Overcurrent protection components and battery systems

Abstract

To simplify connection operations and improve reliability by suppressing poor contact during connection, the overcurrent protection element includes: a chip fuse (11); a printed circuit board on which the chip fuse (11) is mounted; an external connection portion (13) connected to the printed circuit board; and an insulating layer (15) disposed on the printed circuit board. The printed circuit board has conductive portions disposed on the surface of an insulating substrate. The external connection portion (13) is electrically connected to the conductive portions of the printed circuit board. The chip fuse (11) is electrically connected to the conductive portions, and the chip fuse (11) is connected to the external connection portion (13) via the conductive portions.

Description

Technical Field

[0001] The present invention relates to an overcurrent protection element having a fuse that will blow due to excessive current and a battery system having the overcurrent protection element. Background Technology

[0002] Fuse, as an overcurrent protection element that melts upon the flow of overcurrent, is used in various applications. For example, it is used as an overcurrent protection element in the current sensing line of a battery system consisting of multiple batteries connected in series. In this battery system, the charging and discharging of the batteries is controlled by detecting the voltage of each battery, thereby protecting the batteries and ensuring system safety. In this application, the fuse used as an overcurrent protection element is connected to a voltage sensing line, which connects the batteries constituting the battery system to a voltage detection circuit that detects the voltage of each battery. The voltage detection circuit detects and controls the voltage of each battery via the voltage sensing line, limiting the charging and discharging current or prohibiting charging and discharging when the battery voltage exceeds a set range, and also equalizing the voltage of each battery, thereby protecting the battery and ensuring safety. Battery systems used as power sources for vehicles and uninterruptible power supplies for servers require extremely high instantaneous output; therefore, a large number of batteries are connected in series to increase the output voltage. For such battery systems, reliably detecting the voltage of a large number of batteries to control charging and discharging to ensure safety is crucial.

[0003] In a battery system that controls the charging and discharging current by detecting the voltage of each battery, each electrode terminal is connected to the voltage detection circuit via voltage detection lines. Since the voltage of all batteries is detected in the battery system, the number of voltage detection lines increases proportionally to the number of batteries. For example, a battery system consisting of 20 batteries connected in series requires 21 voltage detection lines to connect each battery to the voltage detection circuit. With a large number of voltage detection lines crammed into a confined space, miniaturization of overcurrent protection components becomes crucial. Furthermore, since each voltage detection line is connected to the battery electrode terminal at one end, a short circuit due to casing damage or assembly errors can lead to overcurrent and compromise safety. To prevent this drawback, a power supply device has been developed that incorporates fuses as overcurrent protection components for each voltage detection line. (Refer to Patent Document 1)

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-220377 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In overcurrent protection components connected midway through voltage detection lines, leads are connected to both ends of a lead-type fuse via crimp terminals with a riveted construction. Heat-shrink tubing is used to insulate both the fuse and the crimp terminals. In this type of fuse, leads are connected to the fuse via crimp terminals, and the ends of these leads are connected to the battery terminals or the voltage detection circuit via methods such as brazing. Because this fuse has crimp terminals with a riveted construction at both ends and is covered by heat-shrink tubing, it becomes thick and cannot be compactly arranged. Therefore, considerable effort is required to configure a large number of voltage detection lines within a narrow area of ​​the system, and the riveted connection method makes it difficult to completely prevent contact failures over extended periods. A poor fuse connection is essentially equivalent to a blown fuse, thus leading to significant drawbacks in all operating environments, such as the inability to reliably detect battery voltage.

[0009] The present invention was developed with the aim of eliminating the above-mentioned disadvantages of conventional fuses. Therefore, an important objective of the present invention is to provide an overcurrent protection element that can simplify connection work and suppress poor contact during connection to improve reliability, and a battery system equipped with the overcurrent protection element.

[0010] Solution for solving the problem

[0011] An overcurrent protection element according to one aspect of the present invention includes: a chip fuse 11; a printed circuit board 12 on which the chip fuse 11 is mounted; an external connection portion 13 connected to the printed circuit board 12; and an insulating layer 15 disposed on the printed circuit board 12. The printed circuit board 12 has conductive portions 12B disposed on the surfaces of insulating substrates 12A and 12C. The external connection portion 13 is electrically connected to the conductive portions 12B of the printed circuit board 12. The chip fuse 11 is electrically connected to the conductive portions 12B, and the chip fuse 11 is connected to the external connection portion 13 via the conductive portions 12B.

[0012] The battery system according to other embodiments of the present invention includes: a plurality of battery cells 1; a busbar 3, which is a metal plate fixed to the electrode terminals 2 of the battery cells 1 to connect the battery cells 1; and a voltage detection circuit 5, which is connected to the busbar 3 via voltage detection lines 4 having overcurrent protection elements 10, 20, 30, 40, and 50. The overcurrent protection elements 10, 20, 30, 40, and 50 include: a chip fuse 11; a printed circuit board 12 on which the chip fuse 11 is mounted; an external connection portion 13 connected to the printed circuit board 12; and an insulating layer 15 disposed on the printed circuit board 12. The printed circuit board 12 has conductive portions 12B disposed on the surfaces of insulating substrates 12A and 12C, and the external connection portion 13 is electrically connected to the conductive portions 12B of the printed circuit board 12. The chip fuse 11 is electrically connected to the conductive part 12B. The chip fuse 11 is connected to the external connection part 13 via the conductive part 12B. The external connection part 13 is connected to the voltage detection line 4.

[0013] The effects of the invention

[0014] The overcurrent protection element and battery system of the present invention have the characteristics of simplifying the connection operation of the overcurrent protection element and improving reliability by suppressing poor contact during connection. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of a battery system according to one embodiment of the present invention.

[0016] Figure 2 This is an enlarged perspective view of a battery system according to one embodiment of the present invention.

[0017] Figure 3 This is a perspective view of an overcurrent protection element according to one embodiment of the present invention.

[0018] Figure 4 yes Figure 3 An exploded perspective view of the overcurrent protection element shown.

[0019] Figure 5 This is a perspective view of an overcurrent protection element according to other embodiments of the present invention.

[0020] Figure 6 This is a perspective view of an overcurrent protection element according to other embodiments of the present invention.

[0021] Figure 7 yes Figure 6 An exploded perspective view of the overcurrent protection element shown.

[0022] Figure 8 This is a cross-sectional view showing another example of an insulating plastic molded body.

[0023] Figure 9 It means Figure 7 A top view showing the manufacturing process of the overcurrent protection element.

[0024] Figure 10 This is a top view of an overcurrent protection element according to other embodiments of the present invention.

[0025] Figure 11 This is a perspective view of an overcurrent protection element according to other embodiments of the present invention.

[0026] Figure 12 It means Figure 11 A perspective view showing an example of the operating state of an overcurrent protection element. Detailed Implementation

[0027] The invention will now be described in detail with reference to the accompanying drawings. Furthermore, in the following description, terms indicating specific directions and positions (e.g., "upper," "lower," and other terms including these terms) are used as needed; however, the use of these terms is for ease of understanding of the invention with reference to the drawings and does not limit the technical scope of the invention by their meaning. Additionally, the same symbols shown in the various drawings represent the same or equivalent parts or components.

[0028] Furthermore, the embodiments shown below are specific examples illustrating the technical concept of the present invention and are not intended to limit the present invention. Additionally, unless specifically stated, the dimensions, materials, shapes, and relative arrangements of the structural components described below are not intended to limit the scope of the present invention, but are merely illustrative. Furthermore, the content described in one embodiment or example can be applied to other embodiments or examples. Also, for clarity, there may be instances where the size and positional relationships of the components shown in the drawings are exaggerated.

[0029] The overcurrent protection element of the first invention comprises: a chip fuse; a printed circuit board on which the chip fuse is mounted; an external connection portion connected to the printed circuit board; and an insulating layer disposed on the printed circuit board, wherein the printed circuit board has a conductive portion disposed on the surface of the insulating substrate, the external connection portion is electrically connected to the conductive portion of the printed circuit board, the chip fuse is electrically connected to the conductive portion, and the chip fuse is connected to the external connection portion via the conductive portion.

[0030] The above-described overcurrent protection element has the following characteristics: Since it does not use crimp terminals with riveted construction or heat-shrink tubing, but instead mounts the chip fuse surface onto a printed circuit board and insulates the surface, and provides an external connection portion on the conductive part of the printed circuit board, allowing electrical connection to the voltage detection line of the battery system, this overcurrent protection element can be easily configured in narrow spaces and assembly is simplified. Furthermore, since it eliminates the need for crimp terminals with riveted construction, it can suppress contact defects that may occur over time with crimp terminals, thus improving reliability. Additionally, it achieves the following features: because the chip fuse is mounted on the printed circuit board, and the external connection portion is electrically connected to the conductive part of the printed circuit board, allowing connection to the voltage detection line, a small chip fuse can be used, and easy, reliable, and stable electrical connection to the voltage detection line is possible. Moreover, the chip fuse can be protected by the printed circuit board or an insulating layer.

[0031] In the second overcurrent protection element of the present invention, the insulating substrate is provided as a planar rigid substrate. The rigid substrate can stably connect to the external connection portion.

[0032] In the overcurrent protection element of the third invention, the insulating substrate is provided as a flexible substrate with flexibility. The flexible substrate can be easily disposed in a narrow space.

[0033] In the fourth overcurrent protection element of this invention, the insulating layer is provided as an insulating plastic molded body bonded to the surface of the printed circuit board. The above-described overcurrent protection element is characterized by its ability to protect the printed circuit board, chip fuse, and external connections through the insulating layer of the insulating plastic molded body.

[0034] In the overcurrent protection element of the fifth invention, the external connection portion is composed of a first external connection portion and a second external connection portion as a pair, and the first external connection portion is a metal plate.

[0035] In the sixth overcurrent protection element of the present invention, the metal plate is configured as a plate connected to the busbar, which is fixed to the electrode terminals of the battery constituting the battery system.

[0036] In the overcurrent protection element of the seventh invention, the second external connection portion is provided as either a metal plate soldered to the conductive portion of the printed circuit board or a lead wire.

[0037] In the overcurrent protection element of the eighth invention, the second external connection part is a metal plate soldered to the conductive part of the printed circuit board and a lead wire connected to the metal plate.

[0038] In the overcurrent protection element of the ninth invention, the insulating plastic molded body has an opening window that exposes the chip fuse, and the opening window is covered by an insulating member.

[0039] In the overcurrent protection element of the tenth invention, the insulating plastic molded body has a retaining portion for the external connection portion. The above-described overcurrent protection element is characterized by strengthening the connection between the printed circuit board and the external connection portion through the insulating plastic molded body, thereby enhancing the connection strength between the two.

[0040] In the overcurrent protection element of the eleventh invention, the insulating plastic molded body is connected to the printed circuit board by a locking structure.

[0041] In the twelfth overcurrent protection element of the present invention, the insulating plastic molded body is fixed in such a way as to clamp the two sides of the printed circuit board.

[0042] In the overcurrent protection element of the thirteenth invention, the external connection part is provided as a connection part connected to the voltage detection line, which detects the voltage of each battery constituting the battery system, which is formed by connecting multiple batteries in series.

[0043] The fourteenth battery system of the present invention comprises: a plurality of battery cells; a busbar, which is a metal plate fixed to the electrode terminals of the battery cells to connect the battery cells; and a voltage detection circuit connected to the busbar via a voltage detection line having an overcurrent protection element. The overcurrent protection element comprises: a chip fuse; a printed circuit board on which the chip fuse is mounted; an external connection portion connected to the printed circuit board; and an insulating layer disposed on the printed circuit board. The printed circuit board has conductive portions disposed on the surface of an insulating substrate. The external connection portion is electrically connected to the conductive portions of the printed circuit board, the chip fuse is electrically connected to the conductive portions, the chip fuse is connected to the external connection portion via the conductive portions, and the external connection portion is connected to the voltage detection line.

[0044] In the battery system of the fifteenth invention, the insulating substrate is either a planar rigid substrate or a flexible substrate.

[0045] In the battery system of the sixteenth invention, the insulating layer is provided as an insulating plastic molded body bonded to the surface of the printed circuit board.

[0046] In the battery system of the seventeenth invention, the insulating layer is provided as an insulating plastic molded body that retains the external connection portion.

[0047] (Implementation Method)

[0048] Figure 1The circuit diagram shows a battery system 100 comprising multiple battery cells 1 and a voltage detection circuit 5 for detecting the voltage of each battery cell 1. In the battery system 100, the charging and discharging current is controlled based on the voltage of each battery cell detected by the voltage detection circuit 5 to protect the battery and ensure safety. This battery system 100 is primarily suitable as a power supply device for supplying power to a motor that powers a vehicle, a power supply device for a server, a power storage device for storing electricity generated by solar panels, or a power storage device for storing electricity generated at night, etc., for large-scale power sources.

[0049] The battery system 100 includes a control circuit 6, which controls charging and discharging based on the battery voltage detected by the voltage detection circuit 5. When the voltage of any battery exceeds a set value, the control circuit 6 cuts off or reduces the charging current to prevent overcharging. Conversely, when the battery voltage is below the set value, the control circuit 6 prohibits discharging or reduces the discharging current to protect the battery from over-discharging. Furthermore, when battery voltages become uneven, specific batteries are discharged or specific batteries are charged to equalize the voltages and suppress the imbalance.

[0050] In battery system 100, such as Figure 2 As shown in the enlarged 3D view, a busbar 3 with a metal plate fixed to the electrode terminal 2 connects the battery cells 1 in series or parallel. A voltage detection circuit 5 is connected to the busbar 3 via a voltage detection line 4 to detect the voltage of each battery. An overcurrent protection element 10 is connected midway along the voltage detection line 4. The overcurrent protection element 10 is connected to the voltage detection line 4 to protect the battery from excessive short-circuit current and ensure safety. Short-circuit current could be caused by operator error during assembly, resulting in a short circuit in the voltage detection line 4, or by damage to the casing causing a short circuit in the voltage detection line 4.

[0051] Figures 3-7 Specific examples of overcurrent protection elements 10, 20, and 30 are shown. Figures 3 to 7 The overcurrent protection elements 10, 20, and 30 include a chip fuse 11 that will melt due to overcurrent, a printed circuit board 12 for surface-mount chip fuse 11, an external connection portion 13 connected to the printed circuit board 12, and an insulating layer 15 disposed on the printed circuit board 12.

[0052] Chip fuse 11 is surface mounted on printed circuit board 12. Chip fuse 11 is rectangular in shape with terminals at both ends and a fuse with a metal wire that will melt due to a set current is arranged inside. The two ends of the fuse are connected to the terminals so that the terminals at both ends can be reflow soldered.

[0053] The printed circuit board 12 has copper foil bonded to the surface of the insulating substrate 12A to form conductive parts 12B. The insulating substrate 12A is a rigid substrate formed by molding epoxy resin or phenolic resin with embedded reinforcing fibers into a planar shape, or a flexible substrate. The rigid substrate can stably connect to the external connection part 13, and the flexible substrate can be easily arranged in narrow spaces.

[0054] The external connection portion 13 is a pair of terminals electrically connected to the conductive portion 12B of the printed circuit board 12, and is composed of a first external connection portion 13A and a second external connection portion 13B. Figures 3 to 7 In the overcurrent protection elements 10, 20, and 30 shown, a first external connection portion 13A is formed by a conductive metal plate 14. The illustrated metal plates 14A and 14C are designed with protrusions 14a that connect to the conductive portion 12B. The protrusions 14a are stacked on the surface of the printed circuit board 12 and are electrically connected to the conductive portion 12B by soldering. Soldering the protrusions 14a to the conductive portion 12B connects the metal plates 14A and 14C to a fixed position on the printed circuit board 12.

[0055] like Figure 2 As shown, the first external connecting portion 13A of the metal plate 14 is fixed to and electrically connected to the busbar 3 of the battery system 100. The busbar 3 is a metal plate that connects the battery cells 1 constituting the battery system 100 in series or parallel. The first external connecting portion 13A is reliably and stably fixed to the fixed position of the battery cell 1 by the overcurrent protection element 10 stacked and fixed to the busbar 3, and is also stably electrically connected with a small resistance. The first external connecting portion 13A is fixed to the busbar 3 by welding or by threading. Alternatively, the first external connecting portion 13A can also be fixed to the busbar 3 by other methods such as riveting.

[0056] Furthermore, in Figures 3 to 6 In the overcurrent protection elements 10 and 20, the second external connection part 13B is also a conductive metal plate 14. The second external connection part 13B of the metal plates 14B and 14D is also designed with a protrusion 14a, and the protrusion 14a is stacked and soldered to the printed circuit board 12. Figure 3 The metal plate 14B shown as the second external connection part 13B is provided with a through hole 14b. The second external connection part 13B of the metal plate 14B with the through hole 14b can be fixed by threading the connection terminal 7 provided at the end of the lead 4A of the voltage detection line 4. Additionally, as... Figure 5 As shown, the lead 4A of the voltage detection line 4 can be laser-welded or ultrasonically connected to the surface of the second external connection portion 13B of the metal plate 14D for electrical connection. Furthermore, in the overcurrent protection element 30, as... Figure 7As shown, a portion of the conductive portion 12B disposed on the surface of the printed circuit board 12 can also be used as a second external connection portion 13B to directly solder the lead 4A of the electrical connection voltage detection line 4 there.

[0057] Figures 3 to 7 The overcurrent protection elements 10, 20, and 30 shown are configured with the following shape: the lateral width of the metal plates 14A and 14C, which serve as the first external connection portion 13A, and the metal plate 14D, which serves as the second external connection portion 13B, is set to the same width as the lateral width of the rectangular printed circuit board 12, and they are disposed at the end of the long side of the printed circuit board 12, and the metal plates 14 do not protrude from the sides of the printed circuit board 12. These overcurrent protection elements 10, 20, and 30 have the following characteristics: the lateral width of the metal plate 14 is increased to create a shape that allows for reliable and stable connection with the busbar 3 and the voltage detection line 4, and it is compact enough to be easily disposed in the narrow space of the battery system 100. In addition, Figure 3 and Figure 4 The overcurrent protection element 10 shown is shaped such that the lateral width of the metal plate 14B, which serves as the second external connection portion 13B, is smaller than the lateral width of the rectangular printed circuit board 12, and the metal plate 14B does not protrude from either side of the printed circuit board 12. Although not shown, the overcurrent protection element can also be shaped such that the lateral width of the metal plate, which serves as the first external connection portion, is narrower than that of the printed circuit board, thus resulting in a more compact shape.

[0058] Furthermore, in Figures 3 to 7 In the overcurrent protection elements 10, 20, and 30, the insulating layer 15 is provided as an insulating plastic molded body 16 or 26 to insulate the surface of the printed circuit board 12. However, in the overcurrent protection elements 10, 20, and 30 of the present invention, the insulating layer 15 is not necessarily limited to the insulating plastic molded body 16 or 26. Although not shown, it can be provided, for example, as an insulating layer 15 or other insulating elements laminated on the surface of the printed circuit board 12 such as coating the surface of the printed circuit board 12 with potting resin to insulate the substrate surface.

[0059] Insulating plastic molded bodies 16 and 26 are molded into shapes almost identical to the rectangular printed circuit board 12, and are stacked on the surface of the printed circuit board 12 to insulate the surface of the printed circuit board 12. The insulating layers 15 of the insulating plastic molded bodies 16 and 26 are stacked and fixed to the surface of the printed circuit board 12 to reinforce the printed circuit board 12. The insulating plastic molded bodies 16 and 26 are fixed to the printed circuit board 12 by a snap-fit ​​structure, or by clamping the printed circuit board 12 from both sides, or by adhesive bonding.

[0060] like Figure 4As shown, the insulating plastic molded body 16, which is fixed to the printed circuit board 12 by a locking structure, has locking hooks 18 integrally formed on both sides. The locking hooks 18 have locking portions 18A on their inner sides that can lock the printed circuit board 12. The insulating plastic molded body 16 is fixed to the printed circuit board 12 by locking the lower surface of the printed circuit board 12 by the locking hooks 18.

[0061] in addition, Figure 8 An example of an insulating plastic molded body 36 fixed in a manner that clamps a printed circuit board 12 is shown. Figure 8 In the insulating plastic molded body 36, a back cover 36A disposed on the back side of the printed circuit board 12 is connected to an insulating cover 36B that insulates the surface via a bendable hinge portion 36C. The hinge portion 36C is molded thin to be bendable, and is integrally molded with the back cover 36A and the insulating cover 36B. Furthermore, the insulating plastic molded body 36 has a locking hook 18 at the front end of the insulating cover 36B. When the surface of the printed circuit board 12 is covered by the back cover 36A, the hinge portion 36C, and the insulating cover 36B, the locking hook 18 locks onto the back cover 36A, thereby fixing it to the printed circuit board 12.

[0062] Figure 3 , Figure 4 , Figure 7 as well as Figure 8 The insulating plastic molded bodies 16 and 36 shown are provided with openings 17 for guiding the surface-mounted chip fuses 11 and external connectors 13 onto the printed circuit board 12. In this shape of insulating plastic molded body 16 and 36, surface-mounted components protruding from the surface of the printed circuit board 12 can be guided into the interior of the opening 17, thus allowing for overall thinning of the surface of the printed circuit board 12 for insulation. The opening 17 is filled with an insulating element 21, that is, the surface of the chip fuses 11 and external connectors 13 disposed inside the opening 17 is insulated by covering them with the insulating element 21.

[0063] Furthermore, in Figure 3 , Figure 4 as well as Figure 7 In the overcurrent protection elements 10 and 30 shown, a retaining portion 19 for the external connection portion 13 is provided in the insulating plastic molded body 16. The retaining portion 19 consists of retaining protrusions 19A and 19B protruding toward the surface of the external connection portion 13. The retaining protrusions 19A and 19B clamp the metal plates 14A and 14B, which serve as the external connection portion 13, with the printed circuit board 12, holding them in a fixed position. The retaining portion 19 is integrally formed in the insulating plastic molded body 16, and the retaining portion 19 is located on the surface of the metal plates 14A and 14B to prevent the protrusions 14a of the metal plates 14A and 14B from peeling off from the printed circuit board 12.

[0064] Furthermore, in Figure 7 In the overcurrent protection element 30 shown, instead of using a metal plate for the second external connection portion 13B, a portion of the conductive portion 12B provided on the surface of the printed circuit board 12 is used as the second external connection portion 13B to directly solder the lead 4A of the voltage detection line 4. The retaining protrusion 19B, integrally formed on the insulating plastic molded body 16, functions as a retaining portion 19 to hold the lead 4A in a fixed position. This effectively prevents the lead 4A soldered to the conductive portion 12B from peeling off.

[0065] in addition, Figure 5 and Figure 6 The insulating plastic molded body 26 is configured as a box shape with an opening at the top, designed to house the printed circuit board 12. The insulating plastic molded body 26 has a peripheral wall 27 along the outer periphery of the printed circuit board, and this peripheral wall 27 is higher than the thickness of the printed circuit board 12. Furthermore, in Figure 6 In the insulating plastic molded body 26, the peripheral walls 27 at both ends are partially cut off to serve as positioning recesses 28 for guiding the metal plates 14C and 14D, which serve as external connecting parts 13. The insulating plastic molded body 26 in the figure uses the peripheral walls 27 on both sides of the positioning recesses 28 as fitting protrusions 29 to guide the fitting recesses 14c provided on both sides of the metal plates 14C and 14D. This insulating plastic molded body 26 fixes the internally housed printed circuit board 12 in a fixed position by a snap-fit ​​structure or by adhesive bonding, and connects the metal plates 14C and 14D, which serve as external connecting parts 13, to a fixed position by fitting the fitting protrusions 29 on both sides of the positioning recesses 28 into the fitting recesses 14c provided on both sides of the metal plates 14C and 14D. Therefore, the protrusions 14a of the metal plates 14C and 14D can be accurately positioned relative to the conductive portion 12B provided on the surface of the printed circuit board 12, and the protrusions 14a of the metal plates 14C and 14D can be stacked and brazed to the conductive portion 12B provided on the surface of the printed circuit board 12.

[0066] Furthermore, in Figure 5 and Figure 6 In the overcurrent protection element 20, the surface of the printed circuit board 12 housed in the insulating plastic molded body 26 and the inner side of the peripheral wall 27 are filled with an insulating element 21 such as potting resin to cover the chip fuse 11 disposed inside and the surface of the printed circuit board 12 to insulate them.

[0067] by Figure 9 Assembly of the process shown Figure 7 The overcurrent protection element shown is shown.

[0068] like Figure 9 As shown in (1), a conductive portion 12B is provided on the surface of an insulating substrate 12A to fabricate a printed circuit board 12.

[0069] like Figure 9 As shown in (2), the terminals at both ends of the chip fuse 11 are connected to a pair of conductive portions 12B by reflow soldering or the like, thereby mounting the chip fuse 11 onto the printed circuit board 12. In addition, a metal plate 14A serving as a first external connection portion 13A is soldered to one of the conductive portions 12B of the printed circuit board 12.

[0070] like Figure 9 As shown in (3), a fixed insulating plastic mold 16 is used to insulate the surface of the printed circuit board 12.

[0071] like Figure 9 As shown in (4), lead wire 4A is brazed onto the surface of the second external connection part 13B.

[0072] The above shows Figure 7 The assembly process of the overcurrent protection element 30 can be carried out by brazing or welding the metal plate of the second external connection part to assemble the overcurrent protection element.

[0073] In the above-described overcurrent protection elements 10, 20, and 30, the metal plate 14, serving as the external connection portion 13, is positioned on the outer side of the rectangular printed circuit board 12 along its long side, or the lead 4A connected to the second external connection portion 13B is led out along the long side of the printed circuit board 12. This configuration of the overcurrent protection elements 10, 20, and 30 results in an overall elongated shape, allowing them to be placed in confined spaces. However, for overcurrent protection elements, it is also possible to... Figure 10 As shown, the metal plate 14, which serves as the external connection part 13, and the lead wire 4A connected to the external connection part 13 are led out in the transverse direction, i.e. the short side direction, relative to the long side direction of the printed circuit board 12.

[0074] exist Figure 10 In the overcurrent protection element 40 shown, a metal plate 14E, serving as the first external connection portion 13A, is connected to the rectangular printed circuit board 12 in a manner that protrudes laterally relative to the rectangular printed circuit board 12. Furthermore, a lead 4A, connected to the second external connection portion 13B, is also arranged on the printed circuit board 12 in a manner that extends laterally relative to the printed circuit board 12. Therefore, an insulating plastic molded body 46, which insulates the surface of the printed circuit board 12, is provided with retaining protrusions 19A and 19B to hold the metal plate 14E and the lead 4A, which are laterally connected to the printed circuit board 12. When the arrangement of the overcurrent protection element is limited, such as when the external connection portion 13A and the lead 4A cannot be arranged in a straight line, the overcurrent protection element 40 with this configuration can be selectively used depending on the usage conditions.

[0075] Furthermore, in overcurrent protection components, such as Figure 11 and Figure 12 As shown, the insulating substrate 12C can be bent for use as a flexible insulating substrate. In the overcurrent protection element 50 of these figures, such as... Figure 11 As shown in (1), a protruding connecting portion 12c, which is part of an insulating substrate 12C, and a metal plate 14F, which is fixed to the protruding connecting portion 12c and serves as a first external connecting portion 13A, are provided in such a way that they protrude laterally along the rectangular printed circuit board 12. Additionally, a lead 4A connected to the second external connecting portion 13B extends along the long side of the printed circuit board 12. The illustrated insulating plastic molded body 56 is provided with a retaining recess 57 for positioning the lead 4A in a fixed position. In this overcurrent protection element 50, as... Figure 11 As shown in (2), the flexible insulating substrate 12C can be bent for use. In the overcurrent protection element 50 of this configuration, as Figure 12 As shown, the protruding connecting portion 12c of the insulating substrate 12C that protrudes laterally can be bent, thereby enabling the metal plate 14F, which serves as the first external connecting portion 13A, to be welded or brazed to the busbar 3 connected to the electrode terminal 2 of the battery cell 1.

[0076] In the above-mentioned overcurrent protection elements 10, 20, 30, 40, and 50, the first external connection part 13A is stacked and fixed to the busbar 3 of the battery system 100, and the second external connection part 13B is connected to the lead 4A of the voltage detection line 4 and positioned in the middle of the voltage detection line 4. In the battery system 100, the voltage of each battery is detected by connecting the voltage detection line 4 of the overcurrent protection elements 10, 20, 30, 40, and 50 in the middle, thereby protecting each battery cell 1 while the charging and discharging current is controlled by the control circuit 6, and safely charging and discharging the battery cell 1.

[0077] Industrial availability

[0078] The overcurrent protection element of the present invention is a protective element used in battery systems to protect batteries, and is preferably used as a protective element having a fuse that will blow due to excessive current. Furthermore, the battery system of the present invention is a battery system equipped with the overcurrent protection element, and is particularly preferably used as a power supply device for supplying power to the motor driving an electric vehicle, a power supply device for a server, a power storage device for storing electricity generated by solar panels, or a power storage device for storing electricity at night, etc., for high-power applications.

[0079] Explanation of reference numerals in the attached figures

[0080] 100: Battery system; 1: Battery cell; 2: Electrode terminal; 3: Busbar; 4: Voltage detection line; 4A: Lead; 5: Voltage detection circuit; 6: Control circuit; 7: Connection terminal; 10, 20, 30, 40, 50: Overcurrent protection element; 11: Chip fuse; 12: Printed circuit board; 12A, 12C: Insulating substrate; 12B: Conductive part; 12c: Protruding connection part; 13: External connection part; 13A: First external connection part; 13B: Second external connection part; 14, 14A, 14 B, 14C, 14D, 14E, 14F: Metal plate; 14a: Protrusion; 14b: Through hole; 14c: Fitting recess; 15: Insulating layer; 16, 26, 36, 46, 56: Insulating plastic molded body; 17: Open window; 18: Locking hook; 18A: Locking part; 19: Holding part; 19A, 19B: Holding protrusion; 21: Insulating part; 27: Peripheral wall; 28: Positioning recess; 29: Fitting protrusion; 36A: Back cover; 36B: Insulating cover; 36C: Hinge part; 57: Holding recess.

Claims

1. An overcurrent protection element, comprising: Chip fuse; A printed circuit board on which the chip fuse is mounted; External connection portion, which is connected to the printed circuit board; and An insulating layer is disposed on the printed circuit board. in, The printed circuit board has conductive portions on the surface of an insulating substrate. The external connection portion is electrically connected to the conductive portion of the printed circuit board. The chip fuse is electrically connected to the conductive part. The chip fuse is connected to the external connection part via the conductive part. The insulating layer is an insulating plastic molded body bonded to the surface of the printed circuit board. The insulating plastic molded body has an opening window that exposes the chip fuse. The opening window is covered by an insulating element. The insulating plastic molded body has a retaining portion for the external connection portion. The retaining portion includes a retaining protrusion that protrudes toward the surface of the external connection portion.

2. The overcurrent protection element according to claim 1, characterized in that, The insulating substrate is a planar rigid substrate.

3. The overcurrent protection element according to claim 1, characterized in that, The insulating substrate is a flexible substrate with flexibility.

4. The overcurrent protection element according to any one of claims 1 to 3, characterized in that, The external connection part is composed of a first external connection part and a second external connection part as a pair, and the first external connection part is a metal plate.

5. The overcurrent protection element according to claim 4, characterized in that, The metal plate is plate-shaped and connected to the busbar. The busbar is fixed to the electrode terminals of each battery constituting the battery system, which is formed by connecting multiple batteries in series.

6. The overcurrent protection element according to claim 4, characterized in that, The second external connection part is either a metal plate or a lead wire soldered to the conductive part of the printed circuit board.

7. The overcurrent protection element according to claim 4, characterized in that, The second external connection part is a metal plate soldered to the conductive part of the printed circuit board and a lead wire connected to the metal plate.

8. The overcurrent protection element according to claim 1, characterized in that, The insulating plastic molded body is connected to the printed circuit board via a locking structure.

9. The overcurrent protection element according to claim 1, characterized in that, The insulating plastic molded body is fixed in such a way that it clamps two sides of the printed circuit board.

10. The overcurrent protection element according to any one of claims 1 to 3, characterized in that, The external connection part is a connection part that is connected to the voltage detection line. The voltage detection line detects the voltage of each battery that makes up the battery system. The battery system is formed by connecting multiple batteries in series.

11. A battery system comprising: Multiple battery cells; A busbar, which is a metal plate fixed to the electrode terminals of the battery cells to connect the battery cells; and A voltage detection circuit is connected to the busbar via a voltage detection line equipped with an overcurrent protection element. in, The overcurrent protection element includes: Chip fuse; A printed circuit board on which the chip fuse is mounted; External connection portion, which is connected to the printed circuit board; and An insulating layer is disposed on the printed circuit board. The printed circuit board has conductive portions on the surface of an insulating substrate. The external connection portion is electrically connected to the conductive portion of the printed circuit board. The chip fuse is electrically connected to the conductive part. The chip fuse is connected to the external connection part via the conductive part. The external connection part is connected to the voltage detection line. The insulating layer is an insulating plastic molded body bonded to the surface of the printed circuit board. The insulating plastic molded body has an opening window that exposes the chip fuse. The opening window is covered by an insulating element. The insulating plastic molded body has a retaining portion for the external connection portion. The retaining portion includes a retaining protrusion that protrudes toward the surface of the external connection portion.

12. The battery system according to claim 11, characterized in that, The insulating substrate is either a planar rigid substrate or a flexible substrate.

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