Flexible circuit boards and energy storage devices

Abstract

This application relates to a flexible circuit board and an energy storage device. The flexible circuit board includes a fuse, a normally closed reed switch, a magnetic core coil, and a buffer delay circuit. The first end of the fuse is connected to a cell monitoring unit, and the second end of the fuse is connected to the first end of the normally closed reed switch. The second end of the normally closed reed switch is connected to the first end of the buffer delay circuit. The second end of the buffer delay circuit is connected to the first end of the magnetic core coil. The second end of the magnetic core coil is connected to the battery module, and the distance between the magnetic core coil and the normally closed reed switch is within a preset distance range. The magnetic core coil generates a magnetic field based on a continuous or pulsed surge current flowing through it. The normally closed reed switch is driven by the magnetic field to disconnect the connection between the cell monitoring unit and the battery module. The buffer delay circuit delays the connection between the battery module and the normally closed reed switch. This application provides protection against continuous or pulsed surges.

Description

Technical Field

[0001] This application relates to the field of overcurrent protection technology, specifically to a flexible circuit board and an energy storage device. Background Technology

[0002] With the development of new energy technologies, batteries are being used in an increasingly wide range of fields. For example, they are used in battery-powered new energy vehicles, intelligent robots, and drones, and batteries can also be used to form energy storage systems.

[0003] A battery pack typically includes a battery module, a CSC (Cell Supervisory Circuit), and an FPC (Flexible Printed Circuit). Both the CSC and FPC are equipped with fuses. In the event of an abnormally large current in the circuit, the fuse on the CSC will blow before the fuse on the FPC, thus protecting the fuse on the FPC.

[0004] However, the above solutions do not provide protection against continuous or pulsed surges. Utility Model Content

[0005] To address the aforementioned issues, this application provides a flexible circuit board and an energy storage device that offer protection against continuous or pulsed surges.

[0006] In a first aspect, this application provides a flexible circuit board, which includes a fuse, a normally closed reed switch, a magnetic core coil, and a buffer delay circuit. The first end of the fuse is connected to a battery monitoring unit outside the flexible circuit board, and the second end of the fuse is connected to the first end of the normally closed reed switch. The second end of the normally closed reed switch is connected to the first end of the buffer delay circuit. The second end of the buffer delay circuit is connected to the first end of the magnetic core coil. The second end of the magnetic core coil is connected to a battery module, and the distance between the magnetic core coil and the normally closed reed switch is within a preset distance range. The magnetic core coil generates a magnetic field based on a continuous or pulsed surge current flowing through it. The normally closed reed switch is driven by the magnetic field to disconnect the connection between the battery monitoring unit and the battery module. The buffer delay circuit delays the connection between the battery module and the normally closed reed switch.

[0007] In the technical solution of this application embodiment, if a continuous or pulse-type surge occurs in the circuit, the magnetic core coil generates a magnetic field, causing the normally closed reed switch to open, thus providing overcurrent protection for the flexible circuit board. When the current in the circuit returns to normal, the magnetic field generated by the magnetic core coil is insufficient to open the normally closed reed switch, allowing it to reconnect the battery module and the cell monitoring unit, enabling the cell monitoring unit to monitor the battery module normally. In this case, the fuse on the cell monitoring unit does not need to blow, and the cell monitoring unit does not need to be replaced. Furthermore, the normally closed reed switch connecting the battery module and the cell monitoring unit allows the buffer delay circuit to buffer current, protecting the cell monitoring unit and reducing overcurrent damage.

[0008] In some embodiments, the flexible circuit board further includes a first circuit board, a second circuit board, and a third circuit board. The magnetic core coil includes a first wire disposed in the first circuit board, a second wire disposed in the second circuit board, and a magnetic core. The first and second circuit boards are stacked, with the first and second wires symmetrically arranged to form a coil. A first end of the coil is connected to a second end of a buffer delay circuit, and a second end of the coil is connected to a battery module. The magnetic core is disposed between the first and second circuit boards and is located at the center of the coil. The third circuit board is disposed adjacent to the side of the first and second circuit boards, and a normally closed reed switch is disposed inside the third circuit board. The distance between the magnetic core and the normally closed reed switch is within a preset distance range. In the technical solution of this application embodiment, embedding the normally closed reed switch and the magnetic core coil into the flexible circuit board reduces the overall volume occupied by the flexible circuit board.

[0009] In some embodiments, the flexible circuit board further includes a first protective shell and a second protective shell; the first protective shell covers a first surface of the first circuit board away from the second circuit board, and covers a second surface of the third circuit board flush with the first surface; the second protective shell covers a third surface of the second circuit board away from the first circuit board, and covers a fourth surface of the third circuit board flush with the third surface. In the technical solution of this application embodiment, the first and second protective shells cover the upper and lower surfaces of the normally closed reed switch and magnetic core coil of the flexible circuit board, which can reduce the interference of the magnetic field generated by the electromagnetic coil on other devices on the flexible circuit board, thereby improving the reliability of the flexible circuit board.

[0010] In some embodiments, the first and second protective shells are made of copper. In the technical solutions of this application, the first and second protective shells are made of copper, which provides good shielding against high-frequency electromagnetic waves, is easy to process, and has a moderate cost.

[0011] In some embodiments, the number of turns of the coil is proportional to the ampere-turns of the normally closed reed switch and the magnitude of the surge current. In the technical solution of this application embodiment, the number of turns of the coil is set according to the selection of the normally closed reed switch and the magnitude of the current to be protected, so that the magnetic core coil and the normally closed reed switch can be well matched, and the coil can be protected against continuous or pulse surges.

[0012] In some embodiments, the distance between the magnetic core and the normally closed reed switch is related to the magnitude of the surge current and the electromagnetic force required to open the contacts of the normally closed reed switch. In the technical solutions of this application, the design of the distance between the magnetic core coil and the normally closed reed switch allows for better coordination between them, thereby providing protection against continuous or pulsed surges.

[0013] In some embodiments, the buffer delay circuit includes a switching transistor, an energy storage capacitor, a first resistor, and a second resistor. The control electrode of the switching transistor is connected to the first terminal of the second resistor. The first electrode of the switching transistor is connected to the first terminal of the coil, the first terminal of the energy storage capacitor, and the first terminal of the first resistor, respectively. The second electrode of the switching transistor is connected to the second terminal of a normally closed reed switch. The second terminals of the first resistor, the energy storage capacitor, and the second resistor are all grounded. In the technical solution of this application embodiment, the charging process of the energy storage capacitor is used to control the opening and closing of the switching transistor, thereby achieving the functions of current buffering and delay, which can protect the flexible circuit board and the battery cell monitoring unit.

[0014] In some embodiments, the buffer time of the buffer delay circuit is greater than the response time of the normally closed reed switch. In the technical solution of this application embodiment, the buffer time of the buffer delay circuit is greater than the response time of the normally closed reed switch, which can ensure that the normally closed reed switch can play a role in protecting against surges within the buffer time. At the same time, the buffer delay circuit can also protect the battery cell monitoring unit.

[0015] In some embodiments, the buffer delay circuit has a buffer time greater than 5ms.

[0016] Secondly, this application also provides an energy storage device, which includes a battery module, a cell monitoring unit, and a flexible circuit board as described in any of the first aspects.

[0017] In the technical solution of this application embodiment, each protection circuit on the flexible circuit board includes a fuse, a normally closed reed switch, a magnetic core coil, and a buffer delay circuit. If a continuous or pulse-type surge occurs in the circuit, the magnetic core coil generates a magnetic field, causing the normally closed reed switch to open, thus providing overcurrent protection for the flexible circuit board. When the current in the circuit returns to normal, the magnetic field generated by the magnetic core coil is insufficient to open the normally closed reed switch, and the normally closed reed switch can then conduct the connection between the battery module and the cell monitoring unit, allowing the cell monitoring unit to monitor the battery module normally. In this case, the fuse on the cell monitoring unit does not need to blow, and the cell monitoring unit does not need to be replaced. Furthermore, the normally closed reed switch conducts the connection between the battery module and the cell monitoring unit, and the buffer delay circuit can buffer the current, protecting the cell monitoring unit and reducing damage to the cell monitoring unit from overcurrent. Therefore, each protection circuit on the flexible circuit board can provide overcurrent protection for the corresponding analog front-end circuits connected to the flexible circuit board and the cell monitoring unit, thereby improving the reliability and safety of the energy storage device. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the alternative embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0019] Figure 1 This is one of the structural schematic diagrams of a flexible circuit board according to an embodiment of this application;

[0020] Figure 2 This is a second schematic diagram of the structure of a flexible circuit board according to an embodiment of this application;

[0021] Figure 3 This is the third schematic diagram of the structure of a flexible circuit board according to an embodiment of this application;

[0022] Figure 4 This is the fourth schematic diagram of the structure of a flexible circuit board according to an embodiment of this application;

[0023] Figure 5 This is a schematic diagram of the structure of an energy storage device according to an embodiment of this application.

[0024] Explanation of reference numerals in the attached figures:

[0025] 10. Flexible circuit board; 20. Cell monitoring unit; 30. Battery module;

[0026] 11. Fuse; 12. Normally closed reed switch; 13. Magnetic core coil;

[0027] 13. Buffer delay circuit; 14. First circuit board; 15. Second circuit board;

[0028] 16. Third circuit board; 121. First wire; 122. Second wire; 123. Magnetic core;

[0029] 17. First protective casing; 18. Second protective casing; M. Switching transistor; C. Energy storage capacitor;

[0030] R1, first resistor; R2, second resistor; Gnd, ground. Detailed Implementation

[0031] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0033] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0036] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0037] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0038] With the development of new energy technologies, batteries are being used in an increasingly wide range of fields. For example, they are used in battery-powered new energy vehicles, intelligent robots, and drones, and batteries can also be used to form energy storage systems.

[0039] A battery pack typically includes a battery module, a CSC (Cell Supervisory Circuit), and an FPC (Flexible Printed Circuit). Both the CSC and FPC are equipped with fuses. In the event of an abnormally large current in the circuit, the fuse on the CSC will blow before the fuse on the FPC, thus protecting the fuse on the FPC.

[0040] This method provides good protection against single large current surges; however, if the fuse on the CSC blows, the CSC needs to be replaced. Therefore, this method does not provide protection against continuous or pulsed surges.

[0041] To address the aforementioned problems, this application provides a flexible circuit board, which includes a fuse, a normally closed reed switch, a magnetic core coil, and a buffer delay circuit. If a continuous or pulse-type surge occurs in the circuit, the magnetic core coil generates a magnetic field, causing the normally closed reed switch to open, thus protecting the flexible circuit board from overcurrent. When the current in the circuit returns to normal, the magnetic field generated by the magnetic core coil is insufficient to open the normally closed reed switch, allowing it to reconnect the battery module and the cell monitoring unit, enabling the cell monitoring unit to monitor the battery module normally. In this case, the fuse on the cell monitoring unit does not need to blow, and the cell monitoring unit does not need to be replaced. Furthermore, the normally closed reed switch connects the battery module and the cell monitoring unit, and the buffer delay circuit buffers the current, protecting the cell monitoring unit and reducing damage from overcurrent.

[0042] According to some embodiments of this application, refer to Figure 1 A flexible circuit board is provided. The flexible circuit board 10 includes a fuse, a normally closed reed switch 11, a magnetic core coil 12, and a buffer delay circuit 13. The first end of the fuse is connected to the cell monitoring unit 20, and the second end of the fuse is connected to the first end of the normally closed reed switch 11. The second end of the normally closed reed switch 11 is connected to the first end of the buffer delay circuit 13. The second end of the buffer delay circuit 13 is connected to the first end of the magnetic core coil 12. The second end of the magnetic core coil 12 is connected to the battery module 30, and the distance between the magnetic core coil 12 and the normally closed reed switch 11 is within a preset distance range. The magnetic core coil 12 is used to generate a magnetic field according to the continuous or pulse-type surge current flowing through the magnetic core coil. The normally closed reed switch 11 is used to disconnect the connection between the cell monitoring unit 20 and the battery module 30 driven by the magnetic field. The buffer delay circuit 13 is used to delay the connection between the battery module 30 and the normally closed reed switch 11.

[0043] In this embodiment, the flexible circuit board 10 includes a fuse, a normally closed reed switch 11, a magnetic core coil 12, and a buffer delay circuit 13.

[0044] The first end of the fuse is connected to the cell monitoring unit 20, and the second end of the fuse is connected to the first end of the normally closed reed switch 11. The second end of the normally closed reed switch 11 is connected to the first end of the buffer delay circuit 13. The second end of the buffer delay circuit 13 is connected to the first end of the magnetic core coil 12. The second end of the magnetic core coil 12 is connected to the battery module 30.

[0045] The normally closed reed switch 11 described above is an electrical switch that operates based on a magnetic field. Its basic design involves sealing two magnetic reeds inside a glass tube, with the two reeds overlapping. When there is no external magnetic field or the magnetic field strength is weak, the two magnetic reeds are in contact, and the normally closed reed switch 11 conducts the circuit connected to its two ends. When an external magnetic field is generated and its strength exceeds a preset strength threshold, the two magnetic reeds spring open, and the normally closed reed switch 11 disconnects the circuit connected to its two ends.

[0046] The magnetic core coil 12 generates a magnetic field based on the current flowing through it. If a continuous or pulse-type surge current occurs, that is, if the current flowing through the magnetic core coil is large, the generated magnetic field strength is strong. If the current flowing through the magnetic core coil is small, the generated magnetic field strength is weak.

[0047] The aforementioned fuse is an electrical appliance that breaks the circuit by melting the fusible element when the current exceeds a specified value, using the heat generated by the fuse itself.

[0048] During normal operation, a path is formed from the battery module 30 to the magnetic core coil 12, the buffer delay circuit 13, the normally closed reed switch 11, the fuse, and then to the cell monitoring unit 20, which monitors the battery module 30.

[0049] If a continuous or pulsed surge occurs in the above-mentioned path, the magnetic core coil 12 will generate a magnetic field, which will cause the normally closed reed switch 11 to disconnect the connection between the battery module 30 and the cell monitoring unit 20, thereby preventing the surge from damaging the devices on the flexible circuit board 10 and the cell monitoring unit 20, and providing overcurrent protection for the flexible circuit board 10 and the cell monitoring unit 20.

[0050] If the current output by battery module 30 returns to normal, and the magnetic field generated by magnetic core coil 12 is insufficient to disconnect normally closed reed switch 11, then normally closed reed switch 11 will reconnect the connection between battery module 30 and cell monitoring unit 20, allowing cell monitoring unit 20 to monitor battery module 30 normally. During the process of normally closed reed switch 11 reconnecting the connection between battery module 30 and cell monitoring unit 20, buffer delay circuit 13 delays the connection between battery module 30 and normally closed reed switch 11, thereby buffering the current output by battery module 30, protecting cell monitoring unit 20, and reducing overcurrent damage to cell monitoring unit 20.

[0051] If the output current of the battery module 30 exceeds the specified value, the fuse on the flexible circuit board 10 will blow, thereby protecting the flexible circuit board 10 and the cell monitoring unit 20.

[0052] In some embodiments, the distance between the magnetic core coil 12 and the normally closed reed switch 11 is within a preset distance range. This distance can ensure that the magnetic field strength generated by the magnetic core coil 12 is sufficient to drive the normally closed reed switch 11 to turn off when the surge current exceeds a preset current threshold, and can also reduce the magnetic field strength generated by the magnetic core coil 12 when the current is normal, so that the normally closed reed switch 11 can turn on.

[0053] In the technical solution of this application embodiment, if a continuous or pulse-type surge occurs in the circuit, the magnetic core coil generates a magnetic field, causing the normally closed reed switch to open, thus providing overcurrent protection for the flexible circuit board. When the current in the circuit returns to normal, the magnetic field generated by the magnetic core coil is insufficient to open the normally closed reed switch, allowing it to reconnect the battery module and the cell monitoring unit, enabling the cell monitoring unit to monitor the battery module normally. In this case, the fuse on the cell monitoring unit does not need to blow, and the cell monitoring unit does not need to be replaced. Furthermore, the normally closed reed switch connecting the battery module and the cell monitoring unit allows the buffer delay circuit to buffer current, protecting the cell monitoring unit and reducing overcurrent damage.

[0054] According to some embodiments of this application, refer to Figure 2 The flexible circuit board 10 also includes a first circuit board 14, a second circuit board 15, and a third circuit board 16. The magnetic core coil 12 includes a first wire 121 disposed in the first circuit board 14, a second wire 122 disposed in the second circuit board 15, and a magnetic core 123. The first circuit board 14 and the second circuit board 15 are stacked, the first wire 121 and the second wire 122 are symmetrically arranged to form a coil, the first end of the coil is connected to the second end of the buffer delay circuit 13, and the second end of the coil is connected to the battery module 30. The magnetic core 123 is disposed between the first circuit board 14 and the second circuit board 15 and is located at the center of the coil. The third circuit board 16 is disposed adjacent to the side of the first circuit board 14 and the second circuit board 15, and the normally closed reed switch 11 is disposed inside the third circuit board 16. The distance between the magnetic core 123 and the normally closed reed switch 11 is within a preset distance range.

[0055] In this embodiment, the flexible circuit board 10 further includes a first circuit board 14, a second circuit board 15, and a third circuit board 16. The first circuit board 14 and the second circuit board 15 are stacked, and the third circuit board 16 is disposed adjacent to the side of the first circuit board 14 and the second circuit board 15. A normally closed reed switch 11 is disposed inside the third circuit board 16.

[0056] The magnetic core coil 12 includes a first conductor 121, a second conductor 122, and a magnetic core 123. The first conductor 121 is disposed in a first circuit board 14, and the second conductor 122 is disposed in a second circuit board 15. The first conductor 121 and the second conductor 122 are symmetrically arranged to form a coil. The magnetic core 123 is disposed between the first circuit board 14 and the second circuit board 15, and is located at the center of the coil.

[0057] The first end of the coil is connected to the second end of the buffer delay circuit 13, and the second end of the coil is connected to the battery module 30. If the output current of the battery module 30 experiences a continuous or pulse-type surge, the coil will generate a magnetic field. This magnetic field will cause the normally closed reed switch 11 to disconnect the connection between the battery module 30 and the cell monitoring unit 20, thus preventing the surge from damaging the flexible circuit board 10 and the cell monitoring unit 20, and providing overcurrent protection for the flexible circuit board 10 and the cell monitoring unit 20.

[0058] If the output current of the battery module 30 returns to normal, and the magnetic field generated by the coil is insufficient to turn off the normally closed reed switch 11, then the normally closed reed switch 11 will reconnect the battery module 30 and the cell monitoring unit 20, so that the cell monitoring unit 20 can monitor the battery module 30 normally.

[0059] In some embodiments, the distance between the magnetic core 123 and the normally closed reed switch 11 is within a preset distance range, that is, the distance between the coil and the normally closed reed switch 11 is limited, so that when the surge current exceeds the preset current threshold, the magnetic field strength generated by the coil is sufficient to drive the normally closed reed switch 11 to turn off, and when the current is normal, the magnetic field strength generated by the coil can be reduced, and the normally closed reed switch 11 can be turned on.

[0060] In the technical solution of this application embodiment, the normally closed reed switch and magnetic core coil are embedded in the flexible circuit board, which can reduce the overall volume occupied by the flexible circuit board.

[0061] According to some embodiments of this application, refer to Figure 3 The flexible circuit board 10 also includes a first protective shell 17 and a second protective shell 18; the first protective shell 17 covers the first surface of the first circuit board 14 away from the second circuit board 15, and covers the second surface of the third circuit board 16 that is flush with the first surface; the second protective shell 18 covers the third surface of the second circuit board 15 away from the first circuit board 14, and covers the fourth surface of the third circuit board 16 that is flush with the third surface.

[0062] In this embodiment of the application, considering that the magnetic field generated by the magnetic core may cause electromagnetic interference to other devices, a first protective shell 17 and a second protective shell 18 for shielding interference can be provided.

[0063] The first circuit board 14 is disposed on a first surface away from the second circuit board 15 and flush with the second surface of the third circuit board 16. A first protective shell 17 covers the first and second surfaces. The second circuit board 15 is disposed on a third surface away from the first circuit board 14 and flush with the fourth surface of the third circuit board 16. A second protective shell 18 covers the third and fourth surfaces.

[0064] In the technical solution of this application embodiment, the first protective shell and the second protective shell wrap the upper and lower surfaces of the normally closed reed switch and magnetic core coil of the flexible circuit board, which can reduce the interference of the magnetic field generated by the electromagnetic coil on other devices on the flexible circuit board, thereby improving the reliability of the flexible circuit board.

[0065] According to some embodiments of this application, the materials of the first protective shell 17 and the second protective shell 18 include copper.

[0066] In the embodiments of this application, metals, composite materials, conductive polymer materials, etc., can be used to shield electromagnetic interference.

[0067] Metals that can be used include copper, copper alloys, aluminum, aluminum alloys, iron, and iron alloys (including steel). Among these, copper and copper alloys not only have excellent electrical conductivity and good shielding effect against high-frequency electromagnetic waves, but also high ductility, making them easy to process into sheets, foils, or meshes. Aluminum alloys are lightweight (approximately 1 / 3 the density of copper), have lower costs, and good electrical conductivity; anodizing can improve corrosion resistance, but their shielding effectiveness is slightly lower than copper, and their shielding effect against low-frequency magnetic fields is weaker. Iron and iron alloys have strong magnetic permeability, providing excellent shielding against low-frequency magnetic fields (such as 50Hz power frequency magnetic fields); they are low in cost and high in strength. However, they are prone to rust (requiring galvanizing or painting).

[0068] Composite materials can utilize metal-coated materials, metal mesh / metal fabrics, etc. Metal-coated materials typically involve plating a layer of metal (copper, nickel, silver, etc.) onto the surface of a non-metallic substrate (such as plastic or ceramic) to achieve conductivity and shielding. Metal mesh / metal fabrics are woven from metal wires (copper, steel, nickel), offering good flexibility and breathability.

[0069] Conductive polymer materials can include conductive plastics and conductive rubbers. Conductive plastics are plastics mixed with conductive fillers (such as carbon powder, metal powder, and carbon fiber) to form a conductive network. They are lightweight, easy to injection mold, and offer moderate shielding effectiveness (depending on the filler content). Conductive rubbers are rubber base materials with added conductive particles (such as carbon black and silver powder), combining elasticity and conductivity, making them suitable for applications requiring integrated sealing and shielding.

[0070] In practical applications, other special shielding materials may also be used, but this application does not limit the specific materials used.

[0071] In some embodiments, depending on the dimensions of the normally closed reed switch 11 and the magnetic core coil 12, the coverage area of ​​the first protective shell 17 and the second protective shell 18 is greater than 100 cm². 2 .

[0072] In the technical solution of this application embodiment, the first protective shell and the second protective shell are made of copper, which has a good shielding effect on high-frequency electromagnetic waves, and is easy to process and has a moderate cost.

[0073] According to some embodiments of this application, the number of turns of the coil is proportional to the ampere-turns of the normally closed reed switch 11 and the magnitude of the surge current.

[0074] In this embodiment, the relationship between the number of turns of the coil and the ampere-turns of the normally closed reed switch 11 is as follows:

[0075] AT=I×N---------------------------------------------(1);

[0076] Where AT is the ampere-turns of the normally closed reed switch 11, and I is the current. In some embodiments, a normally closed reed switch 11 with an ampere-turns of 60 is selected. Assuming that the surge current is greater than 30A and the normally closed reed switch 11 needs to be disconnected, the number of turns of the coil in the magnetic core coil 12 is calculated according to the above formula: N = 60 / 30 = 2 turns.

[0077] In the technical solution of this application embodiment, the number of turns of the coil is set according to the selection of the normally closed reed switch and the magnitude of the current to be protected, so that the magnetic core coil and the normally closed reed switch can be well matched, and the coil can be protected against continuous or pulse surges.

[0078] According to some embodiments of this application, the distance between the magnetic core 123 and the normally closed reed switch 11 is related to the magnitude of the surge current and the electromagnetic force required to open the contacts of the normally closed reed switch 11.

[0079] In this embodiment, when a large instantaneous current flows through the magnetic core coil 12, the coil generates a magnetic field, causing the contacts of the normally closed reed switch 11 to open.

[0080] The formula for electromagnetic force is as follows:

[0081] F=BIL----------------------------------(2);

[0082] Where F is the electromagnetic force on the current-carrying conductor, B is the magnetic induction intensity of the magnetic field, I is the current flowing through the conductor, and L is the effective length of the conductor in the magnetic field. Understandably, when the current I flowing through the magnetic core coil 12 increases instantaneously, the magnetic field strength increases, the two contacts of the normally closed reed switch 11 acquire the same polarity, and the contacts open. The distance d between the normally closed reed switch 11 and the magnetic core coil 12 is calculated experimentally based on the electromagnetic force required to disconnect the normally closed reed switch 11 from the current I.

[0083] For example, when the distance between the normally closed reed switch 11 and the magnetic core coil 12 is d=2nm, and the surge current is greater than 1A, the electromagnetic force generated on the normally closed reed switch 11 is greater than the inherent closing mechanical force of the normally closed reed switch 11, and the contacts of the normally closed reed switch 11 pop open; when the current is less than 1A, the generated electromagnetic force is insufficient to make the contacts of the normally closed reed switch 11 pop open.

[0084] In the technical solution of this application embodiment, the distance between the magnetic core coil and the normally closed reed switch is designed so that the magnetic core coil and the normally closed reed switch can be better matched, thereby providing protection against continuous or pulse surges.

[0085] According to some embodiments of this application, refer to Figure 4The buffer delay circuit 13 includes a switching transistor M, an energy storage capacitor C, a first resistor R1, and a second resistor R2. The control terminal of the switching transistor M is connected to the first end of the second resistor R2. The first terminal of the switching transistor M is connected to the first end of the coil, the first end of the energy storage capacitor C, and the first end of the first resistor R1. The second terminal of the switching transistor M is connected to the second end of the normally closed reed switch 11. The second ends of the first resistor R1, the second end of the energy storage capacitor C, and the second end of the second resistor R2 are all grounded to Gnd.

[0086] In this embodiment, the buffer delay circuit 13 includes a switching transistor M, an energy storage capacitor C, a first resistor R1, and a second resistor R2.

[0087] When the switching transistor M is a PMOS transistor, the control terminal of the switching transistor M is connected to the first terminal of the second resistor R2. The first terminal of the switching transistor M is connected to the first terminal of the coil, the first terminal of the energy storage capacitor C, and the first terminal of the first resistor R1. The second terminal of the switching transistor M is connected to the second terminal of the normally closed reed switch 11. The second terminals of the first resistor R1, the second terminal of the energy storage capacitor C, and the second terminal of the second resistor R2 are all grounded to Gnd.

[0088] When a surge current occurs, the energy storage capacitor C is charged through the first resistor R1. If the voltage difference across the energy storage capacitor C is not greater than the turn-on voltage of the switching transistor M, the switching transistor M is turned off, disconnecting the connection between the battery module 30 and the cell monitoring unit 20. As charging progresses, the voltage difference across the energy storage capacitor C exceeds the turn-on voltage of the switching transistor M, causing the switching transistor M to reconnect the battery module 30 and the cell monitoring unit 20, allowing the cell monitoring unit 20 to monitor the battery module 30.

[0089] In other embodiments, the switch M is an NMOS transistor, requiring adaptive adjustments to the connection relationship of the switch M.

[0090] In some embodiments, the energy storage capacitor C can be replaced by an inductor, or an RL circuit composed of an inductor and a resistor. In other embodiments, the buffer delay circuit 13 can be constructed using a D flip-flop, a delay circuit, etc. The embodiments of this application do not limit the structure of the buffer delay circuit 13, and it can be set according to actual conditions.

[0091] In the technical solution of this application embodiment, the charging process of the energy storage capacitor is used to control the opening and closing of the switching transistor, thereby achieving the functions of current buffering and delay, which can protect the flexible circuit board and the cell monitoring unit.

[0092] According to some embodiments of this application, the buffer delay circuit 13 has a buffer time greater than the response time of the normally closed reed switch 11.

[0093] In this embodiment, the buffer time T1 of the buffer delay circuit 13 is equal to R1C, where R1 is the first resistor and C is the energy storage capacitor C. The buffer time is the time required for the energy storage capacitor C to fully charge. The response time T2 of the normally closed reed switch 11 is the time it takes for the magnetic field strength to cause the reed of the normally closed reed switch 11 to open. The response time of the normally closed reed switch 11 is typically in the millisecond range. In some embodiments, the threshold for the response time is 5ms.

[0094] The buffer delay circuit 13 has a buffer time greater than the response time of the normally closed reed switch 11. In some embodiments, the buffer delay circuit 13 has a buffer time greater than 5ms. This ensures that the normally closed reed switch 11 can play a role in protecting against surges within the buffer time. At the same time, the buffer delay circuit 13 can also protect the battery cell monitoring unit 20.

[0095] The response time of the normally closed reed switch 11 is related to the magnetic field strength and the material properties of the normally closed reed switch 11 itself. The relevant function of the response time of the normally closed reed switch 11 can be determined by experiment. By adjusting the selection of the buffer delay circuit 13, the flexible circuit board 10 can be adapted to various application scenarios.

[0096] In the technical solution of this application embodiment, the buffer delay circuit has a buffer time that is greater than the response time of the normally closed reed switch, which can ensure that the normally closed reed switch can play a role in protecting against surges within the buffer time. At the same time, the buffer delay circuit can also protect the battery cell monitoring unit.

[0097] According to some embodiments of this application, refer to Figure 5 An energy storage device is provided. The energy storage device includes a battery module 30, a cell monitoring unit 20, and a flexible circuit board 10 as described in the above embodiment.

[0098] In this embodiment, the energy storage device includes a battery module 30, a cell monitoring unit 20, and a flexible circuit board 10 as described in the above embodiment.

[0099] The battery module 30 includes multiple batteries connected in series; the cell monitoring unit 20 includes multiple AFEs (Analog Front Ends) 21; the flexible circuit board 10 includes multiple protection circuits, each protection circuit including a fuse, a normally closed reed switch 11, a magnetic core coil 12, and a buffer delay circuit 13. In each protection circuit, the fuse is connected to one of the AFEs 21 in the cell monitoring unit 20, and the magnetic core coil 12 is connected to the positive terminal of one of the batteries in the battery module 30.

[0100] For example, the battery module 30 includes N batteries, the cell monitoring unit 20 includes N AFE21s, and the flexible circuit board 10 includes N protection circuits. The fuse in the first protection circuit is connected to the first AFE21, and the magnetic core coil 12 in the first protection circuit is connected to the positive terminal of the first battery; the fuse in the second protection circuit is connected to the second AFE21, and the magnetic core coil 12 in the second protection circuit is connected to the positive terminal of the second battery; and so on, the fuse in the Nth protection circuit is connected to the Nth AFE21, and the magnetic core coil 12 in the Nth protection circuit is connected to the positive terminal of the Nth battery.

[0101] During normal operation, a path is formed from the positive terminal of a battery in the battery module 30 to a protection circuit on the flexible circuit board 10, and then to an AFE21 in the cell monitoring unit 20. The AFE21 monitors the corresponding connected battery in the battery module 30.

[0102] If a continuous or pulsed surge occurs in the circuit, the magnetic core coil 12 in the protection circuit will generate a magnetic field. This magnetic field will cause the normally closed reed switch 11 to disconnect the connection between the battery and AFE21, thereby preventing the surge from damaging the devices on the flexible circuit board 10 and providing overcurrent protection for the flexible circuit board 10.

[0103] If the current in the circuit returns to normal, the magnetic field generated by the magnetic core coil 12 is insufficient to disconnect the normally closed reed switch 11. The normally closed reed switch 11 then reconnects the battery to AFE21, allowing AFE21 to monitor the battery normally. During the process of the normally closed reed switch 11 connecting the battery to AFE21, the buffer delay circuit 13 delays the connection between the battery module 30 and the normally closed reed switch 11, thereby buffering the current output by the battery module 30 and protecting AFE21, reducing damage from overcurrent.

[0104] If the current in the circuit exceeds a specified value, the fuse can blow, thereby protecting the flexible circuit board 10 and AFE21.

[0105] In the technical solution of this application embodiment, each protection circuit on the flexible circuit board can provide overcurrent protection for the AFE connected to the corresponding flexible circuit board and the cell monitoring unit, thereby improving the reliability and safety of the energy storage device.

[0106] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A flexible circuit board, characterized in that, The flexible circuit board includes a fuse, a normally closed reed switch, a magnetic core coil, and a buffer delay circuit. The first end of the fuse is connected to the cell monitoring unit outside the flexible circuit board, and the second end of the fuse is connected to the first end of the normally closed reed switch. The second end of the normally closed reed switch is connected to the first end of the buffer delay circuit. The second end of the buffer delay circuit is connected to the first end of the magnetic core coil; The second end of the magnetic core coil is connected to the battery module, and the distance between the magnetic core coil and the normally closed reed switch is within a preset distance range; The magnetic core coil is used to generate a magnetic field based on the continuous or pulsed surge current flowing through the magnetic core coil; The normally closed reed switch is used to disconnect the cell monitoring unit from the battery module when driven by the magnetic field. The buffer delay circuit is used to delay the connection between the battery module and the normally closed reed switch.

2. The flexible circuit board according to claim 1, characterized in that, The flexible circuit board further includes a first circuit board, a second circuit board, and a third circuit board, and the magnetic core coil includes a first wire disposed in the first circuit board, a second wire disposed in the second circuit board, and a magnetic core; The first circuit board and the second circuit board are stacked, the first wire and the second wire are symmetrically arranged to form a coil, the first end of the coil is connected to the second end of the buffer delay circuit, and the second end of the coil is connected to the battery module. The magnetic core is disposed between the first circuit board and the second circuit board, and is located at the center of the coil; The third circuit board is disposed adjacent to the side of the first circuit board and the second circuit board, and the normally closed reed switch is disposed inside the third circuit board; The distance between the magnetic core and the normally closed reed switch is within the preset distance range.

3. The flexible circuit board according to claim 2, characterized in that, The flexible circuit board also includes a first protective shell and a second protective shell; The first protective shell covers the first surface of the first circuit board away from the second circuit board, and also covers the second surface of the third circuit board that is flush with the first surface; The second protective shell covers the third surface of the second circuit board away from the first circuit board, and also covers the fourth surface of the third circuit board that is flush with the third surface.

4. The flexible circuit board according to claim 3, characterized in that, The materials of the first protective shell and the second protective shell include copper.

5. The flexible circuit board according to any one of claims 2-4, characterized in that, The number of turns of the coil is proportional to the ampere-turns of the normally closed reed switch and the magnitude of the surge current.

6. The flexible circuit board according to any one of claims 2-4, characterized in that, The distance between the magnetic core and the normally closed reed switch is related to the magnitude of the surge current and the electromagnetic force required to open the contacts of the normally closed reed switch.

7. The flexible circuit board according to claim 2, characterized in that, The buffer delay circuit includes a switching transistor, an energy storage capacitor, a first resistor, and a second resistor. The control electrode of the switching transistor is connected to the first end of the second resistor, the first electrode of the switching transistor is connected to the first end of the coil, the first end of the energy storage capacitor and the first end of the first resistor respectively, and the second electrode of the switching transistor is connected to the second end of the normally closed reed switch. The second end of the first resistor, the second end of the energy storage capacitor, and the second end of the second resistor are all grounded.

8. The flexible circuit board according to claim 7, characterized in that, The buffer delay circuit has a buffer time that is greater than the response time of the normally closed reed switch.

9. The flexible circuit board according to claim 8, characterized in that, The buffer delay circuit has a buffer time of more than 5ms.

10. An energy storage device, characterized in that, The energy storage device includes a battery module, a cell monitoring unit, and a flexible circuit board as described in any one of claims 1-9.

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