CA2358244C

CA2358244C - Non-aqueous electrolyte cell having strip-shaped cathode and anode materials

Info

Publication number: CA2358244C
Application number: CA2358244A
Authority: CA
Inventors: Hideki Sakai; Yuzuru Fukushima; Junji Kuyama; Mamoru Hosoya
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2000-10-06
Filing date: 2001-10-03
Publication date: 2010-08-10
Anticipated expiration: 2021-10-03
Also published as: EP2267822B1; TW523945B; EP2267822A1; CN1314157C; US20020150816A1; CN1348230A; EP1195838A2; CA2358244A1; US6991873B2; JP2002117908A; KR100865242B1; EP1195838B1; EP1195838A3; KR20020027274A; MXPA01009972A

Abstract

A non-aqueous electrolyte cell having high discharge capacity, an improved capacity upkeep ratio and optimum cyclic characteristics. The non-aqueous electrolyte cell has a cell device including a strip-shaped cathode material and a strip- shaped anode material, layered and together via a separator and coiled a plural number of times, a non-aqueous electrolyte solution, and a cell can for accommodating cell device and the non-aqueous electrolyte solution. The cathode employs a cathode active material containing a compound of the olivinic structure represented by the general formula Li x Fe1-y M y PO4, where M is at least one selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05 <= x <= 1.2 and 0 <= y <= 0.8, with the compound being used either singly or in combination with other materials. The ratio of an inner diameter d to an outer diameter D of cell device is selected so that 0.05 < d/D < 0.5.

Description

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TITLE OF THE INVENTION
Non-Aqueous Electrolyte Cell BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a non-aqueous electrolyte cell employing a cell device obtained on layering and coiling a strip-shaped cathode material and a strip-shaped anode material together. More particularly, it relates to improvement in a cell device.
Description of Related Art Nowadays, in keeping up with the recent marked progress in the electronic equipment, researches into re-chargeable cells, as power sources usable conveniently and economically for prolonged time, are underway. Representative of the cells are lead accumulators, alkali accumulators and non-aqueous electrolyte cells.
Ofthe above cells, lithium ion secondary cells, as non-aqueous electrolyte cells, have such merits as high output and high energy density.
The lithium ion secondary cells are made up of a cathode and an anode, including active materials capable of reversibly doping/dledoping lithium ions, and a non-aqueous electrolyte. The charging reaction of the lithium ion cell proceeds as lithium ions are deintercalated into an electrolyte solution at the cathode and are intercalated into the anode active material. In discharging, reaction opposite to that of the charging reaction proceeds, such that lithiwn ions are interecalated at the cathode.
That is, chargin.g/discharging is repeated as the reaction of entrance/exiting of lithium ions fi-om the cathode into the anode active material and fi-om the anode active material occurs repeatedly.
Cun-ently, LiCo02, LiNiOz or LiMn20~, are used as the cathode active material of the lithium ion secondary cell because these materials exhibit a high energy density and a high voltage.
However, if the aforementioned active material is used, both the cathode material and the anode material undergo volumetric expansion and contraction, during charging and discharging, respectively, thus producing marked volumetric changes.
Thus, if, in case of a cell accommodating the electrolyte solution and the cell device in an iron cell can, the cathode and anode materials are layered and coiled together to form a cell device, the cathode acid anode materials are coiled to too small an inner diameter, the layers of the cathode active material or the anode active material in the vicinity of the center of the coil tend to be deteriorated, peeled of or detached due to the volumetric changes of the cell device during charging/discharging, thus causing internal shorting or deteriorating the volumetric upkeep ratio to render it impossible to realize satisfactory cyclic characteristics.
Moreover, depending on the structure of the cell device, specifically the value of the ratio of the inner diameter d to the outer diameter D, or d/D, the amount of the active material introduced into the cell device cannot be counterbalanced with respect to the amount of the electrolyte solution to render it impossible to realize a high discharge capacity.

SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a non-aqueous electrolyte cell which, when the cathode and anode materials are layered and coiled together to f01771 a cell device, which is then housed in a cell can along with the electrolyte solution, is ofhigh capacity and is improved in the volumetric upkeep ratio.
The present invention provides a non-aqueous electrolyte cell C0117p1'1s1I1g a cell device including a strip-shaped cathode material and a strip-shaped anode material, which are layered via a separator and coiled a plural nuanber of times, a non-aqueous electrolyte solution, and a cell can for accommodating the cell device and the non-aqueous electrolyte solution, wherein said cathode material employs a cathode active material containing a compound of an olivinie structure represented by a general formula Li,,Fel_~,M~,P04, where M is at least one selected from a group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05 s x <_ 1.2 and 0 _< y < 0:8, which compound is used either singly or in combination with other materials, and wherein a ratio of an inner diameter d to an outer diameter D
of said cell device is 0.05 <d/D< 0.5.
With the non-aqueous electrolyte cell according t:o the present invention, the aforeW entioned compound used in the cathode active material suppresses volumetric changes of the cell device in charging/discharging to enahle the inner diameter of the coiled cell device to be reduced. Thus, according to the present invention, in which the aforementioned compound is used as the cathode active material and by setting a v preset range for the ratio of the imer diameter d to the outer diameter D of the cell device, a high discharge capacity as well as a high capacity upkeep ratio may be achieved.
BRIEF DESCRIPTION OF THE DRAWING
Fig.l is a cross-sectional view showing a non-aqueous electrolyte cell embodying the present invention, with a portion thereof being broken away.
Fig.2 is a cross-sectional view showing essential portions of a cell device ofthe cell shown in Fig.1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, certain preferred embodiments of the present invention will be explained in detail.
Refen-ing to Fig.l, a non-aqueous electrolyte cell 1 includes a strip-shaped cathode material 2 and a strip-shaped anode material 3, layered together via a separator 4, and spirally coiled a plural number of times to form a cell device 5, which is housed along with the non-aqueous electrolyte solution in a cell cari 6.
The cathode material 2 is made up of a cathode current collector 7, formed e.g., by an aluminum foil, on both sides of which are formed layers of a cathode active material 8 containing a cathode active material capable of reversibly electrically emitting and occluding lithium. A cathode lead 9 is mounted in the vicinity of one end of the cathode material 2 The cathode active material contained in the layers of the cathode active material 8 is a compound of an olivinic crystal structure represented by the general formula Li~Fe~_~,M~,PO~ where m denotes at least one of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05 _< x _< 1.2 and 0 <_ y <_ 0.8. This compound may be used either alo~~e or in combination. 1n the present embodiment; a composite material composed of LiFeP04 as later explained in detail and a carbon material is used as a cathode active material. In the following, a case of using LiFePOa as Li,Fe~_ ~,M~,PO~, and of using a composite material of LiFePOa and a carbon material as cathode active material is explained.
The composite material of LiFePO~ and a carbon material, referred to below simply as LiFeP04 carbon composite material, is such a material composed of LiFeP04 particles on the surfaces of which are attached numerous particles of the carbon material having the particle size appreciably smaller than the particle size of the LiFeP04 particles. Since the carbon material is electrically conductive, the LiFePO~, carbon composite material, composed of the carbon mai:erial and LiFeP04, is higher in electronic conductivity than a cathode active material composed e.g., only of LiFeP04. That is, since the LiFeP04 carbon composite material is improved in electronic conductivity due to the carbon particles attached to the LiFeP04 particles, the capacity proper to LiFeP04 can be sufficiently manifested: Thus, by using the LiFeP04 carbon composite material as the cathode active material, the non-aqueous electrolyte cell 1 having a high capacity can be achieved. , The carbon content per unit weight in the LiFeP04 carbon composite material is desirably not less than 3 wt%. If the carbon content per unit weight of the LiFePO~
carbon composite material is less than 3 wt%, the amount of carbon particles attached to LiFePO~ may be insufficient so that no favorable effect.in improving the electronic conductivity may be realized satisfactorily.
As the carbon material forming the LiFeP04 carbon composite material, such a material is preferably used which has an intensity area ratio of diffi-acted beams appearing at the number of waves of 1570 to 1590 cam-' to the diffracted beams appearing at the number of waves of 1340 to 1360 cm-' in the Raman spectrum of graphite in the Raman spectroscopy, or the ratio A(D/G), equal to 0.3 oz' higher.
The strength area ratio A(D/G) is defined as being a background-free Raman spectral 'intensity area ratio A(D/G) of a G-peak appearing at~the number of waves of 1570 to 1590 cW ' and a D=peak appearing at the number of waves of 1340 to 1360 cW
' as measured by the Raman spectroscopic method as shown in Fig.2. The expression "background-free" denotes the state free from noisy portions. .
Among the numerous peaks of the Raman spectuum of Gr, two peaks, namely a peak termed a G-peak appearing at the nwnber of waves of 1570 to 1590 cW ' and a peak termed a D-peak appearing at the number of waves of 1340 to 1360 cm-', as discussed above, may be observed. Of these, the D-peak is not a peak inherent in the G-peak, but is a Raman inactive peak appearing when the structure is distorted and lowered in symmetry. So, the D-peak is a measure of a dvstorted structure of Gr. In a known manner, the intensity area ratio A (D/G) of the D- and G-peaks is proportionate y i to a reciprocal of the crystallite size La along the axis a of Gr.
As such carbon material, an amorphous carbon material, such as acetylene black, is preferably employed.
The carbon material having the intensity area ratio A (D/G) not less than 0.3 may .be obtained by processing such as comminuting with a pulverizing device.
A
carbon material having an arbitrary ratio A (D/G) may be realized by controlling the pulverizing time duration.
For example, graphite, as a crystalline carbon material, may readily be destroyed in its structure by a powerful pulverizing device, such as a planetary ball mill, and thereby progressively amoiphized, so that the intensity area ratio A
(D/G) is concomitantly .increased. That is, by controlling the driving .time .duration of a pulverizing device, such a carbon material having a desired A (D/G) value not less than 0.3 may readily be produced. Thus, subject to pulverization, a crystalline carbon material may also be preferably employed as a carbon material:
The powder density of the LiFeP04 carbon compo site material is preferably not less than 2.2 g/cm3. If the material for synthesis of the LiFeP04 carbon composite material is milled to such an extent that the powder density is not less than 2.2 g/cm3, .
the resulting LiFeP-04 carbon composite material is coiruninuted sufficiently so that a non-aqueous electrolyte cell 1 having a higher charging ratio of the cathode active material and a high capacity may be realized. Moreover, since the LiFeP04 carbon composite material is comminuted to satisfy the aforementioned powder density, its specific surface may be said to be increased. That is, a sufficient contact area may be maintained between LiFePO~ and the carbon material to improve the electronic conductivity.
If the powder density of the LiFePO~ carbon composite material is less than 2.2 g/cm~, the LiFePO~ carbon composite material is not compressed sufficiently, so that there is a risk that the packing ratio of the active material cannot be improved at the cathode material 2.
On the other hand, the Brunauer-Enunet-Teller (BET) specific surface area in the LiFeP04 carbon composite material is preferably not less than 10.3 mz/g.
If the BET specific surface area of the LiFePO~, carbon composite material is not less than 10.3 mz/g, the surface area of LiFeP04 per unit weight c;an be sufficiently increased to increase the contact area between LiFeP04 and the carbon material to improve the electronic conductivity of the cathode active material satisfactorily.
The primary particle size of the LiFeP04 carbon composite material is preferably not larger than 3.1 pm. By the primary particle size of the LiFeP04 carbon composite material being not larger than 3.1 pm, the surface area of LiFeP04 per unit - area W ay be. sufficientlyincreased to increase the contact area between LiFeP04 and the carbon material to improve the electronic conductivity of,the cathode active material.
In the present embodiment, the LiFeP04 carbon composite material is used as the.cathode active material. However, the present invention is not limited thereto. Ill the present invention, LiFePOa by itself may be used as the cathode active material, or a compound represented by the general formula Li,Fei_~,M~,PO~,, other than LiFePO~,, where M is at least one selected fi-om the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05 <_x<_ 1.2 and 0<_y<_0.8, may be used as the cathode active material either singly or in combination with other materials.
These compounds may be enumerated by, for example, LiFeo.2Mno.xPO~,, LiFeo.zCl'o.sPOa, LiFeo.ZCoo.~PO~,, LiFeo.2Cuo.8P0~, LiFeo.2Nio.~PO~, LiFeo.2sVo.~5P04;
LiFeo,25Moo.~5P0~, LiFea.25Tio.~sPO~, LiFeo.3Zno.~PO~, LiFeo.3Alo.~PO~,, LiFeo.3Gao.~POa, LiFeo.25Mgo.~SPOa, LiFeo.2sBo.~sP04 and LiFeo.zsNbo.~sPO4.
The binder contained in the layer ofthe cathode active material may be forned of any suitable known resin material routinely used as the binder for the layer of the cathode active material for this sort of the non-aqueous electrolyte cell.-An anode material 3 is made up of an anode curre:r~t collector 10, formed e.g., by a nickel foil or a copper foil; and a layer of an anode active material .l 1 forned on each surface of the anode current collector 10. An anode lead 12 is mounted to the vicinity of the anode material 3.
The anode active material of the layer of the anode active .material l l is such a material capable of doping/dedoping lithium. As thus anode active material, capable of doping/dedoping lithium, metal lithium, lithium alloys, lithium-doped electrically conductive high molecular materials, carbonaceous materials or layered compounds, such as metal oxides, can be used. The binder contained in the layer of the anode active material 11 may be any suitable lUloWIl blllder routinely used in this sort of the non-aqueous electrolyte cell.
In the non-adueous electrolyte cell 1, if the positions of the width-wise ends of the anode material 3 are coincident with or inwardlyoffset with respect to the width-wise ends ofthe cathode material 2, lithium ions emitted from the cathode material 2 in the vicinity or on the outer side of the width-wise ends of the anode material 3 during charging tend to be affected in charging/discharging balance at both width-wise ends of the anode material 3, with the lithium ions being then precipitated as metal lithium obstructing the charging/discharging reaction to render it impossible to produce sufficient charging/discharging cyclic characteristics.
Thus, in the non-aqueous electrolyte cell 1, the anode material 3 is set so as to :be of broader width than the cathode material 2 to render it difficult for the lithium ions to be affected in charging/discharging balance in the portions of the anode material 3 facing the both.width-wise ends or the vicinity of the both width-wise ends of the cathode material 2 to render the precipitation of the lithium ions difficult. In the non-aqueous electrolyte cell l, since the amount of Li emitted in charging to a high potential exceeding 4 V is appreciably smaller with LifeP04 used as its cathode active material than with 4V class cathode active material, such as LiCo02, metal lithium is less liable to be precipitated in the portions of the anode material 3 facing both width-wise ends or the vicinity of the width-wise ends of the cathode material 2.
If one end of the anode material 3 is larger. by 0.05 mm or- more than the -l0 corresponding end of the cathode material 2, Chal'~T111gIdlSCIIaI'glilg may be obtained, whereas, if the one end of the anode material 3 is larger by less than 0.05 mm than the corresponding end of the cathode material 2, the end of the anode material 3 tends to be coincident with or inwardly offset with respect to tlne con-esponding end of the cathode material 2. If the width at one end of the anode material ~ is larger by 2.0 ~nm or anore than the that at the con-esponding end of the cathode material 2, the amount of the anode active material not contributing to the cell reaction is increased to lower the energy density of the cell. It is therefore desirable that the anode material 3 is broader in width than the cathode material 2 so that a difference t in the width-wise dimension on one side shown in Fig. l be in a range of 0.05 mm to 2.0 mm.
The separator 4 seines for separating the layer of the cathode active material of the cathode material 2 from the layer of the anode active material 11 of the anode material 3, and may be formed by a film of any suitable ltr~own material routinely used as a separator for this sort of the non-aqueous electrolyte cell, such as; for example, a film of a high molecular material, e.g., polypropylene. The separator 4 needs to be as thin in thickness as possible in view of the relation between the lithium ion conductivity and the energy density. Specifically, the separator thickness of, for example, 50 pin or less, is desirable.
In the non-aqueous electrolyte cell 1, the aforementioned cathode material 2 and the anode material.3 are layered together via separator 4., and coiled a plural number of times to form the cell device 5, as shown in Figs:l and 2. The cell device 5 is produced by coiling the cathode material 2 and the anode material 3 so that the ratio of the inner diameter d to its outer diameter D, or d/D, will be such that 0.05<d/D<0.5.
The non-aqueous electrolyte cell 1 uses LiFePO~, having the olivinic crystal stmcture, as the cathode active material, as discussed above. This LiFePO~ has properties opposite to those of the carbon material used for an anode active material;
that is the properties that its crystal lattice volume is decreased and increased during the charging when Li is dedoped and during discharge when Li is doped, respectively. Thus, in the non-aqueous electrolyte cell l, the cell device 5 undergoes volumetric changes due to charging/discharging only to a lesser extent than if a conventional material such as LiCo02 is used as the cathode active material. Thus, if tl-ie imier diameter d of the cell device 5 is decreased, with its outer diameter D remaining unchanged, and the charging/discharging is performed a plural number of times, deterioration of electro-chemical properties, peeling or detaclunent of the active material due to volumetric expansion or contraction of the device may be suppres sed to improve the capacity upkeep ratio to realize optimum cyclic characteristics.
The reason of setting the ratio of the inner diameter d to its outer diameter D, or d/D, so that 0.05<d/D<0.5, is that, if the ratio is not less than 0.5, the inner diameter d is so large that an excess amount of the electrolyte solution is introduced, whilst an amount necessary .and. sufficient for the cell reaction cannot be charged so that the practical capacity of the cell cannot be maintained. The. reason.of setting.
the lower limit of the ratio d/D of the inner diameter d and the outer diameter D to 0.05 is that, if the ratio is larger than 0.05, the aforementioned deterioration of electro-chemical properties, peeling or detachment of the active material due to volumetric expansion or contraction of the device .is not produced, whereas, if the ratio is not larger than 0.05, the aforementioned deterioration of electro-chemical properties, peeling or detaclvnent of the active material is actually produced.
As the non-aqueous electrolyte solution, such a solution obtained on dissolving an electrolyte in a non-protonic aqueous solvent is used.
As the non-aqueous solvent, propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, 'y-butyrolactone, sulfolane, l, 2-dimethoxyethane, l, 2-diethoxyethane, 2-methyl tetrahydrofuran, 3-methyl-1,3-dioxolane, methyl propionate, methyl.butylate; dimethyl carbonate; diethyl carbonate and dipropyl carbonate, for example, may be used. In view of voltage stability, cyclic carbonates, such as propylene carbonate, ethylene carbonate, buty:lene carbonate or vinylene carbonate, and chained carbonates, such as dimethyl carbonate; diethyl carbonate and dipropyl carbonate, are preferably used. These non=aqueous solvents may be used alone or in combination.
As the electrolytes dissolved in the non-aqueous solvent, lithium salts; such as LiPF~, LiC104, LiAsF~, LiBF4; LiCF3S03 or LiN(CF3S02)2, may be ~ used. Of these.
lithium salts, LiPF~ and LiBF4 are preferred.
- The cell can 6, the firmer surface of which is plated with nickel, is used for housing the cell device 5 and the non-aqueous electrolyte.

The method for the preparation of the non-adueous electrolyte cell l, constl-llcted as descl-ibed above, is hereinafter explained.
First, a composite material of LiFePO~ and the carbon material, as a cathode active material, is synthesized by a manufacturing method as now explained.
.. For synthesizing the cathode active material, LiFePO~ as a stal-ting material for synthesis is kneaded together, milled and sintered. At an optional time point in the.
course of the mixing, milling and sintering, a carbon material is added to the kneaded starting. materials for synthesis. As the LiFeP04 Staltlllg materials for synthesis, Li3P04, Fe3(P04)2 or a hydrate Fe3(POa)2 wH20 thereof where n denotes the number of hydrates, are used.
In the following, such a case is explained in which lithium phosphate Li3P0~
and a ferrous phosphate octahydrate Fe3(PO~)2 ~8H20 thereof, 'synthesized as explained below, are used as starting materials for synthesis, and in which, after adding a carbon lnaterial to these starting materials for synthesis, a number ofprocess steps are carried out to synthesize the LiFeP04 carbon composite material.
First, the LiFeP04 starting materials for synthesis. and the carbon material are mixed together .to form a mixture by way of a mixing step. The mixture from the mixing step is then milled by a milling process, and the milled mixture then is sintered by way of performing a sintering process.
In the mixing process, lithium phosphate and ferrous phosphate octahydrate are mixed together at a pre-set ratio and further added to with a carbon material to form a mixture.
This fen-ous phosphate octahydrate, used as a starting material for synthesis, is synthesized by adding disodium hydrogen phosphate dodecahydrate (2Na2HPOy 12H20) to an adueous solution obtained on dissolving fewous phosphate heptahydrate (FeSOy7H20) in water and by allowing the resulting mass to dwell for a pre-set time. The reaction of synthesis of fen-ous phosphate octahydrate may be represented by the following chemical founula ( 1 ):
3F.eS0y7H20 + 2NaZHPOy 12H20 -~ Fe3(PO~)2~8H20 + 2Na2S04 + 37H20 ...( I ).
In ferrous phosphate octahydrate, as the material for synthesis, there is contained a certain amount of Fe3+ from the synthesis process. If Fe3~ is left in the material for synthesis, a trivalent Fe compound is generated by sintering to obstruct single-phase. synthesis of the LiFeP04 carbon composite material. It is therefore necessary. to add a reducing agent to the starting materials for synthesis prior to sintering and to reduce Fe3+ contained in the starting materials for synthesis to Fe2+ at .
the time of sintering.
However, there is a limitation to the capability of the reducing agent in reducing Fe3+ to Fe2+~ by the reducing agent, such that, if the content of Fe3~ in the starting materials for synthesis is excessive, it may be an occurrence that Fe3+ is not reduced in its entirety but is left in the LiFePO~ carbon composite material:
It is therefore desirable that the content of Fe3~ in the total iron in the ferrous phosphate octahydrate be set to 61 wt% or less. By limiting the content of Fe~* in the total iron in the fem-ous phosphate octahydrate to 61 wt% or less fi-om the outset, single-phase synthesis oftlze LiFePOa carbon composite material can be satisfactorily achieved without allowing Fe3l to be left at the time of sintering, that is without generating impurities ascribable to Fey+.
It should be noted that, the longer the dwell time in generating fewous phosphate octahydrate, the larger becomes the contemt of Fe3+ in tile generated product, so that, by controlling the dwell time so as to be edual to a preset time, ferrous phosphate octahydrate having an optional Fe3+ can be produced. The coaltent of Fe3+ in the total iron in the ferrous phosphate octahydrate can be measured by the Mossbauer method.
The carbon material added to the starting materials for synthesis acts as a reducing agent for reducing Fe3+ to Fe2+, at the time of sintering, even if Fe2+ contained in ferrous phosphate octahydrate as the starting materials for synthesis is oxidized to Fe~~ by oxygen in atmosphere or due to sintering. Therefore, even if Fe3+ is left in the starting materials for synthesis, impurities may be prevented from being generated to assure single-phase synthesis of the LiFeP04 carbon composite material:
Moreover, the carbon material acts as an antioxidant for preventing oxidation of Fe2+
contained - in the starting materials for synthesis to Fe3+. That is, the carbon material prevents oxidation to Fe~+ of Fe2+ by oxygen present in atmosphere and in a sintering oven prior to or during sintering.

s That is, tl7e CaI'b0I1 117atel'lal acts not only as an electrification agent for improving the electronic conductivity of the cathode active material but also as a reducing agent. and as an antioxidant. Meanwhile, since this carbon material is a component of the LiFePO~, carbon composite material, there is no necessity of removing the carbon material following synthesis of the LiFePOa carbon composite material. The result is the improved efficiency in the preparation of the LiFePO~
carbon composite material.
It is noted that the carbon content per unit weight of the LiFePO~, carbon composite material be not less than 3 wt%. By setting the carbon content per unit weight of the LiFeP04 carbon composite material to not less than 3 wt%, it is possible to utilize the capacity and cyclic characteristics iWerent in LiFeP04 to its fullest extent:
In the milling process, the mixture resulting from the mixing process is subjected to.milling in which pulverization and mixing occur simultaneously:
By the milling herein is meant the powerful comminuting and nnixing by a ball mill.
A.s the ball mill, a planetary ball mill, a shaker ball mill or a mechano-fusion may.selectively be employed.
By milling the mixture from the mixing process, the starting materials for synthesis and the carbon material can be mixed homogeneously. Moreover, if the starting materials for synthesis is comminuted by milling, the specific surface area of the starting materials for synthesis can be increased, thereby increasing the contact points of the starting materials for synthesis to accelerate the synthesis reaction in the subsequent sintering process.
It is desirable that, by milling the mixture containing the starting materials for synthesis, the particle size distribution of the particle size not less than 3 ym be not larger than 22% in teens of the volumetric intelnation frequency. kith the particle size distribution of the starting materials for synthesis in the above range, the starting materials for synthesis has a surface area sufficient to produce surface activity for carrying out the synthesis reaction. Thus, even if the. sintering temperature is of a low value of e.g., 600°C which is Lower than the melting point of the starting materials for synthesis, the reaction efficiency is optimum, thus realizing the single-phase synthesis of the LiFePO~ carbon composite material satisfactorily.
Moreover, the milling is desirably executed so that the powder density of the LiFeP04 carbon coyposite material will be 2.2 g/cm3 or higher. By comminuting the starting materials for synthesis to give the above defined powder density; the specific surface area of LiFeP04 and hence the contact area between LiFeP04 and the carbon material can be increased to improve the electronic conductivity of the cathode active material.
Thus, by milling the mixture containing the starting material for synthesis, such a cathode active material can be produced which will give a high capacity non-aqueous electrolyte cell l .
In the sintering step; the mixture obtained on compaction in the compression l8 s~ I.

step is sintered. By sintering the mixture, lithium phosphate may be reacted with fer-ous phosphate octahydrate to synthesize LiFePO~, The synthesis reaction of LiFePOa may be represented by the following reaction formula (2):
Li3P0~, + Fe3(P04)2 wH20 -~ 3 LiFePO~ + nHzO
...(2) where n denotes the number of hydrates and is equal to 0 for an anhydride. In the chemical formula (2), Li3P0~ is reacted with Fe~(POa)z or its hydrate Fe3(PO~)Z wH20 where n denotes the number of hydrates.
As may be seen from the chemical formula (2), no by-product is yielded if Fe3(PO~,)2 is used as a starting materials for synthesis. On the other hand, if Fe3(PO~)2 nH20 is used, water, which is non-toxic, is by-produced..
Heretofore, lithium carbonate, arrunonium dihydrogen phosphate and ferrous acetate II; as syntheses materials, are mixed at a pre-set raltio and sil~tered.to synthesize LiFeP04 by the reaction shown by the chemical formula {3):
LiZC03 + 2Fe(CH3C00)2 + 2NH4H2P04 2LiFeP04 + C02 + H20 + 2NH3 + 4CH3COOH ' .-As may be seen from the reaction fornula (3), toxic by-products, such as ammonia or acetic acid, are generated on sintering:with the conventional synthesis method for LiFePO~, therefore, a large-scale equipment, such as gas collector, is a~

required for processing these toxic by-products, thus raising the cost. In addition, the yield of LiFePOa is lowered because these by-products are generated in large quantities.
In the present non-aqueous electrolyte cell l, in wl~~ich Li3P0~, Fe3(PO~)2 or-its hydrate Fe3(PO~)2wH20, where n denotes the number of hydrates, is used as the starting material for synthesis, the targeted LiFePO~ .can be produced without generating toxic by-products. In other words, safety in sintering may be appreciably improved as compared to.the conventional manufacturing method. Moreover, while a large-scale processing equipment is heretofore required for processing toxic by-products, the manufacturing method of the present invention yields only water, which is innoxious, as a by-product, thus appreciably simplifying the processing step to allow to reduce size of the processing equipment. The result is that the production cost can be appreciably lower than if ammonia etc which has to be processed is by-produced in the conventional system. Moreover, since the by-product .is yielded only in minor quantities, the yield of LiFePO~ may be improved significantly.
Although the sintering temperature in sintering the mixture may be 400 to 900°C by the above synthesis method, it is preferably 600°C or thereabouts in consideration of the cell performance. If the sintering temperature is less than 400°C, neither the chemical reaction nor crystallization proceeds sufficiently such that the phase of impurities such as Li~PO~ of the starting materials for synthesis may persist and hence the homogeneous LiFePOq may not be produced: If conversely the sintering temperature exceeds 900°C, crystallization proceeds excessively so that the LiFePO~
pauticles are coarse in size to decrease the contact area between LiFePO~ and the carbon material to render it impossible to achieve sufficient discharging capacity.
During sintering., Fe in the LiFePO~, carbon composite material synthesized is in the bivalent state. So, in the temperature of the order of 600°C as the synthesis temperature, Fe in the LiFePO~ carbon composite material is promptly oxidized to Fe~i-by oxygen in the sintering atmosphere in accordance with the chemical formula shown by the chemical formula (4) so that impurities such as trivalent Fe compounds are produced to obstruct the single-phase synthesis of the LiFePO~ carbon composite material:
6LiFePO~ + 3/202 -~2Li3Fe2(PO~)3 + Fe203 ...(q.) Then, inert gases, such as nitrogen or argon, or reducing gases, such as hydrogen or carbon monoxide, are used as the sintering atmosphere, while the.oxygen concentration in the sintering atmosphere is prescribed to a range within which Fe in the LiFePO~, carbon composite material is not oxidized, that is to not larger than 1012 ppm (volume). By setting the.oxygen concentration in the sintering atmosphere to 1012 ppm (volume) or less, it is possible to prevent Fe from being oxidized even at the synthesis temperature of 600°C or thereabouts to achieve the single-phase synthesis of the LiFeP04 carbon composite material.
If the oxygen concentration in the sintering atmosphere is 1012 ppm in volume or higher, the amou~~t of oxygen in the sintering atmosphere is excessive, such that Fe in the LiFePO~ carbon composite material is oxidized to Fe~~~ to generate impurities to obstuuct the single-phase synthesis of the LiFeP04 carbon composite material.
As for takeout of the sintered LiFePO~ carbon composite material, the takeout temperature ofthe sintered LiFePOa carbon composite material, that is the temperature of the LiFeP04 carbon composite material exposed to atmosphere, is desirably 305°C
or lower. On the other hand, the takeout temperature of the sintered LiFeP04 carbon composite material .is more desirably 204°C or lower. By setting the takeout temperature of the LiFePOa carbon composite material to 305°C or lower, Fe in the sintered LiFePO~ carbon composite material is oxidized by oxygen in atmosphere to prevent impurities fi-om being produced.
If the sintered LiFeP04 carbon composite material is taken out in an insufficiently cooled state, Fe in the LiFeP04 carbon composite material is oxidized by oxygen in atmosphere; such that impurities tend to be produced: However; if the LiFeP04 carbon composite material is cooled to too low a temperature, the operating efficiency tends to be lowered.
Thus, by setting the takeout temperature of the sintered LiFeP04 ~ carbon composite. material to 305°C or lower, it is possible to prevent.Fe in the siiztered LiFeP04 carbon composite material from being oxidized by oxygen in atmosphere and hence to prevent impurities from being generated to maintain the operation efficiency as well as to synthesize the LiFeP04 carbon composite material having desirable cell characteristics with high efficiency.
Meanwhile, the cooling of the as-sintered LiFePOa carbon composite material is carried out in a sintering furnace. The cooling method used may be spontaneous cooling or by forced cooling. However, if a shorter cooling time, that is~ a higher operating efficiency, is envisaged, forced cooling is desirable. In case the forced cooling is used, it is sufficient if a gas mixture of oxygen and inert gases;
oz- only the inert gases, are supplied il~to the sintering fun pace so that the oxygen concentration in the sintering furnace will be not higher than the aforementioned oxygen concentration, that is, 1012 ppm (volume) or less.
In the foregoing, the carbon material is added prior to the milling step.
Alternatively, the carbon material may also be added after the milling step or after the sintering step.
However, if the carbon material is added after the sintering step, the reducing effect or the oxidation preventative effect during sintering cannot be obtained; such that the addition is useful only for improving the electrical conductivity.
Thus, in case .
the carbon material is added after the sintering step, it becomes necessary to prevent Fe3+ fi-om being left over by other suitable measures:
It is noted that, if the carbon material is added after the sintering step, the product synthesized on sintering is not the LiFeP04 carbon composite material but is LiFeP04.. So, milling is again applied after the carbon material is added to LiFeP04 synthesized on sintering. By this second milling, the carbon material added is con~minuted and hence is more liable to become attached to the surface of LiFePO~.
Mol-eover, by this second milling, LiFePO~ and the carbon material are mixed sufficiently to pei7nlt the C01n11111111ted Cal'b017 117ateI'lal to be attached unlfonnly to the surface of LiFePO~, thus, even in case the carbon material is added after sintering, it is possible to obtain a product similar to one obtained on addition of a carbon material prior to milling, that is the LiFePOa carbon composite material, as well as to achieve ..
the favorable effect similar to that described above. .
A non-aqueous electrolyte cell l, employing the LiFePO~, carbon composite material produced as described above, as the cathode active material, is prepared e.g., as follows.
As the cathode material 2, the LiFePO~, carbon composite. material as the cathode active material and a binder are dispersed in a solvent~to prepare a sluhried cathode mixture. The so produced cathode mixture is evenly coated on the cathode current collector? and dried in situ to form the layer of the cathode active.lnaterial 8 to prepare the cathode.material 2. As the binder for. the cathode mixture, any suitable known binder may be used. Alternatively, any suitable known binder may be added to the aforementioned cathode mixture. . .
In the present embodiment, the LiFeP04 carbon composite material is used as the: cathode active material. However, the present invention is not limited thereto. In the present. invention, LiFeP04 by itself may be used as the cathode active material, or. a compound represented by the general fol-lnula Li,;Fe~_~,MyPO4 of the olivinic structure and which is different from LiFePO~, , where M is at least one selected from the gn'oup consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, AI, Ga, Mg, B and Nb, with 0.05 _< x <_ 1.2 and 0 <_ y _< 0.8, may be used as the cathode active material either singly or Ill COInblllati011 wlth Otl7eI' materials. These compounds may be enumerated by, for example, LiFeo.2Mno.hPO~, LiFeo.2Cro,8POa, LiFeo.2Co~,.BPOa; LiFeo.2Cuo,8P0~,, LiFeo,2Nio.APO~, LiFeo_~sVo,~sPO~, LiFeo.ZSMoo.~sPO~, LiFeo.25Tio_~SPOa, LiFeo,3Zno.7P0~;, LiFeo,3Alo.~POa, LiFeo,3Gao.~PO~, LiFeo.2sMgo.~sPOa, LiFeo,2sBo.~5P0~, and LiFeo.zsNbo.~sP04.
In preparing the anode material 3, the anode active material and the cathode active material are first dispersed in a solvent to form a slul'ried anode mixture. The so produced anode mixture is evenly coated on the anode current collector and dried in situ to form a layer of the anode active material to prepare the anode material 3.-As the binder for the anode mixture, any suitable known binder may be used.
Alternatively; any suitable known binder may be added.to the anode mixture.
The width-wise dimension ofthe anode material3 is 'selected to.be larger than that of the cathode material 2. Preferably, the anode material 3 is formed to be 0.05 to 2.0 rlnn broader in width than the cathode material 2.
The cathode material 2 and the anode material 3, thus produced; are layered together, via separator 4, and coiled together a plural number of times, to form the cell device S so that the ratio of the ilv~er diameter d to the outer diameter D, that is d/D, will be such that 0.05 < d/D < 0.5..

The non-aqueous electrolyte solution is prepared by dissolving an electrolyte salt in a non-aqueous solvent.
The cell device 5 is housed via insulating plate 13 in a cell can 6 into which the non-aqueous electrolyte solution then is charged. A lid 15 and a safety valve device 16 are caulked together to the cell can 6 via gasket 14 to complete tl~e non-aqueous electrolyte cell 1.
Examples The present invention is now explained with reference to. specified Examples based on experimental results.
First, sample cells of the Examples and Comparative Examples, with various values of the ratio of the inner diameter d to the outer diameter D of the cell device;
were prepared to evaluate the discharge capacity and the capacity upkeep ratio.
Example 1 First; a lithium phosphorus oxide (LiFePO~), as a cathode active material, was prepared under the following conditions:
Lithium phosphate and iron oxide II octahydrate were mixed so that the lithium to iron element ratio is l:l, and acetylene black powders were added in an amount corresponding to 10% of the entire material for sintering, in order to yield a sample mixture. This sample mixture was charged into an alumiina vessel and milled with a planetary ball mill under. the conditions of the sample to alumina ball weight ratio of 50%, rotational velocity of250 rpm and the driving time of 10 hours. The milled mass then was sintered at 600°C for five hours in an electrical oven in a ceramic cmcible to yield LiFePOa.
Using the so obtained LiFePO~, as cathode active material, LiFePO~. and polyvinylidene fluoride as fluorine resin powders as a binder were mixed at a weight ratio of 95:5 to yield a cathode mixture, which was then dispersed in N-methyl pyrolidone as a solvent to give a slurried cathode mixture. This slum-ied cathode mixture was coated evenly on both surfaces of a strip-shaped altnninum foil, which proves a cathode current collector, 20 pm in thickness and 33.5 nvn in. width, and was dried in situ. The resulting dried product was compression molded in a roll press to yield a strip-shaped cathode material. In this cathode material, the cathode active material is coated on both sides of the cathode cun-ent collector to approximately the same film thickness, with the sum of the elm thicknesses on both sides being 200 yn.
Pulverized pitch coke, used as an anode active material, and polyvinylidene fluoride; as a binder, were mixed together at a weight ratio ~of. 90:10, to prepare an anode mixture, which then was dispersed in N-methyl pyrrolidone as a solvent to form a slurried anode mixture. This slurried anode mixture was coated evenly on both sides of a strip-shaped . copper foil, which proves an anode current collector, l 0 pm in thickness and 35.0 mm in width, and was dried in situ. The resulting dried product was compression molded, as in the case of the cathode mixture, in a roll press, to prepare a strip-shaped anode material. Meanwhile, in this anode material, the anode active material is formed to approximately the same film thickness on both sides of the anode active material, with the sum of the film thicknesses on both sides being 200 ym.
The anode material and the cathode material, thus prepared, are layered, via a pair of separators of micro-porous polypropylene, 25 ~m in thicla~ess, in the order of the anode mixture, separator, cathode material and the separator, and wound spirally a plural n wnber of times to form a coil device. The cell device was prepared so that its inner diameter d and its outer diameter D will be 2.0 mm. and 13.2 mm, respectively, with the ratio ofthe inner diameter d to the outer diameter D or d/D being 0.152.
After mounting insulating plates on the upper and lower surfaces of the cell device, prepared as described above, the cell device was housed in a cell can.
A
cathode lead, mounted on the anode mixture, was derived from the anode material and welded to the cell can. An anode lead, mounted on the anode material, was also derived from the anode material and welded to the cell can. An electrolyte solution obtained on mixing propylene carbonate, into which lithium phosphate hexafluoride was dissolved at-a rate of 1 moll, with 1,2-dimethoxyethane , was charged into .the cell can until the cathode and anode materials and the separator were wetted sufficiently.
The cell can and a lid were caulked together via a gasket and sealed together.
In this manner, a cylindrically-shaped cell with outer and inner diameters of 13.8 mm and 13.3 mm; respectively, and a height of 42 nvn, were prepared.
Example 2 A cylindricaaly-shaped cell was prepared in the same way as in Example 1 except setting the inner diameter d to 4.0 mm and the ratio of the inner diameter d to the outer diameter D, or d/D, to 0.303.
Comparative Example 1 A cylindrically-shaped cell was prepared in the same way as in Example 1 except setting the inner diameter d to 0.6 mm and the ratio of the inner diameter d to the outer diameter D, or d/D, to 0.046.
Comparative Example 2 A cylindrically-shaped cell was prepared in the same way as in Example 1 except setting the inner diameter d to 7.0 mm and the ratio of the imier diameter d to the outer diameter D, or d/D, to 0.530.
These four cells of the Examples 1 and 2 and the Comparative Examples. l and 2 were tested as to charging/discharging cycles of charging for three hours with the current of 190 mA up to an upper limit voltage of 4.2'J and discharging with the current of 150 mA up to the tenniilating voltage of 2~.SV, aald the discharge capacity at the tenth cycle where the charging/discharging :capacity was stabilized was measured for each cell. On the other hand, this test on charging/discharging cycles was carried out 100 cycles and the ratio of the discharge capacity after 100 cycles to the discharge. capacity after ten cycles was calculated for eaclr cell as a capacity upkeep.
ratio. The results are also shown in Table 1.

Table 1 Ex.l Ex.2 Comp. Ex.l Comp. Ex.2 imer diameter d (mm) 2.0 4.0 0.6 7.0 outer diameter D (mm) 13.2 13.2 13.2 13.2 d/D 0.152 0.303 0.046 0.530 weight of cathode material3.7 2.5 4.4 1.1 (g) weight of anode material2.5 1.7 3.0 0.'8 (g) discharge capacity (mAh)350 307 231 143 capacity upkeep ratio 92.6 94.3 72.3 90.2 (%) If, in a non-aqueous electrolyte cell, practically u:>eful cell characteristics are considered, it is desirable that the discharge capacity after ten cycles be not less than 200 mAh and that the capacity upkeep ratio after 100 cycles be not less than.80%. In this consideration, the discharge capacity and the capacity upkeep ratio were evaluated.
In Table l, in the cell ofthe Comparative Example :l where the ratio ofthe inner diameter to the outer diameter of the cell or d/D is not less than 0.5, the capacity upkeep ratio is not less than 90%. However, since the amount of the cathode active material and the anode active material introduced are smaller than those of the other sample cells, the discharge capacity is extremely small and not larger than 200mAh.
In the sample cell of Comparative Example 1 where the ratio of the inner diameter to the outer diameter of the cell or d/D is not larger than 0.05, the discharge capacity is not less than 200mAh, however, the electro-chemical properties of the active material are deteriorated due to volumetric changes of the cell device at the time of charging/discharging, oz' the active material is peeled off or detached, with the result that the capacity upkeep ratio is lower than that of the other sample cells and is not larger than 80%.
Conversely, with the sample cells of Examples 1 and 2 where the ratio of the imler diameter to the outer diameter of the cell or d/D i s not less than 0.05 and less than 0:5', the discharge capacity is not less than 300mAh, while the capacity upkeep ratio after 100 cycles exceeded 90%. These values are sufficient in view of characteristics ofpractically usable cells.
Several cells were prepared as the difference between the width of the anode material and that ofthe cathode material was changed, and evaluation was made ofthe discharge capacity and the capacity upkeep ratio by the above-described method. The results are shown in Table 2.
Example 3 A cylindrically-shaped cell was prepared in the same way as in Example 1 except using a cathode material having a width of 31 mun.
Example 4 A cylindrically-shaped cell was prepared in the same way as in Example 1 except using a cathode material having a width of 34 mm.
Example 5 A cylindrically-shaped cell was prepared in the same way as in Example 1 except using a cathode material having a width of 34.9 mm.
Comparative Example 3 A cylindrically-shaped cell was prepared in the same way as in Example 1 except using a cathode material having a width of 35 mm.
Comparative Example 4 A cylindrically-shaped cell was prepared in the same way as in Example 1 except using a cathode material having a width of 35 mu nand an anode material having a width of 33 imn.

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If, in a non-adueous electrolyte cell, practically usefiil cell characteristics are considered, it is desirable that the discharge capacity after ten cycles be not less than 200mAh and that the capacity upkeep ratio after 100 cycles be not less than 80%. In thi s consideration, the discharge capacity and the capacity upkeep ratio were evaluated.
As may be seen fi-om Table 2, the discharge capacity of the cells of the Comparative Examples 3 and 4, where the width of the anode plate is the same as or smaller than that ofthe cathode plate, the discharge capacity is not less than200 mAh, however, these cells are lower in discharge capacity than the cells of the Examples.
Moreover, with the cells of the Comparative Examples 3 and 4, the capacity uplceep ratio is not larger than 80%. Conversely, the cells of the lJxamples 3 to 5, where the width of the anode plate is larger than that of the cathode plate, the discharge capacity and the capacity upkeep ratio are not less than 300mAh and not less than 80%, respectively, which are sufficient values of the discharge capacity in view of the practically useful cell characteristics. .
The above six cells are disintegrated in the charged state. It was found that, with the cells ofthe Comparative Examples 3 and 4 where the capacity upkeep ratio is not larger than 80%, metal lithium was precipitated especially in the vicinity of both axial ends of the anode. Conversely, with the cells of the Examples 1 and 3 to 5 where the width of the anode material is larger than the width of the cathode material, no metal lithium was seen to be precipitated on the anode. That is, by setting the width of the anode plate so as to be larger than the width of the cathode plate, it is possible to suppress precipitation of metal lithium which might interfere with the charging/discharging reaction.
The above results indicate that, in the non-adueous electrolyte cell, the discharge capacity as well as the capacity upkeep ratio can be improved to maintain the Chal'g111g/dlSChai'glllg cycle life by forming the anode material so as to be broader in width than the cathode material. In the case of a cell in which one side of the anode material is broaderin width by 2..0 lnln than the cathode material; a sufficient discharge capacity may be maintained, however, the proportion in the cell device.of the wasteful anode active material not contributing to the cell reaction i;s increased.
This, the anode material is preferably broader in a range from 0.05 lnln to 2.0 lnln with respect to the cathode material, in which case the cell may be of a large discharge capacity and a high capacity upkeep ratio.
Cells of Examples 6 to 19, shown below, were fabricated, and evaluation was made of the discharge capacity and the capacity upkeep ratio thereof by the above-described methods.
Example 6 A cell vvas prepared under the saane condition as that for the cell of Example except using LiFeo.2Mn o.HP04 as the cathode active material in place of the LiFeP04.
Example.?
A cell was prepared under the same condition as that for the cell of Example 1 except using LiFe~.2Cro.AP04 as the cathode active material in place of the LiFePO~

Example 8 A cell was prepared under the same condition as that for the cell of Example 1 except using LiFeo.ZCoo,xPO~ as the cathode active material in place of the LiFePO~.
Example 9 A cell was prepared under the same condition as that for the cell of Example 1 except. using LiFeo.2Cuo,~PO~, as the cathode active material in place. of the LiFePO~.
Example 10 A cell was prepared under the same condition as that for the cell of Example 1 except using LiFeo.2Nio.8P0~ as the cathode active material in place of the LiFePO~.
Example 11 A cell was prepared under the same condition as that for the cell of Example 1 except using LiFeo,zsVo.~sPO~ as the cathode active material in place of the LiFePO~.
Exaanple 12 A cell was prepared under the same condition as that for the cell of Example 1 except using LiFeo.25Moo.~5P04 as the cathode active material in place of the LiFePOa.
Example 13 A Gell was prepared under the same condition as tl-~at .for the cell of Example 1 except using LiFeo_25Tio.~5P0~ as the cathode active material in place of the LiFePO~.
Example 14 A cell was prepared under the same condition as that for the cell of Example 1 except using LiFeo.3Zno.~P04 as the cathode active material in place of the LiFePO~.

Example 15 A cell was prepared under the same condition as That for the cell of Example 1 except using LiFeo.3Alo.~PO~ as the cathode active material in place of the LiFePO~,.
Example 16 A cell was prepared under the same condition as that for the cell of Example 1 except using LiFeo.3Gao,~PO~ as the cathode active material in place of the LiFePOa.
Example 17 A cell was prepared under the same condition as that for the cell of Example 1 except using LiFeo,zsMgo.~sPOa as the cathode active material in place of the LiFePO~.
Example 18 A cell was prepared under the same condition as that for the cell of Example 1 .
except using LiFeo.25Bo.~sPOa as the cathode active material in place of the LiFeP04.
Example 1.9 A cell was prepared under the same condition as th<~t for the cell of Example except using LiFeo.25Nbo..,5P04 as the cathode active material in place of the LiFeP04.
Ofthe cells ofExamples 6 to 19, evaluation was made ofthe discharge capacity and the capacity wpkeep ratio. 1t was found that the favorable results similar to those .
for the Example 1 could be produced.

Claims

WHAT IS CLAIMED IS:

1. A non-aqueous electrolyte cell comprising:
a cell device including a strip-shaped cathode material and a strip-shaped anode material, which are layered via a separator and coiled a plural number of times;
a non-aqueous electrolyte solution; and a cell can for accommodating the cell device and the non-aqueous electrolyte solution, wherein said cathode material employs a cathode active material containing a compound of an olivinic structure represented by a general formula Li x Fe1-y M y PO4, where M is at least one selected from a group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05 <= x <= 1.2 and 0 <= y <=
0.8, which compound is used either singly or in combination with other materials and wherein a ratio of an inner diameter d to an outer diameter D of said cell device is 0.05 <d/D< 0.5.

2. The non-aqueous electrolyte cell according to claim 1 wherein said cathode active material is a composite material composed of LiFePO4 and a carbon material.

3. The non-aqueous electrolyte cell according to claim 1 wherein said cathode active material is LiFe0.2Mn0.8PO4, LiFe0.2Cr0.8PO4, LiFe0.2Co0.8PO4, LiFe0.2Cu0.8PO4, LiFe0.2Ni0.8PO4, LiFe0.25V0.75PO4, LiFe0.25Mo0.75PO4, LiFe0.25Ti0.75PO4, LiFe0.3Zn0.7PO4, LiFe0.3Al0.7PO4, LiFe0.3Ga0.7PO4, LiFe0.25Mg0.75PO4, LiFe0.25B0.75PO4 or LiFe0.25Nb0.75PO4.

4. The non-aqueous electrolyte cell according to claim 2 wherein said carbon material is an amorphous carbon material such as aceylene black.

5. The non-aqueous electrolyte cell according to claim 1 wherein said anode active material of said anode material is a material capable of doping/dedoping lithium.

6. The non-aqueous electrolyte cell according to claims 1 wherein the anode active material of. said anode material is metal lithium, lithium alloys, lithium-doped electrically conductive high molecular materials, or a layered compound of carbon materials or metal oxides.

7. The non-aqueous electrolyte cell according to claim 1 wherein the anode material is broader in width than the cathode material.

8. The non-aqueous electrolyte cell according to claim 1 wherein the anode material is broader in width by 0.05 to 2.0 mm on each side than the cathode material.