuse unit according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of a first fuse unit according to another embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a first switching tube according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of a protection circuit according to another embodiment of the present application;

fig. 7 is a schematic structural diagram of a protection circuit according to another embodiment of the present application;

fig. 8 is a schematic structural diagram of a protection circuit according to another embodiment of the present application;

fig. 9 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 10 is a schematic structural diagram of a circuit board according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a protection circuit according to another embodiment of the present application;

fig. 12 is a schematic structural diagram of a protection circuit according to another embodiment of the present application;

fig. 13 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 14 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 15 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 16 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 17 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 18 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 19 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 20 is a schematic circuit diagram of a protection circuit according to another embodiment of the present application;

fig. 21 is a schematic structural diagram of a protection circuit according to yet another embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a protection circuit according to an embodiment of the present disclosure. As shown in fig. 1, the protection circuit 100 includes a first fuse unit 10, a first switch unit 20, and a control unit 30.

The first end of the first fuse unit 10 is electrically connected to the first end of the battery cell module 200, the first fuse unit 10 is connected to the first switch unit 20 in series, that is, the second end of the first fuse unit 10 and the second end of the first switch unit 20 are connected to the first connection point P1, the third end of the first switch unit 20 is electrically connected to the second end of the battery cell module 200 and the external device 300 at the second connection point P2, and the first end of the first switch unit 20 is electrically connected to the control unit 30.

The battery cell module 200 may include only one battery cell, or at least two battery cells connected in series and/or in parallel. The external device 300 includes a power consumption device or a charging device.

Specifically, the first switch unit 20 is controlled by the control unit 30, and is opened and closed according to a first control signal output by the control unit 30. Under normal circumstances, the first switch unit 20 remains disconnected, and the battery cell module 200 is normally connected to the external device 300. When abnormal conditions such as overcurrent, overvoltage or over-temperature occur, the control unit 30 controls the first switch unit 20 to be closed, the first fusing unit 10, the first switch unit 20 and the battery cell module 200 form a loop, the first fusing unit 10 is fused due to a short circuit, so as to cut off the connection between the battery cell module 200 and the external device 300, and the possibility of explosion of the battery cell module 200 due to factors such as overcurrent, overvoltage or over-temperature can be reduced.

Referring to fig. 2 and 3, the first fuse unit 10 includes a first fuse 11 and a first insulating layer 12 covering the first fuse 11, wherein the first insulating layer 12 is formed by disposing an insulating material around the first fuse 11 and curing the insulating material.

It is understood that the first fuse 11 may be soldered on the circuit board, and then an insulating material may be applied to the periphery of the first fuse 11, such as the insulating material is coated on the surface of the first fuse 11, and after the insulating material is cured, the first insulating layer 12 is formed. The first insulating layer 12 covers at least a part of the first fuse 11, for example, as shown in fig. 3, the first insulating layer 12 covers the entire structure of the first fuse 11, which is beneficial to better protecting the first fuse 11 and reducing damage to the fuse 21 caused by other foreign objects. The first insulating layer 12 also serves to bond the first fuse 11 to the circuit board, so that the first fuse 11 can be more firmly fixed to the circuit board, which is beneficial to reducing the separation of the first fuse 11 from the circuit board.

In the related art, a fuse is commonly used for protection, and the fuse includes a fuse and a housing for supporting and connecting the fuse. The housing is usually a ceramic housing or a plastic housing. In the present application, the first fuse unit 10 for protection includes a first fuse wire 11 and a first insulating layer 12, and the first insulating layer 12 has a simpler structure and a lower cost compared to a ceramic case or a plastic case, which is helpful for improving market competitiveness.

It will be appreciated that the first insulating layer 12 may take on different shapes due to the different manner of applying the insulating material on the first fuse 11. In the embodiment shown in fig. 3, the first fuse 11 has a linear structure, but in other embodiments, the first fuse 11 may have other structures, such as an S-shaped structure or a spiral structure, and the like, which is not limited herein.

In one embodiment, as shown in fig. 4, the first fuse unit 10 further includes a first electrode 13 and a second electrode 14. Wherein, the electrode refers to a component in an electronic or electrical device and equipment and is used as two ends for inputting or outputting current in a conductive medium (solid, gas, vacuum or electrolyte solution).

Specifically, the first electrode 13 and the second electrode 14 are also soldered on the circuit board, and the first fuse 11 is disposed between the first electrode 13 and the second electrode 14. The first electrode 13 and the second electrode 14 may have a circular, square, or annular structure, and the first electrode 13 and the second electrode 14 may be the same or different, for example, as shown in fig. 4, the first electrode 13 and the second electrode 14 are both the same annular structure.

The first electrode 13 and the second electrode 14 may be made of metal, and may be used as the first electrode 13 and the second electrode 14 as long as the process of exchanging electrons is achieved.

In one embodiment, there is a gap between the first fuse 11 and the circuit board, and the insulating material can cover the gap between the first fuse 11 and the circuit board during the process of coating the first fuse 11 with the insulating material. The first insulating layer 22 formed by curing the insulating material is at least partially disposed in a gap between the first fuse 11 and the circuit board, so as to reduce the occurrence of abnormal situations such as burning, explosion and carbonization of the circuit board caused by explosion when the first fuse 11 is fused, and protect the circuit board. For example, when the circuit board is horizontally disposed, the first fuse 11 is soldered along the vertical direction of the circuit board and at a position spaced from the circuit board by 0-2mm, so that the gap between the first fuse 11 and the circuit board is greater than 0 and less than or equal to 2 mm.

Optionally, the first fuse unit 10 includes at least one air bubble disposed in the first insulating layer 12, and oxygen in the air helps the first fuse 11 to be blown faster. In another embodiment, the air bubble is formed between the first fuse 11 and the first insulating layer 12, which can further improve the fusing of the fuse 21.

In one embodiment, referring to fig. 2 again, the first switch unit 20 includes a first switch Q1 (in fig. 2, the NMOS transistor Q1), and referring to fig. 5 together, fig. 5 is a specific structure of the NMOS transistor Q1 provided by the present application.

The gate of the NMOS transistor Q1 is the first end of the first switch transistor, the source of the NMOS transistor Q1 is the second end of the first switch transistor, and the drain of the NMOS transistor Q1 is the third end of the first switch transistor.

As shown in fig. 5, the NMOS transistor Q1 includes a transistor Q1A and a transistor Q1B, and the transistor Q1A is the same as the transistor Q1B. The transistor Q1A and the transistor Q1B each include a semiconductor substrate 21, a source 22, a drain 23, an insulating layer 24, and a gate 25, wherein the source 22 and the drain 23 are disposed on the semiconductor substrate 21 at an interval and are respectively connected to the semiconductor substrate 21, the insulating layer 24 is disposed on the semiconductor substrate 21 and is located between the source 22 and the drain 23, and the gate 25 is disposed on the insulating layer 24 and is respectively insulated from the source 21 and the drain 22.

The semiconductor substrate 21 is formed of a semiconductor material, which may include amorphous silicon, polysilicon, an organic material, a metal oxide, or amorphous indium gallium zinc oxide. The conductivity of the semiconductor material is between that of a conductor and an insulator, so that the semiconductor substrate 21 has no conductivity without being triggered by an external condition, but when electrons or holes inside the semiconductor substrate 21 are shifted by an electric field under a certain condition, for example, in an electric field environment, the concentration of electrons or holes in a central region of the semiconductor substrate 21 is increased, so that the semiconductor substrate 21 has conductivity.

Wherein the drain 23 and the source 22 are formed of a conductive material, which may include a metal, such as aluminum, molybdenum, tungsten, chromium, a button, or a combination thereof. The drain 23 and the source 22 are disposed on the semiconductor substrate 21 at intervals and electrically connected to the semiconductor substrate 21, respectively. In some embodiments, the source 22 and the drain 23 may be directly connected to the semiconductor substrate 21, and when the semiconductor substrate 21 has conductivity in a region adjacent to the source 22 and the drain 23 under an electric field, the source 22 and the drain 23 may be electrically connected to the semiconductor substrate 21, respectively, based on the source 22 and the drain 23 also having conductivity. In order to increase the conductivity between the metal and the semiconductor, in some embodiments, two spaced apart highly doped regions 26 (i.e., N + regions) may be fabricated on the semiconductor, and the impurity in the highly doped regions 26 may be an N-type impurity, so that there are a large number of electron sources in the highly doped regions 26 that provide free electrons for current flow, and metal electrodes are respectively led out from the two highly doped regions 26 as the source 22 and the drain 23, i.e., so that the source 22 and the drain 23 are respectively indirectly connected to the semiconductor substrate 21. When the semiconductor substrate 21 has conductivity in a portion between the two highly doped regions 26 under an electric field, the conductivity is higher than that of the semiconductor based on the two highly doped regions 26, thereby enabling the source electrode 22 and the drain electrode 23 to be electrically connected.

The insulating layer 24 is made of an insulating material, and the insulating material may include silicon oxide, aluminum oxide, or the like. An insulating layer 24 is disposed on the semiconductor substrate 21 between the source electrode 22 and the drain electrode 23, and the insulating layer 24 is used to insulate the gate electrode 25 from the semiconductor substrate 21.

Wherein the gate 25 is formed of a conductive material, which may include a metal, such as aluminum, molybdenum, tungsten, chromium, a button, or a combination thereof.

Based on the structure of the transistor, the control unit 30 applies a positive voltage to the gate 25 to generate an electric field between the semiconductor substrate 21 and the gate 25, and under the action of the electric field, electrons in the semiconductor substrate 21 move toward the gate 25, and under the blocking action of the insulating layer 24, the electrons are collected on the surface layer of the semiconductor substrate 21 close to the insulating layer 24, thereby forming a conductive channel. It is understood that the region where the conductive channel is located is referred to as a channel region 27, the shape and size of the channel region 27 are related to the shape and size of the gate 25, and the channel region 27 is located on the surface layer of the semiconductor substrate 21 close to the insulating layer 24 and within the projection of the gate 25 relative to the semiconductor substrate 21. Since the channel region 27 is made conductive by the conductive channel formed by the convergence of the electrons, when a potential difference exists between the source 22 and the drain 23, the electrons in the channel region 27 flow under the action of the potential difference, and a current is generated.

In addition, in this embodiment, the transistor Q1A is electrically connected to the drain of the transistor Q1B, and the transistor Q1A is electrically connected to the gate of the transistor Q1B and to the control unit 30. The source of one of the transistors Q1A and Q1B is electrically connected to the first connection point P1, i.e., the positive electrode B + of the cell module 200, and the source of the other transistor is electrically connected to the second connection point P2, i.e., the negative electrode B-of the cell module 200. For example, the source of the transistor Q1A is electrically connected to the first connection point P1, and the source of the transistor Q1B is electrically connected to the second connection point P2. As can be seen, under the action of the battery cell module 200, a potential difference is formed between the source of the transistor Q1A and the source of the transistor Q1B. Because the two gates 25 of the two transistors are electrically connected and a positive voltage is applied to any one of the gates 25 or the connection line of the two gates 25, the two gates 25 can be controlled to form an electric field, and since the drains 23 of the two transistors are electrically connected, the potentials of the two drains 23 are the same, so that when one transistor is turned on, the other transistor is also turned on at the same time. In addition, any one of the two source electrodes 22 is at a high potential, and the other source electrode 22 is at a low potential, and both the two source electrodes 22 can be conducted under the driving voltage of the gate electrode 25, that is, the two-way conduction is realized, so that the control requirements in the charging and discharging processes of the battery cell module 200 are met.

For example, if the external device 300 is an electrical device, during the discharging process, the positive electrode potential of the cell module 200 is higher than the negative electrode potential, the source 22 of the transistor (assumed to be the transistor Q1A) near the positive electrode of the cell module 200 is at a high potential, and the source 22 of the transistor (assumed to be the transistor Q1B) near the negative electrode of the cell module 200 is at a low potential. When the transistor Q1A is turned on, the drain 23 of the transistor Q1A is raised in potential, so that a potential difference is also formed between the drain 23 and the source 22 of the transistor Q1B, and the transistor Q1B is also turned on. If the external device 300 is a charging device, during the charging process, the negative electrode potential of the cell module 200 is higher than the positive electrode potential, the source 22 of the transistor Q1A is at the low potential, and the source 22 of the transistor Q1B is at the high potential, when the transistor Q1B is turned on, the potential of the drain 23 of the transistor Q1B is raised, so that a potential difference is formed between the drain 23 and the source 22 of the transistor Q1A, and the transistor Q1A is also turned on.

In some embodiments, the connection between the two gates 25 may be a wire connection, or a connection through a conductive channel filled with a conductive substance such as a conductive paste. In some embodiments, the two drains 23 may also be connected by a wire, or a conductive channel filled with a conductive substance such as conductive paste. It will be appreciated that in some embodiments, two drains 23 may also be contacted adjacent to form a unitary body, i.e. equivalent to two transistors sharing a single drain 23.

From the above, the NMOS transistor Q1 has a simple structure, and bidirectional conduction can be achieved without a complicated connection structure. Whether the cell module 200 is in the charging process or the discharging process, when overcurrent, overvoltage, overcharge or over-high temperature occurs, the control unit 30 can apply the driving voltage to the gate 25 to control the transistor Q1A to be conducted with the transistor Q1B, so as to realize the secondary protection process, i.e. the first fusing unit 10 is rapidly fused, thereby reducing the possibility of explosion of the cell module 200 due to overcurrent, overvoltage or over-temperature.

In some embodiments, the material of the semiconductor substrate comprises silicon carbide. The silicon carbide has unique electrical properties of high critical field, high bulk mobility, high saturation velocity and the like. Particularly, the high critical field enables a transistor with silicon carbide as a substrate to have higher doping concentration and thinner drift layer thickness compared with a transistor with silicon as a substrate under the same voltage, thereby realizing lower on-resistance and higher electron mobility. The electron mobility is a physical quantity used in solid physics for describing the degree of speed of electrons in a metal or a semiconductor moving under the action of an electric field. Based on that carborundum itself has higher electron mobility, under the electric field effect, the inside electron of carborundum can the rapid draing, collects in the channel region, forms higher electric current to, carborundum can not be because of the heavy current punctures, and then, makes the transistor and the switch tube that constitutes by two transistors have the ability of nai heavy current.

In this embodiment, silicon carbide is used as the semiconductor substrate, and the silicon carbide itself has high electron mobility, so that the transistor and the first switching tube composed of two transistors have the capability of withstanding a large current, for example, 300A current for 2-5 seconds, so as to meet the current and time specified by the fuse condition of the first switching tube. Furthermore, the stability of the first switch tube is good, and the probability of damage of the first switch tube due to large current can be reduced.

In some embodiments, the material of the insulating layer in the transistor comprises silicon nitride. Silicon nitride has a high dielectric constant (the dielectric constant is in a range of 6-9), and the insulating layer of the conventional transistor is made of silicon dioxide, which has a dielectric constant of only about 4.2, so that the transistor has a low threshold voltage compared with the conventional transistor which uses silicon nitride as the insulating layer.

In this embodiment, a material with a high dielectric constant is used as the insulating layer, which can effectively increase the capacitance formed between the gate and the semiconductor substrate, and reduce the threshold voltage, so that the threshold voltage is less than or equal to the maximum voltage signal that can be output by the controller, i.e., the first switch tube can be directly controlled by the control unit 30, and no additional level shift circuit is needed, thereby simplifying the circuit. For example, the maximum voltage output by the control unit 30 is 3.3V, and then the dielectric constant of the material of the insulating layer in the transistor is set to 6-9, so that the threshold voltage of the first switch tube can be less than or equal to 3.3V, that is, the first switch tube can be directly controlled by the control unit 30.

It should be noted that the hardware configuration of the protection circuit 100 as shown in fig. 1 is only one example, and that the protection circuit 100 may have more or less components than those shown in the figure, may combine two or more components, or may have a different configuration of components, and that the various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software including one or more signal processing and/or application specific integrated circuits.

For example, as shown in fig. 6, the protection circuit 100 further includes a second switch unit 40 and a second fuse unit 50. The second fuse unit 50 is connected in series with the second switch unit 40, and the second fuse unit 50 is further configured to be electrically connected to the external device 300, wherein the second fuse unit 50 may be disposed between the third terminal of the second switch unit 40 and the external device 300 as shown in fig. 6, may be disposed between the first connection point P1 and the second terminal of the second switch unit 40 as shown in fig. 7, and may be disposed between the second connection point P2 and the external device 300 as shown in fig. 8. A first end of the second switch unit 40 is connected to the control unit 30, a second end of the second switch unit 40 is used for electrically connecting to the battery cell module 200, and a third end of the second switch unit 40 is used for connecting to the external device 300.

Specifically, the second switch unit 40 is controlled by the control unit 30, and is opened and closed according to a second control signal output by the control unit 30. Under normal conditions, the second switch unit 40 remains closed, and the battery cell module 200 is normally connected to the external device 300. When abnormal conditions such as overcurrent, overvoltage or over-temperature occur, the control unit 30 controls the second switch unit 40 to be disconnected to cut off the connection between the battery cell module 200 and the external device 300, so that the possibility of explosion of the battery cell module due to factors such as overcurrent, overvoltage or over-temperature can be reduced.

In one embodiment, referring to fig. 9 in combination with fig. 6, the second switch unit 40 includes a second switch Q2 (in fig. 3, an NMOS transistor Q2) and a third switch Q3 (in fig. 3, a PMOS transistor Q3). The gate of the NMOS transistor Q2 is electrically connected to the control unit 30, the drain of the NMOS transistor Q2 is electrically connected to the battery cell module 200 through a first connection point P1, the source of the NMOS transistor Q2 is electrically connected to the source of the PMOS transistor Q3, the drain of the PMOS transistor Q3 is electrically connected to the external device 300 through an interface P +, and the gate of the PMOS transistor Q3 is electrically connected to the control unit 30.

The gate of the NMOS transistor Q2 is the first end of the second switch transistor, the source of the NMOS transistor Q2 is the second end of the second switch transistor, and the drain of the NMOS transistor Q2 is the third end of the second switch transistor.

The grid electrode of the PMOS tube Q3 is the first end of the third switching tube, the source electrode of the PMOS tube Q3 is the second end of the third switching tube, and the drain electrode of the PMOS tube Q3 is the third end of the third switching tube.

Under the normal working state, the NMOS transistor Q2 or the PMOS transistor Q3 is in a normally-off state. When an abnormal condition such as an overcurrent or an overvoltage occurs, the control unit 30 controls the NMOS transistor Q2 to be disconnected from the PMOS transistor Q3.

However, in practical applications, the maximum current that can be disconnected when the NMOS transistor Q2 and the PMOS transistor Q3 are driven may be smaller than the current in the power main loop when a fault occurs, so that the NMOS transistor Q2 and the PMOS transistor Q3 may not be normally disconnected and still remain connected. Meanwhile, if the interface P + and the interface P-are connected to the electrical equipment (i.e., a load), since the load consumes electric energy, the actual current in the circuit may not reach the current required for fusing the fuse, so that the fuse is not fused, and then there may be an abnormality such as a continuous overcurrent and overvoltage, and a fire may occur in the cell module. In this case, the control unit 30 further controls the NMOS transistor Q1 to be turned on.

After the NMOS transistor Q1 is turned on, if the external device 300 connected to the interface P + and the interface P-is an electrical device, the source of the input voltage of the entire circuit is the battery cell module 200. Since the battery cell module 200, the first fuse unit 10 and the NMOS transistor Q1 form a loop, the first fuse unit 10 is fused due to a short circuit, and the electrical connection between the battery cell module 200 and other components is disconnected, that is, the input of the power supply voltage is stopped.

If the external device 300 connected to the interface P + and the interface P-is a charging device, the voltage source of the current includes both the cell module 200 and the external device 300. On one hand, a loop is formed by the battery cell module 200, the first fuse unit 10 and the NMOS transistor Q1, so that the first fuse unit 10 is fused due to a short circuit; on the other hand, a loop is formed by the NMOS transistor Q1, the NMOS transistor Q2, the PMOS transistor Q3, the second fuse unit 50, and the external device 300, so that the second fuse unit 20 is fused by a short circuit. Thereby disconnected electric connection of electric core module 200, external equipment 300 and other components in the lump, all played the guard action to electric core module 200, external equipment 300 and other components.

It can be seen that, when the circuit has an abnormality such as an overvoltage, an overcurrent, or an overtemperature, and the NMOS transistor Q2 and the PMOS transistor Q3 cannot be normally disconnected, the first fuse unit 10 can be fused or the first fuse unit 10 and the second fuse unit 20 can be fused by controlling the NMOS transistor Q1 to be turned on no matter whether the external device 300 is a consumer or a charging device, so as to cut off the voltage source of each component in time, and thus, the abnormality such as a continuous overcurrent, an overvoltage, or an overtemperature can be reduced, and the safety of the battery during charging and discharging can be improved.

In another embodiment, the second fuse unit 50 is made of the same material as the first fuse unit 10. That is, the second fuse unit 50 includes a second fuse 52 and a second insulating layer 51 covering the second fuse 52. The first end of the second fuse 52 is electrically connected to the external device 300 through the interface P +, and the second end of the second fuse 52 is electrically connected to the source of the PMOS transistor Q3. Moreover, in the above embodiment, the second fuse unit 50 may be further disposed between the first connection point P1 and the second switch unit 40, in which case, the first end of the second fuse 52 is electrically connected to the source of the NMOS transistor Q2, and the second end of the second fuse 52 is electrically connected to the first connection point P1. The second fuse unit 50 may also be disposed between the second connection point P2 and the external device 300, that is, a first end of the second fuse 52 is electrically connected to the first switch unit 20, and a second end of the second fuse 52 is electrically connected to the external device 300 through the interface P-.

Optionally, the second insulating layer 51 is formed by applying an insulating material to the periphery of the second fuse 52 and then curing, the second insulating layer 51 covers at least a part of the second fuse 52, and the second insulating layer 51 bonds the second fuse 51 to the circuit board.

Optionally, the second fuse unit 50 further includes a third electrode 53 and a fourth electrode 54, the third electrode 53 and the fourth electrode 54 are both soldered on the circuit board, and the second fuse 52 is disposed between the third electrode 53 and the fourth electrode 54.

Optionally, the second fusing unit 50 is fixedly connected to the circuit board, the second insulating layer 51 covers at least a portion of the second fuse 52, and the second insulating layer 51 bonds the second fuse 52 to the circuit board.

It should be understood that the second fuse unit 50 is similar to the first fuse unit 10 in the selection and practical application, and is within the scope easily understood by those skilled in the art, and will not be described herein.

In an embodiment, the protection circuit 100 further includes a first detection unit 60, where the first detection unit 60 is disposed between the negative electrode B of the battery cell module 200 and the interface P, that is, the first detection unit 60 is disposed between the negative electrode B of the battery cell module 200 and an external device.

The control unit 30 may obtain the current of the protection circuit 100, that is, the current between the negative electrode B-and the interface P-of the battery cell module 200, by detecting the voltage at the two ends of the first detection unit 60. Furthermore, if the control unit 30 has not output the second control signal to the second switch unit 40, that is, if the control unit 30 detects that the current between the cathode B-and the interface P-of the battery cell module 200 is greater than the first current threshold through the first detection unit 60, it is determined that the primary protection needs to be performed, and the control unit 30 outputs the second control signal to control the NMOS transistor Q2 to be disconnected from the PMOS transistor Q3.

If the control unit 30 has outputted the second control signal, a first time period is delayed, wherein the first time period is longer than the time period of the action of the NMOS transistor Q2 and the PMOS transistor Q3, i.e. the NMOS transistor Q2 and the PMOS transistor Q3 are disconnected within the first time period. However, if the control unit 30 can also detect that the current between the cathode B-and the interface P-of the battery cell module 200 is greater than the second current threshold through the first detection unit 60 after the first duration is over, and at this time, the NMOS transistor Q2 and/or the PMOS transistor Q3 may be abnormal and not disconnected, the control unit 30 performs secondary protection and outputs the first control signal to control the NMOS transistor Q1 to be closed.

The first current threshold and the second current threshold may be the same or different, and are not limited herein. In a preferred embodiment, if the NMOS transistor Q2 and the PMOS transistor Q3 are normally disconnected, and the current in the circuit is rapidly decreased to a smaller value, the second current threshold may be set smaller than the first current threshold to trigger the second protection more rapidly, so as to reduce the duration of abnormal phenomena due to over-current, over-voltage or over-temperature, and further protect the battery cell module 200 and various components in the circuit.

Optionally, the first detection unit 60 includes a first resistor R1, a first end of the first resistor R1 is electrically connected to the negative electrode B "of the battery cell module 200 and the control unit 30, and a second end of the first capacitor R1 is electrically connected to the control unit 30 and is electrically connected to the external device 300 through the interface P-.

By obtaining the voltage across the first resistor R1, the current flowing through the first resistor R1 can be obtained correspondingly, and the current is the current between the negative electrode B-and the interface P-of the battery cell module 200.

In another embodiment, the protection circuit further includes a second detecting unit 70, and the second detecting unit 70 is disposed between the second switching unit 40 (i.e., the PMOS transistor Q3) and the interface P +, i.e., the second detecting unit 70 is disposed between the PMOS transistor Q3 and the external device 300.

Wherein the control unit 30 may detect the current between the second switching unit 40 and the external device 300 through the second detection unit 70. Specifically, the current flowing through the second resistor R2, that is, the current between the second switching unit 40 and the external device 300, can also be obtained by obtaining the voltage of the second resistor R2.

As shown in fig. 10, fig. 10 is a schematic structural diagram of a circuit board provided in the present application. The circuit board 1000 includes the protection circuit 100 in any of the above embodiments, and a substrate 101.

Specifically, the protection circuit 100 is disposed on the substrate 101, and the protection circuit 100 may be soldered on the substrate 101 by a reflow soldering process, a wave soldering process, or a spot welding machine. In fig. 10, the substrate 101 is illustrated as a rectangular parallelepiped structure, but in other embodiments, the substrate 101 may also be other structures, such as a cylinder, and the like, which is not limited herein.

The embodiment of the application also provides a battery management system, which comprises the circuit board in any one of the above embodiments.

The embodiment of the application also provides a battery pack, and the battery pack comprises the battery cell module and the battery management system in any one of the above embodiments. The battery management system is electrically connected with the battery cell module, wherein the battery cell module comprises at least one battery cell.

The embodiment of the present application further provides an electric device, which includes a load and the battery pack in any one of the above embodiments, wherein the battery pack is used for supplying power to the load.

In one embodiment, as shown in fig. 11, the protection circuit 100 includes a fuse module 110, a switch module 120, and the control unit 30 in any of the above embodiments. The fusing module 110 is configured to be electrically connected to the battery cell module 200, the external device 300, and the switch module 120, respectively. The switch module 120 is configured to be connected to the battery cell module 200 and the control unit 30, respectively. In other embodiments, the switch module 120 is also used to electrically connect with the external device 300.

The switch module 120 includes a normally closed switch unit and a normally open switch unit. When an abnormality such as an overcurrent, an overvoltage, or an overtemperature occurs, the control unit 30 controls the normally open switching unit to be closed, so that the fuse module 100 is fused due to a short circuit. Both the connection between the battery cell module 200 and the protection circuit 100 and the connection between the external device 300 and the protection circuit 100 are disconnected, so that the voltage input possibly caused by the battery cell module 200 or the external device is cut off, and the possibility of explosion of the battery cell module 200 due to factors such as overcurrent, overvoltage or overtemperature can be reduced.

It is understood that the fusing module 110 or the switch module 120 may be disposed between the positive electrode of the battery cell module 200 and the positive electrode of the external device 300, or disposed between the negative electrode of the battery cell module 200 and the negative electrode of the external device 300.

In one embodiment, the switch module 120 includes the first switch unit 20 and the second switch unit 40 in any of the above embodiments. The switch module 120 is configured to be opened or closed according to a control signal output by the control unit 30, where the control signal includes a first control signal and a second control signal, the first control signal is used for controlling the first switch unit 20, and the second control signal is used for controlling the second switch unit 40.

In this embodiment, the fusing module 110 is disposed between the second switch unit 40 and the battery cell module 200. In another embodiment, as shown in fig. 12, the fusing module 110 may also be disposed between the second switch unit 40 and the external device 300.

Meanwhile, in the above embodiment, the first switch unit 20 includes the NMOS transistor Q1 as an example. In another embodiment, as shown in fig. 13, the first switch unit 20 includes a fourth switch Q4 (shown as an NMOS transistor Q4) and a fifth switch Q5 (shown as an NMOS transistor Q5). The gate of the NMOS transistor Q4 and/or the gate of the NMOS transistor Q5 are electrically connected to the control unit 30, the source of the NMOS transistor Q4 is connected to the positive electrode B + of the cell module 200, the drain of the NMOS transistor Q4 is connected to the drain of the NMOS transistor Q5, and the source of the NMOS transistor Q5 is electrically connected to the negative electrode of any cell in the cell module 200. In fig. 13, the gate of the NMOS transistor Q4 and the gate of the NMOS transistor Q5 are both electrically connected to the control unit 30, and the source of the NMOS transistor Q5 is electrically connected to the negative electrode of the third cell in the cell module 200 from top to bottom.

By adopting a structure in which two NMOS transistors share a drain electrode in series, a back-voltage prevention effect can be achieved in combination with a body diode existing in the NMOS transistor, and the withstand voltage of the first switching unit 20 can be improved.

It is understood that in this embodiment, the fourth switching tube and the fifth switching tube both use NMOS tubes, and in other embodiments, since the IGBT switching tube also has a body diode, a structure in which two IGBT switching tubes share a common drain in series may also be used.

Secondly, corresponding to different fuse units such as materials or models, the fuse units can be electrically connected with different cell cathodes in the cell module 200, so as to provide a suitable short-circuit current for the fuse units. It can be understood that, when a part of the cells in the cell module 200 forms a protection loop with the fuse module 110 and the first switch unit 20, a current in the protection loop is smaller than a current generated when the whole cell module forms a protection loop with the fuse module 110 and the first switch unit 20.

Meanwhile, through connecting the fuse unit with different cell cathodes in the cell module 200, when the fuse unit is fused, the voltage at two ends of the fuse unit is smaller than the total voltage of the cell module 200, so that the fuse unit with small rated voltage can meet the working requirement of high voltage. In an embodiment of the present application, the high voltage may be greater than 100V for the total voltage of the battery cell module 200.

In another embodiment, as shown in fig. 14, the first switch unit 20 includes a sixth switch Q6 (here, an NMOS Q6) and a first diode D1. The gate of the NMOS transistor Q6 is electrically connected to the control unit 30, the source of the NMOS transistor Q6 is connected to the anode of the first diode D1, the drain of the NMOS transistor Q6 is connected to the anode B + of the cell module 200, and the cathode of the first diode D1 is electrically connected to the cathode of any cell in the cell module 200.

When the external device 300 connected to the protection circuit 100 is a power-consuming device, if a power failure condition occurs (for example, the connection between the battery cell module 200 and the protection circuit 100 is disconnected), a large back voltage may be generated by the external device 300. For example, in one embodiment, where the external device 300 is a motor, since the motor is an inductive device, sudden power loss may cause the motor to generate a large back pressure, and possibly twice or more than the voltage provided by the protection circuit 100 to the motor. In this embodiment, the first diode D1 can protect the NMOS transistor Q6.

In another embodiment, the first switching unit 20 includes N seventh switching tubes connected in parallel, where N is a positive integer greater than 1. Alternatively, as shown in fig. 15, two NMOS transistors connected in parallel are taken as an example, and are respectively an NMOS transistor Q71 and an NMOS transistor Q72.

The gate of the NMOS transistor Q71 and the gate of the NMOS transistor Q72 are both connected to the control unit 30, and the gate of the NMOS transistor Q71 and the gate of the NMOS transistor Q72 may both be connected to the same port of the control unit 30, or may be connected to different ports of the control unit 30; the source electrode of the NMOS transistor Q71 is connected to the source electrode of the NMOS transistor Q72, and is connected to the negative electrode of any cell in the cell module 200; the drain of the NMOS transistor Q71 is connected to the drain of the NMOS transistor Q72, and to the anode of the cell module 200.

In this embodiment, a structure in which a plurality of NMOS transistors are connected in parallel is adopted, so that a higher pass current can be supported, and thus, when the current of the branch in which the first switch unit 20 is located is larger, the probability that the NMOS transistor is broken down can be reduced.

It should be understood that in other embodiments, the first switching unit 20 may also employ other types of switching control elements, such as gas discharge tubes, relays, or air switches.

In an embodiment, referring to fig. 11 again, the protection circuit 100 further includes a current limiting module 130. The current limiting module 130 is electrically connected to the switch module 120 and the fuse module 110, respectively.

When the fuse module 110 is blown, a large rush current, which may be several kiloamperes, may be generated in the protection circuit 100. The current limiting module 130 is arranged to limit current to reduce an impact current when the fuse module 110 is fused, so as to protect the first switch unit 20. Meanwhile, by reducing the current, a heat dissipation effect can be achieved to reduce the risk of damage to components in the protection circuit 100 due to overheating.

Optionally, referring to fig. 11 and fig. 16, the current limiting module 130 includes a third resistor R13, a first end of the third resistor R13 is electrically connected to the fuse module 110, and a second end of the third resistor R13 is electrically connected to the first switch unit 20. The third resistor R13 is connected in series in the circuit to limit the magnitude of the current of the branch, which is beneficial to reducing the current and further reducing the risk of burning out the component connected in series with the third resistor R13.

Optionally, current limiting module 130 further includes an inductor L13. The inductor L13 is connected in series with a third resistor R13. When the fuse module 110 fuses, the current can increase instantaneously, and the inductance L13 can hinder the change of the current, and can reduce the generation of the peak current, so that the current gradually increases, thereby reducing the impact brought by the current and being beneficial to protecting each component.

In an embodiment, referring to fig. 11 and 17 together, the blowing module 110 includes a first blowing module 111, and the first blowing module 111 includes a first fuse unit 1111 and a second first fuse unit 1112.

A first end of the first fuse unit 1111 is electrically connected to the positive electrode B + of the battery cell module 200, a second end of the first fuse unit 1111 and a first end of the second first fuse unit 1112 are electrically connected to a third connection point P3, a second end of the second first fuse unit 1112 is electrically connected to an interface P + (the interface P + is used for electrically connecting to the positive electrode of the external device 300) through the second switch unit 40, and the third connection point P3 is electrically connected to the first switch unit 20 through the current limiting module 130.

In a normal case, the first switching unit 20 is turned off. When an abnormality such as overcurrent, overvoltage, or overtemperature occurs, the control unit 30 controls the first switching unit 20 to close. On the one hand, a loop formed by the first fuse unit 1111, the current limiting module 130, the first switch unit 20 and the cell module may short-circuit the first fuse unit 1111 and blow. On the other hand, if the external device 300 is a charging device and the second switch unit 40 is not normally opened (i.e. kept closed), the second first fusing unit 1112, the current limiting module 130, the first switch unit 20 and the external device 300 form a loop to fuse the second first fusing unit 1112. Thereby, the electricity of electric core module 200, external equipment 300 and other components and parts has been broken in the lump, all plays the guard action to electric core module 200, external equipment 300 and other components and parts.

It is understood that, in this embodiment, the second switch unit 40 is disposed between the positive electrode B + of the battery cell module 200 and the positive electrode of the external device 300. In other embodiments, the second switch unit 20 may also be disposed between the negative electrode B-of the battery cell module 200 and the negative electrode of the external device 300 (not shown), and the working principle thereof is similar to that of the protection circuit shown in fig. 17, which is within the scope easily understood by those skilled in the art and will not be described herein again.

Meanwhile, in this embodiment, the second switching unit 40 is disposed between the first fuse module 111 and the external device 300. In another embodiment, if the structure of the first fuse module 111 shown in fig. 17 is applied to the circuit structure shown in fig. 12, an embodiment in which the second switch unit 40 is disposed between the first fuse module 111 and the battery cell module 200 can be obtained, and the working principle of the embodiment is similar to that of the circuit shown in fig. 17, which is within the scope easily understood by those skilled in the art and will not be described herein again.

In one embodiment, please refer to fig. 17 and 18 together, wherein fig. 18 illustrates an exemplary structure of the first fuse module 111. The first fuse unit 1111 and the second first fuse unit 1112 both include fuse structures, and when the first switch unit 20 is closed, the fuses of the two fuse structures are blown, so as to perform a protection function.

In an embodiment, referring to fig. 11 and 19, the fuse module 110 includes a second fuse module 112 and a third fuse module 113. The second fuse module 112 includes a second fuse unit 1121, and the third fuse module 113 includes a third fuse unit 1131.

A first end of the second fuse unit 1121 is electrically connected to the positive electrode B + of the battery cell module 200, a second end of the second fuse unit 1121 is electrically connected to a first end of the third fuse unit 1131 through the second switch unit 40, a second end of the third fuse unit 1131 is electrically connected to the interface P +, the second fuse unit 1121 and the second switch unit 40 are electrically connected to the fourth connection point P4, and the fourth connection point P4 is electrically connected to the first switch unit 20 through the current limiting module 130.

In a normal case, the first switching unit 20 is turned off. When an abnormality such as overcurrent, overvoltage, or overtemperature occurs, the control unit 30 controls the first switching unit 20 to close. Similarly, the second fuse unit 1121 and the third fuse unit 1131 can be blown, so that the electrical connection between the battery cell module 200 and the external device 300 and other components is broken, and the battery cell module 200, the external device 300 and other components are protected.

In another embodiment, the second switch unit 20 may also be disposed between the negative electrode B-of the battery cell module 200 and the negative electrode of the external device 300 (not shown in the figure), and in this embodiment, the operation principle of the second switch unit is similar to that of the protection circuit described in fig. 19, which is within the scope easily understood by those skilled in the art and is not described herein again.

It should be noted that, in the above embodiment, any one of the first fuse unit 1111, the second first fuse unit 1112, the second fuse unit 1121, and the third fuse unit 1131 may include the same material as the first fuse unit 10. For example, any of the fuse units may include a fuse and an insulating layer covering the fuse as shown in fig. 3. Also, the selection and practical application of any fuse unit may be similar to the first fuse unit 10.

In one embodiment, please refer to fig. 19 and fig. 20 together, wherein fig. 20 illustrates an exemplary structure of the second fuse unit 1121. The second fuse unit 1121 includes a fuse structure. When the first switching unit 20 is closed, the fuse in the fuse structure is blown due to a short circuit. In another embodiment, the third fuse unit 1131 may also include the same structure as the fuse structure in the second fuse unit 1121.

In an embodiment, any one of the first fuse unit 1111, the second first fuse unit 1112, the second fuse unit 1121, and the third fuse unit 1131 includes a metal unit disposed on the circuit board.

Alternatively, the metal unit may be copper, and when any one of the first fuse unit 1111, the second first fuse unit 1112, the second fuse unit 1121, and the third fuse unit 1131 is short-circuited, the copper fixed on the circuit board is blown out, so as to perform a protection function. The width of copper can be determined according to the current of the branch circuit where the copper is located.

It should be noted that the hardware configuration of the protection circuit 100 as shown in fig. 11 to 20 is only one example, and that the protection circuit 100 may have more or less components than those shown in the figures, may combine two or more components, or may have a different component configuration, and the various components shown in the figures may be implemented in hardware, software, or a combination of hardware and software including one or more signal processing and/or application specific integrated circuits.

For example, the protection circuit 100 in any of the above embodiments may further include a detection module, for example, the detection module is added to the circuit structure shown in fig. 11.

As shown in fig. 21, the detection module 140 is configured to be electrically connected to the battery cell module 200 and the external device 300, and the detection module 200 is further electrically connected to the control unit 30. The detection module detects a current for detecting the protection circuit 100.

Optionally, the detection module 140 includes a diverter 141. A first end of the shunt 141 is electrically connected to the negative electrode of the battery cell module 200, and a second end of the shunt 141 is electrically connected to the negative electrode of the external device 200. In an embodiment, the shunt 141 may be a resistor, and the shunt is achieved through the resistor, and the actual detection process is similar to that of the first resistor R1 or the second resistor R2 in the above embodiment, which is within the scope easily understood by those skilled in the art and will not be described herein again.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; within the context of the present application, where technical features in the above embodiments or in different embodiments can also be combined, the steps can be implemented in any order and there are many other variations of the different aspects of the present application as described above, which are not provided in detail for the sake of brevity; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A protection circuit, comprising:

the device comprises a fusing module, a switch module and a control unit;

the fusing module is used for being electrically connected with the battery cell module, external equipment and the switch module respectively, wherein the external equipment comprises electric equipment or charging equipment;

the switch module is used for being electrically connected with the battery cell module and the control unit respectively, and the switch module is configured to be opened or closed according to a control signal output by the control unit.

2. The protection circuit of claim 1,

the fusing module comprises a first fusing module which comprises two first fuse units;

the switch module comprises a first switch unit and a second switch unit;

one first fuse unit is electrically connected with the battery cell module, the other first fuse unit is connected with the external equipment, and a connecting point between the two first fuse units is electrically connected with the first switch unit;

the second switch unit is arranged between the first fusing module and the battery cell module or between the first fusing module and the external equipment.

3. The protection circuit of claim 1,

the fusing module comprises a second fusing module and a third fusing module, the second fusing module comprises a second fuse unit, and the third fusing module comprises a third fuse unit;

the switch module comprises a first switch unit and a second switch unit;

the second fuse unit is electrically connected with the battery cell module, the third fuse unit is electrically connected with the external equipment, the second fuse unit is connected with the third fuse unit in series through the second switch unit, and a connecting point of the second fuse unit and the second switch unit is electrically connected with the first switch unit.

4. The protection circuit according to claim 2 or 3,

at least one fuse unit of the first fuse unit, the second fuse unit and the third fuse unit comprises a metal unit arranged on a circuit board.

5. The protection circuit according to claim 2 or 3,

at least one fuse unit of the first fuse unit, the second fuse unit, and the third fuse unit includes: the fuse comprises a fuse wire and an insulating layer covering the fuse wire, wherein the insulating layer is formed by arranging an insulating material on the periphery of the fuse wire and solidifying the insulating material.

6. The protection circuit of claim 5,

the fuse wire is arranged on the circuit board, the insulating layer covers at least part of the structure of the fuse wire, and the insulating layer is arranged on the fuse wire and the circuit board.

7. The protection circuit of claim 6,

the fuse unit further comprises a first electrode and a second electrode;

the first electrode and the second electrode are arranged on the circuit board, and the fuse is arranged between the first electrode and the second electrode.

8. The protection circuit of claim 1,

the protection circuit further comprises a current limiting module;

the current limiting module is electrically connected with the fusing module and the switch module respectively.

9. The protection circuit of claim 8,

the current limiting module comprises a third resistor;

the first end of the third resistor is electrically connected with the fusing module, and the second end of the third resistor is electrically connected with the switch module.

10. The protection circuit of claim 9,

the current limiting module further comprises an inductor;

the inductor is connected in series with the third resistor.

11. The protection circuit according to claim 2 or 3,

the first switch unit is respectively connected with the positive electrode of the battery cell module, the control unit and the negative electrode of the battery cell module;

the first switch unit is electrically connected with the negative electrode of any battery cell in the battery cell module.

12. The protection circuit of claim 11,

the first switch unit comprises a first switch tube, and the first switch tube comprises two transistors;

the first ends of the two transistors are electrically connected, and the second ends of the two transistors are electrically connected; the first end of at least one transistor is electrically connected with the control unit, the third end of one transistor is electrically connected with the anode of the battery cell module, and the third end of the other transistor is electrically connected with the cathode of any battery cell in the battery cell module.

13. The protection circuit of claim 11,

the first switch unit comprises a fourth switch tube and a fifth switch tube;

the first end of the fourth switch tube and/or the first end of the fifth switch tube are electrically connected with the control unit, the second end of the fourth switch tube is connected with the positive electrode of the battery cell module, the third end of the fourth switch tube is connected with the third end of the fifth switch tube, and the second end of the fifth switch tube is electrically connected with the negative electrode of any battery cell in the battery cell module.

14. The protection circuit of claim 11,

the first switch unit comprises a sixth switch tube and a first diode;

the first end of the sixth switching tube is electrically connected with the control unit, the second end of the sixth switching tube is connected with the anode of the first diode, the third end of the sixth switching tube is connected with the anode of the battery cell module, and the cathode of the first diode is electrically connected with the cathode of any battery cell in the battery cell module.

15. The protection circuit of claim 11,

the first switch unit comprises N seventh switch tubes connected in parallel, wherein N is a positive integer greater than 1;

the first end of the seventh switch tube is connected with the control unit, the second end of the seventh switch tube is electrically connected with the negative electrode of any one battery cell in the battery cell module, and the third end of the seventh switch tube is connected with the positive electrode of the battery cell module.

16. The protection circuit according to claim 2 or 3,

the second switch unit comprises a second switch tube and a third switch tube;

the first end of the second switch tube is electrically connected with the control unit, the second end of the second switch tube is electrically connected with the second end of the third switch tube, the third end of the second switch tube is electrically connected with the battery cell module, the first end of the third switch tube is electrically connected with the control unit, and the third end of the third switch tube is electrically connected with the external equipment.

17. The protection circuit of claim 1,

the protection circuit further comprises a detection module;

the detection module is used for being electrically connected with the battery cell module and the external equipment respectively, and is also electrically connected with the control unit;

the detection module detects a current for detecting the protection circuit.

18. The protection circuit of claim 17,

the detection module comprises a current divider which is electrically connected with the control unit;

the first end of the shunt is electrically connected with the negative electrode of the battery cell module, and the second end of the shunt is electrically connected with the negative electrode of the external equipment.

19. A circuit board comprising a substrate and the protection circuit according to any one of claims 1 to 18;

the protection circuit is arranged on the substrate.

20. A battery management system comprising the circuit board of claim 19.

21. A battery pack comprising a cell module and the battery management system of claim 20, the battery management system electrically connected to the cell module, wherein the cell module comprises at least one cell.

22. An electrical device comprising a load and the battery pack of claim 21, the battery pack being configured to power the load.