CN101015075A

CN101015075A - Negative electrode for nonaqueous secondary battery

Info

Publication number: CN101015075A
Application number: CNA2005800304082A
Authority: CN
Inventors: 松岛智善; 本田仁彦; 坂口善树; 百武正浩; 安田清隆
Original assignee: Mitsui Mining and Smelting Co Ltd
Current assignee: Mitsui Mining and Smelting Co Ltd
Priority date: 2004-09-09
Filing date: 2005-06-30
Publication date: 2007-08-08
Anticipated expiration: 2025-06-30
Also published as: CN100514716C

Abstract

Disclosed is a negative electrode (10) for nonaqueous electrolyte secondary batteries which comprises an active material layer (2) containing active material particles (2a). In the active material layer (2), a metal material (4) deposited by electrolytic plating permeates between the particles. The negative electrode (10) has many vertical holes (5) extending in the thickness direction of the active material layer (2), and these vertical holes (5) are open at least at one side. The negative electrode (10) further comprises a pair of collector layers (3a, 3b) which are in contact with the electrolyte solution, and the active material layer (2) is interposed between the collector layers (3a, 3b). The aperture ratio of the vertical holes (5) which are open at the surface of the negative electrode (10) is preferably 0.3-30%. It is also preferable that at least one of the collector layers (3a, 3b) has a thickness of 0.3-10 mum.

Description

Negative electrode for nonaqueous secondary battery

Technical field

The present invention relates to the negative pole that nonaqueous electrolytic solution secondary batteries such as lithium rechargeable battery are used.

Background technology

Existing a kind of negative electrode for lithium secondary battery open (opening flat 8-50922 communique) with reference to the spy, it has the metallic element that forms the metallic element of alloy and do not form alloy with lithium with lithium as inscape, contact with the electrolyte of negative pole and in the face of anodal surface with part that lead-out terminal is connected in the containing ratio height of the metallic element of lithium formation alloy.It is believed that, according to this negative pole, even micronizing takes place owing to discharging and recharging in the metallic element that forms alloy with lithium, also can be by not forming the metallic element maintenance conductivity of alloy with lithium.

Open in the flat 8-50922 communique above-mentioned spy, concrete structure as negative pole, also proposed: will contain that the member of powder shaped that forms the metallic element of alloy with lithium bonds to the structure that forms on the collector component of the metal that does not form alloy with adhesive and it is burnt till after the structure that obtains.And, also proposed to form configuration on the layer of metallic element of alloy does not form alloy with lithium metallic element containing with lithium.Do not form the metallic element of alloy for example by electroplating formation with lithium.

But above-mentioned spy opens the negative pole of being put down in writing in the flat 8-50922 communique can not obtain sufficient surface coverage and intensity because cover negative terminal surface to form the thickness of layer of metallic element of alloy not extremely thin with lithium, reach about 50nm.Its result is shunk the stress that caused change in volume produces and can not fully alleviate owing to discharging and recharging to expand by active material, and obvious distortion has taken place negative pole.And, owing to the contraction of expanding takes place under the micronized situation, can not prevent coming off of active material effectively at active material.Therefore, be not easy to improve the cycle characteristics of negative pole.

To open flat 8-50922 communique different with above-mentioned spy, also proposed to have the negative electrode for nonaqueous secondary battery (opening the 2001-76761 communique with reference to the spy) in the hole that connects active material layer.But the possibility that has active material to come off from the sidewall of through hole in this negative pole, takes place to be difficult to keep conductivity under the micronized situation owing to expand shrinking at active material.Therefore, be not easy to improve the cycle characteristics of negative pole.

Summary of the invention

Therefore, the purpose of this invention is to provide the negative electrode for nonaqueous secondary battery that can solve the above-mentioned various shortcoming that prior art had.

The present invention has reached above-mentioned purpose by following negative electrode for nonaqueous secondary battery is provided, this negative electrode for nonaqueous secondary battery possesses the active material layer of the particle that contains active material, in this active material layer, the metal material of separating out by plating is impregnated between the particle, and described negative pole has a large amount of vertically holes, and the perforate on the one side at least of described negative pole of this vertical hole forms and extends along the thickness direction of described active material layer.

And the present invention also provides nonaqueous electrolytic solution secondary battery, it is characterized in that, has above-mentioned negative pole.

Description of drawings

Fig. 1 is the schematic diagram of cross-section structure of the 1st execution mode of expression negative pole of the present invention.

Fig. 2 (a) to Fig. 2 (g) be the process chart of expression by an example of the manufacture method of negative pole shown in Figure 1.

Fig. 3 is the schematic diagram that expression is formed with the state of current collection layer and micro cellular voids.

Fig. 4 is the schematic diagram of cross-section structure of the 2nd execution mode of expression negative pole of the present invention.

Fig. 5 (a) to Fig. 5 (h) be the process chart of expression by an example of the manufacture method of negative pole shown in Figure 4.

Fig. 6 is the schematic diagram of cross-section structure of the 3rd execution mode of expression negative pole of the present invention.

Fig. 7 is the schematic diagram of cross-section structure of the 4th execution mode of expression negative pole of the present invention.

Fig. 8 (a) to Fig. 8 (e) be the process chart of expression by an example of the manufacture method of negative pole shown in Figure 7.

Fig. 9 is the schematic diagram of cross-section structure of the 5th execution mode of expression negative pole of the present invention.

Figure 10 (a) is to show by before the use of embodiment 1 resulting negative pole and use the photo of the outward appearance after 1 circulation to Figure 10 (d).

Figure 11 (a) is to amplify the scanning electron microscope photo that shows by the surface and the vertical section of embodiment 1 resulting negative pole to Figure 11 (d).

Embodiment

Below, the present invention will be described based on its preferred implementation and with reference to accompanying drawing.At first the negative pole to as shown in Figure 1 the 1st execution mode describes.The negative pole 10 of present embodiment have as with the contacted table of electrolyte in an opposite i.e. the 1st 1a and the 2nd 1b.Negative pole 10 possesses active material layer 2.Active material layer 2 is by a pair of current collection layer 3a that forms on each face of this layer 2 respectively, and 3b covers continuously.Each current collection layer 3a, 3b contain the 1st 1a and the 2nd 1b respectively.And can find out significantly that from Fig. 1 electrode 10 does not have the thick-film conductor body that the employed current collection that is called as collector body is used in the former electrode (for example thickness is metal forming or the drawn metal about 12～35 μ m).

In the negative pole 10 of present embodiment, current collection layer 3a, 3b have born the current collection function.And the active material that current collection layer 3a, 3b are used for preventing to be contained in the active material layer 2 takes place to come off after change in volume and the micronizing owing to discharging and recharging.

The thick-film conductor body that the current collection that uses among each current collection layer 3a, 3b and former electrode is used is compared its thin thickness.Specifically, be preferably about 0.3～10 μ m, be preferably especially about 0.4～8 μ m, especially be preferably the thin layer about 0.5～5 μ m.Thus, can almost entirely and continuously cover active material layer 2 with required minimal thickness.As a result, can prevent the coming off of active material after the micronizing.And by making the thin layer of this thickness, and do not have the thick-film conductor body that current collection is used, the shared ratio of active material improves relatively in the whole negative pole, can improve the energy density of per unit volume and per unit weight.Concerning former electrode, because the shared ratio height of the thick-film conductor body that current collection is used in the entire electrode, so be limited aspect the raising energy density.Preferably, the current collection layer 3a of above-mentioned scope, 3b form by electroplating as described later.Other 2 current collection layer 3a, the thickness of 3b can be identical, perhaps also can be different.

As mentioned above, 2 current collection layer 3a, 3b contain the 1st 1a and the 2nd 1b respectively.Under the negative pole 10 with present embodiment was assembled into situation in the battery, the 1st 1a and the 2nd 1b just became and contacted of electrolyte.Relative therewith, the thick-film conductor body that the current collection in electrode is in the past used does not contact with electrolyte under the situation that is formed with active material on its two sides, even and on its one side, form under the situation of active material, also have only single face to contact with electrolyte.That is to say, negative pole 10 for present embodiment, do not have the thick-film conductor body that employed current collection is used in the former electrode, being positioned at the outmost layer of electrode is current collection layer 3a, the function that the active material after 3b has the current collection function simultaneously concurrently and prevents micronizing comes off.

Because contain each current collection layer 3a of the 1st 1a and the 2nd 1b respectively, 3b has the current collection function, so under situation about the negative pole in the present embodiment 10 being assembled in the battery, for each current collection layer 3a, 3b can both connect electric current and take out with the such advantage of lead.

Each current collection layer 3a, 3b are made of the metal that can form the collector body that obtains nonaqueous electrolytic solution secondary battery.Especially preferably the metal by the collector body that can form lithium rechargeable battery constitutes.As such metal, for example can list, lithium compound forms the low element of ability.Can enumerate the alloy of copper, nickel, iron, cobalt or these metals etc. as the low element of lithium compound formation ability.It is specially suitable using copper or nickel or their alloy in these metals.Especially, because can make current collection layer 3a when using nickel-tungsten, 3b becomes high strength, so be preferred.2 current collection layer 3a, the constituent material of 3b can be identical, perhaps also can be inequality.The meaning of " the formation ability of lithium compound is low " is meant, does not form intermetallic compound or solid solution with lithium, even perhaps formed, lithium also is a trace or very unsettled.

Be positioned at each collector body 3a, the active material layer 2 between the 3b contains the particle 2a of active material.Active material layer 2 is to apply the conductive paste (slurry) of the particle 2a that for example contains active material and form.As active material, for example can enumerate silicon based material or tin based material, aluminium based material, germanium based material.Preferred especially silicon based material.Because active material layer 2 is by 2 current collection layer 3a, 3b covers, so can prevent from effectively to cause the active material micronizing and come off owing to discharging and recharging.And, by having formed vertical hole described later, make the particle 2a of active material to contact, so also can the impeded electrode reaction with electrolyte.

The maximum particle diameter of the particle 2a of active material is preferably below the 30 μ m, more preferably below the 10 μ m.And at the particle diameter of particle with D ₅₀During value representation, then be preferably 0.1～8 μ m, be preferably 0.3～2 μ m especially.When maximum particle diameter surpasses 30 μ m, exist the coming off of particle, the situation that shortens electrode life take place easily.There is no particular limitation for the lower limit of particle diameter, more little preferred more.Consider the manufacture method of this particle, lower limit is about 0.01 μ m.The particle diameter of particle is measured by electron microscope observation (SEM observation) by laser diffraction and scattering formula particle size distribution.

Active material is difficult to fully improve the energy density of battery with respect to the amount of whole negative pole very little the time, and when too many, the incidental tendency of coming off of active material is arranged.If consider these aspects, then active material is preferably 5～80 weight % with respect to the amount of whole negative pole, and more preferably 10～50 weight % most preferably are 20～50 weight %.

The thickness of active material layer 2 with respect to the particle diameter of the ratio of the amount of whole negative pole and active material and can suitably regulate, does not have special critical value according to active material in the present embodiment.Be generally 1～100 μ m, particularly about 3～60 μ m.As hereinafter described, active material layer preferably forms by the conductive paste that coating contains active material particle.

In active material layer 2, as shown in Figure 1, soaking into lithium compound between the particle that in this layer, is contained and forming the low metal material 4 of ability.Metal material 4 is separated out between particle by plating.Metal material 4 preferably is impregnated into the whole thickness direction of active material layer 2.The particle 2a that has active material in preferred then this material after soaking into.That is, preferred active material particle 2a is exposed on the surface of negative pole 10, but is embedded in each collector body 3a, the inside of 3b.Thus, make active material layer 2 and current collection layer 3a, the adaptation of 3b strengthens, and has further prevented coming off of active material.And because guaranteed current collection layer 3a by the above-mentioned material 4 after being impregnated in the active material 2, electronic conductivity between 3b and the active material, so prevented to generate the isolated active material of electricity effectively, particularly generate the isolated active material of electricity, guaranteed the current collection function in the deep of active material layer 2.As a result, the function that has suppressed negative pole reduces, and has also realized the long lifetime of negative pole.The material that is semiconductor in use, but lacks electronic conductivity for example use the silicon based material as active material situation under, this is particularly advantageous.

The low metal material 4 of lithium compound formation ability that is impregnated in the active material layer 2 is the materials with conductivity, as an example, can enumerate the metal materials such as alloy of copper, nickel, iron, cobalt or these metals.This material can with constitute current collection layer 3a, the material of 3b is a same material, also can be same material not.

The low metal material 4 of lithium compound formation ability that is impregnated in the active material layer 2 preferably runs through active material layer 2 along thickness direction.Thus, 2 current collection layer 3a, 3b is conducted by metal material 4, and the electronic conductivity of whole negative pole further improves.The whole negative pole 10 that is present embodiment is made the as a whole current collection function that has.Lithium compound forms the whole thickness direction that the low metal material 4 of ability soaks into active material layer 2, can be by being that the electron microscope mapping (mapping) of determination object is confirmed with this material.The method for optimizing that is used for making the low metal material 4 of lithium compound formation ability be impregnated into active material layer 2 is described in the back.

Preferably, be not to be formed the low metal material 4 of ability by lithium compound to be full of fully, but between this particle, have the space between the active particle 2a in active material layer 2.Because the existence in this space has been alleviated active particle 2a and owing to discharging and recharging the caused stress of change in volume has been taken place.From this viewpoint, the space ratio in active material layer 2 is preferably about 0.1～30 volume %, particularly about 0.5～5 volume %.The ratio in space can be surveyed and drawn (mapping) and be tried to achieve by electron microscope.Because active material layer 2 is to contain the conductive paste of active material 2a and make it dry by coating to form, so naturally and understandably formed the space in active material layer 2.Therefore, for the space being set in the ratio of above-mentioned scope, suitably select the particle diameter of active material particle 2a for example, the composition of conductive paste, the coating condition of slurry to get final product.Also can coating coating slurry and dry with after forming active material layer 2, carry out press process under suitable condition and adjust the ratio in space.In addition, it should be noted that said space does not comprise vertical hole 5 described later here.

In active material layer, except the particle 2a that contains active material, also can contain conductive carbon material.Anticathode 10 has further been given electronic conductivity thus.The amount of the conductive carbon material that is contained active material layer from this viewpoint is preferably 0.1～20 weight %, especially preferably 1～10 weight %.Use for example particle of acetylene carbon black, graphite etc. as conductive carbon material.From further giving the electronic conductivity this respect, the particle diameter of these particles is preferably below the 40 μ m, is preferably especially below the 20 μ m.Lower limit for this particle has no particular limits, and is more little preferred more.In view of the manufacture method of this particle, then its lower limit is about 0.01 μ m.

As shown in Figure 1, negative pole 10 has in the surperficial perforate formation of negative pole 10 and along active material layer 2 and each current collection layer 3a, a large amount of vertically holes 5 that the thickness direction of 3b extends.Vertically hole 5 is the thickness directions that connect negative pole 10.In active material layer 2, active material layer 2 is exposed to the wall in vertical hole 5.Vertically the effect in hole 5 roughly can list to following several.

The first, the effect that the active material 2 that exposes by the wall in vertical hole 5 arrives electrolyte supply active material layer inside.In this case, though active material 2 exposes on the wall in vertical hole 5, because soaked into metal material 4 between the particle 2a of the active material in active material layer, so prevented coming off of this particle 2a.

It two is that the active material particle 2a in active material layer is alleviated the effect by the caused stress of change in volume owing to discharging and recharging under the situation that change in volume takes place.Alleviation by the caused stress of change in volume mainly is to take place on the in-plane of negative pole 10.That is, that part of vertical hole 5 absorptions that become the space that the volume of the particle 2a of the active material of volume increases have been increased owing to charging.As a result, prevented the obvious distortion of negative pole 10 effectively.

Other effects as vertical hole 5 have the effect that the gas that produces in the negative pole can be released to its outside.In detail, because the moisture that trace contains in negative pole has produced H ₂, CO, CO ₂Deng gas.When these gases were put aside in negative pole, polarization increased, and becomes the reason that discharges and recharges loss.Owing to formed vertical hole 5, by it above-mentioned gas is released to the negative pole outside, so can reduce by the polarization that this gas causes.Also have,, the exothermic effects of negative pole is arranged as other the effect in vertical hole 5.In detail, owing to formed vertical hole 5, the specific area of negative pole increases, so follow the heat that embedding produced of Li to be put into the outside of negative pole effectively.And,, cause heating sometimes thus when the change in volume owing to the particle 2a of active material produces when causing stress.Owing to formed vertical hole 5, this stress is eased, so the generation of heat itself just has been suppressed.

The viewpoint of the stress that causes by the change in volume of the particle 2a of active material from viewpoint that electrolyte fully is provided in active material layer with from effective alleviation, percent opening in vertical hole 5 that the surperficial perforate of negative pole 10 forms, promptly multiply by 100 value divided by the vertical summation of the area in hole 5 and be preferably 0.3～30%, be preferably 2～15% especially with the outward appearance area of negative pole 10.According to identical reason, the perforate in vertical hole 5 that the surperficial perforate of negative pole 10 forms directly is preferably 5～500 μ m, is preferably 20～100 μ m especially.And, be preferably set to 20～600 μ m by spacing (pitch) with vertical hole 5, more preferably be set at 45～400 μ m, thereby can supply with electrolyte fully in active material layer, and can alleviate effectively by the change in volume of the particle 2a of active material and the stress that causes.Also have, when being conceived to the lip-deep arbitrary portion of negative pole 10, to averaging in the foursquare field of view of 1cm * 1cm, vertical hole 5 that perforate forms is preferably 100～250000, be preferably 1000～40000 especially, especially be preferably 5000～20000.

In the negative pole 10 of present embodiment, vertically hole 5 connects the thickness direction of negative pole 10.But, if consider the effect in the vertical hole 5 that electrolyte is supplied in the active material layer fully and alleviate the stress that the change in volume owing to the particle 2a of active material causes, then vertically hole 5 needs not to be the thickness direction that connects negative pole 10, so long as form and to arrive active material layer 2 at least just passable in the surperficial perforate of negative pole 10.

In negative pole 10 as shown in Figure 1 preferably, at each collector body 3a, 3b perforate on as the 1st 1a on its surface and the 2nd 1b forms and has a large amount of fine voids 6 (it should be noted that fine voids 6 is different with the space of formation in the active material layer 2) that connect with active material layer.Fine voids 6 is with along each current collection layer 3a, and the mode that the thickness direction of 3b extends is present in this current collection layer 3a, among the 3b.Electrolyte can circulate in fine voids 6.Fine voids 6 is compared with vertical hole 5 of top explanation has finer structure.The effect of fine voids 6 has been auxiliary effects that electrolyte supplied to fully the vertical hole 5 in the active material layer.Therefore, fine voids 6 is not necessary structure in the present invention.

With current collection layer 3a, 3b carries out under the situation that section observes, and fine voids 6 is that width is approximately the fine structure about 0.1 μ m to 10 μ m.Though be fine, fine voids 6 has the width that can soak into electrolyte.Especially specific surface tension is little mutually with aqueous electrolyte because of nonaqueous electrolytic solution, so also can soak into fully even the width of fine voids 6 is little.Fine voids 6 preferably electroplating formation current collection layer 3a, forms during 3b simultaneously.

When by electron microscope observation the 1st 1a and the 2nd 1b being carried out viewed in plan, the average perforated area of the fine voids 6 at least one face is 0.1～50 μ m ²Be preferably 0.1～20 μ m ², 0.5～10 μ m more preferably ²About.By being set at the perforated area of this scope, can guarantee fully soaking into of electrolyte, and can effectively prevent coming off of active material.And, begin just can improve charge/discharge capacity from the initial stage that discharges and recharges.

When the face that average perforated area in the 1st 1a and the 2nd 1b is satisfied above-mentioned scope by electron microscope observation carries out viewed in plan, the ratio of the summation of the perforated area of fine voids 6 and the area of field of view (this ratio is called as percent opening) is preferably 0.1～20%, and more preferably 0.5～10%.This reason is identical with the reason that perforated area with fine voids 6 is decided to be above-mentioned scope.In addition, also because identical reason, when the face that satisfies above-mentioned scope by average perforated area among the 1st 1a of electron microscope observation and the 2nd 1b carries out viewed in plan, no matter adopt what kind of field of view, 100 μ m * 100 μ m preferably have within sweep of the eye 1～20,000, especially preferably have 10～1,000, especially preferably have 30～500 fine voids 6 and have (this value is called distributive law).

Next with reference to Fig. 2 the preferred fabrication method of the negative pole 10 of present embodiment is described.In this manufacture method, form current collection layer 3b, then form active material layer 2 thereon, and then form current collection layer 3a by electroplating in the above, form the operation in vertical hole 5 at last by electroplating.At first, shown in Fig. 2 (a), prepare foils 11.Foils 11 is the supports that are used for being used to make negative pole 10.And, be used to perhaps in the process of battery assembling processing, support negative pole before the use of the negative pole of being made 10, the usability of negative pole 10 is improved.From these viewpoints, preferably, foils 11 has in the manufacturing process of negative pole 10 and the intensity that does not produce skew in the assembling process of process of transporting after making or battery.Therefore, the thickness of foils 11 is preferably about 10～50 μ m.As mentioned above, the important function of foils 11 is the supports as negative pole.Therefore when the intensity of current collection layer 3b is enough, or not to use foils to make negative pole 10.

As foils 11, the preferred material that uses with conductivity.In this case, if having conductivity, foils 11 can not be metal also.But, has after the making of negative pole 10 advantage of foils 11 being dissolved with foliation and utilizing again in addition by using metal foils 11.Under the situation of using metallic foils 11, preferably with containing Cu, Ni, Co, Fe, Cr, Sn, Zn, In, Ag, Au, at least a metal formation foils 11 among Al and the Ti.

As foils 11, can use and for example roll paper tinsel or electrolysis paper tinsel etc. by the paper tinsel that the whole bag of tricks makes, have no particular limits.From to the aperture of the fine voids the current collection layer 3b that forms in foils 11 and the viewpoint that exists density to control, the surface of foils 11 is preferably convex-concave shape to a certain degree.The calendering paper tinsel is owing to its manufacture method makes that its each face all is level and smooth.In contrast to this, the one side of electrolysis paper tinsel is rough, and other face is an even surface.Rough face is the face of separating out when making the electrolysis paper tinsel.Here, if on rough of the foils 11 that constitutes by the electrolysis paper tinsel, form current collection layer 3b, then saved foils has been carried out the time of roughening treatment in addition, so be easy.About using rough advantage back that description is arranged.Forming on such rough under the situation of current collection layer 3b, from can easily forming the aspect that has desired diameter and have the fine voids of density, its surperficial rough degree Ra (JIS B 0601) is preferably 0.5～5 μ m, particularly 0.2～0.8 μ m.

Then, on the one side of foils 11, impose remover and carry out lift-off processing.Preferably on rough of foils 11, impose remover.Remover is used at stripping process described later negative pole 10 successfully being peeled off from foils 11.As remover, preferably use organic compound, preferred especially nitrogen-containing compound or sulfur-containing compound.As nitrogen-containing compound, preferably use for example BTA (BTA), carboxyl benzotriazole (CBTA), tolyl-triazole (TTA), N ', N '-two (BTA ylmethyl) urea (BTD-U) and 3-amino-1H-1,2,4-triazole triazole class compounds such as (ATA).As sulfur-containing compound, can list: mercaptobenzothiazoler (MBT), thiocyanic acid (TCA) and benzimidazole mercaptan (BIT) etc.These organic compounds are dissolved into back use in alcohol, water, acid flux material, the basic solvent etc.For example under the situation of having used CBTA, preferably concentration is set at 2～5g/l.Concentration and coating amount by remover are controlled fissility.On the other hand, the peel ply that replacement is formed by organic compound, the mineral-type peel ply that is formed by chromium, lead, chromate processing etc. also is effective.The operation that applies remover is finally in order successfully to peel off negative pole 10 and to carry out from foils 11 in aftermentioned stripping process (Fig. 2 (g)).Therefore, also can in current collection layer 3b, form fine voids even save this operation.

Then, shown in Fig. 2 (b), on the remover (not shown) that applies, coating contains the coating liquid of electric conductive polymer and makes it dry formation films 12.Because coating liquid is applied on rough of foils 11, accumulate in this recess of rough easily.If solvent evaporates in this state, 12 the thickness of then the filming heterogeneity that becomes.That is, the coating thickness corresponding with rough recess is just big, and the coating thickness corresponding with protuberance is just little.In this manufacture method, utilize the inhomogeneity of 12 the thickness of filming, in current collection layer 3b, form a large amount of fine voids.

As electric conductive polymer, do not do special qualification for its kind, can use known in the prior art those.Can list: for example, poly-inclined to one side vinylidene fluoride (PVDF), poly(ethylene oxide) (PEO), polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) etc.Especially preferably use the lithium-ion-conducting polymer.And, the preferred fluorine-containing electric conductive polymer of electric conductive polymer.This be because, the thermal stability of fluoropolymer and chemical stability height, good aspect mechanical strength.Consider these factors, preferred especially the use as poly-inclined to one side vinylidene fluoride (PVDF) with fluoropolymer of lithium-ion-conducting.

The coating liquid that contains electric conductive polymer is dissolved in electric conductive polymer in volatile organic solvent and forms.Using under for example poly-situation of inclined to one side vinylidene fluoride (PVDF), preferably use the N-methyl pyrrolidone as organic solvents in particular as electric conductive polymer.

In this manufacture method, the mechanism that forms the current collection layer 3b with a large amount of fine voids on foils 11 is considered to as follows.Shown in Fig. 2 (c), formed 12 the foils 11 of filming and be implemented electroplating processes, thereby formed current collection layer 3b on 12 filming.This state is shown among the figure that wants portion's enlarged drawing (3) as Fig. 2 (c).Constitute 12 the electric conductive polymer of filming not as metal, but have electronic conductivity.Therefore, 12 the differences of filming according to its thickness, its electronic conductivity is also different.As a result, containing the filming on 12 by electroplating during precipitating metal of electric conductive polymer, making electrolysis go out speed according to the difference of electronic conductivity and produce difference, in current collection layer 3b, form fine voids 6 because electrolysis goes out the difference of speed.That is, promptly film 12 thick part of the part that speed of separating out is little forms fine voids 6 easily.In addition, as mentioned above, it is not necessary among the present invention forming fine voids in current collection layer, so do not form in current collection layer under the situation of fine voids, does not need to apply the operation of the coating liquid that contains electric conductive polymer.

As mentioned above, rough surperficial rough degree Ra by foils 11 can control the aperture of fine voids 6 and have density, in addition also can control the aperture of fine voids 6 and have density by the concentration that applies the electric conductive polymer that is contained in the liquid.For example under the rare situation of the concentration of electric conductive polymer, there is the tendency that diminishes in the aperture, and exists density that the tendency that diminishes is also arranged.On the contrary, for example under the dense situation of the concentration of electric conductive polymer, there is the tendency that becomes big in the aperture.From this viewpoint, the concentration of electric conductive polymer is preferably 0.05～5 weight % in coating liquid, is preferably 1～3 weight % especially.

Be used to form the plating bath of current collection layer 3b and plating condition and be according to the constituent material of current collection layer 3b and suitably select.For example under the situation that current collection layer 3b is made of copper, can use copper sulphate to bathe or the bath of cupric pyrophosphate copper with following composition as plating bath.Bath temperature when using these plating bath is preferably about 40～70 ℃, and current density is preferably 0.5～50A/dm ³About.

·CuSO ₄·5H ₂O 150～350g/l

·H ₂SO ₄ 50～250g/l

In addition, peeling agent layer that is made of organic substance and electric conductive polymer layer can also form with infusion process except forming with coating process.

Then, shown in following Fig. 2 (d), on current collection layer 3b the coating contain active material particle conductive paste and form active material layer 2.Slurry also contains particle, adhesive and the retarder thinner etc. of conductive carbon material except that the particle that contains active material.Among these compositions, be that the front is illustrated about the particle of active material and the particle of conductive carbon material.As adhesive, use poly-inclined to one side vinylidene fluoride (PVDF), polyethylene (PE), Ethylene Propylene Terpolymer diene monomers (EPDM), butadiene-styrene rubber (SBR) etc.As retarder thinner, use N-methyl pyrrolidone, cyclohexane etc.The amount of the particle of the active material in slurry is preferably about 14～40 weight %.The amount of the particle of conductive carbon material is preferably about 0.4～4 weight %.The amount of adhesive is preferably about 0.4～4 weight %.In these components, add retarder thinner and just make slurry.

Form active material layer 2 after making the dried coating film of slurry.The active material layer 2 that forms has a large amount of short spaces between particle.The foils 11 that has formed active material layer 2 is impregnated in the plating bath that contains the low metal material of lithium compound formation ability to electroplate.By being impregnated in the plating bath, plating bath is immersed in the above-mentioned short space of active material layer 2, and arrives the interface of active material layer 2 and current collection layer 3b.Electroplate in this state (below, be also referred to as this plating soak into plating).As a result, in the inside of (a) active material 2 and (b) in the inner face side of active material layer 2 (promptly with current collection layer 3b face side in opposite directions), lithium compound forms the low metal material of ability and separates out, and this material is impregnated into the whole thickness direction of active material layer 2.

Separate out in active material layer 2 in order to make lithium compound form the low metal material of ability, the condition of soaking into plating is important.For example using copper to form under the situation of the low metal material of ability as lithium compound, when using copper sulphate class solution, the concentration of copper is set at 30～100g/l, the concentration of sulfuric acid is set at 50～200g/l, the concentration of chlorine is set at below the 30ppm, the liquid temperature is set at 30～80 ℃, and current density is set at 1～10A/dm ³Get final product.Under the situation of using cupric pyrophosphate class solution, the concentration of copper is set at 2～50g/l, the concentration of potassium pyrophosphate is set at 100～700g/l, and the liquid temperature is set at 30～60 ℃, and pH is set at 8～12, and current density is set at 1～10A/dm ³Get final product.By suitably regulating these electrolytic conditions, lithium compound forms the low metal material of ability and separates out in the whole thickness direction zone of active material layer 2.Current density when the condition of particular importance is electrolysis.When current density is too high, do not separate out, only separate out on the surface of active material layer 2 in the inside of active material layer 2.

Then, on active material layer 2, form current collection layer 3a., because active material layer comprises the particle 2a of active material etc., so its surface is a matsurface.Therefore, in order to form current collection layer 3a,, in current collection layer 3a, also can form a large amount of fine voids 6 if adopt and the identical method of method that on rough of the foils 11 that constitutes by the electrolysis paper tinsel, forms current collection layer 3b.That is, coating contains the coating liquid of electric conductive polymer and makes it dry formation and films on the surface of active material layer 2.Then, the identical condition of condition when using with formation current collection layer 3b shown in Fig. 2 (e), forms current collection layer 3a by electroplating on this is filmed.In addition, as mentioned above, it is not necessary among the present invention forming fine voids in current collection layer, does not form in current collection layer under the situation of fine voids, does not need to apply the operation of the coating liquid that contains electric conductive polymer.

Then, shown in Fig. 2 (f), form perforation two current collection layer 3a, vertical hole 5 of 3b and active material layer 2 by perforation processing by regulation.Formation method for vertical hole 5 has no particular limits.For example can form vertical hole 5 by laser processing.Perhaps also can carry out mechanical perforation by pin or perforator (punch).Relatively the two uses laser processing to obtain cycle characteristics and the good negative pole of efficiency for charge-discharge easily.Its reason is, under the situation of laser processing, by the surface that processing is dissolved and cakey metal material has covered the active material particle of the wall that is present in vertical hole 5 again, directly expose so prevented active material, also just prevented that active material from coming off from the wall in vertical hole 5 thus.In addition, as the additive method that forms vertical hole 5, utilize sandblast processing or utilize the photoresist technology also can form vertical hole 5.Preferred vertically hole 5 forms in the mode that in fact equally spaced exists.This is because by doing like this, entire electrode can react equably.

At last, shown in Fig. 2 (g), foils 11 is peeled off and separated from collector body 3b.Obtain negative pole 10 thus.In addition, be described as in Fig. 2 (g), filming of electric conductive polymer remains in current collection layer 3b side, but this films 12 according to its thickness with to the kind of electric conductive polymer, sometimes residue in foils 11 sides, residue in current collection layer 3b side sometimes, perhaps also residue in their both sides sometimes.In addition, as mentioned above, negative pole 10 also can the suppressed by vector paper tinsel 11 supports, do not peel off from foils 11 till before using.

The negative pole of the present embodiment that obtains is like this used with known positive pole, barrier film, nonaqueous electrolyte and make nonaqueous electrolytic solution secondary battery.Positive pole is to make by following step: the suspension positive active material reaches conductive agent and the adhesive that just adds as required in appropriate solvent, make anode mixture thus, this anode mixture is coated on the collector body, after the drying, carrying out roll-in prolongs, punching press (press), again by cutting out, perforation and obtain positive pole.As positive active material, use existing known positive active material such as lithium nickel composite oxide, complex Li-Mn-oxide, lithium cobalt composite oxide.As barrier film, preferably use synthetic resin system nonwoven fabrics, polyethylene or polypropylene porous film etc.Under the situation that is lithium secondary battery, nonaqueous electrolytic solution is made of the solution of dissolving in organic solvent as the lithium salts of supporting electrolyte.As lithium salts, illustration for example has, LiClO ₄, LiAlCl ₄, LiPF ₆, LiAsF ₆, LiSbF ₆, LiSCN, LiCl, LiBr, LiI, LiCF ₃SO ₃, LiC ₄F ₉SO ₃Deng.

Then the 2nd execution mode of negative pole of the present invention is described with reference to Fig. 4.Point about the 2nd execution mode does not specify can be suitable for the explanation of being described in detail about the 1st execution mode aptly.And, in Fig. 4, for the member identical with Fig. 1～Fig. 3 with identical symbolic representation.

In the negative pole 10 of present embodiment,, have 2 negative pole presomas 20 and lithium metal layer 7 as its basic composition member.Lithium metal layer 7 is sandwiched between the negative pole presoma 20.

Negative pole presoma 20 possesses current collection layer 3 and is configured in active material layer 2 on the one side of this current collection layer 3.As shown in Figure 4, lithium metal layer 7 be clipped between the two negative pole presomas 20 so that the active material layer 2 in each negative pole presoma 20 toward each other and current collection layer 3 towards foreign side.Be held and be configured in two lithium metal layers 7 between the active material layer 2, in the presence of nonaqueous electrolytic solution, and constitute local cell between the active material (negative electrode active material).Thus, lithium metal forms lithium compound with being positioned near the active material generation chemical reaction the lithium metal layer.Perhaps cause lithium and active material reaction and form lithium compound by the concentration gradient of lithium.Like this, lithium metal layer 7 plays the effect as the supply source of lithium.As a result, even when charge and discharge cycles or long preservation, consumed lithium,, solved the problem of lithium exhaustion owing to supply with lithium from lithium compound with the reaction of electrolyte etc.Realized the long lifetime of negative pole 10 thus.Lithium metal layer 7 is not exposed to the surface of negative pole 10, and is positioned at the inside of negative pole 10, and because lithium and active material reaction form lithium compound, causes that internal short-circuit is also little with the possibility of the skeleton of the lithium that catches fire so generate.In the reacted lithium metal layer 7 of lithium, there is the reaction of lithium and active material and the lithium compound of generation volumetric expansion.

What be worth emphasizing is, also charges even negative pole 10 is assembled into battery, and the reaction of lithium metal and active material has just taken place.This phenomenon is that people of the present invention find for the first time.React by lithium metal and active material before the battery assembling, active material had become the state of volume increase before the battery assembling.Therefore, though after negative pole 10 be assembled into battery and discharge and recharge, minimum by the expansion rate that discharges and recharges caused negative pole 10.As a result, to play by the caused distortion of the change in volume of the active material that discharges and recharges generation be the extremely difficult so very favorable effect that takes place to the negative pole 10 of present embodiment.

From the viewpoint that the capacity recovery characteristics can become good, the amount of lithium metal is preferably 0.1～70% with respect to the saturated reversible capacity of active material, is preferably 5～30% especially.

Next with reference to Fig. 5 the preferred fabrication method of negative pole 10 is as shown in Figure 4 described.In addition, about the point that does not specify in this manufacture method, can be suitable for the explanation that manufacture method described in detail about as shown in Figures 2 and 3 aptly.At first, make negative pole presoma 20.In order to make negative pole presoma 20, shown in Fig. 5 (a), prepare foils 11.Then, as required, on the one side of foils 11, impose remover to carry out lift-off processing.Thereon, shown in Fig. 5 (b), coating contains the coating liquid of electric conductive polymer and makes it dry formation films 12.Then as Fig. 5 (c) shown in, filming on 12 of applying, the constituent material that goes out current collection layer 3 by the plating electrolysis forms current collection layer 3.On current collection layer 3, shown in Fig. 5 (d), coating contains the conductive paste of active material particle and forms active material layer 2.The dried coating film of slurry with after forming active material layer 2, is immersed in the foils 11 that has formed this active material layer 2 and contains in the plating bath that lithium compound forms the low metal material of ability to soak into plating.

Be formed on the negative pole presoma 20 that has possessed current collection layer 3 and active material layer 2 on the foils 11 successively and obtained thus.Shown in Fig. 5 (e), use such anticathode presoma, metallic lithium foil 30 is sandwiched between two negative pole presomas 20, so that the active material layer 2 in each negative pole presoma 20 is toward each other.Make them become as a whole by applying metallic lithium foil 30 with two negative pole presomas 20 thus.In this case, by only overlapping metallic lithium foil 30 and two negative pole presomas 20 and making the operation of their crimping that this three is fit together.Fit under the firm situation wanting to make, also can use conductivity jointing material such as conductivity paste that this three is fit together.Or, also can before a bonding anticathode presoma 20, separate and remove foils in advance.

Then, shown in Fig. 5 (f), a side foils is peeled off from current collection layer 3, current collection layer 3 is exposed.After one side's current collection layer exposes, shown in Fig. 5 (g), by fixed perforate be processed to form the vertical hole 5 that connects 3,3, two

active material layers

2,2 of two current collection layers and metallic lithium foil 30.In the end, shown in Fig. 5 (h), the opposing party's foils 11 is peeled off and separated from the opposing party's current collection layer 3.Obtain purpose negative pole 10 thus.

Next, with reference to Fig. 6～Fig. 9 the execution mode of the 3rd of negative pole of the present invention～5th is described.Point about not specifying in the 3rd～the 5th the execution mode can be suitable for the explanation of being described in detail about in the 1st and the 2nd the execution mode aptly.And, in Fig. 6～Fig. 9, for the member identical with Fig. 1～Fig. 5 with identical symbolic representation.

In the negative pole 10 of as shown in Figure 6 the 3rd execution mode, at a pair of current collection layer 3a, between the 3b, one deck active material 2 and layer of metal lithium layer 7 are disposed in clamping.Then, a large amount of vertical holes 5 that form the thickness direction that connects negative pole 10.Active material layer 2 and adjacent with it current collection layer 3a are equivalent to the negative pole presoma 20 in the negative pole of the 2nd execution mode.With the adjacent current collection layer 3a of active material layer 2 in form the fine voids (not shown) as required.On the other hand, with the adjacent current collection layer 3b of lithium metal layer 7 in do not form fine voids.

The negative pole 10 of the 4th execution mode as shown in Figure 7 possesses a pair of by active material layer 2 be adjacent the negative pole presoma 20 that the current collection layer 3 that connects constitutes.And possesses conductivity paper tinsel 8 at each face configuration lithium metal layer 7.Be held at the conductivity paper tinsel 8 that has disposed lithium metal layer 7 on each face and be configured between two negative pole presomas, make in each negative pole presoma 20 active material layer 2 toward each other and current collection layer 3 outwardly.In current collection layer 3, form the fine voids (not shown) as required.Also have a large amount of vertical holes 5 that form the thickness direction that connects negative pole 10.

The negative pole 10 of execution mode shown in Figure 7 is compared with the negative pole of execution mode shown in Figure 6, and only because possessed conductivity paper tinsel 8 this point, intensity has just increased.This is favourable when making the battery of gel-reel type.From this viewpoint, the thickness of conductivity paper tinsel 8 is preferably 5～20 μ m.Conductivity paper tinsel 8 generally is made of metal forming.As the material that constitutes conductivity paper tinsel 8, can list lithium compound and form the low metal material of ability.As such material, can use material that the front illustrated as current collection layer 3 be used to soak into electroplated metal material 4 identical materials.And from improving the viewpoint of intensity, it is effective using stainless steel foil and high strength calendering goldleaf.

The preferred fabrication method of the negative pole 10 of execution mode as shown in Figure 7 is as described below.At first, shown in Fig. 8 (a), prepare conductivity paper tinsel 8, on its each face, form lithium metal layer 7.Lithium metal layer 7 can for example form by vacuum vapour deposition by known film formation method.Therewith dividually, according to negative pole manufacture method by the 1st execution mode shown in Figure 2, make by active material layer 2 in advance and be adjacent the negative pole presoma 20 that the current collection layer 3 that connects constitutes, shown in Fig. 8 (b), the conductivity paper tinsel 8 that utilizes an anticathode precursor 20 will form lithium metal layer 7 sandwiches therebetween.Negative pole presoma 20 is supported by foils 11.When being sandwiched, make in each negative pole presoma 20 active material layer 2 toward each other, and outside current collection layer 3 faces.Then shown in Fig. 8 (c), a side foils 11 is peeled off from current collection layer 3, current collection layer 3 is exposed.After one side's current collection layer exposes, shown in Fig. 8 (d), by fixed perforate be processed to form the vertical hole 5 that connects two current collection layers 3,3, two active material layers 2,2, two lithium metal layers 7,7 and conductivity paper tinsel 8.In the end, shown in Fig. 8 (e), the opposing party's foils 11 is peeled off and separated from the opposing party's current collection layer 3.Obtain purpose negative pole 10 thus.

The negative pole 10 of execution mode as shown in Figure 9 is different with the negative pole institute of the execution mode that illustrates up to now, has collector body 9.Negative pole 10 has active material layer 2 on collector body 9.Because the negative pole of present embodiment 10 has collector body 9, there is no need on active material layer 2, current collection layer to be set.Active material layer 2 contains the particle 2a of active material, has soaked into lithium compound and form the low metal material 4 of ability between particle 2a.In negative pole 10, have that surperficial perforate at active material layer 2 forms and along a large amount of vertically holes 5 that the thickness direction of active material layer 2 extends.

Collector body 9 can use and the identical collector body that was used as the collector body of negative electrode for nonaqueous secondary battery in the past.Collector body preferably forms the low metal material of ability 4 by lithium compound and constitutes.The example of such metal material was described in the above.Especially preferably constitute by copper, nickel, stainless steel etc.Though the thickness of collector body 9 does not in the present embodiment have critical value, if when considering the intensity of keeping negative pole 10 and improving the balance of energy density, the thickness of preferred 10～30 μ m.

The negative pole 10 of present embodiment can enoughly be made with the similar method of negative pole manufacture method the 1st execution mode.At first, the slurry and forming that contains the particle 2a of active material in the coating of the one side of collector body 9 is filmed.Be immersed in the plating bath that contains the low metal material of lithium compound formation ability to electroplate having formed the collector body 9 of filming.Thus, form active material layer 2.In the end, active material layer is imposed perforate processing, thereby form a large amount of vertically holes 5 of extending along the thickness direction of active material layer 2 at active material layer 2.

In addition,, in addition also can form active material layer 2, form vertical hole 5 at each active material layer 2 on the two sides of collector body 9 though in the negative pole 10 of this example, only form active material layer 2 at the single face of collector body 9.And vertically hole 5 also can connect collector body 9.

More than be illustrated based on preferred implementation of the present invention, but the present invention is not limited to above-mentioned execution mode, can carry out various changes.For example, in the negative pole of the execution mode of representing as Fig. 9, also can use drawn metal as collector body.

Also can be in addition, on each face of the thick-film conductor body that the current collection that is called collector body in always being used to electrode is used, overlap negative pole presoma 20, form they vertical holes, thereby constitute negative pole in the past along its thickness direction perforation.

In addition, in the negative pole of Fig. 4 and execution mode shown in Figure 6, can not form vertical hole at lithium metal layer 7 yet.Similarly, in the negative pole of as shown in Figure 7 execution mode, in lithium metal layer 7 and conductivity paper tinsel 8, also can not form vertical hole 5.

In addition, the negative pole of each above-mentioned execution mode can use individually, perhaps also can be with this negative pole as the negative pole presoma, and a plurality of these negative pole presomas are stacked and used.In the latter case, also can be between adjacent negative pole presoma clamping be configured as the conductivity paper tinsel (for example metal forming) of core.

In addition, though in each above-mentioned execution mode current collection layer 3 (3a 3b) is single layer structure, in addition, also can make by 2 kinds of different sandwich constructions that constitute with the upper strata of material.For example by (3a 3b) makes the internal layer that is made of nickel and by outer field 2 layers of structure that copper constitutes, and can prevent effectively further that change in volume by active material from causing the obvious distortion of negative pole with current collection layer 3.

In addition, at current collection layer 3 (3a, material 3b) forms under the different situation of the low metal material of ability with lithium compound in being impregnated into active material layer, being impregnated into lithium compound in the active material layer forms the low metal material of ability and also may reside in active material layer 2 and current collection layer 3 (3a is till boundary member 3b).Or lithium compound forms the low metal of ability and also can cross this boundary member and constitute current collection layer 3 (3a, part 3b).On the contrary, current collection layer 3 (3a, also can cross this boundary member and be present in active material layer 2 by constituent material 3b).

Embodiment

Below, by embodiment the present invention is carried out more specific description, but the present invention is not limited to these embodiment.

Embodiment 1

According to method manufacturing negative pole as shown in Figure 1 as shown in Figure 2.At first, the copper foils that electrolysis is obtained (thick 35 μ m) was at room temperature used acid elution 30 seconds.At room temperature continue with pure water washing 30 seconds.Then, with dipping in the CBTA solution of the 3.5g/l of foils under remaining 40 ℃ state 30 seconds.Carry out lift-off processing thus.After the lift-off processing, from solution, mention, with pure water washing 15 seconds.

On rough of foils (the rough degree Ra=0.5 μ m in surface), apply by poly-inclined to one side vinylidene fluoride and be dissolved in the N-methyl pyrrolidone and the concentration that obtains is the coating liquid of 2.5 weight %.Solvent evaporates is impregnated into H with foils after forming and filming ₂SO ₄/ CuSO ₄Be to electroplate in the plating bath.Thus, on filming, formed the current collection layer that constitutes by copper.The composition of plating bath is CuSO ₄Be 250g/l, H ₂SO ₄Be 70g/l.Current density is set at 5A/dm ³Current collection layer forms with the thickness of 9 μ m.After from plating bath, mentioning, with pure water washing 30 seconds and dry in atmosphere.

Then, the slurry that coating contains the negative electrode active material particle on current collection layer forms active material layer thus to reach the thickness of 20 μ m.Active material particle is made of Si, and average grain diameter is D ₅₀=2 μ m.Consisting of of slurry, active material: acetylene carbon black: butadiene-styrene rubber=98: 2: 1.7.

After having formed active material layer, foils is immersed in watt (watt) bath with following bath composition, by electrolysis, active material layer is carried out the plating of soaking into of nickel.Current density is 5A/dm ³, bathing temperature is 50 ℃, pH is 5.Use nickel electrode as anode.Power supply uses DC power supply.This degree that the active material particle proceed to some exposes from plating face of electroplating of soaking into.After from plating bath, mentioning, with pure water washing 30 seconds and dry in atmosphere.

·NiSO ₄·6H ₂O 250g/l

·NiCl ₂·6H ₂O 45g/l

·H ₃BO ₃ 30g/l

Then, foils being immersed in Cu electroplates in the plating bath.Consisting of of plating bath, H ₃PO ₄Be 200g/l, Cu ₃(PO ₄) ₂3H ₂O is 200g/l.And the condition of plating is that current density is 5A/dm ³, bathing temperature is 40 ℃.Thus, on active material layer, formed the current collection layer that constitutes by copper.This current collection layer forms with the thickness of 8 μ m.After from plating bath, mentioning, with pure water washing 30 seconds and dry in atmosphere.

Then, the current collection layer irradiation YAG laser that forms on the active material layer forms vertical hole regularly.Vertically the hole is formed and connects two current collection layers and therebetween active material.Vertically the diameter in hole is set at 25 μ m, is set at 100 μ m (10000 holes/cm at interval ²).

In the end, with foils be attached thereto the current collection layer that connects and peel off, obtain being clamped in the negative electrode for nonaqueous secondary battery that forms between a pair of current collection layer by active material.The negative pole that obtains uses the outward appearance after preceding and 1 circulation of use to be shown in Figure 10.And the scanning electron microscope photo in the surface of the negative pole that obtains and vertical section is shown in Figure 11.According to the observed result of scanning electron microscope, the current collection layer of the side after affirmation is peeled off from foils on average has 30 minute apertures to exist in the square scope of 100 μ m * 100 μ m.

Embodiment 2

According to method manufacturing negative pole as shown in Figure 4 as shown in Figure 5.At first, on rough of foils (the rough degree Ra=0.5 μ m in surface), apply by poly-inclined to one side vinylidene fluoride and be dissolved in the N-methyl pyrrolidone and the concentration that obtains is the coating liquid of 2.5 weight %.Solvent evaporates is impregnated into H with foils after forming and filming ₂SO ₄/ CuSO ₄Be to electroplate in the plating bath.Thus, on filming, formed the current collection layer that constitutes by copper.The composition of plating bath is CuSO ₄Be 250g/l, H ₂SO ₄Be 70g/l.Current density is set at 5A/dm ³Current collection layer forms with the thickness of 5 μ m.After from plating bath, mentioning, with pure water washing 30 seconds and dry in atmosphere.

Then, the slurry that coating contains the negative electrode active material particle on current collection layer forms active material layer thus to reach the thickness of 15 μ m.Active material particle is made of Si, and average grain diameter is D ₅₀=2 μ m.Consisting of of slurry, active material: acetylene carbon black: butadiene-styrene rubber=98: 2: 1.7.

The foils that has formed active material layer is immersed in watt (watt) bath with following bath composition,, carries out the electrolysis of soaking into of nickel for active material layer by electrolysis.Current density is 5A/dm ³, bathing temperature is 50 ℃, pH is 5.Use nickel electrode as anode.Power supply uses DC power supply.This degree that the active material particle proceed to some exposes from plating face of electroplating of soaking into.After from plating bath, mentioning, with pure water washing 30 seconds and dry in atmosphere.

·NiSO ₄·6H ₂O 250g/l

·NiCl ₂·6H ₂O 45g/l

·H ₃BO ₃ 30g/l

The thickness that will prepare dividually with the negative pole presoma is that the metallic lithium foil of 25 μ m is clamped in the anticathode presoma.Sandwich is to carry out according to the active material layer that makes each negative pole presoma mode toward each other.Make the applying of each negative pole presoma and lithium metal make it into as a whole thus.

Then, a side foils is peeled off and current collection layer is exposed from current collection layer.Current collection layer irradiation YAG laser towards exposing forms vertical hole of running through each negative pole presoma and metallic lithium foil regularly.Vertically the diameter in hole is set at 25 μ m, is set at 100 μ m (10000 holes/cm at interval ²).In the end, the opposing party's foils and current collection layer are peeled off and obtained the purpose negative pole.The amount of lithium metal is 30% with respect to the saturated reversible capacity of active material on negative pole.

Embodiment 3

Make negative pole as shown in Figure 6.At first, according to embodiment 2 identical operations, obtain the negative pole presoma of supporting by foils.Then, with the negative pole presoma additionally, on the one side of the Copper Foil (current collection layer) of thickness 5 μ m, form the lithium metal layer of thick 10 μ m by vacuum vapour deposition.With this Copper Foil and the negative pole presoma made previously fit make it into as a whole.Applying is according to carrying out in the mode of lithium metal layer on the Copper Foil and the butt joint of the active material layer on the negative pole precursor.

Then, towards Copper Foil irradiation YAG laser, form vertical hole of running through Copper Foil and negative pole presoma regularly.Vertically the diameter in hole is set at 25 μ m, is set at 100 μ m (10000 holes/cm at interval ²).In the end, foils and current collection layer are peeled off and obtained the purpose negative pole.The amount of lithium metal is 25% with respect to the saturated reversible capacity of active material on negative pole.

Embodiment 4

According to method making negative pole as shown in Figure 7 shown in Figure 8.At first, according to embodiment 2 identical operations, obtain the negative pole presoma of supporting by foils.Then, with the negative pole presoma dividually, on each face of the Copper Foil of thickness 10 μ m, form the lithium metal layer of thick 10 μ m by vacuum vapour deposition.This Copper Foil is sandwiched between the negative pole presoma of making previously.Sandwich be according to the active material layer that makes each negative pole presoma toward each other and current collection layer carry out towards the mode of foreign side.The Copper Foil that makes each face all have the lithium metal layer thus makes it into as a whole with each negative pole presoma applying.

Then, a side foils is peeled off and current collection layer is exposed from current collection layer.Towards the current collection layer that exposes irradiation YAG laser, form regularly and run through vertical hole that each negative pole presoma and each face all have the Copper Foil of lithium metal layer.Vertically the diameter in hole is set at 25 μ m, is set at 100 μ m (10000 holes/cm at interval ²).In the end, the opposing party's foils and current collection layer are peeled off and obtained the purpose negative pole.The amount of lithium metal is 25% with respect to the saturated reversible capacity of active material on negative pole.

Embodiment 5

To obtain an anticathode presoma with embodiment 4 identical operations.The face irradiation YAG laser that exposes towards the active material layer on these negative pole precursors forms regularly and runs through vertical hole that each negative pole presoma and each face all have the Copper Foil of lithium metal layer.Vertically the diameter in hole is set at 25 μ m, is set at 100 μ m (10000 holes/cm at interval ²).

Then, will be sandwiched between the anticathode presoma that has formed vertical hole with the Copper Foil that has the lithium metal layer on the two sides that obtains with embodiment 4 identical operations.Sandwich be according to the active material layer that makes each negative pole presoma toward each other and current collection layer carry out towards the mode of foreign side.The Copper Foil that makes each face all have the lithium metal layer thus makes it into as a whole with each negative pole presoma applying.In the end, foils and current collection layer are peeled off and obtained the purpose negative pole.The amount of the lithium metal on negative pole is 27% with respect to the saturated reversible capacity of active material.

Embodiment 6

Except the diameter with vertical hole is set at 15 μ m, be set at 100 μ m (10000 holes/cm at interval ²) outside, obtain negative pole according to the step identical with embodiment 5.

Embodiment 7

Except the diameter with vertical hole is set at 25 μ m, be set at 200 μ m (2500 holes/cm at interval ²) outside, obtain negative pole according to the step identical with embodiment 5.

Embodiment 8

Except the diameter with vertical hole is set at 50 μ m, be set at 100 μ m (10000 holes/cm at interval ²) outside, obtain negative pole according to the step identical with embodiment 5.

Embodiment 9

Except the diameter with vertical hole is set at 50 μ m, be set at 200 μ m (2500 holes/cm at interval ²) outside, obtain negative pole according to the step identical with embodiment 5.

Embodiment 10

Except the diameter with vertical hole is set at 100 μ m, be set at 300 μ m (1111 holes/cm at interval ²) outside, obtain negative pole according to the step identical with embodiment 5.

Embodiment 11

Except the diameter with vertical hole is set at 250 μ m, be set at 1000 μ m (100 holes/cm at interval ²) outside, obtain negative pole according to the step identical with embodiment 5.

Embodiment 12

Except when making the negative pole presoma, using synthesized copper pyrophosphate bath, and following condition is soaked into plating bath to active material layer beyond, obtain negative pole according to the step identical with embodiment 5 with following composition.

Synthesized copper pyrophosphate bath

·K ₄P ₃O ₇ 450g/l

·Cu ₃P ₂O ₇ 105g/l

·KNO ₃ 15g/l

Soak into the condition of plating

Current density: 3A/dm ³

Bathe temperature: 55 ℃

·pH：8.2

Anode: DSE electrode

Embodiment 13

Except using the mechanical perforation that undertaken by perforator replacing YAG laser, obtain negative pole according to the step identical with embodiment 10 as the forming the method for vertical hole.

Embodiment 14

Except using the sandblast perforation replacing the formation method of YAG laser as vertical hole, obtain negative pole according to the step identical with embodiment 10.

Embodiment 15

Make negative pole as shown in Figure 9.Be that the slurry that coating contains the negative electrode active material particle forms active material layer thus to reach the thickness of 20 μ m on the one side of electrolytic copper foil of 18 μ m at thickness.Active material particle is made of Si, average grain diameter D ₅₀=2 μ m.Consisting of of slurry, active material: acetylene carbon black: butadiene-styrene rubber=98: 2: 1.7.Then, carry out the plating of soaking into of nickel for active material layer.The condition of soaking into plating is identical with embodiment 1.Active material layer irradiation YAG laser towards obtaining like this forms vertical hole regularly.Vertically the diameter in hole is set at 25 μ m, is set at 100 μ m (10000 holes/cm at interval ²).

Comparative example 1

On each face of the Copper Foil that obtains by electrolysis (thick 35 μ m), apply the slurry identical to reach the thickness of 15 μ m with the slurry of use among the embodiment 1, form active material layer thus, obtain negative electrode for nonaqueous secondary battery.

Performance evaluation

The negative pole that use obtains at embodiment and comparative example is made nonaqueous electrolytic solution secondary battery with following method.Measure and calculate the discharge capacity after 1 circulation of this battery with following method, the irreversible capacity after 1 circulation, the capacity sustainment rate after 100 circulations, efficiency for charge-discharge and negative pole thickness change after 100 circulations.These the results are shown in the following table 1.

The making of nonaqueous electrolytic solution secondary battery

The negative pole that will obtain in embodiment and comparative example uses LiCO as the work utmost point ₃As to the utmost point (positive pole), make the two poles of the earth across barrier film relatively to the ground setting.Use LiPF ₆The mixed solution of/ethylene carbonate and dimethyl carbonate (volume ratio 1: 1) is made nonaqueous electrolytic solution secondary battery as nonaqueous electrolytic solution by usual way.The Capacity Ratio that battery is made into anodal and negative pole is 1: 1 and 1: 2 two kinds.The Capacity Ratio of using anodal and negative pole is discharge capacity after 1 circulation of battery mensuration of 1: 1 and the irreversible capacity after 1 circulation.The Capacity Ratio of using anodal and negative pole is the capacity sustainment rate after 100 circulations of battery mensuration of 1: 2, efficiency for charge-discharge and negative pole thickness change after 100 circulations.

Discharge capacity after 1 circulation

Measure the discharge capacity of per unit weight and per unit volume.The discharge capacity of per unit weight is a benchmark with active material (Si).The discharge capacity of per unit volume is a benchmark with the volume of negative pole.But, the expansion of negative pole when not considering to charge.

Irreversible capacity after 1 circulation

Irreversible capacity (%)=(the first discharge capacity of 1-/primary charging capacity) * 100

That is, be illustrated in and do not discharge after the charging and remain in capacity in the active material.

Capacity sustainment rate after 100 circulations

Measure the discharge capacity after 100 circulations, divided by maximum negative discharge capacity, multiply by 100 and calculate again with this value.

Efficiency for charge-discharge after 100 circulations

Charging capacity * 100 after discharge capacity/100 circulation after efficiency for charge-discharge (%)=100 circulation after 100 circulations

The negative pole thickness change

Use the system HS of precious Izumi Ltd. displacement transducer, be determined at that negative pole is accompanied by the varied in thickness that charging takes place in 1 circulation.This displacement transducer is to measure negative pole+barrier film+anodal LiCoO ₂Whole varied in thickness.But because positive pole expands along with discharging and recharging hardly, the contribution rate of the varied in thickness of negative pole is very big, and in fact the varied in thickness of mensuration can be considered as the varied in thickness of negative pole.The negative pole thickness change is calculated by following formula.

Thickness * 100 before negative pole thickness change (%)=[(thickness of 1 cycle charging state)-(thickness before the charging)]/charging

[table 1]

	Discharge capacity after 1 circulation ^*1mAh/g	Discharge capacity after 1 circulation ^*2mAh/cm ³	Irreversible capacity % after 1 circulation	Capacity sustainment rate % after 100 circulations	Efficiency for charge-discharge % after 100 circulations	Negative pole thickness change %
	Discharge capacity after 1 circulation ^*1mAh/g	Discharge capacity after 1 circulation ^*2mAh/cm ³	Irreversible capacity % after 1 circulation	Capacity sustainment rate % after 100 circulations	Efficiency for charge-discharge % after 100 circulations	Negative pole thickness change %	Embodiment 1	3500	1842	10	85	99.5	30
Embodiment 2	3800	1754	3	90	100	13	Embodiment 1	3500	1842	10	85	99.5	30
Embodiment 2	3800	1754	3	90	100	13	Embodiment 3	3800	1629	3	92	99.9	10
Embodiment 4	3900	1671	3	95	100	8	Embodiment 3	3800	1629	3	92	99.9	10
Embodiment 4	3900	1671	3	95	100	8	Embodiment 5	3850	1650	3	95	100	10
Embodiment 6	3800	1677	4	87	99.8	13	Embodiment 5	3850	1650	3	95	100	10
Embodiment 6	3800	1677	4	87	99.8	13	Embodiment 7	3800	1687	4	86	99.8	12
Embodiment 8	3750	1364	5	80	99.6	15	Embodiment 7	3800	1687	4	86	99.8	12
Embodiment 8	3750	1364	5	80	99.6	15	Embodiment 9	3850	1650	3	96	100	7
Embodiment 10	3850	1577	3	92	99.9	10	Embodiment 9	3850	1650	3	96	100	7
Embodiment 10	3850	1577	3	92	99.9	10	Embodiment 11	3800	1629	5	85	99.6	18
Embodiment 12	3850	1650	3	97	100	9	Embodiment 11	3800	1629	5	85	99.6	18
Embodiment 12	3850	1650	3	97	100	9	Embodiment 13	3700	1516	5	81	99.2	10
Embodiment 14	3700	1516	6	85	99.5	10	Embodiment 13	3700	1516	5	81	99.2	10
Embodiment 14	3700	1516	6	85	99.5	10	Embodiment 15	3500	1793	10	80	99.3	30
Comparative example 1	1900	570	30	5	98	160	Embodiment 15	3500	1793	10	80	99.3	30

^*1: per unit weight active material (Si)

^*2: negative pole per unit volume (expansion when still not considering to charge)

Result just as shown in table 1 clearly show like that, the discharge capacity of the cell that can distinguish the negative pole that has used each embodiment is high, and irreversible capacity is little.Distinguish that also capacity sustainment rate and efficiency for charge-discharge also are high.The thickness change of also distinguishing negative pole is little.

As above described in detail, according to the present invention, in vertical hole that the active material thickness direction extends because can fully alleviate active material owing to discharging and recharging the caused stress of the change in volume that takes place, so can prevent the obvious distortion of negative pole effectively.Therefore, prolong the cycle life of negative pole significantly, also improved efficiency for charge-discharge.And, because metal material is separated out between the particle of active material in active material layer, so, prevented effectively that still electric isolated active material from existing, and can access sufficient current collection even active material particle owing to discharging and recharging micronizing takes place.

Claims

1, negative electrode for nonaqueous secondary battery, this negative pole possesses the active material layer of the particle that contains active material, in this active material layer, the metal material of separating out by plating is impregnated between the particle, and described negative pole has a large amount of vertically holes, and the perforate on the one side at least of described negative pole of this vertical hole forms and extends along the thickness direction of described active material layer.

2, negative electrode for nonaqueous secondary battery according to claim 1, it also possesses and the contacted current collection layer of electrolyte, described active material layer is configured in than this current collection layer more in the inner part, and extend along the thickness direction of described current collection layer and described active material layer in described vertical hole.

3, negative electrode for nonaqueous secondary battery according to claim 2, it has a pair of described current collection layer and is held the described active material layer that is configured between this current collection layer.

4, negative electrode for nonaqueous secondary battery according to claim 3, the thickness one of at least of wherein said a pair of current collection layer is 0.3～10 μ m.

5, negative electrode for nonaqueous secondary battery according to claim 4, the thickness of wherein said a pair of current collection layer 0.3～10 μ m that respectively does for oneself.

6, negative electrode for nonaqueous secondary battery according to claim 3, it also possesses a pair of described current collection layer, is held the described active material layer and the lithium metal layer that are configured between this current collection layer.

7, negative electrode for nonaqueous secondary battery according to claim 6, it possesses a pair of described active material layer, and described lithium metal layer is disposed in clamping between this active material layer.

8, negative electrode for nonaqueous secondary battery according to claim 7, it possesses a pair of described lithium metal layer, and the conductivity paper tinsel is disposed in clamping between this lithium metal layer.

9, negative electrode for nonaqueous secondary battery according to claim 1, wherein the percent opening in described vertical hole that the surperficial perforate of negative pole forms is 0.3～30%.

10, negative electrode for nonaqueous secondary battery according to claim 1, wherein the perforate in described vertical hole that the surperficial perforate of negative pole forms directly is 5～500 μ m.

11, negative electrode for nonaqueous secondary battery according to claim 1, wherein said vertical hole connects at the thickness direction of negative pole.

12, negative electrode for nonaqueous secondary battery according to claim 1, wherein vertically the hole forms by laser processing.

13, negative electrode for nonaqueous secondary battery according to claim 1, wherein vertically the hole forms by mechanical perforation.

14, negative electrode for nonaqueous secondary battery is characterized in that, it is to use the described negative pole of claim 1 as the negative pole presoma, and by a plurality of this negative pole presoma is stacked forms.

15, negative electrode for nonaqueous secondary battery according to claim 14, wherein the conductivity paper tinsel is disposed in clamping between adjacent described negative pole presoma.

16, nonaqueous electrolytic solution secondary battery is characterized in that, possesses the described negative pole of claim 1.