JP2011258501A - Method for manufacturing battery case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a battery case which improves fusion properties of two laminated steel plates.SOLUTION: A peripheral part 3a of a fusion part 3, which is preliminarily bent upward, is inserted into a groove 26 of a roller part 16, and the roller part 16 is rolled along the peripheral part 3a with the roller part 16 pressed against the peripheral part 3a. Then, the peripheral part 3a is curled along the groove 26 in the upward direction that the peripheral part is preliminarily bent and obtains a curvature radius r of the groove 26. In addition, heat of the roller part 16 is transmitted to the fusion part 3, and resin coating a fusion surface 3b is melted. The same operation is repeated using rollers 16' and 16'' in which grooves 26' and 26'', which respectively have different curvature radii, are formed.

Description

  The present invention relates to a method for manufacturing a battery case, and more particularly, to a method for manufacturing a battery case formed by bonding two laminated steel plates.

  A conventional battery case formed by bonding two laminated steel plates is described in Patent Document 1. The laminated steel plate of the battery case is obtained by coating a resin on the surface of a metal core made of aluminum foil in which a recess for accommodating a power generation element is formed. In this battery case, after fusing two laminated steel plates by fusing together the fusion allowance around the recess so that the surfaces coated with the resin overlap each other, Manufactured by bending the periphery.

  Currently, aluminum is the main material for battery cases, but since aluminum is soft, wrinkles are likely to occur during molding, and when the depth of the recess for accommodating the power generation element is increased, the strength is insufficient. Therefore, there was a problem that there was a limit. Therefore, development of stainless steel battery cases is expected.

JP 2001-325925 A

  However, when the battery case made of stainless steel is manufactured by the manufacturing method described in Patent Document 1, the peripheral edge is bent for the purpose of reducing the occupied volume of the fusion allowance after heat-sealing the laminated steel plates, so that the case is more than aluminum. High-strength stainless steel has a problem that the load during bending is large, and when it is bent, a large shearing force is generated on the fusion surface, and the fused portion may be peeled off. However, this problem does not only occur in stainless steel, and even in the case of aluminum, there is a possibility that the same problem occurs.

  This invention was made in order to solve such a problem, and it aims at providing the manufacturing method of the case for batteries which improved the meltability of two laminated steel plates.

The method for manufacturing a battery case according to the present invention is a method for manufacturing a battery case formed by bonding two laminated steel plates, and the laminated steel plate has a recess and a flat fusion around the recess. And the fusion surface, which is one surface of the fusion part, is coated with a resin for heat sealing, and this manufacturing method prepares two laminated steel sheets, A step of superimposing and a step of heat-sealing the fused portions by applying heat to the fused portions while bending the periphery of the fused portion.
The step of heat sealing may be performed by applying heat to the fusion part while bending the periphery of the fusion part in a curl shape and heat-sealing the fusion parts.
The heat sealing step is performed using a bending heat sealing device, and the bending heat sealing device includes a roller portion in which a groove portion having a semicircular cross section is formed along the rotation direction, and heating means for heating the roller portion. The roller portion is rolled along the periphery of the fusion portion while inserting the fusion portion into the groove portion and pressing the roller portion against the fusion portion, and the heating means heats the roller portion to heat the roller portion. When heat is transmitted to the fused part, heat sealing is performed while bending the fused parts.
The bending heat sealing apparatus may include a plurality of the roller portions having different curvature radii of the groove portions.
A step of pre-bending the peripheral edge portion of the fused portion may be included before the heat sealing step. Alternatively, the semicircular shape of the cross section of the groove portion may be eccentric.
You may include the process of pressing the circumference | surroundings of the bent melt | fusion part after the process of heat-sealing.
The laminated steel plate may be stainless steel.

  According to this invention, while bending the peripheral part of the fusion part, heat is applied to the fusion part, the fusion parts are heat-sealed, and the two laminated steel plates are bonded to each other. Is not peeled off by bending, so that the fusion property between the two laminated steel sheets can be improved.

It is a perspective view of the case for batteries manufactured by the manufacturing method concerning an embodiment of this invention. It is sectional drawing along the II-II line of FIG. It is a figure for demonstrating the process which prepares a laminated steel plate and overlaps the fusion surfaces of a fusion | melting part in the manufacturing method of the battery case which concerns on this embodiment. It is a figure which shows the structure of the bending heat seal apparatus used in the manufacturing method of the battery case which concerns on this embodiment. It is a figure for demonstrating the process of heat-sealing fusion | fusion parts, curving the peripheral part of the fusion | melting part of two laminated steel plates in a curl shape in the manufacturing method of the battery case which concerns on this embodiment. It is a figure for demonstrating the pressing process of the peripheral part of the bent melt | fusion part in the manufacturing method of the battery case which concerns on this embodiment. It is a front view which shows the modification of the roller part used in the manufacturing method of the battery case which concerns on this embodiment. It is a perspective view of the upper mold | type of the metal mold | die used in the modification of the manufacturing method of the battery case which concerns on this embodiment. It is a figure for demonstrating the modification of the manufacturing method of the battery case which concerns on this embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view of a battery case manufactured by the manufacturing method according to the embodiment of the present invention. The battery case 1 includes a rectangular accommodating portion 2 for accommodating a power generation element therein, and a flat fusion portion 3 around the accommodating portion 2. The peripheral edge portion 3a of the fused portion 3 has four linear portions including a pair of long side portions 3a1 and 3a1 and a pair of short side portions 3a2 and 3a2 shorter than the long side portion 3a1. One long side 3a1 and both short sides 3a2 and 3a2 are bent in a curled shape.

  As shown in FIG. 2, the battery case 1 is formed by bonding two laminated steel plates 4 and 4 together. The laminated steel plate 4 made of stainless steel is formed with a rectangular recess 5 for forming the accommodating portion 2 at the center, and a flat fused portion 3 is formed around the recess 5. Has been. The fusion surface 3b which is one surface of the fusion part 3 is coated with a heat sealing resin such as polypropylene. The two laminated steel plates 4 and 4 are bonded together by superimposing the respective fusion surfaces 3b on each other and fusing the coated resin.

Next, a method for manufacturing the battery case 1 will be described.
As shown in FIG. 3, a rectangular plate-shaped stainless steel laminated steel sheet 10 is pressed to form a rectangular recess 5 at the center. Thereby, the flat fusion | fusion part 3 is comprised in the circumference | surroundings of the hollow part 5. FIG. At this time, the heat sealing resin such as polypropylene is coated on the fusion surface 3b which is the surface opposite to the side from which the recessed portion 5 projects out of the two surfaces of the fusion part 3. Become. Two laminated steel plates 4 formed in this way are prepared, and the housing portions 2 are constituted by the respective recessed portions 5 so that the fusion surfaces 3b of the respective fusion portions 3 are overlapped with each other. As described above, one long side portion 3a1 and both short side portions 3a2 and 3a2 (see FIG. 1) of the fused portion 3 are bent in a curled shape. One long side portion 3a1 and both short side portions 3a2, 3a2 are bent upward, which is a direction in which the long side portion 3a1 and the short side portions 3a2, 3a2 can be bent. Thereby, a stable curled bending can be performed in a desired direction. In addition, there is also an effect of preventing the laminated laminated steel plates from being displaced when performing curled bending.

  Next, the fusion parts 3 are heat-sealed while the peripheral edge part 3a of the fusion part 3 is bent in a curled shape. For this purpose, a bending heat sealing device 11 shown in FIG. 4 is used. The bending heat sealing device 11 includes a main body portion 12 that controls the operation of the bending heat sealing device 11, an action portion 13 that heat seals the fusion portions 3 while bending the peripheral portion 3a of the fusion portion 3 in a curled shape, And an arm portion 14 that moves the action portion 13 based on the control of the main body portion 12.

  The action portion 13 includes a frame 15 and a roller portion 16 that is rotatably provided on the frame 15. A heater 17 that is a heating unit is embedded in the frame 15, and the heater 17 is connected to a power supply device 18. The frame 15 is provided with a gripped portion 19 so as to protrude upward, and the gripping portion 20 provided at the end of the arm portion 14 grips the gripped portion 19, thereby 13 is moved by the arm portion 14 based on the control of the main body portion 12.

  Furthermore, the frame 15 is provided with two rectangular flat plate portions 15a and 15b in parallel with each other with an interval in the vertical direction. A rotating shaft 21 extending in the vertical direction so as to penetrate the flat plate portions 15a and 15b is fixed by bolts 22 and 23, respectively. A through hole 24 is formed in the rotation center position of the roller portion 16, so that the rotation shaft 21 is inserted into the through hole 24, and the roller portion 16 is a frame that can rotate around the rotation shaft 21. 15 is provided. The roller portion 16 has a bearing 25 into which the rotating shaft 21 can be inserted. Further, a groove portion 26 having a semicircular cross-sectional shape is formed in the roller portion 16 along the rotation direction. Although not shown, a plurality of action parts including roller parts having different semicircular curvature radii (hereinafter simply referred to as “groove radius of curvature”) of the cross section of the groove part are prepared, and the grip part 20 of the frame 15 is Any action part can be gripped in an exchangeable manner. Each action part differs only in the radius of curvature of the groove part formed in the roller part, and all other structures are the same.

Next, the process of heat-sealing the fused portions 3 together while bending the peripheral edge portion 3a of the fused portion 3 into a curl shape using the bending heat sealing device 11 will be described.
First, the grip part 20 of the arm part 14 grips the action part 13 including the roller part 16 in which the groove part 26 having the largest radius of curvature r is formed. Next, the power supply device 18 is activated to supply power to the heater 17 to heat the heater 17. Then, the frame 15 is heated by the heater 17, the heat of the frame 15 is transmitted to the roller unit 16 through the rotating shaft 21 and the bearing 25, and the roller unit 16 is also heated. The roller unit 16 is heated to a temperature necessary for heat sealing.

  When the roller portion 16 is heated to a temperature necessary for heat sealing, the peripheral edge portion 3a of the fused portion 3 bent upward is inserted into the groove portion 26 of the roller portion 16 as shown in FIG. Then, the roller portion 16 is rolled along the peripheral portion 3a while pressing the roller portion 16 against the peripheral portion 3a. Then, the peripheral edge portion 3a is bent in a curl shape along the groove portion 26 toward the pre-bent upward, and has a radius of curvature r of the groove portion 26. At the same time, the heat of the roller part 16 is transmitted to the fusion part 3, so that the resin coated on the fusion surface 3b is melted. Since the resin between the fused portions 3 and 3 is in a melted state while the peripheral edge portion 3a is bent in a curled shape, the welded portion is not peeled off due to the bending of the peripheral edge portion 3a. .

Next, the grip part 20 (see FIG. 4) of the arm part 14 grips the action part having the roller part 16 ′ in which the groove part 26 ′ having the curvature radius r ′ smaller than the curvature radius r of the groove part 26 is formed. . The peripheral portion 3a bent in a curl shape by the roller portion 16 is inserted into the groove portion 26 ′, and the roller portion 16 ′ is rolled along the peripheral portion 3a while pressing the roller portion 16 ′ against the peripheral portion 3a. Then, the peripheral edge 3a has a curvature radius r ′. Similarly, the peripheral portion 3a has the curvature radius r ″ by the roller portion 16 ″ in which the groove portion 26 ″ having the curvature radius r ″ smaller than the curvature radius r ′ of the groove portion 26 ′ is formed. . By reducing the radius of curvature of the roller groove as the curled bending process proceeds, a desired bent shape can be obtained by suppressing the spring back after the process. During the bending of the peripheral edge portion 3a by the roller portions 16 'and 16 ", the heat of the roller portions 16' and 16" is transferred to the fusion portion 3, so that the resin between the fusion portions 3 and 3 is melted. Therefore, the welded portion is not peeled off by the bending of the peripheral edge portion 3a. Then, the bending and heating of the peripheral edge portion 3a by the roller portions 16, 16 ′, 16 ″ are completed, so that the resin between the fusion portions 3 and 3 is solidified, and the fusion portions 3 are fused. The fused portions 3 are heat-sealed while their peripheral portions are bent in a curl shape.
The manufacturing method according to the present invention heat-seals while bending the fused part, so that the fusion effect is excellent even when using high-strength stainless steel laminated steel sheets due to the effect of reducing the processing load by warm working. Sex is obtained. In particular, in austenitic stainless steel such as SUS304, which is easy to work harden, the production of work-induced martensite generated during processing is suppressed due to warm working, which reduces springback after work and wear on work rollers. An effect is obtained.

  Next, as shown in FIG. 6, a normal roller 30 having no groove formed on the surface is rolled along the peripheral edge 3a while being pressed against the peripheral edge 3a bent in a curl shape. Thereby, the peripheral edge part 3a bent in the curl shape is bent toward the vertical wall of the hollow part 5, and the width of the fused part 3 can be reduced. At this time, since the peripheral edge portion 3a is bent in a curl shape and firmly fused, the fused portion is not peeled off by bending.

  In this way, by applying heat to the fusion part 3 while bending the peripheral part 3a of the fusion part 3 in a curl shape, the fusion parts 3 are heat-sealed, and the two laminated steel plates 4 and 4 are bonded together. Since the fused portions 3 and 3 are not peeled off by bending, the fusion property between the two laminated steel plates 4 and 4 can be improved.

  In this embodiment, the peripheral edge portion 3a is preliminarily bent upward in the groove portion 26 so that the peripheral edge portion 3a of the fused portion 3 is surely bent upward and curled. Not what you want. If the peripheral edge 3a is inserted into the groove 26 without pre-bending and the roller 16 is rolled along the peripheral edge 3a, the direction in which the peripheral edge 3a is bent in a curl shape in the groove 26 is either upward or downward. Since this is not known, in this embodiment, in order to determine the bending direction upward, only preliminary bending is performed upward. Therefore, when the direction of bending in the curl shape in the groove portion 26 is set downward, the preliminary bending direction is set downward.

  On the other hand, in the manufacturing method according to the present invention, preliminary bending is not necessarily an indispensable process. As shown in FIG. 7, by using the roller part 37 in which the semicircular cross-sectional shape of the groove part 36 is formed so as to be eccentric upward, the peripheral part inserted into the groove part 36 is reliably bent upward. Become. Although not shown, when a roller part having a groove part eccentric in the semicircular shape of the cross section is used, the peripheral part inserted into the groove part is surely bent downward.

  In this embodiment, three roller portions in which grooves having different curvature radii are formed are used. However, the number of roller portions is not limited to three, and may be appropriately changed depending on the material, size, etc. of battery case 1. it can. The material of the battery case 1 is not limited to stainless steel, and may be any material such as aluminum.

  In this embodiment, the heater 17 heats the frame 15, the heat is transmitted to the roller portion 16 via the rotating shaft 21 and the bearing 25, and the fusion portion 3 is heat-sealed by the heat of the roller portion 16. However, it is not limited to this form. Only the roller portion 16 may be directly heated by any known means. Alternatively, the fused portions 3 may be directly heat-sealed by any known means without heating the roller portion 16 while the roller portion 16 bends the peripheral edge portion 3a of the fused portion 3 into a curl shape.

Further, the curl-shaped bending in the heat sealing step is performed using a mold in which a groove having a semicircular cross section is formed along each side of the fusion part 3 of the battery case 1 instead of a roller. Also good. Of the molds used in this method, the upper mold 41 is shown in FIG. The upper mold 41 is formed with a groove 40 into which one long side 3a1 of the peripheral edge 3a and both short sides 3a2, 3a2 (see FIG. 1) are inserted.

A method using a mold will be described with reference to FIG. After the front end portion of the peripheral edge portion 3a is bent slightly upward, an arbitrary portion of the fused portion 3 is further bent upward at an angle of about 90 ° (preliminary bending step). Next, the fusion part 3 is placed on the lower mold 42 and the upper mold 41 is moved to the lower mold so that the preliminarily bent peripheral edge 3 a is inserted into the groove 40 of the upper mold 41. Press toward 42. Since the heater 17 is embedded in the upper mold 41 and the heater 17 is connected to the power supply device 18, the upper mold 41 is heated to a temperature necessary for heat sealing and pressed toward the lower mold 42. For example, the fusion bonding portions 3 are heat-sealed while the peripheral edge portion 3a is bent in a curl shape in the groove portion 40. After that, the width of the fused part 3 is reduced by rolling the roller 30 along the peripheral part 3a while pressing the roller 30 against the peripheral part 3a in the same manner as described in the embodiment (see FIG. 6). .

  DESCRIPTION OF SYMBOLS 1 Case for batteries, 3 Fusing part, 3a Peripheral part (of a fused part), 3b Fusing surface (of a fused part), 4 Laminated steel plate, 5 Depressed part, 11 Bending heat seal apparatus, 16, 16 ', 16 ", 37 roller part, 17 heater (heating means), 26, 26 ', 26", 36, 40 groove part 41 upper mold, 42 lower mold.

Claims (8)

A method for manufacturing a battery case formed by bonding two laminated steel plates,
The laminated steel sheet includes a depression and a flat fusion part around the depression, and a fusion surface, which is one surface of the fusion part, is coated with a heat sealing resin. ,
The manufacturing method includes:
Preparing the two laminated steel sheets and superimposing the fusion surfaces;
A process for producing a battery case, comprising: a step of applying heat to the fusion part while bending the periphery of the fusion part and heat-sealing the fusion part.   2. The battery according to claim 1, wherein the heat sealing step is performed by applying heat to the fusion part while bending the periphery of the fusion part in a curled shape and heat-sealing the fusion parts. Case manufacturing method. The step of heat sealing is performed using a bending heat sealing device,
The bending heat sealing device
A roller part in which a groove part having a semicircular cross section is formed along the rotation direction;
Heating means for heating the roller part,
The roller part is rolled along the periphery of the fusion part while inserting the fusion part into the groove part and pressing the roller part against the fusion part, and the heating means heats the roller part. 3. The method for manufacturing a battery case according to claim 1, wherein the heat of the roller part is transmitted to the fusion part, whereby the fusion part is heat-sealed while being bent.   The said bending heat seal apparatus is a manufacturing method of the case for batteries of Claim 3 provided with two or more said roller parts from which the curvature radius of the said groove part differs.   The manufacturing method of the case for batteries as described in any one of Claims 1-4 including the process of pre-bending the peripheral part of the said melt | fusion part before the process of heat-sealing.   The manufacturing method of the case for batteries of Claim 3 or 4 with which the semicircle shape of the cross section of the said groove part is eccentric.   The manufacturing method of the case for batteries as described in any one of Claims 1-6 including the process of pressing the circumference | surroundings of the bent said melt | fusion part after the process of heat-sealing.   The method for manufacturing a battery case according to any one of claims 1 to 7, wherein the laminated steel plate is made of stainless steel.

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