JP7060008B2 - Electrodes and power storage elements - Google Patents

Description

The present invention relates to an electrode and a power storage element.

Secondary batteries typified by lithium-ion secondary batteries are widely used in electronic devices such as personal computers and communication terminals, automobiles, etc. due to their high energy density. The secondary battery generally has a pair of electrodes consisting of a sheet-shaped positive electrode and a negative electrode, and an electrolyte interposed between the electrodes, and charges and discharges by transferring ions between the electrodes. It is configured as follows. Further, as a power storage element other than a secondary battery, capacitors such as lithium ion capacitors and electric double layer capacitors are also widely used.

The pair of electrodes usually form an electrode body that is alternately superposed by laminating or winding through a separator. As the electrode, as shown in FIG. 5A, an electrode having a structure in which an intermediate layer 102 is provided between the conductive electrode base material 101 and the active material layer 103 has been proposed (see Patent Document 1). ). The intermediate layer 102 in Patent Document 1 contains a carbon material and a binder, and the resistance of the electrode is reduced by the intermediate layer 102.

Japanese Unexamined Patent Publication No. 2015-103394

Normally, the active material layer 103 is coated so that the edge of the intermediate layer 102 is exposed, as shown in FIG. 5 (a). In this case, since the area of the active material layer 103 is smaller than that of the intermediate layer 102, it is not suitable for aiming at increasing the energy density of the power storage element.

On the other hand, as shown in FIG. 6, it is conceivable to apply the active material layer 203 so as to cover the edge of the intermediate layer 202. In this case, it is easy to increase the area of the active material layer 202, and it is expected that the energy density of the power storage element will also increase.

However, as shown in FIG. 6, when the active material layer 203 is provided so as to cover the edge of the intermediate layer 202, the edge of the active material layer 203 is more active than the portion laminated on the surface of the intermediate layer 202. Becomes thicker. Therefore, due to repeated expansion and contraction of the active material during charging and discharging, the active material layer 203 is likely to be peeled off from the edge of the active material layer 203 and the boundary portion with the intermediate layer 202. When peeling occurs from the edge of the active material layer 203, there is an inconvenience that the capacity of the electrode is reduced by the amount of the active material slipped off by the peeling.

The present invention has been made based on the above circumstances, and an object thereof is an electrode having a structure in which the active material layer covers the edge of the intermediate layer, but the active material layer is unlikely to be peeled off. It is an object of the present invention to provide a power storage element provided with such an electrode.

One aspect of the present invention made to solve the above problems is a conductive electrode base material, an intermediate layer laminated on a part of the surface of the electrode base material, and an activity laminated on the surface of the intermediate layer. The material layer is provided, and the active material layer has an edge portion in contact with the surface of the electrode base material, and the edge portion covers the edge of the intermediate layer and is laminated on the surface of the electrode base material. It is an electrode for a power storage element further provided with a coating layer in contact with the edge portion.

Another aspect of the present invention is a power storage element provided with the above electrodes.

According to the present invention, it is possible to provide an electrode having a structure in which the active material layer covers the edge of the intermediate layer, but the active material layer is unlikely to peel off, and a power storage element provided with such an electrode.

FIG. 1A is a partial cross-sectional view of an electrode according to an embodiment of the present invention, and FIG. 1B is a partial plan view of the electrode. FIG. 2 is a perspective view of a non-aqueous electrolyte secondary battery according to an embodiment of the power storage element of the present invention. FIG. 3 is a schematic partial cross-sectional view of an electrode body provided in the non-aqueous electrolyte secondary battery of FIG. FIG. 4 is a schematic view showing a power storage device configured by assembling a plurality of power storage elements according to an embodiment of the present invention. FIG. 5A is a partial cross-sectional view showing a conventional electrode, and FIG. 5B is a partial plan view of the electrode. FIG. 6 is a partial cross-sectional view showing an electrode obtained by improving a conventional electrode. FIG. 7 is a partial plan view showing a state of the electrode of FIG. 1 in the middle of manufacturing.

The electrode according to the embodiment of the present invention includes a conductive electrode base material, an intermediate layer laminated on a part of the surface of the electrode base material, and an active material layer laminated on the surface of the intermediate layer. The active material layer has an edge portion in contact with the surface of the electrode base material, the edge portion covers the edge of the intermediate layer, is laminated on the surface of the electrode base material, and is in contact with the edge portion. It is an electrode for a power storage element further provided with a layer.

Since the electrode has a structure in which the edge of the active material layer covers the edge of the intermediate layer, it is possible to increase the energy density of the power storage element. Further, since the electrode has a structure in which the coating layer presses the edge portion of the active material layer, it is possible to suppress the peeling of the active material layer from the edge portion.

It is preferable that the height of the surface of the coating layer is equal to or less than the height of the surface of the active material layer. If the surface of the coating layer becomes high, it may cause breakage when the electrodes are wound, or the coating layer portion may rise when the electrodes are laminated, which hinders productivity. Therefore, by doing so, the portion where the coating layer exists does not become thick when the electrodes are laminated, the productivity can be improved, and the size of the power storage element can be reduced.

In the plan view, it is preferable that the intermediate layer and the coating layer do not overlap with each other. By doing so, the height of the surface of the coating layer can be easily set to be equal to or lower than the height of the surface of the active material layer, and the thickening of the coating layer portion can be suppressed. The "planar view" refers to a state viewed from the normal direction with respect to the surface of the electrode base material. Specifically, in the electrode of the embodiment described later, FIG. 1B is a plan view.

It is preferable that the edge portion has a gradually decreasing portion whose height gradually decreases toward the edge of the active material layer, and the coating layer is in contact with only the gradually decreasing portion at the edge portion. By doing so, the height of the surface of the coating layer can be easily set to be equal to or lower than the height of the surface of the active material layer, the thickening of the coating layer portion can be suppressed, and the electrode group at the edge of the active material layer can be suppressed. It is possible to improve the adhesion with the material and further suppress the peeling of the active material layer from the edge portion.

It is preferable that the coating layer contains inorganic particles and a binder, and the content of the binder in the coating layer is 5% by mass or more and 90% by mass or less. As described above, by relatively increasing the content of the binder in the coating layer, the peeling suppressing function of the coating layer can be further enhanced.

The power storage element according to an embodiment of the present invention is a power storage element including the electrode. The energy storage element has a structure that facilitates high energy density of the energy storage element and is provided with the electrode in which the occurrence of peeling of the active material layer is suppressed. Therefore, the power storage element is highly reliable and can have a long life.

Hereinafter, the electrode and the power storage element according to the embodiment of the present invention will be described in detail.

<Electrode>
The electrode 10 in FIG. 1 includes an electrode base material 11, two intermediate layers 12, two active material layers 13, and two coating layers 14. The electrode 10 is an electrode for a power storage element. The electrode 10 may be a positive electrode or a negative electrode.

The electrode base material 11 has conductivity. In addition, having "conductivity" means that the volume resistivity measured according to JIS-H-0505 (1975) is ¹⁰⁷ Ω · cm or less. Further, the electrode base material 11 has a sheet-like shape.

When the electrode 10 is a positive electrode, a metal such as aluminum, titanium, tantalum or an alloy thereof is used as the material of the electrode base material 11 (positive electrode base material). Among these, aluminum and aluminum alloys are preferable from the viewpoint of the balance between potential resistance, high conductivity and cost. That is, aluminum foil is preferable as the positive electrode base material. Examples of aluminum or aluminum alloy include A1085P and A3003P specified in JIS-H-4000 (2014). On the other hand, when the electrode 10 is a negative electrode, a metal such as copper, nickel, stainless steel, nickel-plated steel or an alloy thereof is used as the material of the electrode base material 11 (negative electrode base material), and copper or a copper alloy is used. Is preferable. That is, a copper foil is preferable as the negative electrode base material. Examples of the copper foil include rolled copper foil and electrolytic copper foil.

The average thickness of the electrode base material 11 can be, for example, 5 μm or more and 50 μm or less. The "average thickness" means the average value of the thickness measured at any ten points. In the following, the term "average thickness" for other members and the like is also defined in the same manner.

The two intermediate layers 12 are laminated on a part of both sides of the electrode base material 11, respectively. That is, each intermediate layer 12 is laminated leaving one end of each of the front surface and the back surface of the electrode base material 11.

The intermediate layer 12 usually contains a conductive agent and a binder (binder). Since the intermediate layer 12 contains a conductive agent, it is possible to suppress an increase in contact resistance between the electrode base material 11 and the active material layer 13 due to the charge / discharge cycle.

Examples of the conductive agent include carbon materials and metals, but carbon materials are preferable. Examples of the carbon material include natural or artificial graphite, furnace black, acetylene black, ketjen black and the like.

As the binder, a binder that can fix a conductive agent and is electrochemically stable in the range of use is usually used. Examples of the binder include fluororesins (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene (PTFE), and tetrafluoroethylene-hexafluoropropylene). Polymers, etc.), thermoplastic resins such as polyethylene, polypropylene, polyimide; elastomers such as ethylene-propylene-diene rubber (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluororubber; polysaccharide polymers, etc. .. Among these, fluororesin is preferable, and PVDF is more preferable, from the viewpoint of heat resistance and the like.

The mass ratio of the conductive agent to the binder (conductive agent / binder) in the intermediate layer 12 is preferably 5/95 or more and 80/20 or less, and more preferably 10/90 or more and 50/50 or less. By setting the mass ratio of the conductive agent and the binder in the intermediate layer 12 within the above range, it is possible to secure good conductivity while providing sufficient adhesion.

The average thickness of the intermediate layer 12 can be, for example, 0.1 μm or more and 10 μm or less.

The two active material layers 13 are laminated on the surface (outer surface) of each intermediate layer 12. The active material layer 13 has an edge portion 15 in contact with the surface of the electrode base material 11. The edge portion 15 covers the edge portion 16 of the intermediate layer 12. The active material layer 13 does not have to completely cover the intermediate layer 12. That is, a part of the intermediate layer 12 other than the edge portion 15 may be exposed.

The active material layer 13 contains an active material and, if necessary, optional components such as a conductive agent, a binder, a thickener, and a filler. As each of these components, known components used for a general active material layer can be used.

When the electrode 10 is a positive electrode, the active material (positive substance active material) is, for example, a composite oxide (layered α-NaFeO ₂ ) represented by Li _x MO _y (M represents at least one transition metal). Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₃ , Li _x Ni _α Co _(1-α) O ₂ , Li _x Ni _α Mn _β Co _(1-α-β) O ₂ , having a type crystal structure Li _{1 + w} Ni _α Mn _β Co _(1-α-β-w) O ₂ , etc., Li _x Mn ₂ O ₄ , Li _x Ni _α Mn _(2-α) O ₄ , etc. having a spinel type crystal structure), Li _w Polyanionic compounds (LiFePO ₄ , LiMnPO ₄ , LiNiPO ₄ , LiCoPO ₄ ) represented by Me _x (AO _y ) _z (Me represents at least one kind of transition metal, and A represents, for example, P, Si, B, V, etc.). , Li ₃ V ₂ (PO ₄ ) ₃ , Li ₂ MnSiO ₄ , Li ₂ CoPO ₄ F, etc.). The elements or polyanions in these compounds may be partially substituted with other elements or anion species. In the electrode mixture layer, one kind of these compounds may be used alone, or two or more kinds may be mixed and used.

When the electrode 10 is a negative electrode, the active material (negative electrode active material) includes, for example, a metal or semi-metal such as Si or Sn; a metal oxide or semi-metal oxide such as Si oxide or Sn oxide; polyphosphorus. Acid compounds; Examples thereof include carbon materials such as graphite (graphite) and amorphous carbon (graphitizable carbon or non-graphitizable carbon).

Examples of the conductive agent and the binder that may be contained in the active material layer 13 include the same as those of the conductive agent and the binder in the intermediate layer 12. As the binder, a fluororesin is preferable, and PVDF is more preferable, from the viewpoint of heat resistance and the like.

Examples of the thickener include polysaccharide polymers such as carboxymethyl cellulose (CMC) and methyl cellulose.

The filler is not particularly limited as long as it does not adversely affect the performance of the power storage element. Examples of the main component of the filler include polyolefins such as polypropylene and polyethylene, silica, alumina, zeolite, and glass.

The lower limit of the content of the binder in the active material layer 13 is, for example, 1% by mass and may be 2% by mass. The upper limit of the content of the binder in the active material layer 13 is, for example, 10% by mass and 6% by mass.

The average thickness of the active material layer 13 can be, for example, 10 μm or more and 200 μm or less. The average thickness of the active material layer 13 is the average thickness of the flat portion (the portion other than the gradually decreasing portion 17 described later) of the active material layer 13 laminated on the intermediate layer 12.

The two coating layers 14 are laminated on the front and back surfaces of the electrode base material 11 so as to be in contact with the edge portion 15 of each active material layer 13. That is, the coating layer 14 is laminated on the electrode base material 11 so as to hold down the edge portion 15 of the active material layer 13. However, the coating layer 14 is not laminated up to the tip of the electrode base material 11, and the tip of the electrode base material 11 is exposed.

The coating layer 14 preferably contains inorganic particles and a binder. As a result, it is possible to more sufficiently suppress the peeling of the edge portion 15 of the active material layer 13 while ensuring the insulating property. The coating layer 14 may contain other components other than the inorganic particles and the binder.

Examples of the inorganic particles include inorganic oxides such as silica, alumina, titania, zirconia, magnesia, ceria, itria, zinc oxide and iron oxide, inorganic nitrides such as silicon nitride, titanium nitride and boron nitride, and silicon carbide. Calcium carbonate, aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolinite, kaolinite, boehmite, halosite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite, asbestos, aluminosilicate, calcium silicate , Magnesium silicate, kaolinite, silica sand, glass and the like.

Examples of the binder include the same binders as those in the intermediate layer 12. Among these, fluororesin is preferable, and PVDF is more preferable, from the viewpoint of heat resistance and the like.

As the lower limit of the content of the binder in the coating layer 14, 5% by mass is preferable, 10% by mass is preferable, 20% by mass is more preferable, and 30% by mass is more preferable. By setting the content of the binder in the coating layer 14 to the above lower limit or higher, the peeling suppressing function of the active material layer 13 with respect to the edge portion 15 can be further enhanced. On the other hand, as the upper limit of this content, 90% by mass is preferable, 80% by mass is more preferable, and 70% by mass is further preferable. By setting the content of the binder in the coating layer 14 to the above upper limit or less, the insulating property, heat resistance, and the like can be improved.

The peel strength of the coating layer 14 with respect to the electrode base material 11 is higher than the peel strength of the active material layer 13 with respect to the electrode base material 11. As a result, the peeling suppressing function of the covering layer 14 with respect to the edge portion of the active material layer 13 is effectively exerted. The peel strength can be determined according to the 180 ° peel test of JIS-Z0237: 2009.

The peel strength of the coating layer 14 with respect to the electrode base material 11 can be increased by increasing the content of the binder contained in the coating layer 14 or by using a binder having a strong adhesive force. When the active material layer 13 and the coating layer 14 contain the same type of binder, the peeling strength of the coating layer 14 with respect to the electrode base material 11 is increased by increasing the content ratio of the binder in the coating layer 14. It can be made higher than the peel strength of the layer 13 with respect to the electrode base material 11.

It is preferable that the height (h1) of the surface of the coating layer 14 is equal to or less than the height (h2) of the surface of the active material layer 13. These heights (h1) and (h2) refer to the height from the surface of the electrode base material 11. Further, the surface height (h1) of the covering layer 14 means the height (maximum height) of the highest position on the surface of the covering layer 14. Similarly, the height (h2) of the surface of the active material layer 13 means the height (maximum height) of the highest position on the surface of the active material layer 13.

The average thickness of the coating layer 14 can be, for example, 1 μm or more and 100 μm or less. The average thickness of the coating layer 14 refers to the average thickness of the portion that does not overlap with the active material layer 13 (the portion directly laminated on the electrode base material 11) in a plan view. Further, the 10 points for measuring the thickness for calculating the average thickness of the coating layer 14 are the point on the most active material layer 13 side of the portion that does not overlap with the active material layer 13 and the active material layer 13 of the coating layer 14. Is an arbitrary 10 points in the intermediate region equally divided into 3 parts between the end points on the opposite side (exposed portion side of the base material).

It is preferable that the intermediate layer 12 and the covering layer 14 do not overlap with each other in the electrode 10 in a plan view (see FIG. 1 (b)). That is, it is preferable that the coating layer 14 is laminated in a region outside the tip of the intermediate layer 12. By laminating the coating layer 14 in this way, swelling of the coating layer 14 is less likely to occur, and the surface height (h1) of the coating layer 14 is set to be equal to or less than the surface height (h2) of the active material layer 13. It will be easier.

Further, the edge portion 15 of the active material layer 13 has a gradually decreasing portion 17 (inclined portion) whose height gradually decreases toward the end edge of the active material layer 13. In the active material layer 13, the portion laminated on the intermediate layer 12 is flat. On the other hand, the portion laminated outside the edge of the intermediate layer 12 (the portion directly laminated on the electrode base material 11) becomes substantially the gradually decreasing portion 17. In the edge portion 15 of the active material layer 13, it is preferable that the coating layer 14 is in contact with only the gradually decreasing portion 17. That is, it is preferable that the coating layer 14 is not in contact with the flat portion of the active material layer 13. By laminating the coating layer 14 in this way, swelling of the coating layer 14 is less likely to occur, and the surface height (h1) of the coating layer 14 is set to be equal to or less than the surface height (h2) of the active material layer 13. It will be easier.

The electrode 10 can be used for both a positive electrode and a negative electrode, but is preferably used as a positive electrode. Further, the electrode 10 can be adopted in both the positive electrode and the negative electrode.

The method for manufacturing the electrode 10 is not particularly limited, but it can be performed, for example, by laminating each layer on the electrode base material 11 by coating. That is, the method for manufacturing the electrode 10 is to laminate the intermediate layer 12 on the surface of the electrode base material 11, for example, by coating.
By coating, the active material layer 13 is laminated on the surface of the intermediate layer 12, and by coating, the coating layer 14 is laminated on the surface of the electrode base material 11 so as to be in contact with the edge of the active material layer 13. To prepare for.

When laminating the active material layer 13, the edge portion 15 of the active material layer 13 is laminated so as to cover the edge portion 16 of the intermediate layer 12. After laminating each layer, defective products may be discriminated using a sensor or the like, if necessary. When such a defective product discrimination method is adopted, since the electrode 10 has a structure in which the edge portion 15 of the active material layer 13 covers the end edge 16 of the intermediate layer 12, discrimination after the active material layer 13 is provided. In this case, foreign matter adhering to the vicinity of the edge of the surface of the electrode 10 and uneven coating of the edge of the active material layer 13 can be easily detected, which is preferable.

Specifically, the reason why the structure of the electrode 10 is advantageous for discriminating defective products is as follows. FIG. 5B shows a state in which the active material layer 103 is coated as a conventional electrode so that the edge of the intermediate layer 102 is exposed. In the manufacturing process, after coating the active material layer 103, it is determined whether or not foreign matter adheres to the electrode surface and whether the active material layer 103 is coated evenly by using a sensor or the like. May be done. On the other hand, the intermediate layer 102 and the active material layer 103 are generally black because they usually contain a carbon material as a conductive agent. Therefore, as shown in FIG. 5B, when black foreign matter X (for example, the coating liquid of the active material layer 103) is attached near the edge of the electrode surface, the foreign matter X is in the middle. It is difficult to detect this foreign matter X when it is attached to the surface of the layer 102. Further, even if there is uneven coating on the edge of the active material layer 103, it is difficult to detect it. Therefore, it becomes difficult to detect defective products, and an expensive sensor or the like having high discriminating power is required. On the other hand, as shown in FIG. 7, in the production of the electrode 10, the active material layer 13 is laminated so as to cover the edge of the intermediate layer. In this case, since the foreign matter X adheres to the surface of the electrode base material 11, it is easy to detect due to the difference in brightness and the like. In addition, uneven coating on the edge of the active material layer 13 can be easily detected.

As the material used for coating each layer, a coating liquid or the like in which the components forming each layer are dispersed with water or an organic solvent can be used. In addition, each layer may be laminated by, for example, electrostatic coating. Further, the coating liquid of the next layer may be applied after the applied coating liquid is dried, or the coating liquid of the next layer may be applied while the coating liquid is not dried. It may be processed and dried all at once.

<Power storage element>
FIG. 2 shows a schematic view of a rectangular non-aqueous electrolyte secondary battery 20 which is an embodiment of the power storage element according to the present invention. In the non-aqueous electrolyte secondary battery 20, the electrode body 21 (not shown in FIG. 2) shown in FIG. 3 is housed in the case 22.

As shown in FIG. 3, the electrode body 21 is formed by laminating a positive electrode 10 and a negative electrode 23 via a separator 24. The electrode body 21 has a structure in which a plurality of positive electrodes 10 and a plurality of negative electrodes 23 are laminated, or a structure in which the positive electrode 10 and the negative electrode 24 are wound flat in a laminated state. In addition, in FIG. 3, only a part of the electrode body 21 is schematically shown.

As the positive electrode 10 of FIG. 3, the electrode 10 of FIG. 1 can be adopted. Therefore, the same reference numerals as those in FIG. 1 are added and the description thereof will be omitted.

The negative electrode 23 has a negative electrode base material 25 and two negative electrode active material layers 26 laminated on both sides of the negative electrode base material 25. The negative electrode base material 25 and the negative electrode active material layer 26 are the same as those described in the case where the electrode 10 is the negative electrode in the electrode base material 11 and the active material layer 13 in the electrode 10 of FIG. The negative electrode 23 may have an intermediate layer arranged between the negative electrode base material 25 and the negative electrode active material layer 26. Further, as the negative electrode, the one having the structure of the electrode 10 of FIG. 1 can also be adopted.

The separator 24 is not particularly limited, and a known separator for a power storage element can be used. As the material of the separator, for example, a woven fabric, a non-woven fabric, a porous resin film, or the like is used. Among these, a porous resin film is preferable. As the main component of the porous resin film, polyolefins such as polyethylene and polypropylene are preferable from the viewpoint of strength. Further, a porous resin film in which these resins and a resin such as aramid or polyimide are combined may be used. It is also possible to use a separator in which an inorganic layer is laminated on a porous resin film.

As the case 22 in FIG. 2, a known aluminum case, resin case, or the like that is usually used as a case for a general non-aqueous electrolyte secondary battery can be used. The case 22 has a lid 27 and a case body 28. Further, the lid 27 is provided with a positive electrode terminal 29 and a negative electrode terminal 30. The positive electrode terminal 29 is connected to the positive electrode 10 of the electrode body 21, and the negative electrode terminal 30 is connected to the negative electrode 23 of the electrode body 21.

The case 22 in which the electrode body 21 is housed is filled with a non-aqueous electrolyte. As the non-aqueous electrolyte, a known non-aqueous electrolyte usually used for a non-aqueous electrolyte secondary battery can be used. As the non-aqueous electrolyte, one in which an electrolyte salt is dissolved in a non-aqueous solvent can be used.

Examples of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC) and butylene carbonate (BC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and the like. Chain carbonate and the like can be mentioned.

Examples of the electrolyte salt include lithium salt, sodium salt, potassium salt, magnesium salt, onium salt and the like, but lithium salt is preferable. Examples of the lithium salt include inorganic lithium salts such as LiPF ₆ , LiPO ₂ F ₂ , LiBF ₄ , LiClO ₄ , LiN (SO ₂ F) ₂ , LiSO ₃ CF ₃ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO). ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ CF ₃ ) (SO ₂ C ₄ F ₉ ), LiC (SO ₂ CF ₃ ) ₃ , LiC (SO ₂ C ₂ F ₅ ) ₃ and other fluorinated hydrocarbon groups A lithium salt having a above can be mentioned.

Further, as the non-aqueous electrolyte, a molten salt at room temperature, an ionic liquid, a polymer solid electrolyte and the like can also be used.

<Other embodiments>
The present invention is not limited to the above embodiment, and can be implemented in various modifications and improvements in addition to the above embodiment. In the above embodiment, the mode in which the power storage element is a non-aqueous electrolyte secondary battery has been mainly described, but other power storage elements may be used. Examples of other power storage elements include capacitors (electric double layer capacitors, lithium ion capacitors) and the like. Further, it may be a power storage element in which the electrolyte is an aqueous solution. Further, unlike the embodiment shown in FIG. 1, the present invention includes an electrode model in which an intermediate layer, an active material layer, and a coating layer are formed only on one side of an electrode base material.

The configuration of the power storage element according to the present invention is not particularly limited, and examples thereof include a cylindrical battery, a square battery (rectangular battery), and a flat battery. The present invention can also be realized as a power storage device including a plurality of the above-mentioned power storage elements. An embodiment of the power storage device is shown in FIG. In FIG. 4, the power storage device 40 includes a plurality of power storage units 41. Each power storage unit 41 includes a plurality of power storage elements 42 (for example, the non-aqueous electrolyte secondary battery 20 in FIG. 2). The power storage device 40 can be mounted as a power source for an electric vehicle (EV), a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), or the like.

The present invention can be applied to a personal computer, an electronic device such as a communication terminal, a power storage element used as a power source for an automobile, and an electrode for a power storage element provided therein.

10 Electrode (positive electrode)
11 Electrode base material 12 Intermediate layer 13 Active material layer 14 Coating layer 15 Edge part 16 Edge part 17 Gradual reduction part 20 Non-aqueous electrolyte secondary battery 21 Electrode body 22 Case 23 Negative electrode 24 Separator 25 Negative electrode base material 26 Negative electrode active material layer 27 Lid Body 28 Case body 29 Positive electrode terminal 30 Negative terminal 40 Power storage device 41 Power storage unit 42 Power storage element 101, 201 Electrode base material 102, 202 Intermediate layer 103, 203 Active material layer X Foreign matter

Claims (5)

A conductive electrode base material, an intermediate layer laminated on a part of the surface of the electrode base material, and an active material layer laminated on the surface of the intermediate layer are provided.
The active material layer has an edge portion in contact with the surface of the electrode base material, and the edge portion covers the edge of the intermediate layer.
A coating layer laminated on the surface of the electrode base material and in contact with the edge portion is further provided .
The portion of the active material layer laminated on the intermediate layer is flat and is flat.
An electrode for a power storage element in which the intermediate layer and the coating layer do not overlap in a plan view . The electrode according to claim 1, wherein the height of the surface of the coating layer is equal to or less than the height of the surface of the active material layer. The edge portion has a tapering portion whose height gradually decreases toward the edge of the active material layer.
The electrode according to claim 1 or 2 , wherein the coating layer is in contact with only the gradually decreasing portion at the edge portion. The coating layer contains inorganic particles and a binder, and contains
The electrode according to any one of claims 1 to 3 , wherein the content of the binder in the coating layer is 5% by mass or more and 90% by mass or less. A power storage element including the electrode according to any one of claims 1 to 4 .

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