JP6817143B2 - Laminated battery - Google Patents

Description

The present invention relates to a laminated battery in which an electrode body is covered with a laminated film outer body.

A laminated battery is known in which an electrode body including a positive electrode and a negative electrode is covered with a laminated film outer body, and the outer peripheral side of the laminated film outer body is welded. Such a laminated battery has a positive electrode connection terminal and a negative electrode connection terminal having one end connected to the electrode body inside the laminated film outer body and the other end side extending outward from the laminated film outer body. ..

As described above, the laminated battery in which the electrode body is covered with the laminated film outer body has a shape bulging on one side in the thickness direction of the battery. As such a laminated battery, for example, a laminated battery disclosed in Patent Document 1 is known. As disclosed in Patent Document 1, the electrode tab is bent in the thickness direction inward of the laminated film exterior body.

Further, Patent Document 1 discloses an insulating film sandwiched between a laminated film outer body and an electrode body in a welded portion of the laminated film outer body. Further, in Patent Document 1, the bending portion of the electrode tab is covered with an insulating coating, and the film thickness of the insulating coating covering the bent portion of the insulating coating covers other than the bent portion. A point thinner than the film thickness is disclosed. As a result, the stress generated when the electrode tab is bent can be absorbed by the bent portion, so that it is possible to prevent the current collector from being pulled out when the electrode tab is bent.

Japanese Unexamined Patent Publication No. 2013-30385

In the configuration disclosed in Patent Document 1, the film thickness of the insulating film covering the portion where the bent portion is formed on the electrode tab is thinner than the film thickness of the insulating film covering the other portion, so that the bent portion is formed. A bent portion is more likely to be formed in the formed portion than in the case where a bent portion is formed in the other portion. However, since the insulating coating covers the electrode tabs and is generally hard and difficult to bend, the electrode tabs covered with the insulating coating are difficult to bend.

Further, in the configuration disclosed in Patent Document 1, the insulating coating (resin member) covering the bent portion of the electrode tab (connection terminal) is thinner than the insulating coating covering other portions, so that the bent portion is formed. At that time, the insulating film covering the bent portion may be stretched and thinned. Then, there is a possibility that sufficient electrical insulation cannot be obtained with the insulating film covering the bent portion.

An object of the present invention is that in a laminated battery in which an electrode body is covered with a laminated film outer body, a connection terminal covered with a resin member can be easily provided while ensuring electrical insulation inside the laminated film outer body. The purpose is to realize a structure that can be bent.

The laminated battery according to the embodiment of the present invention has an electrode body including a positive electrode and a negative electrode, a sheet-shaped laminated film outer body in which the outer peripheral side is welded while covering the electrode body, and one end side of the electrode body. The other end is sandwiched between the positive electrode connection terminal and the negative electrode connection terminal extending outward from the laminated film outer body, and the positive electrode connection terminal, the negative electrode connection terminal, and the laminated film outer body, respectively. The positive electrode side resin member and the negative electrode side resin member are provided. At least one of the positive electrode connection terminal and the negative electrode connection terminal has at least one bent portion in a portion located inside the laminated film exterior body. At least one of the positive electrode side resin member and the negative electrode side resin member extends inward of the laminated film exterior body so as to partially cover at least one of the bent portions, and at least one of the bent portions. It has an outer coating and an inner coating that cover the outer and inner sides in the bending direction, respectively. The thickness of the inner coating portion is smaller than the thickness of the outer coating portion (first configuration).

As described above, in at least one of the positive electrode side resin member and the negative electrode side resin member, the thickness of the inner coating portion that covers the inside of the bending portion with respect to at least one of the bending portions covers the outside of the bending direction. By making the thickness smaller than the thickness of the outer coating portion, of the positive electrode connection terminal and the negative electrode connection terminal, the connection terminal covered by the inner coating portion and the outer coating portion can be easily bent.

Further, since the thickness of the outer coating portion is larger than the thickness of the inner coating portion, even if the outer coating portion is stretched when forming at least one of the bending portions, the electrical insulation property of the outer coating portion is obtained. Can be secured.

Further, since the thickness of the inner coating portion is smaller than the thickness of the outer coating portion, the bent state can be maintained at at least one of the bent portions.

Therefore, with the above-described configuration, the connection terminal covered with the resin member can be easily bent while ensuring the electrical insulation inside the laminated film exterior body.

In the first configuration, at least one of the positive electrode connection terminal and the negative electrode connection terminal has a plurality of the bent portions. At least one of the positive electrode side resin member and the negative electrode side resin member covers the bent portion other than the bent portion closest to the electrode body among the plurality of bent portions (second configuration).

When at least one of the positive electrode connection terminal and the negative electrode connection terminal has a plurality of bent portions inside the laminate film exterior body, the bent portions other than the bent portion closest to the electrode body among the plurality of bent portions are on the positive electrode side. By covering with at least one of the resin member and the negative electrode side resin member, the connection terminal covered with the one resin member can be easily bent.

When at least one of the positive electrode connection terminal and the negative electrode connection terminal has a plurality of bent portions inside the laminate film exterior body, the electrode body of the plurality of bent portions may be formed due to a manufacturing dimensional error or the like. It is difficult to cover the nearest bent portion with a resin member extending inward from the welded portion of the laminated film outer body. Therefore, it is preferable to cover the plurality of bent portions other than the bent portion closest to the electrode body with a resin member.

In the first or second configuration, the resin member that covers at least one of the bent portions of the positive electrode side resin member and the negative electrode side resin member constitutes the outer coating portion and the inner coating portion, respectively. Moreover, it has an outer resin member and an inner resin member that are welded while sandwiching the bent portion. The thickness of the inner resin member is smaller than the thickness of the outer resin member (third configuration).

As a result, in at least one of the positive electrode side resin member and the negative electrode side resin member, the thickness of the inner coating portion that covers the inside in the bending direction with respect to at least one of the bending portions becomes the thickness of the outer coating portion that covers the outside in the bending direction. A configuration smaller than the thickness can be realized. Moreover, in the case of the above configuration, the connection terminal can be easily bent regardless of the position inside the laminated film outer body.

In any one of the first to third configurations, the positive electrode connection terminal has at least one bent portion in a portion located inside the laminated film exterior body. The positive electrode side resin member extends inward of the laminated film outer body so as to partially cover at least one of the bent portions, and the outside of the bending direction and the outside of the at least one of the bent portions. It has an outer coating and an inner coating that cover the inside, respectively. The thickness of the inner coating portion of the positive electrode side resin member is smaller than the thickness of the outer coating portion (fourth configuration).

In general, the positive electrode connection terminal of a laminated battery is often made of a material such as aluminum. Therefore, in the positive electrode side resin member that covers the bent portion provided in the positive electrode connection terminal, the thickness of the inner covering portion that covers the inside of the bent portion is made smaller than the thickness of the outer covering portion that covers the outside of the bent portion. As a result, the positive electrode connection terminal can be easily bent.

In any one of the first to fourth configurations, the positive electrode and the negative electrode are strip-shaped electrodes, respectively. The electrode body further has a band-shaped separator arranged between the positive electrode and the negative electrode. It is an electrode body wound with the positive electrode, the negative electrode, and the separator stacked in the thickness direction (fifth configuration).

As described above, in the case of the wound electrode body, the connection terminal often extends from the radial central portion of the electrode body to the outside in the axial direction of the electrode body. Therefore, when the electrode body is covered with the laminated film outer body, the connection terminal has a bent portion inward of the laminated film outer body. Therefore, each of the above configurations is particularly effective in a wound electrode body.

According to the laminated battery according to the embodiment of the present invention, at least one of the positive electrode connection terminal and the negative electrode connection terminal has at least one bent portion inside the laminate film exterior body. At least one of the positive electrode side resin member and the negative electrode side resin member has an outer coating portion that covers the outside in the bending direction and an inner coating portion that covers the inside in the bending direction in at least one of the bending portions. The thickness of the inner coating is smaller than the thickness of the outer coating. As a result, the connection terminal covered with the resin member can be easily bent while ensuring the electrical insulation of the connection terminal inside the laminated film exterior body.

FIG. 1 is a perspective view showing a schematic configuration of a laminated battery according to an embodiment. FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3 is a perspective view showing a schematic configuration of the electrode body. FIG. 4 is a diagram schematically showing a state in which the positive electrode, the negative electrode, and the separator are stacked in the thickness direction. FIG. 5 is a diagram schematically showing how the positive electrode, the negative electrode, and the separator are wound in a state of being overlapped in the thickness direction. FIG. 6 is a diagram schematically showing how the positive electrode connection terminal of the electrode body is deformed in the thickness direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

(overall structure)
FIG. 1 is a perspective view showing a schematic configuration of a laminated battery 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration of the laminated battery 1. The laminated battery 1 is a secondary battery having a rectangular shape in a plan view in which an electrode body 10 functioning as a power generator is covered with a laminated film exterior body 20. In FIG. 2, a part of the electrode body 10 is not shown.

As shown in FIGS. 1 and 2, the laminated battery 1 includes an electrode body 10 and a laminated film exterior body 20 that covers the electrode body 10. Further, the laminated battery 1 includes a positive electrode connection terminal 41 and a negative electrode connection terminal 42 that are electrically connected to the positive electrode 11 and the negative electrode 12 of the electrode body 10, respectively. A non-aqueous electrolytic solution is also sealed inside the laminated battery 1.

The laminated film exterior body 20 is made of a material in which one side of a metal foil made of aluminum is covered with nylon and the other side is covered with polypropylene. That is, the laminated film exterior body 20 is made of a material obtained by laminating aluminum with nylon and polypropylene. As a result, the laminated film outer body 20 is welded by applying pressure while heating the laminated film outer bodies 20 in a state of being overlapped with each other. The metal foil is not limited to aluminum, and may be formed of other metal materials such as stainless steel.

Further, the laminated film exterior body 20 is formed in a substantially rectangular shape. By welding the outer peripheral sides of the laminated film exterior 20 with the electrode body 10 sandwiched between the pair of laminated film exteriors 20, the bulging portion 1a and the sealing portion 1b as shown in FIGS. 1 and 2 are welded to each other. Is formed. That is, the bulging portion 1a is formed by covering the electrode body 10 with the laminated film outer body 20, and the laminated film outer bodies 20 are welded to each other around the bulging portion 1a to seal the bulging portion 1a. Part 1b is formed.

In the present embodiment, the electrode body 10 is a flat electrode body formed by crushing a cylindrical tubular electrode body into a flat shape. That is, the electrode body 10 has a rectangular shape when viewed from the side. Therefore, as shown in FIG. 1, the bulging portion 1a has a rectangular shape in a plan view (hereinafter, also simply referred to as a plan view) of the laminated film exterior body 20. The seal portion 1b is formed around the bulging portion 1a so that the laminated battery 1 has a rectangular shape in a plan view.

Further, in the pair of laminated film exterior bodies 20, as shown in FIG. 2, the laminated battery 1 has a flat surface portion 1c on one side in the thickness direction of the electrode body 10 and the other side in the thickness direction of the electrode body 10. The outer peripheral sides of the laminated film exterior body 20 are welded together with the electrode body 10 sandwiched so as to have the above-mentioned bulging portion 1a. That is, of the pair of laminated film exterior bodies 20, one of the laminated film exterior bodies 20 is arranged so as to follow the outer shape of the electrode body 10.

In the portion of the seal portion 1b located on the end side in the longitudinal direction of the laminated battery 1, the positive electrode connection terminal 41 and the negative electrode connection terminal 42, which will be described later, are sandwiched between the pair of laminated film exterior bodies 20. The laminated film exterior bodies 20 are fixed by welding to each other.

In the present embodiment, the outer peripheral sides of the pair of laminated film outer bodies 20 are welded to each other, but this is not limited to this, and one laminated film outer body is folded back so as to sandwich the electrode body 10 and welded. May be done. The direction in which the laminated film exterior body is folded back may be the stretching direction of the positive electrode connection terminal 41 and the negative electrode connection terminal 42 with respect to the electrode body 10, or may be the width direction.

(Electrode body)
In the following description, the winding axis direction of the electrode body 10 means a direction along the axis L shown in FIG. The radial direction of the electrode body 10 is a direction orthogonal to the winding axis direction.

As shown in FIG. 3, the electrode body 10 is a flat wound electrode body formed in an ellipse when viewed from the winding axis direction. The electrode body 10 is wound after winding the positive electrode 11 and the negative electrode 12 formed in a band shape in a state of being overlapped with each other so that the band-shaped separator 13 is located between the two and under the positive electrode 11, and then pressed. By being crushed, it is formed into a flat shape. The flat electrode body 10 is housed in the space formed by the laminated film exterior body 20.

The state of forming the electrode body 10 is schematically shown in FIGS. 4 and 5. As shown in FIG. 4, the positive electrode 11, the negative electrode 12, and the separator 13 are laminated in the order of the negative electrode 12, the separator 13, the positive electrode 11, and the separator 13 in the thickness direction from the top. In this state, by winding the positive electrode 11, the negative electrode 12, and the separator 13 with a winding core (not shown) in the direction of the white arrow in FIG. 4 (see FIG. 5), a substantially cylindrical tubular electrode body can be obtained.

In FIG. 4, in order to illustrate the state in which the positive electrode 11, the negative electrode 12, and the separator 13 are overlapped with each other, the positions of the positive electrode 11, the negative electrode 12, and the separator 13 are moved from the actual arrangement and shown in perspective. Further, in FIG. 4, in order to distinguish the positive electrode 11, the negative electrode 12, and the separator 13, the positive electrode active material layer 11b of the positive electrode 11 and the negative electrode active material layer 12b of the negative electrode 12 are hatched, although not in cross section.

After obtaining the tubular electrode body as described above, the tubular electrode body is crushed in the radial direction to obtain the flat electrode body 10 as shown in FIG.

The positive electrode 11, the negative electrode 12, and the winding end end of the separator 13 of the electrode body 10 are fixed by the winding stop tape 50. The winding stop tape 50 is made of, for example, PP (polypropylene) or the like.

As shown in FIG. 4, the positive electrode 11 contains a positive electrode current collector 11a made of a metal foil such as aluminum and a positive electrode active material layer 11b containing a positive electrode active material and provided on both sides of the positive electrode current collector 11a, respectively. Has. Specifically, the positive electrode 11 is a positive electrode mixture containing a positive electrode active material, a conductive auxiliary agent, a binder, etc., which is a lithium-containing oxide capable of occluding and releasing lithium ions, on a positive electrode current collector 11a made of aluminum foil or the like. It is formed by applying and drying. As the lithium-containing oxide as the positive electrode active material, for example, a lithium cobalt oxide such as LiCoO ₂ , a lithium manganese oxide such as LiMn ₂ O _4, and a lithium composite oxide such as a lithium nickel oxide such as LiNiO ₂ are used. Is preferable. As the positive electrode active material, only one kind of substance may be used, or two or more kinds of substances may be used. Further, the positive electrode active material is not limited to the above-mentioned substances.

The positive electrode 11 has positive electrode current collector exposed portions 11c and 11d which are not provided with positive electrode active material layers 11b on both sides at both ends in the longitudinal direction of the positive electrode current collector 11a. That is, the positive electrode current collector exposed portion 11c is located on one side of the positive electrode 11 in the longitudinal direction, and the positive electrode current collector exposed portion 11d is located on the other side of the positive electrode 11 in the longitudinal direction. In the electrode body 10 of the present embodiment, the positive electrode current collector exposed portion 11c is located on the winding start side (inside of the electrode body 10) of the electrode body 10, and the positive electrode current collector exposed portion 11d is the winding of the electrode body 10. It is located on the end side (the outermost peripheral side of the electrode body 10).

The negative electrode 12 has a negative electrode current collector 12a made of a metal foil such as copper, and a negative electrode active material layer 12b containing a negative electrode active material and provided on both sides of the negative electrode current collector 12a, respectively. Specifically, the negative electrode 12 is dried by applying a negative electrode mixture containing a negative electrode active material capable of occluding and releasing lithium ions, a conductive auxiliary agent, a binder, and the like onto a negative electrode current collector 12a made of copper foil or the like. Formed by. As the negative electrode active material, for example, it is preferable to use a carbon material (graphites, pyrolytic carbons, cokes, glassy carbons, etc.) capable of occluding and releasing lithium ions. The negative electrode active material is not limited to the above-mentioned substances.

Like the positive electrode 11, the negative electrode 12 also has negative electrode current collector exposed portions 12c and 12d on both ends of the negative electrode current collector 12a in the longitudinal direction in which the negative electrode active material layers 12b are not provided on both sides. That is, the negative electrode current collector exposed portion 12c is located on one side of the negative electrode 12 in the longitudinal direction, and the negative electrode current collector exposed portion 12d is located on the other side of the negative electrode 12 in the longitudinal direction. In the electrode body 10 of the present embodiment, the negative electrode current collector exposed portion 12c is located on the winding start side (inside of the electrode body 10) of the electrode body 10, and the negative electrode current collector exposed portion 12d is the winding of the electrode body 10. It is located on the end side (the outermost peripheral side of the electrode body 10).

The positive electrode connection terminal 41 is connected to the positive electrode current collector exposed portion 11c located on the winding start side of the electrode body 10 in the positive electrode 11. The negative electrode connection terminal 42 is connected to the negative electrode current collector exposed portion 12c located on the winding start side of the electrode body 10 in the negative electrode 12. The positive electrode connection terminal 41 and the negative electrode connection terminal 42 are drawn out to the outside of the electrode body 10 and to the outside of the laminated film exterior body 20.

The positive electrode connection terminal 41 is made of an aluminum metal foil formed in a rectangular shape in a plan view. One side of the positive electrode connection terminal 41 in the longitudinal direction is connected to the exposed portion 11c of the positive electrode current collector of the positive electrode 11 by welding, and the other side in the longitudinal direction is located outside the laminated film exterior body 20 (FIG. 1). And FIG. 2). That is, the positive electrode connection terminal 41 is sandwiched by the laminated film outer body 20, and extends from the inside to the outside of the laminated film outer body 20.

The negative electrode connection terminal 42 is made of a metal foil such as copper or nickel formed in a rectangular shape in a plan view. One side of the negative electrode connection terminal 42 in the longitudinal direction is connected to the exposed portion 12c of the negative electrode current collector by welding, and the other side in the longitudinal direction is located outside the laminated film exterior body 20. That is, the negative electrode connection terminal 42 is sandwiched by the laminate film exterior body 20, and extends from the inside to the outside of the laminate film exterior body 20.

By using the positive electrode connection terminal 41 and the negative electrode connection terminal 42 having the above-described configuration in the laminated battery 1, the impedance can be reduced as compared with the configuration in which the connection terminal is pulled out to the outside via other connection components. it can.

After the electrode body 10 is formed, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are partially bent in the longitudinal direction in the thickness direction as shown in FIG. Therefore, as shown in FIG. 2, in a state where the electrode body 10 is covered with the laminated film outer body 20, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are respectively located inward of the laminated film outer body 20 in the thickness direction. It has bent portions 43 and 44 bent in a straight line. Since the positive electrode connection terminal 41 and the negative electrode connection terminal 42 have the same shape, only the positive electrode connection terminal 41 is shown in FIGS. 2 and 6, and only the reference numerals are shown for the configuration related to the negative electrode connection terminal 42.

In the present embodiment, the bent portions 43 and 44 have a first bent portion 43a and 44a close to the electrode body 10 and a second bent portion 43b and 44b close to the welded portion of the laminated film exterior body 20, respectively. That is, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 have two bent portions 43a, 43b, 44a, 44b, respectively.

The first bent portions 43a and 44a are bent outward in the radial direction of the electrode body 10. The second bent portions 43b and 44b are bent outward in the winding axis direction of the electrode body 10. As described above, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 have the first bent portions 43a and 44a and the second bent portions 43b and 44b, respectively, so that one end side of the electrode body 10 is as shown in FIG. The positive electrode connection terminal 41 and the negative electrode connection terminal 42 connected to the inside (inner peripheral side in the radial direction) extend in the winding axis direction on the radial outer side of the electrode body 10.

As a result, in the laminated battery 1 having the bulging portion 1a and the flat surface portion 1c, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 can be extended from the flat surface portion 11c side to the outside of the laminated film exterior body 20. .. Therefore, the outer peripheral side of the laminated film exterior body 20 can be more reliably welded while the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are more reliably sandwiched by the laminated film exterior body 20. Therefore, in the laminated battery 1, the sealing property of the laminated film exterior body 20 can be improved.

As shown in FIGS. 1 and 2, on the surfaces of the positive electrode connection terminal 41 and the negative electrode connection terminal 42, the positive electrode side resin member 45 and the negative electrode side resin member 46 are respectively sandwiched by the laminate film exterior body 20. It is provided. That is, the positive electrode side resin member 45 is located between the laminated film exterior body 20 and the positive electrode connection terminal 41, and the negative electrode side resin member 46 is located between the laminated film exterior body 20 and the negative electrode connection terminal 42.

As a result, the welding strength of the laminated film outer body 20 and the positive electrode connection terminal 41 and the negative electrode connection terminal 42 sandwiched between the laminated film outer body 20 can be improved, and the positive electrode connection terminal 41 and the negative electrode connection terminal 42 The laminated film exterior body 20 can be more reliably and electrically insulated.

The positive electrode side resin member 45 and the negative electrode side resin member 46 are each composed of sheet-shaped outer resin members 47b, 48b and inner resin members 47a, 48a, which are made of a resin material such as polypropylene (PP) and are rectangular in a plan view. ing. That is, the positive electrode side resin member 45 has an outer resin member 47b and an inner resin member 47a. The negative electrode side resin member 46 has an outer resin member 48b and an inner resin member 48a. In the present embodiment, the thicknesses of the inner resin members 47a and 48a are smaller than the thicknesses of the outer resin members 47b and 48b, respectively. For example, the thickness of the inner resin members 47a and 48a is 0.08 mm, and the thickness of the outer resin members 47b and 48b is 0.1 mm.

The positive electrode side resin member 45 is formed by depositing the outer resin member 47b and the inner resin member 47a on the surface of the positive electrode connection terminal 41 in a state where the positive electrode connection terminal 41 is sandwiched between them. Further, the negative electrode side resin member 46 is formed by depositing the outer resin member 48b and the inner resin member 48a on the surface of the negative electrode connection terminal 42 in a state where the negative electrode connection terminal 42 is sandwiched between them.

The positive electrode side resin member 45 and the negative electrode side resin member 46 are bent portions 43 and 44 other than the first bent portions 43a and 44a closest to the electrode body 10, that is, the second of the positive electrode connection terminal 41 and the negative electrode connection terminal 42, respectively. It is provided so as to cover the bent portions 43b and 44b. Specifically, the outer resin member 47b and the inner resin member 47a are arranged so as to sandwich the second bent portion 43b of the positive electrode connection terminal 41 in the thickness direction. The outer resin member 48b and the inner resin member 48a are arranged so as to sandwich the second bent portion 44b of the negative electrode connection terminal 42 in the thickness direction.

The inner resin members 47a and 48a, which are smaller in thickness than the outer resin members 47b and 48b, are arranged on the inner surface of the second bending portions 43b and 44b in the bending direction. Therefore, in the inner resin members 47a and 48a, the portions located on the inner surface of the second bent portions 43b and 44b in the bending direction are the inner covering portions 45a and 46a. Further, in the outer resin members 47b and 48b, the portions located on the outer surface of the second bent portions 43b and 44b in the bending direction are the outer covering portions 45b and 46b.

The bending direction means the direction in which the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are bent. Further, the inside in the bending direction means a portion located inside in the positive electrode connection terminal 41 and the negative electrode connection terminal 42 when the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are bent. The outside in the bending direction means a portion of the positive electrode connection terminal 41 and the negative electrode connection terminal 42 that is located outside when the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are bent.

With the above configuration, since the positive electrode side resin member 45 and the negative electrode side resin member 46 are located inside the laminated film exterior body 20, the electrode body 10 and the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are more reliably electrically connected. Can be insulated.

Moreover, when the second bent portions 43b and 44b are formed on the positive electrode connection terminal 41 and the negative electrode connection terminal 42 covered by the positive electrode side resin member 45 and the negative electrode side resin member 46, respectively, the positive electrode connection terminal 41 and the negative electrode connection terminal The 42 can be easily bent.

Further, in the present embodiment, the outer resin members 47b, 48b, which are thicker than the inner resin members 47a, 48a, are outside the second bending portions 43b, 44b of the positive electrode connection terminal 41 and the negative electrode connection terminal 42 in the bending direction. It is positioned. As a result, even when the outer resin members 47b and 48b are pulled and stretched outside in the bending direction of the second bent portions 43b and 44b, the thickness required for ensuring the electrical insulation of the outer resin members 47b and 48b is increased. Can be secured. Further, the outer side of the second bending portions 43b and 44b of the positive electrode connection terminal 41 and the negative electrode connection terminal 42 in the bending direction is relatively close to the electrode body 10, but the outer resin members 47b and 48b make the electrode bodies 10 and the first. 2 The bent portions 43b and 44b can be more reliably electrically insulated. Further, by making the thickness of the inner resin members 47a and 48a smaller than the thickness of the outer resin members 47b and 48b, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are bent at the second bent portions 43b and 44b. It can be held securely.

A protective film 55 (protective member) is attached to both sides of the positive electrode current collector exposed portion 11c of the positive electrode 11 to which the positive electrode connection terminal 41 is connected. The protective film 55 projects outward from the positive electrode current collector exposed portion 11c in the lateral direction of the positive electrode 11. That is, the width of the protective film 55 in the lateral direction is larger than the width of the positive electrode current collector exposed portion 11c in the lateral direction. In the present embodiment, the protective film 55 covers from the positive electrode current collector exposed portion 11c side to the end portion of the positive electrode side resin member 45 in the positive electrode connection terminal 41. The protective film 55 is made of, for example, PP (polypropylene) or the like.

By attaching the protective film 55 to the positive electrode current collector exposed portion 11c in this way, a short circuit occurs between the positive electrode current collector exposed portion 11c of the positive electrode 11 and the negative electrode current collector exposed portion 12c of the negative electrode 12. Can be prevented.

At least one of the protective films 55 attached to both sides of the positive electrode current collector exposed portion 11c is colored (for example, blue). This makes it possible to easily confirm whether or not the protective film 55 is attached to the exposed portion 11c of the positive electrode current collector.

The separator 13 has a resin porous layer. As the separator 13, a microporous film made of polyolefin used in an electrochemical element such as a conventionally known lithium secondary battery can be used.

(Manufacturing method of laminated battery)
Next, a method of manufacturing the laminated battery 1 having the above-described configuration will be described with reference to FIGS. 4 to 6.

First, a band-shaped positive electrode 11 and a negative electrode 12 are formed. Although detailed description will be omitted, each of the positive electrode 11 and the negative electrode 12 forms the positive electrode active material layer 11b and the negative electrode active material layer 12b in a predetermined range on the metal foil, and then the positive electrode active material layer 11b and the negative electrode active material layer 12b, respectively. It is obtained by welding the positive electrode connection terminal 41 and the negative electrode connection terminal 42 to the positive electrode current collector exposed portion 11c and the negative electrode current collector exposed portion 12c, which are not provided with the above, respectively.

The positive electrode connection terminal 41 and the negative electrode connection terminal 42 are provided with a positive electrode side resin member 45 and a negative electrode side resin member 46 in advance, respectively. Further, after the positive electrode connection terminal 41 is attached to the positive electrode current collector exposed portion 11c, the protective film 55 is attached to a part of the positive electrode current collector exposed portion 11c and the positive electrode connection terminal 41.

As shown in FIG. 4, the positive electrode 11 and the negative electrode 12 obtained as described above are wound around the separator 13 in a state of being overlapped with each other in the thickness direction to obtain a cylindrical tubular electrode body. When winding the positive electrode 11, the negative electrode 12, and the separator 13, the positive electrode 11, the negative electrode 12, and the separator 13 are wound so as to be wound around a core (not shown) (see FIG. 5).

In the present embodiment, the positive electrode 11, the negative electrode 12, and the separator 13 are stacked in the order of the separator 13, the positive electrode 11, the separator 13, and the negative electrode 12 from the bottom. When winding the positive electrode 11, the negative electrode 12, and the separator 13, the positive electrode 11, the negative electrode 12, and the separator 13 are wound while applying a predetermined tension to them.

As shown in FIG. 5, in the tubular electrode body, the positive electrode connection terminal 41 connected to the positive electrode 11 and the negative electrode connection terminal 42 connected to the negative electrode 12 are outward from the inner peripheral side of the tubular electrode body in the winding axis direction. It protrudes toward. Therefore, the positive electrode side resin member 45 provided on the positive electrode connection terminal 41 and the negative electrode side resin member 46 provided on the negative electrode connection terminal 42 are also exposed to the outside of the tubular electrode body.

The winding end end of the tubular electrode body obtained by winding the positive electrode 11, the negative electrode 12, and the separator 13 as described above is fixed by the winding stop tape 50.

After that, the tubular electrode body is sandwiched by a pressing device (not shown) and formed into a flat shape. As a result, the electrode body 10 is obtained.

As shown in FIG. 6, a part of the positive electrode connection terminal 41 and the negative electrode connection terminal 42 in the longitudinal direction of the obtained electrode body 10 is pressed in the thickness direction. As a result, the first bent portions 43a and 44a and the second bent portions 43b and 44b are formed on the positive electrode connection terminal 41 and the negative electrode connection terminal 42.

The second bent portions 43b and 44b are formed in the portions of the positive electrode connection terminal 41 and the negative electrode connection terminal 42 that are covered by the positive electrode side resin member 45 and the negative electrode side resin member 46. Further, in the second bent portions 43b and 44b, of the resin members 47a, 47b, 48a and 48b constituting the positive electrode side resin member 45 and the negative electrode side resin member 46, the inner resin members 47a and 48a having a smaller thickness are bent, respectively. It is formed so as to be located inside the direction.

As a result, the second bent portions 43b and 44b can be easily formed without the positive electrode side resin member 45 and the negative electrode side resin member 46 interfering with the bending deformation of the positive electrode connecting terminal 41 and the negative electrode connecting terminal 42.

After that, with the electrode body 10 placed on the laminate film exterior body 20, another laminate film exterior body 20 is overlapped, and two laminate film exterior bodies 20 are welded around the electrode body 10. As a result, as shown in FIG. 1, the seal portion 1b is formed so as to surround the electrode body 10. When the seal portion 1b is formed, the positive electrode side resin member 45 of the positive electrode connection terminal 41 connected to the electrode body 10 and the negative electrode side resin member 46 of the negative electrode connection terminal 42 are also two laminated film exterior bodies 20. Welding while sandwiched between.

As described above, when the electrode body 10 is covered with the two laminated film outer bodies 20, the two laminated film outer bodies 20 are covered with the electrode body so that the flat surface portion 1c is formed by one of the laminated film outer bodies 20. Arrange for 10. That is, of the two laminated film exterior bodies 20, one of the laminated film exterior bodies 20 constitutes a flat surface portion 1c, and the other laminated film exterior body 20 constitutes a bulging portion 1a.

When the electrode body 10 is covered with one laminated film outer body, the laminated film outer body is folded back on the side opposite to the positive electrode connection terminal 41 and the negative electrode connection terminal 42 of the electrode body 10, and the electrode body is covered with the laminated film outer body. The outer peripheral sides of the laminated film outer body may be welded together with the 10 sandwiched between them. In this case, since the configuration is the same as described above except that the electrode body is covered with one laminated film outer body, detailed description thereof will be omitted.

From the above, in the present embodiment, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 have bent portions 43 and 44 in the portions located inside the laminated film exterior body 20. The positive electrode side resin member 45 and the negative electrode side resin member 46 sandwiched between the positive electrode connection terminal 41 and the negative electrode connection terminal 42 and the laminate film exterior body 20 extend inward of the laminate film exterior body 20, respectively. The outer covering portions 45b and 46b and the inner covering portions 45a and 46a cover the outer and inner sides of the second bending portions 43b and 44b in the bending direction, respectively, among the bending portions 43 and 44. The thickness of the inner covering portions 45a and 46a is smaller than the thickness of the outer covering portions 45b and 46b.

As a result, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 can be easily bent.

Further, in the positive electrode side resin member 45 and the negative electrode side resin member 46, the thickness of the inner covering portions 45a and 46a covering the inside of the second bending portions 43b and 44b in the bending direction is smaller than the thickness of the outer covering portions 45b and 46b. Therefore, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 can be maintained in a bent state at the second bent portions 43b and 44b.

Moreover, since the thickness of the outer covering portions 45b and 46b is larger than the thickness of the inner covering portions 45a and 46a, even if the outer covering portions 45b and 46b extend outside the second bent portions 43b and 44b, the outer covering portions 45b and 46b The electrical insulation of 45b and 46b can be ensured.

Therefore, according to the configuration of the present embodiment, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 connected to the electrode body 10 can be easily bent while ensuring the electrical insulation inside the laminated film exterior body 20.

Further, in the present embodiment, the positive electrode side resin member 45 and the negative electrode side resin member 46 cover the bent portions 43, 44 other than the bent portion closest to the electrode body 10, that is, the second bent portions 43b, 44b. As a result, in the positive electrode connection terminal 41 and the negative electrode connection terminal 42, the portions covered by the positive electrode side resin member 45 and the negative electrode side resin member 46 can be easily bent, and the positive electrode side resin member 45 and the negative electrode side can be easily bent. It is possible to secure the electrical insulation of the positive electrode side resin member 45 and the negative electrode side resin member located outside the bending direction in the bent portion covered by the resin member 46.

Due to a manufacturing dimensional error of the electrode body 10 or the like, the bent portion closest to the electrode body 10 among the plurality of bent portions is extended from the welded portion of the laminate film exterior body 20 to the inside of the laminate film exterior body 20. It is difficult to cover with the positive electrode side resin member 45 and the negative electrode side resin member 46. Therefore, it is preferable to cover the bent portion closest to the electrode body 10 among the plurality of bent portions with the protective film 55.

Further, in the present embodiment, in the positive electrode side resin member 45 and the negative electrode side resin member 46, the thickness of the inner resin members 47a and 48a is smaller than the thickness of the outer resin members 47b and 48b. As a result, as described above, it is possible to realize a configuration in which the thickness of the inner covering portions 45a and 46a is smaller than the thickness of the outer covering portions 45b and 46b.

The configuration of the present embodiment is intended for an electrode body 10 obtained by winding a strip-shaped positive electrode 11, a negative electrode 12, and a separator 13 in a state of being stacked in the thickness direction, respectively. In the case of such a wound type electrode body 10, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are often connected to the inner peripheral side in the radial direction of the electrode body 10. Further, in the case of the laminated battery 1, since the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are pulled out from the flat surface portion 1c side, they are bent in the radial direction of the electrode body 10 inside the laminated film exterior body 20. ..

As described above, it is particularly effective to apply the configuration of the present embodiment to the laminated battery 1 having the winding type electrode body 10 in which the positive electrode connection terminal 41 and the negative electrode connection terminal 42 are bent in the radial direction. ..

(Other embodiments)
Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the embodiment is not limited to the above-described embodiment, and the above-described embodiment can be appropriately modified and implemented within a range that does not deviate from the gist thereof.

In the above embodiment, the positive electrode side resin member 45 and the negative electrode side resin member 46 are formed by the inner resin members 47a and 48a and the outer resin members 47b and 48b arranged so as to sandwich the positive electrode connection terminal 41 and the negative electrode connection terminal 42, respectively. It is configured. Moreover, with the positive electrode connection terminal 41 and the negative electrode connection terminal 42 provided with the positive electrode side resin member 45 and the negative electrode side resin member 46 attached to the positive electrode and the negative electrode 12, respectively, the positive electrode 11 and the negative electrode 12 are attached together with the separator 13. By winding, the electrode body 10 is formed.

However, the positive electrode side resin member and the negative electrode side resin member may be attached to the positive electrode connection terminal and the negative electrode connection terminal, respectively, after forming the wound body. For example, the positive electrode side resin member and the negative electrode side resin member may be formed in an annular shape to form a wound body, and then the mounting positions with respect to the positive electrode connection terminal and the negative electrode connection terminal may be adjusted and fixed.

In the above embodiment, the electrode body 10 is a flat electrode body formed by crushing a cylindrical tubular electrode body into a flat shape. However, the electrode body may be a flat electrode body formed in a flat shape by using a rhombus or a flat plate winding core without crushing the electrode body in a flat shape.

In the embodiment, the configuration of the embodiment is applied to the electrode body 10 obtained by winding the strip-shaped positive electrode 11, the negative electrode 12, and the separator 13 in a state of being stacked in the thickness direction, respectively. However, the configuration of the above embodiment may be applied to a laminated electrode body obtained by stacking a sheet-shaped positive electrode, a negative electrode, and a separator in the thickness direction, respectively.

In the above embodiment, the positive electrode side resin member 45 and the negative electrode side resin member 46 provided on the positive electrode connection terminal 41 and the negative electrode connection terminal 42, respectively, are formed in the positive electrode connection terminal 41 and the negative electrode connection terminal 42, respectively. , 44b is covered. However, only one of the positive electrode side resin member and the negative electrode side resin member may cover the second bent portion.

In the above embodiment, the positive electrode side resin member 45 and the negative electrode side resin member 46 are inner resin members 47a located inside the second bending portions 43b and 44b formed in the positive electrode connection terminal 41 and the negative electrode connection terminal 42 in the bending direction. , 48a is smaller than the thickness of the outer resin members 47b, 48b located outside in the bending direction. However, in one of the positive electrode side resin member and the negative electrode side resin member, the thickness of the inner resin member located inside the bending direction of the second bending portion is smaller than the thickness of the outer resin member located outside the bending direction. You may. Since the positive electrode connection terminal is made of, for example, an aluminum metal foil, it is difficult to form a bent portion in the positive electrode connection terminal. Therefore, in the positive electrode side resin member covering the second bent portion of the positive electrode connection terminal, the thickness of the inner resin member located inside the bending direction of the second bent portion is set to the outer resin member located outside the bending direction. It is preferable that the thickness is smaller than the thickness of.

In the above embodiment, the positive electrode side resin member 45 and the negative electrode side resin member 46 cover the second bent portions 43b and 44b formed on the positive electrode connection terminal 41 and the negative electrode connection terminal 42. However, the positive electrode side resin member and the negative electrode side resin member may cover the first bent portion and the second bent portion formed on the positive electrode connecting terminal and the negative electrode connecting terminal.

In the above embodiment, the positive electrode connection terminal 41 and the negative electrode connection terminal 42 have first bending portions 43a and 44a and second bending portions 43b and 44b, respectively. However, the positive electrode connection terminal and the negative electrode connection terminal may each have three or more bent portions. Further, only one of the positive electrode connection terminal and the negative electrode connection terminal may have a plurality of bent portions.

In the above embodiment, the positive electrode side resin member 45 and the negative electrode side resin member 46 are separate members. However, the positive electrode side resin member and the negative electrode side resin member may be integrated.

In the above embodiment, a part of the positive electrode connection terminal 41 is covered with the protective film 55. However, a part of the positive electrode connection terminal may not be covered with the protective film. Further, a part of the negative electrode connection terminal 42 may be covered with a protective film.

In the above embodiment, the positive electrode 11 and the negative electrode 12 formed in a band shape are superposed on the separator 13 so that the separator 13 is located between them and below the positive electrode 11, respectively. However, the order in which the positive electrode 11, the negative electrode 12, and the separator 13 are stacked may be any order as long as the secondary battery can be constructed.

In the above embodiment, the laminated battery is formed in a rectangular shape in a plan view. However, the laminated battery may have other shapes such as a polygonal shape.

In the above embodiment, the laminated battery 1 is a lithium ion battery. However, the laminated battery 1 may be a battery other than the lithium ion battery.

INDUSTRIAL APPLICABILITY The present invention can be used for a laminated battery in which an electrode body formed in a flat shape is covered with a laminated film outer body after winding a positive electrode, a negative electrode and a separator.

1 Laminated battery 10 Electrode body 11 Positive electrode 12 Negative electrode 13 Separator 20 Laminate film exterior body 41 Positive electrode connection terminal 42 Negative electrode connection terminal 43, 44 Bent portions 43a, 44a First bent portion 43b, 44b Second bent portion 45 45a, 46a Inner coating 45b, 46b Outer coating 46 Negative electrode side resin member 47a, 48a Inner resin member 47b, 48b Outer resin member 55 Protective film (protective member)

Claims (5)

An electrode body including a positive electrode and a negative electrode,
A sheet-shaped laminated film outer body in which the outer peripheral side is welded while covering the electrode body, and
One end side is connected to the electrode body, and the other end side is a positive electrode connection terminal and a negative electrode connection terminal extending outward from the laminated film outer body.
The positive electrode side resin member and the negative electrode side resin member sandwiched between the positive electrode connection terminal and the negative electrode connection terminal and the laminated film exterior body, respectively,
With
At least one of the positive electrode connection terminal and the negative electrode connection terminal has at least one bent portion in a portion located inside the laminated film outer body.
At least one of the positive electrode side resin member and the negative electrode side resin member extends inward of the laminated film outer body so as to partially cover at least one of the bent portions, and at least one of the bent portions. It has an outer coating and an inner coating that cover the outer and inner sides of the bending direction, respectively.
A laminated battery in which the thickness of the inner coating portion is smaller than the thickness of the outer coating portion. In the laminated battery according to claim 1,
At least one of the positive electrode connection terminal and the negative electrode connection terminal has a plurality of the bent portions.
A laminated battery in which at least one of the positive electrode side resin member and the negative electrode side resin member covers a portion other than the bent portion closest to the electrode body among the plurality of bent portions. In the laminated battery according to claim 1 or 2.
Of the positive electrode side resin member and the negative electrode side resin member, the resin member that covers at least one of the bent portions constitutes the outer coating portion and the inner coating portion, respectively, and sandwiches the bent portion. It has an outer resin member and an inner resin member that are welded,
A laminated battery in which the thickness of the inner resin member is smaller than the thickness of the outer resin member. In the laminated battery according to any one of claims 1 to 3.
The positive electrode connection terminal has at least one bent portion in a portion located inside the laminated film outer body.
The positive electrode side resin member extends inward of the laminated film outer body so as to partially cover at least one of the bent portions, and extends outward in the bending direction with respect to at least one of the bent portions. It has an outer coating and an inner coating that cover the inside, respectively.
A laminated battery in which the thickness of the inner coating portion of the positive electrode side resin member is smaller than the thickness of the outer coating portion. In the laminated battery according to any one of claims 1 to 4.
The positive electrode and the negative electrode are strip-shaped electrodes, respectively.
The electrode body is
Further having a strip-shaped separator arranged between the positive electrode and the negative electrode,
A laminated battery, which is an electrode body in which the positive electrode, the negative electrode, and the separator are wound in a state of being stacked in the thickness direction.

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