JP2009016188A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery with high reliability having a large passage area of current secured at current collection. <P>SOLUTION: The battery 100 is provided with a wound-around electrode body 20 and current collection members 10a, 10b jointed to the wound-around electrode body 20. Current collection foil laminated portions 22a, 22b which are jointed to the current collection members 10a, 10b are formed at the end part in winding axis direction of the wound-around electrode body 20, and the current collection foil laminated portions 22a, 22b have inclined faces 24a, 24b inclined to the winding axis direction. The current collection members 10a, 10b have current collection faces 14a, 14b inclined opposed to the inclined faces 24a, 24b, and the current collection foil laminated portions 22a, 22b and the current collection members 10a, 10b are jointed with a conductive jointing member 40 interposed between the inclined faces 24a, 24b and the current collection faces 14a, 14b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a battery including a wound electrode body having a spiral structure. In detail, it is related with the junction structure of the said winding electrode body and a current collection member.

  Among various types of batteries, there is a battery (hereinafter also referred to as “winding battery”) including an electrode body (winding electrode body) having a spiral structure. By making the electrode body have a spiral structure, the reaction area of the positive and negative electrodes can be increased, thereby increasing the energy density and enabling high output. A battery equipped with such a wound electrode body is becoming increasingly important as a power source for mounting on a vehicle as a power source for obtaining a high output, or a power source for a personal computer and a portable seat terminal.

One of current collecting methods for a battery provided with this type of wound electrode body is a tab-type current collection. In the tab type current collection, as shown in FIG. 6, the side edges of the long sheet-like electrode body 200 are exposed without adhering the active material, and a plurality of current collection tabs 202 are formed on the exposed portion (active material uncoated portion 201). Join. Next, as shown in FIG. 7, the sheet electrode body 200 is wound to form a wound electrode body 203, and the wound electrode bodies 203 are bundled together via the current collecting tab 202 and connected to the current collecting member. . As another conventional technique, Patent Document 2 can be cited.
JP 2000-235853 A JP 2001-93579 A

  However, in the above-described current collecting method using the tab-type current collector, when the wound electrode body is bundled through the current collecting tab, wrinkles and slack are generated in the wound electrode body (particularly at the joint portion with the current collecting tab). There is a fear. If wrinkles or slack occurs in the electrode body, the active material peels off from the electrode body and the battery performance deteriorates, or the current density becomes uneven due to gaps caused by wrinkles (particularly in places where the current density is high, the temperature increases). The separator may dissolve), which is not preferable.

  Moreover, in the current collection method using the tab type current collection, the joint area between the current collection tab and the active material uncoated portion is in line contact, so the contact area (current channel area) is relatively small, The electrical resistance increases. If the electrical resistance at the time of current collection is increased, heat loss due to heat generation is increased, and there is a concern that the battery performance may be lowered.

  The present invention has been made in view of such a point, and a main object of the present invention is to provide a highly reliable wound battery while ensuring a large current passage area during current collection. .

  A battery provided by the present invention is joined to a wound electrode body formed by winding a sheet-like electrode body including a foil-like current collector and a separator, and an end surface in the winding axis direction of the wound electrode body. A current collecting member. At the end in the winding axis direction of the wound electrode body, a current collector foil laminated portion joined to the current collector is formed. This current collector foil laminated portion has an inclined surface which is a surface bonded to the current collector and is inclined with respect to the winding axis direction. Moreover, the said current collection member has a current collection surface which is a surface joined to the said current collection foil lamination | stacking part, and inclines facing the said inclined surface. And the said current collection foil laminated | stacked part and the said current collection member are joined in the state which interposed the electroconductive joining member between the said inclined surface and the said current collection surface, It is characterized by the above-mentioned.

  According to the configuration of the present invention, since the current collecting foil laminated portion of the wound electrode body and the current collecting member are joined to each other, the end portion (current collecting foil laminated portion) of the wound electrode body is There is no need to bundle them together, and it is possible to avoid wrinkles and slack in the wound electrode body. Thereby, the bad influence (for example, peeling of an active material or non-uniform | heterogenous current density) which the wrinkles and slack which arose in the winding electrode body have on battery performance can be prevented beforehand. Therefore, according to the configuration of the present invention, a highly reliable battery can be provided.

  Further, since the inclined surface and the current collecting surface are brought into surface contact by interposing the conductive bonding member, the contact area between the current collector foil laminated portion of the wound electrode body and the current collecting member can be increased. In addition, since the surfaces inclined with respect to the winding axis direction (inclined surface and current collecting surface) are joined, the contact area between the two becomes larger. As a result, it is possible to improve the bonding strength between the current collector foil laminated portion of the wound electrode body and the current collecting member, and to increase the flow area of the current derived from the wound electrode body to the current collecting member. Can do. As a result, current collection resistance is reduced, heat loss is reduced, and current collection efficiency is improved.

  The inclined surface is preferably an inverted conical concave surface, and the current collecting surface is preferably a conical convex surface. According to this configuration, the convex surface of the current collecting member can be fitted into the concave surface of the current collector foil laminated portion of the wound electrode body, and the strength of the wound electrode body can be reinforced.

  In a preferred embodiment of the battery disclosed herein, the sheet-like electrode has a sheet-like protruding portion that protrudes from the separator. The planar shape of the sheet-shaped electrode including the protruding portion in a developed state is a trapezoidal shape or a triangular shape. The current collector foil laminated portion is formed by winding the sheet-like protruding portion. At this time, the inclined surface of the current collector foil laminated portion is formed by a side edge portion of the sheet-like protruding portion in a wound state. According to this configuration, the inclined surface of the current collector foil laminated portion can be easily produced.

  In a preferred aspect of the battery disclosed herein, the current collecting surface of the current collecting member is formed in a step shape so as to correspond to the side edge portion of the sheet-like protruding portion in the wound state. And the said inclined surface and the said current collection surface are joined in the surface contact state via the said electroconductive joining member, It is characterized by the above-mentioned. According to this configuration, the inclined surface and the current collecting surface can be reliably brought into surface contact, and the bonding strength can be further increased.

  In a preferred aspect of the battery disclosed herein, the conductive bonding member is attached to a side edge portion of the sheet-like protruding portion. In this configuration, the conductive bonding member can be easily supplied between the inclined surface and the current collecting surface.

  In a preferred aspect of the battery disclosed herein, an outer case that houses the wound electrode body is provided. The opening of the exterior case is blocked by the current collecting member. Thereby, the current collecting member and the lid of the battery case can be used together, and the number of parts of the battery can be reduced.

  In a preferred aspect of the battery disclosed herein, a core material locked to the current collecting member is disposed at the radial center of the wound electrode body (that is, the wound central shaft portion). Features. Thus, the strength of the wound electrode body can be increased by providing the core material on the wound shaft portion of the wound electrode body.

  Embodiments according to the present invention will be described below with reference to the drawings. In the following drawings, members / parts having the same action are described with the same reference numerals. Hereinafter, the structure of the battery of the present invention will be described in detail using the lithium ion battery (secondary battery) 100 as an example. However, the present invention is not intended to be limited to the one described in the embodiment. Absent. In addition, the dimensional relationships (length, width, thickness, level of steps, etc.) in each figure are deformed to close up the features of the present invention, and do not reflect actual dimensional relationships.

  A configuration of a cylindrical single cell lithium ion battery 100 (hereinafter also simply referred to as “battery”) according to the present embodiment will be described with reference to FIG. FIG. 1 is an exploded perspective view schematically showing the configuration of the battery 100. The battery 100 disclosed here includes an electrode body 20 including current collector foil laminated portions 22a and 22b, and current collecting members 10a and 10b joined to the current collector foil laminated portions 22a and 22b of the electrode body 20. ing.

  The electrode body 20 is a wound electrode body 20 formed by winding a sheet-like electrode body 80 (FIG. 2) described later. The wound electrode body 20 of the present embodiment includes predetermined battery constituent materials (active materials for each of the positive and negative electrodes, current collectors for each of the positive and negative electrodes, a separator, and the like) as in a typical battery.

  A positive electrode current collector foil laminate portion 22a and a negative electrode current collector foil laminate portion 22b are formed at the end of the wound electrode body 20 in the winding axis direction. The positive electrode current collector foil laminated portion 22a and the negative electrode current collector foil laminated portion 22b correspond to the sheet-like positive electrode and sheet-like negative electrode active material-unformed portions described later, and constitute the positive electrode and the negative electrode of the wound electrode body 20, respectively. Yes. The material of the positive electrode current collector foil laminated portion 22a and the negative electrode current collector foil laminated portion 22b is not particularly limited as long as it is the same as that used in the conventional battery. For example, the positive electrode current collector foil laminated portion 22a made of aluminum and the negative electrode current collector foil laminated portion 22b made of copper can be suitably used.

  On the end surfaces in the winding axis direction of the positive electrode current collector foil laminated portion 22a and the negative electrode current collector foil laminated portion 22b, inclined surfaces 24a and 24b that are inclined with respect to the winding axis direction of the wound electrode body 20 are formed. . In the present embodiment, a concave surface having a substantially inverted conical shape (also referred to as a funnel shape or a bowl shape) is formed on the end faces of the current collector foil laminated portions 22a, 22b, and these are inclined surfaces 24a, 24b. In addition, such inclined surfaces 24a and 24b can be easily manufactured by making a sheet-like electrode body described later into a trapezoidal shape or a triangular shape, and winding the sheet-like electrode body.

  The current collecting members 10a and 10b are joined to the inclined surfaces 24a and 24b. The current collecting members 10a and 10b of the present embodiment are substantially conical members, and are configured such that the diameter (or cross-sectional area) increases from the inner side to the outer side in the winding axis direction. In the illustrated example, the positive electrode current collecting member 10a is joined to the inclined surface 24a on the positive electrode side, and the negative electrode current collecting member 10b is joined to the inclined surface 24b on the negative electrode side. The positive electrode current collector member 10a is made of the same material (here, aluminum) as the positive electrode current collector foil laminated portion 22a described above, and the negative electrode current collector member 10b is made of the same material (here, copper) as the negative electrode current collector foil laminated portion 22b mentioned above. Become.

  The current collecting members 10a and 10b have current collecting surfaces 14a and 14b joined to the inclined surfaces 24a and 24b of the current collecting foil laminated portions 22a and 22b. The current collecting surfaces 14a and 14b are formed to be inclined (parallel) to the inclined surfaces 24a and 24b. The current collecting surfaces 14a and 14b of the present embodiment correspond to the conical surfaces of the current collecting members 10a and 10b, and are substantially conical convex surfaces.

  Next, the junction structure of the current collector foil laminated portion of the wound electrode body and the current collector will be described. The current collector foil laminated portions 22a and 22b and the current collector members 10a and 10b are joined by joining their surfaces to each other. That is, the surfaces of the inclined surface 24a on the positive electrode side and the current collecting surface 14a on the positive electrode side are joined together, and the surfaces of the inclined surface 24b on the negative electrode side and the current collecting surface 14b on the negative electrode side are joined together.

  In addition, the inclined surfaces 24a and 24b and the current collecting surfaces 14a and 14b are joined with the conductive joining member 40 interposed therebetween. The conductive bonding member 40 is, for example, a low melting point alloy conductive material (solder in this example). That is, the solder 40 is supplied between the inclined surfaces 24a and 24b and the current collecting surfaces 14a and 14b (on the inclined surfaces 24a and 24b on the current collecting foil laminated portion side in FIG. 1), and the solder 40 is melted and solidified. By doing so, the inclined surfaces 24a and 24b and the current collecting surfaces 14a and 14b are welded. By this melting and solidification, the solder 40 spreads over the entire surface, so that the inclined surfaces 24a, 24b and the current collecting surfaces 14a, 14b are in surface contact. The solder 40 includes Sn—Bi, Sn—Pb, Sn—Ag solder alloys.

  Further, the conductive bonding member 40 may be any material that has conductivity and can bond the current collector foil laminated portion and the current collecting member, and as such a conductive bonding member 40, as described above. A low melting point alloy conductive material (solder in this example) is particularly preferred. The conductive bonding member 40 may be supplied to the inclined surfaces 24a and 24b as in the present embodiment, or may be supplied to the current collecting surfaces 14a and 14b. Alternatively, the conductive bonding member 40 can be supplied to both the inclined surfaces 24a and 24b and the current collecting surfaces 14a and 14b.

  According to the cylindrical battery 100 of the present embodiment, the current collector foil laminated portions 22a and 22b of the wound electrode body 20 and the current collecting members 10a and 10b are mutually facing each other (the inclined surfaces 24a and 24b and the current collecting surface 14a). 14b), it is not necessary to bundle the ends (current collector foil laminated portions 22a, 22b) of the wound electrode body 20, and the wound electrode body 20 is wrinkled or loosened. Can be avoided. Thereby, the bad influence (for example, exfoliation of an active material or non-uniform | heterogenous current density) which the wrinkles and slack which arose in the winding electrode body 20 have on battery performance can be prevented beforehand. Therefore, a highly reliable battery can be provided.

  Moreover, since the inclined surfaces 24a and 24b and the current collecting surfaces 14a and 14b easily come into surface contact by interposing the conductive bonding member 40 therebetween, the current collecting foil laminated portions 22a and 22b and the current collecting member 10a, The contact area with 10b can be increased. In addition, since the surfaces inclined with respect to the winding axis direction (inclined surfaces 24a and 24b and current collecting surfaces 14a and 14b) are joined, the contact area between the two becomes larger. Accordingly, the bonding strength between the current collecting foil laminated portions 22a and 22b and the current collecting members 10a and 10b can be improved, and the flow path of the current derived from the wound electrode body 20 to the current collecting members 10a and 10b. The area can be increased. As a result, current collection resistance is reduced, heat loss is reduced, and current collection efficiency is improved.

  In the present embodiment, the inclined surfaces 24a and 24b on the current collector foil laminated portion side are concave conical surfaces (funnels and reverse conical shapes), and the current collector surfaces 14a and 14b on the current collecting member side are conical. Although a convex surface is used, a large contact area can be obtained as long as the joint surface is inclined with respect to the winding axis direction. That is, the inclined surface on the current collecting foil laminated portion side may be a conical convex surface, and the current collecting surface on the current collecting member side may be an inverted conical concave surface. However, the inclined surfaces 24a, 24b are inverted conical concave surfaces, and the current collecting surfaces 14a, 14b are conical convex surfaces, so that part of the current collecting members 10a, 10b is fitted into the wound electrode body 20. The strength of the wound electrode body can be reinforced. In addition, the shape of the joint surface of the present embodiment is a conical shape. However, the shape is not limited to this. For example, the inclined surface and the current collecting surface are formed so as to be a substantially truncated cone-shaped joint surface with the tip portion cut off. be able to.

  Next, the configuration of the battery 100 of this embodiment, particularly the configuration of the wound electrode body 20, will be described with reference to FIGS. FIG. 2 is a diagram for explaining the configuration of the sheet-like electrode body, and FIG. 3 is an enlarged view of the main part schematically showing the main part of the cross section of the battery 100. Although FIG. 3 illustrates the positive electrode side, the embodiment can be applied to both the positive electrode side and the negative electrode side, and thus will be described without distinguishing between the positive electrode and the negative electrode.

  The wound electrode body 20 of the present embodiment is formed by winding a sheet electrode body 80 as shown in FIG. The sheet-like electrode body 80 has a long (band-like) sheet structure in a stage before assembling the wound electrode body 20. The sheet-like electrode body 80 according to the present embodiment is a sheet-like electrode 82a, 82b (specifically, a sheet-like positive electrode 82a (hereinafter, referred to as “positive electrode sheet 82a”), similarly to a wound electrode body of a typical battery. The sheet-like negative electrode 82b (hereinafter referred to as “negative electrode sheet 82b”) is laminated together with a total of two sheet-like separators 84 (hereinafter referred to as “separator sheet 84”).

  The positive electrode sheet 82a is formed by attaching a positive electrode active material layer 88a for a battery to both surfaces of a foil-shaped positive electrode current collector. However, the positive electrode active material layer 88a is not attached to one side edge (the upper side edge in FIG. 2) along the longitudinal direction of the positive electrode sheet 82a, and the positive electrode active material layer non-exposed with the positive electrode current collector foil exposed. A formation portion 86a is formed. The negative electrode sheet 82b has the same configuration as that of the positive electrode sheet 82a, and is formed by attaching a negative electrode active material layer 88b to both surfaces of a foil-like negative electrode current collector. A negative electrode active material layer non-forming portion 86b where the negative electrode current collector foil is exposed is formed on one side edge (the lower side edge in FIG. 2) of the negative electrode sheet 82b.

  When assembling the wound electrode body 20, first, a sheet-like electrode body 80 in which a positive electrode sheet 82 a and a negative electrode sheet 82 b are laminated via two separator sheets 84 is prepared. At this time, the separator sheet 84 has a positive electrode active material layer non-formation portion 86a of the positive electrode sheet 82a (a portion where the positive electrode current collector foil is exposed) 86a protruding outward (that is, the positive electrode active material layer formation portion 88a of the positive electrode sheet 82a and Overlapping is performed so that the separator sheet 84 faces the separator sheet 84. Similarly to the positive electrode sheet 82a, the negative electrode sheet 82b also has a negative electrode active material layer non-formed portion (a portion where the negative electrode current collector foil is exposed) 86b protrudes outward from the separator 84 (that is, the negative electrode active material layer of the negative electrode sheet 82b is formed). The portions 88b and the separator sheet 84 are overlapped).

  The sheet-like protruding portions 86a and 86b (specifically, the cathode-side protruding portion (positive electrode active material layer non-forming portion) 86a and the sheet-like negative electrode side protruding portion (negative electrode active material layer non-forming portion) 86b) It has a trapezoidal shape with different widths. That is, the width along the winding axis direction of the positive electrode side sheet-like protruding portion 86a and the negative electrode side sheet-like protruding portion 86b is from the upstream side to the downstream side in the traveling direction (winding direction) of the sheet-like electrode body 80 (in the drawing). It is configured to gradually narrow (from right to left). Thus, the positive electrode side sheet-like protruding portion 86a and the negative electrode side sheet-like protruding portion 86b are formed in a trapezoidal shape, whereby the sheet-like electrode body 80 is configured to have a trapezoidal shape as a whole.

  When such a trapezoidal sheet-shaped electrode body 80 is wound (here, approximately 30 times), it is as shown in FIG. That is, the winding core portion 23 (that is, the positive electrode active material layer forming portion 88a of the positive electrode sheet 82a, the negative electrode active material layer forming portion 88b of the negative electrode sheet 82b, and the separator) A portion in which the sheet 84 is densely stacked) is formed. Further, on the outer side of the winding core portion 23 in the winding axis direction, a positive electrode side sheet-like protruding portion (positive electrode active material layer non-forming portion) 86a is wound and laminated, whereby the positive electrode current collector foil laminated portion 22a. Is formed.

  Then, as a result of winding the sheet-like electrode body 80 (FIG. 2) in which the positive electrode protruding portion 86a is trapezoidal, the side edge portion 89a of the positive electrode-side protruding portion 86a is the winding axis of the wound electrode body 20. It will be laminated | stacked spirally, shifting | deviating little by little in a direction. That is, the side edge portion 89a arranged on the outer side in the radial direction of the wound electrode body 20 protrudes outward in the winding axis direction, and this protruding portion causes the conical concave surface (inclined surface 24a) of the positive electrode current collector foil laminated portion 22a. Is formed. On the negative electrode side, as in the positive electrode side, the side edge portion 89b of the negative electrode side sheet-like protruding portion (negative electrode active material layer non-forming portion) 86b is spirally shifted little by little in the winding axis direction of the wound electrode body 20. As a result, a conical concave surface (inclined surface 24b) of the negative electrode current collector foil laminated portion 22b is formed.

  Thus, the sheet-like electrode body 80 in which the positive electrode sheet-like protruding portion (positive electrode active material layer non-forming portion) 86a and the negative electrode sheet-like protruding portion (negative electrode active material layer non-forming portion) 86b are trapezoidally wound is wound. By doing so, the inclined surface 24a of the positive electrode current collector foil laminated portion 22a and the inclined surface 24b of the negative electrode current collector foil laminated portion 22b can be easily produced. It should be noted that the shape of the sheet protruding portion is not limited to the trapezoidal shape described above, and the same action and effect can be obtained even if it is a triangular shape, for example. Further, as shown in FIG. 2, the current collecting foil laminated portion after winding is cut by cutting the side edge portions 85 a and 85 b of the last one turn of the sheet-like electrode body 80 in parallel with the separator 84. Can be aligned horizontally.

  Preferably, as shown in FIGS. 1 and 3, the current collecting surfaces 14a and 14b of the current collecting members 10a and 10b correspond to the side edge portions 89a and 89b of the sheet-like protruding portions 86a and 86b in the wound state. Thus, it is formed in a step shape. That is, fine steps 16a and 16b are formed. The steps 16a and 16b of the present embodiment are spiral steps along the circumferential direction of the current collecting members 10a and 10b, and are provided continuously in the winding axis direction from the upper end to the lower end of the current collecting surfaces 14a and 14b. Yes. The stepped portions 16a and 16b are in contact with the side edges 89a and 89b of the side surfaces of the stepped portions 16a and 16b in the state where the inclined surfaces 24a and 24b and the current collecting surfaces 14a and 14b are joined via the solder 40. Configured to get. By providing steps on the current collecting surfaces 14a and 14b in this way, the side surfaces of the steps 16a and 16b and the side edge portions 89a and 89b can be brought into surface contact, and the current collecting surfaces 14a and 14b and the inclined surfaces 24a, The bonding strength with 24b can be further improved.

The solder 40 interposed between the current collecting surfaces 14a and 14b and the inclined surfaces 24a and 24b (particularly the steps 16a and 16b and the side edge portions 89a and 89b) is provided on the side of the sheet-like electrode body 80 in the pre-assembly stage. It is preferable to make it adhere in advance to the edge portions 89a and 89b (FIG. 2). Examples of such attachment means include application and immersion. Thereby, the solder 40 can be easily supplied between the current collecting surfaces 14a and 14b and the inclined surfaces 24a and 24b (particularly, the steps 16a and 16b and the side edge portions 89a and 89b).
Further, the melting of the solder 40 at the time of joining is preferably performed by bringing the current collecting surfaces 14a and 14b into contact with the inclined surfaces 24a and 24b. That is, the current collecting members 10a and 10b are heated in advance to be higher than the temperature at which the solder 40 is melted, and then the current collecting surfaces 14a and 14b are brought into contact with the inclined surfaces 24a and 24b, thereby making the solder 40 easy. Can be melted. In this configuration, it is not necessary to provide a separate melting process for the solder 40, and the battery manufacturing process can be simplified.

  An example of the structure of the battery 100 using the wound electrode body 20 and the current collecting members 10a and 10b assembled in this manner is shown in FIG. The battery 100 according to the present embodiment includes a wound electrode body 20 manufactured by the above-described method, current collecting members 10a and 10b, and an outer case 30 that houses the wound electrode body 20. In FIG. 4, a wound electrode body 20 having a smaller number of windings than actual is illustrated to simplify the drawing and facilitate the description of the present invention. Moreover, the thickness and level | step difference of the wound sheet | seat are also deformed.

  The battery 100 only needs to be the battery 100 including the wound electrode body 20 joined to the current collecting members 10a and 10b, and the configuration of the battery 100 is not particularly limited. A nickel hydride battery, an electric double layer capacitor, etc. are mentioned as a suitable battery structure for implementation of this invention. A battery configuration particularly suitable for the implementation of the present invention is a lithium ion secondary battery. Since the lithium ion secondary battery is a battery that can achieve a high output with a high energy density, it is possible to construct a high-performance power source, particularly a power source for mounting on a vehicle.

  The exterior case 30 has a shape (cylindrical shape in the present embodiment) that can accommodate the wound electrode body 20. Further, the material is not particularly limited as long as it is the same as that used in a typical battery, but a relatively light material can be used. For example, a metal case whose surface is preferably coated with an insulating resin coating, a polyolefin resin such as polypropylene, and other synthetic resin cases are suitable.

  The exterior case 30 has openings 32a and 32b (FIG. 1), and the wound electrode body 20 is accommodated inside the case via the openings 32a and 32b (FIG. 1). Openings 32a and 32b of the exterior case 30 are closed by current collecting members 10a and 10b. That is, the positive electrode current collecting member 10 a of the present embodiment is joined to the positive electrode current collector foil laminated portion 22 a of the wound electrode body 20 and closes the upper opening 32 a of the outer case 30. Similarly to the positive electrode current collector member 10 a, the negative electrode current collector member 10 b is joined to the negative electrode current collector foil laminated portion 22 b of the wound electrode body 20 and closes the opening 32 b below the outer case 30. In the said structure, the function as a cover body of the exterior case 30 can be provided to the current collection member 10a, 10b. Therefore, the number of battery components can be reduced. When the outer case 30 is made of metal, an insulating member (for example, a gasket or the like) that ensures insulation can be disposed between the outer case 30 and the current collecting members 10a and 10b.

  In addition, a core member 50 that is engaged with the current collecting members 10a and 10b is disposed at the center in the radial direction of the wound electrode body 20 (that is, the wound central shaft portion). The core material 50 of this embodiment is a rod-shaped member having insulation properties, and bridges the positive electrode current collector member 10a and the negative electrode current collector member 10b. By providing the core member 50 at the center of the wound electrode body 20 in this way, the strength of the wound electrode body 20 can be increased.

In addition, the material and member itself which comprise the winding electrode body 20 accommodated in this battery 100 may be the same as the electrode body of the conventional lithium ion battery, and there is no restriction | limiting in particular. For example, the positive electrode sheet 82a can be formed by applying a positive electrode active material layer for a lithium ion battery on a long positive electrode current collector. For the positive electrode current collector, an aluminum foil (this embodiment) or other metal foil suitable for the positive electrode is preferably used. For example, an aluminum foil having a length of 2 to 10 m, a width of 8 to 30 cm, and a thickness of about 5 to 20 μm (for example, 15 μm) can be used as the current collector. As the positive electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include LiMn ₂ O ₄ , LiCoO ₂ , LiNiO _{2 and the} like.

  On the other hand, the negative electrode sheet 82b can be formed by applying a negative electrode active material layer for a lithium ion battery on a long negative electrode current collector. For the negative electrode current collector, a copper foil (this embodiment) or other metal foil suitable for the negative electrode is preferably used. For example, a copper foil having a length of 2 to 10 m, a width of 8 to 30 cm, and a thickness of about 5 to 20 μm (for example, 10 μm) can be used as the current collector. As the negative electrode active material, one or more of materials conventionally used in lithium ion batteries can be used without any particular limitation. Preferable examples include carbon-based materials such as graphite carbon and amorphous carbon, lithium-containing transition metal oxides and transition metal nitrides.

  Moreover, as a suitable separator sheet 84 used between the positive and negative electrode sheets 82a and 82b, a sheet composed of a porous polyolefin resin can be used. For example, a porous separator sheet made of synthetic resin (for example, made of polyolefin such as polyethylene) having a length of 2 to 10 m, a width of 8 to 30 cm, and a thickness of about 5 to 30 μm (for example, 25 μm) can be suitably used. When a solid electrolyte or a gel electrolyte is used as the electrolyte, there may be a case where a separator is unnecessary (that is, in this case, the electrolyte itself can function as a separator).

Examples of the electrolyte accommodated together with the wound electrode body 20 in the outer case 30 include a lithium salt such as LiPF ₆ . An appropriate amount (for example, concentration 1M) of lithium salt such as LiPF ₆ is dissolved in a non-aqueous electrolyte such as a mixed solvent of diethyl carbonate and ethylene carbonate (for example, a mass ratio of 1: 1) and used as an electrolyte. it can.

  The battery 100 of this embodiment is constructed by housing the wound electrode body 20 in the outer case 30 described above, and then joining the current collecting members 10a and 10b to the wound electrode body 20 to close the outer case 30.

  The battery 100 according to the present embodiment can be suitably used as a power source for a motor (electric motor) mounted on a vehicle such as an automobile. That is, as shown in FIG. 5, the battery 100 according to the present embodiment (here, a cylindrical and wound battery) is arranged as a single cell in a predetermined direction, and the single cell is constrained in the arrangement direction. By constructing the assembled battery 72, a vehicle 70 (typically, an automobile equipped with an electric motor such as a hybrid car, an electric car, or a fuel cell car) provided with the assembled battery 72 as a power source can be provided.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible.

It is a disassembled perspective view which shows typically the structure of the winding type | mold (cylindrical type) battery of this embodiment. It is a figure for demonstrating the structure of the sheet-like electrode body of this embodiment. It is a principal part enlarged view which shows typically the principal part cross section of the battery of this embodiment. It is a figure which shows an example of the structure of the battery of this embodiment. It is a side view which shows typically the vehicle (automobile) provided with the battery of this embodiment. It is a figure which shows typically the current collection method of the battery provided with the conventional winding type electrode body. It is a figure which shows typically the current collection method of the battery provided with the conventional winding type electrode body.

Explanation of symbols

10a Positive electrode current collector member 10b Negative electrode current collector member 14a Positive electrode current collector surface 14b Negative electrode current collector surface 16a, 16b Step 20 Winding electrode body 22a Positive electrode current collector foil laminated portion 22b Negative electrode current collector foil laminated portion 23 Winding core portion 24a, 24b Inclined surface 30 Exterior case 32a, 32b Opening 40 Conductive bonding member 50 Core material 70 Vehicle 72 Battery pack 80 Sheet-like electrode body 82a Sheet-like positive electrode (positive electrode sheet)
82b Sheet-like negative electrode (negative electrode sheet)
84 Sheet separator (separator sheet)
86a Positive electrode active material layer non-formed part 86b Negative electrode active material layer non-formed part 88a Positive electrode active material layer formed part 88b Negative electrode active material layer formed part 89a, 89b Side edge part 100 Battery

Claims (9)

A wound electrode body formed by winding a sheet-like electrode having a foil-like current collector and a separator;
A current collecting member joined to an end face in the winding axis direction of the wound electrode body,
At the end in the winding axis direction of the wound electrode body, a current collector foil laminated portion joined to the current collector is formed,
The current collector foil laminated portion is a surface bonded to the current collector and has an inclined surface that is inclined with respect to the winding axis direction;
The current collecting member has a current collecting surface that is a surface bonded to the current collecting foil laminated portion and is inclined to face the inclined surface.
Here, the current collecting foil laminated portion and the current collecting member are joined in a state where a conductive joining member is interposed between the inclined surface and the current collecting surface. .   The battery according to claim 1, wherein the inclined surface is an inverted conical concave surface, and the current collecting surface is a conical convex surface. The sheet-like electrode has a sheet-like protruding portion that is rolled out from the separator,
3. The battery according to claim 1, wherein a planar shape of the sheet-shaped electrode including the sheet protruding portion in a developed state is a trapezoidal shape or a triangular shape. The current collector foil laminated portion is formed by winding the sheet-like protruding portion,
The battery according to claim 3, wherein the inclined surface of the current collector foil laminated portion is formed by a side edge portion of the sheet-like protruding portion in the wound state. The current collecting surface of the current collecting member is formed in a step shape so as to correspond to a side edge portion of the sheet-like protruding portion in the wound state,
The battery according to claim 4, wherein the inclined surface and the current collecting surface are joined in a surface contact state with the conductive joining member interposed therebetween.   The battery according to claim 3, wherein the conductive bonding member is attached to a side edge portion of the sheet-like protruding portion. An exterior case that houses the wound electrode body;
The battery according to claim 1, wherein an opening of the outer case is closed by the current collecting member.   The battery according to any one of claims 1 to 7, wherein a core member engaged with the current collecting member is disposed at a center in a radial direction of the wound electrode body.   A vehicle comprising the battery according to claim 1.

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