Voltage detection wires and voltage detection wire modules

Abstract

This voltage detection line (6) is provided with: a first flexible printed board (36) which comprises a plurality of first conductive wires (42) and a first insulating film (44) that covers the plurality of first conductive wires (42); a second flexible printed board (38) which comprises a plurality of second conductive wires (46) and a second insulating film (48) that covers the plurality of second conductive wires (46); and a connection part (40) which is soldered to a first conductive wire (42) and a second conductive wire (46) corresponding to each other, thereby electrically connecting the first conductive wire (42) and the second conductive wire (46). The plurality of first conductive wires (42) and the plurality of second conductive wires (46) are electrically connected to a plurality of batteries, so that the voltages of the plurality of batteries are detected by this voltage detection line.

Description

[Technical field]

[0001] The present disclosure relates to a voltage detection line and a voltage detection line module. [Background technology]

[0002] For example, a battery module in which a plurality of batteries are electrically connected is known as a power source that requires a high output voltage for vehicles and the like. In the battery module, adjacent batteries are electrically connected via a bus bar. Also, a voltage detection line is attached to each bus bar to detect the voltage between the batteries. Regarding the voltage detection line, for example, Patent Document 1 discloses the use of a flexible printed circuit board (FPC) as the voltage detection line. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-27831 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for higher capacity battery modules, and the number of batteries arranged is increasing. This requires longer voltage detection lines. However, due to equipment restrictions, there is a limit to the length that FPCs can be manufactured, making it difficult to accommodate an increase in the number of batteries arranged.

[0005] The present disclosure has been made in light of these circumstances, and one of its objectives is to provide a technique for increasing the length of a voltage detection line made of a flexible printed circuit board. [Means for solving the problem]

[0006] One aspect of the present disclosure is a voltage detection wire that includes a first flexible printed circuit board having a plurality of first conductive wires and a first insulating film covering the plurality of first conductive wires, a second flexible printed circuit board having a plurality of second conductive wires and a second insulating film covering the plurality of second conductive wires, and connection parts soldered to the corresponding first conductive wires and second conductive wires to electrically connect the first conductive wires and the second conductive wires, and the plurality of first conductive wires and the plurality of second conductive wires are electrically connected to a plurality of batteries to detect the voltages of the plurality of batteries.

[0007] Another aspect of the present disclosure is a voltage detection line module. The voltage detection line module includes the voltage detection line of the above aspect and a support plate that supports the voltage detection line. The support plate has a protrusion, and at least one of the first flexible printed circuit board and the second flexible printed circuit board has a hole into which the protrusion fits.

[0008] Any combination of the above components and conversion of the expressions of the present disclosure between methods, devices, systems, etc. are also valid aspects of the present disclosure. Effect of the Invention

[0009] According to the present disclosure, it is possible to increase the length of a voltage detection line formed of a flexible printed circuit board. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view of a battery module including a voltage detection wire according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of a portion of a battery stack. [Diagram 3] FIG. 2 is a perspective view of a voltage detection wire according to the first embodiment. [Figure 4] FIG. 4 is a perspective view of a portion of a voltage detection line. [Diagram 5] Fig. 5(A) is a perspective view of a portion of the voltage detection line according to embodiment 2. Fig. 5(B) is a perspective view of a connection portion. [Figure 6]Fig. 6(A) is a perspective view of a portion of the voltage detection line, and Fig. 6(B) is a cross-sectional view of the connection portion. [Figure 7] Fig. 7(A) is a perspective view of a portion of a voltage detection line according to embodiment 3. Fig. 7(B) is a cross-sectional view of a connection portion. [Figure 8] FIG. 11 is a perspective view of a portion of a voltage detection wire according to a fourth embodiment. [Figure 9] FIG. 9 is a diagram illustrating an assembly process of the voltage detection line according to the fifth embodiment. [Figure 10] 10(A) and 10(B) are diagrams illustrating an assembly process of the voltage detection line according to the fifth embodiment. [Figure 11] 13 is a perspective view of a portion of a voltage detection wire and a support plate according to a sixth embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present disclosure will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, members, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and are not to be interpreted as being limiting unless otherwise specified. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are intended to distinguish one configuration from another. In addition, some of the members that are not important in explaining the embodiment in each drawing are omitted.

[0012] (Embodiment 1) Fig. 1 is a plan view of a battery module equipped with a voltage detection wire according to embodiment 1. Fig. 2 is a perspective view of a portion of a battery stack. Note that Fig. 1 illustrates only some of the batteries in the battery stack by dashed lines. Fig. 1 also illustrates only some of the conductors of the voltage detection wire by dashed lines.

[0013] The battery module 1 includes a battery stack 2, a support plate 4, and a voltage detection wire 6. The battery stack 2 includes a plurality of arranged batteries 8 and a plurality of bus bars 10 that electrically connect the batteries 8. Each battery 8 is a rechargeable secondary battery, such as a lithium ion battery, a nickel-hydrogen battery, or a nickel-cadmium battery. Each battery 8 is a so-called prismatic battery, and includes an outer can 12 that is in the shape of a flattened rectangular parallelepiped. A substantially rectangular opening (not shown) is provided on one side of the outer can 12, and an electrode body, an electrolyte, and the like are accommodated in the outer can 12 through this opening. A substantially rectangular sealing plate 14 is fitted into the opening of the outer can 12 to cover the opening.

[0014] A pair of output terminals 16 are disposed on the sealing plate 14. Specifically, the positive terminal 16a is disposed near one end in the longitudinal direction, and the negative terminal 16b is disposed near the other end. In the following, when it is not necessary to distinguish the polarities of the pair of output terminals 16, the positive terminal 16a and the negative terminal 16b will be collectively referred to as the output terminals 16.

[0015] The exterior can 12, the sealing plate 14, and the output terminal 16 are conductive and made of a metal such as aluminum, iron, or stainless steel. The exterior can 12 and the sealing plate 14 are joined by, for example, laser welding. Each output terminal 16 is inserted into a through hole formed in the sealing plate 14. An insulating seal member is interposed between each output terminal 16 and each through hole. The exterior can 12 may be covered with an insulating film (not shown) such as a shrink tube. Furthermore, the exterior can 12 and the sealing plate 14 may be made of an insulating resin.

[0016] Each battery 8 has a valve portion 18 on the sealing plate 14. The valve portion 18 is disposed between a pair of output terminals 16 on the sealing plate 14. The valve portion 18 is also called a safety valve, and is configured to open when the internal pressure of the battery 8 rises to a predetermined value or higher, thereby releasing gas inside the battery 8. The valve portion 18 is configured, for example, of a thin-walled portion that is thinner than other portions provided in a part of the sealing plate 14, and a linear groove formed on the surface of the thin-walled portion. In this configuration, when the internal pressure of the battery 8 rises, the thin-walled portion tears starting from the groove, thereby opening the valve portion 18. The valve portion 18 of each battery 8 is connected to a gas duct 20, which will be described later, and gas inside the battery is discharged from the valve portion 18 to the gas duct 20.

[0017] For convenience, in the description of this embodiment, the sealing plate 14 is defined as the upper surface of the battery 8, and the bottom surface of the exterior can 12 facing the sealing plate 14 is defined as the lower surface of the battery 8. The battery 8 also has four side surfaces connecting the upper and lower surfaces. Two of the four side surfaces are a pair of long side surfaces connected to two opposing long sides of the sealing plate 14. Each long side surface is the surface with the largest area among the surfaces of the battery 8, i.e., a main surface. The remaining two side surfaces excluding the two long side surfaces are a pair of short side surfaces connected to the short sides of the sealing plate 14.

[0018] For convenience, the surface on the upper side of the batteries 8 in the battery stack 2 is referred to as the upper surface of the battery stack 2, the surface on the lower side of the batteries 8 is referred to as the lower surface of the battery stack 2, the surface where the short sides of the batteries 8 are gathered is referred to as the long side of the battery stack 2, and the surface on the long side of the batteries 8 is referred to as the short side of the battery stack 2. These directions and positions are defined for convenience. Therefore, for example, a part defined as the upper surface in this disclosure does not necessarily mean that it is located above a part defined as the lower surface.

[0019] The multiple batteries 8 are arranged at a predetermined interval so that the main surfaces of adjacent batteries 8 face each other. In this embodiment, the batteries 8 are arranged horizontally. In the following, the direction in which the batteries 8 are arranged is referred to as a first direction X, the horizontal direction intersecting with the first direction X is referred to as a second direction Y, and the vertical direction intersecting with the first direction X and the second direction Y is referred to as a third direction Z. In this embodiment, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0020] The batteries 8 are arranged so that the output terminals 16 face the same direction. In this embodiment, the batteries 8 are arranged so that the output terminals 16 face vertically upward. When adjacent batteries 8 are connected in series, the batteries 8 are arranged so that the positive terminal 16a of one battery 8 and the negative terminal 16b of the other battery 8 are adjacent to each other. When adjacent batteries 8 are connected in parallel, the batteries 8 are arranged so that the positive terminal 16a of one battery 8 and the positive terminal 16a of the other battery 8 are adjacent to each other.

[0021] A separator (not shown) is disposed between two adjacent batteries 8. This provides electrical insulation between the two batteries 8. The separator is also called an insulating spacer, and is made of, for example, an insulating resin sheet. Examples of resins that make up the separator include polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE).

[0022] The multiple batteries 8 are sandwiched in the first direction X by a pair of end plates (not shown). The pair of end plates are adjacent to the batteries 8 located at both ends in the first direction X, with separators interposed between them. Each end plate is a metal plate made of a metal such as iron, stainless steel, or aluminum.

[0023] The multiple batteries 8 are restrained in the first direction X by a pair of restraining members (not shown). The pair of restraining members, also called bind bars, are elongated members that are long in the first direction X. The pair of restraining members are arranged, for example, in the second direction Y. Each restraining member is made of a metal such as iron or stainless steel.

[0024] The batteries 8 are sandwiched between a pair of end plates in a first direction X in a state where they are alternately arranged with the separators. The pair of restraining members are arranged to sandwich the batteries 8, the separators, and the pair of end plates in the second direction Y, and both ends of each restraining member are fixed to the pair of end plates. For example, the restraining member has bent portions at both ends in the first direction X that overlap with the main surfaces of the end plates, and these bent portions are fixed to the end plates by screws or the like. The batteries 8 are restrained in the first direction X by the pair of restraining members, and positioned in the first direction X. The separators, end plates, and restraining members have known structures, so illustrations and detailed descriptions are omitted.

[0025] The output terminals 16 of adjacent batteries 8 are electrically connected to each other by a bus bar 10. The bus bar 10 is a strip-shaped member made of a metal such as aluminum or copper. One end of the bus bar 10 is connected to the positive terminal 16a of one of two adjacent batteries 8, and the other end is connected to the negative terminal 16b of the other battery 8. The bus bar 10 may connect the output terminals 16 of the same polarity of adjacent batteries 8 in parallel to form a battery block, and further connect the battery blocks in series. An external connection terminal 22 is attached to the output terminal 16 of the outermost battery 8 in the first direction X. The external connection terminal 22 is connected to an external load (not shown).

[0026] A support plate 4 is placed on the upper surface of the battery stack 2. The support plate 4 is a plate-shaped member that supports the voltage detection wires 6. The support plate 4 and the voltage detection wires 6 together constitute a voltage detection wire module 7.

[0027] The support plate 4 covers the upper surface of the battery stack 2, i.e., the surface on which the valve portions 18 of each battery 8 are disposed. The support plate 4 has a base plate 24, a plurality of openings 26, and a gas duct 20. The base plate 24 extends along the upper surface of the battery stack 2. The multiple openings 26 and the gas duct 20 are provided in the base plate 24.

[0028] The multiple openings 26 are provided at positions overlapping with the output terminals 16 of each battery 8 in the third direction Z, and expose the output terminals 16. A bus bar 10 is placed in each opening 26. The multiple bus bars 10 are supported by the support plate 4. Therefore, the support plate 4 also functions as a so-called bus bar plate.

[0029] The gas duct 20 is a flow path into which gas ejected from each battery 8 flows. The base plate 24 has a plurality of openings (not shown) that expose the valve portions 18 at positions corresponding to the valve portions 18 of each battery 8. The gas duct 20 extends in the first direction X and overlaps with each valve portion 18 in the third direction Z. Each valve portion 18 is connected to the gas duct 20 via an opening provided in the base plate 24. The gas ejected from each battery 8 is temporarily stored in the gas duct 20. Therefore, the support plate 4 also functions as a so-called duct plate.

[0030] The support plate 4 in this embodiment is made of resin such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), Noryl (registered trademark) resin (modified PPE), etc., except for the top surface facing each valve portion 18 in the gas duct 20. The top surface of the gas duct 20 is made of a metal plate such as iron or aluminum.

[0031] The voltage detection wire 6 is a member for detecting the voltage of the plurality of batteries 8. The voltage detection wire 6 is electrically connected to the plurality of bus bars 10 to detect the voltage of each battery 8. The voltage detection wire 6 has a plurality of conductors 28 and an insulating film 30 that covers the plurality of conductors 28. One end of each conductor 28 is electrically connected to the corresponding bus bar 10 via a tab terminal portion 32. The conductor 28 is joined to one end of the tab terminal portion 32 by, for example, soldering. The other end of the tab terminal portion 32 is joined to the bus bar 10 by, for example, laser welding or ultrasonic bonding. The other end of each conductor 28 is connected to a connector 34. This electrically connects each bus bar 10 to the connector 34. Some of the conductors 28 electrically connect the external connection terminal 22 to the connector 34. The connector 34 is connected to an external battery ECU or the like. The battery ECU controls detection of the voltage of each battery 8 and charging / discharging of each battery 8. The conductor wire 28 may be connected directly to the bus bar 10 without going through the tab terminal portion 32 .

[0032] Fig. 3 is a perspective view of the voltage detection line 6 according to the first embodiment. Fig. 4 is a perspective view of a portion of the voltage detection line 6. Note that Fig. 3 and Fig. 4 show the flexible printed circuit boards in a schematic manner, and the manner in which each flexible printed circuit board extends, the branch shape, and the like are not particularly limited.

[0033] The voltage detection line 6 includes a first flexible printed circuit board 36, a second flexible printed circuit board 38, and a connection portion 40. One end of the first flexible printed circuit board 36 is connected to the connector 34. The other end of the first flexible printed circuit board 36 is connected to the second flexible printed circuit board 38 via the connection portion 40. The voltage detection line 6 may have a structure in which three or more flexible printed circuit boards are connected together via the connection portion 40.

[0034] The first flexible printed circuit board 36 has a plurality of first conductive wires 42 and a first insulating film 44. The plurality of first conductive wires 42 are covered with the first insulating film 44. The second flexible printed circuit board 38 has a plurality of second conductive wires 46 and a second insulating film 48. The plurality of second conductive wires 46 are covered with the second insulating film 48. The plurality of first conductive wires 42 and the plurality of second conductive wires 46 form the conductive wire 28, and the first insulating film 44 and the second insulating film 48 form the insulating film 30. The first conductive wires 42 and the second conductive wire 46 are made of a metal such as copper. The first insulating film 44 and the second insulating film 48 are made of a resin such as polyimide (PI) or polyethylene naphthalate (PEN).

[0035] The connection portion 40 is soldered to each of the first conducting wires 42 and the second conducting wires 46 corresponding to each other. This electrically connects the first conducting wires 42 and the second conducting wires 46. The connection portion 40 of this embodiment has a plurality of metal members 50 soldered to each of the first conducting wires 42 and each of the second conducting wires 46. Each metal member 50 is formed of a single metal piece. Each metal member 50 is strip-shaped, and one end is soldered to the first conducting wire 42 and the other end is soldered to the second conducting wire 46.

[0036] One end of each of the first conducting wires 42 is connected to the connector 34. The other ends of some of the first conducting wires 42 are connected to the bus bar 10 via the tab terminal portion 32. The other ends of some of the first conducting wires 42 are soldered to the metal member 50 of the connection portion 40. One end of each of the second conducting wires 46 is soldered to the metal member 50. The other end of each of the second conducting wires 46 is connected to the bus bar 10 via the tab terminal portion 32. In this way, the multiple first conducting wires 42 and the multiple second conducting wires 46 are electrically connected to the multiple batteries 8.

[0037] A cutout portion 52 is provided in the first insulating film 44 in a region sandwiched between adjacent metal members 50. Similarly, a cutout portion 54 is provided in the second insulating film 48 in a region sandwiched between adjacent metal members 50. This makes it possible to increase the creepage distance between adjacent metal members 50, thereby improving the insulation between adjacent conductive wires 28.

[0038] An adhesive may be interposed between each of the first conductive wires 42 and the connection portion 40, and between each of the second conductive wires 46 and the connection portion 40. This can increase the connection strength between each of the conductive wires and the connection portion 40.

[0039] As described above, the voltage detection wire 6 according to this embodiment includes the first flexible printed circuit board 36 having a plurality of first conducting wires 42 and a first insulating film 44 covering the plurality of first conducting wires 42, the second flexible printed circuit board 38 having a plurality of second conducting wires 46 and a second insulating film 48 covering the plurality of second conducting wires 46, and the connection parts 40 soldered to the corresponding first conducting wires 42 and second conducting wires 46, respectively, to electrically connect the first conducting wires 42 and the second conducting wires 46. The voltage detection wire 6 has the plurality of first conducting wires 42 and the plurality of second conducting wires 46 electrically connected to the plurality of batteries 8, and detects the voltage of the plurality of batteries 8.

[0040] In the present embodiment, the first flexible printed circuit board 36 and the second flexible printed circuit board 38 are connected to each other at a connection portion 40. This makes it possible to lengthen the voltage detection line 6 made of the flexible printed circuit board without increasing the size of the manufacturing equipment for the flexible printed circuit board.

[0041] Moreover, the connection portion 40 is soldered to the first conducting wire 42 and the second conducting wire 46. Therefore, the connection strength of the first conducting wire 42 and the second conducting wire 46 can be increased compared to the connection using anisotropic conductive film (ACF) or a ZIF connector, which is a conventional method for connecting flexible printed circuit boards. In addition, the intrusion of foreign matter into the joint can be suppressed, and the stability of the electrical connection between the first conducting wire 42 and the second conducting wire 46 can be increased. Therefore, the voltage detection wire 6 can be made longer while maintaining its reliability. In addition, the voltage detection wire 6 is suitable for an in-vehicle battery module 1 that is prone to external vibrations and impacts. As a result, the safety of the battery module 1 in which the voltage detection wire 6 is mounted can be further improved.

[0042] Moreover, the connection portion 40 of the present embodiment has a plurality of metal members 50 soldered to each of the first conducting wires 42 and each of the second conducting wires 46. Each of the metal members 50 is formed from a single metal piece. This makes it possible to connect the first flexible printed circuit board 36 and the second flexible printed circuit board 38 with a simple structure.

[0043] (Embodiment 2) Except for the structure of the connection portion 40, the second embodiment has a common configuration with the first embodiment. Hereinafter, the present embodiment will be described focusing on the configuration different from the first embodiment, and the common configuration will be briefly described or omitted. FIG. 5(A) is a perspective view of a part of the voltage detection line 6 according to the second embodiment. FIG. 5(B) is a perspective view of the connection portion 40. FIG. 6(A) is a perspective view of a part of the voltage detection line 6. FIG. 6(B) is a cross-sectional view of the connection portion 40. FIGS. 5(A) and 5(B) show a state in which the first flexible printed circuit board 36 and the second flexible printed circuit board 38 are separated. FIGS. 6(A) and 6(B) show a state in which the first flexible printed circuit board 36 and the second flexible printed circuit board 38 are connected.

[0044] The voltage detection line 6 includes a first flexible printed circuit board 36, a second flexible printed circuit board 38, and a connection portion 40. The connection portion 40 is soldered to the corresponding first conductive wire 42 and second conductive wire 46, respectively. This electrically connects the first conductive wire 42 and the second conductive wire 46.

[0045] The connection portion 40 has a plurality of metal members 50 soldered to each of the first conducting wires 42 and each of the second conducting wires 46. In this embodiment, each metal member 50 has a structure divided into a first portion 56 soldered to the first conducting wire 42 and a second portion 58 soldered to the second conducting wire 46. The first portion 56 and the second portion 58 are fitted together, thereby electrically connecting the first conducting wire 42 and the second conducting wire 46. Therefore, the first portion 56 and the second portion 58 constitute a pair of connection terminals that are connected to each other.

[0046] As an example, the first part 56 is a flat frame-shaped body, and defines an insertion hole 60 extending in the extension direction of the first conductive wire 42. A protrusion 62 protruding toward the center of the insertion hole 60 is provided at a predetermined position in the insertion hole 60. The second part 58 is a flat plate having a shape corresponding to the insertion hole 60, and has a recess 64 on its main surface having a shape corresponding to the protrusion 62. The second part 58 is press-fitted into the insertion hole 60 of the first part 56. When the second part 58 advances to a predetermined position in the insertion hole 60, the protrusion 62 fits into the recess 64. This causes the first part 56 and the second part 58 to fit together. Note that the first part 56 may be a flat plate, and the second part 58 may be a frame-shaped body.

[0047] In the present embodiment, the first portion 56 is directly soldered to the first conducting wire 42, and the second portion 58 is directly soldered to the second conducting wire 46, so that the first portion 56 and the second portion 58 are fitted together. This can increase the connection strength between the first conducting wire 42 and the second conducting wire 46, and can increase the stability of the electrical connection between the first conducting wire 42 and the second conducting wire 46. Therefore, the voltage detection wire 6 can be made longer while maintaining its reliability.

[0048] (Embodiment 3) Except for the structure of the connection portion 40, the third embodiment has a common configuration with the first embodiment. The following description of the third embodiment will focus on the configuration that differs from the first embodiment, and the common configuration will be explained briefly or omitted. FIG. 7(A) is a perspective view of a portion of the voltage detection wire 6 according to the third embodiment. FIG. 7(B) is a cross-sectional view of the connection portion 40.

[0049] The voltage detection line 6 includes a first flexible printed circuit board 36, a second flexible printed circuit board 38, and a connection portion 40. The connection portion 40 is soldered to the first conductive wire 42 and the second conductive wire 46, which correspond to each other. This electrically connects the first conductive wire 42 and the second conductive wire 46. The connection portion 40 of this embodiment has a plurality of metal members 50 soldered to each of the first conductive wires 42 and each of the second conductive wires 46. Each metal member 50 is formed of a single metal piece as in the first embodiment. Note that each metal member 50 may be divided into a first portion 56 and a second portion 58 as in the second embodiment.

[0050] The connection portion 40 of this embodiment has a plate portion 66 that supports the multiple metal members 50. The plate portion 66 is a flat plate made of insulating resin or the like, and is interposed between the multiple metal members 50 and the support plate 4. This makes it possible to extend the creepage distance between the outside and each metal member 50. This makes it possible to improve the insulation of the connection portion 40, and further improve the reliability of the voltage detection line 6. The plate portion 66 may be formed of a part of the support plate 4.

[0051] Moreover, the connection portion 40 of the present embodiment has a wall portion 68 that separates the adjacent metal members 50. The wall portion 68 is made of an insulating resin or the like. The wall portion 68 is fitted into the cutout portion 52 and the cutout portion 54, for example. By providing the wall portion 68, the creepage distance between the adjacent metal members 50 can be extended. Therefore, the insulation of the connection portion 40 can be improved.

[0052] In the present embodiment, the plate portion 66 and the multiple wall portions 68 are integrally formed. This makes it possible to prevent an increase in the number of parts of the voltage detection line 6. Also, it is possible to prevent the assembly work of the voltage detection line 6 from becoming complicated.

[0053] (Embodiment 4) The fourth embodiment has a common configuration with the first embodiment, except for the structure of the connection portion 40. The following description of the present embodiment will focus on the configuration different from the first embodiment, and the common configuration will be explained briefly or omitted. Fig. 8 is a perspective view of a part of the voltage detection wire 6 according to the fourth embodiment.

[0054] The voltage detection line 6 includes a first flexible printed circuit board 36, a second flexible printed circuit board 38, and a connection portion 40. The connection portion 40 is soldered to the first conductive wire 42 and the second conductive wire 46, which correspond to each other. This electrically connects the first conductive wire 42 and the second conductive wire 46. The connection portion 40 has a plurality of metal members 50 soldered to each of the first conductive wires 42 and each of the second conductive wires 46. Each metal member 50 in this embodiment has a structure divided into a first portion 56 and a second portion 58 as in the second embodiment. Each metal member 50 may be composed of a single metal piece as in the first embodiment.

[0055] The connection portion 40 of the present embodiment has a sealing resin layer 70 that seals the joint with the first conductive wire 42 and the joint with the second conductive wire 46. The sealing resin layer 70 is made of a resin such as phenol, acrylic, epoxy, silicone, polyolefin, urethane, or silyl acrylate. By covering the joint between each conductive wire and the connection portion 40 with the sealing resin layer 70, the connection strength between each conductive wire and the connection portion 40 can be increased. Furthermore, the insulation of the connection portion 40 can be improved.

[0056] (Embodiment 5) The fifth embodiment has a common configuration with the first embodiment, except for the structure of the connection portion 40. The following description of the present embodiment will focus on the configuration different from the first embodiment, and the common configuration will be briefly described or omitted. Figures 9, 10(A) and 10(B) are diagrams showing an assembly process of the voltage detection line 6 according to the fifth embodiment.

[0057] The voltage detection line 6 includes a first flexible printed circuit board 36, a second flexible printed circuit board 38, and a connection portion 40. The connection portion 40 has a plurality of metal members 50 soldered to each of the first conducting wires 42 and each of the second conducting wires 46. Each of the metal members 50 is formed of a single metal piece as in the first embodiment. The connection portion 40 also has a plate portion 66 as in the third embodiment. Each of the metal members 50 is fixed to one main surface of the plate portion 66.

[0058] The first insulating film 44 of the present embodiment has a wide portion 72 at the end on the connection portion 40 side. The wide portion 72 spreads in a direction intersecting with the extending direction of the first conducting wire 42. The width of the wide portion 72 in the intersecting direction is wider than the plate portion 66, for example, about twice as wide as the plate portion 66.

[0059] 9, first, the second conductive wire 46 of the second flexible printed circuit board 38 is soldered to the metal member 50. Next, the first conductive wire 42 of the first flexible printed circuit board 36 is soldered to the metal member 50. As a result, the first flexible printed circuit board 36 and the second insulating film 48 are connected by the connection portion 40, as shown in FIG. 10(A). In this state, the main surface of the plate portion 66 to which the metal member 50 is fixed is covered with a first region 72a corresponding to approximately half of the wide portion 72. Then, a second region 72b corresponding to the remaining half of the wide portion 72 is folded back along the folding line L.

[0060] As a result, as shown in FIG. 10(B), the main surface on the opposite side of the plate portion 66 is covered with the second region 72b. That is, the connection portion 40 is wrapped in the wide portion 72. By heating the wide portion 72 in this state, the wide portion 72 is thermally welded to the connection portion 40. This can increase the connection strength between each conductor and the connection portion 40. Also, the insulation of the connection portion 40 can be improved. The connection portion 40 does not need to have the plate portion 66. Also, the metal member 50 may be composed of a first portion 56 and a second portion 58.

[0061] (Embodiment 6) The sixth embodiment has a common configuration with the first embodiment, except for the structures of the support plate 4 and the voltage detection wire 6. The following description of the sixth embodiment will focus on the configurations that are different from the first embodiment, and the common configurations will be explained briefly or omitted. Fig. 11 is a perspective view of a portion of the voltage detection wire 6 and the support plate 4 according to the sixth embodiment.

[0062] The voltage detection line 6 includes a first flexible printed circuit board 36, a second flexible printed circuit board 38, and a connection portion 40. The connection portion 40 is soldered to the first conductive wire 42 and the second conductive wire 46, which correspond to each other. This electrically connects the first conductive wire 42 and the second conductive wire 46. The connection portion 40 has a plurality of metal members 50 soldered to each of the first conductive wires 42 and each of the second conductive wires 46. Each metal member 50 in this embodiment has a structure divided into a first portion 56 and a second portion 58 as in the second embodiment. Each metal member 50 may be composed of a single metal piece as in the first embodiment.

[0063] The support plate 4 has a protrusion 74 in an area where the voltage detection wire 6 is placed. The protrusion 74 protrudes toward the voltage detection wire 6. The protrusion 74 is provided in an area where the first flexible printed circuit board 36 overlaps and an area where the second flexible printed circuit board 38 overlaps. Moreover, the protrusion 74 is preferably disposed near the area where the connection portion 40 overlaps.

[0064] The first flexible printed circuit board 36 and the second flexible printed circuit board 38 each have a hole 76. The hole 76 has a shape corresponding to the protrusion 74, and is provided at a position where the hole 76 overlaps with the protrusion 74.

[0065] The voltage detection wire 6 is placed on the support plate 4 with the projection 74 and the hole 76 aligned to overlap. As a result, the projection 74 fits into the hole 76, and the voltage detection wire 6 is positioned relative to the support plate 4. As a result, stress on the connection portion 40 can be suppressed when the battery module 1 vibrates or receives an impact. This makes it possible to lengthen the voltage detection wire 6 while maintaining its reliability. Note that if at least one of the first flexible printed circuit board 36 and the second flexible printed circuit board 38 has the hole 76, the connection reliability between the first flexible printed circuit board 36 and the second flexible printed circuit board 38 can be improved to some extent.

[0066] The above describes the embodiments of the present disclosure in detail. The above-mentioned embodiments merely show specific examples of implementing the present disclosure. The contents of the embodiments do not limit the technical scope of the present disclosure, and many design changes such as changes, additions, and deletions of components are possible within the scope of the idea of ​​the present disclosure defined in the claims. A new embodiment with design changes has the effects of the combined embodiments and modifications. In the above-mentioned embodiments, the contents for which such design changes are possible are emphasized by adding notations such as "in this embodiment" and "in this embodiment", but design changes are permitted even in contents without such notations. Any combination of components included in the embodiments is also valid as an aspect of the present disclosure.

[0067] There is no particular limit to the number of batteries 8 included in the battery module 1. There is no particular limit to the structure of each part of the battery stack 2, including the structure for restraining the multiple batteries 8. The batteries 8 may be cylindrical, for example.

[0068] The embodiment may be specified by the items described below. [Item 1] A plurality of batteries (8); a voltage detection line (6) electrically connected to the plurality of batteries (8) for detecting the voltage of the plurality of batteries (8); The voltage detection wire (6) a first flexible printed circuit board (36) having a plurality of first conductive wires (42) and a first insulating film (44) covering the plurality of first conductive wires (42); a second flexible printed circuit board (38) having a plurality of second conductive wires (46) and a second insulating film (48) covering the plurality of second conductive wires (46); A battery module (1) comprising: a connection portion (40) soldered to each of the corresponding first conductive wires (42) and second conductive wires (46) to electrically connect the first conductive wires (42) and second conductive wires (46). [Explanation of symbols]

[0069] 4 Support plate, 6 Voltage detection wire, 7 Voltage detection wire module, 8 Battery, 36 First flexible printed circuit board, 38 Second flexible printed circuit board, 40 Connection portion, 42 First conducting wire, 44 First insulating film, 46 Second conducting wire, 48 Second insulating film, 50 Metal member, 56 First portion, 58 Second portion, 66 Plate portion, 68 Wall portion, 70 Sealing resin layer, 72 Wide portion, 74 Protrusion portion, 76 Hole portion.

Claims

1. a first flexible printed circuit board having a plurality of first conductive wires and a first insulating film covering the plurality of first conductive wires; a second flexible printed circuit board having a plurality of second conductive wires and a second insulating film covering the plurality of second conductive wires; a connection portion that is soldered to each of the first conducting wires and the second conducting wires corresponding to each other to electrically connect the first conducting wires and the second conducting wires, the first conductive wires and the second conductive wires are electrically connected to a plurality of batteries to detect voltages of the plurality of batteries; the connection portion includes a plurality of metal members soldered to each of the first conducting wires and each of the second conducting wires; the first insulating film and the second insulating film have cutouts in areas between the adjacent metal members, the connection portion includes a plate portion supporting the plurality of metal members and a wall portion separating adjacent ones of the metal members, The plate portion and the wall portion are integrally formed, The wall portion is fitted into the cutout portion. Voltage detection wire.

2. 2. The voltage detection wire according to claim 1, wherein each metal member is formed of a single metal piece.

3. each metal member has a structure divided into a first portion soldered to the first conducting wire and a second portion soldered to the second conducting wire; The voltage detection wire according to claim 1 , wherein the first portion and the second portion are fitted together to electrically connect the first conducting wire and the second conducting wire.

4. The voltage detection wire according to claim 1 , wherein the connection portion has a sealing resin layer that seals a joint portion with the first conducting wire and a joint portion with the second conducting wire.

5. the first insulating film has a wide portion at an end portion on a connection portion side, The voltage detection wire according to claim 1 , wherein the connection portion is surrounded by the wide portion.

6. A voltage detection line according to any one of claims 1 to 5; a support plate for supporting the voltage detection line; The support plate has a protrusion, At least one of the first flexible printed circuit board and the second flexible printed circuit board has a hole into which the protrusion fits.

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