阅读说明：本技术 二次电池及其制造方法 (Secondary cell and its manufacturing method ) 是由 万久俊彦 于 2018-02-28 设计创作，主要内容包括：本发明的一个目的在于提供一种二次电池及其制造方法,其维持电极之间的高绝缘性并且可以有效地抑制内部短路。这种二次电池包含正极和面对所述正极配置的负极。所述正极和所述负极各自具有集电器和在所述集电器的至少一个表面上形成的活性材料层,并且所述正极和所述负极中的至少一者还具有在所述活性材料层的表面上形成的绝缘层。所述绝缘层是含有多个非导电性粒子的多孔绝缘层,并且当以μm表示所述粒子的平均粒径时,由所述粒子的孔隙率×平均粒径表示的孔隙率指数为0.4以下。(It is an object of the present invention to provide a kind of secondary cell and its manufacturing methods, maintain the high-insulativity between electrode and can effectively inhibit internal short-circuit.This secondary cell includes anode and the cathode in face of the anode configuration.The active material layer that the anode and the cathode respectively have current-collector and formed at least one surface of the current-collector, and at least one of the anode and the cathode also have the insulating layer formed on the surface of the active material layer.The insulating layer is the porous dielectric layer containing multiple non-conductive particles, and when μm to indicate the average grain diameter of the particle, is 0.4 or less by the porosity index that porosity × average grain diameter of the particle indicates.)

1. a kind of secondary cell, includes:

Anode；With

The cathode configured in face of the anode,

Wherein the anode and the cathode respectively contain current-collector and are formed at least one surface of the current-collector Active material layer, and at least one of the anode and the cathode also include shape on the surface of the active material layer At insulating layer, and

The insulating layer is the porous dielectric layer containing multiple non-conductive particles, and when the particle average grain diameter by μm It is 0.4 or less by the porosity index that average grain diameter × porosity of the particle indicates when expression.

2. secondary cell according to claim 1, wherein the average grain diameter of the non-conductive particles is 0.4 μm~5 μm.

3. secondary cell according to claim 1 or 2, wherein also comprising configuration between the anode and the cathode Diaphragm, and

Percent thermal shrinkage of the diaphragm at 200 DEG C is less than 5%, and Ge Erlai value is 10 seconds/100ml or less.

4. a kind of manufacturing method of secondary cell, which comprises

Prepare anode and cathode, and

By it is described anode and the cathode be configured to it is facing with each other,

Wherein the anode and the cathode respectively contain current-collector and are formed at least one surface of the current-collector Active material layer, and at least one of the anode and the cathode also include shape on the surface of the active material layer At insulating layer, and

The insulating layer is the porous dielectric layer containing multiple non-conductive particles, and when the particle average grain diameter by μm It is 0.4 or less by the porosity index that average grain diameter × porosity of the particle indicates when expression.

5. the manufacturing method of secondary cell according to claim 4, wherein the average grain diameter of the non-conductive particles is 0.4 μm~5 μm.

6. the manufacturing method of secondary cell according to claim 4 or 5, wherein the anode and the cathode are configured to It is facing with each other to include

Percent thermal shrinkage of the configuration at 200 DEG C is less than 5% between the anode and the cathode and Ge Erlai value is 10 Second/100ml diaphragm below.

Technical field

The present invention relates to wherein at least one of anode and cathode with the secondary electricity of insulating layer on active material layer The manufacturing method of pond and the secondary cell.

Background technique

Secondary cell is widely used as portable electronic device such as smart phone, tablet computer, laptop, digital phase The power supply of machine etc..In addition, the purposes of secondary cell has extended to the power supply and domestic power supply as electric vehicle.Wherein, lithium For ion secondary battery since energy density is high and light-weight, they are indispensable energy storage devices in current life.In In this kind of secondary cell with high-energy density, it is desirable that high security technology is especially to ensure that the safety of internal short-circuit is Important.

Conventional batteries (including secondary cell) have anode and cathode as electrode in the case where diaphragm is placed in therebetween Structure facing with each other.Anode and cathode respectively have sheet current-collector and are formed in the active material layer on current-collector two sides.Every Film is used to prevent the short circuit between anode and cathode and effectively moves ion between a positive electrode and a negative electrode.In the past, mainly made Use the micro-pore septum of the polyolefin made of polypropylene or polythene material as diaphragm.However, polypropylene and polyethylene material The fusing point of material is usually 110 DEG C to 160 DEG C.Therefore, when the battery for being used for the diaphragm of polyolefin that there is high-energy density, The diaphragm melts at a high temperature of battery, and may occurrence of large-area electrode between short circuit, cause battery smolder and Kindling.

Therefore, in order to improve the safety of secondary cell, patent document 1 (Japanese Unexamined Patent Publication 2003-123728 bulletin) is public A kind of secondary cell is opened, septation is made of the non-woven fabrics of the fiber with special diameter containing specific quantity.

Patent document 2 (table public again of PCT international publication WO 2005/067079) and (the PCT international publication WO of patent document 3 2005/098997 table public again) a kind of secondary cell is disclosed, wherein at least one of anode and cathode have on the surface thereof There is the porous insulating film containing inorganic oxide filler and adhesive.In particular, in the secondary cell that patent document 2 describes, Diaphragm is made of non-woven fabrics, and in the secondary cell that patent document 3 describes, the porosity of diaphragm and porous dielectric layer is obtained Optimization.

The diaphragm made of non-woven fabrics is expected can be used as and is for example adapted under low temperature because of its good ionic conductivity The diaphragm of height output.In addition, improving height by the way that porous insulating film is arranged on surface of the anode at least one of cathode Insulating property (properties) when warm.

Summary of the invention

Technical problem

However, when using non-woven fabrics as diaphragm, due to the metal that is precipitated in electrolyte during charging and electrode Microspike or burr etc. penetrate readily through diaphragm, it is thus possible to internal short-circuit occur.Therefore, it is only difficult to ensure and is filled with the diaphragm The insulating properties divided.It is therefore contemplated that the insulating materials of such as aluminium oxide is coated on the surface of nonwoven cloth diaphragm to prevent from filling Internal short-circuit during electricity.However, in this case, since non-woven fabrics softens at high temperature, the insulating layer of coating can It can be destroyed by external force, it is possible to be unable to maintain that insulating properties.

On the other hand, when combining the porous insulating film above formed at least one of anode and cathode with diaphragm, If diaphragm has big percent thermal shrinkage, diaphragm is shunk at a high temperature of battery because of heat, and the contraction of diaphragm may be led Cause porous insulating film that may remove from electrode surface.As a result, the insulating properties under high temperature cannot be maintained, and internal short-circuit occurs.

It is the object of the present invention is to provide a kind of high-insulativity being able to maintain that between electrode and more effectively short inside inhibition The secondary cell and its manufacturing method on road.

Technical solution

Secondary cell according to the present invention includes:

Anode；With

The cathode configured in face of the anode,

Wherein the anode and the cathode respectively contain current-collector and the shape at least one surface of the current-collector At active material layer, and the anode and at least one of described cathode are also included in the surface of the active material layer The insulating layer of upper formation, and

The insulating layer is the porous dielectric layer containing multiple non-conductive particles, and works as the average grain diameter of the particle By μm indicate when, by the particle average grain diameter × porosity indicate porosity index be 0.4 or less.

The manufacturing method of secondary cell according to the present invention includes:

Prepare anode and cathode；With

By it is described anode and the cathode be configured to it is facing with each other,

Wherein the anode and the cathode respectively contain current-collector and the shape at least one surface of the current-collector At active material layer, and the anode and at least one of described cathode are also included in the surface of the active material layer The insulating layer of upper formation, and

The insulating layer is the porous dielectric layer containing multiple non-conductive particles, and works as the average grain diameter of the particle By μm indicate when, by the particle average grain diameter × porosity indicate porosity index be 0.4 or less.

Beneficial effects of the present invention

According to the present invention, by using in the secondary cell on the surface of electrode with insulating layer with specific structure Insulating layer can maintain the high-insulativity between electrode and can inhibit internal short-circuit.

Detailed description of the invention

[Fig. 1] Fig. 1 is the decomposition perspective view of secondary cell according to one embodiment of the present invention.

[Fig. 2] Fig. 2 is the schematic sectional view of cell device shown in Fig. 1.

[Fig. 3] Fig. 3 is the schematic sectional view for showing the construction of anode and cathode shown in Fig. 2.

[Fig. 4 A] Fig. 4 A is the sectional view for showing the example of the configuration of anode and cathode in cell device.

[Fig. 4 B] Fig. 4 B is the sectional view for showing another example of the configuration of anode and cathode in cell device.

[Fig. 5] Fig. 5 is the decomposition perspective view of the secondary cell of another embodiment according to the present invention.

[Fig. 6] Fig. 6 is the schematic diagram for showing the example of the electric vehicle equipped with secondary cell.

[Fig. 7] Fig. 7 is the schematic diagram for showing the example of the electrical storage device equipped with secondary cell.

Specific embodiment

Referring to Fig.1, it is shown that the decomposition perspective view of secondary cell 1 according to one embodiment of the present invention, it is described secondary Battery includes cell device 10 and the shell for encapsulating cell device 10 together with electrolyte.The shell has housing member 21,22, the two sides of thickness direction of the housing member 21,22 from cell device 10 are surrounded and are sealed its outer peripheral portion, To sealed cell element 10 and electrolyte.Positive terminal 31 and negative terminal 32 respectively with they from the protrusion of shell with Cell device 10 connects.

As shown in Fig. 2, cell device 10 have plurality of positive 11 and multiple cathode 12 be configured to it is facing with each other to The construction being alternately arranged.In addition, diaphragm 13 configures between anode 11 and cathode 12, to ensure between anode 11 and cathode 12 Ionic conduction and prevent anode 11 and cathode 12 between short circuit.However, diaphragm 13 is not required in the present embodiment.

The structure of anode 11 and cathode 12 will be referred to further Fig. 3 and be described.In structure shown in Fig. 3, without spy Not Qu Fen anode 11 and cathode 12, but anode 11 and the applicable structure of cathode 12.Anode 11 and cathode 12 (are not being distinguished They can be referred to as " electrode " in the case where them) comprising can be by current-collector 110 that metal foil is formed and in current-collector The active material layer 111 formed on 110 one or two surface.Active material layer 111 is preferably formed as square when looking down Shape shape, and current-collector 110 has the shape of the extension 110a comprising extending from the region for being formed with active material layer 111 Shape.

In the state that anode 11 and cathode 12 are laminated, the anode 11 extension 110a and extension 110a of cathode 12 It is formed at the position to overlap each other.However, the extension 110a of anode 11 is in the position that overlaps each other, and cathode 12 Extension 110a is also identical.Utilize this configuration of extension 110a, in the multiple positive 11, each extension 110a quilt It concentrates and welds together and form positive pole ear 10a.Equally, in the multiple cathode 12, each extension 110a is collected In and weld together and form negative lug 10b.Positive terminal 31 is electrically connected with positive pole ear 10a, and negative terminal 32 It is electrically connected with negative lug 10b.

Positive at least one of 11 and cathode 12 also include the insulating layer 112 formed on active material layer 111.Insulation Layer 112 is formed so that does not expose active material layer 111 when looking down.Current-collector 110 is formed in active material layer 111 In the case where on two surfaces, insulating layer 112 can be formed on two active material layers 111, or can be only in a work It is formed in property material layer 111.

Some examples of the configuration of the anode 11 and cathode 12 that have a structure in which are illustrated in figures 4A and 4 B.In Fig. 4 A Shown in configuration, by two sides have insulating layer 112 anode 11 and not no insulating layer cathode 12 it is alternately laminated.In Fig. 4 B institute In the configuration shown, so that the mode not facing with each other of each insulating layer 112 will be only in one side with the anode 11 of insulating layer 112 It is alternately laminated with cathode 12.In the structure shown in Fig. 4 A and Fig. 4 B, due to there is insulation between anode 11 and cathode 12 Layer 112, therefore diaphragm 13 can be saved.

The structure and configuration of anode 11 and cathode 12 are not limited to examples detailed above, and various modifications are all possible, as long as Insulating layer 112 is arranged on a surface of at least one of anode 11 and cathode 12.For example, shown in Fig. 4 A and 4B Structure in, anode 11 and cathode 12 between relationship can reverse.

Since the cell device 10 of the plane stepped construction with diagram does not have the part of small radius of curvature (close to volume Around the region of the winding core of structure), therefore compared with the cell device with winding-structure, cell device 10, which has, to be not easily susceptible to The advantages of influence of the variation of the electrode volume due to caused by charge and discharge.That is, the cell device with plane stepped construction It is effectively used for the electrode assembly using the active material for being easy to cause volume expansion.

In the embodiment shown in Fig. 1 and 2, positive terminal 31 and negative terminal 32 are drawn in the opposite direction, but just The direction that extreme son 31 and negative terminal 32 are brought out can be arbitrary.For example, as shown in figure 5, positive terminal 31 and cathode Terminal 32 can be drawn on one side from the same of cell device 10.Although being not shown, positive terminal 31 and negative terminal 32 can also To be drawn from two adjacent edges of cell device 10.In above-mentioned two situations, positive pole ear 10a and negative lug 10b can be with It is formed at the corresponding position in the direction that is brought out with positive terminal 31 and negative terminal 32.

In addition, in the illustrated embodiment, the stepped construction with multiple positive 11 and multiple cathode 12 is shown Cell device 10.However, the cell device with winding-structure can have an anode 11 and a cathode 12.

Hereinafter, it will be explained in constituting the component and electrolyte of cell device 10.In the following description, although not having Especially limitation, but each element that will illustrate in lithium ion secondary battery.

[1] cathode

Cathode has for example such as flowering structure, and wherein negative electrode active material is adhered to negative electrode current collector by negative electrode binder, And negative electrode active material is layered in negative electrode current collector as anode active material layer.As long as not damaging effect of the invention significantly Fruit, then it is living to can be used as the cathode in present embodiment for any material that can absorb and release lithium ion with charge and discharge Property material.In general, cathode is constructed also by anode active material layer is arranged on current-collector as the situation of anode.With Anode is similar, and cathode can also suitably have other layers.

Negative electrode active material is not particularly limited, and can as long as it is can to absorb and release the material of lithium ion Arbitrarily use known negative electrode active material.For example, it is preferable to use the carbon of coke, acetylene black, interphase microballoon, graphite etc. Material；Lithium metal；The lithium alloy of lithium-silicon, lithium-tin etc.；Lithium titanate etc. is used as negative electrode active material.Wherein, from good Cycle characteristics and safety and trickle charge characteristic it is more excellent from the viewpoint of, most preferably with carbonaceous material.It can be single A kind of negative electrode active material is solely used, or the two or more negative electrode active materials shared with any combination and ratio can be used Material.

In addition, as long as the effect of the present invention is not significantly impaired, then the partial size of negative electrode active material is arbitrary.However, examining Consider excellent battery behavior such as starting efficiency, multiplying power property, cycle characteristics etc., partial size is usually 1 μm or more, and preferably 15 μm More than, and typically about 50 μm hereinafter, preferably from about 30 μm or less.In addition, such as negative electrode active material be also used as it is following Carbonaceous material use, such as by being coated with the carbonaceous material with the organic substance of pitch etc. and then calcining the carbon Material and the material obtained, or amorphous carbon is formed on the surface by using CVD method etc. and the material that obtains.For applying The example of the organic substance of cloth includes the coal tar asphalt from maltha to pitch；The coal mink cell focus of destructive distillation liquefaction oil etc.；Often Press the straight run mink cell focus of Residual oil and decompression residuum etc.；Crude oil；The decomposition generated when crude oil, naphtha etc. thermally decompose as by-product The petroleum heavy oil of mink cell focus (for example, ethylene heavy ends) etc..By distilled at 200 DEG C to 400 DEG C these mink cell focuses and Then the residue for being crushed to 1 μm to 100 μm of size and obtaining also is used as the organic substance.In addition, vinyl chloride resin, phenol Urea formaldehyde, imide resin etc. also are used as the organic substance.

In an embodiment of the invention, cathode includes metal and/or metal oxide and carbon as negative electrode active Material.The example of the metal include Li, Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La and this Two or more alloys in a little.These metal or alloy can be used as two or more mixtures and use.In addition, these metals Or alloy can contain one or more nonmetalloids.

The example of the metal oxide include Si oxide, aluminum oxide, tin-oxide, indium oxide, zinc oxide, Oxidate for lithium and its compound.In the present embodiment, tin-oxide or Si oxide are preferably comprised as negative electrode active material Material, and further preferably Si oxide.This is because Si oxide is more stable and hardly causes and other compounds Reaction.In addition, for example one or more elements selected from nitrogen, boron and sulphur of 0.1 to 5 quality % can be added to the gold Belong in oxide.In this way it is possible to improve the electric conductivity of the metal oxide.In addition, use is all by vapor deposition etc. Metal or metal oxide as described in the coating of the conductive material of carbon, can similarly improve electric conductivity.

The example of the carbon includes graphite, amorphous carbon, diamond-like, carbon nanotube and its compound.High crystalline stone Ink have high conductivity, and relative to negative electrode current collector made of the metal such as copper adhesiveness and voltage it is flat Property aspect it is excellent.On the other hand, since the volume expansion of the low amorphous carbon of crystallinity is smaller, mitigate entire cathode The effect of volume expansion is high, and hardly occurs due to inhomogeneities deterioration as caused by grain boundary and defect.

The feature that there is the ability for receiving lithium to be much larger than carbon for the metal and the metal oxide.Therefore, by using The a large amount of metal and the metal oxide can improve the energy density of battery as negative electrode active material.For reality Existing high-energy density, the content of the metal and/or the metal oxide preferably in negative electrode active material is than high.It is relatively large The metal and/or the metal oxide be preferably as it increase cathode entirety capacity.The metal and/or Content of the metal oxide in cathode is preferably the 0.01 mass % or more of negative electrode active material, more preferably 0.1 matter Measure % or more, and further preferably 1 mass % or more.However, with carbon phase ratio, the metal and/or metal oxidation Object volume change when absorbing and releasing lithium is big, and may lost and electrically engage.Therefore, the metal in negative electrode active material And/or the amount of the metal oxide be 99 mass % hereinafter, preferably 90 mass % hereinafter, more preferably 80 mass % with Under.As described above, negative electrode active material is the material that can reversibly absorb and release lithium ion with charge and discharge in cathode, And do not include other adhesives etc..

For example, anode active material layer can be formed as pellet electrode by the above-mentioned negative electrode active material of rolling formation, Or pellet (pellet) electrode can be formed as by compression molding.However, in general, such as the case where anode active material layer Like that, anode active material layer can be formed by being coated on current-collector with dry coating liquid, wherein the coating fluid can With by by above-mentioned negative electrode active material, adhesive and as needed and the various auxiliary agent solvent pulps that contain and obtain.

Negative electrode binder is not particularly limited, but its example includes that polyvinylidene fluoride, vinylidene fluoride-hexafluoropropene are total Polymers, vinylidene fluoride-TFE copolymer, styrene-butadiene copolymer rubber, polytetrafluoroethylene (PTFE), polypropylene, poly- second Alkene, acrylic compounds, polyimides, polyamidoimide etc..It apart from the above, also may include styrene butadiene ribber (SBR) Deng.When using the aqueous binder of such as SBR emulsion, the thickener of carboxymethyl cellulose (CMC) etc. also can be used. From negative electrode active material from the viewpoint of balance between " enough adhesive strengths " and " high-energy ", relative to 100 mass parts Material, the amount of used negative electrode binder is preferably 0.5 to 20 mass parts.The negative electrode binder can be used in mixed way.

As the material of negative electrode current collector, well known material, such as the viewpoint from electrochemical stability can be arbitrarily used From the point of view of, it is preferable to use such as copper, nickel, stainless steel, aluminium, chromium, silver and its alloy metal material.Wherein, from workability and at From the viewpoint of this, particularly preferred copper.Further preferably negative electrode current collector also carries out surface roughening treatment in advance.In addition, current-collector Shape be also arbitrary, and its example includes foil-like, tabular and netted.Also perforation type current-collector can be used, such as Porous metal mesh or punch metal.

For example, can be by forming the negative electrode active containing negative electrode active material and negative electrode binder in negative electrode current collector Material layer makes cathode.The example of the forming method of anode active material layer includes scraper method, die slot rubbing method, CVD method, splashes Penetrate method etc..After being pre-formed anode active material layer, can be formed by the method for being vapor-deposited, sputtering etc. aluminium, The film of nickel or its alloy, to obtain negative electrode current collector.

In order to reduce impedance, conductive aid can be added in the coating containing negative electrode active material.Conduction auxiliary The example of material includes flakey, cigarette ash shape, fibrous carbonaceous particle etc., such as graphite, carbon black, acetylene black, vapor grown carbon Fiber (for example, the VGCF (registered trademark) manufactured by Showa electrician) etc..

[2] positive

Positive electrode refers to the electrode of hot side in battery.For example, anode comprising can with charge and discharge reversibly The positive electrode active materials of lithium ion are absorbed and released, and has and is layered in positive electrode active materials on current-collector with positive electrode binder Structure as anode active material layer.In an embodiment of the invention, positive unit area charging capacity is 3mAh/cm²More than, preferably 3.5mAh/cm²More than.From the point of view of the viewpoints such as safety, positive unit area charging capacity is excellent It is selected as 15mAh/cm²Below.Here, unit area charging capacity is calculated by the theoretical capacity of active material.That is, positive Unit area charging capacity calculated by (theoretical capacities of positive electrode active materials that anode uses)/(positive area). Note that the area of anode refers to a surface of anode rather than the area on two surfaces.

Positive electrode active materials in present embodiment are not particularly limited, as long as it is the material that can absorb and release lithium , and can be selected from several viewpoints.From the viewpoint of high-energy density, high capacity compound is preferably comprised. The example of high capacity compound includes lithium acid nickel (LiNiO₂) and by in another metallic element aliquot replacement lithium acid nickel Ni and the lithium nickel composite oxide obtained, and the laminated Li-Ni composite oxides preferably indicated by following formula (A).

Li_yNi_(1-x)M_xO₂ (A)

(condition be 0≤x < 1,0 < y≤1.2, and M be in the group being made of Co, Al, Mn, Fe, Ti and B at least A kind of element.)

From the viewpoint of high capacity, preferably Ni content is high, or that is, x is less than 0.5 in formula (A), and more preferably It is 0.4 or less.The example of such compound includes Li_αNi_βCo_γMn_δO₂(0 < α≤1.2, preferably 1≤α≤1.2, β+γ+δ= 1, β >=0.7, and γ≤0.2) and Li_αNi_βCo_γAl_δO₂(0<α≤1.2, preferably 1≤α≤1.2, β+γ+δ=1, β>=0.6, It is preferred that β >=0.7, γ≤0.2), in particular, LiNi_βCo_γMn_δO₂(0.75≤β≤0.85,0.05≤γ≤0.15,0.10≤δ ≤0.20).More specifically, for example can it is preferable to use LiNi_0.8Co_0.05Mn_0.15O₂、LiNi_0.8Co_0.1Mn_0.1O₂、 LiNi_0.8Co_0.15Al_0.05O₂And LiNi_0.8Co_0.1Al_0.1O₂。

From the viewpoint of thermal stability, further preferably Ni content is no more than 0.5, or that is, x is 0.5 in formula (A) More than.Further preferably specific transition metal is accounted for no more than half.The example of such compound includes Li_αNi_βCo_γMn_δO₂(0<α ≤ 1.2, preferably 1≤α≤1.2, β+γ+δ=1,0.2≤β≤0.5,0.1≤γ≤0.4,0.1≤δ≤0.4).More specifically Example includes LiNi_0.4Co_0.3Mn_0.3O₂(abbreviation NCM433), LiNi_1/3Co_1/3Mn_1/3O₂、LiNi_0.5Co_0.2Mn_0.3O₂(referred to as ) and LiNi NCM523_0.5Co_0.3Mn_0.2O₂(abbreviation NCM532) (condition is these compounds containing comprising wherein each transition metal Amount changes about 10% compound).

It is used in addition, the two or more compounds indicated by formula (A) can be used as mixture, and for example further preferably with 9: 1 to 1:9 range (representative instance 2:1) uses the mixture of NCM532 or NCM523 and NCM433.Moreover, by by formula (A) material of Ni content height (x is 0.4 or less) and Ni content are no more than the material of 0.5 (x is 0.5 or more, such as NCM433) in Mixing, can form the battery with high capacity and high thermal stability.

In addition to above-mentioned positive electrode active materials, example further includes the LiMn2O4 with layer structure or spinel structure, example Such as LiMnO₂、Li_xMn₂O₄(0<x<2)、Li₂MnO₃And Li_xMn_1.5Ni_0.5O₄(0<x<2)；LiCoO₂With by with other metal portions It splits and changes these transition metal and those of obtain；Stoichiometric composition based on these lithium transition-metal oxides has excess Li Those of；With with those of olivine structural, such as LiFePO₄.In addition it is also possible to using by with Al, Fe, P, Ti, Si, These metal oxides of the aliquot replacements such as Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La and the material obtained.On Stating one of positive electrode active materials can be used alone or two or more can be applied in combination.

The positive electrode binder similar with negative electrode binder can be used.Wherein, from the viewpoint of versatility and low cost, It is preferred that polyvinylidene fluoride or polytetrafluoroethylene (PTFE), more preferable polyvinylidene fluoride.From in " enough adhesive strengths " and " high energy From the viewpoint of balancing between amount ", relative to the positive electrode active materials of 100 mass parts, the amount of used positive electrode binder is excellent It is selected as 2 to 15 mass parts.

In order to reduce impedance, conductive aid can be added in the coating containing positive electrode active materials.Conduction auxiliary The example of material includes flakey, cigarette ash shape, fibrous carbonaceous particle etc., such as graphite, carbon black, acetylene black, vapor grown carbon Fiber (for example, the VGCF manufactured by Showa electrician) etc..

The anode current collector similar with negative electrode current collector can be used.Particularly as anode, using aluminium, aluminium alloy, Iron, nickel, chromium, molybdenum type stainless steel current-collector be preferred.

[3] insulating layer

(material and manufacturing method etc.)

It can be by applying layer of cloth paste compound to cover a part of active material layer of positive or negative pole and do It is dry and remove solvent and form insulating layer.Although insulating layer can be formed only in the one side of active material layer, by two Face, which forms insulating layer (especially as symmetrical structure), has the advantages that electrode warps can be reduced.

Insulating layer is the paste compound for being used to form porous dielectric layer with slurry.Therefore, " insulating layer " is referred to as " porous dielectric layer ".Adhesive (or binder) of the insulating layer with slurry comprising non-conductive particles and with specific composition, and And the non-conductive particles, described adhesive and optional compositions are evenly dispersed in solvent as solid component.

It is expected that non-conductive particles are stabilized and electrochemically stable under the use environment of lithium ion secondary battery.Make For non-conductive particles, various inorganic particulates, organic filler and other particles can be used for example.Wherein, preferred inorganic oxide Object particle or organic filler, in particular, more preferably using inorganic oxide grain from the viewpoint of the thermal stability height of particle Son.Metal ion in particle is formed about salt in electrode sometimes, this may cause the internal resistance increase of electrode and secondary cell Cycle characteristics reduces.Other described particles include and being surface-treated with surface of the non-conducting material to attritive powder Assign the particle of electric conductivity.The attritive powder can by conductive metal, compound and oxide for example carbon black, graphite, SnO₂, ITO and metal powder be made.Two or more above-mentioned particles can be applied in combination and as non-conductive particles.

The example of inorganic particulate includes such as aluminum oxide, Si oxide, magnesium oxide, titanium oxide, BaTiO₂、ZrO、 The inorganic oxide particle of alumina silica composite oxides etc.；The inorganic nitrogen of aln precipitation and boron nitride etc. Compound particle；The covalent crystal particle of silicon, diamond etc.；The slightly solubility ion of barium sulfate, calcirm-fluoride, barium fluoride etc. Crystal particles；The clay minuteness particle of such as talcum and montmorillonite.If it is necessary, these particles can carry out element substitution, table Surface treatment, solution treatment etc., and can be used alone or be applied in combination with two or more.Wherein, from the stabilization of electrolyte From the viewpoint of property and potential stability, preferred inorganic oxide particle.

The shape of non-conductive particles is not particularly limited, and can be spherical, needle-shaped, rodlike, fusiform, plate etc..From From the viewpoint of effectivelying prevent spicule to penetrate, the shape of the inorganic particulate can be plate.

When the shape of non-conductive particles is plate, preferably non-conductive particles are orientated in perforated membrane, so that its Flat surface is arranged essentially parallel to the surface of perforated membrane.By using such perforated membrane, it can preferably inhibit battery short circuit Occur.By the way that non-conductive particles are orientated as described above, it is contemplated that the non-conductive particles are configured in a part Overlap each other on flat surface, and the gap (through-hole) from a face of perforated membrane to another face be not straight line formed but (that is, curvature is than increasing) formed in curved shape.Speculate that this is that Li dendrite penetrates perforated membrane and preferably presses down in order to prevent Make the generation of short circuit.

It is preferable to use plate non-conductive particles, especially inorganic particulate example include various commercial product, such as " SUNLOVELY " (SiO of AGC Si-Tech Co., Ltd manufacture₂), stone originates in the pulverized product " NST-B 1 " of industry company manufacture (TiO₂), the plate barium sulfate " H series " of Sakai chemical industrial company manufacture, " HL series ", " Micron of Lin Huacheng company manufacture White " (talcum), " Benger " (bentonite) of the manufacture of Lin Huacheng company, " BMM " and " BMT " of the manufacture of He He lime company (boehmite), " Serasur BMT-B " [aluminium oxide (Al of He He lime company manufacture₂O₃)], Kinsei Matec Co., Ltd " Serath " (aluminium oxide) of manufacture, " AKP series " (aluminium oxide) and Fei Chuan mining company system of sumitomo chemical company manufacture " Hikawa Mica Z-20 " (sericite) made.In addition, SiO₂、Al₂O₃Japanese Unexamined Patent Publication 2003-206475 can be passed through with ZrO The production of method disclosed in number bulletin.

When the shape of non-conductive particles be it is spherical when, the average grain diameter of non-conductive particles preferably 0.1 μm to 10 μm, In the range of more preferably 0.4 μm to 5 μm, particularly preferably 0.5 μm to 2 μm.When the average grain diameter of non-conductive particles is upper When stating in range, it is easy to control the dispersity of perforated membrane slurry, thus easily fabricated porous with uniform predetermined thickness Film.In addition, such average grain diameter provides the advantage that.The adhesiveness to adhesive is improved, and even if more winding When pore membrane, it is also possible to prevent non-conductive particles peeling, enough safeties as a result may be implemented perforated membrane is thinning. Since the increase of the particle-filled rate in perforated membrane can be inhibited, the drop of the ionic conductivity in perforated membrane can be inhibited It is low.Furthermore, it is possible to which thin perforated membrane is made.

The average grain diameter of non-conductive particles can be by appointing in any visual field from SEM (scanning electron microscope) image Meaning selection 50 primary particles, carry out image analysis and obtain each particle equivalent circle diameter average value and obtain.

The particle diameter distribution (CV value) of non-conductive particles is preferably 0.5 to 40%, and more preferably 0.5 to 30%, it is especially excellent It is selected as 0.5 to 20%.By the way that the particle diameter distribution setting of non-conductive particles within the above range, can be kept non-conductive grain Predetermined gap between son, so as to inhibit since resistance increases caused by hindering lithium mobile.The grain of non-conductive particles Diameter is distributed (CV value) can be by the partial size with electron microscope observation non-conductive particles, measurement 200 or more particle, determination The standard deviation of average grain diameter and partial size and (standard deviation of partial size)/(average grain diameter) is calculated to determine.The bigger meaning of CV value Change of size it is bigger.

When insulating layer solvent contained in slurry is nonaqueous solvents, the polymer that is dispersed or dissolved in nonaqueous solvents It can be used as adhesive.As the polymer being dispersed or dissolved in nonaqueous solvents, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE) (PTFE), polyhexafluoropropylene (PHFP), polytrifluorochloroethylene (PCTFE), poly- perfluoro alkoxy vinyl fluoride, polyimides, polyamides Amine acid imide etc. may be used as adhesive, and without being limited thereto.

Alternatively, it is also possible to use the adhesive for bonding active material layer.

When insulating layer solvent contained in slurry is that aqueous solvent (using water or contains water as the mixing of main component Solution of the solvent as the decentralized medium of adhesive) when, the polymer conduct being dispersed or dissolved in aqueous solvent can be used Adhesive.The polymer in aqueous solvent is dispersed or dissolved in including, for example, acrylic resin.It is excellent as acrylic resin Choosing is used by polymerizeing such as acrylic acid, methacrylic acid, acrylamide, Methacrylamide, acrylic acid 2- hydroxyl ethyl ester, methyl The monomer of acrylic acid 2- hydroxyl ethyl ester, methyl methacrylate, ethylhexyl acrylate, butyl acrylate etc. and the homopolymerization obtained Object.Acrylic resin can be the copolymer obtained by polymerizeing two or more above-mentioned monomers.In addition, two or more The homopolymer and the copolymer can mix.In addition to above-mentioned acrylic resin, such as styrene fourth can also be used The polyolefin resin of diene rubber (SBR) and polyethylene (PE), polytetrafluoroethylene (PTFE) (PTFE) etc..These polymer can individually make With or with being used in combination.Wherein, it is preferable to use acrylic resin.The form of adhesive is not particularly limited, grain The particle of sub- shape (powdered) can be used as it is, or the adhesive that can be used with solution state or emulsion state preparation. Two or more adhesives can use in different forms.

If it is necessary, insulating layer can contain the material other than above-mentioned conductive fillers and adhesive.Such material Example include the aftermentioned thickener for playing the role of insulating layer slurry various polymer materials.In particular, when making When with aqueous solvent, the polymer for playing the role of thickener is preferably comprised.As the polymer for playing the role of thickener, preferably make With carboxymethyl cellulose (CMC) or methylcellulose (MC).

Although being not particularly limited, conductive fillers to the ratio of entire insulating layer be suitably about 70 mass % with Upper (for example, 70 mass % to 99 mass %), preferably 80 mass % or more (for example, 80 mass % to 99 mass %), especially Preferably from about 90 mass % to 95 mass %.

The ratio of adhesive is suitably about 1 to 30 quality % hereinafter, preferably 5 to 20 quality % or less in insulating layer. In the case where containing the insulating layer forming component in addition to inorganic filler and adhesive, such as thickener, the content of thickener Than being preferably from about 10 mass % hereinafter, even more preferably about 7 mass % or less.If the ratio of adhesive is too small, insulating layer sheet The intensity (conformality) of body and the adhesiveness of active material layer is reduced, this may cause the defect of rupture and removing etc.. If the ratio of adhesive is too big, the gap between the particle of insulating layer becomes insufficient, and can reduce in some cases Ion permeability in insulating layer.

In order to maintain ionic conductivity, the porosity (voidage) (ratio of the pore volume to apparent volume) of insulating layer is excellent It is selected as 20% or more, more preferably 30% or more.However, if porosity is too high, due to be applied to insulating layer friction or It impacts and falling off or rupturing for insulating layer occurs, therefore porosity is preferably 80% hereinafter, more preferably 70% or less.

Porosity can be calculated by the ratio, true specific gravity and coating layer thickness for constituting the material of insulating layer.

When being D (μm) by a μm average grain diameter for the non-conductive particles indicated and when the porosity of insulating layer is P, by D The porosity index that × P is indicated is 0.4 or less.The partial size of non-conductive particles is smaller, dendrite and particle during dendritic growth The frequency of contact is higher, and some dendrite contact horizontally bifurcated or in the opposite direction bifurcated with each.As a result, suppression Growth of the dendrite on the stacking direction of insulating layer is made.In addition, will have identical from the viewpoint of the porosity of insulating layer Dendritic growth between the insulating layer of the non-conductive particles of partial size is compared, and porosity is smaller, the branch during dendritic growth The frequency of crystalline substance contact particle is higher.As a result, as described above, it is suppressed that growth of the dendrite on the stacking direction of insulating layer.

As described above, the partial size of non-conductive particles and the porosity of insulating layer greatly influence the direction of growth of dendrite. Therefore, it may be used as inhibiting by value obtained that the average grain diameter D of non-conductive particles is multiplied with the porosity P of insulating layer The index that dendrite is grown on the stacking direction of insulating layer.As the present inventor research as a result it has been found that pass through so that The mode of D × P≤0.4 configures non-conductive particles in a insulating layer, can effectively inhibit the stacking direction in insulating layer On dendritic growth.So as to effectively inhibit the internal short-circuit during battery charging.

(formation of insulating layer)

The method that description is formed into insulating layer.As the material for being used to form insulating layer, can be used conductive fillers, Pastes obtained by adhesive and solvent mix and disperse (comprising slurry form or black form, below equally applicable).

Solvent for insulating layer slurry includes the mixed solvent of water or primary aqueous.As the such mixed solvent of composition Water other than solvent, can suitably select and use can be (lower alcohol, low with the mixed uniformly one or more organic solvents of water Grade ketone etc.).Alternatively, the organic solvent can be such as N-Methyl pyrrolidone (NMP), pyrrolidones, methyl ethyl ketone, first The organic solvent of base isobutyl ketone, cyclohexanone, toluene, dimethylformamide, dimethyl acetamide etc. or its two or more group It closes.Insulating layer is not particularly limited with the solvent content in slurry, 40 to 90 quality % of preferably whole coating materials, especially Preferably from about 50 to 70 quality %.

The operation that conductive fillers and adhesive solvent are mixed can be by using suitable kneader such as ball Grinding machine, Disper Mill (registered trademark), Clearmix (registered trademark), Filmix (registered trademark), surpasses evenly dispersed machine Sound wave dispersion machine carries out.

For applying the operation of layer of cloth slurry, conventional general coating means can be used without limiting.For example, It can be by by means of appropriate coating device (gravure coater, slit coater, die coating machine, comma coating machine, dip-coating Machine etc.) it is coated with uniform thickness to be coated with the insulating layer slurry of predetermined amount.

It later, can be molten in insulating layer slurry by being removed by means of drying means dry coating material appropriate Agent.

(thickness)

The thickness of insulating layer is preferably 1 μm or more and 30 μm hereinafter, more preferably 2 μm or more and 15 μm or less.

[4] electrolyte

Electrolyte includes but is not particularly limited to stable nonaqueous electrolytic solution under the operating potential of battery.Nonaqueous electrolytic solution Specific example includes aprotic organic solvent, such as such as propylene carbonate (PC), ethylene carbonate (EC), fluoro carbonic acid Asia second Ester (FEC), bis- fluoroethylene carbonate of t- (t-DFEC), butylene carbonate (BC), vinylene carbonate (VC), ethylene carbonate base The cyclic carbonates of ethyl (VEC) etc.；Such as allyl methyl esters (AMC), dimethyl carbonate (DMC), carbonic acid diethyl The linear carbonate class of ester (DEC), ethyl methyl carbonate (EMC), dipropyl carbonate (DPC) etc.；Polypropylene carbonate ester derivant；Such as The aliphatic carboxylic acid esters of methyl formate, methyl acetate, ethyl propionate etc.；The cyclic annular esters of gamma-butyrolacton (GBL) etc..It is non- Water electrolysis liquid can be used alone, or two or more mixtures can be applied in combination.In addition it is possible to use such as ring fourth The sulphur-containing cyclic compound of sulfone, fluorination sulfolane, propane sultone or propene sultone etc..

The specific example of salt is supported to include but be not particularly limited to such as LiPF contained in electrolyte₆、LiAsF₆、 LiAlCl₄、LiClO₄、LiBF₄、LiSbF₆、LiCF₃SO₃、LiC₄F₉SO₃、Li(CF₃SO₂)₂、LiN(CF₃SO₂)₂Lithium salts.It supports Salt, which can be used alone, or its is two or more to be applied in combination.

[5] diaphragm

When cell device 10 includes diaphragm 13 between anode 11 and cathode 12, the diaphragm is not particularly limited, and And it can be used by such as polyethylene terephthalate (PET), polypropylene, polyethylene, fluorine resin, polyamide, polyamides Imines, polyester, perforated membrane or non-woven fabrics made of polyphenylene sulfide and wherein such as silica, aluminium oxide, glass it is inorganic Substance adheres to or the product that is adhered on the substrate made of above-mentioned material and is individually processed into non-woven fabrics or cloth by above-mentioned material Product as diaphragm.The thickness of diaphragm can be arbitrary.However, thin membrane is excellent from the viewpoint of high-energy density Select and thickness can be such as 10 μm to 30 μm.

From the viewpoint of the effect for giving full play to insulating layer, diaphragm 13 is constructed such that the percent thermal shrinkage at 200 DEG C Less than 5%, and Ge Erlai value (Gurley value) is 10 seconds/100ml or less.By using percent thermal shrinkage pole at high temperature Low diaphragm can inhibit damage of the diaphragm to insulating layer, such as described above at a high temperature of battery due to the contraction of diaphragm Insulating layer is removed from active material layer with being pulled by diaphragm.

On the other hand, the small diaphragm 13 of percent thermal shrinkage generally has low Ge Erlai value, and the diaphragm small when percent thermal shrinkage 13 for insulation between electrode when, exist since the growth for the metallic dendrite being precipitated during charging leads to small internal short-circuit And prevent a possibility that battery is from charging.In order to prevent this situation, it is contemplated that using thick diaphragm 13, but when using thickness Diaphragm 13 when, the distance between electrode becomes larger, and energy density reduce.Therefore, by being formed with insulating layer on the surface Electrode between configuration 200 DEG C at percent thermal shrinkage less than 5% and Ge Erlai value be 10 seconds/100ml diaphragm below, Ke Yichong Distribution waves the effect of insulating layer itself without will lead to energy density reduction.

Material it is preferable to use PET as diaphragm 13 from the point of view.The form of diaphragm 13 is preferably nonwoven Cloth.

Ge Erlai value is index related with the gas permeability of woven fabric and non-woven fabrics, and is measured according to JIS P8117 Value.Ge Erlai value is higher, and expression gas permeability is lower.In general, having positive and negative for preventing compared with the diaphragm of Gao Geerlai value Short circuit between pole, and the value is 100 seconds/100ml or more.

The present invention is not limited to above-mentioned lithium ion secondary batteries, and are applicable to any battery.However, due in many feelings Problem hot frequent occurrence in high-capacity battery under condition, so present invention is preferably applicable to the battery of high capacity, especially lithium Ion secondary battery.

Next, by the embodiment for the manufacturing method for describing electrode shown in Fig. 3.In the following description, positive 11 Hes Cathode 12 will be described as " electrode " without being particularly distinguished from each other, but anode 11 and cathode only the material used, Shape etc. difference, and explanation is suitable for both anode 11 and cathode 12 below.

The manufacturing method of electrode is not particularly limited, as long as electrode can be formed to have active material layer 111 and insulation The structure that layer 112 is finally laminated on current-collector 110 with this sequence.

Active material and adhesive dispersion can be formed into active material layer prepared by slurry in a solvent by being coated with With mixture, and the active material layer being coated with is dry with mixture, and form active material layer 111.By active material After layer mixture drying, the method can also include the step for the active material layer mixture compression molding that will be dried Suddenly.Insulating layer 12 can also be formed by process identical with active material layer 111.That is, can will be insulated by coating Material and adhesive dispersion form slurry and the insulating layer mixture for preparing in a solvent, and dry be coated with insulating layer is used Mixture, and form insulating layer 112.After by insulating layer mixture drying, the method can also include that will dry The step of insulating layer mixture compression molding.

The formation process of above-mentioned active material layer 111 and the formation process of insulating layer 112 can individually be implemented or with appropriate Combination implement.The formation process of combined activity material layer 111 and the formation process of insulating layer 112 are including, for example, following journey Sequence: before the active material layer that will be coated on current-collector 110 is dry with mixture, insulating layer is coated on mixture and has been applied On the active material layer mixture of cloth, and active material layer mixture and insulating layer is whole dry simultaneously with mixture； It is being coated with and after dried active material layer mixture, is carrying out the coating and drying of insulating layer mixture on it, and will Active material layer mixture and the insulating layer whole compression forming simultaneously of mixture.Pass through the shape of combined activity material layer 111 At the formation process of process and insulating layer 112, the manufacturing process of electrode can simplify.

Next, by the example for the manufacturing method for describing secondary cell.

Firstly, preparing anode and cathode, and prepare diaphragm.Anode and cathode be respectively provided with current-collector and current-collector extremely The active material layer formed on a few surface, and at least one of anode and cathode are also included in the active material layer The insulating layer formed on surface.In addition, insulating layer is the porous dielectric layer containing multiple particles, and it is constructed such that by grain The porosity index that the average grain diameter of son × porosity indicates is 0.4 or less.

Then, anode and cathode are configured to facing with each other to be constituted cell device in such a way that diaphragm is placed in therebetween. When anode and cathode number are greater than 1, anode and cathode are arranged so that anode and cathode are alternately facing with each other, and also standard The diaphragm of quantity necessary to standby configuration between a positive electrode and a negative electrode.By diaphragm configuration between a positive electrode and a negative electrode so that anode It is not directly opposite each other with cathode.

Next, cell device is encapsulated into shell together with electrolyte, secondary cell is thus manufactured.

Although describing the present invention by reference to an embodiment, the present invention is not limited to the above embodiments, and And it can arbitrarily change in the range of technical concept of the invention.

For example, in the above-described embodiment, describe active material layer 111 and insulating layer 112 being applied to current-collector 110 One side on situation.However, by being coated with 111 He of active material layer in a similar way on the another side of current-collector 110 Insulating layer 112 can manufacture and all have the electrode of active material layer 111 and insulating layer 112 on the two sides of current-collector 110.

In addition, the battery obtained through the invention can be used for various uses.Some examples are described below.

[battery pack]

Multiple batteries can combine to form battery pack.For example, battery pack can have two of wherein present embodiment with Upper construction battery series connection and/or be connected in parallel.Battery can be properly selected according to the target voltage and capacity of battery pack Serial number and number in parallel.

[vehicle]

Above-mentioned battery or its battery pack can be used for vehicle.It includes mixed that the example of the vehicle of battery or assembled battery, which can be used, Close power car, fuel-cell vehicle and electric vehicle (four-wheel car (commercial vehicle of car, truck and bus etc., And Light-duty Vehicle etc.), motorcycle (two wheeler and tricycle).Note that the vehicle of present embodiment is not limited to automobile, and described Battery is also used as the various power supplys of other vehicles such as means of transport of such as electric train.Example as such vehicle Son, Fig. 6 show the schematic diagram of electric vehicle.Electric vehicle 200 shown in Fig. 6 has battery pack 210, the battery pack quilt It is configured to connect and be connected in parallel to meet required voltage and capacity by multiple above-mentioned batteries.

[electrical storage device]

Above-mentioned battery or its battery pack can be used for electrical storage device.Use the secondary cell or the electrical storage device of its battery pack Example include be connected between the loads such as the source power supply for being supplied to average family and household electrical appliance with have a power failure when use Make backup power source or accessory power supply electrical storage device and for extensive electric power store so that due to such as photovoltaic power generation can The renewable sources of energy lead to the electrical storage device for changing big electric power output stabilization at any time.It is schematically showed in Fig. 7 such The example of electrical storage device.Electrical storage device 300 shown in Fig. 7 has battery pack 310, and the battery pack 310 is configured to by more A above-mentioned battery connects and is connected in parallel and meets required voltage and capacity.

[other]

In addition, above-mentioned battery or its battery pack can be used as the electricity of the mobile device of mobile phone, laptop etc. Source.

The present invention will be described by specific embodiment now.However, the present invention is not limited to following embodiments.

<manufacture of secondary cell>