Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Hisanao Kojima

Hisataka Fujimaki

Shinya Kamada

Katsuyuki Hojo

Norikazu Adachi

Jun Hasegawa

Takahiro Sakurai

Hirohiko Morikawa

Hiroyasu Kado

Hiroaki Ikeda

Tomotaka Hagino

Hiroyuki Kawaki

Hideto Mori

Yasushi Hayashi

Shinya Kuroki

Hiroshi Kawadu

Hirofumi Isoyama

Satoru Suzuki

Provided is a nonaqueous electrolyte secondary battery with better battery performance than in the past, by forming an SEI coat with very little non-uniformity on the surface of the negative electrode active material layer. The invention provides a nonaqueous electrolyte secondary battery in which an electrode assembly including a positive electrode, a separator, and a negative electrode, and a nonaqueous electrolyte are contained in a battery case. In this secondary battery, the nonaqueous electrolyte contains a crown ether that forms a complex with a sodium ion, and the negative electrode includes a negative current collector, a negative electrode active material layer containing a negative electrode active material formed on the surface of the current collector, and a coat including an oxalato complex structure and provided on at least part of the surface of the negative electrode active material layer.

Nonaqueous electrolyte secondary battery, method for producing same and nonaqueous electrolyte

Provided is a method for producing a lithium secondary battery in which localized precipitation of a foreign metal in the negative electrode can be reliably suppressed in a shorter time, regardless of, for instance, electrode type or electrode variability. The production method is a method for producing a secondary battery that includes a positive electrode provided with a positive electrode active material layer, a negative electrode provided with a negative electrode active material layer, and a nonaqueous electrolyte. The method comprises a step of constructing a cell including the positive electrode, the negative electrode and the nonaqueous electrolyte; a micro-charging step of performing charging over one hour or longer, up to 0.01% to 0.5% of the capacity of the constructed cell, in a state of charge such that a positive electrode potential is equal to or higher than an oxidation potential of iron (Fe), and a negative electrode potential is equal to or higher than a reduction potential of iron (Fe), and maintaining the state of charge; and a step of performing an initial conditioning charging.

Method for producing secondary battery

Provided is a method for producing a lithium secondary cell with which the concentrated precipitation of metal impurities at the negative electrode is inhibited and short circuiting is unlikely to occur. The production method includes, assembling together the positive electrode, the separator, and the negative electrode, and then impregnating the assembly with the nonaqueous electrolyte; charging the assembly within 1 min so that a maximum achieved potential of the positive electrode becomes 3.2 V or more with respect to the redox potential of lithium; allowing the assembly to stand for 10 min or less after the charging has ended; and discharging the assembly within 1 min after the standing step.

Method for producing lithium secondary cell

Provided is a method for manufacturing a lithium secondary battery which is capable of preventing a local deposition of a metallic foreign substance at a negative electrode regardless of the type of a positive electrode and in which a short-circuit is less likely to occur. The present manufacturing method comprises: a step of assembling a cell that includes a positive electrode, a negative electrode, and a nonaqueous electrolyte; a micro charging step of performing a micro charge on the assembled cell before performing an initial conditioning charge until a positive electrode potential with respect to a metal lithium (Li) reference electrode exceeds an Me dissolution potential set in advance at which a mixing-anticipated metal species (Me) starts to dissolve; and an Me dissolution potential holding step of holding the positive electrode potential of the cell at or above the Me dissolution potential for a prescribed period of time after the micro charge.

Method for manufacturing lithium secondary battery

A method of testing a secondary battery includes first to fourth steps. At the first step, the secondary battery after manufacture is charged to a first voltage. At the second step, a second voltage lower than the first voltage is set as a target voltage and discharge or charge is performed in a constant-current constant-voltage mode before the secondary battery is left standing. At the third step, the open circuit voltage of the secondary battery is measured before and after the secondary battery is left standing. At the fourth step, it is determined whether the secondary battery is a conforming item or not based on the difference in the open circuit voltage before and after the secondary battery is left standing.

Method of testing secondary battery

A device for protecting a cell is described comprising a cell body arranged in a container which has opening and closing means to open and close the cell body from the exterior atmosphere of the container. The device also has a sensor for sensing an impact to the cell body. When the impact is above a predetermined value, a barrier fluid is sprayed into the interior of the container. The opening and closing means of the container is operated in response to the spraying of the barrier fluid.

Non-aqueous electrolyte lithium secondary cell

An active material for a positive electrode of a secondary cell comprises particles of a metal oxide and a conductive layer formed on the surfaces of individual particles of the metal oxide and made of a carbon powder which has a specific surface area of at least 150 m.sup.2 /g when measured prior to the formation of the conductive layer. The conductive layer covers at least 15% of an apparent surface of the individual particles of the metal oxide and has a thickness ranging from 0.01 .mu.m to 0.3 .mu.m. The active material has a specific surface area of 3.5 m.sup.2 /g to 100 m.sup.2 /g. A method for making the active material is also described along with a positive electrode comprising the active material and a non-aqueous electrolytic secondary cell comprising the positive electrode.

Active materials for a secondary cell, a method for making the same,

A method for preparing an active substance for use in a positive electrode in chemical cells comprising a negative electrode is described. The method comprises preparing a mixed aqueous solution of a water-soluble lithium compound, a water-soluble transition metal compound, and an organic acid selected from the group consisting of organic acids having, in the molecule, at least one carboxyl group and at least one hydroxyl group and organic acids having at least two carboxyl groups, preparing an organic acid complex comprising lithium and a transition metal, and thermally decomposing the complex at temperatures sufficient for the decomposition to obtain the active substance. The complex may be prepared by dehydrating the solution. Alternatively, the complex may be formed by spraying the solution under heating conditions.

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Kariya, Japan

Hisanao Kojima