JP5974531B2 - Manufacturing method of sealed battery - Google Patents

Description

The present invention relates to a method of manufacturing sealed batteries with a current interrupt device for cutting off the current flowing through the electrode body when the internal pressure of the battery case exceeds the operating pressure.

  2. Description of the Related Art In recent years, chargeable / dischargeable sealed batteries have been used as driving power sources for vehicles such as hybrid vehicles and electric vehicles, and portable electronic devices such as notebook computers and video camcorders. As a sealed battery, a battery is known that includes a current interrupting mechanism that interrupts the current flowing through the electrode body when the internal pressure of the battery case increases due to overcharging or the like and the internal pressure of the battery case exceeds the operating pressure ( For example, see Patent Document 1).

JP 2008-066254 A

  The current interruption mechanism of Patent Document 1 includes a diaphragm and a rupture member (a metal thin film that is a fragile portion). The diaphragm is electrically connected to the external terminal and deforms outward of the battery case when the internal pressure of the battery case increases. The rupture member (metal thin film) is electrically connected to the electrode body and is electrically connected by welding to the diaphragm, and is deformed together with the diaphragm that is deformed as the internal pressure of the battery case increases. When the internal pressure exceeds the operating pressure, the self-breakage cuts off the power supply to the diaphragm.

  By the way, in patent document 1, the diaphragm and the fracture | rupture member (metal thin film) are welded by performing laser spot welding to the fracture | rupture member (metal thin film). However, in spot welding, when one point is welded, distortion occurs in the fracture member (metal thin film) due to welding heat, and this thermal strain may cause a gap between the diaphragm and the fracture member. When a laser beam is applied to the welded portion of the fracture member in a state where a gap is formed between the welded portion of the fractured member (the portion to be spot welded by irradiating the laser beam) and the diaphragm, the fractured member (irradiated with the laser beam) In some cases, there was a perforation in the welded part), resulting in poor welding. This is because the heat capacity is greatly reduced at the relevant portion by separating the welded portion of the breaking member from the diaphragm.

In addition, there is a possibility that sufficient welding strength cannot be obtained only by welding several points between the diaphragm and the fracture member by spot welding.
In addition, to ensure sufficient welding strength, even when the diaphragm and the fracture member are all-around welded, the fracture member is gradually heated while the laser beam is irradiated from the welding start point to the welding end point. As a result, the fracture member may be distorted. Even when a laser beam or the like is irradiated with a gap between the diaphragm and the fractured member due to this thermal strain, a hole is generated in the fractured member (the location irradiated with the laser beam etc.), resulting in poor welding. was there.

The present invention was made in view of such problems, and an object thereof is to provide a manufacturing how a sealed battery capable of suppressing the poor welding the diaphragm and the rupture member.

Includes an outer portion the terminal, and the electrode body, and the battery case for accommodating the electrode body, and a current interrupt device for cutting off the current flowing through the electrode body when the internal pressure of the battery case exceeds the operating pressure, the The current interrupting mechanism is electrically connected to the external terminal, deformed as the internal pressure of the battery case increases, and electrically connected to the electrode body and welded to the diaphragm. Are connected together and deformed together with the diaphragm deforming as the internal pressure of the battery case rises, and when the internal pressure of the battery case exceeds the operating pressure, the self-breakage causes the diaphragm and the electrode body to In the manufacturing method of a sealed battery having a breaking member that cuts off current between the two, the breaking member is welded to the diaphragm by energy beam welding. In the welding process in which the fracture member is welded to the diaphragm by energy beam welding, the energy beam is irradiated to the fracture member in a state where the profile of the energy beam is the shape of the entire weld portion. Therefore, a method for manufacturing a sealed battery in which the entire welded portion is welded simultaneously is preferable.

  In the manufacturing method described above, in the welding process, the fracture member is welded to the diaphragm by energy beam welding. In this welding process, by irradiating the rupture member with the energy beam in a state where the profile of the energy beam (the cross-sectional shape of the energy beam, the shape when the advancing energy beam is viewed from the front) is the shape of the entire welded portion, Weld the entire weld at once. In other words, in the welding process, the entire welded portion is simultaneously welded at the same time by making the profile of the energy beam applied to the fracture member the shape of the entire welded portion. Here, a welding part is a site | part welded to a diaphragm by energy beam welding among fracture | rupture members.

Thus, by welding the entire welded portion at the same time, the occurrence of thermal distortion in the fracture member can be suppressed, and the occurrence of poor welding (perforation) between the diaphragm and the fracture member can be suppressed. .
Examples of the energy beam include a laser beam and an electron beam.

  Furthermore, in the above-described method for manufacturing a sealed battery, in the welding step, it is preferable to use a method for manufacturing a sealed battery in which a profile of the energy beam is made to be the shape of the entire welded portion through a diffractive optical element lens.

  In the manufacturing method described above, by using a diffractive optical element lens (DOE lens), the profile of the energy beam can be appropriately changed to the shape of the entire welded portion (from the solid round shape). Examples of the shape of the entire welded portion include a ring shape or a shape in which a part of the ring is missing (for example, a shape in which a plurality of arcs are arranged on the circumference at equal intervals).

One embodiment of the present invention is a method for manufacturing a sealed battery according to any one of the above, wherein the energy beam is a fiber laser beam .

  By welding the diaphragm and the fracture member with the fiber laser beam, both members can be appropriately welded.

  Further, in any one of the above sealed battery manufacturing methods, the shape of the entire welded portion is a ring shape, and in the welding step, the fracture member is formed with the energy beam profile in the ring shape. It is preferable to use a method for manufacturing a sealed battery in which the energy beam is irradiated.

  In the manufacturing method described above, the entire welded portion has a ring shape. For this reason, in a welding process, an energy beam is irradiated to a fracture member in the state which made the profile of the energy beam into the ring shape. By welding the rupture member to the diaphragm in a ring shape, the diaphragm and the rupture member can be firmly welded as compared to the case of spot welding.

Further, a sealed battery produced by any one of the aforementioned sealed battery production methods is preferred.

  The above-described sealed battery is manufactured by any one of the above-described manufacturing methods. That is, the entire welded portion of the fracture member is collectively welded to the diaphragm at the same time. For this reason, the above-mentioned sealed battery is a sealed battery in which poor welding between the diaphragm and the fracture member is suppressed.

1 is a perspective view of a sealed battery according to an embodiment. It is a longitudinal cross-sectional view of the battery. It is a perspective view of the positive electrode plate of the battery. It is a perspective view of the negative electrode plate of the battery. It is the A section enlarged view of FIG. It is the B section enlarged view of FIG. FIG. 7 is a bottom view of FIG. 6. It is a figure explaining an effect | action of an electric current interruption mechanism. It is a figure explaining the manufacturing method of the sealed battery concerning an embodiment. It is another figure explaining the manufacturing method. It is a figure explaining the welding process of the manufacturing method. It is another figure explaining the welding process. It is another figure explaining the welding process. It is another figure explaining the welding process. It is another figure explaining the manufacturing method of the sealed battery concerning embodiment. It is a figure explaining the manufacturing method of the sealed battery concerning a modification. It is a figure explaining the manufacturing method.

(Embodiment)
Next, embodiments of the present invention will be described with reference to the drawings.
First, the sealed battery 1 according to the present embodiment will be described. As shown in FIGS. 1 and 2, the sealed battery 1 of the present embodiment includes an electrode body 10 and a battery case 80 that houses the electrode body 10. The electrode body 10 is impregnated with the electrolytic solution 50.

  The battery case 80 includes a case main body member 81 and a sealing lid 82 (see FIGS. 1 and 2). The case body member 81 is made of metal and has a rectangular box shape. The sealing lid 82 is made of metal and has a rectangular plate shape. The sealing lid 82 closes the opening of the case body member 81 and is welded to the case body member 81.

  The electrode body 10 is a wound electrode body in which a belt-like positive electrode plate 20 and a negative electrode plate 30 are wound into a flat shape with a belt-like separator (not shown) made of polyethylene interposed therebetween ( (See FIG. 1). As shown in FIG. 3, the positive electrode plate 20 includes a strip-shaped positive electrode current collector foil 28 and positive electrode active material layers 21 and 21 formed on both main surfaces of the positive electrode current collector foil 28. The positive electrode active material layer 21 is a layer containing a positive electrode active material, and is disposed along one long side extending in the longitudinal direction DA of the positive electrode current collector foil 28.

  A portion of the positive electrode plate 20 on which the positive electrode active material layer 21 is applied is referred to as a positive electrode active material layer application portion 20b (see FIG. 3). On the other hand, a portion made only of the positive electrode current collector foil 28 without having the positive electrode active material layer 21 is referred to as a positive electrode active material layer uncoated portion 20c. The positive electrode active material layer uncoated portion 20 c extends in a strip shape in the longitudinal direction DA of the positive electrode plate 20 along the other long side of the positive electrode plate 20. The positive electrode active material layer uncoated portion 20c is wound to form a spiral shape, and is positioned at one end (right end in FIG. 2) in the axial direction (left and right direction in FIG. 2) of the electrode body 10.

  As shown in FIG. 4, the negative electrode plate 30 includes a strip-shaped negative electrode current collector foil 38 and negative electrode active material layers 31 and 31 formed on both main surfaces of the negative electrode current collector foil 38. The negative electrode active material layer 31 is a layer containing a negative electrode active material, and is disposed along one long side extending in the longitudinal direction DA of the negative electrode current collector foil 38.

  A portion of the negative electrode plate 30 where the negative electrode active material layer 31 is coated is referred to as a negative electrode active material layer coating portion 30b (see FIG. 4). On the other hand, a portion made only of the negative electrode current collector foil 38 without having the negative electrode active material layer 31 is referred to as a negative electrode active material layer uncoated portion 30c. The negative electrode active material layer uncoated portion 30 c extends in a strip shape in the longitudinal direction DA of the negative electrode plate 30 along the other long side of the negative electrode plate 30. The negative electrode active material layer uncoated portion 30c is wound to form a spiral shape, and is positioned at one end (left end in FIG. 2) in the axial direction (left and right direction in FIG. 2) of the electrode body 10.

  The positive electrode active material layer uncoated portion 20c of the positive electrode plate 20 in the electrode body 10 is electrically connected by welding the positive electrode terminal structure 60 (see FIG. 2). The positive terminal structure 60 has a positive external terminal member 68 located outside the battery case 80. The negative electrode active material layer uncoated portion 30c of the negative electrode plate 30 is electrically connected by welding the negative electrode terminal structure 70. The negative electrode terminal structure 70 has a negative electrode external terminal 78 located outside the battery case 80.

  The positive electrode terminal structure 60 includes a current interruption mechanism 62. The current interruption mechanism 62 is a mechanism that interrupts the current flowing through the electrode body 10 when the internal pressure of the battery case 80 exceeds the operating pressure. The current interrupt mechanism 62 will be described in detail later.

The negative electrode terminal structure 70 includes a negative electrode internal terminal member 71, a negative electrode external terminal member 78, and a gasket 79 (see FIG. 2).
The negative electrode internal terminal member 71 is made of copper and is mainly located inside the battery case 80. The negative electrode internal terminal member 71 is joined to the negative electrode active material layer uncoated portion 30 c of the negative electrode plate 30 in the battery case 80, and penetrates the sealing lid 82 of the battery case 80 to form a negative electrode external terminal member. 78 and the gasket 79 are caulked to the sealing lid 82 and are electrically connected to the negative external terminal member 78.

  The negative electrode external terminal member 78 is made of copper, has a shape bent in a crank shape, and is located outside the battery case 80. The negative external terminal member 78 has a through hole 78H on the front end side thereof for fastening a bus bar or the like with a bolt. The gasket 79 is made of an electrically insulating resin, and is interposed between the negative electrode external terminal member 78 and the negative electrode internal terminal member 71 and the battery case 80 to electrically insulate them.

  On the other hand, the positive terminal structure 60 includes a positive internal terminal structure 61, a positive external terminal member 68, and a gasket 69 (see FIG. 2). The positive electrode internal terminal structure 61 is mainly located inside the battery case 80. The positive electrode internal terminal structure 61 includes a current interruption mechanism 62.

  The positive external terminal member 68 is made of aluminum, has a shape bent in a crank shape, and is positioned outside the battery case 80. The positive external terminal member 68 has a through hole 68H on the front end side thereof for fastening a bus bar or the like with a bolt. The gasket 69 is made of an electrically insulating resin, and is interposed between the positive electrode external terminal member 68 and the positive electrode internal terminal structure 61 and the battery case 80 to electrically insulate them.

  2 and 5, the positive electrode internal terminal structure 61 includes a positive electrode current collecting terminal member 63, an enclosing member 66, a flat plate diaphragm 64, a rectangular concave relay member 65, and a caulking member. 67. The positive electrode current collecting terminal member 63, the diaphragm 64, the relay member 65, and the caulking member 67 are all made of aluminum. The surrounding member 66 is made of an electrically insulating resin and surrounds the breaking member 63X of the positive electrode current collecting terminal member 63.

  The caulking member 67 is caulked and deformed through the through hole 82H of the sealing lid 82, and couples the relay member 65, the positive external terminal member 68, and the gasket 69 to the sealing lid 82 (see FIG. 5). Through the caulking member 67, the relay member 65 and the positive external terminal member 68 are electrically connected. Further, the diaphragm 64 connected to the relay member 65 is electrically connected to the positive external terminal member 68. In the present embodiment, the positive external terminal member 68 corresponds to an “external terminal” recited in the claims.

  Further, as shown in FIG. 9, the positive electrode current collecting terminal member 63 includes a rectangular plate-like breaking member 63X and an elongated plate-like current collecting connection member 63Y extending downward from the breaking member 63X. Formed. Among these, the current collection connection member 63Y is joined to the positive electrode active material layer uncoated portion 20c of the positive electrode plate 20 (see FIG. 2). Thereby, the breaking member 63X is electrically connected to the electrode body 10 (specifically, the positive electrode plate 20). The breaking member 63X is formed with a through hole 63G that penetrates the central portion of the breaking member 63X and two through holes 63H and 63H located on both sides of the through hole 63G.

  Further, the breaking member 63X has a welded portion 63F welded to the diaphragm 64 at the position of the peripheral edge of the through hole 63G (see FIGS. 6 and 9). The entire shape of the welded portion 63F is a ring shape along the periphery of the through hole 63G. Furthermore, a ring-shaped notch 63E is formed in the fracture member 63X at a position radially outside the welded portion 63F (see FIG. 6). The notch 63E is a fragile portion (a rupture portion) in the rupture member 63X.

  The surrounding member 66 includes a plate-like insulating resin member 66A and a plate-like insulating resin member 66B (see FIG. 5). The surrounding member 66 is formed with a through hole 66G penetrating the central portion of the surrounding member 66 and two through holes 66H and 66H located on both sides of the through hole 66G.

  As shown in FIG. 10, when the breaking member 63X is surrounded by the surrounding member 66, the through hole 63H of the breaking member 63X and the through hole 66H of the surrounding member 66 overlap, and further, the surrounding hole 63G and the surrounding hole 63G of the breaking member 63X are enclosed. The through hole 66G of the member 66 overlaps. Furthermore, the welded portion 63F and the cutout portion 63E of the breaking member 63X are exposed in the through hole 66G of the surrounding member 66 (see FIGS. 6, 10, and 13).

  In addition, the diaphragm 64 has a protruding portion 64 </ b> A that protrudes toward the breaking member 63 </ b> X side of the positive electrode current collecting terminal member 63 at the center position thereof. Further, the diaphragm 64 is annular, has a U-shaped cross section, and has an annular bent portion 64D positioned on the radially outer side of the protruding portion 64A (see FIGS. 5 and 15). A portion of the diaphragm 64 surrounded by the annular bent portion 64D (a portion including the protruding portion 64A) can be deformed outward (upward in FIG. 5) of the battery case 80 by deformation of the annular bent portion 64D. Yes.

  The diaphragm 64 is welded with a breaking member 63X. Specifically, as shown in FIG. 6, the welded portion 63 </ b> F of the fracture member 63 </ b> X is welded to the protruding portion 64 </ b> A of the diaphragm 64. More specifically, as shown in FIG. 7, the welded portion 63F of the breaking member 63X has a ring shape (annular shape), and the breaking member 63X and the diaphragm 64 are welded in a ring shape. Thereby, the breaking member 63X and the diaphragm 64 are electrically connected. 6 and 7, a portion where the welded portion 63 </ b> F of the fracture member 63 </ b> X and the protruding portion 64 </ b> A of the diaphragm 64 are welded is indicated by cross hatching as a welding conduction portion W.

  Further, the relay member 65 is airtightly joined to the peripheral edge portion 64E of the diaphragm 64 at the peripheral edge portion 65E. Thus, a space C is formed by the relay member 65, the diaphragm 64, and the caulking member 67 (see FIG. 5). In the present embodiment, the space C communicates with the outside of the battery case 80 through the through hole 67H of the caulking member 67, so that the air pressure in the space C is atmospheric pressure.

  In the sealed battery 1 according to the present embodiment, the positive current collecting terminal member 63, the diaphragm 64, the relay member 65, and the surrounding member 66 of the positive electrode internal terminal structure 61 described above constitute the current interruption mechanism 62. (See FIG. 2). The current interruption mechanism 62 interrupts the current flowing through the electrode body 10 when the internal pressure of the battery case 80 exceeds the operating pressure.

  Specifically, for example, when the internal pressure of the battery case 80 increases due to overcharging of the sealed battery 1 and becomes equal to or higher than the operating pressure (for example, 750 kPa), the current flowing through the electrode body 10 is as follows. Cut off.

  As shown in FIG. 5, the diaphragm 64 has a through hole 66 </ b> H, 66 </ b> H of the surrounding member 66, a through hole 66 </ b> G of the surrounding member 66, and a through hole 63 </ b> G of the breaking member 63 </ b> X. The internal pressure F of the battery case 80 is applied. Then, as the internal pressure F of the battery case 80 increases, the diaphragm 64 is deformed outward (upward in FIG. 5) due to a pressure difference with the space C. At this time, of the breaking member 63X welded to the protruding portion 64A of the diaphragm 64, a portion exposed in the through hole 66G of the surrounding member 66 (a portion including the welded portion 63F and the notch portion 63E) is also included. Together with the protrusion 64A of the diaphragm 64, the battery case 80 is deformed outward (upward in FIG. 5).

  When the internal pressure F of the battery case 80 exceeds a predetermined operating pressure, as shown in FIG. 8, the breaking member 63X breaks at the position of the notch 63E, and the diaphragm 64 and the positive current collecting terminal member 63 are separated. It is. Thereby, the electricity supply between the diaphragm 64 and the electrode body 10 is interrupted. Specifically, the current flowing through the electrode body 10 is cut off through the path of (positive electrode external terminal member 68) → (caulking member 67) → (relay member 65) → (diaphragm 64) → (positive electrode current collecting terminal member 63). . Thereby, the charge (overcharge) of the sealed battery 1 is stopped.

Next, a method for manufacturing a sealed battery according to the embodiment will be described with reference to the drawings.
First, the positive electrode plate 20 and the negative electrode plate 30 are each produced by a known method. Then, a separator (not shown) is interposed between the positive electrode plate 20 and the negative electrode plate 30, and these are wound to form a flat wound electrode body 10 (see FIG. 1).

  Moreover, the positive electrode current collection terminal member 63 (refer FIG. 9) is prepared. And as shown in FIG. 10, the fracture | rupture member 63X of the positive electrode current collection terminal member 63 is surrounded by the surrounding member 66 which consists of an insulating resin member. Specifically, the breaking member 63X of the positive electrode current collecting terminal member 63 is sandwiched between the plate-like insulating resin member 66A and the insulating resin member 66B, and these are bonded and fixed. Thereby, the insulating resin member 66A and the insulating resin member 66B are integrated to form the surrounding member 66, and the breaking member 63X is surrounded by the surrounding member 66.

  Note that through holes are formed in the two plate-like insulating resin members 66A and 66B at positions overlapping the through holes 63G and 63H of the breaking member 63X, respectively. As described above, these through holes constitute the through holes 66G and 66H when the breaking member 63X is surrounded by the insulating resin members 66A and 66B (enclosure member 66). For this reason, when the breaking member 63X is surrounded by the surrounding member 66, the through hole 63H of the breaking member 63X and the through hole 66H of the surrounding member 66 overlap, and further, the through hole 63G of the breaking member 63X and the through hole of the surrounding member 66 Overlap with 66G. And the welding part 63F and the notch part 63E of the fracture | rupture member 63X are exposed in the through-hole 66G of the surrounding member 66 (refer FIG.6, FIG.10, FIG.13).

  Next, it progresses to a welding process and the fracture | rupture member 63X of the positive electrode current collection terminal member 63 is welded to the diaphragm 64 by energy beam welding. In the present embodiment, the fiber laser beam LB is used as the energy beam. Therefore, fiber laser beam welding is performed as energy beam welding. Below, the welding process of this embodiment is demonstrated in detail.

  FIG. 11 is a diagram for explaining the outline of the welding process of the present embodiment. As shown in FIG. 11, the breaking member 63 </ b> X surrounded by the surrounding member 66 is disposed below the laser head 2 of the laser welding machine 7. The breaking member 63X surrounded by the surrounding member 66 is disposed so that the welded portion 63F of the breaking member 63X is exposed to the laser head 2 side from the through hole 66G of the surrounding member 66.

  Further, the diaphragm 64 is disposed under the breaking member 63X surrounded by the surrounding member 66, and the protruding portion 64A of the diaphragm 64 is in contact with the entire welded portion 63F of the breaking member 63X. In this state, the fiber laser beam LB oscillated by a laser oscillator (not shown) is irradiated to the welded portion 63F of the fracture member 63X through the laser head 2.

  In the laser head 2, an incident side lens 3, a reflection plate 4, a diffractive optical element lens 5 (DOE lens), and an emission side lens 6 are arranged in this order from the laser oscillator side (not shown) (see FIG. 11). ). Accordingly, the fiber laser beam LB oscillated by a laser oscillator (not shown) proceeds in the order of the incident side lens 3 → the reflection plate 4 → the diffractive optical element lens 5 → the emission side lens 6, and the welded portion of the fracture member 63X. Irradiated to 63F (see FIGS. 11 and 13).

  By the way, the diffractive optical element lens 5 changes the profile of the fiber laser beam LB into a ring shape. Accordingly, the profile of the fiber laser beam LB before entering the diffractive optical element lens 5 is a solid circle, but the profile of the fiber laser beam LB passes through the diffractive optical element lens 5 to form a ring (annular). )become. After that, even if the fiber laser beam LB passes through the emission side lens 6, the profile remains in a ring shape (annular shape) (see FIG. 12).

  FIG. 12 is a view showing the profile of the fiber laser beam LB that has passed through the diffractive optical element lens 5, and corresponds to the CC cross-sectional view and DD cross-sectional view of FIG. The profile of the fiber laser beam LB is a cross-sectional shape of the fiber laser beam LB, that is, a shape when the advancing fiber laser beam LB is viewed from the front.

  Therefore, in the present embodiment, the fiber laser beam LB can be irradiated to the welded portion 63F of the fracture member 63X through the diffractive optical element lens 5 in a state where the profile of the fiber laser beam LB is ring-shaped (annular). . More specifically, the profile of the fiber laser beam LB irradiated to the welded portion 63F of the breaking member 63X is the entire shape (ring shape) of the welded portion 63F of the breaking member 63X. Irradiation can be performed (see FIGS. 13 and 14). As described above, in the present embodiment, the profile of the fiber laser beam LB can be made into the entire shape of the welded portion 63F through the diffractive optical element lens 5. 14 corresponds to the plan view of FIG.

  By the way, conventionally, when the diaphragm and the rupture member are all-round welded in a ring shape, the rupture member is gradually heated while irradiating a laser beam or the like from the welding start point to the welding end point. Distortion may occur. Due to this thermal strain, a gap is created between the diaphragm and the welded portion of the fracture member. In this state, when the laser beam is irradiated to the welded portion of the fracture member, the fractured member (the location irradiated with the laser beam) is perforated. May occur, resulting in poor welding. This is because the heat capacity is greatly reduced at the relevant portion by separating the welded portion of the breaking member from the diaphragm.

  On the other hand, in the present embodiment, as described above, the profile of the fiber laser beam LB is irradiated on the welded portion 63F of the fracture member 63X in a state where the entire shape (ring shape) of the welded portion 63F of the fracture member 63X is formed. (See FIGS. 13 and 14). Therefore, in the present embodiment, the entire welded portion 63F of the fracture member 63X can be welded to the diaphragm 64 (projecting portion 64A) at the same time.

  In this way, the entire welded portion 63F is simultaneously welded to the diaphragm 64 (projecting portion 64A) at the same time, thereby suppressing the occurrence of thermal distortion in the fracture member 63X, and the diaphragm 64 (projecting portion 64A) and the fracture. It is possible to suppress the occurrence of poor welding (perforation) with the member 63X.

  In the present embodiment, the irradiation time of the fiber laser beam LB with respect to the welded portion 63F of the breaking member 63X is set to 0.02 seconds. The protrusion 64A of the diaphragm 64 is made of aluminum, and the plate thickness is 0.3 mm. The breaking member 63X is made of aluminum, and the plate thickness is 0.2 mm. Further, the inner diameter of the welded portion 63F of the breaking member 63X is 2 mm. Therefore, the inner diameter of the fiber laser beam LB applied to the welded portion 63F of the breaking member 63X is also 2 mm.

  Further, as shown in FIG. 15, the relay member 65, the positive external terminal member 68, and the gasket 69 are caulked and fixed to the sealing lid 82. Specifically, an aluminum rivet 67B whose one end is not expanded in the radial direction is inserted through these through holes in the order of the relay member 65, the sealing lid 82, the gasket 69, and the positive electrode external terminal member 68. Let Next, using a known method, the distal end of the rivet 67B is expanded in the radial direction, and the relay member 65, the positive external terminal member 68, and the gasket 69 are crimped onto the sealing lid 82. Thereafter, the peripheral edge portion 65E of the relay member 65 and the peripheral edge portion 64E of the diaphragm 64 are overlapped and welded. Thereby, the positive electrode terminal structure 60 is completed.

  Further, the negative electrode internal terminal member 71, the negative electrode external terminal member 78, and the gasket 79 are crimped onto the sealing lid 82. Thereby, the negative electrode terminal structure 70 is formed (refer FIG. 2).

  Next, the current collecting connection member 63 </ b> Y of the positive electrode current collecting terminal member 63 is welded to the positive electrode active material layer uncoated portion 20 c of the positive electrode plate 20 of the electrode body 10. Thereby, the positive electrode plate 20 and the positive electrode external terminal member 68 of the electrode body 10 are electrically connected through the positive electrode internal terminal structure 61 (the positive electrode current collecting terminal member 63, the diaphragm 64, the relay member 65, and the caulking member 67). (See FIGS. 1 and 2).

Further, the negative electrode internal terminal member 71 is welded to the negative electrode plate 30 (negative electrode active material layer uncoated portion 30 c) of the electrode body 10. Thereby, the negative electrode plate 30 of the electrode body 10 and the negative electrode external terminal member 78 are electrically connected through the negative electrode internal terminal member 71 (see FIGS. 1 and 2).
At this time, the electrode body 10 is integrated with the positive electrode terminal structure 60, the negative electrode terminal structure 70, and the sealing lid 82.

  Next, the electrode body 10 is accommodated in the battery case 80. Specifically, the electrode body 10 integrated with the sealing lid 82, the positive terminal structure 60, and the negative terminal structure 70 is inserted into the case body member 81. Then, with the sealing lid 82 closing the opening of the case body member 81, the case body member 81 and the sealing lid 82 are welded all around by laser welding. Thereby, the battery case 80 which accommodated the electrode body 10 inside is completed.

  Subsequently, the electrolytic solution 50 is injected into the battery case 80 through a liquid injection hole (not shown) of the battery case 80 (sealing lid 82), and the electrode body 10 in the battery case 80 is impregnated. Thereafter, the liquid injection hole (not shown) is sealed to complete the sealed battery 1 according to the present embodiment (see FIGS. 1 and 2).

(Welding test)
Next, in order to confirm the welding reliability of the welding process of this embodiment, a welding test was performed. Specifically, 50 sets of welding samples (the fracture member 63X of the positive current collecting terminal member 63 and the diaphragm 64) were prepared, and the fracture member 63X and the diaphragm 64 (protrusion 64A) were welded by the above-described welding process. Then, the presence or absence of poor welding (perforation) between the diaphragm 64 (projecting portion 64A) and the fracture member 63X was investigated.

Further, as a comparative example 1, unlike the welding process of the present embodiment, the diaphragm 64 and the fracture member 63X were welded in a ring shape by pulse irradiation of a YAG laser. In Comparative Example 1 as well, 50 sets of welding samples were welded, and the presence or absence of poor welding (perforated) between the diaphragm 64 (projecting portion 64A) and the fracture member 63X was investigated.
In the comparative example 1, the inner diameter of the all-around welding is 2 mm as in the embodiment. Moreover, in the comparative form 1, the welding time (time from the start of irradiation to the end) is set to 0.5 seconds.

Moreover, as a comparative form 2, unlike the welding process of this embodiment, the diaphragm 64 and the fracture | rupture member 63X were all-round welded in the ring shape by CW irradiation (continuous irradiation) of the fiber laser. Also in this comparative form 2, 50 sets of welding samples were welded, and the presence or absence of poor welding (perforated) between the diaphragm 64 (projecting part 64A) and the fracture member 63X was investigated.
In Comparative Example 2, the inner diameter of the all-around welding is 2 mm as in the embodiment. Moreover, in the comparative form 2, the welding time (time from the start of irradiation to the end) is set to 0.05 seconds.

  Here, Table 1 shows the test results of the embodiment and Comparative Examples 1 and 2.

As shown in Table 1, in the welding method of the embodiment, poor welding (perforation) between the diaphragm 64 (projecting portion 64A) and the fracture member 63X did not occur.
On the other hand, in the welding method of comparative form 1, five out of fifty defects (perforation of fracture member 63X) occurred. Further, in Comparative Example 2, 2 out of 50 weld defects (perforation of breakage member 63X) occurred.

  In the welding methods of Comparative Examples 1 and 2, it is considered that poor welding occurred for the following reason. Specifically, while the laser beam is irradiated from the welding start point to the welding end point, the breaking member 63X is gradually heated, and distortion occurs in the breaking member 63X. This thermal distortion is caused by a deviation (time lag) in the timing of irradiation with the laser beam at each point from the welding start point to the welding end point of the welded portion of the fracture member 63X.

  Due to this thermal strain, a gap is generated between the diaphragm 64 and a part of the welded portion 63F of the breakable member 63X. In this state, the welded portion 63F of the breakable member 63X is irradiated with a laser beam, whereby the breakable member 63X. It is thought that a hole was generated in the (location irradiated with the laser beam), resulting in poor welding. This is because a part of the welded portion 63F of the breaking member 63X is separated from the diaphragm 64, so that the heat capacity is greatly reduced at the location.

  On the other hand, in the welding method of the embodiment, the profile of the fiber laser beam LB is irradiated on the welded portion 63F of the breaking member 63X in a state where the entire shape (ring shape) of the welded portion 63F of the breaking member 63X is formed. The entire welded portion 63F of the fracture member 63X is welded to the diaphragm 64 (projecting portion 64A) at the same time (see FIGS. 13 and 14). In this way, the entire welded portion 63F is welded simultaneously (without time lag) to the diaphragm 64 (projecting portion 64A), thereby suppressing the occurrence of thermal distortion in the fracture member 63X, and the diaphragm 64 (projecting portion). 64A) and the fracture member 63X are considered to be able to suppress the occurrence of poor welding (perforation).

(Deformation)
Next, modifications of the present invention will be described. Compared with the embodiment, the present modified embodiment is different in the shape of the welded portion 63F of the fracture member 63X and the profile of the fiber laser beam LB in the welding process, and is otherwise the same.

  Specifically, in the embodiment, the entire shape of the welded portion 63F of the breaking member 63X is a ring shape (annular shape) (see FIG. 7). On the other hand, in this modification, the entire shape of the welded portion 163F of the breaking member 163X is a shape in which a part of the ring is missing (specifically, four arcs are arranged on the circumference at equal intervals with a gap between them. (See FIG. 17). FIG. 17 is a diagram corresponding to FIG. 7 of the embodiment.

  Furthermore, in the welding process of the present modified embodiment, the profile of the fiber laser beam LB is made to have a shape in which a part of the ring is missing (in detail, the four arcs are gaps) as in the overall shape of the welded portion 163F of the fracture member 163X. In a state in which the laser beam LB is formed at equal intervals on the circumference), the fiber laser beam LB is irradiated to the welded portion 163F of the fracture member 163X (see FIG. 16).

  FIG. 16 is a view showing the profile of the fiber laser beam LB that has passed through the diffractive optical element lens 105, and corresponds to the CC cross-sectional view and DD cross-sectional view of FIG. In this modification, a welding process is performed using a laser welding machine 107 having a laser head 102 incorporating a diffractive optical element lens 105 (see FIG. 11). The laser head 102 of this modification is different from the laser head 2 of the embodiment only in that the diffractive optical element lens 5 is changed to a diffractive optical element lens 105. In FIG. 11, portions different from the embodiment in the modified embodiment are described with reference numerals in parentheses.

  The diffractive optical element lens 105 changes the profile of the fiber laser beam LB (from a solid circle) to “a shape in which four arcs are arranged on the circumference at equal intervals with a gap”. Therefore, in this modification, the profile of the fiber laser beam LB is set to “a shape in which four arcs are arranged on the circumference at equal intervals with a gap”, which is the same as the overall shape of the welded portion 163F of the breaking member 163X. In this state, the fiber laser beam LB can be irradiated to the welded portion 163F of the breaking member 163X.

  Also in this modified embodiment, the profile of the fiber laser beam LB is applied to the welded portion 163F of the fracture member 163X in a state where the entire shape of the welded portion 163F of the fracture member 163X is applied to the diaphragm 64 (projecting portion 64A). The entire welded portion 163F of the breaking member 163X can be welded together at the same time. In this way, the entire welded portion 163F is simultaneously welded to the diaphragm 64 (projecting portion 64A) at the same time, thereby suppressing the occurrence of thermal distortion in the fracture member 163X, and the diaphragm 64 (projecting portion 64A) and the fracture. It is possible to suppress the occurrence of poor welding (perforation) with the member 163X.

  In the above, the present invention has been described with reference to the embodiments and modifications. However, the present invention is not limited to the above-described embodiments and the like, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. Yes.

1 Sealed battery 2,102 Laser head 5,105 Diffractive optical element lens (DOE lens)
7, 107 Laser welding machine 10 Electrode body 20 Positive electrode plate 28 Positive electrode current collector foil 30 Negative electrode plate 50 Electrolytic solution 60 Positive electrode terminal structure 61 Positive electrode internal terminal structure 62 Current interruption mechanism 63, 163 Positive electrode current collector terminal member 63F Welding part 63X , 163X Breaking member 63Y Current collecting connection member 64 Diaphragm 66 Enclosing member 68 Positive electrode external terminal member (external terminal)
70 Negative electrode terminal structure 71 Negative electrode internal terminal member 78 Negative electrode external terminal member 80 Battery case 81 Case body member 82 Sealing lid LB Fiber laser beam (energy beam)

Claims (3)

An external terminal, an electrode body, a battery case that houses the electrode body, and a current blocking mechanism that blocks current flowing through the electrode body when an internal pressure of the battery case exceeds an operating pressure,
The current interruption mechanism is
A diaphragm that is electrically connected to the external terminal and deforms as the internal pressure of the battery case increases,
Electrically connected to the electrode body and electrically connected by being welded to the diaphragm, deformed together with the diaphragm deformed as the internal pressure of the battery case increases, and the internal pressure of the battery case is activated In a manufacturing method of a sealed battery having a breaking member that cuts off electricity between the diaphragm and the electrode body by itself breaking when the pressure is exceeded,
The breaking member has a welded portion welded to the diaphragm by energy beam welding,
In the welding step of welding the fracture member to the diaphragm by energy beam welding, the energy beam profile is irradiated to the fracture member in a state where the profile of the energy beam is the shape of the entire weld portion, so that the entire weld portion is A method of manufacturing a sealed battery that is welded together at the same time ,
The energy beam is a fiber laser beam . A method for manufacturing a sealed battery. It is a manufacturing method of the sealed battery according to claim 1,
In the welding process, a sealed battery manufacturing method in which a profile of the fiber laser beam is formed in the entire welded portion through a diffractive optical element lens. It is a manufacturing method of the sealed battery according to claim 1 or 2 ,
The overall shape of the weld is a ring,
In the welding step, a sealed battery manufacturing method of irradiating the rupture member with the fiber laser beam in a state where the profile of the fiber laser beam is in the ring shape.

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