JPH06333569A - Nonaqueous secondary battery - Google Patents

Abstract

PURPOSE:To improve the charge and discharge cycle characteristic of an nonaqueous secondary battery by forming at least one of negative electrode active materials from a metal oxide, and forming the current collector of a negative electrode from a specified metal or its alloy within a specified thickness range. CONSTITUTION:At least one of negative electrode active materials contained in the negative electrode of a secondary battery consisting of a positive electrode, the negative electrode and an electrolyte is formed of a metal oxide. The current collector of the negative electrode is formed of copper, nickel, titanium alloys thereof, or stainless steel having a thickness of 5-200mu, and thermally treated at a temperature of 100-500 deg.C. As preferable metal oxide negative electrode active materials, lithium-contained transition metal oxides represented by LieMfOg (M=at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Wb, Mo, and W; e=0.7-3; f=1 or 2; g=1-5.5) which are obtained by baking are given.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention improves charge / discharge characteristics,
The present invention also relates to a secondary battery with improved safety.

[0002]

2. Description of the Related Art Lithium metal and lithium alloys are typically used as a negative electrode active material for a lithium secondary battery. When they are used, lithium metal grows in a dendritic form during charge / discharge, causing an internal short circuit, The activity of the dendritic metal itself is high and there is a danger of ignition. On the other hand, recently, a baked carbonaceous material capable of inserting and extracting lithium has come into practical use. The disadvantage of this carbonaceous material is that it is electrically conductive, which means that lithium metal is deposited on the carbonaceous material during overcharging or rapid charging, which eventually deposits dendritic metal. It will be. To avoid this, reduce the amount of positive electrode active material,
A method of preventing overcharge is adopted, but in this method, the amount of the active material is limited, so that the discharge capacity is limited. Further, since the carbonaceous material has a relatively small specific gravity, the discharge capacity is limited in the double sense that the capacity per volume is low.

On the other hand, as negative electrode active materials other than lithium metal, lithium alloys, and carbonaceous materials, TiS ₂ and LiTiS capable of absorbing and desorbing lithium ions.
₂ (US Pat. No. 983,476), LixM ₂ O ₃ (M = transition metal US Pat. No. 446,447) into which lithium is electrochemically inserted, and lithium compounds of WO ₃ and Fe ₂ O ₃ (Japanese Patent Application Laid-Open No. Hei ₃ (1998)). 112070), Nb ₂ O ₅ (JP-B-62-
59412, JP-A-2-82447, and chemically synthesized Li _0.1 V ₂ O ₅ (JP-A-63-210,028,
Said 63-211,564, the 63-211,568, _{JP-A-1-294,364), LiNi x Co 1-} x O 2 (0
≤x <1 JP-A-1-120,765), iron oxide, Fe
O, Fe ₂ O ₃ , Fe ₃ O ₄ , cobalt oxide, CoO, Co
₂ O ₃ and Co ₃ O ₄ (JP-A-3-291,862) are known. These negative electrode active materials are less likely to deposit lithium metal due to overcharging or rapid charging, and are more safe than carbonaceous materials.

[0004]

On the other hand, the use of aluminum as the material for the collector of the electrode is disclosed in Japanese Patent Publication No. 4-525.
92, Japanese Patent Publication No. 52-16204, and Japanese Patent Laid-Open No. 55-
As disclosed in Japanese Patent No. 69964, it is well known that it is suitable as a current collector because of its excellent corrosion resistance. However, when aluminum is used as the current collector of the negative electrode containing the negative electrode active material, lithium ions are not occluded in the negative electrode active material during charging and alloyed as lithium metal in the current collector (aluminum-lithium alloy). ) Will be done. When charging and discharging are repeated, the current collector alloys ← → is repeatedly melted, and as a result, the shape of the current collector collapses,
At the end, there was a problem that disconnection occurred and conduction failure occurred.

[0005]

The present invention relates to a secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein at least one of the negative electrode active materials contained in the negative electrode comprises a metal oxide, and It has been achieved by a secondary battery characterized in that the body is made of copper, nickel, titanium or alloys thereof having a thickness of 5 to 200 μ.

Copper or an alloy thereof is mentioned as one of the materials for the negative electrode current collector used in the present invention. Preferred metals alloying with copper include Zn, Ni, Sn, Al, etc. , P, Pb, Mn, Ti, Cr,
A small amount of Si, As, etc. may be added. Another material of the negative electrode current collector used in the present invention is titanium or its alloy. Since titanium has a stable oxide film, it is completely resistant to corrosion in an oxidizing environment and can prevent dissolution during deep discharge or over discharge in the present embodiment. Further, in order to further improve the corrosion resistance, Ta,
An alloy with Pd, Mo, Ni or Zr may be used. Other metals to be alloyed include Al, Cr, Sn,
There are Fe, Si, Mn, Cu, V, Bi and the like. Another material for the negative electrode current collector used in the present invention is nickel or its alloy. Since the nickel oxide film is dense, has a large protective action, and has excellent conductivity, it is preferable as a current collector for the negative electrode active material of the present invention. An alloy mainly composed of nickel can also be used, for example, Cu,
Alloys with Cr, Fe, Mo, Si, W or Ta are preferred. Alternatively, an alloy with Al, Nb, Mn, Co or the like may be used.

Another material of the negative electrode current collector used in the present invention is stainless steel. Stainless steel is Fe—Cr steel containing about 11% or more chromium and having excellent weather resistance and corrosion resistance. This alloy forms a very thin passivation film on its surface in the atmosphere, and subsequent corrosion hardly occurs. Stainless steel is classified into martensitic, ferritic, austenitic, ferritic-austenitic, and semi-austenitic based on its metal structure. What is austenitic stainless steel?
It belongs to -Cr-Ni system or Fe-Cr-Mn system and shows austenite structure, and has high strength and excellent ductility in a wide temperature range from low temperature to high temperature. The solid solution heat treatment for quenching from a temperature of about 1000 degrees Celsius or higher gives a nonmagnetic complete austenite structure, and excellent corrosion resistance and maximum ductility are obtained. A preferred composition of the stainless steel used in the present invention is, for example, JI.
S standard SUS304, SUS316, SUS316
L, SUS430 and the like. Particularly preferably S
It is an austenitic stainless steel containing Mo such as US316 and SUS316L. The molybdenum content is preferably 1 to 7% by weight, more preferably 1.2 to 6% by weight, most preferably 1.7 to 4% by weight. The nickel content is preferably 8 to 18% by weight, more preferably 9 to 16% by weight, most preferably 10 to 15% by weight. The chromium content is preferably 11 to 26% by weight, more preferably 15 to 20% by weight, most preferably 16 to 19% by weight. When the combination of the contents of nickel, chromium and molybdenum is described in this order, it is preferably 8 to 18% by weight, 11 to 26% by weight, 1 to 7% by weight, more preferably 9 to 16% by weight, 15 to 20% by weight. , 1.2 to 6% by weight, most preferably 10
To 15% by weight, 16 to 19% by weight, 1.7 to 4% by weight.

By the way, Japanese Patent Application Laid-Open No. 2-174078 discloses the use of molybdenum-containing steel, which is used as a sealing plate constituent member and is completely different from the current collector of the present invention. is there. The patent also uses a metal oxide as the negative electrode active material, but this is substantially limited to niobium pentoxide, and the lithium-containing transition metal oxide obtained by firing of the present invention is completely novel. In this respect, too, the configuration of the present invention is different.

The negative electrode current collector used in the present invention may be heat treated at a temperature of 100 ° C. or higher as a means for improving the cycle characteristics, and the preferable heat treatment temperature range is 100 ° C. to 300 ° C., more preferably 150 ℃ ~
It is 250 degreeC. The heat treatment time varies depending on the shape and size of the electrode or the type of the heat treatment apparatus, but the preferable range is 1 minute to 24 hours, and more preferably 1 minute to 18 hours. The heat treatment may be performed in a bare state before applying the negative electrode mixture, or may be performed in a state of the negative electrode plate (sheet) after applying. By the way, JP-A-60-195
No. 874 discloses that annealed stainless steel is used as a negative electrode current collector. Annealing (annealing) means heat treatment at a temperature not lower than the transition temperature of metal, and the temperature range of the present invention is transition. Since it is below the temperature, it is completely different.

The current collector described in the present invention can be used both as a support for electrodes and as a lead terminal. When used as a support for the electrode, the shape of the current collector is preferably foil, expanded metal, punching metal, foam metal or mesh, and most preferably foil. The thickness of the current collector used in the present invention is preferably thin in order to increase the filling amount of the active material, and specifically 5 μ to 2 μm.
00μ is preferable, more preferably 10μ to 100
μ, most preferably 10 μ to 50 μ. When the current collector used in the present invention is a continuous body such as a foil, the surface may be physically or chemically treated to change the surface roughness, or the thickness of the oxide film may be adjusted, and the conductivity may be adjusted. Apply a coating,
You may coat with silver, gold, TiC, TiN etc.

The material for the current collector of the positive electrode is preferably aluminum, titanium, nickel, their alloys or stainless steel, and most preferably aluminum. As the shape of the positive electrode current collector, the same shape as the negative electrode current collector can be used, and the foil shape is most preferable.

The preferred metal oxide negative electrode active material used in the present invention is a lithium-containing transition metal oxide obtained by firing. The preferred lithium-containing transition metal oxide negative electrode active material used in the present invention is Li _e M _f.
O _g (where M = Ti, V, Cr, Mn, Fe, Co,
At least one selected from Ni, Nb, Mo, W),
Examples include e = 0.7 to 3, f = 1 or 2, and g = 1 to 5.5. A more preferable lithium-containing transition metal oxide negative electrode active material used in the present invention is Li _e M _f O _g.
(Here, at least one selected from M = V, Mn, Fe, Co, and Ni), e = 0.7 to 3, f = 1 or 2, and g = 1 to 5.5. Particularly preferred lithium-containing transition metal oxide anode active material used in the present _{invention, Li p Co q V 1-} q O r ( wherein p = 0.7 to
3, q = 0 to 1, r = 1.2 to 5.5).
The most preferred lithium-containing transition metal oxide anode active material used in the present _{invention, Li p Co q V 1-} q O r ( wherein p = 0.8~2.5, q = 0.02~0.98 , R =
1.3-4.5). As a further most preferred lithium-containing transition metal oxide anode active material used in the present _{invention, Li p Co g V 1-} q O r ( wherein p = 0.8 to
2.5, q = 0.1 to 0.9, r = 1.3 to 4.5).

The positive electrode active material used in the present invention is preferably a lithium-containing transition metal oxide. Preferred lithium-containing transition metal oxide positive electrode active materials used in the present invention include lithium-containing Ti, V, Cr, Mn, Fe and Co.
The oxide containing Ni, Cu, Mo, W, the lithium-containing transition metal oxide negative electrode active material, lithium-containing Ti,
V, Cr, Mn, Fe, Co, Ni, Cu, Nb, M
Examples thereof include oxides containing o and W. A more preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is Li _x M _y O _z (where M = Ti, V, Cr, M
n, Fe, Co, Ni, Mo, W), x = 0.6 to 2.1, y = 1 or 2, z
= 1.5 to 5). A particularly preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is Li _x M _y O _z (where M = V, Mn, Fe, C
o, at least one selected from Ni), x = 0.6 to
2.1, y = 1 or 2, and z = 1.5 to 5). The most preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is Li _x CoO ₂ , Li
_x Co _a Ni _1-a O ₂ , Li _x Mn ₂ O ₄ , Li _x Co _b V _1-b O
_z (where x = 0.7 to 1.1.04, a = 0.1
0.9, b = 0.9-0.98, z = 2.02-2.
3) can be given.

The positive electrode active material of the present invention is a method of chemically inserting lithium into a transition metal oxide, a method of electrochemically inserting lithium into a transition metal oxide, or a method of firing a lithium compound and a transition metal compound. Can be obtained by As a method for chemically inserting lithium into the transition metal oxide in the positive electrode active material of the present invention, a method obtained by reacting lithium metal, a lithium alloy, or butyl lithium with the transition metal oxide is preferable. The positive electrode active material of the present invention is preferably obtained by a method of firing a lithium compound and a transition metal compound. The positive electrode active material and the negative electrode active material of the present invention can be obtained by firing a mixture of a lithium compound and a transition metal compound described below. For example, as the lithium compound, an oxygen compound,
Examples include oxyacid salts and halides. As the transition metal compound, a divalent to hexavalent transition metal oxide, the same transition metal salt, or the same transition metal complex salt is used. Preferred lithium compounds used in the present invention include lithium hydroxide, lithium carbonate, lithium nitrate, lithium sulfate, lithium sulfite, lithium phosphate, lithium tetraborate, lithium chlorate, lithium perchlorate, lithium thiocyanate, lithium formate, Lithium acetate, lithium oxalate, lithium citrate, lithium lactate, lithium tartrate, lithium pyruvate, lithium trifluoromethanesulfonate, lithium tetraborate, lithium hexafluorophosphate, lithium fluoride, lithium chloride, lithium bromide, iodine Lithium fluoride is an example.

Preferred transition metal compounds used in the present invention include TiO ₂ , lithium titanium fluoride, titanium oxide acetylacetonate, titanium tetrachloride, titanium tetraiodide, lithium titanium oxalate and VO _d (d = 2 to 2). .5),
VO _d lithium compound, vanadium hydroxide, ammonium metavanadate, ammonium orthovanadate,
Ammonium pyrovanadate, vanadium oxosulfate,
Vanadium oxytrichloride, vanadium tetrachloride, lithium chromate, ammonium chromate, cobalt chromate,
Chromium acetylacetonate, MnO ₂ , Mn ₂ O ₃ , manganese hydroxide, manganese carbonate, manganese nitrate, manganese sulfate, ammonium manganese sulfate, manganese sulfite, manganese phosphate, manganese borate, manganese chlorate, manganese perchlorate, thiocyanate. Manganese, manganese formate, manganese acetate, manganese oxalate, manganese citrate, manganese lactate, manganese tartrate, manganese stearate, manganese fluoride, manganese chloride, manganese bromide, manganese iodide, manganese acetylacetonate, iron oxide (2, Three
Valence), iron trioxide, iron hydroxide (2,3 valence), iron chloride (2,3 valence), iron bromide (2,3 valence), iron iodide (2,3 valence)
Value), iron sulfate (2,3 value), ammonium iron sulfate (2,3)
Trivalent), iron nitrate (2,3 valent) iron phosphate (2,3 valent), iron perchlorate, iron chlorate, iron acetate (2,3 valent), iron citrate (2,3 valent), kuen Ammonium ferric acid (2,3 valent),
Iron oxalate (2,3 valent), ammonium iron oxalate (2,3)
Value), Co ₂ O ₃ , Co ₃ O ₄ , LiCoO ₂ , cobalt carbonate, cobalt sulfate, cobalt nitrate, cobalt sulfite, cobalt perchlorate, cobalt thiocyanate, cobalt oxalate, cobalt acetate, cobalt fluoride, cobalt chloride, Cobalt bromide, cobalt iodide, hexaamminecobalt complex salt (as salts, sulfuric acid, nitric acid, perchloric acid, thiocyanic acid, oxalic acid, acetic acid, fluorine, chlorine, bromine, iodine), nickel oxide,
Nickel hydroxide, nickel carbonate, nickel sulfate, nickel nitrate, nickel fluoride, nickel chloride, nickel bromide,
Nickel iodide, nickel formate, nickel acetate, nickel acetylacetonate, copper oxide (1, 2 valent), copper hydroxide, copper sulfate, copper nitrate, copper phosphate, copper fluoride, copper chloride, ammonium chloride copper, bromide Copper, copper iodide, copper formate, copper acetate, copper oxalate, copper citrate, niobium oxychloride, niobium pentachloride, niobium pentaiodide, niobium monoxide, niobium dioxide, niobium trioxide, niobium pentoxide, niobium oxalate, Niobium methoxide, niobium ethoxide, niobium propoxoxide, niobium butoxide, lithium niobate, MoO ₃ , MoO ₂ , LiMo ₂
O ₄ , molybdenum pentachloride, ammonium molybdate,
Examples thereof include lithium molybdate, ammonium molybdophosphate, molybdenum acetylacetonate oxide, WO ₃ , tungstic acid, ammonium tungstate, and ammonium tungstophosphate.

Particularly preferred transition metal compounds used in the present invention include TiO ₂ , lithium titanium oxalate and VO _d.
(D = 2-2.5), VO _d lithium compound, ammonium metavanadate, MnO ₂ , Mn ₂ O ₃ , manganese hydroxide, manganese carbonate, manganese nitrate, manganese ammonium sulfate, manganese acetate, manganese oxalate, citric acid Manganese, iron oxide (2,3 valence), triiron tetraoxide, iron hydroxide (2,3 valence), iron acetate (2,3 valence), iron citrate (2,3 valence)
Trivalent), ammonium iron citrate (2,3 valent), iron oxalate (2,3 valent), ammonium iron oxalate (2,3 valent), Co
₂ O ₃ , Co ₃ O ₄ , LiCoO ₂ , cobalt carbonate, cobalt oxalate, cobalt acetate, nickel oxide, nickel hydroxide, nickel carbonate, nickel sulfate, nickel nitrate, nickel acetate, copper oxide (1, 2 valent), water Copper oxide, copper acetate, copper oxalate, copper citrate, MoO ₃ , MoO ₂ , LiMo ₂ O ₄ ,
WO ₃ can be mentioned. Particularly preferred combinations of the lithium compound and the transition metal compound used in the present invention are lithium hydroxide, lithium carbonate and VO _d (d = 2-2.
5), lithium compounds of VO _d , ammonium metavanadate, MnO ₂ , Mn ₂ O ₃ , manganese hydroxide, manganese carbonate, manganese nitrate, iron oxide (2,3 valent), ferric tetraoxide, iron hydroxide (2 (Trivalent) iron acetate (2,3 valent), iron citrate (2,3 valent), ammonium iron citrate (2,3 valent)
Valence), iron oxalate (2,3 valency), ammonium iron oxalate (2,
Trivalent), Co ₂ O ₃ , Co ₃ O ₄ , LiCoO ₂ , cobalt carbonate, cobalt sulfate, cobalt nitrate, nickel oxide, nickel hydroxide, nickel carbonate, nickel sulfate, nickel nitrate, nickel acetate, copper oxide (1, Divalent), MoO ₃ ,
Examples include MoO ₂ , LiMo ₂ O ₄ , and WO ₃ .

The firing used in the present invention can be performed in air or in an inert gas (nitrogen gas, argon gas).
The firing temperature may be a temperature at which the compound used in the invention is decomposed and melted, and for example, 250 to 2000 ° C is preferable, and 350 to 1500 ° C is particularly preferable. The chemical formula of the compound obtained by firing by the method of the present invention was calculated by an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method, and as a simple method from the weight difference between the powder before and after firing. The oxide used in the present invention may be crystalline or amorphous,
Crystalline compounds are preferred. Amorphous here is said to be amorphous, and represents a solid state in which a crystal lattice (periodic arrangement of atoms) is scarcely observed.
A solid state that does not give a clear X-ray diffraction image even if there are some periodic arrangement of atoms. Both the positive electrode active material of transition metal oxide and the negative electrode active material of transition metal oxide used in the present invention are considered to be compounds capable of inserting and extracting lithium ions.

The negative electrode active material that can be used in combination with the present invention includes lithium metal and lithium alloys (Al, A
1-Mn (U.S. Pat. No. 4,820,599), Al-
It absorbs Mg (JP-A-57-98977), Al-Sn (JP-A-63-6,742), Al-In, Al-Cd (JP-A-1-144,573), lithium ion or lithium metal. A calcined carbonaceous compound that can be released (for example, JP-A-58-209,864 and 61-214,4).
17, 62-88, 269, 62-216, 17
0, same 63-13, 282, same 63-24, 555, same 63-121, 247, same 63-121, 257, same 6
3-155, 568, 63-276, 873, 63
-314,821, JP-A-1-204,361, 1-
221, 859 and 1-274, 360).

A conductive agent, a binder, a filler and the like can be added to the electrode mixture. The conductive agent may be any electronically conductive material that does not undergo a chemical change in the constructed battery. Usually, natural graphite (scaly graphite, scaly graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber and metal (copper, nickel, aluminum, silver (JP-A-63-1).
48, 554), powders, metal fibers, or polyphenylene derivatives (Japanese Patent Laid-Open No. 59-20971) can be included as one kind or a mixture thereof. The amount of the conductive material added is not particularly limited, but is preferably 1 to 50% by weight, and particularly preferably 2 to 30% by weight. The binder is usually starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, tetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene. Monomers (EPDM), sulfonated EPDM, styrene-butadiene rubber, polybutadiene, fluororubber, polysaccharides such as polyethylene oxide, thermoplastic resins, polymers having rubber elasticity and the like are used alone or as a mixture thereof. For example, in the case of a compound containing a functional group that reacts with lithium, such as a polysaccharide, it is preferable to add a compound such as an isocyanate group to deactivate the functional group. The amount of the binder added is not particularly limited, but is preferably 1 to 50% by weight, and particularly 2 to 30%.
Weight percent is preferred. As the filler, any fibrous material that does not cause a chemical change in the constructed battery can be used. Generally, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used.

As the electrolyte, organic solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1 , 3-dioxolane,
Formamide, dimethylformamide, dioxolane,
Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester (JP-A-60-23, 97)
3), trimethoxymethane (JP-A-61-4,17)
0), a dioxolane derivative (JP-A-62-15,77).
1, 62-222, 372, 62-108, 47
4), sulfolane (JP-A-62-31959), 3-
Methyl-2-oxazolidinone (JP-A-62-44,9
61), a propylene carbonate derivative (JP-A-62-1
290,069, 62-290,071), tetrahydrofuran derivative (JP-A-63-63,872), ethyl ether (JP-A-63-62,166), 1,3-propane sultone (JP-A-63-62). 102, 173) a mixture of at least one aprotic organic solvent and a lithium salt soluble in the solvent, for example, ClO _{4
^{-, BF 6 -, PF 6}} -, CF 3 SO 3 -, CF 3 CO
^{_{2 -, AsF 6 -, SbF}} 6 -, B 10 Cl 10 - ( JP 57-74,974), (1,2-dimethoxyethane)
₂ ClO ₄ ^- (JP 57-74,977), lower aliphatic carboxylic acid salt (JP-60-41,773), AlC
l ₄ ⁻ , Cl ⁻ , Br ⁻ , I ⁻ (JP-A-60-247,
265), a chloroborane compound (JP-A 61-165,
957), tetraphenyl boric acid (JP-A-61-214,3).
76) and the like. Above all,
LiCF ₃ SO was added to a mixed solution of propylene carbonate and 1,2-dimethoxyethane or diethyl carbonate.
_An electrolyte containing ₃ , LiClO ₄ , LiBF ₄ or LiPF ₆ is typical. The addition amount of these electrolytes is not particularly limited, but a necessary amount can be used depending on the amounts of the positive electrode active material and the negative electrode active material. The concentration of the supporting electrolyte is not particularly limited, but is 0.2 to 3 per liter of the electrolyte.
Molar is preferred.

In addition to the electrolytic solution, the following solid electrolytes can be used. Solid electrolytes are classified into inorganic solid electrolytes and organic solid electrolytes. Li-nitrides, halides, oxyacid salts, and the like are well known as inorganic solid electrolytes. Among them, Li ₃ N, LiI, Li ₅ N
_{I 2, Li 3 N-LiI} -LiOH, LiSiO 4, L
iSiO ₄ -LiI-LiOH (JP-A-49-81,8)
_{99), xLi 3 PO 4 -} (1-x) Li 4 SiO
₄ (JP-A-58-60,866), Li ₂ SiS ₃ (JP-A-60-501,731), phosphorus sulfide compound (JP-A-62-82,665) and the like are effective. In the organic solid electrolyte, the polyethylene oxide derivative is a polymer containing the derivative (JP-A-63-135,447), a polypropylene oxide derivative or a polymer containing the derivative, a polymer containing an ion dissociating group (JP-A-62-254,30).
2, ibid. 62-254, 303, ibid. 63-193, 95
4), a mixture of a polymer containing an ionic dissociative group and the above aprotic electrolytic solution (US Pat. Nos. 4,792,504 and 4,830,939, JP-A-62-22,375 and 6).
2-22, 376, 63-2, 375, 63-2
2,776, JP-A-1-95,117) and phosphoric acid ester polymers (JP-A-61-256,573) are effective. Furthermore, there is also a method of adding polyacrylonitrile to the electrolytic solution (JP-A-62-278,774). Further, a method of using an inorganic and organic solid electrolyte in combination (Japanese Patent Laid-Open No. 60-1,
768) is also known.

The separator has a high ion permeability,
An insulating thin film having a predetermined mechanical strength. A sheet or non-woven fabric made of an olefin polymer such as polypropylene or glass fiber or polyethylene is used because of its resistance to organic solvents and hydrophobicity. The pore size of the separator is in the range generally used for batteries. For example, 0.01 to 10 μm is used.
The thickness of the separator is in the range generally used for batteries. For example, 5 to 300 μm is used.

It is also known to add the following compounds to the electrolyte for the purpose of improving discharge and charge / discharge characteristics. For example, pyridine (JP-A-49-108,52)
5), triethylphosphite (JP-A-47-4,3)
76), triethanolamine (JP-A-52-72,4)
25), cyclic ethers (JP-A-57-152,68)
4), ethylenediamine (JP-A-58-87,77)
7), n-glyme (JP-A-58-87,778), hexaphosphoric acid triamide (JP-A-58-87,779),
Nitrobenzene derivative (JP-A-58-214, 28)
1), sulfur (JP-A-59-8,280), quinoneimine dye (JP-A-59-68,184), N-substituted oxazolidinone and N, N'-substituted imidazolidinone (JP-A-5-280).
9-154,778), ethylene glycol dialkyl ether (JP-A-59-205,167), quaternary ammonium salt (JP-A-60-30,065), polyethylene glycol (JP-A-60-41,773), Pyrrole (JP-A 60-79,677), 2-methoxyethanol (JP-A 60-89,075), AlCl ₃ (JP-A 61-88,466), monomer of conductive polymer electrode active material (special (Kaisho 61-161,673), triethylenephosphonamide (JP-A-61-208,758), trialkylphosphine (JP-A-62-80,976), morpholine (JP-A-62-80,977). , An aryl compound having a carbonyl group (JP-A-62-86,67)
3), hexamethylphosphoric triamide and 4-alkylmorpholine (JP 62-217,575), bicyclic tertiary amine (JP 62-217,578), oil (JP 62 -287,580), a quaternary phosphonium salt (JP-A-63-121268), a tertiary sulfonium salt (JP-A-63-121269), and the like.

Further, in order to make the electrolytic solution nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolytic solution. (JP-A-48-36,
632), and carbon dioxide may be included in the electrolytic solution so as to be suitable for high temperature storage. (JP-A-59-
134, 567) Further, the positive electrode active material or the negative electrode active material may contain an electrolytic solution or an electrolyte. For example, the ion conductive polymer or nitromethane (Japanese Patent Laid-Open No. 48-
36, 633) and addition of an electrolytic solution (JP-A-57-124,
870) is known. Further, the surface of the positive electrode active material can be modified. For example, the surface of the metal oxide is treated with an esterifying agent (JP-A-55-163,779) or a chelating agent (JP-A-55-163,78).
0), a conductive polymer (JP-A-58-163,188, JP-A-59-14,274), polyethylene oxide and the like (JP-A-60-97,561). Also, the surface of the negative electrode active material can be modified. For example, an ion conductive polymer or a polyacetylene layer is provided (Japanese Patent Laid-Open No. 58-111,276), LiCl
(JP-A-58-142,771), ethylene carbonate (JP-A-59-31,573), and the like.

[0025]

The present invention will be described in more detail with reference to the following examples, but the invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

Example 1 Negative electrode active materials a, b and c were synthesized by the following method. a. Mixing Li ₂ CO ₃ , CoO, and V ₂ O ₅ ,
It was calcined in air at 750 ° C. b. LiOH.H ₂ O, CoO and V ₂ O ₅ were mixed and fired at 650 ° C. in air. c. First, CoO and V ₂ O ₅ are mixed and fired at 800 ° C. in air, and then Li ₂ CO ₃ and V ₂ O ₅ are added to the fired product.
Were mixed and fired at 650 ° C. in air. The above negative electrode active materials have different synthetic methods but all have L composition.
It was iCoVO ₄ . d. Li ₂ CO ₃ , NH ₄ CO ₃ and NiCO ₃・ 2
Ni (OH) ₂ is mixed and baked in air at 800 ° C to obtain L
i _0.75 VNiO ₄ was obtained. e. LiOH, NH ₄ VO ₃ and (NH ₄ ) ₂ TiO
(C ₂ H ₄₎ a mixture of the ₂ · 2H ₂ O, to give a LiVTiO ₄ was calcined at 800 ° C. in air.

87 parts by weight of each of the above negative electrode active materials and acetylene black and graphite as a conductive agent,
After mixing 5 parts by weight and 5 parts by weight, and further adding 3 parts by weight of N-methylpyrrolidone solution of polyvinylidene fluoride in solid content as a binder and kneading, the current collector of the present invention (foil-like ) Was applied to both sides. The above coated material was dried and compression-molded with a roller press to prepare a strip-shaped negative electrode sheet (1). The thickness of the negative electrode sheet after compression molding is 150 μm.
Met. Furthermore, after a lead plate was spot-welded to the end of the negative electrode sheet, heat treatment was performed for 2 hours at various temperatures in dry air having a dew point of -40 ° C or less. Table 1 shows the combination of the active material of the present invention, the current collector and the heat treatment conditions and the evaluation results.

87 parts by weight of LiCoO ₂ as a positive electrode active material, 4 parts by weight and 6 parts by weight of acetylene black and graphite as conductive agents, respectively, and 3 parts by weight of polyvinylidene fluoride as a binder were mixed. The slurry which was added and kneaded in the form of a methylpyrrolidone solution was applied to both sides of an aluminum foil current collector having a thickness of 20 μm. The coated material was dried and compression-molded by a roller press to prepare a positive electrode sheet (2) having a thickness of 250 μm. After a lead plate was spot-welded to the end of the positive electrode sheet, heat treatment was performed at 250 ° C. for 2 hours in dry air having a dew point of −40 ° C. or less.

The negative electrode (1), the microporous polypropylene separator (3), the positive electrode (2) and the separator (3) were laminated in this order and spirally wound. The wound body was housed in a bottomed cylindrical battery can (4) made of iron and plated with nickel and also serving as a negative electrode terminal. Furthermore, 1 as an electrolyte
mol / liter · LiBF ₄ a (equal volume mixture of propylene carbonate and 1,2-dimethoxyethane) was injected into the battery can. A battery lid (5) having a positive electrode terminal was caulked via a gasket (6) to produce a cylindrical battery. The positive electrode terminal (5) was connected to the positive electrode sheet (2), and the battery can (4) was connected to the negative electrode sheet (1) by a lead terminal in advance. FIG. 1 shows a cross section of the cylindrical battery. In addition, 7 is a safety valve.

The charge and discharge characteristics of the battery prepared by the above method were evaluated. First, constant-current charging / discharging was repeated at 200 ° C. at 22 ° C. between a charge end voltage of 4.1 V and a discharge end voltage of 1.8 V. The number of repetitions (cycle characteristics) when the discharge capacity reached 60% of the initial discharge capacity was evaluated as charge / discharge characteristics. The results, initial discharge capacity and operating voltage are shown in Table 1.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

As is clear from the results shown in Table 1, the battery using the negative electrode current collector of the present invention made of copper, nickel, titanium or their alloys or stainless steel has excellent charge / discharge cycle characteristics. On the other hand, the charge / discharge cycle characteristics of the battery of Comparative Example, in which aluminum is used as the negative electrode current collector, the heat treatment is less than 100 ° C., or the thickness is more than 200 μ, are remarkably inferior.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a general cylindrical battery. Fuji Photo Film Co., Ltd.

[Explanation of symbols]

 1. Negative electrode 2. Positive electrode 3. Separator 4. Battery can 5. Battery cover 6. Gasket 7. safety valve

Claims (9)

[Claims] 1. A secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein at least one of the negative electrode active materials contained in the negative electrode comprises a metal oxide, and the current collector of the negative electrode has a thickness of 5 to 200.
A non-aqueous secondary battery characterized by comprising μ of copper, nickel, titanium or an alloy thereof. 2. The secondary battery according to claim 1, wherein the current collector of the negative electrode is a metal foil having a thickness of 5 to 100 μm. 3. The secondary battery according to claim 1, wherein at least one kind of the negative electrode active material is a lithium-containing transition metal oxide obtained by firing. 4. At least one of the negative electrode active materials comprises Li _x
Co _y V _1-y O _z or Li _x Ni _y V _1-y O _z (where x = 0.4 to 3, y = 0 to 1, z = 1.2 to 5.5)
The secondary battery according to claim 1, wherein the secondary battery is 5. A secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein at least one of the negative electrode active materials contained in the negative electrode comprises a metal oxide, and the current collector of the negative electrode comprises copper, nickel,
A non-aqueous secondary battery comprising titanium or an alloy thereof or stainless steel, which is heat-treated at a temperature of 100 ° C to 500 ° C. 6. The secondary battery according to claim 5, wherein the stainless steel according to claim 5 is a steel containing 1 to 6% by weight of molybdenum and 15 to 20% by weight of chromium. 7. The secondary battery according to claim 5, wherein the current collector of the negative electrode is a metal foil having a thickness of 5 to 100 μm. 8. The secondary battery according to claim 5, wherein at least one kind of the negative electrode active material is a lithium-containing transition metal oxide obtained by firing. 9. At least one of the negative electrode active materials comprises Li _x
Co _y V _1-y O _z or Li _x Ni _y V _1-y O _z (where x = 0.4 to 3, y = 0 to 1, z = 1.2 to 5.5)
The secondary battery according to claim 5, wherein