JP6107346B2 - Battery manufacturing method and battery - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a battery including an electrode body having a foil multilayer portion in which foil exposed portions of aluminum foil overlap each other in a stacking direction in a positive electrode plate, and a positive electrode terminal member made of aluminum, and a method for manufacturing such a battery. .

  In recent years, a chargeable / dischargeable battery has been used as a driving power source for vehicles such as hybrid vehicles and electric vehicles, and portable electronic devices such as notebook computers and video camcorders. As a technique used for such a battery, for example, Patent Document 1 discloses a joining method in which a laminated aluminum foil is resistance-welded to a base plate made of aluminum. Specifically, this joining method includes an ultrasonic tempering step for forming a temporary attachment portion in which a plurality of laminated aluminum foils are temporarily attached by ultrasonic welding, and the temporary attachment portion and the base plate with two electrodes. And a resistance welding step of energizing these electrodes and resistance welding the temporary attachment portion and the base plate.

JP 2010-184260 A

  By the way, in general, when two metal members are resistance-welded, a nugget (a region formed by melting, mixing and solidifying a part of two metal members) is formed between them. Weld two metal parts. If the size of the nugget formed is small, the welding strength between the two metal members will be low, so it is required to form a large nugget in order to ensure the welding strength. On the other hand, if the nugget becomes too large, a large amount of molten metal is ejected from the nugget to become vacancies, and conversely, the welding strength may be reduced.

  A high resistance oxide film (alumina film) is present on each surface of the temporary attachment part (foil multilayer part) and the base plate (positive electrode terminal member) used in the joining method described in Patent Document 1 described above. . Therefore, in order to weld by applying an electric current to a temporary attachment part and a base board, it is necessary to destroy a part of oxide film of each surface, and it is necessary to apply a high voltage between the electrodes for resistance welding.

  On the other hand, in the joining method of Patent Document 1, since the contact surfaces of the temporary attachment portion and the base plate are both flat, the welding location (the portion where the current flows) is not determined, and one portion where the oxide film is destroyed first. Current concentrates on. Moreover, since a large current due to the high voltage flows through the temporary attachment portion and the base plate, only one nugget tends to increase instantaneously. For this reason, since the thickness of the temporary attachment part or base plate which sandwiches the nugget in the stacking direction becomes thin and easily breaks, a large amount of molten aluminum is easily ejected from the nugget to the external side of the temporary attachment part or base plate. It is difficult to secure welding strength between the base plate and the base plate.

  The present invention relates to a battery manufacturing method that secures a good welding strength between the foil multilayer portion of the electrode body and the positive electrode terminal member by resistance welding, and the foil multilayer portion and the positive electrode terminal member. It aims at providing the battery which ensured favorable welding strength between.

One embodiment of the present invention includes a positive electrode plate including an aluminum foil, an electrode body having a foil multilayer portion in which the exposed foil portions of the aluminum foil overlap each other in the stacking direction, and a positive electrode made of aluminum. Terminal foil, and a method of manufacturing a battery in which the foil layered portion and the positive electrode terminal member are resistance-welded in the stacking direction, and the aluminum foils that overlap each other are superposed on the foil layered portion. A foil welded portion forming step for forming foil welded portions welded to each other in the laminating direction by sonic welding, and a resistance welding step for resistance welding the foil welded portion of the electrode body and the positive electrode terminal member, and The foil welded portion forming step is located on one side in the laminating direction on the surface of the foil welded portion, and at a part of the planned joining surface to be joined with the positive electrode terminal member, A high level part and a plurality of first low level parts arranged in a dotted pattern in the planned joining surface at a lower level than the first high level part, and the above among the surfaces of the foil welded part Positioned on the other side in the stacking direction and on at least a part of the electrode contact surface with which the first resistance welding electrode is contacted, a second high level portion higher on the other side in the stacking direction, and a comparison with the second higher level portion. And forming a plurality of second low-order parts arranged at positions overlapping with each other in the stacking direction in the electrode contact surface, and the resistance welding step includes 1 resistance welding electrode, the foil welded portion, the positive electrode terminal member, and the second resistance welding electrode are stacked in this order, and the second resistance welding electrode is crushed in the laminating direction with the first resistance welding electrode. A plurality of the above-mentioned aluminum foils are bent and laminated in a U-shaped cross section at the second lower portion, respectively. Formed into shaped portion, while preventing the welding between the first resistance welding electrode and the foil welded part, a method for producing a battery for generating a nugget in the first low portion by a current flowed.

In the resistance welding step of the battery manufacturing method described above, the first high level portion of the foil welded portion is brought into contact with the positive electrode terminal member to pass a current, and a nugget is generated at the first low level portion.
The following can be considered as the reason why the nugget is generated in the first low-order part. That is, in the first high-order part of the foil welded part, the aluminum foils are not strongly pressed in the height direction (the lamination direction of the aluminum foil) and do not overlap closely as the first low-order part. For this reason, during resistance welding, the current inside the first high level portion is relatively difficult to flow in the stacking direction, so that the current flowing through the first high level portion is the height direction (stacking direction) inside the first high level portion. Rather than proceeding to (1), it proceeds to the first lower portion through the aluminum foil having a side surface or a slope located between the first higher portion and the first lower portion, and proceeds in the stacking direction at this first lower portion (or This route is considered to be reversed). Therefore, during resistance welding, current flows in a concentrated manner on the side surface or slope around the first low-order part, and this part and the first low-order part melt. Further, in the resistance welding process, since the first high-order part is brought into contact with the positive electrode terminal member and welding is performed, the first high-order part is pressed in the laminating direction, and one aluminum foil constituting the first high-order part is formed. The part is pushed out in the direction of spreading around the first high-order part. The extruded aluminum is also melted on the side surface or the slope between the first high-order part and the first low-order part, so that it is considered that a large nugget is generated.

  On the other hand, in the foil welded part forming step, a foil welded part in which a plurality of first low-order parts are arranged in a dotted pattern within the planned joining surface is formed. For this reason, a nugget can be produced | generated in each position of a 1st low-order part, if the joining plan surface of this foil welding part is contact | abutted to a positive electrode terminal member, and these are resistance-welded. As a result, only one nugget can be prevented from becoming extremely large between the foil welded portion and the positive electrode terminal member, and molten aluminum can be prevented from being ejected from the nugget, and even if it is ejected, the amount can be kept small. Can do.

  Moreover, in this resistance welding process, since the plurality of second high-order parts are crushed in the stacking direction by the first resistance welding electrode, the oxide film covering the aluminum foil of each second high-order part is destroyed, and the electrode contact Aluminum (new surface) is exposed on the surface at a plurality of locations. As a result, the contact resistance between the first resistance welding electrode and the electrode contact surface (second high-order part) is lowered, and since the contact is made at a plurality of locations, the current is dispersed and is difficult to generate heat. Welding between the first resistance welding electrode and the foil welded portion (electrode contact surface) during resistance welding can be prevented.

Furthermore, in the molded foil welded part, the second low-order part is arranged at a position overlapping the first low-order part in the stacking direction. In the resistance welding process, when the second high-order part is crushed in the stacking direction by the first resistance welding electrode, the surrounding part of the second high-order part moves toward the second low-order part. As a result, the plurality of aluminum foils laminated between the second low-level part and the second high-level part are deformed to be bent into a U-shaped cross section (U-shaped part). .
Therefore, the nugget and the U-shaped part are arranged in the stacking direction. In the U-shaped part, since a plurality of aluminum foils are bent and stacked in the stacking direction, a gap is generated between the aluminum foils, and heat is not easily transmitted in the stacking direction. In addition, the electrode contact surface can be separated from the nugget by increasing the dimension in the stacking direction as compared with the case where the same number of aluminum foils are stacked in a flat plate shape. By these, it can suppress that heat transfers from a nugget to an electrode contact surface, and can further suppress welding with the electrode for 1st resistance welding, and an electrode contact surface.

Moreover, since the above-mentioned U-shaped part is located on the electrode contact surface side in the stacking direction when viewed from the nugget, the nugget is difficult to grow in the stacking direction in the U-shaped part. This is because, in the U-shaped part, a gap is generated between the laminated aluminum foils, so that current does not easily flow in the lamination direction. Therefore, the nugget easily grows in the spreading direction, and a nugget having a large area (cross-sectional area) can be interposed in the spreading direction at the interface between the positive electrode terminal member and the foil layered portion (foil welded portion). And the weld strength between the foil layered portion can be further increased.
Thus, it is possible to manufacture a battery while ensuring good welding strength between the foil multi-layer part and the positive electrode terminal member and suppressing adhesion of aluminum from the electrode contact surface to the first resistance welding electrode.

  In addition, as the foil welded part forming step, after forming the foil welded part by welding the aluminum foils of the exposed foil part to each other by ultrasonic welding, the first high-order part and the first low-order part are formed on the surfaces to be joined by pressing. And a step of providing the second high-order part and the second low-order part on the electrode contact surface, respectively. In addition, an uneven shape is formed on the horn or anvil used for ultrasonic welding, and the aluminum foils are ultrasonically welded together. At the same time, the first high-order part and the first low-order part are provided on the planned joining surface, and the electrode contact surface is provided with the first high-order part. The process of providing 2 high level part and 2nd low level part is also mentioned, respectively. In addition, examples of the first low-order part or the second low-order part include a conical recess, a polygonal pyramid-shaped recess such as a pyramid (square pyramid), and a truncated cone-shaped recess such as a quadrangular pyramid. It is done. Moreover, as arrangement | positioning of the some 1st low-order part in a joining plan surface, a grid | lattice form and radial arrangement | positioning are mentioned, for example.

  Furthermore, in the battery manufacturing method described above, the first low-order part and the second low-order part of the foil welded part are each configured to form a bottom surface of a frustum-shaped recess, Of these, the dimension in the stacking direction from the planned joining surface to the first low-order part is defined as a first depth dimension D1, and the dimension in the stacking direction from the electrode contact surface to the second low-order part is defined as a second depth. The battery manufacturing method in which the ratio D2 / D1 of the second depth dimension D2 and the first depth dimension D1 is within the range of 0.3 ≦ D2 / D1 ≦ 0.9 when the thickness dimension D2 is set. And good.

The foil welded portion in which the ratio D2 / D1 between the second depth dimension D2 of the second low-order part and the first depth dimension D1 of the first low-order part is in the range of 0.3 ≦ D2 / D1 ≦ 0.9. It has been found that when resistance welding is carried out using aluminum, adhesion of aluminum from the electrode contact surface to the first resistance welding electrode can be reliably suppressed.
On the other hand, if the ratio D2 / D1 is smaller than 0.3, the U-shaped portion is apt to be crushed small, so that current easily flows there, and the growth of the nugget on the electrode contact surface side in the stacking direction cannot be suppressed. The nugget approaches the electrode contact surface. For this reason, during resistance welding, the heat of the nugget is easily transmitted to the electrode contact surface, and the first resistance welding electrode and the electrode contact surface are easily welded.
On the other hand, when resistance welding is performed using a foil welded portion having a ratio D2 / D1 greater than 0.9, the first resistance welding electrode and electrode are compared with a case where a foil welded portion having a ratio D2 / D1 of 0.9 or less is used. The contact area with the contact surface is reduced. This is because the first low-order part and the second low-order part both form the bottom of the frustum-shaped recess, and therefore when the first depth dimension D1 is constant and the ratio D2 / D1 increases, the second depth The dimension D2 is increased, and the space surrounded by the frustum-shaped recess including the second low-order part is also increased. This is because the area of the second high-order part forming this electrode contact surface is reduced. For this reason, since the electric current which flows at the time of resistance welding is hard to disperse | distribute on an electrode contact surface and it is easy to generate | occur | produce heat, it is thought that this electrode contact surface and the electrode for 1st resistance welding are easy to weld.

  On the other hand, in the battery manufacturing method described above, the ratio D2 / D1 is within the range of 0.3 ≦ D2 / D1 ≦ 0.9 at the foil welded portion. A battery can be manufactured while reliably preventing aluminum from adhering to the first resistance welding electrode.

Alternatively, another aspect of the present invention includes a positive electrode plate including an aluminum foil, and an electrode body having a foil multilayer portion in which the exposed foil portions of the aluminum foil overlap each other in the stacking direction in the positive electrode plate, includes a positive terminal member made of aluminum, and the foil multilayer portion and the said positive terminal member, between the heavy Naru the foil layer portion and the positive terminal member in the lamination direction, the spreading direction of the aluminum foil The plurality of aluminum foils are cross-sectioned in each of the portions where the nuggets are present on the positive electrode terminal member side in the stacking direction in the foil multi-layered portion, which are combined through a plurality of nuggets distributed in a scattered manner. It is a battery formed into a U-shaped portion bent and stacked in a U-shape.

In the battery described above, the foil multi-layer part and the positive electrode terminal member are bonded via a plurality of nuggets distributed in the form of scattered dots in the spreading direction of the aluminum foil. A battery joined with good strength can be obtained.
In addition, any portion of the foil multilayer portion where nuggets exist in the stacking direction is a plurality of U-shaped portions. In this U-shaped part, there is a gap between the laminated aluminum foils, and it is difficult for current to flow in the stacking direction. Therefore, when resistance welding is performed, the nugget is grown in the stacking direction in the U-shaped part. It is possible to suppress the growth of the aluminum foil in the spreading direction. For this reason, a nugget having a large area (cross-sectional area) can be interposed in the spreading direction at the interface between the positive electrode terminal member and the foil multilayer portion, and the positive electrode terminal member and the foil multilayer portion are joined with higher welding strength. It can be.

It is a perspective view of the battery concerning embodiment (Examples 1-3 ). It is a top view of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing (partial enlarged view of the E section of FIG. 2) of the battery concerning embodiment (Examples 1-3 ). It is sectional drawing (BB cross section of FIG. 2) of the battery concerning embodiment (Examples 1-3 ). It is a partial expanded sectional view (C section of Drawing 4 ) of a battery concerning an embodiment (Examples 1-3 ). It is a perspective view of the positive electrode plate of embodiment (Examples 1-3 ). It is explanatory drawing of a foil welding part shaping | molding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing of a foil welding part shaping | molding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing of a foil welding part shaping | molding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ). It is a perspective view of the foil welding part of the battery concerning embodiment (Examples 1-3 ). It is a perspective view of the foil welding part of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing of a foil welding part shaping | molding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing of a resistance welding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing of a resistance welding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing of a resistance welding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ). It is explanatory drawing of a resistance welding process among the manufacturing methods of the battery concerning embodiment (Examples 1-3 ).

(Embodiment)
Next, Example 1 of the embodiments of the present invention will be described with reference to the drawings. First, the battery 1 according to Example 1 will be described. The battery 1 includes a flat wound electrode body 10, a positive electrode terminal structure 60 that is resistance-welded to a positive electrode plate 20 (described later) that forms the electrode body 10, and a battery case 80 that houses the electrode body 10. This is a sealed lithium ion secondary battery (see FIGS. 1 and 2). In addition to these, the battery 1 includes a negative electrode terminal structure 70 joined (resistance welded) to a negative electrode plate 30 (described later) forming the electrode body 10. The positive electrode terminal structure 60 of the battery 1 has an energization interruption mechanism 62 (described later) that interrupts energization of the electrode body 10 due to an increase in internal pressure of the battery case 80 (see FIGS. 1 and 2).

A battery case 80 constituting the battery 1 has a bottomed rectangular box-shaped battery case main body 81 and a rectangular plate-shaped sealing lid 82 both made of aluminum. Among these, the sealing lid 82 closes the opening of the battery case body 81 and is welded to the battery case body 81.
The negative electrode terminal structure 70 is made of copper, and is mainly composed of a negative electrode internal terminal member 71 located inside the battery case 80, a negative electrode external terminal member 78 also made of copper and located outside the battery case 80, and insulation. It consists of a gasket 79 of a conductive resin (see FIGS. 1 and 2). Among these, the gasket 79 is interposed between the negative electrode external terminal member 78 and the negative electrode internal terminal member 71 and the battery case 80 to insulate them. In addition, the negative electrode internal terminal member 71 is joined to a negative electrode lead portion 38 f (described later) of the negative electrode plate 30 in the battery case 80, while penetrating the sealing lid 82 of the battery case 80 to be connected to the negative electrode external terminal member 78. And continuity.

  On the other hand, the positive electrode terminal structure 60 is mainly composed of a positive electrode internal terminal structure 61 positioned inside the battery case 80, a positive electrode external terminal member 68 made of aluminum and positioned outside the battery case 80, and an insulating resin gasket 69. (See FIGS. 1 and 2). Among these, the gasket 69 is interposed between the positive electrode external terminal member 68 and the positive electrode internal terminal structure 61 and the battery case 80 and insulates them, like the negative electrode terminal structure 70.

Further, the positive electrode internal terminal structure 61 is a known member positioned between a bonding member 63 bonded to a positive electrode foil welded portion 12 (described later) of the electrode body 10 by resistance welding and the bonding member 63 and the positive electrode external terminal member 68. And an energization cutoff mechanism 62. The energization cutoff mechanism 62 is configured to cut off the current flowing between the positive electrode internal terminal structure 61 and the positive electrode external terminal member 68 when the internal pressure of the battery case 80 rises to be equal to or higher than the operating pressure. .
Further, as shown in FIG. 4, the joining member 63 is a flat plate-like main body portion 63 </ b> X that is electrically connected to the energization cutoff mechanism 62, and extends from the main body portion 63 </ b> X to the electrode body 10 side. It consists of two rectangular strip-shaped joints 63Y, 63Y. The two joint portions 63Y and 63Y are respectively located on both outer sides in the minor axis direction (left and right direction in FIG. 4) of the electrode body 10 having a flat shape, and are joined to the positive electrode foil weld portion 12 (described later). .

On the other hand, the electrode body 10 is formed by winding a belt-like positive electrode plate 20 and a negative electrode plate 30 into a flat shape via a belt-like separator (not shown) made of polyethylene (see FIG. 1). The electrode body 10 is impregnated with an electrolyte solution (not shown) obtained by adding LiPF ₆ to an organic solvent.
In addition, in this electrolytic solution, when the potential of the positive electrode plate 20 becomes equal to or higher than its own reaction potential, a gas generating agent (in this embodiment, biphenyl) that generates a gas through an oxidative decomposition reaction and a polymerization reaction occurs. Including. For this reason, in the battery 1 of the first embodiment, when the battery is overcharged and the potential of the positive electrode plate 20 becomes equal to or higher than the reaction potential of the gas generating agent, gas is generated in the battery case 80, and the battery The internal pressure of the case 80 increases. And if an internal pressure exceeds the operating pressure of the electricity supply interruption | blocking mechanism 62 mentioned above, electricity supply to the electrode body 10 will be interrupted | blocked and subsequent overcharge to the battery 1 will be suppressed.

  The negative electrode plate 30 constituting the electrode body 10 carries a negative electrode active material layer (not shown) on both sides of the strip-like negative electrode foil (not shown), leaving a negative electrode lead portion 38f along one side. Further, as shown in the perspective view of FIG. 6, the positive electrode plate 20 includes a positive electrode foil 28 made of aluminum in a strip shape extending in the longitudinal direction DA and a short direction DB DB of the positive electrode foil 28 (both main surfaces of the positive electrode foil 28). It has two strip-shaped positive electrode active material layers 21, 21 that are formed to be biased to the side (upper left side in FIG. 6) and extend in the longitudinal direction DA of the positive electrode foil 28. Thus, the positive electrode plate 20 has a positive electrode lead portion 28f where the positive electrode foil 28 is exposed from the positive electrode active material layer 21 on the other side (lower right side in FIG. 6) of the positive electrode foil 28 in the short direction DB.

  As shown in FIG. 2, the electrode body 10 has the positive electrode lead portions 28 f and 28 f of the positive electrode plate 20 on one side (right side in FIG. 2) on the axial direction DX side. And a positive foil layer 11 having a substantially oval cross section. Furthermore, the positive electrode foil multilayer portion 11 includes a positive electrode foil welded portion 12 in which the positive foils 28 of the positive electrode lead portion 28f are welded to each other in the laminating direction DT by ultrasonic welding in a parallel portion of an ellipse (FIGS. 2 to 4). reference).

  In the battery 1 according to Example 1, as shown in FIGS. 3 and 4, the positive electrode foil welded portion 12 of the positive foil multilayer portion 11 and the above-described joining member 63 (joint portion 63Y) of the positive electrode terminal structure 60 are resistant. Welded. And as shown in FIG. 3 (partial enlarged view of the E part of FIG. 2) and sectional drawing of FIG. 5 (partial enlarged sectional view of the C part of FIG. 4), the positive electrode foil welding part 12 and the joining member 63 ( The joint 63Y) is joined through a plurality of nuggets N, N formed by melting them during resistance welding. As shown in FIG. 3, the plurality of nuggets N and N are distributed in the form of dots (lattice) in the spreading direction of the positive foil 28 (in the direction parallel to the paper surface in FIG. 3).

  In addition, as shown in FIG. 5, in the battery 1, in the positive electrode foil welded portion 12 of the positive foil laminated portion 11, the joining member 63 side of the positive electrode terminal structure 60 in the stacking direction DT (left side in FIG. 5). Each of the portions where the nugget N exists is a U-shaped portion LU. That is, in the positive electrode foil welded portion 12, the nugget N and the U-shaped portion LU are arranged side by side in the stacking direction DT. The U-shaped portion LU is a portion where a plurality of positive foils 28 and 28 constituting the positive foil multilayer portion 11 are bent and laminated in a U-shaped cross section. The U-shaped portion LU is a portion formed by deforming a plurality of surrounding positive electrode foils 28 and 28 in a second low-order portion 14E (described later) of the positive electrode foil welded portion 12 in a resistance welding process described later. is there.

  In the battery 1 according to this embodiment, the positive electrode foil welded portion 12 of the positive electrode foil multilayer portion 11 and the positive electrode terminal structure 60 are arranged via a plurality of nuggets N, N distributed in the form of dots in the spreading direction of the positive electrode foil 28. Thus, the battery 1 in which the positive foil laminated portion 11 (positive foil welded portion 12) and the positive terminal structure 60 are joined with good strength can be obtained.

  In addition, in the battery 1, the portion where the nugget N is present in the stacking direction DT in the positive foil layered portion 11 (positive foil welded portion 12) is a plurality of U-shaped portions LU, LU. In this U-shaped portion LU, a gap is formed between the stacked positive electrode foils 28 and 28, and it is difficult for current to flow in the stacking direction DT. The growth in the spreading direction of the positive electrode foil 28 can be promoted by suppressing the growth in the stacking direction DT in the LU. For this reason, the nugget N having a large area (cross-sectional area) can be interposed in the spreading direction at the interface between the positive electrode terminal structure 60 and the positive electrode foil multilayer portion 11 (positive electrode foil welded portion 12). And the positive electrode foil multilayer portion 11 (positive electrode foil welded portion 12) can be made into a battery 1 joined with higher welding strength.

  Next, a method for manufacturing the battery 1 according to Example 1 will be described with reference to FIG. First, a belt-like separator is interposed between the belt-like positive electrode plate 20 and the negative electrode plate 30 each produced by a known method, and these are wound around the winding axis AX. At this time, the positive electrode lead portion 28f of the positive electrode plate 20 is on one side in the axial direction DX of the winding axis AX (left side in FIG. 7), and the negative electrode lead portion 38f of the negative electrode plate 30 is on the other side in the axial direction DX (FIG. 7). Each was placed on the middle and right side) and wound. After winding, the electrode body 10 was deformed into a flat shape to form a flat wound electrode body 10 (see FIG. 7). This electrode body 10 has a positive electrode foil multilayer portion 11 in which the positive electrode lead portions 28f of the positive electrode foil 28 overlap with each other on the other side in the axial direction DX (left side in FIG. 7).

Next, the foil welded part forming step in the method for manufacturing the battery 1 according to the first embodiment will be described. This foil welded portion forming step is a step of forming the positive electrode foil welded portion 12 in which the positive foils 28 and 28 that are overlapped with each other are welded to each other in the stacking direction DT by ultrasonic welding.
In the foil welded part forming step, both the first block body 110 and the second block body 120 made of steel are used (see FIG. 7). Among these, the 1st block body 110 is a substantially rectangular plate shape, and the front-end | tip part 112 is notched in the thickness direction, and has a triangular prism shape (blade shape). Moreover, the 2nd block body 120 has the front end surface 121 of the state by which the one part of the thickness direction was notched by the substantially rectangular plate shape.

  In the foil welded part forming step, first, the first block body 110 is inserted into the center of the positive electrode foil multilayer part 11 of the electrode body 10. Specifically, as shown in FIG. 7, the first block body 110 having the triangular columnar tip 112 arranged on the electrode body 10 side is moved from the left side to the right side in FIG. 7 along the winding axis AX. Let And the positive electrode foil multilayer part 11 is divided into two by the 1st block body 110 (refer FIG. 8). At the same time, the second block body 120 is pressed against the parallel part of the ellipse in the positive electrode foil multilayer portion 11 from the outside. Specifically, as shown in FIG. 7, the second block body 120 is placed so that the above-described distal end surface 121 faces the parallel portion extending in the major axis direction DL (vertical direction in FIG. 7) of the positive electrode foil multilayer portion 11. It is moved in the minor axis direction DS (in FIG. 7, from the lower right side to the upper left side). As a result, the positive electrode lead portion 28f (left side in FIG. 8) of the positive electrode foil 28 is connected to the front end surface 121 of the second block body 120 and the first portion in the oblong parallel portion of the positive electrode foil multilayer portion 11. The positive electrode foil proximity portion 12B is formed between the side surfaces 111 of the block body 110 and is brought close to the stacking direction DT (see FIG. 8).

Subsequently, as shown in FIG. 9, the positive electrode foil 28 (positive electrode lead portion 28f) overlapping in the stacking direction DT at the positive electrode foil proximity portion 12B is ultrasonically welded. Specifically, an ultrasonic welding apparatus 130 that vibrates the horn processed surface 132 of the horn 131 in parallel with the anvil processed surface 137 of the anvil 136 facing the horn processed surface 130 is used.
Note that a plurality of first convex portions 133 that are convex in a quadrangular pyramid shape are arranged in a lattice shape (specifically, 2 rows × 6 rows) on the horn processed surface 132 that is the tip surface of the horn 131. The pitch between the 1st convex parts 133 and 133 in this horn process surface 132 is 0.90 mm. On the other hand, on the anvil machining surface 137 of the anvil 136, a plurality of second convex portions 138 convex in a quadrangular pyramid shape are arranged in a lattice shape (specifically, 2 rows × 6 rows). The pitch between the second convex portions 138 and 138 on the anvil processed surface 137 is 0.90 mm which is the same as the pitch between the first convex portions 133 and 133 on the horn processed surface 132.
Moreover, the 1st convex part 133,133 of the horn process surface 132 and the 2nd convex part 138,138 of the anvil process surface 137 mutually oppose on both sides of the positive electrode foil proximity | contact part 12B (refer FIG. 9).

  With the horn 131 and the anvil 136 of the ultrasonic welding apparatus 130, the positive foil proximity portion 12B is pressed in the stacking direction DT and ultrasonic vibration is applied from the horn 131 so that the positive foil 28 of the positive foil proximity portion 12B is attached. Ultrasonic welding. As a result, the foil-welded portion 12 </ b> C in which the cathode foils 28, 28 are welded and integrated with each other in the stacking direction DT on the cathode foil multilayer portion 11 is formed.

As shown in FIG. 10, the foil welded portion 12C has a short-diameter outer side DS1 on the first foil-welded surface 13 facing the outer side DS1 (upper side in FIG. 10) of its own surface. The first high-order part 13D, which is higher than the first high-order part 13D, and the first low-order part 13E, which is lower than the first high-order part 13D, are formed. In the present embodiment, the bottom of the quadrangular pyramid-shaped recess formed by the first convex portion 133 of the horn 131 described above is the first low-order portion 13E, and the portion between the recesses is the first high-order portion 13D. (See FIG. 10).
As shown in FIG. 10, the first high level portion 13 </ b> D is located on the same plane as the first foil welding surface 13. In addition, the first low-order part 13E has a lattice shape (specifically, two rows in the axial direction DX and a long-diameter direction DL) at a pitch P1 of 0.90 mm in the first high-order part 13D (first foil welding surface 13). 6 rows) (see FIG. 10). Moreover, the 1st depth dimension D1 of the lamination direction DT from the 1st foil welding surface 13 to the 1st low-order part 13E is 0.40 mm (refer FIG. 12).

On the other hand, as shown in FIG. 11, among the surfaces of the foil welded portion 12C, the second foil weld surface 14 facing the inner side DS2 (upper side in FIG. 11) faces the second inner side DS2 higher than the inner surface DS2. The second high-order part 14D and the second low-order part 14E which is lower than the second high-order part 14D are formed. In the present embodiment, the bottom of the square frustum-shaped depression formed by the second convex part 138 of the anvil 136 described above is the second low-order part 14E, and the part between the depressions is the second high-order part 14D. (See FIG. 11).
As shown in FIG. 11, the second high-order part 14 </ b> D is located on the same plane as the second foil welding surface 14. In addition, the second low-order part 14E has a lattice shape (specifically in the axial direction DX) at the same pitch P1 of 0.90 mm as the first low-order part 13E in the second high-order part 14D (second foil welding surface 14). 2 rows and 6 rows in the major axis direction DL) (see FIG. 11). Further, the second depth dimension D2 in the stacking direction DT from the second foil welding surface 14 to the second low-order part 14E is 0.12 mm (see FIG. 12).
In the foil welded portion 12C, the second low level portion 14E of the second foil weld surface 14 overlaps the first low level portion 13E of the first foil weld surface 13 in the stacking direction DT, that is, the second low level. The part 14E and the first low-order part 13E are arranged in the same phase (see FIGS. 12 and 14).

  Next, a foil welded portion 12C is similarly produced on the opposite side of the elliptical parallel portions of the positive electrode foil multilayer portion 11. As a result, the electrode body 10 in which the foil welded portions 12C and 12C are formed on each of the parallel portions of the ellipse of the positive foil layered portion 11 divided into two is completed (see FIG. 12).

  Next, the resistance welding process in the manufacturing method of the battery 1 according to the first embodiment will be described. In this resistance welding process, a known resistance welding apparatus 140 having a first electrode 141 and a second electrode 146 made of copper is used. In the resistance welding apparatus 140, the first electrode surface 142 of the first electrode 141 and the second electrode surface 147 forming the tip surface of the second electrode 146 are coaxially opposed to each other (see FIG. 13). Each of the first electrode surface 142 and the second electrode surface 147 has a circular outer periphery and slightly bulges into a spherical shape (see FIG. 15).

  In the resistance welding step, first, the joint portion 63Y of the joint member 63 of the positive electrode terminal structure 60 is brought into contact with the foil welded portion 12C of the positive electrode foil multilayer portion 11 of the electrode body 10 (see FIGS. 13 and 14). Specifically, the positive electrode terminal structure 60 having the energization interruption mechanism 62 is assembled to the sealing lid 82 in advance by a known method. Then, one of the two joint portions 63Y and 63Y of the positive electrode terminal structure 60 is brought into contact with one of the first foil weld surfaces 13 of the two foil weld portions 12C and 12C on the electrode body 10 (see FIG. 13). ). Thereby, as shown in FIG. 14, among the foil welded parts 12C, the first high-order part 13D of the first foil welded surface 13 is brought into contact with the joint part 63Y. Note that a portion of the joint portion 63Y that is in contact with the first high-order portion 13D is referred to as a contact portion 63YT (see FIG. 14).

Next, using the above-described resistance welding apparatus 140, the joint portion 63Y of the positive electrode terminal structure 60 and the foil welded portion 12C in contact therewith are resistance-welded. Specifically, in the resistance welding apparatus 140, the first electrode 141 is on the second foil welding surface 14 side in the foil welded portion 12C, and the second electrode 146 is on the joint 63Y side of the positive electrode terminal structure 60, respectively. Arrange (see FIG. 15). Thus, the first electrode 141, the foil welded portion 12C, the joint portion 63Y of the positive terminal structure 60, and the second electrode 146 are overlapped in this order.
Then, the first electrode 141 and the second electrode 146 sandwich the foil welded portion 12C and the joining portion 63Y in the stacking direction DT of the positive foil 28. FIG. 16 is a cross-sectional view showing a state in which the first electrode 141 and the second electrode 146 sandwich the foil welded portion 12C and the joint portion 63Y. Due to the clamping pressure between the first electrode 141 and the second electrode 146, the first high-order part 13D is in pressure contact with the joint part 63Y (contact part 63YT). In this state, a current was passed between the first electrode 141 and the second electrode 146 to resistance weld the foil welded part 12C and the joining part 63Y.

However, the first high level portion 13D of the foil welded portion 12C is stronger in the height direction (stacking direction DT of the positive foil 28) than the first low level portion 13E in the formation process described above. They are not pressed together and do not overlap closely. For this reason, since current is relatively less likely to flow in the stacking direction DT inside the first high level portion 13D, the current flowing through the first high level portion 13D does not travel in the stacking direction DT inside the first high level portion 13D. The first low-order part 13E is advanced through the positive foil 28 located between the first high-order part 13D and the first low-order part 13E and forming the slope 13S, and the first low-order part 13E proceeds in the stacking direction DT (or This route is considered to be reversed). In FIG. 16, the path L along which the current travels is indicated by an arrow. Therefore, at the time of resistance welding, current flows concentrated on the slope 13S around the first low-order part 13E, and the slope 13S and the first low-order part 13E melt.
Further, in order to perform resistance welding by bringing the first high level portion 13D into contact with the positive electrode terminal structure 60, the first high level portion 13D is pressed in the laminating direction DT to form the first high level portion 13D. A part of 28 is pushed out in the spreading direction around the first high-order part 13D. The extruded aluminum (positive electrode foil 28) is also melted at the slope 13S described above.
When the foil welded portion 12C and the positive electrode terminal structure 60 are resistance-welded, nuggets N and N can be generated at each position of the first low-order portion 13E formed on the first foil welded surface 13. Thereby, it is possible to prevent only one nugget from becoming extremely large between the foil welded portion 12C and the positive electrode terminal structure 60, and even if molten aluminum is prevented from being ejected from the nugget N and ejected. Can be kept in a small amount.

  On the other hand, due to the clamping pressure between the first electrode 141 and the second electrode 146, the plurality of second high level portions 14D and 14D are crushed by the first electrode 141 in the stacking direction DT, respectively. The oxide film covering the positive electrode foil 28 is destroyed, and aluminum (new surface) is exposed on the second foil welding surface 14 at a plurality of locations. As a result, the contact resistance between the first electrode 141 and the second foil welding surface 14 is lowered, and since the contact is made at a plurality of locations, the current is dispersed and hardly flows, so in the resistance welding process, Welding between one electrode 141 and the foil welded portion 12C can be prevented.

In the resistance welding process, when the second high level portion 14D is crushed in the stacking direction DT by the first electrode 141, the surrounding portion of the second high level portion 14D moves toward the second low level portion 14E. . As a result, the plurality of positive foils 28 laminated between the second low-order part 14E and the second high-order part 14D are respectively deformed and bent into a U-shaped cross section, and the U-shaped part LU laminated. (See FIG. 16).
As shown in FIG. 5, in the foil welded portion 12C, the nugget N and the U-shaped portion LU are arranged in the stacking direction DT. In the U-shaped portion LU, since a plurality of positive foils 28 are bent and stacked in the stacking direction DT, a gap is generated between the positive foils 28 and 28 and heat is not easily transmitted to the stacking direction DT. In addition, the second foil welding surface 14 can be separated from the nugget N by increasing the dimension in the stacking direction DT as compared with the case where the same number of positive electrode foils 28 are stacked in a flat plate shape.
By these, in a resistance welding process, it can suppress that heat is transmitted from the nugget N to the 2nd foil welding surface 14, and the welding with the 1st electrode 141 and the 2nd foil welding surface 14 can further be suppressed.

  Moreover, since the U-shaped portion LU is located on the second foil welding surface 14 side in the stacking direction DT as viewed from the nugget N, the nugget N is difficult to grow in the stacking direction DT in the U-shaped portion LU. This is because, in the U-shaped portion LU, a gap is generated between the stacked positive electrode foils 28 and 28, so that current does not easily flow in the stacking direction DT. For this reason, the nugget N tends to grow in the spreading direction, and a nugget N having a large area (cross-sectional area) in the spreading direction is interposed at the interface between the positive electrode terminal structure 60 and the positive electrode foil multilayer portion 11 (positive electrode foil welded portion 12). Therefore, the welding strength between the positive electrode terminal structure 60 and the positive electrode foil multilayer portion 11 can be further increased.

  Thus, good welding strength can be ensured between the positive electrode foil multilayer portion 11 and the positive electrode terminal structure 60, and resistance welding can be performed while suppressing adhesion of aluminum from the second foil welding surface 14 to the first electrode 141.

  Subsequently, the other of the joint portions 63Y of the positive electrode terminal structure 60 and the foil welded portion 12C were resistance-welded in the same manner. In this way, the electrode body 10 in which the positive electrode terminal structure 60 is bonded to the positive electrode foil multilayer portion 11 (positive electrode foil welded portion 12) can be obtained.

  On the other hand, the negative electrode terminal structure 70 (negative electrode internal terminal member 71) assembled to the sealing lid 82 by a known method was joined (resistance welding) to the negative electrode plate 30 (negative electrode lead portion 38f) of the electrode body 10. Thereafter, the electrode body 10 integrated with the sealing lid 82, the positive electrode terminal structure 60 and the negative electrode terminal structure 70 is accommodated in the battery case main body 81, and the battery case main body 81 and the sealing lid 82 are separated from each other by laser welding. Join together. Next, after injecting an electrolytic solution into the battery case 80 from a liquid injection hole (not shown), the liquid injection hole is sealed to complete the battery 1 according to Example 1 (see FIG. 1).

By the way, the welding state of the electrode body 10 and the positive electrode terminal structure 60 of the battery 1 according to Example 1 was investigated. Specifically, ten batteries similar to the battery 1 are prepared, and between the positive electrode foil multilayer portion 11 (positive electrode foil welded portion 12) of the resistance-welded electrode body 10 and the joint portion 63Y of the positive electrode terminal structure 60. The weld strength (tensile strength in the shear direction) was measured using a known tensile tester. The results are shown in Table 1. In Table 1, when the weld strength (tensile strength) of all (10 out of 10) is 150 N or more, a “◯” mark is displayed in the weld state column, and the weld strength of 5 or more is less than 100 N. In the case of, “x” mark is given, and in the case of other results, “△” mark is given respectively.
Table 1 also shows whether or not the positive electrode foil is welded to the first electrode 141 during resistance welding. In addition, in 5 or more batteries, “Yes” was indicated when the positive electrode foil was welded during resistance welding, and “None” was indicated otherwise.

(Examples 2 and 3, Reference Examples 1 and 2 , Comparative Examples 1 to 3)
On the other hand, in addition to the batteries of Examples 1 and 3 and Reference Examples 1 and 2 in which the first low-order part and the second low-order part are arranged in the same phase, but different from the battery 1 of Example 1 described above, Each battery of Examples 1 to 3 was prepared.
Specifically, in the battery of Example 2, in the above-described foil welded part forming step, the second depth dimension D2 is D2 = 0.36 mm, and the ratio D2 / D1 is D2 / D1 = 0.90. It differs from the battery 1 of Example 1 in that the part was manufactured by molding (see Table 1).
In addition, the battery of Example 3 was formed with a foil welded portion where the pitch P1 was P1 = 0.70 mm, the second depth dimension D2 was D2 = 0.20 mm, and the ratio D2 / D1 was D2 / D1 = 0.50. Thus, the battery 1 is different from the battery 1 of Example 1 (see Table 1).
In addition, the battery of Reference Example 1 was produced by molding a foil welded portion in which the second depth dimension D2 was D2 = 0.08 mm and the ratio D2 / D1 was D2 / D1 = 0.20. 1 is different from the battery 1 (see Table 1).
In addition, the battery of Reference Example 2 was obtained by molding a foil welded portion in which the second depth dimension D2 was D2 = 0.44 mm and the ratio D2 / D1 was D2 / D1 = 1.10. 1 is different from the battery 1 (see Table 1).
On the other hand, the battery of Comparative Example 1 is a foil welded part in which the first high-order part and the first low-order part are not formed on the first foil weld surface, and the second high-order part and the second low-order part are not formed on the second foil weld surface, respectively. It is a battery made by using.
Further, in the battery of Comparative Example 2, the first low level portion on the first foil welding surface and the second low level portion on the second foil welding surface are not aligned in the stacking direction DT (specifically, the first low level portion and The second low-order part is shifted by 1/2 pitch in the long-diameter direction DL, and the second low-order part is an intermediate part of two first low-order parts adjacent to the long-diameter direction DL on the second foil welding surface. It is a battery made by using a foil welded portion in a form (arranged in a portion corresponding to the stacking direction DT).
Furthermore, the battery of Comparative Example 3 can be made by using a foil welded portion having a form in which the pitch of the first lower portion (0.60 mm) and the pitch of the second lower portion (0.90 mm) on the surface of the first foil weld are different. Battery. In the foil welded part of the battery, a part of the second low-level part overlaps the first low-level part and the stacking direction DT, while the other second low-level part has the first low-level part and the stacking direction DT. It is arranged in a pattern that does not overlap.
For each of the batteries of Examples 2 and 3 and Reference Examples 1 and 2 and the batteries of Comparative Examples 1 to 3, as in the battery 1 of Example 1, the electrode body (positive foil multilayer part) and the positive terminal structure The welded state with the body was investigated, and the results are shown in Table 1. Table 1 also shows whether or not the positive electrode foil is welded to the first electrode 141 during resistance welding.

  According to Table 1, the battery of Comparative Example 1 using the foil welded part in which the first high-order part, the first low-order part, the second high-order part, and the second low-order part are not formed is an electrode body (positive foil multilayer part). ) And the positive electrode terminal structure, and more than half of the positive electrode terminal structures are welded to the first electrode 141 during resistance welding. This is because the first foil welding surface and the second foil welding surface are both flat, the portion where current flows during resistance welding is not determined, and the current concentrates on one portion where the oxide film was first destroyed. Flowing. In addition, since a large current due to the high voltage flows through the electrode body (positive foil multilayer) and the positive terminal structure, only one nugget is likely to increase instantaneously. For this reason, since the thickness of the positive electrode foil multilayer part sandwiching the nugget in the laminating direction becomes thin and easily breaks, a large amount of molten aluminum is easily ejected from the nugget to the outside of the positive electrode foil multilayer part. This is thought to be because it is difficult to ensure the welding strength with the structure.

  Further, in the battery of Comparative Example 2 using the foil welded portion in which the first lower portion and the second lower portion do not overlap in the stacking direction, the welding strength between the positive foil laminated portion and the positive terminal structure is “Δ”. However, as in the battery of Comparative Example 1, the first electrode and the positive electrode foil are welded in more than half. This is because, during resistance welding, the U-shaped portion is not formed on the surface side of the welded DT second foil in the nugget, and the positive electrode foil laminated in a flat plate shape is located, so the heat of the nugget is in contact with the first electrode 141. It is considered that the positive foil was welded to the surface of the second foil.

  In addition, the battery of Comparative Example 3 in which the pitch of the first low-order part and the pitch of the second low-order part are different and a part of the second low-order part is formed using the foil welded part overlapping the first low-order part and the stacking direction DT. In addition, as in the batteries of Comparative Examples 1 and 2, welding of the first electrode and the positive electrode foil occurred in more than half. This is because the U-shaped portion is not formed on the side of the DT second foil weld surface in the stacking direction of some nuggets, and the heat of this nugget is transmitted to the second foil weld surface with which the first electrode 141 is in contact.

On the other hand, the pitch of the first low level part and the pitch of the second low level part are equal, and the first low level part and the second low level part overlap in the stacking direction. In each of the batteries (battery 1) of Examples 1 to 3 and Reference Examples 1 and 2 using the foil welded portion arranged in phase, the “welding strength” is “◯”, and the positive foil layered portion and the positive electrode terminal structure Good welding strength can be secured between the body and the body.

In addition, among the batteries of Examples 1 to 3 and Reference Examples 1 and 2 , Example 1 was made using a foil welded portion in which the ratio D2 / D1 was in the range of 0.3 ≦ D2 / D1 ≦ 0.9. In each of the batteries (batteries 1) to 3, the presence / absence of welding on the first electrode 141 is “none”, and the adhesion of aluminum from the second foil welding surface to the first electrode 141 is reliably suppressed during resistance welding. You can see that it is made.
In the battery of Reference Example 1 in which the ratio D2 / D1 is smaller than 0.3, the U-shaped portion is apt to be crushed small, so that current easily flows there, and the growth of the nugget toward the second foil welding surface side is facilitated. The nugget approaches the electrode contact surface without being suppressed. For this reason, it is considered that the heat of the nugget is easily transmitted to the second foil welding surface during resistance welding, and the first electrode 141 and the second foil welding surface are easily welded.
On the other hand, in the battery of Reference Example 2 using the foil welded portion where the ratio D2 / D1 is greater than 0.9, compared to the batteries of Examples 1 to 3 using the foil welded portion where the ratio D2 / D1 is 0.9 or less. Thus, the contact area between the first electrode 141 and the second foil welding surface is reduced. This is because the first low-order part and the second low-order part both form the bottom of the frustum-shaped recess, and therefore when the first depth dimension D1 is constant and the ratio D2 / D1 increases, the second depth The dimension D2 is increased, and the space surrounded by the frustum-shaped recess including the second low-order part is also increased. This is because the area of the second high-order part forming the second foil welding surface is reduced.
On the other hand, each battery of Examples 1 to 3 is manufactured by using the foil welded portion in which the ratio D2 / D1 is in the range of 0.3 ≦ D2 / D1 ≦ 0.9. At this time, it is possible to manufacture the battery 1 by reliably suppressing aluminum from adhering to the first electrode 141 from the second foil welding surface.

In the above, the present invention has been described with reference to the embodiments (Examples 1 to 3 ). However, the present invention is not limited to the above-described embodiments, and may be appropriately changed without departing from the gist thereof. Needless to say, it can be applied.
For example, in Example 1 or the like, the first low-order part and the second low-order part are the bottoms of the recesses recessed in the shape of a quadrangular pyramid. However, for example, a recess recessed in a truncated cone shape or a recess recessed in a cone shape such as a pyramid (square pyramid) or a cone may be used. Moreover, the 1st low level part and the 2nd low level part were made into the same kind of form (bottom part of the recessed part dented in the shape of a square frustum). However, different forms may be used. Moreover, the example which formed in the form which distributes several 1st low-order part in a grid | lattice form in the joining plan surface was shown. However, the plurality of first low-order portions may be formed by being distributed radially.

DESCRIPTION OF SYMBOLS 1 Battery 10 Electrode body 11 Positive electrode foil multilayer part (foil multilayer part)
12 Positive foil welded part (foil welded part)
13 First foil weld surface (surface to be joined)
13D 1st high level part 13E 1st low level part 14 2nd foil welding surface (electrode contact surface)
14D 2nd high level part 14E 2nd low level part 20 Positive electrode plate 28 Positive electrode foil (aluminum foil)
60 Positive terminal structure (positive terminal member)
141 First electrode (first resistance welding electrode)
146 Second electrode (second resistance welding electrode)
D1 1st depth dimension D2 2nd depth dimension DS Minor axis direction DT Lamination direction LU U-shaped part N Nugget

Claims (3)

An electrode body having a positive electrode plate including an aluminum foil, and having a foil multilayer portion in which the exposed foil portions of the aluminum foil overlap in the stacking direction of the positive electrode plate;
A positive electrode terminal member made of aluminum,
A method for producing a battery in which the foil multilayer portion and the positive electrode terminal member are resistance-welded in the stacking direction,
A foil welded part forming step for forming a foil welded part in which the aluminum foils that overlap each other are welded to each other in the laminating direction by ultrasonic welding on the foil layered part,
A resistance welding step of resistance welding the foil welded part of the electrode body and the positive electrode terminal member,
The foil welded part molding process is as follows:
Located on one side of the laminating direction of the surface of the foil welded portion, at least a part of the planned joining surface to be joined to the positive terminal member
A high first high-order part on one side in the stacking direction;
A plurality of first low-order parts arranged in a dotted pattern in the planned joining surface at a lower position than the first high-order part; and
Located on the other side of the lamination direction of the surface of the foil welded portion, on at least a part of the electrode contact surface that contacts the first resistance welding electrode,
A second high-order portion that is high on the other side in the stacking direction;
Forming a plurality of second low-order parts disposed at positions overlapping with the first low-order part and the stacking direction in the electrode contact surface at a lower position than the second high-order part,
The resistance welding process
The first resistance welding electrode, the foil welded portion, the positive terminal member, and the second resistance welding electrode are stacked in this order, and the second high-order portion is crushed in the stacking direction by the first resistance welding electrode. The second lower portion is formed into a U-shaped portion in which a plurality of the aluminum foils are bent and laminated in a U-shaped cross section , and the first resistance welding electrode and the foil welded portion are welded. A method for manufacturing a battery, wherein a nugget is generated in the first low-order portion with a flowing current while preventing . A battery manufacturing method according to claim 1, comprising:
Each of the first low-order part and the second low-order part of the foil welded part is a form that forms the bottom surface of a frustum-shaped concave part,
Of the foil welded portions, the dimension in the stacking direction from the joining planned surface to the first low-order part is defined as a first depth dimension D1, and the dimension in the stacking direction from the electrode contact surface to the second low-order part is set. When the dimension is the second depth dimension D2,
The battery manufacturing method, wherein a ratio D2 / D1 between the second depth dimension D2 and the first depth dimension D1 is in a range of 0.3 ≦ D2 / D1 ≦ 0.9. An electrode body having a positive electrode plate including an aluminum foil, and having a foil multilayer portion in which the exposed foil portions of the aluminum foil overlap in the stacking direction of the positive electrode plate;
A positive electrode terminal member made of aluminum,
The foil multi-layer part and the positive electrode terminal member are
In between heavy Naru the foil layer portion and the positive terminal member in the stacking direction, it is coupled via a plurality of nuggets distributed in unevenness distribution in the spreading direction of the aluminum foil,
Each of the portions where the nugget is present on the positive electrode terminal member side in the laminating direction in the foil multilayer portion is a U-shaped portion in which a plurality of the aluminum foils are bent and laminated in a U-shaped cross section. Battery.

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