Japan Storage Battery Co., Ltd.

Gs Yuasa Corporation

Mikio Okada

Hideo Yasuda

Hiroshi Nakahara

Mikito Nagata

Hiroyuki Yumoto

Shinya Kitano

Tetsuya Murai

Hiroshi Mukai

Shigeo Komatsu

Takeshi Hasumi

A nonaqueous secondary electrolytic battery comprising an electricity-generating element formed by spirally winding a laminate of a positive electrode plate, a separating material and a negative electrode plate, and an electrolytic solution with which the separating material, if it is a separator, is impregnated. The electricity-generating element is sealed in a battery case formed by a resin-laminated sheet comprising a metal layer as a barrier layer. Only a pair of lead terminals are drawn to the exterior of the battery case. The resin sheet comprises an oriented resin layer laminated on both surfaces of the metal layer. The inner heat-fused layers are opposed and heat-fused to each other. A molten and solidified resin mass is formed protruding from the inner end of the welded portion toward the inner space of the battery by 0.1 mm or more. Alternatively, the welded portion is formed thinner at the outer end thereof than at the inner end thereof.

Nonaqueous secondary electrolytic battery

In accordance with the non-aqueous electrolyte secondary battery of the invention and the process for the preparation thereof, charging is carried out with a combination of a positive electrode provided with excess lithium and a negative electrode in order to cause lithium to be deposited on the negative electrode. Accordingly, no oxidized surface film is interposed between lithium and the current collector of negative electrode or the negative active material layer as in the case where a metallic lithium foil is laminated on the negative electrode. In this arrangement, a battery having a small internal resistance can be provided. Since the deposition of lithium is conducted in the assembled battery, lithium does not come in contact with air, preventing the formation of a thick ununiform oxidized film on the surface thereof. Thus, the deposition of dendrite can be inhibited, making it possible to inhibit the drop of battery capacity and hence provide a battery having an excellent cycle life performance. Further, lithium can be retained on the negative electrode in an amount excess to the capacity of the positive electrode. Accordingly, even when lithium is lost due to the deposition of dendrite or the reaction with the electrolyte solution, the drop of battery capacity can be inhibited because the negative electrode is provided with excess lithium.

Non-aqueous electrolyte secondary battery and process for the preparation thereof

The non-aqueous electrolyte secondary battery of the present invention comprises, e.g., a positive electrode , a negative electrode , a polymer membrane containing carbon powder or the like, and a separating membrane layer for preventing shortcircuiting. A carbon powder, silicon powder, tin powder or aluminum powder contained in the polymer membrane containing carbon powder or the like absorbs as a lithium-absorbing material metallic lithium powders or metallic lithium dendrite which has been produced from the negative electrode due to charge or discharge and takes no part in charge or discharge. This lithium-absorbing material is less reactive than the metallic lithium powders or metallic lithium dendrite and thus enhances the safety of the battery and controls shortcircuiting between the positive electrode and the negative electrode due to metallic lithium dendrite, making it possible to drastically improve charge and discharge cycle life performance.

Nonaqueous electrolyte secondary cell

In a process for producing an electrode of a nonaqueous electrolyte battery, an electrode and a polymer paste are prepared. The electrode is made of a metal as a current collector and an active material layer thereon. The polymer paste has a polymer dissolved in a solvent soluble in water. The polymer paste is allowed to be held in the electrode. Thereafter, the solvent is extracted from the polymer paste with an aqueous solution containing an alcohol, phosphorous or phosphorous compound.

Process for producing electrode of nonaqueous electrolyte battery

The following aspects (1) to (4) of the present invention can provide an electrode for a nonaqueous electrolyte battery having excellent safety and charged storage properties and good high rate charge-discharge properties. (1) An electrode for nonaqueous electrolyte battery comprising a particulate active material having a porous film formed thereon. (2) An electrode for nonaqueous electrolyte battery comprising an active material having a filler held in pores. (3) An electrode for nonaqueous electrolyte battery comprising an active material which undergoes volumetric expansion and shrinkage during charge-discharge, having a filler held in pores. (4) The electrode for a nonaqueous electrolyte battery according to embodiment (1), wherein said porous film is an ionically-conductive film.

Electrode for nonaqueous electrolyte battery

A nonaqueous polymer cell according to the present invention contains a lithium ion conductive polymer having a porosity in the range of 10% to 80%. In the cell of the present invention, the electrolyte is held not only in the pores of the microporous polymer but also within the polymer itself. Consequently, lithium ions can move not only through the pores of the microporous polymer film but through the polymer itself. The cell of the present invention, which contains a microporous polymer having interconnected pores, shows greatly improved high-rate charge/discharge characteristics especially when the microporous polymer is used in combination with an electrode comprising an active material which expands and contracts upon charge and discharge, because volume changes of the active material cause flows of the electrolyte through the pores of the microporous polymer and the flows carry lithium ions.

Nonaqueous polymer cell

A nonaqueous polymer battery includes a lithium ion conductive polymer having pores, a positive active material, and a carbonaceous negative active material. In the nonaqueous polymer battery, the positive active material is represented by Li.sub.1-x CoO.sub.2 (0.ltoreq.x.ltoreq.1) wherein the molar ratio of the carbon atoms in the negative active material to the cobalt atoms in the positive active material is 7.5 or lower; the positive active material is represented by Li.sub.1-x NiO.sub.2 (0.ltoreq.x.ltoreq.1) wherein the molar ratio of the carbon atoms in the negative active material to the nickel atoms in the positive active material is less than 10; or the positive active material is represented by Li.sub.1-x Ni(Co)O.sub.2 (Li.sub.1-x NiO.sub.2 having not more than 20% of the nickel atoms thereof displaced with cobalt ions; 0.ltoreq.x.ltoreq.1) wherein the ratio of the number of the moles of the carbon atoms present in the negative active material to the total number of the moles of the cobalt atoms and the nickel atoms present in the positive active material is less than 10.

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Kyoto, Japan

Mikio Okada