Metal working – Method of mechanical manufacture – Electrical device making
Patent
1997-07-10
1999-12-14
Nuzzolillo, Maria
Metal working
Method of mechanical manufacture
Electrical device making
42923195, 4292311, 429137, H01M 614
Patent
active
060011394
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a nonaqueous secondary battery in which charge and discharge capacities and cycle characteristics are improved.
BACKGROUND ART
Lithium metals and lithium alloys are used as typical negative electrode materials in nonaqueous secondary batteries, but, when they are used, the lithium metal grows into a dendritic form during charging and discharging to generate a so-called dendrite which becomes a cause of internal short, or the high activity of the dendrite itself poses a possible danger of causing firing and the like.
On the other hand, calcined carbonaceous materials capable of reversely intercalating and deintercalating lithium have been put into practical use. Such carbonaceous material has a relatively small density which poses a disadvantage of having low capacity per volume. Because of this, use of the carbon material by pressing or laminating lithium foil thereto is described in JP-A-5-151995 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), but it cannot resolve the aforementioned problems.
Also, methods in which oxides of Sn, V, Si, B, Zr and the like or composite oxides thereof are used in negative electrode materials have been proposed (JP-A-5-174818, JP-A-6-60867, JP-A-6-275267, JP-A-6-325765, JP-A-6-338324, EP-615296). It is said that negative electrodes of these oxides or composite oxides provide nonaqueous secondary batteries having a large charging capacity of 3 to 3.6 V class when combined with a positive electrode of a certain type of lithium-containing transition metal compound and have markedly high safety, because they hardly generate dendrite within the practical range. However, batteries in which these materials are used have a serious problem in that their charge and discharge characteristics are not sufficient, and their charge and discharge efficiency in initial cycles is particularly low. That is, it is assumed that a portion of lithium molecules intercalated in the negative electrode during the charging step cause a plurality of irreversible side reactions during several initial stage cycles, so that lithium does not move into the positive electrode side during the discharging step, thereby causing capacity loss due to unnecessarily consumed lithium in the positive electrode. In order to compensate for such a capacity loss, it may be possible to intercalate lithium into the negative electrode material in advance in an amount corresponding to the capacity loss, but sufficient effect has not been obtained yet by such means.
The object of the present invention is to obtain a nonaqueous secondary battery which has 1) high charge and discharge capacities and excellent charge and discharge cycle characteristics and 2) a high energy density.
DISCLOSURE OF THE INVENTION
The present invention has been achieved by a cylinder type nonaqueous secondary battery which comprises a positive electrode active material comprising a lithium-containing transition metal oxide, a composite oxide or composite chalcogen negative electrode material capable of intercalating and deintercalating lithium and a nonaqueous electrolyte containing a lithium metal salt, wherein a metal foil mainly comprising lithium is mounted in advance on a coiled group in which a current collector sheet coated with said positive electrode active material (positive electrode sheet), another current collector sheet coated with said negative electrode material (negative electrode sheet) and a separator are coiled in a spiral form.
A nonaqueous secondary battery having a high energy density as an object of the present invention is substantially achieved when a part of or entire portion of the metal foil mainly comprising lithium introduced into the coiled group is finally incorporated into the negative electrode material. As a means for intercalating lithium in the negative electrode material, a method is possible in which lithium is introduced into the negative electrode material by forming a local electrochemical junction in a state that t
REFERENCES:
patent: 4645726 (1987-02-01), Hiratani et al.
patent: 4658498 (1987-04-01), Yamamura et al.
patent: 5069683 (1991-12-01), Fong et al.
patent: 5147739 (1992-09-01), Beard
patent: 5314765 (1994-05-01), Bates
patent: 5387479 (1995-02-01), Koksbang
patent: 5478671 (1995-12-01), Idota
patent: 5595837 (1997-01-01), Olsen et al.
patent: 5616429 (1997-04-01), Klementowski
patent: 5618640 (1997-04-01), Idota et al.
patent: 5721067 (1998-02-01), Jacobs et al.
Asanuma Hiroyuki
Inoue Hiroshi
Ishizuka Hiroshi
Maekawa Yukio
Miyaki Yukio
Fuji Photo Film Co. , Ltd.
Nuzzolillo Maria
O'Malley Jennifer
LandOfFree
Nonaqueous secondary battery having multiple-layered negative el does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Nonaqueous secondary battery having multiple-layered negative el, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nonaqueous secondary battery having multiple-layered negative el will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-858879