CN101667663B

CN101667663B - Nonaqueous secondary battery and apparatus using the same

Info

Publication number: CN101667663B
Application number: CN2008102153379A
Authority: CN
Inventors: 占部浩儿; 喜多房次
Original assignee: Hitachi Maxell Ltd
Current assignee: Maxell Holdings Ltd
Priority date: 2007-10-10
Filing date: 2008-09-05
Publication date: 2013-05-15
Anticipated expiration: 2028-09-05
Also published as: JP2009110942A; CN101667663A

Abstract

The invention provides a nonaqueous secondary battery, which has the advantages of high capacity, excellent and safe charge-discharge circle characteristic and high-reliability. The nonaqueous secondary battery provided by the invention, has an anode, a cathode and a nonaqueous electrolyte, wherein, the anode has an anode composition layer containing anode active substance, which is characterized is that: the anode active substance contains lithium-containing transition metal oxide with laminar crystal morphology is used as the oxide active substance, and metallic element containing lithium transition metal oxide is formed, at least one element from the group of Co, Ni and Mn and Li are selected as the main body, moveover, at least one element is selected from the group constituted of Mg, Ti, Zr, Ge, Nb, Al and Sn, The density of the anode composition layer is more than 3.5g/cm<3>, and the nonaqueous electrolyte contains aromatic compound of alkoxyl, and the alkoxyl has a alkyl of a straight-chain or a branched chain whose carbon atomic number is 1-4.

Description

Non-aqueous secondary batteries and use its equipment

Technical field

The present invention relates to the high non-aqueous secondary batteries of reliability such as high power capacity, excellent charge/discharge cycle characteristics, fail safe.

Background technology

In recent years, secondary cell is as the power supply of PC, mobile phone etc., or stores the power supply of use as electric automobile or electric power, becomes one of indispensable important composed component.

Especially, in portable computer, this mobile communication purposes of portable information terminal (Personal Digital Assistant), constantly require more miniaturization, lightweight.But because of the backlight of display panels or to describe to control the electric power capacity high, secondary cell consumed also insufficient in present stage, therefore, current situation is compression, the lightweight that is difficult to the system that realizes.Especially with regard to PC, along with formed multifunctions such as lift-launch DVD (digital versatile disc), and there is the tendency that power consumption increases.Therefore, increase power capacity, the voltage that particularly increases monocell is that the above discharge capacity of 3.3V is the task of top priority always.

In addition, along with the intensification of earth environment problem, the electric automobile that does not produce tail gas, noise allows the people give more sustained attention.Recently, it is that the regenerated energy in when brake is stored in battery and effectively utilizes that system is arranged, or with the electric energy that is stored in battery, raises the efficiency etc. when starting, and adopts the parallel hybrid power electric automobile (HEV) of such system more and more welcome.But the power capacity of the battery of present stage is low, therefore, the quantity that must increase battery obtains voltage, and for this reason, the generation interior space is narrow and small, the problems such as bad stability of car body.

In secondary cell, use the lithium secondary battery of nonaqueous electrolytic solution, because voltage is high and lightweight, can expect high-energy-density, therefore receive publicity.Particularly with at the disclosed LiCoO of patent documentation 1 ₂for the lithium-containing transition metal oxide of representative, as positive active material, the lithium secondary battery that the lithium metal of usining is used as negative electrode active material, due to the electromotive force had more than 4V, therefore can expect to realize high-energy-density.

But, present by LiCoO ₂liCoO as material with carbon elements such as positive active material, graphite as negative electrode active material ₂be secondary cell, its end of charge voltage is generally below 4.2V, under this charge condition, only reaches LiCoO ₂the charge volume of about 6 one-tenth of theoretical capacity.By making end of charge voltage higher than 4.2V, the capacity that can increase electric power, but along with the increase of charge volume, LiCoO ₂crystal structure damage and shorten charge and discharge circulation life or LiCoO ₂the crystal structure deficient in stability, therefore, produce the problems such as thermal stability reduction.

In order to address this problem, and repeatedly carry out to LiCoO ₂the trial of middle interpolation dissimilar metal element (patent documentation 2～5).

In addition, also repeatedly carry out the trial (patent documentation 6～8) of the high-voltage region use battery more than 4.2V.

From now on, for secondary cell, except above before this high capacity, also require to comprise the high reliability of in the past above fail safe.Usually, by the active material increased in electrode, contain ratio, or improve electrode density, especially anode mixture layer density, can significantly improve battery capacity, still, on the other hand, the problem that such high capacity method exists the fail safe of battery to reduce gradually.

Therefore, in order to adapt to the requirement of high power capacity, expect such battery: use the stable material of crystal structure, even this material is than LiCoO ₂high electromotive force (voltage regime), but also safety and invertibity are discharged and recharged well, even and carry out the densification of anode mixture layer, also can guarantee fail safe in the past, also meet reliabilities such as not producing cell expansion.

In addition, LiCoO in the past ₂the positive electrode active material electrolyte cell, if make final discharging voltage higher than 3.2V,, because the current potential discharged latter stage reduces large and can not discharge fully, reduce the discharge electricity amount efficiency with respect to charging significantly.And, owing to not discharging fully, so LiCoO ₂crystal structure easily damage, charge and discharge circulation life shortens.This phenomenon is more remarkable in above-mentioned high-pressure area.

In addition, final voltage while making full charging is the above charge condition of 4.2V, except the caused charge and discharge circulation life of the damage of the crystal structure because of positive active material and thermal stability reduction, increase due to the active site of positive active material, and make electrolyte (solvent) oxidation Decomposition, form passivating film on anodal surface, increase internal resistance and make the part throttle characteristics variation.In addition, when the charging voltage of battery is high, if the battery after charging for example is positioned under 150 ℃ of such hot environments, due to the reaction of anodal and electrolyte, may make the battery temperature rising.

As the technology of the caused problem of reaction that solves above-mentioned such positive pole and electrolyte, for example, having the people to contain methyl phenyl ethers anisole in having proposed to make electrolyte in patent documentation 9 is additive.This technology is characterised in that, reciprocal reaction (shuttle reaction) by the additive under the current potential higher than charging potential, improve charge/discharge cycle characteristics, thermal runaway during overcharging in the time of can suppressing the charging under large electric current, discharge capacitance after 90 ℃ of preservations is high, the harmful effect that does not have additive to produce.But, about improving at 150 ℃ or than the storage stability under the environment of its high temperature, do not have any open.

Patent documentation 1: Japanese kokai publication sho 55-136131 communique

Patent documentation 2: Japanese kokai publication hei 04-171659 communique

Patent documentation 3: Japanese kokai publication hei 03-201368 communique

Patent documentation 4: Japanese kokai publication hei 07-176202 communique

Patent documentation 5: TOHKEMY 2001-167763 communique

Patent documentation 6: TOHKEMY 2004-296098 communique

Patent documentation 7: TOHKEMY 2001-176511 communique

Patent documentation 8: TOHKEMY 2002-270238 communique

Patent documentation 9: Japanese kokai publication hei 09-050822 communique

Summary of the invention

The present invention is the invention In view of the foregoing completed, and its purpose is to provide the high non-aqueous secondary batteries of reliability such as a kind of high power capacity, excellent charge/discharge cycle characteristics and fail safe.

To achieve these goals, non-aqueous secondary batteries of the present invention is for possessing positive pole, the non-aqueous secondary batteries of negative pole and nonaqueous electrolyte, wherein just have an anode mixture layer that contains positive active material, it is characterized in that, as above-mentioned positive active material, the lithium-containing transition metal oxide that contains the crystal structure with stratiform, form the metallic element of above-mentioned lithium-containing transition metal oxide, with from Co, at least one element and the Li that in the group that Ni and Mn form, select are main body, and, contain from Mg, Ti, Zr, Ge, Nb, at least one element of selecting in the group that Al and Sn form, the density of above-mentioned anode mixture layer is 3.5g/cm ³above, above-mentioned nonaqueous electrolyte contains the aromatic compound with alkoxyl, and described alkoxyl has the alkyl of the straight or branched of carbon number 1～4.

Non-aqueous secondary batteries of the present invention, the density that makes anodal anode mixture layer is 3.5g/cm ³above, improve the loading of the positive active material in the anode mixture layer, simultaneously, stability in charged state under high voltage is high, lithium-containing transition metal oxide that contain specific metallic element is for positive active material, thereby make the charging under high voltage become possibility, realize like this high capacity.

In addition, as mentioned above, the positive active material that non-aqueous secondary batteries of the present invention relates to, have excellent stability, so, even repeatedly carry out damage that discharging and recharging of battery also can suppress positive active material etc.Like this, non-aqueous secondary batteries of the present invention has been guaranteed excellent charge/discharge cycle characteristics.

In addition, non-aqueous secondary batteries of the present invention, contain the above-mentioned aromatic compound with alkoxyl in nonaqueous electrolyte, these aromatic compounds, act on anodal surface and prevent that positive pole from contacting with the direct of nonaqueous electrolyte, simultaneously, the function of the cell voltage (open circuit voltage of battery) while having the storage of the battery that reduces charged state, can suppress the reaction of anodal and nonaqueous electrolyte by these functions.Thereby, non-aqueous secondary batteries of the present invention, by above-mentioned aromatic compound is produced to the anodal and inhibitory action non-aqueous solution electrolysis qualitative response, the effect produced with the high positive active material of stability in use is stacked Calais's performance effect, can improve the reliabilities such as fail safe of battery.

According to the present invention, can provide the high non-aqueous secondary batteries of reliability such as a kind of high power capacity, excellent charge/discharge cycle characteristics and fail safe.Non-aqueous secondary batteries of the present invention, for example, make positive electrode potential is that the such high-voltage charging of 4.35～4.6V becomes possibility under Li (lithium) reference potential, can be for requiring the purposes of higher output.

The accompanying drawing explanation

Fig. 1 is the figure that schematically means an example of non-aqueous secondary batteries of the present invention, and Fig. 1 (a) is its plane graph, and Fig. 1 (b) is its partial cross section figure.

Fig. 2 is the oblique view of the non-aqueous secondary batteries shown in Fig. 1.

Symbol description

1 positive pole

2 negative poles

3 barrier films

Embodiment

The formation that non-aqueous secondary batteries of the present invention has is: for example, to there is the positive pole of anode mixture layer and negative pole and carry out the overlapping and electrode body stepped construction that forms across barrier film, or it further is wound into to electrode body of spiral winding-structure etc., together with nonaqueous electrolyte, enclose in exterior body.

With regard to non-aqueous secondary batteries of the present invention, as nonaqueous electrolyte, for example, from the angle of electrical characteristic and ease for operation, consider, preferably use the non-aqueous solvent electrolyte that dissolves the electrolytic salts such as lithium salts in the non-water solvents such as organic solvent, but, even polymer dielectric, gel electrolyte use also out of question.

As the solvent of nonaqueous electrolytic solution, there is no particular restriction, such as enumerating the chain esters such as dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methylpropyl carbonate (メチ Le プロピオ Application カ-ボネ-ト), the high cyclic esters of dielectric constant such as ethylene carbonate, propene carbonate, butylene, vinylene carbonate, the mixed solvents of chain ester and cyclic ester etc., the chain ester of take is that be main solvent suitable especially with mixed solvent cyclic ester.

In addition, as solvent, except above-mentioned ester, can also use such as chain phosphotriesters, 1 such as trimethyl phosphates, 2-dimethoxy-ethane, 1, the ethers such as 3-dioxa penta ring, oxolane, 2-methyl-oxolane, Anaesthetie Ether, nitrile, two nitriles, isocyanates, Halogen solvent etc.In addition, also can use amine system or imines is that the sulphur such as organic solvent or sulfolane are organic solvent etc.

When preparing nonaqueous electrolytic solution, as the electrolytic salt that is dissolved in solvent, can enumerate for example LiClO ₄, LiPF ₆, LiBF ₄, LiAsF ₆, LiSbF ₆, LiCF ₃sO ₃, LiC ₄f ₉sO ₃, LiCF ₃cO ₂, Li ₂c ₂f ₄(SO ₃) ₂, LiN (RfSO ₂) (Rf ' SO ₂), LiC (RfSO ₂) ₃, LiC _nf _2n+1sO ₃(n>=2), LiN (RfOSO ₂) ₂deng, wherein, Rf and Rf ' they are fluoroalkyls, they can distinguish use separately, also can be used together two or more.In above-mentioned electrolytic salt, the fluorine-containing organic lithium salt of carbon number more than 2 particularly preferably.Because the anionic property of above-mentioned fluorine-containing organic lithium salt is large, and easily be dissolved in above-mentioned solvent because of easy ion isolation.There is no particular restriction for the concentration of the electrolytic salt in nonaqueous electrolytic solution, for example, more than being preferably 0.3mol/l, more preferably, more than 0.4mol/l, is preferably below 1.7mol/l, more preferably below 1.5mol/l.

The nonaqueous electrolytic solution the present invention relates to (nonaqueous electrolyte) is characterised in that, contains the above-mentioned aromatic compound with alkoxyl.

Above-mentioned aromatic compound, have in battery charging process (particularly in the initial stage charging) and, in the function of the surface of positive active material formation surface protection film, by described surface protection film, can suppress anodal and contact with the direct of nonaqueous electrolyte.In addition, above-mentioned aromatic compound, while storing the battery of charged state under high temperature for example, have the effect of the open circuit voltage that reduces gradually battery.Therefore; battery of the present invention with the nonaqueous electrolyte that contains above-mentioned aromatic compound; in charged state; even for example store under the high temperature of 150 ℃ of left and right, also can utilize above-mentioned surface protection film to suppress anodal and contact with the direct of nonaqueous electrolyte, and reduce cell voltage; by these two kinds of effects; can suppress reacting of anodal and nonaqueous electrolyte, therefore can suppress because of the caused battery temperature rising of described reaction, excellent in safety.

Alkoxyl in the application's the aromatic compound with alkoxyl has the alkyl of the straight or branched of carbon number 1～4, can enumerate as such aromatic compound with alkoxyl the compound that there is above-mentioned alkoxyl on the aromatic rings such as phenyl ring or naphthalene nucleus, such as having methyl phenyl ethers anisole, ethoxybenzene, propoxyl group benzene, butyl phenyl ether, isopropoxy benzene, isobutyl phenyl ether, tert-butoxy benzene etc. to possess the aromatic compound of the alkoxyl of the straight or branched with carbon number 1～4; Or the derivative of the methyl phenyl ethers anisole such as methylanisole, dimethylanisole, ethylo benzene methyl ether, Methylethyl methyl phenyl ethers anisole, diethylbenzene methyl ether, dimethoxy benzene, ethoxybenzene methyl ether, fluoroanisole.When the above-mentioned alkyl with aromatic compound of alkoxyl has side chain, can improve the safety improvement effect, therefore further preferably, consider from this point, preferably alkoxyl has the aromatic compound with alkoxyl of branched alkyl, particularly preferably has the methyl phenyl ethers anisole of the tert-butyl group.Tert-butyl benzene methyl ether most preferably.

The above-mentioned aromatic compound with alkoxyl, can distinguish separately and use, and also can be used together two or more the use.

The above-mentioned addition with aromatic compound of alkoxyl, the angle of the effect produced from the interpolation of more effectively bringing into play by these aromatic compounds is considered, in the nonaqueous electrolytic solution total amount, more than being preferably 0.02 quality %, more preferably more than 0.05 quality %, more preferably more than 0.1 quality %.But, if the addition of above-claimed cpd is too much, the lower voltage of battery may be excessive, so the addition of these compounds, in the nonaqueous electrolytic solution total amount, be preferably below 3 quality %, more preferably, below 1 quality %, most preferably be below 0.5 quality %.

In addition, in nonaqueous electrolytic solution (nonaqueous electrolyte), also can contain above-claimed cpd additive in addition.As such additive, can enumerate the aromatic compound of nonionic.Particularly, can the illustration cyclohexyl benzene, cumene, tert-butyl benzene, tert-amyl benzene, octyl group benzene,toluene,xylene etc. such on aromatic rings in conjunction with the compound of alkyl, the halogen-containing compound of knot on aromatic rings that fluorobenzene, difluorobenzene, trifluoro-benzene, chlorobenzene, fluoroanisole etc. are such, the aromatic carbonates such as phthalic acid ester (dibutyl phthalate, dioctyl phthalate etc.), benzoic ether, methyl benzol carbonate, butyl phenyl carbonic ester, diphenyl carbonate etc. have the carbonic ester of phenyl, phenyl propionate, biphenyl etc.Wherein, preferably use in conjunction with the compound of alkyl, is particularly preferably used cyclohexyl benzene on aromatic rings.

These are also can on the active material surface of negative or positive electrode, form the compound of tunicle in battery without the aromatic compound of alkoxyl.These aromatic compounds can only be used separately a kind of, but also can and bring into play more excellent effect with two or more, especially, by will be on aromatic rings in conjunction with the compound of alkyl, the aromatic compounds such as biphenyl oxidized with the current potential lower than it carries out and use, can aspect the fail safe that improve battery, obtain desirable especially effect.

As the appropriate level of the aromatic compound that does not there is above-mentioned alkoxyl in nonaqueous electrolytic solution, for example, more than being thought of as 4 quality % from the angle of fail safe, from the angle of part throttle characteristics, be thought of as below 10 quality %.And during with two or more aromatic compound, its total amount is so long as get final product in above-mentioned scope, especially, by on aromatic rings, in conjunction with the compound of alkyl and the current potential lower than it, oxidized compound carries out and the used time, be preferably 0.5 quality % in conjunction with the content of the nonaqueous electrolytic solution of the compound of alkyl on aromatic rings more than, more preferably, more than 2 quality %, be preferably below 8 quality %, more preferably below 5 quality %.In addition, than on above-mentioned aromatic rings in conjunction with the compound of alkyl the content of the nonaqueous electrolytic solution of the oxidized compound of low current potential, more than being preferably 0.1 quality %, more preferably more than 0.2 quality %, be preferably below 1 quality %, more preferably below 0.5 quality %.

As the method that makes nonaqueous electrolytic solution contain these aromatic compounds, there is no particular restriction, and general is the method for nonaqueous electrolytic solution that makes an addition in advance before assembled battery.

In addition; by in nonaqueous electrolytic solution, add organic halogen series solvent such as Halogen carbonic ester, organosulfur compound, fluorine-containing organic lithium salt, phosphorous be organic solvent, siliceous be at least one compound of organic solvent, organic compounds containing nitrogen etc., can in the charging of the initial stage of battery, on the surface at positive active material, form surface protection film.Especially Organic fluoride series solvent, organic sulfur series solvent, the fluorine-containing organic lithium salt etc. such as preferred fluorine-containing carbonic ester, particularly, can enumerate F-DPC[C ₂f ₅cH ₂o (C=O) OCH ₂c ₂f ₅], F-DEC[CF ₃cH ₂o (C=O) OCH ₂cF ₃], HFE7100 (C ₄f ₉oCH ₃), sulfate pentahydrate (C ₄h ₉oSO ₂oC ₄h ₉), methyl ethidene sulfate [(OCH (CH ₃) CH ₂o-) SO ₂], fourth sulfone (C ₄h ₉sO ₂c ₄h ₉), polyimides salt [[N (Li) SO ₂oCH ₂(CF ₂) ₄cH ₂oSO ₂-] _n(wherein, the n in formula is 2～100)], (C ₂f ₅sO ₂) ₂nLi, [(CF ₃) ₂cHOSO ₂] ₂nLi etc.

Such additive, can distinguish separately and use, but particularly preferably by Organic fluoride series solvent and fluorine-containing organic lithium salt use.The intersection addition of its Organic fluoride series solvent and fluorine-containing organic lithium salt (also comprising independent situation), in the nonaqueous electrolytic solution total amount, more than being preferably 0.1 quality %, more preferably more than 2 quality %, more preferably more than 5 quality %, be preferably below 30 quality %, more preferably below 10 quality %.This is because if addition is too much, electrical characteristic may reduce, if very few, is difficult to form good tunicle.

The atomic ratio of the F of the above-mentioned surface protection film formed on the surface of positive active material, more than being preferably 15 atom %, more preferably more than 20 atom %, more preferably more than 25 atom %.But, if the atomic ratio of the F on the surface of positive active material is too much, the flash-over characteristic of battery has the tendency of reduction, so, its F atomic ratio is preferably below 50 atom %, more preferably below 40 atom %, more preferably below 30 atom %.Here; can not utilize the charging of battery as above to form the surface protection film of above-mentioned F of containing of positive active material or S, but adopt the positive active material (lithium-containing transition metal oxide particle) with described surface protection film to make positive pole (battery).

In addition, in order to improve the charge/discharge cycle characteristics of battery, in nonaqueous electrolytic solution, preferably add (OCH=CHO-) C=O, (OCH=C (CH ₃) O-) C=O, (OC (CH ₃)=C (CH ₃) O-) the vinylene carbonate or derivatives thereof such as C=O, vinylethylene carbonate (OCH ₂-CH (CH=CH ₂) O-) the such cyclic carbonate with vinyl of C=O, (OCH ₂-CHFO-) fluorine such as C=O, (OCHF-CHFO-) C=O replaces at least one in ethylene carbonate.As its addition, in the total amount of nonaqueous electrolytic solution, more than being preferably 0.1 quality, more preferably more than 0.5 quality, more than being particularly preferably 2 quality %.But if the content of additive is too much, the trend that has the part throttle characteristics of battery to reduce, so its content in the total amount of nonaqueous electrolytic solution is preferably below 10 quality %, more preferably below 5 quality %, particularly preferably below 3 quality %.

In the present invention, as nonaqueous electrolyte, except above-mentioned nonaqueous electrolytic solution, also can use the gelatinous polymer electrolyte.Such gelatinous polymer electrolyte, be equivalent to the electrolyte with the gelating agent gelation by above-mentioned nonaqueous electrolytic solution.When the nonaqueous electrolytic solution gelation, for example use Kynoar, polyethylene glycol oxide, straight chain polymer or their copolymers such as polyacrylonitrile, the polyfunctional monomer that utilizes the irradiation of ultraviolet ray or electron ray isoreactivity light to carry out the polymerization materialization (for example, tetramethylol methane tetraacrylate, two-trimethylolpropane tetra-acrylate, the ethoxylation tetramethylol methane tetraacrylate, dipentaerythritol hydroxyl five acrylate, the acrylate that four senses such as dipentaerythritol acrylate are above and with methacrylate more than four same senses of aforesaid propylene acid esters etc.) etc.But, in the situation of monomer, monomer self, not by the electrolyte gelation, plays a role the polymer of above-mentioned monomer polymerization materialization as gelating agent.

As mentioned above; while adopting polyfunctional monomer to make the nonaqueous electrolytic solution gelation; if necessary; as polymerization initiator; such as using benzoyl class, benzoin alkylether class, benzophenone, benzoylphenyl phosphinoxides, acetophenone class, thioxanthene ketone, Anthraquinones etc.; in addition, as the sensitive agent of polymerization initiator, also can use alkyl amine, amino ester etc.

In addition, in the present invention, as nonaqueous electrolyte, except above-mentioned nonaqueous electrolytic solution and gelatinous polymer electrolyte, also can use solid electrolyte.As its solid electrolyte, can use inorganic is any in solid electrolyte, organic system solid electrolyte.

As the positive pole the present invention relates to, can use the electrode that structure is following, that is, the anode mixture layer that will contain positive active material etc. is formed on the single or double of collector body for example.

The density of anode mixture layer of the present invention is 3.5g/cm ³above, be preferably 3.6g/cm ³above, 3.8g/cm more preferably ³above, battery of the present invention, make high density as above by anode mixture layer that will be relevant to positive pole, improves the loading of positive active material, realizes high capacity.But, if the density of anode mixture layer is too high, the wetability of nonaqueous electrolyte reduces, and therefore, for example is preferably 4.6g/cm ³below, 4.4g/cm more preferably ³below, 4.2g/cm more preferably ³below.

The density of said in this manual anode mixture layer is the value of utilizing following assay method to obtain.Cut positive pole with the area of regulation, adopt the electronic balance of minimum scale 1mg to measure its weight, the weight that deducts collector body from this weight is calculated the weight of anode mixture layer.In addition, measure the integral thickness of 10 place's positive poles with the micrometer of minimum scale 1 μ m, according to the mean value of the value of the thickness that deducts collector body from this thickness and the volume that area is calculated the anode mixture layer, divided by this volume, calculate the density of anode mixture layer by the weight with above-mentioned anode mixture layer.

In the positive active material of anode mixture layer, the lithium-containing transition metal oxide that its at least a portion contains the crystal structure with stratiform, this lithium-containing transition metal oxide contains at least one metallic element of selecting the group formed from Mg, Ti, Zr, Ge, Nb, Al and Sn.More particularly, form the metallic element of above-mentioned lithium-containing transition metal oxide, at least one element and the Li selected from the group of Co, Ni and Mn formation of take is main body, and, contain at least one element of selecting the group formed from Mg, Ti, Zr, Ge, Nb, Al and Sn.That is, form in the metallic element of above-mentioned metal oxide, as the element of main body, be Li with group from Co, Ni and Mn form 2～4 kinds of elements getting up of at least one element combinations of selecting.In metallic element, the ratio of these elements is preferably, and the ratio of Li is about 45～55 % by mole, and further, in the total amount of the metallic element beyond Li, it is about 80～99.99% that the ratio of Co, Ni and Mn adds up to.In addition, in the total amount of the metallic element beyond Li, the ratio of at least one metallic element of selecting the group formed from above-mentioned Mg, Ti, Zr, Ge, Nb, Al and Sn, preferably total is approximately 0.01～20 % by mole.The stability (the particularly stability of the charged state under high voltage) of lithium-containing transition metal oxide with above-mentioned such metallic element is good, therefore, can improve the reliabilities such as stability of battery.In addition, the stability with lithium-containing transition metal oxide of above-mentioned metallic element increases, so, also can suppress battery and repeatedly carry out the damage of charge and discharge cycles formula, therefore, by using described lithium-containing transition metal oxide, also can improve the charge/discharge cycle characteristics of battery.

In addition, positive active material, be the mixture of the lithium-containing transition metal oxide of more than two kinds that average grain diameter is different, in the size distribution curve obtained in the averaged particles determination method by following, preferably than d ₁₀and d ₉₀arithmetic average d _mthere is the size frequency peak on large particle diameter.By than d ₁₀and d ₉₀arithmetic average d _mthere is the size frequency peak on large particle diameter, the lithium-containing transition metal oxide that perhaps large lithium-containing transition metal oxide and average grain diameter are little by average grain diameter carries out and uses, make in the anode mixture layer, in gap at particle diameter between large lithium-containing transition metal oxide, fill the little lithium-containing transition metal oxide of particle diameter, therefore, can easily form as mentioned above highdensity anode mixture layer.More preferably use the lithium-containing transition metal oxide of more than two kinds that average grain diameter is different.The mixture of the lithium-containing transition metal oxide of more than two kinds that most preferably average grain diameter is different, and, in the size distribution curve obtained in the average grain diameter determination method by following, than d ₁₀and d ₉₀arithmetic average d _mthere is the size frequency peak on large particle diameter.Use the different lithium-containing transition metal oxide of more than two kinds of average grain diameter, can in the gap of large particle, mix the densification that little particle is realized electrode.In addition, than d ₁₀and d ₉₀arithmetic average d _mwhile thering is the size frequency peak on large particle diameter, because tailing off, little particle realizes that densification is preferred.Use lithium-containing transition metal oxide of more than two kinds that average grain diameter is different, than d ₁₀and d ₉₀arithmetic average d _mwhile having the size frequency peak on large particle diameter, because mix small-particle in the gap of large particle, and excessive small-particle tails off, and further realizes densification and preferably.

In this specification " average grain diameter " of said lithium-containing transition metal oxide, refer to adopt that Microtrac particle size distribution device " HRA9320 " that Nikkiso Company Limited manufactures is measured, by particle size distribution from small-particle, start to carry out the integration volume time the value (d of 50% diameter of integration rate of volume reference ₅₀) mid diameter.In addition, similarly, d ₁₀10% diameter, d ₉₀it is 90% diameter.Here, size distribution curve is that the frequency under each granularity is connected and makes with curve.

Above-mentioned " lithium-containing transition metal oxides of more than two kinds that average grain diameter is different ", as mentioned above, in the size distribution curve of these mixtures, preferably than d ₁₀and d ₉₀arithmetic average d _mon large particle diameter, have the size frequency peak (below, will exist the particle diameter at size frequency peak to be made as d _p).D _p/ d _mmore preferably more than 1.05, d _p/ d _mmore preferably more than 1.2, d _p/ d _mbe particularly preferably more than 1.3.In addition, d _p/ d _mmore preferably, below 1.6, more preferably, below 1.5, be particularly preferably below 1.45.In addition, more preferably, there is the situation at the peak more than 2 in this size distribution curve, for example, even be equally d _p/ d _m=1.3 situation, due to the peak had in size distribution curve more than 2, and make the density of anode mixture layer improve 0.1g/cm ³above.In the situation of such size distribution curve, adopt common peak separation method, be divided into the distribution of particles of large particle diameter and the distribution of particles of small particle diameter, from this particle diameter and integration volume, can obtain each average grain diameter (d of lithium-containing transition metal oxide ₅₀) and its blending ratio.

Above-mentioned " lithium-containing transition metal oxides of more than two kinds that average grain diameter is different " are carried out and the situation of use in, to have maximum average grain diameter material (below, be called " positive active material (A) ") average grain diameter be made as A, to have minimum average grain diameter material (below, be called " positive active material (B) ") average grain diameter while being made as B, B is preferably more than 0.15, below 0.6 with respect to ratio B/A of A.Average grain diameter with positive active material (A) of maximum average grain diameter, while being such value with the ratio of the average grain diameter of the positive active material with minimum average grain diameter (B), can more easily improve the density of anode mixture layer.

About positive active material (A), more than its average grain diameter for example is preferably 5 μ m, more preferably more than 8 μ m, more preferably more than 11 μ m.If the average grain diameter of positive active material (A) is excessive, there is the tendency that battery behavior reduces, so its average grain diameter for example is preferably below 25 μ m, more preferably below 20 μ m, more preferably below 18 μ m.

In addition, about positive active material (B), its average grain diameter for example is preferably below 10 μ m, more preferably below 7 μ m, more preferably below 5 μ m.If the average grain diameter of positive active material (B) is excessive, in the anode mixture layer, be difficult in the gap between the lithium-containing transition metal oxide particle large at particle diameter fill positive active material (B), so, often be difficult to improve the density of anode mixture layer.On the other hand, if the average grain diameter of positive active material (B) is too small, little interparticle voidage increases, therefore have and be difficult to put forward highdensity tendency, so, more than its average grain diameter for example is preferably 2 μ m, more preferably more than 3 μ m, more preferably more than 4 μ m.

In addition, positive active material, except the situation as only having above-mentioned positive active material (A) and above-mentioned positive active material (B), only use outside 2 kinds of lithium-containing transition metal oxides that average grain diameter is different, also can use the lithium-containing transition metal oxide of average grain diameter more than 3 kinds (for example, 3 kinds, 4 kinds, 5 kinds etc.).In the situation of the lithium-containing transition metal oxide that the average grain diameter of use more than 3 kinds is different, for example, preferably the lithium-containing transition metal oxide between the average grain diameter of the average grain diameter of positive active material (A) and positive active material (B) by average grain diameter, used with positive active material (A) with (B).

In the anodal lithium-containing transition metal oxide had, the content of the positive active material of average grain diameter minimum (B), for example, more than being preferably 5 quality %, more preferably more than 10 quality %, more preferably more than 20 quality %.While with above-mentioned amount, containing positive active material (B), the gap between the lithium-containing transition metal oxide particle that easily the landfill particle diameter is large, easily make the densification of anode mixture layer.On the other hand, when the content of the positive active material in the lithium-containing transition metal oxide that positive pole has (B) is too much, be difficult on the contrary improve the density of anode mixture layer, therefore, its content for example is preferably below 60 quality %, more preferably below 50 quality %, more preferably below 40 quality %.

Thereby, for example, when the anodal lithium-containing transition metal oxide had is above-mentioned positive active material (A) and positive active material (B), in whole lithium-containing transition metal oxides, the content of positive active material (A) is for example more than 40 quality %, more than being preferably 50 quality %, more preferably more than 60 quality %, be below 95 quality %, be preferably below 90 quality %, more preferably below 80 quality %.

In the anodal lithium-containing transition metal oxide had, positive active material (B) for example has above-mentioned average grain diameter, but, the little lithium-containing transition metal oxide of particle diameter like this, for example, in the charged state under high voltage, become the reason of the reliabilities such as fail safe of poor stability, infringement battery.

Therefore, in the situation of using the lithium-containing transition metal oxide of more than two kinds that average grain diameter is different, preferably the lithium-containing transition metal oxide in the average grain diameter minimum is in positive active material (B), at least contains at least one the metallic element M selected the group formed from Mg, Ti, Zr, Ge, Nb, Al and Sn ².Like this, can improve the stability of the positive active material that particle diameter is little (B), improve more reliably reliability and the charge/discharge cycle characteristics such as fail safe of battery.

In the situation of using the lithium-containing transition metal oxide of more than two kinds that average grain diameter is different, in these lithium-containing transition metal oxides, preferably the positive active material (B) of average grain diameter minimum contains above-mentioned metallic element M ²but, more preferably positive active material (B) lithium-containing transition metal oxide in addition, the lithium-containing transition metal oxide that for example has the positive active material (A) of maximum average grain diameter or have the average grain diameter different from positive active material (A) and positive active material (B), also contain above-mentioned metallic element M ².Positive active material (B) lithium-containing transition metal oxide in addition contains metallic element M ²the time, its stability (the particularly stability under the charged state under high voltage) improves, and therefore, can further improve reliabilities such as the charge/discharge cycle characteristics of battery and fail safe.

As positive active material (B), the lithium-containing transition metal oxide of preferably using following formula (1) to mean.

Li _xM ¹ _yM ² _zM ³ _vO ₂(1)

Here, in above-mentioned general formula (1), M ¹at least one transition metal among Co, Ni or Mn, M ²at least one metallic element of selecting the group formed from Mg, Ti, Zr, Ge, Nb, Al and Sn, M ³li, M ¹and M ²element in addition, 0.97<=x<1.02,0.8<=y<1.02,0.002<=z<=0.05,0<=v<=0.05.About z, more preferably, more than 0.004, more preferably, more than 0.006, in addition, more preferably be less than 0.02, more preferably be less than 0.01.This be because, if z is too small, the raising effect of the charge/discharge cycle characteristics of battery and fail safe is insufficient, if excessive, the electrical characteristic of battery starts to reduce.

In addition, as positive active material (B) lithium-containing transition metal oxide in addition, positive active material (A) for example, the lithium-containing transition metal oxide of preferably using following general formula (2) to mean.

Li _aM ¹ _bM ² _cM ³ _dO ₂(2)

Here, in above-mentioned general formula (2), M ¹, M ²and M ³select 0.97<=a<1.02,0.8<=b<1.02,0<=c<=0.02,0<=d<=0.02 from the element identical with above-mentioned general formula (1).Although M ¹, M ²and M ³from the element identical with above-mentioned general formula (1), select, but element kind and the component ratio selected, can be different because of the different active material of average grain diameter.Can be following combination, for example, in positive active material (B), M ²mg, Ti, Al, and in positive active material (A), M ²mg, Ti.Wherein, as shown in this example, preferred M ²in common element have at least a kind of, more preferably M ²in common element be two or more, more preferably more than three kinds.

In the situation of positive active material (A), c more preferably, more than 0.0002, more preferably, more than 0.001, more preferably is less than 0.005, and more preferably 0.0025.In addition, in the situation of positive active material (A), d more preferably, more than 0.0002, more preferably, more than 0.001, more preferably is less than 0.005, more preferably is less than 0.0025.This be because, because the particle diameter of positive active material (A) is large, even therefore M ²deng addition still less also can obtain effect, if but too much, the electrical characteristic of battery has the tendency of reduction.

The principal component that the preferred Co of lithium-containing transition metal oxide and/or Ni are transition metal, for example, the total amount of Co and Ni,, be preferably more than 50 % by mole in contained whole transition metals at lithium-containing transition metal oxide.

In addition, because the Co ratio of lithium-containing transition metal oxide is higher, more can improve the density of anode mixture layer, therefore preferably.For example, the transition metal M of above-mentioned general formula (1) and above-mentioned general formula (2) ¹in the Co ratio, be preferably more than 30 % by mole, more preferably more than 65 % by mole, more preferably more than 95 % by mole.

The a of the x of above-mentioned general formula (1) and above-mentioned general formula (2), because discharging and recharging of battery changes, when battery manufacture, be preferably more than 0.97, be less than 1.02.X and a are more preferably more than 0.98, more preferably more than 0.99, more preferably below 1.01, more preferably below 1.00.

The b of the y of above-mentioned general formula (1) and above-mentioned general formula (2), be preferably more than 0.8, more preferably, more than 0.98, more preferably, more than 0.99, is preferably and is less than 1.02, more preferably is less than 1.01, more preferably is less than 1.00.

The positive active material (B) meaned with above-mentioned general formula (1) and positive active material (B) lithium-containing transition metal oxide in addition meaned with above-mentioned general formula (2), the fail safe of battery improves more excellent effect, therefore, as M ²preferably contain Mg.And the positive active material (B) meaned with above-mentioned general formula (1) and positive active material (B) lithium-containing transition metal oxide in addition meaned with above-mentioned general formula (2), as M ², at least one metallic element that preferably contains Mg and select from the group of Ti, Zr, Ge, Nb, Al and Sn formation, now, improve stability under the charged state under high-tension electricity, these lithium-containing transition metal oxides more.

With regard to positive active material (B), from the angle that more effectively performance contains the effect that Mg produces, consider, its content for example, with respect to M ¹(for example, content Co), be preferably more than 0.1 % by mole, more preferably more than 0.15 % by mole, more preferably more than 0.2 % by mole.

In addition, when positive active material (B) contains Ti, Zr, Ge or Nb, from the angle that more effectively performance contains the above-mentioned effect that they produce, consider, its total amount is with respect to M ¹(for example, Co), be preferably more than 0.05 % by mole, more preferably more than 0.08 % by mole, more preferably more than 0.1 % by mole.In addition, when positive active material (B) contains Al or Sn, from the angle that more effectively performance contains the above-mentioned effect that they produce, consider, its total amount is with respect to M ¹(for example, Co), be preferably more than 0.1 % by mole, more preferably more than 0.15 % by mole, more preferably more than 0.2 % by mole.

But, with regard to positive active material (B), if the content of Mg is too much, there is the tendency of the part throttle characteristics reduction of battery, so its content is for example, with respect to M ¹(for example, content Co), be preferably and be less than 2 % by mole, more preferably is less than 1 % by mole, more preferably is less than 0.5 % by mole, is particularly preferably and is less than 0.3 % by mole.

In addition, with regard to positive active material (B), if the content of at least one metallic element of selecting the group formed from Ti, Zr, Ge, Nb, Al and Sn is too much, the raising effect of battery capacity often diminishes.Therefore, when positive active material (B) contains Ti, Zr, Ge or Nb, its total amount is with respect to M ¹(for example, Co), be preferably and be less than 0.5 % by mole, more preferably be less than 0.25 % by mole, more preferably be less than 0.15 % by mole.In addition, when positive active material (B) contains Al or Sn, its total amount is with respect to M ¹(for example, Co), be preferably and be less than 1 % by mole, more preferably be less than 0.5 % by mole, more preferably 0.3 % by mole.

In addition, with regard to positive active material (A), from the angle that more effectively performance contains the effect that Mg produces, consider, its content for example, with respect to M ¹(for example, content Co), be preferably more than 0.01 % by mole, more preferably more than 0.05 % by mole, more preferably more than 0.07 % by mole.

In addition, when positive active material (A) contains Ti, Zr, Ge or Nb, from the angle that more effectively performance contains the above-mentioned effect that they produce, consider, its total amount is with respect to M ¹(for example, Co), be preferably more than 0.005 % by mole, more preferably more than 0.008 % by mole, more preferably more than 0.01 % by mole.In addition, when positive active material (A) contains Al or Sn, from the angle that more effectively performance contains the above-mentioned effect that they produce, consider, its total amount is with respect to M ¹(for example, Co), be preferably more than 0.01 % by mole, more preferably more than 0.05 % by mole, more preferably more than 0.07 % by mole.

But, with regard to positive active material (A), if the content of Mg is too much, there is the tendency of the part throttle characteristics reduction of battery, therefore, its content is for example with respect to M ¹(for example, content Co), be preferably and be less than 0.5 % by mole, more preferably is less than 0.2 % by mole, more preferably is less than 0.1 % by mole.

In addition, with regard to positive active material (A), if the content of at least one metallic element of selecting the group formed from Ti, Zr, Ge, Nb, Al and Sn is too much, the raising effect of battery capacity often diminishes.Therefore, when positive active material (A) contains Ti, Zr, Ge or Nb, its total amount is with respect to M ¹(for example, Co) be preferably and be less than 0.3 % by mole, more preferably be less than 0.1 % by mole, more preferably be less than 0.05 % by mole.In addition, when positive active material (A) contains Al or Sn, its total amount is with respect to M ¹(for example, Co), be preferably and be less than 0.5 % by mole, more preferably be less than 0.2 % by mole, more preferably be less than 0.1 % by mole.

In addition, use in the situation of positive active material (A) and positive active material (B) lithium-containing transition metal oxide in addition, with regard to the lithium-containing transition metal oxide related to, from the angle of the effect that more effectively performance produces containing Mg, to consider, its content is for example with respect to M ¹(for example, Co), be preferably more than 0.01 % by mole, more preferably more than 0.05 % by mole, more preferably more than 0.07 % by mole.

In addition, in the situation that positive active material (A) and positive active material (B) lithium-containing transition metal oxide in addition contain Ti, Zr, Ge or Nb, from the angle that more effectively performance contains the effect that they produce, consider, its total amount is with respect to M ¹(for example, Co), be preferably more than 0.005 % by mole, more preferably more than 0.008 % by mole, more preferably more than 0.01 % by mole.In addition, in the situation that utmost point active material (A) and positive active material (B) lithium-containing transition metal oxide in addition contain Al or Sn, from the angle that more effectively performance contains the effect that they produce, consider, its total amount is with respect to M ¹(for example, Co), be preferably more than 0.01 % by mole, more preferably more than 0.05 % by mole, more preferably more than 0.07 % by mole.

But, with regard to positive active material (A) and positive active material (B) lithium-containing transition metal oxide in addition, if the content of Mg is too much, there is the tendency of the part throttle characteristics reduction of battery, therefore, its content is for example with respect to M ¹(for example, Co), be preferably and be less than 2 % by mole, more preferably be less than 1 % by mole, more preferably be less than 0.5 % by mole, be particularly preferably and be less than 0.3 % by mole.

In addition, with regard to positive active material (A) and positive active material (B) lithium-containing transition metal oxide in addition, if the content of at least one metallic element of selecting the group formed from Ti, Zr, Ge, Nb, Al and Sn is too much, the raising effect of battery capacity often diminishes.Therefore, in the situation that positive active material (A) and positive active material (B) lithium-containing transition metal oxide in addition contain Ti, Zr, Ge or Nb, its total amount is with respect to M ¹(for example, Co), be preferably and be less than 0.5 % by mole, more preferably be less than 0.25 % by mole, more preferably 0.15 % by mole.In addition, in the situation that positive active material (A) and positive active material (B) lithium-containing transition metal oxide in addition contain Al or Sn, its total amount is with respect to M ¹(for example, Co), be preferably and be less than 1 % by mole, more preferably be less than 0.5 % by mole, more preferably be less than 0.3 % by mole.

With regard to positive active material (B) and other lithium-containing transition metal oxide, metallic element M ²the mode that contains there is no particular restriction, for example, may reside on its particle, also can be in active material equably solid solution exist, the form that also can have CONCENTRATION DISTRIBUTION distributes unevenly in active material inside, also can be used as compound and form from the teeth outwards layer, but preferably solid solution equably.

The above-mentioned general formula (1) and the related element M of above-mentioned general formula (2) that mean positive active material (B) and other lithium-containing transition metal oxide ³, be Li, M ¹and M ²element in addition.Positive active material (B) and other lithium-containing transition metal oxide, in the scope of not damaging effect of the present invention, can contain M ³, also can not contain M ³.

As element M ³, for example, can enumerate Li alkali metal (Na in addition, K, Rb etc.), alkaline-earth metal (Be beyond Mg, Ca, Sr, Ba etc.), metal (the Sc of IIIa family, Y, La etc.), Ti, IVa family metal (Hf etc.) beyond Zr, metal (the V of Va family beyond Nb, Ta etc.), metal (the Cr of VIa family, Mo, W etc.), metal (the Tc of VIIb family beyond Mn, Re etc.), except Co, metal (the Fe of VIII family of Ni, Ru, Rh etc.), metal (the Cu of Ib family, Ag, Au etc.), Zn, metal (the B of IIIb family beyond Al, Ca, In etc.), Sn, IVb family metal (Si etc.) beyond Pb, P, Bi etc.

Metallic element M ²stability raising to lithium-containing transition metal oxide has contribution, still, if its content is too much, can damage the effect of emitting the Li ion of receiving, and therefore often reduces battery behavior.The particle diameter of positive active material (B) with minimum average grain diameter is little, and stability is lower, so preferably as the M of stabilizing element ²content high to certain degree, in addition, the particle diameter of positive active material (B) is little, surface area is large, so active high, even contain M ², also little on the impact of receiving the effect of emitting of Li ion.

On the other hand, the lithium-containing transition metal oxide that size ratio is larger [positive active material (B) lithium-containing transition metal oxide in addition], compare with positive active material (B), and surface area is little, active low, therefore, contains M ²and easily damage the effect of emitting of receiving of Li ion.

Therefore, the metallic element M that there is the positive active material (B) of minimum average grain diameter ²content, preferably than the M of positive active material (B) lithium-containing transition metal oxide in addition ²content many.

That is, the c of the z of above-mentioned general formula (1) and above-mentioned general formula (2), preferably meet z > relation of c.Z is more than 1.5 times of c more preferably, more preferably, more than 2 times, are particularly preferably more than 3 times.On the other hand, if z is excessive with respect to c, have the tendency of the part throttle characteristics reduction of battery, therefore, z more preferably is less than 5 times of c, more preferably is less than 4 times, is particularly preferably and is less than 3.5 times.

The lithium-containing transition metal oxide related to as positive pole, use has in the situation of material of the average grain diameter more than 3 kinds, about positive active material (B) lithium-containing transition metal oxide in addition with minimum average grain diameter, at the positive active material with maximum average grain diameter (A), and between lithium-containing transition metal oxide in addition, M ²relation with contents there is no particular restriction, can the former containing M ²some more, also can the latter contain M ²some more, but also both M ²content identical.Preferred form is, the little lithium-containing transition metal oxide of average grain diameter, M ²content more.That is, for example, use in the situation of the lithium-containing transition metal oxide with 3 kinds of average grain diameters, preferred mode is to have the M of the positive active material (B) of minimum average particle diameters ²content is maximum, secondly, has the M containing lithium metal oxide of the average grain diameter between positive active material (A) and positive active material (B) ²content is many, has the M of the positive active material (A) of maximum average grain diameter ²content is minimum.

In addition, use in the situation of the lithium-containing transition metal oxide of more than two kinds that average grain diameter is different, between the different material of average grain diameter, can there is identical composition, also can there is different compositions by the different material of each average grain diameter.For example, lithium-containing transition metal oxide is in the situation of the positive active material (B) with minimum average grain diameter and the positive active material (A) with maximum average grain diameter, can be such combination, that is, positive active material (A) be LiCo _0.998mg _0.0008ti _0.0004al _0.0008o ₂, positive active material (B) is LiCo _0.334ni _0.33mn _0.33mg _0.0024ti _0.0012al _0.0024o ₂.

Above-mentioned positive active material (lithium-containing transition metal oxide), form with the manufacturing process of specific battery through specific synthesis procedure.For example,, in order to obtain by containing Co as transition metal M ¹the different material of particle diameter that forms of lithium-containing transition metal oxide, usually, to dripping the alkali such as NaOH in the acidic aqueous solution of Co, make it as Co (OH) ₂precipitate.Made the coprecipitation compounds with the xenogenesis element in order to precipitate uniformly after, also can burn till from making Co ₃o ₄.Make the time of precipitation by control, and can control the particle diameter of precipitation, sedimentary particle diameter now is also the Co after burning till ₃o ₄the important adjusting factor of particle diameter.

When synthetic positive active material, need to select specific mixing condition, firing temperature, burn till atmosphere, firing time, initiation material and specific battery manufacture condition.The synthetic mixing condition of positive active material for example, preferably adds ethanol or water in material powder, with planetary ball mill, mixes more than 0.5 hour, and more preferably the volumetric ratio of second alcohol and water is 50:50, with planetary ball mill, mixes more than 20 hours.By this mixed processes, material powder can fully be pulverized, be mixed, and prepares uniform dispersion liquid.Utilize spray dryer etc. to be dried with the state that keeps homogeneity.Preferred firing temperature is 750～1050 ℃, and preferred firing temperature is 950～1030 ℃.In addition, preferably burning till atmosphere is in air.Preferred firing time is 10～60 hours, and preferred firing time is 20～40 hours.

About above-mentioned positive active material, as the preferred Li in Li source ₂cO ₃as dissimilar metal sources such as Mg, Ti, Ge, Zr, Nb, Al, Sn, the preferred oxide of the following particle diameter of their metal nitrate, hydroxide or 1 μ m, when being used the coprecipitate of hydroxide, the xenogenesis element easily is distributed in active material equably, therefore more preferably.

Metallic element amount in the positive active material of anode mixture layer, analyze by inductively coupled plasma (ICP), measures each amount of element and try to achieve.In addition, about Li amount, can adopt the atom extinction etc. of method for distinguishing to measure.Usually, in the state of electrode (positive pole), the different positive active material to particle diameter, it is difficult that the active material particle that separates respectively the active material particle of large particle diameter and small particle diameter is measured amount of element.Therefore, the active material admixture that combined amount is known, as standard, can be used EPMA (electron ray probe unit) etc., and content and the content ratio of the element in the particle of the particle of small particle diameter and large particle diameter compared.In addition, with processing electrodes (positive pole) such as METHYLPYRROLIDONEs (NMP), by active material particle after electrode peels off precipitation particles, after washing, drying, the particle size distribution of the particle that mensuration obtains, the peak that carries out particle size distribution separates, and judges in the situation with granularity of more than two kinds, be classified into large particle and small particle diameter particle, can measure with ICP the amount of element of the point of population separately.

In the icp analysis of the metallic element amount of the positive active material for measuring this specification, the method adopted is: the active material of the about 5g of accurate weighing, put into the beaker of 200ml, the chloroazotic acid that adds 100ml, heating is concentrated until liquid measure is approximately 20～25ml, after cooling, the quantitative filter paper " No.5B " of manufacturing with Advantech Co., Ltd. carrys out the separating solids material, after filtrate and washing lotion being put into to the volumetric flask constant volume dilution of 100ml, the sequential type icp analysis device " IPIS1000 " that adopts Japanese Jarrell-Ash company to manufacture is measured.

Among the different lithium-containing transition metal oxide of more than two kinds of the above-mentioned average grain diameter that anode mixture has, about thering is the lithium-containing transition metal oxide of minimum average grain diameter, utilize above-mentioned icp analysis to obtain by Mg, Ti, Zr, Ge, Nb, the containing ratio (I) of at least one metallic element of selecting in the group that Al and Sn form, about the lithium-containing transition metal oxide beyond the lithium-containing transition metal oxide with minimum average grain diameter, utilize above-mentioned icp analysis to obtain by Mg, Ti, Zr, Ge, Nb, the containing ratio of at least one metallic element of selecting in the group that Al and Sn form, this is the containing ratio (II) of the metallic element that the metallic element that relates to above-mentioned containing ratio (I) is identical, the ratio (I)/(II) of containing ratio (I) and containing ratio (II) is equivalent to z in above-mentioned general formula (1) and the relation of the c in above-mentioned general formula (2), (I) value/(II) is more preferably more than 1.5, more preferably more than 2, be particularly preferably more than 3.In addition, when z is excessive with respect to c, have the tendency of the part throttle characteristics reduction of battery, therefore, value (I)/(II) more preferably is less than 5, more preferably is less than 4, is particularly preferably and is less than 3.5.

For example by following method, make anodal.At first, as required, add conductive auxiliary agent (for example, graphite, carbon black, acetylene black etc.) in the lithium-containing transition metal oxide as positive active material, further add adhesive (for example, Kynoar, polytetrafluoroethylene etc.) and prepare anode mixture.Adopt solvent by this anode mixture make pasty state (can adhesive in advance solvent in solvent after, with positive active material etc., mix), prepare the paste containing anodal utmost point mixture.Coat containing the paste of anode mixture the positive electrode collector consisted of aluminium foil etc. by what obtain, drying forms the anode mixture layer, makes positive pole through the operation of calendering as required.By average grain diameter, different lithium-containing transition metal oxide of more than two kinds [for example, positive active material (A) and positive active material (B) are for the situation of positive active material, recently mix these lithium-containing transition metal oxides by the quality of regulation, to adding above-mentioned conductive auxiliary agent in this mixture, adhesive is made anode mixture, by the anode mixture that obtains in after operation.But, anodal manufacture method is not limited to above-mentioned illustrative method, also can use other method.

The thickness of anode mixture layer for example, is preferably 30～200 μ m.In addition, for the thickness of anodal collector body, for example be preferably 8～20 μ m.

And, in the anode mixture layer, more than being preferably 96 quality % as the content of the lithium-containing transition metal oxide of active material, more preferably more than 97 quality %, more preferably, more than 97.5 quality %, be preferably below 99 quality %, more preferably below 98 quality %.In addition, the content of the adhesive in the anode mixture layer for example, more than being preferably 1 quality %, more preferably, more than 1.3 quality %, more preferably, more than 1.5 quality %, be preferably below 4 quality %, more preferably below 3 quality %, more preferably below 2 quality %.And, the content of the conductive auxiliary agent of anode mixture layer, for example, more than being preferably 1 quality %, more preferably more than 1.1 quality %, more preferably more than 1.2 quality %, be preferably below 3 quality %, more preferably below 2 quality %, more preferably below 1.5 quality %.

This be because, if the ratio of the active material in the anode mixture layer is very few, be difficult to realize high capacity, the density of anode mixture layer also is difficult to increase, on the other hand, if too much, resistance increases, or damages anodal formative.In addition, if the content of the adhesive in the anode mixture layer is too much, the high capacity difficulty, if very few, reduce with the adaptation of collector body, exists and produce electrode scum silica frost equally likely possibility, therefore preferred above-mentioned suitable composition.In addition, the content of the conductive auxiliary agent in the anode mixture layer, if too much, increase the density that is difficult to fully improve the anode mixture layer, and the high capacity difficulty, if very few, can not conduct electricity preferably, relevant to the reduction of the charge/discharge cycle characteristics of battery and part throttle characteristics.

Non-aqueous secondary batteries of the present invention, as long as have above-mentioned nonaqueous electrolyte and above-mentioned positive pole, be not particularly limited for other inscape and structure, can be applied in the various inscapes or the structure that adopt in known non-aqueous secondary batteries in the past.

The negative electrode active material related to as negative pole, so long as the material of Li ion doping dedoping can be got final product, for example, can enumerate the material with carbon element such as sintered body, carbonaceous mesophase spherules, carbon fiber, activated carbon of graphite, thermally decomposed carbon class, coke class, vitreous carbon class, organic high molecular compound.In addition, oxide, the Li of the alloy such as Si, Sn, In or Si, the Sn etc. that at the electronegative potential close with Li, can discharge and recharge _2.6co _0.4the compounds such as nitride of the Li such as N and Co also can be used as negative electrode active material.In addition, also can be by the part of graphite, with can with the displacements such as Li alloyed metal (AM) or oxide.By graphite, when the negative electrode active material, the voltage of Li when benchmark will completely charge of take is regarded 0.1V as, therefore, can calculate easily positive electrode potential with the voltage that adds 0.1V to cell voltage, so can easily control anodal charging potential preferably.

As the form of graphite, for example, the preferred face interval (d of 002 ₀₀₂) be below 0.338nm.This be because, more high negative pole (anode mixture layer described later) densification that more easily makes of crystallographic.But, if d ₀₀₂excessive, the flash-over characteristic of highdensity negative pole or part throttle characteristics are low, so, d ₀₀₂more than being preferably 0.335nm, more preferably more than 0.3355nm.

In addition, about the crystallite size (Lc) of the c-axis direction of graphite, more than being preferably 70nm, more preferably more than 80nm, more preferably more than 90nm.This be because, the anodal current potential of smooth, the easy control of the charging curve that Lc is large, and can capacity increasing.On the other hand, if Lc is excessive, highdensity negative pole has the tendency that battery capacity is low, and Lc is preferably and is less than 200nm.

In addition, the specific area of graphite is preferably 0.5m ²more than/g, 1m more preferably ²more than/g, 2m more preferably ²more than/g, in addition, be preferably 6m ²below/g, 5m more preferably ²below/g.There is to a certain degree the tendency that characteristic reduces if the specific area of graphite is little, on the other hand, if excessive, easy would reacting of impact and nonaqueous electrolyte.

Preferably take native graphite as raw material for the graphite of negative pole, consider from the angle of high capacity, more preferably mixed the graphite of the different graphite of more than two kinds of surface crystal.Cheap and the high power capacity of native graphite, therefore, can make the negative pole that cost performance is high like this.Common native graphite, because the densification of negative pole easily reduces battery capacity, still, carrys out the low graphite of crystallographic of blending surface by surface treatment, can reduce the reduction of battery capacity.

The crystallographic on the surface of graphite can judge by Raman spectrum analysis.R value [the R=I of the raman laser while with the argon laser of wavelength 514.5nm, exciting graphite ₁₃₅₀/ I ₁₅₈₀(1350cm ^-1neighbouring raman scattering intensity and 1580cm ^-1near the ratio of raman scattering intensity)] be more than 0.01, surperficial crystallographic reduces a bit than native graphite.For example, thereby, as the graphite that utilizes surface treatment that surperficial crystallographic is reduced,, the R value of the graphite preferably used, be more than 0.01,, more than 0.1, is more preferably below 0.5, more preferably below 0.3, more preferably below 0.15.Containing of the graphite that the crystallographic on above-mentioned surface is low is proportional, is preferably 100 quality % for the densification of graphite, still, in order to prevent the low of battery capacity, more than being preferably 50 quality % in whole graphite, more preferably more than 70 quality %, more than being particularly preferably 85 quality %.

In addition, if the average grain diameter of graphite is too small, irreversible capacity increases, more than therefore being preferably 5 μ m, more preferably more than 12 μ m, more preferably more than 18 μ m.In addition, from the angle of the densification of negative pole, consider, the average grain diameter of graphite is preferably below 30 μ m, more preferably below 25 μ m, more preferably below 20 μ m.

For example can make negative pole in order to the below legal system.Add adhesive etc. as required in above-mentioned negative electrode active material, mix and be prepared into cathode agent, it is scattered in solvent and makes paste.Here, preferred adhesive in advance solvent after solvent, with negative electrode active material etc., mix again.The above-mentioned muddle containing cathode agent is distributed in to the negative electrode collector consisted of Copper Foil etc., drying forms anode mixture layer, can obtain negative pole through the pressurized treatments operation.The manufacture method of negative pole is not limited to said method, also can adopt additive method.

The density of anode mixture layer (density after the pressurized treatments operation) is preferably 1.70g/cm ³above, 1.75g/cm more preferably ³above.According to the solid density of graphite, the upper limit of the density of anode mixture layer is 2.1～2.2g/cm ³, but from the compatibility with nonaqueous electrolyte, to consider, the density of anode mixture layer is preferably 2.0g/cm ³below, more preferably 1.9g/cm ³below.In above-mentioned pressurized treatments operation, can pressurize more uniformly by anticathode, so, compared with pressurized treatments once, preferably implement pressurized treatments repeatedly.

Adhesive for negative pole is not particularly limited, consider from the angle that improves active material ratio, capacity increasing, preferably reduce use amount, due to such reason as far as possible, therefore, it is exactly suitable having the aqueous resin of the character of dissolving or disperseing and the mixture of rubber resin in water.This is because, even aqueous resin on a small quantity, also can participate in the dispersion of graphite, the caused anode mixture layer of dilation of the electrode when rubber series resin can prevent due to the charge and discharge cycles of battery is peeled off from collector body.

As aqueous resin, can enumerate the celluosic resins such as carboxymethyl cellulose, hydroxypropyl cellulose, the polyethers such as polyvinylpyrrolidone, Hydrin, polyvinyl pyridine, polyvinyl alcohol, poly(ethylene oxide), polyethylene glycol are resin etc.As the rubber series resin, can enumerate latex, butyl rubber, fluorubber, butadiene-styrene rubber, acrylonitrile-butadiene copolymer rubber, ethylene-propylene-diene copolymer, polybutadiene, ethylene-propylene-diene copolymer (EPDM) etc.For example, from the dispersion of above-mentioned graphite with prevent that the angle of peeling off from considering, more preferably the butadiene copolymer system rubber such as the cellulose ether compound such as carboxymethyl cellulose and butadiene-styrene rubber are carried out and use.Particularly preferably the butadiene copolymer system rubber such as carboxymethyl cellulose and butadiene-styrene rubber, acrylonitrile-butadiene copolymer rubber are carried out and use.This is because the cellulose ether compounds such as carboxymethyl cellulose, mainly bring into play viscosifying action to the paste that contains cathode agent, the rubber series adhesives such as butadiene-styrene rubber, anticathode mixture performance adhesive effect.Like this, the rubber series adhesives such as the cellulose ether compound such as carboxymethyl cellulose and butadiene-styrene rubber are carried out and the used time, as both ratios, with mass ratio, be preferably 1:1～1:15.

The thickness of anode mixture layer, for example, be preferably 40～200 μ m.In addition, the thickness for the collector body of negative pole, for example, be preferably 5～30 μ m.

And, with regard to anode mixture layer, the content of adhesive is (and with in multiple situation, its total amount) more than being preferably 1.5 quality %, more preferably, more than 1.8 quality %, more preferably, more than 2.0 quality %, be preferably and be less than 5 quality %, more preferably be less than 3 quality %, more preferably be less than 2.5 quality %.If the amount of binder in anode mixture layer is too much, discharge capacity reduces, if very few, the bonding force between particle reduces.The content of the negative electrode active material of anode mixture layer, for example, be preferably and surpass 95 quality %, below 98.5 quality %.

The barrier film the present invention relates to, there is directivity on hot strength, and, keep good insulating properties, in addition, from the angle that reduces thermal contraction, consider, more than its thickness is preferably 5 μ m, more preferably more than 10 μ m, more preferably more than 12 μ m, be preferably and be less than 25 μ m, more preferably be less than 20 μ m, more preferably be less than 18 μ m.In addition, the air permeability of barrier film for example, is preferably 500 seconds/below 100ml, 300 seconds/below 100ml more preferably, more preferably 120 seconds/below 100ml.The air permeability of barrier film is less, and part throttle characteristics is higher, and still, owing to easily producing internal short-circuit, therefore, its air permeability is preferably 50 seconds/more than 100ml.The percent thermal shrinkage of the TD direction of barrier film is less, when temperature rises, more is difficult to occur internal short-circuit, therefore, preferably uses the percent thermal shrinkage little barrier film of trying one's best, for example, and the more preferably barrier film of percent thermal shrinkage below 10%, the more preferably barrier film below 5%.In addition, in order to suppress thermal contraction, preferably use real-time heat treated barrier film at the temperature of 100～125 ℃ of left and right in advance.The barrier film of such percent thermal shrinkage and the positive electrode the present invention relates to are combined, form battery, thereby make the working stability under higher temperature, thus recommended.

The percent thermal shrinkage of the TD direction of barrier film refers to, by 30mm square barrier film under 105 ℃ standing 8 hours the time, on the TD direction shrinkage of the part of maximum collapse.

In addition, the intensity of barrier film, as the hot strength on the MD direction, for example, be preferably 6.8 * 10 ⁷n/m ²above, more preferably 9.8 * 10 ⁷n/m ²above.In addition, preferably the hot strength of TD direction is less than MD direction, for example, the hot strength of TD direction is with respect to the ratio (hot strength on the hot strength of TD direction/MD direction) of the hot strength on the MD direction more preferably below 0.95, more preferably below 0.9, in addition, more preferably more than 0.1.Said TD direction, refer to the film resin of barrier film manufacture pull the perpendicular direction of direction (MD direction).

In addition, more than the puncture intensity of barrier film is preferably 2.0N, more preferably more than 2.5N.This value is higher, the more difficult short circuit of battery.But, its higher limit is that the constituent material by barrier film decides usually substantially, and for example, in the situation of the barrier film of polyethylene system, the 10N left and right is higher limit.

In non-aqueous secondary batteries in the past, when positive electrode potential with the Li benchmark with the high voltage more than 4.35V charged, while stopping being discharged with the voltage higher than 3.2V, the crystal structure of positive active material damages, easily cause volume lowering, perhaps thermal stability reduces and the obstacles such as generation battery-heating, lacks practicality.For example, even use the positive active material that has added the xenogenesis elements such as Mg, Ti, also can reduce the volume lowering produced along with fail safe, charge and discharge cycles, but and insufficient.In addition, the expansion of the anodal insufficient easy generation battery of fillibility.

On the other hand, the present invention is by adopting above-mentioned formation to improve the non-aqueous secondary batteries of each effect of high capacity characteristics, charge/discharge cycle characteristics, fail safe and repression of swelling, even common voltage (cell voltage 4.2V) also can obtain effect, in addition, even take Li as benchmark by positive pole charge to 4.35V (cell voltage 4.25V) high voltage, finish electric discharge with the high voltage more than cell voltage 3.2V, the crystal structure of positive active material is also more stable, can suppress volume lowering and thermal stability and reduce.

In addition, the positive electrode active material that non-aqueous secondary batteries in the past is related, average electrical is forced down, therefore, when the end of charge voltage at monocell be with the condition more than the 4.35V of Li benchmark under repeated charge-discharge cycles when test, positive pole has a large amount of Li ions to come in and go out.This is with by battery, to carry out charge and discharge cycles test identical overcharging under condition.Thereby, under harsh like this condition, if use positive active material in the past can not maintain crystal structure, produce thermal stability and reduce, or the unfavorable condition such as charge and discharge circulation life is short.On the other hand, if use the related positive active material of battery of the present invention, can eliminate above unfavorable condition, therefore, a kind of like this non-aqueous secondary batteries can be provided, even the positive electrode potential when it completely charges is more than the 4.35V with the Li reference potential, further wishes it is under the such high potential of 4.5V～4.6V, also can reversibly discharge and recharge.

Said above-mentioned " full charging " refers to, with the 0.2C current value, carries out constant current charge, until the voltage of regulation then, carries out constant-voltage charge under the voltage of regulation, take the charging of total ascent time under the condition of 8 hours of this constant current charge and this constant-voltage charge.In addition, for example, non-aqueous secondary batteries of the present invention, in the situation of the graphite cathode (containing the negative pole of graphite as negative electrode active material) that the Li reference potential while having full charging is 0.1V, cell voltage, to be charged more than 4.45V, is counted as to positive electrode potential and is essentially the above charging of 4.35V.

Non-aqueous secondary batteries of the present invention, can bring into play above-mentioned high voltage, high power capacity and safe characteristics, can for example, as the power supply of various device, notebook computer, the defeated formula computer of pen, pocket computer, notebook type Word message processor, pocket Word message processor, TV book player, mobile phone, the radio telephone extension set, the automated page ink recorder, hand held controller, portable copier, electronic memo, electronic calculator, LCD TV, electric razor, electric tool, electronic translator, automobile telephone, transceiver, audio input device, storage card, stand-by power supply, recorder, broadcast receiver, stereophone, portable printer, portable cleaner, portable CD, pantoscope, the power supply that the mini-plants such as navigation positioning system are used, or refrigerator, air-conditioning, TV, sound equipment, water heater, microwave oven, dishwasher, washing machine, drying machine, game machine, lighting apparatus, toy, sensing equipment, load governor, Medical Devices, automobile, electric motor car, golf cart, electrically driven truck, safety system, the power supply of the large-scale medium size installations such as electric power storage system or accessory power supply, stand-by power supply.In addition, except civilian, also can be used for the universe purposes.Wherein, small portable apparatus especially, the effect of high capacity is high, with being selected to the following portable set of weight 3kg, more preferably for the portable set below 1kg.In addition, the lower limit of the weight of portable set is not particularly limited, but for effect to a certain degree, preferably with the same degree of the weight of battery, be for example more than 10g.More than the charging voltage per unit battery of the battery of equipment is preferably to 4.35V with the lithium benchmark, with the lithium benchmark more preferably more than 4.5V.This be because, but the service time of extension device, and the present invention can suppress the deteriorated harmful effect that circulates effectively.

Embodiment

Below, based on embodiment, the present invention is described in detail.But, following embodiment is not limited to the present invention, before not breaking away from. and change enforcement in the scope of rear purport, also all be contained in technical scope of the present invention.

Embodiment 1

Anodal making

To mix LiCo with mass ratio 65:35 _0.998mg _0.0008ti _0.0004al _0.0008o ₂[average grain diameter 12 μ m, positive active material (A)] and LiCo _0.994mg _0.0024ti _0.0012al _0.0024o ₂[average grain diameter 5 μ m, positive active material (B)] material 97.3 mass parts and as material with carbon element 1.5 mass parts of conductive auxiliary agent, in the constant feeder of input as the pulvis feedway, in addition, regulate the input amount of nmp solution of the Kynoar (PVDF) of 10 quality % concentration, make solid component concentration when mixing be adjusted to 94 constant quality %, this material is controlled and made time per unit that fixing input amount be arranged, and, mixing by carrying out in its input double screw extruder, prepare the paste containing anode mixture.

In addition, use additive method, above-mentioned positive active material (A) and positive active material (B) are dissolved in respectively in chloroazotic acid, confirm the ratio of the element that contains with icp analysis and atomic absorption analysis, also can confirm the above-mentioned composition formula of respectively doing for oneself.

Then, the paste containing anode mixture obtained is put in planetary-type mixer, added nmp solution and the NMP of the PVDF of 10 quality % concentration to be diluted, be adjusted to the viscosity that can be coated with.By after this dilution containing the paste of anode mixture by 70 purpose nets, remove large contain thing after, coating equably thickness is the two sides of the positive electrode collector consisted of aluminium foil of 15 μ m, drying forms membranaceous anode mixture layer.The solid constituent ratio of dried anode mixture layer, positive active material: conductive auxiliary agent: PVDF is 97.3:1.5:1.2 by quality ratio.Then, pressurized treatments, after cutting into the size of regulation, weld the lead-in wire body of aluminum, makes the positive pole of sheet.The density of the anode mixture layer after pressurized treatments (anodal density) is 3.86g/cm ³, the thickness of anode mixture layer (thickness on two sides, that is, anodal gross thickness deducts the thickness of thickness of the aluminium foil of positive electrode collector, below identical) be 135 μ m.

The Microtrac particle size distribution device " HRA9320 " that adopts Nikkiso Company Limited to manufacture, the particle size distribution of mensuration positive active material (A) and mixture (B).Size frequency peak d _pbe present in 12 μ m and 5 μ m, on the other hand, d ₁₀for 4.3m, d ₉₀be 13.8 μ m, d _mvalue is 9 μ m.D _p/ d _mbe 1.3.

Here, positive active material (A), with respect to Co, Mg is 0.08 % by mole, and Ti is 0.04 % by mole, and Al is 0.08 % by mole.In addition, small the resolver of electron ray " EPMA1600 " that adopts Shimadzu Corporation to manufacture, the metallic element M in the cross section of mensuration particle ²concentration, result, at surface element and central part, all do not observe Mg, Ti, Al has concentration difference.

In addition, positive active material (B), with respect to Co, Mg is 0.24 % by mole, and Ti is 0.12 % by mole, and Al is 0.24 % by mole, with positive active material (A), similarly measures the metallic element M in the cross section of particle ², at surface element and central part, all do not observe Mg, Ti, Al has concentration difference.In addition, about metallic element M ²content, positive active material (B), with respect to positive active material (A), take mole is benchmark, Mg is 3 times, Ti is 3 times, Al is 3 times.

The making of negative pole

To be that [purity is more than 99.9%, average grain diameter 18 μ m, the interplanar distance (d of 002 for material with carbon element (A) as the graphite of negative electrode active material ₀₀₂)=0.3356nm, the size of the crystallite of c-axis direction (Lc)=100nm, the R value (1350cm of the Raman spectrum while exciting with the argon laser of wavelength 514.5nm ^-1neighbouring peak intensity and 1580cm ^-1near the ratio [R=I1350/I1580] of peak intensity)=0.18] 70 mass parts, with graphite be that [purity is more than 99.9%, average grain diameter 21 μ m, d for material with carbon element (B) ₀₀₂=0.3363nm, Lc=60nm, R value=0.11] 30 mass parts are mixed, and by these mixture 98 mass parts, carboxymethyl cellulose: 1 mass parts, butadiene-styrene rubber 1 mass parts are mixed under water exists, and prepare the paste containing cathode agent of pulpous state.The muddle containing cathode agent obtained is distributed in to the two sides of the negative electrode collector consisted of Copper Foil that thickness is 10 μ m, drying forms cathode agent, with roller, carries out pressurized treatments, until the density of anode mixture layer is 1.75g/cm ³, after cutting into the size of regulation, weld the lead-in wire body of nickel system, make the negative pole of sheet.

The preparation of nonaqueous electrolytic solution

Methyl ethyl carbonate, diethyl carbonate, ethylene carbonate are mixed with volume ratio 3:1:2, in mixed solvent, dissolved LiPF ₆, making its concentration is 1.2mol/l, adds wherein tert-butyl benzene methyl ether (TBAN) 0.1 quality %, fluorobenzene ether (FB) 3 quality %, biphenyl (BP) 0.2 quality %, C ₄f ₉oCH ₃(HFE) 10 quality %, vinylene carbonate (VC) 3 quality %, prepare nonaqueous electrolytic solution.

The making of non-aqueous secondary batteries

By above-mentioned positive pole and negative pole across the barrier film formed by microporous polyethylene film [void content 53%, MD direction hot strength: 2.1 * 10 ⁸n/m ², TD direction hot strength: 0.28 * 10 ⁸n/m ²thickness 16 μ m, 80 seconds/100ml of air permeability, the percent thermal shrinkage 3% of the TD direction after 105 ℃ * 8 hours, puncture intensity: 3.5N (360g)] be wound into spirality, after making the electrode body of winding-structure, in order to insert the electrode body of pressurizeing to make the flat winding-structure in square battery case.In the rectangular cell case of the aluminium alloy system of being inserted into, carry out the welding of positive and negative lead wires body and the cover plate laser welding to the open end of battery case, inject above-mentioned nonaqueous electrolytic solution with the inlet of cover plate from being arranged on sealing in battery case, make nonaqueous electrolytic solution fully soak into barrier film etc., then, charged, maturation, there is the outward appearance shown in the structure shown in Fig. 1, Fig. 2, obtain wide 34.0mm, thickness 4.0mm, the height 50.0mm square non-aqueous secondary batteries.

Here, battery shown in Fig. 1 and Fig. 2 is described, positive pole 1 and negative pole 2 are as mentioned above after barrier film 3 is wound into spirality, the electrode duplexer 6 that pressurizes in order to become flat and obtain the flat winding-structure is accommodated in this electrode duplexer 6 in square battery case 4 together with nonaqueous electrolytic solution.But, in Fig. 1, for fear of miscellaneousization, the metal forming of the collector body used when making positive pole 1 and negative pole 2 and electrolyte etc. are not made diagram.

Battery case 4 is that this battery case 4 doubles as positive terminal with the case of the major part of the exterior material of aluminium alloy system formation battery.And, bottom at battery case 4, the insulator 5 that configuration consists of ptfe sheet, from the electrode duplexer 6 of the flat winding-structure that formed by above-mentioned anodal 1, negative pole 2 and barrier film 3, draw anodal 1 and each end of negative pole 2 on the positive wire body 7 and the negative wire body 8 that are connected.In addition, on the cover plate 9 of the aluminum of the peristome of sealed battery case 4, the terminal 11 of stainless steel is installed across the insulation-encapsulated 10 of polypropylene system, the lead plate 13 of stainless steel is installed across insulator 12 on this terminal 11.

And this cover plate 9 inserts the peristome of above-mentioned battery case 4, by welding both junction surfaces, the peristome of battery case 4 is sealed to enclosed cell inside.In addition, in the battery of Fig. 1, electrolyte inlet 14 is set on cover plate 9, this electrolyte inlet 14, to insert the state of containment member, fetch welded seal by for example Laser Welding, guarantee battery seal (thereby, in the battery of Fig. 1 and Fig. 2, in fact, electrolyte inlet 14 is electrolyte inlet and containment member, but, for easy explanation, as electrolyte inlet 14, means).In addition, in cover plate 9, explosionproof hole 15 is set.

In the battery of this embodiment 1, by positive wire body 7 is directly welded on cover plate 9, make battery case 4 and cover plate 9 as positive terminal performance function, negative wire body 8 is welded on lead plate 13, come conducting negative wire body 8 and terminal 11 by this lead plate 13, thereby make terminal 11 as negative terminal performance function, according to material of battery case 4 etc., its positive and negative can be contrary.

Fig. 2 is the oblique view of the outward appearance of the battery shown in presentation graphs 1 schematically, and this Fig. 2 is that this Fig. 2 schematically means battery, means specific member in the battery member of formation in order to mean that above-mentioned battery is rectangular cell and illustrated figure.

Embodiment 2

Except add tert-butyl benzene methyl ether (TBAN) 0.05 quality % in nonaqueous electrolytic solution, operation, make non-aqueous secondary batteries similarly to Example 1.

Embodiment 3

Except add tert-butyl benzene methyl ether (TBAN) 0.2 quality % in nonaqueous electrolytic solution, operation, make non-aqueous secondary batteries similarly to Example 1.

Embodiment 4

Except add tert-butyl benzene methyl ether (TBAN) 0.5 quality % in nonaqueous electrolytic solution, operation, make non-aqueous secondary batteries similarly to Example 1.

Embodiment 5

Except add tert-butyl benzene methyl ether (TBAN) 1 quality % in nonaqueous electrolytic solution, operation, make non-aqueous secondary batteries similarly to Example 1.

Embodiment 6

Not only add the tert-butyl benzene methyl ether in nonaqueous electrolytic solution, also add methyl phenyl ethers anisole (AN) 0.1 quality %, in addition, operation, make non-aqueous secondary batteries similarly to Example 1.

Embodiment 7

Not only add the tert-butyl benzene methyl ether in nonaqueous electrolytic solution, also add ethoxybenzene (EB) 0.1 quality %, in addition, operation, make non-aqueous secondary batteries similarly to Example 1.

Embodiment 8

By LiCo _0.9965mg _0.0014ti _0.0007al _0.0014o ₂(average grain diameter 8 μ m) are used separately as positive active material, and in addition, operation, make non-aqueous secondary batteries similarly to Example 1.The density of the anode mixture layer after pressurized treatments (anodal density) is 3.76g/cm ³.There is size frequency peak d in this positive active material on particle diameter 9.6 μ m _p, d ₁₀be 4 μ m, d ₉₀be 12.4 μ m, d _mbe 8.2 μ m, d _p/ d _mbe 1.2.

Embodiment 9

Except positive active material (B) is changed to LiCo _0.334ni _0.33mn _0.33mg _0.0024ti _0.0012al _0.0024o ₂(average grain diameter 5 μ m) in addition, operation, make non-aqueous secondary batteries similarly to Example 1.The density of the anode mixture layer after pressurized treatments (anodal density) is 3.72g/cm ³.In addition, about metallic element M ²content, positive active material (B), with respect to positive active material (A), take mole is benchmark, Mg is 3 times, Ti is 3 times, Al is 3 times.Size frequency peak d _pbe present in 12 μ m and 5 μ m, on the other hand, d ₁₀be 4.1 μ m, d ₉₀be 14.1 μ m, d _mbe 9.1 μ m.D _p/ d _mbe 1.3.

Comparative example 1

Except not to adding in nonaqueous electrolytic solution the tert-butyl benzene methyl ether, make similarly to Example 1 non-aqueous secondary batteries.

Comparative example 2

By regulating the pressurized treatments condition, the density that makes the anode mixture layer is 3.48/cm ³, in addition, operation, make non-aqueous secondary batteries similarly to Example 1.Regulate the both positive and negative polarity electrode long, make the diameter of electrode body identical.

Comparative example 3

Except add tert-butyl benzene methyl ether 5 quality % in nonaqueous electrolytic solution, operation, make non-aqueous secondary batteries similarly to Example 1.

Non-aqueous secondary batteries to embodiment 1～9 and comparative example 1～3, carry out following evaluating characteristics.

Discharge capacity after charge and discharge cycles

To each battery of embodiment 1～9 and comparative example 1～3, use the constant current charge of 0.2C to assigned voltage, carry out constant voltage charge until total charging time is 8 hours, then, carry out constant-current discharge with 0.2C, until cell voltage is 3.3V, obtain discharge capacity now.Cell voltage during above-mentioned constant current charge is 4.2V, two kinds of 4.4V (the lithium benchmark means the charging under 4.3V, 4.5V).Repeat to discharge and recharge for 5 times under identical therewith condition, the 5th is visited to the discharge capacity after capacitance is evaluated as charge and discharge cycles.Result is as shown in table 1, in these tables, is the relative value that the discharge capacity while take the charge and discharge cycles of battery of comparative example 1 is 100 o'clock, the discharge capacity after the charge and discharge cycles that means each battery is obtained.

Safety evaluatio

Each battery to embodiment 1～9 and comparative example 1～3, with the constant current charge of 0.2C to 4.4V, carry out constant voltage charge until total charging time is 8 hours, then, putting into thermostat is heated up with 5 ℃/min from room temperature, keep constant temperature under 150 ℃, to heating of battery 10 minutes, the temperature (surface temperature) of measuring each battery changed.The temperature that adds the battery of hankering is lower, and the fail safe while meaning high temperature is higher.Result is listed in table 1.

Table 1

From the result shown in table 1, the non-aqueous secondary batteries of embodiment is compared with the non-aqueous secondary batteries of comparative example, discharge capacity and excellent charge/discharge cycle characteristics, and the temperature during high-temperature storage of full charging or overcharge condition rises less, and fail safe is also good.In addition, use the portable set of these batteries, the capacity after circulation is large, and in addition, near the heating battery outer section of 150 ℃ is few, preferably as combination.Before this, benzyl ether compounds has when battery is overcharged, produce off-response and improve the known case of level of security, but, the fail safe under common charging voltage is improved, do not understand too many, even the common charging voltage of the present invention, also can find that the high-temperature storage at 150 ℃ produces effect, this can not easily analogize, and also is not easy and other aromatic series combination.

Claims

1. a non-aqueous secondary batteries, it possesses positive pole, negative pole and nonaqueous electrolyte, and described just having an anode mixture layer that contains positive active material, it is characterized in that:

As above-mentioned positive active material, the lithium-containing transition metal oxide that contains the crystal structure with stratiform, form the metallic element of above-mentioned lithium-containing transition metal oxide, at least one element and the Li selected from the group of Co, Ni and Mn formation of take is main body, and, contain at least one element of selecting the group formed from Mg, Ti, Zr, Ge, Nb, Al and Sn

As positive active material, use the different lithium-containing transition metal oxide of more than two kinds of average grain diameter,

In above-mentioned lithium-containing transition metal oxide of more than two kinds, the material with minimum average grain diameter is the compound meaned with following general formula (1), and has the metallic element M of the positive active material B of minimum average grain diameter ²content than the M of the lithium-containing transition metal oxide beyond positive active material B ²content many,

The density of above-mentioned anode mixture layer is 3.5g/cm ³it is above,

Above-mentioned nonaqueous electrolyte contains the aromatic compound with alkoxyl with the scope below 3 quality % more than 0.02 quality %, and described alkoxyl has the alkyl of the straight or branched of carbon number 1～4,

Li _xM ¹ _yM ² _zM ³ _vO ₂ (1)

Here, in above-mentioned general formula (1), M ¹at least one transition metal among Co, Ni or Mn, M ²at least one metallic element of selecting the group formed from Mg, Ti, Zr, Ge, Nb, Al and Sn, M ³li, M ¹and M ²element in addition, and, 0.97≤x<1.02,0.8≤y<1.02,0.002≤z≤0.05,0≤v≤0.05.

2. non-aqueous secondary batteries according to claim 1, is characterized in that, the above-mentioned aromatic compound with alkoxyl is the methyl phenyl ethers anisole or derivatives thereof.

3. non-aqueous secondary batteries according to claim 1 and 2, is characterized in that, in the size distribution curve of positive active material, and d ₅₀value be greater than d ₁₀value and d ₉₀the arithmetic mean of value.

4. non-aqueous secondary batteries according to claim 1, is characterized in that, in above-mentioned lithium-containing transition metal oxide of more than two kinds, the lithium-containing transition metal oxide with maximum average grain diameter, be the compound meaned with following general formula (2),

Li _aM ¹ _bM ² _cM ³ _dO ₂ (2)

Here, in above-mentioned general formula (2), M ¹, M ²and M ³identical with above-mentioned general formula (1), and 0.97≤a<1.02,0.8≤b<1.02,0≤c≤0.02,0≤d≤0.02.

5. non-aqueous secondary batteries according to claim 4, is characterized in that, z is c more than 1.5 times.