Sanyo Electric Co., Ltd.

Kouichi Satoh

Ikuo Yonezu

Naoya Nakanishi

Toshiyuki Nohma

Koji Nishio

Kazuyasu Fujiwara

Atsuhiro Funahashi

Yoshito Chikano

Kazunari Ohkita

Shin Fujitani

Hiroyuki Akita

Kouichi Nishimura

Yasuhiro Yamauchi

Hideki Kitao

Noriyuki Miyazaki

Noboru Nakano

A battery including an electrode unit which is an electricity generating element housed in a battery can, in which the electricity can be taken out of the can via a pair of negative and positive electrode terminals which are exposed outside the can, and one of the negative and positive electrode terminals has a coating layer formed on a surface thereof that is the same material as the material of which the other of the negative and positive electrode terminals is made.

Battery

A battery including an electrode unit housed in a battery can and which generates electricity which can be taken out of the battery via a pair of negative and positive electrode terminals, wherein a terminal assembly is installed in the battery, a current collector plate is connected to an edge of an electrode of the electrode unit for connecting the electrode unit to the terminal assembly, and one or more than one connecting piece which is protrusively formed on a surface of the current collector plate is welded and secured to a base portion of the terminal assembly.

Battery with current collector plate welded to electrode terminal assembly

A secondary cell comprises an electrode unit housed in a cell can comprising a cylinder having a bottom and a closed opening, and a current collector plateis provided at one end of the electrode unit. The current collector platehas a plurality of protrusionsextending radially thereof and joined to an edge of the electrode unit. The surface of the current collector plateto be joined to the bottom wall of the cylinder has a flat region R extending on a predetermined closed-loop track on the surface, and the portions of the current collector plateand the cylinder to be joined are subjected along the flat region R to laser welding from outside the cylinder.

Secondary cell

A non-aqueous electrolyte secondary battery is provided with a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein positive electrode active material is a mixture of lithium-manganese composite oxide having spinel structure represented by a general formula LiMnO(wherein a relationship 0&#x2266;z&#x2266;0.2 is satisfied) and lithium-transition metal composite oxide represented by the general formula LiNiCoMnO(wherein the relationships 0.5&#x3c;x+y&#x3c;1.0 and 0.1&#x3c;y&#x3c;0.6 are satisfied), and negative electrode active material is graphite coated with low crystalline carbon where whole or a part of a surface of first graphite material as a substrate is coated with second carbon material which is lower in crystallinity compared with the first graphite material.

Non-aqueous electrolyte secondary battery

A nonaqueous electrolyte secondary cell comprises a rolled-up electrode unitcomposed of a positive electrode, a negative electrodeand a separatorinterposed therebetween, and a negative electrode current collector plateand a positive electrode current collector platejoined to the respective ends of the electrode unit. The negative electrode collector plateis joined to an edge of the negative electrodeprojecting at one of the opposite ends of the electrode unit. The collector platehas a two-layer structure comprising a copper layermade of copper or an alloy consisting predominantly of copper, and a metal layer made of a metal not forming an intermetallic compound with lithium and having a lower laser beam reflectivity than copper or an alloy consisting predominantly of the metal. The collector platehas its copper layercontacted with the edge of the negative electrodeand welded thereto with a laser beam. This improves the weldability of the collector plateto the rolled-up electrode unitto achieve a high current collecting efficiency.

Process for fabricating nonaqueous electrolyte secondary cells

A battery module has a plurality of electrically connected unit cells fixed in a container. A buffer member is provided at the void between the inner wall of the container and the unit cell. By virtue of the buffer member in the battery module formed of a heat conductive elastic body, the requirement of vibration resistance can be met by the buffer member while the heat generated by the unit cell can be easily discharged via the buffer member. Thus, a battery module suppressed in degradation of the performance of the unit cell caused by heat can be provided.

Battery module and container for battery module

Nonaqueous electrolyte secondary cells

Used as the positive electrode active substance of a lithium ion secondary cell is a mixture of a lithium-nickel-cobalt-manganese composite oxide represented by the formula LiNi CO Mn O wherein 0.5<x&plus;y<1.0 and 0.1<y<0.6 and a lithium-manganese composite oxide represented by the formula Li Mn O wherein 0&lE;z&lE;0.2. The substance used gives outstanding power characteristics to the cell.

A nonaqueous electrolyte secondary cell includes a rolled-up electrode unit composed of a positive electrode, a negative electrode and a separator interposed therebetween, and a negative electrode current collector plate and a positive electrode current collector plate joined to the respective ends of the electrode unit. The collector plate has a two-layer structure comprising a copper layer made of copper or an alloy consisting predominantly of copper, and a metal layer made of a metal not forming an intermetallic compound with lithium and having a lower laser beam reflectivity than copper or an alloy consisting predominantly of the metal. The collector plate has its copper layer contacted with an edge of the negative electrode projecting at one of the opposite ends of the electrode unit and welded thereto with a laser beam.

Nonaqueous electrolyte secondary cells and process for fabricating same

A nonaqueous electrolyte secondary cell includes a rolled-up electrode unit composed of a positive electrode, a negative electrode and a separator interposed therebetween, and a negative electrode current collector plate and a positive electrode current collector plate joined to the respective ends of the electrode unit. The negative electrode collector plate is joined to an edge of the negative electrode projecting at one of the opposite ends of the electrode unit. The collector plate has a two-layer structure of a copper layer made of copper or an alloy consisting predominantly of copper, and a metal layer made of a metal not forming an intermetallic compound with lithium and having a lower laser beam reflectivity than copper or an alloy consisting predominantly of the metal. The collector plate has its copper layer contacted with the edge of the negative electrode and welded thereto with a laser beam.

In a nonaqueous electrolyte secondary cell comprising a rolled-up electrode unit encased in a cell can a striplike current collector forming an electrode has an edge projecting from at least one of opposite ends of the electrode unit. A current collecting plate is joined to the current collector edge A plurality of circular-arc protrusions projecting in a circular-arc cross section and a plurality of slit pieces are formed radially on the current collecting plate and opposed to the current collector edge The collecting plate is welded to the current collector edge with the protrusions and the slit pieces biting into the current collector edge whereby high current collecting performance is available.

A secondary cell comprises a gastight can having a cylinder and a lid fixed to an opening portion of the cylinder, and a secondary cell element accommodated in the can . The lid is fixedly provided with a gas vent closure in the form of a disk and having a diaphragm openable upon the internal pressure of the can exceeding a predetermined value. The gas vent closure has an outer peripheral portion welded to an opening edge defining a through bore formed in the lid . The lid is formed in a front surface thereof with a circumferential groove surrounding the welded portion of the gas vent closure , and a diminished portion is provided between the groove and the welded portion for reducing the sectional area of a heat flow path for the heat of welding to pass therethrough. The lid thus constructed makes it possible to weld the vent closure to the lid free of defects such as pinholes or cracks.

In the nonaqueous secondary battery of this invention, a positive electrode includes, as an active material, a composite oxide represented by a composition formula, Li Mn Ni M O , wherein M is at least one element selected from the group consisting of B, Mg, Al, Ti, V, Fe, Co, Cu, Zn, Ga, Y, Zr, Nb, Mo and In; 1.20&lE;x&lE;1.80; y&gE;0.10; z&gE;0; y&plus;z&lE;1.90; and 3.70&lE;q&lE;4.30, in a discharge state during fabrication of the nonaqueous secondary battery. As a result, the nonaqueous secondary battery can exhibit good charge-discharge cycle performance and can be fabricated at low cost.

Nonaqueous secondary battery

For use in lithium secondary cells, a positive electrode terminal and a negative electrode terminal are given an enhanced mechanical strength to improve the reliability of electrical connection between the cell and an external circuit, while the formation of oxide film on these terminals is inhibited to suppress the discharge voltage drop of the cell. To give these advantages to the lithium secondary cell embodying the invention, the positive electrode terminal is formed from an aluminum alloy containing magnesium and silicon in a combined amount of at least 1.0 wt. % as additive elements, and the negative electrode terminal is formed by plating a substrate of oxygen-free copper with nickel.

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Kobe, Japan

Kouichi Satoh