JP2001185123A - Whole solid secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection with peripheral apparatus such as a board to be mounted and to reduce area required for mounting, to promote effective mounting of whole solid batteries on small size apparatuses, by devicing terminal take-out shape of the whole solid secondary battery. SOLUTION: In a whole solid secondary battery which comprises positive electrodes, solid electrolyte and negative electrodes layered in order, a hole piercing from one of the electrode side of positive electrode and the negative electrode through the electrolyte and another electrode is provided. The inside wall of the hole is covered with insulation material and conductive material is filled in its center. A take-out terminal of one of the electrodes is provided on another electrode of the above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an all solid state secondary battery.

[0002]

2. Description of the Related Art Conventionally, aqueous or non-aqueous electrolytes have been generally used as electrolytes for various types of batteries. Recently, however, video recording devices, notebook computers, mobile phones and the like have been used. In response to the demand for thinner, lighter, and smaller electronic application devices represented by portable information terminal devices, a gel composed of a polymer material between a pair of positive and negative electrodes instead of the liquid electrolyte as described above. Attention has been focused on a solid electrolyte battery using a liquid electrolyte.

[0003] Various solid electrolyte batteries using an inorganic solid electrolyte or a polymer solid electrolyte as an electrolyte have also been proposed. Since these batteries are solid, they can be thinned by a method such as coating and laminating, and are actively mounted on portable devices.

Further, an all-solid-state secondary battery in which both the electrode active material and the electrolyte are formed of an inorganic compound has been proposed as having high safety and a wide temperature use range.

However, in these all-solid-state rechargeable batteries as well, the terminals for taking out the positive and negative electrodes are formed by using a case as a positive electrode or a negative electrode, a battery connection cap, or the like as a counter electrode, as in the conventional battery. It was necessary to take out the terminal (see, for example, JP-A-7-25188). Alternatively, a polymer battery disclosed in JP-A-6-203826, a laminated lithium secondary battery disclosed in JP-A-7-220754, and a polymer battery disclosed in JP-A-8-1621 are disclosed.
The all-solid-state lithium battery and the like disclosed in Japanese Patent Publication No. 51 need to be taken out with a strip-shaped lead terminal, which is not suitable for a battery for mounting on a small device. That is, in order to connect the terminals, a structure that does not originally contribute to charging and discharging has to be provided outside the battery.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional apparatus, and an object of the present invention is to improve the shape of the terminals of the all-solid-state secondary battery so that the all-solid-state battery can be used for small-sized equipment. In order to efficiently mount the device, it is necessary to improve connectivity with peripheral devices such as a substrate to be mounted and to reduce a required installation area.

[0007]

Means for Solving the Problems In order to achieve the above object, an all solid state secondary battery according to the present invention is directed to an all solid state secondary battery in which a positive electrode, a solid electrolyte, and a negative electrode are sequentially laminated. A hole penetrating the solid electrolyte and the other electrode from one electrode side of the positive electrode or the negative electrode, and covering an inner wall portion of the hole with an insulating material, and filling a central portion with a conductive material. The extraction terminal of the one electrode is provided on the other electrode side.

According to a second aspect of the present invention, in the all solid state secondary battery in which a positive electrode, a solid electrolyte, and a negative electrode are sequentially laminated, one of the positive electrode and the negative electrode is provided. A concave groove is provided on the end surface of the solid electrolyte and the other electrode from the electrode side, and the side wall of the concave groove is coated with an insulating material, and a conductive material is provided outside the groove.
The extraction terminal of the one electrode is provided on the other electrode side.

[0009]

With the above configuration, in a flat plate-shaped all solid state secondary battery, both terminals of the positive electrode and the negative electrode of the battery can be arranged in alignment with one of the electrodes. As a result, in the conventional secondary battery, there is no need for a mechanism for connecting the battery, holding by the case, or laying out the connection lead wires around the battery terminals, which were necessary at the time of mounting. As a result, the efficiency of mounting a secondary battery in a small device such as a mobile phone can be dramatically increased.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows the structure of the battery element of the all-solid-state secondary battery according to the first embodiment of the present invention, and FIG. FIG. 3 is a diagram showing a configuration of a battery element of the all-solid-state secondary battery according to the second aspect of the invention. FIG. 4 is a diagram showing the electrode terminals in a partially enlarged manner.

The all-solid-state secondary battery has a structure in which a solid electrolyte 2 is sandwiched between a positive electrode 1 and a negative electrode 3.

A hole 4 penetrating in a direction perpendicular to the surfaces of the electrodes 1 and 3, that is, in a direction perpendicular to the electrodes 1 and 3 opposed to each other.

The inner wall of the hole 4 is insulated by an insulating material 5, and the center is filled with a conductive material 6. The conductive material 6 is connected to current collectors 7 and 8 formed on one of the positive electrode 1 and the negative electrode 3. In this figure, it is connected to the negative electrode current collector 7 and is taken out to the positive electrode current collector 8 side facing the connected negative electrode 3.
A positive electrode terminal 9 is formed on the positive electrode current collector 8. Further, a negative electrode terminal 10 made of a conductive material connected to the negative electrode current collector 7 is also formed in the positive electrode current collector 8, and both terminals are taken out only on the surface on the positive electrode 1 side of the battery. It has a shape.

A positive electrode 1, a negative electrode 3, and a solid electrolyte 2
Are composed of the following materials. That is,
The active material of the electrode material is a transition metal chalcogenide
And transition metal oxides having a spinel structure. Cal
TiO as a cogenide_Two, Cr_ThreeO₈, V_TwoO_Five, Mn
O_Two, CoO_TwoOxides such as TiS_Two, VS_Two, FeS
Such as sulfides, and the spinel structure
LiMn_TwoO_FourTransition metal oxides represented by
Is a partially element-substituted oxide or Li_FourMn_FiveO ₁₂Such as
Using various transition metal oxides and their partial substitutional oxides
Can be In sulfide systems, the active material
Oxide-based active material is highly reactive
desirable.

When these materials are used as a positive electrode active material and a negative electrode active material, their selection is not particularly limited, and the charge and discharge potentials of two types of transition metal oxides or sulfides are compared. A battery having an arbitrary potential can be formed by using a material having a higher potential as a positive electrode and a material having a lower potential as a negative electrode. Further, for the purpose of assisting electron conductivity in the electrodes 1 and 3, S
A conductive additive such as nO ₂ or TiO ₂ , ITO or carbon may be added.

The inorganic solid electrolyte 2 used in the present invention includes, for example, Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ and Li _3.6
Crystalline solid electrolyte such as Ge _0.6 V _0.4 O _4, 30LiI
-41Li ₂ O-29P ₂ O ₅ and 40Li ₂ O-30LiI
One _{35B 2 O 3 -25LiNbO 3, 10Li} 2 O-25B
₂ O ₃ -15SiO ₂ oxide-based amorphous solid electrolytes such as _{-50ZnO, 45LiI-37Li 2 S-} 18P 2 S 5 and Li ₃ PO ₄ -63Li ₂ sulfide such as S-36SiS ₂ amorphous solid Although an electrolyte or the like can be used, it is preferable to use an oxide-based material in order to maintain cycle charge / discharge performance from the viewpoint of stability of the active material.

The shape of the hole or groove 4 is not particularly limited, but is directly related to the amount of electrode material that is an active material that contributes to charging and discharging of the battery, from the viewpoint of the energy density of the battery. The amount should not cause any problem as long as the current value can be secured.

As the insulating material 5 for filling the hole 4, any material can be used as long as the insulating material such as an insulating resin, an inorganic oxide, or a glass amorphous material can secure the insulating property and can fill the hole or the groove 4. May be used.

As the conductive material 6, a metal material is mainly suitable, but a semiconductor material such as an oxide can be used as long as the electronic conductivity can be ensured. However, considering the connection with the electrode current collectors 7 and 8, it is desirable to use the same material as the current collector material. That is, as a material constituting the current collectors 7 and 8, any one or two or more metals selected from Au, Ag, Pd, Pt, Ni, Al, Cu, or Ti or an alloy thereof is used as a main component. Metal material or a conductive paste thereof is used.

The method for depositing the current collectors 7 and 8 on the electrodes 1 and 3 is not particularly limited, but can be formed by a method such as vacuum deposition, screen printing, sputtering, CVD or plating.

The battery element 9 is covered or packed with the insulating resin coating 12 shown in FIG. 1 to form an all-solid secondary battery 13. As the material of this exterior,
It is externally covered with a polymer resin coating such as polyethylene, polypropylene, polyester and polyimide.

Next, a method for manufacturing the battery element 9 will be described.
The battery element 9 is formed by laminating the above-described materials. The laminated structure can be formed by forming each electrode layer and the solid electrolyte layer into a sheet or performing screen printing on the substrate, followed by drying and removing the substrate. The formed laminate is pressurized and heated by a hot press method, fired, and densified to form the battery element 9. In the case of the former sheet forming, first apply each electrode and paste of solid electrolyte to the required thickness by screen printing or doctor blade method,
The obtained sheet is dried, the solid electrolyte is sandwiched between positive and negative electrodes, dried, degreased, and fired by a hot press method. In addition, the battery element 9 can be formed by screen printing or a sputtering method in an inert atmosphere for all of the positive and negative electrodes 1, 3 and the solid electrolyte 2.

The holes or grooves 4 are formed as follows. That is, as a method of performing processing before firing, sheet forming or laminating is applied, followed by forming by punching, or laminating while forming an uncoated portion using masking or the like during printing. In addition, as a method of performing processing after hot pressing, it can be formed by processing using any of dicing, laser abrasion, chemical etching, plasma etching, ion etching, and electron beam.

The two-layer structure of the insulating material 5 and the conductive material 6 covering the inner wall of the hole or groove 4 is formed as follows. A fibrous sealing material in which a conductive material 6 is previously enclosed is used as the insulating material 6, and the fibrous sealing material is processed into a hole or groove 4 for use. In addition, any method, such as a method of forming by printing or a method of forming by heating and curing with a resin, may be used as long as it can be joined without deteriorating battery performance. After joining in this manner, the electrode is cut in accordance with the thickness of the electrodes 1 and 3 to form a penetrating terminal portion, and then joined to the current collector 7 or the current collector 8. At this time, the terminal penetrating the current collector 7 or the current collector 8 is connected to one electrode side,
When the opposite electrode-side current collector 7 or current collector 8 is formed, the terminal portion is masked to avoid a short circuit.

Using the battery element of the all-solid-state secondary battery, the place where the electrode terminal is to be finally formed (the hole position is fixed, in this case the negative electrode terminal) is masked, and the resin coating exterior is hardened by dipping or the like. Later, the masking is peeled off, and the portion that appears on the surface forms the positive and negative electrode terminals 10 of the battery to form an all-solid secondary battery.

[0026]

EXAMPLES (Example 1) Each battery element was formed as follows. As the positive electrode active material Li [Li _{0 .1} Mn
_1.9 ] O ₄ was used. Li as a starting material with respect to MnO ₂
A compound such as ₂ CO _{3 is} converted to a predetermined molar ratio of Li: Mn 1.1:
1.9 and mixed at 450 ° C. to 750 in air.
It was synthesized by firing at ℃. For this active material 75 wt%, 30LiI-41Li ₂ as inorganic solid electrolytes
O-29P ₂ O ₅ powder 15 wt%, IT as conductive additive
O (In ₂ O ₃ : SnO ₂ = 95: 5) was weighed at 10% by weight and mixed well. To this mixed powder, a commercially available binder (polyvinyl butyral) was added in an amount of 5% by weight as a molding binder, and a paste was prepared using a ball mill with toluene as a solvent. After the prepared paste was molded to a thickness of 100 μm to evaporate the solvent, the binder was degreased at 350 ° C. and fired in the air at 650 ° C. to produce an electrode.

On the other hand, as the negative electrode active material, Li [Li _1/3
[Mn _5/3 ] O ₄ was used. As a starting material, a compound such as Li ₂ Co ₃ is mixed with TiO _{2 so} that a predetermined molar ratio of Li: Ti is 4: 5, and 650 to 950 in the air is mixed.
It was synthesized by firing at ℃. Like the positive electrode using the negative electrode active material, an inorganic solid electrolyte _{30LiI-41Li 2 O-29P 2} O 5 powder with respect to the active material of 85 wt% 1
The powder was mixed at a ratio of 5% by weight to prepare a negative electrode mixed powder.
To this negative electrode mixed powder, a binder was added as a molding binder in an amount of 5% by weight in the same manner as the positive electrode, and a paste was prepared using a ball mill with toluene as a solvent.
The prepared paste was formed into a thickness of 80 μm, and after the solvent was volatilized, the binder was degreased and fired in the same manner as the positive electrode to prepare an electrode.

The solid electrolyte 10Li ₂ O-25B ₂ O
₃ -15SiO the ₂ -50ZnO were mixed in a weight ratio of 80:20 with respect to the solid electrolyte, and the binder was added 5 parts by weight of toluene as with the electrodes to prepare a paste using a solvent. The prepared paste was applied on the baked positive electrode by screen printing with a thickness of 20 μm. After the application, the solvent is dried and evaporated to degrease the binder at 350 ° C. in the air, and then the fired negative electrodes are overlapped to integrate the three layers, and then hot-pressed at a pressure of 25 to 59 MPa at a pressure of 25 to 59 MPa. It baked under pressure at ~ 700 ° C. The battery element was formed into a size of 30 mm × 30 mm by this method.

Drilling was performed on the battery element using a carbon dioxide laser. By irradiating the pulse laser, a through hole having a diameter of 2.0 mm was formed in the center of the battery element.

A glass fiber in which a 1.0 mmφ Au wire is sealed is inserted into a pre-processed sealing glass into the hole portion, and heated and bonded at 350 ° C. in the atmosphere. The portions protruding from the respective electrode surfaces were cut. Thereafter, on the negative electrode side, an Au current collector was vacuum-deposited on the entire surface. On the other hand, on the positive electrode side, after masking the portions 5 and 6 filled in the holes, an Au current collector was also deposited on the entire surface. The deposition was performed at 2500 ° C. to form a unit cell. After the vapor deposition, the portion corresponding to the positive electrode terminal was masked again, and the entire unit cell was coated with resin by dipping into a resin, and cured by heating. Thereafter, the masking was removed to complete the all-solid secondary battery.

The fabricated battery was connected face down on a printed circuit board by soldering. The area occupied by the battery on the printed circuit board required for connection is 30.2 mm x 30.2 mm
(Height: 0.6 mm).

The charge / discharge characteristics of the battery were evaluated using a secondary battery charge / discharge device. As a charging condition, the all solid state battery was charged to 3.5 V with a current of 50 μA, and after the voltage reached 3.5 V, charging was stopped and held for 5 minutes, and then a discharge current of 50 μA to a voltage of 1.0 V was applied. A charge / discharge cycle test was performed by repeating discharge, stopping the discharge, holding for 5 minutes, and charging again to 3.5V. The charge and discharge were performed at 80 ° C. for the acceleration test. The battery performance was evaluated for five cells based on the transition of the discharge capacity for each cycle. (Comparative Example 1) Except that no hole was formed,
A battery element of 0 mm × 30 mm was produced.

Au was vapor-deposited similarly as a current collector of the battery, and then Al lead (4 mm × 8 mm × 0.05 mmt) was obtained.
The two were bonded by heating and curing each of the positive and negative electrodes using a conductive adhesive. Thereafter, a coating battery was formed with a resin in the same manner as in Example 1 to obtain a comparative battery.

The manufactured battery was subjected to ultrasonic welding on a printed circuit board in the same manner as in Example 1. The area occupied by the battery on the printed circuit board required for connection is 30.2 mm x 34.2 m
m (height 0.7 mm). 80 as in the first embodiment.
The cycle characteristics were evaluated by a secondary battery charging / discharging device at ℃. Table 1 shows the test results of the cycle characteristics.

[0035]

[Table 1]

In the comparative example, it was confirmed that the mounting area required was slightly more than 10% of the mounting area of the embodiment, and that the size of the mounting can be reduced by introducing the terminal extracting shape according to the present invention.

Although the terminal shown in the comparative example can be attached by bending it, the method shown in the example can take out the terminal to an arbitrary position on the surface of the electrode, so that the example is particularly effective. it is obvious.

In addition, it was confirmed that the same cycle capacity characteristics were obtained in the examples and the comparative examples up to the initial 25 cycles. However, after 150 cycles of charging and discharging,
In the comparative example, the capacity deterioration rapidly progressed.
No such degradation occurred.

This is presumably because the use of a conductive adhesive (organic binder) for connection of the terminal portions accelerated the deterioration of conductivity due to a long-term heating test.

Accordingly, it was confirmed that the battery structure having the structure shown in the embodiment can be reduced in installation area and is a connection method having higher reliability than other connection methods.

In the present invention, Li [Li _0.1 Mn _1.9 ] O ₄ and Li [Li _1/3 Mn having a spinel structure are used.
_5/3 ] 10 L as solid electrolyte using O ₄ as active material
_{i 2 O-25B 2 O 3} -15SiO 2 was used like -50ZnO, so long as not departing from the gist of the invention the active material and the solid electrolyte can be variously modified.

It is apparent that various positions can be taken for the processing position and the like in accordance with the mounting device. Also,
Drilling is not limited to laser processing, and various modifications can be made without departing from the spirit of the invention.

[0043]

As described above, claims 1 and 2 are as described above.
According to the invention according to the invention, a hole or a concave groove is formed from one electrode side to the other electrode side, and an extraction terminal of one electrode is provided on the other electrode side through this hole or concave groove portion. Accordingly, an all-solid secondary battery capable of reducing the mounting area and volume of the battery and enabling highly reliable connection can be formed.

When the invention according to claims 1 and 2 is applied to a wound type lithium ion battery or a gel electrolyte battery, the processing positioning, sealing of the electrolyte solution, etc. It is obvious that processing is extremely difficult, and the present invention is limited to a stacked type all solid state battery. Therefore, this is an effective technique for further improving the mountability to equipment using an all-solid secondary battery, and can contribute to miniaturization and improvement of reliability of equipment.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a battery element of an all-solid secondary battery.

FIG. 2 is a structural sectional view of an all solid state secondary battery.

FIG. 3 is a diagram showing a structure on a negative electrode terminal side.

FIG. 4 is a diagram showing a structure on a positive electrode terminal side.

[Explanation of symbols]

1: positive electrode, 2: solid electrolyte, 3: negative electrode, 4: hole (groove), 5: insulating material, 6: conductive material, 7: negative electrode current collector, 8: positive electrode current collector, 9: Battery element, 10: negative electrode terminal, 11: positive electrode terminal, 12: coating exterior, 1
3: All-solid-state secondary battery

Continuing on the front page (72) Inventor Shinji Magome 3-5-5 Koudai, Seikacho, Soraku-gun, Kyoto Kyoto Inside the Central Research Laboratory of Cera Corporation (72) Inventor Makoto Osaki 3-5-kokoda Seikacho, Soraku-gun, Kyoto Kyoto Central Research Laboratory, Sera Corporation (72) Inventor Tohru Hara 3-5 Koikodai, Seikacho, Soraku-gun, Kyoto Prefecture Kyoto Central Research Laboratory (72) Inventor Ei Higuchi 3-chome Koikadai, Soraku-gun, Kyoto Prefecture Address Kyocera Corporation Central Research Laboratory F term (reference) 5H022 AA09 CC02 CC03 CC08 CC12 KK03 5H029 AJ14 AK02 AK03 AK05 AL02 AL03 AL04 AM11 BJ04 BJ12 DJ05 DJ14

Claims (2)

[Claims] 1. An all-solid secondary battery in which a positive electrode, a solid electrolyte, and a negative electrode are sequentially laminated, wherein one of the positive electrode and the negative electrode passes through the solid electrolyte and the other electrode. A hole is provided, and the inner wall of the hole is covered with an insulating material, and the center is filled with a conductive material.
An all-solid secondary battery, wherein an extraction terminal for the one electrode is provided on the other electrode side. 2. In an all-solid secondary battery in which a positive electrode, a solid electrolyte, and a negative electrode are sequentially laminated, an end face of the solid electrolyte and the other electrode from one of the positive electrode and the negative electrode. A concave groove is provided in the portion, a side wall portion of the concave groove is covered with an insulating material, and a conductive material is disposed outside the concave groove, and a takeout terminal of the one electrode is provided on the other electrode side. All-solid rechargeable battery.