JP3272225B2 - Battery pack - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack having a battery built in a case. In particular, the present invention relates to a battery pack in which a printed circuit board such as a protection circuit is built in a case.

[0002]

2. Description of the Related Art A battery pack having a built-in protection circuit for a battery or an electronic circuit for indicating the remaining capacity of a battery has a printed circuit board in which electronic circuit components are mounted in a case. For example, in a battery pack containing a lithium ion secondary battery, it is necessary to incorporate a protection circuit in the case in order to prevent the battery from being overcharged or overdischarged. Lithium-ion secondary batteries have the advantage of a larger charge capacity compared to nickel-cadmium batteries, etc.
This is because the adverse effects of overcharging and overdischarging are large. Further, the battery pack for displaying the remaining capacity of the battery also needs to incorporate an electronic circuit for calculating and displaying the remaining capacity from the charge amount and the discharge amount of the battery.

In a battery pack containing an electronic circuit, electronic circuit components are mounted on a printed circuit board, and the printed circuit board is contained in a case. A battery pack with a built-in printed circuit board requires a storage space for the printed circuit board, and the outer shape of the case becomes large. It is extremely important for the battery pack to have as large a charging capacity as possible with respect to the size of the external shape. Even if the charge capacity of the battery is large, if the battery is stored in the case and the external shape of the case becomes large, the volumetric efficiency of the battery is substantially deteriorated.

Further, a battery pack in which a battery and a printed circuit board are built in a case is provided with a surface electrode exposed outside the case, and the printed circuit board is electrically connected to the surface electrode. As the surface electrode, a metal plate as thin as possible is used to make the battery pack light. However, when the surface electrode is made of a thin metal plate, it is difficult to obtain a sufficient strength, and there is a disadvantage that the surface electrode is easily deformed. This adverse effect can be effectively prevented by press forming into a shape having ribs on the outer periphery of the metal plate. This is because the outer ribs reinforce the thin metal plate.
However, the surface electrode provided with the ribs on the outer periphery of the metal plate has a drawback that it becomes substantially thicker and enlarges the outer shape of the battery pack.

[0005]

SUMMARY OF THE INVENTION The present invention has been developed for the purpose of overcoming the drawbacks of the conventional battery pack having a built-in printed circuit board. Built-in printed circuit board with built-in circuit components, or built-in connection parts for electrically connecting the surface electrode to the printed circuit board, and as a tough surface electrode made of a thin metal plate, and built-in printed circuit board and connection parts To provide a battery pack that can have a compact external shape with improved space efficiency.

[0006]

The battery pack of the present invention comprises:
The following structure is provided to achieve the above object. The battery pack according to claim 1 of the present invention includes
A battery 4 having substantially the same shape as one end face of the battery 4;
The printed circuit board 3 which is opposed to and proximate to one end face of the printed circuit board 4 is incorporated. Printed circuit board 3 has almost the same shape as printed circuit board 3
Surface electrode 5 is connected. Surface electrode 5 is case 1
And is electrically connected to an electric device to which the battery pack is mounted. Further, in the battery pack of the present invention, the surface electrode 5 is formed by press-molding a metal plate. The surface electrode 5 is press-formed into a shape having a rib 5A on the periphery of a metal plate, and a concave portion is provided on the surface opposite to the exposed surface exposed outside the case 1. The electronic circuit component 2 mounted on the printed circuit board 3 is accommodated in the concave portion of the surface electrode 5.

Further, in the battery pack according to the second aspect of the present invention, a connection part 6 for electrically connecting the surface electrode 5 to the printed circuit board 3 is accommodated in a recess of the surface electrode 5 formed by pressing a metal plate. are doing.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify a battery pack for embodying the technical idea of the present invention, and the present invention does not specify a battery pack as follows.

Further, in this specification, in order to facilitate understanding of the claims, the numbers corresponding to the members described in the embodiments will be referred to as "claims" and " In the column of “Means of the above”. However, the members described in the claims are not limited to the members of the embodiments.

An embodiment of the battery pack of the present invention is shown in FIG.
Are shown in an exploded perspective view and a sectional view of FIG. In the battery packs shown in these figures, the case 1 includes one battery 4 having the positive pole 4A as the positive pole and the negative pole on the entire outer can including the non-convex pole 4B. The polarity of the battery 4 is as follows: the salient pole 4A is −, and the non- salient pole 4B is +.
In general, + is a salient pole 4A, and-is a non-convex pole 4B. In addition, two or more batteries 4 incorporated in the case 1 can be stored in a straight line.

The battery 4 is a cylindrical lithium-ion secondary battery. However, the present invention does not specify the battery 4 as a lithium-ion secondary battery, but may be, for example, a nickel-cadmium battery or a nickel-hydrogen battery. A pack battery in which the built-in battery 4 is a lithium-ion secondary battery can increase the electromotive force. For example, one lithium-ion secondary battery corresponds to about three nickel-cadmium batteries. A voltage of 3.6V can be generated.

The case 1 containing one battery 4 is formed into a cylindrical shape and is a molded article of plastic having insulating properties. Case 1 is divided vertically into two parts as shown in the figure. At both ends of the case 1, electrode windows 7 are opened. The electrode window 7 provided at the right end of the case 1 protrudes the salient pole 4A of the battery 4 from here, and is electrically connected to the outside.

In FIG. 1, a surface electrode 5 is mounted on an electrode window 7 provided at the left end of the case 1. The surface electrode 5 is exposed to the outside of the case 1 through the electrode window 7 and is electrically connected to an electric device on which the battery pack is mounted.

The surface electrode 5 is a press-formed product of a metal plate. The surface electrode 5 is press-formed into a shape in which a rib 5A is provided on the outer peripheral edge of the disk. The surface electrode 5 is pressed in a disk shape substantially equal to the outer shape of the printed circuit board 3. The surface electrode 5 has a concave portion formed on the opposite surface of the exposed surface exposed to the outside of the case 1, that is, on the right surface of the surface electrode 5 in the drawing, by the outer rib 5 </ b> A. The rib 5A reinforces the surface electrode 5 and prevents the entire electrode 5 from being deformed. The thickness of the metal plate serving as the surface electrode 5 is set to an optimum value in consideration of the size of the surface electrode 5, but includes the AA type battery 4.
0.2 to 0.4 mm. The height of the rib 5A is such that the electronic circuit component 2 mounted on the printed circuit board 3 can be accommodated in the recess, for example, about 2 mm, preferably 1 to 5 mm.
Designed to.

A part of the rib 5A of the surface electrode 5 is projected to form a connection tab 5a of the printed circuit board 3. The connection tab 5a is inserted into a through hole 3A provided in the printed board 3, and is soldered to the printed board 3 to be electrically connected and fixed. The surface electrode 5 shown in the figure is provided with a connection tab 5a at a position facing the connection tab 5a. Three or more connection tabs 5a can be provided at substantially equal intervals. The connection tab 5a is fixed to the printed circuit board 3, and the surface electrode 5 is connected to the printed circuit board 3.
And fixed securely. The surface electrode 5 shown in FIG.
Is bent outward to provide a flange 5b along the rib 5A. The flange 5b is provided on the peripheral wall 1A provided on the case 1.
And the printed circuit board 3. The flange 5b contacts the surface of the printed circuit board 3 with a large area and prevents the printed circuit board 3 from directly contacting the peripheral wall 1A of the case 1 to reinforce the printed circuit board 3 and the peripheral wall 1A of the case 1. I do.

The surface electrode 5 is electrically connected to the printed circuit board 3, and the printed circuit board 3 is connected to the battery 4 via a lead tab 8.
Is connected to the non-convex pole 4B. Further, the printed circuit board 3
Is connected to the salient pole 4A of the battery 4 via the lead wire 9. Between the printed circuit board 3 and the battery 4, a separator 10 for insulating the printed circuit board 3 and the battery 4 is provided. As the separator 10, a plastic film or a plastic plate having excellent insulation properties is used.

The battery 4 is housed in the case 1 as a battery assembly in which the surface electrode 5 and the printed board 3 are connected. The battery assembly includes a battery 4, a printed circuit board 3, and a surface electrode 5. The printed circuit board 3 has mounted thereon the electronic circuit components 2 constituting a protection circuit for preventing the battery 4 from being overcharged and overdischarged. The printed circuit board 3 has a disk shape of substantially the same size on the bottom surface of the battery 4 and the electronic circuit components 2 are mounted on both sides. Power for an electronic circuit mounted on the printed circuit board 3 is supplied from a battery 4. Therefore, the printed circuit board 3 is electrically connected to the positive and negative electrodes of the battery 4.
In FIG. 1, a salient pole 4A of a battery 4 is connected to a printed circuit board 3 via a lead wire 9, and a non-salient pole 4B is a lead tab 8
Is connected to the printed circuit board 3 via the.

The lead wire 9 is optimally a flexible one in which a metal foil or a conductive layer is adhered to a flexible insulating sheet. The thin lead wire 9 is provided between the battery 4 and the case 1. The lead wire 9 has an elongated strip shape, and is connected to both ends of the connection plate 11 by soldering. One connection plate 11 is connected to the salient pole 4 </ b> A of the battery 4, and the other connection plate 11 is connected to the printed circuit board 3. Salient pole 4A
The connection plate 11 is slightly larger so as to be able to contact the salient pole 4A with a large area, for example, in a disk shape.
One end of the disk is bent and connected to the lead wire 9.

In the battery 4 shown in FIG. 1, the salient pole 4A is a positive pole, and the non-convex pole 4B and the outer can of the battery 4 are a negative pole. Therefore, in order to prevent the lead wire 9 connected to the positive electrode from coming into contact with the outer can of the battery 4 and short-circuiting, the lead wire 9 has a surface facing the battery 4 as an insulating sheet and a surface facing the case 1 has a metal surface. A foil and a conductive layer are provided.

A battery assembly in which the printed board 3 and the battery 4 are connected is housed in the case 1. The salient pole 4A of the battery 4 is connected to the connection plate 11, and the connection plate 1
1 is exposed from the electrode window 7 to the outside of the case 1 and serves as a positive electrode of the battery pack. The non-convex pole 4B of the battery 4 is a lead tab 8
And the surface electrode 5 via the printed circuit board 3, and the surface electrode 5 is exposed to the outside through the electrode window 7 of the case 1.

The surface electrode 5 and the printed circuit board 3 connected to each other are sandwiched between the peripheral wall 1A of the cylindrical case 1 and the projection 1B, and are arranged at fixed positions. In order to hold the surface electrode 5 and the printed circuit board 3 in place, the case 1 shown in the figure is formed integrally with a peripheral wall 1A protruding to the center along the left edge, and further separated from the peripheral wall 1A to form an inner surface of the case 1. And the projection 1B is integrally formed. The printed circuit board 3 and the surface electrode 5 are sandwiched between the peripheral wall 1A and the protrusion 1B and are held at fixed positions.

The vertically divided case 1 is closed by setting a battery assembly, and a heat-shrinkable sheet 12 is adhered to the surface and connected. The heat-shrinkable sheet 12 is adhered to the surface of the case 1 via an adhesive or a pressure-sensitive adhesive. After being adhered to the surface of the case 1, the heat-shrinkable sheet 12 is heated and shrunk to connect the case 1 without gaps. Heat shrinkable sheet 12
Is characterized in that the case 1 can be reliably connected from the outside.
Furthermore, the heat-shrinkable sheet 12 can eliminate the need for ultrasonic welding or bonding with an adhesive when bonding between the two divided cases 1. Therefore, since assembly of the case can be simplified, and ultrasonic mounting is not required, the present invention is most suitable for joining between cases of a battery pack containing a lithium ion battery in which circuit components are mounted.

The battery pack shown in the exploded perspective view of FIG. 3 and the sectional view of FIG.
A connection part 6 for electrically connecting the printed board 3 to the surface electrode 5 is provided. As shown in the drawing, the connection part 6 is a disk having a central portion protruding in the direction of the battery 4 and having a concave portion on the surface side, and is manufactured by pressing with a conductive metal plate. Connection parts 6 are printed circuit board 3
To make electrical connection. An insulating material 13 is provided between the connection part 6 and the surface electrode 5 in a recess provided at the center of the connection part 6. The insulating material 13 has a disk shape and is made of insulating plastic or paper.
As shown in the cross-sectional view of FIG.
Is insulated from the center hole 5B provided at the center.

The insulation of the center hole 5B of the surface electrode 5 is as follows.
This is to prevent the non-convex pole 4B of the battery pack from being connected to the electrical equipment when the battery pack is mounted on the electrical equipment with the + and-reversed. The battery pack shown in FIG.
The electrode at the upper end connected to the convex pole 4A is located at the center of the case 1, and the electrode at the lower end connected to the non-convex pole 4B of the battery 4 is exposed at a portion other than the center of the case 1. Accordingly, the contact point of the electric device is located at a position where one (+ pole in the illustrated battery pack) is connected to the center of the battery pack and the other (− pole in the illustrated battery pack) is connected to the periphery of the battery pack. When the battery pack is mounted in the +/- reverse direction, the battery pack does not come into contact with the contacts of the electric device.

The surface electrode 5 of the battery pack shown in FIGS. 3 and 4
Is press-formed into a cap shape attached to the end of the case 1.
This surface electrode is manufactured by press-forming a metal plate.
The surface electrode 5 is connected to the printed circuit board 3 via the intermediate plate 9.
And is exposed outside the case 1 to form one electrode of the battery pack. The cylindrical portion of the surface electrode 5 is attached to the case 1 which is divided into upper and lower parts.
One end. The surface electrode 5 has a dowel 5c on the bottom surface, which is spot-welded to be connected to the intermediate plate 9. Since the surface electrode 5 shown in the figure has a side wall instead of a flat plate shape, the battery pack having the surface electrode 5 attached to the case 1 has not only an end surface to which the surface electrode 5 is fixed but also a cross-sectional view of FIG. The electrodes are also exposed on the side surface of the battery pack, and can be electrically connected to the contacts of electric equipment. The case 1 whose one end is connected by the surface electrode 5 has a heat-shrinkable sheet 12 attached to the outer periphery in the same manner as the battery pack shown in FIGS.
Be linked.

[0026]

According to the battery pack of the present invention, the space efficiency for incorporating a printed circuit board or the like is improved, the size of the battery pack is reduced, and the surface electrode is formed of a thin metal. Realizes the features that can be made tough with plates. This is because the battery pack of the present invention is configured such that the surface electrode is press-molded to provide a concave portion, and the concave portion accommodates an electronic circuit component mounted on a printed circuit board. By pressing a metal plate to form a surface electrode having ribs on the outer periphery, even a thin metal plate can be reinforced to increase the strength. In addition, there is also an effect that weight reduction can be achieved by making the metal plate thin. Further, by arranging the electronic circuit components mounted on the printed circuit board in the space in which the ribs are provided to form the concave portions, the space can be used efficiently. In particular, in a battery pack such as a lithium ion battery having an overcharge / discharge prevention circuit and a remaining amount display circuit,
In order to configure these electronic circuits, it is necessary to use those in which various electronic circuit components are mounted on a printed circuit board. Since such a printed circuit board has a large thickness, it is necessary to provide a storage space in order to be built in the battery pack, and it is necessary to increase the outer shape of the case. In the battery pack of the present invention, a concave portion is formed by providing a rib on the surface electrode. The printed circuit board on which the electronic circuit component is mounted and the surface electrode are connected so that the electronic circuit component is located in the recess. For this reason, it is possible to effectively utilize the space formed by reinforcing the surface electrodes, improve the occupied volume of the electronic circuit components, and realize the feature that the external shape of the battery pack can be reduced in size.

Further, in the battery pack according to the second aspect of the present invention, the connection parts for electrically connecting the surface electrode and the printed circuit board are housed in the recess formed as the surface electrode by the same configuration as described above. Therefore, the volumetric efficiency of the battery pack can be improved and the battery pack can be designed to be compact. Furthermore, since a thin metal plate can be used for the surface electrode, it is possible to reduce the cost and weight, and even if the thin metal plate is provided with ribs and reinforced, it can be used firmly and safely.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a battery pack according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the battery pack according to the embodiment of the present invention;

FIG. 3 is an exploded perspective view showing a battery pack according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a battery pack according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case 1A ... Perimeter wall 1B ... Protrusion 2 ... Electronic circuit component 3 ... Printed circuit board 3A ... Through-hole 4 ... Battery 4A ... Convex pole 4B ... Non-convex pole 5 ... Surface electrode 5A ... Rib 5a ... Connection tab 5b ... Flange 5B ... Center hole 5C ... Dowel 6 ... Connection part 7 ... Electrode window 8 ... Lead tab 9 ... Lead wire 10 ... Separator 11 ... Connection plate 12 ... Heat shrink sheet 13 ... Insulation material

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-63552 (JP, A) JP-A-9-129192 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/10

Claims (2)

(57) [Claims] 1. A case (1), a battery (4), and a battery
It has substantially the same shape as one end face of (4), and is one of the batteries (4).
A printed circuit board (3) which is opposed to and close to the end surface is built in, and the printed circuit board (3) includes a printed circuit board (3).
A surface electrode (5) having substantially the same shape as that of the battery pack is connected, and the surface electrode (5) is exposed outside the case (1) and electrically connected to an electric device to which the battery pack is mounted. is <br/>, given a surface electrode (5) is formed by pressing a metal plate, a surface electrode (5) is press-molded into a shape that the ribs (5A) is provided on the periphery of the metal plate, the case (1 A pack characterized in that a concave portion is provided on the surface opposite to the exposed surface exposed outside, and the electronic circuit component (2) mounted on the printed circuit board (3) is stored in the concave portion. battery. 2. A case (1), a battery (4), and a battery
It has substantially the same shape as one end face of (4), and is one of the batteries (4).
A printed circuit board (3) which is opposed to and close to the end surface is built in, and the printed circuit board (3) includes a printed circuit board (3).
A surface electrode (5) having substantially the same shape as that of the battery pack is connected, and the surface electrode (5) is exposed outside the case (1) and electrically connected to an electric device to which the battery pack is mounted. is <br/>, given a surface electrode (5) is formed by pressing a metal plate, a surface electrode (5) is press-molded into a shape that the ribs (5A) is provided on the periphery of the metal plate, the case (1 A concave portion is provided on the surface opposite to the exposed surface which is exposed to the outside, and a connection part (6) for electrically connecting the surface electrode (5) to the printed circuit board (3) is accommodated in the concave portion. Features a battery pack.