JPH11297286A - Assembling method of battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and firmly adhere upper and lower cases together without deteriorating the performance of an electronic part housed therein. SOLUTION: An upper and lower case for battery pack 16, 17 are combined so as to mutually butt connecting surfaces 23a, 21 formed substantially on the whole circumference thereof. A projection 25 and receiving part 22 for welding are provided on the angle parts of the connecting surfaces 23a, 21. The upper case 16 is put on the lower case 17 containing a secondary battery, the part of the projection 25 is ultrasonically welded to temporarily fix the upper and lower cases 16, 17, and allowed to stand until the adhesive preliminarily applied to the connecting surfaces 23a, 31 entirely is hardened. Since substantially the whole circumference of the upper and lower cases 16, 17 is adhered by the adhesive, the adhesive strength is increased. Further, since they are temporarily fixed in the state where the connecting surfaces 23a, 21 are closely fitted to each other by ultrasonic welding, the upper and lower cases 16, 17 can be allowed to stand as they are without using a special fixing tool.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for assembling a battery pack in which a rechargeable battery is housed in a two-part resin pack body.

[0002]

2. Description of the Related Art In recent years, portable electronic devices, such as mobile phones, notebook computers, camcorders, and CD players, have been widely used. Many of these electronic devices use a chargeable / dischargeable battery pack as a power source. The battery pack is one in which a single secondary battery or a plurality of secondary batteries in series or in parallel are housed in a resin pack body, and is detachable from an electronic device or a charger. .

[0003] The secondary battery is mounted on a circuit board on which a charge / discharge protection circuit is formed, and is housed in the pack body integrally with the circuit board. The pack body is composed of an upper and lower case, which is a roughly square box divided into upper and lower parts.The two parts are firmly adhered so that they do not easily separate when subjected to an impact due to, for example, falling. Is done.

[0004]

As typical bonding methods for the upper and lower cases, there are a method using an adhesive such as an organic solvent and an ultrasonic welding method. In the method using an adhesive, a high adhesive strength can be obtained by applying the adhesive to the entire joint surface between the upper case and the lower case. However, the relative positional relationship between the upper and lower cases and the pressing force must be kept constant until the adhesive is completely cured. For this reason, a clamper for fixing the upper and lower cases in a state where they are pressed against each other is required, and the efficiency of the bonding operation is low.

In the ultrasonic welding method, a part of the bonding surface is melted and bonded by applying ultrasonic vibration, and the bonding can be instantaneously performed without the need for a clamper as in the above method. . On the other hand, if the welding area is increased to obtain a strong adhesive force,
Since the amount of energy of the ultrasonic wave applied to the lower case also increases, there is a concern that the performance of the electronic components on the circuit board may be reduced by the ultrasonic vibration generated at the time of welding.

The present invention has been made in view of the above circumstances, and provides a method of assembling a battery pack that can easily and firmly bond the upper and lower cases without deteriorating the performance of the stored electronic components. The purpose is to provide.

[0007]

In order to achieve the above-mentioned object, a method for assembling a battery pack according to the present invention comprises placing an upper case on a lower case accommodating a secondary battery, and then mounting the upper case or the lower case on the lower case. The upper case and the lower case are partially ultrasonically welded to each other through the welding projections, and the upper case and the lower case are temporarily fixed to each other by the ultrasonic welding. Is to cure the adhesive applied in advance to the adhesive. In addition, the upper case and the lower case
In the case of a polygon having at least four corners, it is preferable to form welding projections on at least two corners. Further, it is preferable that the projection for welding is a cone.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 4, a battery pack 10 has a battery unit 1 attached to a resin pack body 11.
2 are housed. The battery unit 12 includes a cylindrical secondary battery 13 and a circuit board 14 on which a protection circuit is formed.
It is composed of On one surface of the circuit board 14,
A secondary battery 13 is attached. Also, the circuit board 1
An electronic component constituting a protection circuit is attached to 4, and a connector 15 in which a pair of a power supply terminal, a connection detection terminal, a communication terminal, and the like are integrated is attached. The input / output terminals of an electronic device or a charger are connected to the connector 15.

The pack body 11 is constructed by combining an upper case 16 and a lower case 17 each of which is formed by dividing a rectangular box into upper and lower parts. A notch 18a for exposing the connector 15 is provided at the joint between these cases. , 18b are formed. In practice, a notch is formed in the pack body 11 in order to eliminate a mistake in loading the battery unit 12, and the right half and the left half of the planar shape are asymmetric. Also,
The upper case 16 and the lower case 17 are relative to each other, and in this example, a so-called lid having a plate shape is used as the upper case 16.

As shown in FIG. 3, a joining surface 21 having a height lower than that of the end face 17a is formed on the inner periphery of the opening edge of the lower case 17 over substantially the entire periphery. Also,
At four corners of the lower case 17, there are formed receiving portions 22 in which the joining surface 21 is cut out to be concave. As shown in FIG. 2, a joint 23 is formed on the lower surface of the upper case 16 so as to be in close contact with the joint surface 21 of the lower case 17.
A guide rib 24 that fits into the lower case 17 is provided inside the joint 23. Four corners of the upper case 16 are provided with welding projections 25 projecting from the joints 23. In this example, as the projection 25 for welding,
A cone with a sharp point is used.

As shown in FIG. 1, when the upper case 16 and the lower case 17 are combined, the guide ribs 24 of the upper case 16 are placed in the lower case 17 such that the outer peripheral surface thereof is in contact with the inner peripheral surface of the lower case 17. To the upper case 1
The protrusion 25 of 6 comes into contact with the receiving portion 22 of the lower case 17.
In this state, the joint surface 23a of the upper case 16 floats on the joint surface 21 of the lower case 17 with a slight gap.

As shown in FIG. 3, on the bottom surface of the lower case 17, a concave portion 26 into which each of the secondary batteries 13 enters and a partition plate 27 between each of the rows of secondary batteries 13 arranged in two rows. Is formed. The battery unit 12 is stably stored in the lower case 17 by the recess 26 and the partition plate 27.

In the process of assembling the battery pack 10, first, a plurality of secondary batteries 13 are mounted on a circuit board 14, and a battery unit 12 is manufactured. The battery unit 12 is housed in the lower case 17 with the mounting surface of the secondary battery 13 facing downward.

Next, an adhesive 30 is applied on the joint surface 21 of the lower case 17, and thereafter, the upper case 16 is put on the lower case 17. At this time, the guide rib 24 of the upper case 16 fits inside the lower case 17, and the lateral movement of the upper case 16 with respect to the lower case 17 is restricted. The protrusion 25 of the upper case 16 is connected to the receiving portion 2 of the lower case 17.
2, the upper case 16 and the lower case 17 are in a state where the joint surface 23a and the joint surface 21 are slightly separated from each other.

Next, the projections 25 of the upper and lower cases 16 and 17 will be described.
And the receiving portion 22 are ultrasonically welded. This ultrasonic welding
As shown in FIG. 5, the ultrasonic horn 28
By pressing the protrusion 25 against the receiving portion 22 side. While the ultrasonic horn 28 is pressed, ultrasonic waves are oscillated from the ultrasonic horn 28, and the ultrasonic oscillation is stopped at the same time as the pressing of the ultrasonic horn 28 is stopped. The ultrasonic wave oscillated from the ultrasonic horn 28 melts the contact portion between the projection 25 and the receiving portion 22, and the tip of the projection 25 is integrated on the receiving portion 22 (see FIG. 5B). When the four projections 25 and the receiving portions 22 are ultrasonically welded, the upper case 16 is slightly lowered toward the lower case 17, so that the joining surfaces 23 a and 21 are in close contact with the adhesive 30 interposed therebetween.

Thereafter, the pack body 11 containing the battery unit 12 is left to stand until the adhesive applied between the joint surface 23a and the joint surface 21 is hardened. On this occasion,
The upper case 16 and the lower case 17 become four by ultrasonic welding.
Since they are temporarily fixed at points, the relative positional relationship between the upper and lower cases 16 and 17 and the contact pressure are kept constant without using a clamper device.

When the adhesive is hardened, the upper case 16 and the lower case 17 are bonded almost all around by the adhesive, so that the bonding strength is strong. Therefore, even when an impact is applied due to, for example, dropping, the upper and lower cases 16 and 17 do not separate.

FIG. 6 shows an embodiment in which the upper case and the lower case are fitted by ribs and grooves. The lower case 35 has a groove 36 formed substantially all around the upper edge of the quadrilateral. On the other hand, the rib 3 that fits into the groove 36 over almost the entire periphery of the lower edge of the upper case 37.
8 are formed. The inner surfaces of these grooves 36 and the ribs 3
The outer surface of 8 constitutes a part of the joint surface. Also, at four corners of the upper case 37, so as to protrude from the ribs 38,
A quadrangular pyramid projection 39 is provided.

When bonding the upper case 37 to the lower case 35, an adhesive 40 is attached to at least one of the groove 36 and the rib 38.
Is applied. When the upper case 37 is correctly placed on the lower case 35 after the battery unit is loaded in the lower case 35, the ribs 38 fit into the grooves 36.

An ultrasonic horn is pressed against the portion where the projection 39 is provided, and ultrasonic vibration is applied to the projection 39.
Due to the ultrasonic vibration, the protrusion 39 and a part of the groove 36 to which the protrusion 39 contacts are melted. When the protrusion 39 is melted, the upper case 37 is slightly lowered toward the lower case 35, and the upper edge 37 of the lower case 35 is attached to the shoulder 4 of the upper case 37.
1 hits.

When the ultrasonic horn is removed from the upper case 37,
Since the melted portion 43 is instantaneously cured, the lower case 3
5 and the upper case 37 are spot-welded. Lower case 3
The adhesive applied to almost the entire circumference of the upper case 5 and the upper case 37 gradually cures, and after a few hours, the desired adhesive strength is generated.

In each of the above embodiments,
Ultrasonic welding was performed at four corners of the case, but at least two temporary fixing points may be used. Further, the position of the temporary fixing is preferably at the corner of the case where stress concentration is likely to occur, but may be in the middle of the side.

If the welding projection has a shape that becomes thinner as it approaches the tip, the transmission efficiency of ultrasonic energy increases, and for example, it may be a triangular pyramid. In addition, since the welding protrusion may be provided between the joining surfaces of the upper and lower cases, it is not always necessary to provide the protrusion on the upper case side, and may be provided on the lower case.

[0024]

As described above, according to the method for assembling a battery pack of the present invention, the upper and lower cases, which are divided into two parts, are almost completely bonded by the adhesive, so that the bonding strength is strong. Becomes Also, after applying the adhesive and combining the upper and lower cases, ultrasonic welding is performed in a spot, so the upper and lower cases are temporarily fixed with the joining surfaces in close contact, and special fixing equipment is used. Even if it is not, the relative positional relationship between the upper and lower cases and the contact pressure are kept constant. Therefore, it is possible to leave the adhesive applied to the adhesive surface until the adhesive is cured, and to prepare a fixing device as in the case of performing the adhesive only with the adhesive,
There is no need to perform fixing work.

Moreover, since the ultrasonic welding may be performed in a spot-like manner to the extent that the upper and lower cases can be temporarily fixed, the amount of energy of the ultrasonic waves oscillated at the time of welding can be reduced by the ultrasonic welding alone. The amount is extremely small as compared with the case of firmly bonding. Further, by making the shape of the projection for welding into a conical shape, the transmission efficiency of the ultrasonic energy is increased, and the welding is performed in a short time. As a result, the influence of the ultrasonic vibration generated at the time of welding on the electronic components on the circuit board is small, and the performance of the electronic components is not reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a pack body embodying the present invention.

FIG. 2 is a perspective view showing a configuration of an upper case.

FIG. 3 is a perspective view showing a configuration of a lower case.

FIG. 4 is a schematic diagram showing a configuration of a battery pack.

5A and 5B are explanatory views showing a welding method by an ultrasonic welding method, wherein FIG. 5A shows a state at the time of starting welding, and FIG. 5B shows a state after welding.

FIGS. 6A and 6B are cross-sectional views of main parts showing another configuration of a joint portion between an upper case and a lower case, wherein FIG. 6A shows a configuration on the upper case side, and FIG.

FIG. 7 is a cross-sectional view of a main part showing a joint state of the upper and lower cases shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Battery pack 11 Pack main body 12 Battery unit 14 Circuit board 13 Secondary battery 16, 37 Upper case 17, 35 Lower case 21, 23a Joining surface 22 Receiving part 23 Joining part 24 Guide rib 25, 39 Projection 30, 40 Adhesive 36 Groove 38 ribs

Claims (3)

[Claims] 1. A method for assembling a battery pack in which a secondary battery is housed in a resin pack body divided into two parts, an upper case and a lower case, wherein the upper case is housed in the lower case in which the secondary battery is housed. , The upper case and the lower case were partially ultrasonically welded through the welding projections provided on the upper case or the lower case, and the upper case and the lower case were temporarily fixed by this ultrasonic welding. A method for assembling a battery pack, comprising curing an adhesive previously applied to a joint surface between an upper case and a lower case in a state. 2. The apparatus according to claim 1, wherein the upper case and the lower case have a polygonal shape having at least four corners, and welding projections are formed at at least two corners. A method for assembling the battery pack described above. 3. The method according to claim 2, wherein the welding protrusion is a cone.