TWI728168B - Productive element, circuit module and method of producing protective element - Google Patents

Abstract

Provided is a protective element with a space inside a covering part and a circuit module incorporating the protective element, which can prevent the expansion of the internal air from reducing the adhesion strength of the covering member to prevent damage to electronic parts and prevent sealing resin Or the inflow of washing liquid, etc.

It has an insulating substrate 10, first and second electrodes 11, 12 provided on the insulating substrate 10, a soluble conductor 13 arranged across the first and second electrodes 11, 12, and a configuration that can be arranged on the insulating substrate 10. The covering member 20 on the side of one surface 10a of the fused conductor 13 is provided with a vent hole 23 where the internal space 25 in which the soluble conductor 13 is arranged faces the outside of the element, and the vent hole 23 is sealed by a sealing member 24.

Description

Protective element, circuit module and manufacturing method of protective element

The present invention relates to a protective element that cuts off a power line or a signal line, and a circuit module in which the protective element is built on a circuit substrate.

Most secondary batteries that can be used repeatedly after charging are provided to users after processing into battery packs. Especially for lithium-ion secondary batteries with high weight and energy density, in order to ensure the safety of users and electronic equipment, in general, several protection circuits such as overcharge protection and overdischarge protection are built in the battery pack, which can be used in established situations. The function of blocking the output of the battery pack.

Among such protection components, there is a FET (Field Effect Transistor) switch built in the battery pack to turn on/off the output, thereby performing overcharge protection or overdischarge protection of the battery pack. However, even if the FET switch is damaged by a short circuit or a lightning surge is applied for some reason, a large current flows instantaneously, or the output voltage is abnormally lowered due to the life of the battery cell, or the output is excessively large. , Or when the voltage difference between the batteries is too large, the battery pack or electronic equipment must be protected to avoid accidents such as fire. Therefore, in order to safely interrupt the output of the battery under all these predictable abnormal conditions, a fuse with the function of interrupting the current path with a signal from the outside is used. Protective components composed of components.

As the interrupting element used in the protection circuit of the lithium ion secondary battery, as shown in Figure 17 (A), (B), there is a first electrode 91, a heating element lead electrode 95, and a second electrode on the current path. A soluble conductor 93 is connected between the electrodes 92 to form a part of the current path. The soluble conductor 93 on the current path generates heat by itself through overcurrent, or energizes the heating element 91 provided inside the protection element to fuse it者 (refer to Patent Document 1). In such a protective element 90, the first and second electrodes 91 and 92 are separated by collecting the molten liquid soluble conductor 93 on the heating element extraction electrode 95 connected to the heating element 94 and the first and second electrodes 91 and 92. The current path is blocked between the second electrodes 91 and 92.

The protective element, the fusible conductor 93 is fused due to the heating of the heating element 94, and the fusible conductor 93 is fused due to the self-heating generated by the overcurrent. Therefore, in order to prevent the fused soluble conductor 93 from flying off, it is a part of the external parts. The covering member 97 is sealed. In addition, the protective element 90, in order to stably realize the fusing effect of the soluble conductor 93 caused by the heating element 94, the cover member 97 is provided with an internal space for the soluble conductor 93 to melt and flow. Furthermore, as shown in FIG. 18, the covering member 97 is provided with a vent 99 in the covering member 97 in order to release the explosive energy when the current is interrupted to the outside and prevent damage to the element.

In addition, the protective element 90 is coated with a flux 98 that removes the oxide film on the surface of the soluble conductor 93 in order to prevent oxidation of the surface of the soluble conductor 93 and maintain rapid fusing.

Advanced technical literature

[Patent Document 1] JP 2010-003665 A

[Patent Document 2] JP 2001-076610 A

The protection element 90 can be constructed on a circuit board on which a power supply circuit or the like is formed to form a part of the charging and discharging path, and the charging and discharging path can be blocked by the fusing of the soluble conductor 93.

Here, the circuit board on which the protective element 90 is constructed is coated with resin in order to improve the strength and smoothness of the substrate, and the protective element 90 may also be sealed by the resin. Alternatively, the circuit board may be subjected to post-processing such as board cleaning for the purpose of removing the flux or solder balls scattered on the printed board.

However, since the protective element 90 is provided with a vent hole 99 in the covering member 97, the sealing resin or cleaning liquid will penetrate into the inside from the vent hole 99, and the internal space for the soluble conductor 93 to melt and flow is buried. Or the problem that the soldering flux 98 is removed, etc., has caused damage as a protective element, and should have a proper blocking function.

Although the sealed protective element without vent holes on the covering member is also widely circulated, as an adhesive for adhering to the covering member, when a thermosetting adhesive with strong bonding strength is used, the air inside the element will expand during heating. Air leaks out between the unhardened liquid adhesives and cannot be sealed by the covering member. In addition, the adhesive strength of the covering member is reduced. Moreover, when reflow soldering a sealed protective component on a circuit board, the air inside the component will also expand, and the internal pressure of the component will increase due to the vaporization of the flux contained in the flux, and the internal pressure of the component will increase due to reflow. Welding heating causes the adhesive to soften. Similarly, it cannot be sealed with the covering member, and the adhesive strength of the covering member is also reduced. Furthermore, in a sealed protection element, the explosive energy generated when the fusible conductor is interrupted cannot be released to the outside of the element, and some elements are damaged. Danger.

In addition, after the assembly of an open-type protection element in which the cover member is provided with vent holes, a method of sealing the protection element with resin to prevent the sealing material of the circuit board or the cleaning solution from intruding (refer to FIG. 19) can also be considered. However, in order to reliably perform sealing, resin must be applied to the entire protective element and its periphery, and a large amount of sealing resin is required. In addition, as shown in FIG. 20, when other parts are built around the protective element, coating becomes difficult. Furthermore, as shown in FIG. 21, since one piece of the circuit board needs to be coated, the productivity of the circuit board is low.

This technology was developed to solve the above-mentioned problems, and its purpose is to provide a protective element with a space inside the covering member and a circuit module equipped with the protective element, which can prevent the adhesive strength of the covering member caused by the expansion of the internal air Lowering to prevent damage to electronic parts, and to prevent the inflow of sealing resin or cleaning liquid, etc., and the circuit module with the protection element, and the manufacturing method of the protection element.

In order to solve the above-mentioned problems, the protection element of the present technology includes: an insulating substrate; first and second electrodes arranged on the insulating substrate; a soluble conductor arranged across the first and second electrodes; and a covering member , Is arranged on the side of the insulating substrate where the soluble conductor is arranged; is provided with a vent hole where the inner space where the soluble conductor is arranged faces the outside of the element; the vent hole is sealed by a sealing member.

In addition, the circuit module of the present technology has a protection element and a circuit substrate with the protection element mounted on the surface; the protection element includes: an insulating substrate; the first and second electrodes are provided on the insulating substrate; The fused conductor is arranged across the first and second electrodes; and the covering member is arranged on the side of the insulating substrate where the soluble conductor is arranged; The inner space of the fused conductor faces the vent hole outside the element; the vent hole is sealed by the sealing member.

In addition, the manufacturing method of the protective element of the present technology, the manufacturing method of the protective element, is to form the first and second electrodes on an insulating substrate, and arrange a soluble conductor across the first and second electrodes; on the insulating substrate The covering member is mounted on the thermosetting resin to form a structure with a vent hole where the inner space where the soluble conductor is arranged faces the outside of the element; the covering member is connected to the insulating substrate by heating the structure; The vent hole is sealed with a sealing member.

According to the present technology, it is possible to release to the outside the expansion gas equal to that generated in the internal space when the covering member is connected. In addition, since the vent hole is sealed by the sealing member after the covering member is connected, it is possible to prevent the sealing resin applied on the circuit board or the cleaning liquid of the circuit board from entering the inside of the device from the vent hole, and maintain a proper blocking function as a protective device. Furthermore, in the protection element, since the vent hole is sealed by the sealing member, the connection strength between the cover member and the insulating substrate can be improved. When the air expands and the internal pressure becomes high, the covering member can also be prevented from peeling off or being damaged from the insulating substrate.

1: protection element

2: Circuit board

3: Circuit module

10: Insulating substrate

10a: The surface of the insulating substrate

10f: The back of the insulating substrate

11: 1st electrode

11a: External connection electrode

12: 2nd electrode

12a: External connection electrode

13: Fusible conductor

14: heating element

15: Insulating member

16: The heating element leads the electrode

17: Flux

18: The first heating element electrode

19: The second heating element electrode

20: cover member

21: side

22: top surface

23: Vent

24: Sealing member

24a: Thermosetting resin

24b: Mating pin

25: Internal space

26: Adhesive

27: next wall

28: Structure

31: protrusion

32: Taper

33: Partition wall components

33a: Side of the partition wall

33b: The top surface of the partition wall

35: Protection element

36: Intermediate substrate

37: Protection component package

38: cover member

39: Locking section

40: Protection element

41: cover member

42: side

42a: Locking piece

43: top surface

50: battery pack

51~54: battery

55: battery stack

56: detection circuit

57: Current control element

60: charge and discharge control circuit

61: Current control element

62: Current control element

63: Control Department

65: charging device

Fig. 1 is a perspective view showing the appearance of a protective element to which this technology is applied.

Figure 2 shows a cross-sectional view of a circuit module to which this technology is applied.

Fig. 3 is a top view on the surface of the insulating substrate showing the protective element with the covering member omitted.

Fig. 4 is a perspective view showing the appearance of a protective element to which this technology is applied from the back side.

Figure 5 is a cross-sectional view showing the manufacturing process of the protective device applying this technology, (A) is the insulating base The state in which various electrodes, heating elements, and soluble conductors are arranged on the board, (B) is a state in which a covering member is mounted, and (C) shows a state in which a sealing member has been supplied to the vent hole.

Fig. 6 is a diagram showing a protective element provided with a protrusion on the partition wall, (A) is a perspective view of the appearance, and (B) is a cross-sectional view.

Fig. 7 is a diagram showing a protective element with a second protruding portion protruding to the side of the insulating substrate outside of the partition wall provided with a protruding portion, (A) is an external perspective view, and (B) is a cross-sectional view.

Fig. 8 is a diagram showing a protective element provided with a tapered portion on the partition wall, (A) is a perspective view of the appearance, and (B) is a cross-sectional view.

Fig. 9 is a diagram showing a protective element in which a partition wall member is arranged, (A) is an appearance perspective view, and (B) is a cross-sectional view.

FIG. 10 is a diagram showing a protective device package of a reference example, (A) is a perspective view of the appearance, and (B) is a cross-sectional view.

11 is a diagram showing a protective element filled with a thermosetting resin on the top surface of the partition wall member using a cover member without a top surface, (A) is an appearance perspective view, and (B) is a cross-sectional view.

Fig. 12 is a diagram showing a protective element in which a thermosetting resin and a fitting pin are arranged in a vent hole to seal, and (A) is an external perspective view, and (B) is a cross-sectional view.

Fig. 13 is a diagram showing a protective element connecting a fitting pin inserted into a vent hole to an insulating substrate, (A) is an external perspective view, and (B) is a cross-sectional view.

14 is a diagram showing a protection element of a reference example in which a locking piece provided on a covering member is locked on an insulating substrate, (A) is an external perspective view, (B) is a cross-sectional view, and (C) is a bottom view.

Fig. 15 is a circuit diagram showing an example of a battery pack to which a protective element is applied.

Figure 16 is a circuit diagram of the protection element.

FIG. 17 is a diagram showing the conventional protection element, (A) is a plan view showing the cover member omitted, and (B) is a cross-sectional view.

Fig. 18 is a perspective view showing the appearance of the previous protection element.

Fig. 19 is a perspective view showing the external appearance of the step of sealing the protective element with resin after the assembly of the open-type protective element.

Fig. 20 is a perspective view showing the appearance of interference with other parts of the surrounding structure of the protective element.

FIG. 21 is a perspective view showing the appearance of the step of applying a sealing resin to each piece of the circuit board.

Hereinafter, the manufacturing method of the protection element, the circuit module and the protection element to which this technology is applied will be described in detail while referring to the drawings. In addition, the present technology is not limited to the following embodiments, and of course various changes are possible without departing from the gist of the present technology. In addition, the drawing is shown schematically, and the ratio of each size may be different from the actual product. The specific dimensions should be judged with reference to the following description. Moreover, it is of course possible that the various drawings may include parts with different dimensional relationships or ratios.

As shown in FIG. 1 and FIG. 2, the circuit module 3 to which the present invention is applied has a protective element 1 on the surface of the circuit substrate 2. The circuit board 2 is formed with, for example, a protection circuit of a lithium ion secondary battery. The protective element 1 is mounted on the surface, and a soluble conductor 13 is assembled on the charging and discharging path of the lithium ion secondary battery. In the circuit module 3, when a large current exceeding the rating of the protection element 1 flows, the current path is blocked by the fusible conductor 13 due to self-heating (Joule heat). In addition, the circuit module 3 can energize the heating element 14 at a predetermined timing by a current control element provided on the circuit board 2 and so on, so that the heat of the heating element 14 causes the soluble conductor 13 to fuse to block the current path. .

In addition, FIG. 1 is a perspective view showing the appearance of a protective element 1 to which the present invention is applied. 2 is a cross-sectional view showing a part of the circuit module 3 of the protective element 1 mounted on the circuit substrate 2, FIG. 3 is a plan view showing the surface 10a of the insulating substrate 10 of the protective element 1 without the cover member 20, and FIG. 4 shows the protection A perspective view of the appearance of the back side of the element 1.

〔Protection component〕

The protective element 1, as shown in FIGS. 2 to 5, includes an insulating substrate 10, a heating element 14 laminated on the insulating substrate 10 and covered by an insulating member 15, and a first electrode 11 and a second electrode formed on both ends of the insulating substrate 10 12. The heating element lead electrode 16 laminated on the insulating member 15 so as to overlap the heating element 14, and the two ends are connected to the first and second electrodes 11, 12, and the central part is connected to the heating element lead electrode 16. Fuse conductor 13.

The insulating substrate 10 is formed into an approximately square shape using an insulating member such as alumina, glass ceramics, mullite, and zirconia. In addition to the insulating substrate 10, materials used for printed wiring substrates such as glass epoxy substrates and phenol substrates can also be used.

[First and second electrodes]

The second electrodes 11 and 12 are separately arranged and opened on the surface 10a of the insulating substrate 10 near the opposite side edges, and are electrically connected through the soluble conductor 13 by mounting the soluble conductor 13 described later. In addition, the first and second electrodes 11, 12, when a large current exceeding the rated current flows through the protection element 1, the soluble conductor 13 is fused due to self-heating (Joule heat), or the heating element 14 generates heat due to energization, making the soluble conductor 13 fused, but blocked.

As shown in FIG. 2, the first and second electrodes 11, 12 respectively pass through the castellation provided on the first and second side surfaces 10b, 10c of the insulating substrate 10 and the external connection electrode 11a provided on the back surface 10f. , 12a connection. The protection element 1 is connected to the circuit board 2 on which the external circuit is formed through these external connection electrodes 11a, 12a, and is configured as a energizing path of the external circuit Part.

The first and second electrodes 11 and 12 can be formed using general electrode materials such as Cu or Ag. Also, the surfaces of the first and second electrodes 11, 12 are preferably coated with Ni/Au plating, Ni/Pd plating, Ni/Pd/Au plating, etc. by a known technique such as plating treatment. The film is better. In this way, in the protection element 1, the oxidation of the first and second electrodes 11, 12 can be prevented, and the rated fluctuation accompanying the increase in the on-resistance can be prevented. In addition, when the protective element 1 is reflowed and assembled, the solder for connecting the soluble conductor 13 or the melting of the low-melting point metal forming the outer layer of the soluble conductor 13 can prevent the first and the second from erosion. 2 Electrodes 11, 12.

〔heating stuff〕

The heating element 14 is a member that generates heat when it is energized, and has conductivity, and is made of, for example, W, Mo, Ru, Cu, Ag, or alloys with the main components thereof. The heating element 14 can be formed by mixing the alloy or composition, powder of the compound with a resin binder, etc., and then forming a paste on the insulating substrate 10 using screen printing technology to form a pattern, by firing Formed by waiting. In addition, one end of the heating element 14 is connected to the first heating element electrode 18 and the other end is connected to the second heating element electrode 19.

The protective element 1 is provided with an insulating member 15 so as to cover the heating element 14, and a heating element lead electrode 16 is formed through the insulating member 15 to face the heating element 14. In order to efficiently transfer the heat of the heating element 14 to the soluble conductor 13, an insulator may be laminated between the heating element 14 and the insulating substrate 10. As the insulating member 15, for example, a glass material can be used.

One end of the heating element lead electrode 16 is connected to the first heating element electrode 18 and is continuous with one end of the heating element 14 through the first heating element electrode 18. In addition, the first heating body electrode 18 is formed on the third side surface 10 d side of the insulating substrate 10, and the second heating body electrode 19 is formed on the fourth side surface 10 e side of the insulating substrate 10. In addition, the second heating element electrode 19 is formed on the fourth side surface 10e through The castle-shaped contact is connected to the external connection electrode 19a formed on the back surface 10f of the insulating substrate 10.

The heating element 14 is mounted on the circuit board 2 by the protection element 1, and is connected to an external circuit formed on the circuit board 2 through the external connection electrode 19 a and the second heating element electrode 19. In addition, the heating element 14 can be energized and heated through the external connection electrode 19a and the second heating element electrode 19 at a predetermined timing of blocking the energization path of the external circuit, and the first and second electrodes 11, 12 are connected by fusing. Fusible conductor 13. In addition, since the heating element 14 is fused and the current path of the soluble conductor 13 is also interrupted, the heating element 14 stops heating.

〔Fusible Conductor〕

The soluble conductor 13 is made of a material that can be quickly fused due to the heat generated by the heating element 14. For example, it is very suitable to use low-melting-point metals such as solder or lead-free solder with Sn as the main component.

In addition, the soluble conductor 13 may use a high melting point metal such as In, Pb, Ag, Cu, or an alloy containing any one of these as the main component, or may have a low melting point metal layer as an inner layer and a high melting point metal layer. The melting point metal layer is a laminate of low melting point metal and high melting point metal such as the outer layer. With the inclusion of high-melting-point metals and low-melting-point metals, when reflowing the protective element 1, even if the reflow temperature exceeds the melting temperature of the low-melting-point metal and the low-melting-point metal is melted, the outflow of the low-melting-point metal to the outside can be suppressed and maintained The shape of the soluble conductor 13. In addition, at the time of fusing, the high melting point metal is eroded (solder erosion) due to the melting of the low melting point metal, and the high melting point metal can be quickly melted at a temperature below the melting point of the high melting point metal.

In addition, the soluble conductor 13 is connected to the heating element extraction electrode 16 and the first and second surface electrodes 11 and 12 through solder or the like. The soluble conductor 13 can be easily connected by welding. .

In addition, the soluble conductor 13 is preferably coated with a flux 17 in order to prevent oxidation, improve wettability, and the like.

〔Cover member〕

In addition, the protective element 1 is provided with a covering member 20 on the surface 10a of the insulating substrate 10 to protect the inside. The covering member 20 is formed into a substantially rectangular shape in accordance with the shape of the insulating substrate 10. In addition, as shown in FIG. 1, the covering member 20 has a side surface 21 connected to the surface 10a of the insulating substrate 10 on which the soluble conductor 13 is arranged, and a top surface 22 covering the surface 10a of the insulating substrate 10, on the insulating substrate 10. On the surface 10a, there is a sufficient internal space 25 for the soluble conductor 13 to expand into a spherical shape when it is melted, and the fused conductor to condense on the heating element extraction electrode 16 and the first and second electrodes 11, 12.

The side surface 21 of the covering member 20 is connected to the surface 10a of the insulating substrate 10 through the adhesive 26 or the like. As the adhesive 26 for connecting the covering member 20, a thermosetting adhesive with excellent connection reliability is very suitable.

〔Vent holes〕

In addition, as shown in FIGS. 1 and 2, the covering member 20 is provided with a vent hole 23 penetrating the inside of the covering member 20, and the inside of the vent hole 23 is sealed by a sealing member 24. The vent hole 23 is, for example, opened on the top surface 22 of the covering member 20. In addition, the vent hole 23 is constituted by the side surface 21 of the covering member 20 and the partition wall 27 separating the internal space 25 in which the soluble conductor 13 is arranged. The partition wall 27 is formed downward from the top surface 22 of the covering member 20, and is formed to have a height of a few gaps between the covering member 20 and the surface 10a of the insulating substrate 10 when the covering member 20 is connected to the surface 10a of the insulating substrate 10. That is, the vent hole 23 is continuous with the internal space 25 through the gap between the partition wall 27 and the insulating substrate 10, and can release the expansion gas generated in the internal space 25 when the covering member 20 is connected to the outside. The vent hole 23 is sealed by the sealing member 24 after the covering member 20 is connected. The manufacturing process of this protection element 1 will be described in detail later.

By providing the vent hole 23 and sealing the vent hole 23 with the sealing member 24, the protective element 1 can prevent the sealing resin applied to the circuit board 2 and the cleaning liquid of the circuit board 2 from intruding into the device from the vent hole 23 , Resulting in accidents that the internal space for melting and flowing of the soluble conductor 13 is buried, or the flux 17 is removed, etc., and maintains a proper blocking function as a protective element. In addition, in the protection element 1, the vent hole 23 is sealed by the sealing member 24, so that the connection strength between the cover member 20 and the insulating substrate 10 can be improved. When reflowing the circuit substrate 2 and the soluble conductor 13 When the air inside the element expands during fusing to increase the internal pressure, it is also possible to prevent peeling and damage of the covering member 20 from the insulating substrate 10.

The vent hole 23 is formed inside the element at a position that does not interfere with the heating element 14 and the soluble conductor 13, for example, as shown in FIG. 2, above the first and second electrodes 11 and 12, along the first and second electrodes Two side surfaces 10b and 10c are formed. Except as shown in FIG. 2, the vent hole 23 may be formed above the first and second heating element electrodes 18, 19, or continuously on any of the first to fourth side surfaces 10b, 10c, 10d, and 10e. Alternatively, the vent hole 23 may be formed on the side surface 21 of the covering member 20, or may be formed to penetrate from the surface 10a of the insulating substrate 10 to the back surface 10f. Furthermore, in the protection element 1, the vent holes 23 can also be formed at one or more of the top surface 22, the side surface 21, and the insulating substrate 10. Hereinafter, a case where the vent hole 23 is formed on the top surface 22 of the covering member 20 is taken as an example, and the description is continued.

〔Sealing member〕

The sealing member 24 for sealing the vent hole 23, for example, a thermosetting resin 24a is very suitable. As a specific example of the thermosetting resin 24a, for example, a thermosetting resin (e.g., SX720B manufactured by Cemedine) can be used. In addition, for the thermosetting resin 24a, a sealing sheet (manufactured by Kyocera Chemical Co., Ltd.: TMS-701) or the like may also be used. In addition, as the resin material, for example, a polyamide resin adhesive (manufactured by Henkel Corporation: OM678) can be used. Thermosetting resin 24a, as long as it is The vent hole 23 of the covering member 20 can be sealed to prevent the resin material and cleaning liquid used in the assembly step described later from flowing into the internal space 25, and the internal pressure may increase due to the expansion of the gas inside the element At this time, if the viscosity or strength of the connection with the insulating substrate 10 of the covering member 20 can be maintained, it can be in a liquid form, a sheet form, or the like.

The thermosetting adhesive 24a is supplied and filled into the vent hole 23 after the cover member 20 is attached to the insulating substrate 10, and is heated to a predetermined temperature during reflow assembly, etc., to be cured.

Here, the glass transition point of the thermosetting resin 24a is preferably lower than the reflow temperature when the protective element 1 is reflowed and assembled on the circuit board 2. In this way, the thermosetting resin 24a of the protective element 1 is hardened first in the assembling step of the circuit board 2. Therefore, when the gas in the internal space 25 expands and the internal pressure rises, it can prevent the cover member 20 from falling off the insulating substrate 10 The accidental detachment of the surface 10a.

In addition, the glass transition point of the thermosetting resin 24a is preferably 100°C or higher. In this way, during the reflow soldering step, it can be surely hardened to seal the vent hole 23, and the connection strength of the covering member 20 to the insulating substrate 10 can be improved.

Moreover, although the case where the thermosetting resin 24a is used as the sealing member 24 was demonstrated as an example, this technique is not limited to this, For example, a photocurable resin, such as an ultraviolet curable adhesive agent, may be used. The photocurable adhesive is supplied and filled into the vent hole 23 after the cover member 20 is attached to the insulating substrate 10, and cured by irradiating light with a predetermined wavelength such as ultraviolet light.

〔Process〕

Next, while referring to FIG. 5, the manufacturing process of the protection element 1 will be described. As shown in Figure 5(A), First, the first and second electrodes 11 and 12, the heating element 14, the first and second heating element electrodes 18 and 19, the insulating member 15 and the heating element extraction electrode 16 are formed on the surface 10a of the insulating substrate 10. In addition, external connection electrodes 11a, 12a, and 19a are formed on the back surface 10f of the insulating substrate 10, and are connected to the first, second electrodes 11, 12, and the second heating body electrode 19 through castellated contacts. Next, the soluble conductor 13 is mounted across the first and second electrodes 11 and 12 through the heating element lead electrode 16. In addition, between the soluble conductor 13 and the first and second electrodes 11 and 12 and the heating element extraction electrode 16, solder for connection can be supplied.

Next, as shown in FIG. 5(B), the covering member 20 is connected to the surface 10a of the insulating substrate 10. The connection of the covering member 20 is preferably performed by supplying a thermosetting adhesive 26 with excellent connection strength to the lower part of the side surface 21. The structure 28 in which the covering member 20 is mounted on the surface 10 a of the insulating substrate 10 can ensure the internal space 25 defined by the partition wall 27 around the soluble conductor 13.

Next, the structure 28 with the covering member 20 mounted on the surface 10a of the insulating substrate 10 is heated, and the soluble conductor 13 is connected to the first and second electrodes 11 and 12 and the heating element extraction electrode 16 through the solder for connection. After the thermosetting adhesive 26 is cured, the covering member 20 is connected to the surface 10a of the insulating substrate 10.

At this time, the expansion gas in the internal space 25 is discharged to the outside through the vent hole 23 provided in the covering member 20, so the internal pressure of the covering member 20 will not increase during the curing of the adhesive 26. The connection to the surface 10a of the insulating substrate 10 is not hindered.

Next, as shown in FIG. 5(C), the sealing member 24 is supplied to the vent hole 23, and the protective element 1 is formed after being sealed. The protective element 1 is assembled by reflow soldering to form a power source Circuit boards 2 such as circuits form circuit modules 3.

When the thermosetting resin 24a is used as the sealing member 24, the protective element 1 can be heat-treated to harden the thermosetting resin 24a, but it can also be used when reflowing the circuit board 2 It is heated to harden the thermosetting resin 24a. At this time, as the thermosetting resin 24a, a thermosetting resin 24a whose glass transition point is lower than the reflow temperature is used. The thermosetting resin 24a hardens first. Therefore, the connection strength of the covering member 20 is improved, even if it is due to the internal space. When the gas in 25 expands to increase the internal pressure, it can also prevent accidental separation of the covering member 20 from the surface 10a of the insulating substrate 10.

Furthermore, when a photocurable resin is used as the sealing member 24, it is preferable to irradiate ultraviolet light to harden it after filling the vent hole 23 and before reflowing the package to the circuit board 2.

[Modification 1]

Next, a modification example of the present technology will be described. In addition, in the description of each modification below, the same components as the above-mentioned protection element 1 and the circuit module 3 are given the same reference numerals, and detailed descriptions thereof are omitted.

As shown in Fig. 6, the vent hole 23 may be provided with a protrusion 31 protruding into the vent hole on the inner side. In the protection element 1, by providing the protrusion 31 on the inner surface of the vent hole 23 and filling the thermo-light-curable resin 24a or the photo-curable resin as the sealing member 24, the contact area in the vent hole 23 can be increased, and the contact area in the vent hole 23 can be increased. To improve the connection strength of the covering member 20.

As shown in FIG. 6, the protrusion 31 may be formed on the partition wall 27, the side surface 21, or both the partition wall 27 and the side surface 21. In addition, one or more protrusions 31 may be formed along the ventilation direction toward the top surface 22, and each of the plurality of protrusions 31 may have the same protrusion height or different protrusion heights. In addition, the protrusion 31 can be The cover member 20 is formed continuously or intermittently in the circumferential direction.

As shown in FIG. 6, when the vent hole 23 is provided on the top surface 22, the protruding portion 31 protrudes from the surface 10a of the insulating substrate 10, so the thermosetting resin 24a or the light-curing resin 24a or the light-curing resin in the vent hole 23 is filled The flexible resin can act as an anchor to the protruding portion 31 and make the covering member 20 less likely to be detached from the insulating substrate 10.

In addition, as shown in FIG. 7, the vent hole 23 can also be provided from the top surface 22 to the insulating substrate 10, and a protrusion 31 protruding into the vent hole 23 can be provided, and then the protrusion 31 is formed to protrude to the side of the insulating substrate 10 The second protrusion 31a. By protruding the second protrusion 31a toward the insulating substrate 10 side, the connection strength of the covering member 20 to the direction parallel to the insulating substrate 10 can be improved. That is, by protruding the protrusion 31 on the surface 10a of the insulating substrate 10 to increase the strength of the covering member 20 in the direction perpendicular to the insulating substrate 10, in contrast to this, the second protruding toward the surface 10a of the insulating substrate 10 The protrusion 31a is used to increase the strength of the covering member 20 in a direction parallel to the insulating substrate 10.

In addition, the second protrusion 31a may be one or plural, and each of the plural second protrusions 31a may protrude at the same height, or may protrude at different heights. In addition, the second protrusion 31a may be continuously formed in the entire circumferential direction of the covering member 20, or may be formed intermittently. In the covering member 20, the more the second protrusion 31a is formed, the more the strength against the direction parallel to the insulating substrate 10 increases.

In addition, the protruding portion 31 also includes a recessed portion formed on the inner surface of the partition wall 27 or the side surface 21, and the inner surface of the partition wall 27 or the side surface 21 protrudes from the recessed portion. In addition, the protrusion 31 also includes a form formed by so-called surface texturing, roughening processing, emboss processing, and the like.

Similarly, the second protruding portion 31a also includes a recessed portion formed in the protruding portion 31 facing the insulating substrate 10, and the protruding portion 31 protrudes to the side of the insulating substrate 10 oppositely. In addition, the second protrusion 31a also includes a form formed by so-called surface texturing, roughening, embossing, and the like.

[Modification 2]

As shown in FIG. 8, the inner surface of the vent hole 23 may be a tapered portion 32 formed in a tapered shape in the full venting direction when viewed in cross section. The protective element 1 has a tapered portion 32 formed on the inner side surface of the vent hole 23. When the thermo-light-curable resin 24a or photo-curable resin is filled as the sealing member 24, the contact area in the vent hole 23 can be increased. The connection strength of the covering member 20 is further improved.

The tapered portion 32 may be formed on the partition wall 27, or on the side surface 21, or on both the partition wall 27 and the side surface 21 as shown in FIG. In addition, although the tapered portion 32 may have a form in which the diameter is gradually expanded along the ventilation direction toward the top surface 22, or may be a form in which the diameter is tapered, as shown in FIG. The surface 22 has a form in which the diameter in the ventilation direction is gradually expanded. The thermosetting resin 24a or the light-curing resin filled in the ventilation hole 23 can act as an anchor to the tapered portion 32, making the covering member 20 more difficult to be insulated from The substrate 10 is detached, so it is preferable.

In addition, the above-mentioned protruding portion 31 or the second protruding portion 31 a may be formed in the tapered portion 32. In addition, the tapered portion 32 also includes a form in which the diameter is gradually expanded or reduced along the ventilation direction by being formed in a curved or stepped shape.

[Modification 3]

In addition, the protective element 1, as shown in FIG. 9, may also be arranged inside the covering member 20 to form a partition wall member 33 forming an internal space 25, between the top surface 22 of the covering member 20 and the partition wall member 33 The space is filled with thermosetting resin 24a or photocuring resin.

The partition wall member 33 is formed into a roughly box-like shape with one open side similar to the cover member 20, and has a partition wall side surface 33a constituting the vent hole 23 and a partition wall top surface 33b facing the top surface 22 of the cover member 20. And by disposing the partition wall member 33 on the surface 10a of the insulating substrate 10, the internal space 25 is formed accordingly. The partition wall member 33 has a gap formed between the lower part of the partition wall side surface 33 a facing the vent hole 23 and the surface 10 a of the insulating substrate 10, and the internal space 25 and the vent hole 23 are continuous. In addition, the partition wall member 33 is fixed by adhering the partition wall side surface 33 a that does not face the vent hole 23 to the surface 10 a of the insulating substrate 10.

In the protection element 1, the partition wall member 33 is provided to ensure the internal space 25 in which the soluble conductor 13 melts and flows, and the covering member 20 is further arranged on the partition wall member 33. Accordingly, the vent hole 23 is formed between the partition wall member 33 and the sealing member 24 such as thermosetting resin 24a is filled, so that the connection strength of the cover member 20 and the partition wall member 33 to the insulating substrate 10 can be improved. In addition, by filling the sealing resin between the top surface 34b of the partition wall and the top surface 22 of the covering member 20, the filling amount can be increased, and the connection strength of the covering member 20 and the partition wall member 33 to the insulating substrate 10 can be further improved.

In addition, the partition wall member 33 may be another member different from the covering member 20, or may be integrally molded with the covering member 20.

[Reference example 1]

Next, the structure of the protection element package 37 of the reference example of the present technology will be described with reference to FIG. 10. The protective element 35 shown in FIG. 10 has only the partition wall member 33 mounted on the surface 10 a of the insulating substrate 10. The protective element 35 is further assembled on an interposer substrate 36, and is packaged by mounting the covering member 20 on the interposer substrate 36, according to which the shape Into a protective component package 37. The interposer substrate 36 has connection electrodes 37a connected to external connection electrodes (connected to the first and second external connection electrodes 11a, 12a or the heating body electrode 19), and is further mounted on the circuit board 2 by reflow soldering assembly or the like. In addition, the covering member 20 is connected to the intermediate substrate 36 by a thermosetting adhesive having excellent connection reliability or the like, or connected by means such as ultrasonic welding.

The cover member 20 of the protective element package 37 has a large internal space that covers the entire protective element 35 and constitutes the package exterior. Therefore, even when the reflow soldering structure and the fusing of the soluble conductor 13 occur, the gas inside the element expands. In the event of a situation, the internal pressure rise is also extremely low, with sufficient patience. Therefore, the protective element package 37 can prevent poor connection or damage of the covering member 20 caused by the increase in the internal pressure of the protective element 35.

[Modification 4]

In addition, as shown in FIG. 11, the protective element 1 may use a covering member 38 without the partition wall member 33 and the top surface 22, and fill the partition wall top surface 33b of the partition wall member 33 with a thermosetting resin 24a Or a sealing member 24 made of photocurable resin. In the protection element 1 shown in FIG. 11, since the side surface 21 of the covering member 38 and the partition wall side surface 33a of the partition wall member 33 and the upper surface of the partition wall top surface 33b are fixed by resin, the covering member 38 and the partition wall can be lifted The connection strength of the member 33 to the insulating substrate 10.

In addition, the partition wall member 33 may be another member different from the covering member 38, or may be integrally molded with the covering member 38.

[Modification 5]

In addition, the protective element 1 may also be used as a sealing member 24 for sealing the vent hole 23 as shown in FIG. 12, in addition to an adhesive such as a thermosetting resin 24a, and a fitting pin fitted in the vent hole 23 24b. The protective element 1 shown in FIG. 12 is provided with a fitting pin 24b in the vent hole 23 for locking 的卡止段部39。 In addition, the vent hole 23 is formed in a cylindrical shape depending on the shape of the fitting pin 24b. In addition, the vent holes 23 may be formed above the first and second electrodes 11 and 12 along the first and second side surfaces 10b and 10c. Except as shown in FIG. 12, the vent hole 23 may be provided above the first and second heating element electrodes 18 and 19.

In the protective element 1, as the sealing member 24, in addition to the thermosetting resin 24a and other adhesives, the use of the fitting pin 24b fitted into the vent hole 23 can not only seal the vent hole 23 more reliably, but also The connection strength of the covering member 20 is improved.

In addition, the fitting pin 24b can be locked to the locking section 39, or may be press-fitted into the vent hole 23, for example. At this time, the vent hole 23 may be formed as a tapered portion whose diameter is expanded toward the top surface 22 side into a tapered shape, and similarly, the fitting pin 24b may be formed into a tapered shape whose diameter decreases toward the tip. Alternatively, the vent hole 23 and the fitting pin 24b may be screwed to each other. In addition, the vent hole 23 and the fitting pin 24b can form a guide convex portion on one side, and a guide concave portion for sliding the guide convex portion on the entire surface of the insertion direction of the fitting pin 24b on the other side.

[Modification 6]

In addition, as shown in FIG. 13, the protective element 1 can use only the fitting pin 24b as the sealing member 24 for sealing the vent hole 23. In this case, from the viewpoint of increasing the connection strength of the covering member 20, it is preferable that the fitting pin 24b is connected to the insulating substrate 10. For example, a thread may be formed on the fitting pin 24b and screwed into a screw hole provided on the surface 10a of the insulating substrate 10, so that the covering member 20 is screwed to the insulating substrate 10. In addition, it is also possible to form a sharp front end on the fitting pin 24b and insert it into the surface 10a of the insulating substrate 10 for connection.

In addition, in the configuration shown in FIG. 13, the fitting pin 24b can be locked to the locking section 39 and can also be press-fitted into the vent hole 23, for example. At this time, the vent hole 23 can be formed to face the top surface The 22 side is expanded into a tapered portion in a tapered shape. Similarly, the fitting pin 24b can be formed in a tapered shape that decreases in diameter toward the tip. Alternatively, the vent hole 23 and the fitting pin 24b may be screwed to each other. In addition, the vent hole 23 and the fitting pin 24b can form a guide convex portion on one side, and a guide concave portion for sliding the guide convex portion on the entire surface of the insertion direction of the fitting pin 24b on the other side.

[Reference example 2]

Next, the structure of the protection element package 37 of the reference example of the present technology will be described with reference to FIG. 14. The protective element 40 shown in FIGS. 14(A) to (C) is what is used to lock the locking piece 42a formed on the side surface 42 of the covering member 41 on the back surface 10f of the insulating substrate 10. The covering member 41 has an inner dimension that is approximately the same as that of the insulating substrate 10, and a pair of side surfaces 42 facing each other is formed with a locking piece 42 a that is locked to the back surface 10 f of the insulating substrate 10.

The covering member 41 is inserted from the front surface 10a side of the insulating substrate 10, and the locking piece 42a is locked to the back surface 10f of the insulating substrate 10, thereby forming a component exterior body. In addition, in the protection element 40, by fitting the covering member 41 to the insulating substrate 10, an internal space 25 for the soluble conductor 13 to melt and flow is formed between the top surface 43 and the surface 10a of the insulating substrate 10.

For the protection element 40, by locking the locking piece 42a on the back 10f of the insulating substrate 10, the covering member 41 and the insulating substrate 10 are firmly connected, so even in the reflow assembly or the fusing of the soluble conductor 13 When the gas inside the element expands, it has sufficient resistance to the rise of internal pressure. Therefore, the protection element 40 can prevent poor connection or damage of the covering member 41 caused by the increase in internal pressure.

〔PCB〕

Next, the circuit board 2 on which the protective element 1 is packaged will be described. The circuit board 2 is a known one that uses a rigid substrate such as a glass epoxy substrate, a glass substrate, a ceramic substrate, etc., or a flexible substrate, etc. Insulating substrate. In addition, the circuit board 2, as shown in Figs. 1 and 2, has a package portion for mounting the protective element 1 on the surface by reflow soldering, etc., and a connecting electrode is provided in the package portion, and the connecting electrode is connected to the protective device. The external connection electrodes 11a and 12a of the back surface 10f of the insulating substrate 10 of the element 1 and the external connection electrode 19a connected to the second heating element electrode 19 are respectively connected. In addition, on the circuit board 2, an element such as an FET for energizing the heating element 14 of the protection element 1 is built.

[How to use the circuit module]

Next, the method of using the protection element 1 and the circuit module 3 in which the surface of the protection element 1 is mounted on the circuit board 2 will be described. As shown in FIG. 15, the circuit module 3, for example, is used as a circuit in a battery pack of a lithium ion secondary battery.

For example, the protection element 1 is used by incorporating a battery pack 50 having a battery stack 55 composed of batteries 51 to 54 of a total of four lithium ion secondary batteries.

The battery pack 50 includes: a battery stack 55, a charge-discharge control circuit 60 that controls the charging and discharging of the battery stack 55, a protection element that interrupts charging when the battery stack 55 is abnormal to which the present invention is applied, and detects one of the batteries 51 to 54 A voltage detection circuit 56 and a current control element 57 that controls the operation of the protection element 1 based on the detection result of the detection circuit 56.

The battery stack 55 is a series connection of the batteries 51 to 54 that need to be protected from overcharge and overdischarge. The positive terminal 50a and the negative terminal 50b of the battery pack 50 are connected to the charging device in a removable manner. 65, the charging voltage from the charging device 65 is applied. The positive terminal 50a and the negative terminal 50b of the battery pack 50 charged by the charging device 65 are connected to an electronic device operated by a battery, that is, the electronic device can be operated.

The charge and discharge control circuit 60 includes two current control elements 61, 62 connected in series in the current path from the battery stack 55 to the charging device 65, and control these current control elements 61, 62 of the action control unit 63. The current control elements 61 and 62 are composed of, for example, field-effect transistors (hereinafter referred to as FETs), and the gate voltage is controlled by the control unit 63 to conduct conduction and interruption of the current path of the battery stack 55 accordingly. The control unit 63 operates by receiving the power supply from the charging device 65, and according to the detection result of the detection circuit 56, when the battery stack 55 is over-discharged or over-charged, it controls the operation of the current control elements 61 and 62 to block the current path.

The protection element 1 is, for example, connected to the charge and discharge current path between the battery stack 55 and the charge and discharge control circuit 60, and its action is controlled by the current control element 57.

The detection circuit 56 is connected to the batteries 51 to 54, detects the voltage values of the batteries 51 to 54, and supplies the voltage values to the control unit 63 of the charge and discharge control circuit 60. In addition, the detection circuit 56 outputs a control signal for controlling the current control element 57 when any one of the batteries 51 to 54 reaches an overcharge voltage or an overdischarge voltage.

The current control element 57 is composed of, for example, a FET. The detection signal output from the detection circuit 56 causes the protection element 1 to operate when the voltage value of the batteries 51 to 54 exceeds a predetermined overdischarge or overcharge state. The switching action of the current control elements 61 and 62 interrupts the charging and discharging current path of the battery stack 55.

In the battery pack 50 configured in the above manner, the configuration of the protection element 1 will be described in detail later.

First, the protection element 1 to which the present invention is applied has a circuit configuration as shown in FIG. 16. That is, the protection element 1 is constituted by a circuit composed of a soluble conductor 13 connected in series through the heating element lead electrode 16 and a heating element 14 which is energized and heated through the connection point of the soluble conductor 13 to melt the soluble conductor 13. In addition, in the protection element 1, for example, the soluble conductor 13 is connected in series on the charging and discharging current path, and the heating element 14 is connected to the current control element 57. The first electrode 11 of the protection element 1 The second electrode 12 is connected to the open end of the battery stack 55 through the external connection electrode 11a, and the second electrode 12 is connected to the open end on the positive terminal 50a side of the battery pack 50 through the external connection electrode 12a. In addition, the heating element 14 is connected to the soluble conductor 13 through the heating element lead-out electrode 16, is connected to the charging and discharging current path of the battery pack 50 accordingly, and is connected to the current control element 57 through the second heating element electrode 19 and the external connection electrode.

In this type of battery pack 50, when the heating element 14 of the protection element 1 is energized to generate heat, the soluble conductor 13 melts and is drawn to the heating element lead electrode 16 due to its wettability. As a result, the protection element 1 can reliably block the current path due to the fusion of the soluble conductor 13. In addition, since the soluble conductor 13 is fused and the power supply path to the heating element 14 is also blocked, the heating of the heating element 14 is also stopped.

In addition, when a large current exceeding the rating of the protection element 1 flows in the battery pack 50 on the charging and discharging path, an unexpectedly large current can be fused by the soluble conductor 13 due to self-heating (Joule heat), thereby blocking the current path.

As described above, the protective element 1 is sealed by the sealing member 24 in the air vent 23, so when the circuit board 2 is reflowed, or the soluble conductor 13 is melted, the air inside the element expands to increase the internal pressure. When it is high, the connection strength between the covering member 20 and the insulating substrate 10 can also be improved, and the covering member 20 can be prevented from being peeled off or damaged from the insulating substrate 10.

In addition, the protection element 1 to which this technology is applied is not limited to the case of being used in a battery pack of a lithium ion secondary battery, and of course can also be applied to various applications where electrical signals must be used to interrupt the current path. In addition, the protection element 1 to which the present technology is applied may also be configured as a fuse element that does not include the heating element 14 and only performs self-heating and interruption at the time of overcurrent.

1‧‧‧Protection components

2‧‧‧Circuit board

3‧‧‧Circuit Module

10‧‧‧Insulating substrate

10a‧‧‧The surface of the insulating substrate

10f‧‧‧The back of the insulating substrate

11‧‧‧The first electrode

11a‧‧‧External connection electrode

12‧‧‧Second electrode

12a‧‧‧External connection electrode

13‧‧‧Fusible Conductor

14‧‧‧Heating body

15‧‧‧Insulation member

16‧‧‧Extruding electrode of heating element

17‧‧‧Flux

20‧‧‧covering member

21‧‧‧Side

22‧‧‧Top surface

23‧‧‧Vent

24‧‧‧Sealing components

24a‧‧‧Thermosetting resin

25‧‧‧Internal space

26‧‧‧Adhesive

27‧‧‧The next wall

Claims (11)

A protection element includes: an insulating substrate; first and second electrodes arranged on the insulating substrate; a soluble conductor arranged across the first and second electrodes; and a covering member arranged on the insulating substrate The side of the side where the soluble conductor is arranged; a vent hole is provided so that the inner space where the soluble conductor is arranged faces the outside of the element; the vent hole is sealed by a sealing member, which has a glass transfer temperature lower than the reflow soldering temperature Point of resin. For example, the protective element in the first item of the scope of patent application, wherein the glass transition point of the resin is above 100°C. Such as the protection element of the first item in the scope of patent application, wherein the sealing member is fitted into the fitting member of the vent hole. For example, the protection element of any one of items 1 to 3 in the scope of patent application, wherein the vent is provided in the covering member. Such as the protection element of item 4 in the scope of patent application, wherein the vent hole is provided with a protrusion protruding from the inside of the vent hole on the inner side. For example, the protection element of item 4 of the scope of patent application, wherein the vent hole is provided with a tapered portion whose inner surface is formed into a tapered shape in a cross-sectional view. Such as the protection element of item 1 or 2 of the scope of patent application, wherein the covering member has a partition wall member forming the internal space; and the resin is filled between the covering member and the partition wall member. Such as the protection element of item 7 of the scope of patent application, wherein the resin is filled between the top surface of the covering member and the top surface of the partition wall member. For example, the protection element of item 7 of the scope of patent application, wherein a covering member without a top surface is used, and the top surface of the partition wall member is filled with the resin. A circuit module has a protection element and a circuit substrate with the protection element on the surface; the protection element includes: an insulating substrate; first and second electrodes arranged on the insulating substrate; a soluble conductor, Arranged across the first and second electrodes; and the covering member is arranged on the side of the insulating substrate where the soluble conductor is arranged; vent holes are provided to make the inner space where the soluble conductor is arranged face the outside of the element ; The vent is sealed by a sealing member, the sealing member is a resin with a lower glass transition point than the reflow soldering temperature. A method for manufacturing a protective element, which is to form a first and a second electrode on an insulating substrate, and arrange a soluble conductor across the first and second electrodes; to mount a covering member on the insulating substrate through a thermosetting resin, A structure having a vent hole where the inner space where the soluble conductor is arranged faces the outside of the element is formed; the structure is heated to connect the covering member to the insulating substrate; the vent hole is sealed with a sealing member.

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