JP6264188B2 - Power storage device, electronic device using the same, and power storage unit - Google Patents

Description

  The present invention relates to a power storage device, an electronic device using the power storage device, and a power storage unit.

  In recent years, lithium ion secondary batteries have been widely used as power sources and power storage devices for consumer electronic devices such as information terminals and game machines such as mobile phones and smartphones. In such an electronic device, in addition to a long life and high capacity, there is an increasing demand for a battery having flexibility in order to obtain a light weight, a small size, and a degree of freedom in external design. By realizing a flexible power storage device, the power storage device can be installed in a curved or bent portion or a thin portion such as a wearable device such as a wristwatch or a thin electronic device.

A conventional non-aqueous lithium ion secondary battery includes a positive electrode in which a positive electrode active material that releases lithium ions is applied to a sheet-like current collector such as aluminum or copper, and a negative electrode in which a negative electrode active material that absorbs lithium ions is applied. Have. It is obtained by sandwiching a separator between the positive electrode and the negative electrode, winding the separator to form a wound body, and encapsulating the wound body together with the electrolyte in the exterior body. Although the positive electrode, the separator, and the negative electrode are each flexible members, the shape is fixed after the wound body is formed and sealed in the exterior body, so the flexibility is completely lost, and the battery Could not be given a degree of freedom of bending or bending.
Moreover, an organic solvent is used as an electrolyte in such a non-aqueous lithium ion secondary battery. For this reason, there is a risk of liquid leakage by bending or bending the battery.

  Therefore, research on a thin solid battery using an inorganic solid electrolyte instead of an organic solvent as an electrolyte as disclosed in Patent Document 1 and a sheet-shaped power storage device as disclosed in Patent Document 2 is actively conducted. Has been done.

Japanese Patent Laid-Open No. 2007-123081 JP 2013-239435 A

  However, in a thin solid battery as disclosed in Patent Document 1, there is a possibility that a short circuit or a crack between the positive electrode and the negative electrode may occur when the battery is bent or bent. There wasn't. Although the sheet-type power storage device disclosed in Patent Document 2 can cope with bending and bending, it cannot cope with the twist required for the wearable device. Furthermore, if the mounting density of the power storage elements constituting the power storage device is increased in order to increase the capacity of the power storage device, it becomes more difficult to cope with the twist.

  SUMMARY An advantage of some aspects of the invention is to provide a power storage device having a large capacity corresponding to bending, bending, and twisting, an electronic device using the power storage device, and a power storage unit.

  In order to solve the above problems, a power storage device according to the present invention is a first in which a conductive wire extending in a predetermined direction and a plurality of solid state batteries are arranged in a predetermined direction and connected in parallel on at least one main surface of a flexible substrate. A battery group and a second battery group in which a plurality of solid state batteries are arranged in parallel and connected in parallel, and the solid state of the first battery group when projected from either the predetermined direction or the orthogonal direction perpendicular thereto The battery and the solid battery of the second battery group are arranged at different positions, and the first battery group and the second battery group are connected in series by arranging terminals having different polarities on the same conductor. It is characterized by being.

  According to this power storage device, since the solid state batteries are alternately arranged on the flexible substrate, it is possible to cope with bending, bending, and twisting.

  The power storage device according to the present invention is disposed at a position where a part of the solid state battery of the first battery group and a part of the solid state battery of the second battery group overlap each other when the power storage device is projected from a predetermined direction. It is preferable.

  According to such a power storage device, it is possible to cope with bending, bending, and twisting, and to improve the capacity by high-density mounting.

  In the power storage device according to the present invention, it is further preferable that the first battery group and the second battery group are alternately arranged on the same main surface.

  According to such a power storage device, since the solid batteries are alternately arranged on the flexible substrate, it is easy to cope with the twist, the load on the solid battery caused by the twist is reduced, and the high density mounting is performed. It is possible to improve the capacity.

  The electronic device according to the present invention preferably includes a power storage device.

  According to such an electronic device, since the power storage device can be mounted on a portion where bending, bending, or twisting occurs, an electronic device with a higher degree of freedom can be provided.

  In the power storage unit according to the present invention, it is preferable that a sheet-like solar power generation element is bonded to the opposite side of the main surface, and the power storage device and the solar power generation element are electrically connected.

  According to this power storage unit, a flexible solar power storage unit can be obtained. Moreover, the solid battery is warmed by the heat of the sun, and the performance improvement of the solid battery can be expected.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage apparatus with a large capacity | capacitance corresponding to a curve or bending, and a twist, an electronic device using the same, and an electrical storage unit can be provided.

It is a schematic diagram of a power storage device. It is a schematic diagram of the example of the electrical storage apparatus which repeated the 1st battery group and the 2nd battery group in the orthogonal direction. It is a schematic diagram of the example of the electrical storage apparatus which repeated the 1st battery group and the 2nd battery group in the orthogonal direction. It is a schematic diagram of the example of the electrical storage apparatus which arranged the battery group containing the 2nd battery group which has the same period as a 1st battery group in the orthogonal direction. It is a schematic diagram of the example of the electrical storage apparatus which arranged the battery group from which the periodicity of a predetermined direction differs in the orthogonal direction. It is a schematic diagram of a solid battery. It is a schematic diagram of the electrical storage unit combined with the solar power generation element.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment. Furthermore, the constituent elements described below can be appropriately combined.

(Power storage device)
FIG. 1 is a plan view showing a power storage device 50 according to this embodiment. As shown in FIG. 1, the power storage device 50 mainly includes a flexible substrate 1 and a first battery group 2 and a second battery group 3 disposed on one main surface of the flexible substrate 1. The first battery group 2 and the second battery group 3 are each composed of a plurality of solid batteries 10. The conducting wire 4 extends in a predetermined direction, and a plurality of conducting wires 4 are provided on the surface or inside of the flexible substrate 1 to carry a part of the circuit. The solid battery 10 is electrically connected to the conducting wire 4.

(Battery arrangement)
The first battery group 2 and the second battery group 3 are each composed of a plurality of solid state batteries 10 arranged in a predetermined direction. When the second battery group 3 is projected from either a predetermined direction or an orthogonal direction orthogonal to the predetermined direction, the solid state batteries 10 of the first battery group 2 and the second battery group 3 are arranged at different positions. Therefore, the solid battery 10 can be mounted on the flexible substrate 1 with high density, which is preferable.

  If the overlap between the first battery group 2 and the second battery group 3 when projected from a predetermined direction is large, even if the mounting density of the solid battery is increased in order to increase the capacity of the power storage device, the flexibility This is preferable because the load applied to the solid state battery when the substrate 1 is bent, bent, or twisted is dispersed and reduced.

(Sequence after the third column)
2 to 5 are examples of a power storage device having a battery arrangement different from that in FIG. As shown in FIGS. 1 to 5, when the first battery group 2 is arranged in the first row and the second battery group 3 is arranged as the second row in the orthogonal direction, a plurality of solid state batteries are arranged in a predetermined direction in the third row and thereafter. It is preferable to arrange the battery groups arranged and connected to each other and connect them in series with the battery groups including the second battery group arranged in the orthogonal direction. FIGS. 2 to 5 schematically show examples of the arrangement of solid batteries in the case of a 4-series-3 parallel arrangement. After the third row, the first battery group 2 and the second battery group 3 may be arranged alternately as shown in FIGS. 2 and 3, or the first battery group 2 and the second battery group 3 as shown in FIGS. A battery group different from the second battery group 3 may be arranged. When battery groups different from the first battery group 2 and the second battery group 3 are arranged in the orthogonal direction, one solid battery 10 constituting the first battery group 2 and one solid battery constituting the second battery group 3 It is only necessary that the solid batteries 10 of the battery groups in the third and subsequent rows are arranged on a straight line connecting the 10 centers of gravity.

  The higher the symmetry of the arrangement of the solid state batteries 10 arranged on the flexible substrate, the easier it is to deal with high density mounting and twisting. Therefore, the first battery group 2 and the second battery group 3 are arranged alternately. Is preferred. Moreover, although the space | interval between the battery groups arranged in the orthogonal direction is not specifically defined, it is preferable that it is equal intervals.

(wiring)
In the power storage device shown in FIG. 1, four wires are formed in parallel to the longitudinal direction on the rectangular flexible substrate 1. Among them, a solid battery is mounted so as to straddle two adjacent conductive wires 4. In FIG. 1, six solid batteries 10 constituting one first battery group 2 are connected in parallel, and six solid batteries 10 constituting one second battery group 3 are also connected in parallel. The first battery group 2 and the second battery group 3 are connected in series. Thus, in FIG. 1, a 4 series-6 parallel power storage device is configured. This power storage device has excellent compatibility with high-density mounting and bending or bending and twisting in that the terminal electrodes having different polarities of the first battery group 2 and the second battery group 3 are arranged on the same conductor. It will be a thing. In addition, the solid battery 10 expands and contracts because ions move during charging and discharging, but in order to prevent the solid battery 10 from falling off the flexible substrate 1, it is preferable that the area where the solid battery and the conductor are in contact with each other is large. The width of the conducting wire is preferably 1/3 or more of the distance between the terminal electrodes 18 of the solid battery 10.

  The wiring according to the present embodiment is not limited to that shown in FIG. 1, and can be widely changed according to the capacity and current specifications required for the power storage device 50. Further, electronic components other than the solid battery 10 may be mounted on the substrate, and for example, a rectifier circuit, a protection circuit, an IC chip, etc. may be provided, and the first battery group 2 and the second battery group 3 may be provided. You may provide the solid battery etc. which are not contained in the battery group including the first.

  When a plurality of solid batteries 10 are connected in parallel to form a battery group including the first battery group 2 and the second battery group 3, and the plurality of battery groups are connected in series, the solid batteries 10 connected in parallel are When the capacities different from each other or the groups of batteries connected in series have different capacities, there is a possibility that the power storage device 50 constituted by them has a reduced charge / discharge efficiency or an overcharged state. Therefore, it is preferable that the capacity | capacitance of the solid battery 10 connected in parallel which comprises one battery group is the same mutually, and the battery group connected in series is mutually the same capacity | capacitance.

  It is preferable that the number of solid batteries 10 connected in parallel constituting one battery group or the number of battery groups connected in series is large. A plurality of solid state batteries 10 are connected in parallel to form a battery group, and the plurality of battery groups are connected in series while sharing a lead wire with an adjacent battery group, so Even if a change in electrical resistance or capacity occurs due to a short circuit or a cracked connection failure or an internal short circuit in the solid battery 10, the amount of change in load applied to one of the solid batteries 10 constituting the power storage device is small. Therefore, it is preferable because the current value and voltage value of the power storage device can be maintained.

  In the power storage device shown in FIG. 1, the first battery group 2 and the second battery group 3 are alternately arranged, and the solid state batteries 10 are periodically arranged at regular intervals in any of the predetermined direction and the orthogonal direction. Has been. Furthermore, the arrangement of the first battery group 2 and the second battery group 3 is parallel, and the arrangement of the solid batteries 10 constituting the second battery group 3 is in the predetermined direction of the solid batteries 10 constituting the first battery group 2. The first battery group 2 is arranged in the predetermined direction with the same period as that of the first battery group 2 by shifting by half of the period. Since the arrangement of the solid batteries 10 on the flexible substrate 1 has high symmetry, even when the same number of solid batteries 10 are mounted at high density, it is easy to cope with bending, bending, or twisting. Therefore, it is preferable.

  The material that can be used for the conductive wire 4 is not particularly limited as long as it is a conductive material. However, since the flexible substrate 1 needs to be tracked and bent, it has excellent malleability and ductility. Preferably, the material is For example, it is preferable to use metals such as gold, platinum, copper, aluminum, titanium, stainless steel, iron, and zinc, and alloys thereof.

(Flexible substrate material)
The flexible substrate 1 is preferably a substrate made of a resin material such as a flexible printed substrate. More specifically, plastic materials such as polyether sulfone, polycarbonate, polyarylate, polyethylene terephthalate, polyethylene naphthalate, polyimide, polypropylene, and polyester can be used. By using a resin material, it is possible to provide flexibility while maintaining high strength with a thin film and light weight compared to the case of using glass or metal material. As a result, it is possible to reduce the thickness and weight of the power storage device, which is suitable for application to wearable devices.

(Connection with the base)
For connecting the terminal electrode 16 of the solid battery 10 and the conductive wire 4, a technique of mounting an electronic component on a circuit board can be used. As the material, solder, cream solder, lead-free solder, lead-free solder paste, carbon paste, conductive paste, metal-containing resin, or the like can be used. When using cream solder or lead-free solder paste, cure it through a reflow oven. The peak temperature of the reflow furnace is preferably about 200 to 280 ° C.

  Next, a method for manufacturing the power storage device of this embodiment will be described in order.

(Structure of solid battery)
FIG. 6 is a schematic cross-sectional view of the solid state battery 10 mounted on the power storage device in the present embodiment. The solid battery 10 includes a solid electrolyte layer 13 between a positive electrode layer 11 and a negative electrode layer 12. The positive electrode layer 11 includes a positive electrode current collector layer 14 and a positive electrode active material layer 15. The negative electrode layer 12 is a negative electrode. It consists of a current collector layer 16 and a negative electrode active material layer 17. Further, since the positive electrode current collector 14 and the negative electrode current collector 16 are in electrical contact with the outside, the terminal electrode 18 is electrically connected. More preferably, a protective layer made of resin, ceramics, glass, or the like is provided on the surface of the solid battery 10 so that moisture in the atmosphere does not react with the solid battery 10. FIG. 6 shows a cross-sectional view of a parallel type solid battery 10 in which five battery cells are stacked. However, the technology related to the solid battery 10 of the present embodiment is not limited to the parallel type in which the five battery cells shown in FIG. Applicable. The present invention is not limited to that shown in FIG. 6, and can be widely changed according to the capacity and current specifications required for the power storage device 50.

(Solid electrolyte)
As the solid electrolyte constituting the solid electrolyte layer 13 of the present embodiment, it is preferable to use a material having low electron conductivity and high lithium ion conductivity. Moreover, it is preferable that it is an inorganic material which can be baked at high temperature in an atmospheric condition. For example, perovskite type compounds such as La _0.5 Li _0.5 TiO ₃ , silicon type compounds such as Li ₁₄ Zn (GeO ₄ ) ₄ , garnet type compounds such as Li ₇ La ₃ Zr ₂ O ₁₂ , Li _1. NASICON compounds such as ₃ Al _0.3 Ti _1.7 (PO ₄ ) ₃ and Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ , Li _3.25 Ge _0.25 P _0.75 Thiolicone type compounds such as S ₄ and Li ₃ PS ₄ , glass compounds such as Li ₂ S—P ₂ S ₅ and Li ₂ O—V ₂ O ₅ —SiO ₂ , Li ₃ PO ₄ and Li _3.5 Si _0. It is desirable that it is at least one selected from the group consisting of phosphoric acid compounds such as ₅ P _0.5 O ₄ and Li _2.9 PO _3.3 N _0.46 .

(Current collector material)
Specific examples of the conductive material constituting the positive electrode current collector layer 15 and the negative electrode current collector layer 17 include gold (Au), platinum (Pt), platinum (Pt) -palladium (Pd), silver (Ag), Silver (Ag) -palladium (Pd), aluminum (Al), copper (Cu), indium-tin oxide film (ITO), and the like can be given.

(Positive electrode active material and negative electrode active material)
As the positive electrode active material and the negative electrode active material constituting the positive electrode active material layer 14 and the negative electrode active material layer 16 constituting the solid battery 10 of the present embodiment, it is preferable to use a material that efficiently releases and occludes lithium ions. For example, it is preferable to use a transition metal oxide or a transition metal composite oxide. Specifically, the lithium manganese composite oxide _{Li 2 Mn x3 Ma 1-x3} O 3 (0.8 ≦ x3 ≦ 1, Ma = Co, Ni), lithium cobaltate (LiCoO _2), lithium nickelate (LiNiO ₂ ), Lithium manganese spinel (LiMn ₂ O ₄ ), and a general formula: LiNi _x4 Co _y4 Mn _z4 O ₂ (x4 + y4 + z4 = 1, 0 ≦ x4 ≦ 1, 0 ≦ y4 ≦ 1, 0 ≦ z4 ≦ 1) Composite metal oxide, lithium vanadium compound (LiV ₂ O ₅ ), olivine type LiMbPO ₄ (where Mb is one or more selected from Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, Zr) Element), lithium vanadium phosphate (Li ₃ V ₂ (PO ₄ ) ₃ or LiVOPO ₄ ), Li-rich solid solution positive electrode Li ₂ MnO ₃ -L iMcO ₂ (Mc = Mn, Co, Ni), lithium titanate (Li ₄ Ti ₅ O ₁₂ ), LiaNi _x5 Co _y5 Al _z5 O ₂ (0.9 <a <1.3, 0.9 <x5 + y5 + z5 <1 .1) is preferably one of the composite metal oxides represented by

  Here, there is no clear distinction between the active materials constituting the positive electrode active material layer 14 or the negative electrode active material layer 16, and a compound showing a lower potential by using a compound having a noble potential as the positive electrode active material layer 16. Can be used as the negative electrode active material layer 16. Moreover, the active material which comprises the positive electrode active material layer 14 and the active material which comprises the negative electrode active material layer 16 may use the same material, and may differ.

(Manufacture of solid batteries)
The solid battery 10 electrolyte layer 13, the positive electrode active material layer 14, the negative electrode active material layer 16, the positive electrode current collector layer 15, and the negative electrode current collector layer 17 of the present embodiment are pasted, and then applied and dried. A green sheet is produced, and the green sheet is laminated and pressed to form a laminated body, and the laminated body is manufactured by simultaneous firing.

(Preparation of paste)
The method for forming the paste is not particularly limited, and for example, a paste can be obtained by mixing the powder of each of the above materials in a vehicle. Here, the vehicle is a general term for the medium in the liquid phase. The vehicle includes a solvent and a binder. By this method, the paste for the positive electrode current collector layer 14, the paste for the positive electrode active material layer 15, the paste for the solid electrolyte layer 13, the paste for the negative electrode active material layer 16, and the negative electrode current collector layer 17 Make a paste.

  The composition of the paste is not particularly limited. For example, the paste for the positive electrode active material layer 14 and the paste for the negative electrode active material layer 16 may contain a solid electrolyte, a sintering aid, and a conductive material in addition to the active material, or the positive electrode current collector The paste for the layer 15 and the negative electrode current collector 17 may contain an active material, a solid electrolyte, and a sintering aid.

  The prepared paste is applied in a desired order on a base material such as PET (polyethylene terephthalate) and dried as necessary, and then the base material is peeled to prepare a green sheet. The paste application method is not particularly limited, and a known method such as screen printing, application, transfer, doctor blade, or the like can be employed.

  The green sheets for the produced positive electrode current collector layer 14, positive electrode active material layer 15, solid electrolyte layer 13, negative electrode active material layer 17, and negative electrode current collector layer 16 are laminated in a desired order and stacked. Stacked by number, alignment, cutting, etc. are performed as necessary to produce a laminate. In the case of manufacturing a parallel type or series-parallel type battery, it is preferable to align and stack the end surfaces of the positive electrode layer and the negative electrode layer so that they do not coincide with each other.

  The produced laminate is pressed together. The pressure bonding is performed while heating, and the heating temperature is, for example, 40 to 90 ° C.

  The obtained laminate is cut as necessary and cut to a desired dimension. Although the cutting method is not limited, for example, it may be performed with a dicing saw or a knife cutting machine. The cutting is preferably performed after alignment.

  For example, the laminated body is heated and fired in an air atmosphere to obtain a sintered body. The firing temperature is preferably in the range of 600 to 1200 ° C. If the temperature is lower than 600 ° C., the firing does not proceed sufficiently, and if the temperature exceeds 1200 ° C., problems such as melting of the solid electrolyte and changes in the structure of the positive electrode active material and the negative electrode active material may occur. Furthermore, it is more preferable that the temperature is in the range of 700 to 1100 ° C. because the firing is accelerated and the manufacturing cost is reduced. The firing time is preferably, for example, 0.1 to 3 hours.

  You may perform dry barrel grinding | polishing or wet barrel grinding | polishing with respect to the sintered compact of a laminated body. At this time, it is preferable to use an abrasive such as alumina, zirconia, or resin beads. In the case of a wet barrel, the solvent is not particularly limited, but those mainly composed of ion-exchanged water, pure water, and a fluorinated solvent are preferable.

  A method for forming the terminal electrode 18 is not limited, but a technique used for an electronic component or the like can be used. For example, it is preferably formed by dipping, sputtering, vacuum deposition, or plating of a thermosetting conductive paste. The terminal electrode 18 is formed by such a forming method, and the solid battery 10 is obtained.

  The material of the terminal electrode 18 is preferably a conductive material, for example, gold (Au), platinum (Pt), platinum (Pt) -palladium (Pd), silver (Ag), silver (Ag) -palladium ( A material mainly containing Pd), aluminum (Al), copper (Cu), indium, and indium-tin oxide film (ITO) can be used.

  In order to improve reliability, a coating film made of resin, glass, or ceramic may be formed on the surface of the sintered body, or may be housed in a highly airtight case.

(Method for manufacturing power storage device)
Using the solid battery 10 described above, as shown in FIG. 1, a flexible substrate 1 provided with wiring 4 in advance is prepared, and the solid battery 10 is mounted on the wiring by the mounting method described above. In this way, a power storage device is obtained.

(Solid battery orientation when mounted)
The solid battery 10 may expand and contract due to occlusion of lithium ions. When the solid battery 10 is mounted on the flexible substrate, since the expansion and contraction in the stacking direction of the laminate constituting the solid battery 10 is large, the distance between the adjacent solid batteries 10 can be shortened. It is preferable to mount in a direction in which the stacking direction of the stacked body constituting the battery 10 is orthogonal to the flexible substrate. Regarding the orientation of the solid battery in the plane, the line connecting the terminal electrodes 18 of the solid battery may be parallel to or inclined with respect to the conductive wire 4, but it is better that all the batteries are in the same direction. This is preferable because the mounting density can be easily increased.

  Further, the surface on which the solid battery is mounted may be one side of the flexible substrate, or may be both sides. At this time, when the solid battery is projected from one main surface side of the flexible substrate toward the back surface, the arrangement of the solid battery mounted on the back surface is the same as the main surface or in the predetermined direction by the arrangement of the main surface. The arrangement is preferably shifted in parallel.

(Margins around the solid battery)
In order to prevent the distance between adjacent solid batteries from becoming narrow due to expansion of the solid battery, it is preferable to maintain a space around the solid battery when the solid battery is mounted.

(Electronics)
The power storage device according to the present invention is preferably used for a flexible electronic device or a bent portion of the electronic device. For example, it is preferable to combine with a wristwatch or a thin electronic device.

(Electric storage unit)
FIG. 7 shows a conceptual schematic diagram of a power storage unit in which the power storage device according to the present invention is combined with the photovoltaic power generation element 20. As the power generation element combined with the power storage device described above, a piezoelectric element, a thermoelectric conversion element, or the like can be used in addition to the solar power generation element, but a flexible power generation element is preferable. Among these, a sheet-like photovoltaic power generation element is suitable. The solid battery can operate even at a high temperature, and the higher the temperature, the better the battery characteristics of the solid battery can be expected. A power storage unit that can be driven more stably is obtained by heating the power storage unit with sunlight.

Example 1
EXAMPLES The present invention will be described in detail below using examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated, a part display is a weight part.

(Production of active material)
Li ₃ V ₂ (PO ₄ ) ₃ produced by the following method was used as the active material. Using Li ₂ CO ₃ , V ₂ O ₅ and NH ₄ H ₂ PO ₄ as starting materials, these were weighed so as to have a molar ratio of 3: 2: 6, and wet mixed in a ball mill for 16 hours using water as a solvent. And then dehydrated and dried. The obtained powder was calcined in a nitrogen-hydrogen mixed gas at 850 ° C. for 2 hours. The calcined product was coarsely pulverized, wet pulverized with a ball mill for 16 hours using water as a solvent, and then dehydrated and dried to obtain an active material powder. It was confirmed using an X-ray diffractometer that the composition of the produced powder was Li ₃ V ₂ (PO ₄ ) ₃ .

(Production of active material paste)
The active material paste was prepared by adding 15 parts of ethyl cellulose as a binder and 65 parts of dihydroterpineol as a solvent to 100 parts of this active material powder, and kneading and dispersing with three rolls.

(Preparation of solid electrolyte sheet)
As the solid electrolyte, Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ prepared by the following method was used. Using Li ₂ CO ₃ , Al ₂ O ₃ , TiO ₂ and NH ₄ H ₂ PO ₄ as starting materials, these were weighed to a molar ratio of 0.65: 0.15: 1.7: 3, and water was added. After wet mixing with a ball mill as a solvent for 16 hours, it was dehydrated and dried. The obtained powder was calcined in air at 800 ° C. for 2 hours. The calcined product was coarsely pulverized, wet pulverized with a ball mill for 24 hours using water as a solvent, and then dehydrated and dried to obtain a solid electrolyte powder. It was confirmed using an X-ray diffractometer that the composition of the produced powder was Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ .

  Next, 100 parts of ethanol and 200 parts of toluene were added to 100 parts of the powder by a ball mill and wet mixed. Thereafter, 16 parts of polyvinyl butyral binder and 4.8 parts of benzylbutyl phthalate were further added and mixed to prepare a solid electrolyte paste. This solid electrolyte paste was formed into a sheet by a doctor blade method using a PET film as a base material to obtain a solid electrolyte sheet having a thickness of 15 μm.

(Preparation of current collector paste)
After mixing Cu and Li ₃ V ₂ (PO ₄ ) ₃ as a current collector so as to have a volume ratio of 6: 4, 10 parts of ethyl cellulose as a binder and 50 parts of dihydroterpineol as a solvent are added to form a three-roll. A current collector paste was prepared by kneading and dispersing.

(Preparation of terminal electrode paste)
Silver powder, epoxy resin, and solvent were kneaded and dispersed with three rolls to produce a thermosetting conductive paste.

(Production of green sheets for active material units)
An active material paste was printed on the solid electrolyte sheet with a thickness of 5 μm by screen printing. Next, the printed active material paste was dried at 80 ° C. for 5 minutes, and a current collector paste was printed thereon with a thickness of 5 μm by screen printing. Next, the printed current collector paste was dried at 80 ° C. for 5 minutes, and further, the active material paste was printed again at a thickness of 5 μm by screen printing. The printed active material paste was dried at 80 ° C. for 5 minutes, and then the PET film was peeled off. In this way, an active material unit green sheet was obtained in which the active material paste, the current collector paste, and the active material paste were printed and dried in this order on the solid electrolyte sheet.

(Production of laminate)
Two green sheets of the active material unit were stacked with the solid electrolyte interposed between the active material layers. At this time, the current collector paste layer of the first active material unit extends only to one end surface, and the current collector paste layer of the second active material unit extends only to the other surface, The green sheets of each active material unit were stacked and stacked. Solid electrolyte sheets were stacked on both sides of the green sheets of the stacked active material units so that the total thickness of the stacked green sheets was 500 μm. Thereafter, this was molded using a uniaxial press at a temperature of 80 ° C. and a pressure of 1000 kgf / cm ² [98 MPa]. Next, the laminate block was produced by cutting, and then the laminate block was simultaneously fired to obtain a laminate. In the simultaneous firing, the temperature was increased to a firing temperature of 840 ° C. at a temperature rise rate of 200 ° C./hour in nitrogen, maintained at that temperature for 2 hours, and naturally cooled after firing. The size of the laminate after co-firing was 3.2 mm × 2.5 mm × 0.4 mm.

(Terminal electrode formation process)
A terminal electrode paste was applied to the end face of the laminate. Heat curing was performed at 150 ° C. for 30 minutes to form a pair of terminal electrodes.

(Terminal electrode finish for mounting)
A mask was applied to the surface other than the terminal electrode, and a film was formed on the terminal electrode in the order of Ni, Cu, and Sn to obtain a solid battery.

(Mounting process)
A solid battery was placed on a flexible substrate and soldered. Specifically, the lead-free solder paste was printed on the lands using a metal mask designed for the lands formed on the conductors on the main surface of the flexible substrate. Furthermore, the solid battery was placed on the printed land and passed through a reflow furnace where the atmosphere was replaced with a nitrogen atmosphere. The reflow furnace has three regions with different temperatures, and the substrate and the solid battery disposed thereon were passed in order. The first preheating zone was passed through a furnace at 150 ° C. to 200 ° C. over 300 seconds, and the second main heat zone was 240 ° C. to 270 ° C., which was passed in 60 seconds. The third cooling zone was passed over 600 seconds to lower the temperature to near room temperature.

(Arrangement of Example 1)
In Example 1, the second battery group is arranged 3.5 mm away from the first battery group by a distance of 3.5 mm in the predetermined direction and 2.25 mm perpendicular to the arrangement, and the first battery group and the second battery group are close to each other. The distance between the solid batteries was 1 mm. The distance between the solid batteries constituting the first battery group and the distance between the solid batteries constituting the second battery group were each 4.5 mm. The flexible substrate and the metal mask used were designed based on the arrangement of the solid state battery. The number of batteries constituting each of the first battery group and the second battery group is six, and the first battery group and the second battery group are alternately repeated three times, and a total of 36 solid batteries are mounted on the substrate. did. This obtained the electrical storage apparatus.

(Comparative Example 1)
Comparative Example 1 was produced in the same manner as in Example 1 except for the arrangement of the solid battery and the position of the land on the flexible substrate. In Comparative Example 1, as in the prior art, a total of 36 solid batteries, 3 in the vertical direction and 6 in the horizontal direction, are regularly arranged and mounted in a grid, and the interval between adjacent solid batteries is 1 mm. did.

(Evaluation method for twisting)
One of the short sides of the flexible substrate was fixed, and a durability test against torsion was performed. First, it twisted until the other short side made 90 degree | times with respect to the fixed short side. Next, the twist was returned to the original, and the unfixed short side was twisted by 90 degrees in the opposite direction to the one twisted first. A series of operations was performed once, and this was repeated a plurality of times. A solid battery in which at least one terminal electrode was detached from the flexible substrate or a solid battery in which cracks, cracks, or chips were generated was regarded as defective, and it was visually determined whether or not it was defective.

(Test results)
An endurance test against torsion was performed on Example 1 and Comparative Example 1. Table 1 shows the number of defects with respect to the number of twists in Example 1 and Comparative Example 1.

  From Table 1, it can be seen that the power storage device of Example 1 has higher durability against torsion than Comparative Example 1. This is thought to be because the load between the terminal electrode and the flexible substrate caused by twisting was reduced compared to the conventional arrangement by taking the arrangement of this embodiment.

  As described above, the power storage device and the power storage unit according to the present invention are effective against bending, bending, and twisting. These can be used also in a portion where bending or bending and torsion are expected, and the capacity per mounting area can be optimized, so that it greatly contributes particularly in the field of electronics.

DESCRIPTION OF SYMBOLS 1 Flexible substrate 2 1st battery group 3 2nd battery group 4 Conductor 10 Solid battery 11 Positive electrode layer 12 Negative electrode layer 13 Solid electrolyte layer 14 Positive electrode active material layer 15 Positive electrode collector layer 16 Negative electrode active material layer 17 Negative electrode current collector Body layer 18 Terminal electrode 19 Laminate 20 Sheet-like solar power generation element 50 Power storage device 51 Power storage unit

Claims (5)

A conductive wire extending in a predetermined direction on at least one main surface of the flexible substrate, a first battery group in which a plurality of solid batteries are arranged in parallel in the predetermined direction, and a plurality of solid batteries in the predetermined direction A second battery group arranged and connected in parallel,
The solid battery of the first battery group and the solid battery of the second battery group are arranged at different positions when projected from any of the predetermined direction and the orthogonal direction perpendicular thereto,
The first battery group and the second battery group are connected in series by arranging terminal electrodes having different polarities on the same conducting wire.   When the power storage device is projected from the predetermined direction, a part of the solid state battery of the first battery group and a part of the solid state battery of the second battery group are arranged so as to overlap each other. The power storage device according to claim 1.   The power storage device according to claim 1, wherein the first battery group and the second battery group are alternately arranged in the orthogonal direction.   The electronic device carrying the electrical storage apparatus as described in any one of Claims 1 thru | or 3. A power storage device in which a sheet-like photovoltaic power generation element is bonded to the opposite side of the main surface, and the power storage device according to any one of claims 1 to 4 and the photovoltaic power generation element are electrically connected. unit.

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