By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventor Okuno, Moriaki (Kanagawa, JP), filed on December 4, 2012, was published online on July 3, 2018.
The patent's assignee for patent number 10014504 is Murata Manufacturing Co. Ltd. (Kyoto, JP).
News editors obtained the following quote from the background information supplied by the inventors: "The present technology relates to a separator, a battery, a battery pack, an electronic device, an electric vehicle, a power storage device, and a power system. More specifically, the present technology relates to a separator in which a second layer is provided on at least one face of a first layer.
"In the past, polyolefin microporous polymer films, such as polypropylene and polyethylene, or multilayer films thereof, have been widely used as a separator. However, these separators suffer from a problem in that air hole clogging and contraction occur due to the heat generated by internal short circuits or overcharging of the battery. When the separator contracts due to the internal heat of the battery, the positive electrode and the negative electrode come into direct contact at the contracted portion, and this contact causes various problems to occur.
"Accordingly, recently, to solve these problems with the separator, research has been carried out relating to separators in which a porous film that includes ceramic particles and a binder is provided on a surface. In a separator having such a configuration, heat resistance is conferred to the polyolefin material, so that melting and contraction of the polyolefin material under a high temperature environment of 120.degree. C. or more can be suppressed.
"In such a separator, not only is heat resistance conferred to the polyolefin material, but oxidation resistance, mechanical strength and the like can also be conferred. Since these effects are increased the greater the content of the ceramic particles is, in most of the related art, it is said that a range of 80% or more is preferred for the content of the ceramic particles.
"However, for vehicle-mounted batteries that have been drawing attention in recent years, such batteries need to achieve a high power density. In order to meet this requirement, various investigations regarding the respective battery parts have been performed. There is a need for a technique to increase the pore size and the porosity in the separator.
"To meet this requirement, Patent Literature 1 proposes a technique for increasing the pore size and the porosity by appropriately suppressing solution/solvent replacement and solvent diffusion by, before dipping a polymer solution in a poor solvent bath, absorbing moisture to form a thin porous film on the surface.
"Further, to meet the need for even higher battery capacity, alloy-based negative electrodes are being investigated that have silicon (Si) or tin (Sn) as new negative electrode materials. Since such an alloy-based negative electrode tends to expand in volume during charging, there is a need for a separator that can absorb the expansion in volume of the electrode by crumpling."
As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventor's summary information for this patent: "Technical Problem
"However, the technique described in Patent Literature 1 increases the pore size and the porosity of a porous film that only includes a resin material. Patent Literature 1 does not describe a technique for increasing the pore size and the porosity of a porous film that includes a resin material and ceramic particles. Further, in Patent Literature 1, there is no description regarding a technique for absorbing expansion in the volume of an electrode for a porous film that includes a resin material and ceramic particles.
"Therefore, it is an object of the present technology to provide a separator that has a large pore size and a high porosity and that is capable of absorbing electrode expansion, a battery including such separator, and a battery pack, an electronic device, an electric vehicle, a power storage device, and a power system that include that battery.
"Solution to Problem
"In order to solve the above-mentioned problem, according to the first embodiment of the present technology, there is provided a separator including a first layer of a porous substance, and a second layer that is provided on at least one face of the first layer and that includes a resin material and particles. The second layer has an agglomeration network structure of the particles.
"According to the second embodiment of the present technology, there is provided battery that includes a positive electrode, a negative electrode, an electrolyte, and a separator. The separator includes a first layer of a porous substance, and a second layer that is provided on at least one face of the first layer and that includes a resin material and particles. The second layer has an agglomeration network structure of the particles.
"The battery pack, electronic device, electric vehicle, power storage device, and power system according to the present technology are characterized by including a battery having the separator according to the first embodiment of the present technology, or the battery according to the second embodiment of the present technology.
"In the present technology, since the second layer has an agglomeration network structure of particles, a large pore size and a high porosity can be obtained. Further, since the agglomeration network structure of particles is a structure that crumples by applying pressure, when a separator having the second layer provided on at least one face of the first layer is included in a battery, electrode expansion can be absorbed by the crumpling of the second layer of the battery that occurs with the expansion of the electrode.
"Advantageous Effects of Invention
"According to the present invention, a separator can be realized that has a large pore size and a high porosity, and is capable of absorbing electrode expansion. Additional features and advantages are described herein, and will be apparent from the following Detailed Description and the figures."
For additional information on this patent, see: Okuno, Moriaki. Separator, Battery, Battery Pack, Electronic Device, Electric Vehicle, Power Storage Device, and Power System. U.S. Patent Number 10014504, filed December 4, 2012, and published online on July 3, 2018. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=10014504.PN.&OS=PN/10014504RS=PN/10014504
Keywords for this news article include: Asia, Japan, Business, Technology, Murata Manufacturing Co. Ltd..
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