Wiring module

Abstract

To provide a wiring module that can improve the reliability of an appearance inspection of brazing.SOLUTION: A wiring module includes: a flexible printed circuit board 10 including a plurality of distribution lines, a plurality of lands 16 to each of which one end of each of the distribution lines is connected; and a plurality of metal pieces (metal plates 20) that are arranged overlapping the lands 16 and blazed to the lands 16. A through hole 24 is formed in the thickness direction inside an outer peripheral edge of the metal plate 20. The metal plate 20 has an overhang part 25 has at least a portion of an edge of the through hole 24 that protrudes to the opposite side to a side blazed to the land 16 in the thickness direction. A surface of the overhang part 25 is provided with a plating formation part 25a and a plating non-formation part 25b. The plating formation part 25a is arranged at a base end 25c on an inner peripheral side of the overhang part 25 facing through hole 24. The plating non-formation part 25b is arranged at an end face 25d that is an overhanging tip of the overhang part 25.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a wiring module including a flexible printed circuit board.

Background Art

[0002] Patent Document 1 describes soldering a metal piece (described as a metal plate in the same document) to a land provided on a flexible printed circuit board. Generally, these joints are made by brazing such as soldering.

[0003] Also, the metal piece is often formed of a material on which a passivation film such as nickel or aluminum is easily formed, and is often subjected to plating treatment. For example, tin plating may be applied as plating having excellent solder connectivity (the film is soft and the melting point is low) to a portion of the metal piece that is connected to the land via solder. Then, an inspector visually checks the fillet formed by brazing on this plating to determine whether the brazing has been properly performed. And it is generally performed to form a through hole in the metal piece and solder-connect the inner edge surface of this through hole to the land.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in addition to the inner edge surface of the through hole, if plating is continuously formed up to the surface on the side opposite to the side facing the land, the fillet may be formed up to the surface on the side opposite to the side facing the land. In this case, the fillet formed on the inner edge surface (the portion facing the through hole) of the through hole, which is the object of the appearance inspection for soldering, may become thin. Thus, the thickness of the fillet may affect the appearance inspection (visual inspection, inspection by image or X-ray) of soldering. Therefore, there was room for improvement in enhancing the reliability of the appearance inspection of soldering.

[0006] The present invention has been made in view of the above problems, and provides a wiring module capable of enhancing the reliability of the appearance inspection of soldering.

Means for Solving the Problems

[0007] The wiring module according to the present invention includes a flexible printed circuit board having a plurality of wirings and a plurality of lands to which one end of each of the wirings is connected, and a plurality of metal pieces disposed so as to overlap the lands and soldered to the lands. A through hole is formed in the thickness direction inside the outer peripheral edge of the metal piece. The metal piece has an overhanging portion that overhangs to one side where at least a part of the edge of the through hole is on the side opposite to the side soldered to the land in the thickness direction. A plating formation portion and a non-plating formation portion are provided on the surface of the overhanging portion. The plating formation portion is disposed at the base end portion on the inner peripheral side of the overhanging portion facing the through hole, and the non-plating formation portion is disposed at the end surface of the overhanging portion at the overhanging tip.

Effects of the Invention

[0008] According to the wiring module of the present invention, it is possible to enhance the reliability of the appearance inspection of soldering.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0010] Hereinafter, a wiring module according to an embodiment of the present invention will be described with reference to the drawings. Note that the embodiments described below are merely examples for facilitating the understanding of the present invention and do not limit the present invention. That is, with respect to the shapes, dimensions, arrangements, etc. of the members described below, they can be changed and improved without departing from the spirit of the present invention, and it goes without saying that equivalents thereof are included in the present invention.

[0011] Note that the drawings used in this embodiment illustrate the configuration, shape of the wiring module of the present invention, and the arrangement of each member constituting the wiring module, and do not limit the present invention. Also, the drawings do not necessarily accurately represent dimensional ratios such as the length, width, and height of the wiring module. In all the drawings, the same reference numerals are assigned to the same components, and the description thereof will be omitted as appropriate.

[0012] <First Embodiment> <Overview> First, regarding the overview of the present invention, with reference mainly to FIGS. 1 to 4, the wiring module 100 according to the first embodiment will be described as an example. FIG. 1 is a plan view showing the wiring module 100 according to the first embodiment and a plurality of battery cells 70 connected to the wiring module 100. FIG. 2 is a plan view showing a state in which an end portion 15 of an extension portion 12 of the flexible printed circuit board 10 is connected to a protruding portion 22 of the metal plate 20. FIG. 3 is an explanatory view schematically showing a state in which the flexible printed circuit board 10 and the metal plate 20 are connected, and shows an overhanging portion 25 provided on the metal plate 20. FIG. 4 is an end view showing the overhanging portion 25 and the fillet 18a in the IV-IV cross section of FIG. 3.

[0013] In FIG. 1, illustration of a fixing member for fixing the metal plate 20 to the battery cell 70 is omitted. Also, FIG. 2 shows an enlarged view of one metal plate 20 and an end portion 15 of one extension portion 12 corresponding to the metal plate 20 on the flexible printed circuit board 10. Also, FIG. 3 is a view mainly for explaining the overhanging portion 25 provided at the connection portion between the flexible printed circuit board 10 and the metal plate 20, and is an illustration in which a part of the metal plate 20 (the protruding portion 22 in FIG. 1) and a part of the flexible printed circuit board 10 (the end portion 15) are cut away. In FIG. 3, the thickness of the plating is shown thicker than the actual thickness.

[0014] As shown in FIGS. 1 and 2, the wiring module 100 according to the first embodiment includes a flexible printed circuit board 10 having a plurality of wirings 17 (see FIG. 2) and a plurality of lands 16 each connected to one end of the wiring 17, and a plurality of metal pieces (metal plates 20) disposed overlapping the lands 16 and brazed to the lands 16. As shown in FIG. 2, a through hole 24 is formed in the thickness direction inside the outer peripheral edge 20a of the metal plate 20. As shown in FIGS. 3 and 4, the metal plate 20 has an overhanging portion 25 that protrudes on one side opposite to the side where at least a part of the edge of the through hole 24 is brazed to the land 16 in the thickness direction. As shown in FIG. 4, a plating formation portion 25a and a non-plating formation portion 25b are provided on the surface of the overhanging portion 25. The plating formation portion 25a is disposed at the base end portion 25c on the inner peripheral side of the overhanging portion 25 facing the through hole 24, and the non-plating formation portion 25b is disposed at the end face 25d of the overhanging tip of the overhanging portion 25.

[0015] The metal plate 20 of the "metal piece" according to the present invention may be a bus bar for connecting a plurality of battery cells 70 in series, or a metal tab (not shown) as an intermediate member connected to the bus bar. In the present embodiment, an example where the metal plate 20 is a bus bar will be described. Note that the "metal piece" does not necessarily have to be entirely flat, and it is sufficient if a flat portion is provided at the portion brazed to the land 16. Further, the above metal piece is not limited to those related to the bus bar connected to the battery cell 70, and may be connected to a completely different conductive member (for example, a lead wire).

[0016] Also, "brazing" includes soldering and brazing, and in the present embodiment, soldering will be described as an example. In the present embodiment, in FIGS. 3 and 4, the side of the metal plate 20 in the thickness direction where the metal plate 20 is brazed is the lower side, the side where the overhanging portion 25 protrudes is the upper side, and the end face of the overhanging tip of the overhanging portion 25 where the non-plating formation portion 25b is formed is the upper surface.

[0017] As described above, an overhang portion 25 is formed at least in part at the edge of the through hole 24 in the metal piece (metal plate 20). A plating formation portion 25a is disposed at the base end portion 25c on the inner peripheral side of the overhang portion 25, and a non-plating formation portion 25b is disposed at the end face 25d at the overhanging tip. According to such a configuration, the fillet 18a can be concentrated (gathered) at the base end portion 25c on the inner peripheral side of the overhang portion 25, and in an appearance inspection, the fillet 18a can be made easier to detect. Note that the appearance inspection of the brazing for the fillet 18a may be a visual inspection by an inspector, or an inspection using an X-ray inspection machine, in addition to the inspection by an image inspection device.

[0018] Further, when forming the overhang portion 25 by bending the outer peripheral edge 20a of the metal piece (metal plate 20) shown in FIG. 2, the land 16 should be made slightly larger than the joint portion between the metal plate 20 and the land 16 so that the fillet 18a can be visually recognized or the like. On the other hand, when providing the overhang portion 25 at the edge of the through hole 24 formed in the metal plate 20 to form the fillet 18a, the size relationship between the metal plate 20 and the land 16 can be arbitrarily set, so the degree of design freedom is increased.

[0019] Hereinafter, the present embodiment will be described in more detail. As shown in FIG. 1, the wiring module 100 includes a flexible printed circuit board 10 and a plurality of metal plates 20, and a plurality of battery cells 70 are connected in series by these metal plates 20. The battery cell 70 is a secondary battery.

[0020] The flexible printed circuit board 10 according to the present embodiment is used for monitoring voltage, for example, by connecting the wiring 17 to a bus bar (metal plate 20) that connects a plurality of battery cells 70. The flexible printed circuit board 10 has, for example, a connector attached thereto, and is connected to a measuring device that performs various controls via the connector, enabling voltage monitoring. As shown in FIG. 1, the flexible printed circuit board 10 includes a flat main body portion 11 and a plurality of extending portions 12 extending from the edge of the main body portion 11.

[0021] The shape of the extending portion 12 is not particularly limited. As an example, as shown in FIG. 1, it has a bent shape. The extending portion 12 has, at its tip, an end portion 15 formed wider than the portion on the proximal end side of the end portion 15 in the extending portion 12. As an example, the entire extending portion 12 is arranged on the same plane. The planar shape of the end portion 15 is not particularly limited. As an example, it is rectangular (for example, a rectangular shape with rounded corners).

[0022] As shown in FIG. 2, a land 16, which is a thin film of a conductor such as metal, is formed on the end portion 15. The planar shape of the land 16 is not particularly limited. As an example, it is rectangular (for example, a rectangular shape with rounded corners). In the case of this embodiment, the area of the land 16 is smaller than the area of the protruding portion 22, and as shown in FIG. 2, when viewed in the thickness direction of the metal plate 20 (in plan view), the land 16 is contained inside the outer contour line of the protruding portion 22 of the metal plate 20.

[0023] Note that the land 16 is formed without a gap so as to cover the upper surface of the end portion 15 of the flexible printed circuit board 10 in the region facing the through hole 24, but is not limited to such a configuration, and a part of the land 16 may not be formed. According to such a configuration, the formation region of the fillet 18a can be limited to the formation region of the land 16, and when the metal plate 20 is soldered to the land 16, the positional accuracy of the metal plate 20 with respect to the land 16 can be automatically and favorably controlled by the surface tension of the molten solder 18.

[0024] The flexible printed circuit board 10 includes a plurality of wirings 17 (see FIG. 2) each extending from the main body portion 11 to the end portion 15 of each extending portion 12. For example, one wiring 17 is arranged for each individual extending portion 12. One land 16 is formed on each end portion 15, and the tip of each wiring 17 is connected to the corresponding land 16.

[0025] The metal plate 20 according to this embodiment is a bus bar for connecting a plurality of battery cells 70 in series, and is formed, for example, in a flat plate shape. As shown in FIG. 2, for example, the metal plate 20 has a main body portion 21 and a protruding portion 22 that has a width dimension smaller than that of the main body portion 21 and protrudes from the main body portion 21. The planar shape of the main body portion 21 is not particularly limited, but as an example, it is rectangular (for example, a rectangular shape with rounded corners). The main body portion 21 has two fixing holes 23 for fixing and electrically connecting the main body portion 21 to two battery cells 70 arranged adjacent to each other. Note that when the metal plate 20 is a metal tab connected to a bus bar, the metal plate 20 may not have the fixing holes 23.

[0026] The protruding portion 22 is formed so as to protrude from the main body portion 21 in order to be connected to a land 16 provided on the flexible printed circuit board 10 via a solder 18. The planar shape of the protruding portion 22 is not particularly limited, but as an example, it is rectangular (for example, a rectangular shape in which two corner portions on the tip side in the protruding direction are rounded). A through hole 24 is formed in the protruding portion 22, and an overhanging portion 25 that protrudes upward is formed on the inner edge of the through hole 24. The through hole 24 penetrates the metal plate 20 (the protruding portion 22 thereof) in the thickness direction.

[0027] The number of through holes 24 provided in each metal plate 20 is not particularly limited, but in the case of this embodiment, one through hole 24 is formed in each metal plate 20 (each protruding portion 22 thereof). The planar shape of the through hole 24 is not particularly limited, but in the case of this embodiment, it is, for example, circular. However, the planar shape of the through hole 24 may be rectangular and can be made into an arbitrary shape as described later. As shown in FIG. 4, the protruding portion 22 of the corresponding metal plate 20 is joined to the land 16 of each extending portion 12 via a solder 18.

[0028] As shown in FIG. 3, the overhanging portion 25 is formed over the entire circumference of the edge of the through hole 24. In FIG. 4, the overhanging portion 25 is shown as bending at a right angle from another portion continuous with the base end side of the overhanging portion 25 in the protruding portion 22 and protruding upward. However, the present invention is not limited to such a configuration. For example, a rounded portion may be formed at this bending portion. That is, it goes without saying that it may curve from the above-mentioned other portion and protrude upward. The same applies to the overhanging portions 35, 45, 55, and 65 described later.

[0029] The metal plate 20 is subjected to a partial plating process in a region where at least a part can be within the connection range of the flexible printed circuit board 10. As shown in FIGS. 3 and 4, the plating formation portion 25a is disposed over the entire circumference on the inner peripheral side of the overhanging portion 25. As shown in FIG. 4, the non-plating formation portion 25b is disposed over the entire circumference of the end face 25d at the protruding tip at the edge of the through hole 24.

[0030] According to the above configuration, the plating formation portion 25a where solder is easily connected is disposed over the inner circumference of the overhanging portion 25, and the non-plating formation portion 25b where solder is difficult to connect is disposed over the entire circumference of the end face 25d at the protruding tip, making it easy to form the fillet 18a in an annular shape. Therefore, the connection strength by soldering can be increased by the annularly formed fillet 18a.

[0031] In addition, the plating formation portion 25a according to the present embodiment is formed not only on the inner peripheral side of the overhanging portion 25 but also on the lower surface portion of the protruding portion 22 (the portion on the side placed on the land 16) around the inner peripheral side. Further, the plating formation portion 25a is also formed on the upper surface portion of the overhanging portion 25 on the outer peripheral side and around it.

[0032] [First Modified Example] In FIG. 4, the overhanging portion 25 according to the above embodiment is shown as being formed with an equal height, but the present invention is not limited to such a configuration. Next, the overhanging portion 35 according to the first modification will be described with reference to FIG. 5. FIG. 5 is an end view showing the overhanging portion 35 and the fillets 38a and 38b according to the first modification, and is a view corresponding to FIG. 4.

[0033] As shown in FIG. 5, the highest portion 35f of the overhanging height in the overhanging portion 35 and the lowest portion 35g of the overhanging height are provided on the opposite side in the thickness direction view (the thickness direction view of the metal plate 20 in FIG. 3). The above-mentioned "opposite side" means that in the circular (not limited to a perfect circle, it may be elliptical) through-hole 24, with its center as a reference, the lowest portion 35g is within the range of +90 degrees or more and -90 degrees or less with respect to the highest portion 35f. Also, when the through-hole and the overhanging portion are formed in a rectangular shape, the "opposite side" means the opposite edge side of the rectangular through-hole.

[0034] According to the above configuration, by making the overhanging height of the overhanging portion 35 different, indirectly, the heights of the fillets 38a and 38b of the solder 38 can be adjusted, and it becomes easier to adjust the connection strength for each position of the edge of the through-hole 24.

[0035] Specifically, among the base end portions 35c, a fillet 38a is formed in a large range in the overhanging direction at the portion connected to the highest portion 35f of the overhanging portion 35, and a fillet 38b is formed in a small range in the overhanging direction at the portion connected to the lowest portion 35g of the overhanging portion 35.

[0036] In addition, the overhanging portion 35 having a circular shape in plan view (thickness direction view) is formed so as to have continuously different heights in the circumferential direction of the through-hole 24, including the highest portion 35f and the lowest portion 35g of the overhanging portion 35. By being formed in this way, it becomes easier to continuously form the height of the entire fillet including the fillets 38a and 38b formed along the circular overhanging portion 35 in the circumferential direction of the through-hole 24, and it becomes easier to prevent stress concentration from occurring in the fillet.

[0037] [Second Modification Example] In the above embodiment, as shown in FIGS. 4 and 5, the end face 25d of the overhanging portion 25 and the end face 35d of the overhanging portion 35 are formed parallel to the upper surface of the protruding portion 22 and the upper surface of the land 16. However, the present invention is not limited to such a configuration. Next, referring to FIG. 6, the overhanging portion 45 according to the second modification will be described. FIG. 6 is an end view showing the overhanging portion 25 and the fillet 18a according to the second modification, and is a view corresponding to FIG. 4.

[0038] As shown in FIG. 6, the end face 45d at the protruding end of the overhanging portion 45 is formed to be inclined downward toward the other side in the thickness direction as it goes toward the inner peripheral side. The above-mentioned "inner peripheral side" means the inner peripheral side of the through-hole 24. The above-mentioned "the other side in the thickness direction" is the lower side in FIG. 6 and the land 16 side. The above-mentioned "downward inclination" means that it is inclined so as to be close to the upper surface of the land 16.

[0039] According to the above configuration, even if the fillet 18a is temporarily disposed on the end face 45d where the non-plated portion 25b of the overhanging portion 45 is located, due to the downward inclination of the end face 45d, the self-weight of the fillet 18a acts in the direction (downward) toward the land 16. Therefore, it becomes easier to move the fillet 18a toward the plating formation portion 25a.

[0040] Particularly in the present embodiment, the base end portion 45c of the overhanging portion 45 is formed to be inclined toward the inner peripheral side of the through-hole 24 rather than in a direction parallel to the thickness direction of the metal plate 20. By being formed in this way, compared with the case where the base end portion 45c of the overhanging portion 45 projects parallel to the thickness direction of the metal plate 20, the gap with the land 16 can be narrowed, and the bonding force by the fillet 18a can be increased. In addition, the downward inclination angle of the end face 45d of the overhanging portion 45 with respect to the upper surface of the land 16 can be made larger.

[0041] The base end portion 45c of the protruding portion 45 only needs to be inclined at least slightly toward the inner peripheral side of the through hole 24 rather than in a direction parallel to the thickness direction of the metal plate 20. When the base end portion 45c is inclined toward the inner peripheral side in this way, the formation region of the fillet 18a can be secured in the vertical direction, horizontal direction, and depth direction (direction parallel to the upper surface of the protruding portion 22) in FIG. 6, which is preferable.

[0042] [Third Modified Example] Regarding the protruding portions 25, 35, and 45 according to the above-described embodiment, although there has been no mention of the formation of a groove, particularly on the inner peripheral surface side, a groove 55i described below may be formed. Next, the protruding portion 55 according to the third modified example will be described with reference to FIG. 7. FIG. 7 is a cross-sectional view showing the protruding portion 55 according to the third modified example in the IV-IV cross-section of FIG. 3. In FIG. 7, for the sake of explanation of the configuration, the width of the groove 55i is shown larger than the actual width.

[0043] As shown in FIG. 7, a groove 55i extending in the protruding direction (the vertical direction in this example) is formed on the inner peripheral side of the protruding portion 55. The groove 55i is formed shallower than the thickness of the plating formation portion 25a.

[0044] In other words, the above-mentioned "inner peripheral side of the protruding portion 55" is the inner peripheral surface side of the through hole 24. The groove 55i is formed by being recessed from the surface of the plating formation portion 25a toward the inside in the thickness direction of the protruding portion 55. The above-mentioned "extending in the protruding direction" means, in other words, extending along the extending direction of the inner peripheral surface of the protruding portion 55, and is not necessarily limited to extending linearly.

[0045] According to the above configuration, since the groove 55i is formed on the inner peripheral side of the protruding portion 55, the fillet 18a enters the groove, so that the connection strength between the fillet 18a and the metal plate 20 can be increased. Furthermore, since the groove 55i is formed thinner than the thickness of the plating formation portion 25a, it is possible to prevent the metal plate 20 from being exposed from the plating formation portion 25a. Regarding the groove 55i, as shown in FIG. 7, if a plurality of grooves are formed over the entire inner peripheral side of the overhanging portion 55, it is preferable because the connection strength between the fillet 18a and the metal plate 20 can be evenly increased on the inner peripheral side of the overhanging portion 55.

[0046] In addition, in FIG. 7, the width of the groove 55i is shown to be larger than the thickness of the plating formation portion 25a. However, the present invention is not limited to such a configuration, and the width of the groove 55i may be the same as or smaller than the thickness of the plating formation portion 25a.

[0047] [Second Embodiment] Regarding the overhanging portions 25, 35, and 45 according to the above embodiment, an example in which the entire circumference of the inner edge of the through hole 24 formed in a circular shape in plan view protrudes upward has been described. However, the present invention is not limited to such a configuration. Next, the overhanging portion 65 according to the second embodiment formed at a part of the edge of the through hole 64 will be described with reference to FIGS. 8 and 9. FIG. 8 is a schematic perspective view showing the overhanging portion 65 and the through hole 64 according to the second embodiment, and FIG. 9 is an end view showing the overhanging portion 65 and the fillet 18a in the IX-IX cross section of FIG. 8.

[0048] The edge of the through hole 64 according to the present embodiment has an extension portion 64a that extends toward the center side of the through hole 64 in the surface direction of the metal piece (metal plate 20). The through hole 64 has slits 64b formed on both sides of the extension portion 64a. The overhanging portion 65 is formed at the tip of the extension of the extension portion 64a.

[0049] Specifically, the through hole 64 according to the present embodiment is formed in a vertically long C shape with corners as shown in FIG. 8 in a view in the thickness direction. Both ends of the C shape of the through hole 64 are the slits 64b, and the extension portion 64a is formed between the slits 64b. An overhanging portion 65 extending upward as shown in FIG. 9 is provided at the tip of the extension portion 64a.

[0050] The "surface direction of the metal piece (metal plate 20)" as described above shall refer to any direction within the plane including the lateral direction and the depth direction in FIG. 9. Since the overhanging portion 65 is formed at the tip of the extending portion 64a in this way, when the overhanging portion 65 is bent to one side in the thickness direction, compared with the case where it is formed so as to protrude in the thickness direction without passing through the extending portion 64a from the edge of the through hole 64, it is possible to suppress the occurrence of a wrinkled bulge (not shown) due to stress concentration at the tips of the slits 64b on both sides of the overhanging portion 65.

[0051] However, the present invention is not limited to such a configuration, and the slits 64b may not be formed on both sides of the overhanging portion 65. That is, an extending portion 64a that extends toward the center of the through hole 64 in the surface direction of the metal piece may not be formed at the edge of the through hole 64, and the overhanging portion 65 may be formed so as to protrude directly upward from the edge of the through hole 64.

[0052] Regarding the through hole 64, although it has been described as having an angularly elongated vertical C shape, it may have a rectangular shape or other shapes. For the through hole formed in this way, it is preferable that the overhanging portion 65 is formed at the edge portion formed in a long shape among the edges of the through hole, because a wider formation region of the fillet 18a can be secured.

[0053] Also, although an example in which the overhanging portion 65 is formed at a part (extending portion 64a) of the edge of the through hole 64 has been described, it may be formed at a plurality of parts of the edge of the through hole 64. According to such a configuration, it becomes easier to form the fillet 18a at the plurality of parts where the overhanging portion 65 is formed, and the connection strength of the plurality of parts can be increased. Furthermore, in these plurality of parts, it is possible to judge the quality of the solder connection.

[0054] The rising height H of the overhanging portion 65 shown in FIG. 9 is preferably in the range of 1.25 times or more and 5 times or less the thickness T of the metal piece (metal plate 20). The above-mentioned "rising height H" shall refer to the height from the lower surface of the protruding portion 22 (the surface facing the land 16) to the end surface 65d of the overhanging portion 65 as shown in FIG. 9. According to the above configuration, by limiting it to 1.25 times or more, a sufficient area where the fillet is formed can be ensured, and by limiting it to 5 times or less, it is possible to prevent the occurrence of a wasteful portion where no fillet is formed on the plating portion provided on the rising portion.

[0055] In addition, it is preferable that the relationship between the rising height H of the overhang portion 65 and the thickness T of the metal plate 20 is the same as the relationship between the height of each of the lowest portions 35g of the overhang portions 25 and 35, the overhang portion 45, and the overhang portion 55 according to the first embodiment and the thickness T of the metal plate 20.

[0056] In addition, the various components of the wiring module (100) of the present invention do not necessarily exist independently. It is acceptable that a plurality of components are formed as one member, one component is formed of a plurality of members, a certain component is a part of another component, a part of a certain component and a part of another component overlap, and the like.

[0057] This embodiment includes the following technical ideas. (1) A flexible printed circuit board having a plurality of wirings and a plurality of lands to which one end of each of the wirings is connected, A plurality of metal pieces disposed so as to overlap the lands and brazed to the lands, A wiring module comprising: A through hole is formed in the thickness direction inside the outer peripheral edge of the metal piece, The metal piece has an overhang portion that protrudes to one side opposite to the side where at least a part of the edge of the through hole is brazed to the land in the thickness direction, A plating formation portion and a non-plating formation portion are provided on the surface of the overhang portion, The plating formation portion is disposed at the base end portion on the inner peripheral side of the overhang portion facing the through hole, The wiring module is characterized in that the non-plating formation portion is disposed on the end face at the protruding end of the overhang portion. (2) The protruding portion is formed over the entire circumference of the edge of the through hole. The plating formation portion is disposed over the entire circumference on the inner circumferential side of the protruding portion. The non-plating formation portion is disposed over the entire circumference of the end face at the protruding end of the edge of the through hole. The wiring module according to (1). (3) The portion with the highest protruding height and the portion with the lowest protruding height in the protruding portion are provided on opposite sides in a view in the thickness direction. The wiring module according to (1) or (2). (4) The end face at the protruding end of the protruding portion is formed to slope downward toward the other side in the thickness direction as it goes toward the inner circumferential side. The wiring module according to any one of (1) to (3). (5) A groove extending in the protruding direction is formed on the inner circumferential side of the protruding portion. The groove is formed shallower than the thickness of the plating formation portion. The wiring module according to any one of (1) to (4). (6) The edge of the through hole has an extending portion that extends toward the center side of the through hole in the surface direction of the metal piece. The through hole has slits formed on both sides adjacent to the extending portion. The protruding portion is formed at the extended end of the extending portion. The wiring module according to (1), or (4) or (5) that cites (1). (7) The rising height of the protruding portion is in the range of 1.25 times or more and 5 times or less the thickness of the metal piece. The wiring module according to any one of (1) to (6).

Explanation of Reference Numerals

[0058] 10 Flexible printed circuit board 11 Body portion 12 Extending portion 15 End portion 16 Land 17 Wiring 18 Solder 18a Fillet 20 Metal plate 20a Outer peripheral edge 21 Body part 22 Protrusion 23 Fixing hole 24 Through hole 25 Overhanging part 25a Plating formation part 25b Non - plating formation part 25c Base end part 25d End face 35 Overhanging part 35c Base end part 35d End face 35f Highest part 35g Lowest part 38 Solder 38a, 38b Fillet 45 Overhanging part 45c Base end part 45d End face 55 Overhanging part 55i Groove 64 Through hole 64a Extension part 64b Slit 65 Overhanging part 65d End face 70 Battery cell 100 Wiring module

Claims

1. A flexible printed circuit board having a plurality of wirings and a plurality of lands each connected to one end of the wiring, and a plurality of metal pieces disposed overlapping the lands and brazed to the lands, a wiring module comprising: a through hole is formed in the thickness direction inside the outer peripheral edge of the metal piece, the metal piece has an overhang portion that projects to one side opposite to the side where at least a part of the edge of the through hole is brazed to the land in the thickness direction, a plating formation portion and a non-plating formation portion are provided on the surface of the overhang portion, the plating formation portion is disposed at the base end portion on the inner peripheral side of the overhang portion facing the through hole, the non-plating formation portion is disposed on the end face of the projecting tip of the overhang portion, a wiring module characterized in that.

2. the overhang portion is formed over the entire circumference of the edge of the through hole, the plating formation portion is disposed over the entire circumference on the inner peripheral side of the overhang portion, the wiring module according to claim 1, wherein the non-plating formation portion is disposed over the entire circumference of the end face of the projecting tip at the edge of the through hole.

3. The wiring module according to claim 1 or 2, wherein the highest portion and the lowest portion of the overhang height of the overhang portion are provided on opposite sides in a view in the thickness direction.

4. The wiring module according to claim 3, wherein the end face of the projecting tip of the overhang portion is formed to be inclined downward toward the other side in the thickness direction as it goes toward the inner peripheral side.

5. the edge of the through hole has an extension portion that extends toward the center side of the through hole in the surface direction of the metal piece, the through hole has slits formed on both sides adjacent to the extension portion, the wiring module according to claim 1, wherein the overhang portion is formed at the extended tip of the extension portion.

6. The wiring module according to claim 5, wherein the rising height of the overhang portion is in the range of 1.25 times or more and 5 times or less the thickness of the metal piece.

Images