BR102017019296B1 - COMPOSITE OF ELECTRODE, SECONDARY BATTERY AND BATTERY ASSEMBLY - Google Patents

Abstract

THE PRESENT INVENTION RELATES TO AN ELECTRODE COMPOSITE. THE ELECTRODE COMPOSITE INCLUDES A LAYER CONTAINING NEGATIVE ELECTRODE ACTIVE MATERIAL AND AN INSULATING PARTICLE LAYER. THE LAYER CONTAINING NEGATIVE ELECTRODE ACTIVE MATERIAL INCLUDES SECONDARY PARTICLES OF NEGATIVE ELECTRODE ACTIVE MATERIAL THAT HAVE AN AVERAGE SECONDARY PARTICLE SIZE OF 1 μM TO 30 μM. THE INSULATING PARTICLE LAYER IS PROVIDED ON THE LAYER CONTAINING NEGATIVE ELECTRODE ACTIVE MATERIAL. THE INSULATING PARTICLE LAYER INCLUDES A FIRST SURFACE AND A SECOND SURFACE OPPOSITE THE FIRST SURFACE. THE FIRST SURFACE IS IN CONTACT WITH THE LAYER CONTAINING NEGATIVE ELECTRODE ACTIVE MATERIAL. THE SECOND SURFACE HAS A SURFACE ROUGHNESS OF 0.1 μM OR LESS.

Description

FIELD

[001] Embodiments described in this document refer, in general, to an electrode composite, a secondary battery, a battery module, a battery pack and a vehicle.

BACKGROUND

[002] In recent years, secondary batteries such as lithium-ion secondary batteries have been developed as high-energy density batteries. Secondary batteries are expected as power sources for vehicles such as hybrid automobiles and electric automobiles, and as large power sources for electrical storage. In particular, for vehicle application, secondary batteries are required to have other performance such as fast charge and discharge performance and long-term reliability. Secondary batteries with fast charge and discharge capabilities have the advantage of a very short charge time. Furthermore, such a battery can improve motive force-related performances and also efficiently recover regenerative energy from the motive force in a hybrid or similar vehicle.

[003] Rapid charging and discharging is made possible by rapid movements of electrons and lithium ions between positive electrodes and negative electrodes. However, when a battery that uses carbon-based negative electrodes is repeatedly subjected to rapid charge and discharge, lithium metal dendrite precipitation may occur on the electrode. These dendrites can cause internal short circuits, thus resulting in heat generation and ignition.

[004] Therefore, batteries have been developed that use, as negative electrode active materials, composite metal oxides in place of carbonaceous materials. In particular, batteries that use titanium-containing oxides as active negative electrode materials have rapid charge and stable discharge capabilities, and also exhibit longer lifetimes when compared to carbon-based negative electrodes.

[005] However, such titanium-containing oxides have higher (more noble) potentials in relation to lithium metal when compared to carbonaceous materials. Furthermore, oxides containing titanium have low mass capacity. For these reasons, batteries that use these titanium-containing oxides have the problem of having low energy density.

[006] For example, the operating potential of an electrode that includes a spinel-type lithium titanate Li4Ti5O12 is approximately 1.5 V based on lithium metal, and higher (more noble) when compared to the potentials of carbon-based negative electrodes. The potential of lithium titanate is derived from a redox reaction between Ti3+ and Ti4+ in the electrochemical insertion and extraction of lithium and is thus electrochemically restricted. Additionally, fast lithium-ion charging and discharging can be done stably at a high electrode potential on the order of 1.5 V (vs. Li/Li+). Therefore, it is substantially difficult to lower the potential of the electrode including lithium titanate in order to improve the energy density.

[007] On the other hand, as well as in relation to capacity per unit mass, lithium and titanium composite oxides such as spinel-type lithium titanate Li4Ti5O12 have a theoretical capacity of about 175 mAh/g. On the other hand, common carbon-based electrode materials have a theoretical capacity of 372 mAh/g. Consequently, titanium-containing oxides are significantly inferior in capacity density when compared to carbon-based negative electrodes. This is due to the fact that the crystal structures of titanium-containing oxides have small numbers of sites into which lithium can be inserted, or lithium is easily stabilized in the structures, thereby decreasing substantial capacity.

BRIEF DESCRIPTION OF THE DRAWINGS

[008] Figure 1 is a schematic cross-sectional view of a first example of an electrode composite according to a first embodiment;

[009] Figure 2 is an enlarged cross-sectional view of a portion A of the electrode composite shown in Figure 1;

[010] Figure 3 is a schematic cross-sectional view of a second example of an electrode composite according to the first embodiment;

[011] Figure 4 is a schematic cross-sectional view of a first example of a secondary battery according to a second embodiment;

[012] Figure 5 is an enlarged cross-sectional view of a portion B of the secondary battery shown in Figure 4;

[013] Figure 6 is a partial sectional perspective view that schematically shows a second example of a secondary battery according to the second embodiment;

[014] Figure 7 is a schematic cross-sectional view of an assembly of a positive electrode and a negative electrode included in the secondary battery shown in Figure 6;

[015] Figure 8 is a schematic cross-sectional view of an example of a group of electrodes that can be included in a secondary battery according to the second embodiment;

[016] Figure 9 is a schematic cross-sectional view of another example of a group of electrodes that can be included in a secondary battery according to the second embodiment;

[017] Figure 10 is a perspective view that schematically shows an example of a battery module according to a third embodiment;

[018] Figure 11 is an exploded perspective view that schematically shows an example of a battery pack according to a fourth embodiment;

[019] Figure 12 is a block diagram showing an electrical circuit of the battery pack in Figure 11;

[020] Figure 13 is a schematic sectional view showing an example of a vehicle according to a fifth embodiment; It is

[021] Figure 14 is the schematic view showing another example of a vehicle according to the fifth embodiment.

DETAILED DESCRIPTION

[022] In general, according to one embodiment, an electrode composite is provided. The electrode composite includes a layer containing negative electrode active material and an insulating particle layer. The layer containing negative electrode active material includes secondary particles of negative electrode active material. An average secondary particle size of the negative electrode active material secondary particles is 1 μm to 30 μm. The insulating particle layer includes inorganic compound particles. The insulating particle layer is provided in the layer containing negative electrode active material. The insulating particle layer includes a first surface and a second surface opposite the first surface. The first surface is in contact with the layer containing negative electrode active material. A surface roughness of the second surface of the insulating particle layer is 0.1 μm or less.

[023] According to one embodiment, a secondary battery is provided. The secondary battery includes the electrode composite according to the embodiment and a positive electrode. The positive electrode includes a layer that contains positive electrode active material. The second surface of the insulating particle layer of the electrode composite is in contact with the layer containing positive electrode active material.

[024] According to one embodiment, a battery module is provided. The battery module includes secondary batteries, each according to the modality.

[025] According to one embodiment, a battery pack is provided. The battery pack includes the secondary battery depending on the mode.

[026] According to one embodiment, a vehicle is provided. The vehicle includes the battery pack depending on the modality.

[027] The modalities will be explained below with reference to the drawings. In this case, structures common across all modalities are represented by the same symbols and duplicate explanations will be omitted. Furthermore, each drawing is a typical view to explain the embodiments and to promote an understanding of the embodiments. Although there are different parts of a real device in shape, dimension and ratio, these structural designs can be appropriately changed taking into consideration the following known explanations and technologies.

(FIRST MODE)

[028] According to a first embodiment, an electrode composite is provided. The electrode composite includes a layer containing negative electrode active material and an insulating particle layer. The layer containing negative electrode active material includes secondary particles of negative electrode active material. An average secondary particle size of the negative electrode active material secondary particles is 1 μm to 30 μm. The insulating particle layer includes inorganic compound particles. The insulating particle layer is provided in the layer containing negative electrode active material. The insulating particle layer includes a first surface and a second surface opposite the first surface. The first surface is in contact with the layer containing negative electrode active material. A surface roughness of the second surface of the insulating particle layer is 0.1 μm or less.

[029] “Average secondary particle size” described below is the volume average secondary particle size. “Mean primary particle size” is the volume mean primary particle size. “Average particle size” of a mixture of primary particles and secondary particles is the volume average particle size of the mixture without distinction between primary particles and secondary particles.

[030] The layer containing negative electrode active material included in the electrode composite according to the first embodiment includes the secondary particles of negative electrode active material. The secondary particles of negative electrode active material may be, for example, agglomerates of primary particles of negative electrode active material. The secondary particles of negative electrode active material may be, for example, those obtained by granulating the primary particles of negative electrode active material with a binder or the like. Alternatively, the secondary negative electrode active material particles may be agglomerates of the primary negative electrode active material particles due to interaction or the like. Such a secondary particle of negative electrode active material may have a specific surface area smaller than the primary particle of negative electrode active material. Thus, in the secondary battery that can be designed using the electrode composite according to the first embodiment, it is possible to suppress side reactions between an electrolyte, for example a non-aqueous electrolyte, and the secondary particles of active electrode material. negative electrode on a surface of the layer containing negative electrode active material. Additionally, secondary particles of negative electrode active material can improve ease of handling when manufacturing an electrode. Furthermore, with the use of the negative electrode active material secondary particles it is possible to improve an electrode density and hope to design a secondary battery with the ability to exhibit a high energy density.

[031] The present inventors have repeatedly carried out test fabrication, in each of which an insulating particle layer was provided in a layer containing negative electrode active material, including such secondary particles of negative electrode active material to obtain a composite electrode, and the electrode composite was used to manufacture a secondary battery. As a result, the present inventors found that the secondary batteries actually produced through testing were poor in output performance.

[032] As a result of detailed analysis of this result, the present inventors found that, in the prototype secondary battery, an electrical short circuit partially occurs between the positive electrode and the negative electrode. As a result of the search for the cause of the electrical short circuit, it was found that the thickness of the insulating particle layer located between a layer containing negative electrode active material and the positive electrode (layer containing positive electrode active material) is not uniform. , and there is a portion in which a distance between the layer containing negative electrode active material and the positive electrode is noticeably small, and a physical contact between the positive electrode and the negative electrode occurs in the portion. It was also found that the reason why the thickness of the insulating particle layer is not uniform is that the surface roughness of a surface of the insulating particle layer in contact with the positive electrode is large, reflecting the particle size of the secondary particle of negative electrode active material.

[033] As a result of intensive studies based on this result, the present inventors designed the electrode composite according to the first modality.

[034] The electrode composite according to the first embodiment includes a layer containing negative electrode active material and an insulating particle layer provided in the layer containing negative electrode active material. The insulating particle layer has a first surface and a second surface opposite the first surface. That is, the second surface can be termed as a reverse surface relative to the first surface. The first surface is in contact with the layer containing negative electrode active material. The second surface of the insulating particle layer can also be referred to as the surface of the electrode composite. The second surface of the insulating particle layer may be in contact with the positive electrode in the secondary battery.

[035] In the electrode composite according to the first embodiment, although the average secondary particle size of the negative electrode active material secondary particles included in the layer containing negative electrode active material is 1 μm to 30 μm, the roughness surface area of the second surface of the insulating particle layer formed thereon is 0.1 μm or less. The insulating particle layer in which the surface roughness of the second surface is within this range may have a more uniform thickness. In the secondary battery produced using the electrode composite according to the first embodiment, such an insulating particle layer can prevent a physical contact between the layer containing negative electrode active material and the positive electrode (e.g., the layer containing positive electrode active material).

[036] In such a secondary battery, since the layer containing negative electrode active material includes secondary particles of negative electrode active material that have an average secondary particle size of 1 μm to 30 μm, side reactions between the secondary particles of active material of negative electrode and electrolyte may be suppressed due to the reason described above.

[037] Electrical short circuit and side reactions between the secondary particles of negative electrode active material and the electrolyte are factors that decrease the output performance of the secondary battery. Since the electrode composite according to the first embodiment can suppress these factors, a secondary battery capable of exhibiting excellent output performance can be designed.

[038] In the following, an electrode structure according to the first embodiment will be described in more detail.

[039] The electrode composite according to the first embodiment includes a layer containing negative electrode active material and an insulating particle layer provided in the layer containing negative electrode active material.

[040] The electrode composite according to the first embodiment may include a negative electrode that includes the layer containing negative electrode active material, or an electrode that has a bipolar structure that includes the layer containing negative electrode active material and a layer containing positive electrode active material.

[041] The negative electrode may additionally include a negative electrode current collector. The negative electrode current collector may have a flat belt-like shape that has, for example, one surface and the other surface as an opposite surface thereof (a reverse surface relative to a surface). The layer containing negative electrode active material may be provided on both surfaces of the negative electrode current collector, or may be provided on one of the surfaces. The negative electrode current collector may include a portion that does not support the layer containing negative electrode active material on any surface. This portion can serve as a negative electrode flap, for example.

[042] The electrode having the bipolar structure may additionally include a current collector. The current collector may have a flat belt-like shape that has two surfaces, for example, a third surface and a fourth surface opposite the third surface. That is, the fourth surface is a reverse surface relative to the third surface. The layer containing negative electrode active material can be provided on the third surface of the current collector. The layer containing positive electrode active material can be provided on the fourth surface of the current collector. The current collector may include a portion that does not support the active material-containing layer (the negative electrode active material-containing layer or the positive electrode active material-containing layer) on any surface. This portion can serve as an electrode tab, for example.

[043] The layer containing negative electrode active material includes secondary particles of negative electrode active material. The layer containing negative electrode active material may additionally include primary particles of negative electrode active material.

[044] The average secondary particle size of the negative electrode active material secondary particles is 1 μm to 30 μm.

[045] Secondary negative electrode active material particles that have an average secondary particle size of less than 1 μm have a very large specific surface area. Such secondary negative electrode active material particles tend to cause side reactions with the electrolyte in the secondary battery, and as a result, the output performance of the secondary battery deteriorates. On the other hand, in the layer containing negative electrode active material that includes secondary particles of negative electrode active material having an average secondary particle size of more than 30 μm, the surface roughness of a coated film becomes very large, for example when the film is formed by coating. It is difficult for this coated film to form a layer containing negative electrode active material that has a small surface roughness even if the film is subjected to treatment such as pressing. In particular, for the purpose of high output, a layer containing negative electrode active material with a small thickness can be produced. In such a case, a coated film including negative electrode active material secondary particles having an average secondary particle size of more than 30 μm must be subjected to a pressing or similar step with a large pressing pressure; however, due to these processes, a problem such as disintegration of secondary particles is likely to occur.

[046] The average secondary particle size of the negative electrode active material secondary particles is preferably 5 μm to 15 μm. If such preferential secondary particles of negative electrode active material are used, even when a coated film including such particles is pressed at a relatively high pressure for the purpose of high output, while preventing disintegration of secondary particles, a layer containing material active negative electrode that has a small surface roughness can be produced. The average secondary particle size of the negative electrode active material secondary particles is more preferably 8 μm to 15 μm.

[047] When the layer containing negative electrode active material includes the primary particles of negative electrode active material, the average primary particle size of the primary particles is preferably 0.1 μm to 10 μm, and more preferably 1 μm at 5μm. For the primary particles that also constitute the secondary particles, the average primary particle size of the primary particles is preferably 0.1 μm to 10 μm, and more preferably 1 μm to 5 μm. It is desirable that the average primary particle size of the primary particles be within this range, due to handling during production secondary particles and loss in the same process can be suppressed.

[048] A specific BET surface area of the secondary particles of negative electrode active material is preferably 5 m2/g to 100 m2/g. Considering the management of active materials and a mixing property with a conductive agent and a binder, the BET specific surface area of the negative electrode active material secondary particle is more preferably 5 m2/g to 20 m2/g.

[049] The layer containing negative electrode active material may additionally include a conductive agent and a binder. The conductive agent may be, for example, conductive agent particles.

[050] A surface of the layer containing negative electrode active material in contact with the first surface of the insulating particle layer may have a recess. Such an indentation may be, for example, a gap between secondary particles of negative electrode active material exposed on a surface of the layer containing negative electrode active material, a gap between particles of conducting agent exposed on a surface of the layer containing negative electrode active material negative electrode active material, and/or a gap between a secondary particle of negative electrode active material and a particle of conductive agent that are exposed on a surface of the layer containing negative electrode active material.

[051] The layer containing positive electrode active material may include, for example, positive electrode active material particles, a conductive agent and a binder.

[052] The insulating particle layer has a first surface and a second surface opposite the first surface. The first surface is in contact with the layer containing negative electrode active material.

[053] The surface roughness of the second surface of the insulating particle layer is 0.1 μm or less. The surface roughness of the second surface is, for example, 0.05 μm to 0.1 μm. The surface roughness of the second surface is preferably 0.05 μm to 0.08 μm. Within this range, the probability of short circuit can be decreased and the electrolyte can be sufficiently filled, so that more excellent output performance can be conceived.

[054] It is preferred that the surface roughness of the first surface of the insulating particle layer, that is, the surface in contact with the layer containing negative electrode active material, is 5 μm or less. Since the insulating particle layer in which the surface roughness of the first surface is within this range can have a more uniform thickness, more excellent output performance can be designed. The surface roughness of the first surface is more preferably 0.5 μm or more and 5 μm. The insulating particle layer in which the surface roughness of the first surface is 0.5 μm to 5 μm can take a state in which the insulating particle layer can cover the surface of the layer containing negative electrode active material while isolating the Particles included in the insulating particle layer sufficiently enter the recess that may exist on the surface of the layer containing negative electrode active material. Such an insulating particle layer can achieve more excellent electrical insulation between the layer containing negative electrode active material and the positive electrode (for example, the layer containing active material of positive electrode), and electrical short circuit between them can be more sufficiently suppressed.

[055] The thickness of the insulating particle layer is preferably 10 μm to 40 μm. Among the electrode composites according to the first embodiment, an electrode composite that includes an insulating particle layer having a thickness within the preferred range can sufficiently suppress electrical short circuit between the layer containing negative electrode active material and the positive electrode (e.g., a layer containing positive electrode active material) while suppressing a resistance value. The thickness of the insulating particle layer is most preferably 10 μm to 30 μm.

[056] The insulating particle layer includes inorganic compound particles. The inorganic compound particles preferably include particles of a lithium ion conductive substance (lithium ion conductive particles). The inorganic compound particles may consist of particles of a lithium ion conducting substance.

[057] Inorganic compound particles may include, for example, particles of a first group that have a first average particle size and particles of a second group that have a second average particle size greater than the first average particle size . The first surface of the insulating particle layer preferably includes at least a portion of the particles of the first group. In this preferred aspect, the inorganic compound particles of the first group can fill the previously described recesses on the surface of the layer containing negative electrode active material. It is preferred that the inorganic compound particles of the second group are present in a portion closer to the second surface of the insulating particle layer relative to the inorganic compound particles of the first group. In this preferred aspect, since the insulating particle layer includes the inorganic compound particles of the second group, which have a large particle size, a sufficient space capable of holding, for example, a liquid non-aqueous electrolyte and/or an electrolyte Non-aqueous gel is provided.

[058] The first average particle size is preferably 0.01 μm to 10 μm and more preferably 0.05 μm to 3 μm. The second average particle size is preferably 15 μm to 30 μm and more preferably 15 μm to 25 μm.

[059] The inorganic compound particles of the first group preferably have a d10 particle size of 30% or less of the average particle size and a d90 particle size of 1.5 times or less of the average particle size. Similarly, the inorganic compound particles of the second group preferably have a d10 particle size of 30% or less of the average particle size and a d90 particle size of 1.5 times or less of the average particle size. Here, the particle size d10 is the particle size at which a cumulative frequency of a small particle size side is 10% in a cumulative particle size curve of the particles. Particle size d90 is the particle size at which the cumulative frequency of the small particle size side is 90% on the cumulative particle size curve of the particles.

[060] The insulating particle layer may include a binder, for example.

[061] Materials that can be used in an electrode composite according to the first embodiment will be described in detail below.

(1) NEGATIVE ELECTRODE

[062] The negative electrode current collector is preferably aluminum foil, or aluminum alloy foil containing at least one element selected from Mg, Ti, Zn, Mn, Fe, Cu and Si. The crystal particle size average of aluminum foil and aluminum alloy foil is preferably 50 μm or less. This results in allowing the current collector to exhibit drastically improved strength and the negative electrode to undergo an increase in density at high pressing pressure, and thereby allowing the capacity of the battery to be increased. Furthermore, deterioration of the negative electrode current collector due to melting or corrosion due to overload cycle under high temperature environment (40 °C or more) can be avoided. Therefore, an increase in impedance of the negative electrode can be suppressed. Furthermore, the output characteristics, fast charge characteristics, charge and discharge cycle characteristics can also be improved. The average crystal particle size of the negative electrode current collector is more preferably 30 μm or less, more preferably 5 μm or less.

[063] The preceding average crystal particle sizes of aluminum foil and aluminum alloy foil are affected in a complex manner by many factors, such as material structure, impurities, processing conditions, heat treatment hysterisis, and processing conditions. annealing. The crystal particle size (diameter) of aluminum foil or aluminum alloy foil can be adjusted to 50 μm or less by combining the previously mentioned factors in the manufacturing process.

[064] The average crystal particle size is obtained as follows. The surface texture of the current collector is subjected to texture observation with an optical microscope, thereby finding the number n of crystal particles present at 1 mm x 1 mm. The average crystal particle area S is obtained from S = 1 x 106/n (μm2) using the number n. From the obtained value of S, the average crystal particle size d (μm) is calculated according to formula (A) below.

[065] Aluminum foil and aluminum alloy foil are, for example, 20 μm or less, more preferably 15 μm thick. The aluminum foil preferably has a purity of 99% by mass or more. An alloy containing an element such as magnesium, zinc and silicon is preferred such as aluminum alloy. On the other hand, the content of a transition metal such as iron, copper, nickel, and chromium is preferably 1% by mass or less.

[066] The secondary particles of negative electrode active material preferably include titanium-containing oxide particles. Titanium-containing oxide particles are not particularly limited as long as the particles can have lithium inserted and extracted. For example, a titanium-niobium composite oxide, a lithium titanate that has a spinel-type crystal structure, a lithium titanate that has a ramsdelite-type crystal structure, other metal composite oxides that contain titanium, a titanium dioxides which have a monoclinic crystal structure (TiO2(B)), and titanium dioxides which have an anatase-type crystal structure can be used. That is, the titanium-containing oxide particle may include, for example, at least one type of particles selected from the group consisting of lithium titanate particles having the spinel-type crystal structure, lithium titanate particles having the ramsdelite-type crystal structure, titanium-niobium composite oxide particles, titanium dioxide particles that have the monoclinic crystal structure, and titanium dioxide particles that have the anatase-type crystal structure.

[067] The titanium-niobium composite oxide may include, for example, a group of compounds represented by a general formula of LixTi1-yM1yNb2-zM2zO7. Here, x is a value that varies within a range of 0 < x < 5 depending on the charge and discharge reactions. Additionally, M1 can be at least one selected from the group consisting of Zr, Si and Sn. M2 can be at least one selected from the group consisting of V, Ta, and Bi. y is a value that satisfies 0 < y < 1. z is a value that satisfies 0 < z < 2. M1 may be one selected from the group consisting of Zr, Si and Sn include two selected from the group consisting of Zr, Si and Sn, or include Zr, Si and Sn. Similarly, M2 may be one selected from the group consisting of V, Ta, and Bi, include two selected from the group consisting of V, Ta, and Bi, or include V, Ta, and Bi.

[068] Preferred examples of the titanium-niobium composite oxide include Nb2TiO7, Nb2Ti2O9, Nb10Ti2O9, Nb24TiO64, Nb14TiO37, and Nb2TiO9. Such composite oxides may be substituted titanium-niobium composite oxides in which at least part of the Nb and/or Ti is replaced by another element (or elements). Examples of a replacement element (another element) include V, Cr, Mo, Ta, Zr, Mn, Fe, Mg, B, Pb, and Al. The replacement element may be one element, or it may be a combination of two or more of the same.

[069] The negative electrode active material secondary particles may include one type of titanium-niobium composite oxide particle or may include particles of plural types of titanium-niobium composite oxides. In particular, it is preferred that the secondary particles of negative electrode active material include particles of a titanium composite oxide having a monoclinic crystal structure (e.g., having a composition represented by Nb2TiO7). In particular, the active material particles including the titanium-niobium composite oxide may include secondary particles as clusters of primary particles. The active material particles preferably include the secondary particles and a carbon-containing layer, e.g., carbon coating, which covers at least a portion of the surface of the secondary particles. The carbon-containing layer may cover a surface of each primary particle or may cover the surface of the secondary particle. Since an electrode using an active material particle containing the carbon-containing layer has enhanced electron conductivity, a large current flows easily. Additionally, the carbon-containing layer covering at least a portion of the surface of the active material can suppress overvoltage generated when charging and discharging are repeated. As a result, an excellent cycle life can be designed.

[070] Like lithium titanate, which has a spinel-type crystal structure, a compound represented by a general formula of LÍ4+xTÍ50i2, in which x varies within a range of -1 < x < 3 depending on charge reactions and discharge, and the like may be cited. Like lithium titanate which has a ramsdelite-type crystal structure, a compound represented by a general formula of Li2+yTi3O7, where y varies within a range of -1 < y < 3 depending on charge and discharge reactions, and the like can be cited. TiO2 (B) and anatase-type titanium dioxide may additionally include Li due to loading. Therefore, this titanium dioxide can have a composition represented by, for example, Li1+zTiO2, where z varies within a range of -1 < z < 0, depending on the charge and discharge reactions.

[071] Examples of other composite metal oxides that contain titanium include composite metal oxides that include Ti and at least one element selected from the group consisting of P, V, Sn, Cu, Ni, and Fe. Examples of such an oxide Metal composites include TiO2-P2O5, TiO2-V2O5, TiO2-P2O5-SnO2, and TiO2-P2O5-MeO (Me is at least one element selected from the group consisting of Cu, Ni, and Fe).

[072] Such composite metal oxide preferably has low crystallinity, and has a microstructure in which a crystal phase coexists with an amorphous phase, or a microstructure in which an amorphous phase exists alone. By having the microstructure, cycle performance can be substantially improved.

[073] The secondary negative electrode active material particles may consist of titanium-containing oxide particles, be a mixture of titanium-containing oxide particles and particles of a negative electrode active material other than the titanium-containing oxide, or consist into particles of a negative electrode active material other than titanium-containing oxide. However, a mass ratio of titanium-containing oxide particles to the total amount of secondary negative electrode active material particles is preferably 50 mass % or more.

[074] As a negative electrode active material other than titanium-containing oxide, a compound that allows lithium ions to be inserted into it and extracted from it can be used. Examples of the compounds include oxides (composite oxides), sulfides, and nitrides. These compounds also include metal compounds that do not include lithium in uncharged states, but come to include lithium upon charging.

[075] Such oxides include amorphous tin oxides such as, for example, SnB0.4P0.6O3.1, tin and silicon oxides such as, for example, SnSiO3, silicon oxides such as, for example, SiO, and oxides of tungsten such as, for example, WO3.

[076] As an additional negative electrode active material, an oxide containing niobium can be cited. Examples of the niobium-containing oxide include a niobium oxide (e.g. Nb2O5), and a composite oxide of niobium and titanium that has a monoclinic crystal structure (e.g. Nb2TiO7) that exhibits a more noble lithium insertion and extraction potential than than 1.0 V with respect to the potential of lithium metal.

[077] Other examples of the oxide include composite oxides that have an orthorhombic crystal structure and a composition represented by a general formula (1) or (2) below: wherein M1 is at least one selected from the group consisting of Sr, Ba, Ca, and Mg; M2 is at least one selected from the group consisting of Cs, K, and Na; M3 is at least one selected from the group consisting of Al, Fe, Zr, Sn, V, Nb, Ta, and Mo; the subscripts are within the range of 2 < a < 6, 0 < b < 1, 0 < c^6, and -0.5 < d <0.5; M1 may include one selected from the group consisting of Sr, Ba, Ca, and Mg, or a combination of two or more selected from that group; M2 may include one selected from the group consisting of Cs, K, and Na, or a combination of two or more selected from that group; M3 may include one selected from the group consisting of Al, Fe, Zr, Sn, V, Nb, Ta, and Mo, or a combination of two or more selected from that group; wherein Mα is at least one selected from the group consisting of Cs and K; Mβ is at least one selected from the group consisting of Zr, Sn, V, Nb, Ta, Mo, W, Fe, Co, Mn, and Al; the subscriptions are within the range 0 < w < 4, 0 < e < 2, 0 < f < 2, 0 < g < 6, and -0.5 < h <0.5; Mα may be one of Cs and K, or may include both Cs and K; Mβ may include one selected from the group consisting of Zr, Sn, V, Nb, Ta, Mo, W, Fe, Co, Mn, and Al, or a combination of two or more selected from the group consisting of Zr, Sn, V, Nb, Ta, Mo, W, Fe, Co, Mn, and Al.

[078] The composite oxide represented by general formula (1) or (2) preferably includes Nb. The preferred composite oxide can be termed as a niobium-containing composite oxide that has an orthorhombic crystal structure.

[079] These composite oxides exhibit a small volume change due to the insertion and extraction of lithium. Additionally, these composite oxides exhibit a lower operational potential than lithium titanate which has a spinel-type structure. Therefore, the secondary battery that includes an electrode that includes any of these composite oxides as a negative electrode can exhibit a higher battery voltage than a secondary battery that includes lithium titanate that has the spinel-type structure as a negative electrode. Additionally, these composite oxides exhibit a charge curve and a discharge curve in each of which the potential changes with a significant gradient without the step of the potential in the potential operating range. Therefore, in the secondary battery that includes any of these composite oxides, the state of charge can be easily captured based on the voltage change.

[080] The niobium-containing composite oxide that has the orthorhombic crystal structure most preferably additionally includes Na.

[081] It should be noted that the composite oxide represented by general formula (1) or (2) includes a composite oxide that includes Nb and Ti. As a specific example, a composite oxide represented by general formula (1) can be cited, wherein the subscript c is within a range of 0 < c < 6 and M3 is Nb or a combination of Nb and at least one selected from the group consisting of Al, Fe, Zr, Sn, V, Ta, and Mo . As another specific example, there may be cited a composite oxide represented by the general formula (2), in which the subscript g is within a range of 0 < g < 6 and Mβ is Nb or a combination of Nb and at least one selected from among the group consisting of Zr, Sn, V, Ta, Mo, W, Fe, Co, Mn, and Al. Each of these composite oxides can also be termed as a composite oxide containing titanium and niobium that has a crystal structure orthorhombic. These composite oxides are also included in titanium-containing oxides, and are further included in titanium-niobium composite oxides.

[082] Examples of sulfides include a titanium sulfide such as TiS2, a molybdenum sulfide such as MoS2, an iron sulfide such as FeS, FeS2, and LixFeS2.

[083] Examples of nitrides include lithium cobalt nitride (e.g., LixCoyN, 0 < x < 4, 0 < y < 0.5).

[084] The conductive agent is added, if necessary, in order to improve the current collection performance and reduce the contact resistance between the active material and the current collector. Examples of the conducting agent include carbonaceous substances such as acetylene black, Ketjen black, graphite and/or coke.

[085] As the binder, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), a cellulose-containing component such as sodium carboxymethyl cellulose (CMC), a fluorine-containing rubber or a styrene butadiene rubber can be, without limitation, used.

[086] The negative electrode active material, the conductive agent, and the binder are preferably mixed respectively in proportions of: 80% by mass to 98% by mass; 0% by mass to 20% by mass; and 2% by mass to 7% by mass. The amount of binder, adjusted to 2% by mass or more, provides a sufficient binder property between the layer containing negative electrode active material and the negative electrode current collector, thereby achieving high cycle characteristics. On the other hand, from the perspective of increasing capacity, the amount of the conducting agent is preferably 20% by mass or less, and the amount of the binder is preferably 7% by mass or less.

[087] A density of the layer containing negative electrode active material is preferably 1.8 g/cm3 to 2.5 g/cm3.

[088] Additionally, the layer containing negative electrode active material may also include a substance that emits fluorescence during exposure to ultraviolet rays. For example, such a fluorescent substance may be included in a negative electrode slurry to be applied to the negative electrode current collector. The fluorescent substance can be mixed with a negative electrode slurry in an amount of 1% by mass to 3% by mass relative to a mass of the negative electrode active material.

[089] Examples of the fluorescent substance include potassium halophosphate altered with Sb and Mn, ZnS altered with Ag, Zn2SiO4 altered with Mn, and ZnCdS altered with Ag.

(2) ELECTRODE THAT HAS BIPOLAR STRUCTURE

[090] As a current collector that can be included in an electrode that has the bipolar structure, a current collector that can be used as a negative electrode current collector described above can be used.

[091] As materials of the layer containing negative electrode active material included in the electrode having the bipolar structure, the same materials as those of the layer containing negative electrode active material included in the negative electrode described above can be used.

[092] The layer containing positive electrode active material may include a positive electrode active material, a conductive agent and a binder, as described above.

[093] Examples of the positive electrode active material include an oxide, a composite oxide and polymer, each of which allows lithium ions to be inserted into it and extracted from it.

[094] Examples of the oxide and composite oxide include a manganese dioxide (MnO2), an iron oxide, a copper oxide, a nickel oxide, a lithium manganese composite oxide (e.g., LixMn2-yMyO4 or LixMn1- yMyO2), a composite oxide of lithium and nickel (e.g., LixNi1-xMyO2), a composite oxide of lithium and cobalt (LixCo1-yMyO2), a composite oxide of lithium, nickel and cobalt (e.g., LixNi1-y-zCoyMzO2 ), a lithium phosphate compound that has an olivine-type crystal structure (e.g., LixFePO4, LixFe1-yMnyPO4, LixCoPO4 and the like), a composite oxide of lithium, manganese and cobalt (e.g., LixMn1-y-zCoyMzO2 ), a composite oxide of lithium, manganese, and nickel (e.g., LixMnaNibMcO2 (a + b + c = 1), e.g., LixMn1/2Ni1/2O2), a composite oxide of lithium, manganese, and nickel that has a spinel-type crystal (LixMn2-yNiyO4), a composite oxide of lithium, nickel, cobalt, and manganese (e.g., LixMn1/3Ni1/3Co1/3O2), an iron sulfate (Fe2(SO4)3), and an oxide of vanadium (e.g. V2O5). As the positive electrode active material, these compounds can be used singly, or two or more compounds can be used in combination.

[095] It should be noted that, when the compounds mentioned above are not particularly defined, x, y, and z are preferably and respectively within the ranges of 0 to 1.2, 0 to 0.5, and 0 to 0.1. Additionally, M represents at least one element selected from the group consisting of Co, Mn, Ni, Al, Cr, Fe, Mg, Zn, Zr, Sn, Cu, and Fe. Here, M may be an element selected from the group consisting of Co, Mn, Ni, Al, Cr, Fe, Mg, Zn, Zr, Sn, Cu, and Fe. Alternatively, M may be a combination of two or more elements selected from the group consisting of Co, Mn, Ni, Al, Cr, Fe, Mg, Zn, Zr, Sn, Cu, and Fe.

[096] The positive electrode active material preferably includes at least one selected from the group consisting of the lithium phosphate compound having the olivine-type crystal structure, the composite oxide of lithium and manganese, the composite oxide of lithium and nickel, the composite oxide of lithium and cobalt, the composite oxide of lithium, nickel and cobalt, the composite oxide of lithium, manganese and nickel, the composite oxide of lithium, manganese and nickel which has the spinel-type crystal structure, and the composite oxide of lithium, manganese and cobalt. Using the compounds described above as the positive electrode active materials can achieve high battery voltage.

[097] As the polymer, for example, conductive polymer materials such as polyaniline and polypyrrole, or disulfide polymer materials can be used. Sulfur (S) or fluorocarbon can also be used as the active material.

[098] The positive active material is, for example, in a particle format. Particles can be primary particles or secondary particles such as clusters of primary particles.

[099] The positive electrode active material preferably has a BET specific surface area of 0.1 m2/g to 10 m2/g. Positive electrode active material particles with a specific surface area of 0.1 m2/g or more can sufficiently guarantee insertion and extraction sites for lithium ions. Positive electrode active material particles with a specific surface area of 10 m2/g or less are easily handled for industrial production, and can ensure favorable charge and discharge cycle performance. The method for measuring the specific surface area of BET will be described later.

[100] The conductive agent is added, if necessary, in order to improve the current collection performance and reduce the contact resistance between the active material and the current collector. Examples of the conducting agent include carbonaceous substances such as acetylene black, Ketjen black, graphite and/or coke.

[101] As the binder, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), a cellulose-containing component, for example, sodium carboxymethyl cellulose (CMC), a fluorine-containing rubber or a butadiene rubber Styrene may be, without limitation thereto, used.

[102] The positive electrode active material, the conductive agent, and the binder are preferably mixed respectively in proportions of: 73% by mass to 95% by mass; 3% by mass to 20% by mass; and 2% by mass to 7% by mass. The amount of the conducting agent is adjusted to 3% by mass or more, thus making it possible to achieve the effect described above. The amount of conductive agent, adjusted to 20% by mass or less, can reduce the decomposition of non-aqueous electrolyte on the surface of the conductive agent under high temperature storage. The amount of binder is adjusted to 2% by mass or more, thus providing sufficient electrode strength. The amount of binder is adjusted to 7% by mass or less, the mixing amount of binder as an insulating material in the electrode can be reduced, and the internal resistance can be reduced.

(3) INSULATING PARTICLE LAYER

[103] As described above, the inorganic compound particles included in the insulating particle layer preferably include particles of a lithium ion conductive substance (lithium ion conductive particles).

[104] Examples of materials that have lithium-ion conductivity include La0.51Li0.34TiO2.94, Li1.3Al0.3Ti1.7(PO4), Li7La3Zr2O12, a mixture of Li4SiO4 and Li3BO3 in a mass ratio of 50:50 , Li2.9PO3.3N0.4 (LIPON), Li3.6Si0.6P0.4O4, Li1.07Al0.69Ti1.46(PO4), and Li1.5Al0.5Ge1.5(PO4). The particles of these lithium ion conductive materials can also be termed as solid electrolyte particles.

[105] Inorganic compound particles may be those that have non-electrical conductivity (electrical insulation property). For example, inorganic compound particles may include oxide particles such as silica (e.g., SiO2) and alumina (e.g., Al2O3), nitride particles such as aluminum nitride and silicon nitride, or fine ionic crystal particles. slightly soluble. Examples of fine, slightly soluble ionic crystal particles include salt particles such as calcium fluoride, barium fluoride and barium sulfate, covalent crystal particles such as silicon particles, and fine clay particles such as montmorillonite and kaolinite.

[106] The mass ratio of the lithium ion non-conductive material particles to the inorganic compound particles is preferably 30 mass% or more, and more preferably 50 mass% or more. More preferably, the inorganic compound particles consist of the particles of the lithium ion non-conducting material.

[107] Examples of a binder that may be contained in the insulating particle layer include, but are not limited to, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and a cellulose-containing component such as sodium carboxymethyl cellulose (CMC). -Na), fluorine-containing rubber or styrene butadiene rubber.

[PRODUCTION METHOD]

[108] The electrode composite according to the first embodiment can be produced by the following procedure, for example.

[109] First, secondary particles of negative electrode active material, a conducting agent and a binder are provided. They are placed in a suitable dispersion solvent and stirred to prepare a negative electrode slurry. As the dispersion solvent, water, N-methyl-2-pyrolidone (NMP), and toluene can be used, for example.

[110] On the other hand, a current collector is provided. Negative electrode slurry is applied to both or one surface of the current collector. As a coater, for example, a mold coater, a curtain coater, a spray coater, an gravure coater, a coater that uses flexography, or a knife coater can be used, for example. An obtained coated film is dried and then pressed together with the current collector. In this way, a layer containing negative electrode active material can be obtained.

[111] Next, inorganic compound particles and a binder for an insulating particle layer are provided. As inorganic compound particles provided herein, it is preferred to use particles that have an average particle size of 0.1 μm to 10 μm and in which the particle size d10 is 30% or less of the average particle size, and the size of d90 particle is 1.5 times or less the average particle size. They are placed in a suitable dispersion solvent and stirred to prepare a first aqueous slurry. As the dispersion solvent, water, N-methyl-2-pyrolidone (NMP), and toluene can be used, for example.

[112] Then, the first aqueous paste is coated on the layer containing negative electrode active material. As a coater, a spray coater and an gravure coater can be used, for example. Particles of a first group contained in the first aqueous paste may enter the exposed recesses in a surface of the layer containing negative electrode active material. Then, an obtained coated film was dried. In this way, a first portion of the insulating particle layer is obtained.

[113] Next, other inorganic compound particles and a binder for an insulating particle layer are provided. The inorganic compound particles provided here are used as particles of a second group that have a larger average particle size than that of the particles of the first group. For example, the average particle size of particles in the second group may be 15 μm to 30 μm. As for particles in the second group, it is preferred to use particles that have a particle size distribution in which the particle size d10 is 30% or less of the average particle size and the particle size d90 is 1.5 times or less the size of average particle. They are placed in a suitable dispersion solvent and stirred to prepare a second aqueous slurry. As the dispersion solvent, water, N-methyl-2-pyrolidone (NMP), and toluene can be used, for example.

[114] Then, the second aqueous paste is coated on the first portion of the insulating particle layer. As a coater, a spray coater and an gravure coater can be used, for example. Then, an obtained coated film was dried. In this way, a second portion of the insulating particle layer is obtained.

[115] Then, pressing is carried out over the second portion of the insulating particle layer towards the current collector. In this way, it is possible to obtain an electrode composite that includes a layer containing negative electrode active material and an insulating particle layer provided therein.

[116] The surface roughness of a second surface of the insulating particle layer can be controlled by adjusting, for example, the average secondary particle size of the secondary particles of negative electrode active material, the average particle size of the particles of the first group, the average particle size of the particles of the second group, pressing conditions of the layer containing negative electrode active material, and pressing conditions of the insulating particle layer. Specific examples of the conditions are shown in the examples below.

[117] An electrode composite that includes an electrode that has the bipolar structure can be produced by the same procedure as described above, except for the following points.

[118] In the method of this example, first, positive electrode active material particles and a conductive agent and a binder that are for a layer containing positive electrode active material are also provided. They are placed in a suitable dispersion solvent and stirred to prepare an aqueous positive electrode slurry.

[119] In the method of this example, a current collector for a bipolar electrode is provided. The negative electrode slurry described above is applied to one surface (third surface) of the current collector, and a coated film obtained is dried. Then, the positive electrode aqueous paste is applied to the other surface (fourth surface) of the current collector, and an obtained coated film is dried. Then, the dried coated films are pressed together with the current collector. In this way, it is possible to obtain an electrode that has a bipolar structure and that includes the current collector, a layer containing negative electrode active material provided on the third surface of the current collector, and a layer containing positive electrode active material provided on the fourth surface of the current collector.

[120] By the same procedure as described above, an insulating particle layer is provided on the layer containing negative electrode active material of the electrode thus obtained. In this way, it is possible to obtain an electrode composite that includes an electrode having the bipolar structure and an insulating particle layer provided in the layer containing negative electrode active material of the electrode.

[121] When the fluorescent substance described above is contained in the negative electrode slurry, for example, after pressing the insulating particle layer, ultraviolet rays are irradiated on the insulating particle layer, in which the electrical insulating property of the particle layer insulation can be judged. Specifically, if there is a portion that emits light upon irradiation with ultraviolet rays, it is possible to judge that the electrical insulating property of the portion is not sufficient. As an ultraviolet irradiation device, a UV/BLUE lamp (trademark: TITAN TP-8000) manufactured by Spectronics Corporation can be used, for example.

[MEASUREMENT METHOD] (INSULATING PARTICLE LAYER SURFACE ROUGHNESS MEASUREMENT METHOD)

[122] A method of measuring the surface roughness of a second surface of an insulating particle layer included in an electrode composite incorporated in a battery will be described below.

[123] First, the battery to be measured is discharged until the remaining capacity reaches 0%. Then, the discharged battery is placed in a glove box under an inert atmosphere. Inside this glove box, the battery container member is opened carefully so as not to create an electrical short circuit between the positive electrode and the negative electrode. An electrode connected to a negative electrode terminal is cut off therefrom. When an insulating particle layer is present on a surface of the cut electrode, there is a possibility that the cut electrode is the electrode composite according to the first embodiment.

[124] Next, the cut electrode is placed in a container filled with methyl ethyl carbonate (MEC) and washed. After washing, the electrode is removed and then vacuum dried. In this way, methyl ethyl carbonate remaining on the electrode can be removed. The surface roughness is measured for the electrode subjected to such treatment.

[125] Such measurement can be carried out using, for example, the SJ-310 Portable Surface Roughness Measurement Surftest produced by Mitutoyo Corporation. In measurement, a surface opposite to a surface to be measured (the second surface of the insulating particle layer) is attached to a smooth plate with double-sided tape or the like for measurement. The measurement is performed five times with a cutoff value set to 0.25 mm. When the surface roughness Ra is more than 0.1 μm, the cutoff value is set to 0.8 mm. An average value of five measurement results is taken as the surface roughness Ra of the second surface of the insulating particle layer.

(OBSERVATION OF THE LAYER CONTAINING ACTIVE NEGATIVE ELECTRODE MATERIAL AND THE INSULATING PARTICLE LAYER)

[126] The presence, composition, and average particle size of the inorganic compound particles included in the insulating particle layer, and the composition, shape, and average particle size of the negative electrode active material secondary particles included in the material-containing layer active negative electrode can be examined by observing a cross-sectional structure of the electrode composite cut from the battery, as described above, with the use of a scanning electron microscope with an element analysis device (SEM-EDX: Microscopy Scanning Electron - Energy Dispersive X-ray Spectroscopy). That is, according to the observation with SEM-EDX, it is possible to judge whether or not the layer containing negative electrode active material includes secondary particles of negative electrode active material. 50 secondary particles of negative electrode active material are selected from a SEM image of the layer containing negative electrode active material, and a volume average secondary particle size can be measured from the selected secondary particles. The average primary particle size of the primary particles included in the layer containing negative electrode active material and the average particle size of particles included in each portion of the insulating particle layer can be measured in the same manner.

[127] The thickness of the insulating particle layer can be measured from a cross-sectional image of the electrode composite obtained by observation with the scanning electron microscope. A distance from the second surface to the first surface of the insulating particle layer is measured at ten points, and the average value thereof is taken as the thickness of the insulating particle layer. Of the ten points, five points are measured with a protrusion on a surface of the layer containing negative electrode active material as the first surface, and the remaining five points are measured with a recess on the surface of the layer containing negative electrode active material as the first surface. the first surface.

(METHOD OF MEASUREMENT OF BET-SPECIFIC SURFACE AREA OF ACTIVE MATERIAL)

[128] The BET specific surface area of the active material can be measured by the method described below, for example.

[129] The mass of active material is 4 g. For example, a 1.27 cm (1/2 inch) evaluation cell is used. As a pretreatment method, the evaluation cell is dried under reduced pressure at a temperature of about 100 °C or higher for 15 hours, at which gasification treatment is carried out. As a measuring device, Tristar II 3020 manufactured by Shimadzu Corporation-Micromeritics Corporation is used, for example. A nitrogen gas is adsorbed while changing a pressure, and an adsorption isotherm with a relative pressure on the horizontal axis and a N2 gas adsorption amount on the vertical axis is determined. Assuming that this curve follows BET theory, the BET equation is adopted, in which the specific surface area of an active material powder can be calculated.

[130] Next, an example of the electrode composite according to the first embodiment will be described with reference to the drawings.

[131] First, a first example of the electrode composite according to the first embodiment will be described with reference to Figures 1 and 2.

[132] Figure 1 is a schematic cross-sectional view of a first example of the electrode composite according to the first embodiment. Figure 2 is an enlarged cross-sectional view of a portion A of the electrode composite shown in Figure 1.

[133] An electrode composite 10 shown in Figures 1 and 2 has a negative electrode 3. The negative electrode 3 includes a belt-like negative electrode current collector 3a shown in Figure 1 and a layer containing negative electrode active material 3b supported by both surfaces of the negative electrode current collector 3a. Both end portions 3c of the negative electrode current collector 3a do not support the layer containing negative electrode active material 3b on any surfaces.

[134] As shown in Figure 2, the layer containing negative electrode active material 3b includes the secondary particles of negative electrode active material 3A. The average secondary particle size of negative electrode active material secondary particles is 1 μm to 30 μm. In Figure 2, secondary particles are schematically indicated by circles or ellipses. Although not shown in Figure 2, the layer containing negative electrode active material 3b additionally contains conductive agent particles and a binder.

[135] The electrode composite 10 shown in Figures 1 and 2 additionally includes two insulating particle layers 4. As shown in Figures 1 and 2, each of the insulating particle layers 4 has a first surface 4-1 and a second surface 4-2 opposite.

[136] As shown in Figure 1 and Figure 2, the first surface 4-1 of the insulating particle layer 4 is in contact with the layer containing negative electrode active material 3b. Thereby, the insulating particle layer 4 is provided in the layer containing negative electrode active material 3b.

[137] As shown in Figure 2, the first surface 4-1, which is an interface between the negative electrode active material-containing layer 3b and the insulating particle layer 4, includes plural indentations that are gaps between the secondary particles of 3A negative electrode active material. As shown in Figure 2, the insulating particle layer 4 fills the gaps.

[138] Furthermore, as shown in Figure 2, the second surface 4-2 of the insulating particle layer 4 does not so significantly reflect the irregularities on the first surface 41. Specifically, the surface roughness of the second surface 4-2 is 0. 1 μm or less.

[139] Next, a second example of the electrode composite according to the first embodiment will be described with reference to Figure 3.

[140] Figure 3 is a schematic cross-sectional view of a second example of the electrode composite according to the first embodiment.

[141] A composite electrode 10 shown in Figure 3 includes an electrode 8 that has a bipolar structure. The electrode 8 includes a belt-like current collector 8a. The current collector 8a has a third surface 8a-1 and an opposite fourth surface 8a-2.

[142] The electrode composite 10 shown in Figure 3 additionally includes a layer containing negative electrode active material 3b and a layer containing positive electrode active material 5b. The layer containing negative electrode active material 3b is provided on the third surface 8a-1 of the current collector 8a. The negative electrode active material-containing layer 3b has a similar structure to the electrode composite 10 of the first example described with reference to Figures 1 and 2. The positive electrode active material-containing layer 5b is provided on the fourth surface 8a-2 of current collector 8a. Both end portions 8c of the current collector 8a do not support the negative electrode active material-containing layer 3b nor the positive electrode active material-containing layer 5b on any surface.

[143] The electrode composite 10 shown in Figure 3 additionally includes an insulating particle layer 4 provided in the layer containing negative electrode active material 3b. The insulating particle layer 4 has a similar structure to the electrode composite 10 of the first example described with reference to Figures 1 and 2.

[144] According to the first embodiment described above, a composite electrode is provided. This electrode composite includes a layer containing negative electrode active material and an insulating particle layer. The layer containing negative electrode active material includes secondary particles of negative electrode active material. The average secondary particle size of negative electrode active material secondary particles is 1 μm to 30 μm. The insulating particle layer includes inorganic compound particles. The insulating particle layer is provided in the layer containing negative electrode active material. The insulating particle layer has a first surface and a second surface opposite the first surface. The first surface is in contact with the layer containing negative electrode active material. The surface roughness of the second surface of the insulating particle layer is 0.1 μm or less. When this electrode composite is used in a secondary battery, an electrical short circuit between the layer containing negative electrode active material and the positive electrode and side reactions of the negative electrode active material secondary particles with the electrolyte can be suppressed. As a result, the electrode composite according to the first embodiment can design a secondary battery that can exhibit excellent output performance.

(SECOND MODE)

[145] According to a second embodiment, a secondary battery is provided. The secondary battery includes the electrode composite according to the first embodiment, and a positive electrode. The positive electrode includes a layer that contains positive electrode active material. The second surface of the insulating particle layer of the electrode composite is in contact with the layer containing positive electrode active material.

[146] The positive electrode may additionally include a positive electrode current collector. The positive electrode current collector may have a flat shape similar to the belt having, for example, one surface and the other surface as an opposite surface thereof (a reverse surface relative to the first surface). The layer containing positive electrode active material may be provided on both surfaces of the positive electrode current collector, or may be provided on one of the surfaces. The positive electrode current collector may include a portion that does not support the layer containing positive electrode active material on any surface. This portion can serve as a positive electrode flap, for example.

[147] The electrode composite and the positive electrode can constitute an electrode group. The electrode group may have a battery-type structure or a winding-type structure. In a group of electrodes having a stack-type structure, the electrode composite (or composites) and the positive electrode (or electrodes) are stacked so that the positive electrode active material-containing layer and the active material-containing layer of negative electrodes face each other with the insulating particle layer sandwiched between them. A group of electrodes having a winding-type structure includes a coiled body obtained by winding a stack of a composite electrode and a positive electrode.

[148] A secondary battery of a variant according to a second embodiment includes electrodes that each have a bipolar structure, a first electrode composite that has a bipolar structure, and a second electrode composite that has a bipolar structure and located close to the first electrode composite. Each electrode that has the bipolar structure can have a structure similar to the electrode that has the bipolar structure described in the description of the first embodiment. Bipolar electrodes are stacked so that, for example, a second surface of an insulating particle layer of a first electrode composite is in contact with a layer containing positive electrode active material of a second electrode composite located next to the first composite. of electrode, so that a group of electrodes can be constituted.

[149] The secondary battery according to the second embodiment may include a non-aqueous electrolyte. That is, the secondary battery according to the second embodiment may be a non-aqueous electrolyte battery. When the inorganic compound particles are solid electrolyte particles, this solid electrolyte can also be used as a non-aqueous electrolyte. A non-aqueous electrolyte battery as an aspect of the secondary battery according to the second embodiment may include additional non-aqueous electrolyte.

[150] For example, the secondary battery according to the second embodiment may additionally include a non-aqueous gel electrolyte. The insulating particle layer may be impregnated with at least a portion of the non-aqueous gel electrolyte. In this way, the non-aqueous gel electrolyte can be held by the insulating particle layer. The non-aqueous gel electrolyte may be held by a layer containing negative electrode active material and/or a layer containing positive electrode active material.

[151] In the case of using an electrode group impregnated with a non-aqueous gel electrolyte in an insulating particle layer, which has a second surface with a surface roughness of more than 0.1 μm, in the secondary battery, an electrical short circuit occurs between the positive electrode and the negative electrode, so that the output performance deteriorates. On the other hand, when the secondary battery according to the second embodiment includes the electrode composite according to the first embodiment, excellent output performance can be exhibited even when a non-aqueous gel electrolyte is included. This point will be described in detail below.

[152] Titanium-based oxides (TiO2(B)) that have a monoclinic β-type structure and titanium-niobium composite oxides such as Nb2TiO7 were studied, with titanium-based oxides and titanium-niobium composite oxides being studied. niobium have a greater theoretical capacity per unit weight than that of the spinel-type lithium titanate described above. However, a secondary battery produced that uses the same as negative electrode active materials has a problem of a low energy density for a lithium secondary battery that uses a graphite-based negative electrode.

[153] Furthermore, in the case of a secondary battery that uses a liquid electrolyte, a liquid electrolyte obtained by dissolving a charge carrier supporting electrolyte in a solvent is used, in addition to a battery that uses a composite oxide of titanium or a niobium oxide composite as a negative electrode. In a battery in which electrode assemblies and a liquid electrolyte are housed in a single container, and the electrode assemblies are electrically connected in series and each of the assemblies includes a positive electrode and a negative electrode, an ion short circuit occurs between the electrode assemblies through the liquid electrolyte. Therefore, the battery cannot function as a secondary battery.

[154] By using, for example, a non-aqueous gel electrolyte in place of the liquid electrolyte, the ion short circuit between the electrode assemblies can be suppressed. However, a problem was found that it is difficult to uniformly insert the non-aqueous gel electrolyte between the positive electrode and the negative electrode. For example, it has been found that a resistance value increases in a portion where a large amount of the non-aqueous gel electrolyte is present between the electrodes, and output/input characteristics of the entire secondary battery deteriorate. On the other hand, it was found that in a portion where the non-aqueous gel electrolyte content is low, the insulating property between the positive electrode and the negative electrode is less likely to be guaranteed, and it was found that short circuit Electricity tends to occur between the positive electrode and the negative electrode. If an electrical short circuit occurs, there is a problem that the battery does not function as a secondary battery.

[155] On the other hand, as described above, the surface roughness of the insulating particle layer of the electrode composite according to the first embodiment is 0.1 μm or less, and therefore the insulating particle layer may have a thickness more uniform. Such an insulating particle layer can retain the non-aqueous gel electrolyte more evenly and can sufficiently guarantee the insulating property between the positive electrode and the negative electrode. Thereby, the secondary battery according to the second embodiment can exhibit excellent output performance.

[156] Particularly, in the electrode composite of a preferred aspect, which includes inorganic compound particles having an average secondary particle size of 15 μm to 30 μm in an insulating particle layer, the insulating particle layer may have a space in which a non-aqueous gel electrolyte can be sufficiently maintained.

[157] The secondary battery according to the aspect in which the insulating particle layer includes the solid electrolyte layer described above may not include an additional electrolyte.

[158] The secondary battery may additionally include a container member, a positive electrode terminal, and a negative electrode terminal.

[159] The container member can accommodate a group of electrodes. The positive electrode terminal can be electrically connected to the positive electrode. The negative electrode terminal can be electrically connected to the negative electrode.

[160] Hereinafter, the positive electrode, the negative electrode, the non-aqueous gel electrolyte, the container member, the positive electrode terminal and the negative electrode terminal will be described in detail.

(A) POSITIVE ELECTRODE

[161] The positive electrode current collector is preferably aluminum foil, or aluminum alloy foil containing at least one element selected from Mg, Ti, Zn, Mn, Fe, Cu, and Si. The particle size average crystal size of aluminum foil and aluminum alloy foil is preferably 50 μm or less. The average crystal particle size is more preferably 30 μm or less, and most preferably 5 μm or less. The average crystal particle size of 50μm or less can drastically increase the strength of aluminum foil or aluminum alloy foil. This results in allowing the positive electrode to increase in density at high pressing pressure, and thereby allowing the capacity of the battery to be increased.

[162] The average crystal particle size can be measured according to the method described above.

[163] The average crystal particle sizes of aluminum foil and aluminum alloy foil are affected in a complex manner by many factors such as material structure, impurities, processing conditions, heat treatment hysterisis and annealing conditions. The crystal particle size can be adjusted by combining the previously mentioned factors in the current collector manufacturing process.

[164] Aluminum foil and aluminum alloy foil are, for example, 20 μm or less, more preferably 15 μm thick. The aluminum foil preferably has a purity of 99% by mass or more. An alloy that contains an element such as magnesium, zinc, and silicon is preferred such as aluminum alloy. On the other hand, the content of a transition metal such as iron, copper, nickel, and chromium is preferably 1% by mass or less.

[165] As materials of the positive electrode active material, the conductive agent and binder that can be included in the layer containing positive electrode active material, materials that can be included in the layer containing positive electrode active material described in the section of first modality can be used.

(B) NEGATIVE ELECTRODE

[166] As negative electrode materials, the same materials as the negative electrode materials described in the first embodiment section can be used.

(C) NON-AQUEOUS GEL ELECTROLYTE

[167] A gel electrolyte includes a gel substance and an electrolyte dissolved in the gel substance. Since gel electrolyte has low fluidity, gel electrolyte can be kept between a positive electrode and a negative electrode in a secondary battery without leakage.

[168] The gel electrolyte can be prepared by the following procedure, for example. First, a liquid nonaqueous electrolyte is prepared by dissolving an electrolyte in a nonaqueous solvent. Then, a postpolymer with the ability to form a gel electrolyte is added to this liquid non-aqueous electrolyte. Then, by heating a mixture obtained, a non-aqueous gel electrolyte is obtained.

[169] As the electrolyte, lithium salts such as lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium hexafluoroantimonate (LiSbF6), can be used. lithium trifluoromethane sulfonate (LiCF3SO3), lithium bistrifluoromethylsulfonylimide (LiN(CF3SO2)2), lithium bis(pentafluoroethanesulfonyl)imide (Li(C2F5SO2)2N), lithium bis(oxalate)borate(LiB(C2O4)2), and lithium difluoro (trifluoro-2-oxide-2-trifluoro-methylpropionate(2-)-0.0) borate (LiBF2(OCOOC(CF3)2). As the electrolyte, one of the above compounds can be used by itself , or a mixture of two or more of them can be used.It is preferred that the electrolyte is oxidized even at a high potential, and LiBF4 or LiPF6 is more preferred.

[170] The electrolyte salt concentration is preferably 1 M to 3 M. This makes the viscosity of the non-aqueous electrolyte moderate and can achieve excellent performance even when a high load current flows.

[171] Examples of non-aqueous solvents include cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), dipropyl carbonate (DPC) and vinylene carbonate, chain carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate (MEC), cyclic ethers such as tetrahydrofuran (THF), 2-methyl tetrahydrofuran (2MeTHF) and dioxolane (DOX), chain ethers such as dimethoxyethane (DME) and diethoethane ( DEE), γ-butyrolactone (GBL), acetonitrile (AN), and sulfolane (SL). As a non-aqueous solvent, one of these solvents can be used alone, or a mixed solvent in which two or more solvents are mixed can be used.

[172] Non-aqueous electrolyte may contain additives. The additive is not particularly limited, but examples thereof include vinylene acetate (VA), vinylene butyrate, vinylene hexanate, vinylene crotonate, and catechol carbonate. The concentration of the additive is preferably 0.1 mass % to 3 mass % relative to the mass of the non-aqueous electrolyte before adding the additive. A more preferred range is 0.5% by mass to 1% by mass.

[173] As a suitable postpolymer for gel electrolyte formation, for example, polyvinylidene fluoride, a vinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, polyethylene oxide, polypropylene oxide, an oxide copolymer can be used. of ethylene and propylene oxide, and a cross-linked polymer that contains an ethylene oxide chain as a backbone or a side chain. Like the postpolymer, one of these may be used by itself, or a mixture of two or more of them may be used.

[174] The postpolymer can be mixed with the liquid non-aqueous electrolyte such that a volume ratio of the postpolymer: liquid non-aqueous electrolyte is 1:1 to 4:1, for example.

[175] For example, the liquid non-aqueous electrolyte containing the postpolymer is impregnated into a group of electrodes that includes the electrode composite according to the first embodiment and this group of electrodes is subjected to heat treatment at a temperature of 40 °C to 80 °C in an inert atmosphere, and in this way a non-aqueous gel electrolyte impregnated in the electrode group can be obtained. The non-aqueous gel electrolyte prepared in this way is impregnated into the negative electrode active material-containing layer, the positive electrode active material-containing layer and the insulating particle layer, respectively.

(D) RECIPIENT MEMBER

[176] For example, a laminate film of 0.2 mm or less in wall thickness or a metal container of 1.0 mm or less in wall thickness can be used as the container member. The metal container is preferably 0.5 mm or less in wall thickness.

[177] The shape of the container member may be a flat shape, a square shape, a cylindrical shape, a coin shape, a button shape, a blade shape, or a stacked shape, depending on the intended use of the secondary battery. in accordance with this modality. The intended use of the secondary battery according to the present embodiment may be, for example, a small-sized battery installed in a portable electronic device or the like, or a large-sized battery installed in a vehicle such as a two-wheeled automobile. four wheels.

[178] Laminate film is a multilayer film that includes a metal layer and a resin layer that coats the metal layer. For weight reduction, the metal layer is preferably aluminum foil or aluminum alloy foil. The resin layer intended to reinforce the metal layer may use polymers such as polypropylene (PP), polyethylene (PE), nylon, and polyethylene terephthalate (PET). The laminate film can be formed into the shape of the container member through thermal fusion bond sealing.

[179] For example, aluminum or an aluminum alloy can be used for the metal container. The aluminum alloy is preferably an alloy that contains an element such as magnesium, zinc, and silicon. On the other hand, the content of transition metals such as iron, copper, nickel, and chromium is preferably 1% by weight or less. In this way, it becomes possible to improve long-term reliability and radiation performance drastically under a high temperature environment.

[180] The aluminum metal container or an aluminum foil, for example, a metal can is preferably 50 μm or less in average crystal particle size. The average crystal particle size is most preferably 30 μm or less. The average crystal particle size is further preferably 5 μm or less. The average crystal particle size adjusted to 50 μm or less can drastically increase the strength of aluminum metal can or aluminum alloy. Additionally, the size may additionally cause the can to be thin-walled. As a result, a battery suitable for an in-vehicle application can be provided that is light in weight, high output, and excellent in long-term reliability.

(E) NEGATIVE ELECTRODE TERMINAL

[181] The negative electrode terminal may be formed from, for example, a material that is electrically stable at a potential within the range of 0.4 V (vs Li/Li+) to 3 V (vs Li/Li+) relative to to the redox potential of lithium, and has electrical conductivity. Specifically, examples of the material include an aluminum alloy that contains an element such as Mg, Ti, Zn, Mn, Fe, Cu, and Si, and aluminum. The same material as the negative electrode current collector is preferred in order to reduce contact resistance.

(F) POSITIVE ELECTRODE TERMINAL

[182] The positive electrode terminal may be formed from a material that is electrically stable at a potential within the range of 3 V (vs Li/Li+) to 5 V (vs Li/Li+) relative to the redox potential of lithium, and has electrical conductivity. Specifically, examples of the material include an aluminum alloy that contains an element such as Mg, Ti, Zn, Mn, Fe, Cu, and Si, and aluminum. The same material as the positive electrode current collector is preferred so as to reduce contact resistance.

[183] Next, several examples of the secondary battery according to the second embodiment will be described with reference to the drawings.

[184] First, a first example of a secondary battery will be described with reference to Figures 4 and 5.

[185] Figure 4 is a schematic cross-sectional view of a first example of a secondary battery according to the second embodiment. Figure 5 is an enlarged cross-sectional view of a portion B of the secondary battery shown in Figure 4.

[186] The secondary battery 100 shown in Figures 4 and 5 includes a bag-like container member 2 shown in Figure 4, an electrode group 1 shown in Figures 4 and 5, and a non-aqueous gel electrolyte (not shown) . That is, the secondary battery 100 shown in Figures 4 and 5 is a non-aqueous electrolyte battery. The electrode group 1 and the non-aqueous gel electrolyte are housed in the container member 2. The non-aqueous gel electrolyte (not shown) is held by the electrode group 1.

[187] The pouch-like container member 2 is made of a laminate film that includes two resin layers and a metal layer sandwiched therebetween.

[188] As shown in Figure 4, electrode group 1 is a group of flat coiled electrodes. As shown in Figure 5, the flat-wound electrode group 1 includes a negative electrode 3, an insulating particle layer 4, and a positive electrode 5. The insulating particle layer 4 is sandwiched between the negative electrode 3 and the positive electrode 5 .

[189] The negative electrode 3 includes a negative electrode current collector 3a and a layer containing negative electrode active material 3b. As shown in Figure 5, in a portion of the negative electrode 3 located in the outermost layer of the coiled electrode group 1, the layer containing negative electrode active material 3b is formed only on the inner surface side of the negative electrode current collector 3a. The other portion on the negative electrode 3 includes the layer containing negative electrode active material 3b formed on each of both surfaces of the negative electrode current collector 3a.

[190] The positive electrode 5 includes a positive electrode current collector 5a and a layer containing positive electrode active material 5b formed on each of both surfaces of the positive electrode current collector 5a.

[191] The insulating particle layer 4 has the same structure as that of the insulating particle layer 4 shown in Figure 2. That is, the insulating particle layer 4 has a first surface 4-1 and an opposite second surface 4-2 . The first surface 4-1 of the insulating particle layer 4 is in contact with the layer containing negative electrode active material 3b. The second surface 4-2 of the insulating particle layer 4 is in contact with the layer containing positive electrode active material 5b.

[192] As shown in Figure 4, a negative electrode terminal 6 and a positive electrode terminal 7 are located in the vicinity of the outer peripheral end of the wound electrode group 1. The negative electrode terminal 6 is connected to a part of the collector of negative electrode current 3a from the negative electrode 3 located in the outermost layer. The positive electrode terminal 7 is connected to the positive electrode current collector 5a of the positive electrode 5 located in the outermost layer. The negative electrode terminal 6 and the positive electrode terminal 7 extend to the outer side of an opening portion of the bag-like container member 2. The bag-like container member 2 is heat sealed with a layer of thermoplastic resin. provided on its inner surface.

[193] Next, a second example of a secondary battery will be described with reference to Figures 6 and 7.

[194] Figure 6 is a partial sectional perspective view schematically showing a second example of a secondary battery in accordance with the second embodiment. Figure 7 is a schematic cross-sectional view of an assembly of a positive electrode and a negative electrode included in the secondary battery shown in Figure 6.

[195] A secondary battery 100 shown in Figures 6 and 7 includes an electrode group 11 shown in Figure 6, a container member 12 shown in Figure 6, and a non-aqueous gel electrolyte (not shown). That is, the secondary battery 100 shown in Figures 6 and 7 is a non-aqueous electrolyte battery. The electrode group 11 and the non-aqueous gel electrolyte are housed in the container member 12. The non-aqueous electrolyte is held in the electrode group 11.

[196] The container member 12 is made of a laminate film that includes two resin layers and a metal layer sandwiched between the resin layers.

[197] Figure 7 shows an assembly of an electrode assembly 11' included in the electrode group 11. The electrode group 11 shown in Figure 6 includes assemblies of the electrode assemblies 11'.

[198] As shown in Figure 7, the electrode assembly 11' includes a negative electrode 3 and a positive electrode 5. As shown in Figure 7, the negative electrode 3 includes a negative electrode current collector 3a and a layer containing negative electrode active material 3b supported on each of both surfaces of the negative current collector 3a. A part 3c of the negative electrode current collector 3a of the negative electrode 3 projects on one side of the negative electrode 3. The projected part 3c of the negative electrode current collector 3a is electrically connected to a strip-shaped negative electrode terminal 16 shown in Figure 6. The positive electrode 5 includes a positive electrode current collector 5a and a layer containing positive electrode active material 5b supported on each of both surfaces of the positive current collector 5a. A part 5c of the positive electrode current collector 5a of the positive electrode 5, located on the opposite side to the projected part 3c of the negative electrode current collector 3a, projects from the positive electrode 5. The projected part 5c of the electrode current collector positive electrode 5a is electrically connected to a strip-shaped positive electrode terminal 17 shown in Figure 6.

[199] As shown in Figure 7, the electrode assembly 11' additionally includes an insulating particle layer 4. The insulating particle layer 4 has the same structure as that of the insulating particle layer 4 shown in Figure 2. The first surface 4-1 of the insulating particle layer 4 is in contact with the negative electrode active material-containing layer 3b. The second surface 4-2 of the insulating particle layer 4 is in contact with the layer containing positive electrode active material 5b.

[200] Electrode assemblies 11' that each have the same structure as that of the electrode assembly 11' shown in Figure 7 are stacked to constitute the electrode group 11 shown in Figure 6. In the electrode group 11, the second surface 4-2 of the insulating particle layer 4 of one electrode assembly 11' is in contact with the positive electrode active material-containing layer 5b of another electrode assembly 11'. In the electrode group 11, parts 3c of the negative electrode current collectors 3a of the electrode assemblies 11' project from the negative electrodes 3 in the same direction, and parts 5c of the positive electrode current collectors 5a of the electrode assemblies 11' project from the positive electrodes 5 in the same direction.

[201] The tip of the strip-shaped positive electrode terminal 17 is opposite the negative electrode terminal 16. The tip of each of the positive electrode terminal 17 and the negative electrode terminal 16 are extended outside the container member 12.

[202] A group of electrodes that can be included in a secondary battery according to the second embodiment is not limited to those shown in Figures 4 to 7,

[203] Figure 8 is a schematic cross-sectional view of an example of an electrode group that can be included in a secondary battery according to the second embodiment.

[204] The electrode group 11 shown in Figure 8 includes two composite electrodes 10 and two positive electrodes 5

[205] Each electrode composite 10 includes a negative electrode 3. The negative electrode 3 includes a strip-shaped negative electrode current collector 3a and a layer containing negative electrode active material 3b supported on each of both surfaces of the negative current collector 3a. The negative electrode current collector 3a includes a portion 3c that does not support the negative electrode active material-containing layer 3b on the surface thereof at one end.

[206] An electrode composite 10 additionally includes two insulating particle layers 4. The other electrode composite 10 additionally includes an insulating particle layer 4. These insulating particle layers 4 have the same structure as that of the insulating particle layer 4 shown in Figure 2.

[207] Each positive electrode 5 includes a strip-shaped positive electrode current collector 5a and a layer containing positive electrode active material 5b supported on each of both surfaces of the positive current collector 5a. The positive electrode current collector 5a includes a portion 5c that does not support the positive electrode active material-containing layer 5b on the surface thereof at one end.

[208] Each positive electrode 5 is provided in the insulating particle layer 4 of each electrode composite 10. A layer containing positive electrode active material 5b of each positive electrode 5 is in contact with the second surface 42 of the insulating particle layer 4.

[209] Furthermore, as shown in Figure 8, the part 3c of the negative electrode current collector 3a of an electrode composite 10 is electrically connected to the part 5c of the positive electrode current collector 5a of a positive electrode 5 through a cable 9. The two electrode composites 10 and the two electrically connected positive electrodes thus constitute the electrode group 11.

[210] Next, an example of a group of electrodes that includes electrodes that each have a bipolar structure will be described with reference to Figure 9.

[211] Figure 9 is a schematic cross-sectional view of another example of an electrode group that can be included in a secondary battery according to the second embodiment.

[212] The electrode group 11 shown in Figure 9 includes four electrode composites 10A, 10B, 10C and 10D, and a positive electrode 5.

[213] Each of the electrode composites 10A, 10B, and 10C has the same structure as that of the electrode composite 10 described with reference to Figure 3. That is, the electrode composite 10A includes an electrode 81 that has a bipolar structure and an insulating particle layer 4 provided in a layer containing negative electrode active material 3b of the electrode 81. The electrode composite 10B includes an electrode 82 having a bipolar structure and an insulating particle layer 4 provided in a layer containing negative electrode active material 3b of electrode 82. The electrode composite 10C includes an electrode 83 that has a bipolar structure and an insulating particle layer 4 provided in a layer that contains negative electrode active material 3b of electrode 83.

[214] The 10D electrode composite includes a strip-shaped negative electrode current collector 3a, a layer containing negative electrode active material 3b supported on a surface of the negative electrode current collector 3a, and a particle layer insulator 4 provided in the layer containing negative electrode active material 3b. An end 3c of the negative electrode current collector 3a does not support the layer containing negative electrode active material 3b on the surface thereof.

[215] The positive electrode 5 includes a strip-shaped positive electrode current collector 5a and a layer containing positive electrode active material 5b supported on a surface of the positive electrode current collector 5a. An end 5c of the positive electrode current collector 5a does not support the layer containing positive electrode active material 5b on the surface thereof.

[216] As shown in Figure 9, the positive electrode 5, the electrode composite 10A, the electrode composite 10B, the electrode composite 10C, and the electrode composite 10D are stacked in this order to constitute the electrode group 11.

[217] The insulating particle layer 4 included in each of the electrode composites 10A to 10D has the same structure as that of the insulating particle layer 4 shown in Figure 2. The layer containing positive electrode active material 5b of the electrode positive 5 is in contact with the second surface 42 of the insulating particle layer 4 of the electrode composite 10A. The positive electrode active material-containing layer 5b of the electrode composite 10A is in contact with the second surface 4-2 of the insulating particle layer 4 of the electrode composite 10B. The positive electrode active material-containing layer 5b of the electrode composite 10B is in contact with the second surface 4-2 of the insulating particle layer 4 of the electrode composite 10C. The positive electrode active material-containing layer 5b of the electrode composite 10C is in contact with the second surface 4-2 of the insulating particle layer 4 of the electrode composite 10D.

[218] The secondary battery according to the second embodiment includes the electrode composite according to the first embodiment. Therefore, the secondary battery can exhibit excellent output performance.

(THIRD MODE)

[219] According to a third embodiment, a battery module is provided. The battery module according to the third embodiment includes secondary batteries each according to the second embodiment.

[220] In the battery module according to the third embodiment, each of the single batteries can be electrically connected and arranged in series, in parallel, or in a combination of series connection and parallel connection.

[221] Next, an example of a battery module according to the third embodiment will be described with reference to the drawings.

[222] Figure 10 is a perspective view schematically showing an example of a battery module according to the third embodiment. A battery module 200 shown in Figure 10 includes five single batteries 100, four bus bars 21, a positive electrode side cable 22, and a negative electrode side cable 23. Each of the five single batteries 100 is a secondary battery of according to the second modality.

[223] Each busbar 21 connects a negative electrode terminal 6 of a single battery 100 and a positive electrode terminal 7 of a neighboring single battery 100. The five single batteries 100 are thereby connected in series via the four bus bars 21. That is, the battery module 200 shown in Figure 10 is a series connection battery module.

[224] As shown in Figure 10, the positive electrode terminal 7 of the single battery 100 located at the left end of the five single batteries 100 is connected to the positive electrode side cable 22 for external connection. Additionally, the negative electrode terminal 6 of the single battery 100 located at the right end of the five single batteries 100 is connected to the negative electrode side cable 23 for external connection.

[225] The battery module according to the third embodiment includes the secondary battery according to the second embodiment. Therefore, the battery module according to the third embodiment can exhibit excellent output performance.

(FOURTH MODE)

[226] According to a fourth embodiment, a battery pack is provided. The battery pack includes the battery module according to the third embodiment. The battery pack may include a single secondary battery according to the second embodiment instead of the battery module according to the third embodiment.

[227] The battery pack according to the fourth embodiment may additionally include a protective circuit. The protective circuit has a function to control the charging and discharging of the secondary battery. Alternatively, a circuit included in equipment (e.g., electronic devices, vehicles, and the like) in which the battery pack serves as a power source can be used as the protective circuit for the battery pack.

[228] Furthermore, the battery pack may additionally include an external power distribution terminal. The external power distribution terminal is configured to output current externally from the secondary battery, and to admit current external to the secondary battery. In other words, when the battery pack is used as a power source, current is externally supplied through external power distribution. Furthermore, when the battery pack is charged, charging current (including regenerative energy from the motive force of vehicles such as automobiles) is supplied to the battery pack through the external power distribution terminal.

[229] Next, a battery pack as an example in accordance with the fourth embodiment will be described with reference to the drawings.

[230] Figure 11 is an exploded perspective view showing an example of a battery pack according to the fourth embodiment. Figure 12 is a block diagram showing an electrical circuit of the battery pack in Figure 11.

[231] A battery pack 300 shown in Figures 11 and 12 includes a housing container 31, a cover 32, protective blades 33, a battery module 200, a printed wiring board 34, a wiring harness 35, an insulating plate ( not shown).

[232] The housing container 31 is configured to be capable of housing the protective blades 33, the battery module 200, the printed wiring board 34, and the wiring 35. The lid 32 is placed on the housing container 31 to house the battery module 200 and the like. Each of the housing container 31 and the lid 32 is provided with an opening, a connection terminal or the like (not shown) that is to be connected to an external device or the like.

[233] Protective foils 33 are disposed on both inner surfaces in a long lateral direction of the housing container 31 and on an inner surface facing the printed wiring board 34 via the battery module 200 in a short lateral direction of the housing container 31. The protective blades 33 are made of, for example, rubber or resin.

[234] The battery module 200 includes single batteries 100, a positive electrode side cable 22, a negative electrode side cable 23, and an adhesive tape 24. The battery module 200 may be a single battery 100.

[235] Each of the single batteries 100 has the structure shown in Figures 4 and 5. At least one of the single batteries 100 is a secondary battery according to the second embodiment. The single batteries 21 are stacked so that the negative electrode terminals 6 and the outwardly extending positive electrode terminals 7 are arranged in the same direction. The single batteries 100 are electrically connected in series as shown in Figure 12. The single batteries 100 may be connected in parallel, or in a combination of series connection and parallel connection. If the plural single batteries 100 are connected in parallel, the capacity of the battery increases as compared to a case in which they are connected in series.

[236] Adhesive tape 24 secures the single batteries 100. In place of the adhesive tape 24, heat shrink tape can be used to secure the single batteries 100. In this case, protective sheets are provided on both sides of the battery module 200, A heat-shrinkable tape is wrapped around the battery module, and the heat-shrinkable tape is heat-shrinkable to join the single batteries together.

[237] One end of the positive electrode side cable 22 is connected to the positive electrode terminal 7 of the single battery 100 located in the bottom layer of the stack of the single batteries 100. One end of the negative electrode side cable 23 is connected to the negative electrode 6 of the single battery 100 located on the top layer of the stack of the single batteries 100.

[238] A printed wiring board 34 is provided with a positive electrode side connector 341, a negative electrode side connector 342, a thermistor 343, a protective circuit 344, wires 345 and 346, an external power distribution terminal 347 , a positive-side wire 348a and a negative-side wire 348b. A main surface of the printed wiring board 34 faces the side plane of the battery module 200 into which the negative electrode terminals 6 and the positive electrode terminals 7 are extended. The insulating plate (not shown) is provided between the printed wiring board 34 and the battery module 200.

[239] The positive electrode side connector 341 is provided with a through hole. The other end of the positive electrode side cable 22 is inserted from the through hole so as to electrically connect the positive electrode side connector 341 to the positive electrode side cable 22. The negative electrode side connector 342 is provided with a through hole. The other end of the negative electrode side cable 23 is inserted into the through hole in order to electrically connect the negative electrode side connector 342 to the negative electrode side cable 23.

[240] Thermistor 343 is fixed to a main surface of the printed wiring board 34. Thermistor 343 detects the temperature of each single battery 100 and transmits the detection signal to the protective circuit 344.

[241] The external power distribution terminal 347 is fixed to the other main surface of the printed wiring board 34. The external power distribution terminal 347 is electrically connected to a device protruding outside the battery pack 300.

[242] The protective circuit 344 is fixed to the other main surface of the printed wiring board 34. The protective circuit 344 is connected to the external power distribution terminal 347 via the positive side wire 348a. The protective circuit 344 is connected to the external power distribution terminal 347 via the negative side wire 348b. Additionally, the protective circuit 344 is electrically connected to the positive electrode side connector 341 via wire 345. The protective circuit 344 is electrically connected to the negative electrode side connector 342 via wire 346. Furthermore, the protective circuit 344 is electrically connected to each of the 100 single batteries via wire 35.

[243] The protective circuit 344 controls the charging and discharging of the single plural batteries 100. The protective circuit 344 is also configured to sever the electrical connection between the protective circuit 344 and the external power distribution terminal 347 to an external device, with based on detection signals transmitted from thermistor 343 or detection signals transmitted from each single battery 100 or battery module 200.

[244] An example of the detection signal transmitted from the thermistor 343 is a signal representing that the temperature of the single battery 100 is detected to be a predetermined temperature or higher. An example of the detection signal transmitted from each single battery 100 or battery module 200 is a signal representing the detection of overcharge, overdischarge, and overcurrent of the single battery 100. If overload or the like is detected for each of the single batteries 100, the battery voltage can be detected, or a positive electrode potential or negative electrode potential can be detected. In the latter case, a lithium electrode to be used as a reference pole is inserted into each single battery 100.

[245] Note that, like the protective circuit 344, a circuit included in a device (e.g., an electronic device or an automobile) that uses the battery pack 300 as a power source can be used.

[246] Such a battery pack 300 is used in, for example, an application in which the battery pack 300 is required to have excellent cycling performance when a large current is output. More specifically, the battery pack 300 is used as, for example, a power source for an electronic device, a stationary battery, or an on-board battery for a vehicle or a railway vehicle. As the electronic device, for example, a digital camera can be used. Battery pack 300 is particularly and preferably used as an onboard battery.

[247] As described above, the battery pack 300 includes the external power distribution terminal 347. Therefore, the battery pack 300 can output a current from the battery module 200 to an external device and admit a current from the external device to the battery module 200 through the external power distribution terminal 347. In other words, when using the battery pack 300 as a power source, current from the battery module 200 is supplied to the external device through the distribution terminal external power supply 347. When charging the battery pack 300, a charge current from the external device is supplied to the battery pack 300 through the external power distribution terminal 347. If the battery pack 300 is used as a battery pack 347. board, the regenerative energy of a vehicle's driving force can be used as the charging current of the external device.

[248] Note that the battery pack 300 may include battery modules 200. In this case, the battery modules 200 may be connected in series, in parallel, or in a combination of series connection and parallel connection. The printed wiring board 34 and wire 35 can be omitted. In this case, the positive electrode side cable 22 and the negative electrode side cable 23 can be used as the external power distribution terminal.

[249] The battery pack according to the fourth embodiment includes the secondary battery according to the second embodiment or the battery module according to the third embodiment. Therefore, the battery pack according to the fourth embodiment can exhibit excellent output performance.

(FIFTH MODE)

[250] According to a fifth embodiment, a vehicle is provided. The battery pack according to the fourth embodiment is installed in that vehicle.

[251] In the vehicle according to the fifth embodiment, the battery pack is configured, for example, to recover regenerative energy from a driving force of the vehicle.

[252] Examples of the vehicle according to the fifth embodiment include two- to four-wheel hybrid electric automobiles, two- to four-wheel electric automobiles, electric assistance bicycles, and railway cars.

[253] In the vehicle according to the fifth embodiment, the installation position of the battery pack is not particularly limited. For example, in the case where the battery pack is installed in an automobile, the battery pack may be installed in the engine compartment of the vehicle, in the rear parts of the vehicle, or under the seats.

[254] An example of the vehicle according to the fifth embodiment is explained below, with reference to the drawings.

[255] Figure 13 is a schematic sectional view showing an example of a vehicle according to the fifth embodiment.

[256] A vehicle 400 shown in Figure 13 includes a vehicle body 40 and a battery pack 300 in accordance with the fourth embodiment.

[257] Vehicle 400 shown in Figure 13 is a four-wheeled automobile. As vehicle 400, for example, two- to four-wheel hybrid electric automobiles, two- to four-wheel electric automobiles, electric assistance bicycles, and railway cars can be used.

[258] Such vehicle 400 may have plural battery packs 300 installed. In such a case, the battery packs 300 may be connected in series, connected in parallel, or connected in a combination of series connection and parallel connection.

[259] The battery pack 300 is installed in an engine compartment located at the front of the vehicle body 40. The installation location of the battery pack 300 is not particularly limited. The battery pack 300 may be installed in the rear sections of the vehicle body 40, or under a seat. The battery pack 300 can be used as a power source of the vehicle 400. The battery pack 300 can also recover regenerative energy from the motive force of the vehicle 400.

[260] Next, with reference to Figure 14, an aspect of the vehicle according to the fifth embodiment is explained.

[261] Figure 14 shows another example of a vehicle according to the fifth embodiment. A vehicle 400, shown in Figure 14, is an electric automobile.

[262] Vehicle 400, shown in Figure 14, includes a vehicle body 40, a vehicle power source 41, a vehicle ECU (electrical control unit) 42, which is a master controller of the vehicle power source 41, an external terminal (an external power connection terminal) 43, an inverter 44, and a drive motor 45.

[263] Vehicle 400 includes vehicle power source 41, for example, in the engine compartment, in the rear sections of the automobile body, or under a seat. In Figure 14, the position of the vehicle power source 41 installed in the vehicle 400 is schematically shown.

[264] Vehicle power source 41 includes plural (e.g., three) battery packs 300a, 300b, and 300c, a battery management unit (BMU) 411, and a communication bus 412.

[265] The three battery packs 300a, 300b and 300c are electrically connected in series. The 300a battery pack includes a 200a battery module and a 301a battery module monitoring unit (VTM: voltage temperature monitoring). The 300b battery pack includes a 200b battery module, and a 301b battery module monitoring unit. The 300c battery pack includes a 200c battery module, and a 301c battery module monitoring unit. Battery packs 300a, 300b and 300c can each be independently removed, and can be exchanged for a different battery pack 300.

[266] Each of battery modules 200a to 200c includes plural single batteries connected in series. At least one of the plural single batteries is the secondary battery according to the second embodiment. Battery modules 200a to 200c each perform charging and discharging via a positive electrode terminal 413 and a negative electrode terminal 414.

[267] In order to collect information related to the safety of the vehicle power source 41, the battery management unit 411 communicates with the battery module that monitors the units 301a to 301c and collects information such as battery voltages or temperatures. only 100 included in the 200a to 200c battery modules included in the vehicle power source 41.

[268] Communication bus 412 is connected between battery management unit 411 and battery module monitoring units 301a to 301c. The communication bus 412 is configured such that multiple nodes (i.e., the battery management unit and one or more battery module monitoring units) share a set of communication lines. Communication bus 412 is, for example, a communication bus configured based on the CAN (Control Area Network) standard.

[269] Battery module monitoring units 301a to 301c measure a voltage and a temperature of each single battery in battery modules 200a to 200c based on commands from the battery management unit 411. It is possible, however, to measure temperatures only at multiple points per battery module, and temperatures of all single batteries do not need to be measured.

[270] The vehicle power source 41 may also have an electromagnetic contactor (e.g., a switching unit 415 shown in Figure 14) for switching connection between the positive electrode terminal 413 and the negative electrode terminal 414. switching unit 415 includes a precharge switch (not shown), which is turned on when battery modules 200a to 200c are charged, and a main switch (not shown), which is turned on when battery output is supplied to a load. The precharge switch and main switch include a relay circuit (not shown), which is switched on and off based on a signal supplied to a coil disposed near the switching elements.

[271] Inverter 44 converts an admitted direct current voltage to a high three-phase alternating current (AC) voltage to drive a motor. The three-phase output terminal (or terminals) of the inverter 44 is (are) connected to each three-phase input terminal of the drive motor 45. The inverter 44 controls an output voltage based on control signals from the battery management unit 411 or vehicle ECU 41, which controls the entire operation of the vehicle.

[272] The drive motor 45 is rotated by electrical power supplied from the inverter 44. Rotation is transferred to a drive shaft and wheels W by means of a differential gear unit, for example.

[273] Vehicle 400 also includes a regenerative braking mechanism, although not shown. The regenerative braking mechanism rotates the drive motor 45 when the vehicle 400 is braked, and converts kinetic energy into regenerative energy, such as electrical energy. The regenerative energy, recovered in the regenerative braking mechanism, is admitted to inverter 44 and converted into direct current. Direct current is admitted to the vehicle power source 41.

[274] One terminal of an L1 connection line is connected via a current detector (not shown) in the battery management unit 411 to the negative electrode terminal 414 of the vehicle power source 41. The other terminal of the line connection terminal L1 is connected to a negative electrode input terminal of the inverter 44.

[275] One terminal of a connecting line L2 is connected via the switching unit 415 to the positive electrode terminal 413 of the vehicle power source 41. The other terminal of the connecting line L2 is connected to a power input terminal positive electrode of inverter 44.

[276] The external terminal 43 is connected to the battery management unit 411. The external terminal 43 is capable of connecting, for example, to an external power source.

[277] The vehicle ECU 42 cooperatively controls the battery management unit 411 together with other units in response to inputs operated by a trigger or the like, thereby realizing management of the entire vehicle. Safety-related data of the vehicle power source 41, such as a remaining capacity of the vehicle power source 41, is transferred between the battery management unit 411 and the vehicle ECU 42 via communication lines.

[278] The vehicle according to the fifth embodiment includes the battery pack according to the fourth embodiment. Therefore, the vehicle can exhibit excellent output performance.

[EXAMPLES]

[279] Examples will be described below, but embodiments are not limited to the examples described below.

(EXAMPLE 1)

[280] In Example 1, an electrode composite of Example 1 was produced by the following procedure.

<NEGATIVE ELECTRODE PRODUCTION>

[281] As an active material, an Nb2TiO7 powder was provided that has an average secondary particle size of 10 μm and that has a lithium insertion and extraction potential greater than 1.0 V relative to the redox potential of lithium . This material, acetylene black which has an average particle size of 35 nm as a conductive agent, methyl carboxyl cellulose as a binder and styrene butadiene rubber as a binder were mixed in a mass ratio of 93:5:1: 1 while adding pure water, thereby preparing an aqueous paste. The obtained aqueous paste was coated on both surfaces of an aluminum foil having a thickness of 15 μm and an average crystal grain size of 30 μm at a coating weight of 100 g/m2 per side. Then, an obtained coated film was dried. In this way, a negative electrode including the negative electrode current collector and the layer containing negative electrode active material provided on both surfaces of the negative electrode current collector was obtained.

<PRODUCTION OF INSULATING PARTICLE LAYER>

[282] Li7La3Zr2O12 (average particle size: 5 μm) was provided as inorganic compound particles that have lithium ion conductivity. The particles and polyvinylidene fluoride (PVdF) as a binder were mixed so that the mass ratio was 100:3 and dispersed with N-methylpyrrolidone (NMP) as a dispersion medium, in which a first aqueous slurry was prepared.

[283] Through the use of an gravure coater, the first aqueous paste was coated on one of the previously produced negative electrode active material-containing layers, and a coated film obtained was dried. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 10 μm.

[284] Furthermore, Li7La3Zr2O12 (average particle size: 15 μm) was provided as inorganic compound particles that have lithium ion conductivity. The particles and polyvinylidene fluoride (PVdF) as a binder were mixed so that the mass ratio was 100:6 and dispersed with N-methylpyrrolidone (NMP) as a dispersion medium, in which a second aqueous slurry was prepared.

[285] Then, the second aqueous paste was coated on the first coated film using a gravure coater, and the coated film was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 20 μm.

[286] By repeating the same procedure as above, a first coated film was formed on the other negative electrode active material layer of the negative electrode, and a second coated film was additionally formed on the first coated film.

[287] Subsequently, pressure treatment was carried out from the second coated film to the negative electrode current collector. Pressure treatment was carried out using a cylinder pressure machine at a linear pressure of 2.0 kN/cm. In this way, the electrode composite of Example 1 was obtained. This electrode composite included the negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.08 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.6 g/cm3.

[288] In Example 1, a non-aqueous electrolyte battery was produced using the electrode composite of Example 1 by the following procedure.

<POSITIVE ELECTRODE PRODUCTION>

[289] First, a composite lithium cobalt oxide powder (LiCoO2) as a positive electrode active material, acetylene black and graphite as conducting agents, and polyvinylidene fluoride (PVdF) as a binder were provided.

[290] 90% by mass of lithium cobalt oxide composite, 3% by mass of acetylene black, 3% by mass of graphite and 4% by mass of PVdF were added to N-methylpyrrolidone (NMP) as a solvent and mixed to prepare an aqueous positive electrode slurry.

[291] This positive electrode aqueous paste was coated on both surfaces of a current collector formed from an aluminum foil having a thickness of 15 μm and an average crystal grain size of 30 μm. Then, an obtained coated film was dried and pressed. Pressure treatment was carried out using a cylinder pressure machine at a linear pressure of 1.5 kN/cm. In this way, a positive electrode including a positive electrode current collector and a layer containing positive electrode active material formed on the positive electrode current collector was obtained. The density of the layer containing positive electrode active material of the obtained positive electrode was about 3.0 g/cm3. Furthermore, the average surface roughness Ra of the surface of the layer containing positive electrode active material that was not in contact with the positive electrode current collector was 0.15 μm.

<GEL NON-AQUEOUS ELECTROLYTE PRECURSOR PREPARATION>

[292] Ethylene carbonate and diethyl carbonate were mixed in a volume ratio of 1:2 to prepare a liquid non-aqueous solvent.

[293] Lithium hexafluorophosphate (LiPF6) as an electrolyte was dissolved in the liquid non-aqueous solvent at a concentration of 1.51 mol/L. In this way, a liquid non-aqueous electrolyte was prepared.

[294] Then, this liquid non-aqueous electrolyte was mixed with polyacrylonitrile (PAN) monomer and stirred. At this time, the mass ratio of liquid non-aqueous electrolyte to PAN was 2:1. In this way, a gel non-aqueous electrolyte precursor was prepared. This precursor was in a liquid state.

<BATTERY PRODUCTION>

[295] A negative electrode cable was attached to the negative electrode current collector of the electrode composite produced as described above. Similarly, a positive electrode cable was attached to the positive electrode current collector of the positive electrode produced as described above.

[296] Then, the electrode composite and the positive electrode were stacked. At this time, the second surface of one of the insulating particle layers of the electrode composite was in contact with one of the layers containing positive electrode active material of the positive electrode. In this way, a group of electrodes was obtained. This group of electrodes was placed in a container made of laminated film.

[297] Then, the previously prepared non-aqueous gel electrolyte precursor was injected into the electrode group. Then, the container housing the group of electrodes was placed in a vacuum chamber, and the pressure in the chamber was reduced. By this operation, the non-aqueous gel electrolyte precursor was maintained in the electrode group. Then the container was sealed.

[298] The container was then transferred to a thermostat chamber at 65 °C. here, the container was left for 15 hours. In this way, the precursor maintained in the electrode group was converted into a non-aqueous gel electrolyte. In other words, a portion of the non-aqueous gel electrolyte was maintained in the insulating particle layer of the electrode composite.

[299] Then, the container was placed in a chamber of a pressure reducing device and opened into the chamber. The pressure in the chamber has been reduced while keeping the container open. Then, the container was sealed while maintaining reduced pressure in the chamber. In this way, the container was vacuum sealed. In this way, the non-aqueous electrolyte battery of Example 1 was produced.

(EXAMPLE 2)

[300] In Example 2, an electrode composite of Example 2 was produced by the same procedure as in Example 1, except for the use of Li7La3Zr2O12 inorganic compound particles that have an average particle size different from those used in Example 1.

[301] Specifically, in Example 2, when preparing a first aqueous paste, Li7La3Zr2O12 which has an average particle size of 8 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous paste prepared in Example 2 was coated on a layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dry. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 15 μm.

[302] In Example 2, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 25 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Example 2 was coated on the first coated film in the same way as in Example 1, and a coated film obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 35 μm.

[303] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.0 kN/cm. By this pressure, the electrode composite of Example 2 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.1 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.6 g/cm3.

[304] In Example 2, a non-aqueous electrolyte battery of Example 2 was produced by the same procedure as in Example 1 except for the use of the electrode composite of Example 2.

(EXAMPLE 3)

[305] In Example 3, an electrode composite of Example 3 was produced by the same procedure as in Example 1 except for the use of Li7La3Zr2O12 inorganic compound particles that have an average particle size different from those used in Example 1.

[306] Specifically, in example 3, when preparing a first aqueous slurry, Li7La3Zr2O12 which has an average particle size of 3 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous paste prepared in Example 3 was coated on a layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dry. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 20 μm.

[307] In example 3, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 20 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Example 3 was coated on the first coated film in the same way as in Example 1, and a coated film obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 35 μm.

[308] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.5 kN/cm. By this pressure, the electrode composite of Example 3 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface in contact with each of the layers containing negative electrode active material and an opposing second surface. The surface roughness of the second surface was 0.06 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.6 g/cm3.

[309] In Example 3, a non-aqueous electrolyte battery of Example 3 was produced by the same procedure as in Example 1 except for the use of the electrode composite of Example 3.

(EXAMPLE 4)

[310] In example 4, a non-aqueous electrolyte battery of Example 4 was produced by the following procedure.

[311] First, in Example 4, two electrode composites were produced by the same procedure as in Example 1.

[312] Then, with the use of each of the electrode composites, two groups of electrodes were produced by the same procedure as in Example 1.

[313] Then, each of the electrode groups was placed in a separate container. Then, by the same procedure as in Example 1, a precursor of a non-aqueous gel electrolyte was retained in the group of electrodes housed in each container. Then, the precursor maintained in the electrode group was converted into a non-aqueous gel electrolyte by the same procedure as in Example 1.

[314] Then, the groups of electrodes were removed from the container and connected in series. These groups of electrodes were placed in a container formed from a laminate film. Then, this container was placed in a chamber of a pressure reducing device, and here, the container was vacuum sealed by the same procedure as in Example 1. In this way, the non-aqueous electrolyte battery of Example 4 was obtained.

(EXAMPLE 5)

[315] In Example 5, an electrode composite of Example 5 was produced by the same procedure as in Example 1 except for the following points.

[316] First, in example 5, a negative electrode that includes a negative electrode current collector and a layer containing negative electrode active material formed on both surfaces of the negative electrode current collector was produced by the same procedure as in Example 1 except for the use of an Nb2TiO7 powder that has an average secondary particle size of 12 μm and that has a lithium insertion and extraction potential greater than 1.0 V relative to the redox potential of lithium.

[317] In example 5, Li7La3Zr2O12 inorganic compound particles that have an average particle size different from those used in Example 1 were used.

[318] Specifically, in example 5, when preparing a first aqueous slurry, Li7La3Zr2O12 which has an average particle size of 1 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous paste prepared in example 5 was coated on the layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dried . In this way, a first coated film was obtained. The thickness of the first coated film after drying was 15 μm.

[319] In example 5, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 15 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Example 5 was coated on the first coated film in the same way as in Example 1, and a coated film obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 20 μm.

[320] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.3 kN/cm. By this pressure, the electrode composite of Example 5 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.05 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.63 g/cm3.

[321] In Example 5, a non-aqueous electrolyte battery of Example 5 was produced by the same procedure as in Example 1 except for the use of the electrode composite of Example 5.

(EXAMPLE 6)

[322] In example 6, an electrode composite from Example 6 was produced by the same procedure as in Example 1, except that the inorganic compound particles used were changed from Li7La3Zr2O12 to Li1.3Al0.3Ti1.7(PO4).

[323] Specifically, in example 6, when preparing a first aqueous slurry, Li1.3Al0.3Ti1.7(PO4) which has an average particle size of 5 μm was used. The mixing ratio of Li1.3Al0.3Ti1.7(PO4) and PVdF was the same as in Example 1. The first aqueous paste prepared in example 6 was coated on the layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dried. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 10 μm.

[324] In example 6, when preparing a second aqueous slurry, Li1.3Al0.3Ti1.7(PO4) which has an average particle size of 20 μm was used. The mixing ratio of Li1.3Al0.3Ti1.7(PO4) and PVdF was the same as in Example 1. The second aqueous paste prepared in Example 6 was coated on the first coated film in the same way as in Example 1, and a film coat obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 25 μm.

[325] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.2 kN/cm. By this pressure, the electrode composite of Example 6 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.05 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.61 g/cm3.

[326] In Example 6, a non-aqueous electrolyte battery of Example 6 was produced by the same procedure as in Example 1 except for the use of the electrode composite of Example 6.

(EXAMPLE 7)

[327] In Example 7, an electrode composite of Example 7 was produced by the same procedure as in Example 1, except for the following points.

[328] First, in example 7, a negative electrode that includes a negative electrode current collector and a layer containing negative electrode active material formed on both surfaces of the negative electrode current collector was produced by the same procedure as in Example 1 except for the use of an Nb2TiO7 powder that has an average secondary particle size of 15 μm and that has a lithium insertion and extraction potential greater than 1.0 V relative to the redox potential of lithium.

[329] In Example 7, Li7La3Zr2O12 inorganic compound particles that have an average particle size different from those used in Example 1 were used.

[330] Specifically, in example 7, when preparing a first aqueous slurry, Li7La3Zr2O12 which has an average particle size of 1 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous paste prepared in example 7 was coated on the layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dried . In this way, a first coated film was obtained. The thickness of the first coated film after drying was 10 μm.

[331] In example 7, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 20 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Example 7 was coated on the first coated film in the same way as in Example 1, and a coated film obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 30 μm.

[332] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.0 kN/cm. By this pressure, the electrode composite of Example 7 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.07 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.6 g/cm3.

[333] In Example 7, a non-aqueous electrolyte battery of Example 7 was produced by the same procedure as in Example 1, except for the use of the electrode composite of Example 7.

COMPARATIVE EXAMPLE 1

[334] In Comparative Example 1, an electrode composite of Comparative Example 1 was produced by the same procedure as in Example 1 except for the use of Li7La3Zr2O12 inorganic compound particles that have an average particle size different from those used in Example 1.

[335] Specifically, in Comparative Example 1, when preparing a first aqueous paste, Li7La3Zr2O12 which has an average particle size of 1 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous slurry prepared in Comparative Example 1 was coated on a layer containing negative electrode active material in the same manner as in Example 1, and a coated film obtained it was dry. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 5 μm.

[336] In Comparative Example 1, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 50 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Comparative Example 1 was coated on the first coated film in the same way as in Example 1, thereby obtaining a second coated film. The thickness of the second coated film was 80 μm.

[337] Pressing to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.0 kN/cm. By this pressing, the electrode composite of Comparative Example 1 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.5 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.6 g/cm3.

[338] In Comparative Example 1, a non-aqueous electrolyte battery of Comparative Example 1 was produced by the same procedure as in Example 1, except for the use of the electrode composite of Comparative Example 1.

COMPARATIVE EXAMPLE 2

[339] In Comparative Example 2, an electrode composite of Comparative Example 2 was produced by the same procedure as in Example 1, except that only a first aqueous paste was coated to produce an insulating particle layer. That is, in Comparative Example 2, a second water slurry was not used.

[340] In Comparative Example 2, the thickness of a first coated film after drying was 30 μm.

[341] Pressing to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.0 kN/cm. By this pressing, the electrode composite of Comparative Example 2 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.12 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.6 g/cm3.

[342] In Comparative Example 2, a non-aqueous electrolyte battery of Comparative Example 2 was produced by the same procedure as in Example 1, except for the use of the electrode composite of Comparative Example 2.

COMPARATIVE EXAMPLE 3

[343] In Comparative Example 3, an electrode composite of Comparative Example 3 was produced by the same procedure as in Example 1 except for the following points.

[344] First, in Comparative Example 3, a negative electrode that includes a negative electrode current collector and a layer containing negative electrode active material formed on both surfaces of the negative electrode current collector was produced by the same procedure as in example 5.

[345] In Comparative Example 3, Li7La3Zr2O12 inorganic compound particles having an average particle size different from those used in Example 1 were used.

[346] Specifically, in Comparative Example 3, when preparing a first aqueous paste, Li7La3Zr2O12 which has an average particle size of 1 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous paste prepared in Comparative Example 3 was coated on the layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dry. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 10 μm.

[347] In Comparative Example 3, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 15 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Comparative Example 3 was coated on the first coated film in the same way as in Example 1, and a coated film obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 60 μm.

[348] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 2.0 kN/cm. By this pressing, the electrode composite of Comparative Example 3 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.2 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.6 g/cm3.

[349] In Comparative Example 3, a non-aqueous electrolyte battery of Comparative Example 3 was produced by the same procedure as in Example 1 except for the use of the electrode composite of Comparative Example 3.

(Comparative Example 4)

[350] In Comparative Example 4, an electrode composite of Comparative Example 3 was produced by the same procedure as in Example 1, except for the following points.

[351] First, in Comparative Example 4, a negative electrode that includes a negative electrode current collector and a layer containing negative electrode active material formed on both surfaces of the negative electrode current collector was produced by the same procedure as in example 5.

[352] In Comparative Example 4, Li7La3Zr2O12 inorganic compound particles having an average particle size different from those used in Example 1 were used.

[353] Specifically, in Comparative Example 4, when preparing a first aqueous paste, Li7La3Zr2O12 which has an average particle size of 5 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous paste prepared in Comparative Example 4 was coated on the layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dry. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 10 μm.

[354] In Comparative Example 4, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 50 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Comparative Example 4 was coated on the first coated film in the same way as in Example 1, and a coated film obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 70 μm.

[355] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 1.3 kN/cm. By this pressing, the electrode composite of Comparative Example 4 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.35 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.35 g/cm3.

[356] In Comparative Example 4, a non-aqueous electrolyte battery of Comparative Example 4 was produced by the same procedure as in Example 1 except for the use of the electrode composite of Comparative Example 4.

(Comparative Example 5)

[357] In Comparative Example 5, an electrode composite of Comparative Example 3 was produced by the same procedure as in Example 1, except for the following points.

[358] First, in Comparative Example 5, a negative electrode that includes a negative electrode current collector and a layer containing negative electrode active material formed on both surfaces of the negative electrode current collector was produced by the same procedure as in example 5.

[359] In Comparative Example 5, Li7La3Zr2O12 inorganic compound particles having an average particle size different from those used in Example 1 were used.

[360] Specifically, in Comparative Example 5, when preparing a first aqueous paste, Li7La3Zr2O12 which has an average particle size of 15 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The first aqueous paste prepared in Comparative Example 5 was coated on the layer containing negative electrode active material in the same way as in Example 1, and a coated film obtained was dry. In this way, a first coated film was obtained. The thickness of the first coated film after drying was 20 μm.

[361] In Comparative Example 5, when preparing a second aqueous slurry, Li7La3Zr2O12 which has an average particle size of 15 μm was used. The mixing ratio of Li7La3Zr2O12 and PVdF was the same as in Example 1. The second aqueous paste prepared in Comparative Example 5 was coated on the first coated film in the same way as in Example 1, and a coated film obtained was dried. In this way, a second coated film was obtained. The thickness of the second coated film after drying was 20 μm.

[362] Pressure treatment to obtain an electrode composite was carried out using a cylinder pressure machine at a linear pressure of 1.6 kN/cm. By this pressing, the electrode composite of Comparative Example 5 was obtained. This electrode composite included a negative electrode and an insulating particle layer in contact with each layer containing negative electrode active material. Each of the insulating particle layers had a first surface and a second surface opposite the first surface. The first surface was in contact with each of the layers containing negative electrode active material. The surface roughness of the second surface was 0.25 μm as measured by the method described above. The density of the layer containing negative electrode active material was 2.5 g/cm3.

[363] In Comparative Example 5, a non-aqueous electrolyte battery of Comparative Example 5 was produced by the same procedure as in Example 1, except for the use of the electrode composite of Comparative Example 5.

<TEST>

[364] The non-aqueous electrolyte battery produced as described above was subjected to the following test. Hereinafter, the battery to be tested is merely described as a “battery,” but each of the non-aqueous electrolyte batteries in the example and the Comparative Example was tested in the same manner by the following procedure.

[365] The battery was charged at a constant current of 0.2 C under a 25 °C environment until the voltage reached 2.8 V. Then, the battery was subjected to charging at a constant voltage of 2.8 V until the full charging time reached 10 hours. Then, the battery was subjected to discharge at a constant current of 0.2 C until the voltage reached 1.5 V. The discharge capacity under constant current discharge was taken as a capacity A [Ah].

[366] Then, the battery was charged at a constant current of 1 C until the voltage reached 2.8 V. Then, the battery was subjected to charging at a constant voltage of 2.8 V until the full charging time reached 3 hours. Then, the battery was subjected to discharge at a constant current of 3 C until the voltage reached 1.5 V. The discharge capacity under constant current discharge was considered a B [Ah] capacity.

[RESULT]

[367] In relation to examples 1 to 7 and Comparative Examples 1 to 5, the average particle size of the negative electrode active material secondary particles, the surface roughness Ra of the second surface of the insulating particle layer and the capacities A and B measurements in the above test are shown in Table 1 below. It should be noted that the capacity A of each battery is shown as a relative value with the capacity A of the non-aqueous electrolyte battery of Example 1 set to 100. The capacity B of each battery is also shown as a relative value with the capacity B of the non-aqueous electrolyte battery of Example 1 considered, set to 100. [TABLE 1]

[368] From the results shown in Table 1, it was found that the discharge capacity A at 0.2 C of each of the batteries in Examples 1 to 7 was greater than that of each of the batteries in Comparative Examples 2 and 5. Furthermore, it was found that the discharge capacity B at 3 C of each of the batteries of Examples 1 to 7 was greater than that of each of the batteries of Comparative Examples 1 to 5.

[369] From these results, it is understood that the batteries of Examples 1 to 7 were capable of exhibiting more excellent output performance than the batteries of Comparative Examples 1 to 5.

[370] When the batteries after testing were examined in detail, it was found that the resistance values of the batteries of Comparative Examples 1, 3 and 4 were twice or more of those of the batteries of Examples 1 to 7. This is considered as a of the reasons why the discharge capacities B in 3 C of the batteries of Comparative Examples 1, 3 and 4 were lower than those of the batteries of Examples 1 to 7.

[371] When the batteries of Comparative Examples 2 and 5 were examined after testing, it was found that an electrical short circuit partially occurred between the positive electrode and the negative electrode. Therefore, it can be considered that the batteries in Comparative Examples 2 and 5 did not have the ability to be smoothly charged and discharged. This is considered as one of the reasons why the discharge capacity A at 0.2 C and the discharge capacity B at 3 C of each of the batteries of Comparative Examples 2 and 5 were lower than those of the batteries of Examples 1 to 7.

[372] According to at least one embodiment and example described above, a composite electrode is provided. This electrode composite includes a layer containing negative electrode active material and an insulating particle layer. The layer containing negative electrode active material includes secondary particles of negative electrode active material. The average secondary particle size of negative electrode active material secondary particles is 1 μm to 30 μm. The insulating particle layer includes inorganic compound particles. The insulating particle layer is provided in the layer containing negative electrode active material. The insulating particle layer has a first surface and a second surface opposite the first surface. The first surface is in contact with the layer containing negative electrode active material. The surface roughness of the second surface of the insulating particle layer is 0.1 μm or less. When this electrode composite is used in a secondary battery, an electrical short circuit between the layer containing negative electrode active material and the positive electrode and side reactions of the negative electrode active material secondary particles with the electrolyte can be suppressed. As a result, the electrode composite can design a secondary battery that can exhibit excellent output performance.

[373] Although certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the innovative embodiments described herein can be incorporated in a variety of other forms; Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The appended claims and their equivalents are intended to cover such forms or modifications as would be within the scope and spirit of the inventions.

Claims (10)

1. Electrode composite (10, 10A, 10B, 10C, 10D) characterized by the fact that it comprises: a layer containing negative electrode active material (3b) comprising secondary particles of negative electrode active material (3A) having an average secondary particle size of 1 μm to 30 μm, the average secondary particle size being determined by selecting 50 secondary particles of negative electrode active material from a scanning electron microscopic image of the layer containing negative electrode active material (3b) and by measuring a volume average secondary particle size from the selected secondary particles, and the negative electrode active material secondary particles (3A) comprising titanium-containing oxide particles; and an insulating particle layer (4) provided on the layer containing negative electrode active material (3b) and comprising inorganic compound particles comprising lithium ion conductive particles, wherein the insulating particle layer (4) comprises a first surface (4-1) and a second surface (4-2) opposite the first surface (4-1), wherein the first surface (4-1) is in contact with the layer containing negative electrode active material (3b ), and the second surface (4-2) has a surface roughness Ra of 0.1 μm or less, the surface roughness Ra of the second surface being determined using a surface roughness measuring instrument by performing measurements five times with a value of cut-off value set at 0.25 mm, or when the surface roughness Ra is greater than 0.1 μm with a cut-off value set at 0.8 mm, and taking an average value of five measurement results as the surface roughness Ra of the second surface. 2. Electrode composite (10, 10A, 10B, 10C, 10D), according to claim 1, characterized in that a thickness of the insulating particle layer (4) is 10 μm to 40 μm. 3. Electrode composite (10, 10A, 10B, 10C, 10D), according to claim 1 or 2, characterized in that the titanium-containing oxide particles comprise at least one type of particles selected from the group which consists of particles of a lithium titanate having a spinel-type crystal structure, particles of a lithium titanate having a ramsdelite-type crystal structure, particles of a titanium-niobium composite oxide, particles of a of titanium which has a monoclinic crystal structure, and particles of a titanium dioxide which has an anatase-type crystal structure. 4. Electrode composite (10, 10A, 10B, 10C, 10D), according to any one of claims 1 to 3, characterized in that it additionally comprises: a current collector (8a) comprising a third surface (8a -1) and a fourth surface (8a-2) opposite the third surface (8a-1), wherein the layer containing negative electrode active material (3b) is provided on the third surface (8a-2); and a layer containing positive electrode active material (5b) provided on the fourth surface (8a-2). 5. Secondary battery (100) characterized by the fact that it comprises: the electrode composite (10, 10A, 10B, 10C, 10D), as defined in any one of claims 1 to 3; and a positive electrode (5) comprising a layer containing active material of positive electrode (5b), wherein the second surface (4-2) of the insulating particle layer (4) is in contact with the layer containing active material positive electrode (5b). 6. Secondary battery (100) characterized by the fact that it comprises a first electrode composite (10B) and a second electrode composite (10A) located proximal to the first electrode composite (10B), wherein the first and second electrode composites (10B) electrode (10B, 10A) are composite electrodes (10, 10A, 10B, 10C, 10D), each as defined in claim 4, wherein the second surface (4-2) of the insulating particle layer (4) of the first electrode composite (10B) is in contact with the layer containing positive electrode active material (5b) of the second electrode composite (10A). 7. Secondary battery (100), according to claim 5 or 6, characterized by the fact that it additionally comprises a non-aqueous gel electrolyte maintained in the insulating particle layer (4). 8. Battery assembly (300, 300a, 300b, 300c) characterized by the fact that it comprises the secondary battery (100), as defined in any one of claims 5 to 7. 9. Battery assembly (300, 300a, 300b, 300c), according to claim 8, characterized in that it additionally comprises: an external power distribution terminal (347); and a protective circuit (344). 10. Battery assembly (300, 300a, 300b, 300c), according to claim 8 or 9, characterized by the fact that it comprises a plurality of secondary batteries (100), wherein the plurality of secondary batteries (100) is electrically connected in series, parallel or a combination of series and parallel.