JP2017195076A - Bipolar type battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a short circuit in a bipolar type battery.SOLUTION: A bipolar type battery comprises: a bipolar electrode having a piece of bipolar current collector foil, a positive electrode mixture layer and a negative electrode mixture layer; and a unit cell having a positive electrode having a piece of positive electrode current collector foil and a positive electrode mixture layer, and a negative electrode having a piece of negative electrode current collector foil and a negative electrode mixture layer. The positive electrode has a positive electrode lamination part and a positive electrode terminal part. The negative electrode has a negative electrode lamination part and a negative electrode terminal part. In a laminating direction of the bipolar type battery, a first solid electrolyte layer is disposed between the bipolar electrode and the positive electrode. In the laminating direction of the bipolar type battery, a second solid electrolyte layer is disposed between the bipolar electrode and the negative electrode. In an in-plane direction of the bipolar type battery, the first solid electrolyte layer and the second solid electrolyte layer are larger than the positive electrode and the negative electrode.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a bipolar battery.

  In recent years, secondary batteries have been used for large electric devices (for example, power sources for vehicles such as HEVs (hybrid vehicles) and EVs (electric vehicles) and power storage power sources), mobile phones, smartphones, portable game machines, and the like. It tends to expand. Secondary batteries include nickel metal hydride batteries, nickel cadmium batteries, lead batteries, lithium ion batteries, sodium ion batteries, etc., and their electromotive force is about 1.5 V to 3 V or more depending on the potential of the material used. . In many of these secondary batteries, an electrolytic solution is used. However, in recent years, development of solid electrolytes that are in a solid state at room temperature and have ionic conductivity has been accelerating. Since the solid electrolyte itself can have ionic conductivity while ensuring the insulation between the positive and negative electrodes, the functions of the separator and the non-aqueous electrolyte used in the conventional non-aqueous secondary battery are combined into one. It is possible to achieve compatibility with members.

  A secondary battery using a solid electrolyte has an advantage that it is excellent in safety as compared with that using a nonaqueous electrolytic solution containing an organic solvent or the like. Moreover, since the solid electrolyte can separate adjacent solid electrolytes arranged between the electrodes, it is possible to take a series structure (bipolar structure) in the battery, which is several times the series electromotive force of the material. The electromotive force can be obtained in one cell.

  In relation to the above, for example, Patent Document 1 discloses a unit cell of a lithium battery in which a positive electrode layer is formed on one surface of a solid electrolyte and a negative electrode layer is formed on the other surface; A plurality of bipolar type laminated batteries including internal electrode layers alternately laminated, the plurality of laminated batteries are stacked via a positive current collector foil and a negative current collector foil, and are electrically connected in parallel, Furthermore, an all-solid battery characterized by being sealed with a mold resin is disclosed.

JP 2014-116156

  In the structure described in Patent Document 1, since there are portions having the same size of the laminate in the in-plane direction of the bipolar all solid lithium battery, the bipolar laminated sintered body, the positive electrode current collector foil, and the negative electrode current collector foil The components of the laminate may come into contact with each other and cause a short circuit due to vibration when the resin is sealed with a resin mold or when a moving body equipped with an all-solid battery is moved.

  An object of the present invention is to prevent a short circuit of a bipolar battery.

  The features of the present invention for solving the above problems are as follows, for example.

  Bipolar electrode having bipolar current collector foil, positive electrode composite material layer, negative electrode composite material layer, positive electrode having positive electrode current collector foil and positive electrode composite material layer, unit cell having negative electrode having negative electrode current collector foil and negative electrode composite material layer A positive electrode has a positive electrode stacking portion and a positive electrode terminal portion, a negative electrode has a negative electrode stacking portion and a negative electrode terminal portion, and in the stacking direction of the bipolar battery, the bipolar electrode and The first solid electrolyte layer is disposed between the positive electrodes, and the second solid electrolyte layer is disposed between the bipolar electrode and the negative electrode in the stacking direction of the bipolar battery, and the first solid electrolyte layer is disposed in the in-plane direction of the bipolar battery. The solid electrolyte layer and the second solid electrolyte layer are bipolar batteries larger than the positive electrode and the negative electrode.

  According to the present invention, a short circuit of a bipolar battery can be prevented. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a plane schematic diagram which shows an example of the lithium ion secondary battery which concerns on one Embodiment of this invention. It is a plane schematic diagram which shows an example of the lithium ion secondary battery which concerns on one Embodiment of this invention. It is a plane schematic diagram which shows an example of the lithium ion secondary battery which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional structural view of the A-A ′ plane of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various modifications by those skilled in the art are within the scope of the technical idea disclosed in this specification. Changes and modifications are possible. In all the drawings for explaining the present invention, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

  In the present invention, embodiments of the structure of a lithium ion secondary battery will be mainly described. However, the present invention is not limited to a lithium ion secondary battery, but a nickel hydrogen battery, a nickel cadmium battery, a lead battery, a lithium ion battery, a sodium ion battery, or the like. Any secondary battery or primary battery can be used as long as it uses a solid electrolyte.

  1, 2, and 3 are schematic plan views illustrating an example of a bipolar battery according to an embodiment of the present invention. FIG. 2 is a view in which the negative electrode 201 and the second solid electrolyte layer 302 are removed from FIG. FIG. 3 is a view in which the positive electrode 101 and the first solid electrolyte layer 301 are removed from FIG.

  The bipolar battery 10 includes a positive electrode 101, a negative electrode 201, a first solid electrolyte layer 301, a second solid electrolyte layer 302, a third solid electrolyte layer 303, and a bipolar electrode 401. In FIG. 2, the positive electrode 101 has a positive electrode laminate portion 102 and a positive electrode terminal portion 103. In FIG. 3, the negative electrode 201 has a negative electrode laminate portion 202 and a negative electrode terminal portion 203. The first solid electrolyte layer 301 and the second solid electrolyte layer 302 have substantially the same size, and are arranged with mirror images reversed in the stacking direction of the bipolar battery 10.

  In FIG. 1, in the in-plane direction of the bipolar battery 10, the negative electrode stacking portion 202 is made larger than the positive electrode stacking portion 102, but may be the same or smaller. By enlarging the negative electrode laminate 202 relative to the positive electrode laminate 102, lithium deposition from lithium contained in the positive electrode active material in the positive electrode 101 can be suppressed. In FIG. 1, the positions of the first solid electrolyte layer 301 and the second solid electrolyte layer 302 are shifted in the in-plane direction of the bipolar battery 10, but this is for explanation, In terms of manufacturing design, the positions of the first solid electrolyte layer 301 and the second solid electrolyte layer 302 may be overlapped without shifting.

  FIG. 4 is a cross-sectional structure diagram of the A-A ′ plane of FIG. 1, and is a schematic plan view illustrating an example of a bipolar battery according to an embodiment of the present invention. The stacking direction and in-plane direction of the bipolar battery 10 are defined as shown in FIG. For illustration, the positive electrode 101, the negative electrode 201, the first solid electrolyte layer 301, the second solid electrolyte layer 302, the third solid electrolyte layer 303, and the bipolar electrode 401 are illustrated as being spatially separated. In an actual battery, there is almost no space between them, and they are in contact in a plane. A bipolar battery 10 according to an embodiment of the present invention includes a positive electrode 101, a negative electrode 201, a bipolar electrode 401, a first solid electrolyte layer 301, a second solid electrolyte layer 302, a third solid electrolyte layer 303, and an auxiliary wire. 600. In FIG. 4, in the stacking direction of the bipolar battery 10, the negative electrode 201, the third solid electrolyte layer 303, the positive electrode 101, the third solid electrolyte layer 303, the negative electrode 201, the third solid electrolyte layer 303, the positive electrode 101, the first 1 solid electrolyte layer 301, bipolar electrode 401, second solid electrolyte layer 302, negative electrode 201, third solid electrolyte layer 303, positive electrode 101, third solid electrolyte layer 303, negative electrode 201, third solid electrolyte layer 303 and the positive electrode 101 are stacked in this order.

  The unit cell 20 is composed of the positive electrode 101, the negative electrode 201, and the third solid electrolyte layer 303. The positive electrode 101 includes a positive electrode current collector foil 104 and a positive electrode mixture layer 105. A positive electrode mixture layer 105 is formed on both surfaces of the positive electrode current collector foil 104. The negative electrode 201 includes a negative electrode current collector foil 204 and a negative electrode mixture layer 205. A negative electrode mixture layer 205 is formed on both surfaces of the negative electrode current collector foil 204. In FIG. 4, the lowermost negative electrode 201 has the negative electrode mixture layer 205 formed only on one surface of the negative electrode current collector foil 204 (the surface on which the third solid electrolyte layer 303 is disposed). In the uppermost positive electrode 101, the positive electrode mixture layer 105 is formed only on one surface of the positive electrode current collector foil 104 (the surface on which the third solid electrolyte layer 303 is disposed).

  The bipolar electrode 401 includes a bipolar current collector foil 404, a positive electrode mixture layer 105, and a negative electrode mixture layer 205. The positive electrode mixture layer 105 is formed on one surface of the bipolar current collector foil 404, and the negative electrode mixture layer 205 is formed on the other surface of the bipolar current collector foil 404.

  The plurality of unit cells 20 are connected by bipolar electrodes 401. Specifically, a positive electrode 101 in one unit cell 20 and a negative electrode 201 of another unit cell 20 stacked adjacent to the unit cell 20 are connected by a bipolar electrode 401. In the stacking direction of the bipolar battery 10, a first solid electrolyte layer 301 and a second solid electrolyte layer 302 are disposed between the unit cell 20 and the bipolar electrode 401.

<Positive electrode current collector foil 104>
As the positive electrode current collector foil 104, an aluminum foil, an aluminum perforated foil having a pore diameter of 0.1 to 10 mm, an expanded metal, a foamed aluminum plate, or the like is used. As the material, stainless steel, titanium, or the like can be applied in addition to aluminum. The thickness of the positive electrode current collector foil 104 is preferably 10 nm to 1 mm. About 1-100 micrometers is desirable from a viewpoint of the energy density of a secondary battery and the mechanical strength of an electrode.

<Positive electrode mixture layer 105>
The positive electrode mixture layer 105 contains at least a positive electrode active material capable of inserting and extracting Li. Examples of the positive electrode active material include LiCo-based oxides, LiNi-based composite oxides, LiMn-based composite oxides, Li-Co-Ni-Mn composite oxides, LiFeP-based oxides, and the like. In the positive electrode mixture layer 105, a conductive material responsible for electronic conductivity in the positive electrode mixture layer 105, a binder that secures adhesion between the materials in the positive electrode mixture layer 105, and further in the positive electrode mixture layer 105 A solid electrolyte for ensuring ionic conductivity may be included.

  As a method for producing the positive electrode mixture layer 105, a material contained in the positive electrode mixture layer 105 is dissolved in a solvent to form a slurry, which is applied onto the positive electrode current collector foil 104. The coating method is not particularly limited, and for example, a conventional method such as a doctor blade method, a dipping method, or a spray method can be used. Further, a plurality of positive electrode mixture layers 105 may be laminated on the positive electrode current collector foil 104 by performing a plurality of times from application to drying. Thereafter, the positive electrode mixture layer 105 is formed through a drying process for removing the solvent and a pressing step for ensuring electron conductivity and ion conductivity in the positive electrode mixture layer 105.

  The thickness of the positive electrode mixture layer 105 is designed according to the energy density, rate characteristics, and input / output characteristics of the all-solid-state battery, but generally has a size of several μm to several hundred μm. The particle size of a material such as a positive electrode active material included in the positive electrode mixture layer 105 is defined to be equal to or less than the thickness of the positive electrode mixture layer 105. When the positive electrode active material powder includes coarse particles having a particle size equal to or larger than the thickness of the positive electrode mixture layer 105, the coarse particles are previously removed by sieving classification, wind classification, etc. Prepare the particles.

<Negative electrode current collector foil 204>
For the negative electrode current collector foil 204, a copper foil, a copper perforated foil having a pore diameter of 0.1 to 10 mm, an expanded metal, a foamed copper plate, or the like is used. The thickness of the negative electrode current collector foil 204 is preferably 10 nm to 1 mm. About 1-100 micrometers is desirable from a viewpoint of the energy density of an all-solid-state battery and the mechanical strength of an electrode.

<Negative electrode mixture layer 205>
The negative electrode mixture layer 205 contains at least a positive electrode active material capable of inserting and extracting Li. Examples of the negative electrode active material include carbon-based materials such as natural graphite, soft carbon, and amorphous carbon, Si metal, Si alloy, lithium titanate, and lithium metal. In the negative electrode mixture layer 205, a conductive material responsible for electronic conductivity in the negative electrode mixture layer 205, a binder that ensures adhesion between the materials in the negative electrode mixture layer 205, and further in the negative electrode mixture layer 205 A solid electrolyte for ensuring ionic conductivity may be included.

  The thickness of the negative electrode mixture layer 205 is designed in accordance with the energy density, rate characteristics, and input / output characteristics of the all-solid-state battery, but generally has a size of several μm to several hundred μm. The particle size of the material such as the positive electrode active material included in the negative electrode mixture layer 205 is defined to be equal to or less than the thickness of the negative electrode mixture layer 205. When the positive electrode active material powder has coarse particles having a particle size equal to or larger than the thickness of the negative electrode mixture layer 205, the coarse particles are previously removed by sieving classification, wind classification, etc. Prepare the particles.

<Bipolar current collector foil 404>
For the bipolar current collector foil 404, in addition to the positive electrode current collector foil 104 and the negative electrode current collector foil 204 described above, a bipolar current collector foil in which a positive electrode current collector foil and a negative electrode current collector foil are laminated is used. The thickness of the bipolar current collector foil 404 is preferably 10 nm to 1 mm. About 1-100 micrometers is desirable from a viewpoint of the energy density of a secondary battery and the mechanical strength of an electrode.

<Solid electrolyte layer>
The first solid electrolyte layer 301, the second solid electrolyte layer 302, and the third solid electrolyte layer 303 contain a solid electrolyte. Examples of solid electrolytes include organic compounds such as sulfide systems such as Li ₁₀ Ge ₂ PS ₁₂ and Li ₂ S—P ₂ S ₅ , oxide systems such as Li—La—Zr—O, ionic liquids and room temperature molten salts. Examples thereof include materials that do not exhibit fluidity within the operating temperature range of a secondary battery, such as polymer types supported on inorganic particles, semi-solid electrolytes, and the like. The solid electrolyte layer is formed by compressing powder, mixing with a binder, applying the slurryed solid electrolyte layer to a release material, or impregnating a carrier. The thickness of the solid electrolyte layer is a size of several nm to several mm from the viewpoint of ensuring the energy density of the secondary battery, ensuring electronic insulation, and the like.

<Auxiliary line 600>
The positive electrode 101 and the negative electrode 201 included in the unit cell 20 are electrically connected as indicated by an auxiliary line 600 indicating electrical connection. Specifically, the positive electrode terminal portion 103 in FIG. 2 is the positive electrode current collector foil 104 in FIG. 4, and the negative electrode terminal portion 203 in FIG. 3 is the negative electrode current collector foil 204 in FIG. The current collector foils 204 are electrically connected using terminal portions. Accordingly, the unit cells 20 are electrically connected in parallel. Further, since the plurality of unit cells 20 are connected by the bipolar electrode 401, the plurality of unit cells 20 are electrically connected in series.

  The positive electrode current collector foil 104, the positive electrode material mixture layer 105, the negative electrode current collector foil 204, the negative electrode material mixture layer 205, the first solid electrolyte layer 301, the second solid electrolyte layer 302, and the third solid electrolyte layer 303 are The size is defined so as to follow the auxiliary line 800 indicating the positional relationship of each material in the stacking direction.

  As shown in FIG. 4, the third solid electrolyte layer 303 is larger than the positive electrode mixture layer 105 and the negative electrode mixture layer 205 in the in-plane direction of the bipolar battery 10, and the positive electrode is in the region of the third solid electrolyte layer 303. A composite material layer 105 and a negative electrode composite material layer 205 are disposed. As shown in FIG. 2, the third solid electrolyte layer 303 is larger than the positive electrode stack portion 102 in the in-plane direction of the bipolar battery 10, and the positive electrode stack portion 102 is disposed in the region of the third solid electrolyte layer 303. Yes. As shown in FIG. 3, the third solid electrolyte layer 303 is larger than the negative electrode stack portion 202 in the in-plane direction of the bipolar battery 10, and the negative electrode stack portion 202 is disposed in the region of the third solid electrolyte layer 303. Yes. As shown in FIG. 4, the third solid electrolyte layer 303 is not in physical contact with the auxiliary line 600. Thereby, the positive electrode 101 and the negative electrode 201 can be electrically insulated in the unit cell 20, and the short circuit of the bipolar battery by vibration can be prevented. Moreover, since the short circuit of the bipolar battery can be prevented without using the mold resin, the productivity of the bipolar battery can be improved.

  As shown in FIG. 2, the first solid electrolyte layer 301 is larger than the positive electrode 101 in the in-plane direction of the bipolar battery 10, and the positive electrode 101 is disposed in the region of the first solid electrolyte layer 301. As shown in FIG. 3, the second solid electrolyte layer 302 is larger than the negative electrode 201 in the in-plane direction of the bipolar battery 10, and the negative electrode 201 is disposed in the region of the second solid electrolyte layer 302. Thereby, the positive electrode 101 or the negative electrode 201 and the bipolar electrode 401 can be electrically insulated, and a short circuit of the bipolar battery due to vibration can be prevented. Moreover, since the short circuit of the bipolar battery can be prevented without using the mold resin, the productivity of the bipolar battery can be improved.

  As shown in FIGS. 1 to 4, the bipolar electrode 401 is larger than the first solid electrolyte layer 301, the second solid electrolyte layer 302, and the third solid electrolyte layer 303 in the in-plane direction of the bipolar battery 10, In the region of the bipolar electrode 401, a first solid electrolyte layer 301, a second solid electrolyte layer 302, and a third solid electrolyte layer 303 are arranged. Thereby, the connection between the positive electrode 101 of a certain unit cell 20 and the negative electrode 201 of another unit cell 20 adjacent to the certain unit cell 20, and the first solid electrolyte layer 301 and the second solid electrolyte layer 302 are electrically connected. Insulation is possible, and short-circuiting of the bipolar battery due to vibration can be prevented. Moreover, since the short circuit of the bipolar battery can be prevented without using the mold resin, the productivity of the bipolar battery can be improved.

  In the above, the degree of difference in the size of each constituent member is based on the electron / ion insulation, the energy density of the bipolar battery 10, the manufacturing tolerance at the time of manufacturing, the dimensional tolerance at the time of stacking the constituent members, etc. It is determined in view of the size of the positive electrode stacking portion 102 and the negative electrode stacking portion 202. Specifically, the size is preferably several tens of μm to several cm, more preferably several mm.

DESCRIPTION OF SYMBOLS 10 ... Bipolar type battery 20 ... Unit cell 101 ... Positive electrode 102 ... Positive electrode laminated part 103 ... Positive electrode terminal part 104 ... Positive electrode collector foil 105 ... Positive electrode compound material layer 201 ... Negative electrode 202 ... Negative electrode laminated part 203 ... Negative electrode terminal part 204 ... Negative electrode Current collecting foil 205 ... Negative electrode composite material layer 301 ... First solid electrolyte layer 302 ... Second solid electrolyte layer 303 ... Third solid electrolyte layer 401 ... Bipolar electrode 404 ... Bipolar current collecting foil 600 ... Electric connection Auxiliary line 800 ... Auxiliary line indicating the positional relationship of each material in the stacking direction

Claims (5)

A bipolar current collector foil, a positive electrode mixture layer, a bipolar electrode having a negative electrode mixture layer, and
A unit cell having a positive electrode having a positive electrode current collector foil and a positive electrode mixture layer, a negative electrode having a negative electrode current collector foil and a negative electrode mixture layer, and a bipolar battery comprising:
The positive electrode has a positive electrode laminate portion and a positive electrode terminal portion,
The negative electrode has a negative electrode laminate portion and a negative electrode terminal portion,
In the stacking direction of the bipolar battery, a first solid electrolyte layer is disposed between the bipolar electrode and the positive electrode,
In the stacking direction of the bipolar battery, a second solid electrolyte layer is disposed between the bipolar electrode and the negative electrode,
In the in-plane direction of the bipolar battery, the first solid electrolyte layer and the second solid electrolyte layer are bipolar batteries larger than the positive electrode and the negative electrode. The bipolar battery according to claim 1, wherein
In the in-plane direction of the bipolar battery, the bipolar current collector foil is a bipolar battery larger than the first solid electrolyte layer and the second solid electrolyte layer. The bipolar battery according to claim 1, wherein
The unit cell has a third solid electrolyte layer disposed between the positive electrode and the negative electrode in the unit cell in the stacking direction of the bipolar battery,
In the in-plane direction of the bipolar battery, the third solid electrolyte layer is a bipolar battery that is larger than the positive electrode laminate and the negative electrode laminate. The bipolar battery according to claim 1, wherein
The bipolar battery has a plurality of the unit cells,
The plurality of unit cells are bipolar batteries connected in series by the bipolar electrode. The bipolar battery according to claim 1, wherein
The unit cell has a plurality of the positive electrode and the negative electrode,
A bipolar battery in which the plurality of positive electrodes and the plurality of negative electrodes are electrically connected in the unit cell.

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