リチウムイオン電池

US9356271
(Abstract)
"An electrochemical stack comprising（から成る、含む）carrier ions（＊複数）, an anode comprising an anode active material layer, a cathode comprising a cathode active material layer, a separator between the anode and the cathode comprising（＊係り：separator comprising；cathodeは既述の"the cathode"で、それが"a porous dielectric material"を有するとすればそれは新情報であって、「既述の、多孔性の絶縁材を有するカソード」ではおかしいから、だと思う）a porous dielectric material and a non-aqueous electrolyte, and an ionically permeable conductor layer located（配置）between the separator and an electrode active material layer."

"FIELD OF THE INVENTION

The present invention generally relates to structures for use in energy storage devices, to energy storage devices incorporating（有する、内蔵）such structures, and to methods for producing such structures and energy devices.

BACKGROUND OF THE INVENTION

Rocking chair （ロッキングチェア）or insertion secondary batteries are a type of energy storage device in which carrier ions, such as lithium, sodium or potassium ions, move between an anode electrode and a cathode electrode through an electrolyte. The secondary battery may comprise（から成る、有する）a single battery cell, or two more battery cells that have been electrically coupled to form the battery, with each battery cell comprising an anode electrode, a cathode electrode, and an electrolyte.

In rocking chair battery cells, both the anode and cathode comprise materials into which a carrier ion inserts（挿入）and extracts（脱離）. As（時、に際し） a cell is discharged, carrier ions are extracted from the anode and inserted into the cathode. As a cell is charged, the reverse process occurs: the carrier ion is extracted from the cathode and inserted into the anode.

FIG. 1shows a cross sectional view of an electrochemical stack of an existing energy storage device, such as a non-aqueous, lithium-ion battery. The electrochemical stack 1 includes a cathode current collector 2, on top of which（の上、上部）a cathode layer 3 is assembled（組み付け、組み立て、配設）. This layer is covered by a microporous separator 4, over which（の上、上部）an assembly（組立体）of an anode current collector 5 and an anode layer 6 are placed. This stack is sometimes covered with another separator layer (not shown) above the anode current collector 5, rolled and stuffed into a can, and filled with a non-aqueous electrolyte to assemble a secondary battery.

The anode and cathode current collectors pool（溜める）electric current from the respective（それぞれ、各々）active electrochemical electrodes and enables transfer of the current to the environment outside the battery. A portion of an anode current collector is in physical contact with the anode active material while a portion of a cathode current collector is in contact with（接触）the cathode active material. The current collectors do not participate in（関与）the electrochemical reaction and are therefore restricted to materials that are electrochemically stable in the respective electrochemical potential ranges for the anode and cathode.

In order for a current collector（＊不定冠詞）to bring current（＊無冠詞）to the environment outside the battery, it is typically connected to a tab, a tag, a package feed-through（フィードスルー） or a housing feed-through, typically collectively referred to as contacts. One end of a contact is connected to one or more current collectors while the other end passes through the battery packaging for electrical connection to the environment outside the battery. The anode contact is connected to the anode current collectors and the cathode contact is connected to the cathode current collectors by welding, crimping（圧着）, or ultrasonic bonding or is glued（接着）in place with an electrically conductive glue.

During a charging process, lithium（＊無冠詞）leaves the cathode layer 3 and travels（移動）through the separator 4 as a lithium ion（＊不定冠詞）into the anode layer 6. Depending upon the anode material used（＊cf. "used anode material"）, the lithium ion either intercalates（インターカレート、挿入される）(e.g., sits in a matrix of an anode material without forming an alloy) or forms an alloy. During a discharge process, the lithium leaves the anode layer 6, travels through the separator 4 and passes through to the cathode layer 3. The current conductors conduct electrons from the battery contacts (not shown) to the electrodes or vice versa.

Existing energy storage devices, such as batteries, fuel cells, and electrochemical capacitors, typically have two-dimensional laminar（積層）architectures（構造）(e.g., planar or spiral-wound laminates（積層体）) as illustrated in FIG. 1 with（付帯、付加説明）a surface area of each laminate being roughly equal to its geometrical footprint (ignoring porosity and surface roughness).

Three-dimensional batteries have been proposed in the literature（文献；＊定冠詞） as ways to improve（改善）battery capacity and active material utilization. It has been proposed that a three-dimensional architecture may be used to provide higher surface area and higher energy as compared to（比較、比べ）a two dimensional, laminar battery architecture. There is a benefit to making a three-dimensional energy storage device due to the increased amount of energy that may be obtained out of a small geometric area. See, e.g., Rust et al., WO2008/089110 and Long et. al, “Three-Dimensional Battery Architectures,” Chemical Reviews, (2004), 104, 4463-4492.

New anode and cathode materials have also been proposed as ways to improve the energy density, safety, charge/discharge rate, and cycle life of secondary batteries. Some of these new high capacity materials, such as silicon, aluminum, or tin anodes in lithium batteries have significant volume expansion that causes disintegration and exfoliation（剥離）from its existing electronic current collector during lithium insertion（挿入）and extraction（脱離）. Silicon anodes, for example, have been proposed for use as a replacement for carbonaceous electrodes since silicon anodes have the capacity to provide significantly greater energy per unit volume of host material for lithium in lithium battery applications. See, e.g., Konishiike et al., U.S. Patent Publication No. 2009/0068567; Kasavajjula et al., “Nano- and Bulk-Silicon-Based Insertion Anodes for Lithium-Ion Secondary Cells,” Journal of Power Sources 163 (2007) 1003-1039. The formation of lithium silicides when lithium is inserted into the anode results in a significant volume change which can lead to crack formation（割れ、亀裂）and pulverisation（粉砕）of the anode. As a result, capacity of the battery can be decreased as the battery is repeatedly discharged and charged.

Monolithic electrodes, i.e., electrodes comprising a mass of electrode material that retains its a shape without the use of a binder, have also been proposed as an alternative to improve performance (gravimetric and volumetric energy density, rates, etc) over particulate electrodes that have been molded（成形）or otherwise formed into a shape（形状）and depend upon a conductive agent or binder to retain the shape of an agglomerate of the particulate material. A monolithic anode, for example, may comprise a unitary（単一）mass of silicon (e.g., single crystal silicon, polycrystalline silicon, amorphous silicon or a combination thereof) or it may comprise an agglomerated（凝集）particulate mass that has been sintered or otherwise treated（処理）to fuse the anodic material together and remove any binder. In one such exemplary embodiment, a silicon wafer may be employed as a monolithic anode material for a lithium-ion battery with（状態）one side of the wafer coupled to a first cathode element through a separator, while the other side is coupled to a second cathode element opposing（対向）it. In such arrangements, one of the significant technical challenges（課題）is the ability to collect and carry current from the monolithic electrode to the outside of the battery while efficiently utilizing the space available inside the battery.

The energy density of conventional batteries may also be increased by reducing inactive component weights and volumes to pack the battery more efficiently. Current batteries use relatively thick current collectors since the foils that make up the current collectors are used with a minimum thickness requirement in order to be strong enough to survive the active material application process. Advantages in performance can be anticipated（期待、予測）if an invention was made in order to separate the current collection from processing constraints.

Despite the varied approaches, a need remains for（必要）improved battery capacity and active material utilization."