JP2017045710A - Flat battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, while conventional flat batteries have a structure where a positive electrode and a negative electrode are sandwiched by a thin plate-like positive electrode-side case and a thin plate-like negative electrode-side case and outer peripheries of the positive electrode-side case and the negative electrode-side case are sealed with an insulator, moisture enters from the outside through the insulator, so that the life and reliability of flat batteries are deteriorated.SOLUTION: A flat battery 1 including electrodes 20, 40 held between an upper exterior metal plate 10 and a lower exterior metal plate 50 employs a structure where the upper exterior metal plate 10 and the lower exterior metal plate 50 are bonded via a water-blocking frame body 60.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flat battery.

  In recent years, thin and lightweight information terminals such as smart phones have been widely used in the world, and flat batteries used are also required to be smaller and thinner.

  A flat battery has a positive electrode plate (hereinafter referred to as “positive electrode”) and a negative electrode plate (hereinafter referred to as “positive electrode”) in which an active material layer (a mixture of an active material and a binder) is provided on the surface of a metal foil. A negative electrode) is formed in a thin plate shape, and is opposed to each other in an electrically insulated state via a separator, and an electrolytic solution is interposed therebetween.

  Then, the positive and negative electrodes opposed to each other are accommodated in a battery case having a predetermined shape, and the positive electrode and the negative electrode are electrically connected to predetermined electrode terminals of the battery case, respectively, thereby functioning as a primary or secondary battery. The battery case is composed of a positive electrode side case and a negative electrode side case, and a structure in which the positive electrode and the negative electrode opposed to each other are accommodated in the positive electrode side case and the whole is enclosed in the negative electrode side case via an insulating material is the mainstream.

As another structure, a thin plate-like positive electrode side case and a thin plate-like negative electrode side case are sandwiched between the positive electrode and the negative electrode facing each other via a separator, and the outer periphery of the positive electrode side case and the negative electrode side case is sealed with an insulator. There is a structure. Since this structure has the advantage that the battery can be made particularly thin, there have been many proposals. (For example, Patent Document 1)
In the technique described in Patent Document 1, the positive electrode and the negative electrode facing each other are sandwiched between the positive electrode side case and the negative electrode side case, and the outer periphery of the positive electrode side case and the negative electrode side case is sealed using the thermoadhesive resin. Structure.

  The technique disclosed in Patent Document 1 will be described in detail below with reference to the drawings. 16 shows the structure of the thin battery 100 disclosed in Patent Document 1, FIG. 16 (a) is a perspective view, and FIG. 16 (b) is a sectional view. As shown in FIG. 16B, the thin battery 100 disclosed in Patent Document 1 includes a negative electrode portion 104, a positive electrode portion 106, and a separator 30 that are power generation elements between a positive electrode terminal plate 101 and a negative electrode terminal plate 101 ′. The insulating thermal adhesive resin 102 is disposed in the gap between the outer peripheral portions of the positive electrode terminal plate 101 and the negative electrode terminal plate 101 ′, and the insulating thermal adhesive resin 102 is used as the positive electrode terminal. The thin battery 100 is sealed by thermally welding the plate 101 and the negative electrode terminal plate 101 ′.

JP 63-124359 A (Claims, Fig. 2)

  In the thin battery 100 disclosed in Patent Document 1, the positive electrode terminal plate 101 and the negative electrode terminal plate 101 ′ are subjected to high-temperature treatment, and then bonded to the insulating thermal bonding resin 102, and then the positive electrode terminal plate 101 and the negative electrode terminal plate 101 ′. And the insulating surface of the insulating thermal adhesive resin 102 are strengthened.

However, since the insulating thermal adhesive resin 102 is a polymer material based on an organic material, it has a high moisture permeability. In other words, the positive electrode terminal plate 101 and the negative electrode terminal plate 101 ′ are insulated, but completely remove the moisture that enters from the insulating thermal adhesive resin 102 itself, which is an important element for sealing the thin battery 100. I can't shut it down.

  For this reason, various characteristics of the thin battery 100 are deteriorated, and further, when an adverse condition of high temperature and high humidity is applied, problems such as a decrease in capacity and a loss of basic functions as a battery occur.

  The present invention aims to solve the above problems. In other words, a highly reliable flat battery is realized by adopting a structure that reduces moisture permeability in the outer peripheral portion of the metal case containing the positive electrode and the negative electrode.

  In order to solve the above problems, the flat battery of the present invention adopts the following configuration.

  The flat battery of the present invention is a flat battery in which an electrode is sandwiched between an upper exterior metal plate and a lower exterior metal plate, and the upper exterior metal plate and the lower exterior metal plate are interposed via a water shielding frame. It is characterized by being bonded.

  As a result, moisture flowing in or permeating from the outer periphery of the flat battery is reduced, and the life and reliability of the battery is improved.

  Further, the water shielding frame may be ceramic or glass.

  Thereby, since a water-impervious frame is comprised with an insulator, the electrical insulation of an upper exterior metal plate and a lower exterior metal plate improves, and the reliability as a battery improves. Moreover, the choice of a joining method spreads in each joint surface of a water-impervious frame, an upper exterior metal plate, and a lower exterior metal plate, and flexibility is increased in designing a battery.

  Furthermore, you may arrange | position a spacer between an upper exterior metal plate or a lower exterior metal plate, and a water-impervious frame.

As a result, even when the water-impervious frame is made of an electrical conductor, the electrical insulation between the upper and lower metal plates is ensured, so the metal with the highest water-impervious frame is selected as the water-impervious frame. Thus, the battery life and reliability are improved.
Further, a rough surface is provided on one or both of at least a part of an adhesive surface for joining the upper exterior metal plate and the water-impervious frame and at least a part of an adhesive surface for joining the lower exterior metal plate and the water-impervious frame. A conversion region may be provided. A heat insulating ring may be disposed between the water-impervious frame and the electrode.

  Furthermore, one of the upper and lower exterior metal plates and the water-impervious frame may be directly coupled.

  This eliminates the need for an adhesive on the joint surface between the water-impervious frame and the upper or lower metal plate, lowers the number of joints, improves durability, and reduces the amount of moisture inflow. Improves.

  Moreover, either the upper exterior metal plate or the lower exterior metal plate and the water-impervious frame may be integrally formed.

  As a result, the inflow path of moisture from the outside is reduced by one place, and electrical insulation between the upper and lower metal plates is ensured, so that reliability is improved.

  According to the present invention, a flat battery having a long life and high reliability is realized because a structure that reduces moisture permeability at the outer periphery of the metal that houses the positive electrode and the negative electrode is employed.

It is sectional drawing and the external view which show the structure of the flat battery 1 of this invention. It is sectional drawing which shows the electrode coating process in the manufacturing process of the flat battery 1 shown in FIG. It is sectional drawing which shows the electrode coating process following FIG. 2 of the flat battery 1 shown in FIG. It is sectional drawing which shows the assembly process in the manufacturing process of the flat battery 1 shown in FIG. FIG. 5 is a cross-sectional view and an external view showing an assembly process subsequent to FIG. 4 of the flat battery 1 shown in FIG. 1. It is sectional drawing which shows the assembly process following FIG. 5 of the flat battery 1 shown in FIG. 1, and the external view of the flat battery 1 of a shape different from FIG. It is sectional drawing which shows the electrode coating process for manufacturing many flat type batteries shown in FIG. It is sectional drawing which shows the structure of the flat battery 2 of this invention. It is sectional drawing which expands and shows the structure of the flat battery 2 shown in FIG. It is sectional drawing which shows the structure of the flat battery 3 of this invention. It is sectional drawing which expands and shows the structure of the flat battery 3 shown in FIG. It is sectional drawing which shows the structure of the flat battery 4 of this invention. It is sectional drawing which shows the structure of the flat battery 5, the flat battery 6, and the flat battery 7 of this invention. It is sectional drawing which shows the structure of the flat battery 8 of this invention. It is the upper side figure and sectional drawing which show the assembly process in the manufacturing process of the flat battery 8 of this invention. It is the external view and sectional drawing which show the structure of the thin battery of a prior art example.

  Hereinafter, embodiments of the flat battery of the present invention will be described. It should be noted that some elements not related to the description are omitted, and the same elements as those in the conventional example are given the same numbers, and redundant description is omitted. In addition, in description, the description and figure are one Embodiment, Comprising: It is not limited to this. In addition, dimensions in the drawings do not reflect actual shapes and may be exaggerated in part in order to make the drawings easier to see.

  Hereinafter, a flat battery according to a first embodiment will be described with reference to the drawings.

  1 to 7 show the flat battery according to the first embodiment, FIG. 1 is a cross-sectional view and an external view showing the structure of the flat battery 1, and FIG. 2 shows the manufacturing process of the flat battery 1. FIG. 3 is a sectional view showing the electrode coating process, FIG. 3 is a sectional view showing the electrode coating process in the manufacturing process of the flat battery 1 following FIG. 2, and FIG. 4 shows the assembly process of the flat battery 1. FIG. 5 is a cross-sectional view and an external view showing the assembly process of the flat battery 1 following FIG. 4, and FIG. 6 is a cross-sectional view showing the assembly process of the flat battery 1 following FIG. FIG. 7 is an external view of a flat battery 1 having a shape different from that of FIG. 1, and FIG. 7 is a cross-sectional view showing an electrode coating process when manufacturing many flat batteries shown in FIG.

[Structure Explanation of First Embodiment: FIG. 1]
The structure of the flat battery 1 will be described with reference to FIG. FIG. 1A is a cross-sectional view showing the structure of the flat battery 1, and FIG. 1B is an external view showing the appearance of the flat battery 1. 1A is a cross-sectional view taken along the line AA ′ of FIG.

  As shown in FIG. 1B, the flat battery 1 has a thin cylindrical appearance, a diameter R of about 9 mm, and a height T of about 1.7 mm in the present embodiment. Depending on the capacity of 1, it can be selected from 0.5 mm to 3 mm.

  Next, the structure of the flat battery 1 will be described with reference to FIG. In FIG. 1A, the flat battery 1 includes a positive electrode 20 and a negative electrode 40 sandwiched between a flat upper and lower outer metal plate 10 and a lower outer metal plate 50 with a separator 30 interposed therebetween. In this structure, the outer periphery of the lower exterior metal plate 50 is sealed with a water-impervious frame 60, an adhesive layer 70u, and an adhesive layer 70d. The positive electrode 20 is fixed to the upper exterior metal plate 10 with a binder included in the positive electrode 20, and the negative electrode 40 is fixed to the lower exterior metal plate 50 with a binder included in the negative electrode 20.

  The height W of the adhesive layer 70u and the adhesive layer 70d and the height B of the water-impervious frame 60 in FIG. In the following description, a structure in which the positive electrode 20 is fixed to the upper exterior metal plate 10 is referred to as a “positive electrode side structure”, and a structure in which the negative electrode 40 is fixed to the lower exterior metal plate 50 is referred to as a “negative electrode structure”. Is written.

Hereinafter, each element of the flat battery 1 will be described in detail with reference to FIG. First, a structure on the positive electrode side composed of the upper and lower metal plates 10 and the positive electrode 20 will be described. Although not shown, the positive electrode 20 has a structure in which a positive electrode side active material, a mixture of a binder and a solvent are laminated. More specifically, in addition to lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and lithium cobaltate (LiCoO ₂ ) as active materials, a conductive agent such as acetylene black, a binder agent such as polyvinylidene fluoride, a solvent, After being mixed, it is formed by heating, pressurizing and molding in the steps described later. Although not shown, the positive electrode 20 is impregnated with an electrolyte solution having the composition described later.

  The upper and outer metal plate 10 is an external terminal on the positive electrode side of the flat battery 1, and stainless steel, aluminum or the like is used. In this embodiment, stainless steel having a thickness of approximately 200 μm is used. The upper and outer metal plate 10 also serves as a current collector of the positive electrode 20 by fixing the positive electrode 20.

  Next, the negative electrode side structure composed of the negative electrode 40 and the lower exterior metal plate 50 will be described. The negative electrode 40 has a structure in which a negative electrode side active material, a mixture of a binder and a solvent are laminated, although not shown. More specifically, it is formed by mixing graphite, a binder such as polyvinylidene fluoride, and a solvent, and then heating, pressurizing, and molding in a process described later. Although not shown in the drawing, the negative electrode 40 is impregnated with an electrolyte solution having the composition described later.

  The lower exterior metal plate 50 is an external terminal on the negative electrode side of the flat battery 1, and stainless steel, copper, nickel, etc. are used. In this embodiment, a copper plate having a thickness of about 200 μm and nickel-plated is used. It was. The lower exterior metal plate 50 also serves as a current collector of the negative electrode 40 by fixing the negative electrode 40 thereto.

  Next, the structure of the separator 30 will be described. The separator 30 is formed using a microporous polyethylene film having a thickness of approximately 20 μm. The separator 30 electrically isolates the positive electrode 20 and the negative electrode 40 and moves ions through the fine holes. In the present embodiment, the separator 30 is sandwiched between the positive electrode 20 and the negative electrode 40.

  Although not shown, the separator 30 is impregnated with an electrolytic solution having a composition described later.

Next, the electrolytic solution will be described. In this embodiment, the electrolyte uses lithium hexafluorophosphate (LiPF ₆ ), ethylene carbonate (EC), dimethyl carbonate (DE
C) was used as a solvent. In addition, the organic electrolyte solution melt | dissolved in the other individual or 2 or more types of mixed solvent can also be used.

  Next, the water-impervious frame 60, the adhesive layer 70u, and the adhesive layer 70d will be described. In this embodiment, the water-impervious frame 60 is made of a stainless material having a thickness of about 900 μm, and is formed in a cylindrical shape having a height B of about 0.9 mm.

  The adhesive layer 70u and the adhesive layer 70d are made of thermoplastic modified polypropylene and have a height W of approximately 200 μm and are formed in the same cylindrical shape as the water-impervious frame 60.

  Using the water-impervious frame 60, the adhesive layer 70u, and the adhesive layer 70d formed as described above, the adhesive layer 70u, the water-impervious frame 60, and the Three layers are heat-welded in the order of the adhesive layer 70d.

  It is also possible to use ceramic or glass as the water-impervious frame 60. In this case, electrical insulation between the upper exterior metal plate 10 and the lower exterior metal plate 50 is ensured, and there is an option of an adhesive for adhering the water shielding frame 60 to the upper exterior metal plate 10 and the lower exterior metal plate 50. spread.

  Next, the manufacturing process of the flat battery 1 will be described with reference to FIGS. The manufacturing process of the flat battery 1 is divided into an electrode coating process and an assembly process. First, the electrode coating process is performed in a dry room or in an air atmosphere, and then in a dry atmosphere known as a “blove box”. Perform the assembly process.

[Description of Electrode Coating Process of Manufacturing Process of Flat Battery 1: FIGS. 2 to 3]
First, the electrode coating process will be described with reference to FIGS. FIGS. 2A to 2D are cross-sectional views showing the electrode coating process for the negative electrode of the flat battery 1. As shown in FIGS. 2A and 2B, a coating mask SM is placed on the lower exterior metal plate base material 50p. Note that the lower exterior metal plate base material 50p is made of nickel having been plated on copper having a thickness of about 200 μm. The coating mask SM is made of a metal material such as aluminum and has an opening SMk having the same shape as the negative electrode 40.

  Next, as shown in FIG. 2C, the uncured negative electrode 40 </ b> S is filled into the cavity formed by the lower exterior metal plate base material 50 p and the opening SMk of the coating mask SM using the dispenser D. The uncured negative electrode 40S is a mixture of active material on the negative electrode side, a binder, and a solvent and is not cured. The filled uncured negative electrode 40S is cured after a certain period of time, and becomes an untreated negative electrode 40b as shown in FIG. The untreated negative electrode 40b is a state of the negative electrode before performing a process described later. After the untreated negative electrode 40b is formed, the coating mask SM is removed. Then, as shown in FIG. 2D, the lower exterior metal plate base material 50p and the untreated negative electrode 40b having a predetermined shape are fixed by the binder contained in the untreated negative electrode 40b. It is also possible to form the uncured negative electrode 40S by a method such as screen printing.

  Next, as shown in FIG. 3A, in the state where the lower exterior metal plate base material 50p and the untreated negative electrode 40b are fixed, they are heated at about 200 ° C. in the high-temperature vessel K and are included in the untreated negative electrode 40b. Solvent Y is evaporated.

  Next, as shown in FIG. 3B, the lower exterior metal plate base material 50p and the untreated negative electrode 40b are compressed using the press roller R, and the untreated negative electrode 40b is formed to a predetermined thickness. This is to uniformly compress the active material layer to eliminate non-uniform ion flow and improve various characteristics as a battery. It is also possible to use a pressure plate in place of the press roller R and compress the entire untreated negative electrode 40b at a time.

  Next, as shown in FIG. 3C, the lower exterior metal plate base material 50p is cut into a circular shape along the cutting line c, and the negative electrode 40 and the lower exterior metal plate 50 having a predetermined size are fixed to complete. And the electrode coating process about the structure by the side of the negative electrode of the flat battery 1 is completed.

  FIG. 3D is a cross-sectional view of the structure on the positive electrode side composed of the top and bottom metal plate 10 and the positive electrode 20, which is circular as in the case of the structure on the negative electrode side described above. Shows the completed state. As shown in FIG. 3 (d), the top and bottom metal plate 10 and the positive electrode 20 are fixed by a binder contained in the positive electrode 20.

[Description of Assembly Process of Manufacturing Process of Flat Battery 1: FIGS. 4 to 6]
Next, the assembly process of the flat battery 1 will be described with reference to FIGS. 4 to 6 are a cross-sectional view and an external view showing the assembly process of the flat battery 1.

  As illustrated in FIG. 4A, the negative electrode 40 of the negative electrode structure is impregnated with the electrolytic solution Es using the dispenser D. Similarly, as shown in FIG. 4B, the positive electrode 20 of the positive electrode structure is impregnated with the electrolytic solution Es. Similarly, as shown in FIG. 4C, the separator 30 is impregnated with the electrolytic solution Es.

  Next, as shown in FIG. 4D, the positive electrode 20 of the positive electrode structure and the negative electrode 40 of the negative electrode structure face each other with a separator 30 therebetween.

  Next, as shown in FIG. 4E, a DC voltage of approximately 4.2 V is applied between the upper and lower metal plates 10 and 50 using the charging power source J. Initial charging begins, and gas G is generated by decomposition of the electrolyte. When the generation of the gas G is finished, the application of the DC voltage by the charging power source J is finished.

  Next, the assembly process of the flat battery 1 will be described. As shown in FIG. 5A, the superposition of the positive electrode 20 of the positive electrode structure and the negative electrode 40 of the negative electrode structure is separated. At this time, the separator 30 remains overlaid on the negative electrode 40.

  Next, as shown in FIG. 5 (b), the ring-shaped water-impervious frame 60 is overlapped with the ring-shaped adhesive layer 70u and the adhesive layer 70d, respectively, and the overlapped surface is used with a cyanoacrylate adhesive. Temporarily fix.

  Next, as shown in FIG. 5 (c), the water blocking frame 60, the adhesive layer 70u, and the adhesive layer 70d are temporarily fixed and placed in a high-temperature tank K and left at approximately 170 ° C. for 2 hours.

  Then, as shown in FIG. 5D, a cylindrical water-impervious frame 60 having an adhesive layer 70u and an adhesive layer 70d on the upper and lower surfaces is completed.

  Next, the assembly process of the flat battery 1 will be described. As shown in FIG. 6A, the positive electrode 20 of the positive electrode structure and the negative electrode 40 of the negative electrode structure are again bonded together with a separator 30 interposed therebetween. At this time, the water-impervious frame 60 having the adhesive layer 70u and the adhesive layer 70d on the upper and lower surfaces is sandwiched between the upper and lower metal plates 10 and 50.

  Next, as shown in FIG. 6B, a pair of ring-shaped pressure plates P are used to press the portion of the water-impervious frame 60 provided with the adhesive layer 70u and the adhesive layer 70d as indicated by arrows. At the same time, heating is performed at about 170 ° C. for about 10 seconds, and the upper and lower metal plates 10 and the adhesive layer 70 u are thermally welded to the lower outer metal plate 50 and the adhesive layer 70 d, respectively.

  Through the above steps, the flat battery 1 shown in FIG. 6C is completed. FIG. 6D is a perspective view of the flat battery 1, and a flat battery 1 having a rectangular outer shape is shown as a variation of FIG. 1B.

[Description of a plurality of manufacturing steps of the flat battery 1: FIG. 7]
Next, a method of manufacturing a plurality of flat batteries 1 at a time will be described with reference to FIG. FIG. 7 is a cross-sectional view for explaining a method of manufacturing a plurality of flat batteries 1 at a time. As an example, a case of manufacturing three flat batteries 1 at a time will be described.
First, as shown in FIG. 7A, the collective coating mask SMb is attached to the lower exterior metal plate aggregate base material 50mp. The collective coating mask SMb is provided with a plurality of openings SMk according to the number of flat batteries 1 manufactured at a time, and in this embodiment, it is provided with three openings SMk. Note that the lower exterior metal plate aggregate base material 50mp is made of approximately 200 μm thick copper plated with nickel, and the aggregate coating mask SMb is made of a metal material such as aluminum.

  Next, as shown in FIG. 7B, the cavity surrounded by the lower exterior metal plate assembly base material 50mp and the three openings SMk is filled with the uncured negative electrode 40S using the dispenser D. After curing as the untreated negative electrode 40b shown in 7 (c), the collective coating mask SMb is removed.

  Then, as shown in FIG. 7C, three untreated negative electrodes 40b having a predetermined shape are formed on the lower exterior metal plate base material 50p.

  Next, as shown in FIG. 7 (d), the untreated negative electrode 40 b is formed on the lower exterior metal plate assembly base material 50 mp and heated in the high temperature bath K at about 200 ° C. The reason for heating is the same as in the case of the flat battery 1 and will not be described.

  Next, as shown in FIG. 7E, the untreated negative electrode 40b is compressed using three press rollers R so that the untreated negative electrode 40b has a predetermined thickness. The reason for compression is the same as in the case of the flat battery 1 and will not be described. Further, instead of the three press rollers R, three untreated negative electrodes 40b can be compressed together by using a pressure plate that can be compressed at once.

  Next, as shown in FIG. 7 (f), the lower exterior metal plate assembly base material 50mp is cut along the cutting line c, and the negative electrode 40 and the lower exterior metal plate 50 having a predetermined size are fixed to each other on the negative electrode side. Three structures are completed at a time.

  The electrode coating process in the manufacturing process for manufacturing the three flat batteries 1 at a time has been described by taking the negative electrode side as an example. However, the electrode coating process on the positive electrode side is the same as that on the negative electrode side, and thus the description thereof is omitted. Further, the subsequent assembling process is the same as the assembling process in the case of manufacturing the single flat battery 1 already described, and the description thereof will be omitted.

[Explanation of Effects of Flat Battery 1 of First Embodiment: FIG. 1]
The effect of the flat battery 1 will be described with reference to FIG. As shown in FIG. 1, in the flat battery 1 of this embodiment, the upper and lower metal plates 10 and the lower outer metal plate 50 are bonded via a water shielding frame 60, an adhesive layer 70u, and an adhesive layer 70d. ing.

In the structure of the flat battery 1, the path through which moisture flows from the outside is as follows. That is, since the materials for the upper and lower metal plates 10 and 50 and the water-impervious frame 60 are metals, the amount of moisture permeation can be ignored. Therefore, the moisture that flows into the flat battery 1 from the outside is only from the region in contact with the outside of the adhesive layer 70u and the adhesive layer 70d. Adhesive layer 70u and adhesive layer 70
The region in contact with the outside of d is a region formed by the total height 2W of the adhesive layer 70u and the adhesive layer 70d and the circumferential length of the adhesive layer 70u and the adhesive layer 70d. That is, in the cross-sectional view of the flat battery 1 shown in FIG. 1A, assuming that the cross-sectional area of the region where moisture flows from the outside is Vh, Vh = 2W × L = 2 × 0.2 × Lmm ² = 0. 4Lmm ^2
It is expressed as Here, W = 200 μm = 0.2 mm, and L is the circumferential length of the adhesive layer 70u and the adhesive layer 70d.

On the other hand, in the prior art described in Patent Document 1, only a polymer material is used in a portion corresponding to the water-impervious frame 60. Therefore, in the flat battery using the conventional technology having the same shape as that of the flat battery 1, there is a possibility that moisture flows from all the regions of the water shielding frame 60, the adhesive layer 70u, and the adhesive layer 70d shown in the present embodiment. Therefore, when the cross-sectional area of the region where moisture flows from the outside is Vj, Vj = (B + 2W) × L = 1.3 Lmm ² is expressed.

  In general, when moisture flows from one to the other, the amount of moisture inflow is proportional to “water vapor partial pressure difference”, “material characteristics of the inflow portion”, and “cross-sectional area of the inflow portion”, so the previous two items are Under the same conditions, the inflow amount of water is proportional to the “sectional area of the inflow portion”.

  That is, the cross-sectional area of the region where moisture flows from the outside in the flat battery 1 of the present invention is 1/3 times or less that of the flat battery according to the related art of the same shape. It can be said that the structure is an extremely effective technique for reducing the inflow of moisture from the outside and enhancing the reliability.

[Description of Flat Battery 2 of Second Embodiment: FIGS. 8 to 9]
Next, the flat battery 2 which is the 2nd Embodiment of this invention is demonstrated using FIGS. 8-9. FIG. 8 is a cross-sectional view showing the structure of the flat battery 2, and FIG. 9 is an enlarged cross-sectional view showing a partial structure of FIG.

  Compared with the flat battery 1 according to the first embodiment, the flat battery 2 according to the second embodiment has a method of joining the water-impervious frame 60 to the upper exterior metal plate 10 and the lower exterior metal plate 50. Different. That is, in the flat battery 1, the water-impervious frame 60 is thermally welded to the upper and lower metal plates 10 and 50 using the adhesive layer 70 u and the adhesive layer 70 d made of thermoplastic modified polypropylene. In the battery 2, the water-impervious frame 60 is bonded to the upper and lower exterior metal plates 10 and 50 using the adhesive layer 71 u and the adhesive layer 71 d.

   As shown in FIG. 8, the water-impervious frame 60 is joined to the upper exterior metal plate 10 and the lower exterior metal plate 50 by the adhesive layer 71 u and the adhesive layer 71 d. Since other elements are the same as those of the flat battery 1, the description thereof is omitted.

  The structure around the adhesive layer 71u and the adhesive layer 71d of the flat battery 2 will be described in detail with reference to FIG. FIG. 9 is an enlarged cross-sectional view illustrating an adhesive portion between the lower exterior metal plate 50, the adhesive layer 71d, and the water shielding frame 60. FIG. As shown in FIG. 9, the lower exterior metal plate 50 and the water-impervious frame 60 are bonded via an adhesive layer 71d.

  The adhesive layer 71d includes a spacer 72 and an adhesive 73. The spacer 72 electrically insulates the water-impervious frame 60 and the lower exterior metal plate 50, and bonds the water-impervious frame 60 and the lower exterior metal plate 50 together. It is a glass bead having a diameter of 0.1 mm to 10 μm for keeping the surface spacing Bs fine. The adhesive 73 is an electrically insulating adhesive that joins the lower exterior metal plate 50, the water-impervious frame 60, and the spacer 72. In this embodiment, a reactive acrylic adhesive is used. There are other available adhesives.

  In addition, since it is equivalent also about the adhesion part of the upper exterior metal plate 10, the adhesive layer 71u, and the water-impervious frame 60, description is abbreviate | omitted. Moreover, since the other structure and element of the flat battery 2 of 2nd Embodiment are equivalent to the flat battery 1 of 1st Embodiment, description is abbreviate | omitted.

[Description of Effects of Second Embodiment: FIGS. 8 to 9]
The effect of the flat battery 2 will be described with reference to FIGS. As shown in FIGS. 8 to 9, in the flat battery 2 of the present embodiment, the adhesive layer 71 u and the adhesive layer 71 d are both composed of a spacer 72 and an adhesive 73. The electrical and structural reliability of the joint surface between the upper exterior metal plate 10 and the lower exterior metal plate 50 is high.

  Further, the first effect of the flat battery 2 is that the adhesive layer 71u and the adhesive layer 71d are provided with the spacers 72, so that the interval Bs between the upper and lower metal plates 10 and the water-impervious frame 60 and the lower outer metal plate 50 The interval Bs between the water-impervious frame 60 can be kept small and precise to about 10 μm. If the interval Bs is small, the amount of inflow of moisture is further reduced, and the life and reliability of the flat battery are improved. Furthermore, the electrical insulation of the upper exterior metal plate 10 and the water-impervious frame 60 and the lower exterior metal plate 50 and the water-impervious frame 60 is ensured.

  The second effect of the flat battery 2 is that the seal width Bn of the bonding surface between the upper and outer metal plates 10 and the water shielding frame 60 and the lower outer metal plate 50 and the water shielding frame 60 can be reduced to about 500 to 1000 μm. It is. Since the adhesive layer 71u and the adhesive layer 71d are provided with fine spacers 72 of about 10 μm, the distance Bs between the upper and outer metal plates 10 and the water shielding frame 60 and the distance Bs between the lower outer metal plate 50 and the water shielding frame 60 are as follows. Since it can be narrowed to about 10 μm, the amount of the adhesive 73 at the interval Bs is reduced. In general, the smaller the amount of the adhesive, the higher the adhesive strength. Therefore, the adhesive strength of the adhesive surface between the upper exterior metal plate 10 and the water-impervious frame 60 and the lower exterior metal plate 50 and the water-impervious frame 60 is further increased.

  As a result, the seal width Bn of the joint surface between the upper exterior metal plate 10 and the water-impervious frame 60 and the lower exterior metal plate 50 and the water-impervious frame 60 is 500 to 1000 μm, which is significantly narrower than the seal width 5000 μm in a normal battery. Since the size of the positive electrode 20 and the negative electrode 40 can be increased by reducing the seal width Bn, the capacity of the flat battery 2 increases.

[Structural Explanation of Third Embodiment FIGS. 10 to 11]
Next, the flat battery 3 which is the 3rd Embodiment of this invention is demonstrated using FIGS. 10 is a cross-sectional view showing the structure of the flat battery 4, and FIG. 11 is an enlarged cross-sectional view showing a partial structure of FIG.

The flat battery 3 according to the third embodiment is different from the flat battery 2 according to the second embodiment in that each of the upper and lower metal plates 1, 51, and the water shielding frame 61 is provided. The difference is that a roughened region is provided on the surface in contact with the adhesive layer 74u and the adhesive layer 74d.
As shown in FIG. 10, the water-impervious frame 61 is bonded to the upper exterior metal plate 11 and the lower exterior metal plate 51 by an adhesive layer 74u and an adhesive layer 74d. Since other elements are the same as those of the flat battery 2, description thereof is omitted.

  The structure of the upper and outer metal plates 11, the water shielding frame 61, and the lower outer metal plate 51 of the flat battery 3 will be described in detail with reference to FIG. 11. FIG. 11 is an enlarged cross-sectional view illustrating a joint portion between the lower exterior metal plate 51, the adhesive layer 74 d, and the water-impervious frame 61. As shown in FIG. 11, a roughened region Rs and a flattened region Rh each having a roughened surface are formed in the lower exterior metal plate 51 and the water-impervious frame 61 one by one. In the roughened region Rs, the arithmetic average roughness is larger than that in the flattened region, and the adhesion area with the adhesive 73 is large.

  Since the same applies to the bonded portions of the upper exterior metal plate 11, the adhesive layer 74u, and the water-impervious frame 61, the details are omitted. Moreover, since the other structure and element of the flat battery of 3rd Embodiment are equivalent to the flat battery 2 of 2nd Embodiment, description is abbreviate | omitted.

[Description of Effects of Third Embodiment: FIGS. 10 to 11]
The effect of the flat battery 3 will be described with reference to FIGS. As shown in FIGS. 10 to 11, in the flat battery 3 of the present embodiment, the upper and outer metal plates 11, the water-impervious frame 6, and the lower outer metal plate 51 all have a roughened region Rs. So structural reliability is high.
The first effect of the flat battery 3 is that the arithmetic average roughness of the roughened region Rs is large, so that the adhesive force with the adhesive 73 can be increased. The higher the adhesive strength, the higher the resistance to positive electrode 20 and negative electrode 40 volume changes associated with charge / discharge, and the higher the reliability.

  Although the adhesion force is improved in the roughened region, as shown in FIG. 11, when the spacer 72 is arranged, the spacer 72 in the roughened region Rs is connected to the lower exterior metal plate 51 and the water-impervious frame 61. The height between the lower exterior metal plate 51 and the water-impervious frame 61 is not stable. Therefore, in the flat battery 3, since the flattened region Rh is provided in addition to the roughened region Rs, the lower exterior metal plate 51, the spacer 72, and the water-impervious frame are surely brought into contact with each other, and the height W1. Is stable at a value substantially equal to the diameter of the spacer 72. For this reason, when the spacer 72 is disposed, the flattened region Rh is provided so that the distance between the positive electrode 20 and the negative electrode 40 is formed uniformly, and the flat battery 3 with high reliability can be obtained. .

  As a result, it becomes possible to further reduce the seal width Bn of the joint surface between the upper exterior metal plate 11 and the water-impervious frame 61 and the lower exterior metal plate 51 and the water-impervious frame 61, and by reducing the seal width Bn Since the sizes of the positive electrode 20 and the negative electrode 40 can be increased, the capacity of the flat battery 3 is increased.

  In this embodiment, the roughened region Rs and the flattened region Rh are provided on the bonding surfaces of the upper and lower metal plates 11, 51 and the water shielding frame 61. A roughened region Rs is provided in one or both of at least a part of an adhesive surface to which the aqueous frame 61 is bonded and at least a part of an adhesive surface to which the lower exterior metal plate 51 and the water-impervious frame 61 are bonded. It doesn't matter.

[Structure Explanation of Fourth to Seventh Embodiments: FIGS. 12 to 13]
Next, with reference to FIGS. 12 to 13, the flat battery 4 according to the fourth embodiment of the present invention, the flat battery 5 according to the fifth embodiment, and the flat battery according to the sixth embodiment. 6 and the flat battery 7 according to the seventh embodiment will be described. FIG. 12 is a cross-sectional view showing the structure of the flat battery 4, and FIG. 13 is a cross-sectional view showing the structures of the flat battery 5, the flat battery 6, and the flat battery 7.

  The flat battery 4 to the flat battery 7 according to the fourth to seventh embodiments of the present invention are characterized by a water-impervious frame 60 and a lower exterior metal as compared to the flat battery 2 according to the second embodiment. The joining method with the board 50 is different.

  That is, in the flat battery 2, the water permeable frame 60 is bonded to the lower exterior metal plate 50 using the adhesive 73 contained in the adhesive layer 71 u and the adhesive layer 71 d, but in the flat battery 4 illustrated in FIG. The water shielding frame 61 is directly joined to the lower exterior metal plate 50. Note that “direct bonding” represents a state in which two materials are bonded at the molecular or atomic level of each material or at the molecular or atomic level of another material injected into each material by a technique such as sputtering.

The structure of the flat battery 4 which is the 4th Embodiment of this invention is explained in full detail using FIG. FIG. 12 is a cross-sectional view illustrating a structural example of the flat battery 4 according to the fourth embodiment. As shown in FIG. 12, the water-impervious frame 61 is made of stainless steel so that the bottom surface is L-shaped, and is directly joined to the lower exterior metal plate 50 at the welded portion DJ portion by a welding method. Since other structures and elements of the flat battery 4 are the same as those of the flat battery 2 according to the second embodiment, description thereof is omitted.

  Next, the structure of the flat battery 5 according to the fifth embodiment will be described with reference to FIG. FIG. 13A is a cross-sectional view illustrating the structure of the flat battery 5. As shown in FIG. 13A, the water-impervious frame 62 is formed using a ceramic material, and is directly coupled to the lower exterior metal plate 50 at the metal brazing portion KR by a metal brazing method. Since other structures and elements of the flat battery 5 are the same as those of the flat battery 2 according to the second embodiment, description thereof is omitted.

  Next, the structure of the flat battery 6 according to the sixth embodiment will be described with reference to FIG. FIG. 13B is a cross-sectional view showing the structure of the flat battery 6. As shown in FIG. 13B, the water-impervious frame 63 is formed using a glass material, and is directly bonded to the lower exterior metal plate 50 at the heat welding portion HR by the heat welding method. Since other structures and elements of the flat battery 6 are the same as those of the flat battery 2 according to the second embodiment, description thereof is omitted.

  Next, the structure of the flat battery 7 according to the seventh embodiment will be described with reference to FIG. FIG. 13C is a cross-sectional view showing the structure of the flat battery 7. As shown in FIG. 13 (c), the water-impervious frame is integrally formed with the lower exterior metal plate 50. Since other structures and elements of the flat battery 7 are the same as those of the flat battery 2 according to the second embodiment, description thereof is omitted. In FIG. 13C, the water-impervious frame is formed integrally with the lower exterior metal plate 50, but may be formed integrally with the upper exterior metal plate 10.

[Description of Effects of Flat Cells 4 to 7 of Fourth to Seventh Embodiments: FIGS. 12 to 13 (c)]
The effect of the flat battery 4 will be described with reference to FIG. As shown in FIG. 12, since the water-impervious frame 61 and the lower exterior metal plate 50 are directly joined between the metal structures by a welding method, the joining strength of the welded portion DJ, which is a joining point, is improved, and the flat battery 4 can increase the mechanical durability.

  Furthermore, compared with the flat battery 1 according to the first embodiment and the flat battery 2 according to the second embodiment, since the inflow path of moisture from the outside is reduced by one place, a highly reliable flat battery is obtained. realizable.

  The effects of the flat batteries 5 to 7 will be described with reference to FIGS. 13 (a) to 13 (c). As shown in FIGS. 13A and 13B, the water-impervious frames 62 and 63 and the lower exterior metal plate 50 are directly joined by a metal brazing method or a heat welding method. Further, as shown in FIG. 13C, since the water-impervious frame and the lower exterior metal plate 50 are integrally formed, the water inflow path from the outside is reduced by one place, and the upper exterior metal plate Since the electrical insulation between 10 and the lower exterior metal plate 50 is ensured, a highly reliable flat battery can be realized.

  In the fourth to seventh embodiments, the adhesive layer 71u containing the spacer 72 described in the second embodiment is used. However, the adhesive layer 70u not including the spacer 72 described in the first embodiment is used. You may use. Further, as described in the third embodiment, the roughened region Rs and the flattened region Rh may be provided on the bonding surface between the upper exterior metal plate 10 and the water-impervious frame 62, 63.

[Description of Structure of Eighth Embodiment]
Next, the flat battery 8 which is the 8th Embodiment of this invention is demonstrated using FIGS. 14-15. 14 is a cross-sectional view showing the structure of the flat battery 8, and FIG. 15 is a cross-sectional view and a plan view showing the assembly method.

  The flat battery 8 according to the eighth example is different from the flat battery 1 according to the first embodiment in that it is formed by adding a heat insulating ring 80. That is, in the flat battery 1, there is a gap between the water-impervious frame 60, the positive electrode 20, the negative electrode 40, and the separator 30, but in the flat battery 8, a heat insulating ring 80 is formed.

  As shown in FIG. 14, the heat insulating ring 80 is formed between the adhesive layer 70 u, the adhesive layer 70 d, and the water shielding frame 60, the positive electrode 20, the separator 30, and the negative electrode 40. The heat insulating ring 80 may be made of a material having a low thermal conductivity such as polypropylene and having an insulating property. Since other elements are the same as those of the flat battery 1, description thereof is omitted.

[Description of assembly process of flat battery 8: FIG. 15]
A method for manufacturing the flat battery 8 will be described with reference to FIG. FIG. 15A is a top view showing the assembly process of the flat battery 8, and FIG. 15B is a cross-sectional view taken along the line BB ′ of FIG. In the flat battery 1, the upper and outer metal plates 10, the adhesive layer 70 u, the water-impervious frame 60, the adhesive layer 70 d, and the lower outer metal plate 50 are superposed in this order, and then heat is applied from above and below using the heating plate P. However, in the flat battery 8, as shown in FIGS. 15A and 15B, the welding head 110 moves in the direction of the arrow and is brought into contact with the outer peripheral portion of the water-impervious frame 60. The welding head 110 is heated, and the adhesive layer 70 u and the adhesive layer 70 d are dissolved via the water-impervious frame 60 to adhere the upper and outer metal plates 10 and 50 to the water-impervious frame 60. Since other manufacturing methods are the same as those of the flat battery 1, description thereof is omitted.

[Explanation of Effects of Seventh Embodiment FIGS. 14 to 15]
The effect of the flat battery 8 will be described with reference to FIGS. As shown in FIGS. 14 to 15, since the heat insulating ring 80 is formed, the heat from the welding head 110 is not easily transmitted to the positive electrode 20, the separator 30, and the negative electrode 40. In the flat battery 1, heat is applied from above and below, so that the heat is transmitted to the positive electrode 20 and the negative electrode 40 via the upper and lower outer metal plates 10 and 50 having high thermal conductivity and is impregnated. There was a risk of volatilizing. However, in the flat battery 8, even if the water-impervious frame 60 is sufficiently heated, the heat insulating ring 80 is provided, so that the heat transfer to the positive electrode 20, the separator 30, and the negative electrode 40 is greatly suppressed, and the initial characteristics are high. A flat battery can be realized.

  In the eighth embodiment, the adhesive layers 70u and 70d that do not contain the spacer described in the first embodiment are used. However, the adhesive layers 71u and 71d including the spacer 72 described in the second embodiment are used. It doesn't matter. Further, as described in the third embodiment, the roughened region Rs and the flattened region Rh may be provided on the bonding surface between the upper exterior metal plate 10 and the water-impervious frame 62, 63.

  According to the present invention, since the flat battery can be made thinner, it is optimal as an application to a secondary battery of a card type or sheet type electronic device.

1, 2, 3, 4, 5 Flat battery 10 Upper and lower metal plate 20 Positive electrode 30 Separator 40 Negative electrode 40b Untreated negative electrode 40S Uncured negative electrode 50 Lower outer metal plate 50p Lower outer metal plate base material
50mp lower exterior metal plate assembly base material 60, 61, 62, 63 Water-proof frame 70u, 70d, 71u, 71d, 74u, 74d Adhesive layer (resin sealing material)
72 Spacer 73 Adhesive 110 Welding head B Height of water-impervious frame Bs Interval Bn Seal width c Cut section DJ Direct coupling portion D Dispenser Es Electrolyte G Gas J Charging power source K High-temperature tank L Circumferential length KR Metal brazing Attached part HR Heat welding part P Pressing plate R Press roller SM Coating mask SMb Aggregate coating mask SMk Opening Vh, Vj Cross-sectional area Y of water inflow area Y Solvent W Adhesive layer height 100 Thin battery 101 Positive electrode terminal Plate 101 ′ Negative electrode terminal plate 102 Insulating thermal adhesive resin 104 Negative electrode portion

Claims (7)

  A flat battery in which an electrode is sandwiched between an upper exterior metal plate and a lower exterior metal plate, and the upper exterior metal plate and the lower exterior metal plate are bonded via a water-impervious frame. A flat battery characterized by.   The flat battery according to claim 1, wherein the water-impervious frame is made of metal, ceramic, or glass.   3. The flat battery according to claim 1, wherein a spacer is disposed between the upper exterior metal plate or the lower exterior metal plate and the water-impervious frame. 4. At least one part of an adhesive surface for joining the upper exterior metal plate and the water-impervious frame, and at least one part of an adhesive surface for joining the lower exterior metal plate and the water-impervious frame, either or both, The flat battery according to any one of claims 1 to 3, wherein a roughened region is provided. The flat battery according to any one of claims 1 to 4, wherein a heat insulating ring is disposed between the water-impervious frame and the electrode.   The flatness according to any one of claims 1 to 5, wherein any one of the upper exterior metal plate and the lower exterior metal plate and the water-impervious frame are directly coupled to each other. Type battery.   6. The device according to claim 1, wherein either the upper exterior metal plate or the lower exterior metal plate and the water-impervious frame are integrally formed. Flat battery.

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