JPH0970892A - Case welding method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain large welding strength by stabilizing a welded state. SOLUTION: The inwardly bent recessed parts 3a, 3b of a battery case 1 are provided to the outer peripheral surfaces of the opening ends of upper and lower cases 1a, 1b and, when both cases 1a, 1b are abutted to each other, a groove part 3 is formed. The outer flange like welding pieces 4a, 4b protruding from the central part of the groove part 3 are provided to the opening end edges of both cases 1a, 1b. When a heating element 6 is brought into contact with both welding pieces 4a, 4b from the outside, both molten welding pieces 4a, 4b are solidified in the state stored in the groove part 3 and not diffused to the outside of the groove part 3. Therefore, large welding strength is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for welding a case in which a heating element is brought into contact to weld a butt portion, and more particularly, to a method and apparatus for welding a case capable of stabilizing the welding state. .

[0002]

2. Description of the Related Art Generally, when a pair of unit cases are made to abut against each other and the abutting portions are welded to each other to form an integrated case, they are welded by a welding method using ultrasonic waves. Is customary.

[0003]

However, when welding a small battery case or the like, there is a possibility that the protection circuit IC substrate or the like housed in the case may be damaged by ultrasonic vibration, so that ultrasonic waves are not applied. There is a problem that it cannot be welded by using.

Therefore, a heating and welding method using a heating body can be considered as a welding method that does not damage the contents in the case, but when welding the abutting portions of a pair of unit cases, the abutting is performed. Since the heating element has to be brought into contact with the portion from the outer peripheral side to be welded, there is a problem that it is not easy to stabilize the welding state.

Further, even if the plastic material of each unit case is different, welding failure may occur, and even when welding a long butt portion, the welding state is caused by uneven temperature distribution of the heating element. May not be stable.

The present invention has been made in view of the above situation, and stabilizes the welding state even in the case where a heating element is brought into contact with the abutting portions of a pair of unit cases from the outer peripheral side to perform large welding. It is an object of the present invention to obtain strength and improve the appearance of the welded portion.

Another object of the present invention is to provide a unit case made of different plastic materials,
It is to be able to stabilize the welded state.

Another object of the present invention is to make it possible to stabilize the welding state and obtain a high welding strength even if the outer peripheral shape of the abutting portion is complicated.

Another object of the present invention is to make the temperature distribution of the heating element uniform even when a long heating element is used.

Still another object of the present invention is to make it possible to make the temperature distribution of the heating element uniform and to maintain it at a set temperature.

[0011]

In order to achieve the above object, the present invention is directed to abutting portions of a pair of unit cases, the opening edges of which are abutted against each other, and a heating element is brought into contact with the abutting portions from the outer peripheral side. In the method for welding a case of welding, in the outer peripheral surface of the opening end of each unit case, a concave portion that bends toward the center is provided, and at the opening edge of each unit case,
It is characterized in that welding pieces protruding to the outer peripheral side are respectively provided, and both the welding pieces are melted to weld the abutting portion.

By the way, when the opening edges of both unit cases are abutted against each other, the recesses of both unit cases form a groove portion that opens to the outer peripheral side in the abutting portion, and both welded pieces are formed from the center of the groove portion. It will be in a protruding state. Then, when both welding pieces are melted by contact with the heating body, the melted welding pieces are stored in the groove portion and solidified. Therefore, it is possible to stabilize the welded state and obtain a large weld strength, and since the melted welded pieces do not diffuse to the outside of the groove portion, it is possible to improve the appearance of the welded portion.

The present invention is also characterized in that the protruding lengths of the respective welding pieces are made different from each other. As a result, the welding piece with the longer protruding length first comes into contact with the heating body and melts so as to wrap the welding piece with the shorter protruding length, and then both the welding pieces melt. For this reason,
It is possible to stabilize the welded state even when the two welded pieces are melted and solidified in a mixed state and different kinds of plastics are welded.

The present invention is also characterized in that each welding piece is provided with an uneven portion which engages with each other when the opening edges of both unit cases are butted. Then, due to the concavo-convex portions that engage with each other, when the two welding pieces are melted, they are mixed with each other, and the welding state can be further stabilized.

According to the present invention, a plurality of welding pieces are provided at intervals in the circumferential direction, and when the opening edges of both unit cases are butted against each other, the welding piece of one unit case is placed between the welding pieces of the other unit case. It is characterized in that the welding piece of the case is fitted and locked. By this fitting and locking, when the two welding pieces are melted, they are sufficiently meshed with each other, and the welding state can be further stabilized.

Further, according to the present invention, in the welding device for a case, the opening edges of a pair of unit cases are butted against each other, and a heating body is brought into contact with the butted parts from the outer peripheral side to weld the butted parts together. The body is composed of a plurality of plate-shaped bases formed in a trough shape whose front end surface is curved concavely in the plate thickness direction, and heating elements respectively arranged on the front end surfaces of these bases. It is characterized by being divided into a plurality of groups and contacting the abutting portion for each group. Thus, even if the outer peripheral shape of the abutting portion is complicated, it is possible to stabilize the welding state and obtain a large welding strength.

The present invention is also characterized in that a temperature compensating mechanism for equalizing the temperature in the longitudinal direction of the heating element is provided at the central portion in the plate width direction of each base.

By the way, since the amount of heat radiated at both end portions in the plate width direction of the base is larger than that at the central portion, the temperature of the central portion of the heating element becomes higher than that of the longitudinal end portions thereof. However, by providing a temperature compensating mechanism at the center of the substrate in the plate width direction, the temperature at the center becomes the same as the temperature at both ends in the longitudinal direction, and even when a long heating element is used, the temperature distribution of the heating element is Can be made uniform. As a specific example of the temperature compensation mechanism, it is conceivable to provide an opening in the substrate, dispose a substance having a different thermal conductivity, or dispose a heat dissipation member such as a fin.

According to the present invention, each heating element is further provided with a main power supply circuit which is energized in the longitudinal direction thereof and a plurality of temperature detection power supply circuits which are energized in the width direction at intervals in the longitudinal direction of the heating element. It is characterized in that each temperature detection power supply circuit also has a function of an auxiliary power supply circuit for temperature compensation.

When the temperature distribution in the longitudinal direction of the heating element is non-uniform, the resistance value of the heating element in the portion corresponding to each temperature detecting power supply circuit varies. By detecting this difference based on the change in the voltage value or the current value in each temperature detection power supply circuit, it becomes possible to detect the heating element temperature at the position corresponding to each temperature detection power supply circuit. Further, by partially raising the temperature of the heating element by the power of the temperature detection power supply circuit, it becomes possible to make the temperature distribution of the heating element uniform and to maintain the set temperature.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings. 1 and 2 show a welding device for a case according to a first embodiment of the present invention. In the drawings, reference numeral 1 is formed by abutting an upper case 1a and a lower case 1b in a bivalve shape. Upper and lower cases 1a, 1b
The butting portion is welded by bringing the heating body 2 of the impulse heating system into contact with it from the outer peripheral side.

As shown in FIG. 1, the upper and lower cases 1a and 1b are provided with concave portions 3a and 3b, respectively, which are bent toward the center side, that is, inside the battery case 1, as shown in FIG. Flange-shaped welding pieces 4a and 4b projecting to the outer peripheral side are respectively provided at the opening edges of the cases 1a and 1b, and the recesses 3a and 3b are provided at the abutting portions of the cases 1a and 1b. Due to this, the groove portion 3 opening to the outer peripheral side is formed. The two welding pieces 4a and 4b are adapted to project from the central portion of the groove portion 3 toward the outer peripheral side.

On the other hand, as shown in FIGS. 1 and 2, the heating body 2 is provided with four base bodies 5a, 5b, 5c and 5d corresponding to the respective sides of the rectangular battery case 1, and these bases 5a, 5b, 5c and 5d, respectively. The bases 5a, 5b, 5c, 5d are formed of a metal such as aluminum into a flat plate shape having a width corresponding to the length of each side of the battery case 1, and the tip surface thereof is, as shown in FIG. It is formed in a trough shape that is concavely curved in the plate thickness direction. A sheet-shaped heating element 6 is formed on the tip surface.
Are arranged in an insulating state following the shapes of the tip surfaces of the base bodies 5a, 5b, 5c and 5d. And, this heating element 6
Each substrate 5 is heated to a predetermined temperature by energization
By driving a, 5b, 5c, and 5d, both the welding pieces 4
By contacting with a and 4b, both welding pieces 4a and 4b
The butt portion can be welded by melting.

Each of the bases 5a, 5b, 5c, 5d
The heating element 6 may be brought into contact with both the welding pieces 4a and 4b at the same time, but the bases 5a, 5b, 5c and 5
d In order to prevent mutual interference, usually, a group of bases 5a, 5b and bases 5c, 5d facing each other with the battery case 1 in between.
Are divided into groups, and each group comes into contact with the abutting portion.

As shown in FIGS. 1 and 2, a temperature compensating mechanism for uniformizing the temperature of the heating element 6 in the longitudinal direction is provided in the central portion in the plate width direction near the tip of each of the base bodies 5a, 5b, 5c, 5d. The opening 7 is provided. Then, the amount of heat radiated from the central portion of the heating element 6 is reduced by the opening portion 7.
The amount of heat radiated from both ends in the longitudinal direction of the
The temperature distribution in the longitudinal direction can be made uniform. As the temperature compensation mechanism, in addition to the opening 7, a material having a different thermal conductivity from the bases 5a, 5b, 5c, 5d may be incorporated at the position of the opening 7, or a radiation fin may be attached. However, the same effect can be expected.

Next, the operation of this embodiment will be described. When welding the battery case 1, the upper and lower cases 1
After assembling predetermined equipment parts into a and 1b, both cases 1
1 and FIG.
State. As a result, the two welded pieces 4a and 4b are in a state of being superposed in a two-ply structure.

Next, the heating element 2 is attached to both welding pieces 4a, 4b,
The welding portions 4a and 4b are melted to weld the abutting portions of the cases 1a and 1b. FIG.
3 (a) to 3 (c) sequentially show the work at that time in accordance with the procedure. First, as shown in FIG. 3 (a), the two welding pieces 4a, 4b polymerized in a two-ply form are attached to the base from the outer peripheral side. 5
a, 5b, 5c, 5d are brought close to each other, and the heating element 6 at the tip thereof
Is brought into contact with both welding pieces 4a, 4b. Then, Fig. 3
As shown in (b), the two welding pieces 4a and 4b are melted, and the abutting portions of the two cases 1a and 1b are melted.
It is welded by a and 4b.

At this time, the two welding pieces 4a, 4b are formed in the both recesses 3
Since it is in a state of protruding from the central portion of the groove portion 3 constituted by a and 3b toward the outer peripheral side, both the melted welding pieces 4a and 4b are stored in the groove portion 3 and are shown in FIG. As shown in FIG. 4, the solidification is performed with the inside of the groove 3 being almost filled. For this reason, although the heating element 6 is brought into contact with both the welding pieces 4a and 4b from the outer peripheral side to weld the abutting portion, the welding state can be stabilized and a high welding strength can be obtained, and the melting Since both welding pieces 4a and 4b are solidified only in the groove 3 and do not diffuse to the outside, the appearance of the welding portion can be improved.

It should be noted that the four bases 5 constituting the heating element 2
The a, 5b, 5c, and 5d do not move toward both the welding pieces 4a and 4b at the same time as described above, but a group of the bases 5a and 5b and the bases 5c and 5 that face each other via the battery case 1.
It is divided into a group of d, and the abutting portion comes into contact with each group. Therefore, the bases 5a, 5b, 5
It is possible to prevent mutual interference between the c and 5d, and for example, the battery case 1 welded at one end of the base body 5a.
Since the corners of the battery will be welded again at one end of the base body 5c, it is possible to secure a sufficient welded state without specially providing a base body corresponding to each corner of the battery case 1. Become.

FIGS. 4 (a) and 4 (b) show a second embodiment of the present invention in which the protruding lengths of the welding pieces 4a, 4b are made different from each other.

That is, the welding piece 4b of the lower case 1b is
As shown in FIG. 4A, the protruding length is longer than that of the welding piece 4a of the upper case 1a, and the bases 5a, 5b, 5
When the heating elements 6 of c and 5d are brought into contact with each other, as shown in FIG. 4B, the tip of the welding piece 4b is first melted and the welding piece 4a is melted.
Wrap the tip of the, and then as shown in Figure 4 (c),
Both welding pieces 4a and 4b are melted and solidified in a mixed state. The other points are the same as those of the first embodiment, and the operation is the same.

However, since the protruding lengths of the welding pieces 4a and 4b are different from each other, when the heating element 6 is brought into contact with each other, first, the tip of the welding piece 4b is melted so that the tip of the welding piece 4a is melted. After encapsulation, the two welding pieces 4a and 4b are melted and solidified in a mixed state. Therefore, the welding state is stabilized not only when the upper and lower cases 1a and 1b are made of the same kind of plastic but also when the two cases 1a and 1b are made of different kinds of plastics. And high welding strength can be obtained.

FIG. 5 shows a third embodiment of the present invention. The abutting surfaces of the two welding pieces 4a, 4b are provided with, for example, square wave-shaped uneven portions 11 which engage with each other at the time of abutting. It was done like this. The other points are the same as those of the first embodiment, and the operation is the same.

Therefore, both the welding pieces 4 are formed by the uneven portion 11.
The contact area of a and 4b is expanded, and it is possible to promote mutual mixing when the two welding pieces 4a and 4b are melted. Therefore, the welded state can be made more stable.

FIGS. 6 and 7 show a fourth embodiment of the present invention, in which each welding piece 4a, 4b is attached to each case 1
A plurality of cases 1 and 1b are provided at intervals in the circumferential direction.
When the opening edges of a and 1b are butted, one welding piece 4
The other welding piece 4b, 4a is fitted and locked between a and 4b. The other points are the same as those of the first embodiment, and the operation is the same.

Since the welding pieces 4a, 4b are fitted and locked to each other, the two welding pieces 4a, 4b are sufficiently meshed with each other when the two welding pieces 4a, 4b are melted. It can be melted and solidified in a state to obtain a higher welding strength.

FIG. 8 shows a fifth embodiment of the present invention, in which the four bases 5a, 5b, and
Battery case 1 in which the tip shapes of 5c and 5d are plane circular
The curved surface has almost the same curvature as the above. The other points are the same as those of the first embodiment, and the operation is the same.

However, even in the case of the battery case 1 having a flat circular shape, a plurality of base bodies (four in the case of FIG. 8) having a circumferential length equal to or less than the length obtained by dividing the circumferential surface into four equal parts are used. By welding using the bases 5a, 5b, 5c, 5d), it is possible to obtain the same effect as in the case of the battery case 1 having a planar rectangular shape. Needless to say, in the case of the battery case 1 having a polygonal shape such as a hexagon or an octagon, the same number of bases as the number of sides are used for welding.

9 and 10 show a sixth embodiment of the present invention, in which each heating element 6 is provided with a temperature compensation mechanism.

That is, as shown in FIG. 9, the heating element 6 includes a main power source circuit 21 having a main power source 21a for energizing the heating element 6 in the longitudinal direction of the heating element 6, and temperature detecting power sources 22a, 23a.
For example, three temperature detecting power supply circuits 22, 23, 24 having 24a and energized in the width direction of the heating element 6 are respectively connected, and each of the temperature detecting power supply circuits 22, 23, 24 is connected.
24 are connected to the heating element 6 at equal intervals in the longitudinal direction. Then, each temperature detecting power supply circuit 22, 23, 24
The energization by means is performed in a state where the energization by the main power supply circuit 21 is cut off.

Each of the power sources 21a, 22a, 23a, 24
a is a current regulator 2 connected to the power supply 25 as shown in FIG.
It is composed of four transformers whose primary side is connected via 6, 27, 28 and 29, and each of the temperature detecting power supply circuits 22, 23 and 24 also serves as an auxiliary power supply circuit for temperature compensation. ing.

That is, since the resistance value of the heating element 6 changes depending on the temperature thereof, when the temperature of both ends of the heating element 6 in the longitudinal direction is lower than the central portion, the temperature detecting power supply circuits 22 and 24 and There will be a difference in voltage value and current value with the detection power supply circuit 23. Therefore, this difference is called a temperature difference, and the temperature distribution in the longitudinal direction of the heating element 6 is controlled by controlling the electric power of the temperature detection power supply circuits 22, 23, 24 so that the difference becomes zero. It can be made uniform.

Each temperature detecting power supply circuit 22, 23,
Normally, 24 are activated at the same time. However, when there is a possibility that sufficient accuracy cannot be obtained due to the adjacent temperature detection power supply circuits being too close to each other, each temperature detection power supply circuit 22, 23 and 24 may be sequentially activated.

Since the heating element 6 is provided with a plurality of temperature detecting power supply circuits 22, 23 and 24, it is possible to accurately detect the temperature variation in the longitudinal direction of the heating element 6. Moreover, this can be corrected to make the temperature distribution uniform.

The present invention is not limited to the embodiments described above, and the structures of the embodiments may be used in combination with each other.

In each of the above embodiments, the case of welding the battery case 1 has been described as an example, but the present invention can be applied to other cases as well, and similar effects can be expected.

[0047]

As described above, according to the present invention, a concave portion that bends toward the center is provided on the outer peripheral surface of the opening end of each unit case, and the welding is performed at the opening edge of each unit case so as to project to the outer peripheral side. Since each piece is provided and both the welding pieces are melted to weld the abutting portion, both welding pieces protrude from the central portion of the groove formed by the both recesses. For this reason, the melted both welding pieces are stored in the groove portion and solidified, so that the welding state can be stabilized and a large welding strength can be obtained. Further, since the melted welding piece does not diffuse to the outside of the groove portion, the appearance of the welding portion can be improved.

According to the present invention, since the protruding lengths of the respective welding pieces are made different from each other, the welding piece having the longer protruding length first comes into contact with the heating body, and the welding piece having the shorter protruding length is first contacted. The welding pieces are melted so as to wrap them, and then both the welding pieces are melted. Therefore, both welding pieces are melted and solidified in a mixed state, and the welding state can be stabilized not only in the case of the same type of plastic but also in the case of welding different types of plastics.

Further, according to the present invention, since each welding piece is provided with the concavo-convex portion which engages with each other when the end edges of the unit case openings are abutted, the concavo-convex portion which engages with each other causes
When the two welding pieces are melted, they are mixed with each other, and the welding state can be further stabilized.

According to the present invention, a plurality of welding pieces are provided at intervals in the circumferential direction, and when the opening edges of both unit cases are butted, the other unit is placed between the welding pieces of one unit case. Since the welding pieces of the case are fitted and locked, this fitting and locking allows the two welding pieces to mesh with each other when they are melted, thereby further stabilizing the welding state.

According to the present invention, the heating element comprises a plurality of plate-shaped bases each having a gutter shape whose front end surface is concavely curved in the plate thickness direction, and heat generation provided on the front end surface of each base. Since it is composed of a body and each base is divided into a plurality of groups and brought into contact with the abutting portion for each group,
Even if the outer peripheral shape of the butted portion is complicated, it is possible to stabilize the welding state and obtain a large welding strength. Further, the gutter-shaped tip end surface of each substrate can prevent the spread of the melted plastic and improve the finished shape of the welded portion.

Further, according to the present invention, since the temperature compensating mechanism for equalizing the temperature in the longitudinal direction of the heating element is provided at the central portion in the plate width direction of each base, when a long heating element is used. Even if there is, the temperature distribution of the heating element can be made uniform.

Further, in the present invention, each heating element is provided with a main power supply circuit and a plurality of temperature detection power supply circuits, and each temperature detection power supply circuit is also used as an auxiliary power supply circuit for temperature compensation. Therefore, the temperature distribution of the heating element can be made uniform, and the set temperature can be accurately maintained.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing a welding device for a case according to a first embodiment of the present invention.

FIG. 2 is a plan view of FIG.

3A to 3C are explanatory views sequentially showing a welding operation of a butt portion using a heating body according to a procedure.

4 (a) to 4 (c) are explanatory views sequentially showing a welding operation of a butt portion in accordance with a procedure in the second embodiment of the present invention.

FIG. 5 is a configuration diagram of a butted portion according to a third embodiment of the present invention as viewed from the outer peripheral side.

FIG. 6 is a configuration diagram of a butt portion according to a fourth embodiment of the present invention viewed from an outer peripheral side.

FIG. 7 is a view corresponding to FIG. 6 showing a state before butting.

FIG. 8 is a view, corresponding to FIG. 2, showing a fifth embodiment of the present invention.

FIG. 9 is a configuration diagram showing a sixth embodiment of the present invention.

10 is a configuration diagram showing an example of each power supply of FIG.

[Explanation of symbols]

 1 Battery Case 1a Upper Case (Unit Case) 1b Lower Case (Unit Case) 2 Heater 3 Grooves 3a, 3b Recesses 4a, 4b Welding Pieces 5a, 5b, 5c, 5d Base 6 Heater 7 Opening (Temperature Compensation Mechanism) 11 Concavo-convex part 21 Main power supply circuit 21a Main power supply 22, 23, 24 Temperature detection power supply circuit 22a, 23b, 24a Temperature detection power supply 25 Power supply 26, 27, 28, 29 Current regulator

Claims (7)

[Claims] 1. A method for welding a case in which opening end edges of a pair of unit cases are butted against each other, and a heating body is brought into contact with the butted portions from the outer peripheral side to weld the butted portions, the method comprising: A concave portion that bends toward the center is provided on the outer peripheral surface of the opening end, and welding pieces that project toward the outer peripheral side are provided on the opening edge of each unit case.These welding pieces are melted to weld the abutting portion. A method for welding a case, comprising: 2. The method for welding a case according to claim 1, wherein the protruding lengths of the welding pieces are different from each other. 3. The case welding according to claim 1, wherein each welding piece has an uneven portion that engages with each other when the opening edges of both unit cases are abutted against each other. Method. 4. A plurality of welding pieces are provided at intervals in the circumferential direction, and when the opening edges of both unit cases are abutted,
3. The method for welding a case according to claim 1, wherein the welding piece of the other unit case is fitted and locked between the welding pieces of the one unit case. 5. A welding device for a case, wherein the opening edges of a pair of unit cases are butted against each other, and a heating body is brought into contact with the butted portion from the outer peripheral side to weld the butted portion, wherein the heating body is A plurality of plate-shaped bases each having a gutter shape whose front end surface is concavely curved in the plate thickness direction and a heating element disposed on the front end surface of each base are provided, and each base is a plurality of groups. A welding device for a case, characterized by being divided into groups and contacting the abutting portion for each group. 6. The case welding device according to claim 5, wherein each base has a temperature compensating mechanism for uniformizing the temperature of the heating element in the longitudinal direction at the central portion in the plate width direction. . 7. Each of the heating elements includes a main power supply circuit that energizes in the longitudinal direction of the heating element and a plurality of temperature detection power supply circuits that energize in the width direction at intervals in the longitudinal direction of the heating element. 7. The case welding device according to claim 5, wherein the power supply circuit also serves as an auxiliary power supply circuit for temperature compensation.