CN100429812C - Positive electrode material for non-aqueous electrolyte lithium ion battery and battery using the same - Google Patents

Abstract

A positive electrode material for non-aqueous electrolyte lithium ion battery(31, 41) of the present invention has an oxide(11) containing lithium and nickel, and a lithium compound(13) which is deposited on a surface of the oxide(11) and covers nickel present on the surface of the oxide (11). By this structure, it is possible to suppress decomposition of an electrolysis solution as much as possible and drastically reduce swelling of the batteries(31, 41).

Description

The positive electrode of lithium ion battery with nonaqueous electrolyte and adopt its battery

Technical field

The present invention relates to lithium nickel oxide (Li-Ni oxide) is the positive electrode of nonaqueous electrolyte (non-aqueous electrolyte) lithium ion battery of positive active material, and relates to the lithium ion battery with nonaqueous electrolyte that adopts this positive electrode.

Background technology

At present, as the rechargeable nonaqueous electrolytic battery that is used for such as portable sets such as mobile phones, lithium rechargeable battery is commercialization.Along with the weight of portable set and the reduction of thickness, aqueous electrolyte lithium ion secondary batteries itself needs thinner.Recently, developed and adopted the thin battery of laminate film as sheathing material, and the lamination-type thin battery drops into practicality, wherein positive active material is lithium and cobalt oxides (LiCoO ₂), negative electrode active material is graphite material or material with carbon element, and nonaqueous electrolyte is lithium salts or the polymer dielectric that is dissolved in the organic solvent.

In addition, in recent years, along with the increase of portable set function and the enhancing of performance, the power consumption of equipment increases day by day.Need improve capacity as the battery of its power supply strongly.Therefore, developing the Li-Ni oxide (LiNiO of the conventional lithium of expection Capacity Ratio-cobalt oxidation object height ₂, Li _xNi _1-a-bCo _aAl _bO ₂).

In recent years, except this class is used, in order to resist the popularization of electric automobile (EV), hybrid-electric car (HEV) and the fuel cell car (FCV) of serious environmental trend promotion day by day, developing automobile and driving the power supply of using, complementary AC-battery power source etc.Use the aqueous electrolyte lithium ion secondary batteries that use can repeated charge for this class.In fact application for resembling high output such as the needs that are used for EV, HEV, FCV and high-energy-density can not prepare single macrocell, the general battery pack that is made of a plurality of series connected battery of using.As the battery that constitutes this battery pack, proposed to use the thin lithium ion battery with nonaqueous electrolyte (only being called thin laminate batteries) of lamination-type.

In the thin laminate batteries in high output of needs and high-energy-density application, use the case member of metal sheet as battery.The case member of this thin laminate batteries is seen as rectangle and has predetermined flat pattern from the top.

Thin laminate batteries is in light weight, because thin laminate batteries does not have metal container separately.And, when overcharging etc. and the container inner high voltage that causes cause when breaking, impulsive force is also little than the impulsive force in the canister.Therefore, thin laminate batteries needing to be suitable for the application of high output and high-energy-density, as is used for the automobile driving application of EV, HEV and FCV.

Moreover, the same with the situation of portable set as described above in this thin laminate batteries, the requirement that improves capacity is further strengthened.Therefore, developing the high Li-Ni oxide of the conventional lithium and cobalt oxides of expection Capacity Ratio.

Yet, use comprises the Li-Ni battery of this Li-Ni oxide as the positive electrode (only being called the Li-Ni positive electrode) of positive active material, has oxonium ion and is oxidized to oxygen radical by the high price nickel ion in the positive electrode and discharges this oxygen radical and then make the problem of electrolyte decomposition.When initial charging or when at high temperature storing, adopt in the battery of this positive electrode and produce a large amount of gas, battery seriously expands.

In order to solve foregoing problems, a day disclosure special permission communique 2002-203552 discloses a kind of pH by the control positive electrode and suppresses the method that gas produces.

Summary of the invention

Yet in the described method of aforementioned documents, positive active material is that the co-precipitation by the hydroxide raw material obtains, and hydroxyl keeps from the teeth outwards.This method suppresses free radical by being retained in lip-deep hydroxyl, but only is effective when moisture enters battery.This method can not play a role in charging and discharge well at high temperature (60 ℃ or higher) and high-voltage state (charged state), even when suppressing the alkalescent of material by control pH.In other words, in high-voltage state, this composition (constitution) can not play a role effectively, carries out naturally because react under high-voltage state and high temperature, and produces gas.

The present invention finishes according to aforesaid routine techniques, the purpose of this invention is to provide the positive electrode that lithium ion battery with nonaqueous electrolyte is used, even it also can suppress the decomposition of electrolyte when storing in battery charge or under high temperature.In addition, the purpose of this invention is to provide the battery that adopts this positive electrode, couple together the battery pack that constitutes by a plurality of these batteries, and their vehicle (vehicle) is housed.

The positive electrode that first aspect of the present invention provides lithium ion battery with nonaqueous electrolyte to use, it comprises: the oxide that contains lithium and nickel; And being deposited on lithium compound on this oxide surface, this lithium compound covers the nickel that exists on this oxide surface.

A second aspect of the present invention provides lithium ion battery with nonaqueous electrolyte, and it comprises positive electrode, and this positive electrode comprises: the oxide that contains lithium and nickel; And being deposited on lithium compound on this oxide surface, this lithium compound covers the nickel that exists on this oxide surface.

A third aspect of the present invention provides battery pack (assembled battery), and this battery pack comprises a plurality of lithium ion battery with nonaqueous electrolyte, and each lithium ion battery with nonaqueous electrolyte comprises positive electrode, and this positive electrode has: the oxide that contains lithium and nickel; And be deposited on lithium compound on this oxide surface, and this lithium compound covers the nickel that exists on this oxide surface, and wherein said lithium ion battery connects in the mode of serial or parallel connection and installs.

A fourth aspect of the present invention provides combined assembled battery (combined assembled battery), this combined assembled battery comprises a plurality of battery pack, each battery pack comprises a plurality of lithium ion battery with nonaqueous electrolyte, each lithium ion battery with nonaqueous electrolyte comprises positive electrode, and this positive electrode has: the oxide that contains lithium and nickel; And be deposited on lithium compound on this oxide surface, and this lithium compound covers the nickel that exists on this oxide surface, and wherein said lithium ion battery connects in the mode of serial or parallel connection and installs.

Description of drawings

Fig. 1 is the sectional view with the particle that covers its surperficial Li compound of used Li-Ni oxide and deposition in the positive electrode of the present invention;

Fig. 2 is the schematic diagram with the particle that covers its surperficial Li compound of used Li-Ni oxide and deposition in the positive electrode of the present invention;

The schematic cross-section of the ambipolar lithium rechargeable battery of Fig. 3 right and wrong;

Fig. 4 is the schematic cross-section of ambipolar lithium rechargeable battery;

Fig. 5 A is the plane graph that adopts the battery pack of lithium rechargeable battery of the present invention;

Fig. 5 B is the front view that adopts the battery pack of lithium rechargeable battery of the present invention;

Fig. 5 C is the end view that adopts the battery pack of lithium rechargeable battery of the present invention;

Fig. 6 A adopts the plane graph of another example of the battery pack of lithium rechargeable battery of the present invention;

Fig. 6 B adopts the front view of another example of the battery pack of lithium rechargeable battery of the present invention;

Fig. 6 C adopts the end view of another example of the battery pack of lithium rechargeable battery of the present invention;

Fig. 7 A is the plane graph that adopts the combined assembled battery of lithium rechargeable battery of the present invention;

Fig. 7 B is the front view that adopts the combined assembled battery of lithium rechargeable battery of the present invention;

Fig. 7 C is the end view that adopts the combined assembled battery of lithium rechargeable battery of the present invention;

Fig. 8 is the schematic diagram that the vehicle of lithium rechargeable battery of the present invention is installed on it;

Fig. 9 is a figure of explaining absolute maximum length used in the particle diameter measurement; And

Embodiment

Embodiment of the present invention are described below with reference to accompanying drawings, the feature that wherein same digitized representation is same.

Positive electrode according to lithium ion battery with nonaqueous electrolyte of the present invention comprises the lithium-nickel oxide that deposits lithium compound on its surface.The feature of this lithium compound is to cover to be present in the lip-deep nickel of lithium-nickel oxide, makes nickel not be exposed in the surface of oxide as much as possible.The generation that this has stoped the oxygen radical that causes because of the nickel ion that exists on the surface produces gas and minimizes.

This oxide the Li-Ni oxide that can be used in the positive electrode of the present invention do not had concrete restriction, as long as can be used as positive active material.The Li-Ni oxide comprises lithium-Ni-based composite oxides of mainly being made up of lithium and nickel.As the Li-Ni oxide, except LiNiO ₂Outside, the Li-Ni complex oxide that also can use the part of nickel metal to be replaced, for example LiNi by elements such as other transition metal _xCo _1-xO ₂(0＜x＜1), below the lithium-Ni-based composite oxides shown in the formula I:

Li _aNi _bCo _cMn _dMeO _2-x-yN _yFormula I

0≤a in the formula≤1.2,0.3≤b≤0.85,0≤c≤0.4,0≤d≤0.6,0≤e≤0.1,0.9≤b+c+d≤1.2 ,-0.05≤x≤0.1, and 0≤y≤0.05; M is Al, Mg, Ca, Ti, V, Cr, Fe, and Ga at least a; And N is F, Cl, and at least a among the S.

The composition of these Li-Ni complex oxides can be measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), atomic absorption method, fluorescent X-ray method, particle analyzer etc.

In view of higher capacity, reactivity and cyclic durability (cycle endurance) as the Li-Ni oxide of positive active material, the average diameter of wishing the Li-Ni oxide particle of aforementioned positive active material is 0.1～20 μ m.When the Li-Ni oxide formed secondary, the average diameter that expectation constitutes the primary granule of secondary was 0.01～5 μ m.Yet the Li-Ni oxide needn't necessarily form secondary by assembling or reuniting.The diameter of Li-Ni oxide particle and the diameter of primary particle can pass through, and for example, scanning electron microscopy (SEM) or transmission electron microscope (TEM) are measured.The Li-Ni oxide that deposits the Li compound on Li-Ni oxide and its can take on a different shape, and this depends on its type and preparation method etc., and spherical in shape, sheet shape, aciculiform, cylindricality, piece shape etc.Can use the Any shape in these shapes without difficulty.It is desirable to, suitably choose the optimum shape that can improve battery performance (as charge/discharge characteristics).The diameter of aforesaid Li-Ni oxide particle is represented with absolute maximum length (absolutemaximum length), because coating of particles is inhomogeneous.Here, absolute maximum length as shown in Figure 9, is meant the upward maximum length L of the distance between any 2 of particle 91 contours (contour).

Secondly, as the Li compound that is deposited on the aforementioned Li-Ni oxide surface, preferably include the compound of Li ionic conductivity.Li ionic conduction compound has low internal resistance increase by covering (covering) or spraying (sprinkling) when depositing.On the contrary, for the compound that does not have the Li ionic conductivity, the part of deposition plays resistance.Therefore, battery performance can be affected, although it can suppress the decomposition of electrolyte and stop expand (purpose of the present invention).So, in the present invention, preferred Li-ionic conduction compound.It is desirable to, this Li compound is to be selected from least a in following: lithium phosphate, nitrogen phosphorous oxide lithium (LiPON), Li ₂O-B ₂O ₃Compound, Li ₂O-B ₂O ₃-LiI compound, Li ₂O-SiS ₂Compound, Li ₂S-SiS ₂-Li ₃PO ₄Compound, cobalt acid lithium (lithium cobaltate), LiMn2O4, LiFeO ₄, and lithium hydroxide.Except these, can also use lithium acetate, ethinylation lithium-ethylenediamine complex compound, lithium benzoate, lithium carbonate, lithium fluoride, lithium oxalate, pyruvic acid lithium, lithium stearate, lithium tartrate, lithium bromide, lithium iodide, Li ₂S-SiS ₂, lithium sulfate, or the like.These compounds can use separately or use with the form of its two or more mixture.The composition of these Li compounds can be measured by ICP, atomic absorption method, fluorescent X-ray method, particle analyzer etc.

As mentioned above, preferred aforesaid Li compound is a Li-ionic conduction compound, and particularly the Li-ionic conductivity is not less than 10 ^-15Sm ^-1, preferably be not less than 10 ^-12Sm ^-1Compound.The Li-ionic conductivity can be measured by AC impedance method, permanent electromotive force step-by-step method, constant current step-by-step method etc.

Aforesaid Li compound only needs to be deposited on the surface of Li-Ni oxide.Especially, as shown in Figure 1, Li compound 13 can deposit with on the surface that covers Li-Ni oxide 11, and perhaps as shown in Figure 2, Li compound 13 can deposit to spray on the surface of Li-Ni oxide.Here, the surface of Li-Ni oxide is the surface of the particle of Li-Ni oxide, as shown in FIG..If the Li-Ni oxide forms secondary, then the surface of Li-Ni oxide can be the surface of primary particle, the surface of the secondary that is made of the primary particle of assembling, the perhaps surface of these two kinds of particles.In other words, the Li compound only need be deposited at least on any of secondary or primary particle.Fig. 1 and Fig. 2 show the example of secondary, and the deposition of Li compound schematically shows in the time of still can seeing the Li-Ni oxide 11 replacement primary particles in the mapping.

At first, just by covering and spraying and adhere to (attachment) to Effect on Performance, the expansion that covers battery provides preferable performance (seeing Table 1～4).This is because when the Li-Ni oxide surface is coated with the Li compound fully, just no longer sent oxygen radical in electrolyte.On the other hand, when the Li compound sprays at the Li-Ni oxide surface, also send some oxygen radicals.

Just deposit Effect on Performance by covering and spraying, the increase of spraying internal resistance provides preferable performance (seeing Table 1～4).This be because, when the Li-Ni oxide surface is coated with the Li compound fully, just do not exist from the Li ion of electrolyte can be with it direct reacted surface, thereby increased resistance.Yet when not having the Li compound on the Li-Ni oxide surface, Comparative Examples described as follows is such, not only can not suppress the expansion of battery, and Li-Ni oxide surface and electrolyte reacts to each other, and resistance is increased.

In the lip-deep method of lithium-nickel oxide, wet method and dry method can be used as for deposition Li compound.In the wet method in these methods,, then carry out co-precipitation, thermal decomposition and cure if the Li-Ni oxide by prepared by co-precipitation, then mixed the raw material of Li compound with the Li-Ni oxide before co-precipitation.On the other hand, in dry method, the Li compound is mixed with the positive active material for preparing by above-mentioned wet method, rather than mix the Li compound and mix to do.This mixing can utilize any method or equipment as (the NARA MACHINARY CO. of the system of blending together, LTD.), COSMOS (KawasakiHeavy Industries, Ltd.), machinery merges (Hosokawa Micron), (the NipponPneumatic Mfg of Surfusing system, CO., Ltd.), (OKADA SEIKO CO. TD.) carries out to reach Mechanomill, Speed kneader, Speed mill and spiracoater.If desired, can heat products therefrom subsequently.Can obtain depositing on its surface the Li-Ni oxide of Li compound thus.

When deposition Li compound 13 when covering Li-Ni oxide 11 surperficial, as shown in Figure 1, it is desirable to, the tectal thickness of Li compound is 5nm to 1 μ m, is preferably 50nm to 1 μ m, more preferably 70～700nm.Produce oxygen radical if tectal thickness less than 5nm, often is difficult to suppress fully the Li-Ni oxide, make to be difficult to stop fully the decomposition of electrolyte.On the other hand, if tectal thickness greater than 1 μ m, then resistance increases, although the Li compound has the Li-ionic conductivity, this may influence the high response of positive active material.Tectal thickness can observe the cross section of particle measure by TEM.

When deposition Li compound 13 when spraying on the surface of Li-Ni oxide 11, as shown in Figure 2, it is desirable to, the volume of supposing positive active material is 100, then the volume of Li compound is 0.5～10, is preferably 0.7～7.When with respect to the volume that is set at 100 positive active material, the volume of Li compound was less than 0.5 o'clock, the Li compound that can spray on the Li-Ni oxide surface is limited, thereby the Li compound often is difficult to play a role and produces oxygen radical to suppress the Li-Ni oxide fully.On the other hand, when with respect to the volume that is set at 100 positive active material, the volume of Li compound is greater than 10 o'clock, and the Li compound has covered the whole surface of Li-Ni oxide and has been difficult on substantially and sprayed.In addition, the amount of the Li compound that does not directly relate in the reaction increases, and this may influence the high response of positive active material, although the Li compound has the Li-ionic conductivity.The amount of Li compound is based on the volume that is made as 100 positive active material, but in practice, consider in order to prevent to produce oxygen radical in the Li-Ni oxide as positive active material, the volume that the Li-Ni oxide more preferably is set is 100, and based on this.In particular, preferablely be that with respect to the volume that is set at 100 Li-Ni oxide, the volume of Li compound is 0.5～10, is preferably 0.8～8.The volume of Li compound can be observed by SEM, TEM observation etc. measured.

The positive electrode that is used for lithium ion battery of the present invention only need comprise the Li-Ni oxide that deposits the Li compound on aforesaid its surface.In addition, if desired, this positive electrode can also at random comprise other positive electrode.Below these materials will be described.

Other material that can be used in the positive electrode of the present invention can be the electric conducting material that increases electron conduction, binding agent, increase the support salt (supporting salts) (lithium salts) of ionic conductivity, gel-form solid polymer electrolyte or solid electrolyte (matrix polymer, electrolyte etc.), or the like.When using gel-form solid polymer electrolyte in the dielectric substrate between both positive and negative polarity, should comprise binding agent, electric conducting material etc., but needn't necessarily comprise electrolyte, lithium salts etc.If use the electrolyte of solution form in the dielectric substrate, then needn't necessarily comprise matrix polymer, electrolyte, lithium salts etc. in the positive electrode.

Aforesaid electric conducting material is the carbon fiber (VGCF) of acetylene black, carbon black, graphite, vapor phase growth etc.Aforesaid binding agent can be polyvinylidene fluoride (PVDF), butadiene-styrene rubber (SBR), polyimides etc.

Aforesaid gel-form solid polymer electrolyte is the solid polymer electrolyte that contains the ionic conduction of used electrolyte in the lithium ion battery with nonaqueous electrolyte, perhaps for maintaining the polymer that does not have lithium ion conductive of identical electrolyte in its skeleton.

Here, for the support salt of the electrolyte that is comprised in the gel-form solid polymer electrolyte, can use the lithium salts (support salt) of at least a type, this lithium salts is selected from inorganic anion salt such as LiPF ₆, LiBF ₄, LiClO ₄, LiAsF ₆, LiTaF ₆, LiAlCl ₄, and Li ₂B ₁₀Cl ₁₀And organic anion salt such as LiCF ₃SO ₃, Li (CF ₃SO ₂) ₂N, and Li (C ₂F ₅SO ₂) ₂N.For the plasticizer of electrolyte, can use aprotic solvent etc., it is to be selected from least a in following or two or more mixture: cyclic carbonate, as propylene glycol carbonate, and the ethylene carbonate ester; Non-annularity carbonic ester such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; Ether, as oxolane, the 2-methyltetrahydrofuran, 1, the 4-dioxane, 1, the 2-dimethoxy-ethane, and 1,2-dibutoxy ethane; Lactone is as gamma-butyrolacton; Nitrile is as acetonitrile; Ester is as methyl propionate; Acid amides is as dimethyl formamide; Methyl acetate; And methyl formate.

For the solid polymer electrolyte of ionic conduction, for example, can use poly(ethylene oxide) (PEO), PPOX (PPO), and copolymer.

For the used polymer that does not have lithium ion conductive in the gel-form solid polymer electrolyte, can use, for example, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA) etc.It is more suitable that PAN, PMMA etc. list low ionic conductivity classification in.PAN, PMMA etc. can be considered aforesaid ionic-conductive polymer, but in this article as the example of the polymer that does not have lithium ion conductive used in the gel-form solid polymer electrolyte.

Support salt for increasing ionic conductivity can use, for example, and inorganic anion salt such as LiPF ₆, LiBF ₄, LiClO ₄, LiAsF ₆, LiTaF ₆, LiAlCl ₄, and Li ₂B ₁₀Cl ₁₀And organic anion salt such as LiCF ₃SO ₃, Li (CF ₃SO ₂) ₂N, and Li (C ₂F ₅SO ₂) ₂N; And their mixture.

Gel-form solid polymer electrolyte mesostroma polymer and electrolytical mass ratio can determine that particularly, the preferred mass ratio is 2/98 to 90/100 according to predetermined purposes.In other words, consider to prevent that electrolyte from being decomposed by the oxygen radical that the Li-Ni oxide is sent that the present invention acts on the electrolyte (electrolyte) or the gel-form solid polymer electrolyte of the solution form in the nonaqueous electrolyte especially effectively.Thereby, with regard to gel-form solid polymer electrolyte mesostroma polymer and electrolytical mass ratio, the cell expansion that needn't cause and limit the amount of electrolyte for the decomposition that prevents electrolyte, and should pay the utmost attention to battery performance.

Except the Li-Ni oxide, deposit the amount of Li-Ni oxide, positive active material, electric conducting material, binding agent, polymer dielectric (matrix polymer, electrolyte etc.) and the lithium salts of Li compound on its surface, should take the intended purpose (output consciousness, energy consciousness etc.) and the ionic conductivity of battery into account and determine.

Positive electrode of the present invention can be widely used in lithium ion battery with nonaqueous electrolyte.Especially, this positive pole can be realized high-energy-density and high output density, and can stably be used for the driving power of vehicle.In addition, this positive electrode can be applied to the rechargeable nonaqueous electrolytic battery of portable set such as mobile phone fully.The following describes the aqueous electrolyte lithium ion secondary batteries that comprises positive electrode of the present invention.

Lithium ion battery as target of the present invention only need comprise positive electrode of the present invention, need not other component is limited.For example, when distinguishing lithium ion battery according to occupation mode, aforesaid lithium ion battery can be applicable to any type of primary cell and secondary cell.When according to shape and structure differentiation lithium ion battery, aforesaid lithium ion battery can be applicable to any cascade type (pancake) battery, convoluted (cylindrical) battery etc.From the electric connection mode of inside lithium ion cell, lithium ion battery can be applicable to any bipolar cell and non-bipolar cell.About bipolar cell, can make up big, the output performance battery more excellent of single battery voltage and Capacity Ratio common batteries than common batteries.Because polymer battery does not cause leak of liquid, so polymer battery does not exist the problem and the reliability height of liquid junctions.And polymer battery has the advantage that can form the non-aqueous electrolyte battery with excellent output performance in simple structure.Moreover, adopt stepped construction, allow to guarantee long-term reliability, and be favourable aspect cost and the machinability by simple Sealing Technology such as hot binding.

Bipolar or the non-bipolar aqueous electrolyte lithium ion secondary batteries of each self-contained positive electrode of the present invention is described with reference to the accompanying drawings.

Fig. 3 shows the non-bipolar aqueous electrolyte lithium ion secondary batteries 31 of cascade type.In this lithium rechargeable battery 31, use the laminate film that constitutes by polymer and metallic combination as battery sheath 32, and the whole periphery of battery sheath 32 engage by heat-sealing, with sealed electrical power generating device 38.Electrical power generating device 38 comprises positive plate and the negative plate that piles up mutually.In each positive plate, positive electrode active material layer 34 is formed on the both sides of positive electrode collector 33.In each negative plate, negative electrode active material layer 37 is formed on the both sides of negative electrode collector 36.The positive wire 39 and the negative wire 40 that are electrically connected with aforementioned positive plate and negative plate by ultrasonic bonding, impedance welding etc., are connected on positive electrode collector 33 and the negative electrode collector 36.Positive wire 39 and negative wire 40 are clipped between the thermal weld part 32a, and are exposed to the outside of battery sheath 32.

Fig. 4 shows the complete structure of ambipolar nonaqueous lithium ion secondary cell (bipolar cell).Bipolar cell 41 comprises electrical power generating device 47, it has the structure that a plurality of bipolar electrodes 45 pile up mutually, and dielectric substrate 46 is mediate: each bipolar electrode comprises positive electrode active material layer 43 that is positioned at collector body 42 1 sides and the negative electrode active material layer 44 that is positioned at collector body 42 opposite sides.The electrode 45a and the 45b that are positioned at electrical power generating device 47 the superiors and the bottom needn't have bipolar electrode configurations, and it can have positive electrode active material layer 43 or negative electrode active material layer 44 and be arranged in structure on the collector body 42.In bipolar cell 41, positive wire 48 links to each other with collector body 42 in top and bottom respectively with negative wire 49.

The number of the bipolar electrode 45 that piles up (comprising electrode 45a, 45b) can be adjusted according to required voltage.In bipolar cell 41,, then can reduce the number of the bipolar electrode 45 that piles up if even under the situation that reduces cell thickness as far as possible, still can guarantee enough output.In bipolar cell 41 of the present invention, external impact and environmental degradation in preventing to use preferably under reduced pressure are sealed in electrical power generating device 47 in the battery sheath 50 48,49 outsides that are exposed to battery sheath 50 of contact conductor.The basic structure of this bipolar cell 41 is structures that a plurality of element cells that pile up are one another in series.This ambipolar aqueous electrolyte lithium ion secondary batteries is identical with aforesaid non-ambipolar aqueous electrolyte lithium ion secondary batteries basically, and just its electrode structure difference will illustrate each part below together.

(collector body)

For can be used for collector body of the present invention, can preferably use the composite material of composite material, SUS and aluminium of composite material (clad material), copper and aluminium of aluminium foil, stainless steel foil (SUS), nickel and aluminium and the coating material (plated material) of these metallic combinations.Collector body can be made of the metal of surperficial aluminizing.In some cases, can use the collector body of the metal forming that comprises that two or more are bonded to each other.Under the situation of using composite collector, the example that is used as the material of positive electrode collector can be metal such as aluminium, aluminium alloy, SUS and the titanium of conduction, preferred especially aluminium.On the other hand, the example of the material of negative electrode collector can be material such as copper, nickel, silver and the SUS of conduction, preferred especially SUS, nickel etc.In composite collector, collector body only needs directly to be electrically connected each other or to be electrically connected to each other by the conductive intermediate layer of being made by the 3rd material.Except sheet material, anodal and negative electrode collector also can be made of glazing bar plate (lath plate) separately.The glazing bar plate comprises mesh space, and it is to have on it sheet material of otch to form by extending.

Thickness to collector body does not have concrete restriction, it typically is about 1～100 μ m.

(positive electrode active material layer)

The feature that constitutes the material of positive electrode active material layer is to adopt positive electrode of the present invention, and has described.Here omitted explanation to it.

The thickness of positive electrode active material does not have concrete restriction, and it should be determined according to the intended purpose (output consciousness, energy consciousness etc.) and the ionic conductivity of battery.The thickness of general positive electrode active material layer is about 1～500 μ m, and this scope can be applied to the present invention equally fully.Yet in order to show the function of positive electrode of the present invention effectively, preferred especially its thickness is 4～60 μ m.

(negative electrode active material layer)

Negative electrode active material layer comprises negative electrode active material.Support salt (lithium salts), gel-form solid polymer electrolyte or the solid electrolyte (matrix polymer, electrolyte etc.) etc. that in addition, also can comprise the electric conducting material that increases electron conduction, binding agent, increase ionic conductivity.Except the type of negative electrode active material, these are identical with described in the positive electrode chapters and sections of the present invention basically, and omitted relevant their explanation.

For negative electrode active material, preferably use at least aly to be selected from following material as main material: native graphite, Delanium, amorphous carbon, coke, mesophase pitch-base carbon fibre, graphite, and as the hard carbon of amorphous carbon.In addition, can also use metal oxide (especially transition metal oxide, particularly titanium oxide), the composite oxides of metal (especially transition metal, particularly titanium) and lithium, or the like.

(non-aqueous electrolyte layer)

In the present invention, according to predetermined purposes, can use (a) wherein infiltrate has the dividing plate of electrolyte, and (b) gel-form solid polymer electrolyte reaches any in (c) solid polymer electrolyte.

(a) infiltration has the dividing plate of electrolyte

For the electrolyte that can be infiltrated up in the dividing plate, can use with gel-form solid polymer electrolyte in the identical electrolyte (electrolytic salt and plasticizer) of electrolyte that comprised, described gel-form solid polymer electrolyte was described at positive electrode chapters and sections of the present invention.Clearly, preferably use LiClO ₄, LiAsF ₆, LiPF ₅, LiBOB, LiCF ₃SO ₃And Li (CF ₃SO ₂) ₂In at least a as electrolytic salt, and preferably use ethylene carbonate ester (EC), propylene glycol carbonate, diethyl carbonate (DEC), dimethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxy-ethane, 1,2-diethoxyethane, oxolane, 1, at least a in 3-dioxolanes and the gamma-butyrolacton as plasticizer.The concentration of preferred use electrolytic salt is regulated to the electrolyte of 0.5～2 mol, and it is to regulate and control in above-mentioned plasticizer by dissolving above-mentioned electrolytic salt.

For aforesaid dividing plate, can use by absorbing and keep the porous plate that the polymer of above-mentioned electrolyte makes (as polyolefin-Ji microporosity separator etc.), nonwoven fabric separator etc.Polyolefin-Ji microporosity separator to organic solvent has chemical stability has good effect to keeping with the hypoergia of electrolyte.

The material of described porous plate such as polyolefin-Ji microporosity separator is polyethylene (PE), polypropylene (PP), the laminated body with PP/PE/PP three-decker, polyimides etc.

The material of nonwoven fabric separator is cotton, staple fibre, acetic acid esters, nylon, polyester, polypropylene, polyolefin such as polyethylene, polyimides, aromatic polyamides etc., according to predetermined purposes (mechanical strength that dielectric substrate is required), these materials can be used alone or in combination.

The bulk density of non-woven fleece only needs so to set, and makes the gel-form solid polymer electrolyte of infiltration that sufficient battery performance is provided.Clearly, when the bulk density of non-woven fleece was excessive, the ratio of nonaqueous electrolyte material was excessive in the dielectric substrate, and the ionic conductivity in the dielectric substrate may reduce.

The thickness of dividing plate can change along with application, need not to define uniquely, for for the application of battery car (EV), hybrid-electric car (HEV) etc., is preferably 5～200 μ m.Dividing plate with this thickness range can be kept the performance of fixed electrolyte, and can suppress the increase of resistance.In addition, the short circuit that fine particle caused of preferred above-mentioned scope when preventing to cut into dividing plate, preferably this scope is desirable because dwindle interelectrode distance for height output also.Under the situation that connects a plurality of batteries, the area of electrode increases, and has strengthened the reliability of battery, the preferred dividing plate with maximum ga(u)ge that uses in above-mentioned scope.

The diameter of the micropore of preferred separator (particularly polyolefin-Ji microporosity separator) is not more than 1 μ m.The average dividing plate of micro-pore diameter in above-mentioned scope promptly causes " closing phenomenon ", and promptly dividing plate melts because be heated, and then closes micropore.This has strengthened the reliability under abnormal conditions, so thermal endurance is improved.Clearly, when battery temperature raise because of overcharging, dividing plate melted by heat and then " the closing phenomenon " of closing micropore were taken place rapidly.This prevents that the Li ion from arriving negative pole one side through dividing plate from an anodal side, and battery can not charge further.Thereby battery can not overcharged, and then elimination is overcharged.Therefore, battery security is improved, and can prevent that the heat sealing part of battery sheath from opening because of the gas that is produced.Here, the average diameter of the micropore of dividing plate is to calculate in the mode of average diameter, and way is by observation such as scanning electron microscopy dividing plate, and utilizes comparison film such as image analyzer to carry out statistical disposition.

The porosity of preferred polyolefm-Ji microporosity separator is 20～50%.When the porosity of dividing plate is in above-mentioned scope, reduce and prevent to penetrate the short circuit aspect that fine particle caused in the hole in the dividing plate from the output that resistance caused that prevents electrolyte, can guarantee output and reliability the two.Here, the porosity of dividing plate is meant the value by the volume ratio that obtains as the density of the resin of raw material with as the density of the dividing plate of end product.

The porosity of preferred nonwoven fabric separator is 50～90%.When porosity less than 50% the time, the performance of fixed electrolyte reduces, and when porosity greater than 90% the time, insufficient strength.

With regard to the amount of the electrolyte in being infiltrated up to aforementioned barriers, electrolyte should be infiltrated up to liquid and keep capacity, exceeds liquid maintenance capacity but also can be infiltrated up to.This be because by injecting resin to the electrolyte sealability part, can prevent that electrolyte from overflowing in dielectric substrate, and electrolyte can be infiltrated up to the degree that dielectric substrate nearly can keep.After the vacuum-injection process injection, electrolyte can keep by sealing fully.

(b) gel-form solid polymer electrolyte and (c) solid polymer electrolyte

For gel-form solid polymer electrolyte and solid polymer electrolyte, it is identical with gel-form solid polymer electrolyte and the solid polymer electrolyte described in the positive electrode chapters and sections of the present invention, omits relevant their explanation at this.

In single battery, can use the dielectric substrate of above-mentioned (a)～(c) together.

Polymer dielectric can be contained in gel-form solid polymer electrolyte layer, positive electrode active material layer and the negative electrode active material layer.In each layer, can use identical polymer dielectric, also can use different polymer dielectrics.

The matrix polymer of the gel-form solid polymer electrolyte that preferably uses is polyethers-based polyalcohol such as PEO and PPO at present.Thereby the non-oxidizability of an anodal side under hot conditions is little.If use the positive electrode with high oxidation reduction potentiality, the capacity of preferred negative pole is less than the capacity that is furnished with the positive pole of high gel electrolyte layer therebetween on the other side.When the capacity of negative pole during, can prevent that anodal electromotive force from exceedingly raising at the charging end less than the capacity of positive pole on the other side.Capacity anodal and negative pole can calculate by making creating conditions in anodal and the negative pole process, as theoretical capacity.Can utilize measuring equipment directly to measure the capacity of end product.Yet when the capacity of negative pole during less than the capacity of positive pole on the other side, the electromotive force of negative pole may exceedingly descend, and reduces the durability of battery, therefore need be careful charge/discharge voltage.Should be noted that to be the eigenvalue (proper value) of the redox potential of used positive active material for example, can not reduce durability by the average charging tension that battery is set.

Thickness to the dielectric substrate that constitutes battery does not have concrete restriction.Yet,, preferably reduce its thickness as much as possible to guaranteeing its degree as electrolytical function in order to obtain compact battery.The thickness of preferred electrolyte layer is 5～200 μ m.

(insulating barrier)

Insulating barrier is mainly used in bipolar cell.This insulating barrier be formed at each electrode around, be in contact with one another to prevent collector body adjacent in the battery, and prevent the short circuit that a little scrambling because of electrode tip causes.In the present invention, can around electrode, provide insulating barrier as required.Under the situation of utilizing battery as vehicle drive power or accessory power supply, need thoroughly prevent short circuit (liquid junctions) because of electrolyte causes.And battery will stand vibration for a long time and impact.From improving battery life, insulating barrier preferably is provided, with long-term assurance reliability and fail safe, and be desirable providing aspect the high-quality big capacity power source.

For insulating barrier,, just enough as long as it has the sealability of insulating properties, the loss of opposing solid electrolyte, air impermeability (tightness) and the thermal endurance under battery operated temperature that opposing moisture is come in from external penetration.From the viewpoint of corrosion-resistant, chemical-resistant, film forming and economic effect, can use epoxy resin, rubber, polyethylene, polypropylene, polyimides etc., preferred epoxy.

(positive end plate and negative end plate)

Can use positive end plate and negative end plate when needing.For example, for bipolar type, can from outmost collector body, directly take out electrode terminal, in this case, needn't use positive end plate and negative end plate (see figure 4).

Under the situation of using positive end plate and negative end plate, positive end plate and negative end plate should comprise the function of terminal, and from reducing the viewpoint of cell thickness, should reduce thickness as much as possible again.Yet, because the mechanical strength of the electrode, electrolyte and the collector body that pile up is little, so preferably make the intensity that end plate has is enough to clamp and support in its both sides these parts.And because suppress the internal resistance of end, the thickness of usually preferred positive end plate and negative end plate is about 0.1～2mm.

For positive end plate and negative end plate, can use the alloy of aluminium, copper, titanium, nickel, stainless steel (SUS), these metals etc.Because corrosion resistance, be easy to manufacturing, economic effect etc., aluminium is preferred.

Positive end plate and negative end plate can be used identical or different material separately.And positive end plate and negative end plate can be made of the different materials that is stacked into sandwich construction.

(positive wire and negative wire)

For metal used in positive wire and the negative wire, can use the metal that is selected from copper and iron, can use equally such as aluminium and stainless steel metals such as (SUS) and the alloy material that comprises these metals.Because suppress the increase of whole lead resistances, copper is preferred.And, in order to improve adhesive force, on each lead-in wire, can form face coat to the polymeric material of battery sheath.For this face coat, nickel is the most suitable, but also can use such as silver (Ag) and gold metal materials such as (Au).In addition, but the part of preferably exposing from battery sheath is covered with stable on heating insulation heat-shrinkable tube, so that do not contact or be routed at around the battery with equipment and cause effect of leakage electronic equipment etc.

(battery sheath (battery case))

In lithium ion battery, be not limited to bipolar type, external impact and environmental degradation in preventing to use preferably are contained in the electrical power generating device in battery sheath or the battery case.In order to reduce weight, preferably use the compound stacked film of polymer-metal etc., its part or all of periphery is engaged with each other by heat-sealing, to hold and sealed electrical power generating device.Every kind of compound stacked film of polymer-metal comprises that its both sides scribble metal such as aluminium, stainless steel, nickel and the copper of insulator (as polypropylene screen).In this case, aforesaid positive pole and negative wire should so make up, and clamp and be exposed to the outside of battery sheath with the part that makes it to be heat-sealed.The preferred good compound stacked film of polymer-metal of thermal conductance that uses because heat can be effectively from the thermal source transmission of vehicle, and the inside of battery can promptly be heated to working temperature preferably.For the compound stacked film of polymer-metal, the film that can use metal film to be arranged between the polymer film and these films are integrated into one.Its concrete example is the film that comprises the shell sheath (outermost layer of lamination), metallic diaphragm and the hot sealing layer (innermost layer of lamination) that are made of polymer film, and it is arranged in this mode and laminated one-tenth integral body.Clearly, the compound stacked film of this polymer-metal obtains like this, at first forms thermal endurance insulating resin film as polymer film in each side of metal film, and stack the heat-sealing dielectric film on the thermal endurance insulating resin film of at least one side.By heating with suitable method, make stacked film fusing and bonding in heat-sealing dielectric film part.The example of metal film is an aluminium film etc.The example of insulating resin film is PETG (thermal endurance dielectric film), nylon membrane (thermal endurance dielectric film), polyethylene film (hot melt dielectric film), polypropylene screen (hot melt dielectric film) etc.Case member of the present invention is not limited to these.Utilize this class stacked film, can be easily and steadily by methods such as ultrasonic wave joints, utilize the hot melt dielectric film, carry out the joint of the tablet of a pair of stacked film or stacked film by heat-sealing.For the reliability that makes battery maximizes for a long time, can directly engage as the metal film of the part of stacked tablet.In order to remove or stave the hot-melt resin between the metal film, metal film is engaged with each other, can use the ultrasonic wave bonding method.

Lithium rechargeable battery of the present invention can be used as the high-capacity power supply of battery car (EV), hybrid-electric car (HEV), fuel cell car, mixed fuel battery automobile etc.In other words, lithium rechargeable battery of the present invention is applicable to vehicle drive power that needs high-energy-density and high output density or accessory power supply.In this case, preferably connect a plurality of lithium ion batteries of the present invention and form battery pack.In other words, in the present invention, a plurality of lithium rechargeable batteries can be in parallel or be connected into battery pack.Therefore, by combination foundation battery (base battery), can reach in various types of vehicles requirement to capacity and voltage.Therefore, energy and the output that needs in can easily selecting to design.This has eliminated to the vehicle design of each type and has produced the needs of different batteries, feasiblely can produce base batteries in batches and reduces cost by batch process.Hereinafter, utilize accompanying drawing that the typical embodiments of battery pack is described simply.

Fig. 5 A to 5C show the battery that comprises 20 parallel connections battery pack (42V, 1Ah), each battery have two series connection bipolar cell of the present invention (24V, 50mAh).In part in parallel, lead-in wire is connected on bus made of copper (bus-bar) 56 and 58, and in the series connection part, lead-in wire 48 and 49 is connected with each other by Vibration Welding.The end of each series connection part is connected to terminal 62 and 64, forms positive terminal and negative terminal.In each side of each battery, expose the detection tabs 60 of the voltage that detects bipolar cell 41 each layers, its detection line 53 extend out to the front portion of battery pack 51.In order to form the battery pack 51 shown in Fig. 5 A to 5C,, and,, further connect with other 5 bipolar cells 41 by bus 56 parallel connections with the bipolar cell 41 of 5 parallel connections by interconnecting contact conductor with bus 56 5 bipolar cells 41 in parallel.Its four layers are piled up,, be contained in the battery housing then by bus 58 parallel connections.In this mode, connect the bipolar cell 41 of any number of packages, can accomplished required electric current, the battery pack 51 of voltage and capacity.In battery pack 51, positive terminal 62 and negative terminal 64 are formed at the front portion of battery housing 55 sides, after connecting each battery, utilize terminal lead 59 that bus 56 and positive terminal 62 and negative terminal 64 are connected to each other.In battery pack 51, detection terminal 54 is provided at the side of battery housing 55, with monitoring cell voltage (voltage of each element cell and bipolar cell).All detection tabs 60 of bipolar cell 41 all are connected on the detection terminal 54 by detection line 53.In the bottom of battery housing 55, elastomer 52 is housed.Be stacked under the situation of combined assembled battery in a plurality of battery pack 51, elastomer 52 can keep the distance between the battery pack 51, to improve absorption of vibrations, resistance to impact, insulating properties and thermal radiation.

Except aforesaid detection terminal 54, this battery pack 51 can also be installed various types of measurement mechanisms or controller according to using.And, for the lead-in wire 48 of the bipolar cell 41 that is connected to each other and 49 or joint detection joint 60 and detection line 53, can use ultrasonic bonding, thermal weld, laser welding or electron beam welding, perhaps adopt riveted joint or riveted seam (caulking).In addition, for connection bus 56 and 58 to terminal lead 59 etc., can adopt ultrasonic bonding, thermal weld, laser welding or electron beam welding.

For elastomer 52, can use resin such as rubber, spring etc.

Battery pack of the present invention can comprise bipolar cell of the present invention and battery group (battery group) in parallel with it.This battery group comprises positive pole identical with bipolar cell and negative material, has the voltage identical with bipolar cell, and is to form by the non-bipolar cell of series connection with the element cell as much of bipolar cell.In other words, for the battery that forms battery pack, can mix and use bipolar cell of the present invention and non-bipolar cell.This allows the bipolar cell of output consciousness and the non-bipolar cell of energy consciousness to be combined to form battery pack and to cancel out each other its weakness.Thereby, can reduce the weight and the size of battery pack.The ratio of using with of bipolar cell and non-bipolar cell can be determined according to battery pack required security performance and output performance.

Fig. 6 A to Fig. 6 C show bipolar cell 41 (42V, 50mAh) and battery group (42V) parallel battery, wherein battery group comprise ten series connection non-bipolar cell 31 (4.2V, 1Ah).The battery group of non-bipolar cell 31 has identical voltage with bipolar cell 41, so that form connected mode in parallel with this state.This battery pack 51A has bipolar cell 41 responsible outputs but not the battery group 31 of bipolar cell 31 is responsible for the structure of energy.This is the effective means that is used to be difficult to realize simultaneously the battery pack of required output and energy.In this battery pack 51A, copper busbar 56 is used for the part of the connection layout part in parallel battery 31 adjacent with being connected along continuous straight runs equally.Vertically adjacent battery 31 is connected with 40 by Vibration Welding lead-in wire 39 among the figure.The end of the non-bipolar cell 31 and the part of bipolar cell 41 of being connected in parallel links to each other with 64 with terminal 62, forms positive terminal and negative terminal.This battery pack 51A is identical with battery pack 51 among Fig. 5 A to Fig. 5 C, and the detection tabs 60 that just detects bipolar cell 41 each layer voltage is exposed to the both sides of battery 41, and its detection line extend out to the front portion of battery pack 51A.In order to form the battery pack 51A shown in Fig. 6 A to Fig. 6 C, with ten non-bipolar cells 31 from the end that will connect with series system and bus 56 Vibration Welding.And, battery 41 is connected with bus 56 with parallel way at two ends with series connected battery 31, in the battery housing 55 of packing into then.Connect bipolar cell 41 in this mode, making to provide the battery pack 51A that can realize required electric current, voltage and capacity.In battery pack 51A, positive terminal 62 and negative terminal 64 are formed at the front portion of the side of battery housing 55 equally, and bus 56 and positive terminal 62 and negative terminal 64 interconnect by terminal lead 59.In battery pack 51A, detection terminal 54 is equipped with in the side of battery housing 55, with monitoring cell voltage (voltage of each element cell of bipolar cell 41, bipolar cell 41 and non-bipolar cell 31).All detection tabs 60 of bipolar cell 41 all are connected to detection terminal 54 by detection line 53.In the bottom of battery housing 55, with elastomer 52.When a plurality of battery pack 51A piled up the formation combined assembled battery, elastomer 52 can keep the distance between the battery pack 51A, to improve absorption of vibrations, impact resistance, insulating properties and thermal radiation.

In addition, battery pack of the present invention can have following array structure.Aforesaid bipolar cell is connected with mode in parallel with series connection, forms first battery assembly module (assembled battery unit), connect secondary cell, form voltage second battery assembly module identical with first battery assembly module as non-bipolar cell.With first and second battery assembly modules and be unified into battery pack.

Next, when at least two aforesaid battery pack are connected with mode of mixing in parallel with series, parallel or series connection, can reach the battery capacity of various desired use and the requirement of output by lower cost, need not to prepare new battery pack.In other words, in combined assembled battery of the present invention, at first make the base batteries group, and these are formed battery pack, make to prepare battery as required.This eliminated need a lot of types of preparation have a different specification of battery group, and can reduce manufacturing cost.

Fig. 7 A to Fig. 7 C show wherein six battery pack that adopt bipolar cell shown in Fig. 5 A to Fig. 5 C (42V, 1Ah) Bing Lian combined assembled battery (42V, 6Ah).The battery pack that constitutes combined assembled battery is combined into integral body by connecting plate and fixed screw, and between battery pack elastomer is housed, to form vibration-absorption structure.The terminal of battery pack links to each other with plate-shaped bus-bars.In other words, as shown in Fig. 7 A to Fig. 7 C, for aforesaid battery pack 51 is connected into combined assembled battery 70, positive terminal 62 usefulness comprise that the positive terminal fish plate 72 of outside positive terminal part is electrically connected to each other, and negative terminal 64 usefulness comprise that the negative terminal fish plate 74 of outside negative terminal part is electrically connected to each other.On two sides of each battery housing 55, connecting plate 76 usefulness fixed screws 77 are fixing, thereby connect battery pack 51.The positive terminal 62 of each battery pack 51 and negative terminal 64 are protected with anodal and negative pole insulating cover respectively, and distinguish by the color coding with appropriate color (as red and blue).In addition, exterior elastomer 52 is arranged on the bottom of battery housing 55, to form vibration-absorption structure.

In aforesaid combined assembled battery, each battery pack that preferably constitutes in a plurality of battery pack of combined assembled battery removably connects.This is because even when part battery or battery pack break down, the part that this combined assembled battery also can only break down by replacement is repaired.

Vehicle of the present invention is characterised in that aforesaid battery pack and/or combined assembled battery is installed on it.Battery becomes in light weight, volume is little by making, and can keep big space in vehicle.And the miniaturization of battery makes the weight saving of vehicle.

As shown in Figure 8, in order to be installed on the vehicle 80, combined assembled battery 70 is installed under the seat at car body middle part.This is that following time can be designed bigger interior space and storage room because battery 70 is installed in the seat.The space that battery is installed is not limited under the seat, and can be following, the back of backrest of vehicle floor, the bottom of afterbody storage room or the engine chamber of front part of vehicle.

In the present invention, according to purposes, not only described combined assembled battery can be installed on the vehicle, and described battery pack can be installed, and the combination of described combined assembled battery and described battery pack can be installed.In addition, it is battery car, hybrid-electric car, fuel cell car, mixed fuel battery automobile etc. as the preferred vehicle of driving power, accessory power supply etc. that battery pack of the present invention and/or combined assembled battery can be installed on it, but is not limited to these.

Hereinafter, will content of the present invention be described by embodiment and Comparative Examples, but the present invention is not limited to these embodiment.

(embodiment 1-42,85,86 and Comparative Examples 1 and 2)

1. Zheng Ji preparation

At first, shown in table 1 and 2, prepare each self-contained 500nm thick, deposit and cover Li-Ni oxide (average grain diameter: 8 μ m) material of lip-deep Li compound (embodiment 1-42,85 and 86) and Li-Ni oxide (Comparative Examples 1-2 does not deposit the Li compound).By adding the N-N-methyl-2-2-pyrrolidone N-as solvent, the Li-Ni oxide, 10% quality that stir 75% quality make slurry as the acetylene black of electric conducting material, the polyvinylidene fluoride of 15% quality.With this slurry with applicator cover aluminium foil as positive electrode collector (thickness: 20 μ m), and in about 80 ℃ vacuum desiccator heat drying.Next, stamp out the electrode of diameter 15mm, under 90 ℃ and high vacuum dry 6 hours then by described aluminium foil.The thickness of the positive electrode active material layer that stamps out is 50 μ m.As for the method that covers the Li-Ni oxide with the Li compound,, cover the Li-Ni oxide with the Li compound and cover, so that have the cladding thickness of 500nm by mechanical fusion method.

2. the preparation of negative pole

By adding N-N-methyl-2-2-pyrrolidone N-as solvent, stir 85% quality as the carbon of the carbon-based material of negative electrode active material powder, 8% quality as acetylene black, 2% quality gas-phase growth of carbon fibre (VGCF) and 5% quality of electric conducting material as the polyvinylidene fluoride of binding agent, make slurry.With this slurry with applicator be applied in Copper Foil as negative electrode collector (thickness: 20 μ m), and in about 80 ℃ vacuum desiccator heat drying.Next, stamp out the electrode of diameter 16mm, under 90 ℃ and high vacuum dry 6 hours then by described Copper Foil.The thickness of the negative pole that stamps out (negative electrode active material layer) is 80 μ m.

3. the preparation of battery and evaluation

Utilize described positive pole (embodiment 1-42,85,86 and Comparative Examples 1-2) and described negative pole, form each coin cell.In the assembling of coin cell, adopt the basic microporosity separator of polypropylene (PP) (average diameter of micropore: 800nm, porosity: thickness 35%:, and adopt 1.0M LiPF 30 μ tm) as dividing plate ₆EC+DEC solution as nonaqueous electrolytic solution.In the balance of the capacity of anodal and negative pole, positive pole is dominant.

Make after the battery, in positive pole transforms, battery is charged to 4.1V with 0.2C immediately.Then battery is at room temperature kept a week., with direct current calculate internal resistance, and battery was further kept one month down 4.1V and 60 ℃ thereafter.After this, it is such to be similar to initial calculation, utilizes direct current to calculate internal resistance.Measure the expansion of coin cell simultaneously.Gained the results are shown in table 1 and 2.

Internal resistance increment rate by battery is calculated internal resistance, and by the expansion rate of battery the expansion of battery is calculated.Internal resistance increment rate (%) is based on the Li-Ni oxide that does not cover the Li compound and has just prepared internal resistance afterwards, the increase ratio of the internal resistance of each battery after 60 ℃ keep one month down.The expansion rate of battery (%) is that the size that will have the battery of 100%SOC after just preparing is set at 100% o'clock, the increase ratio of the size of each battery after 60 ℃ keep one month down.SOC (charged state) is a value of representing the ratio of the capacity that charged and battery rated capacity (rated capacity).

(embodiment 43-84,87,88 and Comparative Examples 3 and 4)

At first, as shown in Tables 3 and 4, (average grain diameter: 8 μ m) on the surface, making its volume is the material (embodiment 43-84,87 and 88) of the Li compound of 1 volume with respect to the Li-Ni oxide of 100 volumes at the Li-Ni oxide to spray to prepare each self-contained deposition.And, preparation Li-Ni oxide (average grain diameter: 8 μ m) (Comparative Examples 3 and 4 does not deposit the Li compound).In addition, prepare by the mode identical and estimate anodal and negative pole and battery with embodiment.Gained the results are shown in table 3 and 4.

Table 1

	The type of used LiNi complex oxide in the positive active material	The Li compound of deposition	The thickness (nm) of the Li compound of deposition	The expansion rate of battery (%)	The internal resistance increment rate (%) of battery
						Embodiment 1	LiNi 0.83Co 0.15Al 0.02O 2	Lithium phosphate	500	3	1.5
Embodiment 2	LiNi 0.83Co 0.15Al 0.02O 2	Li 2.9PO 3.3N 0.36	500	2	1.6
						Embodiment 3	LiNi 0.83Co 0.15Al 0.02O 2	Li 2O-B 2O 3	500	2	1.4
Embodiment 4	LiNi 0.83Co 0.15Al 0.02O 2	Li 2O-B 2O 3-Lil	500	3	1.5
						Embodiment 5	LiNi 0.83Co 0.15Al 0.02O 2	Li 2S-SiS 2	500	3	1.7
Embodiment 6	LiNi 0.83Co 0.15Al 0.02O 2	Li 2S-SiS 2-Li 3PO 4	500	3	1.6
						Embodiment 7	LiNi 0.83Co 0.15Al 0.02O 2	Cobalt acid lithium	500	2	1.4
Embodiment 8	LiNi 0.83Co 0.15Al 0.02O 2	LiMn2O4	500	2	1.4
						Embodiment 9	LiNi 0.83Co 0.15Al 0.02O 2	LiFePO 4	500	3	1.7
Embodiment 10	LiNi 0.83Co 0.15Al 0.02O 2	Lithium hydroxide	500	3	1.5
						Embodiment 11	LiNi 0.83Co 0.15Al 0.02O 2	Lithium fluoride	500	3	1.6
Embodiment 12	LiNi 0.83Co 0.15Al 0.02O 2	Lithium acetate	500	2	2.3
						Embodiment 13	LiNi 0.83Co 0.15Al 0.02O 2	Ethinylation lithium-ethylenediamine	500	3	2.2
Embodiment 14	LiNi 0.83Co 0.15Al 0.02O 2	Lithium benzoate	500	1	2.4
						Embodiment 15	LiNi 0.83Co 0.15Al 0.02O 2	Lithium bromide	500	2	2.5
Embodiment 16	LiNi 0.83Co 0.15Al 0.02O 2	Lithium carbonate	500	2	2.3
						Embodiment 17	LiNi 0.83Co 0.15Al 0.02O 2	Lithium nitrate	500	1	2.2
Embodiment 18	LiNi 0.83Co 0.15Al 0.02O 2	Lithium oxalate	500	3	2.5
						Embodiment 19	LiNi 0.83Co 0.15Al 0.02O 2	The pyruvic acid lithium	500	1	2.6
Embodiment 20	LiNi 0.83Co 0.15Al 0.02O 2	Lithium stearate	500	1	2.3
						Embodiment 21	LiNi 0.83Co 0.15Al 0.02O 2	Lithium tartrate	500	1	2.3
Embodiment 85	LiNi 0.83Co 0.15Al 0.02O 2	Lithium sulfate	500	1	2.1
						Comparative Examples 1	LiNi 0.83Co 0.15Al 0.02O 2	Do not have	-	15	2.7

Table 2

	The type of used LiNi complex oxide in the positive active material	The Li compound of deposition	The thickness (nm) of the Li compound of deposition	The expansion rate of battery (%)	The internal resistance increment rate (%) of battery
						Embodiment 22	LiNi 0.5Mn 0.5O 2	Lithium phosphate	500	2	2.0
Embodiment 23	LiNi 0.5Mn 0.5O 2	Li 2.9PO 3.3N 0.36	500	2	1.8
						Embodiment 24	LiNi 0.5Mn 0.5O 2	Li 2O-B 2O 3	500	2	1.9
Embodiment 25	LiNi 0.5Mn 0.5O 2	Li 2O-B 2O 3-Lil	500	3	2.1
						Embodiment 26	LiNi 0.5Mn 0.5O 2	Li 2S-SiS 2	500	1	1.7
Embodiment 27	LiNi 0.5Mn 0.5O 2	Li 2S-SiS 2-Li 3PO 4	500	1	1.6
						Embodiment 28	LiNi 0.5Mn 0.5O 2	Cobalt acid lithium	500	1	1.9
Embodiment 29	LiNi 0.5Mn 0.5O 2	LiMn2O4	500	2	2.0
						Embodiment 30	LiNi 0.5Mn 0.5O 2	LiFePO 4	500	3	2.1
Embodiment 31	LiNi 0.5Mn 0.5O 2	Lithium hydroxide	500	1	1.8
						Embodiment 32	LiNi 0.5Mn 0.5O 2	Lithium fluoride	500	1	1.9
Embodiment 33	LiNi 0.5Mn 0.5O 2	Lithium acetate	500	2	3.0
						Embodiment 34	LiNi 0.5Mn 0.5O 2	Ethinylation lithium-ethylenediamine	500	3	2.9
Embodiment 35	Li Ni 0.5Mn 0.5O 2	Lithium benzoate	500	1	3.1
						Embodiment 36	LiNi 0.5Mn 0.5O 2	Lithium bromide	500	1	3.1
Embodiment 37	LiNi 0.5Mn 0.5O 2	Lithium carbonate	500	2	3.0
						Embodiment 38	LiNi 0.5Mn 0.5O 2	Lithium nitrate	500	2	3.2
Embodiment 39	LiNi 0.5Mn 0.5O 2	Lithium oxalate	500	3	3.1
						Embodiment 40	LiNi 0.5Mn 0.5O 2	The pyruvic acid lithium	500	3	2.9
Embodiment 41	LiNi 0.5Mn 0.5O 2	Lithium stearate	500	3	2.5
						Embodiment 42	LiNi 0.5Mn 0.5O 2	Lithium tartrate	500	3	2.9
Embodiment 86	LiNi 0.5Mn 0.5O 2	Lithium sulfate	500	2	2.3
						Comparative Examples 2	LiNi 0.5Mn 0.5O 2	Do not have	-	10	3.5

Table 3

	The type of used LiNi complex oxide in the positive active material	The Li compound of deposition	The thickness (nm) of the Li compound of deposition	The expansion rate of battery (%)	The internal resistance increment rate (%) of battery
						Embodiment 43	LiNi 0.83Co 0.15Al 0.02O 2	Lithium phosphate	1	5	1.3
Embodiment 44	LiNi 0.83Co 0.15Al 0.02O 2	Li 2.9PO 3.3N 0.36	1	6	1.4
						Embodiment 45	LiNi 0.83Co 0.15Al 0.02O 2	Li 2O-B 2O 3	1	5	1.3
Embodiment 46	LiNi 0.83Co 0.15Al 0.02O 2	Li 2O-B 2O 3-Lil	1	6	1.5
						Embodiment 47	LiNi 0.83Co 0.15Al 0.0O 2	Li 2S-SiS 2	1	5	1.6
Embodiment 48	LiNi 0.83Co 0.15Al 0.02O 2	Li 2S-SiS 2-Li 3PO 4	1	5	1.4
						Embodiment 49	LiNi 0.83Co 0.15Al 0.02O 2	Cobalt acid lithium	1	5	1.5
Embodiment 50	LiNi 0.83Co 0.15Al 0.02O 2	LiMn2O4	1	6	1.3
						Embodiment 51	LiNi 0.83Co 0.15Al 0.02O 2	LiFePO 4	1	4	1.4
Embodiment 52	LiNi 0.83Co 0.15Al 0.02O 2	Lithium hydroxide	1	4	1.2
						Embodiment 53	LiNi 0.83Co 0.15Al 0.02O 2	Lithium fluoride	1	5	1.6
Embodiment 54	LiNi 0.83Co 0.15Al 0.02O 2	Lithium acetate	1	4	1.4
						Embodiment 55	LiNi 0.83Co 0.15Al 0.02O 2	Ethinylation lithium-ethylenediamine	1	4	2.3
Embodiment 56	LiNi 0.83Co 0.15Al 0.02O 2	Lithium benzoate	1	5	2.4
						Embodiment 57	LiNi 0.83Co 0.15Al 0.02O 2	Lithium bromide	1	6	2.2
Embodiment 58	LiNi 0.83Co 0.15Al 0.02O 2	Lithium carbonate	1	4	2.6
						Embodiment 59	LiNi 0.83Co 0.15Al 0.02O 2	Lithium nitrate	1	4	2.5
Embodiment 60	LiNi 0.83Co 0.15Al 0.02O 2	Lithium oxalate	1	4	2.2
						Embodiment 61	LiNi 0.83Co 0.15Al 0.02O 2	The pyruvic acid lithium	1	6	2.3
Embodiment 62	LiNi 0.83Co 0.15Al 0.02O 2	Lithium stearate	1	6	2.4
						Embodiment 63	LiNi 0.83Co 0.15Al 0.02O 2	Lithium tartrate	1	5	2.3
Embodiment 87	LiNi 0.83Co 0.15Al 0.02O 2	Lithium sulfate	1	5	2.1
						Comparative Examples 3	LiNi 0.83Co 0.15Al 0.02O 2	Do not have	-	17	2.7

Table 4

	The type of used LiNi complex oxide in the positive active material	The Li compound of deposition	The thickness (nm) of the Li compound of deposition	The expansion rate of battery (%)	The internal resistance increment rate (%) of battery
						Embodiment 64	LiNi 0.5Mn 0.5O 2	Lithium phosphate	1	6	1.4
Embodiment 65	LiNi 0.5Mn 0.5O 2	Li 2.9O 3.3N 0.36	1	4	1.2
						Embodiment 66	LiNi 0.5Mn 0.5O 2	Li 2O-B 2O 3	1	4	1.3
Embodiment 67	LiNi 0.5Mn 0.5O 2	Li 2O-B 2O 3-Lil	1	4	1.4
						Embodiment 68	LiNi 0.5Mn 0.5O 2	Li 2S-SiS 2	1	6	1.3
Embodiment 69	LiNi 0.5Mn 0.5O 2	Li 2S-SiS 2-Li 3PO 4	1	6	1.2
						Embodiment 70	LiNi 0.5Mn 0.5O 2	Cobalt acid lithium	1	5	1.3
Embodiment 71	LiNi 0.5Mn 0.5O 2	LiMn2O4	1	4	1.4
						Embodiment 72	LiNi 0.5Mn 0.5O 2	LiFePO 4	1	4	1.2
Embodiment 73	LiNi 0.5Mn 0.5O 2	Lithium hydroxide	1	4	1.5
						Embodiment 74	LiNi 0.5Mn 0.5O 2	Lithium fluoride	1	6	1.2
Embodiment 75	LiNi 0.5Mn 0.5O 2	Lithium acetate	1	4	2.3
						Embodiment 76	LiNi 0.5Mn 0.5O 2	Ethinylation lithium-ethylenediamine	1	5	2.4
Embodiment 77	LiNi 0.5Mn 0.5O 2	Lithium benzoate	1	4	2.3
						Embodiment 78	LiNi 0.5Mn 0.5O 2	Lithium bromide	1	6	2.2
Embodiment 79	LiNi 0.5Mn 0.5O 2	Lithium carbonate	1	5	2.5
						Embodiment 80	LiNi 0.5Mn 0.5O 2	Lithium nitrate	1	6	2.3
Embodiment 81	LiNi 0.5Mn 0.5O 2	Lithium oxalate	1	5	2.5
						Embodiment 82	LiNi 0.5Mn 0.5O 2	The pyruvic acid lithium	1	5	2.3
Embodiment 83	LiNi 0.5Mn 0.5O 2	Lithium stearate	1	5	2.5
						Embodiment 84	LiNi 0.5Mn 0.5O 2	Lithium tartrate	1	6	2.3
Embodiment 88	LiNi 0.5Mn 0.5O 2	Lithium sulfate	1	6	2.2
						Comparative Examples 4	LiNi 0.5Mn 0.5O 2	Do not have	-	10	3.5

Result from table 1 to table 4 can confirm, each Comparative Examples that is not deposited on the Li-Ni oxide surface with Li compound is wherein compared, comprising that wherein the Li compound is deposited among any embodiment of material as positive electrode of Li-Li oxide surface, can suppress the expansion of battery more.And, with regard to battery performance, can confirm that the internal resistance increment rate after preserving can be controlled to be the internal resistance increment rate after the preservation that is equal to or less than Comparative Examples.This announcement has the battery of high voltage (being in charged state), being in about 60 ℃ high temperature (60 ℃ or higher) environment, in vehicle, especially is installed in engine chamber or during near motor, its charging and discharge operational excellence.In other words, at high temperature also can move effectively, not exist reaction to carry out naturally and produce the problem that gas or internal resistance increase even this announcement has high-tension battery.

The applying date is the day disclosure special permission communique P2003-407542 on December 5th, 2003, and the applying date is that the full content that day disclosure on November 18th, 2004 is speciallyyed permit communique P2004-334800 all is incorporated herein by reference.

Although with reference to its some embodiment the present invention has been described above, the present invention is not limited to above-mentioned embodiment, and those skilled in the art should expect this point according to instruction.Scope of the present invention is determined according to following claims.

Industrial applicibility

According to the positive electrode for lithium ion battery with nonaqueous electrolyte of the present invention, the Li Compound deposition is on the surface as the Li-Ni oxide of positive active material, thus, even charging and discharging at high temperature still can suppress significantly the Li-Ni oxide and produce oxygen radical. Thereby the decomposition that can suppress as much as possible electrolyte also reduces the expansion of battery significantly.

Claims (8)

1. positive electrode that is used for lithium ion battery with nonaqueous electrolyte comprises:

The oxide that contains lithium and nickel; And

Be deposited on the lithium compound on this oxide surface, this lithium compound covers the nickel that exists on the described oxide surface,

Wherein when whole when surface of this lithium compound of deposition with basic this oxide of covering, the tectal thickness of this lithium compound is 5nm to 1 μ m, wherein when this lithium compound of deposition when spraying on the surface at this oxide, the volume of this lithium compound is 0.5 to 10, and the volume of supposing positive active material is 100.

2. according to the positive electrode of claim 1, wherein this lithium compound comprises lithium ion conductive.

3. according to the positive electrode of claim 1, wherein this lithium compound is to be selected from least a in following: lithium phosphate, nitrogen phosphorous oxide lithium, Li ₂O-B ₂O ₃Compound, Li ₂O-B ₂O ₃-LiI compound, Li ₂O-SiS ₂Compound, Li ₂S-SiS ₂-Li ₃PO ₄Compound, lithium and cobalt oxides, lithium manganese oxide, LiFePO ₄, and lithium hydroxide.

4. lithium ion battery with nonaqueous electrolyte comprises:

Positive electrode, this positive electrode comprises: the oxide that contains lithium and nickel; And be deposited on lithium compound on this oxide surface, this lithium compound covers the nickel that exists on this oxide surface,

Wherein when whole when surface of this lithium compound of deposition with basic this oxide of covering, the tectal thickness of this lithium compound is 5nm to 1 μ m, wherein when this lithium compound of deposition when spraying on the surface at this oxide, the volume of this lithium compound is 0.5 to 10, and the volume of supposing positive active material is 100.

5. battery pack comprises:

Lithium ion battery with nonaqueous electrolyte, this lithium ion battery with nonaqueous electrolyte comprises positive electrode, this positive electrode comprises: the oxide that contains lithium and nickel; And be deposited on lithium compound on this oxide surface, this lithium compound covers the nickel that exists on this oxide surface, wherein when whole when surface of this lithium compound of deposition with basic this oxide of covering, the tectal thickness of this lithium compound is 5nm to 1 μ m, wherein when this lithium compound of deposition when spraying on the surface at this oxide, the volume of this lithium compound is 0.5 to 10, and the volume of supposing positive active material is 100

Wherein a plurality of described lithium ion batteries connect in the serial or parallel connection mode and install.

6. combined assembled battery comprises:

Battery pack, this battery pack comprises lithium ion battery with nonaqueous electrolyte, and this lithium ion battery with nonaqueous electrolyte comprises positive electrode, and this positive electrode comprises: the oxide that contains lithium and nickel; And be deposited on lithium compound on this oxide surface, this lithium compound covers the nickel that exists on this oxide surface, wherein when whole when surface of this lithium compound of deposition with basic this oxide of covering, the tectal thickness of this lithium compound is 5nm to 1 μ m, wherein when this lithium compound of deposition when spraying on the surface at this oxide, the volume of this lithium compound is 0.5 to 10, and the volume of supposing positive active material is 100

Wherein a plurality of described lithium ion batteries connect in the serial or parallel connection mode and install.

7. according to the combined assembled battery of claim 6, wherein said battery pack can be dismantled independently.

8. according to the combined assembled battery of claim 6, wherein this combined assembled battery is installed on the vehicle.

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