KR20130055712A - Electrode assembly of improved stability and secondary battery the same - Google Patents

Abstract

The present invention includes a positive electrode including a positive electrode active material layer coated on one or both sides of the current collector; A negative electrode including a negative electrode active material layer coated on one or both surfaces of a current collector; A separator interposed between the anode and the cathode; And at least two through-holes perforated in the positive electrode and / or the negative electrode to allow gas generated during an initial charge and discharge of the battery to pass therethrough, thereby providing an electrode assembly and a lithium secondary battery including the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrode assembly having improved safety and a secondary battery including the electrode assembly.

The present invention relates to an electrode assembly having improved safety and a secondary battery including the same, and more particularly, to a positive electrode including a positive electrode active material layer coated on one or both surfaces of a current collector, and coated on one or both surfaces of a current collector. A negative electrode including a negative electrode active material layer, the separator interposed between the positive electrode and the negative electrode; And an electrode assembly having a structure including two or more through holes perforated in the cathode and / or the anode so that gas generated during an initial charge / discharge process of the battery may pass therethrough, and a lithium secondary battery including the same.

As technology development and demand for mobile devices are increasing, the demand for batteries as energy sources is rapidly increasing, and accordingly, a lot of researches on batteries capable of meeting various demands have been conducted.

Typically, in terms of the shape of a battery, there is a high demand for a prismatic secondary battery and a pouch-type secondary battery which can be applied to products such as mobile phones with a small thickness, and has advantages such as high energy density, discharge voltage, There is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

In addition, secondary batteries are classified according to the structure of the electrode assembly having a cathode / separation membrane / cathode structure. Representatively, a jelly having a structure in which long sheet-shaped anodes and cathodes are wound with a separator interposed therebetween -Roll (electrode) electrode assembly, a stack (stacked type) electrode assembly in which a plurality of positive and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator, and the positive and negative electrodes of a predetermined unit are interposed through a separator And a stacked / folding electrode assembly having a structure in which a bi-cell or full cells stacked in a state are wound.

Recently, due to the high capacity of the battery, much attention has been paid to the large-sized case and the processing of a thin material. Accordingly, a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet The pouch-shaped battery of the present invention has been gradually increased in usage due to low manufacturing cost, small weight, and easy shape deformation.

Most secondary batteries including the pouch-type battery undergo a process of activating the battery by charging and discharging in the manufacturing process of the battery cell. Thus, in order to manufacture the final battery cell, the gas generated in the activation process must be removed. It is called a degas process.

The degassing process is conventionally performed by cutting the end portion of the sealed part of the battery case. However, the degassing process takes a lot of time to remove the gas, leading to an increase in manufacturing cost, gas and surplus. There is a problem that a large number of defects occur in the sealing process due to heat fusion because the electrolyte is not completely removed.

In this regard, FIGS. 1 and 2 illustrate a battery cell degassed through a conventional degas process.

1 and 2, the gas generated in the activation process is not sufficiently discharged to the outside, it can be seen that the bending occurs on the surface of the battery case or the electrode, respectively.

As described above, if the gas generated during the initial charge and discharge process is not sufficiently removed, the shape of the battery is changed, which seriously affects the safety of the battery. There is a problem.

In addition, since the demand of customers is changing due to the increase in the size and size of the secondary battery, when the conventional small battery cell manufacturing process is applied to the production of large battery cells, gas discharge inside the jelly-roll is not smooth during the degassing process. There is a problem that the failure rate of the battery is high.

Therefore, there is a high need for a technology that can fundamentally solve these problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

After extensive research and various experiments, the inventors of the present application have a structure including two or more through holes perforated in the positive electrode and / or the negative electrode to allow gas generated during the initial charge and discharge of the battery to pass therethrough. The electrode assembly was developed, and it was confirmed that such an electrode assembly not only improves the yield of the degas process, but also improves the amount of the electrolyte solution impregnated with the electrode, thus completing the present invention.

Accordingly, the electrode assembly according to the present invention includes a positive electrode including a positive electrode active material layer coated on one or both surfaces of a current collector; A negative electrode including a negative electrode active material layer coated on one or both surfaces of a current collector; A separator interposed between the anode and the cathode; And two or more through holes formed in the anode and / or the cathode to allow gas generated during an initial charge and discharge of the battery to pass therethrough.

In the lithium secondary battery, the electrolyte is decomposed on the surface of the negative electrode active material during the continuous charge / discharge process, and gas is generated. During the initial charging / discharging process, the SEI film is formed on the surface of the negative electrode active material. Therefore, as described above, the process of activating the battery by charging and discharging is necessary for the formation of such an SEI film, and is required before the final battery cell is manufactured.

In this regard, since the electrode assembly according to the present invention has two or more through-holes perforated in the anode and / or the cathode, it is possible to easily and quickly remove the gas and surplus electrolyte generated during the activation process in comparison with the conventional electrode assembly. .

In addition, the electrolyte may be easily moved into the electrode assembly through a plurality of through holes formed in the electrode assembly, thereby increasing the impregnation of the electrode with respect to the electrolyte. Therefore, even if the area of the battery becomes large, wetting can be made uniform and the process time can be shortened, thereby ultimately improving the safety and life characteristics of the battery. Moreover, this high impregnation helps to maintain excellent rate characteristics even at high rate charge and discharge conditions.

The electrode assembly according to the present invention may include through holes of various structures in order to efficiently discharge the gas generated in the activation process.

As a preferred example, the through holes may be formed in a structure in which the electrode active material layer and the current collector communicate with each other.

More preferably, the through holes may include one or more through holes (anode through holes) drilled in the anode and one or more through holes (anode through holes) drilled in the cathode.

In the above structure, the anode through hole and the cathode through hole may preferably have a positional arrangement in communication with each other.

In this case, the separator may be perforated in addition to a position communicating with the anode through hole and the cathode through hole.

As the separator, a polymer such as polypropylene made of pores having a predetermined diameter is used. As the above-mentioned hole is perforated at a position communicating with the anode through hole and the cathode through hole, the gas generated in the electrode assembly can be more efficiently Can be discharged to the outside.

In the present invention, the through holes may be formed in various diameters, preferably 0.5 to 10% of the upper and lower widths of the positive electrode or the negative electrode. If the diameter of the through holes is too small, there is a problem that gas is not easy to discharge, and if the diameter of the through holes is too large, the amount of the electrode active material at the communicating position may decrease, which may lead to a decrease in capacity of the battery. not.

The diameter of the cathode through holes may be 80 to 99.5% of the diameter of the cathode through holes. As described above, the diameter of the cathode through-hole is preferably smaller than the diameter of the anode through-hole.

The through holes may be formed in plural on the positions corresponding to the widths of the unit cells when the unit cells are positioned to manufacture the electrode assembly. Preferably, the through holes are formed on the horizontal central axis of the positive electrode or the negative electrode. As a guide, it can be located within 20 to 80% of the top and bottom width.

Specifically, since the exhaust of the gas generated from the inside of the gas generated in the electrode assembly is a particular problem, it is preferable in terms of efficiency to place the through holes in the above range.

The shape and number of the through holes is not particularly limited as long as the shape and number can efficiently discharge the gas. Preferably, the through holes may have a circular, elliptical, polygonal or slit shape.

Preferably, the total area of the through holes may be 0.5 to 20% of the total area of the positive electrode or the negative electrode.

On the other hand, in the electrode assembly according to the present invention, the positive electrode, for example, is produced by applying and drying a slurry prepared by adding a positive electrode mixture containing a positive electrode active material to a solvent such as NMP on a positive electrode current collector, The positive electrode mixture may further include a binder, a conductive material, a filler, a viscosity modifier, and an adhesion promoter.

The cathode current collector generally has a thickness of 3 to 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, the surface of stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel Surface treated with carbon, nickel, titanium, silver, or the like can be used. The positive electrode current collector may have fine unevenness formed on the surface thereof to increase the adhesive force of the positive electrode active material as in the case of the negative electrode current collector. Alternatively, the positive electrode current collector may have various properties such as a film, sheet, foil, net, porous body, Form is possible.

The cathode active material is a material capable of causing an electrochemical reaction. Examples of the lithium transition metal oxide include lithium cobalt oxide (LiCoO ₂ ) containing two or more transition metals and substituted with one or more transition metals, lithium Layered compounds such as nickel oxide (LiNiO ₂ ); Lithium manganese oxide substituted with one or more transition metals; Formula _{LiNi 1-y M y O 2} ( where, M = Co, Mn, Al , Cu, Fe, Mg, B, Cr, Zn or Ga and Lim, 0.01≤y≤0.7 include one or more elements of the element) A lithium nickel-based oxide represented by the following formula: _{Li 1 + z Ni 1/3 Co 1/3} Mn 1/3 O 2, Li 1 + z Ni 0.4 Mn 0.4 Co 0.2 O 2 , such as _{Li 1 + z Ni b Mn c} Co 1- (b + c + d _{) M d O (2-e} ) A e ( where, -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2 , 0≤e≤0.2, b + c + d <1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl; lithium nickel cobalt manganese composite oxide; Formula Li _{1 + x} M _{1 - y} M ' _y PO _{4- z} X _z , wherein M = transition metal, preferably Fe, Mn, Co or Ni, M' = Al, Mg or Ti, X = Olivine-based lithium metal phosphate represented by F), S or N, and -0.5≤x≤ + 0.5, 0≤y≤0.5, and 0≤z≤0.1, and the like.

Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), cellulose, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber, various copolymers, high molecular weight polyolefins such as polyolefin, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, Vinyl alcohol, and the like.

The conductive material is not particularly limited as long as it has electrical conductivity without causing any chemical change in the battery, for example, graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used. Concrete examples of commercially available conductive materials include acetylene black series such as Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc.), Ketjenblack, EC (Armak Company), Vulcan XC-72 (Cabot Company), and Super P (Timcal).

The filler is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The viscosity modifier may be added up to 30% by weight based on the total weight of the negative electrode mixture as a component for adjusting the viscosity of the electrode mixture so that the mixing process of the electrode mixture and the coating process on the current collector may be easy. Examples of such viscosity modifiers include carboxymethylcellulose, polyvinylidene fluoride and the like, but are not limited thereto. In some cases, the above-described solvent may play a role as a viscosity adjusting agent.

The adhesion promoter may be added in an amount of 10% by weight or less based on the binder, for example, oxalic acid, adipic acid, Formic acid, acrylic acid derivatives, itaconic acid derivatives, and the like.

The negative electrode is prepared by, for example, applying and drying a slurry prepared by adding a negative electrode mixture including a negative electrode active material to a solvent such as NMP on a negative electrode current collector, and optionally, a binder, a conductive material, It may further include other components described in connection with the configuration of the positive electrode, such as filler, viscosity regulator, and adhesion promoter.

The negative electrode collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be formed of a material such as copper, stainless steel, aluminum, nickel, titanium, fired carbon, surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the negative electrode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

Examples of the negative electrode active material include carbon and graphite materials such as natural graphite, artificial graphite, expanded graphite, carbon fiber, non-graphitizable carbon, carbon black, carbon nanotube, fullerene and activated carbon; Metals such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pt, and Ti that can be alloyed with lithium and compounds containing these elements; Complexes of metals and their compounds and carbon and graphite materials; Lithium-containing nitrides, and the like. Among them, a carbon-based active material, a tin-based active material, a silicon-based active material, or a silicon-carbon based active material is more preferable, and these may be used singly or in combination of two or more.

The separator prevents a short circuit between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; Sheets or nonwovens made of glass fibers or polyethylene are used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The electrode assembly according to the present invention may be stacked in various forms, for example, may be stacked in a jelly-roll type, a stack type, a stack / fold type, and the like, and may preferably be a stack / fold type. Since the electrode assemblies stacked in a stack or stack / folding form have a structure in which the unit assemblies are sequentially stacked with the anode and the cathode interposed therebetween, manufacturing the anode and the cathode first is required to make such an electrode assembly. need. That is, in order to manufacture a unit electrode such as a positive electrode and a negative electrode, a process of notching a continuous electrode sheet coated with an electrode active material on one surface or both surfaces at unit electrode intervals is required.

In addition, since the through holes of the electrode assembly according to the present invention can be designed to be formed at the same time as the notching of the electrode tab in the notching process, there is an advantage that does not require an additional manufacturing process for forming the through holes.

The present invention also provides a secondary battery having a structure in which a lithium salt-containing non-aqueous electrolyte solution is impregnated with the electrode assembly embedded in a battery case.

The lithium salt-containing nonaqueous electrolyte solution is composed of an electrolyte solution and a lithium salt. As the electrolyte solution, a nonaqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte may be used.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and gamma Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxorone, formamide, dimethylformamide, dioxolon , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxy methane, dioxorone derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate and ethyl propionate can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer containing an ionic dissociation group and the like may be used.

As the inorganic solid electrolyte, for example, Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides, sulfates, and the like of Li, such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge / discharge characteristics and the flame retardancy, the electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, in order to impart nonflammability, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included, or carbon dioxide gas or the like may be further included to improve high temperature storage characteristics.

The battery case may have a cylindrical shape, a square shape, or a pouch type of a laminated sheet including a metal layer and a resin layer, which is well known in the art, and thus a detailed description thereof will be omitted.

The secondary battery may be preferably a lithium secondary battery.

Such a secondary battery may not only be usefully used for a battery cell used as a power source for a small device, but also may be preferably used as a unit cell in a battery pack including a plurality of battery cells used as a power source for medium and large devices. . Furthermore, it can be preferably used for battery packs that require high output power, power characteristics, etc. depending on the operating conditions and require long-term use.

Preferred examples of the battery pack include a power tool moving by being driven by an electric motor; An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart; Power storage devices, etc., but is not limited thereto.

As described above, the electrode assembly according to the present invention includes a positive electrode, a negative electrode, and a separator, and through holes are perforated in the positive electrode and / or the negative electrode, thereby easily removing the gas generated during the activation process to improve the safety of the battery. It can greatly improve.

In addition, the electrode assembly according to the present invention greatly improves the impregnation of the electrolyte, thereby improving the manufacturing process of the battery, such an electrode assembly can be used in a lithium secondary battery exhibiting superior safety and life characteristics than conventional.

1 is a photograph of the exterior of a battery cell subjected to a conventional degas process;
2 is a photograph of an electrode assembly having a conventional degassing process;
3A is a schematic front view of an electrode assembly according to one embodiment of the present invention;
3B is a schematic front view of an electrode assembly according to another embodiment of the present invention;
4 and 5 are front schematic views of a positive electrode sheet and a negative electrode sheet for manufacturing the electrode assembly of FIG. 3;
FIG. 6 is a schematic plan view of a positive electrode sheet, a separator, and a negative electrode sheet for manufacturing the electrode assembly of FIG. 3; FIG.
7 is a schematic plan view of a positive electrode sheet, a separator, and a negative electrode sheet according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings according to the embodiments of the present invention, but the scope of the present invention is not limited thereto.

3A and 3B show front schematic views of an electrode assembly according to an embodiment of the present invention, respectively.

4 and 5 are schematic front views of the positive electrode sheet and the negative electrode sheet for manufacturing the electrode assembly of FIG. 3.

In addition, FIG. 6 is a schematic plan view of the positive electrode sheet, the separator, and the negative electrode sheet for manufacturing the electrode assembly of FIG. 3.

Referring to these drawings, the electrode assembly 100 may be formed on both surfaces of the positive electrode 20 and the negative electrode current collector 46 including the positive electrode active material layers 22 and 24 coated on both surfaces of the positive electrode current collector 26. The negative electrode 40 includes the negative electrode active material layers 42 and 44 coated thereon, and a separator 30 interposed between the positive electrode 20 and the negative electrode 40.

In addition, nine through holes 12 and 14 are drilled through the anode 20 and the cathode 40 based on the cathode and anode units, respectively, to allow gas to be generated during the initial charge and discharge of the battery.

The through holes have a structure in which the electrode active material layer and the current collector communicate with each other, and the nine through holes 12 drilled through the positive electrode 20 and the nine through holes 14 drilled through the negative electrode 40 are formed. have.

In addition, the anode through holes 12 and the cathode through holes 14 have a positional arrangement in communication with each other.

The diameter of the through holes is 3% of the upper and lower widths (a, b) of the anode 20 and the cathode 40, and the diameter of the cathode through holes 14 is 95% of the diameter of the anode through holes 12. Has a size.

The through holes are located within 60% of the upper and lower widths c and d with respect to the horizontal center axis e of the anode 20 and the cathode 40, and the shapes of the through holes have a circular shape in plan view .

 The total area of the through holes is 10% of the total area of the anode 20 or the cathode 40.

7 is a schematic plan view of a positive electrode sheet, a separator, and a negative electrode sheet according to another embodiment of the present invention.

Referring to FIG. 7, except that the separator through hole 16 is additionally drilled at the position of the separator 32 communicating with the anode through hole 12 and the cathode through hole 14, the structure of FIG. Since it is the same as the detailed description thereof will be omitted.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (16)

A positive electrode including a positive electrode active material layer coated on one or both surfaces of a current collector;
A negative electrode including a negative electrode active material layer coated on one or both surfaces of a current collector;
A separator interposed between the anode and the cathode; And
Two or more through holes perforated in the positive electrode and / or the negative electrode to allow the gas generated during the initial charge and discharge of the battery to pass therethrough;
Electrode assembly, characterized in that consisting of a structure comprising a. The electrode assembly of claim 1, wherein the through holes have a structure in which the electrode active material layer and the current collector are in communication with each other. The electrode assembly of claim 1, wherein the through holes comprise at least one through hole (anode through hole) drilled in the anode and at least one through hole (cathode through hole) drilled in the cathode. The electrode assembly of claim 3, wherein the anode through hole and the cathode through hole have a positional arrangement in communication with each other. The electrode assembly of claim 4, wherein the separator is perforated at a position in communication with the anode through hole and the cathode through hole. The electrode assembly of claim 1, wherein the diameters of the through holes are 0.5 to 10% of the upper and lower widths of the positive electrode and the negative electrode. The electrode assembly of claim 3, wherein the diameter of the cathode through hole is 80 to 99.5% of the diameter of the anode through hole. The electrode assembly of claim 1, wherein the through holes are positioned within 20 to 80% of the vertical width of the through holes based on the horizontal center axis of the anode or the cathode. The electrode assembly according to claim 1, wherein the through holes have a circular, elliptical, polygonal or slit shape in plan view. The electrode assembly according to claim 1, wherein the total area of the through holes is 0.5 to 20% of the total area of the positive electrode or the negative electrode. The electrode assembly of claim 1, wherein the electrode assembly is stacked in a jelly-roll type, a stack type, or a stack-fold type structure. The secondary battery, characterized in that the lithium salt-containing non-aqueous electrolyte is impregnated with the electrode assembly according to any one of claims 1 to 11 embedded in the battery case. The method of claim 12, wherein the battery case is a secondary battery, characterized in that the pouch-like structure of the cylindrical, rectangular or laminated sheet. The secondary battery of claim 12, wherein the battery is a lithium secondary battery. A battery pack comprising two or more secondary batteries according to claim 12 as a unit cell. The battery pack according to claim 15, wherein the battery pack is used in an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

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