JP2009266695A - Manufacturing method of battery, and battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a high-reliability battery prevented in the generation of a sputter in a battery case, and the occurrence of the partial burnout of a power generation element or the like while welding an unwelded case body to an unwelded sealing member by using an energy beam. <P>SOLUTION: This manufacturing method of a battery 1 provided with a power generation element 40 and a metallic battery case 10 includes: an abutting process of making a first welding-planned part 21 of an unwelded case body 20B having an opening 25 and a second welding-planned part 31 of an unwelded sealing member 30B sealing the opening abut on each other; and a welding process of forming the battery case 10 by emitting an energy beam EB from a direction DB orthogonal to an overlapping direction DA. The second welding-planned part includes a projection 34 projecting toward the facing first welding-planned part, and the abutting process brings the projection into press-contact with the first welding-planned part throughout the whole circumference. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery manufacturing method including a battery case formed by welding an unwelded case main body having an opening and an unwelded sealing member that seals the opening, and an assembled battery including a plurality of such batteries. About.

In recent years, with the spread of portable electronic devices such as mobile phones, notebook computers, and video camcorders and vehicles such as hybrid electric vehicles, the demand for batteries used for these driving power sources is increasing.
Among such batteries, there is a battery composed of a battery case formed by welding an unwelded case body having an opening and an unwelded sealing member capable of sealing the opening of the unwelded case body. . The battery case has a form capable of accommodating the power generation element inside thereof.
In this battery, as a welding means for sealing the opening of the unwelded case main body with an unwelded sealing member, for example, an energy beam such as a laser beam is irradiated to a portion where the unwelded sealing member and the unwelded case main body contact each other. Energy beam welding. Therefore, for example, in Patent Document 1, a concave step having substantially the same size as the inner diameter of the square case (unwelded case body) is provided on the square case side in the peripheral portion of the seal plate (unwelded seal member). And a battery in which laser welding is performed by bringing a rectangular case into contact with each other.

JP 11-339737 A

  However, in the battery manufacturing process described in Patent Document 1, when the unwelded case body and the unwelded sealing member are brought into contact with each other due to the dimensional tolerance or distortion of the unwelded case body and the unwelded sealing member, There may be some gaps between them. When this gap is irradiated with an energy beam such as a laser beam, the energy beam may enter the inside of the battery case surrounded by the unwelded case body and the unwelded sealing member through the gap. Then, for example, the energy beam hits a concave step of the unwelded sealing member, and there is a possibility that a problem of generating spatter (metal fine particles) in the battery case may occur. Further, for example, the energy beam may be reflected at the concave step or the inside of the battery case, hit the power generation element (separator, electrode plate), etc., and burn out a part of the separator.

  The present invention has been made in view of such a problem, and while splicing an unwelded case body and an unwelded sealing member using an energy beam, spatter is generated in the battery case and a part of the power generation element is present. An object of the present invention is to provide a highly reliable battery manufacturing method that prevents the occurrence of burning and the like. It is another object of the present invention to provide a highly reliable assembled battery using such a battery.

  The solution is a method for manufacturing a battery comprising a power generation element and a metal battery case in which the power generation element is housed. The power generation element is housed in the battery and has an opening. Of the welding case main body, an annular first welding planned portion located at the periphery of the opening and an unwelded sealing member that seals the opening of the non-welding case main body, the annular facing the first welding planned portion. A contact step of bringing the second welding scheduled portion into contact with each other, and irradiating with an energy beam from a direction perpendicular to the overlapping direction in which the first welding scheduled portion and the second welding scheduled portion overlap each other Welding the first welding planned portion and the second welding planned portion in a state of being made, and welding the unwelded case body and the unwelded sealing member to form the battery case, Above of the unwelded case body At least one of the first welding planned portion and the second welding planned portion of the unwelded sealing member is the opening in the state where the first welding planned portion and the second welding planned portion are opposed to each other. And extending in the circumferential direction to form an annular shape surrounding the opening, and including a protrusion having a shape protruding toward the opposite welding target portion, and the contact step includes the protrusion. This is a method for manufacturing a battery that is press-contacted to the above-mentioned welding planned portion of the other party over the entire circumference.

  In the battery manufacturing method of the present invention, at least one of the first welding scheduled portion of the unwelded case main body and the second welding scheduled portion of the unwelded sealing member has the above-described protrusion. . And in a contact process, this protrusion part is press-contacted to the other party planned welding part over the perimeter. That is, there is no gap around the entire circumference between the protruding portion and the counterpart welding planned portion.

  For this reason, when an energy beam is irradiated to the 1st welding scheduled part and the 2nd welding scheduled part in the state which contact | abutted at the welding process, between this 1st welding scheduled part and the 2nd welding scheduled part The energy beam is not directly irradiated into the battery case through the generated gap. Thus, the energy beam incident on the inside of the battery case is reflected directly or at various places, hits the battery case or a member in the battery case such as a power generation element (separator, electrode plate), or causes spatter, or It is possible to prevent the occurrence of problems such as burning part of the separator. Thereby, a highly reliable battery can be manufactured.

The battery case may be any battery case that satisfies the above-described requirements. Examples of the battery case include a cylindrical shape, a prismatic shape, and a square plate shape. Moreover, as an opening of an unwelded case main body, when accommodating a power generation element in an unwelded case main body, the insertion port which penetrates this is mentioned, For example, Other openings, such as an attachment hole of a safety valve, may be sufficient.
Examples of energy beam welding include laser beam welding, electron beam welding, and ion beam welding.
Moreover, as a direction which irradiates an energy beam, what is necessary is just the direction orthogonal to the overlapping direction where a 1st welding plan part and a 2nd welding plan part overlap. For example, among the directions orthogonal to the overlapping direction, the direction orthogonal to the wall surface forming the battery case or an oblique direction may be used.

Moreover, what is necessary is just to satisfy | fill the above-mentioned requirements as a protrusion part. The material forming the ridge portion may be the same material as the unwelded case main body or the unwelded sealing member forming the basis of the ridge portion, and specifically, may be formed integrally.
Further, a different material may be used. However, as described above, generally, dimensional tolerance and distortion occur in the unwelded case body and the unwelded sealing member. When trying to contact the first weld planned portion of the unwelded case body and the second weld planned portion of the unwelded sealing member, it is easily deformed such as being crushed at a site where pressure has increased, The first welding scheduled portion and the second welding scheduled portion may be made of a material softer than the unwelded case main body or the unwelded sealing member that forms the basis of the protruding portion so that the first welding scheduled portion and the second welding scheduled portion are easily press-contacted over the entire circumference.
In addition, the protrusions may have a shape that becomes narrower toward the front end in the protruding direction, such as a wedge shape or a hemispherical shape, so that it can be easily deformed when subjected to pressure in the contact process. preferable.
Further, the ridge portion may be a single ring having one ridge, or a double or more ring having two or more ridges.

  Further, in the battery manufacturing method described above, the unwelded sealing member is an annular shape formed along the second welding planned portion inside the annular second welding planned portion, and the second welding is performed. When the planned portion is overlapped with the first weld planned portion of the unwelded case body, an annular projecting wall surface that protrudes in the overlapping direction from the second weld planned portion to the unwelded case body side is provided. It is preferable to use a battery manufacturing method.

In the battery, the unwelded sealing member may be provided with the annular protruding wall surface of the above-described form. This is because the part forming such an annular protruding wall surface plays the role of a rib and has an effect of improving the strength of the unwelded sealing member.
By the way, in the case where the unwelded sealing member has such an annular protruding wall surface, the energy beam passes through the gap formed between the first welding planned portion and the second welding planned portion and the inside of the battery case. When directly incident on the energy beam, the energy beam strikes the annular protruding wall surface at a relatively close distance from the gap. For this reason, the energy beam irradiated portion of the annular protruding wall is melted, and spatter (metal fine particles) is generated, which affects the performance of the battery as a foreign substance, and the separator burns due to contact with high-temperature spatter. It is easy to produce.

However, in the battery manufacturing method according to the present invention, as described above, at least one of the first welding scheduled portion and the second welding scheduled portion is provided with a protruding portion, and in the contacting step, all of the protruding portion is provided. Since it is press-contacted to the other part of the planned welding area, there is no gap between the first welding planned part and the second welding planned part, and the energy beam is directly irradiated to the inside of the battery case. There is no.
For this reason, even in a battery using an unwelded sealing member having an annular protruding wall surface, it is possible to reliably prevent problems and manufacture a highly reliable battery.

  In addition, as the annular projecting wall surface, for example, on the inner side of the annular second planned welding portion, the side surface facing the second welding planned portion side among the cylindrical wall-shaped portions projecting in the overlapping direction, The side surface which faced the 2nd scheduled welding part is mentioned among the site | parts which make the site | part inside the 2 scheduled welding part protrude in convex shape in the overlapping direction.

  Furthermore, in any one of the above-described battery manufacturing methods, the unwelded sealing member is a plate-shaped unwelded sealing plate, and the unwelded sealing plate is attached to the second welding scheduled portion thereof. A method for manufacturing a battery having a protrusion is preferable.

In the battery manufacturing method of the present invention, the unwelded sealing plate has a protrusion on the second welding scheduled portion. Compared to providing a ridge on the first unwelded portion of the unwelded case main body that houses the power generation element, the ridge is provided on the second welding scheduled portion of the plate-like unwelded sealing plate. The protrusions can be formed relatively easily using a press or the like, and the ridges can be formed with high accuracy.
Therefore, an inexpensive and more reliable battery can be manufactured.

  Furthermore, another solution is an assembled battery comprising a plurality of batteries having the same configuration, the battery case including the power generation element and a metal battery case housing the power generation element therein, wherein the battery case of the battery Each of which includes the power generation element therein, and among the unwelded case main body having an opening, an annular first welding planned portion positioned at the periphery of the opening and the opening of the unwelded case main body. Among the unwelded sealing members that seal the ring, the annular second welding scheduled portion facing the first welding scheduled portion is orthogonal to the overlapping direction in which the first welding scheduled portion and the second welding scheduled portion overlap. An energy beam is irradiated from the direction to melt them, and the unwelded case main body and the unwelded sealing member are welded. The unwelded sealing member used for the battery case is an annular second weld Inside the planned part, When the second welding scheduled portion is overlapped with the first welding scheduled portion of the unwelded case body in an annular shape formed along the second welding planned portion, the unwelded portion is more than the second welding planned portion. The battery case has an annular protruding wall surface that protrudes to the case body side, and the annular protruding wall surface of the battery case is an assembled battery that maintains the surface state before welding over the entire circumference.

  The assembled battery of the present invention is composed of a plurality of batteries having the same form. Moreover, in any of these batteries, the annular protruding wall surface of the battery case maintains the surface state before welding over the entire circumference. That is, in this battery group, in the welding by the energy beam, the energy beam is directly irradiated to the annular projecting wall inside the battery case through the gap generated between the first welding scheduled portion and the second welding scheduled portion. It is composed only of batteries that did not exist. For this reason, it is possible to prevent problems such as spatter that is likely to occur when the energy beam is directly irradiated to the annular projecting wall surface inside the battery case, and even if it is viewed as an individual battery, Further, the assembled battery as a whole is a highly reliable assembled battery.

In addition, as an assembled battery, the assembled battery which connected each battery in series, parallel, series-parallel, parallel series, etc. is mentioned.
In addition, the annular protruding wall surface of the battery case maintains the surface state before welding means that the surface of the annular protruding wall surface is welded in a state where there is no trace irradiated with an energy beam, for example, a trace melted by irradiation. Say that you hold on.

(Embodiment 1)
Next, Embodiment 1 of the present invention will be described with reference to the drawings.
First, the battery 1 according to the first embodiment will be described. 1 is a perspective view of the battery 1, FIG. 2 is a partially cutaway sectional view of the battery 1, and FIG. 3 is a sectional view of the battery 1 (cross section AA in FIG. 2).
The battery 1 according to the first embodiment is a wound lithium ion secondary battery including a rectangular box-shaped battery case 10 and a power generation element 40.

  Among them, the power generating element 40 is formed by winding a belt-like positive electrode plate 41 and a negative electrode plate 42 into a flat shape via a belt-like separator 43 made of polyethylene (see FIG. 3). The positive electrode plate 41 and the negative electrode plate 42 of the power generation element 40 are joined to a plate-like positive electrode current collecting member 71 or a negative electrode current collector member 72 bent in a crank shape, respectively. Specifically, as shown in FIG. 2, in the positive electrode plate 41, approximately half (upward in FIG. 2) of the positive electrode lead portion 41f that protrudes from the first end 43A of the separator 43 and is made of aluminum foil is the positive electrode. The current collecting member 71 is in close contact and welded. Similarly, the negative electrode lead portion 42 f of the negative electrode plate 42 is welded to the negative electrode current collecting member 72.

The positive electrode plate 41 carries a positive electrode active material layer (not shown) on both surfaces of the strip-shaped aluminum foil, leaving a positive electrode lead portion 41f along one side. This positive electrode active material layer includes lithium nickel oxide (LiNiO ₂ ) as a positive electrode active material, acetylene black as a conductive agent, and polytetrafluoroethylene (PTFE) and carboxymethyl cellulose (CMC) as a binder. These mass ratios in the positive electrode active material layer are 90 wt% for LiNiO ₂ , 7 wt% for acetylene black, 1 wt% for PTFE, and 2 wt% for CMC.
Moreover, the negative electrode plate 42 carries the negative electrode active material layer which is not shown in figure on both surfaces, leaving the negative electrode lead part 42f along one side among strip | belt-shaped copper foil. This negative electrode active material layer contains graphite and a binder.

Further, the electrolytic solution (not shown), ethylene carbonate (EC) and ethyl methyl carbonate (EMC), EC volume ratio: EMC = 3: a mixed organic solvent 7 adjusted to, by adding LiPF ₆ as a solute, lithium It is an organic electrolyte having a concentration of 1 mol / l of ions.

The battery case 10 is formed by welding a battery case body 20 made of aluminum and a sealing plate 30 by laser beam welding described later. Specifically, the battery case body 20 and the sealing plate 30 are welded through the welded portion PX over the entire circumference of the battery case 10.
Among these, the bottomed rectangular box-shaped battery case body 20 accommodates the above-described power generation element 40 and an electrolyte (not shown) therein. The battery case main body 20 has an opening 25 that opens upward in FIG. 2. Note that an insulating film made of resin (not shown) is attached to the entire inner surface of the battery case body 20 to prevent leakage.

  Further, the sealing plate 30 has a rectangular plate shape in plan view, but as shown in FIGS. 2 and 3, the periphery thereof is bent in a crank shape over the entire periphery, and the periphery 31 and the inside of the battery case 10 from now on. And an insertion portion 35 that protrudes in a convex shape and is inserted into the opening 25 of the battery case body 20. In the sealing plate 30, the insertion portion 35 plays a role of a rib with respect to the peripheral edge portion 31, so that the strength of the sealing plate 30 is high.

The sealing plate 30 seals the opening 25 of the battery case body 20. Further, a positive electrode current collecting member 71 and a negative electrode current collecting member 72 connected to the power generation element 40 pass through the sealing plate 30. Specifically, the positive electrode terminal portion 71A and the negative electrode terminal portion 72A located at the respective tips of the positive electrode current collecting member 71 and the negative electrode current collecting member 72 are the first facing the upper side in FIG. Projecting from the surface 37. A resin insulating member 75 is interposed between the positive electrode terminal portion 71A (the positive electrode current collecting member 71) and the negative electrode terminal portion 72A (the negative electrode current collecting member 72) and the sealing plate 30 to insulate each other. Has been.
A rectangular plate-shaped safety valve 77 is sealed to the sealing plate 30.

The peripheral edge 31 of the sealing plate 30 is joined to the opening end 21 surrounding the opening 25 of the battery case body 20 by welding over the entire circumference (see FIGS. 2 and 3).
The insertion portion 35 protrudes from the peripheral edge portion 31 in the first direction DA (the depth direction of the opening 25 of the battery case body 20, downward in FIGS. 2 and 3). It is an annular projecting wall surface 36 extending in one direction DA (see FIG. 2). This annular protruding wall surface 36 has no trace (for example, melted mark) irradiated with the laser beam over the entire circumference, and the surface state of the annular protruding wall surface 36 in the sealing plate before welding (unwelded sealing plate 30B described later) Even after welding, it is held as it is. This is because the annular protruding wall surface 36 of the first embodiment is not directly irradiated with the laser beam during welding, and an unwelded case body 20B and an unwelded sealing plate 30B, which will be described later, are formed during welding. This is because there was no gap between them.

Next, a method for manufacturing the battery 1 according to the first embodiment will be described with reference to the drawings.
First, the contact process in the manufacturing method of the battery 1 will be described. An unwelded case body 20B made of aluminum having an outer dimension of 150 × 30 × 100 mm and a plate thickness of 1 mm and a rectangular box shape, and an unwelded seal made of aluminum having an outer dimension of 150 × 30 × 1.5 mm and a plate thickness of 1 mm A plate 30B is prepared (see FIG. 6). Among these, the unwelded case main body 20B has an annular opening end portion 21 that surrounds an opening 25 that opens in a direction opposite to the first direction DA (upward in FIG. 4). In addition, the opening edge part 21 is located in the periphery of the opening 25, and is a 1st scheduled welding part welded to the unwelded sealing board 30B (peripheral part 31 mentioned later) in the welding process mentioned later.

Further, the unwelded sealing plate 30B has a rectangular plate shape in plan view, but as shown in FIG. 4, its peripheral edge is bent into a crank shape over the entire circumference, and the annular peripheral portion 31 and the battery case 10 from now on. It has an insertion portion 35 that protrudes inwardly and is inserted into the opening 25 of the unwelded case body 20B described above.
The unwelded sealing plate 30B is penetrated by a positive current collector 71 and a negative current collector 72 connected to the power generation element 40. That is, the unwelded sealing plate 30 </ b> B is formed by winding the positive electrode plate 41 and the negative electrode plate 42 in advance via the separator 43 and is welded to the positive electrode current collector 71 and the negative electrode current collector 72, respectively. Holding. A resin insulating member 75 is interposed between the positive electrode current collecting member 71 and the negative electrode current collecting member 72 and the unwelded sealing plate 30B, and is insulated from each other.

The insertion portion 35 of the unwelded sealing plate 30B protrudes from the peripheral portion 31 in the first direction DA (downward in FIG. 4), and the periphery of the insertion portion 35 is an annular annular protrusion extending in the first direction DA. It is a wall surface 36 (see FIG. 4). Specifically, the annular projecting wall surface 36 is located inside the annular peripheral edge portion 31 and is an annular shape formed along the peripheral edge portion 31. And when the peripheral part 31 is piled up on the opening end part 21 of the unwelded case main body 20B, it has the form which protrudes in the 1st direction DA from the peripheral part 31 to the unwelded case main body 20B side.
In this unwelded sealing plate 30B, the insertion portion 35 (annular projecting wall surface 36) plays a role of a rib with respect to the peripheral portion 31, so the strength of the unwelded sealing plate 30B is high.

Further, the peripheral edge 31 is a second welding scheduled portion that is arranged to face the open end 21 of the unwelded case main body 20 </ b> B and is welded to the open end 21. The peripheral edge 31 is an annular peripheral weld main body 33 that melts and becomes the main body of welding during welding, and an annular extending along the peripheral weld main body 33, and the peripheral weld 31 is a first direction from the peripheral weld main body 33. It includes a lid-side ridge 34 that protrudes toward the DA and has an apex formed at an acute angle (see FIGS. 5 and 6). In the welding process to be described later, the peripheral edge portion 31 is melted by the laser beam EB and mixed with each other together with the open end portion 21 of the unwelded case main body 20B to form a welded portion PX.
In addition, the lid-side protrusion 34 has an annular shape that extends in the circumferential direction of the opening 25 of the unwelded case body 20B and surrounds the opening 25 in a state where the opening end 21 and the peripheral edge 31 shown in FIG. And has a form protruding toward the open end 21.

  Compared with the case where a ridge is provided at the open end 21 of the unwelded case main body 20B, the use of a press or the like is to provide the lid-side ridge 34 on the peripheral edge 31 of the plate-like unwelded sealing plate 30B. The lid-side ridge 34 can be formed on the unwelded sealing plate 30B with high accuracy. For this reason, it is possible to manufacture a battery 1 that is inexpensive and more reliable.

  In the contact process of the first embodiment, the unwelded sealing plate 30B is brought into contact with the unwelded case main body 20B described above. Specifically, first, an unwelded case body 20B is prepared as shown in FIG. The open end 21 of the unwelded case main body 20B faces in the direction opposite to the first direction DA. Then, the unwelded sealing plate 30B is moved along the first direction DA while the power generation element 40 held by the unwelded sealing plate 30B is housed in the unwelded case body 20B through the opening 25 (FIGS. 4 and 5). reference). In this way, the unwelded sealing plate 30B is moved so that the open end 21 of the unwelded case body 20B and the peripheral edge 31 of the unwelded sealing plate 30B are brought into contact with each other (see FIG. 7). That is, the opening end 21 and the lid-side ridge 34 that protrudes in the first direction DA from the peripheral edge 31 are brought into contact with each other.

  In this contact step, after the contact, the lid-side ridge 34 is pressed against the open end 21 over the entire circumference. Specifically, as shown in FIG. 8, using the pressing jigs PM, PM that can be pressed along the first direction DA, the lid of the unwelded sealing plate 30B is formed on the open end 21 of the unwelded case body 20B. The side protrusion 34 is pressed toward the first direction DA. As a result, the lid-side ridge 34 of the peripheral edge 31 is deformed while being in contact with the opening end 21 to be a deformed part 34P, and a gap is formed between the open end 21 and the deformed part 34P of the peripheral edge 31. Will not occur.

  While maintaining such a state, the process proceeds to the welding process. In the welding process of the first embodiment, as shown in FIGS. 8 and 9, the second direction is a direction orthogonal to the first direction DA, specifically, a direction orthogonal to each outer surface of the unwelded case body 20B. The laser beam EB is irradiated from DB (in FIGS. 8 and 9, from right to left). At this time, the pressing jigs PM and PM hold the unwelded case main body 20B and the unwelded sealing plate 30B in a state of being sandwiched between the unwelded case body 20B and the unwelded sealing plate 30B, and press the deformed portion 34P against the opening end 21. Let me. Then, the open end 21 and the peripheral portion 31 (the deformed portion 34P and the peripheral welded main body portion 33) in contact with each other are melted by the laser beam EB, and the unwelded case main body 20B and the unwelded sealing member 30B are welded. The battery case 10 is formed by welding through PX.

  Then, in the above-described welding process, the laser beam EB is directly irradiated to the inside of the battery case 10 through a gap formed between the opening end portion 21 and the peripheral portion 31 (the deformed portion 34P and the peripheral weld main body portion 33). There is nothing to do.

Therefore, the inventors have melted the inside of the battery case 10 (the battery having the power generation element 40 and before injecting the electrolytic solution) and burned the separator, with respect to the battery case 10 formed by performing the contact process and the welding process described above. In order to verify the presence or absence of spattering, the battery case 10 was disassembled.
In addition, as a comparative example, a similar disassembly investigation was also performed on a battery case B1 formed using an unwelded sealing plate that is different only in that the lid-side protrusion is not formed as shown in FIG. The battery case 10 and the battery case B1 were respectively disassembled with a sample number N = 10, and visually confirmed whether there was a melting point on the inner surface of the battery case, whether the separator was burnt, or whether there was sputtering in the battery case. Each was confirmed. Table 1 shows the results of investigation on the battery case 10 and the battery case B1.
In addition, it is thought that the burn of the separator occurred because the laser beam directly incident on the battery case was reflected on the inner surface of the battery case and applied to the separator. Further, it is considered that the spatter is caused by the laser beam being irradiated on the inner surface of the battery case and melting this portion.

According to Table 1, in the case of melting and burning of the separator, in the battery case B1, melting of the inner surface of the battery case or burning of the separator was confirmed for 7 out of 10 points. On the other hand, in the battery case 10, neither was confirmed.
Further, looking at the spatter column, in battery case B1, the presence of spatter in the battery case was confirmed for 7 out of 10 points. On the other hand, none was confirmed in the battery case 10.
From this result, in the battery case 10 according to the first embodiment, the lid-side protrusion 34 is provided on the unwelded sealing plate 30B, and this is press-contacted to the unwelded case main body 20B without any gaps. It was found that none of the inner surface melted, the burnt of the separator 43 and the spatter in the battery case 10 occurred.

  In particular, in the case of the first embodiment, the annular protruding wall surface 36 of the insertion portion 35 in the unwelded sealing plate 30B is located on a linear extension in the traveling direction (second direction DB) of the irradiated laser beam EB ( (See FIG. 9). For this reason, if there is a gap between the unwelded sealing plate 30B and the unwelded case main body 20B, the laser beam EB hits the annular projecting wall surface 36 and is easily melted. On the other hand, in the battery case 10 of the first embodiment, it is possible to reliably prevent the laser beam EB from being applied to the annular projecting wall surface 36, so that the annular projecting wall surface 36 is melted and spatter is generated accordingly. Partial burning can be reliably prevented.

After the above-described welding process, an electrolyte solution (not shown) is injected into the battery case 10 and then the safety valve 77 is sealed to the sealing plate 30. Thus, the battery 1 is completed (see FIGS. 1, 2, and 3).
As described above, a highly reliable battery can be manufactured by the manufacturing method of the battery 1 of the first embodiment.

(Modification 1)
Next, the battery 101 according to the first modification of the present invention will be described with reference to the drawings.
In the manufacturing method of the battery 101 according to the first modification, the protrusions are provided not on the second welding scheduled portion of the unwelded sealing plate but on the first welding scheduled portion of the unwelded case body, as described above. Unlike Embodiment 1, other than that is the same.
Therefore, differences from the first embodiment will be mainly described, and description of similar parts will be omitted or simplified. In addition, about the same part, the same effect is produced. In addition, the same contents are described with the same numbers.

A battery 101 according to the first modification is a wound lithium ion secondary battery including a rectangular box-shaped battery case 110 and a power generation element 40.
A method for manufacturing the battery 101 will be described with reference to the drawings.
First, the contact process in the manufacturing method of the battery 101 will be described. The unwelded sealing plate 130B made of aluminum has a rectangular plate shape in plan view, but as shown in FIG. 4, its peripheral edge is bent into a crank shape over the entire periphery, and the annular peripheral portion 131 and the battery case 10 and an insertion portion 35 protruding in a convex shape toward the inside (see FIGS. 11 and 12). Among these, the peripheral part 131 is a cyclic | annular 2nd welding plan part in this modification 1. FIG. However, unlike Embodiment 1, the peripheral edge portion 131 does not include a lid-side protrusion.

In addition, the rectangular box-shaped unwelded case main body 120B made of aluminum has an annular opening end 121 that surrounds the opening 25 that opens in the reverse direction (upward in FIG. 4) of the first direction DA. The open end 121 is an annular first welding planned portion in the first modification. The opening end 121 has an opening welding main body 123 and an annular shape extending along the opening welding main body 123. The opening end 121 protrudes from the opening welding main body 123 in a direction opposite to the first direction DA. And a case-side ridge 124 having a top formed at an acute angle (see FIGS. 11 and 12). Among these, the opening weld main body 123 is melted by the laser beam EB and mixed with each other together with the peripheral edge 131 of the unwelded sealing plate 130B in the welding process to form a weld PX.
Further, the case-side protrusion 124 has an annular shape that extends in the circumferential direction of the opening 25 of the unwelded case main body 120B and surrounds the opening 25 in a state where the opening end 121 and the peripheral edge 131 shown in FIG. And has a form protruding toward the peripheral edge 131.

  In the contact process of the first modification, the unwelded sealing plate 130B is brought into contact with the unwelded case main body 120B described above. Specifically, as in Embodiment 1, the unwelded sealing plate 130B is moved along the first direction DA (see FIGS. 4 and 11). In this way, the unwelded sealing plate 130B is moved, and the opening end 121 of the unwelded case main body 120B and the peripheral edge 131 of the unwelded sealing plate 130B are brought into contact with each other (see FIG. 13). That is, the peripheral edge 131 and the case-side ridge 124 of the opening end 121 are brought into contact with each other.

  In this contact step, after the contact, as in the first embodiment, the case-side ridge 124 is pressed against the peripheral edge 131 over the entire circumference. As a result, the case-side ridge 124 of the opening end 121 is deformed while being in contact with the peripheral portion 131 to become a deformed portion 124P, and between the peripheral portion 131 and the deformed portion 124P of the open end 121, There is no gap.

  While maintaining such a state, the process proceeds to the welding process as in the first embodiment. In the welding process of the first embodiment, as shown in FIG. 14, the laser beam EB is irradiated from the second direction DB (from the right to the left in the figure). At this time, the pressing jigs PM and PM hold the unwelded case main body 120B and the unwelded sealing plate 130B in a state of being sandwiched between the unwelded case main body 120B and the unwelded sealing plate 130B, and press the deformable portion 124P against the peripheral portion 131. Keep it. The peripheral edge 131 and the open end 121 (the deformed portion 124P and the open welded main body 123) in contact with each other are melted by the laser beam EB, and the unwelded case main body 120B and the unwelded sealing member 130B are welded together. The battery case 110 is formed by welding through PX.

  Then, in the above-described welding process, the laser beam EB is directly irradiated to the inside of the battery case 110 through a gap formed between the peripheral edge portion 131 and the opening end portion 121 (the deformation portion 124P and the opening welding main body portion 123). There is nothing to do.

  In view of this, the inventors examined the above-described battery case 110 (the battery having the power generation element 40 and the battery before injecting the electrolyte solution) in order to verify the melting of the inside, the burning of the separator, and the occurrence of spatter. The battery case 110 was disassembled. Similar to the first embodiment, as a comparative example, the battery case B2 formed using an unwelded case body that differs only in that the case-side protrusion is not formed as shown in FIG. We conducted a survey. Table 2 shows the investigation results of the battery case 110 and the battery case B2.

According to Table 2, when it sees about the column of fusion | melting and a burn of a separator, in battery case B2, the melting of the battery case inner surface or the burn of a separator was confirmed about 7 points | pieces. On the other hand, for any of the battery cases 110, melting of the inner surface of the battery case and burning of the separator were not confirmed. Moreover, in battery case B2, the presence of spatter was confirmed in the battery case for 8 points out of 10. On the other hand, in the spatter column, the presence of spatter in the battery case was not confirmed for any of the battery cases 110.
As a result, in the battery case 110 according to the first modification, the case-side protruding portion 124 is provided on the unwelded case main body 120B, and this is press-contacted to the unwelded sealing plate 130B over the entire circumference without any gaps. It was found that none of the inner surface melting, scoring of the separator 43, and spattering in the battery case 110 occurred.

After the above-described welding process, an electrolyte (not shown) is injected into the battery case 110, and then the safety valve 77 is sealed to the sealing plate 30. Thus, the battery 101 is completed (see FIGS. 1, 2, and 3).
As described above, a highly reliable battery can be manufactured by the manufacturing method of the battery 101 according to the first modification.

(Embodiment 2)
Next, an assembled battery 200 according to Embodiment 2 of the present invention will be described with reference to FIG. In addition, although description of the part similar to the above-mentioned Embodiment 1 is abbreviate | omitted or simplified, the same effect is produced about the same part. In addition, the same contents are described with the same numbers.

The assembled battery 200 according to the second embodiment includes the above-described battery 1 (or battery 101), that is, the power generation element 40, and a rectangular box-shaped aluminum battery case 10 in which the power generation element 40 is housed. A plurality of wound lithium ion secondary batteries are provided. The assembled battery 200 includes a plurality of batteries 1 (or a plurality of batteries 101) housed in an assembled battery case 211. In this assembled battery 200, a plurality of batteries 1 (or a plurality of batteries 101) are bolted to the bus bar 220 using the fastening holes 71AH and 72AH (see FIG. 1) of these terminal portions 71A and 72A. Each battery 1 (or each battery 101) is connected in series with each other.
Further, the battery 1 (or battery 101) included in the assembled battery 200 is the battery described in detail in the first embodiment (or modified embodiment 1).

  For this reason, in the assembled battery 200 of the second embodiment, in any of the plurality of batteries 1 (or batteries 101), the annular protruding wall surface 36 of the battery case 10 (or battery case 110) extends over the entire circumference with the laser beam EB. There is no trace of melting due to, and the surface state before welding is maintained. This is because, as described above, the annular protruding wall surface 36 is not directly irradiated with the laser beam EB during the welding process, and the unwelded case main body 20B (120B) and the unwelded seal are formed during the welding process. This is because there was no gap between the plate 30B (130B).

  That is, the plurality of batteries 1 (101) included in the assembled battery 200 are configured only by batteries in which the laser beam EB is not directly irradiated onto the annular protruding wall surface 36 inside the battery case 10 (110). . For this reason, it is possible to prevent problems such as spatter that is likely to be generated when the laser beam EB is directly applied to the annular projecting wall surface 36 inside the battery case 10 (110) and mixed into the battery case 10 (110). Therefore, both the individual battery 1 (101) and the assembled battery 200 as a whole are highly reliable assembled batteries.

In the above, the present invention has been described according to the first and second embodiments and the first modified embodiment, but the present invention is not limited to the above-described embodiments, and can be appropriately modified and applied without departing from the gist thereof. Needless to say, you can.
For example, in Embodiment 1 and the like, the battery is a lithium ion secondary battery, but the present invention is not limited to the lithium ion secondary battery, and can be applied to any type of battery. Moreover, although it was set as the rectangular box-shaped battery case, it is good also as forms, such as cylindrical, prismatic shape, square plate shape, etc., for example. Moreover, although the opening of the unwelded case body is an insertion port that can be inserted when the power generation element is accommodated in the unwelded case body, for example, a mounting hole of a safety valve may be used as the opening. Furthermore, in Embodiment 1 or the like, the energy beam welding is a laser beam welding. However, for example, an electron beam welding or an ion beam welding may be used.

Moreover, in Embodiment 1 etc., the material of the protrusion part was made into the same material as an unwelded case main body or an unwelded sealing member. However, the protrusion and the unwelded case main body or the unwelded sealing member may be made of different materials. However, in this case, it is preferable that the protrusion is made of a softer material than the unwelded case body or the unwelded sealing member. It is easily deformed, such as being crushed at a site where pressure has been increased, when the first welding planned portion of the unwelded case body and the second welding planned portion of the unwelded sealing member are to be brought into contact with each other. This is because the first welding planned portion and the second welding planned portion can be easily pressed over the entire circumference.
In addition, the protruding portion has a shape that becomes narrower toward the front end side in the protruding direction, that is, a shape in which the apex has an acute angle so that it can be easily deformed when receiving pressure in the contact step. It may be in the shape of a wedge or hemisphere. Furthermore, although it was set as the single annular | circular shape which has one protrusion of the protrusion part, for example, it is good also as a double or more annular | circular shape which has two or more the protrusions.

2 is a perspective view of a battery according to Embodiment 1 and Modification 1. FIG. 2 is a partially broken cross-sectional view of a battery according to Embodiment 1 and Modification 1. FIG. It is an expanded sectional view (AA part of Drawing 2) of a battery concerning Embodiment 1 and modification 1. It is explanatory drawing of the press process of Embodiment 1, and modification 1. FIG. It is sectional drawing (BB part of FIG. 4) of the press process of Embodiment 1. FIG. It is an expanded sectional view (C section of Drawing 5) of the press process of Embodiment 1. It is explanatory drawing of the press process of Embodiment 1. FIG. FIG. 3 is an explanatory diagram of a welding process according to the first embodiment. It is sectional drawing (D section of FIG. 8) of the welding process of Embodiment 1. FIG. It is explanatory drawing of battery case B1, B2 of Embodiment 1, modification 1. FIG. It is sectional drawing (BB part of FIG. 4) of the press process of the deformation | transformation form 1. FIG. It is an expanded sectional view (E section of Drawing 11) of a press process of modification 1. It is explanatory drawing of the press process of the deformation | transformation form 1. FIG. It is explanatory drawing of the welding process of the deformation | transformation form 1. FIG. 4 is an assembled battery according to a second embodiment.

Explanation of symbols

1,101 Battery 10, 110 Battery case 20B, 120B Unwelded case main body 21, 121 Open end (first weld planned portion)
25 Openings 30B, 130B Unwelded sealing plate (unwelded sealing member)
31, 131 Peripheral part (second welding scheduled part)
34 Lid side ridge (ridge)
36 annular projecting wall surface 40 power generation element 124 case side ridge (ridge)
200 Battery pack DA 1st direction (overlapping direction)
DB second direction (direction perpendicular to the overlapping direction)
EB energy beam

Claims (4)

A method of manufacturing a battery comprising a power generation element and a metal battery case containing the power generation element therein,
Of the unwelded case main body having an opening and containing the power generation element therein, an annular first welded portion positioned at the periphery of the opening and an unwelded sealing the opening of the unwelded case main body An abutting step for abutting the annular second welding scheduled portion facing the first welding scheduled portion among the sealing members;
The first welding scheduled portion and the second welding scheduled portion in a state of being in contact with each other by irradiating an energy beam from a direction orthogonal to an overlapping direction in which the first welding scheduled portion and the second welding scheduled portion overlap. Melting and welding the unwelded case body and the unwelded sealing member to form the battery case, and
At least one of the first welding planned portion of the unwelded case body and the second welding planned portion of the unwelded sealing member is:
In a state where the first welding planned portion and the second welding planned portion are opposed to each other, the annular portion extends in the circumferential direction of the opening and surrounds the opening, and projects toward the opposing welding planned portion. Comprising a ridge having a form,
The contact step is
A method for producing a battery, wherein the protruding portion is press-contacted to the mating welded portion over the entire circumference. A battery manufacturing method according to claim 1, comprising:
The unwelded sealing member is
When the second welding planned portion is overlapped with the first welding planned portion of the unwelded case body in an annular shape formed along the second welding planned portion inside the annular second welding planned portion. A battery manufacturing method comprising an annular protruding wall surface protruding in the overlapping direction from the second scheduled welding portion to the unwelded case body side. A method for producing a battery according to claim 1 or claim 2,
The unwelded sealing member is a plate-shaped unwelded sealing plate,
The said unwelded sealing board is a manufacturing method of the battery which has the said protrusion part in the said 2nd welding plan part of self. A battery pack comprising a power generation element and a metal battery case containing the power generation element therein, and comprising a plurality of batteries having the same configuration,
The battery case of the battery
Of the unwelded case main body having an opening and containing the power generation element therein, an annular first welded portion positioned at the periphery of the opening and an unwelded sealing the opening of the unwelded case main body Of the sealing member, an annular second welding scheduled portion facing the first welding planned portion is irradiated with an energy beam from a direction orthogonal to the overlapping direction in which the first welding planned portion and the second welding planned portion overlap. Irradiate, melt these, and weld the unwelded case body and unwelded sealing member,
The unwelded sealing member used in the battery case is
When the second weld planned portion is overlapped with the first weld planned portion of the unwelded case body in an annular shape formed along the second weld planned portion inside the annular second weld planned portion. , Having an annular protruding wall surface in a form protruding to the unwelded case main body side from the second welding scheduled portion,
The assembled battery formed by maintaining the surface state before welding of the annular projecting wall surface of the battery case over the entire circumference.

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