JP2005340005A - Secondary battery and battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery preventing the deformation or distortion of an electrode terminal generating in being joined to an electrode terminal of other secondary battery. <P>SOLUTION: The secondary battery 10 is constituted in such a way that electrode plates 101, 103 stacked through a separator 102 are housed and sealed in outer jacket members 106, 107, electrode terminals 104, 105 connected to the electrode plates 101, 103 are taken out of the outer peripheral edges of the the outer jacket members 106, 107, and the electrode terminals 104, 105 are formed so that the thickness T<SB>1</SB>of tip parts 104a, 105a taken out of the outer jackets 106, 107 is made relatively thicker than the thickness T<SB>2</SB>of the sealing parts 104b, 105b sealed in the outer jacket members 106, 107 (T<SB>1</SB>>T<SB>2</SB>). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a secondary battery in which an electrode plate is stacked through a separator, accommodated in an exterior member and sealed, and an electrode terminal connected to the electrode plate is led out from the exterior member and the secondary battery. The present invention relates to an assembled battery configured by connecting a plurality thereof.

  In order to secure a desired capacity and voltage in a secondary battery in which electrode plates are stacked through a separator, accommodated in an exterior member and sealed, and electrode terminals connected to the electrode plate are led out from the exterior member. In addition, a technique is known in which an assembled battery is configured by combining a plurality of secondary batteries by directly connecting electrode terminals derived from each secondary battery (see, for example, Patent Document 1).

  In such an assembled battery, in order to securely connect each secondary battery, the electrode terminals of the secondary battery are joined by a technique such as ultrasonic welding, for example. Since it is composed of a metal thin film such as a copper foil, deformation or distortion occurs during welding, and when an external force such as vibration acts on each secondary battery, there is a possibility that the welded part may peel off.

On the other hand, if the electrode terminal is simply thickened in order to suppress deformation and distortion during welding, it is easy to radiate heat from this electrode terminal made of a metal material or the like when sealing the outer peripheral edge of the exterior member of the secondary battery. It becomes difficult to seal the exterior member.
Japanese Patent Laid-Open No. 9-259859

An object of this invention is to provide the secondary battery and assembled battery which prevented that an electrode terminal deform | transformed and distortion | strained at the time of joining.
In order to achieve the above object, according to the present invention, an electrode plate laminated via a separator is accommodated in an exterior member and sealed, and an electrode terminal connected to the electrode plate is an outer peripheral edge of the exterior member. The electrode terminal has a relative thickness with respect to the thickness of the sealed portion sealed by the exterior member. A secondary battery that is formed thick is provided.

  In the present invention, in the electrode terminal of the secondary battery, the thickness of the tip portion on the side led out from the exterior member is made relatively thicker than the thickness of the sealing portion sealed by the exterior member. As a result, strong strength is imparted to the tip portion of the electrode terminal. Therefore, when an assembled battery is configured using a plurality of secondary batteries, the electrode terminals are joined at the tip portion by joining the electrode terminals together. It is possible to prevent deformation and distortion from occurring.

  In order to achieve the above object, according to the present invention, an electrode plate laminated via a separator is accommodated and sealed in an exterior member, and an electrode terminal connected to the electrode plate is connected to the exterior member. An assembled battery comprising a plurality of secondary batteries derived from an outer peripheral edge, wherein the plurality of secondary batteries are electrically connected by joining the electrode terminals of the secondary batteries. In the electrode terminal of the secondary battery, the thickness of the joined portion joined to the electrode terminal of the other secondary battery is relatively thicker than the thickness of the sealed portion sealed by the exterior member. A formed assembled battery is provided.

  In the present invention, in the electrode terminal of each secondary battery that constitutes the assembled battery, the thickness of the bonded portion that is bonded to the electrode terminal of the other secondary battery is the thickness of the sealed portion that is sealed to the exterior member. To be relatively thick. As a result, strong strength is imparted to the joined portion, so that it is possible to prevent deformation and distortion of the electrode terminal during joining.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a plan view of the entire secondary battery according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the secondary battery taken along line II-II in FIG.

  1 and 2 show one secondary battery 10 (unit battery), and an assembled battery having a desired voltage and capacity is configured by stacking a plurality of secondary batteries 10.

  The secondary battery 10 according to the first embodiment of the present invention is a lithium-based flat stacked thin secondary battery, and includes three positive plates 101 and 5 as shown in FIGS. The separator 102, the three negative plates 103, the positive electrode terminal 104, the negative electrode plate 105, the upper exterior member 106, the lower exterior member 107, and the electrolyte not shown in particular are comprised. Among these, the positive electrode plate 101, the separator 102, the negative electrode plate 103, and the electrolyte are particularly referred to as a power generation element 108.

  The positive electrode plate 101 constituting the power generation element 108 includes a positive electrode side current collector 101a extending to the positive electrode terminal 104, and positive electrode layers 101b and 101c formed on both main surfaces of a part of the positive electrode side current collector 101a, respectively. have. In addition, the positive electrode layers 101b and 101c of the positive electrode plate 101 are not formed over both main surfaces of the entire positive electrode current collector 101a, but as shown in FIG. When the power generation element 108 is configured by laminating the negative electrode plate 103, the positive electrode layers 101 b and 101 c are formed only on the portion of the positive electrode plate 101 that substantially overlaps the separator 102.

  The positive electrode side current collector 101a of the positive electrode plate 101 is an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil.

The positive electrode layers 101b and 101c of the positive electrode plate 101 are made of, for example, lithium composite oxide such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), or lithium cobaltate (LiCoO ₂ ), or chalcogen. A mixture of a positive electrode active material such as (S, Se, Te) compound, a conductive agent such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene is used for the positive electrode side current collector 101a. It is formed by applying to some of both main surfaces, drying and rolling.

  The negative electrode plate 103 constituting the power generation element 108 includes a negative electrode side current collector 103a extending to the negative electrode terminal 105, and negative electrode layers 103b and 103c formed on both main surfaces of a part of the negative electrode side current collector 103a, respectively. And have. Note that the negative electrode layers 103b and 103c of the negative electrode plate 103 are not formed over both main surfaces of the entire negative electrode side current collector 103a, but as shown in FIG. When the power generation element 108 is configured by laminating the negative electrode plate 103, the negative electrode layers 103 b and 103 c are formed only on the portion of the negative electrode plate 103 that substantially overlaps the separator 102.

  The negative electrode side current collector 103a of the negative electrode plate 103 is an electrochemically stable metal foil such as nickel foil, copper foil, stainless steel foil, or iron foil.

  Further, the negative electrode layers 103b and 103c of the negative electrode plate 10 occlude and release lithium ions of the positive electrode active material such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, or graphite. An aqueous dispersion of styrene butadiene rubber resin powder as a precursor material of an organic fired body is mixed with the negative electrode active material, and dried and pulverized to support carbonized styrene butadiene rubber on the carbon particle surfaces. It is formed by mixing a binder, such as an acrylic resin emulsion, and applying this mixture to both main surfaces of a part of the negative electrode current collector 103a, followed by drying and rolling. Yes.

  In particular, when amorphous carbon or non-graphitizable carbon is used as the negative electrode active material, the flatness of the potential during charge / discharge is poor and the output voltage decreases with the amount of discharge. Although unsuitable, it is advantageous when used as a power source for an electric vehicle because there is no sudden drop in output.

  The separator 102 of the power generation element 108 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 described above, and may have a function of holding an electrolyte. This separator 102 is a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP), for example. When an overcurrent flows, the pores of the layer are blocked by the heat generation and the current is cut off. It also has a function to

  The separator of the present invention is not limited to a single-layer film such as polyolefin, but may be a three-layer structure in which a polypropylene film is sandwiched with a polyethylene film, or a laminate of a polyolefin microporous film and an organic nonwoven fabric. By forming the separator in multiple layers in this manner, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (rigidity improvement) function can be provided.

  In the power generation element 108 described above, the positive electrode plates 101 and the negative electrode plates 103 are alternately stacked via the separators 102. The three positive plates 101 are respectively connected to the positive terminal 104 made of metal foil via the positive current collector 101a, while the three negative plates 103 are connected to the negative current collector 103a. In the same manner, each is connected to a negative electrode terminal 105 made of metal foil.

  In addition, the positive electrode plate 101, the separator 102, and the negative electrode plate 103 of the power generation element 108 are not limited to the above number in the present invention. For example, one positive electrode plate 101, three separators 102, and 1 The power generation element 108 can also be configured with a single negative plate 103, and can be configured by selecting the number of positive plates, separators, and negative plates as required.

  The positive electrode terminal 104 and the negative electrode terminal 105 are not particularly limited as long as they are electrochemically stable metal materials. Examples of the positive electrode terminal 104 include, for example, an aluminum foil and an aluminum alloy foil, similar to the positive electrode current collector 101a described above. , Copper foil, or nickel foil. Moreover, as the negative electrode terminal 105, nickel foil, copper foil, stainless steel foil, iron foil, etc. can be mentioned similarly to the above-mentioned negative electrode side collector 103a, for example. In the present embodiment, the metal foil itself constituting the current collectors 101 a and 103 a of the electrode plates 101 and 103 is extended to the electrode terminals 104 and 105, so that the electrode plates 101 and 103 are directly connected to the electrode terminals 104 and 105. Although connected, the current collectors 101a and 103a of the electrode plates 101 and 103 and the electrode terminals 104 and 105 are connected by a material or component different from the metal foil constituting the current collectors 101a and 103a. Also good.

Further, as shown in FIG. 2, the positive terminal 104 of the secondary battery 10 according to the present embodiment has a thickness T _{1 of} a tip portion (joining portion) 104 a on the side led out from the exterior members 106 and 107. the package member 106 and 107 are relatively thick with respect to the thickness _{T 2} of the sealed closing portion 104b to _{(T 1>} T 2), towards the sealing portion 104b to the distal end portion 104a The thickness of the positive electrode terminal 104 is formed so as to increase stepwise, and both main surfaces of the positive electrode terminal 104 are formed to be substantially parallel at the tip portion 104a.

  Incidentally, as will be described later, when a plurality of secondary batteries 10 are connected in series or in parallel to form a battery pack, the tip terminal portion 104a of the positive terminal 104 is used as an electrode terminal 104 of another secondary battery 10. , 105 are joined by a technique such as ultrasonic welding, spot welding, or cold welding.

Further, as shown in FIG. 1, the positive terminal 104 corresponds to the thickness of the positive terminal 104 so that the cross-sectional area of the positive terminal 104 with respect to the derivation direction is substantially constant over the derivation direction. Te, from the sealing portion 104b to the distal end portion 104a and the width of the positive electrode terminal 104 is formed so as to decrease stepwise, for example, the width _{W 1} of the distal end portion 104a is, the width _{W 2} of the sealing portion 104b It is relatively narrower with respect to _(W 1 _<W 2), the cross-sectional area _{S 1 (= T 1 × W} 1) at the tip portion 104a, the cross sectional area _S 2 in the sealing portions 104b (= _{T 2} × W ₂ ) is substantially the same (S ₁ = S ₂ ).

  Similarly, as shown in FIG. 2, the negative electrode terminal 105 of the secondary battery 10 according to the present embodiment has a thickness of the front end portion (joining portion) 105 a that is led out from the exterior members 106 and 107. It is formed relatively thick with respect to the thickness of the sealing portion 105b sealed by the exterior members 106 and 107, and the thickness of the negative electrode terminal 105 is stepped from the sealing portion 105b toward the tip portion 105a. In addition to being formed to increase, both main surfaces of the negative electrode terminal 105 are formed to be substantially parallel at the tip portion 105a.

  Incidentally, as will be described later, when a plurality of secondary batteries 10 are connected in series or in parallel to form a battery pack, the tip terminal portion 105a of the negative electrode terminal 105 is used as an electrode terminal 104 of another secondary battery 10. , 105 are joined by a technique such as ultrasonic welding, spot welding, or cold welding.

  Further, as shown in FIG. 1, the negative electrode terminal 105 is formed such that the width of the tip portion 105a is relatively narrow with respect to the width of the sealing portion 105b, and the cross-sectional area of the negative electrode terminal 105 with respect to the lead-out direction. Corresponding to the thickness of the negative electrode terminal 105 so that the width of the negative electrode terminal decreases stepwise from the sealing portion 105b toward the tip portion 105a. Is formed.

  As described above, by increasing the thickness of the tip portions 104a and 105a relative to the thickness of the sealing portions 104b and 105b in the electrode terminals 104 and 105, strong strength is imparted to the tip portions 104a and 105a. Therefore, when the electrode terminals 104 and 105 are joined to form an assembled battery, it is possible to suppress deformation and distortion of the electrode terminals 104 and 105. In addition, since the electrode terminals 104 and 105 of the secondary battery 10 are not deformed or distorted, the secondary battery 10 can be easily aligned when configuring the assembled battery.

  Furthermore, in the electrode terminals 104 and 105 of the secondary battery 10, the cross-sectional area with respect to the derivation direction is made substantially the same over the derivation direction, so that the current density in the electrode terminals 104 and 105 becomes constant, and the voltage Descent and energy loss can be suppressed.

  The power generation element 108 is housed and sealed in an upper exterior member 106 and a lower exterior member 107 (exterior member). Both the upper exterior member 106 and the lower exterior member 107 in the present embodiment are not particularly illustrated, but for example, polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer from the inside to the outside of the secondary battery 10. An inner layer composed of a resin film excellent in electrolytic solution resistance and heat-fusibility, an intermediate layer composed of a metal foil such as aluminum, and a polyamide resin or a polyester resin, for example It has a three-layer structure composed of an outer layer made of a resin film excellent in electrical insulation.

  Therefore, in both the upper exterior member 106 and the lower exterior member 107, for example, one surface (inner surface of the secondary battery 10) of a metal foil such as an aluminum foil is laminated with polyethylene and the other surface (secondary battery). 10 outer surface) is laminated with a polyamide-based resin or the like, and is formed of a flexible material such as a resin-metal thin film laminate material.

  As described above, since the exterior member includes the metal layer in addition to the resin layer, the strength of the exterior member itself can be improved. In addition, the inner layer of the exterior member can be made of, for example, a resin such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer, thereby ensuring good fusing property with a metal electrode terminal. It becomes possible.

  As shown in FIGS. 1 and 2, the positive terminal 104 is led out from one end of the sealed exterior members 106 and 107, and the negative terminal 105 is led out from the other end. Since a gap is formed in the fusion part between the upper exterior member 106 and the lower exterior member 107 by the thickness of 104, 105, the electrode terminals 104, 105 and the exterior are maintained in order to maintain the sealing performance inside the secondary battery 10. For example, a seal film made of polyethylene, polypropylene, or the like may be interposed at a portion where the members 106 and 107 come into contact. It is preferable from the viewpoint of heat-fusibility that this seal film is made of the same type of resin as the resin constituting the exterior members 106 and 107 in both the positive electrode terminal 104 and the negative electrode terminal 105.

  These exterior members 106 and 107 enclose the power generation element 108, part of the positive electrode terminal 104 and part of the negative electrode terminal 105 described above, and in the space formed by the exterior members 106 and 107, perchloric acid is added to the organic liquid solvent. While injecting a liquid electrolyte having a lithium salt such as lithium oxide, lithium borofluoride or lithium hexafluorophosphate as a solute, the space formed by the exterior members 106 and 107 is sucked into a vacuum state, and then the exterior member The outer peripheral edges of 106 and 107 are sealed by heat fusion by hot pressing.

  Examples of the organic liquid solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate, but the organic liquid solvent of the present invention is limited to this. It is also possible to use an organic liquid solvent prepared by mixing and preparing an ether solvent such as γ-butylactone (γ-BL) and dietoshietane (DEE) in the ester solvent.

  FIG. 3 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the first embodiment of the present invention in parallel, and FIG. 4 shows electrode terminals of the secondary battery in the first embodiment of the present invention. It is a schematic diagram of the ultrasonic welding to join.

  The assembled battery 20 shown in FIG. 3 is an assembled battery configured by connecting two secondary batteries 10a and 10b in parallel, in a posture such that the same polarity terminals 104 are led out in substantially the same direction, and The lower exterior member 107 is closely adhered and laminated.

  As shown in FIG. 4, the battery terminals 20 of the battery pack 20 have a thickest joining portion (tip portion) 104 a sandwiched between the horn H and the receiving jig D, and are not particularly illustrated. By transmitting vibration from the sound wave vibrator to the positive electrode terminal 104 via the horn H, the positive electrode terminals 104 are ultrasonically welded to each other.

  Similarly, the negative electrode terminals 105 of the battery pack 20 are not particularly shown, but the ultrasonic vibrators are connected to the horn H with the thickest tip portion 105a sandwiched between the horn H and the receiving jig D. The vibration is transmitted to the negative electrode terminal 105 via the electrode, so that the negative electrode terminals 105 are ultrasonically welded to each other.

  Thus, in this embodiment, in the assembled battery 20 configured by connecting a plurality of secondary batteries 10a and 10b in parallel, a joint portion 104a that joins the electrode terminals 104 and 105 of the secondary batteries 10a and 10b, By increasing the thickness of 105a to give strong strength, it is possible to prevent the electrode terminals 104 and 105 from being deformed or distorted during bonding.

  Further, in the assembled battery 20 according to the present embodiment, the joint portions 104a and 105a of the electrode terminals 104 and 105 are formed so that both main surfaces of the electrode terminals 104 and 105 are substantially parallel to each other. In the ultrasonic welding, since the joint portions 104a and 105a are substantially parallel to the vibration direction of the horn H, it is possible to ensure a strong joint strength.

  FIG. 5 is a side view showing an example of an assembled battery configured by connecting the secondary batteries according to the first embodiment of the present invention in series.

  The assembled battery 30 shown in FIG. 5 is an assembled battery configured by connecting three secondary batteries 10a to 10c in series. In this assembled battery 30, the adjacent secondary batteries 10a to 10c are arranged in an inverted state, and the different polarity terminals 105 and 104 of the adjacent secondary batteries 10a to 10c are electrically connected to each other. .

  The different polarity terminals 105 and 104 of the assembled battery 30 are not particularly illustrated, but the ultrathin joint portions (tip portions) 105a and 104a are sandwiched between the horn H and the receiving jig D, As shown in FIG. 5, ultrasonic welding is performed at the tip portions 105a and 104a by transmitting vibrations from the acoustic wave vibrator to the different polarity terminals 105 and 104 through the horn H.

  Thus, in the present embodiment, in the assembled battery 30 configured by connecting a plurality of secondary batteries 10a to 10c in series, a joint portion 104a that joins the electrode terminals 104 and 105 of the secondary batteries 10a to 10c, By increasing the thickness of 105a to give strong strength, it is possible to prevent the electrode terminals 104 and 105 from being deformed or distorted during bonding.

  Further, in the assembled battery 30 according to the present embodiment, the joint portions 104a and 105a of the electrode terminals 104 and 105 are formed so that both main surfaces of the electrode terminals 104 and 105 are substantially parallel. In the ultrasonic welding, since the joint portions 104a and 105a are substantially parallel to the direction of vibration transmitted through the horn H, it is possible to ensure a strong joint strength. .

[Second Embodiment]
6 is an enlarged plan view of a terminal lead-out portion of the secondary battery according to the second embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

  The secondary battery 10 ′ according to the second embodiment of the present invention is different from the secondary battery 10 according to the first embodiment described above in that the shapes of the electrode terminals 104 ′ and 105 ′ are different. The configuration is the same as that of the secondary battery 10 according to the first embodiment. Hereinafter, only the difference between the secondary battery 10 ′ according to the second embodiment and the secondary battery according to the first embodiment will be described.

As shown in FIGS. 6 and 7, the positive terminal 104 ′ of the secondary battery 10 ′ according to the present embodiment has a distal end portion (from the exterior members 106 and 107), as in the first embodiment. The thickness T ₁ ′ of the joining portion) 104a ′ is formed relatively thicker than the thickness T ₂ ′ of the sealing portion 104b ′ sealed by the exterior members 106 and 107 (T ₁ ′). > T ₂ ').

  However, unlike the first embodiment, the positive electrode terminal 104 ′ in the present embodiment has a flat inclined surface 104c ′ that is inclined from the sealing portion 104b ′ toward the tip portion 104a ′, as shown in FIG. The positive electrode terminal 104 ′ is formed so as to continuously increase in thickness from the sealing portion 104b ′ to the tip portion 104a ′.

Further, as in the first embodiment, the positive terminal 104 ′ has a width W ₁ ′ of the tip portion 104a ′ relative to the width W ₂ ′ of the sealing portion 104b ′ as shown in FIG. (W ₁ ′ <W ₂ ′), the cross-sectional area S ₁ ′ (= T ₁ ′ × W ₁ ′) at the tip portion 104 a ′, and the cross-sectional area S ₂ ′ at the sealing portion 104 b ′ ( = T ₂ ′ × W ₂ ′) is substantially the same (S ₁ ′ = S ₂ ′).

  However, as shown in the figure, the positive electrode terminal 104 ′ in the present embodiment is different from the first embodiment in that the cross-sectional area of the positive electrode terminal 104 ′ in the derivation direction is substantially constant over the derivation direction. Thus, the width of the positive electrode terminal 104 ′ is continuously reduced from the sealing portion 104b ′ toward the tip portion 104a ′ corresponding to the thickness of the positive electrode terminal 104 ′.

  Similarly, the negative electrode terminal 105 ′ of the secondary battery 10 ′ according to the present embodiment is not particularly illustrated, but the thickness of the tip portion 105a ′ on the side led out from the exterior members 106 and 107 is different from that of the exterior members 106 and 107. It is formed relatively thick with respect to the thickness of the sealed sealing portion 105b ′, and an inclined surface 105c ′ that is inclined from the sealing portion 105b ′ toward the tip portion 105a ′ is formed. The thickness of the negative electrode terminal 105 ′ is continuously increased from the sealing portion 105b ′ to the tip portion 105a ′.

  Further, the negative electrode terminal 105 ′ is formed such that the width of the tip portion 105a ′ is relatively narrow with respect to the width of the sealing portion 105b ′, and the cross-sectional area at the tip portion 105a ′ and the sealing portion 105b ′. Corresponding to the thickness of the negative electrode terminal 105 ′ so that the cross-sectional area of the negative electrode terminal 105 ′ with respect to the derivation direction is substantially constant over the derivation direction. Thus, the width of the negative electrode terminal 105 ′ is continuously reduced from the sealing portion 105b ′ toward the tip portion 105a ′.

  In this way, by increasing the thickness of the tip portions 104a ′, 105a ′ relative to the thickness of the sealing portions 104b ′, 105b ′ in the electrode terminals 104 ′, 105 ′, the tip portions 104a ′, A strong strength can be imparted to 105a ', and when the electrode terminals 104' and 105 'are joined together to form an assembled battery, the deformation and distortion of the electrode terminals 104' and 105 'are suppressed. Is possible. In addition, since the electrode terminals 104 ′ and 105 ′ of the secondary battery 10 ′ are not deformed or distorted, the secondary battery 10 ′ can be easily aligned when configuring the assembled battery.

  Further, in each electrode terminal 104 ′, 105 ′, by making the cross-sectional area with respect to the derivation direction substantially the same over the derivation direction, the current density in the electrode terminals 104 ′, 105 ′ becomes constant, and the voltage Descent and energy loss can be suppressed.

  Further, in the secondary battery 10 ′ according to the present embodiment, the thickness of the electrode terminals 104 ′ and 105 ′ is continuously decreased from the sealing portions 104b ′ and 105b ′ toward the tip portions 104a ′ and 105a ′. As a result, it is possible to eliminate a portion where stress is concentrated in the electrode terminals 104 ′ and 105 ′.

  FIG. 8 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the second embodiment of the present invention in parallel.

  The assembled battery 20 ′ shown in FIG. 8 is an assembled battery configured by connecting two secondary batteries 10 a ′ and 10 b ′ in parallel as in the assembled battery 20 according to the first embodiment. It is configured by sticking and stacking the lower battery exterior members 107 in a posture such that they are led out in substantially the same direction.

  The positive terminals 104 ′ of the assembled battery 20 ′ are not particularly illustrated, but a thick joint portion (tip portion) 104 a ′ is sandwiched between the horn H and the receiving jig D as in the first embodiment. In this state, by transmitting vibration from the ultrasonic vibrator through the horn H, ultrasonic welding is performed at the joint portion 104a ′ as shown in FIG. Similarly, the negative terminals 105 ′ of the assembled battery 20 ′ are also ultrasonically welded at the joint portion 105 a ′.

  Thus, in this embodiment, in the assembled battery 20 ′ configured by connecting a plurality of secondary batteries 10a ′ and 10b ′ in parallel, the electrode terminals 104 and 105 of the secondary batteries 10a ′ and 10b ′ are joined together. By increasing the thickness of the joining portions 104a ′ and 105a ′ to be applied and imparting strong strength, it is possible to prevent the electrode terminals 104 ′ and 105 ′ from being deformed or distorted during joining.

  FIG. 9 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the second embodiment of the present invention in series.

  The assembled battery 30 ′ shown in FIG. 9 is an assembled battery configured by connecting three secondary batteries 10a ′ to 10c ′ in series, like the assembled battery 30 according to the first embodiment, and is adjacent to the secondary battery. Different polarity terminals 105 ′ and 104 ′ of the batteries 10a ′ to 10c ′ are electrically connected to each other.

  As shown in FIG. 9, the assembled battery 30 ′ according to the present embodiment has the inclined surfaces 105 c ′ and 104 c included in the electrode terminals 105 ′ and 104 ′ with the adjacent secondary batteries 10 a ′ to 10 c ′ turned upside down. In a state where the two are overlapped with each other, ultrasonic welding is performed at the joint portions 105a 'and 104a'.

  More specifically, as shown in FIG. 9, the first secondary battery 10a ′ and the secondary battery 10b ′ adjacent to the first secondary battery 10a ′ are turned upside down. The slope 105c ′ included in the negative electrode terminal 105 ′ of the first secondary battery 10a ′ and the slope 104c ′ included in the positive electrode terminal 104 ′ of the second secondary battery 10b ′ are overlapped to form the joint portion 105a ′. 104a ′, the different polarity terminals 105 ′ and 104 ′ are ultrasonically welded to each other.

  Similarly, as shown in the figure, the second secondary battery 10b ′ and the secondary battery 10c ′ adjacent to the second secondary battery 10b ′ are turned over with each other in the second state. The slope 105c ′ of the negative electrode terminal 105 ′ of the secondary battery 10b ′ and the slope 104c ′ of the positive terminal 104 ′ of the third secondary battery 10c ′ are overlapped to form the joint portions 105a ′ and 104a ′. Thus, the different polarity terminals 105 ′ and 104 ′ are ultrasonically welded to each other.

  Thus, in this embodiment, in the assembled battery 30 ′ configured by connecting a plurality of secondary batteries 10a ′ to 10c ′ in series, the electrode terminals 104 ′ and 105 ′ of the secondary batteries 10a ′ to 10c ′ are connected to each other. By increasing the thickness of the joining portions 104a ′ and 105a ′ for joining the electrodes, it is possible to prevent deformation and distortion of the electrode terminals 104 ′ and 105 ′ during joining. Yes.

[Third Embodiment]
FIG. 10 is an enlarged plan view of a terminal lead-out portion of the secondary battery according to the third embodiment of the present invention, and FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG.

  The secondary battery 10 ″ according to the third embodiment of the present invention is different from the secondary battery 10 according to the first embodiment described above in that the electrode terminals 104 ″ and 105 ″ are different in shape. The configuration is the same as that of the secondary battery 10 according to the first embodiment. Hereinafter, only the difference from the secondary battery according to the first embodiment will be described for the secondary battery 10 "according to the third embodiment.

As shown in FIG. 11, the positive terminal 104 ″ of the secondary battery 10 ″ according to the present embodiment is, as in the first embodiment, the leading end portion (joint portion) on the side led out from the exterior members 106 and 107. The thickness T ₁ ″ of 104 a ″ is formed relatively thicker than the thickness T ₂ ″ of the sealing portion 104 b ″ sealed by the exterior members 106 and 107 (T ₁ ″> T ₂ ").

  However, unlike the first embodiment, the positive electrode terminal 104 ″ in this embodiment has a flat inclined surface 104c ″ that is inclined from the sealing portion 104b ″ to the tip portion 104a ″, as shown in FIG. The positive electrode terminal 104 ″ is formed so that the thickness of the positive electrode terminal 104 ″ increases continuously from the sealing portion 104b ″ to the tip portion 104a ″, and both main surfaces of the positive electrode terminal 104 ″ are formed at the joint portion 104a ″. Are formed so as to be substantially parallel.

Further, as in the first embodiment, the positive terminal 104 ″ has a width W ₁ ″ of the tip portion 104a ″ relative to the width W ₂ ″ of the sealing portion 104b ″ as shown in FIG. (W ₁ ″ <W ₂ ″), the cross-sectional area S ₁ ″ (= T ₁ ″ × W ₁ ″) at the tip end portion 104 a ″ and the cross-sectional area S ₂ ″ (at the sealing portion 104 b ″). = T ₂ ″ × W ₂ ″) is substantially the same (S ₁ ″ = S ₂ ″).

  However, unlike the first embodiment, the positive electrode terminal 104 ″ in this embodiment differs from the first embodiment in that the cross-sectional area of the positive electrode terminal 104 ″ with respect to the derivation direction in the positive electrode terminal 104 ″ is substantially in the derivation direction. In correspondence with the thickness of the positive electrode terminal 104 ″, the width of the positive electrode terminal 104 ″ decreases continuously from the sealing portion 104b ″ to the tip portion 104a ″, When reaching the portion 104a ″, the width of the positive electrode terminal 104 ″ is constant corresponding to the tip portion 104a ″ where the thickness of the positive electrode terminal 104 ″ is constant.

  Similarly, the negative electrode terminal 105 ″ of the secondary battery 10 ″ according to the present embodiment is not particularly illustrated, but the thickness of the tip portion 105a ″ on the side led out from the exterior members 106, 107 is such that the exterior member 106, A flat inclined surface 105c ″ is formed so as to be relatively thick with respect to the thickness of the sealing portion 105b ″ sealed by 107, and is inclined from the sealing portion 105b ″ toward the tip portion 105a ″. The negative electrode terminal 105 ″ is formed so that the thickness of the negative electrode terminal 105 ″ increases continuously from the sealing portion 105b ″ to the bonding portion 105a ″, and both main surfaces of the negative electrode terminal 105 ″ are formed at the bonding portion 105a ″. Are formed so as to be substantially parallel.

  Further, the negative electrode terminal 105 ″ is formed such that the width of the bonding portion 105a ″ is narrower than the width of the sealing portion 105b ″, and the cross-sectional area at the bonding portion 105a ″ and the cross-sectional area at the sealing portion 105b ″ Corresponding to the thickness of the negative electrode terminal 105 ″ so that the cross-sectional area of the negative electrode terminal 105 ″ with respect to the derivation direction is substantially constant over the derivation direction. The width of the negative electrode terminal 105 ″ continuously decreases from the stop portion 105b ″ to the tip portion 105a ″, and when the tip portion 105a ″ is reached, the thickness of the negative electrode terminal 105 ″ becomes constant. Corresponding to "", the width of the negative electrode terminal 105 "is constant.

  In this way, by increasing the thickness of the tip portions 104a "and 105a" in the electrode terminals 104 "and 105" relative to the thickness of the sealing portions 104b "and 105b", the tip portions 104a "and 105a" It is possible to give a strong strength to 105a "and suppress the deformation and distortion of the electrode terminals 104" and 105 "when joining the electrode terminals 104" and 105 "to form an assembled battery. Is possible. In addition, since the electrode terminals 104 ″ and 105 ″ of the secondary battery 10 ″ are not deformed or distorted, the secondary battery 10 ″ can be easily aligned when configuring the assembled battery.

  Further, in each electrode terminal 104 ″, 105 ″, by making the cross-sectional area with respect to the derivation direction substantially the same over the derivation direction, the current density in the electrode terminals 104 ″, 105 ″ becomes constant, and the voltage Descent and energy loss can be suppressed.

  FIG. 12 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the third embodiment of the present invention in parallel.

  Similar to the assembled battery 20 according to the first embodiment, the assembled battery 20 ″ shown in FIG. 12 is an assembled battery configured by connecting two secondary batteries 10a ″ and 10b ″ in parallel. "The positions are such that they are led out in substantially the same direction, and the lower battery exterior members 107 are stacked in close contact with each other. The positive terminals 104" In addition to sonic welding, the negative terminals 105 ″ are ultrasonically welded at the joint portion 105a ″.

  Thus, in the present embodiment, in the assembled battery 20 ″ configured by connecting a plurality of secondary batteries 10a ″ and 10b ″ in parallel, the electrode terminals 104 ″ and 105 ″ of the secondary batteries 10a ″ and 10b ″ are connected to each other. By increasing the thickness of the joining portions 104a "and 105a" for joining the electrodes, it is possible to prevent the electrode terminals 104 "and 105" from being deformed or distorted during joining. Yes.

  In the assembled battery 20 ″ according to the present embodiment, both main surfaces of the electrode terminals 104 ″ and 105 ″ are substantially parallel at the joint portions 104a ″ and 105a ″ of the electrode terminals 104 ″ and 105 ″. In this case, the bonding portions 104a "and 105a" are substantially parallel to the vibration direction of the horn H during ultrasonic welding, so that a strong bonding strength can be ensured. It has become.

  FIG. 13 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the third embodiment of the present invention in series.

  The assembled battery 30 ″ shown in FIG. 13 is an assembled battery formed by connecting three secondary batteries 10a ″ to 10c ″ in series, like the assembled battery 30 according to the first embodiment, and is adjacent to the secondary battery. The different-polarity terminals 105 "and 104" of the batteries 10a "to 10c" are electrically connected by ultrasonic welding at the joint portions 105a "and 104a".

  As described above, in this embodiment, in the assembled battery 30 ″ configured by connecting a plurality of secondary batteries 10a ″ to 10c ″ in series, the electrode terminals 104 ″ and 105 ″ of the secondary batteries 10a ″ and 10b ″ are connected to each other. By increasing the thickness of the joining portions 104a "and 105a" for joining the electrodes, it is possible to prevent the electrode terminals 104 "and 105" from being deformed or distorted during joining. Yes.

  Further, in the assembled battery 30 ″ according to the present embodiment, in the joint portions 104a ″ and 105a ″ of the electrode terminals 104 ″ and 105 ″, both main surfaces of the electrode terminals 104 ″ and 105 ″ are substantially parallel to each other. In this case, the bonding portions 104a "and 105a" are substantially parallel to the vibration direction of the horn H during ultrasonic welding, so that a strong bonding strength can be ensured. It has become.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, the battery pack in which two secondary batteries are connected in parallel and the battery pack in which three secondary batteries are connected in series have been described as examples, but the battery pack in the present invention is configured. The number of secondary batteries and their connection method are not particularly limited to this, and can be arbitrarily set according to the desired voltage and capacity.

FIG. 1 is a plan view of the entire secondary battery according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the secondary battery taken along line II-II in FIG. FIG. 3 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the first embodiment of the present invention in parallel. FIG. 4 is a schematic view of ultrasonic welding for joining the electrode terminals of the secondary battery in the first embodiment of the present invention. FIG. 5 is a side view showing an example of an assembled battery configured by connecting the secondary batteries according to the first embodiment of the present invention in series. FIG. 6 is an enlarged plan view of a terminal lead-out portion of the secondary battery according to the second embodiment of the present invention. 7 is a cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the second embodiment of the present invention in parallel. FIG. 9 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the second embodiment of the present invention in series. FIG. 10 is an enlarged plan view of a terminal lead-out portion of the secondary battery according to the third embodiment of the present invention. 11 is a cross-sectional view taken along line XI-XI in FIG. FIG. 12 is a side view showing an example of an assembled battery configured by connecting secondary batteries according to the third embodiment of the present invention in parallel. FIG. 13: is a side view which shows an example of the assembled battery comprised by connecting in series the secondary battery which concerns on 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Secondary battery 101 ... Positive electrode plate 101a ... Positive electrode side collector 101b, 101c ... Positive electrode layer 102 ... Separator 103 ... Negative electrode plate 103a ... Negative electrode side collector 103b, 103c ... Negative electrode layer 104 ... Positive electrode terminal 104a ... Tip part (Joint part)
104b ... sealed portion 104c ... slope 105 ... negative electrode terminal 105a ... tip portion (joint portion)
105b ... sealed portion 105c ... slope 106 ... upper exterior member 107 ... lower exterior member 108 ... power generation element 20 ... assembled battery 30 ... assembled battery H ... horn D ... receiving jig

Claims (8)

The electrode plate laminated via the separator is housed and sealed in the exterior member, and the electrode terminal connected to the electrode plate is a secondary battery derived from the outer periphery of the exterior member,
The electrode terminal is a secondary battery in which the thickness of the tip portion on the side leading out from the exterior member is relatively thicker than the thickness of the sealed portion sealed by the exterior member. . The electrode plate laminated via the separator is housed and sealed in an exterior member, and a plurality of secondary batteries in which electrode terminals connected to the electrode plate are led out from the outer periphery of the exterior member are provided,
The assembled battery in which the plurality of secondary batteries are electrically connected by joining the electrode terminals of each of the secondary batteries,
The electrode terminals of each of the secondary batteries have a relative thickness with respect to the thickness of the sealed part sealed by the exterior member. Battery pack is formed thick.   3. The assembled battery according to claim 2, wherein the electrode terminals of each of the secondary batteries are formed such that the thickness of the electrode terminals increases discontinuously from the sealing portion toward the joining portion.   4. The assembled battery according to claim 3, wherein the electrode terminals of each of the secondary batteries are formed such that the thickness of the electrode terminals increases stepwise from the sealing portion toward the joint portion. 5.   The assembled battery according to claim 2, wherein the electrode terminals of each of the secondary batteries are formed such that the thickness of the electrode terminals continuously increases from the sealing portion toward the joining portion. The electrode terminal that each of the secondary batteries has has an inclined surface that is inclined from the sealing portion toward the joining portion,
The plurality of secondary batteries are electrically connected by overlapping and joining the slopes of the electrode terminals in a state in which the adjacent secondary batteries are turned upside down. Battery pack.   The assembled battery according to any one of claims 2 to 5, wherein the electrode terminal is formed so that both main surfaces of the electrode terminal are substantially parallel at the joint portion.   The width of the electrode terminal is narrowed from the sealing portion toward the joint portion so that a cross-sectional area of the electrode terminal with respect to the derivation direction is substantially constant over the derivation direction. Item 8. The assembled battery according to any one of Items 2 to 7.

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