JP3477656B2 - Battery external terminal and battery pack using it - 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 including a battery external terminal and a battery such as a lithium-ion battery using the external terminal.

[0002]

2. Description of the Related Art Batteries such as lithium-ion batteries, which are built into small electronic devices such as portable radio telephones, portable personal computers, and portable video cameras, have conventionally been used as bag-like battery containers made of a flexible material. An electric storage element housed therein, and a lead connected to the electric storage element and exposed to the outside of the battery container are provided.

Since this lead cannot be directly connected to the terminal on the electronic equipment main body side, the lead is connected to an external terminal made of a metal plate backed by a plastic terminal support plate, and if necessary, a PTC element, Fuse, FE
A protective element such as a T element is connected, the external terminal and the protective element are housed in a box together with a battery, and attached to an electronic device as a battery pack. At the same time as mounting to electronic equipment,
Electric power is supplied by contacting the external terminal with the terminal on the electronic device body side.

Conventionally, as an external terminal of a battery, it is backed with a plastic terminal supporting plate as described above so as not to be deformed during use or short-circuited between electrodes having different polarities. A fixed metal plate was used. This metal plate has, for example, phosphor bronze as a base material, its surface is nickel-plated and gold-plated, is cut into a predetermined terminal shape, and is bent at a right angle so as to wrap around from the side surface to the back surface of the terminal support plate. It was a snap on the backing plate.

[0005]

However, if a metal plate to be an external terminal is plated in advance and then cut and bent into a predetermined terminal shape, the cut surface is not plated, and the portion rusts. Therefore, the resistance is increased and the current collecting property is deteriorated, and the cost is increased by coating with insulating rubber or the like to prevent rust. On the other hand, even if the base material is cut and plated after bending, the corners are cracked and rusted from that portion, and it is rather costly to individually plate the plated contacts after bending. Therefore, an object of the present invention is to provide an external terminal of a battery excellent in current collecting property at low cost.

[0006]

In order to solve the problem, an external terminal of the present invention comprises a copper layer printed in a predetermined pattern on an insulating substrate, and a nickel layer covering the copper layer. And a gold layer that covers the nickel layer, and is provided so as to be connected to a battery and to be able to contact a terminal of an external device.

According to the external terminal of the present invention, since the copper layer as the base material is printed in advance in a predetermined pattern on the insulating substrate, neither cutting nor bending is required. This copper layer can be formed by a usual printed wiring technique. Since the copper layer is covered with the nickel layer and the gold layer, the copper layer is not exposed, and since the outermost layer is made of gold, the copper layer is prevented from being oxidized and contacts with the terminals on the electronic device body side. The resistance is low. Further, since the nickel layer exists between the copper layer and the gold layer, the corrosion gas resistance is improved and the adhesion strength of the gold layer is increased. Therefore, it is excellent in current collecting property as an external terminal.
Incidentally, it is desirable that the nickel layer covers the entire surface of the copper layer including the end face, and the gold layer covers the entire surface of the nickel layer.
It may be within a range that can be covered by a general technique such as plating. This is because the copper layer is substantially protected because other liquids are less likely to enter the portion where the plating liquid does not enter.

In the present invention, it is preferable that the nickel layer is formed by plating such as matte nickel plating and has a thickness of 2 μm or more and 10 μm or less. This is because it can be formed at low cost by plating, and if the thickness is less than 2 μm, the effect of preventing the oxidation of the copper layer becomes poor, and if it exceeds 5 μm, the corners are likely to crack.

The gold layer is preferably formed by plating or vapor deposition and has a thickness of 0.5 μm or more. If the thickness is less than 0.5 μm, the gold layer is peeled off and the nickel layer is exposed and corroded during repeated contact with the terminal on the electronic device body side, and the current collecting property is reduced. The cost is low in a battery pack including the above external terminals, a lithium ion battery connected to the external terminals, and a box accommodating the external terminals and the lithium ion battery.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The external terminals and the battery pack of the embodiment will be described with reference to the drawings. FIG. 1 is a plan view showing an external terminal and a battery pack of the present embodiment, FIG. 2 is an enlarged sectional view taken along the line AA, and FIG. 3 is an enlarged sectional view taken along the line BB. The battery pack 1 of the present embodiment includes a lithium battery including an electricity storage element, a bag 2 and a lead 3, a positive electrode terminal 41 as a first external terminal, a negative electrode terminal 42 as a second external terminal, a pattern fuse and a thermistor. Board 4 mounted on the surface,
The PTC element 5 and a box 6 including a fixed case 62 and a cover 61 are provided.

The storage element of the battery has a flat shape and is housed in a bag 2 made of a laminated film. The bag 2 is formed by wrapping the power storage element with a film and then bonding the inner surfaces of the film ends together to form a battery container. Therefore, the bag 2 also has a flat shape.
Further, the bag 2 has a bonding margin 21 extending in the surface direction, and two flat plate-type leads 3 are exposed from the space between the inner surfaces of the film of the bonding margin 21. The two leads 2 are connected to the positive electrode and the negative electrode of the electricity storage element, respectively, and are also connected to the PTC element 5.

The PTC element 5 is provided between the adhesive margin 21 and the case 62 of the box 6 and is connected in series with the substrate 4. The substrate 4 is located between the bonding margin 21 and the cover 61 of the box 6, and is provided with the L-shaped first rib 61 provided on the cover 61.
It is sandwiched between the cover 61 and the cover 61, and at the same time, the case 62
It is pressed down by the second rib 62a provided on the.
Therefore, the substrate 4 is fixed so that the surface of the substrate 4 contacts the inner surface of the cover 61. Further, as shown in FIG. 1, the cover 61 is provided with holes 61b at positions where the external terminals 41 and 42 are provided. Therefore, the external terminals 41 and 42 can come into contact with terminals (not shown) on the main body of the electronic device through the holes 61b.

The battery pack 1 of the present embodiment is provided with a substrate 4 and a PTC element 5 in a box 6 in addition to the battery. However, the substrate 4 is not covered by the PT between the bonding margin 21 and the cover 61.
The C element 5 is provided between the bonding margin 21 and the case 62, and there is no special space for the substrate 4 and the PTC element 5. That is, in the battery pack 1 of this embodiment, the space inside the box 6 is effectively used, and the size of the box 6 is almost the same as the size of the battery. Moreover, in the battery pack 1 of the present embodiment, the external terminals are both on the same surface as the positive electrode terminal 41 and the negative electrode terminal 42, so wiring of the electronic device is easy. Therefore, according to the battery pack 1 of the present embodiment, it is possible to design electronic devices smaller than conventional ones. further,
In the present embodiment, since the substrate 4 is held between the inner surface of the cover 61 and the first rib 61a and is pressed by the second rib 62a, the substrate 4 does not come off.

For the external terminals 41 and 42, a copper layer 7 is formed in a predetermined pattern by a printed wiring technique on a substrate 4 made of an insulating material such as plastic, and a nickel layer 8 is formed on the copper layer 7 by matte nickel plating. Gold layer 9 by gold plating on top
Is formed and configured. A nickel layer 8 is formed on the copper layer 7 already formed in a predetermined pattern by a plating technique.
Since the gold layer 9 and the gold layer 9 are provided, the bending process is not necessary, and the entire copper layer 7 including the end face is covered with the nickel layer 8 and the gold layer 9. Therefore, there is no fear of rusting during use. Therefore, it is not necessary to cover with insulating rubber. The nickel layer 8 and the gold layer 9 are not limited to pure nickel and pure gold, respectively, and may be alloys thereof.

[0015]

EXAMPLE A thin bendable plastic substrate having a copper layer with an area of 2.5 × 4 mm was prepared on the surface, and then matte nickel plating and hard gold plating were sequentially applied to form external terminals. The test was conducted. The number of observations and tests is 5 each. The results are shown in Table 1. ○ in the table
Indicates that all five were good, and x indicates that even one was defective.

[Observation] The surface after gold plating was observed with a magnifying glass to inspect for cracks. [Oxidation resistance test] The external terminals were exposed to an atmosphere of 60% RH and 90 ° C for 500 hours to inspect whether surface oxidation occurred. [Peeling resistance test] The operation of bringing the surfaces of the two external terminals into contact with each other and separating them from each other was repeated 100 times to examine whether or not the gold layer was peeled off.

[0017]

[Table 1]

[0018]

As described above, according to the present invention, the external terminals of the battery having excellent current collecting ability can be manufactured at low cost, so that the cost of the entire battery can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing a battery pack of an embodiment.

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged sectional view taken along line BB of FIG.

[Explanation of symbols]

1 battery pack 2 bags 21 Glue 3 leads 4 substrates 41 positive terminal, 42 negative terminal 5 PTC element 6 boxes 61 cover, 62 case 7 Copper layer 8 Nickel layer 9 gold layers

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Atsushi Kojima, Atsushi Kojima, Kichijoin, Minami-ku, Kyoto-shi, Kyoto Prefecture 5 Nitta Ichinodancho, GS Melcotec Co., Ltd. (72) Inventor, Masaki Kitamura, Kichishoin, Minami-ku, Kyoto Nishinosho Inobabacho No. 1 Japan Battery Co., Ltd. (72) Inventor Tetsuya Murai Kinoshoin, Minami-ku, Kyoto City, Kyoto Prefecture Nishinosho Inobabacho No. 1 Japan Battery Co., Ltd. (58) Fields investigated (Int .Cl. ⁷ , DB name) H01M 2 / 10,2 / 30

Claims (3)

(57) [Claims] 1. A method comprising: a copper layer printed in a predetermined pattern on an insulating substrate; a nickel layer covering the copper layer; and a gold layer covering the nickel layer, which is connected to a battery and externally. Characterized in that it is provided so as to be able to contact the terminal of the device,
Battery external terminals. 2. The nickel layer is formed by plating and has a thickness of 2 μm or more and 10 μm or less.
External terminal of the battery described in. 3. A process according to claim 1 and an external terminal according to any one of 2, the same lithium ion batteries connected, the battery pack characterized by comprising a box which houses them external terminals and lithium ion batteries.