Patent Publication Number: US-2022236332-A1

Title: Voltage monitoring module

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from Japanese Patent Application No. 2021-010869 filed with the Japan Patent Office on Jan. 27, 2021, the entire content of which is hereby incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a voltage monitoring module. 
     2. Related Art 
     JP-A-2002-111170 describes a printed circuit board having a cutout formation portion formed at a metal plate soldered to a land. 
     SUMMARY 
     A voltage monitoring module according to the present embodiment includes: a land; and a metal plate arranged on the land and soldered to the land, in which a through-hole is partially formed at a location of the metal plate corresponding to the land, a non-formation area is formed at a location of the land corresponding to part of the through-hole, and no conductor is formed in the non-formation area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view showing a voltage monitoring module according to the present embodiments and multiple battery cells connected to the voltage monitoring module; 
         FIG. 2  is a perspective view of the voltage monitoring module according to the present embodiments: 
         FIG. 3  is a partially-enlarged plan view of a voltage monitoring module according to a first embodiment: 
         FIG. 4A  is a partially-enlarged plan view of the voltage monitoring module according to the first embodiment; 
         FIG. 4B  is a cut end view along an A-A line of  FIG. 4A : 
         FIG. 5A  is a partially-enlarged plan view of the voltage monitoring module according to the first embodiment: 
         FIG. 5B  is a cut end view along an A-A line of  FIG. 5A ; 
         FIG. 6  is a partially-enlarged plan view of a voltage monitoring module according to a second embodiment: 
         FIG. 7A  is a plan view of an end portion of an extending portion of a flexible printed circuit board included in the voltage monitoring module according to the second embodiment: 
         FIG. 7B  is a plan view of a metal plate of the voltage monitoring module according to the second embodiment: 
         FIG. 7C  is a partially-enlarged plan view of the voltage monitoring module according to the second embodiment: 
         FIG. 8  is a partially-enlarged plan view of a voltage monitoring module according to a third embodiment: 
         FIG. 9A  is a plan view of an end portion of an extending portion of a flexible printed circuit board included in the voltage monitoring module according to the third embodiment: 
         FIG. 9B  is a plan view of a metal plate of the voltage monitoring module according to the third embodiment; 
         FIG. 9C  is a partially-enlarged plan view of the voltage monitoring module according to the third embodiment; 
         FIG. 9D  is a cut end view along an A-A line of  FIG. 9C ; 
         FIG. 9E  is a cut end view along a B-B line of  FIG. 9C ; 
         FIG. 10A  is a partially-enlarged plan view of the voltage monitoring module according to the third embodiment: 
         FIG. 10B  is a cut end view along an A-A line of  FIG. 10A : 
         FIG. 11  is a partially-enlarged plan view of a voltage monitoring module according to a fourth embodiment: 
         FIG. 12A  is a plan view of an end portion of an extending portion of a flexible printed circuit board included in the voltage monitoring module according to the fourth embodiment: 
         FIG. 12B  is a plan view of a metal plate of the voltage monitoring module according to the fourth embodiment: 
         FIG. 12C  is a partially-enlarged plan view of the voltage monitoring module according to the fourth embodiment: 
         FIG. 12D  is a cut end view along an A-A line of  FIG. 12C : 
         FIG. 13  is a plan view of a voltage monitoring module according to a fifth embodiment; and 
         FIG. 14  is a partially-enlarged plan view of a voltage monitoring module according to a reference embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing. 
     The technique disclosed in JP-A-2002-111170 has room for improvement in terms of the accuracy of the position of the metal plate with respect to the land. 
     The present embodiments cope with the above-described problem. According to the present embodiments, a voltage monitoring module capable of achieving the favorable accuracy of the position of the metal plate with respect to the land is provided. 
     According to the present disclosure, provided is a voltage monitoring module which includes: a land; and a metal plate arranged on the land and soldered to the land, in which a through-hole is partially formed at a location of the metal plate corresponding to the land, a non-formation area is formed at a location of the land corresponding to part of the through-hole, and no conductor is formed in the non-formation area. 
     According to the present embodiments, the favorable accuracy of the position of the metal plate with respect to the land can be achieved. 
     Hereinafter, the present embodiments will be described with reference to the drawings. Note that in all drawings, the same reference numerals are used to represent similar components and description thereof will be omitted as necessary. 
     First Embodiment 
     First, a first embodiment will be described with reference to  FIGS. 1 to 5B . 
     Note that in  FIG. 1 , a fixing member for fixing a metal plate  20  to a battery cell  70  is not shown.  FIG. 3  shows, in closeup, an area including one metal plate  20  and an end portion  15  of one extending portion  12  corresponding to the metal plate  20 .  FIGS. 4A and 5A  show an area including the end portion  15  in closeup.  FIGS. 4A and 5A  do not show a wiring  17 . 
     A voltage monitoring module  100  according to the present embodiment includes a flexible printed circuit board  10  ( FIGS. 1 and 2 ) and the multiple metal plates  20 . The flexible printed circuit board  10  has the multiple wirings  17  ( FIG. 3 ) and multiple lands  16  ( FIGS. 3 to 5B ). One end of each wiring  17  is connected to the land  16 . The multiple metal plates  20  are each arranged on the lands  16 , and are each soldered to the lands  16 . 
     A through-hole  24  ( FIGS. 3 to 5B ) is partially formed at a location of the metal plate  20  corresponding to the land  16 . 
     A non-formation area  18  ( FIGS. 3 to 5B ) is formed at a location of the land  16  corresponding to part of the through-hole  24 . No conductor is formed in the non-formation area  18 . 
     In the present embodiment, the metal plate  20  may be a bus bar. Alternatively, the metal plate  20  may be a metal tab connected to a bus bar. In the present embodiment, an example where the metal plate  20  is the bus bar will be described. 
     According to the present embodiment, the through-hole  24  is partially formed at the location of the metal plate  20  corresponding to the land  16 . Thus, voids contained in molten solder  30  can be removed through the through-hole  24 . As a result, the voids remaining in the solder  30  can be reduced. 
     In addition, the non-formation area  18  is formed at the location of the land  16  corresponding to part of the through-hole  24  of the metal plate  20 . Further, no conductor is formed in the non-formation area  18 . With this configuration, when the metal plate  20  is soldered to the land  16 , the accuracy of the position of the metal plate  20  with respect to the land  16  is naturally favorably controlled by surface tension of the molten solder. Thus, it can be expected that the necessity of using a tool configured to hold the metal plate  20  for holding the position accuracy of the metal plate  20  is eliminated. 
     The non-formation area  18  is arranged at the position corresponding to the through-hole  24 . Thus, a fillet  31  ( FIGS. 4A and 4B ) of the solder  30  can be formed in an inner region of the through-hole  24 . Consequently, even if the land  16  has such dimensions that the land  16  is covered with the metal plate  20 , the exterior appearance of the fillet  31  can be easily inspected by image inspection equipment. Note that the exterior appearance inspection of the fillet  31  may be, other than inspection by the image inspection equipment, visual inspection by an inspector or inspection using an X-ray inspection machine. 
     The non-formation area  18  is arranged at the position corresponding to the through-hole  24 . Thus, a flux used for soldering can flow into the non-formation area  18 . This can suppress the flux from thickly accumulating in the through-hole  24 . Consequently, favorable visibility of the fillet  31  ( FIG. 4B ) of the solder  30  is provided. Moreover, the exterior appearance inspection of the fillet  31  can be easily reliably performed. As a result, the reliability of such exterior appearance inspection can be improved. 
     The fillet  31  can be formed along the inner periphery of the through-hole  24 . Thus, a sufficient total extension of the fillet  31  can be ensured. As a result, a sufficient bonding strength between the land  16  and the metal plate  20  can be ensured. 
     Hereinafter, the present embodiment will be described in more detail. 
     As shown in  FIGS. 1 and 2 , the flexible printed circuit board  10  includes a flat plate-shaped body portion  11  and the multiple extending portions  12  extending from an edge of the body portion  11 . 
     The shape of the extending portion  12  is not specifically limited. In an example shown in  FIG. 2 , the extending portion  12  is formed in a bent shape, and has the end portion  15  at a tip end. 
     The end portion  15  is, for example, formed wider than a portion of the body portion  1 I side of the extending portion  12 . In the example of  FIG. 2 , the entirety of the extending portion  12  is arranged on the same plane. The planar shape of the end portion  15  is not specifically limited. In the example of  FIG. 2 , the planar shape is a rectangular shape having three rounded corner portions. 
     As shown in  FIG. 3 , a thin film of a conductor such as metal is formed as the land  16  on the end portion  15 . 
     The planar shape of the land  16  is not specifically limited. In an example of  FIG. 3 , the planar shape is a rectangular shape having rounded corner portions. 
     The flexible printed circuit board  10  includes the multiple wirings  17 . Each of the multiple wirings  17  extends from the body portion  11  to the end portion  15  of the extending portion  12 . For example, the single wiring  17  is arranged on each extending portion  12 . The single land  16  is formed on each end portion  15 . A tip end of each wiring  17  is connected to a corresponding one of the lands  16 . 
     As described above, the non-formation area  18  is formed at part of the land  16 . No conductor is formed in the non-formation area  18 . That is, adhesion of the solder  30  is reduced because no conductor is present in the non-formation area  18 . 
     The non-formation area  18  is arranged in an island shape inside the outline of the land  16 . 
     The planar shape of the non-formation area  18  is not specifically limited. In the case of the present embodiment, the planar shape is, for example, a rectangular shape elongated in one direction. Note that in the present embodiment, the planar shape of the non-formation area  18  may be other shapes including a circular shape and a polygonal shape other than the rectangular shape. 
     The number of non-formation areas  18  arranged at each land  16  is not specifically limited. In the case of the present embodiment, the single non-formation area  18  is arranged at each land  16 . 
     The metal plate  20  is, for example, formed in a flat plate shape. The metal plate  20  has, for example, a body portion  21  and a protruding portion  22  having a smaller width dimension than that of the body portion  21  and protruding from the body portion  21 . The planar shape of the body portion  21  is not specifically limited. In the example of  FIG. 3 , the planar shape is a rectangular shape having rounded corner portions. The planar shape of the protruding portion  22  is not specifically limited. In the example of  FIG. 3 , the planar shape is a rectangular shape having two rounded corner portion on a tip end side in a protruding direction. 
     The flexible printed circuit board  10  described herein connects the wirings  17  to bus bars connecting the multiple battery cells  70 , thereby monitoring the voltages of the battery cells  70 , for example. That is, in the case of the present embodiment, the metal plates  20  are the bus bars connecting the multiple battery cells  70  in series. 
     In the case of the present embodiment, the voltage monitoring module  100  includes the flexible printed circuit board  10  and the multiple metal plates  20 . These metal plates  20  connect the multiple battery cells  70  in series. 
     The battery cell  70  is, for example, a secondary battery. 
     For example, a connector is attached to the flexible printed circuit board  10 . The flexible printed circuit board  10  can be, via the connector, connected to measurement equipment configured to perform various types of control. In this manner, the voltage can be monitored. 
     In an example of  FIG. 1 , the body portion  21  of the metal plate  20  has two fixing holes  23 . With the fixing holes  23 , adjacent two of the battery cells  70  are fixed and electrically connected to the body portion  21 . Note that in a case where the metal plate  20  is the metal tab connected to the bus bar, the bus bar may have the fixing holes  23  instead of the metal plate  20 . 
     The through-hole  24  is formed at the protruding portion  22 . The through-holes  24  penetrates (the protruding portion  22  of) the metal plate  20  in a thickness direction thereof. 
     The number of through-holes  24  formed at each metal plate  20  is not specifically limited. In the case of the present embodiment, the single through-hole  24  is formed at (the protruding portion  22  of) each metal plate  20 . 
     The planar shape of the through-hole  24  is not specifically limited. In the example of the present embodiment, the planar shape is a rectangular shape elongated in one direction. Note that in the present disclosure, the shape of the through-hole  24  may be other shapes including a circular shape and a polygonal shape other than the rectangular shape. 
     In the case of the present embodiment, the through-hole  24  has a larger area than that of the non-formation area  18 . 
     As shown in  FIGS. 4A to 5B , the protruding portion  22  of each metal plate  20  is bonded to the land  16  of a corresponding one of the extending portions  12  via the solder  30 . 
     In the case of the present embodiment, the land  16  has a smaller area than that of the protruding portion  22 . As shown in  FIGS. 3 and 4A , when viewed in the thickness direction of the metal plate  20 , the land  16  is within the outline of the metal plate  20 . More specifically, the land  16  is within the outline of the protruding portion  22  of the metal plate  20 . Thus, size reduction in the land  16  and therefore the end portion  15  of the extending portions  12  can be achieved. Further, not only space limitations but also layout limitations on each portion of the flexible printed circuit board  10  are loosened. 
     Further, in the case of the present embodiment, when viewed in the thickness direction of the metal plate  20 , the non-formation area  18  is within the through-hole  24 . Thus, when the solder  30  is viewed from the back side, the fillet  31  is formed along the entire inner periphery of the through-hole  24 . Thus, the fillet  31  is more easily checked. 
     For example, as shown in, e.g.,  FIG. 4A , a longitudinal direction of the through-hole  24  and a longitudinal direction of the non-formation area  18  are coincident with each other. In addition, the non-formation area  18  is arranged at a center portion of the through-hole  24 . 
     In the case of the present embodiment, each of the through-hole  24  and the non-formation area  18  is in the rectangular shape. Thus, a condition where at least one of the through-hole  24  or the non-formation area  18  is in a non-circular shape is satisfied. With this configuration, the accuracy of the position of the metal plate  20  with respect to the land  16  is naturally favorably controlled by the surface tension of the molten solder as described above. According to the present embodiment, such a control effect can be more reliably obtained. 
     As shown as an example in  FIG. 5B , a fillet  32  is formed along the outer periphery of the land  16  on a surface of the protruding portion  22  facing an end portion  15  side. The fillet  32  has a shape inverted from that of the fillet  31 . Depending on the amount of solder  30 , the fillet  32  is not necessarily formed across the entire outer periphery of the land  16 . In this case, the fillet  32  may be selectively formed along part of the outer periphery of the land  16 . Alternatively, substantially no fillet  32  may be formed. 
       FIG. 14  is a partially-enlarged plan view of a voltage monitoring module according to a reference embodiment. 
     The voltage monitoring module according to the reference embodiment includes, for example, a flexible printed circuit board having extending portions  212  and metal plates  220 . This flexible printed circuit board has wirings  217 . A tip end of each wiring  217  is connected to a land  216 . The land  216  is arranged on an end portion  215  of the extending portion  212 . 
     For example, two through-holes (a through-hole  224  and a through-hole  225 ) are formed at a protruding portion  222  of the metal plate  220 . Of these through-holes, the through-hole  224  entirely overlaps with the land  216 . On the other hand, part of the through-hole  225  overlaps with the land  216 , but the remaining part of the through-hole  225  does not overlap with the land  216 . 
     No non-formation area  18  is present on the land  216  of the voltage monitoring module according to the reference embodiment. 
     On the other hand, the voltage monitoring module  100  according to the present embodiment is configured such that the non-formation area  18  is formed on the land  16 . Thus, according to the present embodiment, the better effect of reducing position shift between the land  16  and the metal plate  20  is provided as compared to the voltage monitoring module according to the reference embodiment. 
     Second Embodiment 
     Next, a second embodiment will be described with reference to  FIGS. 6 to 7C . 
     Note that  FIG. 6  shows, in closeup, an area including a single metal plate  20  and an end portion  15  of a single extending portion  12  corresponding to the metal plate  20 .  FIG. 7A  shows an area including the single end portion  15  in closeup.  FIG. 7B  shows an area including a single protruding portion  22  in closeup.  FIGS. 7A and 7C  do not show a wiring  17 . 
     A voltage monitoring module  100  according to the present embodiment is different from the voltage monitoring module  100  according to the first embodiment on the following points. On other points, the voltage monitoring module  100  according to the present embodiment has a configuration similar to that of the voltage monitoring module  100  according to the first embodiment. 
     As shown in any of  FIGS. 6 to 7C , in the case of the present embodiment, multiple through-holes  24  are formed at the protruding portion  22  of each metal plate  20 . On a land  16  of the end portion  15  of each extending portion  12 , multiple non-formation areas  18  corresponding to the multiple through-holes  24  of the metal plate  20  in one-to-one correspondence are arranged. 
     That is, the multiple through-holes  24  are formed at the single metal plate  20 . Moreover, the multiple non-formation areas  18  are present on the single land  16 . 
     This can more reliably suppress the metal plate  20  from rotating (rotating in an in-plane direction of the metal plate  20 ) relative to the land  16  when the metal plate  20  is soldered to the land  16 . Thus, the more favorable accuracy of the position of the metal plate  20  with respect to the land  16  can be achieved. 
     In the present embodiment, both of the shape of the through-hole  24  and the shape of the non-formation area  18  are not specifically limited. In the example of the present embodiment, any of these shapes is a circular shape. Each through-hole  24  has a larger diameter than that of a corresponding one of the non-formation areas  18 . When viewed in a thickness direction of the metal plate  20 , each non-formation area  18  is within a corresponding one of the through-holes  24 . 
     The number of through-holes  24  at each metal plate  20  and the number of non-formation areas  18  on each land  16  may be two or three or more. In the example of the present embodiment, these numbers are two. 
     Arrangement of the multiple through-holes  24  is not specifically limited. In the example of the present embodiment, the multiple through-holes  24  are arranged at positions different from each other in a protruding direction (a down direction in  FIGS. 7B and 7C ) of the protruding portion  22 . 
     Similarly, arrangement of the multiple non-formation areas  18  is not specifically limited. In the example of the present embodiment, the multiple non-formation areas  18  are arranged at positions different from each other in the protruding direction (the down direction in  FIG. 7C ) of the protruding portion  22 . In other words, the multiple non-formation areas  18  are arranged at positions different from each other in a width direction (an up-down direction in  FIGS. 7A and 7C ) of the end portion  15 . 
     Third Embodiment 
     Next, a third embodiment will be described with reference to  FIGS. 8 to 10B . 
     Note that  FIG. 8  shows, in closeup, an area including a single metal plate  20  and an end portion  15  of a single extending portion  12  corresponding to the metal plate  20 .  FIG. 9A  shows an area including the single end portion  15  in closeup.  FIG. 9B  shows an area including a single protruding portion  22  in closeup.  FIGS. 9A and 9C  do not show a wiring  17 . 
     A voltage monitoring module  100  according to the present embodiment is different from the voltage monitoring module  100  according to the first embodiment on the following points. On other points, the voltage monitoring module  100  according to the present embodiment has a configuration similar to that of the voltage monitoring module  100  according to the first embodiment. 
     As shown in  FIGS. 8 and 9C , in the case of the present embodiment, when viewed in a thickness direction of the metal plate  20 , part of a non-formation area  18  protrudes from a through-hole  24 . 
     Such a structure is effective in, e.g., a case where there are limitations on the size of the through-hole  24 . As an example of such a case, there is a case where due to a small area (e.g., the area of the protruding portion  22 ) of the metal plate  20 , it is difficult to form, without deforming the metal plate  20 , the through-hole  24  having such a size that the through-hole  24  includes the non-formation area  18 . Moreover, this structure is also effective in a case where there are limitations on the specifications or design of the voltage monitoring module. 
     More specifically, in the case of the present embodiment, in a first direction (a right-left direction in  FIGS. 9A to 9C ) of directions along a plate surface of the metal plate  20 , the non-formation area  18  has a smaller dimension than that of the through-hole  24 . On the other hand, in a section direction (an up-down direction in  FIGS. 9A  to  9 C) perpendicular to the first direction, the through-hole  24  has a smaller dimension than that of the non-formation area  18 . 
     For example, as shown in  FIG. 9C , the non-formation area  18  is arranged at a center portion of the through-hole  24  in the first direction. In addition, in the second direction, the through-hole  24  is arranged at a center portion of the non-formation area  18 . In other words, the non-formation area  18  protrudes from the through-hole  24  in one and opposite directions in the second direction. 
     Thus, a fillet  31  is divided in two in an area viewable through the through-hole  24 . That is, in  FIGS. 9C and 9D , the fillet  31  positioned on the left side of the non-formation area  18  and the fillet  31  positioned on the right side of the non-formation area  18  are present. 
     In a case where the fillet  31  divided in two (divided in two in the first direction) with respect to the non-formation area  18  is formed as in the present embodiment, if the position of the metal plate  20  shifts from the land  16  in the first direction as shown in  FIG. 10A , the fillet  31  with a sufficient size is formed on one side (e.g., the right side in  FIGS. 10A and 10B ) of the non-formation area  18 . Thus, such a fillet  31  can be reliably recognized by inspection. 
     In the case of the present embodiment, the through-hole  24  is formed in an oval shape elongated in the first direction as shown in, e.g.,  FIG. 9B . 
     On the other hand, as shown in  FIG. 9A , the non-formation area  18  is formed in such a shape that an H-shape lies down, for example. 
     In this case, each fillet  31  has, for example, a half-moon shape if the amount of solder  30  is sufficiently great. On the other hand, each fillet  31  has, for example, a half-arc shape if the amount of solder  30  is small. 
     In the case of the present embodiment, the effect of reducing relative position shift between the land  16  and the metal plate  20  in the second direction (the direction of an arrow C shown in  FIG. 9C ) is obtained. 
     In the case of the present embodiment, a fillet  33  is, as shown in, e.g.,  FIG. 9E , formed along the through-hole  24  at a location facing the non-formation area  18  on a surface of the protruding portion  22  facing an end portion  15  side. The fillet  33  has a shape inverted from that of the fillet  31 . 
     Fourth Embodiment 
     Next, a fourth embodiment will be described with reference to  FIGS. 11 to 12D . 
     Note that  FIG. 11  shows, in closeup, an area including a single metal plate  20  and an end portion  15  of a single extending portion  12  corresponding to the metal plate  20 .  FIG. 12A  shows an area including the single end portion  15  in closeup.  FIG. 12B  shows an area including a single protruding portion  22  in closeup.  FIGS. 12A and 12C  do not show a wiring  17 . 
     A voltage monitoring module  100  according to the present embodiment is different from the voltage monitoring module  100  according to the third embodiment on the following points. On other points, the voltage monitoring module  100  according to the present embodiment has a configuration similar to that of the voltage monitoring module  100  according to the third embodiment. 
     In the case of the present embodiment, as shown in  FIG. 11  and I2C, when viewed in a thickness direction of the metal plate  20 , part of a land  16  protrudes from the outline of the metal plate  20 . 
     Thus, a fillet  34  ( FIGS. 12C and 12D ) is also formed on a portion (later-described protruding pieces  16   b ) of the land  16  protruding from the metal plate  20 . Consequently, the fillet (a fillet  31  or the fillet  34 ) can be easily reliably inspected. 
     The shape of the land  16  is not specifically limited. As the example of the present embodiment, the land  16  is formed in a shape having a rectangular main portion  16   a  and a pair of right and left protruding pieces  16   b  protruding from the main portion  16   a . Note that a non-formation area  18  is formed at the main portion  16   a . In the case of the present embodiment, the shape of the non-formation area  18  is similar to that of the third embodiment. In the case of the present embodiment, the effect of reducing relative position shift between the land  16  and the metal plate  20  in a second direction (an up-down direction in  FIG. 12C ) is also obtained. 
     As shown in  FIG. 12C , the left protruding piece  16   b  protrudes leftward of the outline of (the protruding portion  22  of) the metal plate  20 . Similarly, the right protruding piece  16   b  protrudes rightward of the outline of (the protruding portion  22  of) the metal plate  20 . The fillet  34  is formed on each protruding piece  16   b.    
     Note that as shown in  FIG. 12D , the fillet  34  is formed to the edge of the land  16 , for example. 
     Fifth Embodiment 
     Next, a fifth embodiment will be described with reference to  FIG. 13 . 
     A voltage monitoring module  100  according to the present embodiment is different from the voltage monitoring module  100  according to the first embodiment on the following points. On other points, the voltage monitoring module  100  according to the present embodiment has a configuration similar to that of the voltage monitoring module  100  according to the first embodiment. 
     In the case of the present embodiment, a flexible printed circuit board  10  has no extending portions  12 . A wiring  17  and a land  16  are arranged at a location equivalent to the body portion  11  of the first embodiment. 
     In the case of the present embodiment, a metal plate  20  is a metal tab connected to a bus bar  50 . The bus bar  50  is welded to the metal plate  20 . 
     Although not shown in  FIG. 13 , the voltage monitoring module  100  includes the multiple metal plates  20  and the multiple bus bars  50 . These multiple bus bars  50  connect multiple battery cells  70  in series. 
     Each embodiment has been described above with reference to the drawings. These embodiments are examples of the present embodiments. In the present embodiments, various configurations other than those described above can be also employed. 
     The above-described embodiments can be combined as necessary without departing from the gist of the present embodiments. For example, in a case where the through-hole  24  or the non-formation area  18  has the shape of the first embodiment, the third embodiment, or the fourth embodiment, the multiple through-holes  24  may be formed at the single metal plate  20 , and the multiple non-formation areas  18  may be present on the single land  16 . 
     The present embodiments include the following technical ideas. 
     (1) A voltage monitoring module including a flexible printed circuit board having multiple wirings and multiple lands each of which is connected to one end of the wiring and multiple metal plates arranged on the lands and soldered to the lands, a through-hole being partially formed at a location of the metal plate corresponding to the land and a non-formation area with no conductor being formed at a location of the land corresponding to part of the through-hole. 
     (2) The voltage monitoring module according to (1), in which when viewed in a thickness direction of the metal plate, the land is within the outline of the metal plate. 
     (3) The voltage monitoring module according to (1), in which when viewed in a thickness direction of the metal plate, part of the land protrudes from the outline of the metal plate. 
     (4) The voltage monitoring module according to any one of (1) to (3), in which when viewed in the thickness direction of the metal plate, the non-formation area is within the through-hole. 
     (5) The voltage monitoring module according to any one of (1) to (3), in which when viewed in the thickness direction of the metal plate, part of the non-formation area protrudes from the through-hole. 
     (6) The voltage monitoring module according to any one of (1) to (5), in which at least one of the through-hole or the non-formation area is in a non-circular shape. 
     (7) The voltage monitoring module according to any one of (1) to (6), in which the through-hole includes multiple through-holes formed at the single metal plate and the non-formation area includes multiple non-formation areas present on the single land. 
     (8) The voltage monitoring module according to any one of (1) to (7), in which the metal plate is a bus bar connecting multiple battery cells in series. 
     (9) The voltage monitoring module according to any one of (1) to (7), in which the metal plate is a metal tab connected to a bus bar. 
     The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims appended hereto.