Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Electrode
Reexamination Certificate
2001-02-02
2004-05-11
Ruthkosky, Mark (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Electrode
C429S209000, C429S247000
Reexamination Certificate
active
06733925
ABSTRACT:
FIELD OF THE INVENTION
The present application relates to a non-aqueous electrolytic solution secondary battery, and in particular relates to a non-aqueous electrolytic solution secondary battery where a winding group, where a positive electrode having a positive electrode collector applied with a positive electrode mixture including a positive electrode active material from/in which lithium-ions can be released/occluded through charging/discharging and a negative electrode having a negative electrode collector applied with a negative electrode mixture including a negative electrode active material in/from which lithium-ions can be occluded/released through discharging/charging are wound though a separator, is infiltrated into non-aqueous electrolytic solution where a lithium salt is dissolved into organic solvent, and is accommodated into a battery container.
DESCRIPTION OF THE RELATED ART
Conventionally, in a lithium secondary battery using a metallic lithium or a lithium alloy for a negative electrode, there has been a drawback in that internal shorts between a positive electrode and the negative electrode occur since a dendritic lithium deposits on the negative electrode at the time of charging. In order to solve this problem, a lithium-ion secondary battery using a lithium transition metallic complex oxide such as lithium cobaltate (LiCoO
2
), lithium nickelate (LiNiO
2
), lithium manganate (LiMn
2
O
4
) or the like as a positive electrode active material, and a carbon material as a negative electrode active material, has been developed recently. Among the lithium transition metallic complex oxides, a complex oxide using manganese has an advantage over a complex oxide using cobalt in cost performance due to its abundant quantity of natural resources, and it also has an advantage in safety.
Because the lithium-ion secondary battery has high energy density as its merit, attention to the battery is being paid not only as a power supply source for portable equipment mainly such as a VTR camera, a note type computer, a portable telephone and the like, but also as a power supply source mounted for a vehicle. Namely, in order to cope with the environmental problems in the automotive industry, development of an electric vehicle (hereinafter called “EV”) whose power source is confined entirely to a battery so that there is no gas exhausting and of a hybrid electric vehicle (hereinafter called “HEV”) where both an internal combustion engine and a battery are used as its power source, has been accelerated, and some of them have reached a practical stage.
The lithium-ion secondary batteries can be classified into cylindrical shape ones and rectangular shape ones according to their outer shapes. The cylindrical shape ones are popular at the present time. The interior of the cylindrical lithium-ion secondary battery has a winding type structure where each of the positive electrode and the negative electrode comprises a metallic foil applied with an active material and is formed in a strip shape, and to form a winding group the positive and negative electrodes are wound spirally through a separator so as not to directly come in contact with each other. The winding group is accommodated in a cylindrical battery can which is a battery container, and after the battery container is filled with non-aqueous electrolytic solution, it is sealed and then by initial charging, the cylindrical battery is given a function as a secondary battery.
The battery for the power supply source of the EV/HEV is required to have high power and high-energy characteristics. In order to meet the requirement, various contrivances are needed not only to the winding group but also to the non-aqueous electrolytic solution. As a contrivance example for the non-aqueous electrolytic solution, Applicant disclosed a technique, in a Japanese patent application, serial number 11-119359, filed on Apr. 27, 1999, for setting the proportion of organic solvent to dissolve a lithium salt. As stated in the application, since generating elements such as the positive
egative electrodes and the like which comprise the winding group deteriorate extremely subject to the influence of moisture or water content, the non-aqueous electrolytic solution secondary battery adopts a hermetically sealed structure in which an opening portion of the battery container is sealed by laser-welding or the like so that the generating elements can be shut off from the atmosphere.
When the complex oxide expressed by a chemical formula Li
x
Mn
y
O
2
(0.4≦x≦1.35, 0.65≦y≦1.0) is used as the positive electrode active material, there were drawbacks in that a charging/discharging cycle life characteristic of the lithium-ion secondary battery becomes short and a power (output) characteristic thereof becomes lowered. Particularly, when the battery is used at a high temperature of 50° C. or more, there are disadvantages in that the power and cycle life characteristics deteriorate since the manganese elutes from the positive electrode and the eluted manganese forms a nonconductive (inert) coating on the surface of the negative electrode.
Further, in order to assist acceleration force of motor drive in the HEV, the charging and the discharging accompanied with a large electrical current are repeated during a short time. For this reason, in the non-aqueous electrolytic solution secondary battery for the HEV, a new battery characteristic of high outputting that has never been needed hitherto is required. A high output can be gained when the discharging is carried out at a small current in the conventional lithium-ion secondary battery, however, it had a drawback in that the output goes down remarkably when the discharging is carried out at a large current. It is considered for this reason that, since the movement of lithium-ions can not follow the rapid flowing of electrons, it causes large concentration gradient in the separator and/or electrodes. This brings about an increase in an internal resistance and results in a drop in the output.
As stated above, with progress in the development of the lithium-ion secondary battery, the battery for the EV/HEV has been required to have a higher power characteristic that the drop in the power is smaller as well as a longer life characteristic in spite of time-lapse or aging. Especially, since the HEV uses both the engine and the motor, the battery that has the high output and that can maintain high input/output characteristics, in other words, the battery where an increase in a direct current internal resistance is small even the time-lapse, is required as the power supply source for the HEV. Accordingly, it is inferred that the spread of the EV/HEV will be accelerated if such a non-aqueous electrolytic solution secondary battery with a higher power and output, and with a longer life, is obtained.
SUMMARY OF THE INVENTION
In view of the above circumstances, a first object of the present invention is to provide a non-aqueous electrolytic solution secondary battery which can prevent a drop in the power. A second object of the present invention is to provide a non-aqueous electrolytic solution secondary battery that has excellent battery characteristics at a high temperature, particularly has a high power characteristic. A third object of the present invention is to provide a non-aqueous electrolytic solution secondary battery that has high input/output characteristics. And a fourth object of the present invention is to provide a non-aqueous electrolytic solution secondary battery that has a long life characteristic.
In order to achieve the above first object, the present invention is a non-aqueous electrolytic solution secondary battery where a winding group, where a positive electrode having a positive electrode collector applied with a positive electrode mixture including a positive electrode active material from/in which lithium-ions can be released/occluded through charging/discharging and a negative electrode having a negative electrode collector applied with a negative electrode mixture including a negative e
Hara Kenji
Higashimoto Koji
Hironaka Kensuke
Iguchi Tomohiro
Koishikawa Yoshimasa
Ruthkosky Mark
Shin-Kobe Electric Machinery Co. Ltd.
LandOfFree
Non-aqueous electrolytic solution secondary battery with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Non-aqueous electrolytic solution secondary battery with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Non-aqueous electrolytic solution secondary battery with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3227607