JP2002124235A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance antistatic electricity property of a battery pack. SOLUTION: A battery case 10 is structured to be a two-piece type comprising a body part 11 and a lid part 12, and the lid part 12 comprises a frame body 15 made of plastics and an armor sheet 16 made of aluminum. A battery body 20 is housed, together with a protection circuit 30, within the battery case 10. An external connection terminal 31 is formed on a circuit board of the protection circuit 30. An aluminum foil tape 40 is bonded to a surface of the battery body 20 so as to be electrically connected to the connection terminal 31. The other end part of the tape 40 confronts the armor sheet with a slight gap left between them. When a high voltage is imposed, discharge can be easily performed via the gap, and thus the armor sheet 16 and the connection terminal 31 are in an electrically connectable state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack in which a battery body is housed in a battery case together with a protection circuit.

[0002]

2. Description of the Related Art For example, in a battery pack of a portable telephone, a battery main body and a protection circuit are housed in a thin box-shaped two-part battery case, and leads led out from the battery main body are connected to a circuit of the protection circuit. In general, a connection is made to an external connection terminal on a substrate, and the external connection terminal faces the outside through an opening formed in the battery case.

[0003] In such a battery pack, for example, a configuration in which one side of a battery case is formed in a frame shape having a large opening at the center and a metal exterior sheet is attached so as to close the opening is also attempted. Have been. According to this configuration,
Since a part of the battery case made of plus chic can be replaced by a metal outer sheet having high strength, further thinning becomes possible.

[0004]

However, when a metal exterior sheet is provided in a part of the battery case as in the above configuration, there has been a problem that resistance to static electricity is reduced. For example, in an environment where the air is dry, if a person with a large amount of static electricity tries to touch the battery pack,
A minute discharge may occur between the tip of the finger and the exterior sheet. Then, there arises a problem that the discharge current flows to the protection circuit in the battery case and damages an integrated circuit and the like on the protection circuit. Generally, the resistance to such static electricity is measured, for example, by connecting a negative terminal of a battery to a ground line and bringing a probe to which a high voltage is applied between the battery and the ground line close to the battery pack. However, in the case where the above-mentioned metal exterior sheet is provided, for example, at about 8 kv, a discharge path to the integrated circuit portion occurs, and the protection circuit may be damaged.

It is an object of the present invention to provide a battery pack which has been completed in view of the above circumstances and which can improve the resistance to static electricity.

[0006]

As a means for achieving the above object, the invention of claim 1 is to accommodate a battery body together with a protection circuit in a plastic battery case and connect the battery body to an external circuit via an external connection terminal. The battery pack is configured so as to be connectable, and the battery case is provided with a metal exterior sheet, which is characterized in that the exterior sheet can be electrically connected to the ground line of the protection circuit. Also,
According to a second aspect of the present invention, the battery case is configured such that a metal exterior sheet is attached to a plastic frame having an opening so as to cover the opening, and a conductive tape is attached to the battery body. Thus, the present invention is characterized in that one end of the outer sheet is overlapped with the external connection terminal and the other end is brought close to the outer sheet closing the opening so that the outer sheet can be electrically connected to the external connection terminal.

[0007]

According to the first aspect of the present invention, since the metal exterior sheet located on the surface of the battery pack is electrically connected to the ground line, it is assumed that the exterior sheet and the external ( Even if a discharge occurs between a finger and a measurement probe, for example, the discharge current does not flow into the protection circuit. As a result, it is possible to prevent the protection circuit from being damaged. In addition, as a ground line for connecting a metal exterior sheet, generally,
It is preferable to use any part between the negative terminal of the external connection terminal of the battery pack and the negative terminal of the battery body. When the plus terminal of the external connection terminal is connected to the minus terminal via a zener diode for overvoltage protection, for example, the connection may be made to the line on the plus terminal side. At a voltage at which external discharge occurs, the Zener diode turns on and the positive terminal side has the same potential as the ground line of the protection circuit. In short, it is only necessary that the discharge charge be able to flow into the ground line so as not to flow into the input side of the protection circuit. In addition, the state in which the exterior sheet can be electrically connected to the ground line is not limited to the case in which the exterior sheet is always in contact with each other or actually in contact with each other via a conductor.
Even in the state of being close to a small space, it is sufficient that the discharge current flows from the exterior sheet to the ground line through the space.

According to the second aspect of the present invention, since the battery case is composed of a plastic frame and a metal exterior sheet for closing the opening thereof, the battery case is formed by utilizing the reinforcing effect of the exterior sheet. The thickness can be reduced. In addition, since the exterior sheet can be electrically connected to the external connection terminals by attaching the conductive tape to the battery body, the connection operation is extremely simplified, and the manufacturing cost can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a battery pack for a portable telephone will be described below with reference to the drawings. The overall structure of this battery pack is shown in FIG. 1, in which a battery body 20 is housed in a thin box-shaped battery case 10. The battery case 10 is divided into two parts in the thickness direction. It comprises a part 11 and a lid part 12. In the battery case 10, a protection circuit 30 connected to the battery main body 20 via the lead 21 is also accommodated, and an external connection terminal 31 provided in the protection circuit 30 is formed on the lid 12 of the battery case 10. The window 13 is exposed to the outside.

Note that, as shown in FIG.
The main body 11 has a plastic frame 14 having an opening 14A and a metal sheet 1 for closing the opening 14A.
4B and a fixing sheet 14C for fixing the metal sheet 14B to the frame 14. On the other hand, the lid 12
Also, a plastic frame 15 having an opening 15A
And an aluminum exterior sheet 16 with an adhesive that closes the opening 15B. Also, the battery body 20
Is a flat shape in which a power generating element constituting a lithium ion type secondary battery is sealed with a resin film laminated with an aluminum foil, as shown in FIG. Sealing portions 21 and 22 formed by attachment are provided. And one sealing part 2
1, a pair of battery leads 23 is led out.

Now, the connection configuration between the battery body 20 and the protection circuit 30 will be described together with the operation procedure. First, an insulating tape 24 is attached to the sealing portion 21 of the battery body 20, and the lead 25 is welded to one of the battery leads 23.
The lead 25 is connected to a PTC 26 which is a temperature-sensitive current limiting element, and this is connected to the PTC 26 as shown by an arrow in FIG.
At the lead 26A. Then, as shown in FIG. 5, the battery body 20 is turned over, one connection terminal 32 of the protection circuit 30 is connected to the lead terminal 26A of the PTC 26, and the other connection terminal 32 is connected to the other battery of the battery body 20 via the lead 27. Connect to terminal 23. In this state, as shown in FIG. 6, the surface of the protection circuit 30 opposite to the external connection terminal 31 is in contact with the battery main body 20. .

Then, the battery body 20 is turned over again, and FIG.
As shown in FIG. 3, a non-solvent type silicone resin 35 is applied on the insulating tape 24, and the protection circuit 30 is rotated about 180 degrees in the direction shown by the arrow in FIG. Let it. Then, as shown in FIG. 8, the PTC 26 is
0 on the sealing portion 21. Therefore, as shown in FIG. 8, for example, an aluminum foil tape 40 coated with an adhesive on the back surface is attached so as to extend between the lead 25 corresponding to the ground line of the protection circuit 30 and the surface of the battery body 20. The length dimension of the aluminum foil tape 40 is set such that one end overlaps the lead 25 and the other end is located on the surface of the battery body 20 and within the opening 15A of the frame 15 of the lid 12. (See FIG. 9).

The battery body 20 is connected to the battery case 1.
The PTC 26 is accommodated in the main body 11, and the silicon resin 35 is again flown on the leads 25 and 27 together with the PTC 26 so that the leads 25 and 27 are embedded with the resin. When the main body 11 of the battery case 10 is closed by the lid 12, the silicon resin 35 is solidified while the back surface of the lid 12 is in contact with the silicon resin 35. In this state, FIG.
10, one end of the aluminum foil tape 40 is in contact with the lead 25, and the other end is the outer sheet 1 of the lid 12.
6 is very close.

According to the present embodiment having the above-described configuration, since the exterior sheet 16 of the battery case 10 is in a state where it can be electrically connected to the leads 25 via the aluminum foil tape 40, a large amount of Even if a person who has been charged has touched his / her finger and a discharge occurs between them, a discharge is similarly generated between the exterior sheet 16 and the aluminum foil tape 40 and leads to the lead 25, and eventually, the charge of the discharge immediately It flows from the external connection terminal 31 to the outside through the lead 25. As a result, it is possible to prevent unnecessary current from flowing through the protection circuit 30 to cause damage.

By the way, the result of conducting an anti-static test on the battery pack of this embodiment by the same method as the conventional one is shown. In the conventional case, the protection circuit was damaged at 8 kV.
In the present embodiment, the protection circuit 30 was not damaged even at 30 kV. The electric circuit diagram in this anti-static test is
This is as shown in FIG. That is, the positive lead 23 of the cell housed in the battery body 20 is connected to the positive external connection terminal 31 via the protection circuit 30, and the negative lead 23 of the cell is connected to the protection circuit 30 via the PTC 26. In the protection circuit 30, the charge / discharge control circuit 30A and the FETs 30B and 30C controlled by the charge / discharge control circuit 30A are interposed between the external connection terminal 31 on the negative side and between the external connection terminals 31 on the positive side and the negative side. A zener diode 30D is provided. One terminal of the tester is connected to the external connection terminal 31 on the negative side, and a probe is connected to the other terminal of the tester so as to approach the surface of the battery pack. A voltage of several kV to several tens kV is applied between both terminals of the tester to cause the probe to discharge. In the figure, 30E and 30F are input terminals for testing, and 30F is connected to the ground line of the protection circuit 30. In the battery pack of the present embodiment, discharge occurred from the probe toward the exterior sheet 16 of the battery pack, but the exterior sheet 16 continued to the lead 25 via the aluminum foil tape 40, and this was connected to the external connection terminal 31 on the minus side.
Connected to Therefore, it is considered that the current at the time of discharging from the probe to the exterior sheet 16 does not flow into the charge / discharge control circuit 30A or the like of the protection circuit 30 and the damage can be prevented.

<Other Embodiments>

The present invention is not limited to the embodiment described above with reference to the drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further depart from the gist other than the following. Various changes can be made without departing from the scope of the present invention.

(1) In the above embodiment, the aluminum foil tape 40 is provided so as to extend between the exterior sheet 16 and the leads 25. However, the present invention is not limited to this, and the exterior sheet 16 and the three external connection terminals 31 are provided. May be provided so as to be provided between them. This is because, when a voltage causing an external discharge is applied, the Zener diode 30D turns on, and the positive terminal 31 and the data terminal 31 also have the same potential as the ground line of the protection circuit 30. Further, any portion may be used as long as it can be at the same potential as the ground line of the protection circuit 30, for example, between the PTC 26 and the FET 30B.
It may be between the FET 30C and the negative terminal 31 or the test terminal 30F.

(2) The connection between the exterior sheet 16 and the external connection terminals 31 is not limited to the aluminum foil tape 40, but may be a conductor, an FPC, or the like.

[Brief description of the drawings]

FIG. 1 is a sectional view of a battery pack showing one embodiment of the present invention.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is a perspective view showing an assembling process and showing a state before attaching an insulating tape;

FIG. 4 is a perspective view showing a state after the lead 25 is attached.

FIG. 5 is a perspective view showing a state before the protection circuit 30 is attached.

FIG. 6 is a perspective view showing a state after the protection circuit 30 is mounted.

FIG. 7 is a perspective view showing a state after application of a resin.

FIG. 8 is a perspective view showing a state in which the lead 25 is embedded in a resin.

FIG. 9 is a plan view showing a state where the battery main body is incorporated in a battery case.

FIG. 10 is an enlarged sectional view of the same.

FIG. 11 is a block diagram showing the inside of a battery pack.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Battery case 11 ... Body part 12 ... Lid part 20 ... Battery body 25,27 ... Lead 26 ... PTC (temperature-sensitive current limiting element) 30 ... Protective circuit 40 ... Aluminum foil tape

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuyuki Kaneda F-term (reference) 5H011 AA04 CC00 CC06 5H040 AA20 AA35 in GS Melcotech Co., Ltd. DD01 DD06

Claims (2)

[Claims] The battery body is housed in a plastic battery case together with a protection circuit so as to be connectable to an external circuit via an external connection terminal, and the battery case is provided with a metal exterior sheet. A battery pack, wherein the exterior sheet is electrically connectable to a ground line of the protection circuit. 2. The battery case according to claim 1, wherein a metal outer sheet is attached to a plastic frame having an opening so as to cover the opening, and a conductive tape is attached to the battery body. The exterior sheet can be electrically connected to the external connection terminal by overlapping one end thereof with the external connection terminal and bringing the other end close to the exterior sheet closing the opening. Item 7. The battery pack according to Item 1.