JP7359730B2 - Secondary battery manufacturing method and secondary battery - Google Patents

Description

The present invention relates to a method for manufacturing a secondary battery and a secondary battery.

Some secondary batteries have a structure in which a separator is sandwiched between a positive electrode sheet and a negative electrode sheet to form a power generating body. Further, the battery capacity of a secondary battery is determined by the size of the area of the power generating body. In the case of secondary batteries, various methods of storing a power generating body within the secondary battery have been considered in order to increase the battery capacity per volume of one secondary battery (hereinafter referred to as capacity efficiency). One of the storage methods is a rolled structure in which a sheet-like power generating body with a large area is rolled up into a cylindrical shape. Further, as another storage method, there is a laminated structure in which a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators are stacked with the separator sandwiched between the positive electrode sheet and the negative electrode sheet.

In a secondary battery, one of the factors that influences capacity efficiency is how to reduce the volume required for a current collection component that bundles sheets that constitute a current collector and extracts power from the current collector. However, when increasing the volumetric efficiency, it is also necessary to consider the bonding strength between the current collector and the current collecting component.

Patent Document 1 describes a power storage device that aims to improve weldability between a tab group and a conductive member. The power storage device described in Patent Document 1 includes an electrode assembly in which electrodes having a tab protruding from one side are stacked, a tab group configured by stacking the tabs, a case housing them, and a case. It includes an electrode terminal that is fixed to the lid and that transmits and receives electricity to and from the electrode assembly, and a conductive member.

This conductive member is a metal plate member that electrically connects the tab group and the electrode terminal, and includes a base portion located at a position overlapping the lid body, and a connecting portion continuous with the base portion and to which the tab group is joined. It is fixed to the inner surface of the lid that seals the opening of the case via an insulating cover. Here, the width of the connecting portion is smaller than the width of the base, the tab group is spaced apart from the base in the continuous direction, and the tip of the connecting portion protrudes from the tab group in the continuous direction. Note that the direction in which the conductive members are connected is a direction in which the base and the connecting portion are lined up, and the width direction of the conductive members is a direction along the surface of the base and perpendicular to the direction in which they are connected. Further, the above-mentioned electrode terminal has an external terminal, a rectangular flat connecting conductor, and an auxiliary terminal fixed to the lid, and the auxiliary terminal has a first caulking part that connects to the conductive member by caulking, It has a second caulking part that performs connection by caulking with the connecting conductor. The connection conductor has a pole part insertion hole into which the pole part of the external terminal is inserted from the lid side. The connection conductor and the conductive member are connected by the first and second caulking portions of the auxiliary terminal, with a portion of the external terminal and the lid disposed between them.

Unexamined Japanese Patent Publication No. 2018-107009

However, in the power storage device described in Patent Document 1, due to its structure, the connecting conductor and the second caulking part are joined on the lid side of the case, the conductive member is joined to the tab group protruding from the electrode assembly, and then, It is necessary to join the conductive member to the first caulking part. That is, the power storage device described in Patent Document 1 requires an auxiliary terminal for caulking connection in addition to the conductive member, and also requires a three-step joining process.

The present invention has been made to solve such problems, and its purpose is to improve the bonding strength when bonding the lid member that seals the case of the secondary battery, the current collector component, and the electrode body. An object of the present invention is to provide a method for manufacturing a secondary battery and a secondary battery that can reduce the number of bonding steps while maintaining the same characteristics.

A method for manufacturing a secondary battery according to one embodiment of the present invention includes a tab portion that has an active material region coated with an active material and a region not coated with the active material and has a shape protruding from the active material region. a lamination step of laminating a plurality of electrode sheets with a separator between each electrode sheet to form a laminate; and a storage step of storing the laminate in a case having an opening from the opening. and a sealing step of attaching a lid member to the opening and sealing the case, joining a bundle of the plurality of tab portions of the electrode sheets having the same polarity to a current collecting component. , further comprising an attachment step of attaching the current collecting component to a lid member that closes the opening, the current collecting component includes a flat current collecting portion joined to the bundle of tab portions, and a surface side of the lid member. a plate-like member having a planar electrode connection part that connects to the extraction electrode from the back side of the lid member, and a connection part that connects the current collector and the electrode connection part; In the attaching step, the electrode connecting portion is connected to the take-out electrode, and the bundle of tab portions is joined to the current collecting portion, so that the current collecting portion and the electrode connecting portion are approximately parallel to each other with a gap in between. The connecting portion is bent as shown in FIG.

In the method for manufacturing a secondary battery according to this aspect, when joining a lid member for sealing a case, a current collector component, and a laminate, a single plate-like member is used to connect a bundle of takeout electrodes and tab parts. After joining, the plate-like members are bent. This makes it possible to reduce the number of bonding steps while maintaining bonding strength.

Further, it is preferable that the connecting portion is bent so that the current collecting portion and the electrode connecting portion are substantially perpendicular to each other before the attaching step is performed. Thereby, the attachment process can be carried out more easily than when working from a state in which the plate-like members are parallel to each other.

Further, the width direction of the tab portion is defined as a first direction, the width of the current collecting portion in the first direction is longer than the width of the electrode connection portion in the first direction, and the attaching step is performed on the tab portion. After the bundle is joined and before the connection part is bent, an insulator is positioned between the current collector part to which the bundle of tab parts is joined after bending and the back surface of the lid member, It is preferable that the insulator is provided and the connection portion is bent. Thereby, the insulator can be easily provided during the manufacturing process.

Further, it is preferable that the storing step is performed after the bundle of tab portions is joined to the current collecting portion in the attaching step. Thereby, the current collecting component and the extraction electrode can be joined in advance at another location, and the possibility of foreign matter contamination can be reduced.

The width direction of the tab portion is a first direction, and the width of the connecting portion in the first direction is shorter than the width of the electrode connecting portion in the first direction and the width of the current collecting portion in the first direction. Short is preferable. Thereby, the plate-like member can be easily bent.
Further, it is preferable that the thickness of at least the bent portion of the connecting portion is thinner than the thickness of the current collecting portion and thinner than the thickness of the electrode connecting portion. Thereby, the plate-like member can be easily bent.

Further, the current collecting component includes a caulking member having a columnar member passing through a hole provided in the lid member, and in the attaching step, the caulking member is attached with the columnar member passing through the hole. It is preferable that the bonding be performed at Thereby, the electrode connection portion and the lid member can be joined only on the lid member side.
Further, the laminate is a laminate having a wound structure that is housed in the case in a wound state, and the tab portion of the electrode sheet of one polarity protrudes from one end of the wound body. The tab portion of the electrode sheet of the other polarity may have a shape protruding from the other wound end portion.

A secondary battery according to another aspect of the present invention includes an active material region coated with an active material and a tab portion having a shape protruding from the active material region where the active material is not coated. a laminate in which a plurality of electrode sheets are stacked with a separator interposed between each electrode sheet; a current collector component joined to a bundle of the plurality of tab portions of the electrode sheets having the same polarity; and an opening. and a case for storing the laminate; and a lid member attached to the opening to seal the case; a current collector, a planar electrode connection part that connects to the extraction electrode on the front surface of the lid member from the back side of the lid member, and a connection part that connects the current collector and the electrode connection part. The strength of the connecting portion is lower than the strength of the current collecting portion and the strength of the electrode connecting portion, and the current collecting portion and the electrode connecting portion are sandwiched with a gap. The opening portion is sealed by the lid member in a state in which the connecting portion is bent so as to be substantially parallel to each other.

In the secondary battery according to this aspect, when joining the lid member for sealing the case, the current collector component, and the laminate, a single plate-like member is used to join the bundle of the extraction electrode and the tab part, After that, the plate member is bent. This makes it possible to reduce the number of bonding steps while maintaining bonding strength.

Further, the width direction of the tab portion is a first direction, and the width of the connection portion in the first direction is shorter than the width of the electrode connection portion in the first direction, and the width of the current collection portion in the first direction is shorter than the width of the electrode connection portion in the first direction. Preferably shorter than the width. Thereby, the plate-like member can be easily bent.

Further, it is preferable that the thickness of at least the bent portion of the connecting portion is thinner than the thickness of the current collecting portion and thinner than the thickness of the electrode connecting portion. Thereby, the plate-like member can be easily bent.

Further, the width direction of the tab portion is a first direction, the width of the current collecting portion in the first direction is longer than the width of the electrode connecting portion in the first direction, and when the connecting portion is bent, Preferably, an insulator is provided between the current collector to which the bundle of tab parts is joined and the back surface of the lid member. Thereby, the insulator can be easily provided during the manufacturing process.

Further, it is preferable that the current collecting component includes a caulking member, and the caulking member includes a columnar member formed in the electrode connection portion and passing through a hole provided in the lid member. Thereby, the electrode connection portion and the lid member can be joined only on the lid member side.
Further, the laminate is a laminate having a wound structure that is housed in the case in a wound state, and the tab portion of the electrode sheet of one polarity protrudes from one end of the wound body. The tab portion of the electrode sheet of the other polarity may have a shape protruding from the other wound end portion.

According to the present invention, a secondary battery is manufactured that can reduce the number of bonding steps while maintaining bonding strength when bonding a lid member that seals a secondary battery case, a current collector component, and an electrode body. A method and a secondary battery can be provided.

1 is a diagram showing an example of the appearance of a secondary battery according to an embodiment. FIG. 2 is a flow diagram for explaining an example of a method for manufacturing a secondary battery according to an embodiment. FIG. 2 is a perspective view showing an example of a laminate housed in the case of the secondary battery shown in FIG. 1. FIG. FIG. 2 is an exploded view showing an example of a current collector component of the secondary battery of FIG. 1 and its mounting member. 5 is a diagram illustrating an example of a positive electrode current collector component included in the current collector component of FIG. 4. FIG. 6 is a diagram for explaining a method of processing the positive electrode current collector component of FIG. 5. FIG. FIG. 2 is a perspective view showing how a current collector component is attached to the lid in the manufacturing process of the secondary battery shown in FIG. 1. FIG. 2 is a perspective view for explaining the manufacturing process of the secondary battery of FIG. 1. FIG. 9 is a perspective view for explaining an example of the manufacturing process following FIG. 8. FIG. 10 is a perspective view for explaining the manufacturing process following FIG. 9. FIG. 11 is a perspective view for explaining the manufacturing process following FIG. 10. FIG. 12 is a perspective view showing an example of an insulator used in FIG. 11. FIG. 10 is a perspective view for explaining another example of the manufacturing process following FIG. 9. FIG. 11 is a perspective view for explaining another example of the manufacturing process following FIG. 10. FIG. 10 is a perspective view for explaining another example of the manufacturing process following FIG. 9. FIG. 12 is a perspective view for explaining the manufacturing process following FIG. 11. FIG. 17 is a perspective view for explaining the manufacturing process following FIG. 16. FIG.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and drawings are simplified as appropriate. Further, in the embodiments, the same or equivalent elements may be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

(Embodiment)
An embodiment will be described with reference to FIGS. 1 to 17. FIG. 1 is a diagram showing an example of the appearance of a secondary battery according to an embodiment.

As shown in FIG. 1, the secondary battery 1 according to the present embodiment includes a case 10, a lid member (lid) 11, a negative pole 12, and a positive pole 13. Note that a plurality of secondary batteries 1 shown in FIG. 1 can be combined to form an assembled battery, and the secondary battery 1 can be one cell of the assembled battery.

The case 10 houses a power generating body that stores electrical energy of a secondary battery. The lid 11 is a lid for sealing the power generator in the case 10, and has a shape that allows the case 10 to be sealed by being attached to an opening provided in the case 10 with the power generator housed therein. The case 10 and the lid 11 can be made of, for example, aluminum or an alloy thereof.

The negative electrode pole 12 and the positive pole pole 13 are electrodes that are electrically connected to the power generating body in the case 10 and input and output current to and from the power generating body. Further, in the secondary battery 1 , a negative electrode pole 12 and a positive pole pole 13 are provided so as to protrude from the case 10 .

Although not shown in FIG. 1, in the secondary battery 1, a take-out hole is provided in the lid 11 for taking out the negative electrode pole 12 and the positive pole pole 13, which are attached to the power generator stored in the case, out of the case. . Then, the negative electrode pole 12 and the positive pole pole 13 are joined to a current collecting component provided in the case 10 through a take-out hole provided in the lid 11.

One of the features of this embodiment is the method of manufacturing the secondary battery 1, in which a stacked body functioning as a power generator is housed in the case 10, and a current collecting component is attached thereto, and the shape of the current collecting component. Therefore, in the following, an example of the structure of the current collector component will also be described while explaining an example of the method for manufacturing the secondary battery 1 along the flow shown in FIG. FIG. 2 is a flow diagram for explaining an example of a method for manufacturing the secondary battery 1. As shown in FIG.

The manufacturing method according to the present embodiment (hereinafter referred to as the present manufacturing method) may include a laminating process (step S1), an attaching process (step S2), a housing process (step S3), and a sealing process (step S4). can.

First, the lamination process of step S1 will be briefly explained with reference to FIG. FIG. 3 is a perspective view showing an example of a laminate housed in the case 10 of the secondary battery 1.

In the lamination step of step S1, a plurality of electrode sheets are laminated with a separator interposed between each electrode sheet to form a laminated body (laminated electrode body) 20. Although the details of each electrode sheet are not illustrated or explained, each electrode sheet has an active material area coated with an active material and an area uncoated with the active material, which has a shape protruding from the active material area. It has a section and a.

The electrode sheet includes a positive electrode sheet serving as a positive electrode and a negative electrode sheet serving as a negative electrode. For example, the positive electrode sheet is coated with active materials such as LiCoO ₂ , LiMn ₂ O ₄ , LiNiO _{2 ,} and the like. Further, the negative electrode sheet is coated with, for example, graphite (C), titanate (Li ₄ Ti ₅ O1 ₂ ), or the like as an active material.

In order to function as a power generating body, in the laminate 20, positive electrode sheets and negative electrode sheets are alternately laminated such that the active material region of the positive electrode sheet and the active material region of the negative electrode sheet are overlapped. The separator is provided so as to be sandwiched between the positive and negative active material regions. A separator can also be laminated on the electrode plate (positive electrode sheet or negative electrode sheet) on the outside of one or both ends of the laminate 20. Note that the number of positive electrode sheets and the number of negative electrode sheets does not matter. The lamination direction of the laminate 20 can be the direction shown in FIG.

Further, in the secondary battery 1, a plurality of tab portions of electrode sheets having the same polarity are bundled. Specifically, the positive electrode tab portion 21p of the positive electrode sheet and the negative electrode tab portion 21n of the negative electrode sheet are individually bundled. For example, in the stacking direction of a plurality of electrode sheets and a plurality of separators (vertical direction in FIG. 3), an electrode sheet located at one end of the laminate 20 (the lowest sheet in FIG. 3) Bundle the tabs together on the side. Both the positive electrode tab portion 21p and the negative electrode tab portion 21n are bonded to the current collecting component in the attachment process in a bundled state. The following description will be made on the assumption that the positive electrode tab portion 21p and the negative electrode tab portion 21n are both in a bundled state.

In this way, the laminate 20 can have a structure in which a plurality of electrode sheets and a plurality of separators are stacked. An adhesive or the like may be used between the members during lamination. Further, in the lamination step, the volume density of the laminated body 20 can be improved by applying pressure to both sides of the laminated body 20. Further, the laminate 20 can be wrapped around the periphery with a tape made of PP (polypropylene) or the like to solidify the shape of the laminate 20, thereby making it easier to insert it into the case 10.

In the attachment process of step S2, a bundle of a plurality of tab parts of the electrode sheet having the same polarity (positive electrode tab part 21p, negative electrode tab part 21n) is joined to the current collector component, and a lid 11 that closes the opening of the case 10 is attached. Attach the current collecting parts to.

Here, an example of the current collector component and a method of attaching it to the lid 11 will be described with reference to FIGS. 4 to 7. FIG. 4 is an exploded view showing an example of a current collector component of the secondary battery 1 and its mounting member. Note that FIG. 4 shows a state in which the stacked body 20 is not housed in the case 10 before the current collector components are assembled. 5 is a diagram showing an example of the positive electrode current collector component 22p of FIG. 4, and FIG. 6 is a diagram for explaining a method of processing the positive electrode current collector component 22p of FIG. 5. FIG. 7 is a perspective view showing how the current collector component is attached to the lid 11 during the manufacturing process of the secondary battery 1.

This current collecting component is a component having conductivity, and includes a positive current collecting component 22p and a negative current collecting component 22n, which will be described later. The positive electrode current collector component 22p and the negative electrode current collector component 22n are joined to the positive electrode tab portion 21p and the negative electrode tab portion 21n, respectively. Further, both the positive electrode current collector component 22p and the negative electrode current collector component 22n are joined to the pedestal 23 and the extraction electrode (positive electrode pole 13 and negative pole pole 12, respectively) via the lid 11. Laser welding, ultrasonic bonding, or the like can be used for these bonds.

The negative pole pole 12 and the positive pole pole 13 are each provided on a pedestal 23. This pedestal 23 is brought into close contact with the lid 11 and improves the sealing performance after the laminate 20 is housed in the case 10. The positive pole pole 13 and the pedestal 23 on the positive pole side are electrically connected, and the negative pole pole 12 and the base 23 on the negative pole side are also electrically connected. Although not shown in FIG. 4, an insulator is provided between the pedestal 23 and the lid 11.

The positive electrode current collecting component 22p is assumed to have a single plate-like member having a planar current collecting portion 22p_3, a planar electrode connecting portion 22p_1, and a connecting portion 22p_2. Note that, although only the positive electrode current collector component 22p will be described below, the negative electrode current collector component 22n also has a single plate-like member having a current collector portion, an electrode connection portion, and a connection portion, similarly to the positive electrode current collection component 22p. be able to.

The current collecting portion 22p_3 is a portion that is joined to the bundled positive electrode tab portion 21p, that is, a portion that is joined to the stacked body 20 side and performs current collection. As shown in FIG. 4, the positive electrode tab part 21p can be joined in a folded state from one side of the current collecting part 22p_3 to the opposite side, and although not shown, the folded side can be fixed with tape such as PP, etc. You can also leave it there. In this case, the joint portion can be only on the one side. Alternatively, the positive electrode tab portion 21p may be joined to one surface of the current collecting portion 22p_3 without performing such folding.

The electrode connecting portion 22p_1 is a member that connects to the extraction electrode (electrode terminal) on the front surface side of the lid 11 from the back side of the lid 11. More specifically, the electrode connection portion 22p_1 can be a portion that is arranged on the back side of the lid 11 via the insulator 25p and connected to the positive electrode pole 13, which is the extraction electrode on the positive electrode side. Further, the connecting portion 22p_2 is a portion that connects the current collecting portion 22p_3 and the electrode connecting portion 22p_1.

As shown in FIG. 4, the positive electrode current collector component 22p is bent in a state where the connection portion 22p_2 is bent so that the current collection portion 22p_3 and the electrode connection portion 22p_1 are substantially perpendicular (that is, in an L-shape), as shown in FIG. It is preferable that the shape be the same, and an example of this will be given below. Note that "substantially perpendicular" can include a range of angles that can be considered perpendicular, and similarly, "substantially parallel" in the following description can include a range of angles that can be considered parallel.

By molding a flat positive electrode current collector component 22p as shown in the upper part of FIG. 5 and bending it at the connection part 22p_2, an L-shaped positive electrode current collector part 22p as shown in the lower part of FIG. 5 is formed. can be formed. Alternatively, the positive electrode current collector component 22p may be originally formed into an L-shape as shown in the lower part of FIG. Note that the view of the positive electrode current collector component 22p in the lower part of FIG. 5 viewed from the left side of the page is as shown in the upper part of FIG. 6.

In the attachment process, first, the electrode connection portion 22p_1 is connected to the positive electrode pole 13. Specifically, as shown in FIG. 4, the positive electrode current collector component 22p is disposed on one surface of the lid 11 via an insulator 25p, and the pedestal 23 and the positive electrode pillar 13 are disposed on the other surface of the lid 11. will be arranged. The positive electrode current collector component 22p is electrically connected to the positive electrode pole 13 at the electrode connection portion 22p_1 by caulking members 24a and 24b that penetrate the lid 11. The electrode connection part 22p_1 corresponds to a mounting part to which the caulking members 24a and 24b are attached.

Here, as shown in FIG. 4, the electrode connection portion 22p_1 is provided with a hole 24c, and the lid 11 is provided with a hole 24d. Further, the pedestal 23 is provided with a hole 24e, and the insulator 25p is provided with a hole 24f. When assembling the secondary battery 1, the caulking member 24a is passed through the holes 24c, 24f, 24d, and 24e, and the positive electrode current collector component 22p, the lid 11, and the pedestal 23 are caulked by the caulking member 24a and the caulking member 24b. Join by doing this. Here, the caulking member 24a is provided with a head having a larger diameter than the hole 24c as shown in the figure, so that the electrode connecting portion 22p_1 and the pedestal 23 on the lid 11 side can be joined by welding or the like only on the caulking member 24b side (i.e. (only on the top side of the lid 11). Moreover, the caulking member 24a and the electrode connection part 22p_1 may be integrally formed members, and in that case, the hole 24c does not exist in the electrode connection part 22p_1.

In this way, the positive electrode current collector component 22p can have the following caulking member. This caulking member has a columnar member that passes through a first hole 24d provided in the lid 11 and a second hole 24c provided in the electrode connection portion 22p_1, and a head portion having a larger diameter than the first hole 24d. It can be a caulking member 24a. When the second hole 24a is not provided, this caulking member can have a columnar member formed in the electrode connection portion 22p_1 that passes through the hole 24d provided in the lid 11. Regardless of which caulking member is used, in the attachment process, the columnar member can be joined from the pedestal 23 side with the columnar member penetrating the hole 24d of the lid 11. In addition, in the attachment process, joining was performed from the pedestal 23 side, but if the structure allows joining from the surface side of the lid 11, attachment can be easily performed. However, in the attachment process, it is also possible to join from the back side of the lid 11. In that case, the positions of the caulking member 24a and the caulking member 24b in FIG. It is also possible to adopt a configuration in which the columnar member is integrated with the pedestal 23 without providing the columnar member.

By performing such work not only on the positive electrode current collecting component 22p side but also on the negative electrode current collecting component 22n side, a state as shown in FIG. 7 is obtained. Note that FIG. 7 shows an example in which a release valve 27 and a liquid injection port 28 are provided. The release valve 27 is a valve for releasing the gas inside the case 10 when the internal pressure inside the case 10 increases to a preset pressure or higher while the case 10 is in a sealed state.

In this way, by assembling the current collector component and the pole pole as separate components, workability during joining can be improved. Further, by integrating the negative electrode current collector component 22n, the positive electrode current collector component 22p, the negative electrode pole 12, and the positive pole pole 13 using the lid 11, the workability of subsequent steps can be improved.

The subsequent manufacturing process will be explained with reference to FIGS. 8 to 17. 8 to 11, FIG. 16, and FIG. 17 are perspective views for explaining an example of the manufacturing process of a series of secondary batteries 1, and FIG. 12 is a perspective view showing an example of the insulator used in FIG. It is. Moreover, FIG. 13 is a perspective view for explaining another example of the manufacturing process following FIG. 9. FIG. 14 is a perspective view for explaining still another example of the manufacturing process following FIG. 10, and FIG. 15 is a perspective view for explaining still another example of the manufacturing process following FIG. 9.

First, with reference to FIGS. 8 to 12, an example of the manufacturing process of the secondary battery 1 up to before closing the lid 11 will be described.

In the attachment process, after connecting the electrode connection part 22p_1 to the positive electrode pole 13 as described above, the positive electrode tab part 21p is joined to the current collecting part 22p_3 in a state as shown in FIG. At this time, the negative electrode tab portion 21n is also joined to the current collecting portion 22n_3. As described above, laser welding, ultrasonic bonding, etc. can be used for this joining, but since the laminate 20 is not housed in the case 10 at this stage, it is necessary to prevent metal foreign matter from entering the case 10. I can do it. Furthermore, by placing the parts on a workbench as shown in FIG. 8 and joining them, joining can be easily performed from above. Note that when the back side portion of the current collecting portion 22p_3 in FIG. 8 is also bonded to the positive electrode tab portion 21p, it can be done in an upside-down state.

By joining the positive electrode tab portion 21p and the negative electrode tab portion 21n to the current collecting portions 22p_3 and 22n_3, respectively, in this manner, a state as shown in FIGS. 8 and 9 is obtained.

In the attachment process, after the positive electrode tab part 21p and the negative electrode tab part 21n are joined, the connecting part 22p_2 is bent so that the current collecting part 22p_3 and the electrode connecting part 22p_1 are approximately parallel to each other with a gap in between, and the negative electrode side is also bent at the same time. Fold it in the same way (fold it approximately 90° in the direction of the white arrow in FIG. 9) to form the state shown in FIG. 10. The result of such bending is illustrated in the lower part of FIG. 6 only for the positive electrode current collector component 22p, and the above-mentioned gap becomes the portion illustrated as the clearance Df. Note that the attachment process may be performed on the connecting portion 22p_2 in a flat state as shown in the upper part of FIG. 5, and in that case, the bending angle in the attachment process will be approximately 180°. In the former case, the positive current collector component 22p and negative current collector component 22n are bent from an L-shape to a U-shape, and in the latter case, the positive current collector component 22p and negative current collector component 22n are bent from an I-shape to a U-shape. It will be folded into a letter shape.

Next, in the installation process, the insulator 26 is inserted from the upper side of FIG. Insert it between the That is, in the attachment process, after bonding the positive electrode tab portion 21p and the negative electrode tab portion 21n, and bending the connecting portions 22p_2 and 22n_2, the current collecting portion 22p_3 and the negative electrode tab portion 21n to which the positive electrode tab portion 21p is bonded are bonded. An insulator 26 is disposed between the back surface of the lid 11 and the current collecting portion 22n_3 to which the insulator 22n_3 is bonded.

Here, the illustrated insulator 26 will be explained. As shown in FIG. 12, the insulator 26 can be a plate-shaped member, and its length can be made slightly shorter than the length between the electrode connecting parts 22p_1 and 22n_1 of the two electrodes. Further, the insulator 26 can be provided with holes 26b and 26c at positions corresponding to the release valve 27 and the liquid injection port 28, respectively, for exposing them to the inside of the lid 11. Further, the insulator 26 can be provided with recesses 26dp and 26dn and protrusions 26ep and 26en for positioning the positive electrode side and the negative electrode side inside the lid 11 at both ends in the longitudinal direction. The concave portion 26dp and the convex portion 26ep, the concave portion 26dn and the convex portion 26en correspond to the convex portions 11ap and 26en provided for positioning, respectively, on the positive electrode side and the negative electrode side inside the lid 11, as shown in FIG. It has a shape that fits into or engages with the recess 11bp, the projection 11an, and the recess 11bn. Further, the insulator 26 has one end in the short direction (both ends may be used, but it is preferable to keep one lower for insertion) of the insulator 26 at both ends in the longitudinal direction so as to be aligned with the inner wall of the opening of the case 10. It can include protrusions 26fp and 26fn. Furthermore, since the insulator 26 is a single member and has projections and depressions for positioning, it is possible to prevent the insulator 26 from being misaligned with respect to other members such as the lid 11.

As shown in FIG. 11, the insulator 26 is arranged so that the positive electrode tab portion 21p and the negative electrode tab portion 21n are located near the longitudinal positions where the protruding portion 26fp and the protruding portion 26fn are provided, respectively. be able to. Further, the insulator 26 can be provided not only after the positive electrode tab portion 21p and the negative electrode tab portion 21n are joined to the current collectors 22p_3 and 22n_3, but also before the positive electrode tab portion 21p and the negative electrode tab portion 21n are joined.

The width direction of the positive electrode tab portion 21p will be described as a first direction. The concave portion 26dp and convex portion 26ep side of the insulator 26 may be disposed between the current collector portion 22p_3 to which the positive electrode tab portion 21p is joined and the back surface of the lid 11 when the connecting portion 22p_2 is bent. can. At the same time, the concave portion 26dn and convex portion 26en side of the insulator 26 are disposed between the current collecting portion 22n_3 to which the negative electrode tab portion 21n is joined and the back surface of the lid 11 in a state where the connecting portion 22n_2 is bent. be able to.

In this case, the insulator 26 can be inserted and disposed between the current collector 22p_3 and the back surface of the lid 11 and between the current collector 22n_3 and the back surface of the lid 11. Since there is a gap equal to the thickness of the gap minus the thickness of the positive electrode tab part 21p (thickness of the negative electrode tab part 21n), it can be inserted into the gap. In this example, the width Wc of the current collector 22p_3 in the first direction is equal to the width Wa of the electrode connection part 22p_1 in the first direction, as illustrated in FIG. be longer. The width Wc of the current collecting portion 22n_3 in the first direction is also longer than the width Wa of the electrode connecting portion 22n_1 in the first direction. Further, the heights of the protrusions 11ap, 11an of the lid 11 and the protrusions 26ep, 26en of the insulator 22 may be determined to such an extent that they do not interfere with insertion of the insulator 26.

Next, with reference to FIG. 13, another example of the manufacturing process following FIG. 9 and before closing the lid 11 will be described. In the installation process of this example, after the positive electrode tab part 21p and the negative electrode tab part 21n are joined (in the state shown in FIG. 9), the insulator 26 shown in FIG. can be put into a state. After that, in the attachment process of this example, the connecting portions 22p_2 and 22n_2 can be bent to be in the state shown in FIG. 11. Note that when arranging them, a jig or the like may be used to maintain the arranging state.

In this example as well, as in the example of FIG. 10, the connection part 22p_2 is bent so that the current collector part 22p_3 and the electrode connection part 22p_1 are approximately parallel to each other with a gap in between, and the negative electrode side is also bent in the same way (as shown in FIG. 13). (Fold in the direction of the white arrow) to make it into the state shown in FIG. 11. In this example as well, the positive electrode current collector component 22p and the negative electrode current collector component 22n may be bent from an L-shape to a U-shape, or from an I-shape to a U-shape. In the case of the example shown in FIG. 13, the insulator 26 has protrusions 26fp at both ends in the longitudinal direction (both ends may be at the same height) for alignment with the inner wall of the opening of the case 10. , 26fn.

Next, with reference to FIG. 14 and FIG. 15, the lid 11 following FIG. 10 and FIG. Two other examples of the manufacturing process up to closing will be explained. In both of the two examples described here, instead of the insulator 26 shown in FIG. 12, as shown in FIG. do. Compared to the two examples described here, it is easier to manufacture the secondary battery 1 in the example using the insulator 26 shown in FIG. 12.

In the mounting process in the example described with reference to FIG. 14, after the positive electrode tab portion 21p and the negative electrode tab portion 21n are joined, the positive electrode current collector component 22p and the negative electrode current collector component 22n are first bent into a U-shape (white in FIG. 9). 10). In addition, also in this example, the positive electrode current collector component 22p and the negative electrode current collector component 22n may be bent from an I-shape to a U-shape.

Thereafter, in the mounting process in this example, the insulators 26p and 26n are inserted and arranged between the positive electrode current collector component 22p and the negative electrode current collector component 22n, respectively, and the back surface of the lid 11, and the state shown in FIG. Make it. Note that the insulator 26p and the insulator 26n may be attached or placed before the positive electrode tab portion 21p and the negative electrode tab portion 21n are respectively joined to the current collector portion 22p_3.

The insulator 26p will be described with the width direction of the positive electrode tab portion 21p as the first direction. Note that the insulator 26n is also similar to the insulator 26p. The insulator 26p can be inserted between the back surface of the lid 11 and the current collecting part 22p_3 to which the positive electrode tab part 21p is joined in a state where the connecting part 22p_2 is bent. In this example as well, the insulator 26p is required at such a position on the premise that the width Wc of the current collector 22p_3 in the first direction is equal to the width Wa of the electrode connection part 22p_1 in the first direction as illustrated in FIG. be longer.

Further, the insulator 26p can have an L-shape including a first surface that covers a part of the current collector 22p_3 to which the positive electrode tab portion 21p is joined, and a second surface that is substantially perpendicular to the first surface. The second surface can be provided with an elongated hole into which the tip side (the tip side in the lateral direction in FIG. 14) of the current collector 22p_3 can be inserted. The insulator 26p can be inserted and disposed between the current collector 22p_3 and the back surface of the lid 11, but the gap is equal to the thickness of the gap indicated by the clearance Df minus the thickness of the positive electrode tab portion 21p. exists, so the first surface can be inserted into the gap.

In the mounting process in the example described with reference to FIG. 15, after the positive electrode tab portion 21p and the negative electrode tab portion 21n are bonded (after they are brought into the state shown in FIG. 9), the insulators 26p and 26n are respectively attached to the positive electrode current collector component 22p and the negative electrode tab portion 21n. Either they are attached to the negative current collector 22n, or they are maintained in the position of the positive current collector 22p and the negative current collector 22n by using a jig or the like. As a result, a state as shown in FIG. 15 is created. In other words, in the attachment process in this example, after the positive electrode tab part 21p is joined and before the connecting part 22p_2 is bent, the current collecting part 22p_3, to which the positive electrode tab part 21p is joined after the bending, is connected to the back surface of the lid 11. The insulator 26p is arranged so that the insulator 26p is located between them. The insulator 26p can be easily attached to such a position by, for example, inserting the tip of the current collector 22p_3 into the elongated hole. The same applies to the insulator 26n on the negative electrode side. Note that the insulator 26p and the insulator 26n may be attached or placed before the positive electrode tab portion 21p and the negative electrode tab portion 21n are respectively joined to the current collector portion 22p_3.

Thereafter, in the attachment process in this example, the positive electrode current collector component 22p and the negative electrode current collector component 22n are bent into a U-shape to form the state shown in FIG. 14. In addition, also in this example, the positive electrode current collector component 22p and the negative electrode current collector component 22n may be bent from an I-shape to a U-shape.

The attachment process of step S2 is carried out as described above. In the subsequent storage process of step S3, the laminate 20 is stored in the case 10 from its opening. Specifically, by bending the positive electrode tab portion 21p and the negative electrode tab portion 21n from the state shown in FIG. 11, the state shown in FIG. After covering with a film (not shown), the laminate 20 is inserted into the case 10 from the opening of the case 10, as shown in FIG. Note that the positive electrode tab portion 21p and the negative electrode tab portion 21n are bent so that the negative electrode pole 12 and the positive electrode pole 13 protrude in a direction substantially parallel to the laminated surface of the laminate 20. Although the explanation is omitted, the state shown in FIG. 16 can also be obtained by bending the positive electrode tab part 21p and the negative electrode tab part 21n from the state shown in FIG. 14 (however, insulators 26p and 26n are used instead of insulator 26) It can be done.

In the sealing step of step S4, the case 10 is sealed by attaching the lid 11 to the opening. This attachment can be performed by joining, for example, by laser welding. Thereby, the lid 11 seals the case 10 with the current collecting component provided on one surface (back surface) and the extraction electrode attached to the other surface (front surface). At this time, the opening of the case 10 is sealed with the lid 11 in the following state. That is, in the sealed state, the connection part 22p_2 is bent so that the current collection part 22p_3 and the electrode connection part 22p_1 are approximately parallel to each other with a gap in between, and the current collection part 22n_3 and the electrode connection part 22n_1 are bent. The connecting portion 22n_2 is bent so as to be substantially parallel with a gap in between.

In addition, in order to make the laminate 20 function as a power generating body, a non-aqueous electrolyte such as an organic solvent is injected into the laminate 20 from the liquid injection port 28 of the lid 11 while the laminate 20 is housed in the case 10. Impregnate. The laminate 20 can function as a power generator by impregnating the laminate 20 with a non-aqueous electrolyte from the end face of the laminate 20 through between the electrode plates and the separator. In addition, when the liquid injection port 28 is provided, the liquid injection port 28 may be sealed with a cap or the like after that. The liquid injection port 28 may not be provided, and in that case, the non-aqueous electrolyte can be injected from the opening of the case 10, for example, before the lid 11 is attached.

As described above, in this manufacturing method, when joining the lid 11 that seals the case 10, the current collector component, and the electrode body (laminated body 20), a single plate member is used to connect the extraction electrode and the A bundle of negative electrode tab portions is joined together, and then the plate-like member is bent. As a result, in this manufacturing method, the number of bonding steps can be reduced to two while maintaining bonding strength, and manufacturing costs can be suppressed.

For example, in manufacturing the subassembly including the lid 11, in this manufacturing method, not only the positive electrode pole 13 or the take-out electrode connected thereto and the negative pole pole 12 or the take-out electrode connected thereto, but also the positive electrode current collector component 22p and the negative electrode current collector component 22n are also joined together (by caulking, welding, etc.). Thereafter, in this manufacturing method, the subassembly is joined to a bundle of positive electrode and negative electrode tab portions in the positive electrode current collector component 22p and the negative electrode current collector component 22n, respectively. In this manufacturing method, the secondary battery 1 can be manufactured by housing it in the case 10 after such two-step bonding. Further, according to the present manufacturing method, since the housing in the case 10 can be performed after the bonding is completed, the possibility of foreign matter getting into the inside of the case 10 can also be reduced.

In the above example, in order to further prevent foreign matter from entering, the storage process was performed after the positive electrode tab part 21p was joined to the current collector part 22p_3 and the negative electrode tab part 21n was joined to the current collector part 22n_3 in the attachment process.

On the other hand, after the electrode connection part 22p_1 is connected to the positive electrode pole 13 and the electrode connection part 22n_1 is connected to the negative pole pole 12 in the attachment process, the positive electrode tab part 21p and the negative electrode tab part 21p are connected to the current collecting parts 22p_3 and 22n_3, respectively. A storage step can also be performed before joining the tab portion 21n. Even in this case, since the stacked body 20 is only inserted into the case 10 in the state shown in FIG. By arranging the objects, it becomes difficult for foreign objects to enter the inside of the case 10.

Further, in this manufacturing method, the positive electrode current collector component 22p is bent from an L-shape (or an I-shape in the upper row of FIG. 5) to a U-shape as shown in FIG. Therefore, the strength of the connection part 22p_2 is preferably lower than the strength of the current collection part 22p_3 and lower than the strength of the electrode connection part 22p_1. Although only the positive electrode side will be described, the negative electrode side is also similar to the positive electrode side. Note that a plurality of the following examples can be combined as can be seen in the example of FIG.

A configuration example for providing such a strength relationship will be described with the width direction of the positive electrode tab portion 21p as the first direction. For example, as shown in FIG. 5, the width Wb of the connecting portion 22p_2 in the first direction is shorter than the width Wa of the electrode connecting portion 22p_1 in the first direction and the width Wc of the current collecting portion 22p_3 in the first direction. is preferred.

The thickness Db of at least the bent portion of the connecting portion 22p_2 is preferably thinner than the thickness Dc of the current collecting portion 22p_3 and thinner than the thickness Da of the electrode connecting portion 22p_1. In particular, it is preferable that the thin portion of the connecting portion 22p_2 be located on the side that is located on the outside when bent, in terms of ease of forming the parallel clearance Df. In particular, it is preferable in terms of ease of bending that the range Tb in which the plate thickness of the connecting portion 22p_2 on the outside of bending is reduced is larger than the clearance Df.

For example, in FIG. 6, Da = Dc and Db = 0.5 to 0.9 × Da, that is, the connection on the outside of the bending with respect to the plate thickness Da of the electrode connection part 22p_1 and the plate thickness Dc of the current collecting part 22p_3. The plate thickness Db of the portion 22p_2 can be reduced by 10 to 50%. For example, when a laminate 20 having about 73 sets of positive electrode tab portions 21p is employed, the clearance Df can be bent to a constant value of about 0.4 to 1.5 mm.

(alternative example)
Note that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit. For example, the secondary battery includes a lithium ion secondary battery, but is not limited to this, and is not limited to a non-aqueous secondary battery. For example, the shape and material of each member or the manufacturing method described in the above embodiments are not limited to those exemplified, and may function as a secondary battery or such a manufacturing method can be implemented. That's fine.

For example, in FIG. 1 and the like, an example is given in which a rectangular secondary battery is used as the secondary battery 1, but the shape is not limited. Furthermore, although the secondary battery 1 is an example of a secondary battery having an upper tab structure having a tab on the upper side, the present invention is not limited to such an upper tab structure. For example, a secondary battery has a structure in which a stacked body with tabs of both poles pulled out toward one side is housed in a case, and a lid is attached to an opening provided on one side to seal it (hereinafter referred to as horizontal tab structure). ) can also be adopted. Alternatively, the secondary battery can be sealed by storing a laminate in which the tabs of each pole are pulled out toward both sides (both sides or the top and bottom) in a case, and attaching lids to both openings on both sides. It is also possible to adopt a structure (hereinafter referred to as a double-tab structure). A secondary battery having any structure can be manufactured by using the manufacturing method in the embodiment described above. However, in order to increase the capacity of an assembled battery, an upper tab structure in which the tabs are gathered on one side is preferable, and in order to increase the capacity of a secondary battery, an upper tab structure or a horizontal tab structure is more preferable than a double tab structure.

Furthermore, in the above-described embodiments, an example has been described in which a power generating body having a laminated structure is housed in a case, but a wound body (power generating body having a wound body structure) may also be employed as the power generating body. This wound body is, for example, a laminated body in which a separator, a positive electrode sheet, a separator, a negative electrode sheet, and a separator are laminated, and is wound up, and may be formed flat before storage. In this case, the stacking direction of the wound body can be the short axis direction of the wound body, and the lamination direction can be, for example, the direction shown in FIG. 1.

This wound body can also be housed in a case with the end in the direction of the winding axis in the lateral direction, and one or more wound bodies can be housed in the case. Before winding, cut out the active material-uncoated area at predetermined intervals (or at intervals gradually lengthened so that they are at the same position in consideration of winding), and cut out multiple tab parts ( A tab portion for current collection) is formed in advance. By forming the tab portions to have shapes protruding from different ends on the positive electrode side and the negative electrode side, the tab portions of the positive electrode sheets can be bundled at one end (for example, the left end portion) in the wound body. The tab portion of the negative electrode sheet can be bundled at the other end (for example, the right end). The bundled tab portion on the positive electrode side and the bundled tab portion on the negative electrode side may both be led out to the upper side (lid side). In this way, the present embodiment can also be applied to a secondary battery including a stacked body having a wound body structure with a tab portion.

Further, the present invention may be implemented by appropriately combining various examples as described above.

1 Secondary battery 10 Case 11 Lid 11ap, 11an Convex portion 11bp, 11bn Recessed portion 12 Negative electrode pole 13 Positive electrode pole 20 Laminated body 21n Negative electrode tab portion 21p Positive electrode tab portion 22n Negative electrode current collector component 22p Positive electrode current collector component 22p_1 Electrode connection portion 22p_2 Connection part 22p_3 Current collection part 22n_1 Electrode connection part 22n_2 Connection part 22n_3 Current collection part 23 Pedestal 24a, 24b Caulking member 24c, 24d, 24e, 24f Hole 25p, 25n Insulator 26, 26p, 26n Insulator 26b, 26c Hole 26 dp , 26dn recess 26ep, 26en protrusion 26fp, 26fn protrusion 27 release valve 28 liquid inlet

Claims (12)

A plurality of electrode sheets each having an active material region coated with an active material and a tab portion having a shape protruding from the active material region and having a region uncoated with the active material are placed between each electrode sheet. A lamination step of laminating the layers with separators in between to form a laminate;
a storing step of storing the laminate in a case having an opening from the opening;
a sealing step of attaching a lid member to the opening to seal the case;
Equipped with
further comprising an attachment step of joining a bundle of the plurality of tab portions of the electrode sheet having the same polarity to a current collecting component, and attaching the current collecting component to a lid member that closes the opening;
The current collecting component includes a planar current collecting part joined to the bundle of tab parts, and a planar electrode connecting part connected to the take-out electrode on the front surface side of the lid member from the back side of the lid member. a plate-like member having a connecting part connecting between the current collecting part and the electrode connecting part,
In the attaching step, the electrode connecting portion is connected to the take-out electrode, and the bundle of tab portions is joined to the current collecting portion, so that the current collecting portion and the electrode connecting portion are approximately parallel to each other with a gap in between. Bend the connection part so that
The width direction of the tab portion is a first direction,
The width of the current collector in the first direction is longer than the width of the electrode connection part in the first direction,
The attaching step is performed after the bundle of tab parts is joined and before the connecting part is bent, between the current collector part to which the bundle of tab parts is joined after bending and the back surface of the lid member. arranging the insulator so that the insulator is located at and bending the connection part,
A method for manufacturing a secondary battery. The connecting portion is bent so that the current collecting portion and the electrode connecting portion are substantially perpendicular to each other before the attaching step is performed.
A method for manufacturing a secondary battery according to claim 1. After joining the bundle of tab parts to the current collector in the attaching step, performing the storing step;
The method for manufacturing a secondary battery according to claim 1 or 2 . The width of the connecting portion in the first direction is shorter than the width of the electrode connecting portion in the first direction and the width of the current collecting portion in the first direction.
The method for manufacturing a secondary battery according to any one of claims 1 to 3 . The thickness of at least the bent portion of the connecting portion is thinner than the thickness of the current collecting portion and thinner than the thickness of the electrode connecting portion.
The method for manufacturing a secondary battery according to any one of claims 1 to 4 . The current collecting component includes a caulking member having a columnar member passing through a hole provided in the lid member,
In the attaching step, the columnar member is passed through the hole and the caulking member is used to join the columnar member.
The method for manufacturing a secondary battery according to any one of claims 1 to 5 . The laminate is a laminate having a wound structure that is housed in the case in a wound state,
The tab portion of the electrode sheet of one polarity has a shape protruding from one wound end, and the tab portion of the electrode sheet of the other polarity has a shape of protruding from the other wound end. having a shape,
The method for manufacturing a secondary battery according to any one of claims 1 to 6 . A plurality of electrode sheets each having an active material region coated with an active material and a tab portion having a shape protruding from the active material region and having a region uncoated with the active material are placed between each electrode sheet. A laminate made of layers with separators in between,
a current collecting component joined to a bundle of the plurality of tab portions of the electrode sheet having the same polarity;
a case having an opening and accommodating the laminate;
a lid member attached to the opening to seal the case;
Equipped with
The current collecting component includes a planar current collecting part joined to the bundle of tab parts, and a planar electrode connecting part connected to the take-out electrode on the front surface side of the lid member from the back side of the lid member. a plate-like member having a connecting part connecting between the current collecting part and the electrode connecting part,
The strength of the connection part is lower than the strength of the current collector and the strength of the electrode connection part,
the opening portion is sealed by the lid member in a state where the connecting portion is bent so that the current collecting portion and the electrode connecting portion are substantially parallel to each other with a gap in between;
The width direction of the tab portion is a first direction,
The width of the current collector in the first direction is longer than the width of the electrode connection part in the first direction,
an insulator disposed between the current collector part to which the bundle of tab parts is joined and the back surface of the lid member when the connecting part is bent;
Secondary battery. The width of the connecting portion in the first direction is shorter than the width of the electrode connecting portion in the first direction and the width of the current collecting portion in the first direction.
The secondary battery according to claim 8 . The thickness of at least the bent portion of the connecting portion is thinner than the thickness of the current collecting portion and thinner than the thickness of the electrode connecting portion.
The secondary battery according to claim 8 or 9 . The current collecting component has a caulking member,
The caulking member has a columnar member formed in the electrode connection portion and passing through a hole provided in the lid member.
The secondary battery according to any one of claims 8 to 10 . The laminate is a laminate having a wound structure and housed in the case in a wound state,
The tab portion of the electrode sheet of one polarity has a shape protruding from one wound end, and the tab portion of the electrode sheet of the other polarity has a shape of protruding from the other wound end. having a shape,
The secondary battery according to any one of claims 8 to 11 .

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