JP2010049968A - Solid electrolyte secondary cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve adhesiveness between a negative electrode active material layer containing an alloy-based negative electrode active material and a polymer electrolyte, and maintain output characteristics at a high level even if charge-discharge is repeated in a solid electrolyte secondary battery. <P>SOLUTION: The solid electrolyte secondary battery 1 includes: a battery cell 5 including a positive electrode to contain a positive electrode active material capable of storing and releasing lithium, a negative electrode to contain the alloy-based negative active material, and a solid electrolyte or a separator into which the solid electrolyte is impregnated; a heating means 6 to heat the battery cell 5; a voltage detecting means 7; and a control means 9 to control the battery cell 5 at the time of discharge to become to have a prescribed temperature or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid electrolyte secondary battery. More specifically, the present invention mainly relates to an improvement in adhesion between a negative electrode active material and a solid electrolyte in a solid electrolyte secondary battery.

  Lithium ion secondary batteries are widely used as power sources for various portable electronic devices, for example, because they have high energy density and high output and are relatively easy to downsize. In recent years, research on application to main power supplies, auxiliary power supplies and the like of electric vehicles and hybrid vehicles has been actively conducted. A lithium ion secondary battery includes, for example, a positive electrode containing a positive electrode active material capable of occluding and releasing lithium, a negative electrode containing a negative electrode active material capable of occluding and releasing lithium, a separator, and a liquid nonaqueous electrolyte. Is included.

  A lithium ion secondary battery has excellent performance in terms of safety, but since it contains a liquid nonaqueous electrolyte, it is necessary to prevent leakage of the nonaqueous electrolyte. However, in order to prevent leakage, it is necessary to examine various items such as changes in the shape and material of the battery case, the internal structure of the battery, and the production process. For this reason, the use of solid electrolytes has also been attempted for lithium ion secondary batteries. Examples of the solid electrolyte include a polymer electrolyte obtained by solidifying a nonaqueous electrolyte with a polymer. Since the solid electrolyte is a solid substance and there is no risk of leakage, the degree of freedom in selecting the battery structure, the material of the battery case, etc. is increased, and the production process can be simplified.

  For example, a lithium ion secondary battery including a solid electrolyte (hereinafter referred to as “solid electrolyte secondary battery”) has been proposed (see, for example, Patent Document 1). The solid electrolyte secondary battery of Patent Document 1 includes a positive electrode containing a composite oxide of lithium and a transition metal as a positive electrode active material, and a negative electrode containing an alloy-based negative electrode active material such as silicon or tin oxide as a negative electrode active material. And a polymer electrolyte. Here, the alloy-based negative electrode active material is a substance that occludes lithium by alloying with lithium and reversibly occludes and releases lithium. Since the alloy-based negative active material has a higher capacity than the conventional carbon material-based negative electrode active material, it is possible to expect a higher capacity of the battery. However, the battery of Patent Document 1 has a problem in that output characteristics are rapidly deteriorated with an increase in the number of charge / discharge cycles. At the same time, there is a problem that the life of the battery is shortened.

  Various proposals have been made to improve the adhesion between the active material layer and the polymer electrolyte in the solid electrolyte secondary battery. For example, it has been proposed to use a polymer electrolyte containing a liquid compound and to provide a liquid compound layer between the positive electrode or the negative electrode and the polymer electrolyte (see, for example, Patent Document 2). Here, the liquid compound is one having an alkylene oxide repeating unit.

  However, when an alloy-based negative electrode active material is used for the battery of Patent Document 2, as with the battery of Patent Document 1, the output characteristics are drastically lowered and the battery life is shortened as the number of charge / discharge cycles increases. Further, the alloy-based negative electrode active material has a characteristic of reversibly repeating expansion and contraction of a relatively large volume with charge / discharge. And if an alloy type negative electrode active material expand | swells at the time of charge, it will become difficult to maintain the shape of the layer of a liquid compound. As a result, leakage of the liquid compound to the outside of the battery may occur, and battery performance and battery safety may be reduced.

  In addition, it has been proposed to enhance the adhesion between the active material layer and the polymer electrolyte by bonding the active material layer and the polymer electrolyte via a coupling agent (see, for example, Patent Document 3). Since the coupling agent binds to other substances by a covalent bond or the like, the bond strength at the atomic level is high. However, when the alloy-based negative electrode active material is used in the battery of Patent Document 3, the volume expansion of the alloy-based negative electrode active material cannot be suppressed only by the coupling with the coupling agent. In addition, it is inevitable that the output characteristics are rapidly deteriorated and the life is shortened as the number of times of charging / discharging is increased.

  On the other hand, a secondary battery system including a secondary battery, a heating unit, a temperature detection unit, and a control unit has been proposed (see, for example, Patent Document 4). The secondary battery includes an electrode body having a first proximity portion and a second proximity portion whose temperature is lower than that of the first proximity portion. The heating means heats at least the second proximity portion of the first proximity portion and the second proximity portion. The temperature detecting means detects the temperatures of the first proximity portion and the second proximity portion. The control means controls heating of the first proximity part and the second proximity part by the heating means according to the detection result of the temperature detection means.

  This secondary battery system is mainly intended to prevent a reduction in battery output in cold regions. Therefore, even if it says that it heats, the temperature of a 1st proximity | contact part and a 2nd proximity | contact part is below freezing point, for example as FIG. Further, even when heated to a temperature below the freezing point as described above, the polymer electrolyte is not deformed. Moreover, the secondary battery of patent document 4 is a general lithium ion secondary battery containing a non-aqueous electrolyte, and is not a solid electrolyte secondary battery. Furthermore, Patent Document 4 has no description about heating a solid electrolyte secondary battery containing an alloy-based negative electrode active material.

  Furthermore, a battery control system including a solid electrolyte battery, a temperature sensor, a heating element, a heating element control unit, and a power mode control unit has been proposed (see, for example, Patent Document 5). The temperature sensor detects the temperature of the solid electrolyte battery. The heating element heats the solid electrolyte battery. The heating element control means controls the current supplied to the heating element so as to maintain the cell at a predetermined temperature according to the detection result of the temperature sensor. The power mode control means detects the power demand from the battery, and sets the predetermined temperature according to the level and / or energy amount of power supplied to or from the battery. Moreover, a lithium polymer electrolyte battery is mentioned as a specific example of the solid electrolyte battery.

  In patent document 5, since the operating temperature of a solid electrolyte battery is room temperature or higher, the solid electrolyte battery is heated to attempt to fully exhibit the battery performance inherent in the solid electrolyte battery. However, the heating temperature in Patent Document 5 is 40 ° C. or 60 ° C., and it is difficult to deform the polymer electrolyte at such a heating temperature. Furthermore, heating a general solid electrolyte battery does not extend the battery life. Patent Document 5 also has no description about heating a solid electrolyte secondary battery containing an alloy-based negative electrode active material.

JP 2002-33130 A JP 2006-294605 A JP 2007-305453 A JP 2008-21669 A Special table 2002-509342 gazette

  An object of the present invention is to provide a solid electrolyte secondary battery in which the adhesion between a negative electrode active material layer containing an alloy-based negative electrode active material and a polymer electrolyte is improved, and output characteristics are maintained at a high level even after repeated charge and discharge. It is to be.

  The inventors of the present invention have intensively studied to solve the above problems. In the course of that research, we investigated the causes of solid electrolyte secondary batteries containing alloy-based negative electrode active materials and polymer electrolytes that caused a significant decrease in output characteristics and a decrease in life as the number of charge / discharge cycles increased. I came to such a conclusion.

  That is, the volume of the alloy-based negative electrode active material changes relatively greatly as lithium is occluded and released. On the other hand, since the polymer electrolyte contains a polymer as a main component, it does not easily return to its original shape when deformed under stress. Therefore, when the alloy-based negative electrode active material expands during charging and deforms the polymer electrolyte, the shape of the polymer electrolyte does not return to the original shape even when the alloy-based negative electrode active material contracts during discharge. Therefore, the negative electrode active material layer and the polymer electrolyte Contact with is cut off. For this reason, at the interface between the negative electrode active material layer and the polymer electrolyte, the contact area between the negative electrode active material layer and the polymer electrolyte gradually decreases as the number of charge / discharge cycles increases, and the output characteristics of the battery rapidly decrease. Presumed to be.

  The present inventors have further studied based on such knowledge. As a result, the polymer electrolyte deformed by the volume expansion of the alloy-based negative electrode active material at the time of discharge is restored to its original shape, so that the adhesion between the negative electrode active material layer and the polymer electrolyte is maintained at a high level, and the output characteristics are improved. I got the idea of preventing the decline. As a result of further research based on this idea, the present inventors have come up with a configuration in which the temperature of the solid electrolyte secondary battery during discharge is maintained at a predetermined temperature or higher for a predetermined time.

  According to this configuration, the shape of the polymer electrolyte can be restored without causing leakage of the non-aqueous electrolyte from the polymer electrolyte, deterioration in battery performance, etc., and the output characteristics and the like are at a high level over the entire service life of the battery. It was found that the service life was maintained and the service life was further extended. The present inventor has completed the present invention based on these findings.

That is, the present invention relates to a battery cell including a positive electrode containing a positive electrode active material capable of inserting and extracting lithium, a negative electrode containing an alloy-based negative electrode active material, and a separator impregnated with a solid electrolyte or a solid electrolyte, and a battery during discharge The present invention relates to a solid electrolyte secondary battery including control means for controlling the cell to be at a predetermined temperature or higher.
In one embodiment of the present invention, the battery pack further includes a charge number detection means for detecting the number of times the battery cell is charged, and the control means is configured so that the battery cell at the time of discharge becomes a predetermined temperature or more according to a detection result by the charge number detection means. It is preferable to control.

In another embodiment, the battery pack further includes voltage detection means for detecting an open circuit voltage of the battery cell, and the control means is configured so that the battery cell at the time of discharge becomes equal to or higher than a predetermined temperature according to a detection result by the voltage detection means. It is preferable to control.
In yet another embodiment, the battery pack further includes discharge time integration means for integrating the discharge time of the battery cells, and the control means is configured so that the battery cells at the time of discharge become equal to or higher than a predetermined temperature according to the integration result by the discharge time integration means. It is preferable to control.

  Further, in each of the above-described embodiments, the battery pack further includes a discharge control unit that controls the discharge of the battery cell, and a discharge remaining amount detection unit that detects the remaining discharge amount of the battery cell. According to the detection result, it is preferable to control the discharge control means so that the battery cell discharges the remaining amount of discharge, and after charging the battery cell, it is preferable to control so that the battery cell at the time of discharging becomes a predetermined temperature or higher. .

Further, in each of the above-described embodiments, it is preferable that a heating unit that heats the battery cell is further included, and the control unit controls the heating unit so that the battery cell at the time of discharging becomes a predetermined temperature or higher.
The heating means is preferably a resistor that generates heat when energized or a heat source included in an electrical device or an electronic device.
It is preferable that the heat generation source included in the electric device and the electronic device is a central processing unit.

It is preferable that the solid electrolyte contains a polymer, and the predetermined temperature is a temperature at which the polymer can be deformed.
The predetermined temperature is more preferably 60 ° C. or higher.

The alloy-based negative electrode active material is preferably an alloy-based negative electrode active material containing silicon or tin.
More preferably, the alloy-based negative electrode active material containing silicon is at least one selected from the group consisting of silicon, silicon oxide, silicon nitride, silicon-containing alloy and silicon compound.
More preferably, the alloy-based negative electrode active material containing tin is at least one selected from the group consisting of tin, tin oxide, a tin-containing alloy, and a tin compound.

  The solid electrolyte secondary battery of the present invention has a high capacity and a high output. In addition, the solid electrolyte secondary battery of the present invention maintains a favorable state of adhesion between the negative electrode active material layer and the polymer electrolyte over its entire service life, so the deterioration of charge / discharge cycle characteristics, particularly output characteristics, is extremely high. Very few. In addition, the service life itself is extended.

FIG. 1 is a block diagram showing a simplified configuration of a solid electrolyte secondary battery 1 which is one embodiment of the present invention. FIG. 2 is a vertical cross-sectional view showing a simplified configuration of a main part (battery cell 5) of the solid electrolyte secondary battery 1 shown in FIG.
The solid electrolyte secondary battery 1 includes a battery cell 5, a heating unit 6, a voltage detection unit 7, a charge count detection unit 8, and a control unit 9. The solid electrolyte secondary battery 1 is attached to an external device 10 (not shown) used as an auxiliary power source and connected to a predetermined circuit, and a central processing unit (hereinafter referred to as “CPU”) of the external device 10 is heated. It also serves as means 6. Therefore, the external device 10 is provided with a space for mounting the solid electrolyte secondary battery 1. Further, in the external device 10, a CPU is disposed in the vicinity of the battery cell 5 being mounted.

  As shown in FIG. 2, the battery cell 5 includes a negative electrode 11, a positive electrode 12, a separator 13, a sealing material 14, a negative electrode lead 19a, and a positive electrode lead 19b. In addition, the separator 13 is arrange | positioned between the negative electrode 11 and the positive electrode 12, and the electrode group is comprised. The separator 13 is impregnated with a polymer electrolyte (not shown).

The negative electrode 11 includes a negative electrode current collector 15 and a negative electrode active material layer 16.
The negative electrode current collector 15 can be a porous or non-porous conductive substrate. Examples of the porous conductive substrate include a mesh body, a porous body, and a nonwoven fabric. Examples of the non-porous conductive substrate include a metal foil and a metal plate. Examples of the material for the conductive substrate include copper, copper alloy, nickel, silver, and stainless steel. The thickness of the conductive substrate is not particularly limited, but is usually 1 to 500 μm, preferably 1 to 50 μm, more preferably 10 to 40 μm, and particularly preferably 10 to 30 μm.

The negative electrode active material layer 16 is provided on one or both surfaces in the thickness direction of the negative electrode current collector 15. The negative electrode active material layer 16 contains an alloy-based negative electrode active material as a main component. As the alloy-based negative electrode active material, known materials can be used, and examples thereof include an alloy-based negative electrode active material containing silicon and an alloy-based negative electrode active material containing tin. An alloy type negative electrode active material can be used individually by 1 type, or can be used in combination of 2 or more type.
Examples of the alloy-based negative electrode active material containing silicon include silicon, silicon oxide, silicon nitride, silicon-containing alloy, and silicon compound.

Examples of the silicon oxide include silicon oxide represented by the composition formula: SiO _a (0.05 <a <1.95). Examples of the silicon nitride include silicon nitride represented by the composition formula: SiN _b (0 <b <4/3). Examples of the silicon-containing alloy include an alloy containing silicon and one or more elements selected from the group consisting of Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, and Ti. It is done. As the silicon compound, for example, a part of silicon contained in silicon, silicon oxide, silicon nitride or silicon-containing alloy is B, Mg, Ni, Ti, Mo, Co, Ca, Cr, Cu, Fe, Mn, Examples thereof include compounds substituted with one or more elements selected from the group consisting of Nb, Ta, V, W, Zn, C, N and Sn.

Examples of the alloy-based negative electrode active material containing tin include tin, tin oxide, a tin-containing alloy, and a tin compound.
Examples of the tin oxide include SnO ₂ and silicon oxide represented by a composition formula: SnO _d (0 <d <2). Examples of the tin-containing alloy include a Ni—Sn alloy, a Mg—Sn alloy, a Fe—Sn alloy, a Cu—Sn alloy, and a Ti—Sn alloy. Examples of the tin compound include SnSiO ₃ , Ni ₂ Sn ₄ , and Mg ₂ Sn.
Among these, silicon, tin, silicon oxide, tin oxide and the like are preferable, and silicon, silicon oxide and the like are particularly preferable.

  The negative electrode active material layer 16 can be formed on the surface of the negative electrode current collector 15 according to a known thin film forming method such as sputtering, vapor deposition, or chemical vapor deposition (CVD). The negative electrode active material layer 16 formed by these methods has a content of the alloy-based negative electrode active material of almost 100%, and can be increased in capacity and output. Further, when the thin film forming method is adopted, the thickness of the negative electrode active material layer 16 can be made thinner than before, and therefore, for example, it is easy to cope with downsizing and thinning of portable electronic devices. Therefore, in the present invention, the negative electrode active material layer 16 formed by sputtering, vapor deposition, chemical vapor deposition (CVD), or the like is preferable. The thickness of the negative electrode active material layer is preferably 3 to 20 μm, more preferably 5 to 15 μm.

The positive electrode 12 includes a positive electrode current collector 17 and a positive electrode active material layer 18.
As the positive electrode current collector 17, a porous or non-porous conductive substrate can be used. Examples of the porous conductive substrate include a mesh body, a porous body, and a nonwoven fabric. Examples of the non-porous conductive substrate include a metal foil and a metal plate. Examples of the material of the conductive substrate include stainless steel, aluminum, aluminum alloy, and titanium. The thickness of the conductive substrate is not particularly limited, but is usually 1 to 500 μm, preferably 1 to 50 μm, more preferably 10 to 40 μm, and particularly preferably 10 to 30 μm.

The positive electrode active material layer 18 is provided on one or both surfaces in the thickness direction of the positive electrode current collector 17. The positive electrode active material layer 18 contains a positive electrode active material, and may contain a conductive agent, a binder or the like as necessary.
As the positive electrode active material, those commonly used in the field of lithium secondary batteries can be used, and examples include lithium-containing composite metal oxides, olivine-type lithium salts, chalcogen compounds, and manganese dioxide. Among these positive electrode active materials, lithium-containing composite metal oxides, olivine type lithium salts and the like can be preferably used.

  The lithium-containing composite metal oxide is a metal oxide containing lithium and a transition metal or a metal oxide in which a part of the transition metal in the metal oxide is substituted with a different element. Here, examples of the different element include Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, and B. Mn, Al, Co, Ni, Mg and the like are preferable. One kind or two or more kinds of different elements may be used.

Specific examples of the lithium-containing composite metal oxide include, for example, Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _y Ni _1-y O ₂ , and Li _x Co _y M _1-y O _{z. , Li x Ni 1-y M} y O z, Li x Mn 2 O 4, Li x Mn 2-y M y O 4, LiMPO 4, Li 2 MPO 4 F ( in the respective formulas, M is Na, Mg, It represents at least one element selected from the group consisting of Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, V and B. x = 0 to 1.2, y = 0-0.9, z = 2.0-2.3). Here, x value which shows the molar ratio of lithium increases / decreases by charging / discharging.

Examples of the olivine type lithium salt include LiFePO ₄ . Examples of the chalcogen compound include titanium disulfide and molybdenum disulfide. A positive electrode active material can be used individually by 1 type, or can be used in combination of 2 or more type.

  Examples of the conductive agent include graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black, and conductive properties such as carbon fiber and metal fiber. Examples thereof include fibers, metal powders such as aluminum powder, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and organic conductive materials such as phenylene derivatives. A conductive agent can be used individually by 1 type, or can be used in combination of 2 or more type.

  Examples of the binder include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, and polyacrylic acid. Ethyl, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene butadiene rubber, carboxy Examples include methyl cellulose. Moreover, you may use the polymer electrolyte demonstrated in detail later as a binder. It is preferable to use a polymer electrolyte as the binder because ions can easily reach from the surface of the positive electrode 12 to the deep part. A binder can be used individually by 1 type, or can be used in combination of 2 or more type as needed.

  The positive electrode active material layer 18 can be formed, for example, by applying a positive electrode mixture slurry to the surface of the positive electrode current collector 17, drying it, and rolling it as necessary, whereby the positive electrode 12 is obtained. The positive electrode mixture slurry can be prepared by dissolving or dispersing a positive electrode active material and, if necessary, a conductive agent and a binder in a dispersion medium. As the dispersion medium, for example, dimethylformamide, dimethylacetamide, methylformamide, N-methyl-2-pyrrolidone (NMP), dimethylamine, acetone, cyclohexanone and the like can be used.

As the separator 13, for example, a porous body made of a synthetic resin, a nonwoven fabric, a woven fabric, a mesh body, or the like can be used. As the synthetic resin, those commonly used in the field of solid electrolyte secondary batteries can be used, and among them, polyolefins such as polyethylene and polypropylene are preferable. The porosity of the separator 13 is preferably 35 to 45%. The thickness of the separator 13 is preferably 15 to 25 μm.
The separator 13 is impregnated with a polymer electrolyte. The polymer electrolyte contains a polymer and a supporting salt, and may further contain a nonaqueous solvent.

  As the polymer, those commonly used in the field of solid electrolyte secondary batteries can be used, and examples thereof include oxygen-containing polymers and fluororesins. The oxygen-containing polymer is a polymer containing oxygen atoms having a large electronegativity in the molecule, such as ether oxygen and ester oxygen. When lithium ions are coordinated to oxygen atoms having a high electronegativity, a lithium salt is dissolved in the polymer, and ion conductivity is exhibited while being a solid electrolyte. Thus, the presence of relatively negatively charged ether oxygen or ester oxygen in the polymer is a condition for exhibiting high conductivity.

  As the oxygen-containing polymer, a polymer having an ethylene oxide unit and / or a propylene oxide unit is preferable. Specific examples thereof include polyethylene oxide, polypropylene oxide, and a copolymer of ethylene oxide and propylene oxide. Among these, it is particularly preferable to use a polymer having ether oxygen in the polymer side chain and a reduced chain length. This makes it very easy for lithium ions to move at the negative electrode interface. Examples of the fluororesin include polyvinylidene fluoride (PVDF) and vinylidene fluoride-hexafluoropropylene copolymer.

As the supporting salt, for _{example, LiClO 4, LiBF 4, LiPF} 6, LiAlCl 4, LiSbF 6, LiSCN, LiCF 3 SO 3, LiAsF 6, lithium lower aliphatic carboxylate, LiCl, LiBr, LiI, chloroborane lithium, Four Examples thereof include lithium phenylborate, LiN (CF ₃ SO ₂ ) ₂ , and LiN (C ₂ F ₅ SO ₂ ) ₂ . The supporting salt can be used alone or in combination of two or more.

  As the non-aqueous solvent, those commonly used in the field of lithium ion secondary batteries can be used, and examples thereof include cyclic carbonates, chain carbonates, and cyclic carboxylates. Examples of the cyclic carbonate include propylene carbonate (PC) and ethylene carbonate (EC). Examples of the chain carbonate include diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), and the like. Examples of the cyclic carboxylic acid ester include γ-butyrolactone (GBL) and γ-valerolactone (GVL). A non-aqueous solvent can be used individually by 1 type or in combination of 2 or more types.

  The polymer electrolyte can be prepared according to a known method. For example, the polymer may be dissolved in a non-aqueous solvent, and the obtained polymer solution and the supporting salt may be mixed. The polymer electrolyte can also be prepared by mixing a polymer and a non-aqueous electrolyte and dissolving the polymer in the non-aqueous electrolyte. The nonaqueous electrolyte contains a supporting salt and a nonaqueous solvent. You may melt | dissolve a polymer under a heating as needed.

  The separator 13 is impregnated with a polymer electrolyte by a general method of impregnating a liquid with a solid. For example, a method of immersing the separator 13 in the polymer electrolyte, a method of applying the polymer electrolyte to the separator 13 and the like can be mentioned. At this time, not only the separator 13 but also the negative electrode 11 and the positive electrode 12 are impregnated with the polymer electrolyte, the separator 13 is disposed between the negative electrode 11 and the positive electrode 12 and laminated, and pressurized in the thickness direction under heating, An electrode group may be created.

  Moreover, you may form the polymer electrolyte layer which consists only of a polymer electrolyte, without using the separator 13. FIG. For example, a polymer electrolyte layer is formed on the surface of the negative electrode active material layer 16 by applying a polymer electrolyte to the surface of the negative electrode active material layer 16 and drying it. Further, the polymer electrolyte may be formed into a film shape to produce a polymer electrolyte layer, and this polymer electrolyte layer may be disposed between the negative electrode 11 and the positive electrode 12.

As the sealing material 14, a material commonly used in the battery field can be used. For example, the sealing material which consists of synthetic resin materials is mentioned.
The negative electrode lead 19a has one end connected to the negative electrode current collector 15 and the other end connected to the external connection terminal 5a. For example, a nickel lead can be used for the negative electrode sheet 19a. The positive electrode lead 19b has one end connected to the positive electrode current collector 17 and the other end connected to the external connection terminal 5b. For example, an aluminum lead can be used for the positive electrode lead 19b. The external connection terminals 5a and 5b are arranged so as to be electrically connectable to the corresponding power supply terminals of the external device 10.

  The battery cell 5 is produced as follows, for example. First, the negative electrode 11, the positive electrode 12, and the separator 13 are impregnated with a polymer electrolyte. Next, the separator 13 is disposed between the negative electrode 11 and the positive electrode 12 and laminated. At this time, the sealing material 14 is disposed in a portion where the negative electrode current collector 15 and the positive electrode current collector 17 directly face each other. However, a gap is provided between the sealing material 14 and the laminated portion including the negative electrode active material layer 16, the separator 13, and the positive electrode active material layer 17. Note that when the active material layer is formed on the entire surface of the current collector, the sealing material 14 is not necessarily provided.

  The laminated body is pressurized in the thickness direction while being heated, and dried to produce an electrode group. One end of the negative electrode lead 19 a is connected to the negative electrode current collector 15 of the obtained electrode group, and the positive electrode lead 19 b is connected to the positive electrode current collector 17. The electrode group is housed in a battery case (not shown), and the other ends of the leads 19a and 19b are led out of the battery case from the opening of the battery case and connected to the external connection terminals 5a and 5b. Thereafter, the opening of the battery case is sealed while the inside of the battery case is decompressed. Thereby, the battery cell 5 is produced.

  The battery cell 5 has no restriction | limiting about the structure and form. Specific examples of the configuration include a stacked type, a wound type, and a bipolar type. Specific examples of the form include a flat shape, a coin shape, a cylindrical shape, a square shape, and a laminate shape.

  In this embodiment, the heating means 6 is a CPU of the external device 10 to which the solid electrolyte battery 1 is attached as an auxiliary power source. The solid electrolyte battery 1 is attached to the external device 10 so that the battery cell 5 is positioned in the vicinity of the heating means 6. The heating means 6 is disposed in the vicinity of the battery cell 5, receives the control of the control means 9, and heats the battery cell 5 so as to maintain the temperature of the battery cell 5 at a predetermined temperature or higher during discharging. When the battery cell 5 is being discharged and the control unit 9 determines that the temperature of the battery cell 5 needs to be heated according to the detection result of the charge count detection unit 8, the heating unit 6 Heat is generated by receiving power from a main power source 10 (not shown), and the discharging battery cell 5 in the vicinity thereof is heated to a predetermined temperature or higher.

  Here, the time of discharge of the battery cell 5 means that the battery cell 5 is in a dischargeable state. Except when charging and when charging is required. Further, the CPU of the external device 10 is always in operation by receiving power from the main power supply during the operation of the external device 10 and is in a heat generating state, but the temperature has reached a predetermined temperature for heating the battery cell 5. Absent. In the case of functioning as the heating means 6 of the battery cell 5, a voltage larger than usual is applied, and the amount of generated heat is increased.

  When the battery cell 5 is discharged, the volume of the alloy-based negative electrode active material shrinks, and a gap may be formed between the negative electrode active material layer 16 and the separator 13. However, at this time, by heating the battery cell 5, the polymer electrolyte in the separator 13 has fluidity and is restored to its original shape, and the adhesion between the negative electrode active material layer 16 and the separator 13 is improved during battery assembly. It will be in the same state. As a result, the adhesion between the negative electrode active material layer 16 and the separator 13 is maintained at a high level over a long period of time, and charging / discharging cycle characteristics, particularly a decrease in output is suppressed.

  As described above, the heating means 6 heats the battery cell 5 during discharge to a predetermined temperature or higher. Here, the predetermined temperature is a temperature at which the polymer electrolyte can be deformed, and is appropriately selected from a wide range depending on the type of the polymer electrolyte, and an example thereof is 60 ° C. or higher, preferably 60 to 80 ° C. More preferably, it is 65-75 degreeC. Also, the heating time is appropriately selected from a wide range depending on the heating temperature and the type of polymer electrolyte. For example, the heating time is usually 1 to 15 minutes, preferably 3 to 10 minutes, more preferably 3 to 5 minutes. It is.

  In the present embodiment, a CPU is used as the heating unit 6, but the present invention is not limited thereto, and a heat source other than the CPU included in the electric device and the electronic device can also be used. A resistor that generates heat when energized can also be used. Known resistors can be used as the resistor that generates heat when energized, and examples thereof include a ceramic heater, a nichrome wire heater, a resistance temperature detector, and a surface heating element. Commercially available heaters, thermostats, etc. can also be used. A temperature detection unit (not shown) is arranged in the vicinity of the heating unit 6, and the detection result is output to the control unit 9. The control means 9 adjusts the voltage value applied to the heating means 6 and the voltage application time according to the detection result by the temperature detection means. For example, a temperature sensor can be used as the temperature detection means.

  The voltage detection means 7 measures the open circuit voltage (OCV) of the battery cell 5 at the time of discharging and charging. The detection of OCV by the voltage detection means is performed when the battery cell 5 is discharged at a certain voltage or more for a certain period of time and the discharge is completed. For the voltage control means 7, for example, a voltmeter can be used. The voltage detection means 7 is electrically connected to the control means 9 and outputs the measurement result to the control means 9. The control means 9 determines whether or not the battery cell 5 needs to be charged according to the measurement result by the battery measurement means 7 when the battery is discharged.

  Specifically, it is as follows. The reference value of the OCV of the battery cell 5 is input to the control means 9 in advance. The control means 9 compares the measurement result by the voltage detection means 7 with a reference value, and when the measurement result is lower than the reference value, determines that the battery cell 5 needs to be charged, and displays the determination result (not shown). The user of the external device 10 is notified by means. The user causes the control means 8 to start charging the battery cell 5 by a key operation or the like. Alternatively, the control means 8 automatically sends a control signal to the main power supply of the external device 10 to start charging the battery cell 5. The determination as to whether or not charging by the control means 9 is necessary is performed every time a measurement result is input from the voltage detection means 7. In the present embodiment, the OCV reference value is 3.15V.

  Further, when charging the battery cell 5, the control means 9 determines whether or not to release the charge according to the measurement result by the voltage detection means 7. Specifically, it is as follows. The reference value of the OCV of the battery cell 5 is input to the control means 9 in advance. The control means 9 compares the measurement result by the voltage detection means 7 with the reference value, and when the measurement result is the same as or exceeds the reference value, it is determined that the battery cell 5 needs to be released from charge. Based on the determination result, a control signal is sent to the main power supply of the external device 10 to stop charging the battery cell 5. The determination as to whether or not the charge release by the control means 9 is necessary is performed every time the measurement result is input from the voltage detection means 7. In the present embodiment, the OCV reference value is 4.10V. Details of the control means 9 will be described later.

  The number-of-charges detection means 8 detects the number of times the battery cell 5 is charged. The charge number detection means 8 is included in the control means 9 in this embodiment. The one-time charging is determined that the battery cell 5 needs to be charged from the decrease in the OCV value of the battery cell 5, the charging of the battery cell 5 is started, and the battery cell 5 is fully charged from the OCV value. It is a series of steps until it is determined that the charge release is necessary and the charging is finished. The number-of-charge detection means detects the process as one charge. For example, when charging is terminated in the middle due to disconnection of the charging power source or the like, it is not detected that the number of times of charging is one. Detection of the number of times of charging / discharging by the number-of-charges detecting means 8 is started at the same time as charging of the battery cell 5 is started.

As the control means 9, for example, a CPU can be used. In this embodiment, the CPU is a processing circuit including a microcomputer, an interface, a memory, a timer, and the like. In the present embodiment, the CPU is dedicated to the solid electrolyte secondary battery 1, but is not limited thereto, and is mounted on an electric device, an electronic device, or the like to which the solid electrolyte secondary battery 1 is attached as an auxiliary power source. You may share with CPU which is.
The CPU includes, for example, a storage unit, a calculation unit, and a control unit.

  For example, a program for executing the number-of-charges detection unit 8, a discharge time integration unit, a voltage detection unit, a discharge control unit, and a reference value for executing various controls are input to the storage unit. The reference value is, for example, an OCV value that serves as a reference for charging and releasing the battery cell 5, a charge count that serves as a reference for heating the battery cell 5 by the heating means 6, a discharge time, and an open circuit of the battery cell 5. Such as voltage. Further, the storage unit also receives detection results by the charge number detection means, voltage detection means, and the like, integration results by the discharge time integration means, and the like.

  In addition, although all the charge number detection means 8, the discharge time integration means, the voltage detection means, etc. may be executed, at least one of them may be executed. In the present embodiment, only the charge number detection means 8 is executed. Various memories that are commonly used in this field can be used as the storage unit, such as a read only memory (ROM), a random access memory (RAM), a semiconductor memory, and a nonvolatile flash memory.

  As described above, the control means 9 is a CPU including a storage unit, a calculation unit, and a control unit in the present embodiment. Further, in the present embodiment, it is determined whether or not to heat the battery cell 5 at the time of discharging by the heating unit 6 according to the detection result (the number of charging times of the battery cell 5) by the charging number detection unit 8. A reference value for the number of charge / discharge cycles is input to the storage unit of the control means 9. The reference value is set in advance by experiment for each capacity of the battery cell 5, and is input to the storage unit as a data table. The capacity of the battery cell 5 is determined by the control means 9 based on the highest OCV value at the time of discharging. In addition, the detection result by the charge number detection means 8 is input to the storage unit of the control means 9. This detection result is updated when a new detection result is input.

  In the calculation part of the control means 9, the detection result by the number-of-charges detection means 8 is compared with a reference value, and when the detection result is equal to or exceeds the reference value, the battery cell 5 needs to be heated. Is determined. When the detection result is smaller than the reference value, it is determined that heating of the battery cell 5 is unnecessary. The calculation unit outputs a determination result that the battery cell 5 needs to be heated to the control unit of the control means 9. The control unit sends a control signal to the main power supply of the external device 10 according to the determination result that the battery cell 5 needs to be heated, and starts applying the voltage to the heating unit 6. Whether or not the battery cell 5 needs to be heated by the control unit 9 is determined every time the detection result by the charge number detection unit 8 is updated in the storage unit.

  As described above, the temperature of the heating unit 6 and the adjustment of the heating are performed using a temperature detection unit (not shown) disposed in the vicinity of the heating unit 6. In the storage unit of the control means 9, the relationship between the capacity of the battery cell 5, the heating temperature and the heating time is input in advance as a data table. Further, the relationship between the capacity of the battery cell 5 and the maximum value of the OCV at the time of discharging is input in advance as a data table. These data tables are obtained by experiments. In these data tables, the battery capacities are preferably classified with a range. Furthermore, the detection result by the temperature detection means is input to the storage unit of the control means 9.

  The calculation unit of the control means 9 first determines the capacity of the battery cell 5 from the maximum value of the OCV when the battery cell 5 is discharged. This determination is performed until the first charge of the battery cell 5 is performed after the solid electrolyte secondary battery 1 is mounted on the external device 10. Next, the calculation unit compares the reference value corresponding to the capacity of the battery cell 5 with the detection result by the temperature detection means, and determines the magnitude relationship between the reference value and the detection result. If the detection result is lower than the reference value, the determination result is output to the control unit, and the control unit sends a control signal to the main power supply to increase the applied voltage. Even when the detection result is higher than the reference value, the determination result is output to the control unit, and the control unit sends a control signal to the main power supply so as to lower the applied voltage. This determination is performed when the detection result is different from the reference value.

  Moreover, the control means 9 complete | finishes the heating of the battery cell 5 by the heating means 6 after predetermined time progress according to the data table which shows the relationship between the capacity | capacitance of the battery cell 5, heating temperature, and heating time. Thereby, the adhesiveness between the separator 13 and the negative electrode active material layer 16 in the battery cell 5 is recovered, the capacity of the battery cell 5 can be prevented from being reduced, and the useful life of the battery cell 5 can be extended.

  According to the present embodiment, since the voltage detection means 7 exists separately from the control means 9, the control means 9 includes a CPU incorporated in the electric and electronic devices to which the solid electrolyte secondary battery 1 is attached. There is an advantage that it is easy to use. In other words, since it is not necessary to program the detection means inside the CPU, it is not necessary to change the CPU of the electronic and electrical devices greatly according to the mounting of the solid electrolyte secondary battery 2, and it is possible to cope with the minimum change. become.

  In the present embodiment, the battery cell 5 is heated to a predetermined temperature or higher by the heating means 6 in accordance with the detection result of the charge number detection means 8, but the present invention is not limited to this. For example, the detection result of the voltage detection means 7 is May be used. A relationship between the capacity of the battery cell 5 and the reference OCV value is input to the storage unit of the control unit 9 as a data table. The data table is obtained by experiment. Here, based on the reference OCV value, the calculation unit of the control means 9 determines whether or not the battery cell 5 needs to be heated. Moreover, the detection result of the voltage detection means 7 is input. The detection result in the storage unit is updated each time a new detection result is input.

  The calculation part of the control part 9 determines the magnitude of the detection result by the voltage detection means 7 and the reference OCV value. This determination is performed every time the detection result of the voltage detection means 7 is updated in the storage unit regardless of whether or not the battery cell 5 is being heated. The calculation unit determines that the battery cell 5 needs to be heated when the detection result by the voltage detection unit 7 is lower than the reference OCV value, and outputs the determination result to the control unit. Further, when the detection result by the voltage detection means 7 is equal to or higher than the reference OCV value, the calculation unit determines that the battery cell 5 does not need to be heated. At this time, if the battery cell 5 is being heated, a determination result that the battery cell 5 does not need to be heated is output to the control unit.

  The controller 9 outputs a control signal to the main power supply of the external device 10 according to the determination result that the battery cell 5 needs to be heated, and controls voltage application from the main power supply to the heating means 6. Further, the control unit outputs a control signal to the main power supply of the external device 10 according to the determination result that the battery cell 5 does not need to be heated, and stops the voltage application from the main power supply to the heating means 6. Also at this time, the temperature control of the heating means 6 is performed. Although the temperature control of the heating means 6 can be performed in the same manner as described above, it is preferable to use only the relationship between the battery capacity and the heating temperature in the data table. Thereby, the effect similar to the control based on the detection result of the voltage detection means 7 is acquired. Instead of the voltage detection means 7, a voltage detection means may be provided inside the control unit 9 and the same control may be performed.

  Moreover, it can replace with the detection result by the charge frequency detection means 8, and can heat the battery cell 5 using the detection result by a discharge time integration means. The discharge time integrating means is included in the control unit 9. The discharge time integration means detects and integrates the time from the start of discharge to the end of discharge every time the battery cell 5 is discharged at a predetermined voltage or higher. In the present embodiment, for example, the predetermined voltage is 2.5V.

  The integration result is input to the storage unit. The integration result is updated by adding a new integration result each time the battery cell 5 is discharged. That is, the integration result is added until the battery cell 5 is heated. The integration result is reset every time the heating of the battery cell 5 is completed. In addition, a reference value for the discharge time is input in advance in the storage unit. That is, the relationship between the capacity of the battery cell 5 and the corresponding accumulated time is input as a data table. The data table is obtained by experiment.

  The calculation unit compares the integration result obtained by the discharge time integration means with the reference value of the discharge time, and determines whether or not the battery cell 5 needs to be heated. This determination is performed every time the integration result is updated. In addition, determination is not implemented when an integration result is updated under the heating of the battery cell 5. The arithmetic unit determines that the battery cell 5 is not heated when the integration result is less than the reference value of the discharge time, and ends the determination operation at that time. In addition, when the integration result is equal to or exceeds the reference value of the discharge time, the calculation unit determines that the battery cell 5 needs to be heated, and outputs the determination result to the control unit.

  The control unit heats the battery cell 5 by the heating unit 6 in the same manner as the heating of the battery cell 5 according to the detection result of the charge number detection unit 8. At this time, the temperature control of the heating means 6 is similarly performed. After the heating of the battery cell 5 is completed, the integration result input to the storage unit is reset. Alternatively, a total integration result obtained by further integrating all integration results is written in the storage unit, and the heating time and / or heating temperature by the heating means 6 of the battery cell 5 is increased as the total integration result increases. May be performed. Further, as the total integration result increases, the integration time that is a reference for heating the battery cell 5 may be gradually reduced.

  The discharge control means is configured to heat the battery cell 5 before heating the battery cell 5 when it is determined that the battery cell 5 needs to be heated based on the detection result or the integration result of the charge number detection means 8, the voltage detection means 7 or the discharge time integration means. The battery cell 5 is forcibly discharged. Thereby, the heating effect of the battery cell 5 further improves, and the degree of recovery of the battery performance further increases. More specifically, for example, it is carried out to widen the gap between the active materials and effectively re-impregnate the solid electrolyte between the active materials. The discharge control means is included in the control means 9.

  A reference OCV value for determining whether or not the battery cell 5 is in a fully discharged state is input in advance in the storage unit of the control unit 9. Specifically, the relationship between the capacity of the battery cell 5 and the OCV value in the fully discharged state is input as a data table. The data table is obtained in advance by experiments. When the calculation unit of the control unit 9 determines that the battery cell 5 needs to be heated based on the detection result or the integration result, the calculation unit detects the OCV of the battery cell 5 and the battery cell 5 is in a fully discharged state from the detection result. It is determined whether or not.

  When the battery cell 5 is in a completely discharged state, the determination result that the battery cell 5 needs to be heated is output to the control unit, and the battery cell 5 is heated. On the other hand, when the battery cell 5 is not in the complete discharge state, the discharge control means is operated to forcibly discharge the battery cell 5 until the battery cell 5 is in the complete discharge state. Then, the determination result that the battery cell 5 needs to be heated is output to the control unit, and the battery cell 5 is heated. Thereby, the battery cell 5 is effectively heated, and the surface of the separator 13 and the surface of the negative electrode active material layer 16 are more closely adhered.

  By periodically heating the battery cell 5 as described above, the adhesion state between the separator 13 (or the polymer electrolyte layer) and the surface of the negative electrode active material layer 16 becomes the initial state of use of the solid electrolyte secondary battery 1. Recover. As a result, the battery performance of the solid electrolyte secondary battery 1, for example, the charge / discharge cycle characteristics (particularly the output characteristics) is restored to a state close to the initial use, and the deterioration of the battery performance is remarkably suppressed.

  FIG. 3 is a block diagram showing a simplified configuration of a solid electrolyte secondary battery 2 according to another embodiment. The solid electrolyte secondary battery 2 is similar to the solid electrolyte secondary battery 1, and corresponding portions are denoted by the same reference numerals as in FIG. 1 and description thereof is omitted. The solid electrolyte secondary battery 2 has the same configuration as that of the solid electrolyte secondary battery 1 except that the voltage detection means 8 is included.

  The solid electrolyte secondary battery 2 has a heating means 6a inside, and the other configuration is the same as that of the solid electrolyte secondary battery 1. For the heating means 6a, for example, a resistor that generates heat when energized can be used. Known resistors can be used as the resistor that generates heat when energized, and examples thereof include a ceramic heater, a nichrome wire heater, a resistance temperature detector, and a surface heating element. Under the control of the control unit 7, the heating unit 6a receives a voltage from a main power source of an external device 10 (not shown) on which the solid electrolyte secondary battery 2 is mounted and generates heat.

  Also in the solid electrolyte secondary battery 2, as in the solid electrolyte secondary battery 1, the voltage detection means 7 detects the OCV value of the battery cell 5, and based on the detection result, the control means 9 The necessity of heating is determined and the battery cell 5 is heated according to the determination result. The determination operation and the heating control operation by the heating means 6 a are the same as those in the solid electrolyte secondary battery 1. Instead of the voltage detection means 7, a charge count detection means, a discharge time integration means, and the like may be provided. Further, a discharge control means may be provided.

  FIG. 4 is a longitudinal sectional view schematically showing the configuration of the negative electrode 20 used in the present invention. FIG. 5 is a perspective view schematically showing the configuration of the negative electrode current collector 21 included in the negative electrode 20 shown in FIG. FIG. 6 is a longitudinal sectional view schematically showing the configuration of the columnar body 25 included in the negative electrode active material layer 23 of the negative electrode 20 shown in FIG. FIG. 7 is a side view schematically showing the configuration of the electron beam evaporation apparatus 30 for producing the columnar body 25.

The negative electrode 20 includes a negative electrode current collector 21 and a negative electrode active material layer 23.
As shown in FIG. 5, the negative electrode current collector 21 is characterized in that a plurality of convex portions 22 are provided on both or one of the surfaces in the thickness direction.

  The convex portion 22 is a protrusion provided so as to extend from the surface 21 a in the thickness direction of the negative electrode current collector 21 (hereinafter simply referred to as “surface 21 a”) toward the outside of the negative electrode current collector 21. The height of the convex portion 22 is the length from the surface 21a to the portion (the most advanced portion) farthest from the surface 21a of the convex portion 22 in the direction perpendicular to the surface 21a on which the convex portion 22 is formed. That's it. The height of the convex portion 22 is not particularly limited, but is preferably formed such that the average height is about 3 to 10 μm. Moreover, although the cross-sectional diameter in the direction parallel to the surface 21a of the convex part 22 is not specifically limited, For example, it is 1-50 micrometers.

  The average height of the protrusions 22 is obtained by, for example, observing the cross section of the current collector 1 in the thickness direction of the negative electrode current collector 21 with a scanning electron microscope (SEM). It can be determined by measuring and calculating an average value from the measured values obtained. Both the convex portion 22 and the cross-sectional diameter can be measured in the same manner as the height of the convex portion 22. Note that the plurality of convex portions 22 do not have to be formed with the same height or the same cross-sectional diameter.

  The convex portion 22 has a substantially planar top at the tip portion in the growth direction. The growth direction is a direction from the surface 21 a toward the outside of the negative electrode current collector 21. Since the convex portion 22 has a flat top at the tip portion, the bondability between the convex portion 22 and the columnar body 25 is improved. In order to increase the bonding strength, it is more preferable that the flat surface of the tip portion is substantially parallel to the surface 21a.

  The shape of the convex part 22 is circular in this Embodiment. The shape of the convex part 22 here is the convex part as viewed from above in the vertical direction when the current collector 21 is placed so that the surface opposite to the surface 21a of the negative electrode current collector 21 coincides with the horizontal plane. 22 shape. In addition, the shape of the convex part 22 is not limited to circular, For example, a polygon, an ellipse, etc. may be sufficient. The polygon is preferably a triangle to an octagon in view of manufacturing costs and the like. Furthermore, a parallelogram, trapezoid, rhombus, etc. may be used.

The number of the protrusions 22 and the spacing between the protrusions 22 are not particularly limited, depending on the size of the protrusions 22 (height, cross-sectional diameter, etc.), the size of the columnar body 25 provided on the surface of the protrusions 22 and the like. Are appropriately selected. If an example of the number of the convex parts 22 is shown, it is about 10,000 to 10 million pieces / cm ² . Moreover, it is preferable to form the convex portions 22 so that the distance between the axes of the adjacent convex portions 22 is about 2 to 100 μm.

  A protrusion (not shown) may be formed on the surface of the convex portion 22. As a result, for example, the bondability between the convex portion 22 and the columnar body 25 is further improved, and peeling of the columnar body 25 from the convex portion 22 and peeling propagation are more reliably prevented. The protrusion is provided so as to protrude from the surface of the protrusion 22 to the outside of the protrusion 22. A plurality of protrusions having a size smaller than that of the protrusion 22 may be formed. Further, the protrusion may be formed on the side surface of the convex portion 22 so as to extend in the circumferential direction and / or the growth direction of the convex portion 22. Moreover, when the convex part 22 has the planar top part in the front-end | tip part, 1 or several protrusion smaller than the convex part 22 may be formed in a top part, and also 1 or several extended long in one direction The protrusion may be formed on the top.

  The negative electrode current collector 21 can be manufactured using a technique for forming irregularities on a metal foil, a metal sheet, or the like, for example. Specifically, for example, a roll having a concave portion corresponding to the shape, size, and arrangement of the convex portion 22 (hereinafter referred to as a “convex portion roll”) is used. When the convex portion 22 is formed on one side of a metal sheet (including a metal foil) suitable for the negative electrode current collector 21, the convex portion roll and the smooth surface roll are pressed against each other so that the respective axes are parallel to each other. Then, the metal sheet may be passed through the pressure contact portion and pressure-molded. In this case, at least the surface of the roll having a smooth surface is preferably formed of an elastic material.

  In addition, in order to form the convex portions 22 on both surfaces of the metal sheet, two rolls for convex portions are press-contacted so that their respective axes are parallel, and the metal sheet is passed through the press-contact portion and pressed. That's fine. Here, the pressure of the roll is appropriately selected according to the material of the metal sheet, the thickness, the shape and dimensions of the convex portion 22, the set value of the thickness of the metal sheet after pressure molding, that is, the negative electrode current collector 21, and the like.

  The convex part roll can be manufactured, for example, by forming a concave part having a shape, size, and arrangement corresponding to the convex part 22 at a predetermined position on the surface of the ceramic roll. Here, as a ceramic roll, what contains a core roll and a thermal spray layer is used, for example. As the core roll, for example, a roll made of iron, stainless steel, or the like can be used. The sprayed layer is formed by uniformly spraying a ceramic material such as chromium oxide on the surface of the core roll. A recess is formed in the sprayed layer. For forming the recess, for example, a general laser used for forming a ceramic material or the like can be used.

  Another aspect of the convex roll includes a core roll, a base layer, and a thermal spray layer. The core roll is the same as the core roll of the ceramic roll. The underlayer is formed on the surface of the core roll. A concave portion corresponding to the convex portion 22 is formed on the surface of the base layer. In order to form a recess in the underlayer, for example, a resin sheet having a recess on one side is formed, and the surface of the resin sheet opposite to the surface on which the recess is formed is wound around the core roll surface and bonded. . Here, as the synthetic resin, those having high mechanical strength are preferable, for example, thermosetting resins such as unsaturated polyester, thermosetting polyimide, epoxy resin and fluororesin, and thermoplastic resins such as polyamide and polyether ether ketone. Can be mentioned. The sprayed layer is formed by spraying a ceramic material such as chromium oxide along the surface irregularities of the underlayer. Accordingly, the concave portion formed in the underlayer is formed larger by the layer thickness of the thermal spray layer than the design dimension in consideration of the layer thickness of the thermal spray layer.

  Another embodiment of the convex roll includes a core roll and a cemented carbide layer. The core roll is the same as the core roll of the ceramic roll. The cemented carbide layer is formed on the surface of the core roll and includes a cemented carbide such as tungsten carbide. The cemented carbide layer can be formed by shrink fitting a cemented carbide formed in a cylindrical shape onto the core roll. The shrink fitting of the cemented carbide layer is to warm and expand the cylindrical cemented carbide and fit it to the core roll. The cold fitting of the cemented carbide layer means that the core roll is cooled and contracted and inserted into a cemented carbide cylinder. A concave portion corresponding to the convex portion 22 is formed on the surface of the cemented carbide layer by, for example, laser processing.

  In another form of the convex roll, concave portions corresponding to the convex portions 22 are formed on the surface of the hard iron-based roll, for example, by laser processing. A hard iron-type roll is used for rolling manufacture of metal foil, for example. Examples of the hard iron roll include a roll made of high-speed steel, forged steel, or the like. High-speed steel is an iron-based material that has been added with a metal such as molybdenum, tungsten, or vanadium and heat treated to increase its hardness. Forged steel is a steel ingot made by casting a steel in a mold or a steel piece produced from the steel ingot, forged with a press and hammer, or forged by rolling and forging. It is an iron-based material manufactured by heat treatment.

  Further, the one or more protrusions on the surface of the convex portion 22 can be formed, for example, by forming a resist pattern on the surface of the convex portion 22 by a photoresist method and performing metal plating according to the pattern. The protrusions can also be formed by forming the protrusions 22 with dimensions larger than the design dimensions and removing a predetermined portion of the surface of the protrusions 22 by an etching method. A method combining a photoresist method and a plating method can also be used for forming the convex portions 22 themselves.

  As shown in FIGS. 4 and 6, the negative electrode active material layer 23 is preferably formed as an aggregate of a plurality of columnar bodies 25 extending from the surface of the convex portion 22 toward the outside of the negative electrode current collector 21. The columnar body 25 extends in a direction perpendicular to the surface 21a of the negative electrode current collector 21 or with an inclination with respect to the perpendicular direction. Further, since the plurality of columnar bodies 25 are separated from each other with a gap between adjacent columnar bodies 25, stress due to expansion and contraction during charge / discharge is relieved, and the negative electrode active material layer 23 It becomes difficult to peel off from the convex part 22, and deformation of the negative electrode current collector 21 hardly occurs.

  As shown in FIG. 6, the columnar body 25 is more preferably formed as a columnar body formed by laminating eight columnar chunks 25a, 25b, 25c, 25d, 25e, 25f, 25g, and 25h. When forming the negative electrode active material layer 23, first, the columnar lump 25a is formed so as to cover the top of the convex portion 22 and a part of the side surface subsequent thereto. Next, the columnar chunk 25b is formed so as to cover the remaining side surface of the convex portion 22 and a part of the top surface of the columnar chunk 25a. That is, in FIG. 6, the columnar chunk 25 a is formed at one end including the top of the convex portion 22, and the columnar chunk 25 b partially overlaps the columnar chunk 25 a, but the remaining portion is the other portion of the convex portion 22. Formed at the end.

  Further, the columnar chunk 25c is formed so as to cover the rest of the top surface of the columnar chunk 25a and a part of the top surface of the columnar chunk 25b. That is, the columnar chunk 25c is formed so as to mainly contact the columnar chunk 25a. Further, the columnar lump 25d is formed so as to mainly contact the columnar lump 25b. In the same manner, the columnar body 25 is formed by alternately stacking the columnar chunks 25e, 25f, 25g, and 25h. In addition, the number of stacked columnar blocks is not limited to 8, and can be any number of 2 or more.

  The negative electrode active material layer 23 can be formed by, for example, an electron beam evaporation apparatus 30 shown in FIG. In FIG. 7, each member inside the vapor deposition apparatus 30 is also shown by a solid line. The vapor deposition apparatus 30 includes a chamber 31, a first pipe 32, a fixing base 33, a nozzle 34, a target 35, an electron beam generator (not shown), a power source 36, and a second pipe (not shown). The chamber 31 is a pressure-resistant container-like member having an internal space, and the first pipe 32, the fixing base 33, the nozzle 34, and the target 35 are accommodated therein. The first pipe 32 has one end connected to the nozzle 34 and the other end extending outward from the chamber 31 and is connected to a source gas cylinder or source gas manufacturing apparatus (not shown) via a mass flow controller (not shown). Examples of the source gas include oxygen and nitrogen. The first pipe 32 supplies the raw material gas to the nozzle 34.

  The fixing base 33 is a plate-like member, is rotatably supported, and is provided so that the negative electrode current collector 21 can be fixed to one surface in the thickness direction. The rotation of the fixing base 33 is performed between a position indicated by a solid line and a position indicated by a one-dot broken line in FIG. The position indicated by the solid line is that the surface of the fixed base 33 on the side where the negative electrode current collector 21 is fixed faces the nozzle 34 vertically below, and the angle formed by the fixed base 33 and the horizontal straight line is α °. It is a certain position. The position indicated by the one-dot broken line is such that the surface of the fixed base 33 on the side where the negative electrode current collector 21 is fixed faces the nozzle 34 vertically downward, and the angle formed by the fixed base 33 and the horizontal straight line is (180 It is a position that is −α) °. The angle α ° can be appropriately selected according to the dimensions of the columnar body 25 to be formed.

  The nozzle 34 is provided between the fixed base 33 and the target 35 in the vertical direction, and one end of the first pipe 32 is connected thereto. The nozzle 34 mixes the vapor of the alloy-based negative electrode active material rising upward in the vertical direction from the target 35 and the raw material gas supplied from the first pipe 32, and is fixed to the surface of the fixed base 33. It is supplied to the body 21 surface. The target 35 accommodates an alloy-based negative electrode active material or its raw material. The electron beam generator irradiates the alloy-based negative electrode active material accommodated in the target 35 or its raw material with an electron beam and heats it to generate these vapors. The power source 36 is provided outside the chamber 31 and is electrically connected to the electron beam generator, and applies a voltage for generating the electron beam to the electron beam generator. The second pipe introduces a gas that becomes the atmosphere in the chamber 31. An electron beam vapor deposition apparatus having the same configuration as the vapor deposition apparatus 30 is commercially available from ULVAC, Inc., for example.

  According to the electron beam evaporation apparatus 30, first, the negative electrode current collector 21 is fixed to the fixing base 33, and oxygen gas is introduced into the chamber 31. In this state, the target 35 is irradiated with an electron beam to heat the alloy-based negative electrode active material or its raw material to generate its vapor. In the present embodiment, silicon is used as the alloy-based negative electrode active material. The generated steam rises upward in the vertical direction, and when it passes through the nozzle 34, it is mixed with the raw material gas, and then rises and is supplied to the surface of the negative electrode current collector 21 fixed to the fixed base 33. A layer containing silicon and oxygen is formed on the surface of the protrusions 22 that are not.

  At this time, the columnar block 25a shown in FIG. 6 is formed on the surface of the convex portion by disposing the fixing base 33 at the position of the solid line. Next, the fixed base 33 is rotated to the position indicated by the one-dot broken line, whereby the columnar block 25b shown in FIG. 6 is formed. By alternately rotating the position of the fixing base 33 in this way, the columnar body 25 that is a stacked body of the eight columnar lumps 25a, 25b, 25c, 25d, 25e, 25f, 25g, and 25h shown in FIG. 6 is formed. Then, the negative electrode active material layer 23 is formed.

When the alloy-based negative electrode active material is a silicon oxide represented by, for example, SiO _a (0.05 <a <1.95), a columnar shape is formed so that an oxygen concentration gradient can be formed in the thickness direction of the columnar body 25. The body 25 may be formed. Specifically, the oxygen content may be increased at a portion close to the current collector 21, and the oxygen content may be reduced as the distance from the current collector 21 increases. Thereby, the bondability between the convex portion 22 and the columnar body 25 can be further improved.
In the case where the source gas is not supplied from the nozzle 34, the columnar body 25 whose main component is silicon or tin is formed.

Hereinafter, the present invention will be described in detail with reference to Examples, Comparative Examples and Test Examples. In addition, each operation in an Example and a comparative example was implemented in the atmosphere by which dew point management was all -30 degrees C or less.
Example 1
(1) Preparation of positive electrode active material Cobalt sulfate and aluminum sulfate were added to a NiSO ₄ aqueous solution so that Ni: Co: Al = 7: 2: 1 (molar ratio), and the metal ion concentration was 2 mol / L. An aqueous solution of was prepared. While stirring this aqueous solution, a 2 mol / L sodium hydroxide solution was gradually added and neutralized to neutralize a ternary precipitate having a composition represented by Ni _0.7 Co _0.2 Al _0.1 (OH) _2. It was produced by a sedimentation method. This precipitate was separated by filtration, washed with water, and dried at 80 ° C. to obtain a composite hydroxide. As a result of measuring the average particle diameter of the obtained composite hydroxide with a particle size distribution meter (trade name: MT3000, manufactured by Nikkiso Co., Ltd.), the average particle diameter was 10 μm.

This composite hydroxide was heated in the atmosphere at 900 ° C. for 10 hours for heat treatment to obtain a ternary composite oxide having a composition represented by Ni _0.7 Co _0.2 Al _0.1 O. Here, lithium hydroxide monohydrate is added so that the sum of the number of atoms of Ni, Co, and Al is equal to the number of atoms of Li, and heat treatment is performed by heating at 800 ° C. for 10 hours in the air. Thus, a lithium nickel-containing composite metal oxide having a composition represented by LiNi _0.7 Co _0.2 Al _0.1 O ₂ was obtained. As a result of analyzing this lithium nickel-containing composite metal oxide by powder X-ray diffraction, it was confirmed that it had a single-phase hexagonal layered structure and that Co and Al were in solid solution. Thus, a positive electrode active material having an average secondary particle size of 10 μm and a specific surface area by the BET method of 0.45 m ² / g was obtained.

(2) Production of positive electrode 100 g of the positive electrode active material powder obtained above, 3 g of acetylene black (conductive agent), 3 g of polyvinylidene fluoride powder (binder) and 50 ml of N-methyl-2-pyrrolidone (NMP) To prepare a positive electrode mixture paste. This positive electrode mixture paste was applied to one side of an aluminum foil (positive electrode current collector) having a thickness of 20 μm, dried and rolled to form a positive electrode active material layer. Thereafter, the positive electrode was cut out to a size of 30 mm × 180 mm. In the obtained positive electrode, the positive electrode active material layer carried on one side of the aluminum foil had a thickness of 60 μm and a size of 30 mm × 180 mm. A positive electrode lead was connected to the surface of the aluminum foil opposite to the surface on which the positive electrode active material layer was formed.

(3) Production of Negative Electrode FIG. 8 is a side view schematically showing the configuration of the vapor deposition apparatus 40 for forming the negative electrode active material layer. The vapor deposition apparatus 40 includes a vacuum chamber 41, a current collector transport means 42, a source gas supply means 48, a plasma generation means 49, silicon targets 50a and 50b, a shielding plate 51, and an electron beam heating means (not shown). The vacuum chamber 1 is a pressure-resistant container having an internal space that can be depressurized. In the internal space, the current collector transport means 42, the source gas supply means 48, the plasmarization means 49, the silicon targets 50a and 50b, the shielding plate 51, and Houses electron beam heating means.

  The current collector conveying means 42 includes an unwinding roller 43, a can 44, a take-up roller 45, and conveying rollers 46 and 47. The unwinding roller 43, the can 44, and the conveying rollers 46 and 47 are provided so as to be rotatable around the axis. A long negative electrode current collector 21 is wound around the unwinding roller 43. The can 44 has a larger diameter than the other rollers, and includes a cooling means (not shown) therein. When the negative electrode current collector 21 is conveyed on the surface of the can 44, the negative electrode current collector 21 is also cooled. Thereby, the vapor | steam of an alloy type negative electrode active material cools and precipitates, and a thin film is formed.

  The take-up roller 45 is provided so as to be rotatable around its axis by a driving means (not shown). One end of the negative electrode current collector 21 is fixed to the take-up roller 45, and the take-up roller 45 rotates, so that the negative electrode current collector 21 passes from the take-out roller 43 through the transport roller 46, the can 44 and the transport roller 47. Are transported. Then, the negative electrode current collector 21 having a surface on which a thin film of an alloy-based negative electrode active material is formed is wound around the winding roller 45.

  The source gas supply means 48 supplies source gases such as oxygen and nitrogen into the vacuum chamber 41 when forming a thin film mainly composed of silicon or tin oxide, nitride or the like. The plasmar 49 converts the source gas supplied by the source gas supply unit 48 into plasma. The silicon targets 50a and 50b are used when forming a thin film containing silicon. The shielding plate 51 is provided so as to be movable in the horizontal direction below the can 43 in the vertical direction and above the silicon targets 50a and 50b. The horizontal position of the shielding plate 51 is appropriately adjusted according to the thin film formation state on the surface of the negative electrode current collector 21. The electron beam heating means irradiates and heats the silicon targets 50a and 50b with an electron beam to generate silicon vapor.

Using the vapor deposition device 40, a negative electrode active material layer (here, a silicon thin film) having a thickness of 5 μm was formed on the surface of the negative electrode current collector 21 under the following conditions.
Pressure in the vacuum chamber 41: 8.0 × 10 ⁻⁵ Torr
Negative electrode current collector 21: electrolytic copper foil having a length of 50 m, a width of 10 cm, and a thickness of 35 μm (manufactured by Furukawa Circuit Foil Co., Ltd.)
Winding speed of the negative electrode current collector 21 by the winding roller 45 (conveying speed of the negative electrode current collector 21): 2 cm / min

Source gas: Not supplied.
Target 50a, 50b: Silicon single crystal of purity 99.9999% (manufactured by Shin-Etsu Chemical Co., Ltd.)
Electron beam acceleration voltage: -8 kV
Electron beam emission: 300 mA

  The obtained negative electrode was cut into 35 mm × 185 mm to prepare a negative electrode plate. About this negative electrode plate, lithium metal was vapor-deposited on the surface of the negative electrode active material layer (silicon thin film). By depositing lithium metal, lithium corresponding to the irreversible capacity stored in the negative electrode active material layer at the time of the first charge / discharge was supplemented.

  Lithium metal was deposited using a resistance heating vapor deposition apparatus (manufactured by ULVAC, Inc.) in an argon atmosphere. Lithium metal is loaded into a tantalum boat in a resistance heating vapor deposition apparatus, the negative electrode is fixed so that the negative electrode active material layer faces the tantalum boat, and a 50 A current is passed through the tantalum boat in an argon atmosphere. Deposition was performed for 10 minutes. Thus, a negative electrode plate used in the present invention was obtained. A negative electrode lead was connected to the surface of the negative electrode plate where the negative electrode active material layer was not formed.

(4) Preparation of polymer electrolyte LiPF ₆ was dissolved at a concentration of 1.0 mol / L in a mixed solvent containing ethylene carbonate (EC) and propylene carbonate (PC) at a volume ratio of 1: 1, and nonaqueous electrolysis was performed. A liquid was prepared. PVDF was added to this non-aqueous electrolyte and heated to 80 ° C. to prepare a polymer electrolyte which was a 15 wt% solution of PVDF.

(5) Production of solid electrolyte secondary battery The positive electrode plate obtained above, a polyethylene porous membrane (separator, trade name: Hypore, thickness 20 μm, manufactured by Asahi Kasei Co., Ltd.) and the negative electrode plate obtained above were used. These were immersed in the polymer electrolyte obtained above and impregnated with the polymer electrolyte. Thereafter, a glass plate, a positive electrode plate, a separator, a negative electrode plate, and a glass plate were laminated in this order, and a weight with a pressure of 0.5 gf / cm ² was placed on one glass plate. In this state, it heated at 80 degreeC for 10 minute (s), the positive electrode plate, the separator, and the negative electrode plate were joined, and the electrode group was produced.

  This electrode group was inserted into a laminate outer sheet, the positive electrode lead and the negative electrode lead were led out from the opening of the sheet, and the opening was sealed to produce a battery cell. This battery cell was attached to a battery charge / discharge system (trade name: Multistat 1470E type, manufactured by Toyo Corporation). The battery cell was mounted in the vicinity of the CPU of the battery charge / discharge system. The positive electrode lead and the negative electrode lead were connected to external connection terminals of the battery charge / discharge system. The CPU was previously input with a data table for detecting the capacity of the battery cell, a program for the charge number detecting means, and a data table showing the relationship between the capacity of the battery cell and the reference value for the charge number. Further, the CPU is also used as a heating means, and its maximum temperature reached 70 ° C. Thereby, the solid electrolyte secondary battery of the present invention was produced.

(Example 2)
A solid electrolyte secondary battery of the present invention was produced in the same manner as in Example 1 except that the method for producing the negative electrode was changed as follows.
(Preparation of negative electrode)
A ceramic layer having a thickness of 100 μm was formed by spraying chromium oxide on the surface of an iron roll having a diameter of 50 mm. On the surface of this ceramic layer, a hole which is a circular recess having a diameter of 12 μm and a depth of 8 μm was formed by laser processing, and a convex forming roll was produced. This hole was a close-packed arrangement in which the distance between the axes of adjacent holes was 20 μm. The bottom of the hole has a substantially flat central portion, and the portion where the bottom end and the side surface of the hole are connected has a rounded shape.

  On the other hand, an alloy copper foil (trade name: HCL-02Z, thickness 20 μm, manufactured by Hitachi Cable Ltd.) containing zirconia at a ratio of 0.03% by weight with respect to the total amount at 600 ° C. in an argon gas atmosphere. Heated for 30 minutes and annealed. The alloy copper foil is passed through a pressure contact portion where two convex portion forming rolls are pressure-contacted at a linear pressure of 2 t / cm, both sides of the alloy copper foil are pressure-molded, and the negative electrode current collector used in the present invention Was made. When a cross section in the thickness direction of the obtained negative electrode current collector was observed with a scanning electron microscope, a convex portion was formed on the surface of the negative electrode current collector. The average height of the protrusions was about 8 μm.

  The negative electrode active material layer was formed on a convex portion formed on the surface of the negative electrode current collector using a commercially available vapor deposition apparatus (manufactured by ULVAC, Inc.) having the same structure as the electron beam vapor deposition apparatus 30 shown in FIG. . The conditions for vapor deposition are as follows. Note that the fixed base on which the negative electrode current collector having a size of 35 mm × 185 mm is fixed has a position of an angle α = 60 ° with respect to a straight line in the horizontal direction (the position of the solid line shown in FIG. 7) and an angle (180−α) = 120 °. (The position indicated by the one-dot broken line shown in FIG. 7). Thereby, a columnar negative electrode active material layer in which eight columnar chunks as shown in FIG. 6 were laminated was formed. This negative electrode active material layer grew in the direction in which the convex portion extends from the top of the convex portion and the side surface in the vicinity of the top portion.

Negative electrode active material raw material (evaporation source): silicon, purity 99.9999%, manufactured by High Purity Chemical Laboratory Co., Ltd. Oxygen released from nozzle: purity 99.7%, manufactured by Nippon Oxygen Co., Ltd.
Oxygen release flow rate from nozzle: 80 sccm
Angle α: 60 °
Electron beam acceleration voltage: -8 kV
Emission: 500mA
Deposition time: 3 minutes

The thickness T of the formed negative electrode active material layer was 16 μm. The thickness of the negative electrode active material layer is determined by observing a cross section in the thickness direction of the negative electrode with a scanning electron microscope, and for the ten negative electrode active material layers formed on the surface of the convex portion, the length from the convex portion vertex to the negative electrode active material layer vertex. Each is obtained and obtained as an average value of the ten measured values obtained. Further, when the amount of oxygen contained in the negative electrode active material layer was quantified by a combustion method, it was found that the composition of the compound constituting the negative electrode active material layer was SiO _0.5 .

  Next, lithium metal was deposited on the surface of the negative electrode active material layer. By depositing lithium metal, lithium corresponding to the irreversible capacity stored in the negative electrode active material layer at the time of the first charge / discharge was supplemented. Lithium metal was deposited using a resistance heating vapor deposition apparatus (manufactured by ULVAC, Inc.) in an argon atmosphere. Lithium metal is loaded into a tantalum boat in a resistance heating vapor deposition apparatus, the negative electrode is fixed so that the negative electrode active material layer faces the tantalum boat, and a 50 A current is passed through the tantalum boat in an argon atmosphere. Deposition was performed for 10 minutes.

(Example 3)
A battery cell and a thermostatic chamber (trade name: SU-241, manufactured by ESPEC Corporation) manufactured in the same manner as in Example 1 were mounted on a charge / discharge system (Multistat 1470E type), and the solid electrolyte 2 of the present invention was installed. A secondary battery was produced. The battery cell and the thermostat were mounted so that each was located in the vicinity. The positive electrode lead and the negative electrode lead of the battery cell were connected to external connection terminals of the charge / discharge system. The constant temperature bath is a heating means and is configured to generate heat and heat the battery cells while being controlled by the CPU of the charge / discharge system. The maximum temperature reached in the thermostatic bath was set to 70 ° C. In addition, a data table for detecting the capacity of the battery cell, a program for the charge number detection means, and a data table indicating the relationship between the capacity of the battery cell and the reference value for the number of times of charge were previously input to the CPU of the charge / discharge system.

(Test Example 1)
About the solid electrolyte secondary battery of Examples 1-3, it comprised so that heat control by CPU might not be implemented, and after carrying out constant current charge to 4.2V at 140mA (0.7C) in a 20 degreeC environment, 200mA (1C ) To repeat the constant current discharge to 2.5V. Then, after 100 cycles, constant current charge / discharge was performed in the range of 4.2 V to 2.5 V at 40 mA (0.2 C), and the discharge capacity was examined. The ratio of the 0.2C discharge capacity after 100 cycles to the initial 0.2C discharge capacity was determined as the cycle capacity retention rate (%). The results are shown in Table 1.

(Test Example 2)
In the solid electrolyte secondary batteries of Examples 1 to 3, a test was performed in the same manner as in Test Example 1 except that the battery cell was controlled to be heated at 70 ° C. for 5 minutes every 50 cycles. . The results are shown in Table 1. This means that the reference value for the number of times of charging is 50 times.

(Test Example 3)
In the solid electrolyte secondary batteries of Examples 1 to 3, a test was performed in the same manner as in Test Example 1 except that the battery cells were controlled to be heated at 70 ° C. for 5 minutes every 10 cycles. . The results are shown in Table 1. This means that the reference value for the number of times of charging is 10 times.

(Test Example 4)
In the solid electrolyte secondary batteries of Examples 1 to 3, the battery cells were controlled to be heated at 70 ° C. for 5 minutes every 10 cycles. However, a discharge control means was input in the CPU, and control was performed so that constant current discharge was performed up to 2.5 V at 40 mA before heating. The results are shown in Table 1. This means that the reference value for the number of times of charging is 10 times.

  From Table 1, in the solid electrolyte secondary battery containing the alloy-based negative electrode active material, the battery capacity is remarkably improved by heating the battery cell at a predetermined temperature (here, 70 ° C., 5 minutes) according to the number of times of charging. It is clear. Due to the expansion and contraction of the alloy-based negative electrode active material, the contact state between the negative electrode active material layer and the separator becomes insufficient. On the other hand, in the present invention, fluidity is generated in the polymer electrolyte in the separator by heating the battery cell, so that the entire surface of the negative electrode active material layer and the separator are in uniform contact. As a result, the discharge capacity of the battery is improved.

  The lithium ion secondary battery of the present invention can be used in the same applications as conventional lithium ion secondary batteries, and in particular, personal computers, mobile phones, mobile devices, personal digital assistants (PDAs), portable game devices, and video cameras. It is useful as a power source for portable electronic devices such as In addition, it is expected to be used as a secondary battery for assisting an electric motor, a power tool, a cleaner, a power source for driving a robot, a power source for a plug-in HEV, etc. in a hybrid electric vehicle, a fuel cell vehicle and the like.

It is a block diagram which simplifies and shows the structure of the solid electrolyte secondary battery which is one of the embodiments of the present invention. It is a longitudinal cross-sectional view which simplifies and shows the structure of the principal part (battery cell) of the solid electrolyte secondary battery shown in FIG. It is a block diagram which simplifies and shows the structure of the solid electrolyte secondary battery which is another form of this Embodiment. It is a longitudinal cross-sectional view which shows typically the structure of the negative electrode used by this invention. It is a perspective view which shows typically the structure of the negative electrode electrical power collector contained in the negative electrode shown in FIG. It is a longitudinal cross-sectional view which shows typically the structure of the columnar body contained in the negative electrode active material layer of the negative electrode shown in FIG. It is a side view which shows typically the structure of an electron beam vapor deposition apparatus. It is a side view which shows typically the structure of the vapor deposition apparatus of another form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Solid electrolyte secondary battery 5 Battery cell 6 Heating means 8 Voltage detection means 9 Control means

Claims (13)

  A battery cell including a positive electrode containing a positive electrode active material capable of inserting and extracting lithium, a negative electrode containing an alloy-based negative electrode active material, and a separator impregnated with a solid electrolyte or a solid electrolyte, and a battery cell at the time of discharge at a predetermined temperature or higher A solid electrolyte secondary battery comprising control means for controlling the   The charge number detection means for detecting the number of charge times of the battery cell further includes a control means for controlling the battery cell at the time of discharge to be a predetermined temperature or more according to a detection result by the charge number detection means. Solid electrolyte secondary battery.   The voltage detection means which detects the open circuit voltage of a battery cell further, and a control means controls so that the battery cell at the time of discharge may become more than predetermined temperature according to the detection result by a voltage detection means. Solid electrolyte secondary battery.   2. The discharge time integrating means for integrating the discharge time of the battery cells, and the control means controls the battery cells at the time of discharge to be at a predetermined temperature or higher according to the integration result by the discharge time integrating means. Solid electrolyte secondary battery.   The battery pack further includes a discharge control means for controlling the discharge of the battery cell and a discharge remaining amount detection means for detecting the remaining discharge amount of the battery cell. The discharge control means is controlled so as to discharge the remaining amount of discharge, and further, after charging the battery cell, the battery cell at the time of discharging is controlled to be at a predetermined temperature or higher. Solid electrolyte secondary battery.   The solid electrolyte according to any one of claims 1 to 5, further comprising a heating means for heating the battery cell, wherein the control means controls the heating means so that the battery cell at the time of discharge becomes a predetermined temperature or higher. Secondary battery.   The solid electrolyte secondary battery according to claim 6, wherein the heating means is a resistor that generates heat when energized, or a heat source included in an electric device or an electronic device.   The solid electrolyte secondary battery according to claim 7, wherein the heat source included in the electric device and the electronic device is a central processing unit.   The solid electrolyte secondary battery according to claim 1, wherein the solid electrolyte contains a polymer, and the predetermined temperature is a temperature at which the polymer can be deformed.   The solid electrolyte battery according to claim 9, wherein the predetermined temperature is 60 ° C. or higher.   The solid electrolyte secondary battery according to claim 1, wherein the alloy-based negative electrode active material is an alloy-based negative electrode active material containing silicon or tin.   The solid electrolyte secondary battery according to claim 11, wherein the alloy-based negative electrode active material containing silicon is at least one selected from the group consisting of silicon, silicon oxide, silicon nitride, silicon-containing alloy, and silicon compound.   The solid electrolyte secondary battery according to claim 11, wherein the alloy-based negative electrode active material containing tin is at least one selected from the group consisting of tin, tin oxide, a tin-containing alloy, and a tin compound.

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