Short-circuit protection circuit and method of battery pack, management system and electric equipment

Abstract

The invention discloses a short-circuit protection circuit and method of a battery pack, a management system and electric equipment. The protection circuit comprises at least one of a first short-circuit protection module, a second short-circuit protection module, a third short-circuit protection module and a fourth short-circuit protection module, wherein the first short-circuit protection module, the second short-circuit protection module, the third short-circuit protection module and the fourth short-circuit protection module are respectively used for being connected with a battery pack in series to form a charging and discharging loop; the first short-circuit protection module is used for cutting off the charging and discharging loop when the battery pack is short-circuited; at least one of the first short-circuit protection module, the second short-circuit protection module, the third short-circuit protection module and the fourth short-circuit protection module is used for cutting off a charging and discharging loop when the whole battery pack is short-circuited; and the third short-circuit protection module or / and the fourth short-circuit protection module is / are used for cutting off the charging and discharging loop when the electric equipment corresponding to the battery pack or the battery pack management system fails. And the short-circuit protection reliability and comprehensiveness of the battery pack can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a short-circuit protection circuit and method for a battery pack, a management system and electrical equipment. Background Art

[0002] The existing battery pack short-circuit protection circuit generally uses MOS tubes (Metal-Oxide Semiconductor FET, MOSFET). The upper limit of the short-circuit protection current of the MOS tube is small, within 1500A. When the short-circuit current is greater than 1500A, it cannot provide protection, and the MOS tube fails by breakdown, that is, the high-voltage circuit is the pathway, which makes the battery system insulated and has the risk of electric shock, and the battery cannot be repaired and used. In addition, when the battery pack of the battery pack itself is short-circuited, the existing protection circuit cannot provide protection. Finally, the existing protection circuit has a single protection mode and a low functional safety level. Summary of the invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a short-circuit protection circuit and method for a battery pack, a management system and an electrical device.

[0004] In a first aspect of the present invention, a short circuit protection circuit of a battery pack is provided, comprising: at least one short circuit protection module among a first short circuit protection module, a second short circuit protection module, a third short circuit protection module and a fourth short circuit protection module, wherein the first short circuit protection module, the second short circuit protection module, the third short circuit protection module and the fourth short circuit protection module are respectively used to be connected in series with a battery pack to form a charge and discharge circuit; Among them, the first short-circuit protection module is used to cut off the charging and discharging circuit when a short circuit occurs in the battery pack itself; at least one short-circuit protection module among the first short-circuit protection module, the second short-circuit protection module, the third short-circuit protection module and the fourth short-circuit protection module is used to cut off the charging and discharging circuit when a short circuit occurs in the battery pack as a whole, and the third short-circuit protection module and / or the fourth short-circuit protection module are also used to cut off the charging and discharging circuit when the electrical equipment corresponding to the battery pack or the battery pack management system fails.

[0005] In addition, the short-circuit protection circuit of the battery pack of the present invention may also have the following additional technical features: Preferably, the first short-circuit protection module comprises a first narrow-diameter metal member and a second narrow-diameter metal member, and the first narrow-diameter metal member and the second narrow-diameter metal member are respectively electrically connected to the positive electrode and the negative electrode of the battery pack and / or the battery module constituting the battery pack; The first narrow diameter metal member and the second narrow diameter metal member both include a first metal segment and a second metal segment connected, and a flow area at the connection between the first metal segment and the second metal segment is smaller than a flow area of ​​the first metal segment and a flow area of ​​the second metal segment.

[0006] Preferably, the width of the first metal segment and the second metal segment at a connection point is smaller than the width of the first metal segment, and smaller than the width of the second metal segment.

[0007] Preferably, the first metal segment is provided with a tab welding hole extending in the length direction, and a plurality of via holes are provided in the width direction at the connection between the first metal segment and the second metal segment.

[0008] Preferably, the second short-circuit protection module comprises a fuse, and the fuse is connected in series with the positive electrode or the negative electrode of the battery pack.

[0009] Preferably, the third short-circuit protection module includes a first charge and discharge unit, which is connected in series with the positive electrode or the negative electrode of the battery pack, and includes a discharge switch tube and a charge switch tube connected in series.

[0010] Preferably, the discharge switch tube is a first N-type MOS tube, the charge switch tube is a second N-type MOS tube, the source of the first N-type MOS tube is connected to the positive electrode of the battery pack, the drain of the first N-type MOS tube is connected to the drain of the second N-type MOS tube, and a first body diode is connected between the source and drain of the first N-type MOS tube; The source of the second N-type MOS tube is connected to the load, the gate of the second N-type MOS tube and the gate of the first N-type MOS tube are both connected to the controller, and a second body diode is connected between the source and drain of the second N-type MOS tube.

[0011] Preferably, the third short-circuit protection module also includes a second charge and discharge unit, which is connected in parallel with the first charge and discharge unit, and the second charge and discharge unit includes a first resistor and a P-type MOS tube connected in series, wherein a third body diode is connected between the source and the drain of the P-type MOS tube.

[0012] Preferably, the second charge and discharge unit further includes an anti-reverse diode, a positive terminal of the anti-reverse diode is connected to the P-type MOS tube, and a negative terminal of the anti-reverse diode is connected to the load.

[0013] Preferably, the fourth short circuit protection module includes a first fuse and / or a second fuse, wherein the first fuse and the second fuse are connected in parallel to form a first parallel circuit, and the first parallel circuit is connected in series with the positive electrode or the negative electrode of the battery pack.

[0014] Preferably, the first fuse is a two-terminal fuse, and the second fuse is a three-terminal fuse.

[0015] Preferably, the short-circuit protection circuit also includes a current detection module and a controller, the current detection module is used to detect the current information of the charging and discharging circuit, the signal output end of the current detection module is electrically connected to the signal input end of the controller, and the signal output end of the controller is electrically connected to the third short-circuit protection module and the fourth short-circuit protection module respectively.

[0016] Preferably, the current detection module includes a first current acquisition unit and / or a second current acquisition unit, wherein the first current acquisition unit and the second current acquisition unit are connected in series; The first current acquisition unit includes a first sampling resistor and an AFE chip connected in parallel; the second current acquisition unit includes a second sampling resistor and an OPA chip connected in parallel.

[0017] A second aspect of the present invention provides a short circuit protection method for a battery pack, comprising: Preset battery pack failure types, where the battery pack failure types include short circuit of the battery pack itself, short circuit of the entire battery pack, and failure of the power-consuming device corresponding to the battery pack or the battery pack management system; According to the fault type of the battery pack, at least one short-circuit protection module among the first short-circuit protection module, the second short-circuit protection module, the third short-circuit protection module and the fourth short-circuit protection module is triggered to cut off the charge and discharge circuit; wherein, When a short circuit occurs in the battery pack itself, the first short circuit protection module is triggered to cut off the charge and discharge circuit; When a short circuit occurs to the entire battery pack, at least one of the first short circuit protection module, the second short circuit protection module, the third short circuit protection module and the fourth short circuit protection module is triggered to cut off the charge and discharge circuit; When the power-consuming device corresponding to the battery pack or the battery pack management system fails, the third short-circuit protection module and / or the fourth short-circuit protection module are triggered to cut off the charge and discharge loop.

[0018] Preferably, if it is detected that the short-circuit current of the battery pack itself reaches a first current threshold range, the first short-circuit protection module is triggered to cut off the charge and discharge circuit; If it is detected that the short-circuit current of the charge-discharge loop formed by the battery pack reaches the second current threshold range or the third current threshold range, at least one of the first short-circuit protection module, the second short-circuit protection module, the third short-circuit protection module and the fourth short-circuit protection module is triggered to cut off the charge-discharge loop; wherein the second current threshold range is greater than the third current threshold range; If it is detected that the battery pack is thermally out of control or the electrical equipment corresponding to the battery pack collides, the third short-circuit protection module and / or the fourth short-circuit protection module are triggered to cut off the charge and discharge loop.

[0019] Preferably, the first current threshold range is 8000A~10KA, the second current threshold range is 1500A~10KA, and the third current threshold range is 500A~1500A.

[0020] Preferably, if it is detected that the short-circuit current of the battery pack itself reaches a first current threshold range, the first narrow-diameter metal member and / or the second narrow-diameter metal member are fused at the connection to cut off the charge and discharge circuit; If it is detected that the short-circuit current of the charge-discharge loop reaches a second current threshold range, at least one of the following operations is triggered: the first narrow-diameter metal part is melted at the connection, the second narrow-diameter metal part is melted at the connection, the fuse is melted, the two-terminal fuse is melted, and the three-terminal fuse is melted; If it is detected that the short-circuit current of the charge-discharge loop reaches a third current threshold range, at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge-discharge unit is disconnected, and the second charge-discharge unit is disconnected; If the battery pack is detected to be thermally out of control, at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge and discharge unit is disconnected, and the second charge and discharge unit is disconnected; If a collision is detected with the electrical equipment corresponding to the battery pack, at least one of the following operations is triggered: a two-terminal fuse is blown, a three-terminal fuse is blown, the first charge and discharge unit is disconnected, and the second charge and discharge unit is disconnected.

[0021] A third aspect of the present invention provides a battery pack, comprising the short-circuit protection circuit of the battery pack described in any embodiment of the present application.

[0022] A fourth aspect of the present invention provides a battery pack management system, comprising the battery pack and a load as described in any embodiment of the present application, wherein the short-circuit protection circuit is connected in series with the load to form a charge and discharge loop.

[0023] According to a fifth aspect of the present invention, there is provided an electrical device, which includes the short-circuit protection circuit of the battery pack described in any embodiment of the present application, or includes the battery pack of any embodiment of the present application, or includes the battery pack management system of any embodiment of the present application.

[0024] According to the short-circuit protection circuit and method, management system and electrical equipment of the battery pack provided by the present invention, the short-circuit protection circuit of the battery pack, the first short-circuit protection module, the second short-circuit protection module, the third short-circuit protection module and the fourth short-circuit protection module as independent short-circuit protection modes or multiple combined short-circuit protection modes, improve the safety level of the short-circuit protection of the battery pack, and further improve the safety of the battery pack; and can achieve full current protection, from the minimum fault current to the maximum short-circuit current (500A~10KA), can be protected, with the characteristics of good stability, strong reliability, comprehensiveness, wide protection current range, etc., and can be used for short-circuit protection of electrical equipment such as electric motorcycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 A schematic diagram of a short-circuit protection circuit for a battery pack provided in an embodiment of the present application; Figure 2 A structural diagram of a battery pack in which a short-circuit protection circuit provided in an embodiment of the present application is applied; Figure 3 for Figure 2 Installation position diagram of the first narrow diameter metal part and the second narrow diameter metal part; Figure 4 for Figure 3 The first narrow diameter metal part structure diagram; Figure 5 for Figure 4 The first narrow diameter metal part fusing principle diagram; Figure 6 A structural diagram of a fuse provided in an embodiment of the present application; Figure 7 A schematic diagram of a short-circuit protection circuit for a battery pack provided in an embodiment of the present application; Figure 8 for Figure 7 A parallel circuit diagram of the first charge-discharge unit and the second charge-discharge unit; Fig. 9 A diagram showing the installation positions of the first N-type MOS transistor and the second N-type MOS transistor on the protection board provided in an embodiment of the present application; Fig.10 A diagram showing the installation position of a three-terminal fuse on a protection board provided in an embodiment of the present application; Fig.11 for Fig.10 The three-terminal fuse structure diagram in; Fig.12 A flowchart of a short circuit protection method for a battery pack provided in an embodiment of the present application.

[0026] In the above picture: 10 battery pack; 11 battery group; 111 battery module; 12 connecting copper busbar; 20 first short circuit protection module; 21 first narrow diameter metal part; 210 first metal segment; 211 pole ear welding hole; 220 second metal segment; 221 via hole; 22 second narrow diameter metal part; 30 fuses; 40 third short circuit protection module; 41 first charge and discharge unit; 410 discharge switch tube; 4101 first N-type MOS tube; 4102 first body diode; 420 charge switch tube; 4201 second N-type MOS tube; 4202 second body diode; 42 second charge and discharge unit; 421 first resistor; 422 P-type MOS tube; 423 third body diode; 424 anti-reverse diode; 50 fourth short circuit protection module; 51 first fuse; 52 second fuse; 60 current detection module; 61 first current acquisition unit; 611 first sampling resistor; 612 AFE chip; 62 second current acquisition unit; 621 second sampling resistor; 622 OPA chip; 70 controller; 80 positive high voltage connector; 81 negative high voltage connector; 90 load; 100 protection board; 110 heating control module. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in this article refers to and includes any or all possible combinations of one or more associated listed items.

[0030] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be construed in an open, inclusive sense, ie, meaning "including, but not limited to."

[0031] In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" are intended to indicate that a specific feature, structure, material or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0032] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0033] At present, electric vehicles, such as electric motorcycles, are increasingly accepted by users and the public. The demand for long-range and high-rate charging and discharging by electric motorcycle owners has become increasingly urgent, and the core power source of electric motorcycles, such as battery packs, has been put forward design requirements for high voltage, large power, and high-current charging and discharging. Compared with the conventional current charging and discharging of the traditional voltage platform, the safety requirements for the battery pack of electric motorcycles have increased exponentially, mainly in four categories: electrical safety, short-circuit protection safety, mechanical safety, and thermal safety. Among them, short-circuit protection safety is particularly important. Due to the increase in charging and discharging capacity, large current is used for charging and discharging, so the internal resistance of the battery cell needs to be reduced proportionally, and at the same time, the voltage platform is increased. According to Ohm's law, when the high voltage and low resistance are used, the short-circuit current increases exponentially. Therefore, it is an important topic to study how to increase the short-circuit protection capability of the battery pack. It needs to have the characteristics of high efficiency, strong reliability, and full current protection to comprehensively guarantee the short-circuit protection safety of electric motorcycles.

[0034] The existing solution uses the hardware tolerance of the MOS tube on the battery management system protection board for protection. The main disadvantages of this solution are: first, the upper limit of the short-circuit protection current is small, usually within 1500A, and it cannot protect against currents above 1500A. That is to say, when the short-circuit current is greater than 1500A, the existing protection board cannot provide protection, and the MOS tube fails by breakdown, that is, the high-voltage circuit is the pathway, which causes the battery system to be insulated and subjected to the risk of electric shock, and the battery cannot be repaired and used; second, when the battery pack 11 itself is short-circuited, the existing protection board cannot provide protection; third, the existing protection board has a single protection method and a low functional safety level.

[0035] To solve the above problems, refer to Figure 1 According to a first aspect of an embodiment of the present application, a short circuit protection circuit of a battery pack is provided, comprising: At least one short circuit protection module among the first short circuit protection module 20, the second short circuit protection module, the third short circuit protection module 40 and the fourth short circuit protection module 50, wherein the first short circuit protection module 20, the second short circuit protection module, the third short circuit protection module 40 and the fourth short circuit protection module 50 are respectively used to be connected in series with the battery pack 11 to form a charge and discharge loop; Among them, the first short-circuit protection module 20 is used to cut off the charging and discharging circuit when a short circuit occurs in the battery pack 11 itself; at least one short-circuit protection module among the first short-circuit protection module 20, the second short-circuit protection module, the third short-circuit protection module 40 and the fourth short-circuit protection module 50 is used to cut off the charging and discharging circuit when a short circuit occurs in the battery pack as a whole, and the third short-circuit protection module 40 and / or the fourth short-circuit protection module 50 are also used to cut off the charging and discharging circuit when the electrical equipment corresponding to the battery pack or the battery pack management system fails.

[0036] Specifically, the battery pack 10 generally includes one or more battery groups 11 and related electrical components. The battery group 11 includes one or more battery modules, which can be formed by connecting different forms of battery modules 111 through connecting copper bars 12. The battery module 111 is formed by connecting multiple battery cells in series or in parallel. For example, Figure 2 As shown, the battery pack 10 includes a plurality of battery packs 11 of different forms connected, wherein two battery packs 11 have the same size, and the other two battery packs 11 have different sizes. Each battery pack 11 has a positive electrode and a negative electrode, and the battery modules 111 constituting each battery pack 11 also have a positive electrode and a negative electrode, and can be charged and discharged. At least one short-circuit protection module among the first short-circuit protection module 20, the second short-circuit protection module, the third short-circuit protection module 40 and the fourth short-circuit protection module 50 is connected in series with the positive electrode or the negative electrode of the battery pack 11 to form a charge and discharge loop.

[0037] In one example, the charge and discharge circuit refers to a positive high-voltage connector connected to the positive pole of the battery pack 11, and a negative high-voltage connector connected to the negative pole of the battery pack 11, thereby forming a charge and discharge circuit. The charge and discharge circuit is connected in series with a first short-circuit protection module, which can be used for automatic triggering protection when the battery pack 11 itself is short-circuited.

[0038] In another example, the charge and discharge loop refers to a positive high voltage connector connected to the positive electrode of the battery pack 11, the positive high voltage connector is connected to the load, the negative electrode of the battery pack 11 is connected to the negative high voltage connector, the negative high voltage connector is connected to the load, thereby forming a charge and discharge loop, in which the first short circuit protection module 20, the second short circuit protection module, the third short circuit protection module 40 and the fourth short circuit protection module 50 are connected in series. The load 90 refers to an electronic device or equipment connected to the output end of the battery pack 10, and the electronic device or equipment consumes the electrical energy provided by the battery pack 10.

[0039] A short circuit in the battery pack 11 itself usually refers to a short circuit caused by problems in the battery module 111 or the battery cell inside the battery pack 11, affecting a local area inside the battery pack 11. For example, damage to the diaphragm between the battery cells, electrolyte leakage, contact between the positive and negative electrodes, etc. can cause a short circuit in the battery module itself. In addition, overcharging, over-discharging, excessive temperature or improper use may also cause a short circuit in the battery pack 11 itself.

[0040] An overall short circuit of a battery pack refers to a short circuit caused by the failure of any device in the charge and discharge circuit formed by the battery pack 11, which affects the performance and safety of the entire battery pack 10. It is usually caused by a failure in the circuit design, connection or external system of the battery pack. For example, a power supply failure, line overload, short circuit or incorrect device connection may cause an overall short circuit of the battery pack.

[0041] The main causes of battery pack management system (BMS system) failures include hardware failure, software failure and external factors. Hardware failure is the most common type of failure in the BMS system, including sensor failure, controller failure, communication failure, etc. Sensor failure may cause the BMS to be unable to accurately obtain the battery status, controller failure may affect the battery charging and discharging process, and communication failure may cause the BMS to be unable to receive or send correct information. Software failures include program errors, improper parameter settings, data loss, etc. Among them, program errors may cause abnormal system operation, improper parameter settings may cause battery overcharging, over-discharging or overheating, and data loss will affect fault diagnosis and life prediction. External factors such as ambient temperature, humidity, electromagnetic interference, etc. may also affect the performance of the BMS system.

[0042] The failure of the electric equipment corresponding to the battery pack refers to a collision of the electric equipment, etc. For example, if the vehicle corresponding to the battery pack 10 collides, the displacement sensor on the vehicle is used to detect whether the vehicle has collided.

[0043] The short circuit protection circuit of the battery pack provided in the embodiment of the present application includes at least one short circuit protection module among a first short circuit protection module 20 , a second short circuit protection module, a third short circuit protection module 40 and a fourth short circuit protection module 50 .

[0044] Exemplarily, if only one short-circuit protection module is included, the first short-circuit protection module 20, the second short-circuit protection module, the third short-circuit protection module 40 and the fourth short-circuit protection module 50 are respectively connected in series with the battery pack 11 as independent short-circuit protection modules to form a charge and discharge circuit. The first short-circuit protection module 20, the second short-circuit protection module, the third short-circuit protection module 40 and the fourth short-circuit protection module 50 are respectively used as four basic battery pack short-circuit protection modes, which are combined together to constitute the short-circuit protection strategy of the battery pack of the present application. Among them, each short-circuit protection module can be connected in series with the positive or negative electrode of the battery pack 11. Being connected in series with the positive electrode of the battery pack 11 means that each short-circuit protection module is connected in series between the positive electrode of the battery pack 11 and the load 90. Being connected in series with the negative electrode of the battery pack 11 means that each short-circuit protection module is connected in series between the negative electrode of the battery pack 11 and the load 90. The principle of subsequent connection with the positive or negative electrode of the battery pack 11 is the same as this, and the embodiments of the present application will not be repeated.

[0045] Exemplarily, two short-circuit protection modules are included, and the two short-circuit protection modules are connected in series and are respectively connected in series with the battery pack 11 and the load 90 to form a charge and discharge loop, wherein the two short-circuit protection modules can be connected in series with the positive electrode of the battery pack 11, or both are connected in series with the negative electrode of the battery pack 11, or one is connected in series with the positive electrode of the battery pack 11, and the other is connected in series with the negative electrode of the battery pack 11. For example, the two short-circuit protection modules are: the first short-circuit protection module 20 and the second short-circuit protection module, the first short-circuit protection module 20 and the third short-circuit protection module 40, the first short-circuit protection module 20 and the fourth short-circuit protection module 50, the second short-circuit protection module and the third short-circuit protection module 40, the second short-circuit protection module and the fourth short-circuit protection module 50, and the third short-circuit protection module 40 and the fourth short-circuit protection module 50. In this example, the protection can be completed by triggering any one of the two short-circuit protection modules, thereby improving the efficiency, safety and reliability of the short-circuit protection of the battery pack 10.

[0046] Exemplarily, if three short-circuit protection modules are included, the three short-circuit protection modules are connected in series and are respectively connected in series with the battery pack 11 and the load 90 to form a charge and discharge loop. The three short-circuit protection modules can be connected in series with the positive electrode of the battery pack 11, or connected in series with the negative electrode of the battery pack 11, or partially connected in series with the positive electrode of the battery pack 11 and the remaining part connected in series with the negative electrode of the battery pack 11. For example, the three short-circuit protection modules are: the first short-circuit protection module 20, the second short-circuit protection module and the third short-circuit protection module 40, the first short-circuit protection module 20, the second short-circuit protection module and the fourth short-circuit protection module 50, the first short-circuit protection module 20, the third short-circuit protection module 40 and the fourth short-circuit protection module 50, the second short-circuit protection module, the third short-circuit protection module 40 and the fourth short-circuit protection module 50. In this example, the protection can be completed by triggering any one of the three short-circuit protection modules, thereby improving the efficiency, safety and reliability of the short-circuit protection of the battery pack 10.

[0047] Exemplarily, if four short-circuit protection modules are included, the four short-circuit protection modules are connected in series and are respectively connected in series with the battery pack 11 and the load 90 to form a charge and discharge loop. The four short-circuit protection modules can all be connected in series with the positive electrode of the battery pack 11, or all be connected in series with the negative electrode of the battery pack 11, or part of them are connected in series with the positive electrode of the battery pack 11, and the rest are connected in series with the negative electrode of the battery pack 11. The four short-circuit protection modules are respectively a first short-circuit protection module 20, a second short-circuit protection module, a third short-circuit protection module 40, and a fourth short-circuit protection module 50. In this example, the protection can be completed by triggering any one of the four short-circuit protection modules, thereby improving the efficiency, safety, and reliability of the short-circuit protection of the battery pack 10.

[0048] In the embodiment of the present application, the first short circuit protection module 20, the second short circuit protection module, the third short circuit protection module 40 and the fourth short circuit protection module 50 serve as independent short circuit protection modes or multiple combined short circuit protection modes, which improve the safety level of short circuit protection of the battery pack 10 and further improve the safety of the battery pack 10.

[0049] In some embodiments, reference Figures 2 to 4 The first short-circuit protection module 20 includes a first narrow-diameter metal member 21 and a second narrow-diameter metal member 22, and the first narrow-diameter metal member 21 and the second narrow-diameter metal member 22 are respectively electrically connected to the positive electrode and the negative electrode of the battery pack 11 and / or the battery module 111 constituting the battery pack 11; it should be understood that, if Figure 4As shown, the battery module 111 constituting the battery pack 11 may also have a positive electrode and a negative electrode, so that the first narrow-diameter metal member 21 and the second narrow-diameter metal member 22 are electrically connected to the positive electrode and the negative electrode of the battery module 111, respectively. That is, a plurality of first narrow-diameter metal members 21 and second narrow-diameter metal members 22 may be provided in the battery pack 11, so as to form a corresponding first short-circuit protection module 20 at the positive electrode and the negative electrode of each battery module 111, that is, the number of the first short-circuit protection modules 20 is less than or equal to the number of the battery modules 111 included in the battery pack 11; The first narrow-diameter metal member 21 and the second narrow-diameter metal member 22 both include a first metal segment 210 and a second metal segment 220 that are bent and connected. The width of the first metal segment 210 and the second metal segment 220 at the connection is smaller than the width of the first metal segment 210 and smaller than the width of the second metal segment 220. The purpose of this setting is to make the flow area of ​​the first metal segment 210 and the second metal segment 220 at the connection smaller than the width of the first metal segment 210 and smaller than the flow area of ​​the second metal segment 220.

[0050] Specifically, the first narrow diameter metal member 21 is electrically connected to the positive electrode of the battery pack 11, and the second narrow diameter metal member 22 is electrically connected to the negative electrode of the battery pack 11. The first narrow diameter metal member 21 and the second narrow diameter metal member 22 have the same structure. Exemplarily, the first narrow diameter metal member 21 and the second narrow diameter metal member 22 can be narrow diameter copper bars or narrow diameter aluminum bars, preferably narrow diameter copper bars. The narrow diameter copper bar includes a first metal segment 210 and a second metal segment 220 connected by bending. The first metal segment 210 and the second metal segment 220 can be integrally formed. The width of the first metal segment 210 and the second metal segment 220 at the connection is smaller than the width of the first metal segment 210, and smaller than the width of the second metal segment 220, so that the narrow diameter copper bar forms a narrow diameter at the connection between the first metal segment 210 and the second metal segment 220. When the current is overloaded, the narrow diameter of the narrow diameter copper bar will be deformed by high temperature and melted. At this time, the fuse is the position where the narrow diameter copper bar terminates the current. The first metal segment 210 serves as a current overcurrent zone, and the connection between the first metal segment 210 and the second metal segment 220 serves as a fuse zone, wherein a stud is further provided at one end of the second metal segment 220 away from the first metal segment 210, and the stud can pass through the connecting copper bar 12 on the battery pack 11 and be screwed with bolts, that is, the first narrow-diameter metal member 21 and the second narrow-diameter metal member 22 are both detachably connected to the connecting copper bar 12 through the stud and the bolt. The battery cell in the battery pack 11 has a positive pole tab and a negative pole tab, and the positive pole tab can pass through the tab welding hole 211 on the first narrow-diameter metal member 21 and be welded to the first narrow-diameter metal member 21, and the negative pole tab can pass through the tab welding hole 211 on the second narrow-diameter metal member 22 and be welded to the second narrow-diameter metal member 22, playing the role of a busbar.

[0051] In this example, by respectively providing narrow diameter copper busbars at the positive and negative electrodes of the battery pack 11, a protective effect can be provided when a short circuit occurs in the battery pack 11 itself. When the short circuit current of the battery pack 11 itself reaches 8000A, the narrow diameter copper busbar is automatically triggered to fuse to cut off the charge and discharge circuit, thereby completing the short circuit protection of the battery pack 11.

[0052] In some embodiments, reference Figure 4 The first metal segment 210 is provided with a tab welding hole 211 extending along the length direction, and a plurality of via holes 221 are provided along the width direction at the connection between the first metal segment 210 and the second metal segment 220 .

[0053] Specifically, the electrode ear welding hole 211 allows the first narrow diameter metal part 21 and the second narrow diameter metal part 22 to be used as a busbar, and the entire battery module 111 does not need to add additional connecting components. The narrow diameter copper busbar is provided with at least one via 221 along the width direction at the narrow diameter. For example, as 2, 3, etc., the via 221 can be provided with a cross-sectional area at the narrow diameter. When the current is overloaded, the narrow diameter of the narrow diameter copper busbar will be quickly melted due to high temperature deformation, thereby reducing the melting time, improving the melting efficiency of the narrow diameter copper busbar, and thus improving the short-circuit protection efficiency of the first short-circuit protection module 20. Among them, the melting simulation test results of the narrow diameter copper busbar are as follows: Figure 5 As shown in the figure, when the short-circuit current reaches 8000A, the narrow-diameter copper busbar can quickly fuse within 1s.

[0054] In some embodiments, reference Figure 1 , Figure 2 and Figure 6 The second short-circuit protection module includes a fuse 30 , and the fuse 30 is connected in series with the positive electrode or the negative electrode of the battery pack 11 .

[0055] Specifically, the fuse 30 is a thermal fuse, which is a passive high-current fuse protection device. When a short-circuit current occurs in the charge and discharge circuit formed by the battery pack 11, the fuse 30 heats up to the melting point faster than the heat release rate, and quickly blocks the current. When the fuse 30 burns out, the sand inside it will extinguish the arc, and then absorb energy to form lava, and then insulate the line from the load 90, eliminating the risk of electric shock. The fuse 30 is connected in series with the positive or negative electrode of the battery pack 11. Preferably, the fuse 30 is arranged at the positive electrode of the battery pack 11, that is, the fuse 30 is arranged between the positive electrode of the battery pack 11 and the load 90, which can protect the short-circuit protection of the battery pack 10 as a whole, and meet the short-circuit protection requirements of the full short-circuit current of the battery pack 10. When the short-circuit current ranges from 1500A to 10KA, the fuse 30 automatically melts to cut off the charge and discharge circuit and complete the short-circuit protection. Among them, the short-circuit current refers to the large current pulse discharge generated by the external short circuit of the battery pack 11.

[0056] In some embodiments, reference Figure 1 The third short circuit protection module 40 includes a first charge and discharge unit 41, which is connected in series with the positive electrode or the negative electrode of the battery pack 11, and the first charge and discharge unit 41 includes a discharge switch tube 410 and a charge switch tube 420 connected in series.

[0057] Specifically, the on and off of the charge and discharge circuit can be controlled by controlling the on and off of the first charge and discharge unit 41. When the battery pack is short-circuited as a whole, or when the power-consuming device or the battery pack management system fails and shorts, the first charge and discharge unit 41 is triggered to cut off the charge and discharge circuit to complete short circuit protection. The discharge switch tube 410 and the charge switch tube 420 can be connected in series to the positive or negative electrode of the battery pack 11. The discharge switch tube 410 and the charge switch tube 420 can control the flow direction of the current in the charge and discharge circuit and the on and off of the charge and discharge circuit.

[0058] It should be noted that the controller 70 can independently control the conduction and disconnection of the discharge switch tube 410 and the charging switch tube 420, wherein the discharge switch tube 410 and the charging switch tube 420 are both disconnected to cut off the charge and discharge circuit, and the conduction of any switch tube can realize the conduction of the charge and discharge circuit. In the charging process, the charging switch tube 420 is in the conducting state, the discharge switch tube 410 is in the non-conducting state, and the charging current can still flow through the first body diode 4102 inside the discharge switch tube 410, thereby realizing the conduction of the charging circuit; in the discharging process, the discharge switch tube 410 is in the conducting state, the charging switch tube 420 is in the non-conducting state, and the discharge current can still flow through the second body diode 4202 inside the charging switch tube 420, thereby realizing the conduction of the discharge circuit.

[0059] In some embodiments, reference Figures 7 to 9 , the discharging switch tube 410 is a first N-type MOS tube 4101, the charging switch tube 420 is a second N-type MOS tube 4201, the source of the first N-type MOS tube 4101 is connected to the positive electrode of the battery pack 11, the drain of the first N-type MOS tube 4101 is connected to the drain of the second N-type MOS tube 4201, and a first body diode 4102 is connected between the source and the drain of the first N-type MOS tube 4101; The source of the second N-type MOS transistor 4201 is connected to the load 90 , the gate of the second N-type MOS transistor 4201 and the gate of the first N-type MOS transistor 4101 are both connected to the controller 70 , and a second body diode 4202 is connected between the source and drain of the second N-type MOS transistor 4201 .

[0060] Specifically, the first N-type MOS transistor 4101 and the second N-type MOS transistor 4201 can be arranged on the protection board 100, and the two can be connected in series to the positive or negative electrode of the battery pack 11 for active or passive protection of the battery pack 11 against a small short-circuit current (500A~1500A) and active protection when the electrical equipment or the battery pack management system fails. The positive terminal of the first body diode 4102 is connected to the source of the first N-type MOS transistor 4101, and the negative terminal of the first body diode 4102 is connected to the drain of the first N-type MOS transistor 4101; the positive terminal of the second body diode 4202 is connected to the source of the second N-type MOS transistor 4201, and the negative terminal of the second body diode 4202 is connected to the drain of the second N-type MOS transistor 4201.

[0061] During the charging process, the second N-type MOS tube 4201 is turned on and the first N-type MOS tube 4101 is turned off, and the charging current can flow through the first body diode 4102 and flow from the positive terminal to the negative terminal of the first body diode 4102, thereby realizing the conduction of the charging circuit; during the discharging process, the first N-type MOS tube 4101 is turned on and the second N-type MOS tube 4201 is turned off, and the discharging current can flow through the second body diode 4202 and flow from the positive terminal to the negative terminal of the second body diode 4202, thereby realizing the conduction of the discharging circuit.

[0062] In this example, the controller 70 controls the conduction and shutdown of the first N-type MOS tube 4101 and the second N-type MOS tube 4201 by controlling the gate signals of the first N-type MOS tube 4101 and the second N-type MOS tube 4201. The gates of the first N-type MOS tube 4101 and the second N-type MOS tube 4201 are connected to the controller 70 through the AFE chip 612. The charge and discharge circuit can only be cut off when the first N-type MOS tube 4101 and the second N-type MOS tube 4201 are both disconnected. The conduction of any one of the first N-type MOS tube 4101 and the second N-type MOS tube 4201 can realize the conduction of the charge and discharge circuit, so as to realize the charging and discharging operation of the battery pack 11.

[0063] On the one hand, the first charge and discharge unit 41 is used for active switching protection of small short-circuit current when the entire battery pack is short-circuited. When the protection board 100 detects a current of 500A~1500A through the current detection unit, the protection board 100 controls the first N-type MOS tube 4101 and the second N-type MOS tube 4201 to fuse through software to complete short-circuit protection. On the other hand, when the electrical equipment or the battery pack management system fails and short-circuit occurs, when the protection board 100 detects a thermal runaway or collision signal, the protection board 100 controls the first N-type MOS tube 4101 and the second N-type MOS tube 4201 to fuse through software to complete short-circuit protection.

[0064] In some embodiments, reference Figure 7 and Figure 8 The third short-circuit protection module 40 also includes a second charge and discharge unit 42, which is connected in parallel with the first charge and discharge unit 41. The second charge and discharge unit 42 includes a first resistor 421 and a P-type MOS tube 422 connected in series, wherein a third body diode 423 is connected between the source and the drain of the P-type MOS tube 422.

[0065] Specifically, the positive electrode of the battery pack 11 is connected in series with the second charge and discharge unit 42, that is, the positive electrode of the battery pack 11 is connected in sequence with the first resistor 421 and the P-type MOS tube 422, and the second charge and discharge unit 42 is connected in parallel with the first charge and discharge unit 41, and the second charge and discharge unit 42 can be controlled to be turned on and off by the P-type MOS tube 422. When the second charge and discharge unit 42 is turned on, the first charge and discharge unit 41 is in a cut-off state, and the pre-charge and pre-discharge operations of the battery pack 11 can be realized, avoiding damage to the first N-type MOS tube 4101 and the second N-type MOS tube 4201 and other devices caused by excessive instantaneous current. Among them, the resistance value of the first resistor 421 can be set according to actual needs, and the embodiment of the present application is not particularly limited.

[0066] It can be understood that if the third short circuit protection module 40 includes a first charge and discharge unit 41 and a second charge and discharge unit 42, the first charge and discharge unit 41 and the second charge and discharge unit 42 must be disconnected to achieve the cutting off of the charge and discharge circuit; if the first charge and discharge unit 41 is turned on and the second charge and discharge unit 42 is disconnected, the battery pack 11 performs a formal charge and discharge operation; if the first charge and discharge unit 41 is disconnected and the second charge and discharge unit 42 is turned on, the battery pack 11 performs a pre-charge and discharge operation.

[0067] In some embodiments, reference Figure 7 and Figure 8 The second charge and discharge unit 42 further includes an anti-reverse diode 424, a positive terminal of the anti-reverse diode 424 is connected to the P-type MOS tube 422, and a negative terminal of the anti-reverse diode 424 is connected to the load 90.

[0068] Specifically, the anti-reverse diode 424 is connected between the P-type MOS tube 422 and the load 90, and can control the flow direction of the current to prevent the current from reversing.

[0069] In some embodiments, reference Figure 1 and Figure 7 The fourth short circuit protection module 50 includes a first fuse 51 and / or a second fuse 52, wherein the first fuse 51 and the second fuse 52 are connected in parallel to form a first parallel circuit, and the first parallel circuit is connected in series with the positive electrode or the negative electrode of the battery pack 11.

[0070] Specifically, the first fuse 51 and the second fuse 52 can be connected in series to the positive electrode or the negative electrode of the battery pack 11, preferably in series to the positive electrode. The fourth short-circuit protection module 50 includes the first fuse 51 or the second fuse 52, and the charge-discharge circuit can be cut off when the first fuse 51 or the second fuse 52 is blown; the fourth short-circuit protection module 50 includes the first fuse 51 and the second fuse 52, and the charge-discharge circuit can be cut off only when both the first fuse 51 and the second fuse 52 are blown.

[0071] In this example, the fourth short-circuit protection module 50 is used on the one hand to complete short-circuit protection when the entire battery pack is short-circuited and the short-circuit current range is 500A~10KA, and the first fuse 51 and the second fuse 52 are blown; on the other hand, when the electrical equipment or the battery pack management system fails and short-circuits, when the protection board 100 detects a thermal runaway or collision signal, the software controls the first fuse 51 and the second fuse 52 to blow, completing short-circuit protection.

[0072] In some embodiments, reference Figure 7 The first fuse 51 is a two-terminal fuse, and the second fuse 52 is a three-terminal fuse.

[0073] Specifically, refer to Fig.10 and Fig.11 The two-terminal fuse and the three-terminal fuse are both arranged on the protection board 100, and are arranged on two sides opposite to the first charge and discharge unit 41 of the protection board 100. Among them, the two-terminal fuse is a current protection device with passive switching control, which means that when the short-circuit current exceeds the limit value, the two-terminal fuse will automatically melt and cut off the charge and discharge circuit to play a protective role; the three-terminal fuse is a battery protection device with active or passive switching control, which can forcibly control the cutting off of the charge and discharge circuit to play a protective role.

[0074] In some embodiments, reference Figure 1 and Figure 7 The short-circuit protection circuit also includes a current detection module 60 and a controller 70. The current detection module 60 is used to detect the current information of the charging and discharging circuit. The signal output end of the current detection module 60 is electrically connected to the signal input end of the controller 70. The signal output end of the controller 70 is electrically connected to the third short-circuit protection module 40 and the fourth short-circuit protection module 50 respectively.

[0075] Specifically, the current detection module 60 is used to detect the current information of the charge and discharge circuit, determine whether the charge and discharge circuit is short-circuited according to the detected current information, and send the short-circuit information to the controller 70 when it is determined that the charge and discharge circuit is short-circuited. The controller 70 may be a microcontroller unit (MCU), which controls the third short-circuit protection module 40 or / and the fourth short-circuit protection module 50 to cut off the charge and discharge circuit in response to the short-circuit information. Among them, the third short-circuit protection module 40 cuts off the charge and discharge circuit, which means that the first charge and discharge unit 41 and the second charge and discharge unit 42 are both disconnected, that is, the first N-type MOS tube 4101 and the second N-type MOS tube 4201 are both disconnected, and the P-type MOS tube 422 is disconnected. The fourth short-circuit protection module 50 cuts off the charge and discharge circuit, which means that the first fuse 51 and the second fuse 52 are both disconnected.

[0076] In some embodiments, reference Figure 1 and Figure 7 , the current detection module 60 includes a first current acquisition unit 61 and / or a second current acquisition unit 62, wherein the first current acquisition unit 61 and the second current acquisition unit 62 are connected in series; The first current acquisition unit 61 includes a first sampling resistor 611 and an AFE chip 612 connected in parallel; the second current acquisition unit 62 includes a second sampling resistor 621 and an OPA chip 622 connected in parallel.

[0077] Specifically, the current detection module 60 can be integrated on the protection board 100, and the first current acquisition unit 61 and the second current acquisition unit 62 can both obtain the current information of the charge and discharge circuit. According to the obtained current information, the fault type of the battery pack 10 can be determined, and then the short circuit protection mode of the battery pack 10 can be determined. Among them, the AFE (Active Front End) chip has the function of a rectifier / feedback unit, which obtains the current information of the charge and discharge circuit through the first sampling resistor 611, and the obtained current information is sent to the controller 70; the OPA (Operational Amplifier) ​​chip is an integrated circuit, which is mainly used for current amplification and signal processing, and obtains the current information of the charge and discharge circuit through the second sampling resistor 621, and the obtained current information is sent to the controller 70. Among them, the resistance values ​​of the first sampling resistor 611 and the second sampling resistor 621 can be set according to actual needs, and this application does not make special restrictions. Among them, in addition to the integrated current detection module 60, the third short-circuit protection module 40 and the fourth short-circuit protection module 50, the controller 70, the AFE chip 612, and the OPA chip 622, the protection board 100 can also integrate other conventional devices, such as a heating control module 110, etc. The heating control module 110 is used to heat the battery pack 11. The heating control module 110 includes a two-terminal fuse and a P-type MOS tube connected in series, which will not be elaborated in this application.

[0078] The short-circuit protection circuit of the battery pack provided in the embodiment of the present application can achieve full current protection, and can protect from the minimum fault current to the maximum short-circuit current (500A~10KA). It has the characteristics of good stability, strong reliability, comprehensiveness, and a wide range of protection current. It can be used for short-circuit protection of electrical equipment such as electric motorcycles.

[0079] The second aspect of the present invention, referring to Fig.12 , a short circuit protection method for a battery pack is provided, comprising: Preset the fault type of the battery pack 10, where the fault type of the battery pack 10 includes a short circuit of the battery group 11 itself, a short circuit of the entire battery pack, and a fault of the power-consuming device corresponding to the battery pack or the battery pack management system; According to the fault type of the battery pack 10, at least one of the first short circuit protection module 20, the second short circuit protection module, the third short circuit protection module 40 and the fourth short circuit protection module 50 is triggered to cut off the charge and discharge circuit; wherein, When the battery pack 11 itself is short-circuited, the first short-circuit protection module 20 is triggered to cut off the charging and discharging circuit; When the battery pack as a whole is short-circuited, at least one of the first short-circuit protection module 20, the second short-circuit protection module, the third short-circuit protection module 40 and the fourth short-circuit protection module 50 is triggered to cut off the charge and discharge circuit; When the power-consuming device corresponding to the battery pack or the battery pack management system fails, the third short-circuit protection module 40 and / or the fourth short-circuit protection module 50 are triggered to cut off the charge and discharge loop.

[0080] Specifically, the short-circuit modes of the battery pack 10 are mainly divided into three categories: the first category is a short circuit of the battery pack 11 itself, the second category is a short circuit of the charge and discharge circuit formed by the battery pack 11, and the third category is a short circuit caused by a fault in the power-consuming device or the battery pack management system corresponding to the battery pack 11. The fault type of the battery pack 11 is preset to determine the use of different short-circuit protection modes. One or more combinations can be used to implement short-circuit protection, thereby increasing the comprehensiveness and reliability of the short-circuit protection of the battery pack 10.

[0081] In some embodiments, reference Fig.12 , the short circuit protection method of the battery pack includes: If it is detected that the short-circuit current of the battery pack 11 itself reaches a first current threshold range, it is determined that the fault type of the battery pack 11 is a short circuit of the battery pack 11 itself. For example, the first current threshold range may be 8000A~10KA; If it is detected that the short-circuit current of the charge-discharge loop reaches the second current threshold range or the third current threshold range, it is determined that the fault type of the battery pack 10 is that the charge-discharge loop formed by the battery pack 11 is short-circuited; wherein the second current threshold range is greater than the third current threshold range; for example, the second current threshold range may be 1500A~10KA, and the third current threshold range may be 500A~1500A; If it is detected that the battery pack is thermally out of control or the electrical equipment corresponding to the battery pack is colliding, it is determined that the fault type of the battery pack is a fault of the electrical equipment corresponding to the battery pack or a battery pack management system.

[0082] Exemplarily, when a first type of short circuit occurs, that is, when a short circuit current greater than 8000A is detected, the first short circuit protection module 20 is triggered to cut off the charge and discharge circuit, completing the short circuit protection of the battery pack. When a second type of short circuit occurs, that is, when a short circuit current of 1500A~10KA is detected, at least one of the first short circuit protection module 20, the second short circuit protection module, and the fourth short circuit protection module 50 is triggered to cut off the charge and discharge circuit; when a short circuit current of 500A~1500A is detected, the third short circuit protection module 40 and / or the fourth short circuit protection module 50 are triggered to cut off the charge and discharge circuit. When a third type of short circuit occurs, that is, thermal runaway of the battery pack 10 is detected, the third short circuit protection module 40 and / or the fourth short circuit protection module 50 are triggered to cut off the charge and discharge circuit; or when a collision of the entire vehicle is detected, the third short circuit protection module 40 and / or the fourth short circuit protection module 50 are triggered to cut off the charge and discharge circuit.

[0083] Among them, the thermal runaway information of the battery pack 10 can be obtained through the voltage information and temperature information collected by the AFE, and the controller 70 can process and calculate whether the battery pack 10 has thermal runaway, wherein the thermal runaway trigger judgment conditions are: a) the trigger object produces a voltage drop, and the drop value exceeds 25% of the initial voltage; b) the temperature of the monitoring point reaches the maximum operating temperature specified by the manufacturer; c) the temperature rise rate dT / dt of the monitoring point ≥ 1°C / s, and lasts for more than 3s, wherein dT is the temperature change, and dt is the time change. The vehicle collision information corresponding to the battery pack 10 can be detected by displacement sensors installed on the vehicle, etc. This part is a prior art and will not be described in detail in the embodiments of this application. In some embodiments, reference Fig.12 If it is detected that the short-circuit current of the battery pack 11 itself reaches a first current threshold range, the first narrow-diameter metal member 21 and / or the second narrow-diameter metal member 22 are fused at the connection to cut off the charge and discharge circuit; If it is detected that the short-circuit current of the charge-discharge loop reaches the second current threshold range, at least one of the following operations is triggered: the first narrow-diameter metal part 21 is blown at the connection, the second narrow-diameter metal part 22 is blown at the connection, the fuse 30 is blown, the two-terminal fuse is blown, and the three-terminal fuse is blown; If it is detected that the short-circuit current of the charge-discharge loop reaches a third current threshold range, at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge-discharge unit 41 is disconnected, and the second charge-discharge unit 42 is disconnected; If the battery pack 10 is detected to be thermally out of control, at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge and discharge unit 41 is disconnected, and the second charge and discharge unit 42 is disconnected; If a collision is detected with the electrical equipment corresponding to the battery pack 10 , at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge and discharge unit 41 is disconnected, and the second charge and discharge unit 42 is disconnected.

[0084] Specifically, if it is detected that the short-circuit current of the battery pack 11 itself is greater than 8000A, the first short-circuit protection module 20 is triggered, and the first narrow-diameter metal part 21 and / or the second narrow-diameter metal part 22 are melted at the connection to cut off the charge and discharge circuit. If it is detected that the short-circuit current of the charge and discharge circuit reaches the second current threshold range of 1500A~10KA, one or more short-circuit protection modules among the first short-circuit protection module 20, the second short-circuit protection module and the fourth short-circuit protection module 50 are triggered to cut off the charge and discharge circuit. If it is detected that the battery pack 10 is thermally out of control or the electrical equipment collides, the third short-circuit protection module 40 and / or the fourth short-circuit protection module 50 are triggered to cut off the charge and discharge circuit.

[0085] The short-circuit protection method of the battery pack provided in the embodiment of the present application has passed the battery pack 5mΩ short-circuit test certification. The test method and judgment criteria comply with the "Safety Requirements for Power Batteries for Electric Vehicles" GB 38031-2020 standard, that is, the battery system is subjected to an external short-circuit protection test in accordance with 8.2.1.3. There should be no leakage, shell rupture, fire or explosion, and the insulation resistance after the test should be no less than 100Ω / V.

[0086] The short-circuit protection method of the battery pack provided in the embodiment of the present application has passed the battery pack 20mΩ short-circuit test certification. The test method and judgment criteria comply with the 5.2.1.4 section of the "Safety Technical Specifications for Lithium-ion Batteries for Electric Bicycles" GB 43854-2024 standard, that is, the battery pack should not leak, rupture, catch fire, or explode when tested according to the test method of 6.4.1.4.

[0087] The short-circuit protection method of the battery pack provided in the embodiment of the present application has also passed the experimental certification of secondary protection, that is, when the battery pack is short-circuited due to overcurrent, two short-circuit protection modes are triggered to cut off the charging and discharging circuits, thereby completing short-circuit protection.

[0088] According to a third aspect of the present invention, a battery pack 10 is provided, comprising the short-circuit protection circuit of the battery pack described in any embodiment of the present application.

[0089] Specifically, the specific technical features and technical effects of the battery pack 10 are consistent with the technical features and technical effects of the short-circuit protection circuit of the battery pack, and will not be repeated in the embodiments of the present application.

[0090] A fourth aspect of the present invention provides a battery pack management system, comprising: the battery pack 10 and the load 90 as described in any embodiment of the present application, wherein the short-circuit protection circuit is respectively connected in series with the load 90 to form a charge and discharge loop.

[0091] Specifically, the specific technical features and technical effects of the battery pack management system are consistent with the technical features and technical effects of the short-circuit protection circuit of the battery pack, and will not be repeated in the embodiments of the present application.

[0092] The short circuit protection circuit of the present application can be used for different types of battery packs 10, such as platform battery packs, standard battery packs, other customized battery packs, etc. For example, the structure of a typical battery pack is as follows: Figure 2 shown.

[0093] According to a fifth aspect of the present invention, there is provided an electrical device, which includes the short-circuit protection circuit of the battery pack described in any embodiment of the present application, or includes the battery pack described in any embodiment of the present application, or includes the battery pack management system of any embodiment of the present application.

[0094] Specifically, the specific technical features and technical effects of the electrical equipment are consistent with the technical features and technical effects of the short-circuit protection circuit of the battery pack, and will not be repeated in the embodiments of the present application.

[0095] It should be noted that electrical equipment can be vehicles such as electric motorcycles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.; spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc. The embodiments of the present invention do not impose special restrictions on the above-mentioned electrical equipment.

[0096] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other to form a technical solution.

Claims

1. A short circuit protection circuit for a battery pack, characterized in that: include: At least one short circuit protection module among the first short circuit protection module (20), the second short circuit protection module, the third short circuit protection module (40) and the fourth short circuit protection module (50), wherein the first short circuit protection module (20), the second short circuit protection module, the third short circuit protection module (40) and the fourth short circuit protection module (50) are respectively used to be connected in series with the battery pack (11) to form a charge and discharge loop; The first short circuit protection module (20) is used to cut off the charge and discharge circuit when a short circuit occurs in the battery pack (11) itself; at least one of the first short circuit protection module (20), the second short circuit protection module, the third short circuit protection module (40) and the fourth short circuit protection module (50) is used to cut off the charge and discharge circuit when a short circuit occurs in the entire battery pack; the third short circuit protection module (40) and / or the fourth short circuit protection module (50) are also used to cut off the charge and discharge circuit when an electric device corresponding to the battery pack or a battery pack management system fails.

2. The short circuit protection circuit of the battery pack according to claim 1, characterized in that: The first short circuit protection module (20) comprises a first narrow diameter metal member (21) and a second narrow diameter metal member (22), the first narrow diameter metal member (21) and the second narrow diameter metal member (22) being electrically connected to the positive electrode and the negative electrode of the battery pack (11) and / or the battery module (111) constituting the battery pack (11), respectively; The first narrow-diameter metal member (21) and the second narrow-diameter metal member (22) both comprise a first metal segment (210) and a second metal segment (220) which are connected, and a flow area at a connection point between the first metal segment (210) and the second metal segment (220) is smaller than a flow area of ​​the first metal segment (210) and smaller than a flow area of ​​the second metal segment (220).

3. The short circuit protection circuit of the battery pack according to claim 2, characterized in that: The width of the first metal segment (210) and the second metal segment (220) at the connection point is smaller than the width of the first metal segment (210), and smaller than the width of the second metal segment (220).

4. The short circuit protection circuit of the battery pack according to claim 3, characterized in that: The first metal segment (210) is provided with a tab welding hole (211) extending in the length direction, and a plurality of via holes (221) are provided in the width direction at the connection between the first metal segment (210) and the second metal segment (220).

5. The short circuit protection circuit of the battery pack according to claim 1, characterized in that: The second short-circuit protection module comprises a fuse (30), and the fuse (30) is connected in series with the positive electrode or the negative electrode of the battery pack (11).

6. The short circuit protection circuit of the battery pack according to claim 1, characterized in that: The third short circuit protection module (40) comprises a first charge and discharge unit (41), the first charge and discharge unit (41) being connected in series with a positive electrode or a negative electrode of the battery pack (11), the first charge and discharge unit (41) comprising a discharge switch tube (410) and a charge switch tube (420) connected in series.

7. The short circuit protection circuit of the battery pack according to claim 6, characterized in that: The discharge switch tube (410) is a first N-type MOS tube (4101), and the charge switch tube (420) is a second N-type MOS tube (4201); the source of the first N-type MOS tube (4101) is connected to the positive electrode of the battery pack (11), the drain of the first N-type MOS tube (4101) is connected to the drain of the second N-type MOS tube (4201), and a first body diode (4102) is connected between the source and drain of the first N-type MOS tube (4101); The source of the second N-type MOS transistor (4201) is connected to a load (90), the gate of the second N-type MOS transistor (4201) and the gate of the first N-type MOS transistor (4101) are both connected to a controller (70), and a second body diode (4202) is connected between the source and drain of the second N-type MOS transistor (4201).

8. The short circuit protection circuit of the battery pack according to claim 6 or 7, characterized in that: The third short-circuit protection module (40) further comprises a second charge-discharge unit (42), the second charge-discharge unit (42) being connected in parallel with the first charge-discharge unit (41), the second charge-discharge unit (42) comprising a first resistor (421) and a P-type MOS tube (422) connected in series, wherein a third body diode (423) is connected between the source and the drain of the P-type MOS tube (422).

9. The short circuit protection circuit of the battery pack according to claim 8, characterized in that: The second charge and discharge unit (42) further comprises a reverse protection diode (424), wherein a positive terminal of the reverse protection diode (424) is connected to the P-type MOS tube (422), and a negative terminal of the reverse protection diode (424) is connected to the load (90).

10. The short circuit protection circuit of the battery pack according to claim 1, characterized in that: The fourth short circuit protection module (50) comprises a first fuse (51) and / or a second fuse (52), wherein the first fuse (51) and the second fuse (52) are connected in parallel to form a first parallel circuit, and the first parallel circuit is connected in series with the positive electrode or the negative electrode of the battery pack (11).

11. The short circuit protection circuit of the battery pack according to claim 10, characterized in that: The first fuse (51) is a two-terminal fuse, and the second fuse (52) is a three-terminal fuse.

12. The short circuit protection circuit of the battery pack according to claim 1, characterized in that: The short-circuit protection circuit further comprises a current detection module (60) and a controller (70); the current detection module (60) is used to detect current information of the charge-discharge circuit; a signal output end of the current detection module (60) is electrically connected to a signal input end of the controller (70); and the signal output end of the controller (70) is electrically connected to the third short-circuit protection module (40) and the fourth short-circuit protection module (50), respectively.

13. The short circuit protection circuit of the battery pack according to claim 12, characterized in that: The current detection module (60) comprises a first current acquisition unit (61) and / or a second current acquisition unit (62), wherein the first current acquisition unit (61) and the second current acquisition unit (62) are connected in series; The first current acquisition unit (61) comprises a first sampling resistor (611) and an AFE chip (612) connected in parallel; the second current acquisition unit (62) comprises a second sampling resistor (621) and an OPA chip (622) connected in parallel.

14. A short circuit protection method for a battery pack, characterized in that: include: Preset a fault type of the battery pack (10), the fault type of the battery pack (10) comprising a short circuit of the battery group (11) itself, a short circuit of the battery pack (10) as a whole, and a fault of an electric device corresponding to the battery pack (10) or a battery pack management system; According to the fault type of the battery pack (10), at least one short circuit protection module among the first short circuit protection module (20), the second short circuit protection module, the third short circuit protection module (40) and the fourth short circuit protection module (50) is triggered to cut off the charge and discharge circuit; wherein, When the battery pack (11) itself is short-circuited, the first short-circuit protection module (20) is triggered to cut off the charging and discharging circuit; When the battery pack (10) as a whole is short-circuited, at least one of the first short-circuit protection module (20), the second short-circuit protection module, the third short-circuit protection module (40) and the fourth short-circuit protection module (50) is triggered to cut off the charge and discharge circuit; When an electric device or a battery pack management system corresponding to the battery pack (10) fails, the third short circuit protection module (40) and / or the fourth short circuit protection module (50) are triggered to cut off the charge and discharge circuit.

15. The short circuit protection method of the battery pack according to claim 14, characterized in that: If it is detected that the short-circuit current of the battery pack (11) itself reaches a first current threshold range, the first short-circuit protection module (20) is triggered to cut off the charging and discharging circuit; If it is detected that the short-circuit current of the charge-discharge loop formed by the battery pack reaches a second current threshold range or a third current threshold range, at least one of the first short-circuit protection module (20), the second short-circuit protection module, the third short-circuit protection module (40) and the fourth short-circuit protection module (50) is triggered to cut off the charge-discharge loop; If it is detected that the battery pack (10) is thermally out of control or a power-consuming device corresponding to the battery pack (10) collides, the third short-circuit protection module (40) and / or the fourth short-circuit protection module (50) are triggered to cut off the charge-discharge circuit.

16. The short circuit protection method of the battery pack according to claim 15, characterized in that: The first current threshold range is 8000A~10KA, the second current threshold range is 1500A~10KA, and the third current threshold range is 500A~1500A.

17. The short circuit protection method of a battery pack according to claim 15 or 16, characterized in that: If it is detected that the short-circuit current of the battery pack (11) itself reaches a first current threshold range, the first narrow-diameter metal piece (21) and / or the second narrow-diameter metal piece (22) are fused at the connection point to cut off the charge and discharge circuit; If it is detected that the short-circuit current of the charge-discharge loop reaches a second current threshold range, at least one of the following operations is triggered: the first narrow-diameter metal piece (21) is blown at the connection, the second narrow-diameter metal piece (22) is blown at the connection, the fuse (30) is blown, the two-terminal fuse is blown, and the three-terminal fuse is blown; If it is detected that the short-circuit current of the charge-discharge loop reaches a third current threshold range, at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge-discharge unit (41) is disconnected, and the second charge-discharge unit (42) is disconnected; If it is detected that the battery pack (10) is thermally out of control, at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge and discharge unit (41) is disconnected, and the second charge and discharge unit (42) is disconnected; If a collision is detected with the electrical equipment corresponding to the battery pack (10), at least one of the following operations is triggered: the two-terminal fuse is blown, the three-terminal fuse is blown, the first charge and discharge unit (41) is disconnected, and the second charge and discharge unit (42) is disconnected.

18. A battery pack (10), characterized in that: A short circuit protection circuit for a battery pack comprising any one of claims 1-13.

19. A battery pack management system, characterized in that: It comprises the battery pack (10) according to claim 18 and a load (90), wherein the short-circuit protection circuit and the load (90) are connected in series to form a charge-discharge loop.

20. An electrical equipment, characterized in that: A short circuit protection circuit for a battery pack comprising any one of claims 1 to 13, or a battery pack (10) comprising claim 18, or a battery pack management system comprising claim 19.

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