WO2003018687A2

WO2003018687A2 - Thermosetting polyvinyl alcohol binder resin composition, slurry of electrode mix, electrode, non-aqueous electrolysis solution-containing secondary battery and use of thermosetting polyvinyl alcohol binder resin as electrode material

Info

Publication number: WO2003018687A2
Application number: PCT/JP2002/008808
Authority: WO
Inventors: Kenji Suzuki; Kiyotaka Mashita; Hiroyuki Sonobe; Satoshi Nakazawa; Eisuke Haba; Toshihiko Itou; Shin Nishimura; Tsuneo Narusawa
Original assignee: Hitachi Chemical Co., Ltd.
Priority date: 2001-08-30
Filing date: 2002-08-30
Publication date: 2003-03-06
Also published as: AU2002328087A1; WO2003018687A3

Abstract

The invention provides a thermosetting binder resin composition comprising: (A) a thermosetting polyvinyl alcoholic binder resin, (B) an acrylic resin plasticizer and (C) a solvent; a thermosetting binder resin composition comprising a thermosetting polyvinyl alcoholic binder resin having thermosetting units represented by the following general formula (III) and a solvent; a slurry of an electrode mix containing the binder resin composition; and an electrode and non-aqueous electrolysis solution-containing secondary battery using the same: (III) wherein one of R3 and R4 represents a hydrogen atom and the other represents an alkenyl group.

Description

DESCRIPTION

Thermosetting Polyvinyl Alcoholic Binder Resin Composition, Slurry of Electrode Mix, Electrode, Non-Aqueous Electrolysis Solution-Containing Secondary battery and Thermosetting Polyvinyl Alcoholic Binder Resin as Electrode Material

Technical Field

The present invention relates to a thermosetting polyvinyl alcoholic binder resin composition, a slurry of an electrode mix, an electrode, a non- aqueous electrolysis solution-containing secondary battery and a thermosetting polyvinyl alcoholic binder resin as an electrode material.

Background Art Electronic machinery and tools have gradually been miniaturized and have been made portable and accordingly, there has been desired for the development of a secondary battery, as a power supply source therefor, having a high energy density and an extended service life.

Recently, there has been developed a non-aqueous electrolysis solution-containing lithium ion secondary battery (hereunder referred to as "a hthium secondary battery"), which permits the considerable improvement in the energy density and such a lithium secondary battery has rapidly been popularized.

This hthium secondary battery principally uses a lithium-containing metal compound oxide as a positive electrode-active material and a carbonaceous material having a multi-layer structure, as a negative electrode- active material, which permits the insertion of Hthium ions into interstices between layers (the formation of a Hthium-containing intercalation compound) and the release of Hthium ions. Such a positive or negative electrode plate has been produced by kneading the corresponding active material and a binder resin composition (comprising a binder resin and a solvent such as N-methyl-2-pyrroHdone or water) to thus form a slurry of an electrode mix, applying the resulting slurry onto the both sides of a metal foil serving as a current collector, removing the solvent through the drying of the apphed slurry layer to thus form a layer of the electrode mix and then subjecting the resulting product to compression molding using a roller press machine.

Polyvinyhdene fluoride (hereunder referred to as "PVDF") has widely been used as such a binder resin for the both positive and negative electrodes. However, the adherence at the boundary between the current coUector and the layer of the electrode mix is insufficient when PVDF is used as a binder resin and therefore, problems arises, for instance, (1) the layer of the electrode mix is partially or completely peeled off and/or dropped out from the current coUector in the process for cutting the positive and negative electrode plates or in the process for winding the electrode plates through a separator into a spiral form and (2) the layer of the electrode mix is partially or completely peeled off and/or dropped out from the current collector because of the expansion and shrinkage of the carbonaceous material as a negative electrode-active material associated with the charge-discharge cycle of the resulting Hthium secondary battery and this becomes a cause of the reduction of the energy capacity in the charge-discharge cycle of the Hthium secondary battery.

As an example of means for solving these problems, Japanese Un- Examined Patent PubHcation (hereunder referred to as "J.P. KOKAI") No. Hei 6-172452 discloses the use of a vinyHdene fluoride copolymer prepared by copolymerizing vinyHdene fluoride as a principal component with a small amount of an unsaturated dibasic acid monoester. When using such a vinyHdene fluoride copolymer as a binder resin, the adherence at the boundary between the current coUector and the layer of the electrode mix is considerably improved, but this method is attended by various ill effects, for instance, (1) the crystaUinity of the binder resin is reduced, this leads to the reduction of the resistance of the resin to an electrolysis solution (hereunder referred to as "electrolysis solution resistance") injected after the winding of the electrode plates, the electrode plates are in turn Hable to get swoUen, this further results in the incomplete contact between the current coUector and the layer of the electrode mix at the boundary and the contact between the active materials in the layer of the electrode mix, this correspondingly leads to the destroy of the conductive network over the whole electrode plates and the energy capacity of the resulting ceU is thus reduced and (2) the electrode assembly is Hable to cause decomposition accompanied by the release or formation of strongly corrosive hydrogen fluoride under a high voltage condition, this in turn leads to an increase in the internal pressure and the resulting ceU would fail to function. In short, the foregoing problems have never substantially been solved.

Moreover, as a substitute for the fluorine atom-containing system such as PVDF serving as the binder resin, there has been proposed the use of a diene-type synthetic rubber such as styrene-butadiene rubber (hereunder referred to as "SBR") in J.P. KOKAI No. Hei 5-74461. Most of such diene-type synthetic rubber materials such as SBR are exceUent in the electrolysis solution resistance in themselves, but the active material is substantiaUy unstable in the slurry of the electrode mix prepared using the synthetic rubber and the active material is apt to easily undergo precipitation or sedimentation. For this reason, an additive, for instance, a thickening agent such as ceUulose or a surfactant should be incorporated into the slurry. However, this results in the reduction of the energy capacity of the resulting Hthium secondary battery since these additives are dissolved in the electrolysis solution used.

On the other hand, there have also been proposed various binder materials having characteristic properties different from those observed for the foregoing fluorine atom-containing or rubber-type binder resins. For instance, J.P. KOKAI Nos. Hei 9-115506, Hei 11-67215, Hei 11-67216 and Hei 11-250915 disclose binder resins capable of forming hydrogen bonds and mainly comprising polyvinyl alcohol.

However, aU of these polyvinyl alcohol-based binder resins are thermoplastic materials. Accordingly, they are insufficient in the electrolysis solution resistance at a high temperature (50°C) in the proximity to the upper Hmit of the working temperature of the Hthium secondary battery and the resulting Hthium secondary battery has a short service life at a high temperature. Moreover, these resins are crystaUine and hard polymers and they are insufficient in softness and flexibiHty. Therefore, when they are used alone, they suffer from a variety of problems such that they cause cracking, peeHng off and/or dropping out of the layer of the electrode mix during the roUer press-molding or winding process and it is thus difficult to produce any normal Hthium secondary battery.

Disclosure of the Invention

Accordingly, it is an object of the present invention to provide a polyvinyl alcohoHc thermosetting binder resin composition, which is exceUent in the electrolysis solution resistance at a high temperature (50°C) in the proximity to the upper Hmit of the working temperature of the Hthium secondary battery, which can be used in the preparation of a ceU without causing any cracking, peeHng off and or dropping out of a layer of an electrode mix containing the same and which is exceUent in the softness and flexibiHty.

Another object of the present invention is to provide a slurry of an electrode mix at least comprising the foregoing polyvinyl alcohoHc thermosetting binder resin composition and a positive or negative electrode- active material.

AstiU another object of the present invention is to provide an electrode prepared by applying the foregoing slurry of the electrode mix onto a current coUector and then drying the coated slurry.

A further object of the present invention is to provide a non-aqueous electrolysis solution-containing secondary battery, which makes use of the foregoing electrodes, which permits substantial reduction of the energy capacity decrease possibly observed during charge-discharge cycles at 50°C and which thus has a long high temperature service life.

A stiU further object of the present invention is to provide a thermosetting polyvinyl alcohoHc binder resin used as an electrode material for non-aqueous electrode-containing secondary batteries. According to the present invention, there is thus provided a thermosetting polyvinyl alcohoHc binder resin composition, a slurry of an electrode mix, an electrode, a non-aqueous electrolysis solution-containing secondary battery and a thermosetting polyvinyl alcohoHc binder resin used as an electrode material for non-aqueous electrode-containing secondary batteries, as wiU be detailed below.

1. A thermosetting binder resin composition which comprises (A) a thermosetting polyvinyl alcohoHc binder resin, (B) an acryHc resin plasticizer and (C) a solvent. 2. The thermosetting binder resin composition as set forth in the foregoing item 1, wherein the component (A) has thermosetting units represented by the foUowing general formula (I):

wherein R represents a divalent organic group.

3. The thermosetting binder resin composition as set forth in the foregoing item 1, wherein the component (B) is a polymerized product derived from a monomer represented by the foUowing general formula (II) or a derivative thereof: Ri

( II ) CH₂=C-COO-R₂ wherein _: represents a hydrogen atom or a methyl group and R₂ represents a hydrogen atom, a glycidyl group or an alkyl group having 6 to 18 carbon atoms.

4. The thermosetting binder resin composition as set forth in any one of the foregoing items 1 to 3, wherein the component (C) is a nitrogen atom- containing organic solvent or a mixed solvent containing the same. 5. A thermosetting binder resin composition which comprises a thermosetting polyvinyl alcohoHc binder resin having thermosetting units represented by the foUowing general formula (III):

wherein one of R₃ and R₄ represents a hydrogen atom and the other represents an alkenyl group and a solvent.

6. The thermosetting binder resin composition as set forth in the foregoing item 5, wherein the alkenyl group in the thermosetting unit is a dodecenyl group. 7. A thermosetting binder resin composition which comprises a thermosetting binder resin whose solubiHty parameter ranges from 24.5 to

26.5 (MJ/m³)¹'² and a solvent.

8. A slurry of an electrode mix which comprises a thermosetting binder resin composition as set forth in any one of the foregoing items 1 to 7 and a positive or negative electrode-active material.

9. The slurry of an electrode mix as set forth in the foregoing item 8, wherein the positive electrode- active material is a Hthium-containing metal compound oxide capable of reversibly inserting and releasing Hthium ions by the charge-discharge cycle. 10. The slurry of an electrode mix as set forth in the foregoing item 8, wherein the negative electrode-active material is a carbonaceous material capable of reversibly inserting and releasing Hthium ions by the charge- discharge cycle.

11. An electrode prepared by applying a slurry of an electrode mix as set forth in any one of the foregoing items 8 to 10 onto a current coUector and then drying the coated layer of the slurry. 12. A non-aqueous electrolysis solution-containing secondary battery which comprises the electrode as set forth in the foregoing item 11. 13. A non- aqueous electrolysis solution-containing secondary battery which comprises electrodes and an electrolysis solution containing a chain organic solvent, wherein the electrode is one prepared by applying a slurry of an electrode mix, which comprises a thermosetting binder resin composition and a positive or negative electrode-active material, onto a current coUector and then drying the coated slurry and wherein the difference between the solubiHty parameter (SP value) of the thermosetting binder resin and the SP value of the chain organic solvent is not less than 3 (MJ/m³)^1/2. 14. The non-aqueous electrolysis solution-containing secondary battery as set forth in the foregoing item 13, wherein the degree of swelling, as determined at 50°C, of the thermosetting binder resin with respect to the electrolysis solution is not smaUer than that as determined at 25°C and the former is less than 10%. 15. The non-aqueous electrolysis solution-containing secondary battery as set forth in the foregoing item 13, wherein the thermosetting binder resin has a winding abiHty.

16. The non-aqueous electrolysis solution-containing secondary battery as set forth in the foregoing item 13, wherein the thermosetting binder resin is a thermosetting polyvinyl alcohoHc binder resin having thermosetting units represented by the foUowing general formula (III):

wherein one of R₃ and R₄ represents a hydrogen atom and the other represents an alkenyl group.

17. The non-aqueous electrolysis solution-containing secondary battery as set forth in the foregoing item 16, wherein the alkenyl group in the thermosetting unit is a dodecenyl group.

18. The non-aqueous electrolysis solution-containing secondary battery as set forth in the foregoing item 13, wherein the thermosetting binder resin composition comprises (A) a thermosetting polyvinyl alcohoHc binder resin, (B) an acryHc resin plasticizer and (C) a solvent.

19. A thermosetting polyvinyl alcohoHc binder resin used as an electrode material for non-aqueous electrolysis solution-containing secondary batteries, which comprises thermosetting units represented by the foUowing general formula (III):

20. The thermosetting polyvinyl alcohoHc binder resin as set forth in the foregoing item 19, wherein the alkenyl group present in the thermosetting unit is a dodecenyl group. Best Mode for Carrying Out the Invention

In the thermosetting binder resin composition of the present invention, the component (A) or the thermosetting polyvinyl alcohoHc binder resin can be prepared by incorporating thermosetting units into a polyvinyl alcohoHc resin. Examples thereof include polyvinyl alcohoHc resins having introduced therein thermosetting units such as carboxyl or epoxy groups. Among these resins, polyvinyl alcohoHc resins carrying carboxyl groups introduced therein are preferably used herein since they can satisfy both requirements for thermosetting property and storage stabihty at the same time, with polyvinyl alcohoHc resins carrying thermosetting units represented by the foUowing general formula ( ) being more preferably used because of, for instance, the easiness of the introduction of carboxyl groups into the same:

wherein R represents a divalent organic group. These components (A) are preferably used alone or in any combination of at least two of them.

The thermosetting units represented by Formula (I) can in general be introduced into polyvinyl alcohoHc resins through a reaction of polyvinyl alcohoHc resins with a cychc acid anhydride. In this respect, the use of an alkenyl succinic acid anhydride as such a cycHc acid anhydride permits the preparation of the thermosetting polyvinyl alcohoHc binder resin having thermosetting units represented by Formula (III). The term "cycHc acid anhydride" used herein includes "alkenyl succinic acid anhydride" as weU, unless otherwise specified. The polyvinyl alcohoHc resins are not restricted to specific ones, but preferably used herein from the viewpoint of, for instance, electrolysis solution resistance are those having a degree of saponification (determined according to the method for testing polyvinyl alcohol as specified in JIS K6726) of preferably not less than 85 mole%, more preferably not less than 90 mole%, particularly preferably not less than 95 mole% and most preferably not less than 98 mole%.

Moreover, the average degree of polymerization (determined according to the method for testing polyvinyl alcohol as specified in JIS K6726) of the resin preferably ranges from 500 to 5000, more preferably 1000 to 3000 and particularly preferably 1500 to 2500. This is because if the average degree of polymerization is less than 500, the active material present in the slurry of the electrode mix is Hable to easUy undergo sedimentation and the slurry is thus insufficient in the storage stabihty, while if it exceeds 5000, the resin has such a tendency that the solubiHty thereof in a solvent is reduced and that this makes the handling thereof difficult.

Incidentally, the foregoing polyvinyl alcohoHc resin may be a variety of modified derivatives thereof (for instance, those obtained by partiaUy introducing long chain alkyl groups into side chains thereof). These polyvinyl alcohoHc resins may be used alone or in any combination of at least two of them.

The foregoing cycHc acid anhydride is not restricted to any particular one, but specific examples thereof include tetrahydrophthaHc acid anhydride, methyl tetrahydrophthaHc acid anhydride, trialkyl tetrahydrophthaHc acid anhydride, hexahydrophthaHc acid anhydride, methyl hexahydrophthaHc acid anhydride, nadic acid anhydride, methyl nadic acid anhydride, methyl 2-substituted butenyl tetrahydrophthaHc acid anhydride, itaconic acid anhydride, succinic acid anhydride, citraconic acid anhydride, dodecenyl succinic acid anhydride, maleic acid anhydride, methyl cyclop entadiene- maleic acid anhydride adduct, alkylated endoalkylene tetrahydrophthaHc acid anhydride, phthahc acid anhydride, chlorendic acid anhydride, tetrachlorophthaHc acid anhydride, tetrabromophthaHc acid anhydride, tricarbaUyHc acid anhydride, maleic acid anhydride-Hnolenic acid adduct, maleic acid anhydride-sorbic acid adduct and trimeUitic acid anhydride. Among these, preferred is succinic acid anhydride having low steric hindrance, from the viewpoint of, for instance, reactivity with alcohoHc hydroxyl groups present in the polyvinyl alcohoHc resins and the thermosetting property of the resulting component (A). These cycHc acid anhydrides are used alone or in any combination of at least two of them.

The alkenyl succinic acid anhydride used for preparing the thermosetting polyvinyl alcohoHc binder resins carrying thermosetting units represented by the general formula (III) is not restricted to any particular one, but preferably used herein are those carrying dodecenyl group (an alkenyl group having 12 carbon atoms) from the viewpoint of the softness and flexibiHty of the resulting binder resin. These alkenyl succinic acid anhydrides are used alone or in any combination of at least two of them. In addition, cycHc acid anhydrides other than the alkenyl succinic acid anhydride may simultaneously be used for the purpose of controUing, for instance, the thermosetting property and crystaUinity of the resulting binder resin.

In the foregoing reaction, the rate of the cycHc acid anhydride other than the alkenyl succinic acid anhydride relative to the polyvinyl alcohoHc resin preferably ranges from 0.01 to 0.50 equivalent, as expressed in terms of the amount of the acid anhydride groups of the cycHc acid anhydride, more preferably 0.03 to 0.30 equivalent and particularly preferably 0.05 to 0.20 equivalent per one equivalent of alcohoHc hydroxyl groups of the polyvinyl alcohoHc resin. If the amount of the acid anhydride groups of the cycHc acid anhydride is less than 0.01 equivalent, there would be observed such a tendency that the thermosetting property of the resulting component (A) is reduced and that the electrolysis solution resistance thereof is Hkewise reduced. On the other hand, if it exceeds 0.50 equivalent, the crossHnking density achieved after the thermosetting is too high, the resulting thermoset product is accordingly fragUe, the layer of the electrode mix undergoes cracking, peeHng off and dropping out during the ceU-manufacture steps and it is thus quite difficult to prepare a normal ceU. In addition, the resulting product is Hable to include un-reacted cycHc acid anhydride.

The rate of the alkenyl succinic acid anhydride (+ other cycHc acid anhydrides) relative to the polyvinyl alcohoHc resin is not particularly restricted, but the amount of the acid anhydride groups of the alkenyl succinic acid anhydride (+ other cycHc acid anhydrides) preferably ranges from 0.001 to 0.50 equivalent, more preferably 0.005 to 0.30 equivalent and particularly preferably 0.01 to 0.20 equivalent per one equivalent of the alcohoHc hydroxyl groups of the polyvinyl alcohoHc resin. If the amount of the acid anhydride groups of the alkenyl succinic acid anhydride (+ other cycHc acid anhydrides) is less than 0.001 equivalent, there are observed such a tendency that the softness and flexibiHty of the resulting product are Hable to be insufficient, that the thermosetting property thereof is also reduced and that the electrolysis solution resistance thereof is Hkewise reduced. On the other hand, if it exceeds 0.50 equivalent, the crossHnking density achieved after the thermosetting is too high, the resulting thermoset product is accordingly fragUe, the layer of the electrode mix undergoes cracking, peeHng off and dropping out during the ceU-manufacture steps and it is thus quite difficult to prepare a normal ceU. In addition, there is also observed such a tendency that the crystaUinity thereof is reduced, that the electrolysis solution resistance of the product is lowered and that the resulting product contains un-reacted alkenyl succinic acid anhydride (+ other cycHc acid anhydrides).

The foregoing reaction of the polyvinyl alcohoHc resin with the cycHc acid anhydride is preferably carried out in an organic solvent under substantially moisture free conditions. The organic solvent used herein is not particularly restricted and specific examples thereof include amides such as N-methyl-2-pyrroHdone, N,N-dimethylacetamide and N,N- dimethyUbrmamide; ureas such as N,N-dimethyl-ethylene urea, N,N- dimethyl-propylene urea and tetramethyl urea; lactones such as y -butyro- lactone and -caprolactone; carbonates such as propylene carbonate; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate, n-butyl acetate, butyl ceUosolve acetate, butyl carbitol acetate, ethyl ceUosolve acetate and ethyl carbitol acetate; glymes such as diglyme, triglyme and tetraglyme; hydrocarbons such as toluene, xylene and cyclohexane; and sulfones such as sulfolane. Among these, preferred are nitrogen atom-containing organic solvents such as amides and ureas because of, for instance, the high solubiHty in the polyvinyl alcohoHc resins and the high abiHty of accelerating the reaction of the polyvinyl alcohoHc resin with the cycHc acid anhydride. Examples thereof more preferably used include N-methyl-2-pyrroHdone, N,N-dimethylacetamide, N,N-dimethyl-ethylene urea, N,N-dimethyl-propylene urea and tetramethyl urea since they are, for instance, free of any active hydrogen, which is Hable to inhibit the reaction of the polyvinyl alcohoHc resin with the cycHc acid anhydride, with the use of N-methyl-2-pyrroHdone being particularly preferred. These organic solvents may be used alone or in any combination of at least two of them. The amount of the organic solvent to be used preferably ranges from

50 to 10,000 parts by mass, more preferably 200 to 5,000 parts by mass and particularly preferably 300 to 3,000 parts by mass per 100 parts by mass of the sum of the polyvinyl alcohoHc resin and the cycHc acid anhydride. If the amount thereof used is less than 50 parts by mass, their solubiHzing abiHty is insufficient and this in turn makes the reaction system heterogeneous and highly viscous, while if it exceeds 10,000 parts by mass, the reaction is not easUy completed.

The reaction of the polyvinyl alcohoHc resin with the cycHc acid anhydride is carried out at a temperature preferably ranging from 40 to 250°C, more preferably 60 to 200°C and particularly preferably 80 to 150°C. In addition, the reaction time is preferably not less than 10 minutes, more preferably 30 minutes to 10 hours and particularly preferably 1 to 5 hours. If the reaction temperature is lower than 40°C, the reaction does not proceed easily and it is difficult to complete the reaction. On the other hand, if is exceeds 250°C, the reaction system may sometimes undergo gelation because of side reactions and this makes the control of the reaction difficult. If the reaction time is less than 10 minutes, it is difficult to complete the reaction.

In the reaction of the polyvinyl alcohoHc resin with the cycHc acid anhydride, a catalyst may, if necessary, be used. Examples of such catalysts are tertiary amines such as triethylamine, triethylenediamine, N,N- dimethylaniHne, N,N-diethylaniHne, N,N-dimethylbenzylamine, N- methylmorphofine, N-ethylmorphoHne, N,N-dimethyl-piperazine, pyridine, picoHne and l,8-diazabicyclo[5,4,0]undecene-7; imidazoles such as 2- methyhmidazole, 2-ethyHmidazole, 2-ethyl-4-methyHmidazole, 2-methyl-4- methyl-imidazole, l-cyanoethyl-2-methyHmidazole, l-cyanoethyl-2- phenyHmidazole, 2-phenyl-4-methyl-5-hydroxymethyHmidazole, 2-phenyl- 4,5-dihydroxymethyHmidazole and l-azine-2-methyHmidazole; organic tin compounds such as dibutyl-tin cHlaurate and 1,3-diacetoxy tetrabutyl distannoxane; quaternary onium salts such as tetraethyl- ammonium bromide, tetrabutyl-ammonium bromide, benzyltriethyl- ammonium chloride, trioctylmethyl- ammonium chloride, cetyltrimethyl- ammonium bromide, tetrabutyl-ammonium iodide, do decyltrimethyl- ammonium iodide, benzyldimethyl tetradecyl- ammonium acetate, tetraphenyl-phosphonium chloride, triphenylmethyl-phosphonium chloride and tetramethyl- phosphonium bromide; organic phosphorus compounds such as 3-methyl-l- phenyl-2-phosphorene- 1-oxide: alkaH metal salts of organic acids such as sodium benzoate and potassium benzoate; inorganic salts such as zinc chloride, iron chloride, Hthium chloride and Hthium bromide; metal carbonyl compounds such as octacarbonyl dicobalt (II) (cobalt carbonyl); and metal ether compounds such as tetrabutoxy titanium. These catalysts may be used alone or in any combination of at least two of them. The amount of these catalysts used ranges from about 0.01 to 10% by mass on the basis of the soHd contents of the reaction system.

The solubiHty parameter of the thermosetting polyvinyl alcohoHc binder resin of the present invention preferably ranges from 23.5 to 27.5 (MJ/m³)^1/2, and more preferably 24.5 to 26.5 (MJ/m³)^1/2.

The acryHc resin plasticizers as the component (B) used in the present invention are not restricted to specific ones inasmuch as they can impart winding properties to electrodes and examples thereof preferably include polymers of monomers represented by the foUowing general formula (II) or derivatives thereof: CH₂=C(R₁)-COO-R₂ (II) wherein R_: represents a hydrogen atom or a methyl group and R₂ represents a hydrogen atom, a glycidyl group or an alkyl group having 6 to 18 carbon atoms). More preferably used herein are copolymers of monomers represented by Formula (II) wherein R₂ represents an alkyl group having 6 to 18 carbon atoms with monomers represented by Formula (II) wherein R₂ represents a hydrogen atom or a glycidyl group or derivatives of these copolymers and particularly preferably used herein are derivatives of copolymers prepared by copolymerizing monomers represented by Formula (II) wherein R_: represents a hydrogen atom and R₂ represents an alkyl group having 12 carbon atoms (lauryl acrylate) with monomers represented by Formula (II) wherein Rj represents a hydrogen atom and R₂ represents a hydrogen atom (acryHc acid). In this respect, if the carbon atom number of the alkyl group represented by R₂ is less than 6, the electrolysis solution resistance of the resulting resin plasticizer is reduced. On the other hand, if the carbon atom number thereof exceeds 18, the polymeriz abiHty of the monomers is reduced. These components (B) may be used alone or in any combination of at least two of them.

If using the lauryl acrylate-acryHc acid copolymer as a precursor for the component (B), the weight average molecular weight thereof preferably ranges from 1,000 to 1,000,000, more preferably 1,000 to 100,000 and particularly preferably 1,000 to 10,000. This is because if the weight average molecular weight thereof is less than 1,000, the resulting plasticizer may not show its desired function, while if it exceeds 1,000,000, the compatibifity of the plasticizer with the component (A) and the solubiHty thereof in the solvent are reduced and this in turn makes the handHng thereof difficult.

Moreover, the acid value of the copolymer preferably ranges from 10 to 500 KOH mg/g, more preferably 30 to 200 KOH mg/g and particularly preferably 50 to 150 KOH mg/g. If the acid value thereof is less than 10 KOH mg/g, it is difficult to obtain any derivative thereof, whUe if it exceeds 500 KOH mg/g, the resulting derivative has insufficient function as the plasticizer.

When using a derivative of a lauryl acrylate-acryHc acid copolymer as the component (B), examples of such derivatives include reaction products of lauryl acrylate-acryHc acid copolymers with, for instance, polyoxazoHne, polyisocyanate, melamine resin, polycarbodnmide, polyol, polyamine and epoxy resin. Among these derivatives, preferred are reaction products of lauryl acrylate-acryHc acid copolymers with epoxy resins, since they can easUy be prepared, have good compatibiHty with the component (A) and have a high abiHty to impart a high plasticizing abiHty to the thermosetting binder resin composition of the present invention. Examples of the foregoing epoxy resins are bifunctional aromatic glycidyl ethers such as bisphenol A type epoxy resins, tetrabromo-bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins and tetramethyl-biphenyl type epoxy resins; polyfunctional aromatic glycidyl ethers such as phenol-novolak type epoxy resins, cresol-novolak type epoxy resins, dicyclopentadiene-phenol type epoxy resins and tetraphenylol-ethane type epoxy resins; bifunctional aHphatic glycidyl ethers such as polyethylene glycol type epoxy resins, polypropylene glycol type epoxy resins, neopentyl glycol type epoxy resins, dibromo-neopentyl glycol type epoxy resins and hexanediol type epoxy resins; bifunctional aHcycHc glycidyl ethers such as hydrogenated bisphenol A type epoxy resins; polyfunctional aHphatic glycidyl ethers such as trimethylolpropane type epoxy resins, sorbitol type epoxy resins and glycerin type epoxy resins; bifunctional aromatic glycidyl esters such as diglycidyl phthalate; bifunctional aHcycHc glycidyl esters such as diglycidyl esters of tetrahydro-phthaHc acid, diglycidyl esters of hexahydrophthaHc acid, diglycidyl esters of dimeric acids and diglycidyl esters of hydrogenated dimeric acids; bifunctional aromatic glycidyl- amines such as N,N-diglycidyl-aniHne and N,N-diglycidyl-trifl.uoromethyl-aniHne; polyfunctional aromatic glycidyl-amines such as N,N,N',N'-tetraglycidyl-4,4- diaminodiphenyl methane, l,3-bis(N,N-glycidylaminomethyl)cyclohexane and N,N,0-triglycidyl-p-aminophenol; bifunctional aHcycHc epoxy resins such as aHcycHc diepoxyacetal, aHcycHc diepoxy-adipate, aHcycHc diepoxy- carboxylate and vinylcyclohexene dioxide; bifunctional heterocycHc epoxy resins such as diglycidyl hydantoin; polyfunctional heterocycHc epoxy resins such as triglycidyl isocyanurate; bifunctional or polyfunctional siHcon containing epoxy resins such as or ano-polysiloxane type epoxy resins; and epoxy resins prepared by chain-extension reactions of the foregoing bifunctional epoxy resins with aHphatic dicarboxyHc acids (such as succinic acid, glutaric acid, adipic acid, pimeHc acid, azelaic acid, sebacic acid, dodecane-dicarboxyHc acid, eicosane-dicarboxyHc acid, alkylene ether bond- containing dicarboxyHc acids, alkylene carbonate bond-containing dicarboxyHc acids, butadiene bond-containing dicarboxyHc acids, hydrogenated butadiene bond-containing dicarboxyHc acids and dimethyl- sUoxane bond-containing dicarboxyHc acids) and/or aHcycHc dicarboxyHc acids (such as 1,4-cyclohexane dicarboxyHc acids, dimeric acids and hydrogenated dimeric acids).

Among these, preferably used herein are bifunctional epoxy resins from the viewpoint of simultaneous achievement of the plasticity and thermosetting property of the polyvinyl alcohol thermosetting binder resin composition of the present invention. These epoxy resins may be used alone or in any combination of at least two thereof.

In the reaction (derivatization), the amount of the epoxy resins relative to the lauryl acrylate-acryHc acid copolymer preferably ranges from 0.01 to 5 equivalent, more preferably 0.1 to 4 equivalent, particularly preferably 0.3 to 3 equivalent and most preferably 0.5 to 2 equivalent as expressed in terms of the amount of the epoxy groups of the former per one equivalent of the carboxyl groups of the latter. If the quantity of the epoxy groups of the epoxy resin is less than 0.01 equivalent, the compatibiHty thereof with the component (A) is insufficient and the resulting polyvinyl alcohoHc thermosetting binder resin composition of the present invention has insufficient plasticity, while if it exceeds 5 equivalents, the degree of crossHnking thereof becomes too high due to side reactions and therefore, the reaction system is Hable to undergo gelation.

The temperature of the reaction of a lauryl acrylate-acryHc acid copolymer with an epoxy resin preferably ranges from 40 to 250°C, more preferably 60 to 200°C and particularly preferably 80 to 150°C. In addition, the time required for the reaction is preferably not less than 10 minutes, more preferably 30 minutes to 10 hours and particularly preferably 1 to 5 hours. If the reaction temperature is less than 40°C, it is difficult to complete the reaction, while if it exceeds 250 °C , the reaction system sometimes undergoes gelation due to side reactions and this would make the control of the reaction difficult. In addition, if the reaction time is less than 10 minutes, it is difficult to complete the reaction.

The component (C) used in the present invention is not restricted to any particular one, but specific examples thereof are water and alcohols as weU as the foregoing organic solvents Hsted above in connection with and usable in the reactions of the polyvinyl alcohoHc resins with the cycHc acid anhydrides. Among these, preferably used herein are nitrogen atom- containing organic solvents such as amides and ureas, with N-methyl-2- pyrroHdone or mixed solvents containing the same being more preferred among others. The component (C) may be used alone or in any combination of at least two thereof.

The amount of the component (B) relative to the component (A) in the thermosetting binder resin composition of the present invention preferably ranges from 1 to 50 parts by mass, more preferably 3 to 30 parts by mass and particularly preferably 5 to 20 parts by mass per 100 parts by mass of the component (A). If the amount of the component (B) is less than one part by mass, the plasticity attained is insufficient, whUe if it exceeds 50 parts by mass, the thermosetting property of the resulting composition is reduced and this accordingly results in the reduction of the electrolysis solution resistance. The amount of the component (C) to be incorporated into the composition of the present invention should be any amount such that the concentration thereof is not too low since the component (C) is, if necessary, supplemented during the subsequent step for preparing a slurry of an electrode mix.

The thermosetting binder resin composition containing a thermosetting polyvinyl alcohoHc binder resin carrying thermosetting units represented by Formula (III) can impart a winding abiHty to the resulting electrodes containing the same even if any component (B) is not used.

The thermosetting binder resin composition of the present invention may, if necessary, comprise, in addition to the foregoing components (A), (B) and (C), a variety of additives such as thixotropic properties-imparting agents, thickening agents and dispersants for preventing any sedimentation of the active material present in the slurry of the electrode mix, anti-foaming agents for the improvement of the electrode-coating properties and levehng agents.

A first slurry of an electrode mix according to the present invention comprises at least a thermosetting binder resin composition containing the foregoing components (A), (B) and (C) and a positive electrode-active material or a negative electrode-active material.

In addition, a second slurry of an electrode mix according to the present invention comprises at least a thermosetting binder resin composition which comprises a thermosetting polyvinyl alcohoHc binder resin having thermosetting units represented by Formula (III) and a solvent, and a positive electrode-active material or a negative electrode-active material. The foregoing solvent is not particularly restricted, but examples thereof include water and alcohols as weU as organic solvents Hsted above in connection with and usable in the reaction with the alkenyl succinic acid anhydride (+ other cycHc acid anhydride). Among these, preferably used herein are nitrogen containing organic solvents such as amides and ureas, with N-methyl-2-pyrroHdone or mixed solvents containing the same being more preferred among others. These solvents may be used alone or in any combination of at least two thereof.

The foregoing positive and negative electrode-active materials are not restricted to specific ones inasmuch as they can reversibly insert and/or release Hthium ions through the charge-discharge cycle of the Hthium secondary battery. Examples of such positive electrode-active materials are preferably

Hthium-containing metal compound oxides comprising Hthium and at least one metal selected from the group consisting of iron, cobalt, nickel and manganese. On the other hand, examples of such negative electrode-active materials are preferably carbonaceous materials such as amorphous carbon, graphite, carbon fibers, coke and active carbon and it is also possible to use composite materials comprising such carbonaceous materials and metals such as sificon, tin and sUver or oxides thereof. These active materials may be used alone or in any combination of at least two thereof.

In this connection, the slurry of an electrode mix for positive electrodes may Hkewise comprise at least one auxiHary conductivity- imparting agent selected from the group consisting of, for instance, carbon black and acetylene black.

The volume ratio [binder resin/active material] of the thermosetting polyvinyl alcohoHc binder resin to the positive or negative electrode-active material present in the slurry of the electrode mix preferably ranges from [1/99] to [20/80]. If the volume ratio [binder resin/active material] is less than [1/99], the resulting layer of the electrode mix would undergo cracking, peeHng off and/or dropping out from the current coUector during the process for preparing a ceU and it is difficult to produce a normal ceU, whUe if it exceeds [20/80], there is observed such a tendency that the energy capacity of the resulting Hthium-containing secondary battery is reduced. In this respect, the rate of the solvent to be incorporated into the slurry may be arbitrarily selected, but should be such that the slurry is not excessively diluted therewith.

The electrodes of the present invention can be produced by applying the foregoing slurry of the electrode mix onto a current coUector and then drying the coated layer and the non-aqueous electrolysis solution-containing secondary battery of the present invention is prepared using such electrodes. The methods for preparing the electrodes and non-aqueous electrolysis solution-containing secondary battery of the present invention are not restricted to specific ones and they can be prepared according to any known methods, respectively.

The non- aqueous electrolysis solution used in the non- aqueous electrolysis solution-containing secondary battery of the present invention is not restricted to specific ones inasmuch as they can ensure the function of the resulting ceU as a secondary battery. Specific examples thereof are solutions obtained by dissolving electrolysis solutions such as LiC10₄, LiBF₄, Lil, LiCl₄, LiPF₆, LiCF₃S0₃, LiCF₃C0₂, LiAsF₆, LiSbF₆₎ LiB₁₀Cl₁₀, LiAlCl₄, LiCl, LiBr, LiB(C₂H₅)₄, LiCH₃S0₃, LiC₄F₉S0₃ and/or Li(CF₃S0₂)₂N in organic solvents, for instance, carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; lactones such as γ -butyrolactone; ethers such as trimethoxy-methane, 1,2-dimethoxy-ethane, diethyl ether, 2-ethoxy-ethane, tetrahydrofuran and 2-methyl-tetrahydrofuran; sulfoxides such as dimethyl sulfoxide; oxolanes such as 1,3-dioxolane and 4-methyl- 1,3-dioxolane; nitrogen atom-containing organic solvents such as acetonitrile, nitromethane and N-methyl-2-pyrroHdone; esters such as methyl formate, methyl acetate, butyl acetate, methyl propionate, ethyl propionate and phosphoric acid triesters; glymes such as diglyme, triglyme and tetraglyme; ketones such as acetone, diethyl ketone, methyl ethyl ketone and methyl isobutyl ketone; sulfones such as sulfolane; oxazoHdinones such as 3-methyl-2-oxazoHdinone; and sultones such as 1,3-propane-sultone, 4-butane-sultone and naphthasultone. Among these non-aqueous electrolysis solutions, preferred are those obtained by dissolving LiPF₆ in carbonates. The foregoing organic solvents used for preparing such non-aqueous electrolysis solutions may be used alone or in any combination. The solubiHty parameter (SP value) of the chain organic solvent for the non-aqueous electrolysis solution is preferably selected in such a manner that the difference between the SP values thereof and the binder resin used is not less than 3 (MJ/m³)^1/2. If the difference is less than 3 (MJ/m³)^1/2, the affinity of the resin for the solvent is extremely high and the resin is accordingly Hable to get swoUen. The SP values of dimethyl carbonate and diethyl carbonate used in Examples of the present invention as such chain organic solvents are 20.3 (MJ/m³)^1/2 and 18.0 (MJ/m⁸)¹'², respectively and that of ethylene carbonate as a cycHc solvent is 30.1 (MJ/m³)¹'². In this respect, the SP value of each binder resin can be calculated on the basis of the chemical structure thereof (OKITSU Toshinao: "The Role of SolubiHty Parameter (SP) in 1DP21 Polymer Blend", CoUected Resumes of The 2nd Polymer Materials Forum, 1993, pp. 167-168). Moreover, the SP values of organic solvents in electrolysis solutions are those purely thermodynamicaUy determined (A.F.M.Barton, Chem. Rev., 1975, 75:731; MUKAI Junji & KIN JO Noriyuki, "Practical Polymer Science for Engineers", Tokyo, Pubhshed by KODANSHA PubHshing Company, 1981, pp. 80-85; and MIHARA Kazuyuki, "Explanatory Paint and Varnish Technology", Tokyo, PubHshed by RIKO-SHUPPAN PubHshing Company, 1971, pp. 115-116). However, there is a considerable difference between the calculated SP value (14.1 (MJ/m³)¹'²) of PVDF and the practicaUy found value (23.2 (MJ/m³)¹'²) thereof and therefore, the SP value of PVDF disclosed in the present specification is the found one.

Moreover, in the non-aqueous electrolysis solution-containing secondary battery of the present invention, the degree of swelling of the thermosetting binder resin with respect to the electrolysis solution as determined at 50°C is desirably less than 10% and preferably less than 5%. If a thermosetting binder resin in an ideaUy adhered state excessively gets swoUen through the absorption of an electrolysis solution, there are observed incomplete contact between active materials and/or between active materials and a current coUector since the distances therebetween increase. In addition, if the adhesive force of a thermosetting binder resin in an electrolysis solution is reduced, the binder resin undergoes peeHng and this results in incomplete contact in the resulting ceU. For this reason, it is considered that the conductivity of the electrodes produced using the same is reduced, that the service or working time of the ceU is Hkewise reduced because of the reduction of the capacity of the ceU and that the output of the ceU is reduced due to an increase of the internal resistance of the ceU.

The thermosetting binder resin of the present invention desirably has a winding abiHty. A negative electrode (a blend of amorphous carbon having an average particle size of 20 zm and a thermosetting polyvinyl alcohoHc binder resin composition in a volume ratio (of sohd contents) of 90 : 10, obtained after drying in a vacuum at 150°C for 16 hours) is cut into a piece having a size of width 60 mm X length 20 mm in a dry room (temperature: 23 +2°C; humidity: 5 ±2%), wound on a stainless steal rod having a diameter of

4 mm φ in such a manner that the surface on which the layer of an electrode mix is provided is exposed, the both ends thereof are put on top of each other and then a weight of 100 g is loaded onto the same. Such a condition is maintained for one minute, the surface of the electrode mix layer is inspected for the presence of any apparent defect such as cracks or wrinkles and evaluated on the basis of the foUowing criteria: windable: there is not observed any crack and/or wrinkle on the surface of the electrode mix layer; un-windable: there are observed apparent defects.

Examples The present invention wiU hereunder be described in more detaU with reference to the foUowing Examples, but the present invention is not restricted to these specific Examples at aU.

Synthetic Example 1: Synthesis of Component (A) To a one Hter volume separable flask equipped with a stirring machine, a thermometer, a condenser, a distillation tube and a nitrogen gas- introduction tube, there were added 51.01 g of a polyvinyl alcohol (available from Unitika Ltd. under the trade name of Unitika Poval UF200G, the average degree of polymerization: 2000; the degree of saponification: 98 to 99 mole%; the content of adsorbed water and others (weight loss observed after drying on a hot plate of 150°C for 30 minutes): 5.3% by mass), 644 g of N- methyl-2-pyrroHdone (hereunder referred to as "NMP") as the component (C) and 10 g of toluene and the temperature was raised up to 195°C by heating over 30 minutes in a nitrogen gas stream with stirring. Moisture present in the system began to be distiUed in the form of an azeotropic mixture with toluene in the course of the heating and from an instance when the temperature exceeded about 185°C. The mixture was maintained at that temperature for 1 to 2 hours till all of the moisture was thus substantiaUy distiUed off from the system whUe refluxing the toluene, the toluene in the system was distiUed off and then the system was cooled down to 120°C. The distiUate (moisture and others) was found to be about 3 ml. Then, to the dehydrated solution of the polyvinyl alcohol maintained at 120°C, there was added 7.69 g of succinic acid anhydride (0.07 equivalent as expressed in terms of the amount of the acid anhydride groups per one equivalent of the alcohoHc hydroxyl groups of the polyvinyl alcohol), the mixture was maintained at that temperature for one hour to thus make the reaction proceed and then cooled down to room temperature to give a solution of the component (C) containing 8% by mass of the component (A).

The resulting component (A) was found to have a weight average molecular weight (as determined by GPC and more specificaUy, determined using, as an eluent, an aqueous solution prepared in such a manner that the concentration of sodium chloride as an emoUient agent was 0.1 mole/1, and a caHbration curve prepared using standard polyethylene oxide-polyethylene glycol, as expressed in terms of a polyethylene oxide-polyethylene glycol- reduced value) of 170,000 and an acid value of 78 KOH mg/g. In addition, the SP value of the resulting component (A) was found to be 25.4 (MJ/m³)¹'².

Preparation Example 1: Preparation of Polyvinyl Alcohol Aqueous Solution To a 0.3 Hter volume separable flask equipped with a stirring machine, a thermometer and a condenser, there were added 16.90 g of a polyvinyl alcohol identical to that used in Synthetic Example 1 and 183.1 g of pure water and the temperature was raised up to 95°C over 10 minutes with stirring. After completely dissolving the polyvinyl alcohol by maintaining the mixture at that temperature for one hour, the mixture was cooled to room temperature to give a 8% by mass aqueous solution of the polyvinyl alcohol. Separately, NMP was substituted for the pure water used above to prepare an NMP solution of the polyvinyl alcohol, but the whole system was soHdified in the course of cooHng the same to room temperature and therefore, such an NMP solution could not be prepared.

Synthetic Example 2: Synthesis of Component (B)

To a 0.3 Hter volume separable flask equipped with a stirring machine, a thermometer, a condenser and a nitrogen gas-introduction tube, there were added 109.29 g of a solvent-free lauryl acrylate-acryHc acid copolymer (avaUable from SOKEN Chemical Co., Ltd. under the trade name of ACTFLOW CBL3098, weight average molecular weight: 3100; acid value: 97 KOH mg/g) and 70.71 g (2 equivalents as expressed in terms of the amount of the epoxy groups per one equivalent of the carboxyl groups of the solvent-free lauryl acrylate-acryHc acid copolymer) of a bisphenol A type epoxy resin (available from Mitsui Chemicals, Inc. under the trade name of EPOMIK R140P, epoxy equivalent: 187 g/eq.), foUowed by the elevation of the temperature of the mixture up to 150°C over 10 minutes in a nitrogen gas stream with stirring. After the reaction of these components at that temperature for 2 hours, 77.14 g of NMP as the component (C) was added to the reaction system and then the mixture was cooled to room temperature to thus give a solution of the component (C) containing 70% by mass of the component (B).

The resulting component (B) was found to have a weight average molecular weight (as determined by GPC and more specificaUy, determined using, as an eluent, tetrahydrofuran and a caHbration curve prepared using standard polystyrene, as expressed in terms of a polystyrene-reduced value) of 21,000, an epoxy equivalent of 2377 g/eq and an acid value of less than 1 KOH mg/g.

The thermosetting properties and the electrolysis solution resistance of the component (A) prepared in Synthetic Example 1 were evaluated by comparing the component with the polyvinyl alcohol as the raw material. The foUowing are a method for preparing a film and methods for evaluating the thermosetting properties and the electrolysis solution resistance. The foUowing Table 1 shows the results obtained in the evaluation of the thermosetting properties and the electrolysis solution resistance.

Prep a ation of FUm

After uniformly casting a predetermined solution on a polyethylene terephthalate (hereunder referred to as "PET") film in such a manner that the film thickness as determined after drying and a heat treatment was equal to about 30 JUTΆ, the cast film was dried on a hot plate maintained at 100 °C for one hour under ordinary pressure. Then the dried film was subjected to a heat treatment in a vacuum dryer maintained at 150°C for 3 hours under reduced pressure, the heat-treated film was peeled off from the PET film and it was further vacuum-dried at 100°C for 2 hours to thus give a film.

Method for Evaluating Thermosetting Properties

After weighing out about 30 mg of the film prepared above in a completely dried atmosphere maintained at 25°C, immersing the weighed film in about 8 ml of NMP in a 13.5 ml glass screw bottle and tightly stopping the bottle, the bottle was heated in an oU bath maintained at 150°C for 30 minutes and the thermosetting properties of the film was evaluated according to the foUowing criteria: Insufficient thermosetting properties: a film sample is completely dissolved; good thermosetting properties: a film sample is not dissolved in the solvent and maintains its original shape.

Method for Evaluating Electrolysis solution Resistance

After accurately weighing out about 30 mg of the film prepared above in a completely dried atmosphere maintained at 25 °C , immersing the weighed film in about 8 ml of a non- aqueous electrolysis solution (a IM solution of Hthium hexafiuoro-phosphate in a 1/1/1 (volume ratio) mixed Hquid of ethylene carbonate/dimethyl carbonate/diethyl carbonate, avaUable from Kishida Chemical Co., Ltd., Hthium secondary battery electrolysis solution grade, those appearing in the foUowing description are shown in the same way) in a 13.5 ml glass screw bottle and tightly stopping the bottle, the bottle was stored in a thermostatic chamber maintained at 25°C and that maintained at 50°C over 24 hours.

Then the film were removed from the non-aqueous electrolysis solution in a completely dried atmosphere of 25°C, foUowed by wiping the non-aqueous electrolysis solution adhered to the film surface away with dry paper to thus determine any change of the mass. The degree of swelling due to the absorption of the non-aqueous electrolysis solution was calculated on the basis of the foUowing equation and the electrolysis solution resistance values of these films were evaluated on the foUowing criteria: A sample film whose degree of swelling at 50°C is smaUer than that observed at 25°C is considered to be dissolved in the electrolysis solution and therefore, it is judged to be bad in the electrolysis solution resistance; a sample film whose degree of sweUing at 50°C is not smaUer than that observed at 25°C, but exceeds 100% is Hkewise judged to be bad in the electrolysis solution resistance; a sample film whose degree of swelling at 50°C is not smaUer than that observed at 25°C and faUs within the range of from 10 to 100% is judged to be acceptable in the electrolysis solution resistance; and a film sample whose degree of swelling at 50°C is not smaUer than that observed at 25°C and is less than 10% is judged to be good in the electrolysis solution resistance.

Degree of SweUing (%) = [(Mass after immersion - mass before immersion)/mass before immersion] X 100

Table 1

The foregoing results clearly indicate that the component (A) used in the present invention has good thermosetting properties and electrolysis solution resistance, which cannot be achieved by the raw polyvinyl alcohol.

Example 1 (Preparation of Thermosetting Binder Resin Composition of the Invention) There were admixed 100 parts by mass (as expressed in terms of the reduced amount of the component (A)) of the solution of the component (C) containing 8% by mass of the component (A) prepared in Synthetic Example 1 with 10 parts by mass (as expressed in terms of the reduced amount of the component (B)) of the solution of the component (C) containing 70% by mass of the component (B) prepared in Synthetic Example 2 to give a thermosetting binder resin composition of the present invention.

The thermosetting binder resin composition prepared in Example 1 was inspected for the thermosetting properties and the electrolysis solution resistance whUe comparing them with those observed for PVDF. The results thus obtained are summarized in the foUowing Table 2.

Table 2

The foregoing results clearly indicate that the thermosetting plasticized polyvinyl alcohoHc binder resin composition of the present invention has good thermosetting properties and electrolysis solution resistance, which cannot be achieved by PVDF.

Example 2 (Preparation of Slurry of Positive Electrode Mix) There were admixed Hthium-rich Hthium manganese(HI,IN) oxide (Lii ₁₂Mn_{! 88}0₄), as a positive electrode-active material, having an average particle size of lOj m., an auxiHary conductivity -imparting agent (artificial graphite) having an average particle size of 3 /m and the thermosetting binder resin composition prepared in Example 1 in a volume ratio of 80 : 10 : 10 (soHd contents), foUowed by kneading the mixture whUe NMP was, if necessary, supplemented to prepare a slurry of positive electrode mix.

Examples 3 and 4 and Comparative Examples 1 to 6 (Preparation of Slurries of Positive Electrode Mixes) The same procedures used in Example 2 were repeated except for using components Hsted in the foUowing Table 3 to thus give corresponding slurries of positive electrode mixes having compositions specified in Table 3.

*: Comparative Example

Note 1: The auxiHary conductivity-imparting agent used in these Examples and Comparative Examples was identical to that used in Example 2. Note 2: The volume ratio of the positive electrode-active material, the auxiHary conductivity -imparting agent and the binder resin composition (soHd contents) was also identical to that used in Example 2.

Example 5 (Preparation of Slurry of Negative Electrode Mix)

There were admixed amorphous carbon having an average particle size of 20 //m as a negative electrode- active material and the thermosetting plasticized polyvinyl alcohoHc binder resin composition prepared in Example 1 in a volume ratio (of sofid contents) of 90 : 10, foUowed by kneading the mixture whUe NMP was, if necessary, supplemented to prepare a slurry of negative electrode mix.

Example 6 and Comparative Examples 7 to 10 (Preparation of Slurries of Negative ElectrodeMixes)

The same procedures used in Example 5 were repeated except for using components Hsted in the foUowing Table 4 to thus give corresponding slurries of negative electrode mixes having compositions specified in Table 4.

Table 4

*: Comparative Example Note 1: The volume ratio of the negative electrode-active material to the binder resin composition (soHd contents) was identical to that used in Example 5.

Example 7 (Preparation of Positive Electrode)

The slurry of the positive electrode mix prepared in Example 2 was appHed onto the both sides of a current coUector (an aluminum foU) having a thickness of 20 m such that the coated amount of the slurry was 290 g/m² per side and then the coated layer was dried to give an electrode mix layer. Then the resulting product was roUed using a roUer press machine such that the bulk density of the electrode mix was 2.6 g/cm³, foUowed by cutting the roUed product into strips each having a width of 54 mm to form electrode mix sheets in the form of tanzaku (a strip of fancy paper). After welding, under the appHcation of ultrasonics, a coUector tab of aluminum to an edge of each sheet, the resulting assembly was dried at 150°C for 16 hours in a vacuum for the removal of any volatile components such as the remaining solvents and the adsorbed moisture to thus give a positive electrode. Examples 8 and 9 and Comparative Examples 11 to 16 (Preparation of Positive Electrodes)

The same procedures used in Example 7 were repeated except for using slurries of positive electrode mixes detailed in the foUowing Table 5 to thus produce corresponding positive electrodes.

Table 5

Example 10 (Preparation of Negative Electrode)

The slurry of the negative electrode mix prepared in Example 5 was appHed onto the both sides of a current coUector (a copper foU) having a thickness of WjUτa such that the coated amount of the slurry was 65 g/m² per side and then the coated layer was dried to give an electrode mix layer. Then the resulting product was roUed using a roUer press machine such that the bulk density of the electrode mix was 1.0 g/cm³, foUowed by cutting the roUed product into strips each having a width of 56 mm to form electrode mix sheets in the form of tanzaku (a strip of fancy paper). After welding, under the appHcation of ultrasonics, a coUector tab of aluminum to an edge of each sheet, the resulting assembly was dried at 150°C for 16 hours in a vacuum for the removal of any volatile components such as the remaining solvents and the adsorbed moisture to thus give a negative electrode.

Example 11 and Comparative Examples 17 to 20 (Preparation of Negative Electrodes)

The same procedures used in Example 10 were repeated except for using slurries of negative electrode mixes detailed in the foUowing Table 6 to thus produce corresponding negative electrodes.

Table 6

The resulting electrodes were inspected for the conditions (such as the presence of peeHng and the presence of any crack) of the electrode mix (EM) layers and any change of the appearance observed after the immersion of these electrodes in a non-aqueous electrolysis solution. The results thus obtained are Hsted in the foUowing Table 7.

Table 7

*: Change of the appearance of an electrode observed after immersing in a non-aqueous electrolysis solution: After immersing the electrode in the electrolysis solution at 50 °C for 24 hours, the appearance thereof was observed under an electron microscope of 1000 magnifications. **: The term "surface coating" means that the binder covers the surface of the active material.

The results Hsted in Table 7 indicate that the electrodes prepared using PVDF (Comparative Examples) or only the component (A) cannot simultaneously satisfy the requirements for the adherence, flexibiHty and electrolysis solution resistance of the electrode mix layers, whUe the electrodes prepared using the thermosetting binder resin compositions of the present invention can simultaneously satisfy aU of these requirements.

Examples 12 to 18 and Comparative Examples 21 to 23 (Preparation of Lithium Secondary Batteries)

The positive electrodes prepared in the foregoing Examples 7 to 9 and Comparative Examples 11 to 13 and the negative electrodes prepared in Examples 10 and 11 and Comparative Examples 17 and 18 were variously combined as specified in the foUowing Table 8 and each pair of the electrodes was wound through microporous membrane separator of polyethylene having a thickness of 25 m and a width of 58 mm to form a series of spiral roUs. Each roU was inserted into a can for ceU, the nickel tab terminal, which had been welded to the copper foU or the current coUector for negative electrode in advance, was welded to the bottom of the can for ceU and the aluminum tab terminal, which had been welded to the aluminum foU or the current coUector for positive electrode in advance, was welded to a cap. Then 5 ml of a non-aqueous electrolysis solution (a IM solution of Hthium hexafluoro-phosphate in a 1/1/1 (volume ratio) mixed Hquid of ethylene carbonate/dimethyl carbonate/diethyl carbonate) was introduced into the can for ceU and then the can was caulked to tightly seal and to thus form a cyHndrical Hthium secondary battery having a diameter of 18 mm and a height of 65 mm.

The Hthium secondary batteries prepared in Examples 12 to 14 and Comparative Example 21 were constant voltage-charged at a charging current of 400 mA and a Hmit voltage of 4.2 V and then discharged at a discharge current of 800 mA tiU the voltage thereof reached the termination voltage of 2.7 V to thus determine the initial discharge capacities of these batteries.

In addition, the Hthium secondary batteries prepared in Examples 15 and 17 and Comparative Example 22 were constant voltage-charged at a charging current of 750 mA and a Hmit voltage of 4.2 V and then discharged at a discharge current of 1500 mA till the voltage thereof reached the termination voltage of 2.5 V to thus determine the initial discharge capacities of these batteries. Moreover, the Hthium secondary batteries prepared in Examples 16 and 18 and Comparative Example 23 were constant voltage-charged at a charging current of 900 mA and a Hmit voltage of 4.15 V and then discharged at a discharge current of 1800 mA tiU the voltage thereof reached the termination voltage of 3.0 V to thus determine the initial discharge capacities of these batteries.

The charge- discharge under these conditions was defined to be one cycle and such charge-discharge cycles were repeated at an ambient temperature of 50°C tUl the discharge capacity of the ceU was reduced to a level of less than 70% of the initial discharge capacity (a criteria for judging whether the high temperature service Hfe of a ceU ran down or not) to thus determine the number of charge-discharge cycles. The results thus obtained are Hsted in the foUowing Table 8. Table 8

*: Comparative Example

Mn: this means that the positive electrode-active material is Hthium-rich

Hthium manganese(III,IV) oxide.

Co: this means that the positive electrode-active material is Hthium cobalt(III) oxide

Ni: this means that the positive electrode- active material is Hthium nickel(III) oxide..

P: this means that the negative electrode-active material is amorphous carbon.

G: this means that the negative electrode-active material is artificial graphite.

PVA: this means that the binder resin composition used is the product of

Example 1 according to the present invention.

PVDF: this means that the binder resin composition used is PVDF.

The results Hsted in Table 8 indicate that the ceU of Comparative Example 21 comprising a combination of a positive electrode prepared using Hthium-rich Hthium manganese(III,IV) oxide as an active material and PVDF as a binder resin with a negative electrode comprising a combination of amorphous carbon as an active material and PVDF as a binder resin can repeatedly be charged and discharged only over 50 cycles tiU the service Hfe of the ceU ran down, whUe the Hthium secondary batteries of Examples 12 to 14 according to the present invention in which the thermosetting binder resin composition of the present invention is used in at least one of positive and negative electrodes have an improved or extended service Hfe on the order of not less than 250 cycles. When the batteries whose service Hfe ran down were taken to pieces, it was recognized that the negative electrode mix layer was peeled off from the copper foU as the current coUector, among others, in the ceU of Comparative Example 21 and there was observed deposition of metal Hthium on that portion, while there were not observed such defects at aU in the Hthium secondary batteries of Examples 12 and 14.

From the foregoing, it can be confirmed that the Hthium secondary battery, which makes use of the thermosetting binder resin composition of the present invention, is exceUent in the electrolysis solution resistance at a high temperature (50°C) in the proximity to the upper Hmit of the ceU- operating temperature, that good adherence at the boundary between the current coUector and the electrode mix layers and between the active materials present in the electrode mix layers is ensured since the degree of sweUing through the absorption of an electrolysis solution is considerably low and that the reduction of the discharge capacity of the ceU is thus significantly retarded. Example 19 (Preparation of Thermosetting Polyvinyl AlcohoHc Binder Resin) To a 0.5 Hter volume separable flask equipped with a stirring machine, a thermometer, a condenser, a distillation tube and a nitrogen gas- introduction tube, there were added 24.2 g of a polyvinyl alcohol (available from Unitika Ltd. under the trade name of Unitika Poval UF200G, the average degree of polymerization: 2000; the degree of saponification: 98 to 99 mole%; the content of adsorbed water and others (weight loss observed after drying on a hot plate of 150°C for 30 minutes): 6.3% by mass), as a raw material, 322 g of N-methyl-2 -pyrroHdone (NMP) as a solvent and 10 g of toluene as a solvent for azeotropic dehydration and the temperature was raised up to 190°C by heating over 30 minutes in a nitrogen gas stream with stirring. Moisture present in the system began to be distiUed off in the form of an azeotropic mixture with toluene in the course of the heating and from an instance when the temperature exceeded about 180°C. The mixture was maintained at that temperature for 1 to 2 hours tiU aU of the moisture was thus substantiaUy distiUed off from the system whUe refluxing the toluene, the toluene in the system was distiUed off and then the system was cooled down to 120°C. The distillate (moisture and others) was found to be about 2 ml. Then, to the dehydrated solution of the polyvinyl alcohol maintained at 120 °C, there was added 2.75 g of dodecenyl succinic acid anhydride (available from WAKO Pure Chemical Co., Ltd., electron microscope grade, 0.02 equivalent as expressed in terms of the amount of the acid anhydride groups per one equivalent of the alcohoHc hydroxyl groups of the polyvinyl alcohol), the mixture was maintained at that temperature for one hour to thus make the reaction proceed. Subsequently, 2.58 g of succinic acid anhydride (0.05 equivalent as expressed in terms of the amount of the acid anhydride groups per one equivalent of the alcohoHc hydroxyl groups of the polyvinyl alcohol) was added to the reaction system, the mixture was maintained at that temperature for one hour to thus make the reaction proceed and then cooled down to room temperature to give a thermosetting polyvinyl alcohoHc binder resin (an NMP solution having a resin content of 8% by mass) according to the present invention.

The resulting product of the present invention was found to have a weight average molecular weight (as determined by GPC and more specificaUy, determined using, as an eluent, an aqueous solution prepared in such a manner that the concentration of sodium chloride as an emollient agent was 0.1 mole/1, and a caHbration curve prepared using standard polyethylene oxide-polyethylene glycol, as expressed in terms of a polyethylene oxide-polyethylene glycol-reduced value) of 73,000 and an acid value of 78 KOH mg/g.

In addition, the SP value of the resulting thermosetting polyvinyl alcohoHc binder resin was found to be 25.3 (MJ/m⁸)¹'².

The thermosetting properties and the electrolysis solution resistance of the product obtained in Example 19 were evaluated by comparing it with the polyvinyl alcohol as the raw material (Raw PVA) prepared in Preparation Example 1 and PVDF. The method for preparing a film and the methods for evaluating the thermosetting properties and the electrolysis solution resistance are identical to those described above. The foUowing Table 9 shows the results obtained in the evaluation of the thermosetting properties and the electrolysis solution resistance. Table 9

The foregoing results indicate that the thermosetting polyvinyl alcohoHc binder resin carrying thermosetting units represented by Formula (III) possesses good thermosetting properties and good electrolysis solution resistance which can never be attained by polyvinyl alcohol as the raw material and PVDF.

Example 20 (Preparation of Slurry of Positive Electrode Mix) There were admixed Hthium-rich Hthium manganese(III,IV) oxide

(Li₁₁₂Mn₁₈₈0₄), as a positive electrode-active material, having an average particle size of 10 ju , an auxiHary conductivity -imparting agent (artificial graphite) having an average particle size of 3 zm and the thermosetting polyvinyl alcohoHc binder resin (an NMP solution having a resin content of 8% by mass) prepared in Example 19 in a volume ratio of 80 : 10 : 10 (soHd contents), foUowed by kneading the mixture whUe NMP was, if necessary, supplemented to the mixture to prepare a slurry of positive electrode mix. Examples 21 and 22 and Comparative Examples 24 to 26 (Preparation of Slurries of Positive Electrode Mixes)

The same procedures used in Example 20 were repeated except for using components Hsted in the foUowing Table 10 to thus give corresponding slurries of positive electrode mixes having compositions specified in Table 10.

Table 10

*: Comparative Example

Note 1: The auxiHary conductivity-imparting agent used is identical to that used in Example 20.

Note 2: The relative volume rate of the positive electrode- active material, the auxiHary conductivity -imparting agent and the binder resin (soHd contents) is Hkewise identical to that used in Example 20.

Example 23 (Preparation of Slurries of Negative Electrode Mixes)

There were admixed amorphous carbon having an average particle size of 20 j m. as a negative electrode-active material and the thermosetting polyvinyl alcohoHc binder resin (an NMP solution having a resin content of 8% by mass) prepared in Example 19 in a volume ratio (of soHd contents) of 90 : 10, foUowed by kneading the mixture whUe NMP was, if necessary, supplemented to prepare a slurry of negative electrode mix.

Example 24 and Comparative Examples 27 to 29 (Preparation of Slurries of Negative Electrode Mixes)

The same procedures used in Example 23 were repeated except for using components Hsted in the foUowing Table 11 to thus give corresponding slurries of negative electrode mixes having compositions specified in Table 11.

Table 11

*: Comparative Example

Note 1: The volume ratio of the negative electrode-active material to the binder resin (sofid contents) was identical to that used in Example 23.

Example 25 (Preparation of Positive Electrode)

The slurry of the positive electrode mix prepared in Example 20 was appHed onto the both sides of a current coUector (an aluminum foU) having a thickness of 20 m such that the coated amount of the slurry was 290 g/m² per side and then the coated layer was dried to give an electrode mix layer. Then the resulting product was roUed using a roUer press machine such that the bulk density of the electrode mix was 2.6 g/cm³, foUowed by cutting the roUed product into strips each having a width of 54 mm to form electrode mix sheets in the form of tanzaku (a strip of fancy paper). After welding, under the appHcation of ultrasonics, a coUector tab of aluminum to an edge of each sheet, the resulting assembly was dried at 150°C for 16 hours in a vacuum for the removal of any volatile components such as the remaining solvents and the adsorbed moisture to thus give a positive electrode.

Examples 26 and 27 and Comparative Examples 30 to 32 (Preparation of Positive Electrodes)

The same procedures used in Example 25 were repeated except for using slurries of positive electrode mixes detaUedin the foUowing Table 12 to thus produce corresponding positive electrodes.

Table 12

Example 28 (Preparation of Negative Electrode)

The slurry of the negative electrode mix prepared in Example 23 was appHed onto the both sides of a current coUector (a copper foU) having a thickness of 10 zm such that the coated amount of the slurry was 65 g/m² per side and then the coated layer was dried to give an electrode mix layer. Then the resulting product was roUed using a roUer press machine such that the bulk density of the electrode mix was 1.0 g/cm³, foUowed by cutting the roUed product into strips each having a width of 56 mm to form electrode mix sheets in the form of tanzaku (a strip of fancy paper). After welding, under the appHcation of ultrasonics, a coUector tab of aluminum to an edge of each sheet, the resulting assembly was dried at 150°C for 16 hours in a vacuum for the removal of any volatile components such as the remaining solvents and the adsorbed moisture to thus give a negative electrode.

Example 29 and Comparative Examples 33 to 35 (Preparation of Negative Electrodes)

The same procedures used in Example 28 were repeated except for using slurries of negative electrode mixes detaUed in the foUowing Table 13 to thus produce corresponding negative electrodes.

Table 13

The resulting electrodes were inspected for the conditions (such as the presence of peeHng, the presence of any crack) of the electrode mix (EM) layers and any change of the appearance observed after the immersion of these electrodes in a non-aqueous electrolysis solution. The results thus obtained are Hsted in the foUowing Table 14. Table 14

*: Change of the appearance of an electrode observed after immersing in a non-aqueous electrolysis solution: After immersing the electrode in the electrolysis solution at 50 °C for 24 hours, the appearance thereof was observed under an electron microscope of 1000 magnifications.

The above results indicate that the electrodes prepared using PVDF (Comparative Examples) or the polyvinyl alcohol as the raw material cannot simultaneously satisfy the requirements for the adherence, flexibiHty and electrolysis solution resistance of the electrode mix layers, whUe the electrodes prepared using the thermosetting polyvinyl alcohoHc binder resin of the present invention can simultaneously satisfy aU of these requirements.

Examples 30 to 36 and Comparative Examples 36 to 38 (Preparation of Lithium Secondary Batteries) The positive electrodes prepared in the foregoing Examples 25 to 27 and Comparative Examples 30 to 32 and the negative electrodes prepared in Examples 28 and 29 and Comparative Examples 33 and 34 were variously combined as specified in the foUowing Table 15 and each pair of the electrodes was wound through microporous membrane separator of polyethylene having a thickness of 25 jϋira and a width of 58 mm to form a series of spiral roUs. Each roU was inserted into a can for ceU, the nickel tab terminal, which had been welded to the copper foU or the current coUector for negative electrode in advance, was welded to the bottom of the can for ceU and the aluminum tab terminal, which had been welded to the aluminum foU or the current coUector for positive electrode in advance, was welded to a cap. Then 5 ml of a non-aqueous electrolysis solution (a IM solution of Hthium hexafluoro-phosphate in a 1/1/1 (volume ratio) mixed Hquid of ethylene carbonate/dimethyl carbonate/diethyl carbonate) was introduced into the can and then the can was caulked to tightly seal and to thus form a cylindrical Hthium secondary battery having a diameter of 18 mm and a height of 65 mm.

The Hthium secondary batteries prepared in Examples 30 to 32 and Comparative Example 36 were constant voltage-charged at a charging current of 400 mA and a Hmit voltage of 4.2 V and then discharged at a discharge current of 800 mA tiU the voltage thereof reached the termination voltage of 2.7 V to thus determine the initial discharge capacities of these batteries.

In addition, the Hthium secondary batteries prepared in Examples 33 and 35 and Comparative Example 37 were constant voltage-charged at a charging current of 750 mA and a Hmit voltage of 4.2 V and then discharged at a discharge current of 1500 mA tiU the voltage thereof reached the termination voltage of 2.5 V to thus determine the initial discharge capacities of these batteries.

Moreover, the Hthium secondary batteries prepared in Examples 34 and 36 and Comparative Example 38 were constant voltage-charged at a charging current of 900 mA and a Hmit voltage of 4.15 V and then discharged at a discharge current of 1800 mA tiU the voltage thereof reached the termination voltage of 3.0 V to thus determine the initial discharge capacities of these batteries.

The charge-discharge under these conditions was defined to be one cycle and such charge- discharge cycles were repeated at an ambient temperature of 50°C tiU the discharge capacity of the ceU was reduced to a level of less than 70% of the initial discharge capacity (a criteria for judging whether the high temperature service Hfe of a ceU ran down or not) to thus determine the number of charge-discharge cycles. The results thus obtained are Hsted in the foUowing Table 15.

Table 15

*: Comparative Example

Mn: this means that the positive electrode-active material is Hthium-rich

Hthium manganese(III,IV) oxide.

Co: this means that the positive electrode- active material is Hthium cobalt(III) oxide..

Ni: this means that the positive electrode-active material is Hthium nickel(III) oxide_*

P: this means that the negative electrode-active material is amorphous carbon. G: this means that the negative electrode-active material is artificial graphite.

PVA: this means that the binder resin used is the product of Example 19 according to the present invention.

PVDF: this means that the binder resin used is PVDF.

The results Hsted in Table 15 indicate that the ceU of Comparative

Example 36 comprising a combination of a positive electrode prepared using

Hthium-rich Hthium manganese(III,IV) oxide as an active material and

PVDF as a binder resin with a negative electrode comprising a combination of amorphous carbon as an active material and PVDF as a binder resin can repeatedly be charged and discharged only over 50 cycles tiU the service Hfe of the ceU ran down, whUe the Hthium secondary batteries of Examples 30 to

32 according to the present invention in which the thermosetting polyvinyl alcohoHc binder resin of the present invention is used in at least one of positive and negative electrodes have an improved or extended service Hfe on the order of not less than 250 cycles. When the batteries whose service Hfe ran down were taken to pieces, it was recognized that the negative electrode mix layer was peeled off from the copper foU as the current coUector among others in the ceU of Comparative Example 36 and there was observed deposition of metal Hthium on that portion, whUe there were not observed such defects at aU in the Hthium secondary batteries of Examples 30 and 32.

From the foregoing, it has been confirmed that the Hthium secondary battery, which makes use of the thermosetting polyvinyl alcohoHc binder resin of the present invention, is exceUent in the electrolysis solution resistance at a high temperature (50°C) in the proximity to the upper Hmit of the ceU-operating temperature, that good adherence at the boundary between the current coUector and the electrode mix layers and between the active materials present in the electrode mix layers is ensured since the degree of sweUing through the absorption of an electrolysis solution is considerably low and that the reduction of the discharge capacity of the ceU is thus significantly retarded.

Industrial AppHcabiHty

The present invention provides a thermosetting polyvinyl alcohoHc binder resin, which is exceUent in the electrolysis solution resistance at a high temperature (50 °C) in the proximity to the upper Hmit of the ceU- operating temperature of the Hthium secondary battery, which never causes any cracking, peeHng off and dropping out of the electrode mix layer containing the same during the preparation of batteries and which has good softness and flexibiHty. Moreover, the use of electrodes prepared from slurries of electrode mixes containing the thermosetting polyvinyl alcohoHc binder resin permits the production of a non-aqueous electrolysis solution- containing secondary battery, whose reduction of the energy capacity in the charge-discharge cycles at 50 °C can significantly be retarded and whose service Hfe can substantiaUy be extended, as compared with the conventional batteries produced using PVDF as a binder resin.

Claims

1. A thermosetting binder resin composition which comprises (A) a thermosetting polyvinyl alcohoHc binder resin, (B) an acryHc resin plasticizer and (C) a solvent.

2. The thermosetting binder resin composition of claim 1, wherein the component (A) has thermosetting units represented by the foUowing general formula (I):

wherein R represents a divalent organic group.

3. The thermosetting binder resin composition of claim 1, wherein the component (B) is a polymerized product derived from a monomer represented by the foUowing general formula (II):

I ( ii )

CH₂=C-COO-R₂ wherein Rj represents a hydrogen atom or a methyl group and R₂ represents a hydrogen atom, a glycidyl group or an alkyl group having 6 to 18 carbon atoms, or a derivative thereof.

4. The thermosetting binder resin composition as set forth in any one of claims 1 to 3, wherein the component (C) is a nitrogen atom-containing organic solvent or a mixed solvent containing the same.

5. A thermosetting binder resin composition which comprises a thermosetting polyvinyl alcohoHc binder resin having thermosetting units represented by the foUowing general formula (III):

wherein one of R₃ and R₄ represents a hydrogen atom and the other represents an alkenyl group, and a solvent.

6. The thermosetting binder resin composition of claim 5, wherein the alkenyl group in the thermosetting unit is a dodecenyl group.

7. A thermosetting binder resin composition which comprises a thermosetting binder resin whose solubiHty parameter ranges from 24.5 to

26.5 (MJ/m³)¹'² and a solvent.

8. A slurry of an electrode mix which comprises a thermosetting binder resin composition as set forth in any one of claims 1 to 7 and a positive or negative electrode-active material.

9. The slurry of an electrode mix of claim 8, wherein the positive electrode-active material is a Hthium-containing metal compound oxide capable of reversibly inserting and releasing Hthium ions by charge- discharge cycles.

10. The slurry of an electrode mix of claim 8, wherein the negative electrode-active material is a carbonaceous material capable of reversibly inserting and releasing Hthium ions by charge-discharge cycles.

11. An electrode characterized in that it is prepared by applying the slurry of an electrode mix as set forth in any one of claims 8 to 10 onto a current coUector and then drying the coated layer of the slurry.

12. A non-aqueous electrolysis solution-containing secondary battery which comprises the electrode as set forth in claim 11.

13. A non-aqueous electrolysis solution-containing secondary battery which comprises electrodes and an electrolysis solution containing a chain organic solvent, wherein the electrode is one prepared by applying a slurry of an electrode mix, which comprises a thermosetting binder resin composition and a positive or negative electrode-active material, onto a current coUector and then drying the coated slurry and wherein the difference between the solubiHty parameter (SP value) of the thermosetting binder resin and the SP value of the chain organic solvent is not less than 3 (MJ/m⁸)¹'².

14. The non-aqueous electrolysis solution-containing secondary battery of claim 13, wherein the degree of sweUing, as determined at 50°C, of the thermosetting binder resin with respect to the electrolysis solution is not smaUer than that as determined at 25°C and the former is less than 10%.

15. The non-aqueous electrolysis solution-containing secondary battery of claim 13, wherein the thermosetting binder resin has a winding abiHty.

16. The non-aqueous electrolysis solution-containing secondary battery of claim 13, wherein the thermosetting binder resin is a thermosetting polyvinyl alcohoHc binder resin having thermosetting units represented by the foUowing general formula (III):

17. The non-aqueous electrolysis solution-containing secondary battery of claim 16, wherein the alkenyl group present in the thermosetting unit is a dodecenyl group.

18. The non-aqueous electrolysis solution-containing secondary battery of claim 13, wherein the thermosetting binder resin composition comprises (A) a thermosetting polyvinyl alcohoHc binder resin, (B) an acryHc resin plasticizer and (C) a solvent.

20. The thermosetting polyvinyl alcohoHc binder resin of claim 19, wherein the alkenyl group present in the thermosetting unit is a dodecenyl group.