Toyota Jidosha Kabushiki Kaisha

Hiroshi Onizuka

Tomohiro Nakano

Hiroki Nagai

Takashi Harayama

Mitsuru Sakano

Takumi Tamaki

Kyoko Kikuchi

The present invention provides a nonaqueous electrolyte secondary battery configured such that a positive electrode, a negative electrode, and a nonaqueous electrolyte are accommodated in a battery case. The battery includes lithium bis(oxalato)borate (LiBOB) at least at the time of assembly of the battery. The negative electrode includes a film derived from the LiBOB and containing a boron atom (B) and a carbonate ion (CO). A ratio (mc/mb) of a molar content mc of the carbonate ion to a molar content mb of the boron atom is 4.89 or less. In a preferred aspect, when a molar content A of the LiBOB is A (mmol) and a remaining space volume in the battery case is V (cm) at the time of the assembly, a ratio A/V is 0.053 or less.

Nonaqueous electrolyte secondary battery

A lithium ion battery has a flat wound electrode assembly, a nonaqueous electrolyte, and a battery case. The nonaqueous electrolyte contains an electrically insulating inorganic aggregate and is formed of an impregnating electrolyte impregnated into the flat wound electrode assembly and a surplus electrolyte not impregnated into the flat wound electrode assembly. Letting the flat wound electrode assembly be divided into a planar region where the electrode surfaces are planar surfaces and a lower wound curved region which is positioned vertically downward from the planar region and where the electrode surfaces are curved, a boundary plane that includes the boundary between the planar region and the lower wound curved region, the inorganic aggregate amount Mincluded in a space which is below the boundary plane and the inorganic aggregate amount Mincluded in the impregnating electrolyte within the flat wound electrode assembly satisfy the relationship M&#x3e;M.

The present invention provides a negative electrode active material which can prevent reduction in battery capacity by suppressing reaction of an electrolyte solution at the surface of the negative electrode active material as well as can reduce resistance resulting from the formation of a film. A negative electrode active materialfor a lithium ion secondary battery comprises a carbon materialcapable of reversibly storing and releasing lithium, an amorphous carbon membranecoating the surface of the carbon material and a filmcontaining a phosphate compound and coating the surface of the amorphous carbon membrane.

Negative electrode active material for lithium ion secondary battery

This invention provides a method for producing a non-aqueous electrolyte secondary battery. The method comprises constructing a battery cell that comprises a positive electrode comprising a positive electrode active material, a negative electrode comprising a negative electrode active material, and a non-aqueous electrolyte solution comprising a non-aqueous solvent and an oxalatoborate-based compound. The method further comprises charging the battery cell to form on the negative electrode a layer that is derived from the oxalatoborate-based compound and comprises boron and oxalate ions. The method further comprises carrying out a modification treatment to increase the ratio of number of moles mof boron to number of moles mof oxalate ions in the layer.

Non-aqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery according to the present invention includes a positive electrode, a negative electrode, and a non-aqueous electrolyte solution. The negative electrode includes a coating derived from lithium bis(oxalate)borate. The coating derived from lithium bis(oxalate)borate includes a coating containing boron element and a coating containing oxalate ion. A ratio of the boron element contained in the coating derived from lithium bis(oxalate)borate to the oxalate ion is equal to or more than 5. Accordingly, it is possible to provide a non-aqueous electrolyte secondary battery capable of reliably obtaining the effect due to the formation of a coating.

Non-aqueous electrolyte secondary battery and manufacturing method thereof

A lithium secondary batteryis configured such that an electrode body, in which a cathode and an anode are stacked via a separator impregnated with an electrolyte, is housed in a battery casehaving a substantially cylindrical square shape and that an openingof the caseis blocked by a lidFurther, the lidis provided with a cathode terminaland an anode terminaland such terminals are respectively connected, inside the battery caseto an internal cathode collection terminaland an internal anode collection terminalA non-aqueous electrolyte used for the lithium secondary batterycontains, as a specific compound, for example, LiBOB, and an initial content of such specific compound relative to a capacitance of the anode is 0.04 to 0.5 [(mol/kg)/(mF/cm)].

Non-aqueous electrolyte secondary battery, and manufacturing method thereof

The manufacturing method of the invention includes the steps of: providing a positive electrode and a negative electrode (S), a sodium ingredient being included in either the positive electrode or the negative electrode; producing an electrode assembly from the provided positive electrode and negative electrode (S); producing a battery assembly in which the electrode assembly is housed in a battery case (S); injecting a nonaqueous electrolyte solution into the battery case (S), the nonaqueous electrolyte solution including at least lithium bis(oxalato)borate, a fluorophosphate compound, a carbonate solvent and an ether solvent, and the amount of ether solvent included in the nonaqueous electrolyte solution being less than 10 vol % when the amount of nonaqueous solvent included in the nonaqueous electrolyte solution is set to 100 vol %; and charging and discharging the battery assembly (S).

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Toyota, Japan

Hiroshi Onizuka