Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
2001-07-02
2004-04-06
Zarneke, David A. (Department: 2827)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S260000
Reexamination Certificate
active
06717062
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circuit board applied for a battery pack detachable from a portable electronic apparatus such as a portable telephone and a note type personal computer for example, and a method for producing the circuit board.
The present invention also relates to a circuit board module used for a portable telephone, etc. for example and applied for a battery pack with a built-in cell for a battery, and to a method for producing the circuit board module.
2. Description of the Related Art
In conventional ways, a battery pack with a buil-in cell for battery such as a lithium ion battery, etc. has been provided for a portable telephone and a note type personal computer for example, and the battery pack is detachable from main body of the portable telephone and the like. By using the above battery pack, the above portable telephone and the like can be used for certain time without being supplied power voltage from a commercial power source.
FIG. 5
is a perspective view showing an example such the battery pack and
FIG. 6
is a perspective view showing an example of a circuit board installed in the battery pack. The battery pack P provides a case
1
made of resin and the case
1
installs a circuit board
2
connected to a battery cell not shown.
On the circuit board
2
, a wiring pattern not shown is formed, and plural external terminal portions
4
are formed on lands
6
formed as a part of the wiring pattern by joining roughly square shaped Ni pieces
21
cut from hoop material of pure Ni for example. The circuit board
2
is supported along inside of the case
1
so that the external terminal portions
4
expose out through openings
5
(see
FIG. 5
) formed on the surface of the case
1
. The battery pack
1
is possible to connect electrically to the main body of the portable telephone (not shown) by contacting connector pins (not shown) formed at the main body.
At the circuit board
2
, connecting terminals
3
made of metal piece for connecting to the battery cell are provided. The circuit board
2
supplies electric power to the above main body and charges the battery cell through the connecting terminals
3
and each external terminal portion
4
. The circuit board
2
includes a protecting circuit (not shown) for preventing over charge and over discharge in the battery cell.
The external terminals
4
are formed by joining the Ni pieces
21
on the lands
6
of the wiring pattern as described above, or by plating the above Ni pieces
21
with Au for example.
However, the above Ni pieces
21
have comparatively high in contact resistance so that contact failure occasionally happens at connection to the main body of the portable telephone. Pure Ni is frequently used for the Ni pieces
21
and there is a problem that cost of the pure Ni increases and soldering on the lands
6
of the wiring pattern is difficult. Then, it is considerable that the external terminals
4
are formed by plating on the lands
6
of the wiring pattern with hard Au. However, there is a problem that Au has bad yield because Au is easy to have a scratch on the surface thereof.
Further, a battery pack with a built-in cell for battery such as a lithium ion battery, etc. has been provided for a portable telephone and a note type personal computer for example, and the battery pack is detachable from main body of the portable telephone and the like.
In the above battery pack, a circuit board module is assembled, which is constructed with a battery case for storing the cell for battery and a circuit board including a circuit for supplying electric power to the main body of the portable telephone and preventing over-discharge and over-charge. The battery case and the circuit board are connected electrically and/or mechanically by a roughly long rectangular joint body which hoop material of Ni, for example, is cut to the designated size.
In recent year, Al is frequently used for material of the battery case responding to a request of lightening a portable telephone, and so on. However, since the join body is made of Ni, desirable contact between metals can not be obtained in connection between the battery case and the joint body so that the connection does not become stable connecting state.
Then, so called clad material bonded with metal body consisting of different metal materials each other for connection between the battery case
121
and the circuit board
122
as shown in FIG.
19
and FIG.
20
. That is, the above-mentioned clad material is stood between the battery case
121
and a joint body
123
so as to joint the both. Concretely, when material of the battery case
121
is Al for example, a clad material in which metal material of one metal layer
124
a
is Al and metal material of other metal layer
124
b
is Ni as a joining member
124
is provided, and one metal layer
124
a
side of the joining member
124
is contacted to side face
121
a
of the battery case
121
. Then, the battery case
121
and the joining member
124
are joined by spot welding for example so as to integrate.
By such the way, other metal layer
124
b
side made of Ni of the joining member
124
exposes outside, and to other metal layer
124
b
of the joining member
124
, one end portion
123
a
of the joint body
123
made of Ni being the same metal material as the metal layer is joined by welding. Other end portion of bent joint body
123
and a pad portion
125
of the circuit board
122
are connected by soldering. Thus, the battery case
121
and the joint body
123
have good connection between metals and stable connecting state.
However, in the circuit board module of the above construction, when the circuit board
122
is connected to the battery case
121
, the joining member
124
made of clad material and the joint body made of Ni must be used each other. Accordingly, since parts cost becomes high because of many parts and welding operation for joining the joining member
124
to the battery case
121
or joining the joint body
123
to the joining member
124
takes time, there has been a problem that operation cost increases.
SUMMARY OF THE INVENTION
The invention is considered on the above-mentioned circumstances, the problem is to provide a circuit board decreasing parts cost and removing problems such as contact failure, a battery pack using the circuit board, and a method for producing the circuit board.
To solve the above problems, the invention has the following technical means.
According to a battery pack concerned in a first aspect of the invention, the battery pack comprises a board and an external terminal portion formed on the board for connecting to an external apparatus wherein the external terminal portion is constructed by clad material that plural metal layers having different metal material each other are laminated. Concretely, the external terminal is constructed by a first metal layer made of Cu, a second metal layer formed on the first metal layer and made of stainless steel, and a third metal layer formed on the second metal layer and made of Ni alloy.
According to the above construction, decrease of parts cost at the circuit board can be designed because the clad material constructed as above-mentioned for the external terminal portion provided in the battery pack instead of Ni piece expensive generally used for the conventional construction.
Since Cu is used for the first metal layer of the external terminal portion and the first metal layer is joined to the land of the wiring pattern formed on the board and made of Cu foil for example, contact between these metals becomes good state and adhesiveness of the external terminal portion to the wiring pattern can be raised. Since stainless steel is used for the second metal layer, corrosion resistance of whole of the external terminal portion can be raised and rigidity can be made large. For example, by setting thickness of the second metal layer to suitable value, bend at soldering the above-mentioned clad material on the circuit board by reflow process can be de
Nakamura Satoshi
Nishimura Kohshi
Morgan & Lewis & Bockius, LLP
Norris Jeremy
Rohm & Co., Ltd.
Zarneke David A.
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