JPH10313151A - Flexible board with various metal conductor path - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible board which is enhanced in connection reliability, so as to enable a desired current to flow safely. SOLUTION: Power metal conductor paths 12 to 16, formed of nickel thin plate and control metal conductor paths 20 to 24 formed of copper foil subjected to etching, are formed on an insulating flexible board 11. The power metal conductor paths 12 and 14 are partly projected from the insulating flexible board 11. The tips of 12a and 14a of the projecting parts of the conductor paths 12 and 14 are spot-welded to the electrodes of a lithium ion cell. Power supply terminals 30 and 31 made of phosphor bronze thin plate are soldered to the one end of the power metal conductor paths 13 and 16. A voltage detection circuit, is connected to the control metal conductor paths 20 and 23 by soldering, an overdischarge prevention circuit 33 and an overcharge prevention circuit 34 are connected to the control metal conductor paths 21 and 22 by soldering respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible substrate having a plurality of types of metal conductor paths, and more particularly to a flexible substrate suitable for a power supply circuit attached to a lithium ion battery.

[0002]

2. Description of the Related Art A lithium ion battery has a large electric power,
In addition, a flexible substrate provided with a charge / discharge protection circuit is used because of its ignitability. A plurality of metal conductor paths using copper foil are formed on one or both sides of the flexible substrate. These metal tracks can be divided into power metal tracks and control metal tracks.

[0003] The power metal conductor path is for passing a large current from a lithium ion battery, and is made of a wide copper foil. Further, an overdischarge prevention circuit, an overcharge prevention circuit, a temperature fuse, and the like are connected in the power metal conductor path.

[0004] The control metal conductor path is for passing a small current, and is made of a narrow linear copper foil. This control metal conductor path connects the voltage detection circuit to the power metal conductor path, connects the overdischarge prevention circuit and the overcharge prevention circuit to the voltage detection circuit, and removes resistors and capacitors from each circuit. Used to attach.

[0005] An electrode connection terminal is soldered to one end of the power metal conductor path. This electrode connection terminal is spot-welded to the electrode of the lithium ion battery, and is firmly joined to the electrode. As the electrode connection terminal, a punched nickel thin plate is used because of ease of spot welding and ease of flowing a large current.

A power supply terminal is soldered to the other end of the power metal conductor path. For example, an elastic phosphor bronze thin plate is used as the power supply terminal in order to make good contact with a contact pin in the electronic camera when a lithium ion battery is loaded in the electronic camera.

On the other hand, a nickel-cadmium battery, a nickel-metal hydride battery, or the like does not require a control circuit such as an over-discharge prevention circuit and an over-charge prevention circuit because there is little danger in charging and discharging. In such a battery, a flexible substrate in which both surfaces of a punched nickel thin plate are laminated with an insulating film is used.

[0008]

However, the above-mentioned flexible board has a problem that a large current cannot flow through the power metal conductor path of the copper foil.

Nickel is used for an electrode of a lithium ion battery. However, since an oxide film is easily formed on nickel, nickel is used to solder the electrode of the lithium ion battery to a power metal conductive path of copper foil. In this case, it is not possible to obtain a bonding strength strong enough to hold the lithium ion battery by the oxide film. In addition, there is a problem that a large amount of flux for reducing the oxide film is required, and the soldering operation is difficult. Further, the solder may be melted by heat generated during use of the lithium ion battery. Therefore, in order to secure the connection between the flexible substrate and the electrode, the battery connection terminal of the nickel thin plate was used conventionally,
One end is spot welded to the electrode and the other end is soldered to a copper metal power conductor track. However, even in this case, in addition to the problem that the number of steps is increased due to the use of the battery connection terminal, there is a problem in the reliability of the joining because the soldering is performed to the power metal conductor path.

[0010] The thermal fuse is connected to the power metal conductor path by soldering. However, there is a problem that the thermal fuse is partially broken or completely blown by the heat during the soldering operation. Although the thermal fuse is packaged in a tube, it is invisible in the case of a semi-broken state, so that an inconvenience such as requiring an inspection process is caused.

On the other hand, in a flexible substrate using a nickel thin plate as a metal conductor path, there is a problem that a fine wiring pattern cannot be formed because the stamped metal conductor path is bonded to an insulating substrate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flexible substrate using an optimum metal material for each metal conductor path in consideration of the use of the metal conductor paths and problems in bonding.

Another object of the present invention is to provide a flexible substrate which allows a large current to flow through a power metal conductor path and enables fine wiring to a control metal conductor path. It is intended for.

Still another object of the present invention is to provide a flexible substrate capable of spot welding a part of a power metal conductive path directly to a lithium ion battery.

[0015]

According to a first aspect of the present invention, there is provided a flexible printed circuit board comprising at least a first metal material, a first metal material, and a first metal material. And a metal conductor path made of a second metal material formed on an insulating substrate.

According to a second aspect of the present invention, there is provided a flexible substrate having at least a first insulating substrate having a metal conductor path formed of a first metal material and a second insulating substrate having at least a metal conductor path formed of a second metal material. And an insulating substrate, which is bonded to the insulating substrate to form a laminated structure.

According to a third aspect of the present invention, in the flexible substrate, a nickel thin plate is used as the first metal material, and a copper foil is used as the second metal material.

According to a fourth aspect of the present invention, there is provided a flexible substrate in which a power metal conductive path made of a first metal material and a control metal conductive path made of a second metal material are formed on an insulating substrate.

In the flexible substrate according to the fifth aspect, a thin metal plate is used as the first metal material, and a copper foil is used as the second metal material.

According to a sixth aspect of the present invention, there is provided a flexible substrate in which a power metal conductor path and a control metal conductor path are formed on one surface of an insulating substrate.

According to a seventh aspect of the present invention, there is provided a flexible substrate in which a power metal conductive path is formed on one side of an insulating substrate and a control metal conductive path is formed on another side.

In the flexible substrate according to the present invention, a nickel thin plate is used as the first metal material.

In the flexible substrate according to the ninth aspect, a lithium ion battery is connected to one end of the power metal conductor path,
The control circuit is connected to one end of the control metal conductor path.

[0024]

FIG. 1 shows a flexible substrate used as a power supply circuit of a lithium ion battery. The flexible substrate 10 includes an insulating substrate 11 having flexibility. As the insulating substrate 11, for example, a polyimide film is used. A plurality of hatched power metal conductor paths 12 to 16 and a plurality of control metal conductor paths 20 to 24 are formed on the insulating substrate 11.

The power metal conductor paths 12 to 16 are used to pass a large current (for example, several A) from the lithium ion battery. On the other hand, the control metal conductor paths 20 to 24
It is used to flow a small current (for example, several tens mA) sufficient to control an IC device. Therefore, as the power metal conductor paths 12 to 16, it is easy to pass a large current,
In addition, a metal material that can be spot-welded with a strong bonding force is used. The control metal conductor paths 20 to 24 may have a small current, but use a metal material capable of forming a fine pattern.

In this embodiment, the power metal conductor path 12
As ~ 16, for example, a thickness of 0.1 mm and a width of 5 mm
To this extent, nickel sheets are used. This nickel thin plate is stamped from a plate material into a shape conforming to the pattern, and is adhered to the insulating substrate 11 by an adhesive 26 as shown in FIG.

As the control metal conductor paths 20 to 24, for example, a copper foil having a thickness of about 0.05 mm and a width of about 0.5 to 1 mm is used. This is because the sheet-like copper foil is
It is manufactured by bonding to the insulating substrate 11 with an etching process 7 and then etching.

One end 12a of the power metal conductor path 12 protrudes from the insulating substrate 11, and is connected to the positive terminal of the lithium ion battery.
It is firmly joined to the electrode by spot welding. Similarly, one end 14a of the power metal conductor path 14 also protrudes from the insulating substrate 11, and is spot-welded to the negative electrode of the lithium ion battery.

At one end of the power metal conductor paths 13 and 16,
L-shaped power terminals 30, 31 are soldered. The power supply terminals 30 and 31 are made of an elastic phosphor bronze thin plate in order to increase the contact pressure with a contact pin (not shown). Note that, of the power supply terminals 30 and 31, the surfaces that contact the power metal conductor paths 13 and 16 may be elongated, and the power metal conductor paths 13 and 16 may be shortened accordingly. After bonding the power supply terminals 30 and 31 to the insulating substrate 11 with an adhesive, the power metal conductor paths 13 and 16 are connected to the power metal conductor paths 13 and 16 by soldering or the like. In this case, a copper foil, a nickel thin plate,
Three types of metal conductor tracks of phosphor bronze sheet will be formed.

Temperature fuses 32 are spot-welded to the power metal conductor paths 12 and 13. The thermal fuse 32 is formed by packaging the fuse in a transparent plastic tube. The temperature fuse 32 is configured to detect abnormal heat generation of the lithium ion battery when the lithium ion battery is charged or discharged, and to blow the fuse.

An overdischarge prevention circuit 33 is connected to the power metal conductor paths 14 and 15, and the power metal conductor paths 15, 1
6 is connected to an overcharge prevention circuit 34. The control terminals of the overdischarge prevention circuit 33 and the overcharge prevention circuit 34 are connected to the voltage detection circuit 35 via the control metal conductor paths 21 and 22, respectively. This voltage detection circuit 35
Are connected to the power metal conductor paths 12, 14 via the control metal conductor paths 20, 23.

Overdischarge prevention circuit 33, overcharge prevention circuit 3
4. The voltage detection circuit 35 is packaged. The capacitor 3 is connected to the overdischarge prevention circuit 33 and the voltage detection circuit 35 via the control metal conductor paths 24 and 23.
6, 37 are connected. The voltage detection circuit 35
Has an IC device having a large number of pins, but these pins and control metal conductor paths are omitted for simplification of the drawing.

When the charging voltage reaches the upper limit value during charging of the lithium ion battery, the voltage detection circuit 35 detects this and sends a control signal to the overcharge prevention circuit 34. The overcharge prevention circuit 34 includes a switching element connected to the power metal conductor paths 14 and 15, and turns off the switching element according to a control signal.

When the discharge voltage reaches the lower limit during discharging of the lithium ion battery, the voltage detection circuit 35 detects this and sends a control signal to the overdischarge prevention circuit 33. The overdischarge prevention circuit 33 includes a switching element connected to the power metal conductor paths 15 and 16, and turns off the switching element according to a control signal.

As shown in FIG. 2, for example, the power metal conductor path 12 and the control metal conductor path 20 are connected via solder 40. Further, in order to prevent electric shock and short circuit, an insulating film 41 is adhered on the insulating substrate 11 via an adhesive 42 to cover each metal conductor path. Further, instead of the film 41, a magnetic shield sheet for blocking electromagnetic waves may be used.

Next, an example of manufacturing the flexible substrate 10 will be briefly described. A polyimide film is used as the insulating substrate 11, and a copper foil is adhered to one surface of the polyimide film.
Unnecessary copper foil is removed by a known etching process to form the control metal conductor paths 20 to 24. By using this etching process, the control metal conductor paths 20 to 24 having a fine shape can be manufactured. When forming the control metal conductor paths on both sides of the insulating substrate 11, copper foil is adhered on both sides, and films are laminated on both sides.

The nickel sheet material is set in a press machine, and the power metal conductor paths 12 to 16 are punched. These power metal conductor paths 12 to 16 are bonded at predetermined positions on the insulating substrate 11. Here, instead of individually fabricating the power metal conductor paths 12 to 16, all the power metal conductor paths 12 to 16 are carried out as in the manufacture of a lead frame.
Is provided at the end, and the rib is cut off after bonding to the insulating substrate 11, thereby simplifying the manufacturing.

The power metal conductor paths 12 to 16 and the control metal conductor paths 20 to 24 are connected. This connection method includes:
There are soldering and jumper wires. For soldering,
As shown in FIG. 2, for example, solder 40 is piled on the boundary between the power metal conductor path 12 and the control metal conductor path 20 to connect the two.

FIG. 3 shows a connection state by a jumper wire, and the power metal conductor track 12 and the control metal conductor track 20 are connected by a jumper wire 44. In FIG. 3, the film for lamination is omitted.

Also, a hot melt is used as an adhesive for the power metal conductor path, and solder is previously held at a portion connected to the control metal conductor path, and the portion where the solder is piled is used as the control metal conductor path. In a state of being overlapped on the insulating substrate 11 and pressing a heater from above the power metal conductor path,
Soldering and bonding may be performed simultaneously.

Next, a polyimide film 41 is laminated on the insulating substrate 11. In this film 41,
Power metal tracks 12-16 and control metal tracks 20
Holes are formed at locations corresponding to the connection portions of the power metal conductor path 1 except for these connection portions.
The exposed surfaces of 2 to 16 and the control metal conductor paths 20 to 24 are covered with the film 41 to be insulated.

Each electronic component such as the voltage detection circuit 35 is mounted on the insulating substrate 11. Among these electronic components, the thermal fuse is connected by sbot welding, and the other components are connected by solder.

The package of the lithium ion battery will be described with reference to FIG. In FIG. 1, a thick insulating sheet 46 is adhered to a substantially semicircular portion at the right end of the flexible substrate 10 to insulate a connection portion of the voltage detection circuit 35 and the like. When the control metal conductor path is formed on the back surface of the flexible substrate 10, the insulating sheet 47 is also adhered to the back surface.

Next, the flexible substrate 10 is overlaid on the lithium ion battery 48. After bending a part of the power metal conductor path 12 protruding from the insulating substrate 11, one end 12 a is spot-welded to the + electrode of the lithium ion battery 48. Similarly, after partially bending the power metal conductor path 14, one end 14a is spot-welded to the negative electrode. In FIG. 1, a substantially semicircular portion at the right end is bent from the line 49, and this portion is pressed against the negative electrode of the lithium ion battery 48.

The lithium ion battery 48 to which the flexible board 10 is attached is put in the case body 50. In this state, the power supply terminal 30 faces the opening 50a and the opening 50b
Faces the power supply terminal 31. Finally, the lid 51 is put on the case main body 50 to complete the lithium ion battery pack.

FIG. 5 shows a flexible substrate in which two types of metal conductor paths are provided separately on one side of an insulating substrate. On the upper surface of the flexible insulating substrate 54, a power metal conductor path 56 using a thin metal plate is provided via an adhesive 55.
Is glued. Further, a control metal conductor path 58 of a metal thin film is adhered to the lower surface of the insulating substrate 54 via an adhesive 57. In order to connect these metal conductor paths 56, 58, a through hole 59 is formed in the insulating substrate 54 and each metal conductor path 56, 58. Solder 60 is injected into the through hole 59. In place of the solder 60, the through hole 59 may be plated with metal, for example, copper.

FIG. 6 shows a flexible substrate having a laminated structure. A plurality of power metal conductor paths 66 to 69 are formed on the upper surface of the insulating substrate 65. The power metal conductor paths 66 and 67 are made of a nickel thin plate, and one end of each is spot-welded to a lithium ion battery. Phosphor bronze sheets are used as the power metal conductor paths 68 and 69. Reference numeral 70 denotes a thermal fuse. This insulating substrate 6
5 is laminated with a film 71 having an insulating property. When the metal conductor path is not formed on the lower surface of the insulating substrate 72, the film 71 may be omitted.

On the upper surface of the insulating substrate 72 having flexibility,
A plurality of power metal conductor paths 73 to 75 and control metal conductor paths 76 to 78 are formed. Power metal conductor track 7
For 3 to 75, a nickel thin plate is used. Copper foil is used for the control metal conductor paths 76 to 78. Reference numeral 79 denotes an overdischarge prevention circuit, reference numeral 80 denotes an overcharge prevention circuit, and reference numeral 81 denotes a voltage detection circuit.

The insulating substrate 72 is adhered to the insulating substrate 65 with an adhesive via the film 71 to form a two-layer flexible substrate as shown in FIG. In FIG. 7, the adhesive is omitted.

When connecting the metal conductor path of the insulating substrate 72 and the metal conductor path of the insulating substrate 65, through holes 83 to 86 are provided and they are connected by soldering or plating as shown in FIG.

In the above embodiment, the lithium ion battery has been described. However, the present invention can be applied to a flexible substrate constituting a power supply circuit of another rechargeable battery. Further, the present invention can be applied to a flexible substrate other than a power supply circuit of a battery. Further, as the metal material, copper, nickel and phosphor bronze have been described, but other metal materials such as iron, aluminum,
Gold or the like can be used. In addition to the combination of foil and thin plate, a combination of thin plates and a combination of foils may be used.

[0052]

According to the present invention, a plurality of types of metal conductor paths are formed on an insulating substrate by selecting an optimum metal material in consideration of the usage form, connection, wiring pattern, etc. of each metal conductor path. Therefore, the reliability of the connection and wiring is improved, and a desired current can be passed without burning.

Since a copper foil is used for a control metal conductor path to which electronic components are connected and a nickel thin plate is used for a power metal conductor path for extracting current from a lithium ion battery, the control metal conductor path is fine. It can be patterned, and the power metal conductor track can be spot-welded directly to the lithium-ion battery, and a large current can safely flow.

[Brief description of the drawings]

FIG. 1 is a plan view showing a flexible substrate of the present invention.

FIG. 2 is a cross-sectional view of a flexible board showing a state where a power metal conductor path and a control metal conductor path are connected by soldering;

FIG. 3 is a cross-sectional view of the flexible board showing a state in which a power metal conductor path and a control metal conductor path are connected using jumper wires.

FIG. 4 is an exploded perspective view of the lithium ion battery pack.

FIG. 5 is a cross-sectional view of a flexible substrate having metal conductor paths formed on both sides.

FIG. 6 is an exploded perspective view of a flexible substrate having a laminated structure.

FIG. 7 is a sectional view of the flexible substrate shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flexible board 11 Insulating board 12-16 Power metal conductor path 20-24 Control metal conductor path 44 Jumper wire 56 Control metal conductor path 58 Power metal conductor path 65,72 Insulating substrate 71 Film 66-69, 73-75 Metal conductor track for power 76-78 Metal conductor track for control

Claims (9)

[Claims] 1. An insulating substrate, wherein at least a first and a second metal material are used, and a metal conductor path made of a first metal material and a metal conductor path made of a second metal material are formed on an insulating substrate. Flexible board with multiple types of metal conductor paths. 2. A semiconductor device comprising: a first insulating substrate having at least a metal conductive path formed of a first metal material; and a second insulating substrate having at least a metal conductive path formed of a second metal material. A flexible substrate having a plurality of types of metal conductor paths, wherein the flexible substrate has a laminated structure formed by laminating an insulating substrate. 3. The flexible substrate having a plurality of types of metal conductor paths according to claim 1, wherein the first metal material is a nickel thin plate and the second metal material is a copper foil. 4. An insulating substrate, wherein at least a first metal material and a second metal material are used, and a power metal conductive path made of a first metal material and a control metal conductive path made of a second metal material are formed on an insulating substrate. A flexible substrate having a plurality of types of metal conductor paths. 5. The first metal material is a metal sheet,
5. The method according to claim 4, wherein the second metal material is a copper foil.
A flexible substrate having a plurality of types of metal conductor paths as described in the above. 6. The flexible substrate having a plurality of types of metal conductor paths according to claim 5, wherein a power metal conductor path and a control metal conductor path are formed on one surface of the insulating substrate. 7. A plurality of kinds of metal conductor tracks according to claim 5, wherein a power metal conductor track is formed on one side of the insulating substrate and a control metal conductor track is formed on another side. Flexible substrate to have. 8. The flexible substrate having a plurality of types of metal conductor paths according to claim 4, wherein the first metal material is a nickel thin plate. 9. The power metal conductor path has one end connected to a lithium ion battery and the control metal conductor path has one end connected to a control circuit.
A flexible substrate having a plurality of types of metal conductor paths as described in the above.