Abstract: A cooling unit 20 is provided in the vicinity of a cell 10, and includes a sealed portion 22 formed by sealing a sheet 21. An easy-to-open portion 24 is provided in part of the sealed portion 22, and the easy-to-open portion 24 is opened when the cell 10 abnormally generates heat.

Abstract: Disclosed is a positive electrode for non-aqueous electrolyte secondary batteries, the positive electrode including a positive electrode material mixture layer which includes positive electrode active material particles and a binder. A curve representing a correlation between a distance from a current collector in the thickness direction of the positive electrode material mixture layer and an amount of the binder has a first maximum point, a minimum point, and a second maximum point. The minimum point corresponds to a position in a center area of the positive electrode material mixture layer in a thickness direction thereof, and the first and second maximum points correspond to a position nearer the current collector and a position further away from the current collector than the position corresponding to the minimum point, respectively.

Abstract: Methods for evaluating battery safety under internal short-circuit conditions are improved to eliminate variations in evaluation results and accurately evaluate battery safety under internal short-circuit conditions. An internal short-circuit is caused in a battery by using an internal short-circuit causing method in which battery information obtained upon the occurrence of an internal short-circuit hardly changes with the structure of the battery. At this time, the battery information is detected to accurately evaluate the safety of the battery upon the internal short-circuit and identify the safety level.

Abstract: A method for evaluating the safety of a battery under an internal short-circuit condition. The method for evaluating an internal short-circuit of a battery is characterized in that a short-circuit can be caused at a desired location inside the battery. According to the evaluation method of the invention, the evaluation result is not affected by the constitution of the outermost part of the battery unlike nail penetration tests which are conventional evaluation methods. Also, unlike crush tests which are conventional evaluation methods, the locations of short-circuits do not vary among tests and the safety under an internal short-circuit condition can be evaluated accurately.

Abstract: The present invention relates to an internal short circuit evaluation method for a battery including an electrode group including a positive electrode plate, a negative electrode plate and a separator disposed between the positive electrode plate and the negative electrode plate, and an outer jacket covering the electrode group, the method including the steps of: (I) processing the electrode group to a predetermined position of the electrode group, from the outside of the electrode group toward the inside thereof; and (II) causing a short circuit between a portion of the electrode plate and a portion of the negative electrode plate of the electrode group that are located inside from the predetermined position, and measuring battery information that is changed by the short circuit, and an evaluation apparatus used for the above-described method.

Abstract: A lithium secondary battery having enhanced safety, which includes an electrode group, a non-aqueous electrolyte and a battery can for housing them. The electrode group includes: a positive electrode having a strip-shaped positive electrode current collector and a material mixture layer carried thereon; a negative electrode having a strip-shaped negative electrode current collector and a material mixture layer carried thereon; a separator; and a porous heat resistant layer. The positive and negative electrodes are spirally wound with the separator and the porous heat resistant layer interposed therebetween. An outermost surface of the electrode group includes an exposed portion of either of the positive and negative electrode current collectors. The exposed portion faces an inner surface of the battery can with the separator interposed therebetween, and has opposite polarity to that of the battery can.

Abstract: The invention provides an evaluation method and an evaluation apparatus with which it is possible to know the safety level of batteries when an internal short circuit occurs through a chemical process, and a battery whose safety level has been determined with the evaluation method and the evaluation apparatus. A battery that has been charged to a predetermined voltage and into which conductive foreign matter has been incorporated is immersed in an electrolyte. The time at which the battery started to dissolve in the electrolyte is determined. Occurrence of an internal short circuit in the battery is detected based on a battery voltage. A time required for occurrence of short circuit is computed based on the above-described dissolution start time and the time of occurrence of the internal short circuit, and then output.

Abstract: A non-aqueous electrolyte secondary battery comprising at least a negative electrode having a current collector provided thereon with convex portions and columnar bodies formed on the convex portions, each of the columnar bodies comprising n stages (where n?2) of overlaid columnar body portions alternately tilted to different orientations along a longitudinal direction of the current collector, a positive electrode having a positive electrode current collector provided on both surfaces thereof with a positive electrode mixture layer containing a positive electrode active material capable of inserting and extracting lithium ions reversibly, and a separator interposed between the positive electrode and the negative electrode in a confronting manner, wherein tip portions of the columnar body portions at the uppermost stage of the columnar bodies on the negative electrode are tilted toward a trailing end of winding direction.

Abstract: A non-aqueous electrolyte secondary battery comprising a negative electrode having a current collector provided with convex portions and concave portions on both surfaces, a first columnar body formed in a tilting orientation on the convex portion on one of the surfaces of the current collector, and a second columnar body formed in a tilting orientation on the convex portion on the other surface, a positive electrode having a positive electrode current collector provided with a positive electrode mixture layer containing a positive electrode active material capable of reversibly inserting and extracting lithium ions on both surfaces, and a separator interposed between the positive electrode and the negative electrode in a confronting manner, wherein the first columnar body and the second columnar body on the negative electrode are tilted to an orthogonal direction of a winding direction of the current collector.

Abstract: An insulating resin layer is formed on part of the surface of a current collector of an electrode plate for a battery. The insulating resin layer is formed on at least part of a portion at which a mixture particle is not in contact with the surface of the current collector, in the area in which an electrode mixture layer is formed on the surface of the current collector.

Abstract: The nonaqueous solvent for a nonaqueous secondary battery of the present invention includes: a fluorinated cyclic carbonate having at least one fluorine in each designated location in the molecule; and a fluorinated phosphazene having at least one fluorine bound to a phosphorus atom in the phosphazene molecule and a ratio of the number of fluorine atoms to the number of phosphorus atoms being 4/3 or more. The fluorinated cyclic carbonate forms a good protective coat by reductive decomposition at a negative electrode, thereby improving cycle characteristics of the nonaqueous secondary battery. The fluorinated phosphazene suppresses generation of organic ions in the nonaqueous solvent, thereby reducing gas production in the nonaqueous secondary battery.

Abstract: A lithium secondary battery including: an electrode group, a non-aqueous electrolyte and a battery case housing the electrode group and the non-aqueous electrolyte, the electrode group including a positive electrode, a negative electrode and a separator layer interposed between the positive electrode and the negative electrode, wherein an end-of-charge voltage and an end-of-discharge voltage are set in such a manner that the electrode group has an energy density of not less than 700 Wh/L, the separator layer includes a porous heat-resistant layer, and a short circuit area A produced when an internal short circuit has occurred between the positive electrode and the negative electrode, and a reduced area B of the porous heat-resistant layer that is produced by heat generation satisfy 1?(A+B)/A?10.

Abstract: A battery pack includes: a plurality of secondary batteries; a housing for containing the secondary batteries; and at least one heat insulating layer for separating the secondary batteries from one another. The at least one heat insulating layer includes a foam material capable of foaming at a first predetermined temperature of 110° C. or more and less than 200° C. When the foam material foams, gas bubbles are produced in the heat insulating layer, so that the thickness of the heat insulating layer increases. The battery pack thus has excellent safety, exhibiting a high heat insulation effect in the event of abnormal heat generation of the batteries.

Abstract: A lithium ion secondary battery including an electrode for a lithium ion secondary battery, the electrode including: a current collector 30; an electrode active material layer 31 being laminated on a surface of the current collector 30 and including an electrode active material 32 capable of absorbing and desorbing lithium ions; a lithium ion conductive layer 13 being laminated on a surface of the electrode active material layer 31, and including a lithium ion conductive gel swelled with a non-aqueous electrolyte; and a porous heat-resistant layer 14 being laminated on a surface of the lithium ion conductive layer 13, and including insulating metal oxide particles.

Abstract: The nonaqueous solvent of the present invention for a nonaqueous secondary battery primarily contains a mixed solvent of a fluorinated cyclic carbonate having a structure in which one fluorine atom is bonded to each of two alkoxy group carbon atoms adjacent to carbonate oxygen atoms and a fluorinated acyclic carbonate having a similar structure. The fluorinated cyclic carbonate, in comparison with the unsubstituted cyclic carbonate, has not only an enhanced thermal stability but also a suppressed reactivity with the positive electrode in a charged state even at elevated temperatures. In addition, it forms a protective film which, with respect to a negative electrode in a charged state, suppresses reactivity between the negative electrode and the nonaqueous electrolyte solution. The fluorinated acyclic carbonate suppresses the reactivity with the positive electrode in a charged state and also lowers the viscosity of the nonaqueous electrolyte solution.

Abstract: A battery pack includes a plurality of batteries 12, and a pack case 13 containing the batteries 12. An electrode group is placed in a battery case 11, and an opening of the battery case 11 is sealed by a sealing plate 9. A first internal lead 6 electrically connected to one of positive and negative electrodes is connected to an inner bottom surface of the battery case 11. A second internal lead electrically connected to the other one of the positive and negative electrodes is connected to the sealing plate. The first internal lead 6 is arranged near an inner side surface of the battery case 11. Each of the batteries 12 is arranged in the pack case 13 with part of an outer side surface of the battery case 11 corresponding to the first internal lead 6 facing the inner side surface of the pack case 13.

Abstract: There is provided a film measuring device capable of accurately and easily measuring the thickness of a microporous film formed on a battery electrode plate over the entire area of the film. A color CCD sensor 8 shoots the microporous film. A video board 11 converts a color tone of a color image signal obtained by the image pickup into gradation data of respective color components of RGB. After the data conversion, an image processing board 12 extracts line images of the respective color components. A calculator 14 obtains the thickness of the microporous film by referring to pre-measured film thickness reference values corresponding to the gradation data of the green or blue color component, which are stored in a table storage 13 as reference thickness table data, using the gradation data of the line image of the green color component or the blue color component as lookup data.

Abstract: The present invention relates to an apparatus for evaluating an internal short circuit of a battery. An object of the invention is to provide an apparatus capable of evaluating whether or not an internal short circuit has occurred in an electrode group in consideration of pressure applied to the electrode group. An internal short circuit evaluation apparatus according to one embodiment of the invention includes at least a pressure member capable of operating independently and applying pressure to at least a predetermined position of the surface of the electrode group, and a short-circuiting member that is pressed into the predetermined position. An internal short circuit evaluation apparatus according to another embodiment of the invention includes a pressure member having an integrated short-circuiting member.

Abstract: In a battery, an electrode group (4) and an electrolyte are together sealed in a battery case (10). The electrode group (4) includes a positive electrode (1) and the negative electrode (2) which are wound or stacked with a separator (3) interposed therebetween. At least one of the positive electrode (1) and the negative electrode (2) includes a current collector (2A) and an active material layer (2B), and a lead (6) is electrically connected to an exposed portion (21) of the current collector (2A). The lead (6) is arranged to extend from the exposed portion (21) to the outside of the current collector (2A) such that the lead (6) straddles a first edge (21a) which is one of edges constituting the exposed portion (21), and is welded to the exposed portion (21) at a position close to the first edge (21a).

Abstract: Positive and negative electrode plates are respectively joined to positive and negative electrode terminals through leads. At least one of the leads joined to the positive or negative electrode plate is made of a stack of first and second metal layers. The first metal layer has a resistance higher than that of the second metal layer. The second metal layer has a melting point lower than that of the first metal layer. When a short-circuit current flows in the secondary battery, current is concentrated in the second metal layer to cause a blowout of the second metal layer, and then, an increase in an heat generation amount due to an increase in a current density of a short-circuit current flowing in the first metal layer causes a blowout of the first metal layer, thereby causing a blowout of the lead to interrupt the short-circuit current.