JP4852882B2 - Secondary battery and method for manufacturing secondary battery - Google Patents

Description

  The present invention accommodates and seals an electrode plate laminated via a separator inside an exterior member, and manufactures a secondary battery in which an electrode terminal connected to the electrode plate is led out from the exterior member and the secondary battery Regarding the method.

  The exterior member made of a sheet-like member is heat-sealed along the outer peripheral edge thereof to accommodate and seal the electrode plate, and the electrode terminals connected to the electrode plate are led out from the outer peripheral edge of the exterior member. As a thin secondary battery, a battery that employs a so-called “both cup structure” in which upper and lower sheet-like members are formed into a cup shape in order to eliminate the distinction between the front and the back has been conventionally known (for example, Patent Documents). 1).

When a thin secondary battery is stacked and the electrode terminals are connected to form an assembled battery, the electrode terminals need to be led out from a certain position in the thickness direction of the secondary battery. However, in the secondary battery adopting the both-cup structure as described above, there are cases where the accuracy of the lead-out position cannot be sufficiently ensured.
JP 2002-252145 A

An object of the present invention is to provide a secondary battery capable of accurately deriving an electrode terminal from a predetermined position.
In order to achieve the above object, according to the present invention, an electrode laminate formed by laminating a plurality of electrode plates having electrode layers formed on the main surface of a current collector with a separator interposed therebetween, and the electrode laminate A plate-like electrode terminal in which a current collector for housing and sealing the current collector and a current collector of the plurality of stacked electrode plates are connected to each other at a connection portion and are led out from an outer peripheral edge of the exterior member When, wherein the current collector having the each electrode plate, prior to SL and the electrode layer collector portion is formed, not before Symbol electrode layer is formed, connected with the connection portion to the electrode terminal A lead portion is connected to the electrode terminal in a state where one set of the lead portions is stretched, and the other lead portion is connected to the electrode terminal in a relaxed state, The set of lead portions connected to the electrode terminal in the stretched state is centered on the electrode terminal. Te located at symmetrical positions, and length is provided a secondary battery, which is a substantially identical.
In order to achieve the above object, according to the present invention, an electrode laminate formed by laminating a plurality of electrode plates, each having an electrode layer formed on a main surface of a current collector, with a separator interposed therebetween, and the electrode An exterior member that houses and seals the laminated body and a current collector of the plurality of laminated electrode plates are connected at a connection portion, and is a plate-like shape that is led out from the outer peripheral edge of the exterior member An electrode terminal, and the current collector included in each of the electrode plates is connected to the current collector portion where the electrode layer is formed and the electrode layer is not formed, and is connected to the electrode terminal at the connection portion The lead portion is divided into a tension portion connected to the electrode terminal in a stretched state and a relaxation portion connected to the electrode terminal in a relaxed state, and the tension portion secondary battery, characterized in that it is connected the relaxed portion and each of said electrode terminals and It is provided.

In the present invention, among the lead portions, one set of lead portions is connected to the electrode terminals in a stretched state, and the other lead portions are connected to the electrode terminals in a relaxed state, and connected to the electrode terminals in a stretched state. Since the set of lead portions are in symmetrical positions with the electrode terminal as the center and the length is substantially the same, the lead position of the electrode terminal can be regulated accurately and at the time of vibration input Even if the tension part is cut off, the electrical connection is secured by the relaxation part, and disconnection can be prevented.

In the present invention, the lead portion has a tension portion connected to the electrode terminal in a stretched state, and a relaxed portion connected to the electrode terminal in a relaxed state connected to the electrode terminal. Since it is divided into the tension part and the relaxation part and connected to the electrode terminal, the lead-out position of the electrode terminal can be regulated with high accuracy, and even if the tension part is cut off during vibration input, etc. Electrical connection is ensured by the portion, and disconnection can be prevented.

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

[First Embodiment]
1 is a plan view showing the entire thin battery according to the first embodiment of the present invention, FIG. 2 is a partial sectional view taken along line II-II in FIG. 1, and FIG. 3 is an electrode terminal of the thin battery shown in FIG. FIG. 4 is a partial cross-sectional view showing the tension / relaxation state of the lead portion of each current collector in the first embodiment of the present invention, and FIG. 5 is a manufacturing of a thin battery according to the first embodiment of the present invention. It is a figure which shows a method.

  1 to 4 show one thin battery 10 (unit battery), and an assembled battery having a desired voltage and capacity is formed by stacking a plurality of thin batteries 10.

  The thin battery 10 according to the first embodiment of the present invention is a lithium-based thin secondary battery. As shown in FIGS. 1 to 4, the thin battery 10 includes a plurality of positive plates 101 and negative plates 103, a separator 102 interposed therebetween, a positive terminal 104, a negative terminal 105, and an upper portion. It is comprised from the exterior member 106, the lower exterior member 107, and the electrolyte which is not specifically shown. In the present embodiment, a laminated body in which the positive electrode plate 101 and the negative electrode plate 102 are laminated via the separator 102 is referred to as an electrode laminated body 109.

  As shown in FIG. 4, the positive electrode plate 101 includes a positive electrode current collector 111 extending to the positive electrode terminal 104, and positive electrode layers 112 formed on both main surfaces of a part of the positive electrode current collector 111, 112.

  The positive electrode side current collector 111 is made of an electrochemically stable metal foil such as an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil. Further, in this positive electrode side current collector 111, the current collector 111a in which the positive electrode layer 112 is formed on both main surfaces and the positive electrode layer 112 are not formed, and are joined to the positive electrode terminal 104 by the welded portion 104a. Lead portion 111b.

The positive electrode layer 112 is obtained by mixing a positive electrode active material, a conductive agent such as carbon black, and an adhesive such as an aqueous dispersion of polytetrafluoroethylene with a current collector part of the positive electrode current collector 111. It is formed by applying to both main surfaces of 111a, drying and rolling. Examples of the positive electrode active material include lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and lithium cobaltate (LiCoO ₂ ), and chalcogen (S, Se, Te) compounds. Etc. can be mentioned.

  As shown in FIG. 4, the negative electrode plate 103 includes a negative electrode side current collector 113 extending to the negative electrode terminal 105, and negative electrode layers 114 formed on both main surfaces of a part of the negative electrode side current collector 113, 114.

  The negative electrode side current collector 113 is made of an electrochemically stable metal foil such as a nickel foil, a copper foil, a stainless steel foil, or an iron foil. Further, the negative electrode side current collector 113 is not particularly shown, but the current collector part in which the negative electrode layer 114 is formed on both main surfaces and the negative electrode layer 114 are not formed, and the negative electrode terminal 105 is welded to And a joined lead part.

  The negative electrode layer 114 is mixed with an aqueous dispersion of a styrene butadiene rubber resin powder as a precursor of an organic fired body, mixed with the negative electrode active material that absorbs and releases lithium ions of the positive electrode active material, and then pulverized. In this case, the main material is carbonized styrene butadiene rubber supported on the surface of the carbon particles, and a binder such as an acrylic resin emulsion is further mixed therewith, and this mixture is added to the current collector portion of the negative current collector 113. It is formed by applying to both main surfaces, drying and rolling. Specific examples of the negative electrode active material include amorphous carbon, non-graphitizable carbon, graphitizable carbon, and graphite.

  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 prevents a short circuit between the positive electrode plate 101 and the negative electrode plate 103 and may have a function of holding an electrolyte. The separator 102 is a microporous film made of a 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, thereby blocking the current. It also has a function.

  The separator in 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 or the like. I can do it. Thus, by forming the separator in multiple layers, various functions such as an overcurrent prevention function, an electrolyte holding function, and a separator shape maintenance (stiffness improvement) function can be provided.

  A plurality of positive plates 101 and negative plates 103 are alternately stacked via separators 102 to form an electrode stack 109. Each positive electrode plate 101 is connected to the positive electrode terminal 104 via the lead portion 111 b of the positive electrode side current collector 111 by a welded portion 104 a, while each negative electrode plate 103 is connected to the negative electrode side current collector 113. The welded part is connected to the negative electrode terminal 105 through the part.

  In addition, the number of positive electrode plates, separators, and negative electrode plates constituting the electrode laminate can be arbitrarily set as necessary. For example, one positive electrode plate, one separator, and one sheet The negative electrode plate can also constitute an electrode laminate.

  The positive electrode terminal 104 is a plate-like member made of an electrochemically stable metal material. The material constituting the positive electrode terminal 104 is not particularly limited, and can include, for example, an aluminum foil, an aluminum alloy foil, a copper foil, or a nickel foil, as with the positive electrode side current collector 111 described above. .

  In the present embodiment, as shown in FIG. 4, the lead portions 111b of the positive electrode side current collector 111 of each positive electrode plate 101 are welded to the main surfaces of the positive electrode terminals 104 by a technique such as welding. Are joined together.

  Hereinafter, a group composed of the positive electrode current collector 111 having the lead portion 111b connected to the upper main surface of the positive electrode terminal 104 is referred to as a first positive electrode current collector group 11a. A group composed of the positive current collector 111 having the lead portion 111b connected to the main surface on the side is referred to as a second positive current collector group 11b.

In the present embodiment, the lengths of the lead portions 111b of the positive current collector 111 located in the upper, middle, and lower stages in FIG. ₁ , L _2, and L ₃ , and the distance from the end of the current collector 111 a of the positive current collector 111 to the welded portion 104 a will be described as D ₁ , D _2, and D ₃ , respectively. Similarly, in the second positive electrode side current collector group 11b, the lengths of the lead portions 111b of the positive electrode side current collector 111 located in the upper, middle, and lower stages in FIG. 4 are respectively L ₄ and L _5. and while described as _{L 6,} illustrating the distance from the end of the current collector 111a of the positive electrode side current collector 111 to the weld 104a as _D 4, _{D 5} and _{D 6,} respectively.

  In the present embodiment, the positive electrode current collectors 111 constituting the first positive electrode side current collector group 11a and the positive electrodes at symmetrical positions around the positive electrode terminal 104 in the second positive electrode side current collector group 11b. The length of each lead portion 111b is substantially the same as that of the side current collector 111. In this way, by making the lengths of the lead portions 111b of the upper and lower positive electrode side current collectors 111 at symmetrical positions substantially the same, the lead position of the positive electrode terminal 104 in the thickness direction of the thin battery 10 is regulated. Is done. In addition, each positive electrode side current collector 111 constituting the first positive electrode side current collector group 11a corresponds to the first current collector in the claims, and the second positive electrode side current collector group 11b is Each of the positive electrode side current collectors 111 constituting the device corresponds to the second current collector in the claims.

More specifically, as shown in FIG. 4, the length L ₁ of the lead portion 111b of the positive electrode current collector 111 located on the outermost side in the first positive electrode current collector group 11a, Te length L ₆ of the lead portion 111b of the outermost positive electrode side current collector 111 in a symmetrical position in the second positive electrode side current collector group 11b, but have substantially the same (L ₁ = L _6).

Similarly, the length L ₂ (not shown) of the lead portion 111b of the positive electrode current collector 111 located in the middle stage in the first positive electrode current collector group 11a and the second positive electrode side current collector with respect thereto The length L ₅ (not shown) of the lead portion 111c of the middle positive electrode side current collector 111 located at a symmetrical position in the electric body group 11b is substantially the same (L ₂ = L ₅ ).

Further, the length L ₃ (not shown) of the lead portion 111b of the positive electrode current collector 111 located on the innermost side in the first positive electrode current collector group 11a, and the second positive electrode side current collector with respect to the length L ₃ (not shown). The length L ₄ (not shown) of the lead portion 111b of the innermost positive electrode current collector 111 at a symmetrical position in the electric body 111b is substantially the same (L ₃ = L ₄ ).

  Moreover, in this embodiment, the length of the lead part 111b of each positive electrode side current collector 111 of the first and second positive electrode side current collector groups 11a and 11b is equal to the current collector part of the positive electrode side current collector 111. It is substantially the same as the distance from the end of 111a to the welded portion 104a. Thereby, since the lead portion 111b is in a stretched state, the lead-out position of the positive electrode terminal 104 is regulated. Further, since the length of the lead portion 111b of the positive current collector 111 is shortened by the tension of the lead portion 111b, the electrical resistance can be reduced.

More specifically, as shown in FIG. 4, the length L ₁ of the lead portion 111b of the positive electrode side current collector 111 located on the outermost side in the first positive electrode side current collector group 11a is the positive electrode side. are substantially the same as the distance _{D 1} of the up weld 104a from the end of the current collecting part 111a of the side collector _{111 (L 1 = D 1)} . Similarly, although not particularly illustrated, the lengths L _{2 to} L ₆ of the lead portions 111b of the other positive electrode side current collector 111 are from the end of the current collector portion 111a of the positive electrode side current collector 111 to the weld portion 104a. Distances D _{2 to} D ₆ are substantially the same (L ₂ = D ₂ ,..., L ₆ = D ₆ ).

  The negative electrode terminal 105 is a plate-like member made of an electrochemically stable metal material. Although it does not specifically limit as a material which comprises this negative electrode terminal 105, Nickel foil, copper foil, stainless steel foil, or iron foil etc. can be mentioned similarly to the above-mentioned negative electrode side collector 113, for example. The lead portions of the negative electrode current collector 113 of each negative electrode plate 103 are also joined to both main surfaces of the negative electrode terminal 105 by a technique such as welding.

  Although not particularly illustrated, in the same manner as the positive electrode plate 101 described above, the negative electrode current collector 113 constituting the first negative electrode current collector group and the negative electrode terminal 105 in the second negative electrode current collector group. The length of each lead part is substantially the same as that of the negative electrode current collector 113 in a symmetrical position with respect to the center. Thus, by making the lengths of the lead portions of the upper and lower negative electrode side current collectors 113 at the symmetrical positions the same, the lead-out position of the negative electrode terminal 105 in the thickness direction of the thin battery 10 is regulated.

  Further, in this embodiment, although not particularly illustrated, the length of the lead portion of each negative electrode side current collector 113 of the first and second negative electrode side current collector groups is similar to that of the positive electrode plate 101 described above. The distance from the end of the current collector of the negative electrode current collector 1113 to the weld is substantially the same. Thereby, since the lead portion is in a stretched state, the lead-out position of the negative electrode terminal 105 in the thickness direction of the thin battery 10 is restricted. In addition, since the length of the lead portion of the negative electrode current collector 113 is shortened by the tension of the lead portion, electrical resistance can be reduced.

  In the present embodiment, the metal foil itself constituting the current collectors 111 and 113 is extended to the electrode terminals 104 and 105 to form the lead portion. However, the present invention is not particularly limited to this, and the current collector is not limited thereto. You may comprise a lead part by a member different from the metal foil which comprises the electrical conductors 111 and 113. FIG.

  As shown in FIGS. 1 and 2, each of the upper exterior member 106 and the lower exterior member 107 is composed of a sheet-like member such as a resin-metal thin film laminate material formed into a cup shape. This sheet-like member is configured by laminating three layers of an inner resin layer, a metal layer, and an outer resin layer from the inside to the outside of the thin battery 10.

  The inner resin layer that constitutes the sheet-like member is made of a resin film having excellent electrolytic solution resistance and heat fusion properties, such as polyethylene, modified polyethylene, polypropylene, modified polypropylene, or ionomer. The metal layer is made of a metal foil such as aluminum. The outer resin layer is made of, for example, a resin film excellent in electrical insulation, such as a polyamide resin or a polyester resin.

  Further, in the present embodiment, as shown in FIG. 2, in order to maintain the sealing performance inside the thin battery 10, a seal film 108 is provided at a portion where the electrode terminals 104 and 105 and the exterior members 106 and 107 are in contact with each other. Intervene. The seal film 108 is made of, for example, polyethylene or polypropylene. The sealing film 108 may be made of the same system as the synthetic resin material constituting the inner resin layer of the exterior members 106 and 107 in both the positive electrode terminal 104 and the negative electrode terminal 105. To preferred.

  These exterior members 106 and 107 enclose the electrode laminate 109, part of the positive electrode terminal 104, and part of the negative electrode terminal 105 described above, and the organic liquid solvent is formed in the space formed by the exterior members 106 and 107. While injecting a liquid electrolyte made into a solute with a lithium salt such as lithium perchlorate, lithium borofluoride, or lithium hexafluorophosphate into the vacant space, the outer peripheral edges of the exterior members 106 and 107 are heated. Heat fusion by pressing. Thereby, a part of the electrode laminate 109 and the electrode terminals 104 and 105 are accommodated in the exterior members 106 and 107 and sealed.

  Examples of the organic liquid solvent include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate. The organic liquid solvent of the present invention is not limited to this, and an organic liquid solvent prepared by mixing and preparing an ether solvent such as γ-butylactone (γ-BL) or dietoshietane (DEE) in an ester solvent. It can also be used.

  At the time of this heat fusion, in this embodiment, as shown in FIG. 5, the positive terminal 104 to which each positive current collector 111 is connected to both main surfaces is connected to the lead-out direction of the terminal 104 (X in FIG. 5). The heat seal bar HS positioned above and below is moved in the Y direction in FIG. 5 to press the exterior members 106 and 107, and the exterior members 106 and 107 are connected to the positive terminal. Thermally fused to 104.

  Similarly, although not particularly illustrated, the negative electrode terminal 105 in which the respective negative electrode side current collectors 113 are connected to both main surfaces is also pulled in the lead-out direction of the terminal 105, and the exterior members 106 and 107 are attached in a state where tension is applied. It is heat-sealed to the negative electrode terminal 105.

  As described above, in the present embodiment, the lead portion 111 b of the positive electrode side current collector 111 is connected to both main surfaces of the positive electrode terminal 104. Since the lead-out position of the positive electrode terminal 104 in the thickness direction of the thin battery 10 is regulated by the positive electrode side current collector 111 connected to both the main surfaces, the positive electrode terminal 104 can be led out from the predetermined position with high accuracy. It becomes.

  Similarly, in the present embodiment, the lead portion of the negative electrode current collector 113 is connected to both main surfaces of the negative electrode terminal 105. The current collector 113 connected to both the main surfaces regulates the lead-out position of the negative electrode terminal 105 in the thickness direction of the thin battery 10, so that the negative electrode terminal 105 can be led out from the predetermined position with high accuracy. .

  In the present embodiment, the lead portions of the current collectors 111 and 113 are connected to both main surfaces of the electrode terminals 104 and 105, so that the corner portions of the electrode terminals 104 and 105 and the exterior members 106 and 107 are interposed. Since the lead portion is interposed, it is possible to prevent the exterior members 106 and 107 from being damaged by the corner portions of the electrode terminals 104 and 105.

[Second Embodiment]
FIG. 6 is a partial cross-sectional view showing the tension / relaxation state of the lead portion of each current collector in the second embodiment of the present invention.

  The thin battery according to the second embodiment of the present invention is different from the thin battery 10 according to the first embodiment described above in the tension / relaxation state of the lead portion of the current collector. The thin battery 10 is the same. Only the differences between the thin battery according to the second embodiment and the thin battery 10 according to the first embodiment will be described below.

  Also in this embodiment, as shown in FIG. 6, the lead portions 111 b of the positive current collector 111 of each positive electrode plate 101 are formed on both main surfaces of the positive electrode terminal 104 by a welding method or the like, for example. It is joined.

In the present embodiment, as in the first embodiment, in the first positive electrode current collector group 11a, the lead of the positive electrode current collector 111 located in the upper, middle, and lower stages in FIG. The length of the portion 111b will be described as L ₁ , L ₂ and L ₃ , respectively, and the distance from the end of the current collecting portion 111a of the positive current collector 111 to the welded portion 104a will be D ₁ , D ₂ and It described as D _3. Similarly, in the second positive electrode side current collector group 11b, the lengths of the lead portions 111b of the positive electrode side current collector 111 located in the upper, middle, and lower stages in FIG. 6 are set to L ₄ and L ₅ , respectively. and while described as _{L 6,} illustrating the distance from the end of the current collecting part 111a of the positive electrode side current collector 111 to the weld 104a as _D 4, _{D 5} and _{D 6,} respectively.

In the present embodiment, the length L ₁ (not shown) of the lead portion 111b of the positive electrode current collector 111 located on the outermost side in the first positive electrode current collector group 11a is the positive electrode current collector. The distance D ₁ (not shown) from the end of the current collector 111a to the welded portion 104a is substantially the same (L ₁ = D ₁ ).

Similarly, in the second positive electrode current collector group 11b, the length L ₆ (not shown) of the lead portion 111b of the positive electrode current collector 111 located on the outermost side is the positive electrode current collector. The distance D ₆ (not shown) from the end of the current collector 111a to the welded portion 104a is substantially the same (L ₆ = D ₆ ). The length L ₆ is substantially the same as the length L ₁ described above (L ₁ = L ₆ ), thereby restricting the lead-out position of the positive electrode terminal 104.

In contrast, the length L ₂ of the lead portion 111b of the first positive electrode side current collector is positioned in the middle in the group 11a positive side current collector 111, the collector portions 111a of the positive electrode side current collector 111 is longer than the distance _{D 2} to the weld 104a from an end portion _{(L 2> D} 2).

Similarly, the length L ₃ (not shown) of the lead portion 111b of the positive electrode side current collector 111 located on the innermost side in the first positive electrode side current collector group 11a is also the same as that of the positive electrode side current collector 111. The distance D ₃ (not shown) from the end of the current collector 111a to the welded portion 104a is longer (L ₃ > D ₃ ).

Also in the second positive electrode current collector group 11b, the length L ₄ (not shown) of the lead portion 111b of the positive electrode current collector 111 located on the innermost side is the positive electrode current collector 111. The distance D ₄ (not shown) from the end of the current collector 111a to the weld 104a is longer (L ₄ > D ₄ ).

Similarly, the length L ₅ (not shown) of the lead portion 111b of the positive electrode current collector 111 located in the middle stage in the second positive electrode current collector group 11b is also the current collector of the positive electrode current collector 111. It is longer than the distance D ₅ (not shown) from the end of the electric part 111a to the welded part 104a (L ₅ > D ₅ ).

  Therefore, in the present embodiment, only the lead portion 111b of the positive electrode current collector 111 located on the outermost side in each of the first and second positive electrode current collector groups 11a and 11b is stretched. Only the lead part 111 b contributes to the regulation of the lead-out position of the positive electrode terminal 104.

  In this way, only the lead portions 111b of some of the positive current collectors 111 are stretched, and the lead portions 111b of other positive current collectors 111 are loosened, so that when vibration is input, etc. It is possible to prevent all the lead portions 111b from being cut and disconnected.

  Although not specifically shown, in the first and second negative electrode current collector groups, similarly, only the lead portion of the negative electrode current collector 113 located on the outermost side is stretched. The lead portions of the negative electrode side current collector 113 other than those are loosened.

  When manufacturing the thin battery 10 according to this embodiment, the length of the lead portions 111b of all the positive electrode current collectors 111 is positioned on the outermost side with the positive electrode terminal 104 as the center. Each positive electrode plate 101 is joined to the positive electrode terminal 104 by the welded portion 104a with the length of the lead portions 111b of 111 and the end portions of all the lead portions 111b aligned.

  Thereby, since the positive electrode side current collector 111 located in the middle stage and the innermost side is automatically loosened at the time of joining, the thin battery according to the present embodiment can be easily manufactured. In addition, since all the positive electrode side current collectors 111 have the same length, it is possible to share the components constituting the thin battery.

  Similarly, the length of the lead part of the negative electrode side current collector 113 of all the negative electrode plates 103 is set to the length of the lead part of the negative electrode side current collector 113 which is located on the outermost side with respect to the negative electrode terminal 105. In addition, each negative electrode plate 103 is joined to the negative electrode terminal 105 with the end portions of all the lead portions 111b being aligned. Next, as in the first embodiment, the exterior members 106 and 107 are heat-sealed to the electrode terminals 104 and 105 while pulling the electrode terminals 104 and 105 in the lead-out direction.

  As described above, in this embodiment, the lead-out position of the positive electrode terminal 104 can be regulated by connecting the lead portions 111 b of the positive electrode side current collector 111 to both main surfaces of the positive electrode terminal 104. Similarly, the lead-out position of the negative electrode terminal 105 can be regulated by connecting the lead portions of the negative electrode side current collector 113 to both main surfaces of the negative electrode terminal 105.

  In the present embodiment, the lead portions of the current collectors 111 and 113 are connected to both main surfaces of the electrode terminals 104 and 105, thereby preventing the exterior members 106 and 107 from being damaged by the corner portions of the electrode terminals 104 and 105. I can do it.

  Further, in the present embodiment, the lead portions of some of the current collectors 111 and 113 are connected to the electrode terminals 104 and 105 while the lead portions of the current collectors 111 and 113 are stretched, and the lead portions of the remaining current collectors 111 and 113 are loosened. By connecting to the electrode terminals 104 and 105, disconnection at the time of vibration input or the like can be prevented.

[Third Embodiment]
7 is a partial cross-sectional view showing a thin battery according to a third embodiment of the present invention, FIG. 8 is a plan view around the electrode terminals of the thin battery shown in FIG. 7, and FIG. 9A is taken along the line IXA-IXA in FIG. FIG. 9B is a partial cross-sectional view showing the tension / relaxation state of each lead portion along the line IXB-IXB in FIG. 8.

  The thin battery 10 ′ according to the third embodiment of the present invention is different from the thin battery 10 according to the first embodiment in that the lead portion of the current collector has a tension portion and a relaxation portion, and these are divided. Other than that, the rest is the same as the thin battery 10 according to the first embodiment. Only the differences between the thin battery 10 'according to the third embodiment and the thin battery 10 according to the first embodiment will be described below.

  In the thin battery 10 ′ according to the present embodiment, as shown in FIGS. 7 to 9B, the lead portions 111b of the positive electrode side current collector 111 of each positive electrode plate 101 have tension portions 111c positioned at both ends, and a central portion. And the slack portion 111d sandwiched between the tension portions 111c, and the tension portion 111c and the slack portion 111d are connected to the positive electrode terminal 104 at the weld portion 104a by a technique such as welding. It is joined to both main surfaces.

In this embodiment, among the first positive electrode side current collector group 11a, the lengths of the tension portions 111c of the positive electrode side current collector 111 located in the upper, middle, and lower stages in FIG. The distances from the end of the current collector 111a of the positive current collector 111 to the welded portion 104a will be described as D _a1 , D _a2, and D _a3 , respectively, as _a1 , L _a2, and _La3 . Similarly, in the second positive electrode side current collector group 11b, the lengths of the tension portions 111c of the positive electrode side current collector 111 located in the upper, middle, and lower stages in FIG. 9A are respectively represented by L _a4 and L _a5. and while described as _{L a6,} illustrating the distance from the end of the current collecting part 111a of the positive electrode side current collector 111 to the weld 104a as _{D a4, D a5} and _{D a6,} respectively.

On the other hand, among the first positive electrode side current collector 11a, the lengths of the relaxed portions 111d of the positive electrode side current collector 111 located in the upper, middle, and lower stages in FIG. 9B are respectively represented by L _b1 and L _b2. And L _b3 , and the distances from the end of the current collector 111 a of the positive current collector 111 to the welded portion 104 a will be described as D _b1 , D _b2, and D _b3 , respectively. Similarly, in the second positive electrode side current collector group 11b, the lengths of the relaxed portions 111d of the positive electrode side current collector 111 located in the upper, middle, and lower stages in FIG. 9B are respectively _expressed as L _b4 and L _b5. and while described as _{L b6,} illustrating the distance from the end of the current collecting part 111a of the positive electrode side current collector 111 to the weld 104a as _{D b4, D b5} and _{D b6,} respectively.

As shown in FIG. 9A, the tension portion 111c of the lead portion 111b of each positive electrode side current collector 111 is a distance D _{a1 to} D from the end of the current collector portion 111a of the positive electrode current collector 111 to the welded portion 104a. _a6 and each have substantially the same length _{L a1 ~L a6 (L a1 =} D a1, ···, L a6 = D a1). Thereby, since the tension | tensile_strength part 111c is in the state always tensioned, the derivation | leading-out position of the positive electrode terminal 104 is controlled. The tension portions 111c of the respective positive electrode side current collectors 111 constituting the first positive electrode side current collector group 11a and the second positive electrode side current collector group 11b are symmetric with respect to the positive electrode terminal 104. Each of the tension portions 111c of the positive electrode side current collector 111 has substantially the same length (L _a1 = L _a6 , L _a2 = L _a5 , L _a3 = L _a4 ). Thereby, the lead-out position of the positive electrode terminal 104 in the thickness direction of the thin battery 10 is regulated by the upper and lower tension portions 111c at the symmetrical positions.

On the other hand, as shown in FIG. 9B, the relaxed portion 111d of the lead portion 111 of each positive electrode side current collector 111 is a distance from the end of the current collector portion 111a of the positive electrode side current collector 111 to the weld portion 104a. It has lengths L _{b1 to} L _b6 longer than D _{b1 to} D _b6 (L _b1 > D _b1 ,..., L _b6 > D _b6 ). As a result, the relaxed portion 111d is always in a relaxed state. Therefore, even if the tensioned portion 111c is cut off during vibration input or the like, electrical connection is secured by the relaxed portion 111d, and disconnection is prevented.

  Similarly, although not particularly illustrated, the lead portion of the negative electrode side current collector 113 of each negative electrode plate 103 is also divided into a tensioned portion 111c in a tensioned state and a relaxed portion 11d in a relaxed state. Has been.

  As described above, in this embodiment, the lead-out position of the positive electrode terminal 104 can be regulated by joining the lead portion 111 of the positive electrode side current collector 111 to both main surfaces of the positive electrode terminal 104. Similarly, the lead-out position of the negative electrode terminal 105 can be regulated by connecting the lead portions of the negative electrode side current collector 113 to both main surfaces of the negative electrode terminal 105.

  In the present embodiment, the lead portions of the current collectors 111 and 113 are connected to both main surfaces of the electrode terminals 104 and 105, thereby preventing the exterior members 106 and 107 from being damaged by the corner portions of the electrode terminals 104 and 105. I can do it.

  Further, in the present embodiment, the lead portions of the current collectors 111 and 113 are connected to the electrode terminals 104 and 105 in a state where the lead portions are stretched, and the electrode terminals 104 and 105 in a state where the loose portions of the lead portions are loosened. By connecting to, disconnection at the time of vibration input can be prevented.

[Fourth Embodiment]
FIG. 10A is a partial cross-sectional view showing the tension / relaxation state of each lead portion along the line corresponding to the IXA-IXA line of FIG. 8 in the thin battery according to the fourth embodiment of the present invention, and FIG. FIG. 9 is a partial cross-sectional view showing a tension / relaxation state of each lead portion along a line corresponding to the line IXB-IXB in FIG. 8 in the thin battery according to the fourth embodiment.

  In the thin battery according to the fourth embodiment of the present invention, only the lead portions of the current collectors 111 and 113 located on the outermost side are divided into a tension portion and a relaxation portion, and the other current collectors 111 are provided. , 113 are different from the thin battery 10 ′ according to the third embodiment in that they are not divided, but are otherwise the same as the thin battery 10 ′ according to the third embodiment. Only the difference between the thin battery according to the fourth embodiment and the thin battery 10 'according to the third embodiment will be described below.

  In the thin battery according to the present embodiment, as shown in FIGS. 10A and 10B, only the lead portion 111b of the positive electrode current collector 111 located on the outermost side in the first positive electrode current collector group 11a is strained. The lead 111b is divided into a portion 111c and a relaxed portion 111d, and the lead 111b of the positive current collector 111 located in the middle and innermost side in the first positive current collector group 11a is not divided.

In the present embodiment, among the first positive electrode side current collector group 11a, the length of the tension portion 111c of the positive electrode side current collector 111 which is located in the upper part in FIG. 9A while described as L _a1 The distance from the end of the current collector 111a of the positive current collector 111 to the weld 104a will be described as D _a1 . Also, among the first positive electrode side current collector group 11a, the length of the relaxed portion 111d of the positive electrode side current collector 111 which is located in the upper part in FIG. 9B while described as L _b1, the positive electrode side current The distance from the end of the current collector 111a of the electric body 111 to the welded portion 104a will be described as _Db1 .

On the other hand, in the first positive electrode side current collector group 11a, the lengths of the lead portions 111b of the positive electrode side current collector 111 located in the middle stage and the lower stage in FIGS. 9A and 9B are L ₂ and while it described as L _3, illustrating the distance from the end of the current collecting part 111a of the positive electrode side current collector 111 to the weld 104a as _{D 2} and _{D 3.}

As shown in FIG. 10A, the tensioned portion 111 c of the positive electrode side current collector 111 located on the outermost side in the first positive electrode side current collector group 11 a has a current collector 111 a of the positive electrode side current collector 111. It has a length L _a1 that is substantially the same as the distance D _a1 from the end portion to the welded portion 104a (L _a1 = D _a1 ). Thereby, since the tension | tensile_strength part 111c is in the state always tensioned, the derivation | leading-out position of the positive electrode terminal 104 is controlled.

On the other hand, as shown in FIG. 10B, the loosened portion 111d of the positive electrode side current collector 111 located on the outermost side in the first positive electrode side current collector group 11a is the current collector of the positive electrode side current collector 111. It has a length L _b1 longer than the distance D _b1 from the end of the electric part 111a to the welded part 104a (L _b1 > D _b1 ). As a result, the relaxed portion 111d is always in a relaxed state. Therefore, even if the tensioned portion 111c is cut off due to input of vibration or the like, electrical connection is secured by the relaxed portion 111d, and disconnection is prevented.

Moreover, the lead part 111b of the positive electrode side current collector 111 located in the middle stage and the innermost side in the first positive electrode side current collector group 11a has a single metal foil as shown in FIGS. 10A and 10B. The lengths L ₂ and L ₃ (not shown) that are longer than the distances D ₂ and D ₃ (not shown) from the end of the current collector 111a of the positive current collector 111 to the welded portion 104a. (L ₂ > D ₂ , L ₃ > D ₃ ).

  Similarly, in the second positive electrode side current collector 11b, as shown in FIGS. 10A and 10B, only the lead portion 111b of the positive electrode side current collector 111 located on the outermost side is the tension portion 111c and the relaxation portion 111d. In the second positive electrode side current collector group 11b, the lead portion 111b of the positive electrode side current collector 111 located in the middle stage and the innermost side is not divided.

  As shown in FIG. 10A, the tension portion 111c of the positive electrode current collector 111 located on the outermost side in the second positive electrode current collector group 11b is always in a tensioned state. The portion 111d is always in a slack state as shown in FIG. 10B. Further, the positive electrode side current collector 111 located in the middle and innermost side in the second positive electrode side current collector group 11b is composed of a single metal foil, as shown in FIGS. 10A and 10B. Moreover, it is always in a relaxed state.

  Therefore, in the present embodiment, only the tension portion 111c of the lead portion 111b of the positive electrode current collector 111 located on the outermost side in each of the first and second positive electrode current collector groups 11a and 11b is stretched. Only the tensioned portion 111c contributes to the regulation of the lead-out position of the positive electrode terminal 104.

  Thus, by providing the tension portion 111c only in the lead portion 111b of some of the positive electrode side current collectors 111, it is possible to prevent all the lead portions 111b from being cut and disconnected at the time of vibration input or the like.

In the present embodiment, the length L _a1 tension portion 111c of the first positive electrode side current collector group 11a on the most located outside and positive electrode collector 111, the second positive electrode side current collector The length L _a6 of the tensioned portion 111c of the positive electrode current collector 111 located on the outermost side of the group 11b is substantially the same (L _a1 = L _a6 ). Thereby, the lead-out position of the positive electrode terminal 104 in the thickness direction of the thin battery 10 is regulated by the upper and lower tension portions 111c at the symmetrical positions.

  Similarly, although not particularly illustrated, also in the first and second negative electrode side current collector groups, only the lead portion of the negative electrode side current collector 113 positioned on the outermost side is divided into a tension portion and a relaxation portion. The other lead portions of the negative electrode current collector 113 are in a loose state.

  As described above, in this embodiment, the lead-out position of the positive electrode terminal 104 can be regulated by joining the lead portion 111 of the positive electrode side current collector 111 to both main surfaces of the positive electrode terminal 104. Similarly, the lead-out position of the negative electrode terminal 105 can be regulated by connecting the lead portions of the negative electrode side current collector 113 to both main surfaces of the negative electrode terminal 105.

  In the present embodiment, the lead portions of the current collectors 111 and 113 are connected to both main surfaces of the electrode terminals 104 and 105, thereby preventing the exterior members 106 and 107 from being damaged by the corner portions of the electrode terminals 104 and 105. I can do it.

  Furthermore, in the present embodiment, the lead portions of some of the current collectors 111 and 113 are divided into the tension portions 111c and the slack portions 11d, and the electrodes are in a state where the lead portions of the remaining current collectors 111 and 113 are slackened. By connecting to the terminals 104 and 105, disconnection at the time of vibration input or the like can be prevented.

  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 second embodiment, the current collectors 111 and 113 located on the outermost side are stretched. However, the present invention is not particularly limited to this. For example, the current collector located on the innermost side is used. The current collectors 111 and 113 may be stretched and other current collectors may be loosened. Similarly, in the fourth embodiment, the current collectors 111 and 113 located on the outermost side are divided into a tension part 111c and a relaxation part 111d. However, the present invention is not particularly limited to this. For example, The current collectors 111 and 113 located on the innermost side may be divided into a tension portion 111c and a relaxation portion 111d.

FIG. 1 is a plan view showing the entire thin battery according to the first embodiment of the present invention. FIG. 2 is a partial cross-sectional view taken along the line II-II in FIG. FIG. 3 is a plan view of the periphery of the electrode terminals of the thin battery shown in FIG. FIG. 4 is a partial cross-sectional view showing the tension / relaxation state of the lead portion of each current collector in the first embodiment of the present invention. FIG. 5 is a diagram showing a method for manufacturing a thin battery according to the first embodiment of the present invention. FIG. 6 is a partial cross-sectional view showing the tension / relaxation state of the lead portion of each current collector in the second embodiment of the present invention. FIG. 7 is a partial cross-sectional view showing a thin battery according to a third embodiment of the present invention. FIG. 8 is a plan view around the electrode terminals of the thin battery shown in FIG. 9A is a partial cross-sectional view showing a tension / relaxation state of each lead portion along the line IXA-IXA in FIG. 9B is a partial cross-sectional view showing a tension / relaxation state of each lead portion along the line IXB-IXB in FIG. 10A is a partial cross-sectional view showing a tension / relaxation state of a lead portion of a current collector along a line corresponding to the IXA-IXA line of FIG. 8 in a thin battery according to the fourth embodiment of the present invention. 10B is a partial cross-sectional view showing the tension / relaxation state of the lead portion of the current collector along the line corresponding to the IXB-IXB line in FIG. 8 in the thin battery according to the fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10 '... Thin battery 101 ... Positive electrode plate 111 ... Positive electrode side collector 11a, 11b ... Positive electrode side collector group 111a ... Current collector part 111b ... Lead part 111c ... Tension part 111d ... Relaxation part 112 ... Positive electrode layer 102 ... Separator 103 ... Negative electrode plate 113 ... Negative electrode side current collector 114 ... Negative electrode layer 104 ... Positive electrode terminal 104a ... Welded portion 105 ... Negative electrode terminal 106 ... Upper exterior member 107 ... Lower exterior member 108 ... Seal film 109 ... Electrode laminate HS ... Heat seal bar

Claims (2)

An electrode laminate formed by laminating a plurality of electrode plates having electrode layers formed on the main surface of the current collector through a separator;
An exterior member that houses and seals the electrode laminate;
A current collector of the plurality of stacked electrode plates is connected at a connection portion, and is provided with plate-like electrode terminals that are led out from the outer peripheral edge of the exterior member,
The current collector of each electrode plate is:
A collector unit for pre Symbol electrode layer is formed,
Not before Symbol electrode layer is formed, has a lead portion connected with the connecting portion to the electrode terminal,
Among the lead parts, a pair of lead parts are connected to the electrode terminal in a stretched state, and the other lead parts are connected to the electrode terminal in a relaxed state,
A pair of lead portions connected to the electrode terminals in the stretched state are in symmetrical positions about the electrode terminals and have substantially the same length. An electrode laminate formed by laminating a plurality of electrode plates having electrode layers formed on the main surface of the current collector through a separator;
An exterior member that houses and seals the electrode laminate;
A current collector of the plurality of stacked electrode plates is connected at a connection portion, and is provided with plate-like electrode terminals that are led out from the outer peripheral edge of the exterior member,
The current collector of each electrode plate is:
A current collector formed with the electrode layer;
The electrode layer is not formed, and has a lead portion connected to the electrode terminal at the connection portion,
The lead portion is divided into a tension portion connected to the electrode terminal in a stretched state and a relaxation portion connected to the electrode terminal in a relaxed state, and the tension portion and the relaxation portion are respectively connected to the electrode terminal. A secondary battery characterized by being connected.

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